Variability of plasma and urine betaine in diabetes mellitus and its relationship to methionine load test responses: an observational study

BACKGROUND: Since betaine is an osmolyte and methyl donor, and abnormal betaine loss is common in diabetes mellitus (>20% patients), we investigated the relationship between betaine and the post-methionine load rise in homocysteine, in diabetes and control subjects. The post-methionine load test is reported to be both an independent vascular risk factor and a measure of betaine sufficiency.
METHODS: Patients with type 2 diabetes (n = 34) and control subjects (n = 17) were recruited. We measured baseline fasting plasma and 4-hour post-methionine load (L-methionine, 0.1 mg/kg body weight) concentrations of homocysteine, betaine, and the betaine metabolite N,N-dimethylglycine. Baseline urine excretions of betaine, dimethylglycine and glucose were measured on morning urine samples as the ratio to urine creatinine. Statistical determinants of the post-methionine load increase in homocysteine were identified in multiple linear regression models.
RESULTS: Plasma betaine concentrations and urinary betaine excretions were significantly (p > 0.001) more variable in the subjects with diabetes compared with the controls. Dimethylglycine excretion (p = 0.00014) and plasma dimethylglycine concentrations (p = 0.039) were also more variable. In diabetes, plasma betaine was a significant negative determinant (p > 0.001) of the post-methionine load increase in homocysteine. However, it was not conclusive that this was different from the relationship in the controls. In the patients with diabetes, a strong relationship was found between urinary betaine excretion and urinary glucose excretion (but not with plasma glucose).
CONCLUSIONS: Both high and low plasma betaine concentrations, and high and low urinary betaine excretions, are more prevalent in diabetes. The availability of betaine affects the response in the methionine load test. The benefits of increasing betaine intake should be investigated.

Lever, M., et al., Variability of plasma and urine betaine in diabetes mellitus and its relationship to methionine load test responses: an observational study. Cardiovasc Diabetol, 2012. 11(1): p. 34.

Excess methyl donors can be protective against prostate cancer progression

Insufficient dose of dietary methyl groups are associated with a host of conditions ranging from neural tube defects to cancer.On the other hand, it is not certain what effect excess dietary methyl groups could have on cancer. This is especially true for prostate cancer, a disease that is characterized by increasing DNA methylation changes with increasing grade of the cancer. In this three-part study in animals, we look at (i) the effect of excess methyl donors on the growth rate of prostate cancer in vivo, (ii) the ability of 5-aza-20- deoxycytidine (AdC), a demethylating agent, to demethylate in the presence of excess dietary methyl donors, and (iii) the effect of in utero feeding of excess methyl donors to the later onset of prostate cancer. The results show that when mice are fed a dietary excess of methyl donors, we do not see (i) an increase in the growth rate of DU-145 and PC-3 xenografts in vivo, or (ii) interference in the ability of AdC to demethylate the promoters of androgen receptor or Reprimo of prostate cancer xenografts but (iii) a protective effect on the development of higher grades of prostate cancer in the "Hi-myc" mouse model of prostate cancer which were fed the increased methyl donors in utero. We conclude that the impact of dietary methyl donors on prostate cancer progression depends upon the timing of exposure to the dietary agents. When fed before the onset of cancer, that is, in utero, excess methyl donors can have a protective effect on the progression of cancer.

Shabbeer, S., et al., Progression of prostate carcinogenesis and dietary methyl donors: temporal dependence. Cancer Prev Res, 2012. 5(2): p. 229-39.

Betaine reduces the expression of inflammatory adipokines caused by hypoxia in human adipocytes

Obesity is characterised by a state of chronic low-grade inflammation and the elevated circulating and tissue levels of inflammatory markers, including inflammation-related adipokines, released from white adipose tissue. The expression and release of these adipokines generally rises as the adipose tissue expands and hypoxic conditions start to develop within the tissue. Here, the effect of betaine, a trimethylglycine having a biological role as an osmolyte and a methyl donor, on the expression of inflammation-related markers was tested in human adipocytes under hypoxia. Differentiated adipocytes were cultivated under low (1 %) oxygen tension for 8-20 h. The expression of different adipokines, including IL-6, leptin, PPARgamma, TNF-alpha and adiponectin, was measured by quantitative PCR by determining the relative mRNA level from the adipocytes. Hypoxia, in general, led to a decrease in the expression of PPARgamma mRNA in human adipocytes, whereas the expression levels of leptin and IL-6 mRNA were substantially increased by hypoxia. The cultivation of adipocytes under hypoxia also led to a reduction in the expression of TNF-alpha mRNA. The results showed that hypoxia increased the relative quantification of leptin gene transcription, and that betaine (250 mumol/l) reduced this effect, caused by low oxygen conditions. Under hypoxia, betaine also reduced the mRNA level of the pro-inflammatory markers IL-6 and TNF-alpha. These results demonstrate that the extensive changes in the expression of inflammation-related adipokines in human adipocytes caused by hypoxia can be diminished by the presence of physiologically relevant concentrations of betaine.
Olli, K., et al., Betaine reduces the expression of inflammatory adipokines caused by hypoxia in human adipocytes. Br J Nutr, 2012: p. 1-7.

Betaine homocysteine methyltransferase is active in the mouse blastocyst and promotes inner cell mass development

Methyltransferases are an important group of enzymes with diverse roles that include epigenetic gene regulation. The universal donor of methyl groups for methyltransferases is S-adenosylmethionine (AdoMet), which in most cells is synthesized using methyl groups carried by a derivative of folic acid. Another mechanism for AdoMet synthesis uses betaine as the methyl donor via the enzyme betaine-homocysteine methyltransferase (BHMT, EC 2.1.1.5), but it has been considered to be significant only in liver. Here, we show that mouse preimplantation embryos contain endogenous betaine; Bhmt mRNA is first expressed at the morula stage; BHMT is abundant at the blastocyst stage but not other preimplantation stages, and BHMT activity is similarly detectable in blastocyst homogenates but not those of two-cell or morula stage embryos. Knockdown of BHMT protein levels and reduction of enzyme activity using Bhmt-specific antisense morpholinos or a selective BHMT inhibitor resulted in decreased development of embryos to the blastocyst stage in vitro and a reduction in inner cell mass cell number in blastocysts. The detrimental effects of BHMT knockdown were fully rescued by the immediate methyl-carrying product of BHMT, methionine. A physiological role for betaine and BHMT in blastocyst viability was further indicated by increased fetal resorption following embryo transfer of BHMT knockdown blastocysts versus control. Thus, mouse blastocysts are unusual in being able to generate AdoMet not only by the ubiquitous folate-dependent mechanism but also from betaine metabolized by BHMT, likely a significant pool of methyl groups in blastocysts.
Lee, M.B., et al., Betaine homocysteine methyltransferase is active in the mouse blastocyst and promotes inner cell mass development. J Biol Chem, 2012. 287(39): p. 33094-103

Supplementation of high-fat diet with betaine alleviated HF-induced adipose tissue 4-hydroxynonenal increase and attenuated plasma adiponectin decline

Although well-established, the underlying mechanisms involved in obesity-related plasma adiponectin decline remain elusive. Oxidative stress is associated with obesity and insulin resistance and considered to contribute to the progression toward obesity-related metabolic disorders. In this study, we investigated the effects of 4-hydroxynonenal (4-HNE), the most abundant lipid peroxidation end product, on adiponectin production and its potential implication in obesity-related adiponectin decrease. Long-term high-fat diet feeding led to obesity in mouse, accompanied by decreased plasma adiponectin and increased adipose tissue 4-HNE content. Exposure of adipocytes to exogenous 4-HNE resulted in decreased adiponectin secretion in a dose-dependent manner, which was consistent with significantly decreased intracellular adiponectin protein abundance. In contrast, adiponectin gene expression was significantly elevated by 4-HNE treatment, which was concomitant with increased peroxisome proliferator-activated receptor gamma (PPAR-gamma) gene expression and transactivity. The effect was abolished by T0070907, a PPAR-gamma antagonist, suggesting that PPAR-gamma activation plays a critical role in this process. To gain insight into mechanisms involved in adiponectin protein decrease, we examined the effects of 4-HNE on adiponectin protein degradation. Cycloheximide (CHX)-chase assay revealed that 4-HNE exposure accelerated adiponectin protein degradation, which was prevented by MG132, a potent proteasome inhibitor. Immunoprecipitation assay showed that 4-HNE exposure increased ubiquitinated adiponectin protein levels. These data altogether indicated that 4-HNE enhanced adiponectin protein degradation via ubiquitin-proteasome system. Finally, we demonstrated that supplementation of HF diet with betaine, an antioxidant and methyl donor, alleviated high-fat-induced adipose tissue 4-HNE increase and attenuated plasma adiponectin decline. Taken together, our findings suggest that the lipid peroxidation product 4-HNE can differentially regulates adiponectin gene expression and protein abundance and may play a mechanistic role in obesity-related plasma adiponectin decline.

Wang, Z., et al., 4-Hydroxynonenal differentially regulates adiponectin gene expression and secretion via activating PPARgamma and accelerating ubiquitin-proteasome degradation. Mol Cell Endocrinol, 2011. 349(2): p. 222-31

Betaine induces differential and selective conformational stability and enhances aggregation in some proteins in the presence of surfactants

In this study, we extensively report the effect of glycine betaine during the refolding of partially folded bovine alpha-lactalbumin (alpha-LA) in presence of hexadecyl trimethyl ammonium bromide (HTAB), and Ribonuclease A (RNAse A) in presence of sodium dodecyl sulfate (SDS) by different complementary biophysical, light scattering, and microscopic techniques. Though a substantial refolding/compaction was observed in both the studied proteins, the fluorescence studies contradicted the finding obtained from circular dichroism spectroscopy (CD) in case of alpha-LA. CD stopped flow showed extensive presence of intermediates during the refolding of proteins which could potentially lead to aggregation. The aggregates as observed in dynamic light scattering (DLS), in alpha-LA were massive as compared to RNAse A and was directly proportional to betaine concentration. The zeta potential confirmed that the aggregates are a direct manifestation of strong aggregating and/or immense preferential excluding tendency of GB and not because of charge neutralization; however a possible role of conformational change as observed in FTIR spectroscopy cannot be completely ruled out. In contrary though RNAse A showed a substantial refolding, the final state of the folded protein was significantly different from the native state. These findings for alpha-LA and RNAse A were further supported by electron microscopic and thermodynamic studies. We thus propose that betaine has a strong macromolecular excluding tendency, primarily directed to shield the hydrophobic exposure either by refolding or aggregation, and depending on the hydrophobicity of the proteins, the functional restoration of the protein is manifested.

Misra, P.P. and N. Kishore, Glycine betaine: A widely reported osmolyte induces differential and selective conformational stability and enhances aggregation in some proteins in the presence of surfactants. Biopolymers, 2012. 97(12): p. 933-49.

Choline and betaine food sources and intakes in Taiwanese

Choline and betaine are involved in several similar health-relevant metabolic pathways, but the foods sources are different. We have assessed their intakes (individual, sums and ratios) from a dominantly Chinese food cultural point of view. A representative free-living Taiwanese population aged 13-64 years was drawn from the Nutrition and Health Survey in Taiwan (NAHSIT) 1993-1996. Food intake was derived from interviews as 24-hour recalls. The USDA database, with adaptations for Taiwan, provided choline and betaine food compositions. Major food contributors of these nutrients were identified and compared with data from the US Framingham offspring study. Mean and variance reduced median nutrient intakes were calculated. Top ten major food contributors of choline in Taiwan were eggs, pork, chicken, fish, soybean and its products, dark leafy vegetables, dairy, fruit, wheat products and light leafy vegetables in sequence. For betaine, the top ten were dark leafy vegetables, wheat products, fish, pork, bread, chicken, cake/cookies, grain-based alcoholic beverages, rice and its products and sauces. The main contributors of choline in Taiwan and the USA were, respectively, eggs and red meat; and for betaine, greens were similarly best contributor. The rankings of the main food contributors of choline and betaine differed substantially between Taiwan and the USA. The total daily intakes (mean+/-SE, mg) in Taiwan for choline were 372+/-19 (median=348) in men and 265+/-9 (median 261) for women; for betaine, values were 101+/-3 (median 93) in men and 78+/-8 (median 76) for women. These allow for health outcome considerations.
Chu, D.M., et al., Choline and betaine food sources and intakes in Taiwanese. Asia Pac J Clin Nutr, 2012. 21(4): p. 547-57