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Non-anticoagulant Effects of Heparin: An Overview
Abstract
Heparin has long been known to possess biological effects that are unrelated to its anticoagulant activity. In particular, much emphasis has been placed upon heparin, or novel agents based upon the heparin template, as potential anti-inflammatory agents. Moreover, heparin has been reported to possess clinical benefit in humans, including in chronic inflammatory diseases and cancer, that are over and above the expected effects on blood coagulation and which in many cases are entirely separable from this role. This chapter aims to provide an overview of the non-anticoagulant effects that have been ascribed to heparin, from those involving the binding and inhibition of specific mediators involved in the inflammatory process to effects in whole system models of disease, with reference to the effects of heparin that have been reported to date in human diseases.
... Moreover, LMWH have anti-inflammatory and immunomodulant effects and play a key role in the defense against bacteria and other foreign materials [22]. Because of the biological effects that are unrelated to its anti-coagulant activity, LMWH have clinical benefits in several human conditions, such as acute inflammatory reaction, chronic inflammatory diseases, and cancer [26]. Furthermore, LMWH may play a role in embryo implantation and placentation, as largely demonstrated in pregnancies from assisted reproductive technologies (ART) [23]. ...
... Moreover, LMWH interact with many growth factors, such as basic fibroblast growth factor and transforming growth factor-ß [45]. By binding to these factors, heparin may cause the inhibition of vascular smooth muscle cell proliferation, a process that is involved in the tissue remodelling described in several diseases such as atherosclerosis and vascular stenosis [26]. ...
... In addition to the inhibition of the release and the activity of inflammatory mediators, heparin is also effective in limiting the recruitment of inflammatory cells to tissues and has an important impact on the immune system [26]. It is known that leukocyte infiltration of both the maternal-fetal interface (deciduitis) and villi (villitis) is a common feature both in severe PE and FGR [49]. ...
Low molecular weight heparins (LMWH) have been largely studied for their use during pregnancy. The biology and the pharmacology of these molecules are well known and may be summarized in three main mechanisms of action: anti-coagulant, anti-inflammatory, and immunomodulant. The clinical implications of these drugs during pregnancy are mainly related to their action on the placenta, because of the presence of specific molecular and cellular targets, particularly at the trophoblast-endometrial interface. As well as for the prevention and treatment of thromboembolism, LMWH have been largely investigated for the improvement of embryo implantation and for the prevention of placenta-related complications such as preeclampsia, fetal growth restriction, and intrauterine fetal death. However, data on this topic are still unclear. The present review discusses the biological features, the mechanisms of action, and the possible contribution of LMWH to the success of placentation along pregnancy, pointing out the need for future basic science and clinical researches in this important field with the final aim to improve clinical practice in high-risk pregnancies.
... The serendipitous observation of improved symptoms in patients with UC who were treated with UFH for thrombosis has opened up a potential new therapeutic avenue for the treatment of UC [37]. The discovery of anti-inflammatory properties of UFH and LMWHs independent of their anticoagulant effects has fuelled interest in the potential use of heparins in the management of UC [38]. ...
... Endogenous heparin is found in the secretory granules of mast cells. It is believed that the heparin regulates the storage and release of mast cell components during tissue injury as a defense mechanism against invading pathogens, rather than for anticoagulation purposes [38]. Commercially available UFH is extracted and purified mainly from porcine intestinal mucosa [40]. ...
... The effect of heparins in UC is thought to be based on their anti-inflammatory and mucosal healing activities [38]. Mechanisms by which heparins are postulated to exert their beneficial effects in UC are discussed (FIGURE 3). ...
Current drug therapies for ulcerative colitis (UC) are not completely effective in managing moderate-to-severe UC and approximately 20% of patients with severe UC require surgical interventions. Heparins, polydisperse mixtures of non-anticoagulant and anticoagulant oligosaccharides, are widely used as anticoagulants. However, heparins are also reported to have anti-inflammatory properties. Unfractionated heparin was initially used in patients with UC for the treatment of rectal microthrombi. Surprisingly, it was found to be effective in reducing UC-associated symptoms. Since then, several pre-clinical and clinical studies have reported promising outcomes of heparins in UC. In contrast, some controlled clinical trials demonstrated no or only limited benefits, thus the potential of heparins for the treatment of UC remains uncertain. This review discusses potential mechanisms of action of heparins, as well as proposed reasons for their contradictory clinical effectiveness in the treatment of UC.
... In a review of 26 stents placed in 23 patients with malignant SVCS caused by non-small cell lung cancer, all but one patient had improvement in symptoms. 57 The reocclusion rate was found to be 11% within 3 days to 8 months of placement. Reocclusions, however, were amenable to secondary interventions with a secondary patency rate of 92%. ...
... Sometimes the filter can still be retrieved using advanced techniques. 2,18,26,56,57 Moreover, existing data suggest both filter retrieval and exclusion techniques have similar long-term patency. 18 Based upon clinical judgment, the safest and most feasible method should be pursued. ...
Techniques in Vascular and Interventional Radiology: Venous Edition 2018
... Heparins, a group of glycosaminoglycans with a wide spectrum of biological activities [8], are widely used as anticoagulant drugs for the prevention and treatment of thrombosis in a variety of conditions, including cancer [9]. Heparins are known to have additional biological effects that are unrelated to their anticoagulant activity [10,11]. Experimental evidences suggest that heparins have the capability to interfere with mechanisms of tumor cell/EC interaction [12]. ...
... Along this line, our group could demonstrate that heparins (both unfractionated heparin (UFH) and low-molecular-weight heparins (LMWH) significantly counteract the pro-angiogenic and pro-thrombotic stimuli exerted by different tumor cells, including APL cells, on the endothelium [6,13,14]. In addition, both UFH and LMWH can inhibit leukocyte adhesion and infiltration in vitro and in vivo [11]. There are no studies evaluating the role of heparins on the adhesion of APL cells to the endothelium. ...
Adhesion of acute promyelocytic leukemia (APL) cells to endothelial cells (EC) is among the mechanisms of the APL-associated coagulopathy, responsible for early hemorrhagic deaths in affected patients. We compared the effects of dalteparin and enoxaparin, two low-molecular-weight heparins (LMWH), and unfractionated heparin (UFH), on APL NB4 adhesion to micro- (HMEC-1) and macro-vascular EC (HUVEC), in resting and interleukin-1β (IL-1β)-stimulated conditions. The heparin effect on EC adhesion molecule (ICAM-1, VCAM-1, E-selectin) expression was also assessed. In HMEC-1, dalteparin inhibited IL1β-induced NB4 adhesion by 80%, enoxaparin by 52%, and UFH by 44%. Similar results were obtained in HUVEC. This was associated with a significant decrease of VCAM-1 and ICAM-1 expression. In conclusion, we show that LMWH significantly counteract APL cell adhesion to the vessel wall, by modulating EC adhesion molecule expression. This property of heparins may represent one approach for hampering excess clotting activation and microthrombi deposition in APL.
... In addition, these anti-inflammatory properties can be mimicked by non-anticoagulant species of heparin such as Odesulfated heparin [9,10]. Heparin is a polysaccharide that acts via a wide range of anti-inflammatory mechanisms, which makes it a broad spectrum anti-inflammatory drug in addition to, and independent of, its anticoagulant activities [11]. The discovery of novel polysaccharides that share the anti-inflammatory actions of heparin, whilst lacking anticoagulant activity, provides the basis for the development of a novel class of anti-inflammatory drugs. ...
... This observation is important because it further suggests that the anti-inflammatory activities of polysaccharides are independent of anticoagulant activities, supporting other work with heparin like molecules [11]. Previous studies have demonstrated inhibition of neutrophil elastase by a wide range of GAG's [45,56] and sulfated polysaccharide from seaweeds, such as fucoidan [6]. ...
It is now recognized that certain polysaccharides can exhibit anti-inflammatory activity, including the glycosaminoglycan (GAG) heparin that is widely used as an anti-coagulant drug. However, it would be desirable to identify molecules that retain the anti-inflammatory actions of heparin, but that are devoid of significant anti-coagulant activity. In the present study we have identified a number of novel GAG and GAG-like polysaccharides (VRP327) from marine organisms, most of which were resistant to digestion by heparinase II and chondroitinase ABC. Fourier transform infra-red spectrum (FTIR) revealed species with variable degrees of sulphation and monosaccharide analysis revealed a range of sugar compounds, which in some cases included sugars not present in mammalian GAGs. ¹H NMR spectra of these species are consistent with the structures of complex polysaccharides. From an initial screening cascade to remove compounds having significant anti-coagulant activity and no overt cytotoxicity, we identified a high molecular weight oversulphated dermatan sulphate (VRP327) isolated from the tunicate Ascidiella aspersa which was fully characterised by NMR spectroscopy. This material was depolymerised to produce well characterized low molecular weight fractions which were demonstrated to be non-toxic, with low levels of anti-coagulant activity, and to have demonstrable anti-inflammatory activity assessed in several in vitro and in vivo models. The identification of low molecular weight polysaccharides having significant anti-inflammatory activity without significant anti-coagulant activity may provide novel templates for the development of a novel class of anti-inflammatory drugs.
... Heparin is, by and large, more highly sulfated than HS and will usually outcompete HS for binding to protein ligands. HS is involved in embryonic development, inflammation, immune defense, and cell growth , and the ability of heparin to interfere in these processes or mimic the action of HS forms the molecular basis for several potential therapeutic uses of heparin and heparin-like compounds (Lever and Page, 2012). ...
... Beyond its well recognized anticoagulant effects, it has long been appreciated that heparin possesses a wide range of other biologic actions (Jaques, 1979). In particular, heparin exhibits a broad range of activities Pharmacology of Heparin and Related Drugs that are of potential relevance to control of the inflammatory response (Lever and Page, 2012) and progression of cancer, particularly metastasis , which shares many similarities with leukocyte diapedesis in inflammation. Furthermore, there is growing interest in heparin and related drugs in controlling infectious diseases, ranging from effects on prions (Vieira et al., 2014) and viruses (de Boer et al., 2012) to effects on bacteria (McCrea et al., 2014). ...
Heparin has been recognized as a valuable anticoagulant and antithrombotic for several decades and is still widely used in clinical practice for a variety of indications. The anticoagulant activity of heparin is mainly attributable to the action of a specific pentasaccharide sequence that acts in concert with antithrombin, a plasma coagulation factor inhibitor. This observation has led to the development of synthetic heparin mimetics for clinical use. However, it is increasingly recognized that heparin has many other pharmacological properties, including but not limited to antiviral, anti-inflammatory, and antimetastatic actions. Many of these activities are independent of its anticoagulant activity, although the mechanisms of these other activities are currently less well defined. Nonetheless, heparin is being exploited for clinical uses beyond anticoagulation and developed for a wide range of clinical disorders. This article provides a "state of the art" review of our current understanding of the pharmacology of heparin and related drugs and an overview of the status of development of such drugs.
... ODSH is produced by the desulfation of unfractionated heparin, reducing its anticoagulant effect to <5% of the potency of unfractionated heparin, yet retaining the anti-inflammatory properties. In mammals heparin is exclusively seen in mast cells residing in the connective and mucosal tissues [12]. This phenomenon suggests that endogenous heparin may have a physiological role in the ...
... It has been reported that heparin can inhibit the activation of a variety of inflammatory cells [18,19]. This effect has been partially attributed to the binding and resulting neutralization of inflammatory mediators and enzymes secreted during an inflammatory response directed for the stimulation of inflammatory cells [12]. Heparin has also been shown to inhibit the release of certain enzymes and cytotoxic mediators released from cells involved in the inflammatory response process and subsequent tissue ...
Many radiation events have involved a high incidence of radiation combined injuries. Victims of radiation events succumb to serious infections as a consequence of bacterial translocation and sepsis. Exacerbation of the risk of infection by radiation combined burn injury (RCBI) further heightens vulnerability. There are currently no suitable countermeasures that exist for RCBIs. We evaluated 2-0, 3-0 desulfated heparin (ODSH), an anti-inflammatory and anticoagulant agent as a potential countermeasure to RCBI. Female B6D2F1/J mice (12-week) were subjected to 9.5 Gy (LD70/30 for RCBI) whole-body bilateral 60Co gamma-photon radiation (0.4 Gy/min), followed by dorsal skin burn injury under anesthesia (∼15% total-body-surface area burn). Mice were injected subcutaneously with ODSH (25 mg/kg every 12 h; days 1-2 and 17.5 mg/kg every 12 h; days 3-7) or vehicle (sterile saline of equal volume) for 7 days post-injury and further administered topical gentamicin (0.1% cream; days 1-10) and oral levofloxacin (100 mg/kg; days 3-16). Mice were euthanized on day 30 following water consumption, body mass and survival analysis. Our data showed ODSH had no effect on radiation injury (RI)-induced mortality (45% ODSH vs. 45% VEH; n=20). However interestingly, ODSH treatment significantly reduced survival after RCBI (12% ODSH vs. 41% VEH; n=22, p<0.05). Furthermore, ODSH did not affect water consumption or body mass accrual after RI or RCBI. ODSH was not able to counteract the negative alterations in hematology, splenocytes, or bone marrow cell counts after RI or RCBI. These data illustrate that ODSH in combination with antibiotic treatments, may not be a mitigating countermeasure for RCBI.
... In clinical practice, heparins are widely used for the treatment and prophylaxis of venous thromboembolism [6]. However, many studies have demonstrated therapeutic usefulness of heparins apart from their anticoagulant activity, of which their anti-inflammatory properties have attracted much interest among researchers around the world [7]. ...
... Although heparins are well-known for their non-anticoagulant effects [7], their exact mode of action in UC remain unclear. Different mechanisms including a reduced infiltration of leukocytes as well as pro-inflammatory mediators have been postulated [11,61,62]. ...
Inflammatory bowel diseases, such as ulcerative colitis, cause significant morbidity and decreased quality of life. The currently available treatments are not effective in all patients, can be expensive and have potential to cause severe side effects. This prompts the need for new treatment modalities. Enoxaparin, a widely used antithrombotic agent, is reported to possess anti-inflammatory properties and therefore we evaluated its therapeutic potential in a mouse model of colitis. Acute colitis was induced in male C57BL/6 mice by administration of dextran sulfate sodium (DSS). Mice were treated once daily with enoxaparin via oral or intraperitoneal administration and monitored for colitis activities. On termination (day 8), colons were collected for macroscopic evaluation and cytokine measurement, and processed for histology and immunohistochemistry. Oral but not intraperitoneal administration of enoxaparin significantly ameliorated DSS-induced colitis. Oral enoxaparin-treated mice retained their body weight and displayed less diarrhea and fecal blood loss compared to the untreated colitis group. Colon weight in enoxaparin-treated mice was significantly lower, indicating reduced inflammation and edema. Histological examination of untreated colitis mice showed a massive loss of crypt architecture and goblet cells, infiltration of immune cells and the presence of edema, while all aspects of this pathology were alleviated by oral enoxa-parin. Reduced number of macrophages in the colon of oral enoxaparin-treated mice was accompanied by decreased levels of pro-inflammatory cytokines. Oral enoxaparin significantly reduces the inflammatory pathology associated with DSS-induced colitis in mice and could therefore represent a novel therapeutic option for the management of ulcerative colitis.
... Its topical, ophthalmic and parenteral formulations were also used to treat burns and lesions. In low doses, heparin showed activity in several experimental models of inflammation as well as in the treatment of human chronic pulmonary diseases, by inhalation, or topically in allergic rhinitis [5]. It was suggested that heparin has effect on connective and tissue components as observed in emphysema, cystic fibrosis, rheumatoid arthritis, psoriasis, perodontitis, mucopolysaccharidosis, wound healing and tumor invasion [6]. ...
Aim
To determine the effect of heparin administered during the early post urethral trauma period on inflammation and spongiofibrosis in rats.
Materials and methods
The study included 24 male rats that were randomized into 3 groups of 8 each. The urethra was traumatized using a 24-G needle sheath in all rats. Group 1 (control group) received intraurethral saline 0.9% injected b.i.d. for 27 days, group 2 received intraurethral Na-heparin (liquemine-Roche) 1500 IU kg⁻¹ injected b.i.d. for 27 days, and group 3 received intraurethral Na-heparin 1500 IU kg⁻¹ injected b.i.d and saline 0.9% s.i.d. for 27 days. On day 28 the rats’ penises were degloved and penectomy was performed. Inflammation, spongiofibrosis, and congestion in the urethra were investigated in each group.
Results
A statistically significant difference was found between the three groups (control, heparin, and heparin + saline) in the histopathological status of spongiofibrosis, inflammation, and congestion, respectively (P = 0.0001, P = 0.002, P = 0.0001). Severe spongiofibrosis was observed in six (75%) of the rats in group 1 (control group), whereas severe spongiofibrosis was not observed in group 2 (heparin) or group 3 (heparin + saline).
Conclusion
We observed that intraurethral Na-heparin 1500 IU kg⁻¹ injectioned during the early posturethral trauma period in rats significantly decreased inflammation, spongiofibrosis, and congestion.
... A considerable literature suggests the potential non-anticoagulant mechanisms underlying the treatment of COVID-19 patients with nonanticoagulant heparin derivatives (Fig. 4) [52][53][54][55], which includes: 1. Heparanase inhibition (HPSE). The loss of endothelial barrier function in the case of COVID-19, which leads to pulmonary oedema and proteinuria, can be partially attributed to increased HPSE activitydegrading the endothelial glycocalyx. ...
The ongoing pandemic of COVID-19, caused by the infection of SARS-CoV-2, has generated significant harm to the world economy and taken numerous lives. This syndrome is characterized by an acute inflammatory response, mainly in the lungs and kidneys. Accumulated evidence suggests that exogenous heparin might contribute to the alleviation of COVID-19 severity through anticoagulant and various non-anticoagulant mechanisms, including heparanase inhibition, chemokine and cytokine neutralization, leukocyte trafficking interference, viral cellular-entry obstruction, and extracellular cytotoxic histone neutralization. However, the side effects of heparin and potential drawbacks of administering heparin therapy need to be considered. Here, the current heparin therapy drawbacks were covered in great detail: structure-activity relationship (SAR) mystery, potential contamination, and anticoagulant activity. Considering these unfavorable effects, specific non-anticoagulant heparin derivatives with antiviral activity could be promising candidates to treat COVID-19. Furthermore, a structurally diverse library of non-anticoagulant heparin derivatives, constructed by chemical modification and enzymatic depolymerization, would contribute to a deeper understanding of SAR mystery. In short, targeting non-anticoagulant mechanisms may produce better therapeutic effects, overcoming the side effects in patients suffering from COVID-19 and other inflammatory disorders.
... Heparin is one of the commonly used anticoagulants in clinic with an established role in prevention and treatment of arterial and venous thromboembolism [1]. Besides the prominence of its anticoagulant application in clinic, heparin also possesses potent anti-oxidant and anti-inflammatory activities, immune regulation and other biological activities [2]. Several experimental studies in rats showed that heparin treatment reduced infarct area after limb or intestinal ischemia/reperfusion (I/R) [3,4]. ...
Heparin has been documented to reduce myocardial injury caused by ischemia/reperfusion (I/R), but its clinical application is limited due to its strong intrinsic anticoagulant property. Some desulfated derivatives of heparin display low anticoagulant activity and may have potential value as therapeutic agents for myocardial I/R injury. In this study, we observed that 6-O-desulfated heparin, a desulfated derivative of heparin, shortened the activated partial thromboplastin time and exhibited lower anticoagulant activity compared with heparin or 2-O-desulfated heparin (another desulfated derivative of heparin). Then, we explored whether 6-O-desulfated heparin could protect against myocardial I/R injury, and elucidated its possible mechanisms. Administration of 6-O-desulfated heparin significantly reduced creatine kinase activity, myocardial infarct size and cell apoptosis in mice subjected to 30 min of myocardial ischemia following 2 h of reperfusion, accompanied by a reverse in miR-199a-5p elevation, klotho downregulation and reactive oxygen species (ROS) accumulation. In cultured H9c2 cells, the mechanism of 6-O-desulfated heparin against myocardial I/R injury was further explored. Consistent with the results in vivo, 6-O-desulfated heparin significantly ameliorated hypoxia/reoxygenation-induced injury, upregulated klotho and decreased miR-199a-5p levels and ROS accumulation, and these effects were reversed by miR-199a-5p mimics. In conclusion, these results suggested that 6-O-desulfated heparin with lower anticoagulant activity attenuated myocardial I/R injury through miR-199a-5p/klotho and ROS signaling. Our study may also indicate that 6-O-desulfated heparin, as an excellent heparin derivative, is a potential therapeutic agent for myocardial I/R injury.
... Studies have shown that the anti-inflammatory role of heparin is mainly because of the blockade of P-selectin and L-selectin. 5,6 In a randomized study by Katakkar to explore the use of heparin as a topical anti-inflammatory and antithrombotic agent, the author showed that heparin application decreased the incidence of pain, redness, and swelling. They concluded that use of heparin is safe, effective, and well tolerated. ...
Introduction Heparin is useful in inflammatory conditions for amelioration of symptoms by altering the microcellular environment. This study was aimed at evaluation of the role of heparin in patients with cellulitis on antibiotics.
Methodology In our prospective nonrandomized comparative study, the subjects were divided into two groups: group A treated with subcutaneous injection of unfractionated heparin plus antibiotics and group B with antibiotics alone. Comparison was done in terms of improvement in clinical parameters like erythema (cellulitis area), edema (measuring limb girth), pain (visual analog scale), total leucocyte count, and duration of hospital stay.
Results Total of 96 patients were divided into two groups of 48 each. In the experimental group, there was improvement in mean area of cellulitis with decrease of 32.36% compared with 10.99% in controls treated with antibiotics at day 5 (p < 0.001). There was 26.27% decrease in edema compared with 12.87% (p < 0.001). There was 45.36% decrease of pain compared with 38.02% (p < 0.001). There was 29.18% drop in total leucocyte counts compared with 25.87% (p < 0.001). There was reduced duration of stay at 7.15 days compared with 9.23 days in controls.
Conclusion The addition of heparin with antibiotic therapy in cellulitis hastens recovery with faster amelioration of symptoms and shorter hospital stay.
... Heparin, due to its ability to bind and neutralize inflammatory mediators and enzymes released during an inflammatory process and with several mechanisms, such as neutralization of cationic mediators, inhibition of adhesion molecules, and the inhibition of heparinase, that are potentially relevant because involved in leukocyte recruitment into tissues, can modulate the inflammatory response (Lever and Page, 2012). As this anti-inflammatory activity suggests a potential benefit in the management of COPD, we tested the effects of inhaled unfractionated heparin at 75,000 IU and 150,000 IU twice daily for 21 days in patients with moderate to severe COPD (Shute et al., 2018). ...
The inhaled route is critical for the administration of drugs to treat patients suffering from COPD, but there is still an unmet need for new and innovative inhalers to address some limitations of existing products that do not make them suitable for many COPD patients. The treatment of COPD, currently limited to the use of bronchodilators, corticosteroids, and antibiotics, requires a significant expansion of the therapeutic armamentarium that is closely linked to the widening of knowledge on the pathogenesis and evolution of COPD. The great interest in the development of new drugs that may be able to interfere in the natural history of the disease is leading to the synthesis of numerous new molecules, of which however only a few have entered the stages of clinical development. On the other hand, further improvement of inhaled drug delivery could be an interesting possibility because it targets the organ of interest directly, requires significantly less drug to exert the pharmacological effect and, by lowering the amount of drug needed, reduces the cost of therapy. Unfortunately, however, the development of new inhaled drugs for use in COPD is currently too slow.
... An added benefit is that heparin is a well-known and widely used medication and its side effects have been studied in detail (see [42,43] and the references therein). This greatly facilitates the expansion of its scope; the general limitations for LMWH use remain valid in these cases as well. ...
Our objective is to reveal the molecular mechanism of the anti-inflammatory action of low-molecular-weight heparin (LMWH) based on its influence on the activity of two key cytokines, IFNγ and IL-6. The mechanism of heparin binding to IFNγ and IL-6 and the resulting inhibition of their activity were studied by means of extensive molecular-dynamics simulations. The effect of LMWH on IFNγ signalling inside stimulated WISH cells was investigated by measuring its antiproliferative activity and the translocation of phosphorylated STAT1 in the nucleus. We found that LMWH binds with high affinity to IFNγ and is able to fully inhibit the interaction with its cellular receptor. It also influences the biological activity of IL-6 by binding to either IL-6 or IL-6/IL-6Rα, thus preventing the formation of the IL-6/IL-6Rα/gp130 signalling complex. These findings shed light on the molecular mechanism of the anti-inflammatory action of LMWH and underpin its ability to influence favourably conditions characterised by overexpression of these two cytokines. Such conditions are not only associated with autoimmune diseases, but also with inflammatory processes, in particular with COVID-19. Our results put forward heparin as a promising means for the prevention and suppression of severe CRS and encourage further investigations on its applicability as an anti-inflammatory agent.
... Furthermore, Some researchers have demonstrated that lowmolecular-weight heparins (LMWH) have shown significant resistance to pro-angiogenesis and pro-thrombosis stimulation of the endothelium by different tumor cells, including APL cells (Vignoli et al., 2011(Vignoli et al., , 2017. For instance, In vitro and in vivo adhesion and infiltration of leukocytes can be inhibited by LMWH (Lever and Page, 2012) in one of these studies; dalteparin, while administered at exceptionally high concentration, i.e., 1000 IU/ml, affected the expression of ICAM-1 and E-selectin stimulated by cytokines on HUVEC. However, the concentration of drug used is beyond the therapeutic range (0.1-1 IU/ml) (Lever et al., 2000). ...
Low molecular weight heparin is a Heparin derivative, produced from commercial-grade Heparin through Chemical or enzymatic depolymerization. LMWH has remained a favored regimen for anticoagulation in cancer patients. Evidence from several studies has suggested that LMWHs possess antitumor and antimetastatic activity aside from their anticoagulant activity. Cancer metastasis is the foremost reason for cancer-related motility rate. Studies have pointed out that adhesion molecules play a decisive role in enhancing recurrent, invasive, and distant metastasis. Therefore, it is hypothesized that Cell adhesion molecules can be determined as a potential therapeutic target group, as antibodies or small-molecule inhibitors could easily access their extracellular domains. Furthermore, data from several investigations have reported LWMH potential effects as antimetastatic agents through influencing cell adhesion molecules. This review's objective is to emphasize the evidence available for the effects of the LMWHs in cell adhesion to inhibit tumor metastasis.
... [16][17][18][19] Heparin is a highly sulfated GAG that is used as anti-coagulant drug but exerts other biological activities such as anti-inflammatory, inhibiting leukocyte adhesion to endothelium and accumulation of cells in inflamed tissues by binding directly to several adhesion molecules expressed during inflammation. 13,[20][21][22] Due to its high affinity for large variety of cytokines and growth factors, it is also used as a carrier and as a component of drug delivery systems and scaffolds in tissue engineering. 23 In recent years potential benefits of blending hyaluronic acid with BCP were analyzed. ...
Biphasic calcium phosphate (BCP) materials are widely employed as bone substitute materials due to their resorption/degradation properties. Inflammation after implantation of such materials represents a prerequisite for bone tissue repair and regeneration but can be also problematic if it is not only transient and if it is followed by fibrosis and scarring. Here, we modified BCP covalently with hyaluronan (HA) and heparin (Hep), glycosaminoglycans that possess anti‐inflammatory properties. Beside the characterization of particle surface properties, the focus was on in vivo tissue response after subcutaneous implantation in mice. Histological analysis revealed a decrease in signs of inflammatory response to BCP when modified with either HA or Hep. Reduced vascularization after 30 days was noticed when BCP was modified with either HA or Hep with greater cellularity in all examined time points. Compared to plain BCP, expression of endothelial‐related genes Flt1 and Vcam1 was higher in BCP‐HA and BCP‐Hep group at day 30. Expression of osteogenesis‐related genes Sp7 and Bglap after 30 days was the highest in BCP group, followed by BCP‐Hep, while the lowest expression was in BCP‐HA group which correlates with collagen amount. Hence, coating of BCP particles with HA seems to suppress inflammatory response together with formation of new bone‐like tissue, while the presence of Hep delays the onset of inflammatory response but permits osteogenesis in this subcutaneous bone‐forming model. Transferring the results of this study to other coated materials intended for biomedical application may also pave the way to reduction of inflammation after their implantation.
... Apart from these direct antiviral properties, heparin is known to have anti-inflammatory activity via, among other mechanisms, its ability to neutralise a variety of cationic immune mediators including IL-6 and IL-8 and to inhibit chemotaxis. 35,36 In mammals, heparin is found in mast cells, suggesting its physiological usefulness in mucosal and connective tissue. Inhaled heparin has been used in patients with cystic fibrosis for its proposed mucolytic activity and a reduction of serum levels of IL-6 and IL-8 were observed. ...
Here, we advocate a highly favourable opportunity for the treatment of COVID-19 disease by repurposing a long-serving medical agent with an excellent history of clinical use, namely heparin. Heparin is best known as an anticoagulant, but it also exhibits direct antiviral activity against many enveloped viruses and has anti-inflammatory activity. The high incidence of thromboembolic events in COVID-19 patients suggests that coagulopathy plays an important role in the SARS-CoV-2 pathogenesis. This already makes heparin a unique, potentially curative agent that can be used immediately to help resolve the ongoing crisis associated with SARS-CoV-2 infection and COVID-19 disease. We demonstrate here in vitro that heparin does indeed inhibit SARS-CoV-2 infection. The three concurrent modes of activity of heparin (antiviral, anticoagulant and anti-inflammatory) against SARS-CoV-2/COVID-19 form a unique therapeutic combination. Thus, repurposing of heparin to fight SARS-CoV-2 and COVID-19 appears to be a powerful, readily available measure to address the current pandemic.
... There is interest in the role that heparin can play beyond acting as an anticoagulant and antithrombotic. A range of in vitro studies have demonstrated that heparin possesses beneficial antiinflammatory and anti-complement activity [1]. It is conceivable that the utilisation of heparin in many indications may not require its anticoagulant activity and this anticoagulant activity could be considered an undesirable feature in such settings [2]. ...
Cytotoxic and pro-inflammatory histones are present in neutrophil extracellular traps (NETs) and are elevated in blood in several inflammatory conditions, sepsis being a major example. Compounds which can attenuate activities of histones are therefore of interest, with heparin being one such material that has previously been shown to bind to histones. Heparin, a successful anticoagulant for nearly a century, has been shown experimentally to bind to histones and exhibit a protective effect in inflammatory conditions. In the present study carried out in whole blood, heparin and selectively desulfated heparin reduced histone induced inflammatory markers such as interleukin 6 (IL 6), interleukin 8 (IL 8) and tissue factor and C3a, a complement component. The selectively desulfated heparins, with reduced anticoagulant activities, retained a high degree of effectiveness as an anti-histone agent, whereas fully desulfated heparin was found to be ineffective. The results from this study indicate that the presence of sulfate and other specific structural features are required for heparin to attenuate the inflammatory action of histones in whole blood.
... Polysaccharides play an important role in immune regulation, and some of them are well-recognized anti-inflammatory molecules. The endogenous glycosaminoglycan (GAG) heparin bears many anti-inflammatory properties, which are not linked to the anti-coagulant activities of this molecule [76]. Compounds mirroring the anti-inflammatory activity of heparin, but deprived of its anti-coagulant effect, are potential new drug candidates. ...
The recent advances in cancer immunotherapy confirm the crucial role of the immune system in cancer progression and treatment. Chronic inflammation and reduced immune surveillance are both features of the tumor microenvironment. Strategies aimed at reverting pro-tumor inflammation and stimulating the antitumor immune components are being actively searched, and the anticancer effects of many candidate drugs have been linked to their ability to modulate the immune system. Marine organisms constitute a rich reservoir of new bioactive molecules; some of them have already been exploited for pharmaceutical use, whereas many others are undergoing clinical or preclinical investigations for the treatment of different diseases, including cancer. In this review, we will discuss the immune-modulatory properties of marine compounds for their potential use in cancer prevention and treatment and as possible tools in the context of cancer immunotherapy.
... [16][17][18][19] Heparin is a highly sulfated GAG that is used as anti-coagulant drug but exerts other biological activities such as anti-inflammatory, inhibiting leukocyte adhesion to endothelium and accumulation of cells in inflamed tissues by binding directly to several adhesion molecules expressed during inflammation. 13,[20][21][22] Due to its high affinity for large variety of cytokines and growth factors, it is also used as a carrier and as a component of drug delivery systems and scaffolds in tissue engineering. 23 In recent years potential benefits of blending hyaluronic acid with BCP were analyzed. ...
Inflammation and subsequent fibrotic encapsulation that occur after implantation of biomaterials are issues that fostered efforts in designing novel biocompatible materials to modulate the immune response. In this study, glycosaminoglycans (GAG) like hyaluronic acid (HA) and heparin (Hep) that possess anti‐inflammatory activity were covalently bound to NH2‐modified surfaces using EDC/NHS cross‐linking chemistry. Immobilization and physical surface properties were characterized by atomic forces microscopy, water contact angle studies and streaming potential measurements demonstrating the presence of GAG on the surfaces that became more hydrophilic and negatively charged compared to NH2‐modified. THP‐1 derived macrophages were used here to study the mechanism of action of GAG to affect the inflammatory responses illuminated by studying macrophage adhesion, the formation of multinucleated giant cells (MNGCs) and IL‐1β release that were reduced on GAG‐modified surfaces. Detailed investigation of the signal transduction processes related to macrophage activation was performed by immunofluorescence staining of NF‐κB (p65 subunit) together with immunoblotting. We studied also association and translocation of FITC‐labelled GAG. The results show a significant decrease in NF‐κB level as well as the ability of macrophages to associate with and take up HA and Hep. These results illustrate that the anti‐inflammatory activity of GAG is not only related to making surfaces more hydrophilic, but also their active involvement in signal transduction processes related to inflammatory reactions, which may pave the way to design new anti‐inflammatory surface coatings for implantable biomedical devices. This article is protected by copyright. All rights reserved.
... Furthermore, LMWH has the ability to regulate cellular apoptosis (Yu et al. 2008). LMWH reduces leucocyte recruitment at the site of injury or inflammatory stimuli through the downregulation of the expression of cytokines, tumour necrosis factor (TNF)-a, endotoxins, human leukocyte elastase (HLE), and heparinase (Lever and Page 2012). The administration of LMWH was shown to significantly decrease ND scores and mediate a neuroprotective effect against cerebral ischaemia-reperfusion injury through improvement in energy metabolism, inhibition of apoptosis, and attenuation of inflammatory responses (Zhang et al. 2013). ...
Context: The interruption of cerebral blood circulation may cause stroke characterized by high neurological deficits (NDs) as a result of neuronal dysfunction or destruction. Heparin may exert a neuroprotective effect against cerebral ischaemia/reperfusion injury.
Objective: The objective of this study was to investigate the mechanism underlying the effects of heparin pre-treatment on cerebral injury in the gerbil.
Materials and methods: A total of 80 healthy Mongolian gerbils were randomly divided into four groups to establish cerebral ischaemia model by bilateral carotid artery occlusion: control (no anaesthesia and surgery), sham (no occlusion), non-anticoagulation (occlusion), and anti-coagulation treatment groups (50 IU/100 g heparin pre-treated, occlusion). Gerbils were anesthetized with 40 mg/kg pentobarbital sodium through intraperitoneal injection before operation except for the control group. Then, the ND and histopathological damage (HD) scores were determined. The percentage of tumour necrosis factor (TNF)-α- and interleukin (IL)-1β-positive cells were calculated based on immunohistochemical results. The mRNA and protein levels of caspase-9, caspase-8, FasL, and calpain were evaluated with real-time polymerase chain reaction (RT-PCR) and western blotting, respectively.
Results: Compared with non-anticoagulation group, heparin pre-treatment (50 IU/100 g) delayed the onset of dyspnoea (p < 0.05), and showed a significant decrease in ND (p < 0.01), mortality rate (p < 0.05), HD (p < 0.01) and percentage of positive cells for TNF-α, IL-1β (p < 0.01) in cerebral ischaemia gerbils. Besides, the expression levels of caspase-9, caspase-8, FasL, and calpain were reduced after pre-treatment with 50 IU/100 g heparin.
Discussion and conclusions: The damage caused to gerbil brain was reduced upon pre-treatment with heparin, possibly through the amelioration of neuronal cell apoptosis and expression of TNF-α and IL-1β. These findings are expected to provide a new breakthrough in the study and treatment of cerebral ischaemia.
... The heparin-AT III complex also exhibits anti-inflammatory properties. 12 Enoxaparin is a low molecular weight heparin with a longer half-life in the blood than heparin. It functions as an anticoagulant that is administered via subcutaneous injection. ...
Purpose:
We used the juvenile rabbit as a model for investigating therapeutic interventions for postoperative inflammation and fibrin formation following intraocular lens (IOL) insertion for management of pediatric cataracts.
Methods:
Twelve 6- to 7-week-old, 600 to 900 g rabbits underwent bilateral clear-cornea lensectomy via irrigation and aspiration with IOL insertion. Following wound closure, enoxaparin 8 mg (n = 6 eyes), preservative-free triamcinolone 0.5 mg (n = 6), 8 mg enoxaparin plus 0.5 mg triamcinolone (n = 6), or balanced salt solution (n = 6) was injected into the anterior chamber. Slit-lamp examinations and optical coherence tomography (OCT) scans were performed postoperatively on days 3 through 7, and 14 to characterize levels of inflammation and fibrin. Using 17 additional rabbits, enzyme-linked immunosorbent assays (ELISAs) with 100 μL of aqueous humor were performed to quantify the amount of fibrinogen and fibrin preoperatively and on postoperative day 3. Immunohistochemistry was performed to confirm the presence of fibrin.
Results:
Enoxaparin alone and combined with triamcinolone reduced the amount of fibrin present in the anterior chamber compared to untreated eyes, which corresponded to an increase in OCT signal strength. Despite the clear visual axis shown in clinical images, the combination treatment group had the highest levels of soluble fibrin when assessed by ELISA. Immunohistochemistry confirmed the presence of insoluble fibrin seen clinically.
Conclusions:
A combination of enoxaparin and triamcinolone appears to provide the most therapeutic benefit by reducing fibrin formation and postoperative inflammation.
Translational relevance:
The juvenile rabbit is an excellent model to investigate inflammation and fibrin formation following lensectomy with IOL insertion and possibly any intraocular surgery in children.
... Because it is being used alongside multiple antithrombotic agents, clopidogrel is preferable to other P2Y12 inhibitors, such as ticagrelor or prasugrel (67). Enoxaparin is preferred for its rapid onset, reliable anticoagulation (unlike warfarin), and potential for anti-inflammatory properties (68). Some other providers may only use anticoagulants acutely for patients within six months of a diagnosed venous thromboembolism or known thrombophilia (69). ...
Iliocaval thrombosis, or thrombosis of the inferior vena cava and iliac veins, is associated with significant morbidity in the form of limb-threatening compromise from phlegmasia cerulean dolens, development of post-thrombotic syndrome, and death secondary to pulmonary embolism. Endovascular iliocaval reconstruction is an effective treatment for iliocaval thrombosis with high levels of technical success, favorable clinical outcomes and stent patency rates, and few complications. It is often able to relieve the debilitating symptoms experienced by affected patients and is a viable option for patients who fail conservative management. This article presents an approach to endovascular iliocaval stent reconstruction in patients suffering from chronic iliocaval thrombosis that takes into consideration background, patient selection and indications, timing of intervention, procedural steps, technical considerations, post-procedural care, and outcomes, along with providing schematic illustrations that serve to outline iliocaval stent reconstruction and management of chronic venous occlusions.
... Enoxaparin is chosen to ensure reliable anticoagulation (unlike warfarin) with a rapid onset and the potential for anti-inflammatory properties. 17 Given the use of multiple antithrombotic agents, clopidogrel is preferable to other P2Y12 inhibitor antiplatelet medications, such as prasugrel or ticagrelor. Other providers use anticoagulants acutely only for patients within 6 months of a diagnosed venous thromboembolism or known thrombophilia. ...
Thrombosis of the inferior vena cava and iliac veins, known as iliocaval thrombosis, is a common cause of significant morbidity. Patients with chronic iliocaval obstruction often present with life-limiting occlusive symptoms secondary to recurrent lower extremity deep venous thrombosis, swelling, pain, venous stasis ulcers, or phlegmasia. Endovascular iliocaval reconstruction is a technically successful procedure that results in favorable clinical outcomes and stent patency rates with few complications and is often able to relieve debilitating symptoms in affected patients. This review presents an approach to endovascular iliocaval stent reconstruction in patients suffering from chronic iliocaval thrombosis, including background, patient selection, timing of intervention, procedural steps, technical considerations, patient follow-up, and a brief review of outcomes. Schematic illustrations and clinical cases outlining iliocaval stent reconstruction and crossing chronic venous occlusions have been provid
... Interestingly, the patient's pain improved on anticoagulation despite imaging findings demonstrating no change in the size of the thrombus. There is evidence that heparin has anti-inflammatory properties that exist apart from its role in anticoagulation [28,29]. The action of mechanism is thought to involve the inhibition of mediators involved in inflammation [30]. ...
... [38][39][40] However, smaller trials have demonstrated that subcutaneous LMWH improved perinatal outcomes in thrombophilia 2 women with previous severe PE. 41 In addition, over recent years, the activity and functional role of NAC heparins in different forms have been widely investigated, including in angiogenesis and pulmonary diseases. [42][43][44] The antiinflammatory role, via inhibition of leukocyte infiltration, 45 and antimetastatic role in lung and colon 46 and pancreatic cancer cells 47 of these NAC heparins has also been established. However, their efficacy and safety in pregnancy have not been investigated. ...
Key Points
UFH, LMWH, and NAC restored angiogenesis in decorin-reduced endothelial cells. NAC treatment was similar to, or better than, UFH or LMWH at improving endothelial angiogenesis without increasing anticoagulant activity.
... While heparin's anticoagulant properties undoubtedly play a role in inflammatory physiology, a simple understanding of heparin as anticoagulant neglects heparin's broader role as a modulator of inflammatory function. Heparin and its derivative molecules possess significant anti-inflammatory activity[57]. Heparin and heparinoids exert their anti-inflammatory effects through a wide variety of mechanisms. At the level of signal transduction, they reduce LPS-induced nuclear translocation of NF-κβ and the associated inflammatory response both in vitro and in vivo, although mechanistic explanations of this phenomenon are lacking[58,59]. ...
Pharmacologic efforts to improve outcomes following aneurysmal subarachnoid hemorrhage (aSAH) remain disappointing, likely owing to the complex nature of post-hemorrhage brain injury. Previous work suggests that heparin, due to the multimodal nature of its actions, reduces the incidence of clinical vasospasm and delayed cerebral ischemia that accompany the disease. This narrative review examines how heparin may mitigate the non-vasospastic pathological aspects of aSAH, particularly those related to neuroinflammation. Following a brief review of early brain injury in aSAH and heparin’s general pharmacology, we discuss potential mechanistic roles of heparin therapy in treating post-aSAH inflammatory injury. These roles include reducing ischemia-reperfusion injury, preventing leukocyte extravasation, modulating phagocyte activation, countering oxidative stress, and correcting blood-brain barrier dysfunction. Following a discussion of evidence to support these mechanistic roles, we provide a brief discussion of potential complications of heparin usage in aSAH. Our review suggests that heparin’s use in aSAH is not only safe, but effectively addresses a number of pathologies initiated by aSAH.
... Non-anticoagulant effects of heparins have been described. 67 The potential of such actions is currently being investigated for the novel anticoagulants, further supporting our choice of anticoagulant in this study. 68 The clinical impact of this study is likely to be realised in the near term and the scope for cost-savings from reduced need for hospitalisations is considerable. ...
Introduction
Systemic sclerosis (SSc) is a severe and costly multiorgan autoimmune connective tissue disease characterised by vasculopathy and fibrosis. One of the major causes of SSc-related death is pulmonary arterial hypertension (PAH), which develops in 12–15% of patients with SSc and accounts for 30–40% of deaths. In situ thrombosis in the small calibre peripheral pulmonary vessels resulting from endothelial dysfunction and an imbalance of anticoagulant and prothrombotic mediators has been implicated in the complex pathophysiology of SSc-related PAH (SSc-PAH), with international clinical guidelines recommending the use of anticoagulants for some types of PAH, such as idiopathic PAH. However, anticoagulation has not become part of standard clinical care for patients with SSc-PAH as only observational evidence exists to support its use. Therefore, we present the rationale and methodology of a phase III randomised controlled trial (RCT) to evaluate the efficacy, safety and cost-effectiveness of anticoagulation in SSc-PAH.
Methods and analysis
This Australian multicentre RCT will compare 2.5 mg apixaban with placebo, in parallel treatment groups randomised in a 1:1 ratio, both administered twice daily for 3 years as adjunct therapy to stable oral PAH therapy. The composite primary outcome measure will be the time to death or clinical worsening of PAH. Secondary outcomes will include functional capacity, health-related quality of life measures and adverse events. A cost-effectiveness analysis of anticoagulation versus placebo will also be undertaken.
Ethics and dissemination
Ethical approval for this RCT has been granted by the Human Research Ethics Committees of all participating centres. An independent data safety monitoring board will review safety and tolerability data for the duration of the trial. The findings of this RCT are to be published in open access journals.
Trial registration number
ACTRN12614000418673, Pre-results.
... Whilst much is now known about the nature of commercially prepared pharmaceutical heparin, both in its unfractionated and low-molecular weight forms, with respect to structure, biological activity and clinical effects [2e4], the physiological role of endogenous heparin is considerably less well understood. It has long been known, however, that heparin possesses additional effects that are both separate to, and separable from, its well-characterized effects on blood coagulation, many of which involve modulation of aspects of immune or inflammatory cell function [5,6]. In contrast to the closely related GAG heparan sulphate, the ubiquitous expression of which alone goes some way towards explaining its pivotal role in normal physiology [7,8], mammalian heparin is produced exclusively by mast cells. ...
The properties of commercially prepared heparin as an anticoagulant and antithrombotic agent in medicine are better understood than is the physiological role of heparin in its native form, where it is uniquely found in the secretory granules of mast cells. In the present study we have isolated and characterised the glycosaminoglycans (GAGs) released from degranulating rat peritoneal mast cells. Analysis of the GAGs by NMR spectroscopy showed the presence of both heparin and the galactosaminoglycan dermatan sulphate; heparinase digestion profiles and measurements of anticoagulant activity were consistent with this finding. The rat peritoneal mast cell GAGs significantly inhibited accumulation of leukocytes in the rat peritoneal cavity in response to IL-1β (p < 0.05, n = 6/group), and inhibited adhesion and diapedesis of leukocytes in the inflamed rat cremasteric microcirculation in response to LPS (p < 0.001, n = 4/group). FTIR spectra of human umbilical vein endothelial cells (HUVECs) were altered by treatment of the cells with heparin degrading enzymes, and restored by the addition of exogenous heparin. In conclusion, we have shown that rat peritoneal mast cells contain a mixture of GAGs that possess anticoagulant and anti-inflammatory properties.
... Heparin exerts many of its nonanticoagulant actions through binding to the proteins such as chemokines and growth factors. However, exact mechanism of anti-inflammatory effect of heparin is not well known [28]. ...
Background:
Association between thrombosis pathogenesis and inflammatory conditions has been reported. Also inflammatory biomarkers have been proposed for prediction of thrombosis events.
Objectives:
Effects of different methods of heparin administration (subcutaneous vs continuous infusion) as thromboprophylaxis on the biomarkers of thrombosis have been evaluated.
Methods:
Serum levels of hsCRP, IL-10 and P-selectin as the biomarkers of thrombosis were measured at baseline, days 3 and 7 during the patients' hospitalization period.
Results:
Changes in the serum levels of thrombosis biomarkers (hsCRP, IL-10 and P-selectin) were comparable between the subcutaneous and continuous infusion groups.
Conclusion:
Both subcutaneous injection and continuous infusion of heparin as thromboprophylaxis showed same effects on the thrombosis biomarkers.
... Heparin not only inhibits blood coagulation and thrombin formation, but also possesses multiple nonanticoagulant functions [110]. It suppresses the activation of a range of inflammatory cells by binding and neutralizing inflammatory mediators or enzymes released during inflammatory response. ...
Sepsis is the commonest cause of acute kidney injury in critically ill patients. Its pathophysiology is complex and not well understood. Until recently, it was believed that kidney hypoperfusion is the major contributor of septic acute kidney injury. However, recent publications have improved our understanding on this topic. We now know that its mechanisms included the following: (1) renal macrocirculatory and microcirculatory disturbance, (2) surge of inflammatory markers and oxidative stress, (3) coagulation cascade activation, and (4) bioenergetics adaptive response with controlled cell-cycle arrest aiming to prevent cell death. Uncovering these complicated mechanisms may facilitate the development of more appropriate therapeutic measures in the future.
... Specific non-anticoagulant effects have been ascribed to heparin as well. It downregulates the inflammatory response by binding immune-activating enzymes and inhibits adhesion of leukocytes to the endothelial wall [21]. Several animal studies and case reports also suggest a beneficial effect on wound healing and tissue repair [22]. ...
Glioblastoma multiforme (GBM) is the most common primary brain tumor that is invariably lethal. Novel treatments are desperately needed. In various cancers, heparin and its low molecular weight derivatives (LMWHs), commonly used for the prevention and treatment of thrombosis, have shown therapeutic potential. Here we systematically review preclinical and clinical studies of heparin and LMWHs as anti-tumor agents in GBM. Even though the number of studies is limited, there is suggestive evidence that heparin may have various effects on GBM. These effects include the inhibition of tumor growth and angiogenesis in vitro and in vivo, and the blocking of uptake of extracellular vesicles. However, heparin can also block the uptake of (potential) anti-tumor agents. Clinical studies suggest a non-significant trend of prolonged survival of LMWH treated GBM patients, with some evidence of increased major bleedings. Heparin mimetics lacking anticoagulant effect are therefore a potential alternative to heparin/LMWH and are discussed as well.
Electronic supplementary material
The online version of this article (doi:10.1007/s11060-015-1826-x) contains supplementary material, which is available to authorized users.
In December 2019, a new coronavirus which named SARS‐CoV‐2 (Severe Acute Respiratory Syndrome Coronavirus‐2) emerged from China, and during months, COVID‐19 spread in many countries around the world. Clinical manifestation spectrum associated with COVID‐19 is various and not completely clear. The disease presentations can range from an asymptomatic infection or mild illness to severe pneumonia, sepsis, loss of organs function, and even death. Although most people with COVID‐19 will face mild manifestations, some patients will demonstrate severe clinical signs that lead to hospitalization and intensive care unit (ICU) admission. These clinical complications include severe lung dysfunction, sepsis, shock, or multiple organ failure. Coagulation disorders and thrombotic complications were reported in COVID‐19 patients. The mechanism of Coagulation disorders is not precise in COVID‐19 patients. The current study tried to provide a comprehensive view of the pathophysiology, mechanisms, therapeutic approaches, and considerations about the coagulopathy during COVID‐19. image
The pathophysiological mechanism of abnormal coagulation can result from smoke inhalation injury (SII). Heparin nebulization is a common treatment for lung disorders. This study aimed to use meta-analysis in animal models to examine the effectiveness of atomized heparin on SII. For our online searches, we used the Cochrane Central Register of Controlled Trials, PubMed, Web of Science, Chinese National Knowledge Infrastructure, Chinese BioMedical Literature Database, and Wanfang Database up to January 2022. Data for SII were retrieved and compared to control animals. The studies’ findings were determined by combining standardized mean difference (SMD) analysis with 95% confidence intervals (CIs). The findings showed that as compared to the control group, the heparin-treated group had a lower death rate (relative risk 0.42; 95% CI 0.22, 0.80; p < .05). The meta-analysis demonstrated favorable changes in lung physiology, including PaO2/FiO2 (SMD 1.04; 95% CI 0.65, 1.44; p < .001), lung wet-to-dry weight ratio (SMD −1.83; 95% CI −2.47, −1.18; p < .001), and pulmonary shunt Qs/Qt (SMD −0.69; 95% CI −1.29, −0.08; p < .05) after heparin nebulization for lung injury. The present data indicated that pulmonary artery mean pressure in the heparin therapy group was significantly lowered after 24 and 48 hours of therapy, suggesting that the cardiovascular system could recover following heparin treatment. As a result, heparin nebulization appeared to be more effective against SII and improved cardiopulmonary function compared to the control group.
Graphical Abstract
Low-molecular-weight heparins (LMWHs) are used in clinical practice as anticoagulants since they enhance the antithrombin III (ATIII) inhibitory action against coagulation enzymes.
This work is focused on the effects on ATIII protein induced by the interaction with LMWHs. In particular, the ATIII thermal stability modifications in the presence of Dalteparin, Enoxaparin and Tinzaparin and their fractionated portions were investigated. Furthermore, the effects of standard heparin and of a synthetic pentasaccharide, namely an α-methylated structural analogue of the ATIII-binding sequence (AGA*IAM), were also assessed.
Our results highlight the main contributions concurring at the variation of ATIII thermodynamic properties in the presence of LMWHs, indicating that the thermal stability of the protein mainly depends on the effective [AGA*IA]/[protein] ratio regardless the overall chain peculiarities.
The COVID-19 pandemic is caused by aerosol transmission of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). The disease primarily causes pneumonia of varying severity resulting in respiratory failure. COVID-19 pneumonia patients require prolonged hospitalization and often critical care support including mechanical ventilation. Despite extensive research, current formulations and dose regimens of systemic therapeutics assessed for use in COVID-19 are either associated with adverse effects or are ineffective, which in part might be explained by inadequate lung penetration. Consequently, COVID-19 pneumonia is associated with high morbidity and mortality. Despite effective vaccine development, the disease is likely to remain prevalent due to logistics and viral mutations. Hence, there is an urgent need for safe and effective COVID-19 therapies. Nebulized drug delivery of existing formulations could potentially achieve higher local drug concentrations and improve clinical outcomes with limited systemic adverse effects. Various nebulized therapeutic agents are currently undergoing clinical trials. Barriers affecting safe and effective nebulized therapies should be addressed simultaneously to provide guidelines for nebulized therapeutics for COVID-19 pneumonia in critical care. We review the technical aspects of nebulization therapy and consider which medications are likely to be most suitable for delivery by this route.KeywordsCOVID-19Viral pneumoniaNebulizersInhalationAerosols
Since artificial intelligence (AI) and, more specifically, machine learning have found their way into medical research, expectation for these techniques to advance patient care has been high. These hopes are also present in the infection management field, where an ongoing need exists to ameliorate antimicrobial usage for the benefit of the patient and society. As machine readable data generation is among the highest in the intensive care unit (ICU), studies into these new techniques to support antimicrobial stewardship have been frequent. Although research output has never been greater, incorporation of developed models into clinical practice has been scarce. With this manuscript, we aim to provide the reader an overview of the current stance of AI/machine learning research in different areas of antimicrobial stewardship in the ICU, the barriers that hinder clinical adaptation, and pitfalls for bedside use by using the antimicrobial stewardship cycle as a framework.KeywordsAntimicrobial stewardshipIntensive care unitArtificial intelligenceMachine learning
In this chapter, we describe an original protocol based on ITC experiments and data analysis with the software AFFINImeter to get information of heparin-AT interactions relevant for the elucidation of the anticoagulant activity of heparins. This protocol is used to confirm the presence of the bioactive pentasaccharide with anticoagulant activity in heparins and to determine the amount of this pentasaccharide in the sample. Here we have applied this protocol to the characterization of low molecular weight heparins.
Identifying structural elements within heparin (as well as other glycosaminoglycan) chains that enable their interaction with a specific client protein remains a challenging task due to the high degree of both intra- and inter-chain heterogeneity exhibited by this polysaccharide. The new experimental approach explored in this work is based on the assumption that the heparin chain segments bound to the protein surface will be less prone to collision-induced dissociation (CID) in the gas phase compared to the chain regions that are not involved in binding. Facile removal of the unbound chain segments from the protein/heparin complex should allow the length and the number of sulfate groups within the protein-binding segment of the heparin chain to be determined by measuring the mass of the truncated heparin chain that remains bound to the protein. Conformational integrity of the heparin-binding interface on the protein surface in the course of CID is ensured by monitoring the evolution of collisional cross-section (CCS) of the protein/heparin complexes as a function of collisional energy. A dramatic increase in CCS signals the occurrence of large-scale conformational changes within the protein and identifies the energy threshold, beyond which relevant information on the protein-binding segments of heparin chains is unlikely to be obtained. Testing this approach using a 1:1 complex formed by a recombinant form of an acidic fibroblast growth factor (FGF-1) and a synthetic pentasaccharide GlcNS,6S‐GlcA‐GlcNS,3S,6S‐IdoA2S‐GlcNS,6S‐Me as a model system indicated that a tri-saccharide fragment is the minimal-length FGF-binding segment. Extension of this approach to a decameric heparin chain (dp10) allowed meaningful binding data to be obtained for a 1:1 protein/dp10 complex, while the ions representing the higher stoichiometry complex (2:1) underwent dissociation via asymmetric charge partitioning without generating truncated heparin chains that remain bound to the protein.
Purpose: To evaluate the efficacy of heparin eye drops in the treatment of paraquat-induced ocular surface injury.
Design and methods: In this retrospective study, we included 25 patients (31 eyes) with paraquat-induced ocular surface injury, who attended the Affiliated Hospital of Weifang Medical University between October 2008 and October 2013. The patients were split into two groups according to whether or not received heparin eye drops. The clinical data were compared between the two groups, i.e., clinical histories, results of examinations, treatments and outcomes.
Results: Eleven patients (Group A, 15 eyes) received prompt irrigation with 0.9% saline every two hours, 0.1% pranoprofen eye drops four times a day, 20% autologous serum every two hours, recombinant bovine basic fibroblast growth factor eye-gel two times a day, oral vitamin C 2.0g and prednisone 30mg daily. Fourteen patients (Group B, 16 eyes) received additional treatment with heparin eye drops. Ten eyes in group A and seven eyes in group B developed a pseudomembrane on the ocular surface at significantly different rate (mean ± SD) of 1.20 ± 1.01 and 0.43 ± 0.51, respectively (t = 2.66, p = 0.01). 7 eyes among 10 had a pseudomembrane reoccurred in group A while none had a pseudomembrane reoccurred in group B. (Fisher’s exact test, p = 0.01) .No significant differences were seen in the duration of epithelial recovery between the two groups: 15.13 ± 5.13 days in group A and 16.81 ± 5.56 days in group B (t = 0.87, p = 0.39). After the treatment, mild corneal opacity and pannus were observed in five patients of group A and four patients of group B, without any significant difference between the two groups (p = 0.70).
Conclusions: The paraquat-induced ocular surface injury observed in this case series was characterized by the formation of conjunctival pseudomembrane with good prognosis and mild complications. Heparin eye drops reduce the occurrence, especially the reoccurrence of pseudomembrane. Further studies are warranted.
Fucose-containing sulfated polysaccharides (fucoidans) from brown algae exhibit anti-inflammatory activity in vivo, however, there is only limited knowledge about their mode of action. Potential targets may be the chemokine interleukin 8 (IL-8) and the anaphylatoxin C5a, as they are closely linked to inflammatory processes. In this study, two fucoidans from Saccharina latissima and Fucus vesiculosus, and unfractionated heparin (UFH) were examined for their binding properties to IL-8 and C5a and their effects on IL-8- and C5a-induced reactions of polymorphonuclear neutrophils (PMN).
As proved by a competitive sulfated polysaccharide-coating-ELISA, both fucoidans bind to IL-8 and C5a, whereby they showed higher affinity to IL-8. Whereas UFH displayed only moderate effects, the fucoidans concentration-dependently reduced the IL-8- and C5a-induced intracellular calcium release, Erk1/2 phosphorylation and chemotaxis of PMN. Their inhibitory potency is dependent on the target protein, but also other aspects than the binding turned out to play a role.
Purpose of review:
This article provides an update on hypersensitivity reactions to heparins and novel oral anticoagulants, with special emphasis on diagnostic methods and management of patients.
Recent findings:
Although heparins are drugs widely used, hypersensitivity reactions are uncommon. Cutaneous delayed hypersensitivity reactions after subcutaneous administration affects up to 7.5% of patients. Heparin-induced thrombocytopenia is another unusual but severe condition in which early recognition is crucial. Immediate hypersensitivity reactions to heparins have been also reported, but with the novel oral anticoagulants are much more uncommon, although reports of exanthemas have been notified.Skin tests and subcutaneous provocation test are useful tools in the diagnosis of hypersensitivity reactions, except in heparin-induced thrombocytopenia in which biopsy of lesional skin and in-vitro tests are the modalities of choice to confirm the diagnosis.Management of hypersensitivity reactions includes finding an alternative depending on the type of reaction. Fondaparinux and novel oral anticoagulants may be safe alternatives.
Summary:
Delayed skin lesions after subcutaneous heparin are the most common type of hypersensitivity reactions, followed by life-threatening heparin-induced thrombocytopenia. Immediate reactions are uncommon. Allergologic studies may be useful to find an alternative option in patients with skin lesions in which heparin-induced thrombocytopenia has been previously excluded, as well as in heparin immediate reactions.
The aim of this chapter is to provide an overview of non-anticoagulant effects of heparins and their potential use in new therapeutic applications. Heparin and heparin derivatives have been tested in inflammatory, pulmonary and reproductive diseases, in cardiovascular, nephro- and neuro-tissue protection and repair, but also as agents against angiogenesis, atheroschlerosis, metastasis, protozoa and viruses. Targeting and inhibition of specific mediators involved in the inflammatory process, promoting some of the above mentioned pathologies, are reported along with recent studies of heparin conjugates and oral delivery systems. Some reports from the institute of the authors, such as those devoted to glycol-split heparins are also included. Among the members and derivatives of this class, several are undergoing clinical trials as antimetastatic and antimalarial agents and for the treatment of labour pain and severe hereditary anaemia. Other heparins, whose therapeutic targets are non-anticoagulant such as nephropathies, retinopathies and cystic fibrosis are also under investigation.
On the centenary of the discovery of heparin, the International Journal of Cardiology agreed to publish a collection of mini reviews that summarize the historical development of this ever-young life-saving drug. The present articles deal not only with the historical milestones, but also with current and future perspectives regarding the development of heparin in terms of its structure, as well as on-going biochemical, biological and clinical research. Attention is focused on recent applications of heparin derivatives to non-anticoagulant or antithrombotic therapies, providing particular emphasis on their inhibitory activities, including their potential as anti-cancer agents. In the Chapter, entitled ‘Recent innovations in the structural analysis of heparin’, some recent technological advances are described for the problem of monitoring the purity and reproducibility of pharmaceutical heparin. These now permit sensitive detection of non-heparin impurities, as well as the detection of heparin from different animal sources, to be made in pharmaceutical heparin samples. In ‘Past, present, and future perspectives of heparin in clinical settings and the role of impaired renal function’, the author traces the history of heparin and the development of low molecular weight heparin, highlighting the large number of clinical trials in which it has been involved, and reviewing its efficacy among patients with impaired renal function. In the final chapter, ‘Old and new applications of non-anticoagulant heparin’, the authors survey some of the many non-anticoagulant activities of heparin and its derivatives, including glycol-split heparin, which has demonstrated promising activities in a wide-range of situations.
Heparin and related members of the glycosaminoglycan (GAG) family are highly polyanionic linear saccharadies that play important roles in a variety of physiological processes ranging from blood coagulation to embryo- and oncogenesis, tissue regeneration, and immune response regulation. These diverse functions are executed via a variety of mechanisms, including protein sequestration, activation and facilitating their interactions with cell-surface receptors, but deciphering the specific molecular mechanisms is frequently impossible due to the extremely high degree of GAG heterogeneity. As a result, the vast majority of studies of heparin (or related GAGs) interactions with its client proteins use synthetically produced heparin mimetics with defined structure or short heparin fragments. In this work we use native electrospray ionization mass spectrometry (ESI MS) in combination with limited charge reduction in the gas phase to obtain meaningful information on non-covalent complexes formed by intact unfractionated heparin and antithrombin-III, interaction which is central to preventing blood clotting. Complexes of different stoichiometries are observed ranging from 1:1 to 1:3 (heparin/protein ratio). In addition to binding stoichiometry, the measurements allow the range of heparin chain lengths to be obtained for each complex and the contribution of each complex to the total ionic signal to be calculated. Incorporation of ion mobility measurements in the experimental workflow allows the total analysis time to be shortened very significantly and the charge state assignment for the charge-reduced species to be verified. The possibility to study interactions of intact unfractionated heparin with a client protein carried out directly by native ESI MS without the need to use relatively homogeneous surrogates demonstrated in this work opens up a host of new exciting opportunities and goes a long way towards ameliorating the persistent but outdated view of the intractability of such interactions.
Acetaminophen (APAP)-induced liver injury in humans is associated with robust coagulation cascade activation and thrombocytopenia. However, it is not known whether coagulation-driven platelet activation participates in APAP hepatotoxicity. Here, we found that APAP overdose in mice caused liver damage accompanied by significant thrombocytopenia and accumulation of platelets in the liver. These changes were attenuated by administration of the direct thrombin inhibitor lepirudin. Platelet depletion with an anti-CD41 antibody also significantly reduced APAP-mediated liver injury and thrombin generation, indicated by the concentration of thrombin-antithrombin (TAT) complexes in plasma. Compared to APAP-treated wild-type mice, biomarkers of hepatocyte and endothelial damage as well as plasma TAT concentration and hepatic platelet accumulation were reduced in mice lacking protease activated receptor (PAR)-4, which mediates thrombin signaling in mouse platelets. However, selective hematopoietic cell PAR-4 deficiency did not affect APAP-induced liver injury or plasma TAT levels. These results suggest that interconnections between coagulation and hepatic platelet accumulation promote APAP-induced liver injury independent of platelet PAR-4 signaling. Moreover, the results highlight a potential contribution of non-hematopoietic cell PAR-4 signaling to APAP hepatotoxicity.
Copyright © 2015 American Society of Hematology.
The platelet-endothelial cell adhesion molecule-1 (PE-CAM-1), defined by the CD31 monoclonal antibody (MoAb), was initially described as a cell-cell adhesion molecule mediating both homotypic and heterotypic adhesion. In this report, we show that enriched CD34+ human hematopoietic progenitor cell populations, containing early myeloid, erythroid, and multipotential progenitor cells, are CD31+. Analyses of CD34+ cell lines representing early myeloid, multipotential, and pre- pre-B-lymphoid progenitors indicate that precursors of both myeloid and B-lymphoid cells express PECAM-1 at high levels. Three-color flow- cytometric analyses also show that normal human bone marrow CD31+ CD34+ subsets coexpress myeloid (CD33) or B-lymphoid (CD19, CD10) markers. Except for the monocytic cell line, U937, all CD34- cell lines tested, which represent more mature stages of the myeloid, erythroid, and lymphoid lineages, expressed substantially lower or negligible levels of PECAM-1. Western blotting studies indicated that the CD31 MoAb, JC/70A, detected molecules in the 120- to 140-kD molecular weight range on the monocytic CD34- CD33+ CD31+ cell line, U937; on the CD34+ CD31+ CD33+ CD19- multipotential/lymphomyeloid precursor cell lines, KG1 and KG1B; on the CD34+ CD31+ CD19+ CD10+ CD33- precursor pre-pre-B-cell line, MIK-ALL; and on a CD34(+)-enriched precursor cell population from normal human bone marrow. A single molecular weight species was generally observed with enriched membrane preparations, whereas two PECAM-1 molecules were present in whole-cell lysates of cell lines and the CD34+ bone marrow cell subset. Preliminary studies show that a proportion of the PECAM-1 molecules on the lymphomyeloid/multipotential progenitor cell line, KG1, and on the monocytic cell line, U937, binds to heparin-sepharose. A soluble form of PECAM-1 also binds heparin- sepharose. The high level of expression of PECAM-1 on CD34+ cells suggests that this glycoprotein may function as a heterotypic adhesion molecule, possibly mediating multipotential, myeloid, and early-B- lymphoid precursor cell interactions with stromal cells and extracellular matrix molecules via heparan sulfate proteoglycans. It may also act as a homotypic adhesion molecule by interacting with PECAM- 1 on bone marrow stromal macrophage-like cells and endothelial cells or on endothelial cells during stem/progenitor cell migration. Thus, this molecule has the potential importance of directing both lineage commitment and trafficking of early hematopoietic progenitor cells.
Tissue factor (TF) plays a crucial role in the pathogenesis of thrombotic, vascular, and inflammatory disorders, and thus, the inhibition of this membrane protein provides a unique therapeutic approach for prophylaxis and/or treatment of various diseases. In recent years, tissue-factor pathway inhibitor (TFPI), the only endogenous inhibitor of the TF/FVIIa complex, has been characterized biochemically and pharmacologically. Studies in patients have demonstrated that both TF and TFPI may be indicators for the course and the outcome of cardiovascular and other diseases. Based on experimental and clinical data, TFPI may become an important drug for several clinical indications. TFPI is expected to inhibit the development of postinjury intimal hyperplasia and thrombotic occlusion in atherosclerotic vessels, and to be effective in acute coronary syndromes (ACS) such as unstable angina (UA) and myocardial infarction (MI). Of special interest is the inhibition of TF-mediated processes in sepsis and disseminated intravascular coagulation, which are associated with the activation of various inflammatory pathways as well as the coagulation system. A phase II trial of the efficacy of TFPI in patients with severe sepsis showed a mortality reduction in TFPI- compared to placebo-treated patients and an improvement of organ dysfunctions. TFPI can be administered exogenously in high doses to suppress TF-mediated effects, or high amounts of TFPI can be released from intravascular stores by other drugs such as heparin and low molecular weight heparins (LMWHs). In this way, high concentrations of the inhibitor are provided at sites of tissue damage and ongoing thrombosis. At present clinical studies with TFPI are rather limited, and the clinical potential of the drug cannot be evaluated properly. However, TFPI and its variants are expected to undergo further development and to find indications in various clinical states.
The control of smooth muscle cell (SMC) proliferation is determined by the combined actions of mitogens, such as platelet-derived growth factor, and the opposing action of growth inhibitory agents, such as heparin and transforming growth factor-beta (TGF-beta). The present studies identify an interaction between heparin and TGF-beta in which heparin potentiates the biological action of TGF-beta. Using a neutralizing antibody to TGF-beta, we observed that the short term antiproliferative effect of heparin depended upon the presence of biologically active TGF-beta. This effect was observed in rat and bovine aortic SMC and in CCL64 cells, but not in human saphenous vein SMC. Binding studies demonstrated that the addition of heparin (100 micrograms/ml) to medium containing 10% plasma-derived serum resulted in a 45% increase in the specific binding of 125I-TGF-beta to cells. Likewise, heparin induced a twofold increase in the growth inhibitory action of TGF-beta at concentrations of TGF-beta near its apparent dissociation constant. Using 125I-labeled TGF-beta, we demonstrated that TGF-beta complexes with the plasma component alpha 2-macroglobulin, but not with fibronectin. Heparin increases the electrophoretic mobility of TGF-beta apparently by freeing TGF-beta from its complex with alpha 2-macroglobulin. Dextran sulfate, another highly charged antiproliferative molecule, but not chondroitin sulfate or dermatan sulfate, similarly modified TGF-beta's mobility. Relatively high, antiproliferative concentrations of heparin (1-100 micrograms/ml) were required to dissociate the TGF-beta/alpha 2-macroglobulin complex. Thus, it appears that the antiproliferative effect of heparin may be partially attributed to its ability to potentiate the biological activity of TGF-beta by dissociating it from alpha 2-macroglobulin, which normally renders it inactive. We suggest that heparin-like agents may be important regulators of TGF-beta's biological activity.
This study examines the role of L-selectin in monocyte adhesion to arterial endothelium, a key pathogenic event of atherosclerosis.
Using a nonstatic (rotation) adhesion assay, we observed that monocyte binding to bovine aortic endothelium at 4°C increased
four to nine times upon endothelium activation with tumor necrosis factor (TNF)-α. mAb-blocking experiments demonstrated
that L-selectin mediates a major part (64 ± 18%) of monocyte attachment. Videomicroscopy experiments performed under flow
indicated that monocytes abruptly halted on 8-h TNF-α–activated aortic endothelium, ∼80% of monocyte attachment being mediated
by L-selectin. Flow cytometric studies with a L-selectin/IgM heavy chain chimeric protein showed calcium-dependent L-selectin
binding to cytokine-activated and, unexpectedly, unactivated aortic cells. Soluble L-selectin binding was completely inhibited
by anti–L-selectin mAb or by aortic cell exposure to trypsin. Experiments with cycloheximide, chlorate, or neuraminidase
showed that protein synthesis and sulfate groups, but not sialic acid residues, were essential for L-selectin counterreceptor
function. Moreover, heparin lyases partially inhibited soluble L-selectin binding to cytokine-activated aortic cells, whereas
a stronger inhibition was seen with unstimulated endothelial cells, suggesting that cytokine activation could induce the
expression of additional ligand(s) for L-selectin, distinct from heparan sulfate proteoglycans. Under flow, endothelial
cell treatment with heparinase inhibited by ∼80% monocyte attachment to TNF-α–activated aortic endothelium, indicating a
major role for heparan sulfate proteoglycans in monocyte–endothelial interactions. Thus, L-selectin mediates monocyte attachment
to activated aortic endothelium, and heparan sulfate proteoglycans serve as arterial ligands for monocyte L-selectin.
Fibrin deposits surrounding circulating tumor cells may protect them from mechanical trauma and destruction by the host immune system, and may facilitate microvascular entrapment required for metastasis. We report that heparin inhibited the clotting of plasma induced by mouse mammary carcinoma cells in a dose-dependent manner and blocked the production of experimental lung metastasis when administered i.p. at the time of intravenous injection of tumor cells. On the other hand, O/N-desulfated N-acetylated heparin did not exhibit anticoagulant properties and had no effects on metastasis formation. Similarly, reduction of metastasis was not seen with N-desulfated N-acetylated heparin, another chemically modified heparin which does not inhibit blood coagulation but has heparanase inhibitory activity. Our data demonstrate the existence of a strong association between antimetastatic and anticoagulant properties of heparin species in the present experimental system.
Aneurysmal subarachnoid hemorrhage (SAH) is associated with numerous "delayed neurological deficits" (DNDs) that have been attributed to multiple pathophysiological mechanisms, including ischemia, microthrombosis, free radical damage, inflammation, and vascular remodeling. To date, effective prophylactic therapy for SAH-induced DNDs has been elusive, due perhaps to the multiplicity of mechanisms involved that render typical, single-agent therapy seemingly futile. We hypothesized that heparin, which has multiple underappreciated salutary effects, might be useful as a multitargeted prophylactic agent against SAH-induced DNDs. We performed a comprehensive review of the literature to evaluate the potential utility of heparin in targeting the multiple pathophysiological mechanisms that have been identified as contributing to SAH-induced DNDs. Our literature review revealed that unfractionated heparin can potentially antagonize essentially all of the pathophysiological mechanisms known to be activated following SAH. Heparin binds >100 proteins, including plasma proteins, proteins released from platelets, cytokines, and chemokines. Also, heparin complexes with oxyhemoglobin, blocks the activity of free radicals including reactive oxygen species, antagonizes endothelin-mediated vasoconstriction, smooth muscle depolarization, and inflammatory, growth and fibrogenic responses. Our review suggests that the use of prophylactic heparin following SAH may warrant formal study.
Heparin-binding EGF-like growth factor (HB-EGF) is a ligand for EGF receptor (EGFR) and possesses the ability to signal in juxtacrine, autocrine and/or paracrine mode, with these alternatives being governed by the degree of proteolytic release of the ligand. Although the spatial range of diffusion of released HB-EGF is restricted by binding heparan-sulfate proteoglycans (HSPGs) in the extracellular matrix and/or cellular glycocalyx, ascertaining mechanisms governing non-released HB-EGF localization is also important for understanding its effects. We have employed a new method for independently tracking the localization of the extracellular EGF-like domain of HB-EGF and the cytoplasmic C-terminus. A striking observation was the absence of the HB-EGF transmembrane pro-form from the leading edge of COS-7 cells in a wound-closure assay; instead, this protein localized in regions of cell-cell contact. A battery of detailed experiments found that this localization derives from a trans interaction between extracellular HSPGs and the HB-EGF heparin-binding domain, and that disruption of this interaction leads to increased release of soluble ligand and a switch in cell phenotype from juxtacrine-induced growth inhibition to autocrine-induced proliferation. Our results indicate that extracellular HSPGs serve to sequester the transmembrane pro-form of HB-EGF at the point of cell-cell contact, and that this plays a role in governing the balance between juxtacrine versus autocrine and paracrine signaling.
Since heparin possesses anti-inflammatory properties, it is hypothesised that asthmatic patients have decreased levels of circulating heparin compared with healthy individuals.
We compared endogenous heparin levels in controlled asthmatic patients (53 adults) from the Asthma Clinic at Johannesburg General Hospital with those of healthy controls (26 adults) from the general population. Heparin levels in the blood samples were tested using the Chromogenix Coatest Heparin kit.
The blood of the patients contained significantly lower levels of endogenous heparin compared with that of the healthy individuals, indicating that the anti-inflammatory properties afforded by heparin are absent in these patients.
Pulmonary injury from smoke inhalation is common in burn victims, significantly contributing to the morbidity and mortality of fire-related injuries. The impacts of improvement in other aspects of burn care have not been mirrored in treatment of smoke inhalation. Smoke is heterogeneous and unique to each fire; it comprises particulates, respiratory irritants and systemic toxins as well as heat, all contributing to the pathological insult. Thermal injury below the vocal cords is rare because of effective heat dissipation in the upper airway. Particulate matter is the chief contributor to the pathophysiology of smoke inhalation injury, which has been extensively described. Of paramount importance is the cascade of inflammatory mediators following interaction of irritant substances with lung parenchyma, leading to pulmonary oedema, cast formation, airway obstruction, loss of hypoxic pulmonary vasoconstriction and ventilation/perfusion mismatch. Current treatment is based on supportive care, with airway management, mechanical ventilation, humidification and aggressive airway toilet the mainstays. Nebulisation of n2-agonists, heparin and N-acetylcysteine have a role in management, as does more specific treatment of carbon monoxide or cyanide intoxication. Many promising treatments are currently under investigation. The therapeutic strategy of decontaminating the lungs early after smoke exposure to prevent inhalation injury has received little attention and may be of significant value. This could potentially utilise amphoteric, hypertonic chelating agents developed for topical and ocular chemical exposures.
Currently low molecular weight heparin (LMWH) is administered as subcutaneous injection. This study sought to investigate the feasibility of LMWH as an inhalable dry powder (DPI) formulation and evaluate the interaction of the drug with lactose when used as a carrier. The study also compares the extent of pulmonary absorption of LMWH administered as a dry powder with that administered as an aerosolized aqueous solution.
The formulations were prepared by mixing LMWH in an aqueous solution of lactose followed by lyophilization of the resulting solution. The lyophilized preparation was then ground and sieved. Physical characterization of the formulations was performed by Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), particle size analysis, and determination of aerodynamic diameter. For in vivo studies, formulations were administered to anesthetized rats, and drug absorption was monitored by measuring plasma antifactor Xa activity.
In the FTIR scan, all characteristic peaks of lactose and LMWH were observed, suggesting that there was no strong interaction between lactose and LMWH. Although the aerodynamic diameter of the formulation (DPI-2) that was sieved through 170- and 230-mesh screens was similar to that of the formulation (DPI-1) sieved through 120- and 170-mesh screens, the particle sizes of the two formulations were significantly different. Dry powder formulations of LMWH were better absorbed compared to an inhalable solution of LMWH. One of the dry powder formulations (DPI-2) produced an almost 1.5-fold increase in the relative bioavailability (41.6%) compared to the liquid formulation of LMWH (32.5%). Overall, the data presented here suggest that lactose does not adversely affect the physical-chemical characteristics of the drug, and that lactose can be used as a carrier for pulmonary delivery of LMWH.
Dysregulation of coagulation and local fibrinolysis found in patients with acute lung injury often results in the need for the support of mechanical ventilation. High-tidal-volume mechanical ventilation can increase lung damage and suppression of fibrinolytic activity, but the mechanisms are unclear. We hypothesized that subcutaneous injections of unfractionated heparin and enoxaparin would decrease neutrophil infiltration, lung edema, and plasminogen-activator inhibitor-1 (PAI-1) production in mice exposed to high-tidal-volume ventilation.
Male C57BL/6 mice, weighing 20 to 25 g, were exposed to either high-tidal-volume (30 ml/kg) or low-tidal-volume (6 ml/kg) mechanical ventilation with room air for 1 to 5 hours after 200 IU/kg or 400 IU/kg unfractionated heparin and 4 mg/kg or 8 mg/kg enoxaparin administration. Nonventilated mice served as a control group. Evan blue dye, lung wet- to dry-weight ratio, histopathologic grading of epithelium, myeloperoxidase, and gene expression of PAI-1 were measured. The expression of PAI-1 was studied by immunohistochemistry.
High-tidal-volume ventilation induced increased microvascular permeability, neutrophil influx, PAI-1 mRNA expression, production of PAI-1 protein, and positive staining of PAI-1 in epithelium in a dose-dependent manner. Lung injury induced by high-tidal-volume ventilation was attenuated with PAI-1-deficient mice and pharmacologic inhibition of PAI-1 activity by low-dose unfractionated heparin and enoxaparin.
We conclude that high-tidal-volume mechanical ventilation increased microvascular permeability, neutrophil influx, lung PAI-1 mRNA expression, production of active PAI-1. The deleterious effects were attenuated by low-dose unfractionated heparin or enoxaparin treatment. Understanding the protective mechanism of unfractionated heparin and enoxaparin related to the reduction of PAI-1 may afford further knowledge of the effects of mechanical forces in the lung and development of possible therapeutic strategies involved in acute lung injury.
Low-molecular-weight heparins (LMWH) appear to prolong survival of patients with cancer. Such a beneficial effect is thought to be associated with interruption of molecular mechanisms involving the heparan sulfate (HS) chains of cell surface and extracellular matrix proteoglycans (HSPGs), growth factors and their receptors, heparanase, and selectins. The beneficial effects of heparin species could also be associated with their ability to release tissue factor pathway inhibitor from endothelium. The utility of heparin and LMWH as anticancer drugs is limited due to their anticoagulant properties. Non-anticoagulant heparins can be obtained either by removing chains containing the antithrombin-binding sequence, or by inactivating critical functional groups or units of this sequence. The non-anticoagulant heparins most extensively studied are regioselectively desulfated heparins and 'glycol-split' heparins. Some modified heparins of both types are potent inhibitors of heparanase. A number of them also attenuate metastasis in experimental models. With cancer cells overexpressing selectins, heparin-mediated inhibition of tumor cells-platelets aggregation and tumor cell interaction with the vascular endothelium appears to be the prevalent mechanism of attenuation of early stages of metastasis. The structural requirements for inhibition of growth factors, heparanase, and selectins by heparin derivatives are somewhat different for the different activities. An N-acetylated, glycol-split heparin provides an example of application of a non-anticoagulant heparin that inhibits cancer in animal models without unwanted side effects. Delivery of this compound to mice bearing established myeloma tumors dramatically blocked tumor growth and progression.
Intravital video microscopy was used to investigate leukocyte margination in 80 mesenteric venules (19 to 54 microns) of 50 anesthetized rabbits. After intravenous (IV) bolus injection, sulfated polysaccharides reduced in a reversible and dose-dependent way the number of leukocytes rolling slowly along the venular wall. The presence of sulfate groups is essential because other negatively charged or neutral polysaccharides had no effect. It was not caused by an increase in RBC velocity or chelation of divalent cations. Inhibition by sulfated dextrans (n = 7) was independent of molecular weight (mol wt 13,000 to 500,000) but was influenced by the average number of sulfate groups per monosaccharide. With substitution 0.13, the 90%-inhibition dose was 104 mg/kg, with 0.7 it was 56 mg/kg, and between substitution 1 and 2 it ranged from 20 to 23 mg/kg. At 100 mg/kg, plasma concentration was 0.6 to 0.7 mg/mL. Xylan sulfate (mol wt 6,000, substitution 1.8) gave 90% inhibition at 11 mg/kg, and heparin gave 90% inhibition at 97 mg/kg. Duration of inhibition (0.5 to 2 hours) depended on mol wt and appeared to be related to plasma clearance. Because protamine also inhibited rolling (12 mg/kg; less than 10 minutes), we propose that repetitive formation and breakup of ionic bonds between sulfate groups and positively charged amino acids is involved in leukocyte rolling. During inhibition of rolling, systemic lymphocyte/monocyte levels appeared to increase. Granulocyte counts did not change, indicating that rolling is not the main mechanism responsible for the marginal granulocyte pool.
Incubation of human platelets, human neutrophils, or highly metastatic mouse lymphoma cells with sulfate-labeled extracellular matrix (ECM) results in heparanase-mediated release of labeled heparan sulfate cleavage fragments (0.5 less than Kav less than 0.85 on Sepharose 6B). This degradation was inhibited by native heparin both when brought about by intact cells or their released heparanase activity. Degradation of heparan sulfate in ECM may facilitate invasion of normal and malignant cells through basement membranes. The present study tested the heparanase inhibitory effect of nonanticoagulant species of heparin that might be of potential use in preventing heparanase mediated extravasation of bloodborne cells. For this purpose, we prepared various species of low-sulfated or low-mol-wt heparins, all of which exhibited less than 7% of the anticoagulant activity of native heparin. N-sulfate groups of heparin are necessary for its heparanase inhibitory activity but can be substituted by an acetyl group provided that the O-sulfate groups are retained. O-sulfate groups could be removed provided that the N positions were resulfated. Total desulfation of heparin abolished its heparanase inhibitory activity. Heparan sulfate was a 25-fold less potent heparanase inhibitor than native heparin. Efficiency of low-mol-wt heparins to inhibit degradation of heparan sulfate in ECM decreased with their main molecular size, and a synthetic pentasaccharide, representing the binding site to antithrombin III, was devoid of inhibitory activity. Similar results were obtained with heparanase activities released from platelets, neutrophils, and lymphoma cells. We propose that heparanase inhibiting nonanticoagulant heparins may interfere with dissemination of bloodborne tumor cells and development of experimental autoimmune diseases.
Initial attachment of leukocytes to the vessel wall at sites of inflammation is supported by a family of carbohydrate-binding adhesion molecules called the selectins. Selectin ligands include sialyl-Lewis x (sLex, Neu5Ac alpha 2–3Gal beta 1–4[Fuc alpha 1–3]GlcNAc--) and related structures. We report here that defined heparin oligosaccharides interact with the selectins. Heparin chains containing four or more monosaccharide residues inhibited the function of L- and P-selectin, but not E-selectin, in vitro. In a competition enzyme-linked immunosorbent assay measuring inhibition of solution-phase selectin-Ig fusion proteins (selectin-Ig) binding to immobilized bovine serum albumin-sLex neoglycoprotein, a heparin-derived tetrasaccharide mixture inhibited 50% of L- and P-selectin-Ig binding (IC50) at 200 +/- 40 mumol/L and 850 +/- 110 mumol/L, respectively. A single hexasulfated tetrasaccharide (delta UA2S alpha 1–4GlcNS6S alpha 1–4IdoA2S alpha 1- 4GlcNS6S) was particularly active against L- and P-selectin-Ig (IC50 = 46 +/- 5 mumol/L and 341 +/- 24 mumol/L). By comparison, the tetrasaccharide sLex was not inhibitory at concentrations up to 1 mmol/L. In cell adhesion assays, heparin tetrasaccharides reduced binding of neutrophils to COS cells expressing P-selectin but not to COS cells expressing E-selectin. They also blocked colon cancer cell adhesion to L- and P-selectin but not E-selectin. In a model of acute inflammation, intravenously administered heparin tetrasaccharides diminished influx of neutrophils into the peritoneal cavities of thioglycollate-treated mice. We conclude that heparin oligosaccharides, including non-anticoagulant tetrasaccharides, are effective L- and P- selectin inhibitors in vitro and have anti-inflammatory activity in vivo.
Fibrin deposits surrounding circulating tumor cells may protect them from mechanical trauma and destruction by the host immune system, and may facilitate microvascular entrapment required for metastasis. We report that heparin inhibited the clotting of plasma induced by mouse mammary carcinoma cells in a dose-dependent manner and blocked the production of experimental lung metastasis when administered i.p. at the time of intravenous injection of tumor cells. On the hand, O/N-desulfated N-acetylated heparin did not exhibit anticoagulant properties and had no effects on metastasis formation. Similarly, reduction of metastasis was not seen with N-desulfated N-acetylated heparin, another chemically modified heparin which does not inhibit blood coagulation but has heparanase inhibitory activity. Our data demonstrate the existence of a strong association between antimetastatic and anticoagulant properties of heparin species in the present experimental system.
Previous studies have demonstrated that the leukocyte integrin Mac-1 adheres to several cell surface and soluble ligands including intercellular adhesion molecule-1, fibrinogen, iC3b, and factor X. However, experiments with Mac-1-expressing transfectants, purified Mac-1, and mAbs to Mac-1 indicate the existence of additional ligands. In this paper, we demonstrate a direct interaction between Mac-1 and heparan sulfate glycans. Heparin affinity resins immunoprecipitate Mac-1, and neutrophils and transfectant cells that express Mac-1 bind to heparin and heparan sulfate, but not to other sulfated glycosaminoglycans. Inhibition studies with mAbs and chemically modified forms of heparin suggest the I domain as a recognition site on Mac-1 for heparin, and suggest that either N- or O-sulfation is sufficient for heparin to bind efficiently to Mac-1. Under conditions of continuous flow in which heparins and E-selectin are cosubstrates, neutrophils tether to E-selectin and form firm adhesions through a Mac-1-heparin interaction.
The successful penetration of endothelial basement membranes is an important process in the formation of hematogenous tumor metastases. Heparan sulfate (HS) proteoglycan is a major constituent of endothelial basement membranes, and we have found that HS-degradative activities of metastatic B16 melanoma sublines correlate with their lung-colonizing potentials. The melanoma HS-degrading enzyme is a unique endo-β-D-glucuronidase (heparanase) that cleaves HS at specific intrachain sites and is detectable in a variety of cultured human malignant melanomas. The treatment of B16 melanoma cells with heparanase inhibitors that have few other biological activities, such as N-acetylated N-desulfated heparin, results in significant reductions in the numbers of experimental lung metastases in syngeneic mice, indicating that heparanase plays an important role in melanoma metastasis. HS-degrading endoglycosidases are not tumor-specific and have been found in several normal tissues and cells. There are at least three types of endo-β-D-glucuronidases based on their substrate specificities. Melanoma heparanase, an Mr ∼96,000 enzyme with specificity for β-D-glucuronosyl-N-acetylglucosaminyl linkages in HS, is different from platelet and mastocytoma endoglucuronidases. Elevated levels of heparanase have been detected in sera from metastatic tumor-bearing animals and malignant melanoma patients, and a correlation exists between serum heparanase activity and extent of metastases. The results suggest that heparanase is potentially a useful marker for tumor metastasis.
The effects of an unfractionated heparin preparation (Multiparin), a low molecular weight heparin preparation (Fragmin) and a selectively O-desulphated derivative of heparin lacking anticoagulant activity, have been investigated for their effects on the adhesion of human polymorphonuclear leucocytes (PMNs) to cultured human umbilical vein endothelial cells (HUVECs) in vitro. The effect of poly-L-glutamic acid, a large, polyanionic molecule was also studied.
Unfractionated heparin (50–1000 U ml−1), the O-desulphated derivative (0.3–6 mg ml−1) and the low molecular weight heparin (50 U–1000 U ml−1) all inhibited significantly the adhesion of 51Cr labelled PMNs to HUVECs stimulated with interleukin-1β (IL-1β; 10 U ml−1), bacterial lipopolysaccharide (LPS; 2.5 μg ml−1) or tumour necrosis factor-α (TNF-α; 125 U ml−1) for 6 h, whereas poly-L-glutamic acid had no effect. In addition, the three heparin preparations in the same concentration range inhibited significantly the adhesion of f-met-leu-phe-stimulated PMNs to resting HUVECs.
The effects of unfractionated heparin upon the expression of adhesion molecules intercellular adhesion molecule-1 (ICAM-1) and E-selection were also investigated, as were the effects of unfractionated heparin upon adhesion of human PMNs to previously stimulated HUVECs. Heparin had little effect upon levels of expression of these adhesion molecules on stimulated HUVECs. However, a profound effect upon PMN adhesion to previously stimulated HUVECs was demonstrated using the same preparation, suggesting that inhibition of adhesion molecule expression is not a major component of the described inhibitory effects of heparin.
Pre-incubation of PMNs with heparin followed by washing inhibited their adhesion to HUVECs, under different conditions of cellular activation, implying that heparin can bind to these cells and exert its anti-adhesive effects even when not directly present in the system.
These observations would suggest that both heparin and a low molecular weight heparin are capable of inhibiting adhesion of human PMNs to endothelial cells, an effect not dependent solely upon the polyanionic nature of these molecules, nor dependent upon their ability to act as anticoagulants.
British Journal of Pharmacology (2000) 129, 533–540; doi:10.1038/sj.bjp.0703099
Heparan sulphate (HS), discovered in 1948 in heparin by-products, only emerged slowly from the shadow of heparin. Its inauspicious beginning was followed by the gradual realisation that HS was a separate entity with distinctive features. Both HS and heparin follow a common biosynthetic route but while heparin reaches full maturity, HS holds on to some of its youthful traits. The novel design and complex patterning of sulphation in HS enable it fulfil key roles in many, diverse biological processes.
Heparin and glycosaminoglycans (GAGs) related structurally to heparin, notably heparan sulphate, bind to most, if not all, chemokines and many growth factors. The chemokine and growth factor interactions with GAGs localise the peptide mediators to specific sites in tissues and influence their stability and function. This chapter discusses the nature of these interactions and the effect on the function of a number of chemokines (PF-4, interleukin-8, RANTES and SDF-1) and growth factors (FGF, HGF, VEGF) in normal physiology and the disease setting. Novel therapeutic interventions that target chemokine and growth factor interactions with GAGs are also discussed.
Thermochromism and optical absorption in mono‐ and multilayers of Langmuir–Blodgett films of poly(3‐alkylthiophenes), poly(3‐octyl‐2,2’‐bithiophene), and poly(3’‐octyl‐2,2’;5’,2‘‐terthiophene) were studied. In sparsely alkylated polythiophenes the magnitude of the thermochromic shift was smaller than in poly(3‐alkylthiophenes) and roughly proportional to the sidechain concentration. Results of Valence Effective Hamiltonian calculations were compared with the experimental results of thermochromism. A vibronic structure was found in the absorption spectra of Langmuir–Blodgett films at room temperature. The vibronic splitting in poly(3‐hexylthiophene) was approximately 0.18 eV as previously has been observed in poly(3‐alkylthiophenes) but in poly(3’‐octyl‐2,2’;5’,2‘‐terthiophene) it was 0.20–0.25 eV. The vibronic peaks stay approximately at constant energies and vanish at elevated temperatures.
A significant proportion of cytokines bind to glycosaminoglycans such as heparin. Glycosaminoglycans are involved in signaling, stabilization and/or storage of these cytokines. Typical examples of glycosaminoglycan-binding cytokines are basic fibroblast growth factor (bFGF), interleukin-8 (IL-8), monocyte chemoattractant protein-1 (MCP-1), vascular endothelial growth factor (VEGF), VEGF-C, hepatocyte growth factor (HGF), granulocyte colony-stimulating factor (G-CSF), midkine, and pleiotrophin. All are present in the tumor microenvironment and promote tumor growth, tumor invasion and/or tumor angiogenesis. Serum or plasma levels of glycosaminoglycan-binding cytokines are frequently elevated in patients with various malignant tumors. High levels of these cytokines are usually correlated with the occurrence of metastasis and a poor prognosis. The mode of elevation of individual glycosaminoglycan-binding cytokines in patients with malignant tumors is summarized here. Further studies, especially with multiple cytokines, are expected to make assays clinically useful for both early detection and prognostic prediction.
Clinical and experimental studies have suggested that unfractionated heparin (UFH) effects malignancy progression. We reviewed all published clinical reports concerning the effects of UFH, as compared to no treatment on survival of cancer patients. Studies were classified on methodological strength and subdivided as to whether therapeutic or prophylactic dosages of UFH were used. Mortality rates after 3 years were extracted or calculated. One randomized study that evaluated the use of UFH in therapeutic dosages in patients with small cell lung carcinoma reported on an improved survival (odds ratio (OR) 0.64; 95% confidence interval (CI): 0.25 to 1.62). A detrimental effect was observed in 2 randomized studies which investigated the effects of intraportal UFH treatment in a prophylactic dose after surgery for gastrointestinal cancer (OR 1.66; 95% CI: 1.02 to 2.71). In contrast, level 2 studies in which either therapeutic or prophylactic dosages of UFH on mortality of patients with gastrointestinal cancer were evaluated, showed OR of 0.58 (95% CI; 0.11-3.13) and 0.65 (95% CI 0.51 to 0.84), respectively. We conclude that there is no convincing evidence of either positively or negatively effects of UFH on survival of patients with malignancy.
Harry R. Büller is an Established Investigator of the Dutch Heart Foundation
We have accumulated multiple lines of evidence supporting the ability of HB-EGF to protect the intestines from injury and to augment the healing of partial-thickness scald burns of the skin. The aim of the current study was to investigate the role of heparin-binding EGF-like growth factor (HB-EGF) in intestinal anastomotic wound healing.
HB-EGF (-/-) knockout (KO) mice (n=42) and their HB-EGF (+/+) wild type (WT) counterparts (n=33), as well as HB-EGF transgenic (TG) mice (n=26) and their (WT) counterparts (n=27), underwent division and reanastomosis of the terminal ileum. In addition, WT mice (n=21) that received enteral HB-EGF (800 μg/kg) underwent the same operative procedure. Anastomotic bursting pressure was measured at 3 and 6 d postoperatively. Tissue sections were stained with hematoxylin and eosin to assess anastomotic healing, and Picrosirus red to assess collagen deposition. Immunohistochemistry using anti-von Willebrand factor antibodies was performed to assess angiogenesis. Complications and mortality were also recorded.
HB-EGF KO mice had significantly lower bursting pressures, lower healing scores, higher mortality, and higher complication rates postoperatively compared with WT mice. Collagen deposition and angiogenesis were significantly decreased in KO mice compared with WT mice. Conversely, HB-EGF TG mice had increased anastomotic bursting pressure, higher healing scores, lower mortality, lower complication rates, increased collagen deposition, and increased angiogenesis postoperatively compared with WT mice. WT mice that received HB-EGF had increased bursting pressures compared with non-HB-EGF treated mice.
Our results demonstrate that HB-EGF is an important factor involved in the healing of intestinal anastomoses.
This study tests the feasibility of inhalable pegylated liposomal formulations of low molecular weight heparin (LMWH) for treatment of two clinical manifestations of vascular thromboembolism: deep vein thrombosis (DVT) and pulmonary embolism (PE). Conventional distearoyl-sn-glycero-3-phosphoethanolamine (DSPE) and long-circulating pegylated (DSPE-PEG-2000 and DSPE-PEG-5000) liposomes were prepared by hydration method. Formulations were evaluated for particle size, entrapment efficiency, stability, pulmonary absorption, anticoagulant, and thrombolytic effects in rats. Pulmonary absorption was monitored by measuring plasma antifactor Xa activity; anticoagulant and thrombolytic effects were studied by measuring reduction in thrombus weight and amount of dissolved radioactive clot in the blood, respectively. Pegylated liposomal were smaller and showed greater drug entrapment efficiency than conventional liposomes. All formulations produced an increase in pulmonary absorption and circulation time of LMWH upon first dosing. Three repeated dosings of conventional liposomes resulted in decreased half-life and bioavailability; no changes in these parameters were observed with pegylated liposomes. PEG-2000 liposomes were effective in reducing thrombus weight when administered every 48 h over 8 days. In terms of thrombolytic effects and dosing frequency, PEG-2000 liposomes administered via the pulmonary route at a dose of 100 U/kg were as effective as 50 U/kg LMWH administered subcutaneously. This paper suggests that inhalable pegylated liposomes of LMWH could be a potential noninvasive approach for DVT and PE treatment.
Heparin and its improved version, low-molecular weight heparin (LMWH), are known to exert polypharmacological effects at various levels. Early studies focused on the plasma anti-Xa and anti-IIa pharmacodynamics of different LMWHs. Other important pharmacodynamic parameters for heparin and LMWH, including effects on vascular tissue factor pathway inhibitor (TFPI) release, inhibition of inflammation through NFkappaB, inhibition of key matrix-degrading enzymes, selectin modulation, inhibition of platelet-cancer cell interactions, and inflammatory cell adhesion, help explain the diverse clinical impact of this class of agents in thrombosis and beyond.
Heparin is commonly used for prevention or treatment of cancer-associated thromboembolism. Recent clinical evidence indicates that heparin, and low-molecular weight heparin improves survival of cancer patients. Experimental evidence from various animal models consistently supports the ability of heparin to attenuate metastasis. Heparin, apart from its anticoagulant activity contains a variety of biological activities possibly affecting cancer progression, including: inhibition of heparanase, blocking of P- and L-selectin mediated cell adhesion, and inhibition of angiogenesis. The delineation of antimetastatic activity of heparin is in the focus of several ongoing investigations. This review summarizes the current experimental evidence on the biology of heparin as a potential treatment cancer progression.
High-molecular-weight sodium heparin (10,000 IU) has been developed based on studies conducted on burn patients; it has anti-inflammatory, antigenic and anticoagulant properties.
The aim of this paper was to evaluate the effects of topical application of sodium heparin spray on two immunosuppressed patients (a child and a young person) with perineal dermatitis and an immunosuppressed child with second-degree burns.
This is a report of three clinical cases treated in a pediatric hospital. Sodium heparin spray (10,000 IU) was applied at a dose of 4200 IU per percentage of body surface area affected over the hyperemic region. Heparin spray treatment was discontinued after crust formation and wound reepithelialization; essential fatty acid was applied until spontaneous separation of the crust or total wound reepithelialization.
Heparin spray had analgesic, angiogenic and anti-inflammatory effects, and did not require secondary wound closure. Pain control was of fundamental importance to the patients; in the three cases, improvement in analgesia was achieved within 24 h of treatment.
The topical application of heparin spray in patients with perineal dermatitis or superficial second-degree burns demonstrated good tolerability, resulted in good aesthetic outcomes, and reduced pain.
Heparin is known to possess anti-inflammatory properties that in many cases appear to be separable from its anticoagulant activity. Mast cells, located in tissue, are the sole source of endogenous heparin, which may be involved in control of the inflammatory response. The majority of studies of the effects of heparin on the inflammatory response, carried out to date, have involved systemic administration and the potential influence of heparin in the site of inflammation has been less clear. In the present study, the effects of locally administered heparin and a non-anticoagulant derivative were investigated on leucocyte accumulation in the inflamed peritoneal cavity and leucocyte-endothelial interactions in the mesenteric microcirculation of the rat. Heparin and non-anticoagulant heparin inhibited the influx of neutrophils to the site of inflammation, as well as leucocyte rolling and adhesion in post-capillary venules. These effects were apparent only while heparin was present in the peritoneal cavity and plasma and may reflect, in part, an action on resident peritoneal cells, as the heparins tested were found also to inhibit the expression of endothelial adhesion molecules in response to products of activated mononuclear cells, in vitro. Our data show that locally administered heparin has anti-inflammatory effects in an in vivo model of peritoneal inflammation whilst present at the site of inflammation. These non-anticoagulant properties may involve interaction with cells in the site of inflammation, in addition to inhibiting cell adhesion at the level of the microcirculation.
The elucidation of the structure of the antithrombin binding sequence in heparin has given a large impulse to the rational design of heparin related drugs. De novo chemical synthesis of the corresponding pentasaccharide as well as simplified analogues has provided very specific, antithrombin-mediated inhibitors of factor Xa with various pharmacokinetic profiles. Fondaparinux and idraparinux are examples of such compounds that have found clinical application as antithrombotics. Because of the very specific binding to antithrombin the pharmacokinetics of pentasaccharides can be predicted and transferred to other molecules covalently bound to them. The new chemical entities thus obtained display a wide array of antithrombotic activities, giving improved heparin molecules as well as new anticoagulants, devoid of the undesired side effects of heparin and with unprecedented pharmacological profiles. In this context, a direct thrombin inhibitor was covalently coupled to a pentasaccharide by an inert spacer. This compound, EP42675 exerts antithrombin mediated anti-factor Xa activity together with direct thrombin inhibiting capacity. It displays favourable pharmacokinetics as imposed by the pentasaccharide. EP42675 was further modified by the introduction of a biotin moiety in its structure. The new entity obtained, EP217609 exerts the same pharmacological profile as EP42675 and it can be instantaneously neutralised by injection of avidin. Due to this unprecedented mechanism of anticoagulant activity and its ability to be neutralised, EP217609 deserves to be investigated in clinical settings where direct thrombin inhibition is required.
