Thomas Pufe
Research interests
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InterestsGrowth Factors, Angiogenesis, Osteoarthritis, Rheumatoid Arthritis, Tendons, Bone Biology
Publications
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0.88Impact points
Mechanisms of proximal hamstring rupture in a non-athlete healthy middle-aged female.
Annals of anatomy = Anatomischer Anzeiger : official organ of the Anatomische Gesellschaft. 04/2012;
PURPOSE: To present an explicatory pathophysiological model for the rare clinical case of a total proximal hamstring rupture for the first time in the literature. METHODS: A non-athletic healthy female (49 years) experienced a complete rupture of the right conjoint tendon of the biceps femoris (long... [more] PURPOSE: To present an explicatory pathophysiological model for the rare clinical case of a total proximal hamstring rupture for the first time in the literature. METHODS: A non-athletic healthy female (49 years) experienced a complete rupture of the right conjoint tendon of the biceps femoris (long head) and semitendinosus muscle while slipping down a lawn-covered slope (eccentric hip flexion and knee extension during stance phase of gait after heel-strike). A hamstring rupture was diagnosed by clinical examination and confirmed by magnet resonance imaging (MRI). Surgical reattachment of the conjoint tendon to the ischial tuberosity was performed. One year after surgery, she experienced no pain or functional impairment. RESULTS: Histological analysis and immune-histochemical staining (vascular endothelial growth factor - receptor 2) of a biopsy taken intra-operatively revealed signs of fibroblast proliferation and vasculoneogenesis with absence of inflammatory changes indicating that repairing mechanisms and tissue remodeling had been taking place. CONCLUSION: This case report provides evidence for the hypothesis that micro-injuries induce repairing mechanisms and thus tissue remodeling which leads to consecutive tissue weakening and mechanical failure during a non-adequate trauma. Micro-injuries can occur during leisure activities and remain clinically invisible until rupture.
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0.88Impact points
Detection of vascular endothelial growth factor (VEGF) in moderate osteoarthritis in a rabbit model.
Annals of anatomy = Anatomischer Anzeiger : official organ of the Anatomische Gesellschaft. 02/2012;
INTRODUCTION: Vascular endothelial growth factor (VEGF) is detectable in later stages of human osteoarthritis (OA), but not in the healthy articular cartilage. Due to its capacity to increase matrix metalloproteinases and to decrease their inhibitors (tissue inhibitors of metalloproteinases or TIMPs... [more] INTRODUCTION: Vascular endothelial growth factor (VEGF) is detectable in later stages of human osteoarthritis (OA), but not in the healthy articular cartilage. Due to its capacity to increase matrix metalloproteinases and to decrease their inhibitors (tissue inhibitors of metalloproteinases or TIMPs) VEGF seems to play an important role in the development of osteoarthrosis. In late stages of osteoarthritis, invasion of blood vessels from the subchondral growth plate, synovitis with angiogenesis and osteophyte growth is observable. Several studies have revealed a central role for VEGF in all these phenomena. In order to investigate whether VEGF participates in early changes of OA or may even possess characteristics of a marker of OA, we developed an experimental posttraumatic OA New Zealand White rabbit animal model. MATERIALS AND METHODS: In four skeletally mature New Zealand White rabbits, OA was induced by joint instability after transsection of the anterior cruciate ligament in both knees. After eight weeks the animals were killed. OA was verified histologically using the Mankin scale. Expression of VEGF was detected by immunohistochemistry and RT-PCR. Proteoglycans were evaluated by using HE and safranin-O staining. Four non-surgically treated animals acted as a control. RESULTS: The mean Mankin score was 5.11 (±2.14), corresponding to a moderate OA. VEGF and VEGF transcripts were detectable in the cartilage of early experimental posttraumatic OA rabbits. Control samples remained negative for VEGF mRNA and protein. DISCUSSION: The results of this study are promising concerning the role of VEGF as a diagnostic marker. VEGF could further be participated in early changes of OA. A therapeutic approach by modulation of VEGF production could be a possibility for the future.
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5.33Impact points
Interplay between vascular endothelial growth factor (VEGF) and nuclear factor erythroid 2-related factor-2 (Nrf2): implications for preeclampsia.
The Journal of biological chemistry. 12/2011; 286(50):42863-72.
Several recently published studies have suggested that decreasing VEGF levels result in placental oxidative stress in preeclampsia, although the question as to how decreased VEGF concentrations increase oxidative stress still remains unanswered. Here, we show that VEGF activated Nrf2, the main regul... [more] Several recently published studies have suggested that decreasing VEGF levels result in placental oxidative stress in preeclampsia, although the question as to how decreased VEGF concentrations increase oxidative stress still remains unanswered. Here, we show that VEGF activated Nrf2, the main regulating factor of the intracellular redox balance, in the cytotrophic cell line BeWo. In turn, this activated the production of antioxidative enzymes thioredoxin, thioredoxin reductase, and heme oxygenase-1, which showed a decrease in their expression in the placentas of preeclamptic women. Nevertheless, this activation occurred without oxidative stress stimulus. As a consequence, the activation of Nrf2 protected BeWo cells against H(2)O(2)/Fe(2+)-induced oxidative damage. We further show that VEGF up-regulated the expression of itself. A positive feedback loop was described in which VEGF activated Nrf2 in an ERK1/2-dependent manner; the up-regulation of HO-1 expression by Nrf2 augmented the production of carbon monoxide, which in turn up-regulated VEGF expression. In conclusion, VEGF induces the Nrf2 pathway to protect against oxidative stress and, via a positive feedback loop, to elevate VEGF expression. Therefore, decreased VEGF bioavailability during preeclampsia may result in higher vulnerability to placental oxidative cell damage and a further reduction of VEGF bioavailability, a vicious circle that may end up in preeclampsia.
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1.91Impact points
Effects of controlled released BMP-7 on markers of inflammation and degradation during the cultivation of human osteoarthritic chondrocytes.
Journal of biomaterials applications. 11/2011; 26(4):419-33.
The aim of the present study is to investigate the effects of BMP-7 released from polylactide microspheres on the appearance of various catabolic and inflammatory cytokines secreted by osteoarthritic chondrocytes cultivated in a collagen gel. Articular chondrocytes of 15 patients suffering from oste... [more] The aim of the present study is to investigate the effects of BMP-7 released from polylactide microspheres on the appearance of various catabolic and inflammatory cytokines secreted by osteoarthritic chondrocytes cultivated in a collagen gel. Articular chondrocytes of 15 patients suffering from osteoarthritis are transferred to a collagen type-I gel. Additionally, BMP-7 encapsulated into polylactide microspheres (50 ng BMP-7/mL gel) is added. After 14 days, gene expression and protein appearance of various genes involved in matrix turnover and inflammation are investigated by immunohistochemical staining and RT-PCR and compared to untreated controls. TNF-α, MMP-13, IL-6, IL-1β, and VEGF gene expressions are decreased in the treatment group. In contrast, BMP-7-induced matrix synthesis is not affected, leaving collagen type-II (Col-II) gene expression to be elevated, while collagen type-I (Col-I) is decreased. In summary, controlled release of low concentrated BMP-7 from polylactide microspheres leads to a decrease in gene expression of the investigated inflammation and matrix degradation markers whereas matrix synthesis is induced.
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1.18Impact points
Impact of Nrf2 on esophagus epithelium cornification.
International journal of dermatology. 11/2011; 50(11):1362-5.
Nrf2 is a transcription factor that is known to maintain cellular defense against the toxicity of electrophiles and reactive oxygen species (ROS). We show an effect of Nrf2 deficiency on the histology of the esophagus of Nrf2 knockout mice. Quantitative analysis of esophageal cornification via hemat... [more] Nrf2 is a transcription factor that is known to maintain cellular defense against the toxicity of electrophiles and reactive oxygen species (ROS). We show an effect of Nrf2 deficiency on the histology of the esophagus of Nrf2 knockout mice. Quantitative analysis of esophageal cornification via hematoxylin and eosin (H&E) staining revealed significantly (P=0.0127) decreased stratification in Nrf2 knockout mice compared with wild-type controls. In addition, we show that Nrf2 is expressed solely in the stratum spinosum and not in the stratum basale of the epidermis. This expression pattern is exactly the same as those described for keratin K6 and K16. We conclude that Nrf2 regulates the cornification of epithelia and may play a role in callus formation and wound healing of the skin, as well as in skin aging.
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2.27Impact points
Platelets display potent antimicrobial activity and release human beta-defensin 2.
Platelets. 09/2011;
Platelet-rich plasma (PRP) is a potent agent that improves soft tissue and bone healing. By the release of growth factors and cytokines, PRP is believed to locally boost physiologic healing processes. Recently, antimicrobial activity of PRP has been demonstrated against S. aureus strains. Major scie... [more] Platelet-rich plasma (PRP) is a potent agent that improves soft tissue and bone healing. By the release of growth factors and cytokines, PRP is believed to locally boost physiologic healing processes. Recently, antimicrobial activity of PRP has been demonstrated against S. aureus strains. Major scientific effort is being put into the understanding and prevention of infections i.e. by delivery of antimicrobial substances. In previous studies we showed the ideal antibacterial activity-profile of the human beta-defensin 2 (hBD-2) for orthopaedic infections and therefore hypothesized that hBD-2 may be the effector of antimicrobial platelet action. Platelet concentrates were produced from human platelet phresis obtained from a hospital blood bank. They were screened by immunohistochemistry, Western Blot and ELISA for the human beta defensin-2. In vitro susceptibility to PRP was investigated by a standard disc diffusion test with or without pre-incubation of PRP with anti-hBD-2 antibody. SPSS statistical software was used for statistical analysis. PRP contains hBD-2 470 pg/10(9) platelets or 1786 pg/ml, respectively, (ELISA), which was confirmed by immunohistochemistry and Western Blot. In antimicrobial testing, PRP demonstrates effective inhibition of E. coli, B. megaterium, P. aeruginosa, E. faecalis and P. mirabilis. With this study we confirm the previously reported antimicrobial action of platelet concentrates i.e. PRP. In opposition to previously reported effects against gram positive bacteria our study focuses on gram negative and less common gram positive bacteria that do frequently cause clinical complications. We provide a possible molecular mechanism at least for E. coli and P. mirabilis for this effect by the detection of an antimicrobial peptide (hBD-2). This study may advocate the clinical use of PRP by highlighting a new aspect of platelet action.
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2.72Impact points
Nrf2 expression by neurons, astroglia, and microglia in the cerebral cortical penumbra of ischemic rats.
Journal of molecular neuroscience : MN. 09/2011; 46(3):578-84.
Experimental animal studies have demonstrated that oxidative stress plays an essential role during ischemic stroke. In addition to oxidizing macromolecules leading to cell injury, oxidants are also involved in cell death/survival signal pathways and cause mitochondrial dysfunction. Nuclear factor er... [more] Experimental animal studies have demonstrated that oxidative stress plays an essential role during ischemic stroke. In addition to oxidizing macromolecules leading to cell injury, oxidants are also involved in cell death/survival signal pathways and cause mitochondrial dysfunction. Nuclear factor erythroid 2-related factor 2 (Nrf2) represents one of the major regulators implicated in the endogenous defense system against oxidative stress. We have studied the expression and activation status of Nrf2 under stroke-like conditions using the temporary middle cerebral artery occlusion rat model. Inactive Nrf2 is proteasomal degraded within minutes but stabilized during activation. We analyzed Nrf2 activation and the resulting accumulation in post-ischemic rat brain cells using double immunofluorescence staining with antibodies directed against Nrf2 and cell type-specific markers. The core infarct region showed no obvious positive staining signal for Nrf2 24 h after the initiation of artery occlusion. However, Nrf2 immunoreactivity was detectable in the ipsilateral penumbra where microglia, astrocytes, and neurons contained Nrf2. Interestingly, Nrf2 was also significantly upregulated in neurons but not in other cell types of the unaffected contralateral site. These results provide strong evidence that Nrf2 is involved in acute stroke-dependent neurodegeneration in the penumbra but not core region and indicate the presence of a systemic Nrf2 activator independent from oxidative stress.
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4.15Impact points
Intraarticular injection of platelet-rich plasma reduces inflammation in a pig model of rheumatoid arthritis of the knee joint.
Arthritis and rheumatism. 07/2011; 63(11):3344-53.
Treatment options for rheumatoid arthritis range from symptomatic approaches to modern molecular interventions such as inhibition of inflammatory mediators. Inhibition of inflammation by platelet-rich plasma (PRP) has been proposed as a treatment for tendinitis and osteoarthritis. The present study ... [more] Treatment options for rheumatoid arthritis range from symptomatic approaches to modern molecular interventions such as inhibition of inflammatory mediators. Inhibition of inflammation by platelet-rich plasma (PRP) has been proposed as a treatment for tendinitis and osteoarthritis. The present study was undertaken to investigate the effect of PRP on antigen-induced arthritis (AIA) of the knee joint in a large animal model. Six-month-old pigs (n = 10) were systemically immunized by bovine serum albumin (BSA) injection, and arthritis was induced by intraarticular BSA injection. PRP was injected into the knee joints of 5 of the animals after 2 weeks. An additional 5 animals received no systemic immunization (controls). Signs of arthritis were documented by plain histologic analysis, Safranin O staining, and immunohistochemistry analysis for type II collagen (CII), interleukin-6 (IL-6), and vascular endothelial growth factor (VEGF). Interleukin-1β (IL-1β), IL-6, tumor necrosis factor α (TNFα), VEGF, and insulin-like growth factor 1 (IGF-1) protein content was measured by Luminex assay. In the pigs with AIA, plain histologic analysis revealed severe arthritic changes in the synovium. Safranin O and CII staining showed decreased proteoglycan and CII content in cartilage. Immunohistochemistry analysis revealed increased levels of IL-6 and VEGF in synovium and cartilage, and protein concentrations of IL-6, VEGF, IL-1β, and IGF-1 in synovium and cartilage were elevated as well; in addition, TNFα protein was increased in cartilage. Treatment with PRP led to attenuation of these arthritic changes in the synovium and cartilage. We have described a porcine model of AIA. Experiments using this model demonstrated that PRP can attenuate arthritic changes as assessed histologically and based on protein synthesis of typical inflammatory mediators in the synovial membrane and cartilage.
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2.38Impact points
Scaffolds for bone healing: concepts, materials and evidence.
Injury. 06/2011; 42(6):569-73.
Critical sized bone defects have to be filled with material to allow bone healing. The golden standard for this treatment is autogenous bone grafting. Because of donor size morbidity, equivalent synthetic bone scaffolds should be developed. Different materials, especially ceramics and polymers are i... [more] Critical sized bone defects have to be filled with material to allow bone healing. The golden standard for this treatment is autogenous bone grafting. Because of donor size morbidity, equivalent synthetic bone scaffolds should be developed. Different materials, especially ceramics and polymers are in the focus of research. Calcium phosphate ceramics show similar properties to bone and are degradable. Different modifications can improve the bioactive features. This article gives an overview about the current materials and their evidence of clinical use.
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2.38Impact points
Multiple trauma induces serum production of host defence peptides.
Injury. 05/2011; 43(2):137-42.
Today multiple trauma still is associated with a high mortality. Although severe open fractures and wounds can give rise to local infections and sepsis, the overall infection rate of multiply injured patients is surprisingly low. We have investigated serum of multiply injured patients with respect t... [more] Today multiple trauma still is associated with a high mortality. Although severe open fractures and wounds can give rise to local infections and sepsis, the overall infection rate of multiply injured patients is surprisingly low. We have investigated serum of multiply injured patients with respect to antibacterial properties and screened for host defence peptides (HDP) that constitute a class of fast acting and rapidly available molecules preventing bacterial infection. Serum specimens were obtained from multiply injured patients. Radial diffusion assays were performed to investigate antimicrobial properties. Ultrafiltration and heat-inactivation were used to rule out antimicrobial activity of large proteins i.e. complement factors. ELISA was performed to analyse serum concentrations of the human beta-defensins 2 and 3 (hBD-2 and hBD-3), LL-37 and the proinflammatory cytokines interferon-gamma (IFN-γ) and interleukin-6 (IL-6). Serum of multiply injured patients showed greater zones of inhibition in antimicrobial testing against Gram negative und positive bacteria. This effect was mediated by proteins smaller than 10 kDa, inactivation of the complement system does not significantly reduce antibacterial action. hBD-2, hBD-3 and LL-37 concentrations were significantly elevated after trauma and followed different characteristic concentration curves. Similar patterns of concentration profiles were recorded for hBD-2/IL-6 and hBD-3/IFN-γ suggesting a stimulatory influence within their induction process. With this study we provide evidence, that serum of multiply injured patients has by far higher antibacterial capacity than that of healthy donors. As possible mediators we have detected the HDP hBD-2, hBD-3 and LL-37 and their inducers in serum of multiply injured patients.
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3.02Impact points
Platelet-released growth factors can accelerate tenocyte proliferation and activate the anti-oxidant response element.
Histochemistry and cell biology. 05/2011; 135(5):453-60.
Little is know about the pathophysiology of acute and degenerative tendon injuries. Although most lesions are uncomplicated, treatment is long and unsatisfactory in a considerable number of cases. Besides the common growth factors that were shown to be relevant for tendon integrity more recently pro... [more] Little is know about the pathophysiology of acute and degenerative tendon injuries. Although most lesions are uncomplicated, treatment is long and unsatisfactory in a considerable number of cases. Besides the common growth factors that were shown to be relevant for tendon integrity more recently protection against oxidative stress was shown to promote tendon healing. To improve tendon regeneration, many have advocated the use of platelet-rich plasma (PRP), a thrombocyte concentrate that can serve as an autologous source of growth factors. In this study, we investigated the effect of platelet-released growth factors (PRGF) on tenocytes. Tenocytes were isolated from the Achilles tendon of postnatal rats. Tenocyte cell cultures were stimulated with PRGF. We used a CyQuant assay and WST assay to analyse tendon cell growth and viability in different concentrations of PRGF. Migration and proliferation of cells grown in PRGF were assessed by a scratch test. A dual-luciferase assay was used to demonstrate the activation of the anti-oxidant response element (ARE) in tenocytes. A positive effect of PRGF could be shown on tendon cell growth and migratory capacity. PRGF activated the Nrf2-ARE pathway in a dose-dependent manner. Here, we provide evidence of a biological effect of PRGF on tenocytes by the promotion of tenocyte growth and activation of the Nrf2-ARE pathway. This is a novel aspect of the action of platelet concentrates on tendon growth.
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3.11Impact points
Nitrate patch prevents steroid-related bone necrosis.
Journal of orthopaedic research : official publication of the Orthopaedic Research Society. 04/2011; 29(10):1517-20.
Avascular necrosis of the femoral head is a common complication with disabling effect for young patients after high-dose corticosteroid treatment. We could show that steroids have a vasoconstrictive effect on lateral epiphyseal arteries of the femoral head which could lead to ischemia and subsequent... [more] Avascular necrosis of the femoral head is a common complication with disabling effect for young patients after high-dose corticosteroid treatment. We could show that steroids have a vasoconstrictive effect on lateral epiphyseal arteries of the femoral head which could lead to ischemia and subsequent necrosis. In this study we investigated the preventive effect of a nitrate patch on steroid-related bone necrosis in a rabbit model. New Zealand White rabbits (male; 3-4.5 kg bodyweight) were injected with 20 mg/kg bodyweight methylprednisolone (GC group; n = 6). Control animals (n = 6) were treated with phosphate-buffered saline. A third group (GC + N; n = 6) additionally received a nitrate patch (0.675 mg/day). Four weeks after i.m. methylprednisolone injection the animals were sacrificed. For histology and immunohistochemistry, tissue samples were fixed in 3% paraformaldehyde, embedded in paraffin, sectioned, dewaxed, and stained with Ladewig. For quantification of empty lacunae, a histologic sign of FHN, histomorphometry was performed. Histomorphometry revealed a significant increase of empty lacunae in glucocorticoid-treated animals compared to controls and GC + N-treated animals. No significant difference in empty lacunae count was detected between the GC + N group and controls. HE staining revealed the different osteocyte amount in the GC versus GC and nitrate patch-treated groups. This study demonstrates an increased number of empty osteocyte lacunae representing a pathologic feature of osteonecrosis, in the GC group. Less empty lacunae were counted in the GC animals after additional treatment with a nitrate patch. This finding suggests that nitrate co-treatment has the potential to prevent steroid-associated FHN.
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0.31Impact points
[Avascular necrosis of the hip - diagnosis and treatment].
Zeitschrift für Orthopädie und Unfallchirurgie. 03/2011; 149(2):231-40; quiz 241-2.
Femoral head necrosis is an ischaemic bone necrosis of traumatic or nontraumatic pathogenesis which can lead to hip joint destruction in young age. It is today the indication for 10 % of all the total hip joint replacements. Known aetiologies of nontraumatic femoral head necrosis are alcoholism, ste... [more] Femoral head necrosis is an ischaemic bone necrosis of traumatic or nontraumatic pathogenesis which can lead to hip joint destruction in young age. It is today the indication for 10 % of all the total hip joint replacements. Known aetiologies of nontraumatic femoral head necrosis are alcoholism, steroids, sickle cell anaemia, caisson, and Gaucher's disease. Further risk factors are chemotherapy, chronic inflammatory bowel disease, systemic lupus erythematosus, and multiple sclerosis, in which also steroids are involved. Gravidity is another risk factor, but still idiopathic pathogenesis is found. In diagnosis, the ARCO-classification of the Association for the Research of Osseous Circulation is essential. While stage 0 can only be found histologically, the reversible early stage 1 shows MR signal changes. In the irreversible early stage 2, first native x-ray changes are seen as lower radiolucency reflects new bone apposition on dead trabeculae. In stage 3, subchondral fracture follows, and in stage 4 secondary arthritis of the hip. Established therapy in stage 1 is core decompression, physiotherapy, and more and more also bisphosphonates. Sufficient data to support extracorporeal shock wave therapy are still lacking. Stem cell therapy seems to be a promising new therapy method in stage 2. In stage 2 and 3 mainly proximal femoral osteotomies and (non)vascularised bone transplantation are performed. In stage 4, depending on size and location of the necrotic zone and pathology of the adjacent bone, resurfacing or short stem hip arthroplasty can be performed. However, conventional THA is still golden standard. The problem and challenge, however, is the often young patient age in femoral head necrosis. Especially chemotherapy-associated osteonecrosis in leukaemia is found in patients in their second decade of life. Therefore, the hip should be preserved as long as possible.
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5.33Impact points
Nrf2 induces interleukin-6 (IL-6) expression via an antioxidant response element within the IL-6 promoter.
The Journal of biological chemistry. 02/2011; 286(6):4493-9.
IL-6 gene expression is controlled by a promoter region containing multiple regulatory elements such as NF-κB, NF-IL6, CRE, GRE, and TRE. In this study, we demonstrated that TRE, found within the IL-6 promoter, is embedded in a functional antioxidant response element (ARE) matching an entire ARE con... [more] IL-6 gene expression is controlled by a promoter region containing multiple regulatory elements such as NF-κB, NF-IL6, CRE, GRE, and TRE. In this study, we demonstrated that TRE, found within the IL-6 promoter, is embedded in a functional antioxidant response element (ARE) matching an entire ARE consensus sequence. Further, point mutations of the ARE consensus sequence in the IL-6 promoter construct selectively eliminate ARE but not TRE activity. Nrf2 is a redox-sensitive transcription factor which provides cytoprotection against electrophilic and oxidative stress and is the most potent activator of ARE-dependent transcription. Using Nrf2 knock-out mice we demonstrate that Nrf2 is a potent activator of IL-6 gene transcription in vivo. Moreover, we show evidence that Nrf2 is the transcription factor that activates IL6 expression in a cholestatic hepatitis mouse model. Our findings suggest a possible role of IL-6 in oxidative stress defense and also give indication about an important function for Nrf2 in the regulation of hematopoietic and inflammatory processes.
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2.38Impact points
Thrombocytes are effectors of the innate immune system releasing human beta defensin-3.
Injury. 02/2011; 42(7):682-6.
Thrombocyte concentrate i.e. platelet-rich plasma (PRP) has become a popular adjunct for many surgical procedures. It is believed to improve bone and soft tissue healing. Recently antimicrobial effects of the autologous preparation were reported by several groups. In this study we investigated the a... [more] Thrombocyte concentrate i.e. platelet-rich plasma (PRP) has become a popular adjunct for many surgical procedures. It is believed to improve bone and soft tissue healing. Recently antimicrobial effects of the autologous preparation were reported by several groups. In this study we investigated the antimicrobial effect of PRP against gram-negative microbes which frequently cause severe complications in orthopaedic trauma surgery. Platelet-rich plasma was produced from liquid preserved thrombocyte concentrates. ELISA, Western blot and immunohistochemistry were preformed to investigate the release and content of platelet concentrates. A radial diffusion assay was used to detect antimicrobial effects of PRP. We detected the human beta defensin-3 in bactericidal concentrations in platelet preparations by ELISA, Western blot and immunohistochemistry. In antimicrobial testing we demonstrated effective inhibition of Escherichia coli (ATCC 11303), Bacterium megaterium (ATCC 14581), Klebsiella pneumoniae (ATCC 13883), Enterococcus faecalis (ATCC 29212) and Proteus mirabilis (ATCC21100). With this study we demonstrate antimicrobial action of a popular adjunct for orthopaedic and trauma surgery against gram-positive and gram-negative bacteria. We have identified a possible mechanism of action via the secretion of HBD-3 as a first line defence in contaminated wounds and in elective application of PRP. This finding supports a broader spectrum of clinical indications for an autologous platelet preparation.
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The formyl peptide receptor like-1 and scavenger receptor MARCO are involved in glial cell activation in bacterial meningitis
Journal of Neuroinflammation. 01/2011;
Abstract Background Recent studies have suggested that the scavenger receptor MARCO (macrophage receptor with collagenous structure) mediates activation of the immune response in bacterial infection of the central nervous system (CNS). The chemotactic G-protein-coupled receptor (GPCR) formyl-peptide... [more] Abstract Background Recent studies have suggested that the scavenger receptor MARCO (macrophage receptor with collagenous structure) mediates activation of the immune response in bacterial infection of the central nervous system (CNS). The chemotactic G-protein-coupled receptor (GPCR) formyl-peptide-receptor like-1 (FPRL1) plays an essential role in the inflammatory responses of host defence mechanisms and neurodegenerative disorders such as Alzheimer's disease (AD). Expression of the antimicrobial peptide cathelicidin CRAMP/LL-37 is up-regulated in bacterial meningitis, but the mechanisms underlying CRAMP expression are far from clear. Methods Using a rat meningitis model, we investigated the influence of MARCO and FPRL1 on rCRAMP (rat cathelin-related antimicrobial peptide) expression after infection with bacterial supernatants of Streptococcus pneumoniae (SP) and Neisseria meningitides (NM). Expression of FPRL1 and MARCO was analyzed by immunofluorescence and real-time RT-PCR in a rat meningitis model. Furthermore, we examined the receptor involvement by real-time RT-PCR, extracellular-signal regulated kinases 1/2 (ERK1/2) phosphorylation and cAMP level measurement in glial cells (astrocytes and microglia) and transfected HEK293 cells using receptor deactivation by antagonists. Receptors were inhibited by small interference RNA and the consequences in NM- and SP-induced Camp (rCRAMP gene) expression and signal transduction were determined. Results We show an NM-induced increase of MARCO expression by immunofluorescence and real-time RT-PCR in glial and meningeal cells. Receptor deactivation by antagonists and small interfering RNA (siRNA) verified the importance of FPRL1 and MARCO for NM- and SP-induced Camp and interleukin-1β expression in glial cells. Furthermore, we demonstrated a functional interaction between FPRL1 and MARCO in NM-induced signalling by real-time RT-PCR, ERK1/2 phosphorylation and cAMP level measurement and show differences between NM- or SP-induced signal transduction. Conclusions We propose that NM and SP induce glial cell activation and rCRAMP expression also via FPRL1 and MARCO. Thus the receptors contribute an important part to the host defence against infection.
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4.68Impact points
The formyl peptide receptor like-1 and scavenger receptor MARCO are involved in glial cell activation in bacterial meningitis.
Journal of neuroinflammation. 01/2011; 8(1):11.
Recent studies have suggested that the scavenger receptor MARCO (macrophage receptor with collagenous structure) mediates activation of the immune response in bacterial infection of the central nervous system (CNS). The chemotactic G-protein-coupled receptor (GPCR) formyl-peptide-receptor like-1 (FP... [more] Recent studies have suggested that the scavenger receptor MARCO (macrophage receptor with collagenous structure) mediates activation of the immune response in bacterial infection of the central nervous system (CNS). The chemotactic G-protein-coupled receptor (GPCR) formyl-peptide-receptor like-1 (FPRL1) plays an essential role in the inflammatory responses of host defence mechanisms and neurodegenerative disorders such as Alzheimer's disease (AD). Expression of the antimicrobial peptide cathelicidin CRAMP/LL-37 is up-regulated in bacterial meningitis, but the mechanisms underlying CRAMP expression are far from clear. Using a rat meningitis model, we investigated the influence of MARCO and FPRL1 on rCRAMP (rat cathelin-related antimicrobial peptide) expression after infection with bacterial supernatants of Streptococcus pneumoniae (SP) and Neisseria meningitides (NM). Expression of FPRL1 and MARCO was analyzed by immunofluorescence and real-time RT-PCR in a rat meningitis model. Furthermore, we examined the receptor involvement by real-time RT-PCR, extracellular-signal regulated kinases 1/2 (ERK1/2) phosphorylation and cAMP level measurement in glial cells (astrocytes and microglia) and transfected HEK293 cells using receptor deactivation by antagonists. Receptors were inhibited by small interference RNA and the consequences in NM- and SP-induced Camp (rCRAMP gene) expression and signal transduction were determined. We show an NM-induced increase of MARCO expression by immunofluorescence and real-time RT-PCR in glial and meningeal cells. Receptor deactivation by antagonists and small interfering RNA (siRNA) verified the importance of FPRL1 and MARCO for NM- and SP-induced Camp and interleukin-1β expression in glial cells. Furthermore, we demonstrated a functional interaction between FPRL1 and MARCO in NM-induced signalling by real-time RT-PCR, ERK1/2 phosphorylation and cAMP level measurement and show differences between NM- or SP-induced signal transduction. We propose that NM and SP induce glial cell activation and rCRAMP expression also via FPRL1 and MARCO. Thus the receptors contribute an important part to the host defence against infection.
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2.34Impact points
The role of pro-inflammatory and immunoregulatory cytokines in tendon healing and rupture: new insights.
Scandinavian journal of medicine & science in sports. 01/2011; 21(3):337-51.
Owing to limited self-healing capacity, tendon ruptures and healing remain major orthopedic challenges. Increasing evidence suggests that post-traumatic inflammatory responses, and hence, cytokines are involved in both cases, and also in tendon exercise and homeostasis. This review summarizes interr... [more] Owing to limited self-healing capacity, tendon ruptures and healing remain major orthopedic challenges. Increasing evidence suggests that post-traumatic inflammatory responses, and hence, cytokines are involved in both cases, and also in tendon exercise and homeostasis. This review summarizes interrelations known between the cytokines interleukin (IL)-1β, tumor necrosis factor (TNF)α, IL-6 and vascular endothelial growth factor (VEGF) in tendon to assess their role in tendon damage and healing. Exogenic cytokine sources are blood-derived leukocytes that immigrate in damaged tendon. Endogenous expression of IL-1β, TNFα, IL-6, IL-10 and VEGF was demonstrated in tendon-derived cells. As tendon is a highly mechanosensitive tissue, cytokine homeostasis and cell survival underlie an intimate balance between adequate biomechanical stimuli and disturbance through load deprivation and overload. Multiple interrelations between cytokines and tendon extracellular matrix (ECM) synthesis, catabolic mediators e.g. matrix-degrading enzymes, inflammatory and angiogenic factors (COX-2, PGE2, VEGF, NO) and cytoskeleton assembly are evident. Pro-inflammatory cytokines affect ECM homeostasis, accelerate remodeling, amplify biomechanical adaptiveness and promote tenocyte apoptosis. This multifaceted interplay might both contribute to and interfere with healing. Much work must be undertaken to understand the particular interrelation of these inflammatory and regulatory mediators in ruptured tendon and healing, which has relevance for the development of novel immunoregulatory therapeutic strategies.
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0.88Impact points
Complex patterns of ADAM12 mRNA and protein splice variants in the human placenta.
Annals of anatomy = Anatomischer Anzeiger : official organ of the Anatomische Gesellschaft. 01/2011; 193(2):142-8.
Trophoblast fusion in the placenta is prerequisite to successful pregnancy and the pathological conditions related to it. The presence of syncytin-1, is not sufficient to explain the complete event and ADAM12 is a major co-player candidate. Via differential splicing, the ADAM12 gene produces a short... [more] Trophoblast fusion in the placenta is prerequisite to successful pregnancy and the pathological conditions related to it. The presence of syncytin-1, is not sufficient to explain the complete event and ADAM12 is a major co-player candidate. Via differential splicing, the ADAM12 gene produces a short and a long form, being the ADAM12-S and the ADAM12-L respectively. We investigated the localisation of both variants in the human placenta using whole mount in situ hybridisation, immunohistochemistry and Northern blotting in 1st (n=8) and 3rd (n=8) trimester placentae and in the case of NB in several cell lines. In Northern blotting, 1st and 3rd trimester placentae were positive for the ADAM12-S and Bewo, 293HEK, JAR, leucocytes, macrophages, 1st and 3rd trimester placentae were positive for ADAM12-L. In whole mount in situ hybridisation, the 1st and 3rd trimester placental syncytium was positive for both variants. In immunohistochemistry, ADAM12-L localised in the cytotrophoblast of both 1st and 3rd trimester placentae, while ADAM12-S localised in the complete syncytium, often including the cytotrophoblast. The different localisation of ADAM12-S and ADAM12-L indicates a possible different role making ADAM12-L a candidate for the fusion event, while the syncytial localisation of the ADAM12-S makes it a candidate for cell-cell and cell-matrix interactions between the placental syncytium and the maternal interface.
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8.11Impact points
Role of oxidative stress in rheumatoid arthritis: insights from the Nrf2-knockout mice.
Annals of the rheumatic diseases. 12/2010; 70(5):844-50.
Increasing evidence suggests that oxidative stress may play a key role in joint destruction due to rheumatoid arthritis (RA). The aim of this study was to elucidate the role of nuclear factor erythroid 2-related factor 2 (Nrf2), a transcription factor that maintains the cellular defence against oxid... [more] Increasing evidence suggests that oxidative stress may play a key role in joint destruction due to rheumatoid arthritis (RA). The aim of this study was to elucidate the role of nuclear factor erythroid 2-related factor 2 (Nrf2), a transcription factor that maintains the cellular defence against oxidative stress, in RA. The activation status of Nrf2 was assessed in synovial tissue from patients with RA using immunohistochemistry. Antibody-induced arthritis (AIA) was induced in Nrf2-knockout and Nrf2-wild-type control mice. The severity of cartilage destruction was evaluated using a damage score. The extent of oxidative stress, the activation state of Nrf2 and the expression level of Nrf2 target genes were analysed by immunhistological staining. The expression of vascular endothelial growth factor (VEGF)-A was examined on mRNA and protein using the Luminex technique. A Xenogen imaging system was used to measure Nrf2 activity in an antioxidant response element-luciferase transgenic mouse during AIA. Nrf2 was activated in the joints of arthritic mice and of patients with RA. Nrf2-knockout mice had more severe cartilage injuries and more oxidative damage, and the expression of Nrf2 target genes was enhanced in Nrf2-wild-type but not in knockout mice during AIA. Both VEGF-A mRNA and protein expression was upregulated in Nrf2-knockout mice during AIA. An unexpected finding was the number of spontaneously fractured bones in Nrf2-knockout mice with AIA. These results provide strong evidence that oxidative stress is significantly involved in cartilage degradation in experimental arthritis, and indicate that the presence of a functional Nrf2 gene is a major requirement for limiting cartilage destruction.
Following (17)
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Nisreen Kweider
Rheinisch-Westfälische Technische Hochschule Aachen -
Ehrhardt Proksch
Christian-Albrechts-Universität Kiel -
Ulf Meyer-Hoffert
University Clinic Schleswig-Holstein, Campus Kiel -
Wolf Drescher
Universitätsklinikum Aachen -
Stephen L. Leib
University of Bern
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