Biomedical subjects

Kerry-Ann da Costa

Publications and source records attributed to Kerry-Ann da Costa.

7 recordsLinked to original sources

PubMed2006

Choline deficiency increases lymphocyte apoptosis and DNA damage in humans.

BACKGROUND: Whereas deficiency of the essential nutrient choline is associated with DNA damage and apoptosis in cell and rodent models, it has not been shown in humans. OBJECTIVE: The objective was to ascertain whether lymphocytes from choline-deficient humans had greater DNA damage and apoptosis than did those from choline-sufficient humans. DESIGN: Fifty-one men and women aged 18-70 y were fed a diet containing the recommended adequate intake of choline (control) for 10 d. They then were fed a choline-deficient diet for up to 42 d before repletion with 138-550 mg choline/d. Blood was collected at the end of each phase, and peripheral lymphocytes were isolated. DNA damage and apoptosis were then assessed by activation of caspase-3, terminal deoxynucleotide transferase-mediated dUTP nick end-labeling, and single-cell gel electrophoresis (COMET) assays. RESULTS: All subjects fed the choline-deficient diet had lymphocyte DNA damage, as assessed by COMET assay, twice that found when they were fed the control diet. The subjects who developed organ dysfunction (liver or muscle) when fed the choline-deficient diet had significantly more apoptotic lymphocytes, as assessed by the activated caspase-3 assay, than when fed the control diet. CONCLUSIONS: A choline-deficient diet increased DNA damage in humans. Subjects in whom these diets induced liver or muscle dysfunction also had higher rates of apoptosis in their peripheral lymphocytes than did subjects who did not develop organ dysfunction. Assessment of DNA damage and apoptosis in lymphocytes appears to be a clinically useful measure in humans (such as those receiving parenteral nutrition) in whom choline deficiency is suspected.

Adolescent↗

PubMed2006

Common genetic polymorphisms affect the human requirement for the nutrient choline.

Humans eating diets deficient in the essential nutrient choline can develop organ dysfunction. We hypothesized that common single nucleotide polymorphisms (SNPs) in genes involved in choline metabolism influence the dietary requirement of this nutrient. Fifty-seven humans were fed a low choline diet until they developed organ dysfunction or for up to 42 days. We tested DNA SNPs for allelic association with susceptibility to developing organ dysfunction associated with choline deficiency. We identified an SNP in the promoter region of the phosphatidylethanolamine N-methyltransferase gene (PEMT; -744 G-->C; rs12325817) for which 18 of 23 carriers of the C allele (78%) developed organ dysfunction when fed a low choline diet (odds ratio 25, P=0.002). The first of two SNPs in the coding region of the choline dehydrogenase gene (CHDH; +318 A-->C; rs9001) had a protective effect on susceptibility to choline deficiency, while a second CHDH variant (+432 G-->T; rs12676) was associated with increased susceptibility to choline deficiency. A SNP in the PEMT coding region (+5465 G-->A; rs7946) and a betaine:homocysteine methyltransferase (BHMT) SNP (+742 G-->A; rs3733890) were not associated with susceptibility to choline deficiency. Identification of common polymorphisms that affect dietary requirements for choline could enable us to identify individuals for whom we need to assure adequate dietary choline intake.

Choline↗

PubMed2005

Genetic variation of folate-mediated one-carbon transfer pathway predicts susceptibility to choline deficiency in humans.

Choline is a required nutrient, and some humans deplete quickly when fed a low-choline diet, whereas others do not. Endogenous choline synthesis can spare some of the dietary requirement and requires one-carbon groups derived from folate metabolism. We examined whether major genetic variants of folate metabolism modify susceptibility of humans to choline deficiency. Fifty-four adult men and women were fed diets containing adequate choline and folate, followed by a diet containing almost no choline, with or without added folate, until they were clinically judged to be choline-deficient, or for up to 42 days. Criteria for clinical choline deficiency were a more than five times increase in serum creatine kinase activity or a >28% increase of liver fat after consuming the low-choline diet that resolved when choline was returned to the diet. Choline deficiency was observed in more than half of the participants, usually within less than a month. Individuals who were carriers of the very common 5,10-methylenetetrahydrofolate dehydrogenase-1958A gene allele were more likely than noncarriers to develop signs of choline deficiency (odds ratio, 7.0; 95% confidence interval, 2.0-25; P < 0.01) on the low-choline diet unless they were also treated with a folic acid supplement. The effects of the C677T and A1298C polymorphisms of the 5,10-methylene tetrahydrofolate reductase gene and the A80C polymorphism of the reduced folate carrier 1 gene were not statistically significant. The most remarkable finding was the strong association in premenopausal women of the 5,10-methylenetetrahydrofolate dehydrogenase-1958A gene allele polymorphism with 15 times increased susceptibility to developing organ dysfunction on a low-choline diet.

Adult↗

PubMed2005

Choline deficiency in mice and humans is associated with increased plasma homocysteine concentration after a methionine load.

BACKGROUND: Elevated concentrations of homocysteine in blood may be an independent risk factor for the development of atherosclerosis. Elevated homocysteine concentrations can be caused by decreased methylation of homocysteine to form methionine, as occurs in folate deficiency. A parallel pathway exists for methylation of homocysteine, in which choline, by way of betaine, is the methyl donor. OBJECTIVE: Our goal was to determine whether choline deficiency results in a decreased capacity to methylate homocysteine. DESIGN: C57BL/6J mice were fed diets containing 0, 10, or 35 mmol choline/kg diet for 3 wk. We then administered an oral methionine load to the animals and measured plasma homocysteine concentrations. Also, in a pilot study, we examined 8 men who were fed a diet providing 550 mg choline/d per 70 kg body weight for 10 d, followed by a diet providing almost no choline, until the subjects were clinically judged to be choline deficient or for <or=42 d. A methionine load was administered at the end of each dietary phase. RESULTS: Two hours after the methionine load, choline-deficient mice had plasma homocysteine concentrations twice those of choline-fed mice. Four hours after the methionine load, clinically choline-depleted men had plasma homocysteine concentrations that were 35% greater than those in men not choline depleted. CONCLUSION: These results suggest that choline, like folate, plays an important role in the metabolism of homocysteine in humans and that response to a methionine load may be useful when assessing choline nutriture.

Adult↗

PubMed2005

Regulation of choline deficiency apoptosis by epidermal growth factor in CWSV-1 rat hepatocytes.

Previous studies show that acute choline deficiency (CD) triggers apoptosis in cultured rat hepatocytes (CWSV-1 cells). We demonstrate that prolonged EGF stimulation (10 ng/mL x 48 hrs) restores cell proliferation, as assessed by BrdU labeling, and protects cells from CD-induced apoptosis, as assessed by TUNEL labeling and cleavage of poly(ADP-ribose) polymerase. However, EGF rescue was not accompanied by restoration of depleted intracellular concentrations of choline, glycerphosphocholine, phosphocholine, or phosphatidylcholine. In contrast, we show that EGF stimulation blocks apoptosis by restoring mitochondrial membrane potential (Delta Psi(m)), as determined using the potential-sensitive dye chloromethyl-X-rosamine, and by preventing the release and nuclear localization of cytochrome c. We investigated whether EGF rescue involves EGF receptor phosphorylation and activation of the down-stream cell survival factor Akt. Compared to cells in control medium (CT, 70 micromol choline x 48 hrs), cells in CD medium (5 micromol choline) were less sensitive to EGF-induced (0-300 ng/mL x 5 min) receptor tyrosine phosphorylation. Compared to cells in CT medium, cells in CD medium treated with EGF (10 ng/mL x 5 min) exhibited higher levels of phosphatidylinositol 3-kinase (PI3K)-dependent phosphorylation of AktSer473. Inactivation of PI3K was sufficient to block EGF-stimulated activation of Akt, restoration of mitochondrial Delta Psi(m), and prevention of cytochrome c release. These studies indicate that stimulation with EGF activates a cell survival response against CD-apoptosis by restoring mitochondrial membrane potential and preventing cytochrome c release and nuclear translocation which are mediated by activation of Akt in hepatocytes.

Animals↗

PubMed2004

Choline- and betaine-defined diets for use in clinical research and for the management of trimethylaminuria.

This article describes the development of a series of choline- and betaine-controlled diets that were served to research subjects as part of an ongoing study of diet requirements in humans. These diets were developed based on the analysis of choline and betaine in individual foods. The calculated diets were compared with analyses of all foods combined into a single sample for each day. The laboratory analyses of choline and betaine in the whole-diet aliquots matched the estimated amounts in the diets that were calculated from the analyses of individual foods. These diets were adjusted for several levels of choline and betaine and were well accepted by research subjects who consumed them for a time period of up to 2 months. This article describes applications of this diet for use in clinical research on methyl-group requirements in humans and for use in clinical practice for counseling the client who requires a choline-controlled diet.

Betaine↗

PubMed2004

Elevated serum creatine phosphokinase in choline-deficient humans: mechanistic studies in C2C12 mouse myoblasts.

BACKGROUND: Choline is a required nutrient, and humans deprived of choline develop liver damage. OBJECTIVE: This study examined the effect of choline deficiency on muscle cells and the release of creatine phosphokinase (CPK) as a sequela of that deficiency. DESIGN: Four men were fed diets containing adequate and deficient amounts of choline, and serum was collected at intervals for measurement of CPK. C2C12 mouse myoblasts were cultured in a defined medium containing 0 or 70 micromol choline/L for up to 96 h, and CPK was measured in the media; choline and metabolites were measured in cells. Apoptosis was assessed by using terminal deoxynucleotidyl transferase-mediated dUTP-biotin end labeling and activated caspase-3 immunohistochemistry. Cell fragility in response to hypo-osmotic stress was also assessed. RESULTS: Three of 4 humans fed a choline-deficient diet had significantly elevated serum CPK activity derived from skeletal muscle (up to 66-fold; P < 0.01) that resolved when choline was restored to their diets. Cells grown in choline-deficient medium for 72 h leaked 3.5-fold more CPK than did cells grown in medium with 70 micromol choline/L (control medium; P < 0.01). Apoptosis was induced in cells grown in choline-deficient medium. Phosphatidylcholine concentrations were diminished in choline-deficient cells (to 43% of concentrations in control cells at 72 h; P < 0.01), as were concentrations of intracellular choline, phosphocholine, and glycerophosphocholine. Cells grown in choline-deficient medium had greater membrane osmotic fragility than did cells grown in control medium. CONCLUSIONS: Choline deficiency results in diminished concentrations of membrane phosphatidylcholine in myocytes, which makes them more fragile and results in increased leakage of CPK from cells. Serum CPK may be a useful clinical marker for choline deficiency in humans.

Adult↗