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American Journal of TherapeuticsVitamin B6 is essential for life and plays a critical role in many biochemical and physiological processes in the human body. The term B6 collectively refers to 6...
BACKGROUND
Vitamin B6 is essential for life and plays a critical role in many biochemical and physiological processes in the human body. The term B6 collectively refers to 6 water-soluble vitamers, and only the pyridoxal 5'-phosphate (PLP) serves as the biologically active form. A plasma PLP concentration above 30 nmol/L (7.4 μg/L) is indicative of an adequate vitamin B6 status for all age and sex groups. The currently recommended daily allowance of B6 (1.5-2 mg/d) from dietary sources frequently results in inadequate B6 status (<20 nmol/L or 5 μg/L) in many elderly patients and patients with comorbid conditions. PLP-based supplements are preferred and should be administered weekly in low doses (50-100 mg) to maintain a stable serum PLP level between 30 and 60 nmol/L or 7.4 and 15 μg/L.
AREAS OF UNCERTAINTY
It is challenging for physicians to prescribe a safe dose of B6 supplements because of the narrow therapeutic index. The association between elevated levels of pyridoxine and neuropathy is not well established. PLP-based supplements are shown to be least neurotoxic, but further clinical trials are needed to establish the long-term safety in high doses.
DATA SOURCES
PubMed search of randomized control trials and meta-analyses.
THERAPEUTIC OPINION
Plasma B6 levels should be ordered as a part of workup of any unexplained anemia before labeling as "anemia of chronic disease." B6 supplementation is also crucial in the management of chronic Mg deficiency resistant to therapy. When B6 is administered daily in supraphysiologic doses, there is a potential for the development of neurotoxicity (typically at levels >100 nmol/L or 25 μg/L). PLP-based supplements are preferred over pyridoxine supplements because of minimal neurotoxicity observed in neuronal cell viability tests. Since B6 metabolites have a long half-life, weekly administration is preferred over daily use to prevent toxicity.
Topics: Humans; Aged; Pyridoxine; Vitamin B 6; Pyridoxal Phosphate; Dietary Supplements
PubMed: 36608063
DOI: 10.1097/MJT.0000000000001460 -
International Journal of Molecular... May 2020Vitamin B6 is a cofactor for approximately 150 reactions that regulate the metabolism of glucose, lipids, amino acids, DNA, and neurotransmitters. In addition, it plays... (Review)
Review
Vitamin B6 is a cofactor for approximately 150 reactions that regulate the metabolism of glucose, lipids, amino acids, DNA, and neurotransmitters. In addition, it plays the role of antioxidant by counteracting the formation of reactive oxygen species (ROS) and advanced glycation end-products (AGEs). Epidemiological and experimental studies indicated an evident inverse association between vitamin B6 levels and diabetes, as well as a clear protective effect of vitamin B6 on diabetic complications. Interestingly, by exploring the mechanisms that govern the relationship between this vitamin and diabetes, vitamin B6 can be considered both a cause and effect of diabetes. This review aims to report the main evidence concerning the role of vitamin B6 in diabetes and to examine the underlying molecular and cellular mechanisms. In addition, the relationship between vitamin B6, genome integrity, and diabetes is examined. The protective role of this vitamin against diabetes and cancer is discussed.
Topics: Animals; DNA Damage; Diabetes Mellitus; Glycation End Products, Advanced; Humans; Vitamin B 6
PubMed: 32456137
DOI: 10.3390/ijms21103669 -
Journal of Hepatology Oct 2023We previously demonstrated that people with primary sclerosing cholangitis (PSC) had reduced gut microbial capacity to produce active vitamin B6 (pyridoxal 5'-phosphate...
BACKGROUND AND AIMS
We previously demonstrated that people with primary sclerosing cholangitis (PSC) had reduced gut microbial capacity to produce active vitamin B6 (pyridoxal 5'-phosphate [PLP]), which corresponded to lower circulating PLP levels and poor outcomes. Here, we define the extent and biochemical and clinical impact of vitamin B6 deficiency in people with PSC from several centers before and after liver transplantation (LT).
METHODS
We used targeted liquid chromatography-tandem mass spectrometry to measure B6 vitamers and B6-related metabolic changes in blood from geographically distinct cross-sectional cohorts totaling 373 people with PSC and 100 healthy controls to expand on our earlier findings. Furthermore, we included a longitudinal PSC cohort (n = 158) sampled prior to and serially after LT, and cohorts of people with inflammatory bowel disease (IBD) without PSC (n = 51) or with primary biliary cholangitis (PBC) (n = 100), as disease controls. We used Cox regression to measure the added value of PLP to predict outcomes before and after LT.
RESULTS
In different cohorts, 17-38% of people with PSC had PLP levels below the biochemical definition of a vitamin B6 deficiency. The deficiency was more pronounced in PSC than in IBD without PSC and PBC. Reduced PLP was associated with dysregulation of PLP-dependent pathways. The low B6 status largely persisted after LT. Low PLP independently predicted reduced LT-free survival in both non-transplanted people with PSC and in transplant recipients with recurrent disease.
CONCLUSIONS
Low vitamin B6 status with associated metabolic dysregulation is a persistent feature of PSC. PLP was a strong prognostic biomarker for LT-free survival both in PSC and recurrent disease. Our findings suggest that vitamin B6 deficiency modifies the disease and provides a rationale for assessing B6 status and testing supplementation.
IMPACT AND IMPLICATIONS
We previously found that people with PSC had reduced gut microbial potential to produce essential nutrients. Across several cohorts, we find that the majority of people with PSC are either vitamin B6 deficient or have a marginal deficiency, which remains prevalent even after liver transplantation. Low vitamin B6 levels strongly associate with reduced liver transplantation-free survival as well as deficits in biochemical pathways dependent on vitamin B6, suggesting that the deficiency has a clinical impact on the disease. The results provide a rationale for measuring vitamin B6 and to investigate whether vitamin B6 supplementation or modification of the gut microbial community can help improve outcomes for people with PSC.
Topics: Humans; Vitamin B 6 Deficiency; Cholangitis, Sclerosing; Cross-Sectional Studies; Vitamin B 6; Inflammatory Bowel Diseases; Liver
PubMed: 37328069
DOI: 10.1016/j.jhep.2023.05.038 -
Clinica Chimica Acta; International... Jul 2016Homocystinuria is a disorder of sulfur metabolism pathway caused by deficiency of cystathionine β-synthase (CBS). It is characterized by increased accumulation of... (Review)
Review
Homocystinuria is a disorder of sulfur metabolism pathway caused by deficiency of cystathionine β-synthase (CBS). It is characterized by increased accumulation of homocysteine (Hcy) in the cells and plasma. Increased homocysteine results in various vascular and neurological complications. Present strategies to lower cellular and plasma homocysteine levels include vitamin B6 intake, dietary methionine restriction, betaine supplementation, folate and vitamin B12 administration. However, these strategies are inefficient for treatment of homocystinuria. In recent years, advances have been made towards developing new strategies to treat homocystinuria. These mainly include functional restoration to mutant CBS, enhanced clearance of Hcy from the body, prevention of N-homocysteinylation-induced toxicity and inhibition of homocysteine-induced oxidative stress. In this review, we have exclusively discussed the recent advances that have been achieved towards the treatment of homocystinuria. The review is an attempt to help clinicians in developing effective therapeutic strategies and designing novel drugs against homocystinuria.
Topics: Betaine; Cystathionine beta-Synthase; Homocystinuria; Humans; Hydrogen-Ion Concentration; Oxidative Stress; Small Molecule Libraries; Vitamin B 12; Vitamin B 6
PubMed: 27059523
DOI: 10.1016/j.cca.2016.04.002 -
Journal of the National Cancer Institute Mar 2017Vitamin B6 is involved in many biochemical reactions and might play a role in carcinogenesis. We summarized the evidence linking vitamin B6 to cancer risk. (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Vitamin B6 is involved in many biochemical reactions and might play a role in carcinogenesis. We summarized the evidence linking vitamin B6 to cancer risk.
METHODS
We conducted a systematic review of both observational and intervention studies investigating the relationship between vitamin B6 intake or blood levels of its bioactive form pyridoxal-5'-phosphate (PLP) and the risk of any type of cancer. Random-effects meta-analysis was used to calculate pooled relative risks (RRs) and their 95% confidence intervals (CIs) across studies for high vs low categories of vitamin intake or PLP levels. We also performed a random-effects dose-response meta-analysis.
RESULTS
We identified 121 observational studies (participants, n = 1 924 506; cases, n = 96 , 436) and nine randomized controlled trials (RCTs; participants, n = 34 911; cases, n = 2539) considering 19 tumor sites. High intake of dietary (food only) vitamin B6 was statistically significantly associated with lower risk of all cancers (relative risk [RR] = 0.78, 95% CI = 0.73 to 0.84) and specific tumors, with special regard to gastrointestinal carcinomas (RR = 0.68, 95% CI = 0.61 to 0.75). An inverse association was also observed between high PLP levels and the risk of all cancers (RR = 0.66, 95% CI = 0.58 to 0.76) and single tumor sites, the most consistent results being those for gastrointestinal tumors (RR = 0.56, 95% CI = 0.48 to 0.65). There was a statistically significant inverse linear relationship between cancer risk and both vitamin B6 dietary intake and PLP levels. When total (food and supplements) intake was considered, the associations were weaker or null. Findings from RCTs did not support a protective effect of vitamin B6 against cancer, although this evidence was graded as low level.
CONCLUSIONS
Epidemiological evidence supports the potential of vitamin B6 as a cancer risk reduction agent and the role of PLP as a cancer screening biomarker, especially for gastrointestinal tumors. However, inconsistent findings from total intake and intervention studies suggest that vitamin B6 might also be an indicator of other dietary protective micronutrients.
Topics: Diet; Dose-Response Relationship, Drug; Humans; Neoplasms; Observational Studies as Topic; Protective Factors; Pyridoxal Phosphate; Randomized Controlled Trials as Topic; Risk Assessment; Vitamin B 6
PubMed: 28376200
DOI: 10.1093/jnci/djw230 -
BMC Musculoskeletal Disorders Jun 2024Although various anti-inflammatory medicines are widely recommended for osteoarthritis (OA) treatment, no significantly clinical effect has been observed. This study...
BACKGROUND
Although various anti-inflammatory medicines are widely recommended for osteoarthritis (OA) treatment, no significantly clinical effect has been observed. This study aims to examine the effects of vitamin B6, a component that has been reported to be capable of alleviating inflammation and cell death in various diseases, on cartilage degeneration in OA.
METHODS
Collagen-induced arthritis (CIA) mice model were established and the severity of OA in cartilage was determined using the Osteoarthritis Research Society International (OARSI) scoring system. The mRNA and protein levels of indicators associated with extracellular matrix (ECM) metabolism, apoptosis and inflammation were detected. The effect of vitamin B6 (VB6) on the mice were assessed using HE staining and masson staining. The apoptosis rate of cells was assessed using TdT-mediated dUTP nick end labeling.
RESULTS
Our results showed a trend of improved OARSI score in mice treated with VB6, which remarkably inhibited the hyaline cartilage thickness, chondrocyte disordering, and knees hypertrophy. Moreover, the VB6 supplementation reduced the protein expression of pro-apoptosis indicators, including Bax and cleaved caspase-3 and raised the expression level of anti-apoptosis marker Bcl-2. Importantly, VB6 improved ECM metabolism in both in vivo and in vitro experiments.
CONCLUSIONS
This study demonstrated that VB6 alleviates OA through regulating ECM metabolism, inflammation and apoptosis in chondrocytes and CIA mice. The findings in this study provide a theoretical basis for targeted therapy of OA, and further lay the theoretical foundation for studies of mechanisms of VB6 in treating OA.
Topics: Animals; Apoptosis; Mice; Vitamin B 6; Osteoarthritis; Arthritis, Experimental; Inflammation; Male; Chondrocytes; Mice, Inbred DBA; Anti-Inflammatory Agents; Extracellular Matrix; Cartilage, Articular
PubMed: 38844896
DOI: 10.1186/s12891-024-07530-x -
Advances in Food and Nutrition Research 2018Vitamin B6 serves as a coenzyme catalyzing more than 150 enzymes regulating metabolism and synthesis of proteins, carbohydrates, lipids, heme, and important bioactive... (Review)
Review
Vitamin B6 serves as a coenzyme catalyzing more than 150 enzymes regulating metabolism and synthesis of proteins, carbohydrates, lipids, heme, and important bioactive metabolites. For several years vitamin B6 and its vitamers (B6) were recognized as antioxidant and antiinflammatory and in modulating immunity and gene expression. During the last 10 years, there were growing reports implicating B6 in inflammation and inflammation-related chronic illnesses including cancer. It is unclear if the deficiency of B6 or additional intake of B6, above the current requirement, should be the focus. Whether the current recommended daily intake for B6 is adequate should be revisited, since B6 is important to human health beyond its role as a coenzyme and its status is affected by many factors including but not limited to age, obesity, and inflammation associated with chronic illnesses. A link between inflammation B6 status and carcinogenesis is not yet completely understood. B6-mediated synthesis of HS, a gasotransmitter, and taurine in health and disease, especially in maintaining mitochondrial integrity and biogenesis and inflammation, remains an important area to be explored. Recent developments in the molecular role of B6 and its direct interaction with inflammasomes, and nuclear receptor corepressor and coactivator, receptor-interacting protein 140, provide a strong impetus to further explore the multifaceted role of B6 in carcinogenesis and human health.
Topics: Animals; Carcinogenesis; Humans; Inflammation; Vitamin B 6; Vitamin B 6 Deficiency; Vitamins
PubMed: 29477221
DOI: 10.1016/bs.afnr.2017.11.004 -
Cellular & Molecular Immunology Jul 2023Interleukin-33 (IL-33) is a crucial nuclear cytokine that induces the type 2 immune response and maintains immune homeostasis. The fine-tuned regulation of IL-33 in...
Interleukin-33 (IL-33) is a crucial nuclear cytokine that induces the type 2 immune response and maintains immune homeostasis. The fine-tuned regulation of IL-33 in tissue cells is critical to control of the type 2 immune response in airway inflammation, but the mechanism is still unclear. Here, we found that healthy individuals had higher phosphate-pyridoxal (PLP, an active form of vitamin B6) concentrations in the serum than asthma patients. Lower serum PLP concentrations in asthma patients were strongly associated with worse lung function and inflammation. In a mouse model of lung inflammation, we revealed that PLP alleviated the type 2 immune response and that this inhibitory effect relied on the activity of IL-33. A mechanistic study showed that in vivo, pyridoxal (PL) needed to be converted into PLP, which inhibited the type 2 response by regulating IL-33 stability. In mice heterozygous for pyridoxal kinase (PDXK), the conversion of PL to PLP was limited, and IL-33 levels were increased in the lungs, aggravating type 2 inflammation. Furthermore, we found that the mouse double minute 2 homolog (MDM2) protein, an E3 ubiquitin-protein ligase, could ubiquitinate the N-terminus of IL-33 and sustain IL-33 stability in epithelial cells. PLP reduced MDM2-mediated IL-33 polyubiquitination and decreased the level of IL-33 through the proteasome pathway. In addition, inhalation of PLP alleviated asthma-related effects in mouse models. In summary, our data indicate that vitamin B6 regulates MDM2-mediated IL-33 stability to constrain the type 2 response, which might help develop a potential preventive and therapeutic agent for allergy-related diseases.
Topics: Mice; Animals; Vitamin B 6; Interleukin-33; Pyridoxal; Inflammation; Asthma; Disease Models, Animal; Homeostasis
PubMed: 37217797
DOI: 10.1038/s41423-023-01029-6 -
Biotechnology Advances 2017Vitamin B6 is a designation for the six vitamers pyridoxal, pyridoxine, pyridoxamine, pyridoxal 5'-phosphate (PLP), pyridoxine 5'-phosphate, and pyridoxamine. PLP, being... (Review)
Review
Vitamin B6 is a designation for the six vitamers pyridoxal, pyridoxine, pyridoxamine, pyridoxal 5'-phosphate (PLP), pyridoxine 5'-phosphate, and pyridoxamine. PLP, being the most important B6 vitamer, serves as a cofactor for many proteins and enzymes. In contrast to other organisms, animals and humans have to ingest vitamin B6 with their food. Several disorders are associated with vitamin B6 deficiency. Moreover, pharmaceuticals interfere with metabolism of the cofactor, which also results in vitamin B6 deficiency. Therefore, vitamin B6 is a valuable compound for the pharmaceutical and the food industry. Although vitamin B6 is currently chemically synthesized, there is considerable interest on the industrial side to shift from chemical processes to sustainable fermentation technologies. Here, we review recent findings regarding biosynthesis and homeostasis of vitamin B6 and describe the approaches that have been made in the past to develop microbial production processes. Moreover, we will describe novel routes for vitamin B6 biosynthesis and discuss their potential for engineering bacteria that overproduce the commercially valuable substance. We also highlight bottlenecks of the vitamin B6 biosynthetic pathways and propose strategies to circumvent these limitations.
Topics: Bacillus subtilis; Escherichia coli; Fermentation; Industrial Microbiology; Metabolic Engineering; Vitamin B 6
PubMed: 27890703
DOI: 10.1016/j.biotechadv.2016.11.004 -
Aging Clinical and Experimental Research Apr 2023Gain insight into the impact of B vitamins, including vitamin B1, vitamin B2, niacin, vitamin B6, total folate, and vitamin B12 on the risk of frailty in patients with...
PURPOSE
Gain insight into the impact of B vitamins, including vitamin B1, vitamin B2, niacin, vitamin B6, total folate, and vitamin B12 on the risk of frailty in patients with chronic obstructive pulmonary disease (COPD).
METHODS
This study was an American population-based cross-sectional study using data from the National Health and Nutrition Examination Survey (NHANES). A total of 1201 COPD patients were included in the analysis. Of these, the intake of B vitamins was determined by the two 24-h recall interviews. We followed the method constructed by Hakeem et al. to calculate the frailty index (FI), which is used as a reliable tool to assess the debilitating status of patients with COPD. Missing data were imputed by the MissForest method based on random forests. Multivariate logistic regression model and inverse probability weighted based on propensity scores were used to correct for confoundings.
RESULTS
Logistic regression models showed that vitamin B6 intake was negatively correlated with frailty risk in COPD patients, while other B vitamins including B1, B2, niacin (vitamin B3), total folic acid and vitamin B12 were not. After adjusting for covariates, the association between vitamin B6 and frailty risk (adjusted OR = 0.80, 95%CI = 0.66-0.95, P = 0.013) remained significant. At the same time, sensitivity analysis proves the robustness of the results.
CONCLUSION
COPD patients with lower vitamin B6 intake have a higher risk of frailty. However, intake of vitamin B1, B2, niacin, total folic acid, and vitamin B12 was not associated with frailty risk in COPD patients.
Topics: Humans; Aging; Pulmonary Disease, Chronic Obstructive; Vitamin B 6; Frailty; Niacin; Vitamin B Complex; Male; Female; Aged; Aged, 80 and over
PubMed: 36719551
DOI: 10.1007/s40520-023-02353-7