BackgroundThis study was developed to establish whether betaine was present in the sweat of females and to determine any correlations with other sweat components.MethodsSweat patches were placed on eight trained adolescent Highland dancers (age = 13.6 ± 2.3 yr), who then participated in a dance class for 2 hours. Patches were removed, and the sweat recovered via centrifugation. The sweat was subsequently analyzed for betaine, choline, sodium, potassium, chloride, lactate, glucose, urea and ammonia.ResultsBetaine was present in the sweat of all subjects (232 ± 84 μmol·L-1), which is higher than typically found in plasma. The concentration of several sweat components were correlated, in particular betaine with most other measured components.ConclusionBetaine, an osmoprotectant and methyl donor, is a component of sweat that may be lost from the body in significant amounts.

Choline is an essential nutrient for humans, though some part of this requirement can be met by endogenous synthesis catalyzed by phosphatidylethanolamine N‐methyltransferase (PEMT). Human diets which lack sufficient choline intake can result in organ and muscle dysfunction. Pre‐menopausal women are more resistant to choline deficiency than post‐menopausal women and men. There is evidence in animal models which suggests that estrogen can increase PEMT activity. The goal of this study is to investigate whether and how the PEMT gene is regulated by estrogen. Real Time RT‐PCR revealed gene transcription was increased in a dose‐dependent manner in cultured primary mouse hepatocytes treated with various concentrations of 17B‐estradiol for 24 hours. Protein levels and enzyme activity were also increased. The human PEMT promoter contains eight putative estrogen response elements (EREs) and an Electrophoretic Mobility Shift Assay (EMSA) revealed that a 41 bp segment, which contains two putative EREs (2 and 3), can bind estrogen receptor complexes. Transfection studies, in which the human PEMT promoter is linked to a promoterless luciferase reporter gene, will be used to determine whether estrogen regulates promoter activity. This work supported by NIH grants to SZ(DK55865, AG09525, DK56350).

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We previously identified three functional single nucleotide polymorphisms (SNPs) that modulate sensitivity to dietary choline deficiency‐mediated organ dysfunction: CHDH rs12676, MTHFD1 rs2236225 and PEMT rs12325817. We aimed to broaden our understanding of the contribution of genetic aberrations in the 1‐carbon pathway to choline deficiency sensitivity. We performed targeted next‐generation sequencing on the following genes: ABCB4, BHMT, CBS, CHDH, CHKA, CHKB, MTHFD1, MTHFR, MTR, PCYT1A, PCYT1B, PEMT, SHMT1, SLC44A1, SLC5A7. The subjects in our study were divided into the following groups based on their response to a choline deficient diet: 1) did not exhibit symptoms of choline deficiency (n = 13); 2) had fatty liver and elevated liver enzymes (n = 15); 3) had elevated skeletal muscle creatine phosphokinase (n = 9). Although our study was underpowered, we identified a set of SNPs that are potential novel genetic modifiers of sensitivity to choline deficiency (primarily in PEMT and MTHFD1) and to organ‐specific deficiency symptoms (primarily in SLC44A1). Importantly, principal components analysis identified a set of SNPs that differentiated those who were sensitive to dietary choline deficiency vs. those that were not (PC1 p‐value = 0.018). Our results delineate candidate SNPs for differentiating individuals that are sensitive to dietary choline deficiency. These SNPs warrant further investigation. Grant Funding Source: NIH U24‐CA143848‐03; P30‐CA016086‐37; P50‐CA058223‐19A1 (JP)

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