Plasma Pyridoxal Phosphate Levels Research Articles

Effects of maternal vitamin deficiency on the microstructure of the maternal hippocampus and behavior in offspring

ObjectivesNutrition plays a critical role in the brain's function and development. Vitamin B6 in the form of pyridoxal phosphate (PLP) is required for the biosynthesis of several neurotransmitters. As vitamin B6 is not endogenously synthesized, the availability of dietary sources becomes imperative. Due to its contribution to neurological functions, severe vitamin B6 deficiency leads to an increased risk of psychiatric disorders, dementia, and neurodevelopmental disorders. This study aimed to establish a vitamin B6-deficient model in experimental animals and assess the neurodevelopmental effects in their offspring. MethodsTwo- to three-month-old female C57BL/6J mice were used in the study. They were randomly divided into control and vitamin B6-deficient groups. The control group was fed a regular diet containing 6 mg vitamin B6/kg and the vitamin B6-deficient group was fed a customized diet containing 0 mg vitamin B6/kg, for 5 weeks (n = 6). After 5 weeks, plasma PLP was assessed. The animals were bred to generate offspring. The dams were killed following weaning, and the hippocampal neurons were quantified using cresyl violet staining. The offspring were assigned the respective diet post-weaning up to 2 months of age. Learning and memory were assessed using the Morris water maze test. ResultsThe plasma PLP levels confirmed the deficiency in the deficient group compared to the control group. The viable pyramidal neurons in the cornu ammonis 3 (CA3) region of the hippocampus showed a significant difference between the control and deficient groups. Offspring born to deficient dams showed a substantial increase in latency to reach the target quadrant during the probe trial compared to the controls. ConclusionVitamin B6 deficiency reduces memory in dams and their offspring, suggesting the importance of vitamin B6 for both brain function and development.

Urine phosphoethanolamine is a specific biomarker for hypophosphatasia in adults.

We investigated the utility of urine phosphoethanolamine (PEA) as a marker to aid in diagnosing and/or confirming hypophosphatasia (HPP) in adults and for monitoring patients on enzyme replacement therapy (ERT). Data was collected from seventy-eight adults who were referred to the Vanderbilt Program for Metabolic Bone Disease for evaluation of a possible or confirmatory HPP diagnosis between July 2014 through December 2019. Fifty-nine patients were diagnosed with HPP and nineteen were excluded from a diagnosis of HPP. The urine PEA results of those patients with a confirmed diagnosis of HPP and those patients with a diagnosis of HPP excluded were captured and compared to other laboratory and clinical parameters consistent with HPP, including alkaline phosphatase (ALP) activity, plasma pyridoxal 5'-phosphate (PLP), the presence of musculoskeletal abnormalities, and genetic testing for pathogenic mutations in ALPL. Initial urine PEA values in patients in our HPP cohort and not on ERT were significantly higher (median=150.0nmol/mg creatinine, IQR=82.0-202.0) compared patients in our HPP negative group (median 18.0nmol/mg creatinine, IQR=14.0-30.0, p<0.0001) and higher than patients on ERT (median 65.0nmol/mg creatinine, IQR=45.3-79.8). Patients who began ERT had a decline in urine PEA levels after treatment with a mean decrease of 68.1%. Plasma ALP levels were significantly lower in the group of patients with HPP and not on ERT group (median=24.0U/L, IQR=15.0-29.50) compared to the patients without HPP (median=45.50U/L, IQR=34.0-62.0;) and plasma PLP levels were significantly higher in the HPP non-ERT group (median=284.0nmol/L, IQR=141.0-469.4) compared to the patients without HPP (median=97.5nmol/L, IQR=43.7-206.0;). The area under the curve (AUC) of urine PEA, ALP, and PLP to distinguish between HPP and non-HPP patients is 0.968, 0.927 and 0.781, respectively, in our cohort. Urine PEA had 100% specificity (95% CI of 83.2% to 100.0%) for diagnosing HPP at a value >53.50nmol/mg creatinine with a sensitivity of 88.4%; 95%CI 75.5 to 94.9%. ALP had a 100% specificity (95% CI of 82.4% to 100.0%) for diagnosing HPP at a value <30.5U/L with a sensitivity of 77.2%; (95%CI 64.8 to 86.2%). PLP had a 100% specificity (95% CI of 81.6% to 100.0%) for diagnosing HPP at a value >436nmol/L with a sensitivity of 26.9%; (95%CI 16.8 to 40.3%). The most common pathogenic or likely pathogenic mutations in our cohort were c.1250A>G (p.Asn417Ser), c.1133A>T (p.Asp378Val), c.881A>C (p.Asp294Ala), c.1171C>T (p.Arg391Cys), and c.571G>A, (p.Glu191Lys). Urine PEA is a promising diagnostic and confirmatory marker for HPP in patients undergoing investigation for HPP. Urine PEA also has potential use as a marker to monitor ERT compliance. Future studies are necessary to evaluate the association between PEA levels and clinical outcomes.

Associations of Vitamin B6 Intake and Plasma Pyridoxal 5'-Phosphate with Plasma Polyunsaturated Fatty Acids in US Older Adults: Findings from NHANES 2003-2004.

Previous evidence suggests a potential dual impact of aging and vitamin B6 (B6) deficiency on polyunsaturated fatty acid (PUFA) metabolism; gender may influence PUFA biosynthesis. Perturbation of PUFA compositions during B6 deficiency could be linked to age-related health outcomes. However, little is known about the interrelationships between vitamin B6, PUFA, and gender in the older population. Therefore, we investigated whether gender-specific associations of B6 intake and plasma pyridoxal 5’-phosphate (PLP) concentration, respectively, with plasma PUFA concentrations and ratios (eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), arachidonic acid (AA), EPA + DHA, EPA/AA, and (EPA + DHA)/AA) existed in older adults. We further examined the relationships of adequate B6 status (PLP ≥ 20 nmol/L) with high (above median) plasma PUFA relative to deficient B6 status. This cross-sectional study analyzed 461 participants aged ≥60 years from NHANES 2003–2004. Nutrient intakes were assessed using two 24-h recalls and supplement questionnaires. PLP and PUFA concentrations were measured. Multivariate linear regression assessed the association of B6 intake and PLP with PUFA; multivariate logistic regression evaluated the relationship of adequate B6 status with high plasma PUFA, adjusting for demographic, socioeconomic, and dietary factors; physical activity; smoking; alcohol; medication; and BMI. There were interactions between gender and B6 intake on EPA (P-interaction = 0.008) and AA (P-interaction = 0.004) only, whereas no interaction existed between gender and PLP on PUFA. PLP was directly associated with EPA (β = 0.181, P = 0.002), DHA (β = 0.109, P = 0.005), EPA + DHA (β = 0.14, P = 0.002), EPA/AA (β = 0.186, P = 0.004), and (EPA + DHA)/AA (β = 0.13, P = 0.026). The odds of having high plasma EPA (adjusted (a) OR: 2.03, P = 0.049) and EPA/AA (aOR: 3.83, P < 0.0001) were greater in those with adequate B6 status compared to those with deficient B6 status. In conclusion, in US older adults, a higher PLP level was associated with a greater level of EPA, DHA, EPA + DHA, EPA/AA, and (EPA + DHA)/AA. Adequate B6 status was associated with high EPA and EPA/AA status. These findings suggest that sufficient vitamin B6 status may positively influence PUFA metabolism in older adults.

Vitamin B6 deficiency with normal plasma levels of pyridoxal 5'-phosphate in perinatal hypophosphatasia.

Pyridoxal 5'-phosphate (PLP), the principal circulating form of vitamin B6 (B6), is elevated in the plasma of individuals with hypophosphatasia (HPP). HPP is the inborn-error-of-metabolism caused by loss-of-function mutation(s) of ALPL, the gene that encodes the "tissue-nonspecific" isoenzyme of alkaline phosphatase (TNSALP). PLP accumulates extracellularly in HPP because it is a natural substrate of this cell-surface phosphomonoester phosphohydrolase. Even individuals mildly affected by HPP manifest this biochemical hallmark, which is used for diagnosis. Herein, an exclusively breast-fed newborn boy with life-threatening perinatal HPP had uniquely normal instead of markedly elevated plasma PLP levels before beginning asfotase alfa (AA) TNSALP-replacement therapy. These abnormal PLP levels were explained by B6 deficiency, confirmed by his low plasma level of 4-pyridoxic acid (PA), the B6 degradation product. His mother, a presumed carrier of one of his two ALPL missense mutations, had serum ALP activity of 50U/L (Nl 40-130) while her plasma PLP level was 9 μg/L (Nl 5-50) and PA was 3 μg/L (Nl 3-30). Her dietary history and breast milk pyridoxal (PL) level indicated she too was B6 deficient. With B6 supplementation using a breast milk fortifier, the patient's plasma PA level corrected, while his PLP level remained in the normal range but now in keeping with AA treatment. Our experience reveals that elevated levels of PLP in the circulation in HPP require some degree of B6 sufficiency, and that anticipated increases in HPP can be negated by hypovitaminosis B6.

Association of Polyunsaturated Fatty Acids and Vitamin B6 with Inflammation in Adults from the National Health and Nutrition Examination Survey (NHANES) 2003–2004

Abstract Objectives Polyunsaturated fatty acids (PUFA) such as n-3 PUFA, eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and n-6 PUFA, arachidonic acid (AA) may mediate inflammatory responses. Vitamin B6 deficiency has been shown to alter plasma PUFA levels. This perturbation of PUFA metabolism in vitamin B6 deficiency measured by pyridoxal-5’-phosphate (PLP) may contribute to inflammation. Thus, we aimed to examine the associations of 1) dietary EPA + DHA, and vitamin B6 with plasma ratio of AA/(EPA + DHA) by PLP level, 2) plasma AA/(EPA + DHA) and PLP with C-reactive protein (CRP), a marker for inflammation, and 3) dietary EPA + DHA, and vitamin B6 with CRP level, using NHANES. Methods NHANES datasets (2003–2004) with subjects ≥20 years were analyzed, accounting for survey design and sample weights (n = 4486). The significance level was P &amp;lt; 0.05. Covariates were age, gender, ethnicity, BMI, smoking, alcohol, total energy, dietary supplements, physical activity, and NSAIDs, depending on analyses. Multiple linear regression assessed the association of dietary EPA + DHA, and vitamin B6 with plasma ratio of AA/(EPA + DHA) by PLP level (Low: &amp;lt; 20 nmol/L, High: ≥20 nmol/L). Next, multivariate logistic regression predicted the associations of plasma AA/(EPA + DHA) and PLP with CRP level (Low: ≤3 mg/L, Moderate to High: &amp;gt; 3 mg/L); then, dietary EPA + DHA, and B6 with CRP level. Results In the low PLP level, dietary EPA + DHA was negatively associated with plasma ratio of AA/(EPA + DHA) (B = ─5.29, SE = 0.84, P = &amp;lt; .0001), but B6 intake was not, whereas, in the high PLP level, both dietary EPA + DHA (B = ─2.99, SE = 0.53, P = &amp;lt; .0001) and dietary vitamin B6 (B = ─0.21, SE = 0.04, P = 0.0001) were inversely associated with plasma AA/(EPA + DHA). Further, low PLP level was associated with greater odds of moderate to high CRP level compared to high PLP level (adjusted OR (aOR): 2.8, 95% CI: 1.93–4.04, P = &amp;lt; .0001), but plasma AA/(EPA + DHA) was not. In addition, both dietary EPA + DHA (aOR: 0.5, 95% CI: 0.23–0.98, P = 0.04) and vitamin B6 (aOR: 0.8, 95% CI: 0.68–0.95, P = 0.009) were inversely associated with moderate to high CRP level. Conclusions Our findings show that low plasma PLP level and low vitamin B6 intake are associated with inflammation, and the relationship may be through their effect on PUFA metabolism, suggesting that increased intake of vitamin B6 and EPA and DHA may protect against inflammation. Funding Sources N/A.

Plasma B-vitamin and one-carbon metabolites and risk of breast cancer before and after folic acid fortification in the United States.

Prior epidemiologic findings for plasma folate and B-vitamins and breast cancer risk are inconsistent and have not assessed the influence of folic acid fortification. Therefore, we examined the associations of plasma folate, B12 , pyridoxal 5'-phosphate (PLP), homocysteine, cysteine and cysteinylglycine with breast cancer risk, before and after fortification. We conducted a nested case-control study within the prospective Nurses' Health Study. In 1989-1990 (pre-fortification), 32,826 women donated a blood sample and 18,743 donated an additional blood sample in 2000-2001 (post-fortification). Between the first blood collection and 2006, 1874 incident breast cancer cases with at least one blood sample and 367 with two were 1:1 matched to controls. Conditional logistic regression was used to estimate relative risks (RR) and 95% confidence intervals (CI) adjusting for breast cancer risk factors. Overall, higher plasma folate, B12 , PLP, homocysteine, cysteine and cysteinylglycine levels were not associated with breast cancer risk. Associations did not vary by in situ/invasive, hormone receptor status, or tumor molecular subtype. Additionally, associations were null before and after fortification. For example, the RR (95% CI) for the highest versus lowest tertile of 1990 (pre-fortification) plasma folate with 1990-2000 follow-up was 0.93 (0.75-1.16) and for the 2000 plasma folate (post-fortification) with 2000-2006 follow-up the RR (95% CI) was 1.17 (0.79-1.74). Plasma folate, B12 , PLP, homocysteine, cysteine and cysteinylglycine were not significantly associated with breast cancer overall, before and after fortification, or with specific tumor molecular subtypes. However, long term associations (>8 years) after the implementation of fortification could not be examined.

Plasma Pyridoxal 5´-Phosphate Level in Children with Intractable and Controlled Epilepsy.

Intractable epilepsy is a serious neurologic problem with different etiologies. Decreased levels of pyridoxal phosphate in cerebral spinal fluid of patients with intractable epilepsy due to pyridoxine dependency epilepsy are reported. The aim of this study was to compare plasma pyridoxal 5´-phosphate level in patients with intractable and controlled epilepsy. This cross- sectional analytic study included 66 epileptic children, 33 patients with controlled and 33 patients with intractable epilepsy, after neonatal period up to 15 yr old of age. Thirty-three patients with intractable epilepsy (10- 162 months) and 33 patients with controlled epilepsy (14-173 months) were enrolled. The study was conducted in Pediatric Neurology Clinic of Mofid Children Hospital, Tehran, Iran from January 2010 to December 2010. Patients' clinical manifestations, laboratory and neuroimaging findings were collected. Non-fasting plasma 5´- pyridoxal phosphate levels of these subjects were assessed by high-pressure liquid chromatography. Mean plasma 5´- pyridoxal phosphate level (PLP) in patients with controlled epilepsy was 76.78±37.24 (nmol/l) (15.5-232.4). In patients with intractable epilepsy, mean plasma 5´- pyridoxal phosphate was 98.67± 80.58 (25.5- 393) nmol/l. There was no statistically significant difference between plasma pyridoxal phosphate levels of these two groups (P═0.430). Pyridoxine dependent epilepsy is under diagnosed because it is manifested by various types of seizures. Plasma pyridoxal phosphate levels did not differ in our patients with intractable or controlled epilepsy. If PDE is suspected on clinical basis, molecular investigation of ALDH7A1 mutations, as feasible test, until PDE biomarkers becomes available is recommended.

Vitamin B-6, Independent of Homocysteine, Is a Significant Factor in Relation to Inflammatory Responses for Chronic Kidney Disease and Hemodialysis Patients.

The purpose of this study was to investigate whether plasma pyridoxal 5′-phosphate (PLP) and homocysteine were dependent on or independent of each other in order to be associated with inflammatory markers in patients with chronic kidney disease (CKD) or those receiving hemodialysis treatment. This was a cross-sectional study. Sixty-eight stage 2–5 CKD patients and 68 hemodialysis patients had one time fasting blood drawn for measurements of plasma PLP, pyridoxal (PL), homocysteine, and several inflammatory markers. Early CKD stage (stages 2-3) patients showed significantly lower plasma PLP levels and homocysteine concentrations than patients in an advanced CKD stage (stages 4-5) and those undergoing hemodialysis. Plasma PLP significantly correlated with CRP levels (partial rs = −0.21, p < 0.05) and plasma PL significantly correlated with IL-10 levels (partial rs = −0.24, p < 0.01), while plasma PLP plus PL significantly correlated with both CRP levels (partial rs = −0.20, p < 0.05) and interleukin-1β (partial rs = 0.22, p < 0.05) levels after adjusting for plasma homocysteine and other potential confounders. Plasma homocysteine displayed no significant correlations with any inflammatory markers. Vitamin B-6 status, rather than homocysteine, appeared to be a significant factor in relation to inflammatory responses for CKD and hemodialysis patients.

Folate and vitamin B-6 status are not associated with homocysteine, oxidative stress and antioxidant capacities in patients with hepatocellular carcinoma.

The purpose of this study was to study the effects of serum folate and plasma pyridoxal 5'-phosphate (PLP) on plasma homocysteine, oxidative stress and antioxidant capacities in 44 hepatocellular carcinoma (HCC) patients and 56 healthy controls. The responses of folate, vitamin B-6, homocysteine, oxidative stress and antioxidant enzyme activities in HCC patients before and after tumor resection were also determined. Patients with HCC before tumor resection had significantly lower folate, PLP, homocysteine, glutathione peroxidase and superoxide dismutase levels, but higher malondialdehyde, total antioxidant capacity and glutathione S-transferase activity when compared with healthy controls. Oxidative stress was significantly decreased to a level similar to that of healthy controls after tumor resection in the HCC group. There were no associations of folate and PLP with plasma homocysteine, indicators of oxidative stress and antioxidant capacities. Serum folate and plasma PLP were not significant factors affecting plasma homocysteine, oxidative stress and antioxidant capacities in patients with HCC.

Evaluation of vitamin B6 intake and status of 20- to 64-year-old Koreans.

BACKGROUND/OBJECTIVESRecent research regarding vitamin B6 status including biochemical index is limited. Thus, this study estimated intakes and major food sources of vitamin B6; determined plasma pyridoxal 5'-phosphate (PLP); and assessed vitamin B6 status of Korean adults.MATERIALS/METHODSThree consecutive 24-h diet recalls and fasting blood samples were collected from healthy 20- to 64-year-old adults (n = 254) living in the Seoul metropolitan area, cities of Kwangju and Gumi, Korea. Vitamin B6 intake and plasma PLP were analyzed by gender and by vitamin B6 supplementation. Pearson's correlation coefficient was used to determine associations of vitamin B6 intake and plasma PLP.RESULTSThe mean dietary and total (dietary plus supplemental) vitamin B6 intake was 1.94 ± 0.64 and 2.41 ± 1.45 mg/day, respectively. Median (50th percentile) dietary intake of men and women was 2.062 and 1.706 mg/day. Foods from plant sources provided 70.61% of dietary vitamin B6 intake. Only 6.3% of subjects consumed total vitamin B6 less than Estimated Average Requirements. Plasma PLP concentration of all subjects was 40.03 ± 23.71 nmol/L. The concentration of users of vitamin B6 supplements was significantly higher than that of nonusers (P < 0.001). Approximately 16% of Korean adults had PLP levels < 20 nmol/L, indicating a biochemical deficiency of vitamin B6, while 19.7% had marginal vitamin B6 status. Plasma PLP concentration showed positive correlation with total vitamin B6 intake (r = 0.40984, P < 0.0001).CONCLUSIONSIn this study, vitamin B6 intake of Korean adults was generally adequate. However, one-third of subjects had vitamin B6 deficiency or marginal status. Therefore, in some adults in Korea, consumption of vitamin B6-rich food sources should be encouraged.

Anthranilic acid and 3‐hydroxyanthranilic acid, but not kynurenic acid, are associated with plasma pyridoxal‐5 phosphate levels

Both high inflammation and low pyridoxal 5′‐phosphate (PLP) status are associated with chronic diseases such as cardiovascular disease and diabetes. A hallmark of inflammation is the induction of indoleamine‐2,3‐dioxygenase (IDO) by the inflammatory cytokine interferon‐γ, leading to the degradation of tryptophan through the kynurenine pathway. Since PLP is a cofactor for many of the enzymes in the kynurenine pathway, we hypothesize that plasma PLP levels could modulate the formation of some of the kynurenines that require PLP as a cofactor for synthesis. To test this, a secondary data analysis was performed on metabolomics data from 1,868 subjects from Framingham Offspring cohort, Exam 5. Using generalized linear models, anthranilic acid (AA) and 3‐hydroxyanthranilic acid (OH‐AA) were found to be positively associated with PLP after adjusting for age, sex, BMI, creatinine, smoking status, and NSAID use (p=0.04 and 0.02, respectively). A 10 nmol/L increase in PLP status was associated with 0.5% and 1.1% increases in AA and OH‐AA, respectively. Kynurenic acid (KA) was not found to be associated with PLP (p = 0.41). Results suggest that AA and OHAA are weakly associated with plasma PLP. Supported by USDA cooperative agreement 51520–008‐045 and NHLBI Framingham Heart Study (Contract No.N01‐HC‐25195).Grant Funding Source: USDA cooperative agreement 51520–008‐045 and NHLBI Framingham Heart Study (Contract No.N01‐HC‐25195).

Prediagnostic plasma vitamin B6 (pyridoxal 5'-phosphate) and survival in patients with colorectal cancer.

Higher plasma pyridoxal 5'-phosphate (PLP) levels are associated with a decreased incidence of colorectal cancer, but the influence of plasma PLP on survival of patients with colorectal cancer is unknown. We prospectively examined whether prediagnostic plasma PLP levels are associated with mortality among colorectal cancer patients. We included 472 incident cases of colorectal cancer identified in the Nurses' Health Study, the Health Professionals Follow-up Study, and the Physicians' Health Study from 1984 to 2002. The patients provided blood samples two or more years before cancer diagnosis. Stratified Cox proportional hazards models were used to calculate hazard ratios (HR) with 95 % confidence intervals (CI) adjusted for other risk factors for cancer survival. Higher plasma PLP levels were not associated with a significant reduction in colorectal cancer-specific (169 deaths) or overall mortality (259 deaths). Compared with patients who had less than 45 pmol/ml of plasma PLP (median: 33.6 pmol/ml), those who had 110 pmol/ml or higher levels (median: 158.8 pmol/ml) had multivariable HRs of 0.85 (95 % CI 0.50-1.45, p trend = 0.37) and 0.87 (95 % CI 0.56-1.35, p trend = 0.24) for colorectal cancer-specific and overall mortality. Higher plasma PLP levels, however, seemed to be associated with better survival among patients who had lower circulating 25-hydroxyvitamin D3 levels (<26.5 ng/ml) (p interaction ≤.005). Higher prediagnostic plasma PLP levels were not associated with an improvement on colorectal cancer survival overall. Further research is needed to clarify the influence of vitamin B6 on colorectal cancer progression and survival.

Folic acid and vitamin B6 deficiencies related hyperhomocysteinemia in apparently healthy Pakistani adults; is mass micronutrient supplementation indicated in this population?

To determine the plasma/serum levels of homocysteine, and vitamins folate, B6 and B12, in Pakistani healthy adults. Cross-sectional study. The Aga Khan University, from October 2006 to April 2008. Fasting levels of plasma/serum folic acid, pyridoxal phosphate (PLP), vitamin B12 and homocysteine were determined in 290 apparently healthy hospital personnel from institutions in two cities of Pakistan. Spearman correlation test and linear regression analysis was conducted. There were 219 males and 71 females with mean age of 46+/-10.5 years and mean body mass index of 23.5 +/-3.8. Mean plasma homocysteine levels in Pakistani normal adults were found to be 17.95+/-8.4 micromol/l. Mean concentrations of plasma/serum folate, vitamin B12 and PLP were found to be 5+/-3.9 ng/ml, 522+/-296 pg/ml and 21.6+/-14 nmol/l, respectively. Serum/plasma levels of folate, vitamin B12 and PLP were negatively correlated with plasma homocysteine (rho coefficient=-0.367, p<0.001; -0.173, p=0.004; -0.185, p=0.002, respectively). Serum folate and plasma PLP levels were inversely related with plasma homocysteine, adjusted for gender, age, smoking and body mass index (p<0.001 and p=0.003, respectively). Percent deficiency values of folate, vitamin B6 and vitamin B12 were 39.7%, 52.8% and 6.6% respectively. The high levels of plasma homocysteine could indicate a reason for mass micronutrient supplementation to prevent the high incidence of cardiovascular disease observed in Pakistani population.

Vitamin B-6 Vitamer Levels in Plasma and Related Symptoms in Hemodialysis Subjects Taking low- and High-Dose Renal Multivitamin Supplements

The purpose of this study was to evaluate the B-6 vitamers in plasma and related symptoms in hemodialysis subjects taking high- or low-dose vitamins. A total of 24 hemodialysis (HD) subjects were divided into two groups. Twelve subjects received a high-dose vitamin supplement [50 mg pyridoxine hydrochloride (PN-HCl) /tablet] and 12 received a low-dose vitamin supplements containing (10 mg PN-HCl/tablet) for 6+ months. Plasma B-6 vitamers were analyzed using HPLC. Other data were obtained from subjects' medical records. Subjects were assessed for vitamin B-6 related symptoms. Cluster analysis was used to form symptom groups. Student t-tests and analysis of variance were used to determine differences (p < 0.05) in group means. The mean ± SD plasma B-6 vitamer and 4-pyridoxic acid concentrations (nmol/L) were as follows in the 10-mg and 50-mg PN-HCl groups, respectively: pyridoxal- 5'-phosphate (PLP) 10 ± 3 and 16 ± 8 (p = 0.04); pyridoxal (PL) 50 ± 96 and 68 ± 06; pyridoxine (PN) 26 ± 50 and 191 ± 107; and 4-pyridoxic acid (4-PA) 43 ± 64 and 99 ± 361. The cluster group with a significantly higher (p = 0.04) plasma 4-PA concentration of 167 ± 697 nmol/L reported more tingling hands, tachycardia, and diarrhea. Plasma PLP levels and symptoms related to B-6 in HD subjects are impacted by dose of PN-HCl.

Vitamin B6 status of 20–59 y old adults in South Korea

To determine dietary vitamin B6 intakes and plasma pyridoxal 5‐ phosphate (PLP) concentrations and to evaluate vitamin B6 status of Korean adults, three consecutive 24‐h food recalls and fasting blood samples were collected from healthy 20–59 y old adults (n=105) living in Seoul and Gyeonggi areas, South Korea. The mean intake of vitamin B6 was 2.06 mg/day. The average ratio of vitamin B6 intake to daily protein intake was 0.027 mg/g protein. Only 4.8% of subjects consumed less than Korean Estimated Average Requirements and 6.2% consumed less than Recommended Nutrient intakes for vitamin B6. None of the subjects consumed vitamin B6 over Tolerable Upper Intake Level for Koreans. The mean plasma PLP level (mean/SD) was 24.6/14.2 nmol/L. There was no significant correlation in vitamin B6 intakes and plasma PLP concentrations (P&gt;=0.05). Approximately 49% of subjects had plasma PLP concentrations &lt;20 nmol/L, which is indicative of vitamin B6 inadequacy status. In conclusion, although vitamin B6 intakes of the subjects were generally adequate, a half of these Korean adults had inadequate vitamin B6 status. Supported by 2011 research fund of National Research Foundation of Korea (2011‐0003749).

Plasma Pyridoxal 5′-Phosphate Is Not Associated with Inflammatory and Immune Responses after Adjusting for Serum Albumin in Patients with Rheumatoid Arthritis: A Preliminary Study

Background/Aims: Plasma pyridoxal 5′-phosphate (PLP) has been shown to be associated with inflammatory and immune responses.Rheumatoid arthritis (RA) is an autoimmune and chronic systemic inflammatory disease and patients with RA have lower plasma PLP levels. We studied the relationship between plasma PLP and inflammatory or immune responses in patients with RA. Methods: This study was designed as an observational cross-sectional study. Forty-three patients with RA were allocated to the adequate (PLP ≥20 nmol/l) (n = 30) or deficient vitamin B₆ (PLP <20 nmol/l) (n = 13) group according to their fasting plasma PLP concentration on the day blood was taken. Plasma PLP, inflammatory parameters [i.e. high-sensitivity CRP (hs-CRP), erythrocyte sedimentation rate, interleukin-6, tumor necrosis factor-α] and immune parameters (i.e. white blood cells, total lymphocytes, neutrophils, T lymphocytes, B lymphocytes, T helper cells and T suppressor cells) were measured. Results: Patients with deficient plasma PLP concentration were mostly considered to have a systemic inflammatory status (hs-CRP >3 mg/l) and apparently had significantly higher mean hs-CRP levels and immune parameters than patients with adequate plasma PLP concentration. There was no significant association between plasma PLP levels and inflammatory parameters. The significantly inverse correlation of plasma PLP with the numbers of white blood cells, neutrophils, total lymphocytes, T lymphocytes and T helper cells remained after adjusting for serum hemoglobin concentration, but the significant correlation disappeared after serum albumin concentration was also considered. Conclusions: RA patients with deficient plasma PLP concentration had more severe inflammatory and immune responses than patients with adequate plasma PLP concentration. However, there was a lack of association of low plasma PLP concentration with inflammatory and immune parameters after serum albumin concentration was considered in patients with RA.

Assessment of vitamin B6status in Korean patients with newly diagnosed type 2 diabetes

The purpose of this study was to assess vitamin B6 intake and status in Korean patients with newly diagnosed type 2 diabetes. Sixty-four patients with newly diagnosed type 2 diabetes and 8-11% glycated hemoglobin (A1C), along with 28 age-matched non-diabetic subjects, participated. Dietary vitamin B6 intake was estimated by the 24 hour recall method and plasma pyridoxal 5'-phosphate (PLP) was measured. There was a significant difference in daily total calorie intake between the diabetic and non-diabetic groups (1,917 ± 376 vs 2,093 ± 311 kcal). There were no differences in intake of total vitamin B6 (2.51 ± 0.91 vs 2.53 ± 0.81 mg/d) or vitamin B6/1,000 kcal (1.31 ± 0.42 vs 1.20 ± 0.32 mg) between the diabetic and non-diabetic groups, andI intakes of total vitamin B6 were above the Korean RDA in both groups (180.0 ± 57.9 vs 179.0 ± 65.4). There was a higher percentage of diabetic subjects whose plasma PLP concentration was < 30 nmol/L compared to non-diabetic group. Plasma PLP levels tended to be lower in the diabetic subjects than in the non-diabetic subjects, although the difference was not statistically significant due to a large standard deviation (80.0 ± 61.2 nmol/L vs 68.2 ± 38.5 nmol/L). Nevertheless, plasma PLP levels should be monitored in pre-diabetic patients with diabetic risk factors as well as in newly diagnosed diabetic patients for long-term management of diabetes, even though this factor is not a major risk factor that contributes to the development of degenerative complications in certain patients.

Vitamin B6 status improves in overweight/obese women following a hypocaloric diet rich in breakfast cereals, and may help in maintaining fat-free mass

To analyze the changes in vitamin B6 status in women following slightly hypocaloric diets based on the relative increase consumption of foods whose intakes are below those recommended, and to study how these changes influence the proportion of fat-free mass. Intervention study of two slightly hypocaloric diets: diet V (increased consumption of vegetables), or diet C (increased consumption of cereals, especially breakfast cereals). A total of 49 women with a body mass index (BMI) of 25-35 kg/m2. Dietetic, anthropometric and biochemical data were collected at the start of the study and at 2 and 6 weeks. Both the C and V subjects showed a reduction in their energy intake, body weight, BMI and fat mass. Pyridoxine intake increased in both groups and plasma pyridoxal phosphate (PLP) levels increased only with diet C. An association was found between the increase in plasma PLP at 6 weeks and the increase in pyridoxine intake (r=0.451; P<0.01). Multiple regression analysis showed a positive association between the increase in PLP at the end of the study and the increases in the pyridoxine intake, B6 density or B6/protein ratio. At the end of the study, and only in those women whose PLP levels were increased, the higher the increase in PLP level, the higher the increase in fat-free mass percentage (r=0.4426, P<0.05). Interventions aimed at weight control should also try to maintain or improve nutritional status. A diet rich in cereals (especially fortified breakfast cereals) appears to be useful in improving vitamin B6 status. Such an improvement could help maintain fat-free mass during periods of weight loss.

Pyridoxal Plasma Level in Schizophrenic and Schizoaffective Patients With and Without Tardive Dyskinesia

Motor disturbances in vitamin B6-deficient animals were described. Some clinical experiments showed that vitamin B6 may ameliorate different drug-induced movement disorders, including tardive dyskinesia (TD). The aim of this study was to compare plasma pyridoxal-5-phosphate (PLP) levels in schizophrenic patients with and without TD. This study was conducted in the Be'er Sheva Mental Health Center from February 2006 to August 2006. Eighty-nine schizophrenic inpatients (40 have TD, 22 men and 18 women, 20-66 yrs old [mean, 48 yrs] and 49 schizophrenic inpatients, 30 men and 19 women, 21-66 yrs old (mean, 49 yrs), without any symptoms of motor disturbances [the control group]) were enrolled in the study. Measurement of PLP is performed by high-performance liquid chromatography separation in all patients. There was a significant difference in plasma PLP levels between patients with TD and those without TD. The discrepancy between the groups was almost entirely attributable to the PLP levels of male patients: 12.4 +/- 11.4 vs 29.0 +/- 12.9 nM in men (P < 0.001), and 19.7 +/- 14.8 vs 22.0 +/- 13.6 nM in women (P > 0.5). Our results suggest that schizophrenic and schizoaffective male patients with TD have lower PLP plasma levels than non-TD patients.

Plasma pyridoxal 5′-phosphate and high-sensitivity C-reactive protein are independently associated with an increased risk of coronary artery disease

Objective Whether vitamin B6 exerts an independent or a synergic effect in combination with inflammation for the risk of coronary artery disease (CAD) is unclear. The purpose of this study was to investigate whether plasma pyridoxal 5′-phosphate (PLP) is dependent on or independent of the inflammation marker C-reactive protein (CRP) to associate with the risk of CAD. Methods This was a hospital-based case-control. Patients were identified with cardiac catheterization as having at least 70% stenosis of one major coronary artery were assigned to the case group ( n = 184). The control group ( n = 516) was comprised of healthy individuals with normal blood biochemical values. All subjects’ height, weight, blood pressure, plasma PLP, homocysteine, high-sensitivity CRP (hs-CRP), and lipid profiles were measured. Results Plasma PLP concentration was only negatively associated with hs-CRP level in the control group (β = −0.001, P = 0.03) but not in the CAD or pooled groups. The magnitude of the risk of CAD for low plasma PLP (odds ratio [OR] 2.39) and high hs-CRP (OR 3.37) was very similar. Low plasma PLP concentration combined with low hs-CRP level (OR 2.34) and high plasma PLP concentration combined with high hs-CRP level (OR 3.61) were independently associated with risk for CAD. However, the combined presence of low PLP and higher hs-CRP levels enhanced the risk of CAD and the magnitude was substantially greater (OR 4.35). Conclusion Plasma PLP and hs-CRP are independently associated with an increased risk of CAD, the combined presence of low PLP and high hs-CRP enhanced the risk of CAD, and the magnitude was almost double.