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Disorders of vitamin B6 metabolism
Published in William L. Nyhan, Georg F. Hoffmann, Aida I. Al-Aqeel, Bruce A. Barshop, Atlas of Inherited Metabolic Diseases, 2020
α-AASA is elevated in blood, urine, and cerebrospinal fluid (CSF) [19, 23]. Concentrations in plasma have ranged from 0.9–8.0 μmol/L and in urine from 4 to 75 mmol/mol creatinine [23]. The availability of this biomarker for the disease has made clinical testing for pyridoxine responsiveness obsolete, however empirical treatment with pyridoxine should not be withheld until diagnostic samples are collected. This concept is particularly useful for it makes the withdrawal of treatment unnecessary to pursue testing. Pipecolic acid is also elevated in plasma and CSF, but this may be only modestly elevated, and this is a less reliable biomarker. Pipecolic acid is also elevated in other inborn errors of metabolism such as disorders of peroxisomal biogenesis, and hyperlysinemia. Urinary levels of pipecolic acid are often normal [23]. Levels of piperideine-6-carboxylate are also elevated; this compound is in equilibrium with α-AASA (Figure 100.2) in the pathway for the catabolism of lysine. α-AASA is also elevated in molybdenum cofactor deficiency [24], another cause of severe neonatal seizures. Levels of excretion range from 9.6–16.9 mmol/mol creatinine, certainly within range of antiquitin deficiency. Hypouricemia or elevated excretion of xanthine, sulfite or sulfocysteine in molybdenum cofactor deficiency should elucidate the differential diagnosis.
Mitochondrial and peroxisomal disorders
Published in Steve Hannigan, Inherited Metabolic Diseases: A Guide to 100 Conditions, 2018
The diagnosis of Zellweger syndrome is usually suspected clinically. The urine may show excess pipecolic acid, and medium- and long-chain dicarboxylic acids. The diagnosis of this disorder may be conirmed by establishing abnormalities in more than one peroxisomal function. Speciic biochemical tests include very-long-chain fatty acids (VLCFAs), dihydroxyacetone phosphate acyltransferase activity, phyta-nate/pristanate levels and plasmalogens. Morphological studies of liver and/or skin for ibroblasts may show a complete absence of or reduced or abnormal structure of peroxisomes. The diagnosis is conirmed by speciic enzyme analysis of skin ibro-blasts.
Nutritional Ergogenic Aids: Introduction, Definitions and Regulatory Issues
Published in Ira Wolinsky, Judy A. Driskell, Nutritional Ergogenic Aids, 2004
Ira Wolinsky, Judy A. Driskell
In our attempt to identify a potential mechanism of action we looked at the major pathways of lysine metabolism. One pathway converts the amino acid to alpha-aminoadipate via pipecolic acid.66 This is considered an overflow pathway of lysine metabolism and is especially active in the brain. This could possibly link high lysine intake to GH release, since pipecolate is thought to act as an agonist for the gamma-aminobutyric acid (GABA) receptor.6”8 GABA in turn has been shown to influence the release of GH from the pituitary.69-72 Therefore, if pipecolic acid levels are increased from lysine metabolism, enhanced GABA receptor activity could potentially increase GH secretion.
Depression and anxiety in patients with active ulcerative colitis: crosstalk of gut microbiota, metabolomics and proteomics
Published in Gut Microbes, 2021
Xiaomin Yuan, Biqing Chen, Zhenglan Duan, Ziqian Xia, Yang Ding, Tuo Chen, Huize Liu, Baosheng Wang, Bolin Yang, Xiaoyong Wang, Shijia Liu, Jin-Yong Zhou, Yajun Liu, Qiong Wang, Zhaofeng Shen, Jun Xiao, Hongtao Shang, Weiwei Liu, Guoping Shi, Lei Zhu, Yugen Chen
Meanwhile, 2ʹ-deoxy-D-ribose is a DNA backbone, and it could be consumed and synthesized by various gut bacteria.37–39 It plays a role in resisting apoptosis and in regulating the host’s immune response.40–42 However, its function in the nervous system is still unclear. Since it was significantly decreased in UCD/UCA, and its supplementation in mice could significantly mitigate their DSS-induced depressive-like behaviors, it is worthwhile to investigate the molecular mechanism of 2ʹ-deoxy-D-ribose in UCD/UCA. Another metabolite that decreased in UCD/CUA is L-pipecolic acid, which is an intermediate metabolite of L-lysine in the brain, and it could activate GABA receptors.43,44 Both GABA and L-pipecolic acid were reduced in the blood of mice with colitis and depressive-like behaviors, which could be alleviated by L-pipecolic acid supplementation. Major depression and anxiety disorders share a GABAergic deficit as a common pathophysiology, L-pipecolic acid can potentially relieve depression and anxiety via the GABAergic system.45 The intervention of 2ʹ-deoxy-D-ribose and L-pipecolic acid in DSS-treated mice restored the serum IGHV3 and IGKV3 levels, respectively, and decreased the pro-inflammatory cytokines systematically (in the blood) and locally (in the hippocampus). As the serum levels of these two metabolites were significantly correlated with the serum levels of the two immunoglobulins in patients with UC, the two beneficial metabolites possibly have a potential role in the host immune response of patients with UC and depression/anxiety.