Lifestyle intervention modifies the effect of the MC4R genotype on changes in insulin resistance among women with prior gestational diabetes: Tianjin Gestational Diabetes Mellitus Prevention Program

Genetic and inflammatory factors underlying gestational diabetes mellitus: a review

Gestational diabetes mellitus (GDM) poses a significant global health concern, impacting both maternal and fetal well-being. Early detection and treatment are imperative to mitigate adverse outcomes during pregnancy. This review delves into the pivotal role of insulin function and the influence of genetic variants, including SLC30A8, CDKAL1, TCF7L2, IRS1, and GCK, in GDM development. These genetic variations affect beta-cell function and insulin activity in crucial tissues, such as muscle, disrupting glucose regulation during pregnancy. We propose a hypothesis that this variation may disrupt zinc transport, consequently impairing insulin production and secretion, thereby contributing to GDM onset. Furthermore, we discussed the involvement of inflammatory pathways, such as TNF-alpha and IL-6, in predisposing individuals to GDM. Genetic modulation of these pathways may exacerbate glucose metabolism dysregulation observed in GDM patients. We also discussed how GDM affects cardiovascular disease (CVD) through a direct correlation between pregnancy and cardiometabolic function, increasing atherosclerosis, decreased vascular function, dyslipidemia, and hypertension in women with GDM history. However, further research is imperative to unravel the intricate interplay between inflammatory pathways, genetics, and GDM. This understanding is pivotal for devising targeted gene therapies and pharmacological interventions to rectify genetic variations in SLC30A8, CDKAL1, TCF7L2, IRS1, GCK, and other pertinent genes. Ultimately, this review offers insights into the pathophysiological mechanisms of GDM, providing a foundation for developing strategies to mitigate its impact.

Genetic risk of type 2 diabetes modifies the association between lifestyle and glycemic health at 5 years postpartum among high-risk women

INTRODUCTION

Lifestyle interventions are effective in preventing type 2 diabetes, but genetic background may influence the individual response. In the Finnish gestational diabetes prevention study, RADIEL, lifestyle intervention during pregnancy and first postpartum year was effective in preventing gestational diabetes (GDM) and postpartum glycemic abnormalities only among women at highest genetic risk of type 2 diabetes. This study aimed to assess whether still 5 years postpartum the genetic risk modifies the association between lifestyle and glycemic health.

RESEARCH DESIGN AND METHODS

The RADIEL study (randomized controlled trial) aimed to prevent GDM with a lifestyle intervention among high-risk women (body mass index ≥30 kg/m2 and/or prior GDM). The follow-up study 5 years postpartum included anthropometric measurements, laboratory assessments, device-measured physical activity (PA), and questionnaires. A Healthy Lifestyle Score (HLS) indicated adherence to lifestyle goals (PA, diet, smoking) and a polygenic risk score (PRS) based on 50 type 2 diabetes risk alleles depicted the genetic risk.

RESULTS

Altogether 314 women provided genetic and glycemic data 5 years postpartum. The PRS for type 2 diabetes was not associated with glycemic abnormalities, nor was HLS in the total study sample. There was, however, an interaction between HLS and type 2 diabetes PRS on glycemic abnormalities (p=0.03). When assessing the association between HLS and glycemic abnormalities in PRS tertiles, HLS was associated with reduced risk of glycemic abnormalities only among women at the highest genetic risk (p=0.008).

CONCLUSIONS

These results extend our previous findings from pregnancy and first postpartum year demonstrating that still at 5 years postpartum, healthy lifestyle is associated with a lower risk of prediabetes/diabetes only among women at the highest genetic risk of type 2 diabetes.

Gestational diabetes mellitus: genetic factors, epigenetic alterations, and microbial composition

Gestational diabetes mellitus (GDM) is a common metabolic disorder, usually diagnosed during the third trimester of pregnancy that usually disappears after delivery. In GDM, the excess of glucose, fatty acids, and amino acids results in foetuses large for gestational age. Hyperglycaemia and insulin resistance accelerate the metabolism, raising the oxygen demand, and creating chronic hypoxia and inflammation. Women who experienced GDM and their offspring are at risk of developing type-2 diabetes, obesity, and other metabolic or cardiovascular conditions later in life. Genetic factors may predispose the development of GDM; however, they do not account for all GDM cases; lifestyle and diet also play important roles in GDM development by modulating epigenetic signatures and the body's microbial composition; therefore, this is a condition with a complex, multifactorial aetiology. In this context, we revised published reports describing GDM-associated single-nucleotide polymorphisms (SNPs), DNA methylation and microRNA expression in different tissues (such as placenta, umbilical cord, adipose tissue, and peripheral blood), and microbial composition in the gut, oral cavity, and vagina from pregnant women with GDM, as well as the bacterial composition of the offspring. Altogether, these reports indicate that a number of SNPs are associated to GDM phenotypes and may predispose the development of the disease. However, extrinsic factors (lifestyle, nutrition) modulate, through epigenetic mechanisms, the risk of developing the disease, and some association exists between the microbial composition with GDM in an organ-specific manner. Genes, epigenetic signatures, and microbiota could be transferred to the offspring, increasing the possibility of developing chronic degenerative conditions through postnatal life.

Integration of methylation quantitative trait loci (mQTL) on dietary intake on DNA methylation levels: an example of n-3 PUFA and ABCA1 gene

BACKGROUND

Epigenetic studies have reported relationships between dietary nutrient intake and methylation levels. However, genetic variants that may affect DNA methylation (DNAm) pattern, called methylation quantitative loci (mQTL), are usually overlooked in these analyses. We investigated whether mQTL change the relationship between dietary nutrient intake and leukocyte DNAm levels with an example of estimated fatty acid intake and ATP-binding cassette transporter A1 (ABCA1).

METHODS

A cross-sectional study on 231 participants (108 men, mean age: 62.7 y) without clinical history of cancer and no prescriptions for dyslipidemia. We measured leukocyte DNAm levels of 8 CpG sites within ABCA1 gene by pyrosequencing method and used mean methylation levels for statistical analysis. TaqMan assay was used for genotyping a genetic variant of ABCA1 (rs1800976). Dietary fatty acid intake was estimated with a validated food frequency questionnaire and adjusted for total energy intake by using residual methods.

RESULTS

Mean ABCA1 DNAm levels were 5% lower with the number of minor alleles in rs1800976 (CC, 40.6%; CG, 35.9%; GG, 30.6%). Higher dietary n-3 PUFA intake was associated with lower ABCA1 DNAm levels (1st (ref) vs. 4th, β [95% CI]: -2.52 [-4.77, -0.28]). After controlling for rs180076, the association between dietary n-3 PUFA intake and ABCA1 DNAm levels was attenuated, but still showed an independent association (1st (ref) vs. 4th, β [95% CI]: -2.00 [-3.84, -0.18]). The interaction of mQTL and dietary n-3 PUFA intake on DNAm levels was not significant.

CONCLUSIONS

This result suggested that dietary n-3 PUFA intake would be an independent predictor of DNAm levels in ABCA1 gene after adjusting for individual genetic background. Considering mQTL need to broaden into other genes and nutrients for deeper understanding of DNA methylation, which can contribute to personalized nutritional intervention.

The interaction between MC4R gene variant (rs17782313) and dominant dietary patterns on depression in obese and overweight women: a cross sectional study

BACKGROUND

Previous studies have shown that the minor allele (C allele) for melanocortin 4 receptor (MC4R) rs17782313 may be associated with depressed mood. Moreover, dietary patterns have potentially adverse effects on depression. This study investigates the interactions between the MC4R gene variant (rs17782313) and dietary patterns on depression among Iranian obese and overweight women.

METHODS

A total of 289 Iranian overweight and obese women, aged 18-50 years, were enrolled in this cross-sectional study. Biochemical, anthropometric, and body composition indices were assessed in all participants. Moreover, MC4R rs17782313, by the restriction fragment length polymorphism (PCR-RFLP) method, and depression, using the 21-item Depression Anxiety Stress Scales (DASS) questionnaire, were assessed. Food intakes were assessed by completing a 147-item semi-quantitative food frequency questionnaire (FFQ).

RESULTS

By the use of factor analysis, 2 major dietary patterns were extracted: healthy dietary pattern (HDP) and unhealthy dietary pattern (UDP). Binary logistic analysis showed that individuals with minor allele risk (CC) with high adherence to the unhealthy pattern increased odds for depression (OR: 8.77, 95%CI: -0.86-18.40, P: 0.07), after controlling for confounders. Also, a logical inverse relationship was observed between CT genotype and HDP on depression in the crude and adjusted models (OR: -0.56, 95% CI: -3.69-2.57, P: 0.72) (OR: -4.17, 95% CI: -9.28-0.94, P: 0.11), although this interaction was not statistically significant.

CONCLUSION

According to the above findings, adherence to unhealthy food intake pattern increases odds of depression in MC4R risk allele (C allele) carriers. To confirm these findings, more studies are needed in the form of clinical trials and prospective studies with higher sample sizes.

The genetic risk of gestational diabetes in South Asian women

South Asian women are at increased risk of developing gestational diabetes mellitus (GDM). Few studies have investigated the genetic contributions to GDM risk. We investigated the association of a type 2 diabetes (T2D) polygenic risk score (PRS), on its own, and with GDM risk factors, on GDM-related traits using data from two birth cohorts in which South Asian women were enrolled during pregnancy. 837 and 4372 pregnant South Asian women from the SouTh Asian BiRth CohorT (START) and Born in Bradford (BiB) cohort studies underwent a 75-g glucose tolerance test. PRSs were derived using genome-wide association study results from an independent multi-ethnic study (~18% South Asians). Associations with fasting plasma glucose (FPG); 2 hr post-load glucose (2hG); area under the curve glucose; and GDM were tested using linear and logistic regressions. The population attributable fraction (PAF) of the PRS was calculated. Every 1 SD increase in the PRS was associated with a 0.085 mmol/L increase in FPG ([95% confidence interval, CI=0.07-0.10], p=2.85×10^-20); 0.21 mmol/L increase in 2hG ([95% CI=0.16-0.26], p=5.49×10^-16); and a 45% increase in the risk of GDM ([95% CI=32-60%], p=2.27×10^-14), independent of parental history of diabetes and other GDM risk factors. PRS tertile 3 accounted for 12.5% of the population's GDM alone, and 21.7% when combined with family history. A few weak PRS and GDM risk factors interactions modulating FPG and GDM were observed. Taken together, these results show that a T2D PRS and family history of diabetes are strongly and independently associated with multiple GDM-related traits in women of South Asian descent, an effect that could be modulated by other environmental factors.

Genetic Risk Factors and Gene-Lifestyle Interactions in Gestational Diabetes

Paralleling the increasing trends of maternal obesity, gestational diabetes (GDM) has become a global health challenge with significant public health repercussions. In addition to short-term adverse outcomes, such as hypertensive pregnancy disorders and fetal macrosomia, in the long term, GDM results in excess cardiometabolic morbidity in both the mother and child. Recent data suggest that women with GDM are characterized by notable phenotypic and genotypic heterogeneity and that frequencies of adverse obstetric and perinatal outcomes are different between physiologic GDM subtypes. However, as of yet, GDM treatment protocols do not differentiate between these subtypes. Mapping the genetic architecture of GDM, as well as accurate phenotypic and genotypic definitions of GDM, could potentially help in the individualization of GDM treatment and assessment of long-term prognoses. In this narrative review, we outline recent studies exploring genetic risk factors of GDM and later type 2 diabetes (T2D) in women with prior GDM. Further, we discuss the current evidence on gene-lifestyle interactions in the development of these diseases. In addition, we point out specific research gaps that still need to be addressed to better understand the complex genetic and metabolic crosstalk within the mother-placenta-fetus triad that contributes to hyperglycemia in pregnancy.

Examining the effect of obesity-associated gene variants on breast cancer survivors in a randomized weight loss intervention

PURPOSE

Our study examined whether common variants of obesity-associated genes FTO, MC4R, BDNF, and CREB1 moderated the effects of a lifestyle intervention on weight change among breast cancer survivors.

METHODS

151 breast cancer survivors with a body mass index ≥ 25 kg/m² were randomly assigned to a 6-month weight loss intervention or usual care group. Genotyping of FTO rs9939609, MC4R rs6567160, BDNF rs11030104, CREB1 rs17203016 was performed. Linear mixed models were used including the main effects of genotype (assuming a dominant genetic model), treatment arm on weight and percent body fat changes, and genotype by treatment interaction variable. All statistical tests were evaluated against a Bonferroni-corrected alpha of 0.0125.

RESULTS

Women in the intervention group achieved significantly greater weight loss than the usual care group (5.9% vs 0.4%, p < 0.001), regardless of genotype. Changes in weight and percent body fat did not differ significantly between carriers of the FTO rs9939609, MC4R rs6567160, BDNF rs11030104, and CREB1 rs17203016 risk alleles compared to non-carriers (p-interaction > 0.0125 for each single-nucleotide polymorphisms).

CONCLUSIONS

Women who are genetically predisposed to obesity and recently diagnosed with breast cancer may achieve significant and clinically meaningful weight loss through healthy eating and exercise.

CLINICAL TRIAL REGISTRATION

NCT02863887 (Date of Registration: August 11, 2016); NCT02110641 (Date of Registration: April 10, 2014).