Reduced glycodeoxycholic acid levels are associated with negative clinical outcomes of gestational diabetes mellitus

Profile of Serum Bile Acids in Elderly Type 2 Diabetic Patients with Various Obesity Types: A Cross-Sectional Study

Objective

The distribution of body fat plays a critical role in the pathogenesis of type 2 diabetes mellitus (T2DM). However, the specific metabolic profiles and biomarkers that distinguish the different obesity phenotypes in T2DM remain to be fully elucidated. Bile acids (BAs), which are recognized as pivotal signaling molecules in the regulation of glucose and lipid metabolism, warrant further investigation to characterize their profiles across different obesity phenotypes. Understanding the clinical significance of these BAs in the management of T2DM is essential and merits thorough exploration.

Design

In this cross-sectional study conducted at the Zhangjiang Community Health Service Center in Shanghai, ninety-nine elderly participants were recruited and categorized into four groups: non-diabetic controls (NC), T2DM with lean phenotype (TN), T2DM with overweight phenotype (TO), and T2DM with abdominal obesity phenotype (TA). Biochemical indices, visceral adiposity indices, and bile acid (BA) profiles were analyzed and compared across the groups.

Results

Healthy individuals exhibited lower triglyceride levels, waist-to-hip ratio (WHR), visceral adiposity index (VAI), and Chinese visceral adiposity index (CVAI), as well as higher HDL-c level and total BA levels compared to T2DM patients. T2DM patients with different obesity phenotypes displayed distinct BA profiles. Specifically, the TN group showed higher levels of conjugated DCA BA species, GDCA, and TDCA, compared to the TO group. These BA species are essential for regulating lipid and glucose metabolism. In contrast, the TA group exhibited higher ratios of 12α-hydroxylated BAs to non 12α-hydroxylated BAs, taurine-conjugated BAs to glycine-conjugated BAs, and higher levels of LCA compared to the TO group. Additionally, CVAI was positively associated with unconjugated SBAs, CA-7S, and DLCA.

Conclusion

These results revealed that T2DM patients with different obesity phenotypes exhibit distinct BA profiles. Specific BAs, particularly GDCA, TDCA, and LCA, are closely associated with adiposity indices and may serve as crucial signaling molecules in modulating visceral adiposity, serum lipid profiles, and glucose homeostasis in obese T2DM patients. These BA species play a pivotal role in the pathogenetic process underlying diabetes and various forms of obesity. Furthermore, their significance highlights their potential contributors to drug development and as therapeutic targets for T2DM patients with specific obesity subtypes.

The association of serum total bile acid levels with gestational diabetes mellitus: a systematic review and meta-analysis

BACKGROUND

Given the high prevalence of gestational diabetes mellitus and its significant impact on maternal and neonatal health, identifying reliable biomarkers for prediction and diagnosis is essential. The increased incidence of gestational diabetes mellitus among patients with intrahepatic cholestasis of pregnancy suggests a possible association between serum total bile acid levels and gestational diabetes mellitus. This study evaluated the relationship between total bile acid levels and gestational diabetes mellitus incidence.

METHODS

A systematic search was performed on February 19, 2024, for studies examining the association between total bile acid levels and gestational diabetes mellitus incidence in both the general pregnant population and patients diagnosed with intrahepatic cholestasis of pregnancy. Meta-analyses were conducted to compare pooled total bile acid levels between patients with and without gestational diabetes mellitus, as well as to assess gestational diabetes mellitus prevalence in patients with mild (10 ≤ total bile acid < 40 µmol/L) vs. moderate-to-severe intrahepatic cholestasis of pregnancy (total bile acid ≥ 40 µmol/L).

RESULTS

15 observational studies involving 7,238 pregnant women were systematically reviewed. Our meta-analysis found significantly higher serum total bile acid levels in women diagnosed with gestational diabetes mellitus compared to controls in the general population (Hedge's g = 0.29 [0.03,0.54]). However, subgroup analysis indicated that total bile acid levels were only significantly higher in patients measured earlier in pregnancy, before the gestational diabetes mellitus diagnosis, compared to healthy controls (Hedge's g = 0.48 [0.33,0.64]), while no significant difference in total bile acid levels was observed when measurements were taken after the gestational diabetes mellitus diagnosis (Hedge's g = 0.00 [-0.26,0.27]). Additionally, we found that the prevalence of gestational diabetes mellitus was significantly lower in patients with mild intrahepatic cholestasis of pregnancy compared to those with moderate-to-severe intrahepatic cholestasis of pregnancy (Log odds ratio=-0.56 [-0.95,-0.17]).

CONCLUSIONS

This study highlights a complex relationship between serum total bile acid levels and gestational diabetes mellitus incidence, influenced by the timing of measurement. Elevated total bile acid levels early in pregnancy may predict gestational diabetes mellitus, but its diagnostic value may decline later in pregnancy.

TRIAL REGISTRATION

The review protocol was registered in the International Prospective Register of Systematic Reviews (PROSPERO) on 3/3/2024 under CRD42024516164.

Serum bile acid measurements in women of European and South Asian ethnicity with or without gestational diabetes mellitus: A cohort study

OBJECTIVE

Investigation of serum bile acid profiles in pregnancies complicated by gestational diabetes mellitus (GDM) in a multi-ethnic cohort of women who are lean or obese.

DESIGN

Prospective cohort study.

SETTING

UK multicentre study.

POPULATION

Fasting serum from participants of European or South Asian self-reported ethnicity from the PRiDE study, between 23 and 31 weeks of gestation.

METHODS

Bile acids were measured using ultra-performance liquid chromatography-tandem mass spectrometry. Log-transformed data were analysed using linear regression in STATA/IC 15.0.

MAIN OUTCOME MEASURES

Total bile acids (TBAs), C4, fasting glucose and insulin.

RESULTS

The TBAs were 1.327-fold (1.105-1.594) increased with GDM in European women (P = 0.003). Women with GDM had 1.162-fold (1.002-1.347) increased levels of the BA synthesis marker C4 (P = 0.047). In South Asian women, obesity (but not GDM) increased TBAs 1.522-fold (1.193-1.942, P = 0.001). Obesity was associated with 1.420-fold (1.185-1.702) increased primary/secondary BA ratio (P < 0.001) related to 1.355-fold (1.140-1.611) increased primary BA concentrations (P = 0.001). TBAs were positively correlated with fasting glucose (P = 0.039) in all women, and with insulin (P = 0.001) and the Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) (P = 0.001) in women with GDM.

CONCLUSIONS

Serum BA homeostasis in late gestation depends on body mass index and GDM in ethnicity-specific ways. This suggests ethnicity-specific aetiologies may contribute to metabolic risk in European and South Asian women, with the relationship between BAs and insulin resistance of greater importance in European women. Further studies into ethnicity-specific precision medicine for GDM are required.

Ketogenic diet-induced bile acids protect against obesity through reduced calorie absorption

The low-carbohydrate ketogenic diet (KD) has long been practiced for weight loss, but the underlying mechanisms remain elusive. Gut microbiota and metabolites have been suggested to mediate the metabolic changes caused by KD consumption, although the particular gut microbes or metabolites involved are unclear. Here, we show that KD consumption enhances serum levels of taurodeoxycholic acid (TDCA) and tauroursodeoxycholic acid (TUDCA) in mice to decrease body weight and fasting glucose levels. Mechanistically, KD feeding decreases the abundance of a bile salt hydrolase (BSH)-coding gut bacterium, Lactobacillus murinus ASF361. The reduction of L. murinus ASF361 or inhibition of BSH activity increases the circulating levels of TDCA and TUDCA, thereby reducing energy absorption by inhibiting intestinal carbonic anhydrase 1 expression, which leads to weight loss. TDCA and TUDCA treatments have been found to protect against obesity and its complications in multiple mouse models. Additionally, the associations among the abovementioned bile acids, microbial BSH and metabolic traits were consistently observed both in an observational study of healthy human participants (n = 416) and in a low-carbohydrate KD interventional study of participants who were either overweight or with obesity (n = 25). In summary, we uncover a unique host-gut microbiota metabolic interaction mechanism for KD consumption to decrease body weight and fasting glucose levels. Our findings support TDCA and TUDCA as two promising drug candidates for obesity and its complications in addition to a KD.

Role of melatonin receptor 1B gene polymorphism and its effect on the regulation of glucose transport in gestational diabetes mellitus

Melatonin receptor 1B (MT2, encoded by the MTNR1B gene), a high-affinity receptor for melatonin, is associated with glucose homeostasis including glucose uptake and transport. The rs10830963 variant in the MTNR1B gene is linked to glucose metabolism disorders including gestational diabetes mellitus (GDM); however, the relationship between MT2-mediated melatonin signaling and a high birth weight of GDM infants from maternal glucose abnormality remains poorly understood. This article aims to investigate the relationship between rs10830963 variants and GDM development, as well as the effects of MT2 receptor on glucose uptake and transport in trophoblasts. TaqMan-MGB (minor groove binder) probe quantitative real-time polymerase chain reaction (qPCR) assays were used for rs10930963 genotyping. MT2 expression in the placenta of GDM and normal pregnant women was detected by immunofluorescence, western blot, and qPCR. The relationship between MT2 and glucose transporters (GLUTs) or peroxisome proliferator-activated receptor γ (PPARγ) was established by western blot, and glucose consumption of trophoblasts was measured by a glucose assay kit. The results showed that the genotype and allele frequencies of rs10830963 were significantly different between GDM and normal pregnant women (P<0.05). The fasting, 1-h and 2-h plasma glucose levels of G-allele carriers were significantly higher than those of C-allele carriers (P<0.05). Besides, the protein and messenger RNA (mRNA) expression of MT2 in the placenta of GDM was significantly higher than that of normal pregnant women (P<0.05). Melatonin could stimulate glucose uptake and GLUT4 and PPARγ protein expression in trophoblasts, which could be attenuated by MT2 receptor knockdown. In conclusion, the rs10830963 variant was associated with an increased risk of GDM. The MT2 receptor is essential for melatonin to raise glucose uptake and transport, which may be mediated by PPARγ.

Untargeted approach to investigating the metabolomics profile of type 2 diabetes emiratis

Type 2 Diabetes (T2D) is expected to be the seventh most significant cause of death worldwide by 2030. Although research into its mechanism has received the attention it deserves, our understanding of T2D is still limited. This case-control study employs untargeted metabolomics to explore novel T2D plasma biomarkers in the Emirati population. Ninety-two UAE nationals were included in the cohort, with fifty T2D and forty-two non-T2D profiles. Participants were then stratified into three groups based on metabolic profiles, clinically verified diabetic status, and current HbA1c values: namely controlled diabetics, uncontrolled diabetics and prediabetics, and non-diabetics. The study identified fifteen significant differentially abundant metabolites between the uncontrolled diabetics group and the prediabetics or controlled diabetics group. Interestingly, some metabolites essential for the corticosteroid and thyroid signaling pathways were found to be significantly elevated in poorly controlled T2D, including cortisol, glycocholic acid, bile acids, thyroxine, and the tryptophan metabolite, 5-hydroxyindoleacetic acid. These findings align with those from prior western cohorts and suggest an intriguing linkage between T2D glycemic control and thyroid and adrenal signaling that may provide new diagnostic and prognostic indicators. RESEARCH SIGNIFICANCE: This study investigates the underlooked metabolomic role and correlation with T2D in the UAE population. The report indicates fifteen significant differentially abundant metabolites between on diabetics, uncontrolled diabetics and or controlled diabetics or prediabetics. This panel of metabolites such as thyroxine and corticosteroids should be considered further as potential diagnostic or prognostic biomarkers for T2D in the region.

Predictive values of serum metabolites in early pregnancy and their possible pathways for gestational diabetes: A nested case-control study in Tianjin, China

AIMS

To investigate the associations and predictive values of serum metabolites in early pregnancy for later development of gestational diabetes mellitus (GDM), and further explore their metabolic pathways to GDM.

METHODS

We conducted a 1:1 nested case-control study including 486 pregnant women from Tianjin, China, and collected blood samples at their first registration (median at 10th gestational week). Liquid chromatography-tandem mass spectrometry was used to measure serum metabolites. Orthogonal partial least squares discriminant analysis was used to select specific metabolites associated with GDM, and pathway analysis was used to identify the metabolic pathways related to GDM.

RESULTS

A total of 64 serum metabolites were included in this analysis, 17 of which were identified as specific metabolites associated with GDM. Ten metabolites increased and seven metabolites decreased GDM risk. Inclusion of these specific metabolites to the model of traditional risk factors greatly increased the predictive value from 0.69 (95% confidence interval: 0.64-0.74) to 0.92 (0.90-0.95). In addition, we found that glycerophospholipid metabolism, sphingolipid metabolism and primary bile acid biosynthesis were main metabolic pathways related to GDM.

CONCLUSION

We identified a set of serum metabolites and their metabolic pathways in early pregnancy associated with GDM, which provided a theoretical basis for further research on the molecular pathways to GDM and early identification of GDM.

First trimester metabolomics 1H-NMR study of the urinary profile predicts gestational diabetes mellitus development in obese women

OBJECTIVE

Obesity is one of the main risk factors for the development gestational diabetes mellitus (GDM). Thus, we aim to identify changes in the urinary metabolomics profile of obese women at first trimester of pregnancy in order to predict later GDM diagnosis.

RESEARCH DESIGN AND METHODS

In this nested case-control study, urine samples collected in the first trimester of pregnancy obtained from obese women who developed GDM (n = 29) and obese women who did not develop diabetes (n = 25 NO GDM) were analyzed with Nuclear Magnetic Resonance spectroscopy combined with Multivariate Statistical Analysis. GDM diagnosis was obtained with one-step oral glucose load.

RESULTS

OPLS-DA significantly separated the GDM women from NO GDM women. Specifically, GDM women were characterized by a higher level of tryptophan, trigonelline, hippurate, and threonine, and lower levels of 1-methylnicotinamide, 3-hydroxykynurenine, glycocholate, isoleucine, kynurenine, and valine compared to NO GDM women.

CONCLUSION

In a prevalently Caucasian population, the changes of some metabolites such as tryptophan, trigonelline, and branch-chained amino acids in the urinary profile of obese women in the first trimester are able to make unequivocal prediction of those which later test positive for GDM. This approach could be useful to diagnose much earlier obese women with GDM allowing lifestyle counselling and other interventions.