The genetic and epigenetic basis of type 2 diabetes and obesity

Impact of age on cardiometabolic health in children at adiposity rebound: the role of genetic mechanisms

BACKGROUND

Identifying effective predictors early in life is crucial to enable timely prevention and intervention to improve cardiometabolic health outcomes. Adiposity rebound (AR) is an important period in early life, with earlier AR increasing the risk of cardiometabolic abnormalities. However, the role and mechanism of genetic factors in this association are unclear. Therefore, this study reviews the potential genetic mechanisms influencing the age at AR, as well as the genetic mechanisms linking earlier AR with cardiometabolic abnormalities.

DATA SOURCES

A comprehensive literature search was conducted in PubMed and China National Knowledge Infrastructure databases using a combination of medical subject headings terms and related keywords, including "adiposity rebound", "cardiometabolic", "obesity", "BMI trajectory", "diabetes mellitus", "dyslipidemias", "hypertension", "metabolic syndrome", "genetics", and "epigenetic". Citation tracking was performed as a supplementary search strategy. All potentially relevant articles were subsequently subjected to full-text evaluation for eligibility assessment.

RESULTS

Polymorphisms in the DMRT1, FTO, LEPR, and TFAP2B genes, along with obesity susceptibility, can influence the age at AR. Single-nucleotide polymorphisms associated with the age at AR are enriched in the insulin-like growth factor 1 (IGF-1) signaling pathway, which can be modulated by the LEPR and TFAP2B genes. Shared genetic mechanisms between cardiometabolic abnormalities and the age at AR are influenced by obesity-related genetic variants. These variants regulate the growth hormone (GH)/IGF-1 axis, advancing AR and leading to cardiometabolic abnormalities. Earlier AR alters adiponectin and leptin levels, further activating the GH/IGF-1 axis and creating a vicious cycle. Long-term breastfeeding can counteract the adverse effects of obesity-related genetic susceptibility on AR timing, thereby reducing the genetic risk of cardiometabolic abnormalities.

CONCLUSIONS

Our results support earlier AR as a marker for identifying cardiometabolic risk and screening high-risk populations at the genetic level.

DNA methylation signatures of youth-onset type 2 diabetes and exposure to maternal diabetes

OBJECTIVE

Youth-onset type 2 diabetes (T2D) is physiologically distinct from adult-onset, but it is not clear how the two diseases differ at a molecular level. In utero exposure to maternal type 2 diabetes (T2D) is known to be a specific risk factor for youth-onset T2D. DNA methylation (DNAm) changes associated with T2D but which differ between youth- and adult-onset might delineate the impacts of T2D development at different ages and could also determine the contribution of exposure to in utero diabetes.

METHODS

We performed an epigenome-wide analysis of DNAm on whole blood from 218 youth with T2D and 77 normoglycemic controls from the iCARE (improving renal Complications in Adolescents with type 2 diabetes through REsearch) cohort. Associations were tested using multiple linear regression models while adjusting for maternal diabetes, sex, age, BMI, smoking status, second-hand smoking exposure, cell-type proportions and genetic ancestry.

RESULTS

We identified 3830 differentially methylated sites associated with youth T2D onset, of which 3794 were moderately (adjusted p-value < 0.05 and effect size estimate > 0.01) associated and 36 were strongly (adjusted p-value < 0.05 and effect size estimate > 0.05) associated. A total of 3725 of these sites were not previously reported in the EWAS Atlas as associated with T2D, adult obesity or youth obesity. Moreover, three CpGs associated with youth-onset T2D in the PFKFB3 gene were also associated with maternal T2D exposure (FDR < 0.05 and effect size > 0.01). This is the first study to link PFKFB3 and T2D in youth.

CONCLUSION

Our findings support that T2D in youth has different impacts on DNAm than adult-onset, and suggests that changes in DNAm could provide an important link between in utero exposure to maternal diabetes and the onset of T2D.

Assessment of liver enzymes as diagnostic biomarkers in type 2 diabetes mellitus: a cross-sectional study in Zakho, Iraq

BACKGROUND

This study aimed to identify the prevalence and factors associated with abnormal liver enzyme profiles in individuals with type 2 diabetes (T2D) in Zakho, to assess the association between demographic characteristics, clinical parameters, kidney function tests, lipid profiles, glucose levels, and T2D, and to identify resident risk factors.

RESEARCH DESIGN AND METHODS

A cross-sectional analysis of T2D patients admitted to Zakho General Hospital was conducted utilizing hospital records. The primary endpoint of interest was attaining HbA1C levels ≥ 6.5%. Analytical methodologies encompassed linear and multivariate logistic regression analyses, with due consideration of the association between diverse parameters and glycemic alterations. Further, the predictive value of biomarkers was evaluated through Receiver Operating Characteristic (ROC) curves and Area Under the Curve (AUC) analyses, complemented by Spearman correlation analysis to explore relationships among laboratory parameters.

RESULTS

The study found that 89.4% of participants had HbA1C levels above 6.5%, with a preference for T2D among older individuals (mean age: 52.93-49.89 respectively) and females. Age, glucose levels, and liver enzymes positively correlated with HbA1C.

CONCLUSIONS

The study emphasizes the diagnostic importance of liver enzymes in individuals with type 2 diabetes, suggesting that these biomarkers could be valuable indicators of disease severity and progression.

Long-term PM2.5 exposure and early-onset diabetes: Does BMI link this risk?

OBJECTIVE

Limited studies investigated the association between high-level fine particulate matter (PM2.5) pollution and early-onset diabetes, leaving the possible metabolic mechanisms unclear. We assessed the association of cumulative PM2.5 exposure with diabetes, including early-onset, in high-pollution areas of China and explored whether metabolic factors mediated this association.

METHODS

124,204 participants (≥18 years) from 121 counties in Hunan province, China, were enrolled between 2005 and 2020, with follow-up until 2021. The ground-level air pollution concentrations at each participant's residence were calculated using a high-quality dataset in China. The independent association of PM2.5 with incident diabetes and early-onset diabetes was assessed by Cox proportional hazards models. Restricted cubic splines were utilized to establish the exposure-response relationships. The role of metabolism-related mediators was estimated by mediation analysis.

RESULTS

During a median follow-up of 8.47 (IQR, 6.65-9.82) years, there were 3650 patients with new-onset diabetes. Each 1 μg/m3 increase in the level of cumulative PM2.5 exposure was positively related to an increased incidence of diabetes (HR 1.177, 95 % CI 1.172-1.181) among individuals in the PM2.5 > 50 μg/m3 group after adjusting for multiple variables. The relationship of the PM2.5 dose-response curve for diabetes was non-linear. Significant associations between PM2.5 exposure and early-onset diabetes risk were observed, with this risk showing an increase with the earlier age of early diabetes onset. Males, young individuals (≤45 years), and those with a lower body mass index (BMI <24 kg/m2) appeared to be more susceptible to diabetes. Moreover, change in BMI significantly mediated 31.06 % of the PM2.5-diabetes relationship.

CONCLUSIONS

Long-term cumulative PM2.5 exposure increased the risk of early-onset diabetes, which is partially mediated by BMI. Sustained air pollution control measures, priority protection of vulnerable individuals, and effective management of BMI should be taken to reduce the burden of diabetes.

Chia seeds ameliorate cardiac disease risk factors via alleviating oxidative stress and inflammation in rats fed high-fat diet

Obesity upsurges the risk of developing cardiovascular disease, primarily heart failure and coronary heart disease. Chia seeds have a high concentration of dietary fiber and increased concentrations of anti-inflammatoryand antioxidant compounds. They are used for weight loss plus enhancing blood glucose and lipid profile. The current perspective was commenced to examine the protective influence of chia seeds ingestion on cardiovascular disease risk factors in high-fat diet-fed rats. Forty male albino rats (with an initial body weight of 180-200 g) were used in this study. Rats were randomly and equally divided into 4 groups: Group I was the control group and group II was a control group with chia seeds supplementation. Group III was a high-fat diet group (HFD) that received HFD for 10 weeks and group IV was fed on HFD plus chia seeds for 10 weeks. In all groups Echocardiographic measurements were performed, initial and final BMI, serum glucose, AC/TC ratio, lipid profile, insulin (with a computed HOMA-IR), creatinine phosphokinase-muscle/brain (CPK-MB), CRP, and cardiac troponin I (cTnI) and MAP were estimated. Whole heart weight (WHW) was calculated, and then WHW/body weight (BW) ratio was estimated. Eventually, a histopathological picture of cardiac tissues was performed to assess the changes in the structure of the heart under Haematoxylin and Eosin and Crossmon's trichrome stain. Ingestion of a high diet for 10 weeks induced a clear elevation in BMI, AC/ TC, insulin resistance, hyperlipidemia, CRP, CPK-MB, and cTnI in all HFD groups. Moreover, there was a significant increase in MAP, left ventricular end diastolic diameter (LVEDD), and left ventricular end systolic diameter (LVESD). Furthermore, histological cardiac examination showed structural alteration of the normal structure of the heart tissue with an increase in collagen deposition. Also, the Bcl-2 expression in the heart muscle was significantly lower, but Bax expression was significantly higher. Chia seeds ingestion combined with HFD noticeably ameliorated the previously-recorded biochemical biomarkers, hemodynamic and echocardiography measures, and histopathological changes. Outcomes of this report reveal that obesity is a hazard factor for cardiovascular disease and chia seeds could be a good candidate for cardiovascular system protection.

Excessive weight gain onset-age and risk of developing diabetes mellitus: a large, prospective Chinese cohort study

Background

Excessive weight gain and obesity are widely accepted as risk factors for diabetes mellitus, and the age at which obesity onsets may be related to the development of cardiovascular diseases and certain cancers. Here, we aimed to investigate associations between the onset-age of overweight/obesity and risk of developing diabetes mellitus in China.

Methods

42,144 people with the normal weight range and without diabetes at baseline, were enrolled from the Kailuan cohort which began on the 1st June 2006. All participants were followed-up, biennially, until 31st December 2017. During follow-up, 11,220 participants had become overweight/obese. For each case, one normal-weight control was matched according to age ( ± 1 year) and sex. Our final analysis included 10,858 case-control pairs. An age-scaled Cox model was implemented to estimate hazard ratios (HR) with corresponding 95% confidence intervals (CI) for diabetes mellitus incidence across age-groups.

Results

At a median follow-up of 5.46 years, 1,403 cases of diabetes mellitus were identified. After multivariate adjustments, age-scaled Cox modelling suggested that risk gradually attenuated with every 10 year increase in age of onset of overweight/obesity. Diabetes mellitus adjusted HRs (aHRs) for new-onset overweight/obesity at <45years, 45-54 years, and 55-64 years were 1.47 (95%CI, 1.12-1.93), 1.38 (95%CI, 1.13-1.68), 1.32 (95%CI, 1.09-1.59), respectively. However, new-onset of overweight/obesity at ≥65 years did not relate to diabetes mellitus (aHR, 1.20; 95%CI, 0.92-1.57). This trend was not observed in women or the new-onset obesity subgroup but was evident in men and the new overweight onset subgroup.

Conclusion

Participants with early onset of excessive weight gain issues are at considerably higher risk of developing diabetes mellitus compared to those who maintain a normal weight.

Gene-environment interactions and the case of body mass index and obesity: How much do they matter?

We investigate the demographic and population health implications of gene-environment interactions (GxE) in the case of body mass index (BMI) and obesity. We seek to answer two questions: (a) what is the first-order impact of GxE effects on BMI and probability of obesity, e.g. the direct causal effect of G in different E's? and (b) how large is the impact of GxE effects on second-order health outcomes associated with BMI and obesity, such as type 2 diabetes (T2D) and disability? In contrast to most of the literature that focuses on estimating GxE effects, we study the implications of GxE effects for population health outcomes that are downstream of a causal chain that includes the target phenotype (in this case BMI) as the initial cause. To limit the scope of the paper, we focus on environments defined by birth cohorts. However, extensions to other environments (education, socioeconomic status (SES), early conditions, and physical settings) are straightforward.

Nutrient regulation of the islet epigenome controls adaptive insulin secretion

Adaptation of the islet β cell insulin-secretory response to changing insulin demand is critical for blood glucose homeostasis, yet the mechanisms underlying this adaptation are unknown. Here, we have shown that nutrient-stimulated histone acetylation plays a key role in adapting insulin secretion through regulation of genes involved in β cell nutrient sensing and metabolism. Nutrient regulation of the epigenome occurred at sites occupied by the chromatin-modifying enzyme lysine-specific demethylase 1 (Lsd1) in islets. β Cell-specific deletion of Lsd1 led to insulin hypersecretion, aberrant expression of nutrient-response genes, and histone hyperacetylation. Islets from mice adapted to chronically increased insulin demand exhibited shared epigenetic and transcriptional changes. Moreover, we found that genetic variants associated with type 2 diabetes were enriched at LSD1-bound sites in human islets, suggesting that interpretation of nutrient signals is genetically determined and clinically relevant. Overall, these studies revealed that adaptive insulin secretion involves Lsd1-mediated coupling of nutrient state to regulation of the islet epigenome.

Epigenetics: Novel crucial approach for osteogenesis of mesenchymal stem cells

Bone has a robust regenerative potential, but its capacity to repair critical-sized bone defects is limited. In recent years, stem cells have attracted significant interest for their potential in tissue engineering. Applying mesenchymal stem cells (MSCs) for enhancing bone regeneration is a promising therapeutic strategy. However, maintaining optimal cell efficacy or viability of MSCs is limited by several factors. Epigenetic modification can cause changes in gene expression levels without changing its sequence, mainly including nucleic acids methylation, histone modification, and non-coding RNAs. This modification is believed to be one of the determinants of MSCs fate and differentiation. Understanding the epigenetic modification of MSCs can improve the activity and function of stem cells. This review summarizes recent advances in the epigenetic mechanisms of MSCs differentiation into osteoblast lineages. We expound that epigenetic modification of MSCs can be harnessed to treat bone defects and promote bone regeneration, providing potential therapeutic targets for bone-related diseases.

Role of DNA methylation in diabetes and obesity

Due to the fact that the upward trend of several metabolic disorders such as diabetes and obesity, in individuals especially monozygotic twins, who are under the same effects from the environment, are not similar, the role of epigenetic elements like DNA methylation needs taking into account. In this chapter, emerging scientific evidence supporting the strong relationship between changes in DNA methylation and those diseases' development was summarized. Changing in the expression level of diabetes/obesity-related genes through being silenced by methylation can be the underlying mechanism of this phenomenon. Genes with abnormal methylation status are potential biomarkers for early prediction and diagnosis. Moreover, methylation-based molecular targets should be investigated as a new treatment for both T2D and obesity.

Does crime trigger genetic risk for type 2 diabetes in young adults? A G x E interaction study using national data

BACKGROUND

Living in neighborhoods perceived as disordered exacerbates genetic risk for type 2 diabetes (T2D) among older adults. It is unknown whether this gene-neighborhood interaction extends to younger adults. The present study aims to investigate whether crime, an objectively measured indicator of neighborhood disorder, triggers genetic risk for T2D among younger adults, and whether this hypothesized triggering occurs through exposure to obesity.

METHODS

Data were from the Wave I (2008) National Longitudinal Study of Adolescent to Adult Health. A standardized T2D polygenic score was created using 2014 GWAS meta-analysis results. Weighted mediation analyses using generalized structural equation models were conducted in a final sample of 7606 adults (age range: 25-34) to test the overall association of T2D polygenic scores with T2D, and the mediating path through obesity exposure in low, moderate, and high county crime-rate groups. Age, sex, ancestry, educational degree, household income, five genetic principal components, and county-level concentrated advantage and population density were adjusted.

RESULTS

The overall association between T2D polygenic score and T2D was not significant in low-crime areas (p = 0.453), marginally significant in moderate-crime areas (p = 0.064), and statistically significant in high-crime areas (p = 0.007). The mediating path through obesity was not significant in low or moderate crime areas (ps = 0.560 and 0.261, respectively), but was statistically significant in high-crime areas (p = 0.023). The indirect path through obesity accounted for 12% of the overall association in high-crime area.

CONCLUSION

A gene-crime interaction in T2D was observed among younger adults, and this association was partially explained by exposure to obesity.

Integrated analysis of probability of type 2 diabetes mellitus with polymorphisms and methylation of SLC30A8 gene: a nested case-control study

To estimate the associations between single-nucleotide polymorphisms (SNPs) and methylation of SLC30A8 gene and T2DM risk, and the interactions among SNPs, methylation, and environmental factors on T2DM risk. We genotyped 9 SNPs and tested methylation at 46 CpG loci of SLC30A8 in the baseline DNA of 290 T2DM cases and 290 matched controls nested in the Rural Chinese Cohort Study. A conditional logistic regression model was used to estimate the associations between SNPs and SLC30A8 methylation and T2DM risk. Multifactor Dimensionality Reduction analysis was used to estimate the effect of interactions among SNPs, methylation, and environment on T2DM risk. Probability of T2DM was decreased with rs11558471 (GG vs. AA, OR = 0.55, 95% CI 0.32, 0.96), with rs13266634 (TT vs. CC, OR = 0.55, 95% CI 0.32, 0.94), with rs3802177 (AA vs. GG, OR = 0.54, 95%CI 0.31, 0.94), and its probability was increased with rs2466293 of SLC30A8 (GA vs. AA, OR = 1.63, 95% CI 1.08-2.47). Its probability was also significantly associated with methylation of CG9 and CG45 (OR = 0.56 [95% CI 0.33-0.97] and 1.61 [95%CI 1.03--2.51]). T2DM probability was significantly associated with the interaction effect between rs2466293 and hypertension (p = 0.045). T2DM probability was also significantly associated with the combination effects of rs2466293 with BMI, hypertension, and hypertriglyceridemia, with the combination effects of hypertriglyceridemia with rs11558471, rs13266634, and methylation of CG45.

Advancing Diabetes Prevention and Control in American Indians and Alaska Natives

As with many Indigenous populations globally, American Indians and Alaska Natives (AI/ANs) experience high rates of type 2 diabetes. Prevention efforts, ongoing medical care, patient self-management education, and support to prevent and reduce the risk of long-term complications must be developed to limit the impact of diabetes on individuals, families, and communities. Diabetes prevention and control require both individual- and community-level efforts as well as policies that attempt to mitigate contributing adverse socioeconomic factors. Congressional funding since 1998 continues to address the epidemic of diabetes in AI/AN groups with the Special Diabetes Program for Indians (SDPI), which has resulted in significant outcomes and key lessons that can inform new efforts to prevent diabetes in other populations and communities. The purpose of this review is to understand the context behind the epidemic of diabetes in AI/ANs, review the impact of the SDPI on prevention and control of diabetes as well as the translation of these strategies into clinical practice and their influence on health practice, and identify lessons learned for future efforts to address this ongoing challenge for AI/AN and other communities suffering from type 2 diabetes.

Interaction between a diabetes-related methylation site (TXNIP cg19693031) and variant (GLUT1 rs841853) on fasting blood glucose levels among non-diabetics

Background

Type 2 diabetes mellitus (T2DM) is caused by a combination of environmental, genetic, and epigenetic factors including, fasting blood glucose (FBG), genetic variant rs841853, and cg19693031 methylation. We evaluated the interaction between rs841853 and cg19693031 on the FBG levels of non-diabetic Taiwanese adults.

Methods

We used Taiwan Biobank (TWB) data collected between 2008 and 2016. The TWB data source contains information on basic demographics, personal lifestyles, medical history, methylation, and genotype. The study participants included 1300 people with DNA methylation data. The association of cg19693031 methylation (stratified into quartiles) with rs841853 and FBG was determined using multiple linear regression analysis. The beta-coefficients (β) and p-values were estimated.

Results

The mean ± standard deviation (SD) of FBG in rs841853-CC individuals (92.07 ± 7.78) did not differ significantly from that in the CA + AA individuals (91.62 ± 7.14). However, the cg19693031 methylation levels were significantly different in the two groups (0.7716 ± 0.05 in CC individuals and 0.7631 ± 0.05 in CA + AA individuals (p = 0.002). The cg19693031 methylation levels according to quartiles were β < 0.738592 (< Q1), 0.738592 ≤ 0.769992 (Q1–Q2), 0.769992 ≤ 0.800918 (Q2–Q3), and β ≥ 0.800918 (≥ Q3). FBG increased with decreasing cg19693031 methylation levels in a dose–response manner (p_trend = 0.005). The β-coefficient was − 0.0236 (p = 0.965) for Q2–Q3, 1.0317 (p = 0.058) for Q1–Q2, and 1.3336 (p = 0.019 for < Q1 compared to the reference quartile (≥ Q3). The genetic variant rs841853 was not significantly associated with FBG. However, its interaction with cg19693031 methylation was significant (p-value = 0.036). Based on stratification by rs841853 genotypes, only the CC group retained the inverse and dose–response association between FBG and cg19693031 methylation. The β (p-value) was 0.8082 (0.255) for Q2–Q3, 1.6930 (0.022) for Q1–Q2, and 2.2190 (0.004) for < Q1 compared to the reference quartile (≥ Q3). The p_trend was 0.002.

Conclusion

Summarily, methylation at cg19693031 was inversely associated with fasting blood glucose in a dose-dependent manner. The inverse association was more prominent in rs841853-CC individuals, suggesting that rs841853 could modulate the association between cg19693031 methylation and FBG. Our results suggest that genetic variants may be involved in epigenetic mechanisms associated with FBG, a hallmark of diabetes. Therefore, integrating genetic and epigenetic data may provide more insight into the early-onset of diabetes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03269-y.

GPR61 methylation in cord blood: a potential target of prenatal exposure to air pollutants

To explore the impact of air pollutants exposure during pregnancy on infant DNA methylation, we identified correlated methylated genes in maternal and cord blood samples using the Illumina Human Methylation 27 k BeadChip. Quantitative methylation-specific PCR (QMS-PCR) was performed to validate the target gene methylation pattern in 568 participants. Then the association between air pollutants exposure and DNA methylation level in the target gene was investigated. The GPR61 gene with a higher methylation level both in mothers and newborns was identified as the target gene, and we found a positive mother-infant DNA methylation correlation in the promoter region of GPR61. Air pollutants exposure during entire pregnancy was associated with maternal and infant GPR61 DNA methylation. After adjusting confounding variables, maternal air pollutants exposure was still associated with infant GPR61 DNA methylation. In summary, GPR61 methylation in cord blood may be a potential target of prenatal exposure to air pollutants.

Expression and methylation status of BTG2, PPP1CA, and PEG3 genes in colon adenocarcinoma cell lines: promising treatment targets

Aim

This study investigated the association between methylation status and expression levels of BTG2, PPP1CA, and PEG3 genes in colon cancer.

Background

Aberrant DNA methylation is one of the most important epigenetic modifications in the development of cancer. Evidence indicates that hypermethylation of various tumor suppressor genes could be a potential mechanism of colon tumorigenesis.

Methods

The expression levels of BTG2, PPP1CA, and PEG3 genes were evaluated in HT-29/219, HCT116, SW48, SW742, SW480, and LS180 cell lines using quantitative Real-Time PCR. The methylation status of BTG2 and PPP1CA was determined by methylation-specific PCR (MSP) method, and the methylation pattern of PEG3 was evaluated by bisulfite sequencing PCR (BSP). To investigate the effect of methylation on the expression of these genes, all colon cancer cell lines were treated by 5-Azacitidine (5-Aza) and/or Trichostatin A (TSA).

Results

The expression levels of BTG2, PPP1CA, and PEG3 were highly heterogeneous and quantitatively correlated to their promoter methylation status in the studied colon cancer cell lines. Treatment by 5-Aza and/or TSA increased the expression of the above-named genes in colon cancer cell lines.

Conclusion

Overall, it seems that BTG2, PPP1CA, and PEG3 act as tumor suppressor genes in colon cancer, and methylation is a potential mechanism for their loss of expression. Therefore, these genes may be considered as suitable targets for demethylation approaches and, eventually, colon cancer treatment. Combined treatment by 5-Aza and TSA may be a promising therapeutic strategy for colon cancer treatment. Further studies may contribute to confirm these results.

Bridging the explanatory gaps: What can we learn from a biological agency perspective?

We begin this article by delineating the explanatory gaps left by prevailing gene-focused approaches in our understanding of phenotype determination, inheritance, and the origin of novel traits. We aim not to diminish the value of these approaches but to highlight where their implementation, despite best efforts, has encountered persistent limitations. We then discuss how each of these explanatory gaps can be addressed by expanding research foci to take into account biological agency-the capacity of living systems at various levels to participate in their own development, maintenance, and function by regulating their structures and activities in response to conditions they encounter. Here we aim to define formally what agency and agents are and-just as importantly-what they are not, emphasizing that agency is an empirical property connoting neither intention nor consciousness. Lastly, we discuss how incorporating agency helps to bridge explanatory gaps left by conventional approaches, highlight scientific fields in which implicit agency approaches are already proving valuable, and assess the opportunities and challenges of more systematically incorporating biological agency into research programs.

DNA Methylation and Type 2 Diabetes: Novel Biomarkers for Risk Assessment?

Diabetes is a severe threat to global health. Almost 500 million people live with diabetes worldwide. Most of them have type 2 diabetes (T2D). T2D patients are at risk of developing severe and life-threatening complications, leading to an increased need for medical care and reduced quality of life. Improved care for people with T2D is essential. Actions aiming at identifying undiagnosed diabetes and at preventing diabetes in those at high risk are needed as well. To this end, biomarker discovery and validation of risk assessment for T2D are critical. Alterations of DNA methylation have recently helped to better understand T2D pathophysiology by explaining differences among endophenotypes of diabetic patients in tissues. Recent evidence further suggests that variations of DNA methylation might contribute to the risk of T2D even more significantly than genetic variability and might represent a valuable tool to predict T2D risk. In this review, we focus on recent information on the contribution of DNA methylation to the risk and the pathogenesis of T2D. We discuss the limitations of these studies and provide evidence supporting the potential for clinical application of DNA methylation marks to predict the risk and progression of T2D.

New Pandemic: Obesity and Associated Nephropathy

Incidence of obesity related renal disorders have increased 10-folds in recent years. One of the consequences of obesity is an increased glomerular filtration rate (GFR) that leads to the enlargement of the renal glomerulus, i.e., glomerulomegaly. This heightened hyper-filtration in the setting of type 2 diabetes irreparably damages the kidney and leads to progression of end stage renal disease (ESRD). The patients suffering from type 2 diabetes have progressive proteinuria, and eventually one third of them develop chronic kidney disease (CKD) and ESRD. For ameliorating the progression of CKD, inhibitors of renin angiotensin aldosterone system (RAAS) seemed to be effective, but on a short-term basis only. Long term and stable treatment strategies like weight loss via restricted or hypo-caloric diet or bariatric surgery have yielded better promising results in terms of amelioration of proteinuria and maintenance of normal GFR. Body mass index (BMI) is considered as a traditional marker for the onset of obesity, but apparently, it is not a reliable indicator, and thus there is a need for more precise evaluation of regional fat distribution and amount of muscle mass. With respect to the pathogenesis, recent investigations have suggested perturbation in fatty acid and cholesterol metabolism as the critical mediators in ectopic renal lipid accumulation associated with inflammation, increased generation of ROS, RAAS activation and consequential tubulo-interstitial injury. This review summarizes the renewed approaches for the obesity assessment and evaluation of the pathogenesis of CKD, altered renal hemodynamics and potential therapeutic targets.

Step Count Associations Between Adults at Risk of Developing Diabetes and Their Children: The Feel4Diabetes Study

BACKGROUND

Shared risk factors of type 2 diabetes mellitus (T2DM) between parents at risk and their children, such as low physical activity levels, should be addressed to prevent the development of the disease. The aim of this study was to determine the association of objectively measured step counts per day between parents at risk of developing T2DM and their 6- to 10-year-old children.

METHODS

The baseline data from the Feel4Diabetes study were analyzed. Dyads of children and one parent (n = 250, 54.4% girls and 77.6% mothers) from Belgium were included. Step counts per day during 5 consecutive days from parents and their children were objectively measured with ActiGraph accelerometers.

RESULTS

Adjusted linear regression models indicated that parents' and children's step counts were significantly associated during all days (β = 0.245), weekdays (β = 0.205), and weekend days (β = 0.316) (P ≤ .002 in all cases). Specifically, mother-daughter associations during all days and weekend days and father-son step counts during weekdays and when considering all days were significant.

CONCLUSION

There is a positive association between step counts from adults at risk of developing T2DM and their children, especially in the mother-daughter and father-son dyads.

Methylome-wide association study of central adiposity implicates genes involved in immune and endocrine systems

Aim: We conducted a methylome-wide association study to examine associations between DNA methylation in whole blood and central adiposity and body fat distribution, measured as waist circumference, waist-to-hip ratio and waist-to-height ratio adjusted for body mass index, in 2684 African-American adults in the Atherosclerosis Risk in Communities study. Materials & methods: We validated significantly associated cytosine-phosphate-guanine methylation sites (CpGs) among adults using the Women's Health Initiative and Framingham Heart Study participants (combined n = 5743) and generalized associations in adolescents from The Raine Study (n = 820). Results & conclusion: We identified 11 CpGs that were robustly associated with one or more central adiposity trait in adults and two in adolescents, including CpG site associations near TXNIP, ADCY7, SREBF1 and RAP1GAP2 that had not previously been associated with obesity-related traits.

Prediabetes uncovers differential gene expression at fasting and in response to oral glucose load in immune cells

BACKGROUND AND OBJECTIVE

Metabolic disorders including diabetes are associated with immune cell dysfunction. However, the effect of normal glucose metabolism or impairment thereof on immune cell gene expression is not well known. Hence, in this cross-sectional pilot study, we sought to determine the differences in gene expression in the peripheral blood mono-nuclear cells (PBMCs) of normal glucose tolerant (NGT) and prediabetic (PD) Asian Indian men, at fasting and in response to 75 g oral glucose load.

METHODS

Illumina HT12 bead chip-based microarray was performed on PBMCs at fasting and 2-h post load conditions for NGT (N = 6) and PD (N = 9) subjects. Following normalization and due quality control of the raw data, differentially expressed genes (DEGs) under different conditions within and across the two groups were identified using GeneSpring GX V12.0 software. Paired and unpaired Student's t-tests were applied along with fold change cut-offs for appropriate comparisons. Validation of the microarray data was carried out through real-time qPCR analysis. Significantly regulated biological pathways were analyzed by employing DEGs and DAVID resource. Deconvolution of the DEGs between NGT and PD subjects at fasting was performed using CIBERSORT and genes involved in regulatory T-cell (Treg) function were further analyzed for biological significance.

RESULTS

Glucose load specifically altered the expression of 112 genes in NGT and 356 genes in PD subjects. Biological significance analysis revealed transient up-regulation of innate and adaptive immune response related genes following oral glucose load in NGT individuals, which was not observed in PD subjects. Instead, in the PD group, glucose load led to an increase in the expression of pro-atherogenic and anti-angiogenic genes. Comparison of gene expression at fasting state in PD versus NGT revealed 21,707 differentially expressed genes. Biological significance analysis of the immune function related genes between these two groups (at fasting) revealed higher gene expression of members of the TLR signaling, MHC class II molecules, and T-cell receptor, chemotaxis and adhesion pathways in PD subjects. Expression of interferon-γ (IFN-γ) and TNFα was higher and that of type-1 interferons and TGF-β was lower at fasting state in PD subjects compared to NGT. Additionally, expression of multiple proteasome subunits and protein arginine methyl transferase genes (PRMTs) were higher and that of Treg specific genes was significantly distinct at fasting in PD subjects compared to NGT.

CONCLUSION

Prediabetes uncovers constitutive TLR activation, enhanced IFN-γ signaling, and Treg dysfunction at fasting along with altered gene expression response to oral glucose load.

Relationship of prenatal maternal obesity and diabetes to offspring neurodevelopmental and psychiatric disorders: a narrative review

Obesity and diabetes is a worldwide public health problem among women of reproductive age. This narrative review highlights recent epidemiological studies regarding associations of maternal obesity and diabetes with neurodevelopmental and psychiatric disorders in offspring, and provides an overview of plausible underlying mechanisms and challenges for future human studies. A comprehensive search strategy selected terms that corresponded to the domains of interest (maternal obesity, different types of diabetes, offspring cognitive functions and neuropsychiatric disorders). The databases searched for articles published between January 2010 and April 2019 were PubMed, Web of Science and CINAHL. Evidence from epidemiological studies strongly suggests that maternal pre-pregnancy obesity is associated with increased risks for autism spectrum disorder, attention-deficit hyperactivity disorder and cognitive dysfunction with modest effect sizes, and that maternal diabetes is associated with the risk of the former two disorders. The influence of maternal obesity on other psychiatric disorders is less well studied, but there are reports of associations with increased risks for offspring depression, anxiety, schizophrenia and eating disorders, at modest effect sizes. It remains unclear whether these associations are due to intrauterine mechanisms or explained by confounding family-based sociodemographic, lifestyle and genetic factors. The plausible underlying mechanisms have been explored primarily in animal models, and are yet to be further investigated in human studies.

DNA methylation pattern changes following a short-term hypocaloric diet in women with obesity

BACKGROUND/OBJECTIVES

We aimed to investigate the effects of short-term hypocaloric diet-induced weight loss on DNA methylation profile in leukocytes from women with severe obesity.

METHODS

Eleven women with morbid obesity (age: 36.9 ± 10.3 years; BMI: 58.5 ± 10.5 kg/m²) were assessed before and after 6 weeks of a hypocaloric dietary intervention. The participants were compared with women of average weight and the same age (age: 36.9 ± 11.8 years; BMI: 22.5 ± 1.6 kg/m²). Genome-wide DNA methylation analysis was performed in DNA extracted from peripheral blood leukocytes using the Infinium Human Methylation 450 BeadChip assay. Changes (Δβ) in the methylation level of each CpGs were calculated. A threshold with a minimum value of 10%, p < 0.001, for the significant CpG sites based on Δβ and a false discovery rate of <0.05 was set.

RESULTS

Dietary intervention changed the methylation levels at 16,064 CpG sites. These CpGs sites were related to cancer, cell cycle-related, MAPK, Rap1, and Ras signaling pathways. However, regardless of hypocaloric intervention, a group of 878 CpGs (related to 649 genes) remained significantly altered in obese women when compared with normal-weight women. Pathway enrichment analysis identified genes related to the cadherin and Wnt pathway, angiogenesis signaling, and p53 pathways by glucose deprivation.

CONCLUSION

A short-term hypocaloric intervention in patients with severe obesity partially restored the obesity-related DNA methylation pattern. Thus, the full change of obesity-related DNA methylation patterns could be proportional to the weight-loss rate in these patients after dietary interventions.

Possible Adverse Effects of High-Dose Nicotinamide: Mechanisms and Safety Assessment

Nicotinamide (NAM) at doses far above those recommended for vitamins is suggested to be effective against a wide spectrum of diseases and conditions, including neurological dysfunctions, depression and other psychological disorders, and inflammatory diseases. Recent increases in public awareness on possible pro-longevity effects of nicotinamide adenine dinucleotide (NAD+) precursors have caused further growth of NAM consumption not only for clinical treatments, but also as a dietary supplement, raising concerns on the safety of its long-term use. However, possible adverse effects and their mechanisms are poorly understood. High-level NAM administration can exert negative effects through multiple routes. For example, NAM by itself inhibits poly(ADP-ribose) polymerases (PARPs), which protect genome integrity. Elevation of the NAD+ pool alters cellular energy metabolism. Meanwhile, high-level NAM alters cellular methyl metabolism and affects methylation of DNA and proteins, leading to changes in cellular transcriptome and proteome. Also, methyl metabolites of NAM, namely methylnicotinamide, are predicted to play roles in certain diseases and conditions. In this review, a collective literature search was performed to provide a comprehensive list of possible adverse effects of NAM and to provide understanding of their underlying mechanisms and assessment of the raised safety concerns. Our review assures safety in current usage level of NAM, but also finds potential risks for epigenetic alterations associated with chronic use of NAM at high doses. It also suggests directions of the future studies to ensure safer application of NAM.

PKR inhibitors suppress endoplasmic reticulum stress and subdue glucolipotoxicity-mediated impairment of insulin secretion in pancreatic beta cells

Type 2 diabetes mellitus is characterized by insulin resistance and hypersecretion of insulin from the pancreas to compensate for decreased insulin sensitivity in the peripheral tissues. In later stages of the disease insulin-secreting beta cell degeneration commences and patients require insulin replacement therapy in order to accomplish proper regulation of their blood glucose. Endoplasmic reticulum (ER) stress in the beta cells is one of the factors contributing to this detrimental effect. Protein kinase R (PKR) is a cellular stress kinase activated by ER stress and contributing to degeneration of pancreatic islets. In order to determine whether inhibition of PKR activation by specific small molecule inhibitors of PKR ameliorates pancreatic insulin secretion capacity, we treated beta cells with two imidazole/oxindole-derived inhibitors of PKR kinase, imoxin (C16) and 2-aminopurine (2-AP), in the presence of ER stress. Our results demonstrate that PKR inhibition suppresses tunicamycin-mediated ER stress without altering the insulin production capacity of the cells. Palmitic acid-mediated suppression of insulin secretion, however, was subdued significantly by PKR inhibitor treatment through an ER stress-related mechanism. We suggest that PKR inhibitor treatment may be used to increase the insulin secretion capacity of the pancreas in later stages of diabetes.

Hypermethylation in Calca Promoter Inhibited ASC Osteogenic Differentiation in Rats with Type 2 Diabetic Mellitus

The abnormal environment of type 2 diabetes mellitus (T2DM) leads to a substantial decrease in osteogenic function of stem cells. However, the gene sequence does not vary before and after disease for the patient. This phenomenon may be related to changes in osteogenesis-related gene expression caused by DNA methylation. In this study, we established T2DM models to extract adipose-derived stem cells (ASCs) for different gene identifications through DNA methylation sequencing. Specific fragments of methylation changes in the target gene (Calca) were identified by IGV analysis. CGRP was applied to compare the effects on ASCs-T2DM morphology via phalloidin staining, proliferation through CCK-8 assay, and osteogenic differentiation with osteogenic staining, qPCR, and repair of calvarial defect. Furthermore, 5-azacytidine (5-az) was used to intervene ASCs-T2DM to verify the relationship between the methylation level of the target fragment and expression of Calca. We found that the DNA methylation level of target fragment of Calca in ASCs-T2DM was higher than that in ASCs-C. CGRP intervention showed that it did not change the morphology of ASCs-T2DM but could improve proliferation within a certain range. Meanwhile, it could significantly enhance the formation of ALP and calcium nodules in ASCs-T2DM, increase the expression of osteogenesis-related genes in vitro, and promote the healing of calvarial defects of T2DM rat in a concentration-dependent manner. 5-az intervention indicated that the reduction of the methylation level in Calca target fragment of ASCs-T2DM indeed escalated the gene expression, which may be related to DNMT1. Taken together, the environment of T2DM could upregulate the methylation level in the promoter region of Calca and then decrease the Calca expression. The coding product of Calca revealed a promoting role for osteogenic differentiation of ASCs-T2DM. This result provides an implication for us to understand the mechanism of the decreased osteogenic ability of ASCs-T2DM and improve its osteogenic capacity.

Epigenetic silencing of the ANKRD26 gene correlates to the pro-inflammatory profile and increased cardio-metabolic risk factors in human obesity

BACKGROUND

Obesity is a major worldwide threat to human health. Increasing evidence indicates that epigenetic modifications have a major impact on the natural history of this disorder. Ankyrin Repeat Domain 26 (Ankrd26) is involved in the development of both obesity and diabetes in mice and is modulated by environmentally induced epigenetic modifications. This study aims at investigating whether impaired ANKRD26 gene expression and methylation occur in human obesity and whether they correlate to the phenotype of these subjects.

RESULTS

We found that downregulation of ANKRD26 mRNA and hyper-methylation of a specific region of the ANKRD26 promoter, embedding the CpG dinucleotides - 689, - 659, and - 651 bp, occur in peripheral blood leukocytes from obese compared with the lean subjects. ANKRD26 gene expression correlates inversely to the percentage of DNA methylation at these 3 CpG sites. Luciferase assays reveal a cause-effect relationship between DNA methylation at the 3 CpG sites and ANKRD26 gene expression. Finally, both ANKRD26 mRNA levels and CpG methylation correlate to body mass index and to the pro-inflammatory status and the increased cardio-metabolic risk factors of these same subjects.

CONCLUSION

Downregulation of the ANKRD26 gene and hyper-methylation at specific CpGs of its promoter are common abnormalities in obese patients. These changes correlate to the pro-inflammatory profile and the cardio-metabolic risk factors of the obese individuals, indicating that, in humans, they mark adverse health outcomes.

Public health research needs for molecular epidemiology and to emphasize homeostasis - could the omnipotent endopeptidase inhibitor α-2-macroglobulin be a meaningful biomarker?

Public health authorities in low- and middle-income countries face dramatic challenges in handling rapidly increasing non-communicable diseases (NCDs), due to the epidemiological- and particularly nutritional transition. Among major reasons for the development of NCDs are smoking and alcohol, but overnutrition and obesity are also major threats to population health. Obesity is related to diabetes and cancer, but also has a genetic background. It is difficult to recommend a healthy nutrition. This is because of conflicting nutritional conceptions, and given the complexity of human metabolism understanding this topic can be difficult for the laymen.  Public health measures advocating physical activity and refraining from high intake of energy, sugar and soft drinks need to be enhanced by supporting the ‘intrinsic motivation’ to preserve a good health. The mission of public health should be to increase awareness about the complexity of human metabolism, and the involvement of genetic and epigenetics in health and diseases. To maintain homeostasis, means to keep an optimal relationship between catabolism and synthesis, seems to be of particular interest. Preconditions for this is, that public health institutions within the administration- and academic sector follow up developments in life science and molecular biology and conduct population-based research making use of molecular epidemiology, especially those related to key metabolic steps and maintenance of ‘homeostasis’, in balancing catabolism and anabolism. A prospective biomarker for this situation might be α-2-macroglobulin.

Hyperactive CREB signaling pathway involved in the pathogenesis of polycystic ovarian syndrome revealed by patient-specific induced pluripotent stem cell modeling

OBJECTIVE

To study whether and how the pathogenesis of polycystic ovarian syndrome (PCOS) is related to epigenetic aberrations.

DESIGN

A case-control experimental study.

SETTING

Tertiary university hospital.

PATIENT(S)

Eighteen patients with PCOS and ten non-PCOS control subjects.

INTERVENTIONS(S)

Patient-specific induced pluripotent stem cells (iPSCs) were obtained from skin fibroblasts through the application of nonviral episomal reprogramming and were differentiated into ovarian granulosa cells (GCs) with the use of a cocktail of growth factors. Primary ovarian GCs were collected during transvaginal oocyte retrieval surgery.

MAIN OUTCOME MEASURE(S)

Characterization and functional validation of iPSC-derived GCs were conducted. Whole-genomic DNA methylation profiles in women with and without PCOS in both iPSC-derived GCs and primary adult GCs were analyzed with the use of the Illumina 850K MethylationEPIC Beadchip.

RESULT(S)

The iPSC-derived GCs successfully expressed GC-associated genes and aromatase activity after differentiation. Whole-genomic DNA methylation analysis of the iPSC-derived GCs and adult GCs both revealed a hyperactive CREB signaling pathway in the PCOS group compared with the control group. The expression of CREB-binding protein (CBP) mRNA was significantly higher in the iPSC-derived GCs in the PCOS group, and the expression of CBP protein was also significantly higher in the primary GCs from women with PCOS.

CONCLUSION(S)

The combination of DNA methylomic analysis in primary adult GCs and iPSC-derived GCs showed that a preserved persistent hyperactivation of the CREB signaling pathway might be involved in the pathogenesis of PCOS. These results could have implications on the early developmental origin, inheritance nature, and environmental interaction effects of this disease.

Family Legacy of Diabetes-Related Behaviors: An Exploration of the Experiences of African American Parents and Adult Children

African Americans are at higher risk of developing type 2 diabetes mellitus (T2DM), and this risk may be influenced by familial experiences and cultural norms throughout the life course. This led us to conduct this study of 20 African American families with strong histories of T2DM to explore familial complexities that prevent or help manage diabetic symptoms. Experiences were analyzed inductively through individual family profiles created using content-analytic summaries. When profiles were further analyzed for emerging and theoretically informed data patterns, two themes emerged: (a) family interactions characterized by T2DM-related actions and communication patterns, and (b) intergenerational patterns of openness characterized by variations in approach within generational cohort and parental gender. Through inquiries related to intergenerational experiences with T2DM, nursing and health care professionals may be better able to tailor and promote success for prevention and management of behaviors among high-risk African Americans.

Improved control of non-communicable diseases (NCDs) requires an additional advanced concept for public health - a perspective from a middle-income country

A major consequence of all elements of the 'epidemiological transition' is the rapid emergence of non-communicable diseases (NCDs) in low- and middle-income countries. In contrast to the outcomes of the 'Alma Ata Conference for Primary Health Care', it has not yet been possible to introduce an equally powerful health policy for the prevention and control of NCDs. Major strategies so far are to advise individuals not to smoke and drink alcohol in excess. Additionally, 'healthy' nutrition and increased physical activity are also advocated. Policy for preventing and working against NCDs is now part of the Sustainable Development Goals, specifically target 3.4. So far, attempts to soften the influence of NCDs on the health of the people in low- and middle-income countries have been unsuccessful. It is argued here that additional concepts on how public health could operate against NCDs are needed.  Major risk factors for NCDs interfere with and alter complex steps within the human metabolism.  This paper explores how human metabolism works by assessing advances in molecular biology and research in genetics, epigenetics and gerontology. Recent developments in these scientific disciplines shed light on the complexity of how human health is maintained and diseases are invoked. Public health bodies should be aware, interested and possibly contribute to the aforementioned areas of interest, as far as NCDs are concerned, and translate major developments in a way, that could be useful in improving population health.

Epigenome-wide association study in whole blood on type 2 diabetes among sub-Saharan African individuals: findings from the RODAM study

BACKGROUND

Type 2 diabetes (T2D) results from a complex interplay between genetics and the environment. Several epigenome-wide association studies (EWAS) have found DNA methylation loci associated with T2D in European populations. However, data from African populations are lacking. We undertook the first EWAS for T2D among sub-Saharan Africans, aiming at identifying ubiquitous and novel DNA methylation loci associated with T2D.

METHODS

The Illumina 450k DNA-methylation array was used on whole blood samples of 713 Ghanaian participants (256 with T2D, 457 controls) from the cross-sectional Research on Obesity and Diabetes among African Migrants (RODAM) study. Differentially methylated positions (DMPs) for T2D and HbA1c were identified through linear regression analysis adjusted for age, sex, estimated cell counts, hybridization batch, array position and body mass index (BMI). We also did a candidate analysis of previously reported EWAS loci for T2D in non-African populations, identified through a systematic literature search.

RESULTS

Four DMPs [cg19693031 (TXNIP), cg04816311 (C7orf50), cg00574958 (CPT1A), cg07988171 (TPM4)] were associated with T2D after correction for inflation by possible systematic biases. The most strongly associated DMP-cg19693031, TXNIP (P = 2.6E-19) -showed hypomethylation in T2D cases compared with controls. Two out of the four DMPs [cg19693031 (TXNIP), cg04816311 (C7orf50)] remained associated with T2D after adjustment for BMI, and one locus [cg07988171 (TPM4)] that has not been reported previously.

CONCLUSIONS

In this first EWAS for T2D in sub-Saharan Africans, we have identified four DMPs at epigenome-wide level, one of which is novel. These findings provide insight into the epigenetic loci that underlie the burden of T2D in sub-Saharan Africans.

A Perception on Genome-Wide Genetic Analysis of Metabolic Traits in Arab Populations

Despite dedicated nation-wide efforts to raise awareness against the harmful effects of fast-food consumption and sedentary lifestyle, the Arab population continues to struggle with an increased risk for metabolic disorders. Unlike the European population, the Arab population lacks well-established genetic risk determinants for metabolic disorders, and the transferability of established risk loci to this population has not been satisfactorily demonstrated. The most recent findings have identified over 240 genetic risk loci (with ~400 independent association signals) for type 2 diabetes, but thus far only 25 risk loci (ADAMTS9, ALX4, BCL11A, CDKAL1, CDKN2A/B, COL8A1, DUSP9, FTO, GCK, GNPDA2, HMG20A, HNF1A, HNF1B, HNF4A, IGF2BP2, JAZF1, KCNJ11, KCNQ1, MC4R, PPARγ, SLC30A8, TCF7L2, TFAP2B, TP53INP1, and WFS1) have been replicated in Arab populations. To our knowledge, large-scale population- or family-based association studies are non-existent in this region. Recently, we conducted genome-wide association studies on Arab individuals from Kuwait to delineate the genetic determinants for quantitative traits associated with anthropometry, lipid profile, insulin resistance, and blood pressure levels. Although these studies led to the identification of novel recessive variants, they failed to reproduce the established loci. However, they provided insights into the genetic architecture of the population, the applicability of genetic models based on recessive mode of inheritance, the presence of genetic signatures of inbreeding due to the practice of consanguinity, and the pleiotropic effects of rare disorders on complex metabolic disorders. This perspective presents analysis strategies and study designs for identifying genetic risk variants associated with diabetes and related traits in Arab populations.

Educating for Equity Care Framework: Addressing social barriers of Indigenous patients with type 2 diabetes

OBJECTIVE

To present a clinical framework for addressing critical social elements for Indigenous patients with type 2 diabetes.

SOURCES OF INFORMATION

The Educating for Equity (E4E) Care Framework was developed through a rigorous analysis of qualitative research that included the perspectives of Indigenous patients (n = 32), physicians (n = 28), and Indigenous health curriculum developers (n = 5) across Canada. A national advisory group of Indigenous health experts, educators, leaders, physicians, and community members provided feedback on integrating analysis from primary research into recommendations for physicians. Systematic literature reviews were conducted and a nominal group technique process helped forge research team consensus around the framework's themes and recommendations.

MAIN MESSAGE

For Indigenous patients with type 2 diabetes, social factors arising from the legacy of colonization are often barriers to improved diabetes outcomes, while culture is often not recognized as a facilitator in diabetes management. Structural competency in balance with cultural safety should be central to the clinical process when negotiating diabetes management with Indigenous patients. The E4E Care Framework presented in this article provides recommendations to navigate this terrain.

CONCLUSION

A focus on social and cultural elements is fundamental to effective diabetes care among Indigenous patients. The E4E Care Framework is a resource that can help clinicians improve Indigenous patients' capacity for change in a way that acknowledges the social factors that affect the increasing diabetes rates, while using a cultural lens to facilitate improved outcomes.

[Not Available]

Objectif

Présenter un cadre clinique afin de prendre en considération les éléments sociaux critiques pour les patients autochtones atteints de diabète de type 2.

Sources de l’information

Le Cadre de soins fondé sur l’éducation pour l’équité (Educating for Equity [E4E] Care Framework) a été produit à la suite de l’analyse rigoureuse d’une recherche qualitative portant sur les points de vue de patients autochtones (n = 32), de médecins (n = 28) et d’élaborateurs de cursus en santé autochtone (n = 5) dans toutes les régions du Canada. Un groupe consultatif national formé d’experts en santé autochtone, d’enseignants, de dirigeants, de médecins et de membres de la collectivité a exprimé des commentaires sur une analyse intégrant la recherche primaire dans les recommandations à l’intention des médecins. Des revues systématiques de la documentation ont été effectuées, et la technique du groupe nominal a servi à en arriver à un consensus de l’équipe de recherche sur les thèmes et les recommandations du cadre.

Message principal

Pour les patients autochtones atteints du diabète de type 2, les facteurs sociaux découlant des séquelles de la colonisation sont souvent des obstacles à l’amélioration des issues du diabète, et la culture n’est souvent pas reconnue comme une facilitatrice dans la gestion du diabète. Il est essentiel que le processus clinique unisse la compétence structurelle en juste équilibre avec la sécurité culturelle dans la négociation de la gestion du diabète avec des patients autochtones. Le Cadre de soins fondé sur l’éducation pour l’équité présenté dans cet article propose des recommandations pour naviguer dans ces eaux.

Conclusion

Il est fondamental de mettre l’accent sur les éléments sociaux et culturels pour offrir des soins du diabète efficaces aux patients autochtones. Le Cadre de soins fondé sur l’éducation pour l’équité est une ressource qui peut aider les cliniciens à améliorer la capacité des patients autochtones à apporter des changements d’une façon qui reconnaît les facteurs sociaux qui influencent les taux croissants de diabète, tout en ayant une perspective culturelle pour favoriser de meilleurs résultats.

Role of CTRP3, CTRP9 and MCP-1 for the evaluation of T2DM associated coronary artery disease in Egyptian postmenopausal females

C1q complement/tumor necrosis factor (TNF)—related protein (CTRP) family comprises of 15 proteins that posses important implications in energy homeostasis, infection and inflammation. However, their roles in diabetes mellitus (DM) and its vascular complications have not been completely assessed. This works aims to study the association of two CTRPs; 3 and 9, with pro-inflammatory cytokine monocyte chemoattractant protein-1 (MCP-1), and biochemical parameters of type 2 diabetes (T2D), dyslipidemia and coronary artery disease (CAD).Methods: Biochemical markers and serum levels of CTRPs and MCP-1 were measured in 86 postmenopausal females. Subjects were divided over four groups; 13 apparent healthy subjects as control (group I), 29 patients with CAD (group II), 29 patients with T2D ≥5 years (group III) and 15 patients with CAD secondary to T2D (group IV). Serum CTRP3, CTRP9, MCP-1 and insulin were measured by ELISA.Results: Serum CTRP3 levels were found to be significantly higher in group III and IV, whereas, it was significantly lower in group II on comparing to group I. While, CTRP9 levels were significantly decreased in group II, III and IV on comparing to group I. MCP-1 levels were found to be significantly increased in groups II, III and IV on comparison with group I. Both CTRPs were significantly negatively correlated with each other. While MCP-1 was significantly correlated negatively to CTRP9.Conclusion: This study associates the possible role of CTRP3, CTRP9 and MCP-1/CCL2 in the diagnosis/prognosis of CAD complication in T2D postmenopausal females.

MANF: A New Player in the Control of Energy Homeostasis, and Beyond

All human behaviors, including the control of energy homeostasis, are ultimately mediated by neuronal activities in the brain. Neurotrophic factors represent a protein family that plays important roles in regulating neuronal development, function, and survival. It has been well established that canonical neurotrophic factors, such as brain-derived neurotrophic factor (BDNF) and ciliary neurotrophic factor (CNTF), play important roles in the central regulation of energy homeostasis. Recently, a class of non-canonical neurotrophic factors, represented by mesencephalic astrocyte-derived neurotrophic factor (MANF), has been discovered. MANF is structurally and functionally distinct from those canonical neurotrophic factors, hence raising the issue of MANF being non-canonical. Nonetheless, emerging evidence suggests that MANF is critically involved in many neuronal activities. Here, we review our current understanding about the functions of MANF in the brain, with a primary focus on the control of energy homeostasis.

Genome-wide methylation analysis identifies ELOVL5 as an epigenetic biomarker for the risk of type 2 diabetes mellitus

Genome-wide DNA methylation has been implicated in complex human diseases. Here, we identified epigenetic biomarkers for type 2 diabetes (T2D) underlying obesogenic environments. In a blood-based DNA methylation analysis of 11 monozygotic twins (MZTW) discordant for T2D, we discovered genetically independent candidate methylation sites. In a follow-up replication study (17 MZTW pairs) for external validation, we replicated the T2D-association at a novel CpG signal in the ELOVL fatty acid elongase 5 (ELOVL5) gene specific to T2D-discordant MZTW. For concordant DNA methylation signatures in tissues, we further confirmed that a CpG site (cg18681426) was associated with adipogenic differentiation between human preadipocytes and adipocytes isolated from the same biopsy sample. In addition, the ELOVL5 gene was significantly differentially expressed in adipose tissues from unrelated T2D patients and in human pancreatic islets. Our results demonstrate that blood-derived DNA methylation is associated with T2D risk as a proxy for cumulative epigenetic status in human adipose and pancreatic tissues. Moreover, ELOVL5 expression was increased in cellular and mouse models of induced obesity-related diabetes. These findings may provide new insights into epigenetic architecture by uncovering methylation-based biomarkers.

Epigenetics Variation and Pathogenesis in Diabetes

PURPOSE OF REVIEW

Great strides have recently been made in elucidating the role of genetic sequence variation in diabetes pathogenesis. Increasingly, studies are focusing on other factors that may contribute to the pathogenesis of diabetes, such as epigenetics, a term "traditionally" encompassing changes to the DNA that do not alter sequence and are heritable (primary methylation and histone modification) but often expanded to include microRNAs. This review summarizes latest findings on the role of epigenetics in diabetes pathogenesis.

RECENT FINDINGS

Recent studies illustrate roles for methylation changes, histone modification, imprinting, and microRNAs across several diabetes types and complications. Notably, methylation changes in the human leukocyte antigen (HLA) region have been found to precede the development of type 1 diabetes. In type 2 diabetes, lifestyle factors appear to interact with epigenetic mechanisms in pathogenesis. Emerging technologies have allowed increasingly comprehensive descriptive analysis of the role of epigenetic mechanisms in diabetes pathogenesis which have yielded meaningful insights into effects on expression of relevant genes. These findings have the potential to inform future development of predictive testing to enable primary prevention and further work to uncover the complex pathogenesis of diabetes.

Metabolic Flexibility as an Adaptation to Energy Resources and Requirements in Health and Disease

The ability to efficiently adapt metabolism by substrate sensing, trafficking, storage, and utilization, dependent on availability and requirement, is known as metabolic flexibility. In this review, we discuss the breadth and depth of metabolic flexibility and its impact on health and disease. Metabolic flexibility is essential to maintain energy homeostasis in times of either caloric excess or caloric restriction, and in times of either low or high energy demand, such as during exercise. The liver, adipose tissue, and muscle govern systemic metabolic flexibility and manage nutrient sensing, uptake, transport, storage, and expenditure by communication via endocrine cues. At a molecular level, metabolic flexibility relies on the configuration of metabolic pathways, which are regulated by key metabolic enzymes and transcription factors, many of which interact closely with the mitochondria. Disrupted metabolic flexibility, or metabolic inflexibility, however, is associated with many pathological conditions including metabolic syndrome, type 2 diabetes mellitus, and cancer. Multiple factors such as dietary composition and feeding frequency, exercise training, and use of pharmacological compounds, influence metabolic flexibility and will be discussed here. Last, we outline important advances in metabolic flexibility research and discuss medical horizons and translational aspects.

SLC35B4, an Inhibitor of Gluconeogenesis, Responds to Glucose Stimulation and Downregulates Hsp60 among Other Proteins in HepG2 Liver Cell Lines

SLC35B4, solute receptor for UDP-N-acetylglucosamine and UDP-xylose, is associated with diabetes and predisposing conditions. This study investigated the localization of SLC35B4 and compared the differential expression between a knockdown of SLC35B4 and controls in HepG2. Responsiveness to glucose, expression, and localization were assayed using Western blot and immunostaining. Localization was confirmed using a proximity ligation assay. Two-dimensional (2D) gel electrophoresis and MALDI-TOF were used to identify differentially expressed proteins and pathway analysis was performed. SLC35B4 was increased by 60% upon glucose stimulation and localized in Golgi apparatus and endoplasmic reticulum. Presence of SLC35B4 in the Golgi apparatus suggests its involvement in the biosynthesis of glycoconjugate proteins. Four proteins were markedly under-expressed (Hsp60, HspA8, TUBA1A, and ENO1) and linked to the pathogenesis of diabetes or post-translationally modified by O-GlcNAc. Glucose levels activate SLC35B4 expression. This triggers a downstream effect via Hsp60 and other proteins. We hypothesize that the downstream effect on the proteins is mediated via altering the glycosylation pattern inside liver cells. The downstream cascade ultimately alters the ability of cultured liver cells to inhibit endogenous glucose production, and this could play a role in the association of the above-listed genes with the pathogenesis of diabetes.

The Interaction of Genetic Predisposition and Socioeconomic Position With Type 2 Diabetes Mellitus: Cross-Sectional and Longitudinal Analyses From the Lifelines Cohort and Biobank Study

OBJECTIVE

A strong genetic predisposition for type 2 diabetes mellitus (T2DM) may aggravate the negative effects of low socioeconomic position (SEP) in the etiology of the disorder. This study aimed to examine cross-sectional and longitudinal associations and interactions of a genetic risk score (GRS) and SEP with T2DM and to investigate whether clinical and behavioral risk factors can explain these associations and interactions.

METHODS

We used data from 13,027 genotyped participants from the Lifelines study. The GRS was based on single-nucleotide polymorphisms genome-wide associated with T2DM and was categorized into tertiles. SEP was measured as educational level. T2DM was based on biological markers, recorded medication use, and self-reports. Cross-sectional and longitudinal associations and interactions between the GRS and SEP on T2DM were examined.

RESULTS

The combination of a high GRS and low SEP had the strongest association with T2DM in cross-sectional (odds ratio = 3.84, 95% confidence interval = 2.28-6.46) and longitudinal analyses (hazard ratio = 2.71, 1.39-5.27), compared with a low GRS and high SEP. Interaction between a high GRS and a low SEP was observed in cross-sectional (relative excess risk due to interaction = 1.85, 0.65-3.05) but not in longitudinal analyses. Clinical and behavioral risk factors mostly explained the observed associations and interactions.

CONCLUSIONS

A high GRS combined with a low SEP provides the highest risk for T2DM. These factors also exacerbated each other's impact cross-sectionally but not longitudinally. Preventive measures should target individual and contextual factors of this high-risk group to reduce the risk of T2DM.

Altered intragenic DNA methylation of HOOK2 gene in adipose tissue from individuals with obesity and type 2 diabetes

Aims/Hypothesis

Failure in glucose response to insulin is a common pathology associated with obesity. In this study, we analyzed the genome wide DNA methylation profile of visceral adipose tissue (VAT) samples in a population of individuals with obesity and assessed whether differential methylation profiles are associated with the presence of type 2 diabetes (T2D).

Methods

More than 485,000 CpG genome sites from VAT samples from women with obesity undergoing gastric bypass (n = 18), and classified as suffering from type 2 diabetes (T2D) or not (no type 2 diabetes, NT2D), were analyzed using DNA methylation arrays.

Results

We found significant differential methylation between T2D and NT2D samples in 24 CpGs that map with sixteen genes, one of which, HOOK2, demonstrated a significant correlation between differentially hypermethylated regions on the gene body and the presence of type 2 diabetes. This was validated by pyrosequencing in a population of 91 samples from both males and females with obesity. Furthermore, when these results were analyzed by gender, female T2D samples were found hypermethylated at the cg04657146-region and the cg 11738485-region of HOOK2 gene, whilst, interestingly, male samples were found hypomethylated in this latter region.

Conclusion

The differential methylation profile of the HOOK2 gene in individuals with T2D and obesity might be related to the attendant T2D, but further studies are required to identify the potential role of HOOK2 gene in T2D disease. The finding of gender differences in T2D methylation of HOOK2 also warrants further investigation.