No full-text available
To read the full-text of this research,
you can request a copy directly from the author.
A scarlet pimpernel for the resolution of inflammation? The role of supra-therapeutic doses of cobalamin, in the treatment of systemic inflammatory response syndrome (SIRS), sepsis, severe sepsis, and septic or traumatic shock
Abstract
Cobalamin carrier proteins,the Transcobalamins (TCS), are elevated during trauma, infections and chronic inflammatory conditions. This remains un-explained. It is proposed that such TC elevations signal a need for cobalamin central to the resolution of inflammation. Thus Cobalamin may regulate the transcription factor, NFkappaB, activation or suppression of which determines the inflammatory response and its resolution. Such regulation may involve at least 5 separate mechanisms: (i) hormone-like regulation of TNFalpha, through reduction of excess NO by cobalamin, as well as through the selective inhibition, in tandem with glutathione, of inducible nitric oxide synthase; (ii) quenching of nitric oxide radicals and reactive oxygen species, enhanced by cobalamin's glutathione sparing effect; (iii) the promotion of acetylcholine synthesis, central to the neuro-immune cholinergic anti-inflammatory pathway; (iv) the promotion of oxidative phosphorylation; (v) and a bacteriostatic role of the TCS released by neutrophil secondary granules during phagocytosis, which also appears to modulate the inflammatory response. TC elevations are dependent on NFkappaB activation, through crosstalk between NFkappaB and Sp1, another member of the helix-loop-helix protein family, which directly mediates transcription of the TCII gene. Sp1 also has binding sites on the TNFalpha and EGF gene promoters. NFkappaB may thus ensure sufficient cobalamin to determine its own eventual suppression. Cobalamin's established regulation of EGF may additionally preserve normal function of macrophages and the coagulation cascade in wound healing. By regulating NFkappaB, Cobalamin may also be the as yet unidentified mediator needed to potentiate the anti-inflammatory action of eicosanoids derived from omega-3 essential fatty acids. Moreover, animal and human clinical data suggests that high dose cobalamin may prove a promising approach to SIRS/sepsis/septic and traumatic shock.
... 44,134,138 Transcobalamin II gene polymorphisms can decrease tissue distribution of cobalamin, even with high serum cobalamin levels. 141 The 776GG homozygous variant of 776C>G polymorphism encodes a transcobalamin 2 with a lower binding affinity to vitamin B 12 , whereas polymorphisms in the FUT 6 gene (ie, rs708686, rs78060698, rs3760775, and rs7788053) elevate vitamin B 12 status. 142 It is interesting to note that polymorphisms in the ATP-binding cassette subfamily D member 4 protein will affect the transporting vitamin B 12 out of lysosomes, and thus intracellular processing of vitamin B 12 , which may increase serum levels of vitamin B 12 . ...
... 44,135 Acute uncontrolled systemic inflammation in severe COVID-19 induces sepsis and multiple organ failure, and can lead to an elevation of vitamin B 12 level due to higher levels of transcobalamins I and II, their receptors, and unsaturated B 12 binding capacity in the blood. 141,143 The inactive form of vitamin B 12 bound to transcobalamin I is the main factor that elevates blood vitamin B 12 levels. 84 However, the mechanisms by which excess vitamin B 12 is associated with sepsis remain poorly elucidated and, in these cases, supplementation with vitamin B 12 should be individually evaluated considering the aforementioned metabolic and genetic factors. ...
... Patients with severe COVID-19 have elevated levels of high mobility group box 1, 144 a potential biomarker of sepsis that is modulated by NFjB. 141 The active form of this vitamin in patients with functional transcobalamin II and normal B 12 cell metabolism can inhibit production of this biomarker by indirect mechanisms, that is, through downregulation of NFjB levels and increased acetylcholine synthesis, which positively modulates the neuro-immune cholinergic anti-inflammatory pathway. 141 Some interventional clinical trials on the effects of vitamin B 12 supplementation in combination with other micronutrients and/or medications in cases of COVID-19 are currently being recorded in the International Clinical Trials Registry Platform and ClinicalTrials.gov ...
This comprehensive review establishes the role of vitamin B12 as adjunct therapy for viral infections in the treatment and persistent symptoms of COVID-19, focusing on symptoms related to the muscle–gut–brain axis. Vitamin B12 can help balance immune responses to better fight viral infections. Furthermore, data from randomized clinical trials and meta-analysis indicate that vitamin B12 in the forms of methylcobalamin and cyanocobalamin may increase serum vitamin B12 levels, and resulted in decreased serum methylmalonic acid and homocysteine concentrations, and decreased pain intensity, memory loss, and impaired concentration. Among studies, there is much variation in vitamin B12 doses, chemical forms, supplementation time, and administration routes. Larger randomized clinical trials of vitamin B12 supplementation and analysis of markers such as total vitamin B12, holotranscobalamin, total homocysteine and methylmalonic acid, total folic acid, and, if possible, polymorphisms and methylation of genes need to be conducted with people with and without COVID-19 or who have had COVID-19 to facilitate the proper vitamin B12 form to be administered in individual treatment.
... Both mammalian B 12 -dependent enzymes, methylcobalamin-dependent methionine synthase, and adenosylcobalamin-dependent L-methylmalonyl-CoA mutase, are inhibited by NO in vitro and in vivo, 5,6 and the inhibition is attributed to the formation of NOCbl. 7 It has been postulated that cobalamins efficiently scavenge NO in vivo to form NOCbl. 7,8 Cob(II)alamin, a major intracellular form of Cbl, 9 reacts with NO at almost diffusion controlled rates to form NOCbl (k = 7.4 × 10 8 M −1 s −1 , K eq ≈ 1 × 10 8 M −1 , 25°C). 10,11 Cbls show potential in treating pathologies associated with elevated NO levels including sepsis/septic shock. ...
... 10,11 Cbls show potential in treating pathologies associated with elevated NO levels including sepsis/septic shock. 8,12 Cbls also inhibit NO-induced vasodilation 13 and NOinduced smooth muscle relaxation. 14,15 Finally, it has been proposed that NOCbl can act as a chemotherapeutic agent to treat cancer. ...
... Hamilton gastight syringes filled with the anaerobic reactant solutions in the glovebox were used to introduce the reactant solutions into the reservoir syringes of the stopped-flow instrument. Data were fitted using the program Microcal Origin version 8 HPLC Experiments. HPLC analyses were carried out in an Agilent 1100 series HPLC system equipped with a degasser, quaternary pump, autosampler, and a photodiode array detector (resolution of 2 nm). ...
Studies by others suggest that the reduced vitamin B12 complex, cob(II)alamin, scavenges nitric oxide to form air-sensitive nitroxylcobalamin (NO(-)-Cbl(III); NOCbl) in vivo. The fate of newly formed NOCbl is not known. A detailed mechanistic investigation of the oxidation of NOCbl by oxygen is presented. Only base-on NOCbl reacts with O2, and the reaction proceeds via an associative mechanism involving a peroxynitritocob(III)alamin intermediate, Co(III)-N(O)OO(-). The intermediate undergoes O-O bond homolysis and ligand isomerization to ultimately yield NO2Cbl and H2OCbl(+)/HOCbl, respectively. Ligand isomerization may potentially occur independent of O-O bond homolysis. Formation of (•)OH and (•)NO2 intermediates from O-O bond homolysis is demonstrated using phenol and tyrosine radical traps and the characterization of small amounts of a corrinoid product with minor modifications to the corrin ring.
... However, an increasing body of work suggests that Cbl may also play a central role in the regulation of immunity and inflammation (reviewed in [4]). Cbl confers significant protection in various animal models of shock, from anaphylaxis to trauma and sepsis [5–7], and has remarkable organ/tissue protective effects when used clinically for the treatment of analogous inflammation in CN poisoning (reviewed in [8]). Amongst Cbl's known immunological effects are an augmentation of the CD8+/CD4+ T-lymphocyte ratio and natural killer cell activity [9, 10], both significantly reduced in inflammatory pathology, with negative consequences in septic patients [11]. ...
... In vitro, neuronal Cbl deficiency is also associated with increased expression of two TNF-α-converting enzyme secretases [16]. A reasonable hypothesis is that such Cbl/TNF-α/IL-6 regulation may be partly effected via Cbl indirect regulation of the central immune regulatory transcription factor, nuclear factor kappa B (NF-κB) [8]. Normal physiological levels of Cbl in spinal fluid appear to correlate with NF-κB quiescence, at least, in a non-inflammatory/non-immune challenge model [17]. ...
... As there was no observable difference between the effects of alkyl and non-alkyl Cbls on NF-κB in vitro, we chose to focus these first investigations in vivo principally on HOCbl, as a clinically licensed Cbl form, known to be partially converted on cell entry to the two Cbl cofactors, MeCbl and AdoCbl, for MS and MCM, respectively [63]. Furthermore, at supraphysiological doses of 5 g i.v., HOCbl, as a clinical cyanide antidote, has shown remarkable protection against corollary inflammation (analogous to the inflammation seen in SIRS, sepsis, and septic shock), that goes beyond merely acting as a magnet for CN [8]. ...
Background. NOS/•NO inhibitors are potential therapeutics for sepsis, yet they increase clinical mortality. However, there has been no in vivo investigation of the (in vitro) •NO scavenger, cobalamin's (Cbl) endogenous effects on NOS/•NO/inflammatory mediators during the immune response to sepsis. Methods. We used quantitative polymerase chain reaction (qPCR), ELISA, Western blot, and NOS Griess assays, in a C57BL/6 mouse, acute endotoxaemia model. Results. During the immune response, pro-inflammatory phase, parenteral hydroxocobalamin (HOCbl) treatment partially inhibits hepatic, but not lung, iNOS mRNA and promotes lung eNOS mRNA, but attenuates the LPS hepatic rise in eNOS mRNA, whilst paradoxically promoting high iNOS/eNOS protein translation, but relatively moderate •NO production. HOCbl/NOS/•NO regulation is reciprocally associated with lower 4 h expression of TNF-α, IL-1β, COX-2, and lower circulating TNF-α, but not IL-6. In resolution, 24 h after LPS, HOCbl completely abrogates a major late mediator of sepsis mortality, high mobility group box 1 (HMGB1) mRNA, inhibits iNOS mRNA, and attenuates LPS-induced hepatic inhibition of eNOS mRNA, whilst showing increased, but still moderate, NOS activity, relative to LPS only. experiments (LPS+D-Galactosamine) HOCbl afforded significant, dose-dependent protection in
mice Conclusions. HOCbl produces a complex, time- and organ-dependent, selective regulation of NOS/•NO during endotoxaemia, corollary regulation of downstream inflammatory mediators, and increased survival. This merits clinical evaluation.
... Similarly, vitamin B 12 is a cofactor for converting methylmalonyl-CoA to succinyl-CoA, thus proving a necessity for odd-chain fatty acid and amino acid metabolism [2]. Furthermore, the central cobalt moiety in the vitamin B 12 corrin ring scavenges cyanide ions and reactive oxygen species (ROS) [11][12][13][14]. Folate and vitamin B 12 overlap in function during the regeneration of methionine from homocysteine in a reaction catalyzed by methionine synthase [15]. ...
... As such, we took plasma samples from patients previously confirmed to be MAP-negative or MAP-positive via IS900 PCR and compared their folate and B12 levels via ELISA. We found that average MAP-positive plasma folate levels were significantly reduced to 14 Figure 1B]. Since the plasma samples were collected from two subsets of CD patients, these results indicate that the risk of malabsorptive folate and B12 deficiency may be correlated particularly with MAP infection in CD patients. ...
Folate and vitamin B12 deficiency is highly prevalent among Crohn’s disease (CD) patients. Furthermore, CD pathology can be mediated by Mycobacterium avium subsp. paratuberculosis (MAP) infection. However, the direct effect of folate (B9) and cobalamin (B12) deficiency during MAP infection remains uncharacterized. This study investigates how folate and B12 deficiency impedes macrophage apoptosis and exacerbates the inflammation in macrophages infected with MAP isolated from CD patients. Accordingly, we measured folate and B12 in ex vivo plasma samples collected from CD patients with or without MAP infection (N = 35 per group). We also measured the expression of the pro-inflammatory cytokines IL-1β and TNF-α, cellular apoptosis and viability markers, and bacterial viability in MAP-infected macrophages cultured in folate and B12 deficient media. We determined that MAP-positive CD patients have significantly lower plasma folate and B12 in comparison to MAP-negative CD patients [414.48 ± 94.60 pg/mL vs. 512.86 ± 129.12 pg/mL, respectively]. We further show that pro-inflammatory cytokines IL-1β and TNF-α are significantly upregulated during folate and vitamin B12 deprivation following MAP infection by several folds, while supplementation significantly reduces their expression by several folds. Additionally, depletion of folate, B12, and folate/B12 following MAP infection, led to decreased macrophage apoptosis from 1.83 ± 0.40-fold to 1.04 ± 0.08, 0.64 ± 0.12, and 0.45 ± 0.07 in folate-low, B12-low, and folate/B12-low cells, respectively. By contrast, folate and folate/B12 supplementation resulted in 3.38 ± 0.70 and 2.58 ± 0.14-fold increases in infected macrophages. Interestingly, changes in overall macrophage viability were only observed in folate-high, folate/B12-high, and folate/B12-low media, with 0.80 ± 0.05, 0.82 ± 0.02, and 0.91 ± 0.04-fold changes, respectively. Incubation of Caco-2 intestinal epithelial monolayers with supernatant from infected macrophages revealed that folate/B12 deficiency led to increased LDH release independent of oxidative stress. Overall, our results indicate that folate and B12 are key vitamins affecting cell survival and inflammation during MAP infection.
... [116][117][118][119] These key effects include (i) selective inhibition of iNOS and reduction of NO, (ii) decreased production of ROS through glutathione-sparing effects, (iii) increased synthesis of acetylcholine and enhancement of the cholinergic antiinflammatory pathway, (iv) stimulation of oxidative phosphorylation, (v) enhancement of bacteriostasis, and (vi) control of nuclear factor-kappa B activation. 118,120 In addition, vitamin B 12 exerts anti-vasoplegic effects through the binding of hydrogen sulfide (an endogenous vasodilator) and is associated with decreased vasopressor requirements in multiple case reports. 121 However, despite the existing evidence and its theoretical advantages, the benefits of vitamin B 12 have not been tested in prospective clinical trials. ...
... Some experts have called for broader testing of vitamin B 12 in sepsis, arguing that large parenteral doses have historically been well tolerated when used for cyanide poisoning. 118,120 However, vitamin B 12 levels have been positively correlated with increased inflammatory markers, higher organ dysfunction scores, and increased mortality in observational studies. 2,116 While this may point at a possible role of vitamin B 12 as an acute-phase reactant, it seems counterintuitive to administer additional vitamin B 12 given these findings. ...
Vitamins are essential micronutrients with key roles in many biological pathways relevant to sepsis. Some of these relevant biological mechanisms include antioxidant and anti-inflammatory effects, protein and hormone synthesis, energy generation, and regulation of gene transcription. Moreover, relative vitamin deficiencies in plasma are common during sepsis and vitamin therapy has been associated with improved outcomes in some adult and pediatric studies. High-dose intravenous vitamin C has been the vitamin therapy most extensively studied in adult patients with sepsis and septic shock. This includes three randomized control trials (RCTs) as monotherapy with a total of 219 patients showing significant reduction in organ dysfunction and lower mortality when compared to placebo, and five RCTs as a combination therapy with thiamine and hydrocortisone with a total of 1134 patients showing no difference in clinical outcomes. Likewise, the evidence for the role of other vitamins in sepsis remains mixed. In this narrative review, we present the preclinical, clinical, and safety evidence of the most studied vitamins in sepsis, including vitamin C, thiamine (i.e., vitamin B1), and vitamin D. We also present the relevant evidence of the other vitamins that have been studied in sepsis and critical illness in both children and adults, including vitamins A, B2, B6, B12, and E.
Vitamins are key effectors in many biological processes relevant to sepsis.
We present the preclinical, clinical, and safety evidence of the most studied vitamins in pediatric sepsis.
Designing response-adaptive platform trials may help fill in knowledge gaps regarding vitamin use for critical illness and association with clinical outcomes.
... cob(II)alamin [4], and nitric oxide ( · NO) for which k = 7.4 × 10 8 M −1 s −1 and K NO ≈ 1 × 10 8 M −1 at 25 °C [5][6][7]. It has been postulated that cobalamins show the potential to eliminate excess · NO from organisms [8,9] since the Co III -NO − complex can be protonated at neutral pH to form Co III -NOH, which in turn can undergo aquation to release HNO. The latter species is known to dimerize and decompose to water and gaseous N 2 O in aqueous solution [10]. ...
... Reactions (5)- (9) can account for the reformation of nitrite and CblNO 2 , as well as the overall depletion of ascorbic acid from the solution over longer reaction times. ...
Despite detailed studies on nitroxylcobalamin (CblNO) formation, the possible intracellular generation of CblNO via reduction of nitrocobalamin (CblNO2) remains questionable. To study this further, spectroscopic studies on the reaction of CblNO2 with the intracellular antioxidant ascorbic acid (HAsc⁻) were performed in aqueous solution at pH < 5.0. It was found that nitroxylcobalamin is the final product of this interaction, which is not just a simple reaction but a rather complex chemical process. We clearly show that an excess of nitrite suppresses the formation of CblNO, from which it follows that ascorbic acid cannot reduce coordinated nitrite. We propose that under the influence of ascorbic acid, nitrocobalamin is reduced to Cbl(II) and nitric oxide (·NO), which can subsequently react rapidly to form CblNO. It was further shown that this system requires anaerobic conditions as a result of the rapid oxidation of both Cbl(II) and CblNO.
Graphical Abstract
Electronic supplementary material
The online version of this article (10.1007/s00775-018-1540-1) contains supplementary material, which is available to authorized users.
... Cbl supplementation is also beneficial in treating many inflammatory diseases and there is accumulating evidence that Cbl can provide protection in oxidative stress-associated pathologies (77, 132-135, 137, 265). Levels of the Cbl transport protein TC have also been shown to be elevated during inflammation (266)(267)(268) concomitant with NF-κB activation (137), which is induced by various stimuli, including ROS. Taken together, these studies suggest a potential role for Cbl in the regulation of inflammatory processes (125,137). ...
... Levels of the Cbl transport protein TC have also been shown to be elevated during inflammation (266)(267)(268) concomitant with NF-κB activation (137), which is induced by various stimuli, including ROS. Taken together, these studies suggest a potential role for Cbl in the regulation of inflammatory processes (125,137). ...
Cobalamins (vitamin B12 derivatives) are essential cofactors for two enzymes in mammals: cytosolic methionine synthase and mitochondrial methylmalonyl-CoA mutase. In addition to its function as cofactor, a further role as a modulator of inflammatory and immune processes has been suggested for vitamin B12. Vitamin B12 deficiency is a major health problem in the US population, especially amongst the elderly. The vascular endothelium lacks the transsulfuration pathway and hence, relies solely on the B12-dependent methionine synthase to metabolize homocysteine. Thus, vitamin B12 deficiency is the primary modifiable cause of hyperhomocysteinemia, a risk factor for cardiovascular disease, in the post folate fortification era. Although vitamin B12 has been studied for over half a century, there remains much to be discovered regarding the biochemical pathways that lead to the synthesis of the cobalamin cofactors and the potential roles of vitamin B12 beyond its function as cofactors of methionine synthase and methylmalonyl-CoA mutase. This research project has been designed to shed light on the key intermediates required for the metabolism of B12 in human cardiovascular cells and the effects of B12 status on vascular pathophysiology, independent of its actions as an enzymatic cofactor.
... It has principle roles in the treatment of different pathological conditions. Vitamin B 12 has anti-inflammatory, immunomodulatory, antioxidant and antioxidative stress potential actions (Miller, 2002, Wheatley;2006, Scalabrino et al., 2008. Cbl therapy normalizes levels of TNF-α and epidermal growth factor in Cbl-deficient patients (Scalabrino et al., 2008). ...
... This beneficial impact obtained by the used vitamins may attribute to their abilities to protect and stabilize cellular membranes by manipulating the ZnO toxicity. The anti-toxic and protective effects of B vitamins was previously documented (Wheatley, 2006 ;Mehta et al., 2008Mehta et al., , 2011. ...
The protective effect of B vitamins combination against zinc oxid bulk (ZnO-bulk) and its nanparticles (ZnO-NPs) toxicity-induced kidney damage in rats was investigated. ZnO-bulk or its NPs were administered orally (500 mg /kg body weight) for 10 consecutive days. The results revealed that oral co-ingestion of of B vitamins combination (250 mg B 3 , 60 mg B 6 and 0.6 mg B 12 / Kg body weight) daily for 3 weeks to rats intoxicated by either ZnO-bulk or its NPs markedly ameliorated increases in serum markers of kidney function, including uric acid and creatinine. Also the used vitamins in combination down-modulated ZnO caused dramatic increases in serum pro-inflammatory biomarkers including, tumor necrosis factor-α (TNF-α), and C-reactive protein (CRP) as well as in serum vascular endothelial growth factor (VEGF) (angiogenic factor) in intoxicated rats compared with intoxicated untreated ones. In addition, the result showed that B vitamins effectively ameliorated the increased malondialdehyde (MDA, a major product of lipid peroxidation), the decrease in antioxidant enzyme, glutathione peroxidase (GPx), oxidative deoxyribonucleic acid (DNA) damage and the increase in the apoptosis marker caspase 3 in kidneys of intoxicated rats with either ZnO-bulk or its NPs compared with intoxicated untreated.In conclusion, prophylactic treatment with the current used B vitamins in combination may be beneficial in protecting kidney tissue from the toxic impact of ZnO-bulk or its NPs. [Jehad M. Yousef. Potential prophylactic impact of B vitamins against zinc oxide bulk and its nanoparticles induced kidney damage. Life Sci J 2014;11(8):729-738]. (ISSN:1097-8135). http://www.lifesciencesite.com. 108
... It has fundamental therapeutic roles in the treatment of different pathological conditions. Cbl ingestion is potential in treating many inflammatory diseases, prophylaxis against oxidative stress-associated pathologies (Miller, 2002;Wheatley, 2006) and modulating the immune response (Scalabrino et al., 2008). Cbl therapy ameliorates levels of TNF-α and epidermal growth factor in Cbl-deficient patients (Scalabrino et al., 2008). ...
... The positive response obtained by the used vitamin B complex may attribute to their ability to protect and stabilize cellular membranes by manipulating the ZnO toxicity. The anti-toxic and the hepato-protective effects of B vitamins were previously reported (Wheatley, 2006, Chen et al., 2008, Mehta et al., 2008. ...
The aim of this work is to explore the protective of B vitamins (B3, B6 and B12) against the hepatotoxic potency of either bulk zinc oxide (ZnO-bulk) or its nanoparticles (ZnO-NPs)-induced liver damage in rats. ZnO- bulk or its NPs were administered orally (500 mg/kg b.w.) for 10 successive days. The results revealed that oral co-administration of combination of B vitamins (250 mg B3, 60 mg B6 and 0.6 mg B12/Kg body weight) daily for 3 weeks to rats intoxicated by either ZnO- bulk or its NPs markedly ameliorated increases in serum of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and lactate dehdrogenase (LDH). The B vitamins also down-regulated increases in serum glucose level as well as increases in immuno-inflammatory biomarkers, including tumor necrosis factor-α (TNF-α) and C-reactive protein compared with intoxicated, untreated rats. Beside, the used agent successfully modulated the alterations in serum vascular endothelial growth factor (VEGF), attenuated liver oxidative DNA damage compared with ZnO intoxicated groups. We showed that the used B complex mitigated increased malondialdehyde (MDA), decrease in glutathione peroxidase (GPx) and increase in the apoptosis marker caspase 3 of liver tissue in response to either ZnO-bulk or its NP toxicity. In conclusion, early treatment with vitamin B complex may protect liver tissue from deleterious damage induced by the toxic effects of ZnO-bulk or its NPs.
... The relationship between Vitamin B12 levels and the pathogenesis of urticaria is not fully understood, although the micronutrient is thought to regulate the release of cytokines after mast cell degranulation through its immunomodulatory properties. 23 In the present study, Vitamin B12 levels were below normal laboratory parameters in 40.8% (n = 116) of the cases. We think that this rather high number is due to the low socioeconomic status and dietary habits of our region. ...
Background:
Acute urticaria and angioedema are emergency dermatological conditions associated with various etiologic factors.
Objective:
To determine the etiological causes in patients with acute urticaria and angioedema, and to investigate whether more than one etiological cause was present, along with the patients' laboratory values.
Methods:
The study was conducted in a tertiary hospital with one center. Etiological causes and laboratory parameters in 284 patients diagnosed with acute urticaria and angioedema were retrospectively studied.
Results:
A total of 284 patients were included in the study. The mean age of the patients was 42.7 ± 15.6 years, where 163 (57.4%) were women and 121 (42.6%) were men. Acute urticaria and angioedema occurred together in 149 (52.5%) patients. At least one precipitating factor among the predisposing risk factors was present in 220 (77.5%) patients, and more than one precipitating factor was found in 51 (18%) patients. Medication use was found in 157 (55.3%) patients and infection in 54 (19%). The development of urticaria after food consumption was noted in nine (3.2%) individuals. A history of infection and medication intake was present in 50 (17.6%) patients. A joint history of food consumption and medication intake was present in only one patient. Elevated C-reactive protein level was found in 178 (62.7%) patients and elevated anti-streptolysin O titer in 41 (14.4%) patients. Vitamin B12 deficiency was found in 116 (40.8%) patients and vitamin D deficiency in 254 (89.4%).
Conclusion:
Acute urticaria and angioedema may occur as a result of multiple etiological factors, in which different triggers may be present simultaneously.
... The result of this study clearly showed excess ROS generation and reduced GSH content by PQ administration in the midbrain that was returned to the normal rates by vit B12 treatment. Research has shown that vit B12 plays a protective role against elevated superoxide levels and preserves GSH content in the reduced state (86,87). In our previous study, vit B12 administration could prevent the neurotoxicity of methamphetamine in the striatum and cortex regions of the mouse brain via an increase in GSH level and decreased apoptotic index (88). ...
Objectives:
The goal of this study was to evaluate the neuroprotective effects of vit B12 on paraquat-induced neurotoxicity.
Materials and methods:
Thirty-six male mice were randomly divided into six groups. Three groups were treated intraperitoneally with paraquat (10 mg/kg) twice a week (with a 3-day interval) for 3 weeks. Normal saline, vit B12 (1 mg /kg), or vit C (50 mg/kg) was injected 30 min before paraquat administration. Other groups only received normal saline (control), vit B12, or vit C in the same protocol. Motor performance and coordination were assayed by challenging beam traversal, pole, open field, and rotarod tests. The hippocampus and serum samples were isolated to evaluate the oxidative stress (GSH and ROS), apoptosis (caspase 3), and inflammatory markers (TNF-α and IL-1β).
Results:
Administration of paraquat leads to induction of motor deficits, which were improved by treatment with vit B12. In addition, vit B12 could prevent oxidative damage, apoptosis, and inflammation caused by paraquat.
Conclusion:
It seems that vit B12 could be a novel therapeutic agent in the management of paraquat induced-neurotoxicity.
... When vitamin B12 levels are insufficient, demyelination and degeneration occur in the nervous system, leading to conditions such as optic atrophy, anosmia, glossitis, paresthesia, and cognitive defects [99]. Vitamin B12 regulates growth factors, macrophage function, and the coagulation system, thus, highlighting the potential of vitamin B12 in alleviating severe inflammatory conditions [100]. Vitamin B12 is also an antioxidant [101]. ...
Although facial nerve palsy is not a life-threatening disease, facial asymmetry affects interpersonal relationships, causes psychological stress, and devastates human life. The treatment and rehabilitation of facial paralysis has many socio-economic costs. Therefore, in cases of facial paralysis, it is necessary to identify the cause and provide the best treatment. However, until now, complete recovery has been difficult regardless of the treatment used in cases of complete paralysis of unknown cause and cutting injury of the facial nerve due to disease or accident. Therefore, this article aims to contribute to the future treatment of facial paralysis by reviewing studies on drugs that aid in nerve regeneration after peripheral nerve damage.
... TCN1 encodes a member of the vitamin B 12 -binding protein family, transcobalamin I, which is elevated during infectious conditions. As a member of the cobalamin transport protein, transcobalamin elevation may contribute to the resolution of inflammation [21]. FOLR3 and GGH are associated with the folate pathway. ...
Sepsis remains a major global concern and is associated with high mortality and morbidity despite improvements in its management. Markers currently in use have shortcomings such as a lack of specificity and failures in the early detection of sepsis. In this study, we aimed to identify key genes involved in the molecular mechanisms of sepsis and search for potential new biomarkers and treatment targets for sepsis using bioinformatics analyses. Three datasets (GSE95233, GSE57065, and GSE28750) associated with sepsis were downloaded from the public functional genomics data repository Gene Expression Omnibus. Differentially expressed genes (DEGs) were identified using R packages (Affy and limma). Functional enrichment of the DEGs was analyzed with the DAVID database. Protein-protein interaction networks were derived using the STRING database and visualized using Cytoscape software. Potential biomarker genes were analyzed using receiver operating characteristic (ROC) curves in the R package (pROC). The three datasets included 156 whole blood RNA samples from 89 sepsis patients and 67 healthy controls. Between the two groups, 568 DEGs were identified, among which 315 were upregulated and 253 were downregulated in the septic group. These genes were enriched for pathways mainly involved in the innate immune response, T-cell biology, antigen presentation, and natural killer cell function. ROC analyses identified nine genes-LRG1, ELANE, TP53, LCK, TBX21, ZAP70, CD247, ITK, and FYN-as potential new biomarkers for sepsis. Real-time PCR confirmed that the expression of seven of these genes was in accordance with the microarray results. This study revealed imbalanced immune responses at the transcriptomic level during early sepsis and identified nine genes as potential biomarkers for sepsis.
... Deficiency of folate (vitamin B9), which is important for the start-up synthesis of mitochondrial protein glycine, inhibits the formation of ATP and the synthesis of DNA. Insufficient supplementation of cobalamin (vitamin B12) plays a crucial role in hematopoiesis, by regulating NF-kB, through the inhibition of inducible NOS [70,71]. Ascorbic acid (vitamin C, cofactor for catecholamines synthesis that is involved in the biosynthesis of carnitine-stimulating carbohydrates oxidation and energy generation) is crucial for healthy cellular life. ...
Micro nutrients (minerals and vitamins), as well as macro nutrients (proteins, fats, and carbohydrates) which are crucial substrates/co-factors in the metabolic pathways regulating DNA synthesis/repair and gene expression, are totally necessary for the optimal health, vital for growth, normal development of organs, body at whole, proper immune function, restoring resistance to infections, and can significantly affect cell growth, tissue differentiation, cancer incidence, aging and homeostasis. Dis balance in nutrients supplementation leads to genomic instability, compromises normal function of cellular pathways and triggers development of chronic diseases. Micro nutrients play vital roles in functional integrity of the body physical barriers which are associated with natural defence antimicrobial s, including interferons (IFNs), phagocytes, and NK cells, which are crucial in regulation of the inflammatory process.
During the viral infestation, most viruses manipulate the host cell’s metabolism to optimize the bio-synthetic needs, affecting cross talk between the immune system and central metabolism. Also, nutritional deficiency affects not only the hosts vital functions, but also the invading viral pathogen. The main deficits discovered during the viral infection usually include micro nutrient and macro nutrient abnormalities, such as reduced level of several vitamins, minerals, trace elements, amino acids including cysteine, tripeptide and others. These deficiencies can promote and strengthen viral parthenogenesis by weakening the immune system of the host, making it prone to development secondary infections. Specific micro nutrients can inhibit viral infection at various stages of the viral life cycle, that include blocking virus entry and virus multiplication, blocking virus activation in latently infected cells and prevents virus spread. Viral pathogens, such as COIVD-19, SARS, MERS and influenza can cause a massive “cytokine storm”, which triggers acute respiratory and multiple organ dysfunction, with following physiological deterioration and can lead to sudden death in several individuals. Proper supplementation with specific micro- and macro nutrients was found to suppress pro-inflammatory cytokines, increase anti-inflammatory cytokines and can contribute to balancing function of cellular inflammatory pathways during the onset and development of the viral infections.
The main aim of this Chapter is to demonstrate an importance and mechanism of micro- and macro nutrients contribution to development of a potential inhibition of viral parthenogenesis, as well as suggest the specific types of functional food which can accompany micro- and macro nutrients supplementation during viral diseases prevention and maintenance.
... In agreement these, previous studies had been shown considerable effects of cobalamin on inflammation through the regulation of NF-kB. According to the important effect of NF-kB on gene expression of pro and anti-inflammatory factors, preventing effects of cobalamin on neuronal cell loss might be explained (Wheatley, 2006). Studies also had shown significant inverse linear relationship between cobalamin and TNF-α levels which is important during the neuroinflammation induced apoptosis (Hajihashemi et al., 2017). ...
Introduction: Cobalamin (vitamin B12) is essential for metabolism of the nervous system and its supplementation attenuate neuropathic and neuroinflammatory diseases. We designed to investigate the neuroprotective effects of cobalamin against the trimethyltin chloride (TMT) induced structural and functional damages in the hippocampus.
Methods: Adult male Wistar rats were divided into four groups: 1) control: received saline; 2) TMT: received a single dose of TMT (8mg/kg; ip) to induce hippocampal damages; 3) cobalamin: received cobalamin (18mg/kg; ip) for five consecutive days and 4) TMT+cobalamin: received single ip injection of TMT then were treated with cobalamin for five consecutive days. In day six of the experiments, behavioral effects of TMT and cobalamin were evaluated through shuttle box and novel object recognition task. After the behavioral tests, animals were perfused transcardially and Nissl staining was used on hippocampus to assess neural cell damages.
Results: Novel object exploring time was significantly decreased in TMT treated rats and treatment with cobalamin after TMT injection significantly recompensed this effect of TMT. In passive avoidance, TMT significantly decreased latency to enter the dark box, while cobalamin administration after the TMT injection significantly abolished this effect of TMT. Neural cell counted in the areas of hippocampus was significantly decreased in the TMT group and cobalamin treatment after the TMT injection significantly prevented neural cell loss.
Conclusion: These results indicate a neuroprotective role for cobalamin against the TMT induced memory impairment and hippocampal neuronal loss.
... It is able to inhibit nitric oxide production, intracellular oxidative stress and cellular apoptosis (33). Interestingly, it has been reported that vit B 12 can preserve GSH status and the thiol groups of enzymes in the reduced state (34). Our findings confirmed that oxidative stress plays an important role in METH neurotoxicity and antioxidant agent like vit B 12 can prevent the neurotoxic effect of METH and increase the GSH level. ...
Objective(s)
Methamphetamine (METH) is a powerful stimulant drug that directly affects the brain and induces neurological deficits. B12 is a water-soluble vitamin (vit) that is reported to attenuate neuronal degeneration. The goal of the present study is to investigate the effect of vitamin B12 on METH’s neurodegenerative changes.
Materials and Methods
Two groups of 6 animals received METH (10 mg/kg, interaperitoneally (IP)) four times with a 2 hr interval. Thirty mins before METH administration, vit B12 (1 mg/kg) or normal saline were injected IP. Animals were sacrificed 3 days after the last administration. Caspase proteins levels were measured by Western blotting. Also, samples were examined by TUNEL assay to detect the presence of DNA fragmentation. Reduced glutathione (GSH) was also determined by the Ellman method.
Results
The pathological findings showed that vit B12 attenuates the gliosis induced by METH. Vit B12 administration also significantly decreased the apoptotic index in the striatum and the cerebral cortex (P<0.001). It also reduced caspase markers compared to the control (P<0.01 and P<0.001, respectively). Interestingly, co-administration of METH and Vit B12 elevates the levels of GSH in both regions of the brain and returned it to normal levels compared to the METH group.
Conclusion
The current study suggests that parenteral vit B12 at safe doses may be a promising treatment for METH-induced brain damage via inhibition of neuron apoptosis and increasing the reduced GSH level. Research focusing on the mechanisms involved in the protective responses of vit B12 can be helpful in providing a novel therapeutic agent against METH-induced neurotoxicity.
... Education has long been recognised as the means to achieving change. Education helps in creating new ideas and initiative that move a country towards increasing prosperity [4,5]. Higher education also serves as the means of securing attractive job. ...
... The tubular and/or epithelial areas were more reduced in the animals from Bu + 7dS and Bu + 7dB 12 than Bu-6d due to the fact that the animals were killed 13 days after the last injection of Bu, being exposed for a longer period of time to this antineoplastic drug than the animals from Bu-6d. Oxidative stress and cell death have been correlated with reduced levels of glutathione, a major antioxidant defense molecule [65], and an important function of vitamin B 12 (cobalamins) is to maintain glutathione status and the sulphydryl groups of enzymes at a reduced state [66]. Cobalamins (especially thiolatocobalamins), maintain the intracellular glutathione levels, prevent peroxide-induced oxidative stress and avoid cell death, including apoptosis and necrosis [67]. ...
Busulphan (Bu), an alkylating agent used for bone marrow and spermatogonial stem cell transplantation (SSCT), impairs Sertoli (SC) cells, which are necessary for the spermatogonial stem cell (SSC) homing during transplantation. As Leydig (LC) and peritubular myoid (PMC) cells are essential for SC support and maintenance of spermatogonial niche, we evaluated the impact of Bu on the LC and PMC structural integrity. Vitamin B12 (B12) has demonstrated beneficial effects against drug-induced testicular changes; thus, we also examined whether this vitamin is able to stimulate spermatogonia mitotic activity and prevent Bu-induced germ cell death. Rats received 10mg/kg of Bu in the 1st and 4th days, and daily B12 supplementation during Bu treatment and for 6days after the last injection of Bu (Bu-6d), totaling 10days of treatment. Other animals received the same treatment as Bu-6d, and B12 supplementation (Bu+7dB12) or saline (Bu+7dS) for 7 more days, totaling 17days of treatment. Serum testosterone levels were measured. In the historesin-embedded testis sections, the seminiferous tubule and epithelial areas were measured, and the number of spermatogonia and PMC was quantified. Actin and 17β-HSD6 immunofluorescence was detected, and the number of TUNEL-positive LC and germ cells was computed. In Bu-6d, PMC number reduced, and a weak actin immunoexpression and death in these cells was observed. The testosterone levels reduced, and the interstitial tissue showed a weak 17β-HSD6 immunoexpression and increased number of TUNEL-positive LC. In Bu+7dB12, the number of spermatogonia was higher than in Bu-6d and Bu+7dS, and the number of TUNEL-positive germ cells was significantly lower than in Bu+7dS. Bu exerts a harmful impact on PMC and LC, reducing the testosterone levels. Vitamin B12 prevents significantly Bu-induced germ cell death and stimulates spermatogonia proliferation, being a useful strategy for the enrichment of SSC in vitro and an adjuvant therapy for spermatogenesis recovery in oncologic patients.
... 25,26 Another report has indicated that vitamin B 12 may regulate nuclear factor kappa B (NFκB), which is transcription regulator activated by cytokines like TNF-α, and it determines cell survival and apoptosis. 27,28 These reports suggest that vitamin B 12 plays the role of a modulator for cytokine expression in the injured liver where the vitamin B 12 storage has diminished. ...
Background:
Vitamin B12 is stored primarily in the liver, and highly elevated serum vitamin B12 levels occur in acute hepatitis and severe alcoholic liver disease. We evaluated the relationship between vitamin B12 levels and liver disease severity and long term prognosis in patients with chronic viral hepatitis and cirrhosis.
Methods:
We enrolled 90 patients (57 men, 33 women) with chronic viral hepatitis and cirrhosis who admitted to our hospital as a prospective cohort study. Overall, 37 patients had chronic hepatitis and 53 had cirrhosis (Child-Pugh A 33, B 13, and C 7); 57 patients had primary liver cancer. Serum vitamin B12 concentration and holotranscobalamin (holoTC) II (active form of vitamin B12) were determined and followed prospectively for at least 5 years.
Results:
Mean total serum vitamin B12 concentration was significantly higher in Child-Pugh C (1308 ± 599 pg/mL) compared to those with chronic hepatitis (655 ± 551 pg/mL), Child-Pugh A (784 ± 559 pg/mL), and Child-Pugh B (660 ± 464 pg/mL) (P = 0.036) Presence of primary liver cancer also influenced serum vitamin B12 levels [657 (167-2956) vs. 432 (189-2956); P = 0.015]. Patients were divided into quartiles by vitamin B12 level. Patients without primary liver cancer in quartile 4 (≥ 880 pg/mL) demonstrated significantly poorer prognosis than those in quartiles 1-3 (< 880 pg/mL) (P = 0.023). The percentage of holohaptocorrin (holoHC) [(total vitamin B12 - holoTC II) × 100] was significantly higher in Child-Pugh B and C 86 (80-87)% than chronic hepatitis and Child-Pugh A 77 (31-89)% (P = 0.006) Multivariate analysis indicated serum vitamin B12 levels (HR = 1.001, P = 0.029) as a prognostic factor.
Conclusion:
Falsely elevated serum vitamin B12 levels mainly composed of increased holoHC were associated with severity (Child-Pugh C and primary liver cancer) and prognosis in chronic viral liver disease.
... Vitamin B12 is also required for the isomerisation of d-leucine to leucine which is found in certain regulatory proteins like transcription factors NF-ĸB (nuclear factor kappa-light-chain-enhancer of activated B cells), Myc and Fos. Vitamin B12 may therefore have a secondary oncogene role 7 . ...
Vitamin B12 is an essential micronutrient, as humans have no capacity to produce the vitamin and it needs to be ingested from animal proteins. The ingested Vitamin B12 undergoes a complex process of absorption and assimilation. Vitamin B12 is essential for cellular function. Deficiency affects 15% of patients older than 65 and results in haematological and neurological disorders. Low levels of Vitamin B12 may also be an independent risk factor for coronary artery disease. High levels of Vitamin B12 are associated with inflammation and represent a poor outlook for critically ill patients. Treatment of Vitamin B12 deficiency is simple, but may be lifelong.
... (Solomon, 2007). Cobalamins have fundamental therapeutic roles in the treatment of different diseases, including many inflammatory diseases, oxidative stress-associated pathologies (Miller, 2002;Wheatley, 2006, Scalabrino et al., 2008, immune response disorder (Scalabrino et al., 2008), and toxicity (Mitra et al., 2004). Vitamin B12 also demonstrated a multitude of protective strategies that included antioxidant, ROS quenching, metal ion chelating and carbonyl scavenging activities (Mehta et al., 2008;Moreira et al., 2011). ...
The aim of this study is to investigate the protective role of a combination of B vitamins (B3, B6 and B12) against the cardiotoxic impact of either bulk zinc oxide (ZnO-bulk) or its nanoparticles (ZnO-NPs)-induced cardiac infarction. ZnO-bulk and ZnO-NPs ( <100 nm) were administered orally at 500mg/kg body weight for 10 consecutive days. The results revealed that co-administration of a combination of B vitamins (250 mg B3, 60 mg B6 and 0.6 mg B12/Kg body weight) daily for 3 weeks to rats intoxicated by either ZnO-bulk or ZnO-NPs markedly ameliorated increases in serum markers of cardiac infarction, including troponin T, creatine kinase-MB (CK-MB), aspartate aminotransferase (AST) and lactate dehdrogenase (LDH), as well as increases in proinflammatory biomarkers, including tumor necrosis factor-alpha (TNF-alpha), and C-reactive protein (CRP) and vascular endothelial growth factor (VEGF), compared with intoxicated untreated rats. The B vitamins could also modulate the alterations in cardiac DNA damage, malondialdehyde (MDA), glutathione peroxidase (GPx) and caspase 3 in response to either ZnO- bulk or ZnO-NPs toxicity. In conclusion, early treatment with the used combination of B vitamins may protect cardiac tissue from damaging toxic impact of ZnO-bulk or ZnO-NPs.
... Similar observations were observed in two clinical trials [39][40] , though duration of supplementations were much longer (2month & 6 month) & they also administered vitamin B 6 along with these two vitamins. Although mechanism of this decrement of inflammation can't be elucidated from our study, decreased production of TNF-α, IL-6, IL-8, CRP, free radicals or NF-κ B by the inflammatory cells are proposed as mechanism for their anti-inflammatory effects by several researchers [41][42][43][44][45][46][47] . ...
p> Background : Vitamin B<sub>12</sub> & Folic acid (FA) are used with other B vitamins to relieve various painful and inflammatory conditions. But combined effects of vitamin B<sub>12</sub> & FA on nociceptive pain, inflammatory pain and inflammation are yet to be clearly demonstrated.
Objective: To assess the effectiveness of short term daily administration of B<sub>12</sub> & FA on reducing pain and inflammation.
Methods: This prospective experimental study was conducted in the Department of Physiology, Bangabandhu Sheikh Mujib Medical University (BSMMU), Shahbag, Dhaka from 1<sup>st</sup> January 2011 to 30<sup>th</sup> June 2012. For this purpose, 12 male Long Evans rats, weighing 200 to 250 grams were collected from the animal house of BIRDEM, Shahabag, Dhaka. All the rats received a daily intraperitoneal injection of either combination of B<sub>12</sub> (15mg/kg) & FA (5mg/kg) or equal volume of normal saline for 7 consecutive days. To evaluate the effects on pain, tail immersion test for nociceptive pain and formalin test for nociceptive & inflammatory pain were done. In addition, to evaluate their effects on inflammation formalin induced hind paw oedema was measured.
Results: Combination of B<sub>12</sub> & FA Supplementation significantly lowered the variables for inflammatory pain & inflammation.
Conclusion: This study revealed that, combined short term daily supplementation of B<sub>12</sub> & FA is effective in lowering inflammatory pain & inflammation.
Bangladesh Crit Care J March 2015; 4 (1): 33-37</p
... However, in the present study, we found that diabetic vegetarians had a significantly lower vitamin B-12 status, which might be related to an increase the levels of oxidative stress and inflammation. Vitamin B-12 could potentially be a useful antioxidant, because it can stimulate methionine synthase activity and direct reaction with reactive oxygen and nitrogen species, and through a glutathione sparing effect, can modify signaling molecules to decrease oxidative stress [10][11][12][13][14]24,25]. In addition, vitamin B-12 could also act as an anti-inflammation agent through the mechanisms of down regulation of the transcription factor nuclear factor-kappa B (NF-kB), inhibition of nitric oxide synthase, and promotion of oxidative phosphorylation [25][26][27]. ...
Diabetes is considered an oxidative stress and a chronic inflammatory disease. The purpose of this study was to investigate the correlations between vitamin B-12 status and oxidative stress and inflammation in diabetic vegetarians and omnivores. We enrolled 154 patients with type 2 diabetes (54 vegetarians and 100 omnivores). Levels of fasting glucose, glycohemoglobin (HbA1c), lipid profiles, oxidative stress, antioxidant enzymes activity, and inflammatory makers were measured. Diabetic vegetarians with higher levels of vitamin B-12 (>250 pmol/L) had significantly lower levels of fasting glucose, HbA1c and higher antioxidant enzyme activity (catalase) than those with lower levels of vitamin B-12 (≤250 pmol/L). A significant association was found between vitamin B-12 status and fasting glucose (r = -0.17, p = 0.03), HbA1c (r = -0.33, p = 0.02), oxidative stress (oxidized low density lipoprotein-cholesterol, r = -0.19, p = 0.03), and antioxidant enzyme activity (catalase, r = 0.28, p = 0.01) in the diabetic vegetarians; vitamin B-12 status was significantly correlated with inflammatory markers (interleukin-6, r = -0.33, p < 0.01) in diabetic omnivores. As a result, we suggest that it is necessary to monitor the levels of vitamin B-12 in patients with diabetes, particularly those adhering to a vegetarian diet.
... Although the mechanism is still unknown, it could be hypothesized that micronutrients regulate cytokine release following mast cell degranulation by their immunomodulatory properties. Wheatley reported an inverse relationship between vitamin B12 and tumour necrosis factor alpha [10], which is upregulated in CSU patients [11]. Iron-induced decreases in the number of mast cell granules and percentage of mast cell degranulation have also been observed in vitro [12]. ...
Previous reports have suggested a possible role for vitamin D in the etiology of chronic spontaneous urticaria (CSU); however, little information is available regarding the role of other micronutrients. We, therefore, analyzed vitamin D, vitamin B12, and ferritin levels in CSU patients (
n
=
282
) from a preexisting database at Southampton General Hospital. Data were compared against mean micronutrient levels of the general population of the UK, obtained from the National Diet and Nutrition Survey. Vitamin D levels of CSU patients were found to be higher than those of the general UK population (
P
=
0.001
). B12 levels were lower in patients with CSU (
P
<
0.001
) than in the general population. Ferritin levels were found to be lower in male CSU patients than in the general male population (
P
=
0.009
). This association between low B12 and iron levels and CSU might indicate a causal link, with micronutrient replacement as a potential therapeutic option.
... Vitamin B12 is also required for the isomerisation of d-leucine to leucine which is found in certain regulatory proteins like transcription factors NF-ĸB (nuclear factor kappa-light-chain-enhancer of activated B cells), Myc and Fos. Vitamin B12 may therefore have a secondary oncogene role 7 . ...
Vitamin B12 is an essential micronutrient, with significant intracellular functions. Vitamin B12 deficiency is common in the critically ill population and is associated with significant deficiency syndromes.
Increased vitamin B12 levels are associated with worse outcomes in critically ill patients and warrant systemic workup for malignancies and chronic diseases, particularly of the hepatic and hematological systems.
Normal serum levels of vitamin B12 should be aimed for in the critically ill; however, there seems to be a minimal role for therapeutic use of vitamin B12 in the absence of deficiency.
... Endogenous cobalamins and cobinamides (Cbi) may play important roles regulating NOS activity in normal and pathological conditions [329]. Regulatory function of cobalamins towards nitric oxide synthases was brought up and discussed by Weinberg et al. [329,333] and also by Wheatley et al. [334,335]. Recently, Weinberg et al. [329] reported that OH-Cbl, Cbi, and (CN) 2 Cbi can potently inhibit the enzymatic function of NOS and thus block the biological formation of NO. It is to be reminded that (as stated above) OH-Cbl can bind and scavenge NO; the same was observed for OH-Cbi; thus, these two agents are able to regulate the NOS/NO system both by decreasing NOS activity and by quenching the existing NO pool. ...
A comprehensive overview is presented of the biologically relevant coordination chemistry of nitrosyls and its biochemical consequences. Representative classes of metal nitrosyls are introduced along with the structural and bonding aspects that may have consequences for the biological functioning of these complexes. Next, the biological targets and functions of nitrogen (II) oxide are discussed. Up-to-date biochemical applications of metal nitrosyls are reviewed.
... An insufficient body burden of cobalamin in humans results in a complex spectrum of pathologies, including pernicious anemia, megaloblastic anemia, peripheral neuropathy, dementia, depression, impaired cognition, and autoimmune dysfunction (1)(2)(3)(4)(5)(6). Cobalamin deficiency is often the result of poor intestinal absorption of cobalamin, but in some cases the cofactor form of cobalamin is specific to the underlying biological pathology of the disease. ...
The current analytical high-performance liquid chromatography (HPLC) methods by which the various forms of cobalamin can be separated and quantified are limited to tedious chromatographic gradients with run times of 20-30 min and limits of detection (LOD) of 2 nM (2.7 ng/mL). This LOD is far above the physiological range of 148-443 pM (200-600 pg/mL) that is the normal total cobalamin level in human plasma. In this manuscript, benefits of ultra-performance liquid chromatography (UPLC) in which the stationary phase particle size may be reduced from 3.5 ?m with a mobile-phase backpressure of 6000 psi in traditional analytical HPLC to a stationary phase particle size of 1.7 ?m and a mobile phase backpressure of 15,000 psi in UPLC are reported. UPLC can more than double the chromatographic resolution and reduce each chromatographic run time by 10-fold, such that a complete analysis takes only 3 min per sample.
... , H 2 O 2 and homocysteineinduced oxidative stress [23][24][25]. Furthermore Cbl supplementation has been used to treat a wide range of chronic inflammatory diseases [26,27]. ...
Although now recognized to be an important reactive nitrogen species in biological systems that modifies the structures of proteins, DNA and lipids, there are few studies on the reactivity of NO2, including the reactions between NO2 and transition metal complexes. We report kinetic studies on the reactions of NO2 with two forms of vitamin B12 — cob(II)alamin and nitrocobalamin. UV–visible spectroscopy and HPLC analysis of the product solution show that NO2 cleanly oxidizes the metal center of cob(II)alamin to form nitrocobalamin, with a second-order rate constant of (3.5 ± 0.3) × 108 M− 1 s− 1 (pH 7.0 and 9.0, room temperature, I = 0.20 M). The stoichiometry of the reaction is 1:1. No reaction is detected by UV–visible spectroscopy and HPLC analysis of the product solution when nitrocobalamin is exposed to up to 2.0 mol equiv. NO2.
... It is likely that Cbl has biological roles beyond its ability to act as a cofactor for the two mammalian B 12 -dependent enzyme reactions (reviewed by Solomon [19]). Cbl supplementation can be beneficial in treating a range of inflammatory and viral-based diseases associated with oxidative stress [10][11][12][13][14][15][16] and also modulates the immune response [64,65]. Moreover, high doses of Cbl have been used to treat pernicious anemia for decades with no apparent toxicity [66]. ...
Superoxide (O(2)(•-)) is implicated in inflammatory states including arteriosclerosis and ischemia-reperfusion injury. Cobalamin (Cbl) supplementation is beneficial for treating many inflammatory diseases and also provides protection in oxidative-stress-associated pathologies. Reduced Cbl reacts with O(2)(•-) at rates approaching that of superoxide dismutase (SOD), suggesting a plausible mechanism for its anti-inflammatory properties. Elevated homocysteine (Hcy) is an independent risk factor for cardiovascular disease and endothelial dysfunction. Hcy increases O(2)(•-) levels in human aortic endothelial cells (HAEC). Here, we explore the protective effects of Cbl in HAEC exposed to various O(2)(•-) sources, including increased Hcy levels. Hcy increased O(2)(•-) levels (1.6-fold) in HAEC, concomitant with a 20% reduction in cell viability and a 1.5-fold increase in apoptotic death. Pretreatment of HAEC with physiologically relevant concentrations of cyanocobalamin (CNCbl) (10-50nM) prevented Hcy-induced increases in O(2)(•-) and cell death. CNCbl inhibited both Hcy and rotenone-induced mitochondrial O(2)(•-) production. Similarly, HAEC challenged with paraquat showed a 1.5-fold increase in O(2)(•-) levels and a 30% decrease in cell viability, both of which were prevented with CNCbl pretreatment. CNCbl also attenuated elevated O(2)(•-) levels after exposure of cells to a Cu/Zn-SOD inhibitor. Our data suggest that Cbl acts as an efficient intracellular O(2)(•-) scavenger.
... It is proposed that such TC elevations signal a need for vitamin B 12 central to the resolution of inflammation. 53 Vitamin B 12 is an effective scavenger of nitric oxide (NO). 54 Septic shock has an extremely high mortality rate, with approximately 200 000 people dying from sepsis annually in the US. ...
Unlabelled:
Vitamin B12 affects the peripheral and central nervous systems, bone marrow, skin and mucous membranes, bones, and vessels, as well as the normal development of children. Although there is undoubtedly an association between vitamin B12 and homocysteinemia, their relative influence on cardiovascular events is controversial. Some large studies confirm that a supplementation with group B vitamins did not reduce the risk of major cardiovascular events or all-cause mortality in patients with vascular disease. The outcomes of these and similar trials could have been different had the researchers considered the following points: Using vitamin B12 or B-complex as secondary prevention of cardiovascular events for patients with irreversible changes of blood vessels is probably in error. Rather, vitamin B12 or B-complex should be used as primary prevention. Also, using high doses of vitamin B12 will probably be more effective than using low doses of "group B vitamins" The effect of vitamin B12 on the proliferation of malignant cells has been examined in vivo and in vitro in numerous studies. Their results indicate that methylcobalamin inhibits the proliferation of malignant cells and propose the possibility of methylcobalamin as a candidate of potentially useful agents for the treatment for some malignant tumors. There are many articles indicating the increasing prevalence of low vitamin B12 level in different segments of general population. In order to prevent serious health problems, vitamin B12 routine fortification should be seriously considered and discussed.
Keywords:
vitamin B12; homocysteine; malignancy; vitamin B12 routine fortification; recurrent aphthous stomatitis.
Since the dawn of man, inflammation has been known to humanity, as it is marked by pain. Inflammation processes are related to serious chronic diseases with irreversible damage to the organism, being crucial for the development of anti-inflammatory agents. Among the existing anti-inflammatory drugs, non-steroidal and glucocorticoids are commonly used; however, these compounds have been described as responsible for the increased risk of upper gastrointestinal complications and many other side effects. Therefore, it is not shocking that ethnobotany leads most modern studies on the discovery of anti-inflammatory agents obtained from natural matrices. Extracts from plants and isolated substances have demonstrated anti-inflammatory effects in a set of in vitro and in vivo anti-inflammatory models. This review describes inflammation processes with an emphasis on the most common related diseases, while also describing the most promising natural anti-inflammatory agents, by reporting on their obtention processes, mechanisms of action, and applications.
The literature review discusses the role of vitamins (in particular, B vitamins) in maintaining neuroprotective and antioxidant properties of the retina in glaucomatous optic neuropathy, and presents the data from foreign research papers devoted to studying the positive influence of vitamins of this group on the condition of ganglion cells of the retina and axons of the optic nerve.
Corona Virus/ Covid-19/ SARS-Cov-2 has ground the world to a halt and is showing up the deficiencies of our health care systems everywhere, and the vulnerability of the global population. When Covid-19 kills, it kills through Acute Respiratory Distress Syndrome/ ARDS which, in effect, kills by a sepsis related process. Thus ARDS is fuelled by the proverbial "cytokine storm" of sepsis. It has also been reported that people who die of Covid 19 ARDS have a depletion of Natural Killer/NK cells,, and that severe cases of Covid-19 have significantly lower T lymphocyte counts with depressed immune function in general [Chen,
This study was carried out to investigate the potential effects of vitamin B12 and sitagliptin, and their possible synergistic effect with doxorubicin (DOX) on the Ehrlich solid tumor model. B12, sitagliptin, and their combination with DOX were administered to tumor‐bearing mice for 21 days. Treatment with B12, sitagliptin, as well as their combinations with DOX caused a significant inhibition of tumor growth and increased the survival time. Malondialdehyde levels and the relative expression of tumor necrosis factor‐α and nuclear factor kappa B were significantly decreased, whereas the total antioxidant capacity was significantly increased in all treated groups, except the DOX‐treated one, when compared with the positive control group. Moreover, increased apoptosis was also observed by increased cleaved caspase‐3 immunostaining and histopathological examination. In conclusion, the antitumor activity of B12 and sitagliptin could be attributed to their ability to induce apoptosis and suppress oxidative stress and inflammation.
Critical illness commonly presents as a systemic inflammatory process. Through this inflammation, there is an enhanced production of reactive oxygen and nitrogen species combined with marked reductions in protective plasma antioxidant concentrations. This imbalance is referred to as oxidative stress and is commonly encountered in numerous disease states in the critically ill including sepsis, trauma, acute respiratory distress syndrome, and burns. Oxidative stress can lead to cellular, tissue and organ damage as well as increased morbidity and mortality in critically ill patients. Supplementation with exogenous micronutrients to restore balance and antioxidant concentrations in critically ill patients has been considered for several decades. It is proposed that antioxidant vitamins, such as vitamins A and C, may minimize oxidative stress and improve clinical outcomes. Vitamin B formulations may play a role in curtailing lactic acidosis and are recently being evaluated as an acute phase reactant. However, few large, randomized trials specifically investigating the role of vitamin supplementation in the critically ill patient population are available. This article seeks to review recently published literature surrounding the role of supplementation of vitamins A, B and C in critically ill patients.
Background:
Knowledge graphs can represent the contents of biomedical literature and databases as subject-predicate-object triples, thereby enabling comprehensive analyses that identify e.g. relationships between diseases. Some diseases are often diagnosed in patients in specific temporal sequences, which are referred to as disease trajectories. Here, we determine whether a sequence of two diseases forms a trajectory by leveraging the predicate information from paths between (disease) proteins in a knowledge graph. Furthermore, we determine the added value of directional information of predicates for this task. To do so, we create four feature sets, based on two methods for representing indirect paths, and both with and without directional information of predicates (i.e., which protein is considered subject and which object). The added value of the directional information of predicates is quantified by comparing the classification performance of the feature sets that include or exclude it.
Results:
Our method achieved a maximum area under the ROC curve of 89.8% and 74.5% when evaluated with two different reference sets. Use of directional information of predicates significantly improved performance by 6.5 and 2.0 percentage points respectively.
Conclusions:
Our work demonstrates that predicates between proteins can be used to identify disease trajectories. Using the directional information of predicates significantly improved performance over not using this information.
Persistent physical impairment is frequently encountered after critical illness. Recent data point towards mitochondrial dysfunction as an important determinant of this phenomenon. This narrative review provides a comprehensive overview of the present knowledge of mitochondrial function during and after critical illness and the role and potential therapeutic applications of specific micronutrients to restore mitochondrial function. Increased lactate levels and decreased mitochondrial ATP-production are common findings during critical illness and considered to be associated with decreased activity of muscle mitochondrial complexes in the electron transfer system. Adequate nutrient levels are essential for mitochondrial function as several specific micronutrients play crucial roles in energy metabolism and ATP-production. We have addressed the role of B vitamins, ascorbic acid, α-tocopherol, selenium, zinc, coenzyme Q10, caffeine, melatonin, carnitine, nitrate, lipoic acid and taurine in mitochondrial function. B vitamins and lipoic acid are essential in the tricarboxylic acid cycle, while selenium, α-tocopherol, Coenzyme Q10, caffeine, and melatonin are suggested to boost the electron transfer system function. Carnitine is essential for fatty acid beta-oxidation. Selenium is involved in mitochondrial biogenesis. Notwithstanding the documented importance of several nutritional components for optimal mitochondrial function, at present, there are no studies providing directions for optimal requirements during or after critical illness although deficiencies of these specific micronutrients involved in mitochondrial metabolism are common. Considering the interplay between these specific micronutrients, future research should pay more attention to their combined supply to provide guidance for use in clinical practise.
Revision number:
YCLNU-D-17-01092R2.
Vitamin B12 plays a functional role in a variety of organs and body systems. The list of conditions that are affected by vitamin B12 deficiency either directly or indirectly is growing. • In some countries two factors can contribute to vitamin B12 deficiency, namely, changes in dietary pattern among segments of the population within the higher socioeconomic strata and the existence of poverty which leads to a low consumption of animal products (particularly red meat). • There is an increasing prevalence of low vitamin B12 level in different segments of the general population. • Vitamin B12 deficiency has various and serious health effects. • The early detection of vitamin B12 deficiency is essential in order to prescribe opportune treatments. • In order to prevent serious health problems, routine fortification with vitamin B12 should be seriously considered. © Springer Science+Business Media New York 2013. All rights are reserved.
The foundation of multi cellular life - therewith also of human kind - is the generation of energy in the mitochondria. With help of the citrate cyclus and the oxidative phosphorilation, 38 adenosine-triphosphate (ATP) molecules are generated from 1 glucose molecule, whereas primitive monocellular organisms can only generate 2 ATP molecules out of 1 glucose molecule through fermentation. The mitochondrial energy metabolism is of central importance for the cell; concurrently being susceptible to oxidative- (ROS) and nitrosative- (RNS) reactive compounds, so called ROS and / or RNS stress. The dysfunction of the mitochondrial metabolism is the main basis: a) for the emergence of chronic diseases (including high blood pressure, heart attack, apoplexia, type2 diabetes, cancer) and b) for organic aging. Four factors, 2 hormones vitamine D3 and melatonin -, a classic vitamine - vitamine B12 -, and an essential amino acid - glutamine - in interacting, play a decisive role in keeping the mitochondria healthy. At the same time they are of essential pre-emptive importance in avoiding chronic diseases and maintaining youthful buoyancy. If the deficits of these key substances in the metabolism are brought to balance, in combination with a hypoxie-hyperoxie-intervall-training® and/or a topical substitution of mitrope substances, the energy metabolism within the whole organism (or topically) can be regenerated and thus be rejuvenated.
The safety of Non-steroidal anti-inflammatory drugs (NSAIDs) use in clinical practice has been questioned. Clinical studies indicate that these drugs cause adverse cardiovascular effects. The aim of this study was to investigate the protective role of vitamin B complex against the cardiotoxic potency of diclofenac sodium induced cardiac damage.
Diclofenac sodium was administered intraperitoneally to rats at either 1.5 mg or 3 mg/kg body weight for 14 consecutive days. Vitamin B complex (1.6 mg B1, 1.6 mg B6 and 16.7 µg B12/kg body weight, i.p.) was co-administered daily for 3 weeks along with diclofenac administration to rats intoxicated by either of the two doses.
The results revealed that co-administration of vitamin B complex with diclofenac to rats intoxicated by either of the two doses, markedly ameliorated increases in serum markers of cardiac damage, including, (AST), creatine kinase-MB (CK-MB) as well as decreases in phosphoglucoisomerase (PGI) and lactate dehydrogenase (LDH) activities in cardiac tissue compared with intoxicated rats. The B complex also could markedly attenuate the decreases in cardiac antioxidant enzymes namely, glutathione reductase (GR), glucose-6-phosphate dehydrogenase (G-6-PDH) and catalase (CAT) compared with diclofenac intoxicated rats. Beside, the vitamin B complex successfully modulated the increases in serum glucose, serum lipid profiles, triglycerides (TGs), total cholesterol (TCh) and low density lipoprotein (LDL-C) as well as the decrease in the high density lipoprotein (HDL-C) in response to diclofenac toxicity.
These results support the use of vitamin B complex along with diclofenac therapy as a protective agent against cardiac tissue damage induced by diclofenac toxicity.
The essential but also toxic gaseous signaling molecule nitric oxide is scavenged by the reduced vitamin B12 complex cob(II)alamin. The resulting complex, nitroxylcobalamin (NO(-)-Cbl(III)), is rapidly oxidized to nitrocobalamin (NO2Cbl) in the presence of oxygen; however it is unlikely that nitrocobalamin is itself stable in biological systems. Kinetic studies on the reaction between NO2Cbl and the important intracellular antioxidant, glutathione (GSH), are reported. In this study, a reaction pathway is proposed in which the β-axial ligand of NO2Cbl is first substituted by water to give aquacobalamin (H2OCbl(+)), which then reacts further with GSH to form glutathionylcobalamin (GSCbl). Independent measurements of the four associated rate constants k1, k-1, k2, and k-2 support the proposed mechanism. These findings provide insight into the fundamental mechanism of ligand substitution reactions of cob(III)alamins with inorganic ligands at the β-axial site.
The use of empirical force field methods for modeling important systems in bioinorganic chemistry, including the cobalt corrins (derivatives of vitamin B12) and the iron porphyrins, is described. Particular attention is given to the use of molecular dynamics and simulated annealing calculations in exploring the solution structures of corrin, and those of likely complexes between the ferriprotoporphyrin-IX and the arylmethanol antimalarials.
A comprehensive overview is presented of the biologically relevant coordination chemistry of nitrosyls and its biochemical consequences. Representative classes of metal nitrosyls are introduced along with the structural and bonding aspects that may have consequences for the biological functioning of these complexes. Next, the biological targets and functions of nitrogen (II) oxide are discussed. Up-to-date biochemical applications of metal nitrosyls are reviewed.
Background. NOS/ NO inhibitors are potential therapeutics for sepsis, yet they increase clinical mortality. However, there has been no in vivo investigation of the (in vitro) NO scavenger, cobalamin's (Cbl) endogenous eects on NOS/ NO/inammatory mediators during the immune response to sepsis. Methods. We used quantitative polymerase chain reaction (qPCR), ELISA, Western blot, and NOS Griess assays, in a CBL/ mouse, acute endotoxaemia model. Results. During the immune response, pro-inammatory phase, parenteral hydroxocobalamin (HOCbl) treatment partially inhibits hepatic, but not lung, iNOS mRNA and promotes lung eNOS mRNA, but attenuates the LPS hepatic rise in eNOS mRNA, whilst paradoxically promoting high iNOS/eNOS protein translation, but relatively moderate NO production. HOCbl/NOS/ NO regulation is reciprocally associated with lower h expression of TNF-, IL-, COX-, and lower circulating TNF-, but not IL-. In resolution, h aer LPS, HOCbl completely abrogates a major late mediator of sepsis mortality, high mobility group box (HMGB) mRNA, inhibits iNOS mRNA, and attenuates LPS-induced hepatic inhibition of eNOS mRNA, whilst showing increased, but still moderate, NOS activity, relative to LPS only. experiments (LPS+D-Galactosamine) HOCbl aorded signicant, dose-dependent protection in mice Conclusions. HOCbl produces a complex, time-and organ-dependent, selective regulation of NOS/ NO during endotoxaemia, corollary regulation of downstream inammatory mediators, and increased survival. is merits clinical evaluation.
Background. NOS/ NO inhibitors are potential therapeutics for sepsis, yet they increase clinical mortality. However, there has been no in vivo investigation of the (in vitro) NO scavenger, cobalamin's (Cbl) endogenous eects on NOS/ NO/inammatory mediators during the immune response to sepsis. Methods. We used quantitative polymerase chain reaction (qPCR), ELISA, Western blot, and NOS Griess assays, in a CBL/ mouse, acute endotoxaemia model. Results. During the immune response, pro-inammatory phase, parenteral hydroxocobalamin (HOCbl) treatment partially inhibits hepatic, but not lung, iNOS mRNA and promotes lung eNOS mRNA, but attenuates the LPS hepatic rise in eNOS mRNA, whilst paradoxically promoting high iNOS/eNOS protein translation, but relatively moderate NO production. HOCbl/NOS/ NO regulation is reciprocally associated with lower h expression of TNF-, IL-, COX-, and lower circulating TNF-, but not IL-. In resolution, h aer LPS, HOCbl completely abrogates a major late mediator of sepsis mortality, high mobility group box (HMGB) mRNA, inhibits iNOS mRNA, and attenuates LPS-induced hepatic inhibition of eNOS mRNA, whilst showing increased, but still moderate, NOS activity, relative to LPS only. experiments (LPS+D-Galactosamine) HOCbl aorded signicant, dose-dependent protection in mice Conclusions. HOCbl produces a complex, time-and organ-dependent, selective regulation of NOS/ NO during endotoxaemia, corollary regulation of downstream inammatory mediators, and increased survival. is merits clinical evaluation.
O2 (.) (-) scavenger: The rate constant for the rapid reaction of the ROS superoxide with the reduced vitamin B12 radical complex cob(II)alamin was directly determined to be 3.8×10(8) M(-1) s(-1) . This rate was independent of pH over the range 5.5-8.7. These results have implications for studying the use of B12 supplements to combat diseases associated with oxidative stress.
Mammalian nitric oxide synthases (NOS) are a source of the universal second messenger, and pivotal biochemical molecule, nitric oxide (. NO). NOS are assumed to function catalytically in a haem-centred manner, by analogy with cytochrome P450. Yet, they differ significantly. Cobalamin, vitamin B12, is believed to function almost solely as an . NO scavenger and, latterly, as a direct, physiological inhibitor of the NOS. Yet, in pathology, associated to cobalamin deficiency, functional or otherwise, NOS over-produce superoxide, peroxynitrite (ONOO -), and other reactive nitrite species, rather than . NO (Figure 7). This paper offers a radical, new solution to the gaps and inconsistencies in the current understanding of the mechanism of haem-centred NOS catalysis, which also challenges the other existing paradigm of cobalamin as just an . NO mop. Examination of a wide diversity of NOS and cobalamin-dependent enzyme structure-function studies, as well as data from the . NO/cobalamin chemical, biochemical, immunological, genetic, and clinical literature, offers indications that cobalamin, specifically, in one of its active forms, adenosylcobalamin (AdoCbl), may have a third, eukaryotic coenzyme function as the principal cofactor of well-regulated NOS catalysis in vivo. The AdoCbl-centred NOS reaction is described in detail (Figure 5), and some existing evidence that, in vitro, without AdoCbl, NOS turnover activity is significantly slower than in in vivo AdoCbl-rich environments, is presented. AdoCbl, in conjunction with tetrahydrobiopterin, couples NOS oxygen binding/activation to L-arginine hydroxylation and . NO synthesis much more effectively than does haem, overcoming NOS spatial and redox problems, leading to productive catalysis, decreased radical formation/escape, with a consequent increased ratio of . NO to ONOO -, and prevention of pathology (Figures 5 & 7). In vivo, haem-centred NOS catalysis may, in fact, be the back-up NOS reaction, and it"s predominance in the absence of AdoCbl, with a consequent lowering of the . NO/ONOO-ratio, is the real source of supposedly . NO derived pathology.
To expand the understanding of potential pathways through which food insecurity is associated with adverse health outcomes, we investigated whether food insecurity is associated with nutritional levels, inflammatory response, and altered immune function.
We performed a cross-sectional analysis of the National Health and Nutrition Examination Survey (1999-2006) with 12,191 participants. We assessed food insecurity using the US Department of Agriculture food security scale module and measured clinical biomarkers from blood samples obtained during participants' visits to mobile examination centers.
Of the study population, 21.5% was food insecure. Food insecurity was associated with higher levels of C-reactive protein (adjusted odds ratio [AOR]=1.21; 95% confidence interval [CI]=1.04, 1.40) and of white blood cell count (AOR=1.36; 95% CI=1.11, 1.67). White blood cell count partly mediated the association between food insecurity and C-reactive protein.
These findings show that food insecurity is associated with increased inflammation, a correlate of chronic diseases. Immune response also appears to be a potential mediator in this pathway.
The X-ray structures of three new crystals of nitroxylcobalamin (NOCbl) have been determined. Unlike our earlier reported structure in which NOCbl was partially oxidized (L. Hannibal, C. A. Smith, D. W. Jacobsen and N. E. Brasch, Angew. Chem., Int. Ed. 2007, 46, 5140), the O atom of the nitroxyl ligand is located in a single position with a N=O bond distance of 1.12-1.14 Å, consistent with a double bond. The Co-N-O angle is in the 118.9-120.3 Å range. The α-axial Co-N(dimethylbenzimidazole) (Co-NB3) bond distance is a remarkable 2.32-2.35 Å in length, ~0.1 Å longer than that reported for all other cobalamin structures. The change in the Gibbs free energy for the base-on/base-off equilibrium now correlates extremely well with the Co-NB3 bond distance, as observed for other cobalamins.
To analyse the anti-inflammatory and antioxidant properties of vitamin B12 and evaluate current evidence on vitamin B12 status in the critically ill with systemic inflammation.
Data on vitamin B12 status of intensive care unit patients are scarce. Cobalamins could potentially be useful agents for inhibiting nitric oxide synthase and nitric oxide production, controlling nuclear factor-kappa B activation, and restoring optimal bacteriostasis and phagocytosis in which transcobalamins play a proven role. The antioxidant properties of vitamin B12, with a glutathione-sparing effect, are secondary to stimulation of methionine synthase activity and reaction with free oxygen or nitrogen radicals. Large parenteral doses are routinely administered for cyanide poisoning, with only mild, reversible side-effects. Current evidence suggests that high-dose parenteral vitamin B12 may prove an innovative approach to treat critically ill systemic inflammatory response syndrome patients, especially those with severe sepsis/septic shock. In this setting, vitamin B12 and transcobalamins could modulate systemic inflammation contributing to the anti-inflammatory cascade and potentially improve outcome.
Despite evidence from animal studies, so far there are no clinical intervention trials that have studied vitamin B12 as a pharmaconutrient strategy for critical care. Well designed animal and clinical studies are required to clarify several outstanding questions on the optimal posology, safety, and efficacy of high-dose vitamin B12 in the critically ill.
Endotoxin, a constituent of Gram-negative bacteria, stimulates macrophages to release large quantities of tumor necrosis factor
(TNF) and interleukin-1 (IL-1), which can precipitate tissue injury and lethal shock (endotoxemia). Antagonists of TNF and
IL-1 have shown limited efficacy in clinical trials, possibly because these cytokines are early mediators in pathogenesis.
Here a potential late mediator of lethality is identified and characterized in a mouse model. High mobility group–1 (HMG-1)
protein was found to be released by cultured macrophages more than 8 hours after stimulation with endotoxin, TNF, or IL-1.
Mice showed increased serum levels of HMG-1 from 8 to 32 hours after endotoxin exposure. Delayed administration of antibodies
to HMG-1 attenuated endotoxin lethality in mice, and administration of HMG-1 itself was lethal. Septic patients who succumbed
to infection had increased serum HMG-1 levels, suggesting that this protein warrants investigation as a therapeutic target.
Aspirin therapy inhibits prostaglandin biosynthesis without directly acting on lipoxygenases, yet via acetylation of cyclooxygenase 2 (COX-2) it leads to bioactive lipoxins (LXs) epimeric at car- bon 15 (15-epi-LX, also termed aspirin-triggered LX (ATL)). Here, we report that inflamma- tory exudates from mice treated with v -3 polyunsaturated fatty acid and aspirin (ASA) generate a novel array of bioactive lipid signals. Human endothelial cells with upregulated COX-2 treated with ASA converted C20:5 v -3 to 18 R -hydroxyeicosapentaenoic acid (HEPE) and 15 R -HEPE. Each was used by polymorphonuclear leukocytes to generate separate classes of novel trihydroxy-containing mediators, including 5-series 15 R -LX 5 and 5,12,18 R -triHEPE. These new compounds proved to be potent inhibitors of human polymorphonuclear leukocyte transendothelial migration and infiltration in vivo (ATL analogue . 5,12,18 R -triHEPE . 18 R - HEPE). Acetaminophen and indomethacin also permitted 18 R -HEPE and 15 R -HEPE genera- tion with recombinant COX-2 as well as v -5 and v -9 oxygenations of other fatty acids that act on hematologic cells. These findings establish new transcellular routes for producing arrays of bioactive lipid mediators via COX-2-nonsteroidal antiinflammatory drug-dependent oxygen- ations and cell-cell interactions that impact microinflammation. The generation of these and re- lated compounds provides a novel mechanism(s) for the therapeutic benefits of v -3 dietary sup- plementation, which may be important in inflammation, neoplasia, and vascular diseases.
Hydrogen peroxide and oxygen radicals are agents commonly produced during inflammatory processes. In this study, we show that micromolar concentrations of H2O2 can induce the expression and replication of HIV-1 in a human T cell line. The effect is mediated by the NF-kappa B transcription factor which is potently and rapidly activated by an H2O2 treatment of cells from its inactive cytoplasmic form. N-acetyl-L-cysteine (NAC), a well characterized antioxidant which counteracts the effects of reactive oxygen intermediates (ROI) in living cells, prevented the activation of NF-kappa B by H2O2. NAC and other thiol compounds also blocked the activation of NF-kappa B by cycloheximide, double-stranded RNA, calcium ionophore, TNF-alpha, active phorbol ester, interleukin-1, lipopolysaccharide and lectin. This suggests that diverse agents thought to activate NF-kappa B by distinct intracellular pathways might all act through a common mechanism involving the synthesis of ROI. ROI appear to serve as messengers mediating directly or indirectly the release of the inhibitory subunit I kappa B from NF-kappa B.
To evaluate the possible role of glutathionylcobalamin (GS-Cbl) in the intracellular metabolism of cobalamin, the following reactions were analyzed using extracts of rabbit spleen: (i) decyanation of cyanocobalamin; (ii) utilization of GS-Cbl by cobalamin reductase; (iii) participation of GS-Cbl in methionine biosynthesis; and (iv) conversion of GS-Cbl to adenosylcobalamin. Decyanation of cyanocobalamin required reduced glutathione which appeared to form a complex with the cobalamin. This complex decomposed during the extraction steps to sulfitocobalamin which was identified by high-performance liquid chromatography. Cobalamin reductase in spleen extract was more active with GS-Cbl than with aquocobalamin or cyanocobalamin as substrates (specific activities: 10.4, 2.8 and 0.93 nmol/mg/min, respectively). Methionine synthase utilized GS-Cbl as cofactor more efficiently than aquocobalamin or cyanocobalamin based on initial rates of enzyme activity. This suggests that GS-Cbl is a more direct precursor of the coenzyme required for methionine synthase. Formation of adenosylcobalaminm from GS-Cb1 was four times greater than from aquocobalamin alone. Based on these results, we propose that GS-Cbl or a closely related thiol-cobalamin adduct is a proximal precursor in cobalamin coenzyme biosynthesis.
Nitric oxide (NO) is a paramagnetic gas that has been implicated in a wide range of biologic functions. The common pathway to evoke the functional response frequently involves the formation of an iron- nitrosyl complex in a target (heme) protein. In this study, we report on the interactions between NO and cobalt-containing vitamin B12 derivatives. Absorption spectroscopy showed that of the four Co(III) derivatives (cyanocobalamin [CN-Cbl], aquocobalamin [H2O-Cbl], adenosylcobalamin [Ado-Cbl], and methylcobalamin [MeCbl]), only the H2O- Cbl combined with NO. In addition, electron paramagnetic resonance spectroscopy of H2O-Cbl preparations showed the presence of a small amount of Cob-(II)alamin that was capable of combining with NO. The Co(III)-NO complex was very stable, but could transfer its NO moiety to hemoglobin (Hb). The transfer was accompanied by a reduction of the Co(III) to Co(II), indicating that NO+ (nitrosonium) was the leaving group. In accordance with this, the NO did not combine with the Hb Fe(II)-heme, but most likely with the Hb cysteine-thiolate. Similarly, the Co(III)-NO complex was capable of transferring its NO to glutathione. Ado-Cbl and Me-Cbl were susceptible to photolysis, but CN- Cbl and H2O-Cbl were not. The homolytic cleavage of the Co(III)-Ado or Co(III)-Me bond resulted in the reduction of the metal. When photolysis was performed in the presence of NO, formation of NO-Co(II) was observed. Co(II)-nitrosyl oxidized slowly to form Co(III)-nitrosyl. The capability of aquocobalamin to combine with NO had functional consequences. We found that nitrosylcobalamin had diminished ability to serve as a cofactor for the enzyme methionine synthase, and that aquocobalamin could quench NO-mediated inhibition of cell proliferation. Our in vitro studies therefore suggest that interactions between NO and cobalamins may have important consequences in vivo.
The neutrophil response to inflammatory stimuli involves the formation of reactive oxygen species and secretion of granule enzymes. In studying secretion of vitamin B12 binding protein by human neutrophils, we noted a major decrease in total recoverable activity from the extracellular fluid plus the stimulated cells (54% of resting cells). Recovery of B12 binding protein from neutrophils exposed to phorbol myristate acetate or opsonized zymosan was significantly enhanced on addition of heme enzyme inhibitors (azide, cyanide) or catalase or when halide-free medium was used. The changes in B12 binding protein recovery were attributable entirely to increases in extracellular fluid levels, and cell pellet content was unaffected. These data indicate extracellular destruction of functional B12 binding protein by the halide-dependent heme enzyme myeloperoxidase and H2O2. Kinetic studies demonstrated rapid secretion of B12 binding protein in the first two to five minutes, followed by its inactivation over the next 20 to 30 minutes. A cell-free extract of vitamin B12 binding protein was readily inactivated on exposure to purified myeloperoxidase, H2O2, and a halide. These findings document a functional interaction among products of the neutrophil specific granules (B12 binding protein), azurophil granules (myeloperoxidase), and metabolic burst (H2O2). They provide an interesting model for the modulation of the inflammatory response by oxidation of secretory products of neutrophils.
Incorporation of vitamin B12 into L1210 cells requires the protein binder transcobalamin II (TCII). The process is saturable, follows Michaelis-Menten kinetics (Km = 2.5 X 10(-9) M at 37 degrees C), is both temperature and calcium (K50 - 1 X 10(-6) M) dependent, and is inhibited by apo-TCII, indicating the presence of a TCII specific receptor on the cell membrane. B12 also leaves the cell by a calcium- independent pathway bound to either TCII or to a protein with chromatographic properties similar to those of TCIII. Since intact TCII- B12 can be found in the cytosol and can promote B12 uptake by mitochondria, it is proposed that the B12 released from the cell bound to the TCIII-like protein is derived by mitochondrial processing of incorporated TCII-B12. The slower time course of release of the latter B12 is consistent with this postulate.
Abnormalities in some transcobalamin unsaturated binding capacities (TCUBBC) were found in some patients with treated pernicious anemia who had elevated TC II-UBBC, R-UBBC, and total UBBC, in gastrectomized patients with latent vitamin B12 deficiency who had elevated R-UBBC and UBBC, and in patients with obstructive jaundice who had elevated TC IIUBBC and UBBC. No abnormalities were found in patients who had untreated pernicious anemia, folate deficiency, unclassifiable megaloblastic anemia, tobacco amblyopia, or low serum B12 level but normal capacity to absorb vitamin B12.
cGMP-dependent protein kinase (PKG) expression is highly variable and decreases in cultured vascular smooth muscle cells (VSMCs), exposure of cells to nitric oxide (NO), or in response to balloon catheter injury in vivo. In this study, the mechanisms of human type I PKG-α (PKG-Iα) gene expression were examined. Three structurally unrelated NO donors decreased PKG-Iα promoter activity after transfection of a promoter/luciferase construct in VSMCs. Promoter deletion analysis demonstrated that (1) a 120-bp promoter containing tandem Sp1 sites was sufficient to drive basal PKG-Iα promoter activity, and (2) NO was inhibitory at this site. Cyclic nucleotide analogues also suppressed PKG-Iα promoter activity with cAMP being more potent than cGMP. The effects of cyclic nucleotides to suppress PKG-Iα promoter activity were attenuated by a specific cAMP-dependent protein kinase (PKA) inhibitor. Single or double mutation of Sp1 binding sites abolished PKG-Iα expression. Moreover, Sp1 binding activity on the PKG-Iα promoter was detected in A7r5 cells, and this binding was inhibited by NO and cyclic nucleotides. These results indicate that PKG-Iα gene expression is driven by an Sp1 transcription mechanism, and that NO and cAMP inhibit Sp1-mediated PKG-Iα gene expression through separate mechanisms.
Researchers are finding ways to help nerves regenerate, and hope for therapies is growing
Objective:
To explore the associations of low serum levels of vitamin B(12) and folate with AD occurrence.
Methods:
A population-based longitudinal study in Sweden, the Kungsholmen
Project:
A random sample of 370 nondemented persons, aged 75 years and older and not treated with B(12) and folate, was followed for 3 years to detect incident AD cases. Two cut-off points were used to define low levels of vitamin B(12) (< or =150 and < or =250 pmol/L) and folate (< or =10 and < or =12 nmol/L), and all analyses were performed using both definitions. AD and other types of dementia were diagnosed by specialists according to DSM-III-R criteria.
Results:
When using B(12) < or =150 pmol/L and folate < or =10 nmol/L to define low levels, compared with people with normal levels of both vitamins, subjects with low levels of B(12) or folate had twice higher risks of developing AD (relative risk [RR] = 2.1, 95% CI = 1.2 to 3.5). These associations were even stronger in subjects with good baseline cognition (RR = 3.1, 95% CI = 1.1 to 8.4). Similar relative risks of AD were found in subjects with low levels of B(12) or folate and among those with both vitamins at low levels. A comparable pattern was detected when low vitamin levels were defined as B(12) < or =250 pmol/L and folate < or =12 nmol/L.
Conclusions:
This study suggests that vitamin B(12) and folate may be involved in the development of AD. A clear association was detected only when both vitamins were taken into account, especially among the cognitively intact subjects. No interaction was found between the two vitamins. Monitoring serum B(12) and folate concentration in the elderly may be relevant for prevention of AD.
• Serum cobalamin (vitamin B12) levels were analyzed retrospectively in 17 patients with primary degenerative dementia and 11 with specific demonstrable causes of dementia (secondary dementia). The prevalence of low cobalamin levels was significantly increased in primary dementia (29% vs 0% in secondary dementia). Because typical findings of deficiency often seemed absent, we prospectively studied two other patients with primary dementia and low cobalamin levels. Neither of these two had megaloblastic anemia; one had a normal Schilling test while the other's was borderline. Despite this absence of the expected findings, the deoxyuridine suppression test gave biochemical evidence of cobalamin deficiency in both cases. Our survey of 28 patients thus established that low serum cobalamin levels are frequent in primary dementia. Our findings in the two prospectively studied cases (as well as in some of the patients in the survey) indicate that these levels are associated in at least some cases with an atypical deficiency state rather than with disorders such as pernicious anemia. Such atypical deficiency states cannot be identified by classic hematological criteria or by the Schilling test.
(Arch Intern Med 1987;147:429-431)
Nitric oxide (·NO) released byS-nitrosoglutathione (GSNO) inhibited enzymatic activities of rat heart mitochondrial membranes. Cytochrome oxidase activity was inhibited to one-half at an effective ·NO concentration of 0.1 μM, while succinate– and NADH–cytochrome-creductase activities were half-maximally inhibited at 0.3 μM·NO. Submitochondrial particles treated with ·NO (either from GSNO or from a pure solution) showed increased[formula]and H2O2production when supplemented with succinate alone, at rates that were comparable to those of control particles with added succinate and antimycin. Rat heart mitochondria treated with ·NO also showed increased H2O2production. Cytochrome spectra and decreased enzymatic activities in the presence of ·NO are consistent with a multiple inhibition of mitochondrial electron transfer at cytochrome oxidase and at the ubiquinone–cytochromebregion of the respiratory chain, the latter leading to the increased[formula]production. Electrochemical detection showed that the buildup of a ·NO concentration from GSNO was interrupted by submitochondrial particles supplemented with succinate and antimycin and was restored by addition of superoxide dismutase. The inhibitory effect of ·NO on cytochrome oxidase was also prevented under the same conditions. Apparently, mitochondrial[formula]reacts with ·NO to form peroxynitrite and, by removing ·NO, reactivates the previously inhibited cytochrome oxidase. It is suggested that, at physiological concentrations of ·NO, inhibition of electron transfer, ·NO-induced[formula]production, and ONOO⁻formation participate in the regulatory control of mitochondrial oxygen uptake.
Almost exactly ten years following the first publication on NF-κB (Sen and Baltimore 1986), researchers working on transcriptional regulation by NF-κB/Rel and IκB proteins gathered for the third time to discuss recent developments in the field (Madrid, July 8-10, 1996). The first meeting of its kind was a Howard Hughes workshop at the NIH in November 1992 and the second one a Banbury Conference held at Cold Spring Harbor in October 1993. This year's meeting was organized by R. Bravo (Bristol-Myers Squibb, Princeton) and P. S. Lazo (Universidad de Oviedo) and held at the Juan March Foundation in Madrid, Spain.
A fifteen-year-old girl, with a clean medical history, was admitted to the intensive care unit 90 minutes after ingestion of 2.5 g potassium cyanide. She had typical signs of severe cyanide poisoning including deep coma, circulatory failure, and major metabolic acidosis. Gastric lavage and antidotal treatment with 4 g hydroxocobalamin and 8 g sodium hyposulfite was administered without delay together with supportive treatment consisting of mechanical ventilation with Fio2, blood alkalinisation and administration of β-stimulants. These measures led to a rapid clinical improvement. The ventilatory support was discontinued after 24 hours and the patient left the intensive care unit on the fourth day with only slightly impaired mental status. She survived despite a very high blood cyanide concentration (494 μmol · l−1 on admission) probably because of the rapid symptomatic and antidotal treatment.
In the present state of knowledge, it appears that the sole biochemical effect of nitrous oxide is to block the transmethylation reaction. However, the metabolic consequences are not trivial. There are two products of the reaction, methionine and tetrahydrofolate. Metabolic consequences may be attributable to depletion of either or both products. However, their relative importance is not yet clarified, particularly in the clinical situation where other biochemical abnormalities may be present.
Following an introduction into solvent radical-cage effects and the general use of cage-trapping methods to study solvent-cage effects, the bio-organometallic enzyme cofactor coenzyme B-12 (adocobalamin; AdoCbl) is studied using the TEMPO (2,2,6,6-tetramethylpiperidinyl-1-oxy) nitroxide cage-trapping method. Specifically, the products, kinetics, and mechanism of AdoCbl Co-C thermolysis in ethylene glycol are presented at high [TEMPO], results which establish (after ruling out other conceivable mechanisms and interpretations) a radical-cage effect for AdoCbl in ethylene glycol. The results also allow a limit to be placed on the important fractional cage efficiency factor (F(c)) for AdoCbl, 0.4 less-than-or-equal-to F(c) less-than-or-equal-to 1.0 (where F(c) is defined as the ratio of cage recombination to the sum of all competing cage processes, F(c) = k-1/SIGMAk(cage)). The findings suggest possibly important and more general, but little recognized, biological analogs of cage effects in coenzyme B-12-dependent enzymes. Also discussed is the quite speculative but novel and especially intriguing idea that B-12-dependent enzymes may include protein ''ultimate radical cage'' and ''ultimate radical trap'' effects.
Cell proliferation is regulated by multiple signaling pathways and stress surveillance systems to ensure cell division takes place with fidelity. In response to oxidative stress, cells arrest in the cell-cycle and aberrant redox control of proliferation underlies the pathogenesis of many diseases including cancer and neurodegenerative disorders. Redox sensing of cell-cycle regulation has recently been shown to involve reactive cysteine thiols that function as redox sensors in cell-cycle regulators. By modulating cell-cycle regulators these redox-active thiols ensure cell division is executed at the right redox environment. This review summarizes recent findings on regulation of cell division by the oxidation of cysteines in cell division regulators and the potential of targeting these critical cysteine residues for cancer therapy.
IntroductionThe Intrinsic Factor-Vitamin B12 ReceptorReceptors for Transcobalamin-Vitamin B12The Receptor Mediating Uptake of Haptocorrin-B12Conclusions and Future Perspectives
A study of the three serum transcobalamins (TC) in myeloproliferative disorders and acute leukaemia has suggested a granulocyte origin for the three binders; the later stages of this cell line might be releasing ‘TC I’and ‘TC III’while ‘TC II’which is increased in sera from patients with acute myelogenous leukaemia, probably originates at least in part from myeloblasts.
The intracellular content of each TC has been studied in normal and leukaemic bone marrow cells after separation on a discontinuous bovine serum albumin gradient. Myeloblasts contain a TC II-like protein almost exclusively but promyelocytes contain a TC I-like protein which increases as the cells mature whilst ‘TC II’decreases. A TC III-like binder parallels ‘TC I’but appears later and reaches a maximum in the polymorphonuclear cells. In various types of leukaemia, abnormal TC distributions are related either to marrow replacement by the blast cells or to a disorder of the maturation process in the leukaemic cell line.
IntroductionNomenclaturePurificationand Genetic StructureCobalamin BindingReceptor BindingQuantification and OccurrenceDiseases Related to the Cobalamin Binding ProteinsFuture Perspectives
Granulocytes from a boy with congenital transcobalamin II (TC II) deficiency were found to have abnormally low antibacterial activity against Staphylococcus aureus. Transfusion of normal plasma supplemented with hydroxocobalamin temporarily restored granulocyte bactericidal activity to normal. Granulocyte function was also temporarily restored by oral leucovorin. The defect appears to be causally related to the patient's TC II deficiency and indirectly to an intracellular deficiency of cobalamin and folate coenzymes [1].
Incorporation of vitamin B12 into L1210 cells requires the protein binder transcobalamin II (TCII). The process is saturable, follows Michaelis-Menten kinetics (Km = 2.5 X 10(-9) M at 37 degrees C), is both temperature and calcium (K50 - 1 X 10(-6) M) dependent, and is inhibited by apo-TCII, indicating the presence of a TCII specific receptor on the cell membrane. B12 also leaves the cell by a calcium-independent pathway bound to either TCII or to a protein with chromatographic properties similar to those of TCIII. Since intact TCII-B12 can be found in the cytosol and can promote B12 uptake by mitochondria, it is proposed that the B12 released from the cell bound to the TCIII-like protein is derived by mitochondrial processing of incorporated TCII-B12. The slower time course of release of the latter B12 is consistent with this postulate.
One hundred and thirty-nine patients with non-hematologic malignancy were studied to define the incidence of vitamin B12-related abnormalities and correlate them with clinical findings. Based on vitamin B12-binding patterns, the following relatively distinct groups were defined: (A) 50% had normal results; (B) 6% had very high transcobalamin (TC) I and vitamin B12 levels as reported in isolated instances previously: most had hepatic metastases and early death, and all had definite metastatic disease; (C) 11% had high vitamin B12 levels with little or no unsaturated TC I elevation: most also had hepatic and other metastases and early death; (D) 23% had high vitamin B12-binding capacity with normal TC I and vitamin B12 levels: there were no distinguishing features for this group other than an increased proportion of black patients; and (E) 10% had low vitamin B12 levels, in many cases not associated with vitamin B12 deficiency or other known causes of low serum levels. Thus, high serum vitamin B12 level, with or without unsaturated TC I elevation, usually implies a poor prognosis in a patient with cancer. However, while most such patients have hepatic and other metastases, hepatic involvement was not universal nor did most patients with hepatic disease have high vitamin B12 levels. High serum TC I thus is not always due to increased granulocytic proliferation or to hepatic tumor, and alternative mechanisms for TC I accumulation should be sought.
A study of the three serum transcobalamins (TC) in myeloproliferative disorders and acute leukaemia has suggested a granulocyte origin for the three binders; the later stages of this cell line might be releasing 'TC I' and 'TC III' while 'TC II' which is increased in sera from patients with acute myelogenous leukaemia, probably originates at least in part from myeloblasts. The intracellular content of each TC has been studied in normal and leukaemic bone marrow cells after separation on a discontinuous bovine serum albumin gradient. Myeloblasts contain a TC II-like protein almost exclusively but promyelocytes contain a TC I-like protein which increases as the cells mature whilst 'TC II' decreases. A TC III-like binder parallels 'TC I' but appears later and reaches a maximum in the polymorphonuclear cells. In various types of leukaemia, abnormal TC distributions are related either to marrow replacement by the blast cells or to a disorder of the maturation process in the leukaemic cell line.
Sodium nitroprusside was investigated as a potential source of cyanide poisoning, Whole-blood cyanide determinations were performed on arterial samples from baboons receiving nitroprusside while anesthetized. There was a statistically significant increase in cyanide levels, as well as development of tachyphylaxis and severe metabolic acidosis. Hydroxocobalamin (vitamin B12a) infused simultaneously with nitroprusside significantly lessened the increase in cyanide levels and eliminated the development of metabolic acidosis. Nitroprusside can cause cyanide intoxication in the baboon, and hydroxocobalamin appears to be an effective antidote.
Recently in Japan, one form of vitamin B12, methylcobalamin also known as methyl B12, has attracted the attention of physicians as a therapy for patients with rheumatoid arthritis. However, its immunological actions in vivo are still unknown. In this study, we induced the in vitro production of such cytokines as interleukin-6 (IL-6), interferon-gamma (IFN-gamma), and interleukin-1 beta (IL-1 beta) by adding various mitogens (phytohemagglutinin:PHA, concanavalin A: ConA, or pokeweed mitogen:PWM) as well as recombinant interleukin-2, and we investigated the effects of methyl B12 (final concentration, 8-8,000 ng/ml) on the production of these cytokines by peripheral mononuclear cells. As compared to the controls, IL-6 production induced by PHA and ConA on Day 4 of the culture was suppressed by an average 60-70% when methyl B12 (80-8,000 ng/ml) was added to the medium. IFN-gamma production decreased dose-dependently with methyl B12, i.e., it decreased to 46% of the control when this production was induced by rIL-2, and decreased to 56-66% when it was induced by mitogens. The effect of methyl B12 on IL-1 beta production on Day I of the culture was small. These findings indicate that methyl B12 suppresses mainly the cytokine production of T lymphocytes. Such suppressive effects as shown in the in vitro situation are expected to be expressed also in vivo in patients with rheumatoid arthritis, especially at articulation lesion sites.
Transcobalamin I (TCI) is a vitamin B12 binding protein that is found in the secondary granules of mature neutrophils. The expression of the gene for TCI (TCN1) within neutrophils has been shown to be restricted to the later stages of myeloid development and can therefore be used as a marker for granulocyte differentiation. To study transcriptional control regions important in late stage myeloid gene regulation the genomic sequence for TCN1 has been cloned. Clones were isolated from a genomic library constructed in Charon 4A using homologous full-length cDNA probes. Southern blot analysis showed the gene to reside on five EcoRI fragments totaling 14 kb in length. Two overlapping phage clones, containing the entire 14 kb, were isolated and the introns and exons were mapped using Southern blotting and dideoxy sequencing of subclones. The cDNA is represented by nine exons contained within 12 kb of genomic DNA. Comparison of the genomic structure to gastric intrinsic factor (GIF), another vitamin B12 binding protein, revealed a strikingly similar intron/exon structure, with several positionally conserved splice sites. The gene was localized to chromosome 11 using in situ hybridization.
The aim was to investigate the effects of NG-monomethyl-L-arginine (L-NMMA), an inhibitor of both the constitutive (Ca2+ dependent) and inducible (Ca2+ independent) nitric oxide (NO) synthases, or of pretreatment with the glucocorticoid dexamethasone, an inhibitor of the induction of the Ca2+ independent NO synthase, on lipopolysaccharide induced shock in the anaesthetised rabbit.
Mean arterial blood pressure, and blood flow in the portal vein, hepatic artery, and hindquarter vascular beds were measured in 49 halothane anaesthetised New Zealand White rabbits given lipopolysaccharide (Salmonella minnesota, 500 micrograms.kg-1 intravenously). The effects of pre- or post-lipopolysaccharide treatment with L-NMMA (300 mg.kg-1 intravenously) and of pretreatment with dexamethasone (3 mg.kg-1 intravenously) were determined. The effect of the NO donor S-nitroso-N-acetyl-penicillamine (SNAP, 300 micrograms.kg-1.h-1 intravenously) in animals treated with lipopolysaccharide and L-NMMA was also studied.
Lipopolysaccharide elicited an initial transient fall in mean arterial pressure and decreases in blood flow in the vascular beds, followed by a progressive fall in mean arterial pressure. L-NMMA when given either before or after lipopolysaccharide markedly exacerbated its effects and resulted in severe hypotension, intense vasoconstriction, and increased mortality. Pretreatment with dexamethasone had no effect on the initial haemodynamic changes following lipopolysaccharide, but prevented the subsequent fall in mean arterial pressure observed in animals treated with lipopolysaccharide alone. Dexamethasone failed, however, to protect animals also treated with L-NMMA before lipopolysaccharide. Animals pretreated with L-NMMA and SNAP showed reduced haemodynamic changes when compared with controls (lipopolysaccharide only) or lipopolysaccharide and L-NMMA treated animals.
Inhibition of both constitutive and inducible NO synthases during endotoxaemia is deleterious. This can be overcome by replacing NO intravenously with a donor of NO. Selective inhibition of the inducible NO synthase may, however, be beneficial in shock.