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

Graduate Student Literature Review: Exploring choline's important roles as a nutrient for transition dairy cows

In late gestation and in the first weeks postpartum, lipid droplets accumulate in the hepatic tissue resulting in approximately 40% to 50% of the dairy cows developing hepatic lipidosis in the first weeks of lactation. Elevated concentrations of triacylglycerol in the hepatic tissue are associated with increased risk of peripartum diseases and impaired productive performance. Cows with hepatic lipidosis need to dispose the excess of hepatic triacylglycerol, but this is a slow process in the bovine liver and relies on primary mechanisms such as complete oxidation and ketogenesis because of the limited export of triacylglycerols as lipoproteins. Choline is a lipotropic compound because, among other functions, it facilitates the export of lipids from the liver. Supplementing choline as rumen-protected choline (RPC) to diets of feed-restricted dairy cows reduces the degree of triacylglycerol infiltration into the hepatic parenchyma in part by enhancing export of triacylglycerol as nascent lipoprotein. The reduced accumulation of triacylglycerol in hepatic tissue in feed-restricted cows fed RPC might affect secondary pathways involved in hepatic disposal of fatty acids such as increased cellular autophagy and lipophagy and minimize endoplasmic reticulum stress response and hepatocyte inflammation. Collectively, these effects on secondary pathways might further reduce the severity of hepatic lipidosis in cows. One of the benefits of supplementing RPC is improved fat digestibility, perhaps because choline, through phosphatidylcholines, facilitates lipid transport within the enterocyte by increasing the synthesis of chylomicrons. Finally, when supplemented during the transition period, RPC improves productive performance of cows, irrespective of their body condition, that extends well beyond the period of supplementation. This review summarizes the current understanding of hepatic lipidosis in early lactation, recapitulates the absorption, transport and metabolism of choline, and discusses its role on hepatic metabolism and gastrointestinal functions, which collectively results in improved performance in dairy cows.

The effects of exposure to and timing of a choline-deficient diet during pregnancy and early postnatal life on the skeletal muscle transcriptome of the offspring

BACKGROUND & AIMS

Nonalcoholic fatty liver disease (NAFLD) is related to muscle loss, but the precise mechanism underlying this association remains unclear. The aim of the present study was thus to determine the influence of maternal fatty liver and dietary choline deficiency during pregnancy and/or lactation periods on the skeletal muscle gene expression profile among 24-day-old male rat offspring.

METHODS

Histological examination of skeletal muscle tissue specimens obtained from offspring of dams suffering from fatty liver, provided with proper choline intake during pregnancy and lactation (NN), fed a choline-deficient diet during both periods (DD), deprived of choline only during pregnancy (DN), or only during lactation (ND), was performed. The global transcriptome pattern was assessed using a microarray approach (Affymetrix® Rat Gene 2.1 ST Array Strip). The relative expression of selected genes was validated by real-time PCR (qPCR).

RESULTS

Morphological differences in fat accumulation in skeletal muscle related to choline supply were observed. The global gene expression profile was consistent with abnormal morphological changes. Mettl21c gene was overexpressed in all choline-deficient groups compared to the NN group, while two genes, Cdkn1a and S100a4, were downregulated. Processes of protein biosynthesis were upregulated, and processes related to cell proliferation and lipid metabolism were inhibited in DD, DN, and ND groups compared to the NN group.

CONCLUSIONS

Prenatal and early postnatal exposure to fatty liver and dietary choline deficiency leads to changes in the transcriptome profile in skeletal muscle of 24-day old male rat offspring and is associated with muscle damage, but the mechanism of it seems to be different at different developmental stages of life. Adequate choline intake during pregnancy and lactation can prevent severe muscle disturbance in the progeny of females suffering from fatty liver.

Exploring the Gut Microbiota-Muscle Axis in Duchenne Muscular Dystrophy

The gut microbiota plays a pivotal role in maintaining the dynamic balance of intestinal epithelial and immune cells, crucial for overall organ homeostasis. Dysfunctions in these intricate relationships can lead to inflammation and contribute to the pathogenesis of various diseases. Recent findings uncovered the existence of a gut-muscle axis, revealing how alterations in the gut microbiota can disrupt regulatory mechanisms in muscular and adipose tissues, triggering immune-mediated inflammation. In the context of Duchenne muscular dystrophy (DMD), alterations in intestinal permeability stand as a potential origin of molecules that could trigger muscle degeneration via various pathways. Metabolites produced by gut bacteria, or fragments of bacteria themselves, may have the ability to migrate from the gut into the bloodstream and ultimately infiltrate distant muscle tissues, exacerbating localized pathologies. These insights highlight alternative pathological pathways in DMD beyond the musculoskeletal system, paving the way for nutraceutical supplementation as a potential adjuvant therapy. Understanding the complex interplay between the gut microbiota, immune system, and muscular health offers new perspectives for therapeutic interventions beyond conventional approaches to efficiently counteract the multifaceted nature of DMD.

Plasma-Induced Changes in the Metabolome Following Vistula Tart Cherry Consumption

Evidence suggests that tart cherry (TC) supplementation has beneficial effects on health indices and recovery following strenuous exercise. However, little is known about the mechanisms and how TC might modulate the human metabolome. The aim of this study was to evaluate the influence of an acute high- and low-dose of Vistula TC supplementation on the metabolomic profile in humans. In a randomised, double-blind, placebo controlled, cross-over design, 12 healthy participants (nine male and three female; mean ± SD age, stature, and mass were 29 ± 7 years old, 1.75 ± 0.1 m, and 77.3 ± 10.5 kg, respectively) visited the laboratory on three separate occasions (high dose; HI, low dose; LO, or placebo), separated by at least seven days. After an overnight fast, a baseline venous blood sample was taken, followed by consumption of a standardised breakfast and dose conditions (HI, LO, or placebo). Subsequent blood draws were taken 1, 2, 3, 5, and 8 h post consumption. Following sample preparation, an untargeted metabolomics approach was adopted, and the extracts analysed by LCMS/MS. When all time points were collated, a principal component analysis showed a significant difference between the conditions (p < 0.05), such that the placebo trial had homogeneity, and HI showed greater heterogeneity. In a sub-group analysis, cyanidine-3-O-glucoside (C3G), cyanidine-3-O-rutinoside (C3R), and vanillic acid (VA) were detected in plasma and showed significant differences (p < 0.05) following acute consumption of Vistula TC, compared to the placebo group. These results provide evidence that phenolics are bioavailable in plasma and induce shifts in the metabolome following acute Vistula TC consumption. These data could be used to inform future intervention studies where changes in physiological outcomes could be influenced by metabolomic shifts following acute supplementation.

Genome-Wide Analysis of Exertional Rhabdomyolysis in Sickle Cell Trait Positive African Americans

Sickle cell trait (SCT), although generally a benign carrier state of hemoglobin S (HbAS), is a risk factor for exertional rhabdomyolysis (ERM), a rare but potentially fatal consequence of highly intense physical exercise, particularly among active-duty military personnel and high-performance athletes. The association between SCT and ERM is poorly understood. The objective of this study was to elucidate the genetic basis of ERM in an SCT-positive African American cohort. SCT-positive African Americans with a personal history of ERM (cases, n = 30) and without history of ERM (controls, n = 53) were enrolled in this study. Whole-genome sequencing was performed on DNA samples isolated from peripheral white blood cells. Participants' demographic, behavioral, and medical history information was obtained. An additional 131 controls were extracted from SCT-positive subjects of African descent from the 1000 Genomes Project. SCT carriers with ERM were characterized by myotoxicity features, significant muscle involvement dominated by muscle weakness, and severe pain and substantial increase in serum creatine kinase, with a mean value of 50,480 U/L. A distinctive feature of the SCT individuals with ERM was exertional collapse, which was reported in 53.3% of the cases in the study cohort. An important factor for the development of ERM was the duration and frequency of strenuous physical activity in the cases compared to the controls. Whole-genome sequencing identified 79,696 protein-coding variants. Genome-wide association analysis revealed that the p.C477R, rs115958260 variant in the SLC44A3 gene was significantly associated with ERM event in SCT-positive African Americans. The study results suggest that a combination of vigorous exercise and a genetic predisposing factor is involved in ERM.

The Relationship of Circulating Choline and Choline-Related Metabolite Levels with Health Outcomes: A Scoping Review of Genome-Wide Association Studies and Mendelian Randomization Studies

Choline is essential for proper liver, muscle, brain, lipid metabolism, cellular membrane composition, and repair. Understanding genetic determinants of circulating choline metabolites can help identify new determinants of choline metabolism, requirements, and their link to disease endpoints. We conducted a scoping review to identify studies assessing the association of genetic polymorphisms on circulating choline and choline-related metabolite concentrations and subsequent associations with health outcomes. This study follows the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement scoping review extension. Literature was searched to September 28, 2022, in 4 databases: Embase, MEDLINE, Web of Science, and the Biological Science Index. Studies of any duration in humans were considered. Any genome-wide association study (GWAS) investigating genetic variant associations with circulating choline and/or choline-related metabolites and any Mendelian randomization (MR) study investigating the association of genetically predicted circulating choline and/or choline-related metabolites with any health outcome were considered. Qualitative evidence is presented in summary tables. From 1248 total reviewed articles, 53 were included (GWAS = 27; MR = 26). Forty-two circulating choline-related metabolites were tested in association with genetic variants in GWAS studies, primarily trimethylamine N-oxide, betaine, sphingomyelins, lysophosphatidylcholines, and phosphatidylcholines. MR studies investigated associations between 52 total unique choline metabolites and 66 unique health outcomes. Of these, 47 significant associations were reported between 16 metabolites (primarily choline, lysophosphatidylcholines, phosphatidylcholines, betaine, and sphingomyelins) and 27 health outcomes including cancer, cardiovascular, metabolic, bone, and brain-related outcomes. Some articles reported significant associations between multiple choline types and the same health outcome. Genetically predicted circulating choline and choline-related metabolite concentrations are associated with a wide variety of health outcomes. Further research is needed to assess how genetic variability influences choline metabolism and whether individuals with lower genetically predicted circulating choline and choline-related metabolite concentrations would benefit from a dietary intervention or supplementation.

Activation of a non-neuronal cholinergic system in visceral white adipose tissue of obese mice and humans

BACKGROUND AND OBJECTIVES

Since white adipose tissue (WAT) lacks parasympathetic cholinergic innervation, the source of the acetylcholine (ACh) acting on white adipocyte cholinergic receptors is unknown. This study was designed to identify ACh-producing cells in mouse and human visceral WAT and to determine whether a non-neuronal cholinergic system becomes activated in obese inflamed WAT.

METHODS

Mouse epididymal WAT (eWAT) and human omental fat were studied in normal and obese subjects. The expression of the key molecules involved in cholinergic signaling was evaluated by qRT-PCR and western blotting whereas their tissue distribution and cellular localization were investigated by immunohistochemistry, confocal microscopy and in situ hybridization. ACh levels were measured by liquid chromatography/tandem mass spectrometry. The cellular effects of ACh were assessed in cultured human multipotent adipose-derived stem cell (hMADS) adipocytes.

RESULTS

In mouse eWAT, diet-induced obesity modulated the expression of key cholinergic molecular components and, especially, raised the expression of choline acetyltransferase (ChAT), the ACh-synthesizing enzyme, which was chiefly detected in interstitial macrophages, in macrophages forming crown-like structures (CLSs), and in multinucleated giant cells (MGCs). The stromal vascular fraction of obese mouse eWAT contained significantly higher ACh and choline levels than that of control mice. ChAT was undetectable in omental fat from healthy subjects, whereas it was expressed in a number of interstitial macrophages, CLSs, and MGCs from some obese individuals. In hMADS adipocytes stressed with tumor necrosis factor α, ACh, alone or combined with rivastigmine, significantly blunted monocyte chemoattractant protein 1 and interleukin 6 expression, it partially but significantly, restored adiponectin and GLUT4 expression, and promoted glucose uptake.

CONCLUSIONS

In mouse and human visceral WAT, obesity induces activation of a macrophage-dependent non-neuronal cholinergic system that is capable of exerting anti-inflammatory and insulin-sensitizing effects on white adipocytes.

Gut dysbiosis aggravates cognitive deficits, amyloid pathology and lipid metabolism dysregulation in a transgenic mouse model of Alzheimer's disease

Gut dysbiosis, a well-known risk factor to triggers the progression of Alzheimer's disease (AD), is strongly associated with metabolic disturbance. Trimethylamine N-oxide (TMAO), produced in the dietary choline metabolism, has been found to accelerate neurodegeneration in AD pathology. In this study, the cognitive function and gut microbiota of TgCRND8 (Tg) mice of different ages were evaluated by Morris water maze task (MWMT) and 16S rRNA sequencing, respectively. Young pseudo germ-free (PGF) Tg mice that received faecal microbiota transplants from aged Tg mice and wild-type (WT) mice were selected to determine the role of the gut microbiota in the process of neuropathology. Excessive choline treatment for Tg mice was used to investigate the role of abnormal choline metabolism on the cognitive functions. Our results showed that gut dysbiosis, neuroinflammation response, Aβ deposition, tau hyperphosphorylation, TMAO overproduction and cyclin-dependent kinase 5 (CDK5)/transcription 3 (STAT3) activation occurred in Tg mice age-dependently. Disordered microbiota of aged Tg mice accelerated AD pathology in young Tg mice, with the activation of CDK5/STAT3 signaling in the brains. On the contrary, faecal microbiota transplantation from WT mice alleviated the cognitive deficits, attenuated neuroinflammation, Aβ deposition, tau hyperphosphorylation, TMAO overproduction and suppressed CDK5/STAT3 pathway activation in Tg mice. Moreover, excessive choline treatment was also shown to aggravate the cognitive deficits, Aβ deposition, neuroinflammation and CDK5/STAT3 pathway activation. These findings provide a novel insight into the interaction between gut dysbiosis and AD progression, clarifying the important roles of gut microbiota-derived substances such as TMAO in AD neuropathology.

The Effect of Choline and Resistance Training on Strength and Lean Mass in Older Adults

Choline plays many important roles, including the synthesis of acetylcholine, and may affect muscle responses to exercise. We previously observed correlations between low choline intake and reduced gains in strength and lean mass following a 12-week resistance exercise training (RET) program for older adults. To further explore these findings, we conducted a randomized controlled trial. Three groups of 50-to-69-year-old healthy adults underwent a 12-week RET program (3x/week, 3 sets, 8-12 reps, 70% of maximum strength (1RM)) and submitted >48 diet logs (>4x/week for 12 weeks). Participants' diets were supplemented with 0.7 mg/kg lean/d (low, n = 13), 2.8 mg/kg lean/d (med, n = 11), or 7.5 mg/kg lean/d (high, n = 13) of choline from egg yolk and protein powder. The ANCOVA tests showed that low choline intake, compared with med or high choline intakes, resulted in significantly diminished gains in composite strength (leg press + chest press 1RM; low, 19.4 ± 8.2%; med, 46.8 ± 8.9%; high, 47.4 ± 8.1%; p = 0.034) and thigh-muscle quality (leg press 1RM/thigh lean mass; low, 12.3 ± 9.6%; med/high, 46.4 ± 7.0%; p = 0.010) after controlling for lean mass, protein, betaine, and vitamin B12. These data suggest that low choline intake may negatively affect strength gains with RET in older adults.

The interactive relationship of dietary choline and betaine with physical activity on circulating creatine kinase (CK), metabolic and glycemic markers, and anthropometric characteristics in physically active young individuals

BACKGROUND

There is conflicting evidence on the relationship between dietary choline and betaine with metabolic markers and anthropometric characteristics. The aim of this study is to investigate the relationship between the interaction effects of dietary choline and betaine and physical activity (PA) on circulating creatine kinase (CK), metabolic and glycemic markers, and anthropometric characteristics in active youth.

METHODS

In this cross-sectional study, data were collected from 120 to 18 to 35-year-old people. The food frequency questionnaire was used to assess dietary data; United States Department of Agriculture website was used to calculate choline and betaine in foods. CK, fasting blood sugar (FBS) and lipid profile markers were measured with ELISA kits. Low-density lipoprotein, and insulin sensitivity markers were calculated. Sociodemographic status, physical activity, and anthropometric characteristics were assessed based on a valid and reliable method. Analysis of co-variance (ANCOVA) tests adjusted for sex, PA, age, energy, and body mass index were used.

RESULTS

Increasing dietary betaine and total choline and betaine was positively related to weight, waist-to-hip ratio, fat-free mass and bone mass (P < 0.05). Increasing dietary betaine lowered total cholesterol (P = 0.032) and increased high density lipoprotein (HDL) (P = 0.049). The interaction effect of dietary choline and physical activity improved insulin resistance (P < 0.05). As well as dietary betaine interacted with physical activity increased HDL (P = 0.049). In addition, dietary total choline and betaine interacted with physical activity decreased FBS (P = 0.047).

CONCLUSIONS

In general, increasing dietary choline and betaine along with moderate and high physical activity improved insulin resistance, increased HDL, and lowered FBS in the higher tertiles of dietary choline and betaine.

Vegetable Oil-Peroxidation Product 'Hydroxynonenal' Causes Hepatocyte Injury and Steatosis via Hsp70.1 and BHMT Disorders in the Monkey Liver

Hsp70.1 has a dual function as a chaperone protein and lysosomal stabilizer. In 2009, we reported that calpain-mediated cleavage of carbonylated Hsp70.1 causes neuronal death by inducing lysosomal rupture in the hippocampal CA1 neurons of monkeys after transient brain ischemia. Recently, we also reported that consecutive injections of the vegetable oil-peroxidation product 'hydroxynonenal' induce hepatocyte death via a similar cascade in monkeys. As Hsp70.1 is also related to fatty acid β-oxidation in the liver, its deficiency causes fat accumulation. The genetic deletion of betaine-homocysteine S-methyltransferase (BHMT) was reported to perturb choline metabolism, inducing a decrease in phosphatidylcholine and resulting in hepatic steatosis. Here, focusing on Hsp70.1 and BHMT disorders, we studied the mechanisms of hepatocyte degeneration and steatosis. Monkey liver tissues with and without hydroxynonenal injections were compared using proteomics, immunoblotting, immunohistochemical, and electron microscopy-based analyses. Western blotting showed that neither Hsp70.1 nor BHMT were upregulated, but an increased cleavage was observed in both. Proteomics showed a marked downregulation of Hsp70.1, albeit a two-fold increase in the carbonylated BHMT. Hsp70.1 carbonylation was negligible, in contrast to the ischemic hippocampus, which was associated with ~10-fold increments. Although histologically, the control liver showed very little lipid deposition, numerous tiny lipid droplets were seen within and around the degenerating/dying hepatocytes in monkeys after the hydroxynonenal injections. Electron microscopy showed permeabilization/rupture of lysosomal membranes, dissolution of the mitochondria and rough ER membranes, and proliferation of abnormal peroxisomes. It is probable that the disruption of the rough ER caused impaired synthesis of the Hsp70.1 and BHMT proteins, while impairment of the mitochondria and peroxisomes contributed to the sustained generation of reactive oxygen species. In addition, hydroxynonenal-induced disorders facilitated degeneration and steatosis in the hepatocytes.

Impact of Antarctic krill oil supplementation on skeletal muscle injury recovery after resistance exercise

BACKGROUND

Antarctic krill oil (KO) is a natural source of n-3 polyunsaturated fatty acids (n-3 PUFAs), and is rich in phospholipids, Eicosapentaenoic acid (EPA), Docosahexaenoic acid (DHA), astaxanthin, flavonoids, vitamins, trace elements, and other bioactive substances. KO has been confirmed to have anti-inflammatory and immunomodulatory effects. n-3 PUFAs also have been purported to improve the recovery of muscular performance. Moreover, the phospholipids present in KO can enhance n-3 PUFA bioavailability because of its higher absorption rate in plasma compared to fish oil. Astaxanthin, found in Antarctic KO, is a red carotenoid and powerful antioxidant that inhibits oxidative stress after intense exercise. Hence, we examined the effect of KO supplementation on the recovery of exercise by measuring muscular performance, oxidant/antioxidant and anti-inflammatory activity, and the markers of muscle damage following a rigorous bout of resistance exercise.

METHODS

30 college-aged resistance-trained males (20.4 ± 0.92 years, 74.09 ± 7.23 kg, 180.13 ± 4.72 cm) were randomly supplemented with 3 g/d KO or placebo (PL) for 3 days and continued to consume after resistance exercise for 3 days until the experiment finished. Before supplementation, pre-exercise performance assessments of knee isokinetic strength, 20 m sprint, hexagon test, and blood serum creatine kinase (CK), lactate dehydrogenase (LDH), superoxide dismutase (SOD), total antioxidant capacity (T-AOC), reactive oxygen species (ROS), malondialdehyde (MDA), interleukin-2 (IL-2), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) were completed. Then after 3 days of supplementation, participants completed a bout of muscle-damaging exercise, and subsequently, they performed and repeated the exercise performance assessments and blood-related indicators tests immediately (0 h), as well as at 6, 24, 48, and 72 h post-muscle-damaging exercise.

RESULTS

Compared to the PL group, the serum CK of KO group was significantly lower at 24 h and 48 h post-exercise; the hexagon test time of the KO group was significantly lower than that of the PL group at 6 h and 24 h post-exercise; the KO group's isokinetic muscle strength showed different degrees of recovery than that of the PL group at 24 h and 48 h, and even over-recovery at 72 h post-exercise; the SOD level of the KO group was significantly higher than that of the PL group at 0, 6, and 24 h after exercise; the T-AOC level of the KO group was significantly higher than that of the PL group at 0, 6, and 72 h after exercise; the MDA level of the KO group was significantly lower than that of the PL group at 6 h; and there was no significant difference in serum IL-2, IL-6, and TNF-α between the two groups.

CONCLUSION

Our results demonstrated that 3 g/d KO supplementation and continued supplementation after exercise can alleviate exercise-induced muscle damage (EIMD) and promote post-exercise recovery.

Molecular Mechanisms Underlying Qi-Invigorating Effects in Traditional Medicine: Network Pharmacology-Based Study on the Unique Functions of Qi-Invigorating Herb Group

Qi-invigorating herbs (QIHs) are a group of herbs that invigorate Qi, the most vital force for maintaining the physiological functions of the human body in traditional medicine. However, the mechanism underlying the Qi-invigorating effects remains unclear. This study aimed to elucidate the unique mechanisms of QIHs based on unique compounds, using a network pharmacology approach. QIHs and their compounds were identified using existing literature and the TCMSP database, respectively. Subsequently, a method was proposed to screen for unique compounds that are common in QIHs but rare in other traditional herbs. Unique compounds’ targets were predicted using the TCMSP, BATMAN-TCM, and SwissTargetPrediction databases. Finally, enriched GO and KEGG pathways were obtained using DAVID to uncover the biomolecular functions and mechanisms. Thirteen unique compounds, mainly including amino acids and vitamins that participate in energy metabolism and improve Qi deficiency syndrome, were identified among the eight QIHs. GO and KEGG pathway analyses revealed that these compounds commonly participate in neuroactive ligand–receptor interaction and the metabolism of amino acids, and are related to the components of mitochondria and neuronal cells. Our results appropriately reflect the characteristics of traditional Qi-invigorating effects; therefore, this study facilitates the scientific interpretation of Qi functions and provides evidence regarding the treatment effectiveness of QIHs.

Feasibility of 18F-Fluorocholine PET for Evaluating Skeletal Muscle Atrophy in a Starved Rat Model

Imaging techniques for diagnosing muscle atrophy and sarcopenia remain insufficient, although various advanced diagnostic methods have been established. We explored the feasibility of ¹⁸F-fluorocholine (¹⁸F-FCH) positron emission tomography/computed tomography (PET/CT) for evaluating skeletal muscle atrophy, as an imaging technique that tracks choline level changes in muscles. Cell uptake in L6 cells by ¹⁸F-FCH was performed in a complete medium containing serum (untreated group, UN) and a serum-free medium (starved group, ST). Small-animal-dedicated PET/CT imaging with ¹⁸F-FCH was examined in in-vivo models with rats that were starved for 2 days to cause muscle atrophy. After the hind limbs were dissected, starvation-induced in-vivo models were anatomically confirmed by reverse-transcription polymerase chain reaction to evaluate the expression levels of the atrophy markers muscle RING-finger protein-1 (MuRF-1) and atrogin-1. ¹⁸F-FCH uptake was lower in the starvation-induced cells than in the untreated group, and in-vivo PET uptake also revealed a similar tendency (the average standardized uptake value (SUV_mean) = 0.26 ± 0.06 versus 0.37 ± 0.07, respectively). Furthermore, the expression levels of MuRF-1 and atrogin-1 mRNA were significantly increased in the starvation-induced muscle atrophy of rats compared to the untreated group. ¹⁸F-FCH PET/CT may be a promising tool for diagnosing skeletal muscle atrophy.

Multiomics Approach to Precision Sports Nutrition: Limits, Challenges, and Possibilities

Most sports nutrition guidelines are based on group average responses and professional opinion. Precision nutrition for athletes aims to improve the individualization of nutrition practices to optimize long-term performance and health. This is a 2-step process that first involves the acquisition of individual-specific, science-based information using a variety of sources including lifestyle and medical histories, dietary assessment, physiological assessments from the performance lab and wearable sensors, and multiomics data from blood, urine, saliva, and stool samples. The second step consists of the delivery of science-based nutrition advice, behavior change support, and the monitoring of health and performance efficacy and benefits relative to cost. Individuals vary widely in the way they respond to exercise and nutritional interventions, and understanding why this metabolic heterogeneity exists is critical for further advances in precision nutrition. Another major challenge is the development of evidence-based individualized nutrition recommendations that are embraced and efficacious for athletes seeking the most effective enhancement of performance, metabolic recovery, and health. At this time precision sports nutrition is an emerging discipline that will require continued technological and scientific advances before this approach becomes accurate and practical for athletes and fitness enthusiasts at the small group or individual level. The costs and scientific challenges appear formidable, but what is already being achieved today in precision nutrition through multiomics and sensor technology seemed impossible just two decades ago.

Krill-Oil-Dependent Increases in HS-Omega-3 Index, Plasma Choline and Antioxidant Capacity in Well-Conditioned Power Training Athletes

There is evidence that both omega-3 polyunsaturated fatty acids (n-3 PUFAs) and choline can influence sports performance, but information establishing their combined effects when given in the form of krill oil during power training protocols is missing. The purpose of this study was therefore to characterize n-3 PUFA and choline profiles after a one-hour period of high-intensity physical workout after 12 weeks of supplementation. Thirty-five healthy power training athletes received either 2.5 g/day of Neptune krill oil^TM (550 mg EPA/DHA and 150 mg choline) or olive oil (placebo) in a randomized double-blind design. After 12 weeks, only the krill oil group showed a significant HS-Omega-3 Index increase from 4.82 to 6.77% and a reduction in the ARA/EPA ratio (from 50.72 to 13.61%) (p < 0.001). The krill oil group showed significantly higher recovery of choline concentrations relative to the placebo group from the end of the first to the beginning of the second exercise test (p = 0.04) and an 8% decrease in total antioxidant capacity post-exercise versus 21% in the placebo group (p = 0.35). In conclusion, krill oil can be used as a nutritional strategy for increasing the HS-Omega-3 Index, recover choline concentrations and address oxidative stress after intense power trainings.

Increasing dietary choline attenuates spatial memory deficits resulting from exposure to the chemotherapeutic agents cyclophosphamide and doxorubicin

BACKGROUND

Choline supplementation (+Ch) improves cognitive function in impaired animals and humans. Chemotherapy-related cognitive deficits (CRCDs) occur in cancer patients, and these deficits persist following treatment, adversely impacting quality of life. To date, there are no approved treatments for this condition.

AIM

Because +Ch improves impaired memory, it was of interest to determine whether +Ch can attenuate spatial memory deficits induced by the chemotherapeutic agents doxorubicin (DOX) and cyclophosphamide (CYP).

METHODS

Female BALB/C mice, 64 days of age, were trained in the Morris water maze and baseline performance determined on day 15. Following baseline assessment, mice were placed on +Ch diet (2.0% Ch) or remained on standard diet (0.12% Ch). Mice received intravenous injections of DOX (2.5 mg/kg) and CYP (25 mg/kg), or equivalent volumes of saline (0.9% NaCl), on days 16, 23, 30, and 37, and spatial memory was assessed weekly from day 22 to 71.

RESULTS

DOX and CYP produced a prolonged impairment in spatial memory as indicated by an increased latency to the correct zone (p < 0.05), and a decrease in time in the correct zone (p < 0.05), % of total swim distance in the correct zone (p < 0.05) and % entries to the correct zone (p < 0.05). These effects were attenuated by +Ch.

CONCLUSION

Although it remains to be determined whether this effect extends to other cognitive domains and whether +Ch is prophylactic or therapeutic, these findings suggest that +Ch may be an effective intervention for CRCDs.

Urine metabolomic biomarkers for prediction of isolated fetal congenital heart defect

OBJECTIVE

To identify maternal second and third trimester urine metabolomic biomarkers for the detection of fetal congenital heart defects (CHDs).

STUDY DESIGN

This was a prospective study. Metabolomic analysis of randomly collected maternal urine was performed, comparing pregnancies with isolated, non-syndromic CHDs versus unaffected controls. Mass spectrometry (liquid chromatography and direct injection and tandem mass spectrometry, LC-MS-MS) as well as nuclear magnetic resonance spectrometry, ¹H NMR, were used to perform the analyses between 14 0/7 and 37 0/7 weeks gestation. A total of 36 CHD cases and 41 controls were compared. Predictive algorithms using urine markers alone or combined with, clinical and ultrasound (US) (four-chamber view) predictors were developed and compared.

RESULTS

A total of 222 metabolites were identified, of which 16 were overlapping between the two platforms. Twenty-three metabolite concentrations were found in significantly altered in CHD gestations on univariate analysis. The concentration of methionine was most significantly altered. A predictive algorithm combining metabolites (histamine, choline, glucose, formate, methionine, and carnitine) plus US four-chamber view achieved an AUC = 0.894; 95% CI, 0814-0.973 with a sensitivity of 83.8% and specificity of 87.8%. Enrichment pathway analysis identified several lipid related pathways that are dysregulated in CHD, including phospholipid biosynthesis, phosphatidylcholine biosynthesis, phosphatidylethanolamine biosynthesis, and fatty acid metabolism. This could be consistent with the increased risk of CHD in diabetic pregnancies.

CONCLUSIONS

We report a novel, noninvasive approach, based on the analysis of maternal urine for isolated CHD detection. Further, the dysregulation of lipid- and folate metabolism appears to support prior data on the mechanism of CHD.

Effects of acute heat stress on salivary metabolites in growing pigs: an analysis using nuclear magnetic resonance-based metabolomics profiling

Heat stress (HS) causes adverse impacts on pig production and health. A potential biomarker of HS is required to predict its occurrence and thereby better manage pigs under HS. Information about the saliva metabolome in heat-stressed pigs is limited. Therefore, this study was aimed to investigate the effects of acute HS on the saliva metabolome and identify metabolites that could be used as potential biomarkers. Growing pigs (n = 6, 3 boars, and 3 gilts) were raised in a thermal neutral (TN; 25°C) environment for a 5-d adaptation period (CON). After adaptation, the pigs were first exposed to HS (30°C; HS30) and then exposed to higher HS (33°C; HS33) for 24 h. Saliva was collected after adaptation, first HS, and second HS, respectively, for metabolomic analysis using ¹H-nuclear magnetic resonance spectroscopy. Four metabolites had significantly variable importance in the projection (VIP > 1; p < 0.05) different levels in TN compared to HS groups from all genders (boars and gilts). However, sex-specific characteristics affected metabolites (glutamate and leucine) by showing the opposite results, indicating that HS was less severe in females than in males. A decrease in creatine levels in males and an increase in creatine phosphate levels in females would have contributed to a protective effect from protein degradation by muscle damage. The results showed that HS led to an alteration in metabolites related to energy and protein. Protection from muscle damage may be attributed to the alteration in protein-related metabolites. However, energy-related metabolites showed opposing results according to sex-specific characteristics, such as sex hormone levels and subcutaneous fat layer. This study had shown that saliva samples could be used as a noninvasive method to evaluate heat-stressed pigs. And the results in this study could be contributed to the development of a diagnostic tool as a noninvasive biomarker for managing heat-stressed pigs.

Epigenetics of the developing and aging brain: Mechanisms that regulate onset and outcomes of brain reorganization

Brain development is a life-long process that encompasses several critical periods of transition, during which significant cognitive changes occur. Embryonic development, puberty, and reproductive senescence are all periods of transition that are hypersensitive to environmental factors. Rather than isolated episodes, each transition builds upon the last and is influenced by consequential changes that occur in the transition before it. Epigenetic marks, such as DNA methylation and histone modifications, provide mechanisms by which early events can influence development, cognition, and health outcomes. For example, parental environment influences imprinting patterns in gamete cells, which ultimately impacts gene expression in the embryo which may result in hypersensitivity to poor maternal nutrition during pregnancy, raising the risks for cognitive impairment later in life. This review explores how epigenetics induce and regulate critical periods, and also discusses how early environmental interactions prime a system towards a particular health outcome and influence susceptibility to disease or cognitive impairment throughout life.

Effects of Krill Oil and Race Distance on Serum Choline and Choline Metabolites in Triathletes: A Field Study

Choline is an essential nutrient that has been implicated in athletic performance due to its role in maintaining normal muscle function. The concentration of free choline in serum may decrease during long-distance high-intensity exercise, yet few nutritional strategies to counteract this potentially performance-depleting loss in choline have been investigated outside the laboratory. This exploratory field study was performed to investigate if pre-race supplementation with phosphatidylcholine from krill oil can counteract the expected drop in choline and some of its metabolites during triathlon competitions. Forty-seven triathletes, 12 females and 35 males ranging in age from 25 to 61 years, were recruited from participants in the Ironman-distance Norseman Xtreme triathlon and the Sprint/Olympic-distance Oslo Triathlon. Twenty-four athletes were randomly allocated to the krill oil group, receiving 4 g of SuperbaBoost™ krill oil daily for 5 weeks prior to the race, and 23 athletes were randomly allocated to the placebo group, receiving 4 g of mixed vegetable oil daily. Blood samples were obtained before the race, immediately after completion of the race, and the day after the race for analysis of choline and its metabolites. The results showed that serum choline concentrations significantly decreased from pre-race to race finish in all races, with a more pronounced decrease observed in the Ironman-distance Norseman Xtreme triathlon (34% decrease) relative to the Sprint/Olympic-distance Oslo Triathlon (15% decrease). A reduction in betaine was also observed, while dimethylglycine (DMG) concentrations remained stable across all time points. Significantly higher concentrations of choline (9.4% on average) and DMG (21.4% on average) were observed in the krill oil compared to the placebo group, and the krill oil group showed a significantly greater increase in serum choline following race completion. In conclusion, krill oil may help to prevent that circulating choline concentrations become limiting during endurance competitions.

Choline: An Essential Nutrient for Skeletal Muscle

BACKGROUND

Choline is an essential micronutrient with a pivotal role in several metabolic pathways contributing to liver, neurological, and hematological homeostasis. Although choline is commonly administered to improve physical performance, its effects on muscle are still unclear. The aim of this scoping review is to analyze the role of choline on skeletal muscle in terms of biological effects and clinical implications.

METHODS

A technical expert panel (TEP) of 6 medical specialists with expertise in muscle physiology and skeletal muscle disorders performed the review following the PRISMA-ScR (Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews) model. The TEP planned a research on PubMed selecting "choline" as MeSH (Medical Subject Headings) term adding to PubMed Search Builder the terms "skeletal muscle" and "muscle striated". TEP considered for eligibility articles published in the last 30 years, including original researches, particularly in vitro studies, and animal and clinical studies in the English language.

RESULTS

From the 1239 studies identified, TEP included 14 studies, 3 in vitro, 9 animal, and 2 clinical studies.

CONCLUSIONS

Our scoping review elucidates and summarizes the crucial role of choline in modulating muscle fat metabolism, muscle proteins homeostasis, and the modulation of inflammation and autophagy.

Sport Nutrigenomics: Personalized Nutrition for Athletic Performance

An individual's dietary and supplement strategies can influence markedly their physical performance. Personalized nutrition in athletic populations aims to optimize health, body composition, and exercise performance by targeting dietary recommendations to an individual's genetic profile. Sport dietitians and nutritionists have long been adept at placing additional scrutiny on the one-size-fits-all general population dietary guidelines to accommodate various sporting populations. However, generic "one-size-fits-all" recommendations still remain. Genetic differences are known to impact absorption, metabolism, uptake, utilization and excretion of nutrients and food bioactives, which ultimately affects a number of metabolic pathways. Nutrigenomics and nutrigenetics are experimental approaches that use genomic information and genetic testing technologies to examine the role of individual genetic differences in modifying an athlete's response to nutrients and other food components. Although there have been few randomized, controlled trials examining the effects of genetic variation on performance in response to an ergogenic aid, there is a growing foundation of research linking gene-diet interactions on biomarkers of nutritional status, which impact exercise and sport performance. This foundation forms the basis from which the field of sport nutrigenomics continues to develop. We review the science of genetic modifiers of various dietary factors that impact an athlete's nutritional status, body composition and, ultimately athletic performance.

Choline transport for phospholipid synthesis: An emerging role of choline transporter-like protein 1

IMPACT STATEMENT

This review will provide a summary of recent advances in choline transport research and highlight important novel areas of focus in the field.

Plasma lipidome reveals critical illness and recovery from human Ebola virus disease

Ebola virus disease (EVD) often leads to severe and fatal outcomes in humans with early supportive care increasing the chances of survival. Profiling the human plasma lipidome provides insight into critical illness as well as diseased states, as lipids have essential roles as membrane structural components, signaling molecules, and energy sources. Here we show that the plasma lipidomes of EVD survivors and fatalities from Sierra Leone, infected during the 2014-2016 Ebola virus outbreak, were profoundly altered. Focusing on how lipids are associated in human plasma, while factoring in the state of critical illness, we found that lipidome changes were related to EVD outcome and could identify states of disease and recovery. Specific changes in the lipidome suggested contributions from extracellular vesicles, viremia, liver dysfunction, apoptosis, autophagy, and general critical illness, and we identified possible targets for therapies enhancing EVD survival.

Folate and choline absorption and uptake: Their role in fetal development

SCOPE

In this review, we attempt to assess how choline and folate transporters affect fetal development. We focus on how the expression of these transporters in response to choline and folate intake affects transport effectiveness. We additionally describe allelic variants of the genes encoding these transporters and their phenotypic effects.

METHODS AND RESULTS

We made an extensive review of recent articles describing role of choline and folate - with particularly emphasize on their transporters - in fetal development. Folate and choline are necessary for the proper functioning of the cell and body. During pregnancy, the requirements of these nutrients increase because of elevated maternal demand and the rapid division of fetal cells. The concentrations of folate and choline in cells depend on food intake, the absorption of nutrients, and the cellular transport system, which is tissue-specific and developmentally regulated. Relatively few studies have investigated the role of choline transporters in fetal development.

CONCLUSIONS

In this review we show relations between functioning of folate and choline transporters and fetal development.

Choline: The Underconsumed and Underappreciated Essential Nutrient

Choline has been recognized as an essential nutrient by the Food and Nutrition Board of the National Academies of Medicine since 1998. Its metabolites have structural, metabolic, and regulatory roles within the body. Humans can endogenously produce small amounts of choline via the hepatic phosphatidylethanolamine N-methyltransferase pathway. However, the nutrient must be consumed exogenously to prevent signs of deficiency. The Adequate Intake (AI) for choline was calculated at a time when dietary intakes across the population were unknown for the nutrient. Unlike the traditional National Academy of Medicine approach of calculating an AI based on observed or experimentally determined approximations or estimates of intake by a group (or groups) of healthy individuals, calculation of the AI for choline was informed in part by a depletion-repletion study in adult men who, upon becoming deficient, developed signs of liver damage. The AI for other gender and life-stage groups was calculated based on standard reference weights, except for infants 0 to 6 months, whose AI reflects the observed mean intake from consuming human breast milk. Recent analyses indicate that large portions of the population (ie, approximately 90% of Americans), including most pregnant and lactating women, are well below the AI for choline. Moreover, the food patterns recommended by the 2015-2020 Dietary Guidelines for Americans are currently insufficient to meet the AI for choline in most age-sex groups. An individual's requirement for choline is dependent on common genetic variants in genes required for choline, folate, and 1-carbon metabolism, potentially increasing more than one-third of the population's susceptibly to organ dysfunction. The American Medical Association and American Academy of Pediatrics have both recently reaffirmed the importance of choline during pregnancy and lactation. New and emerging evidence suggests that maternal choline intake during pregnancy, and possibly lactation, has lasting beneficial neurocognitive effects on the offspring. Because choline is found predominantly in animal-derived foods, vegetarians and vegans may have a greater risk for inadequacy. With the 2020-2025 Dietary Guidelines for Americans recommending expansion of dietary information for pregnant women, and the inclusion of recommendations for infants and toddlers 0 to 2 years, better communication of the role that choline plays, particularly in the area of neurocognitive development, is critical. This narrative review summarizes the peer-reviewed literature and discussions from the 2018 Choline Science Summit, held in Washington, DC, in February 2018.

Dietary Choline Intake: Current State of Knowledge Across the Life Cycle

Choline, an essential dietary nutrient for humans, is required for the synthesis of the neurotransmitter, acetylcholine, the methyl group donor, betaine, and phospholipids; and therefore, choline is involved in a broad range of critical physiological functions across all stages of the life cycle. The current dietary recommendations for choline have been established as Adequate Intakes (AIs) for total choline; however, dietary choline is present in multiple different forms that are both water-soluble (e.g., free choline, phosphocholine, and glycerophosphocholine) and lipid-soluble (e.g., phosphatidylcholine and sphingomyelin). Interestingly, the different dietary choline forms consumed during infancy differ from those in adulthood. This can be explained by the primary food source, where the majority of choline present in human milk is in the water-soluble form, versus lipid-soluble forms for foods consumed later on. This review summarizes the current knowledge on dietary recommendations and assessment methods, and dietary choline intake from food sources across the life cycle.

Neuroprotective Actions of Dietary Choline

Choline is an essential nutrient for humans. It is a precursor of membrane phospholipids (e.g., phosphatidylcholine (PC)), the neurotransmitter acetylcholine, and via betaine, the methyl group donor S-adenosylmethionine. High choline intake during gestation and early postnatal development in rat and mouse models improves cognitive function in adulthood, prevents age-related memory decline, and protects the brain from the neuropathological changes associated with Alzheimer’s disease (AD), and neurological damage associated with epilepsy, fetal alcohol syndrome, and inherited conditions such as Down and Rett syndromes. These effects of choline are correlated with modifications in histone and DNA methylation in brain, and with alterations in the expression of genes that encode proteins important for learning and memory processing, suggesting a possible epigenomic mechanism of action. Dietary choline intake in the adult may also influence cognitive function via an effect on PC containing eicosapentaenoic and docosahexaenoic acids; polyunsaturated species of PC whose levels are reduced in brains from AD patients, and is associated with higher memory performance, and resistance to cognitive decline.

Time-course microarrays reveal early activation of the immune transcriptome in a choline-deficient mouse model of liver injury

AIMS

Choline-deficient diet is extensively used as a model of nonalcoholic fatty liver disease (NAFLD). In this study, we explored genes in the liver for which the expression changed in response to the choline-deficient (CD) diet.

MAIN METHODS

Male CD-1 mice were divided into two groups and fed a CD diet with or without 0.2% choline bitartrate for one or three weeks. Hepatic levels of choline metabolites were analyzed by using liquid chromatography mass spectrometry and hepatic gene expression profiles were examined by DNA microarray analysis.

KEY FINDINGS

The CD diet lowered liver choline metabolites after one week and exacerbated fatty liver between one and three weeks. We identified >300 genes whose expression was significantly altered in the livers of mice after consumption of this CD diet for one week and showed that liver gene expression profiles could be classified into six distinct groups. This study showed that STAT1 and interferon-regulated genes was up-regulated after the CD diet consumption and that the Stat1 mRNA level was negatively correlated with liver phosphatidylcholine level. Stat1 mRNA expression was actually up-regulated in isolated hepatocytes from the mouse liver with the CD diet.

SIGNIFICANCE

This study provides insight into the genomic effects of the CD diet through the Stat1 expression, which might be involved in NAFLD development.

Choline Supplementation During Pregnancy Protects Against Gestational Lipopolysaccharide-Induced Inflammatory Responses

OBJECTIVES

To estimate the effects and mechanisms of choline, an essential nutrient and a selective α7 nicotinic acetylcholine receptor (α7nAChR) agonist, on the prevention of symptoms and the effects on the cholinergic anti-inflammatory pathways (CAP) in a lipopolysaccharide (LPS)-induced inflammatory response in a rat model.

METHODS

Inflammation was induced by LPS treatment (1.0 μg LPS/kg body weight) on gestational day (GD) 14. Nonpregnant and pregnant Sprague Dawley rats were placed on a normal choline diet (1.1 g/kg) or supplemented choline diet (5.0 g/kg) from GDs 1 to 20. Systolic blood pressure (SBP), urinary albumin, and pregnancy outcomes were recorded. On GD 20, serum and placentas were assayed for cytokines. Western blots were used to determine the expression of placenta α7nAChR and components of the α7nAChR-CAP, including nuclear factor-κB (NF-κB) and protein kinase B (AKT). Immunohistochemistry was used to localize placental sites for the p65 subunit of NF-κB.

RESULTS

Lipopolysaccharide significantly increased SBP and urinary albumin and decreased pregnancy outcomes, and these effects were partially reversed by higher choline treatment. Choline supplementation also significantly attenuated the LPS-induced increase in serum and placental inflammatory cytokines, decreased the expression of placental α7nAChR, lowered the activation of NF-κB signaling in placenta mononuclear cells, and inhibited placental AKT phosphorylation.

CONCLUSION

This study confirms that LPS induces inflammatory conditions in pregnant rats and shows that choline supplementation protects against the inflammatory symptoms through its action on α7nAChR and CAP. These observations have important implications for the prevention and treatment of inflammatory responses associated with pregnancy.

Role of Choline in the Modulation of Degenerative Processes: In Vivo and In Vitro Studies

The purpose of the present study was to examine the nutraceutical potential of choline as an added value to its well-known brain nutrient role. Several toxicity, antitoxicity, genotoxicity, antigenotoxicity, and longevity endpoints were checked in the somatic mutation and recombination test in in vivo Drosophila animal model. Cytotoxicity in human leukemia-60 cell line (HL-60) promyelocytic and NIH3T3 mouse fibroblast cells, proapoptotic DNA fragmentation, comet assay, methylation status, and macroautophagy (MA) activity were tested in in vitro assays. Choline is not only safe but it is also able to protect against the DNA damage caused by an oxidative genotoxin. Moreover, it improves the life extension in the animal model. The in vitro results show that it is able to exhibit genetic damage against leukemia HL-60 cells. Single-strand breaks in DNA are observed at the molecular level in treatments with choline, although only a significant hypermethylation on the long interspersed elements-1 and a hypomethylation on the satellite-alpha DNA repetitive DNA sequences of HL-60 cells at the lowest concentration (0.447 mM) were observed. Besides, choline decreased MA at the lower assayed concentration and the MA response to topoisomerase inhibitor (etoposide) is maintained in the presence of treatment with 0.22 mM choline. Taking into account the hopeful results obtained in the in vivo and in vitro assays, choline could be proposed as a substance with an important nutraceutical value for different purposes.

Looking Beyond Structure: Membrane Phospholipids of Skeletal Muscle Mitochondria

Skeletal muscle mitochondria are highly dynamic and are capable of tremendous expansion to meet cellular energetic demands. Such proliferation in mitochondrial mass requires a synchronized supply of enzymes and structural phospholipids. While transcriptional regulation of mitochondrial enzymes has been extensively studied, there is limited information on how mitochondrial membrane lipids are generated in skeletal muscle. Herein we describe how each class of phospholipids that constitute mitochondrial membranes are synthesized and/or imported, and summarize genetic evidence indicating that membrane phospholipid composition represents a significant modulator of skeletal muscle mitochondrial respiratory function. We also discuss how skeletal muscle mitochondrial phospholipids may mediate the effect of diet and exercise on oxidative metabolism.

Identification of new genetic polymorphisms that alter the dietary requirement for choline and vary in their distribution across ethnic and racial groups

Effect alleles (alleles with a polymorphism that is associated with the effect being measured) in a small number of single-nucleotide polymorphisms (SNPs) are known to influence the dietary requirement for choline. In this study, we examined a much larger number of SNPs (n=200) in 10 genes related to choline metabolism for associations with development of organ dysfunction (liver or muscle) when 79 humans were fed a low-choline diet. We confirmed that effect alleles in SNPs such as the C allele of PEMT rs12325817 increase the risk of developing organ dysfunction in women when they consume a diet low in choline, and we identified novel effect alleles, such as the C allele of CHKA SNP rs7928739, that alter dietary choline requirements. When fed a low-choline diet, some people presented with muscle damage rather than liver damage; several effect alleles in SLC44A1 (rs7873937, G allele; rs2771040, G; rs6479313, G; rs16924529, A; and rs3199966, C) and one in CHKB (rs1557502, A) were more common in these individuals. This suggests that pathways related to choline metabolism are more important for normal muscle function than previously thought. In European, Mexican, and Asian Americans, and in individuals of African descent, we examined the prevalence of the effect alleles in SNPs that alter choline requirement and found that they are differentially distributed among people of different ethnic and racial backgrounds. Overall, our study has identified novel genetic variants that modulate choline requirements and suggests that the dietary requirement for choline may be different across racial and ethnic groups.-Da Costa, K.-A., Corbin, K. D., Niculescu, M. D., Galanko, J. A., Zeisel, S. H. Identification of new genetic polymorphisms that alter the dietary requirement for choline and vary in their distribution across ethnic and racial groups.

Carnitine modulates crucial myocardial adenosine triphosphatases and acetylcholinesterase enzyme activities in choline-deprived rats

Choline is an essential nutrient, and choline deficiency has been associated with cardiovascular morbidity. Choline is also the precursor of acetylcholine (cholinergic component of the heart's autonomic nervous system), whose levels are regulated by acetylcholinesterase (AChE). Cardiac contraction-relaxation cycles depend on ion gradients established by pumps like the adenosine triphosphatases (ATPases) Na(+)/K(+)-ATPase and Mg(2+)-ATPase. This study aimed to investigate the impact of dietary choline deprivation on the activity of rat myocardial AChE (cholinergic marker), Na(+)/K(+)-ATPase, and Mg(2+)-ATPase, and the possible effects of carnitine supplementation (carnitine, structurally relevant to choline, is used as an adjunct in treating cardiac diseases). Adult male albino Wistar rats were distributed among 4 groups, and were fed a standard or choline-deficient diet for one month with or without carnitine in their drinking water (0.15% w/v). The enzyme activities were determined spectrophotometrically in the myocardium homogenate. Choline deficiency seems to affect the activity of the aforementioned parameters, but only the combination of choline deprivation and carnitine supplementation increased myocardial Na(+)/K(+)-ATPase activity along with a concomitant decrease in the activities of Mg(2+)-ATPase and AChE. The results suggest that carnitine, in the setting of choline deficiency, modulates cholinergic myocardial neurotransmission and the ATPase activity in favour of cardiac work efficiency.

Plasma choline, nicotine exposure, and risk of low bone mineral density and hip fracture: the Hordaland health study

Choline, obtained from diet and formed by biosynthesis, is the immediate precursor of betaine. Animal studies suggest an impact of choline on bone metabolism. We examined the associations of plasma choline and betaine with bone mineral density (BMD), the risk of hip fractures, and possible effect-modification by nicotine exposure. The Hordaland Health Study (1998 to 2000) included 7074 women and men (ages 46 to 49 or 71 to 74 years). In 5315, BMD was measured. The oldest (n = 3311) were followed for hip fractures through 2009. Risk associations were studied by logistic and Cox regression by comparing the lowest and middle tertiles with the highest, as well as trends across tertiles of plasma choline and betaine. In analyses adjusted for sex and age, participants in the lowest (odds ratio [OR] = 2.00, 95% confidence interval [CI] 1.69-2.37) and middle (OR = 1.39, CI 1.17-1.66) tertiles of plasma choline had an increased risk of low BMD (lowest quintile) (p trend < 0.001). Separate analyses for sex and age groups revealed the strongest relations in elderly women (lowest tertile: OR = 2.84, CI 1.95-4.14; middle tertile: OR = 1.80, CI 1.22-2.67, p trend < 0.001), and highest OR among those in the lowest tertile who were exposed to nicotine (OR = 4.56, CI 1.87-11.11). Low plasma choline was also associated with an increased risk of hip fracture in elderly women and men (lowest tertile: hazard ratio [HR] = 1.45, CI 1.08-1.94; middle tertile: HR = 1.13, CI 0.83-1.54, p trend = 0.012). In elderly women, the HR for hip fracture was 1.90 (CI 1.32-2.73) and 1.36 (CI 0.92-1.99) (p trend < 0.001) for lowest and middle tertiles of choline, and the highest HR was found among women in the lowest tertile exposed to nicotine (HR = 2.68, CI 1.16-6.19). Plasma betaine was not related to BMD or hip fracture. Low plasma choline was associated with low BMD in both sexes and increased the risk of hip fracture in elderly women. These results should motivate further studies on choline, nicotine exposure, and bone metabolism.

Plasma choline and betaine correlate with serum folate, plasma S-adenosyl-methionine and S-adenosyl-homocysteine in healthy volunteers

BACKGROUND

Choline is essential for mammalian cell function. It plays a critical role in cell membrane integrity, neurotransmission, cell signaling and lipid metabolism. Moreover, choline is involved in methylation in two ways: a) its synthesis requires methyl groups donated by S-adenosyl-methionine (AdoMet); and b) choline oxidation product betaine methylates homocysteine (Hcy) to methionine (Met) and produces dimethylglycine. This later donates one carbon units to tetrahydrofolate (THF).

METHODS

To evaluate the correlations of choline and betaine with folate, AdoMet, S-anenosyl-homocysteine (AdoHcy), total homocysteine (tHcy), and DNA methylation, choline, betaine and dimethylglycine were measured by LC-MS/MS in plasma of 109 healthy volunteers, in whom folate, AdoMet, AdoHcy, tHcy, and DNA methylation have previously been reported.

RESULTS

Using a bivariate model, choline and betaine showed strong positive correlations with folate (r = 0.346 and r = 0.226), AdoHcy (r = 0.468 and r = 0.296), and correlated negatively with AdoMet/AdoHcy ratio (r = – 0.246 and r = – 0.379). Only choline was positively correlated with AdoMet (r = 0.453). Using a multivariate linear regression model, choline correlated strongly with folate ( β = 17.416), AdoMet ( β = 61.272), and AdoHcy ( β = 9.215). Betaine correlated positively with folate ( β = 0.133) and negatively with tHcy ( β = – 0.194) ratio. Choline is an integral part of folate and methylation pathways.

CONCLUSIONS

Our data highlight the importance of integrating choline in studies concerning addressing pathological conditions related to folate, homocysteine and methylation metabolism.

Metabolic crosstalk between choline/1-carbon metabolism and energy homeostasis

There are multiple identified mechanisms involved in energy metabolism, insulin resistance and adiposity, but there are here-to-fore unsuspected metabolic factors that also influence these processes. Studies in animal models suggest important links between choline/1-carbon metabolism and energy homeostasis. Rodents fed choline deficient diets become hypermetabolic. Mice with deletions in one of several different genes of choline metabolism have phenotypes that include increased metabolic rate, decreased body fat/lean mass ratio, increased insulin sensitivity, decreased ATP production by mitochondria, or decreased weight gain on a high fat diet. In addition, farmers have recognized that the addition of a metabolite of choline (betaine) to cattle and swine feed reduces body fat/lean mass ratio. Choline dietary intake in humans varies over a > three-fold range, and genetic variation exists that modifies individual requirements for this nutrient. Although there are some epidemiologic studies in humans suggesting a link between choline/1-carbon metabolism and energy metabolism, there have been no controlled studies in humans that were specifically designed to examine this relationship.

Neuroprotective actions of perinatal choline nutrition

Choline is an essential nutrient for humans. Studies in rats and mice have shown that high choline intake during gestation or the perinatal period improves cognitive function in adulthood, prevents memory decline of old age, and protects the brain from damage and cognitive and neurological deterioration associated with epilepsy and hereditary conditions such as Down's and Rett syndromes. These behavioral changes are accompanied by modified patterns of expression of hundreds of cortical and hippocampal genes including those encoding proteins central for learning and memory processing. The effects of choline correlate with cerebral cortical changes in DNA and histone methylation, thus suggesting an epigenomic mechanism of action of perinatal choline.

Nutrition in pregnancy: the argument for including a source of choline

Women, during pregnancy and lactation, should eat foods that contain adequate amounts of choline. A mother delivers large amounts of choline across the placenta to the fetus, and after birth she delivers large amounts of choline in milk to the infant; this greatly increases the demand on the choline stores of the mother. Adequate intake of dietary choline may be important for optimal fetal outcome (birth defects, brain development) and for maternal liver and placental function. Diets in many low income countries and in approximately one-fourth of women in high income countries, like the United States, may be too low in choline content. Prenatal vitamin supplements do not contain an adequate source of choline. For women who do not eat foods containing milk, meat, eggs, or other choline-rich foods, a diet supplement should be considered.

Choline intake influences phosphatidylcholine DHA enrichment in nonpregnant women but not in pregnant women in the third trimester

BACKGROUND

Phosphatidylcholine (PC) produced via the S-adenosylmethionine-dependent phosphatidylethanolamine (PE) N-methyltransferase (PEMT) pathway is enriched with docosahexaenoic acid (DHA). DHA plays a critical role in fetal development and is linked to health endpoints in adulthood. It is unknown whether choline, which can serve as a source of S-adenosylmethionine methyl groups, influences PC-DHA or the PC:PE ratio in pregnant and nonpregnant women.

OBJECTIVE

This study tested whether choline intake affects indicators of choline-related lipid metabolism, including erythrocyte and plasma PC-DHA and PC:PE ratios, in pregnant women in the third trimester and nonpregnant women.

DESIGN

Pregnant (n = 26) and nonpregnant (n = 21) women consumed 480 or 930 mg choline/d and a daily DHA supplement for 12 wk. Blood was collected at baseline and at the midpoint and end of the study. PC-DHA was analyzed as the proportion of total PC fatty acids.

RESULTS

Pregnant women had greater (P = 0.002) PC-DHA concentrations than did nonpregnant women at baseline. The proportion of erythrocyte and plasma PC-DHA increased (P ≤ 0.002) in pregnant and nonpregnant women regardless of choline intake. However, in nonpregnant women, consumption of 930 mg choline/d led to greater (P < 0.001) erythrocyte PC-DHA and a more rapid increase (P < 0.001) in plasma PC-DHA. Lower (P = 0.001-0.024) erythrocyte and plasma PC:PE in pregnant women was not modified by choline intake.

CONCLUSIONS

A higher choline intake may increase PEMT activity, resulting in greater PC-DHA enrichment of the PC molecule in nonpregnant women. Increased production of PC-DHA during pregnancy indicates elevated PEMT activity and a higher demand for methyl donors. This trial was registered at clinicaltrials.gov as NCT01127022.

One-carbon metabolism in psychiatric illness

The cost of psychiatric illness to the UK economy was recently estimated at pound77 billion annually. Despite years of research no firm aetiological explanation exists, and with no physiological or biochemical markers diagnosis is made entirely on a behavioural basis. All current pharmacological therapies are associated with serious long-term side effects. Substantial evidence supports the involvement of one-carbon cycle dysregulation in psychiatric illness, but this is not currently used as a basis for diagnosis or treatment. The present paper reviews the evidence for one-carbon cycle dysregulation in schizophrenic, bipolar, depressed and autistic patients. Also presented are novel findings from the field of epigenetics, which demonstrate how the one-carbon cycle-derived methyl donor S-adenosylmethionine influences the expression of key genes in the brain affecting memory, learning, cognition and behaviour, genes whose expression is reduced to varying degrees in these patient groups. Clinical evidence that nutritional supplements can rectify one-carbon cycle activity, and restore normal gene expression, suggests a novel approach to the development of biochemical tests and simple, non-harmful treatments for some psychiatric patients. Conversely, evidence from animal studies highlights the dangers of exposing the unborn fetus to very high dietary levels of folic acid, a one-carbon cycle cofactor. Fetal adaptations to a high-folate environment may interfere with folate metabolism postnatally, with serious consequences for the epigenetic regulation of gene expression. The public health implications of these diverse scenarios indicate an urgent need for further research in this field.

Blood biomarkers of methylation in Down syndrome and metabolic simulations using a mathematical model

SCOPE

The study tests the metabolites of the methylation cycle in individuals with Down syndrome (DS) and applies a mathematical model in order to change this cycle by nutritional factors.

METHODS AND RESULTS

We measured concentrations of the metabolites related to the methylation cycle in the blood of 35 young individuals with DS and 47 controls of comparable age. Moreover, we applied a mathematical model to learn more about the regulation of the methylation cycle in DS. Concentrations of cystathionine, cysteine, betaine, choline, dimethylglycine, S-adenosylhomocysteine (SAH), S-adenosylmethionine (SAM), and holotranscobalamin were significantly higher in DS compared to the controls. The median SAM/SAH ratio was lower in DS and that of methionine and reduced glutathione did not differ significantly between the groups. The mathematical model showed that enhanced methionine turnover and accelerated Hcy-remethylation might explain the shift in the methylation cycle in DS.

CONCLUSION

In addition to the DS-related excess of cystathionine beta synthase (CBS) activity, increases in the activities of MS and betaine homocysteine methyl transferase, and in methionine input were necessary to account for the changes in metabolite levels observed in DS. A low-methionine diet might offer a perspective for reversing the metabolic imbalance in DS, but this awaits clinical investigations.

Choline nutrition programs brain development via DNA and histone methylation

Choline is an essential nutrient for humans. Metabolically choline is used for the synthesis of membrane phospholipids (e.g. phosphatidylcholine), as a precursor of the neurotransmitter acetylcholine, and, following oxidation to betaine, choline functions as a methyl group donor in a pathway that produces S-adenosylmethionine. As a methyl donor choline influences DNA and histone methylation--two central epigenomic processes that regulate gene expression. Because the fetus and neonate have high demands for choline, its dietary intake during pregnancy and lactation is particularly important for normal development of the offspring. Studies in rodents have shown that high choline intake during gestation improves cognitive function in adulthood and prevents memory decline associated with old age. These behavioral changes are accompanied by electrophysiological, neuroanatomical, and neurochemical changes and by altered patterns of expression of multiple cortical and hippocampal genes including those encoding key proteins that contribute to the biochemical mechanisms of learning and memory. These actions of choline are observed long after the exposure to the nutrient ended (months) and correlate with fetal hepatic and cerebral cortical choline-evoked changes in global- and gene-specific DNA cytosine methylation and with dramatic changes of the methylation pattern of lysine residues 4, 9 and 27 of histone H3. Moreover, gestational choline modulates the expression of DNA (Dnmt1, Dnmt3a) and histone (G9a/Ehmt2/Kmt1c, Suv39h1/Kmt1a) methyltransferases. In addition to the central role of DNA and histone methylation in brain development, these processes are highly dynamic in adult brain, modulate the expression of genes critical for synaptic plasticity, and are involved in mechanisms of learning and memory. A recent study documented that in a cohort of normal elderly people, verbal and visual memory function correlated positively with the amount of dietary choline consumption. It will be important to determine if these actions of choline on human cognition are mediated by epigenomic mechanisms or by its influence on acetylcholine or phospholipid synthesis.

Maternal nutritional status, C(1) metabolism and offspring DNA methylation: a review of current evidence in human subjects

Evidence is growing for the long-term effects of environmental factors during early-life on later disease susceptibility. It is believed that epigenetic mechanisms (changes in gene function not mediated by DNA sequence alteration), particularly DNA methylation, play a role in these processes. This paper reviews the current state of knowledge of the involvement of C₁ metabolism and methyl donors and cofactors in maternal diet-induced DNA methylation changes in utero as an epigenetic mechanism. Methyl groups for DNA methylation are mostly derived from the diet and supplied through C₁ metabolism by way of choline, betaine, methionine or folate, with involvement of riboflavin and vitamins B₆ and B₁₂ as cofactors. Mouse models have shown that epigenetic features, for example DNA methylation, can be altered by periconceptional nutritional interventions such as folate supplementation, thereby changing offspring phenotype. Evidence of early nutrient-induced epigenetic change in human subjects is scant, but it is known that during pregnancy C₁ metabolism has to cope with high fetal demands for folate and choline needed for neural tube closure and normal development. Retrospective studies investigating the effect of famine or season during pregnancy indicate that variation in early environmental exposure in utero leads to differences in DNA methylation of offspring. This may affect gene expression in the offspring. Further research is needed to examine the real impact of maternal nutrient availability on DNA methylation in the developing fetus.

Deletion of betaine-homocysteine S-methyltransferase in mice perturbs choline and 1-carbon metabolism, resulting in fatty liver and hepatocellular carcinomas

Betaine-homocysteine S-methyltransferase (BHMT) uses betaine to catalyze the conversion of homocysteine (Hcy) to methionine. There are common genetic polymorphisms in the BHMT gene in humans that can alter its enzymatic activity. We generated the first Bhmt(-/-) mouse to model the functional effects of mutations that result in reduced BHMT activity. Deletion of Bhmt resulted in a 6-fold increase (p < 0.01) in hepatic and an 8-fold increase (p < 0.01) in plasma total Hcy concentrations. Deletion of Bhmt resulted in a 43% reduction in hepatic S-adenosylmethionine (AdoMet) (p < 0.01) and a 3-fold increase in hepatic S-adenosylhomocysteine (AdoHcy) (p < 0.01) concentrations, resulting in a 75% reduction in methylation potential (AdoMet:AdoHcy) (p < 0.01). Bhmt(-/-) mice accumulated betaine in most tissues, including a 21-fold increase in the liver concentration compared with wild type (WT) (p < 0.01). These mice had lower concentrations of choline, phosphocholine, glycerophosphocholine, phosphatidylcholine, and sphingomyelin in several tissues. At 5 weeks of age, Bhmt(-/-) mice had 36% lower total hepatic phospholipid concentrations and a 6-fold increase in hepatic triacyglycerol concentrations compared with WT (p < 0.01), which was due to a decrease in the secretion of very low density lipoproteins. At 1 year of age, 64% of Bhmt(-/-) mice had visible hepatic tumors. Histopathological analysis revealed that Bhmt(-/-) mice developed hepatocellular carcinoma or carcinoma precursors. These results indicate that BHMT has an important role in Hcy, choline, and one-carbon homeostasis. A lack of Bhmt also affects susceptibility to fatty liver and hepatocellular carcinoma. We suggest that functional polymorphisms in BHMT that significantly reduce activity may have similar effects in humans.

Homocysteine as a risk factor for atherosclerosis: is its conversion to s-adenosyl-L-homocysteine the key to deregulated lipid metabolism?

Homocysteine (Hcy) has been recognized for the past five decades as a risk factor for atherosclerosis. However, the role of Hcy in the pathological changes associated with atherosclerosis as well as the pathological mechanisms triggered by Hcy accumulation is poorly understood. Due to the reversal of the physiological direction of the reaction catalyzed by S-adenosyl-L-homocysteine hydrolase Hcy accumulation leads to the synthesis of S-adenosyl-L-homocysteine (AdoHcy). AdoHcy is a strong product inhibitor of S-adenosyl-L-methionine (AdoMet)-dependent methyltransferases, and to date more than 50 AdoMet-dependent methyltransferases that methylate a broad spectrum of cellular compounds including nucleic acids, proteins and lipids have been identified. Phospholipid methylation is the major consumer of AdoMet, both in mammals and in yeast. AdoHcy accumulation induced either by Hcy supplementation or due to S-adenosyl-L-homocysteine hydrolase deficiency results in inhibition of phospholipid methylation in yeast. Moreover, yeast cells accumulating AdoHcy also massively accumulate triacylglycerols (TAG). Similarly, Hcy supplementation was shown to lead to increased TAG and sterol synthesis as well as to the induction of the unfolded protein response (UPR) in mammalian cells. In this review a model of deregulation of lipid metabolism in response to accumulation of AdoHcy in Hcy-associated pathology is proposed.