Dietary Pyridoxine Deficiency Research Articles

The regulatory effects of pyridoxine deficiency on the grass carp (Ctenopharyngodon idella) gill barriers immunity, apoptosis, antioxidant, and tight junction challenged with Flavobacterium columnar

The effects of dietary pyridoxine (PN) on the gill immunity, apoptosis, antioxidant and tight junction of grass cap (Ctenopharyngodon idella) were investigated in this study. Fish were fed semi-purified diets containing graded levels of PN for 10 weeks, and then challenged with Flavobacterium columnare by bath immersion exposure for 3 days. The results indicated that compared with the optimal PN level, PN deficiency resulted in a decline in the antimicrobial compound production of gill. In addition, PN deficiency up-regulated the pro-inflammatory cytokines and down-regulated the anti-inflammatory cytokines gene expression, which might be associated with the enhanced nuclear factor κB p65 and the inhibited target of rapamycin signalling pathways, respectively, suggesting that PN deficiency could impair gill immune barrier function. Furthermore, PN deficiency (1) induced cell apoptosis, which may be partly associated with the (apoptotic protease activating factor-1, Bcl-2 associated X protein)/caspase-9 and c-Rel/tumor necrosis factor α (rather than FasL)/caspase-8 mediated apoptosis pathway. (2) Inhibited Kelch-like ECH-associating protein 1a/NF-E2-related factor 2 mRNA expression, decreased the mRNA expression and activities of antioxidant enzymes, increased the levels of reactive oxygen species, protein carbonyl and malondialdehyde. (3) Increased the mRNA expression level of myosin light chain kinase, which may be result in the down-regulation of tight junction complexes such as zonula occludens 1, occludin and claudins (expect claudin-12 and claudin-15). These results suggest that PN deficiency could impair gill physical barrier function. In summary, dietary PN deficiency could cause the impairment of gill barrier function associated with immunity, apoptosis, antioxidant and tight junction, which may result in the increased the susceptibility of fish to pathogenic bacteria. Moreover, based on the gill rot morbidity, LZ activity and MDA content, the dietary PN requirements for grass cap were estimated to be 4.85, 4.78 and 4.77 mg kg−1 diet, respectively.

Dietary pyridoxine deficiency reduced growth performance and impaired intestinal immune function associated with TOR and NF-κB signalling of young grass carp (Ctenopharyngodon idella)

The objective of this study was to evaluate the effects of dietary pyridoxine (PN) deficiency on growth performance, intestinal immune function and the potential regulation mechanisms in young grass carp (Ctenopharyngodon idella). Fish were fed six diets containing graded levels of PN (0.12–7.48 mg/kg) for 70 days. After that, a challenge test was conducted by infection of Aeromonas hydrophila for 14 days. The results showed that compared with the optimal PN level, PN deficiency: (1) reduced the production of innate immune components such as lysozyme (LZ), acid phosphatase (ACP), complements and antimicrobial peptides and adaptive immune components such as immunoglobulins in three intestinal segments of young grass carp (P < 0.05); (2) down-regulated the mRNA levels of anti-inflammatory cytokines such as transforming growth factor β (TGF-β), interleukin 4/13A (IL-4/13A) (rather than IL-4/13B), IL-10 and IL-11 partly relating to target of rapamycin (TOR) signalling [TOR/ribosomal protein S6 kinases 1 (S6K1) and eIF4E-binding proteins (4E-BP)] in three intestinal segments of young grass carp; (3) up-regulated the mRNA levels of pro-inflammatory cytokines such as tumour necrosis factor α (TNF-α) [not in the proximal intestine (PI) and distal intestine (DI)], IL-1β, IL-6, IL-8, IL-12p35, IL-12p40, IL-15 and IL-17D [(rather than interferon γ2 (IFN-γ2)] partly relating to nuclear factor kappa B (NF-κB) signalling [IκB kinase β (IKKβ) and IKKγ/inhibitor of κBα (IκBα)/NF-κB (p65 and c-Rel)] in three intestinal segments of young grass carp. These results suggest that PN deficiency could impair the intestinal immune function, and the potential regulation mechanisms were partly associated with TOR and NF-κB signalling pathways. In addition, based on percent weight gain (PWG), the ability against enteritis and LZ activity, the dietary PN requirements for young grass carp were estimated to be 4.43, 4.75 and 5.07 mg/kg diet, respectively.

Hlf is a genetic modifier of epilepsy caused by voltage-gated sodium channel mutations

Mutations in voltage-gated sodium channel genes cause several types of human epilepsies. Often, individuals with the same sodium channel mutation exhibit diverse phenotypes. This suggests that factors beyond the primary mutation influence disease severity, including genetic modifiers. Mouse epilepsy models with voltage-gated sodium channel mutations exhibit strain-dependent phenotype variability, supporting a contribution of genetic modifiers in epilepsy. The Scn2aQ54 (Q54) mouse model has a strain-dependent epilepsy phenotype. Q54 mice on the C57BL/6J (B6) strain exhibit delayed seizure onset and improved survival compared to [B6xSJL/J]F1.Q54 mice. We previously mapped two dominant modifier loci that influence Q54 seizure susceptibility and identified Hlf (hepatic leukemia factor) as a candidate modifier gene at one locus. Hlf and other PAR bZIP transcription factors had previously been associated with spontaneous seizures in mice thought to be caused by down-regulation of the pyridoxine pathway. An Hlf targeted knockout mouse model was used to evaluate the effect of Hlf deletion on Q54 phenotype severity. HlfKO/KO;Q54 double mutant mice exhibited elevated frequency and reduced survival compared to Q54 controls. To determine if direct modulation of the pyridoxine pathway could alter the Q54 phenotype, mice were maintained on a pyridoxine-deficient diet for 6 weeks. Dietary pyridoxine deficiency resulted in elevated seizure frequency and decreased survival in Q54 mice compared to control diet. To determine if Hlf could modify other epilepsies, HlfKO/+ mice were crossed with the Scn1aKO/+ Dravet syndrome mouse model to examine the effect on premature lethality. HlfKO/+;Scn1aKO/+ offspring exhibited decreased survival compared to Scn1aKO/+ controls. Together these results demonstrate that Hlf is a genetic modifier of epilepsy caused by voltage-gated sodium channel mutations and that modulation of the pyridoxine pathway can also influence phenotype severity.

Impact of pyridoxine (B6) deficiency on serine kinetics in the pig

The water‐soluble vitamin B6 serves a cofactor for serine hydroxymethyltransferase (SHMT), an enzyme critical to cellular one carbon flow. The current experiment was designed to test the alternate hypothesis that B6 deficiency in an animal model will reduce SHMT activity and serine flux, as measured by stable isotopic dilution protocols. Pigs (commercial genotype; initial wt = 4.7 kg; n=6/treatment) were offered a basal semi‐purified diet (20.5% casein; 3474 kcal ME/kg) containing either 0 (B6−) or 3 (B6+) mg/kg pyridoxine·HCl for a 3 week feeding period, using a pair‐feeding design. At the end of the depletion period, a 6 hr primed (90 μmole/kg)‐constant (90 μmole/kg/h) infusion of L‐[2,3,3‐2H3] serine was administered via indwelling jugular vein catheter. Blood samples (femoral vein catheter) were collected at −60, 0, 60, 120, 180, 240, 300 and 360 min. Tissues were harvested at termination and samples processed for plasma serine m+3 enrichment (GC‐MS), plasma pyridoxal‐5‐phosphate (PLP; radioimmunoassay), and liver SHMT activity. Different superscripts indicate significant differences (P&lt;0.05) by ANOVA F‐test.The current data allow us to accept the alternate hypothesis of a reduction in SHMT activity induced by dietary pyridoxine deficiency, with a concomitant reduction in serine flux. This reduction in serine flux may have implications for overall one‐carbon metabolism, including pathways linked to folate and sulfur amino acid metabolism. Support: Natural Sciences and Engineering Research Council of Canada (NSERC)

Effects of pyridoxine deficiency on the metabolism of N-nitrosodimethylamine in the rat.

The alteration in the metabolic activation of N-nitrosodimethylamine (NDMA) was investigated in the rat during dietary pyridoxine deficiency. The in vitro metabolism of NDMA by demethylase system was measured in both liver and kidney microsomes. The profile of the kidney enzyme appears similar to that of the liver indicating that at least two forms of isozymes with the low and the high Km's are present. Pyridoxine deficiency significantly increased the activity of NDMA-demethylase of both organs. The increase in the activity of NDMA-demethylase induced by dietary pyridoxine deficiency can be reversed by supplementation of pyridoxine (500 micrograms), i.p., daily for two consecutive days. The increase in the NADPH cytochrome c reductase activity was observed after 6 weeks on pyridoxine-deficient diet.

Seizure activity in pyridoxine-deficient adult rats.

This investigation tested the hypothesis that the degree of pyridoxine depletion rather than the status of neuronal maturity determines seizure proneness in the pyridoxine-deficient rat. Dietary pyridoxine deficiency was induced in neuronally mature rats. Seizure activity was monitored using computerized EEG analysis. Dietary pyridoxine deficiency of 10 weeks' duration induced in neuronally mature rats led to spontaneous convulsive seizure activity. Even moderately pyridoxine-deficient adult rats (on the deficient diet for less than 8 weeks) exhibited seizure-like diffuse spike and wave activity and electrocortical inhibition. Picrotoxin-, pentylenetetrazol-, or domoic acid-induced seizure thresholds were significantly reduced in pyridoxine-deficient rats when compared with normal controls. Pyridoxine-deficient rats exhibited increased dominance of delta and theta activities and increased hemispherical asymmetries in response to convulsant treatment.

Effect of dietary pyridoxine deficiency on intestinal functions in rats

Dietary pyridoxine deficiency in rats significantly reduced (20–43%) the intestinal uptake of D-glucose, glycine, L-alanine and L-leucine. An appreciable reduction in the activities of sucrase, lactase, alkaline phosphatase and leucine amino peptidase was also observed, but maltase activity was unaffected under these conditions. A con-siderable decrease (27–66%) in membrane proteins, sialic acid, phospholipids and free cholesterol fractions in vitamin deficiency was observed. Estercholesterol and triglyceride contents were not affected. Acetate-1- 14C incorporation into various lipid fractions indicated that observed decrease in membrane lipids in B6 deficiency was a consequence of reduced synthesis. It is concluded that pyridoxine deprivation produces marked changes in chemical architecture of brush borders, which probably explains the observed aberrations in epithelial cell function in this nutritional deficiency.

Pathology of vitamin B‐6 deficiency in Channa (=Ophiocephalus) punctatus Bloch

Abstract. Pyridoxine deficiency was experimentally produced in a population of Channa punctatus Bloch by feeding a pyridoxine deficient vitamin test diet for 240 days. The deficiency effects were further accentuated in another group of fish by adding 4‐deoxypyridoxine as an antagonist to the deficient diet. The behaviour, general morphology and growth of these fish were compared with control fish maintained on a complete vitamin test diet. The behavioural study revealed a series of nervous disorders such as ataxia, hyperirritability and muscular spasm followed by convulsions, fits, anorexia and paralysis in the posterior region during advanced stages of the deficiency. Gross morphological changes recorded were retarded growth and loss of weight resulting in a pinhead condition; integumentary damage such as scale loss, leakage of oedematous fluid and abnormal pigmentation, opacity of the lens resulting in complete blindness and enlargement and nodule formation in the spleen and kidney. Recovery treatment for 30 days comprising restoration of dietary supply of pyridoxine supplemented by intramuscular injections brought about considerable recovery in the fish with dietary pyridoxine deficiency but the antagonist‐treated deficient group showed little recovery, although further deterioration was halted.

Regional distribution of pyridoxal-5?-phosphate in developing and mature brains and its depletion in pyridoxine deficiency

A study was made of (a) the distribution of the coenzyme pyridoxal-5'-phosphate (PLP) in four discrete regions of developing and mature rat brains and (b) the effect of dietary pyridoxine deficiency on the distribution. There was an increase in PLP concentration of all the regions from infancy to adulthood. Highest concentration of PLP was found in the medulla and pons in both infants and adults. Pyridoxine deficiency resulted in a more marked reduction of PLP in all regions of the neonatal brain as compared with those in the mature brain. This is consistent with the vulnerability of the developing brain to nutritional stresses.

Effect of postweanling pyridoxine deficiency on growth and concentration of the coenzyme pyridoxal-5'-phosphate in heart, kidneys, lungs, and adrenals in rats.

Dietary pyridoxine deficiency induced in postweanling rats to led to severe growth retardation and growth failure, with a sharp increase in the mortality rate after about 8 weeks on the diet. The absolute weights of heart, lungs, kidneys, and adrenals were all lower in the deficient animals than those of the controls. However, when the weights were expressed in terms of percentage of body weight, a 2-fold increase was observed indicative of marked hypertrophy. The depletion of the coenzyme pyridoxal-5'-phosphate from these tissues was extensive (heart 48%, lungs 85%, and kidneys and adrenals 88%.) The extent of loss of the coenzyme from the tissues suggests possible functional changes.

Electroencephalographic study of l-glutamate induced seizures in rats

The ip administration of l-glutamate was found to induce clonic movements and tonic-clonic seizures in rats at a dose level of 2.0 mmole/100 g body weight. The susceptibility to the seizures was not affected by dietary pyridoxine deficiency. The seizure episodes were characterized by 3–5 cps high amplitude spikes ranging from 200 μV/cm to 1000 μV/cm. In the interseizure periods records showed 1 cps high voltage slow waves. The results are discussed in terms of possible biochemical mechanisms operative in the glutamate induced seizures.

Effect of dietary pyridoxine deficiency on experimental porphyria

Severe pyridoxine deficiency did not impair the induction of hepatic δ-amino-levulinic acid synthetase (ALAS) produced by allylisopropylacetamide in rats. The enzyme, when induced to levels six times normal, was fully saturated by cofactor (pyridoxal phosphate) in pyridoxine deficient rats. The depletion of plasma pyridoxal phosphate was similar in starved animals with normal levels of hepatic ALAS and starved animals with high levels of hepatic ALAS induced for 10 days by allylisopropylacetamide.

Effects of steroid and nonsteroid metabolites on enzyme conformation and pyridoxal phosphate binding.

Studies on the effects of steroid and nonsteroid metabolites on enzy me conformation and pyridoxal phosphate binding were reviewed. The results indicate that conjugated steroids can cooperate with or oppose the actions of specific nonsteroid effectors in determining enzyme conformation activity stability and coenzyme binding. Evidence is presented that these actions of steroid and nonsteroid metabolites can cause a redistribution of pyridoxal phosphate between apoenzymes. It was considered that similar actions may account for the ability of estrogens to cause changes in tryptophan metabolism resembling those occurring during pyridoxine deficiency. Effects of estrogen-treatment and of dietary pyridoxine deficiency on the kynurenine transaminase levels in liver and kidneys of male rats were compared. Pyridoxine deficiency resulted in a moderate decline of the % saturation of the renal supernatant enzyme with pyridoxal phosphate but also caused an apparent decline in apoenzyme levels. Renal mitrochondrial apotransaminase levels decreased slightly during pyridoxine deficiency but were markedly decreased by estrogen treatment. Female rats displayed similar results to those of estrogen-treated males. These results indicate that the estrogens influence kynurenine transaminase in vivo in a way similar to that observed in vitro but also demonstrate that they do not cause the same pattern of change in apoenzyme levels and pyridoxal phosphate distribution as the dietary pyridoxine deficiency.

Nonmast-cell histamine kinetics—II: Effect of histidine decarboxylase inhibitors on rates of decline of tissue 3H-histamine in the female rat

Inhibition of histamine synthesis in vivo was examined in terms of effects on the kinetics of decline of exogenous 3H-histamine in various tissues of the female rat. Inhibition of tissue histidine decarboxylase activity by dietary pyridoxine deficiency coupled with semicarbazide administration greatly reduced rates of decline in vivo of labeled amine. On the assumption that exogenous 3H-histamine equilibrates with endogenous amine in nonmast-cell pools, estimated rates of turnover of loosely bound histamine were reduced 30–75 per cent. The histidine decarboxylase inhibitor, NSD-1055 (4-bromo-3-hydroxybenzyloxyamine) was ineffective in reducing endogenous histamine levels and did not affect the kinetics of decline of 3H-histamine. It is suggested that the kinetics of 3H-histamine in vivo decline and the tissue histidine decarboxylase activity in vitro may reflect the same biochemical phenomenon—presumably the synthesis and catabolism of loosely bound nonmast-cell histamine in dynamic endogenous pools.

Pyridoxine-dependent convulsions in an infant.

The association of dietary pyridoxine deficiency and convulsions was first noted in animal experiments by Chick, El Sadr and Worden (1940). An analogous situation in humans was recognized when Snyderman, Carretero and Holt (1950) described the onset of seizures in a mentally retarded child whose diet lacked this vitamin. Shortly afterwards, an outbreak of convulsions in young infants in the United States was shown to be due to the low pyridoxine content in their diet (Coursin, 1954; Molony, 1954; Bessey, Adam, Bussey and Hansen, 1954; Adam, Bessey, Bussey and Hansen, 1954; May, 1954). An association of a different category was first recorded when Hunt, Stokes, McCrory and Stroud (1954) described the case of an infant who began to suffer from seizures a few hours after birth. Pyridoxine in high doses abolished the attacks, and the term 'pyridoxine dependency' was used to describe this situation in which convulsions are of early onset and dietary deficiency cannot be invoked. Only three other reports have been encountered (Bessey, Adam and Hansen, 1957; Marie, Hennequet, Lyon, Debris and Le Balle, 1959; Scriver, 1960) describing infants whose attacks similarly responded to pyridoxine therapy. The case reported here seems to fulfil the criteria for its acceptance as a further instance of convulsions associated with a state of pyridoxine dependency.