Lower hepatic CBS and PEMT expression in advanced NAFLD: inferencing strategies to lower homocysteine with a mathematical model

Abstract

Aim: Hepatic homocysteine (Hcy) accumulation promotes inflammation and fibrosis in experimental nonalcoholic fatty liver disease (NAFLD), while vitamin B12 and folate reduce hepatic Hcy and protect animals from nonalcoholic steatohepatitis. This suggests clinical implications for preventing/treating patients with NAFLD. Given the known sex-specific regulation of one-carbon metabolism (OCM), the response to various OCM cofactors may vary by sex and reproductive status. We aimed to strategize an effective Hcy-lowering treatment in broader NAFLD patients while discerning disparities in treatment responses.

Methods: We analyzed existing hepatic microarray data relevant to Hcy metabolism with clinical and histologic data from patients with NAFLD (N = 82), while considering potential age/sex disparities. Additionally, we performed computer simulation analyses using a mathematical model of OCM to predict hepatic Hcy-lowering effects of OCM cofactors by sex.

Results: Of 82 patients with NAFLD, 98% had at least one metabolic feature [i.e., metabolic dysfunction-associated steatotic liver disease (MASLD)]. Lower hepatic gene expressions of cystathionine-beta synthase (CBS) and phosphatidyl- ethanolamine N-methyltransferase (PEMT) were associated with more severe fibrosis in NAFLD, while sub-analysis suggested possible variations by age and sex. The simulation analysis demonstrated sex differences in the Hcy-lowering effects of the OCM cofactors (vitamins B6 and B12, folate, and betaine), with the combination of these cofactors consistently showing the maximum Hcy-lowering effect in both sexes.

Conclusion: We theorize that the combination of OCM cofactors would maximize Hcy-lowering effects in the broader MASLD population. Our findings also underscore the importance of considering sex and age in designing future studies on homocysteine metabolism.

Keywords

Nonalcoholic fatty liver disease (NAFLD) / nonalcoholic steatohepatitis (NASH) / metabolic dysfunction-associated steatotic liver disease (MASLD) / hepatic fibrosis / one-carbon metabolism / homocysteine

References

[1] Tripathi M,Zhou J.Vitamin B₁₂ and folate decrease inflammation and fibrosis in NASH by preventing syntaxin 17 homocysteinylation.J Hepatol2022;77:1246-55

[2] Åberg F,Lundqvist A.Hyperhomocysteinemia predicts liver-related clinical outcomes in the general population.J Hepatol2023;78:e172-4

[3] Xu R,Wang Y,Lv Y.Gender- and age-related differences in homocysteine concentration: a cross-sectional study of the general population of China.Sci Rep2020;10:17401 PMCID:PMC7566483

[4] Zhu Z,Li C,Tao M.Relationship between serum homocysteine and different menopausal stage.Climacteric2020;23:59-64

[5] Sadre-Marandi F,Reed MC.Sex differences in hepatic one-carbon metabolism.BMC Syst Biol2018;12:89 PMCID:PMC6201565

[6] Morris MS,Selhub J.Total homocysteine and estrogen status indicators in the Third National Health and Nutrition Examination Survey.Am J Epidemiol2000;152:140-8

[7] Kim R,Reed MC.One-carbon metabolism during the menstrual cycle and pregnancy.PLoS Comput Biol2021;17:e1009708 PMCID:PMC8741061

[8] Moylan CA,Dellinger A.Hepatic gene expression profiles differentiate presymptomatic patients with mild versus severe nonalcoholic fatty liver disease.Hepatology2014;59:471-82 PMCID:PMC3982589

[9] Kleiner DE, Brunt EM, Van Natta M, et al; Nonalcoholic Steatohepatitis Clinical Research Network. Design and validation of a histological scoring system for nonalcoholic fatty liver disease. Hepatology 2005;41:1313-21.

[10] Jakubowski H.Homocysteine thiolactone: metabolic origin and protein homocysteinylation in humans.J Nutr2000;130:377S-81S

[11] Barathi S,Pasupathi A.Homocysteinethiolactone and paraoxonase: novel markers of diabetic retinopathy.Diabetes Care2010;33:2031-7 PMCID:PMC2928358

[12] Perła-Kaján J,Głowacki R,Jakubowski H.Paraoxonase 1 Q192R genotype and activity affect homocysteine thiolactone levels in humans.FASEB J2018;32:6019-24

[13] Liu YQ,Han F.Suppression effects of betaine-enriched spinach on hyperhomocysteinemia induced by guanidinoacetic acid and choline deficiency in rats.ScientificWorldJournal2014;2014:904501 PMCID:PMC4163418

[14] Fischer LM,Kwock L.Sex and menopausal status influence human dietary requirements for the nutrient choline.Am J Clin Nutr2007;85:1275-85 PMCID:PMC2435503

[15] Kobayashi T,Ozaki A.Vitamin B6 efficacy in the treatment of nonalcoholic fatty liver disease: an open-label, single-arm, single-center trial.J Clin Biochem Nutr2021;68:181-6 PMCID:PMC8046002

[16] Bombardieri G,Bernardi L,Di Palma A.Intestinal absorption of S-adenosyl-L-methionine in humans.Int J Clin Pharmacol Ther Toxicol1983;21:186-8

[17] Jung SB,Kapur A.Association between vitamin B12 deficiency and long-term use of acid-lowering agents: a systematic review and meta-analysis.Intern Med J2015;45:409-16

[18] Liu Q,Quan H.Vitamin B12 status in metformin treated patients: systematic review.PLoS One2014;9:e100379 PMCID:PMC4069007

[19] De Vincentis A,Pihlajamäki J.Genetic variants in the MTHFR are not associated with fatty liver disease.Liver Int2020;40:1934-40

[20] Chen P,Guo L,Li J.Effects of homocysteine on nonalcoholic fatty liver related disease: a mendelian randomization study.Front Mol Biosci2022;9:1083855 PMCID:PMC9763576

[21] Lonardo A,Ballestri S.Sex differences in nonalcoholic fatty liver disease: state of the art and identification of research gaps.Hepatology2019;70:1457-69 PMCID:PMC6766425

[22] Meigs JB,Selhub J.Framingham Offspring StudyFasting plasma homocysteine levels in the insulin resistance syndrome: the Framingham offspring study.Diabetes Care2001;24:1403-10