Background: Renal insufficiency is associated with altered vitamin B-6 metabolism. We have observed high concentrations of 4-pyridoxic acid, the major catabolite of vitamin B-6 metabolism, in plasma during renal insufficiency.
Objective: The objective was to evaluate the renal handling of 4-pyridoxic acid and the effects of renal dysfunction on vitamin B-6 metabolism.
Design: We measured the renal clearance of 4-pyridoxic acid and creatinine in 17 nonpregnant, 17 pregnant, and 16 lactating women. We then examined the influence of vitamin B-6 or alkaline phosphatase activity on the ratio of 4-pyridoxic acid to pyridoxal (PA:PL) in plasma in 10 men receiving a low (0.4 mg pyridoxine.HCl/d) or high (200 mg pyridoxine.HCl/d) vitamin B-6 intake for 6 wk, in 10 healthy subjects during a 21-d fast, in 1235 plasma samples from 799 people screened for hypophosphatasia, and in 67 subjects with a range of serum creatinine concentrations.
Results: Renal clearance of 4-pyridoxic acid was 232 +/- 94 mL/min in nonpregnant women, 337 +/- 140 mL/min in pregnant women, and 215 +/- 103 mL/min in lactating healthy women. These values were approximately twice the creatinine clearance, indicating that 4-pyridoxic acid is at least partially eliminated by tubular secretion. Elevated plasma creatinine concentrations were associated with marked elevations in 4-pyridoxic acid and PA:PL. PA:PL was not affected by wide variations in vitamin B-6 intake or by the wide range of pyridoxal-P concentrations encountered while screening for hypophosphatasia.
Conclusions: Plasma 4-pyridoxic acid concentrations are markedly elevated in renal insufficiency. Plasma PA:PL can distinguish between increases in 4-pyridoxic acid concentrations due to increased dietary intake and those due to renal insufficiency.
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http://dx.doi.org/10.1093/ajcn/75.1.57 | DOI Listing |
Gut Microbes
December 2025
Department of Anesthesiology, Third Xiangya Hospital, Central South University, Changsha, Hunan, China.
Chronic stress can result in various conditions, including psychological disorders, neurodegenerative diseases, and accelerated brain aging. Gut dysbiosis potentially contributes to stress-related brain disorders in individuals with chronic stress. However, the causal relationship and key factors between gut dysbiosis and brain disorders in chronic stress remain elusive, particularly under non-sterile conditions.
View Article and Find Full Text PDFNutrients
October 2024
Department of Epidemiology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China.
Background: Studies on the association between serum vitamin B status and colorectal cancer prognosis are limited and have yielded inconsistent results. This study investigated the association of pyridoxal 5'-phosphate (PLP) and pyridoxic acid ratio (PAr) index with colorectal cancer survival.
Methods: A total of 1286 colorectal cancer patients diagnosed since 2010 were selected from the Guangdong Colorectal Cancer Cohort study.
J Occup Environ Med
December 2024
From the Department of Respiratory and Critical Care Medicine, The Third People's Hospital of Hefei, Hefei, Anhui, China (X.Q., X.W., X.C., G.R.); Department of Occupational Health and Environmental Health, School of Public Health, Anhui Medical University, Hefei, Anhui, China (X.Q., Y.L.); Department of Respiratory and Critical Care Medicine, The Third People's Hospital of Hefei, Hefei Third Clinical College of Anhui Medical University, Hefei, Anhui, China (X.Q.); and Department of Science and Education, The Third People's Hospital of Hefei, Hefei Third Clinical College of Anhui Medical University, Hefei, Anhui, China (X.H.).
Clin Transl Gastroenterol
November 2024
Division of Nephrology, Department of Medicine, University of Washington, Seattle, Washington, USA.
Ann Nutr Metab
September 2024
Department of Laboratory Medicine, Peking Union Medical College Hospital, Peking Union Chinese Academy of Medical Sciences, Beijing, China.
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