Effects of glucose-lowering drugs on cardiovascular outcomes in patients with type 2 diabetes: an update.

INTRODUCTION: Over the last few years, there has been a substantial increase in the data available about the benefits of sodium-glucose cotransporter-2 (SGLT2) inhibitors and glucagon-like peptide-1 receptor agonists (GLP-1 RAs) in improving cardiovascular and renal outcomes in patients with type 2 diabetes (T2D). Very little new information is available for the other groups of glucose-lowering drugs. AREAS COVERED: This brief report summarizes the recent information about the respective benefits of the two newer groups of glucose-lowering drugs and the effects on cardiovascular risk factors that may be involved in these benefits. The articles reviewed were identified by a Medline search. EXPERT OPINION: Recent guidelines recommend SGLT2 inhibitors or GLP-1 RAs with proven cardiovascular disease benefits as potential first line treatment for patients with T2D and established atherosclerotic cardiovascular disease (ASCVD) or those with high risk of ASCVD or with chronic kidney disease or heart failure. Both groups of drugs have been shown to reduce major adverse cardiovascular events, but the mechanisms vary between them. SGLT2 inhibitors are preferred for the treatment and prevention of heart failure and chronic kidney disease, whereas GLP-1 RAs are more effective in reducing body weight and improving glycemic control in patients with T2D.

Cardiorenal Benefits of Finerenone in Different Races and Kidney Function in Patients with Chronic Kidney Disease.

BACKGROUND: The mineralocorticoid receptor plays an important pathophysiological role in cardiorenal diseases by causing inflammation and fibrosis. Mineralocorticoid receptor antagonists (MRAs) are well known in treating cardiovascular disease and diverse nephropathies. However, the first-generation MRA (spironolactone) and the second-generation MRA (eplerenone) remain underutilized because of the risk of inducing severe adverse events. As a selective nonsteroidal MRA, finerenone is safer and more effective and improves cardiorenal outcomes in patients with chronic kidney disease (CKD) and type 2 diabetes mellitus (T2DM). However, the effect of finerenone on cardiorenal outcomes in patients of different races and kidney function (estimated glomerular filtration rate) is unclear. SUMMARY: In this review, we summarized the impact of finerenone on patients with CKD and T2DM from randomized controlled trials. The synthesis of published data aims to address the questions pertaining to the cardiorenal benefits of finerenone among various racial groups and different levels of kidney function. KEY MESSAGE: Finerenone presents racial differences and effects associated with kidney function in CKD and T2DM patients. Due to the limited data for subgroups, it is prudent to approach the conclusion with caution.

GLP-1 receptor agonists and atherosclerosis protection: the vascular endothelium takes center stage.

Atherosclerotic cardiovascular disease is a chronic condition that often copresents with type 2 diabetes and obesity. Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are incretin mimetics endorsed by major professional societies for improving glycemic status and reducing atherosclerotic risk in people living with type 2 diabetes. Although the cardioprotective efficacy of GLP-1RAs and their relationship with traditional risk factors are well established, there is a paucity of publications that have summarized the potentially direct mechanisms through which GLP-1RAs mitigate atherosclerosis. This review aims to narrow this gap by providing comprehensive and in-depth mechanistic insight into the antiatherosclerotic properties of GLP-1RAs demonstrated across large outcome trials. Herein, we describe the landmark cardiovascular outcome trials that triggered widespread excitement around GLP-1RAs as a modern class of cardioprotective agents, followed by a summary of the origins of GLP-1RAs and their mechanisms of action. The effects of GLP-1RAs at each major pathophysiological milestone of atherosclerosis, as observed across clinical trials, animal models, and cell culture studies, are described in detail. Specifically, this review provides recent preclinical and clinical evidence that suggest GLP-1RAs preserve vessel health in part by preventing endothelial dysfunction, achieved primarily through the promotion of angiogenesis and inhibition of oxidative stress. These protective effects are in addition to the broad range of atherosclerotic processes GLP-1RAs target downstream of endothelial dysfunction, which include systemic inflammation, monocyte recruitment, proinflammatory macrophage and foam cell formation, vascular smooth muscle cell proliferation, and plaque development.

Genetic drivers of heterogeneity in type 2 diabetes pathophysiology.

Type 2 diabetes (T2D) is a heterogeneous disease that develops through diverse pathophysiological processes1,2 and molecular mechanisms that are often specific to cell type3,4. Here, to characterize the genetic contribution to these processes across ancestry groups, we aggregate genome-wide association study data from 2,535,601 individuals (39.7% not of European ancestry), including 428,452 cases of T2D. We identify 1,289 independent association signals at genome-wide significance (P < 5 × 10-8) that map to 611 loci, of which 145 loci are, to our knowledge, previously unreported. We define eight non-overlapping clusters of T2D signals that are characterized by distinct profiles of cardiometabolic trait associations. These clusters are differentially enriched for cell-type-specific regions of open chromatin, including pancreatic islets, adipocytes, endothelial cells and enteroendocrine cells. We build cluster-specific partitioned polygenic scores5 in a further 279,552 individuals of diverse ancestry, including 30,288 cases of T2D, and test their association with T2D-related vascular outcomes. Cluster-specific partitioned polygenic scores are associated with coronary artery disease, peripheral artery disease and end-stage diabetic nephropathy across ancestry groups, highlighting the importance of obesity-related processes in the development of vascular outcomes. Our findings show the value of integrating multi-ancestry genome-wide association study data with single-cell epigenomics to disentangle the aetiological heterogeneity that drives the development and progression of T2D. This might offer a route to optimize global access to genetically informed diabetes care.

Genetic risk converges on regulatory networks mediating early type 2 diabetes.

Type 2 diabetes mellitus (T2D), a major cause of worldwide morbidity and mortality, is characterized by dysfunction of insulin-producing pancreatic islet ß cells1,2. T2D genome-wide association studies (GWAS) have identified hundreds of signals in non-coding and ß cell regulatory genomic regions, but deciphering their biological mechanisms remains challenging3-5. Here, to identify early disease-driving events, we performed traditional and multiplexed pancreatic tissue imaging, sorted-islet cell transcriptomics and islet functional analysis of early-stage T2D and control donors. By integrating diverse modalities, we show that early-stage T2D is characterized by ß cell-intrinsic defects that can be proportioned into gene regulatory modules with enrichment in signals of genetic risk. After identifying the ß cell hub gene and transcription factor RFX6 within one such module, we demonstrated multiple layers of genetic risk that converge on an RFX6-mediated network to reduce insulin secretion by ß cells. RFX6 perturbation in primary human islet cells alters ß cell chromatin architecture at regions enriched for T2D GWAS signals, and population-scale genetic analyses causally link genetically predicted reduced RFX6 expression with increased T2D risk. Understanding the molecular mechanisms of complex, systemic diseases necessitates integration of signals from multiple molecules, cells, organs and individuals, and thus we anticipate that this approach will be a useful template to identify and validate key regulatory networks and master hub genes for other diseases or traits using GWAS data.

Insulin and aging - a disappointing relationship.

Experimental studies in animal models of aging such as nematodes, fruit flies or mice have observed that decreased levels of insulin or insulin signaling promotes longevity. In humans, hyperinsulinemia and concomitant insulin resistance are associated with an elevated risk of age-related diseases suggestive of a shortened healthspan. Age-related disorders include neurodegenerative diseases, hypertension, cardiovascular disease, and type 2 diabetes. High ambient insulin concentrations promote increased lipogenesis and fat storage, heightened protein synthesis and accumulation of non-functional polypeptides due to limited turnover capacity. Moreover, there is impaired autophagy activity, and less endothelial NO synthase activity. These changes are associated with mitochondrial dysfunction and oxidative stress. The cellular stress induced by anabolic activity of insulin initiates an adaptive response aiming at maintaining homeostasis, characterized by activation of the transcription factor Nrf2, of AMP activated kinase, and an unfolded protein response. This protective response is more potent in the long-lived human species than in short-lived models of aging research resulting in a stronger pro-aging impact of insulin in nematodes and fruit flies. In humans, resistance to insulin-induced cell stress decreases with age, because of an increase of insulin and insulin resistance levels but less Nrf2 activation. These detrimental changes might be contained by adopting a lifestyle that promotes low insulin/insulin resistance levels and enhances an adaptive response to cellular stress, as observed with dietary restriction or exercise.

Comparison of beta-cell function between Hong Kong Chinese with young-onset type 2 diabetes and late-onset type 2 diabetes.

AIMS: We compared beta-cell function in Chinese with type 2 diabetes diagnosed at age < 40 years (young-onset diabetes, YOD) and ≥ 40 years (late-onset diabetes, LOD). METHODS: In this cross-sectional study, we selected participants from two cohorts of people with type 2 diabetes recruited in 1996-2012 (n = 4,376) and 2020-2021 (n = 794). Multivariable linear regression models were applied to compare homeostasis model assessment of beta-cell function (HOMA2-%B) and fasting plasma C-peptide across diabetes duration at enrolment between YOD and LOD. RESULTS: The YOD group (n = 1,876, mean [SD] age: 39.9 [7.5] years, median [IQR] diabetes duration: 6 [2-12] years) was more likely to have family history of diabetes (61.6 % vs 43.6 %), obesity (41.9 % vs 26.8 %), dyslipidaemia (61.7 % vs 54.4 %), and worse glycaemic control (mean HbA1c 7.7 % vs 7.4 %) than those with LOD (n = 3,294, age: 60.8 [10.6] years, diabetes duration: 5 [1-10] years). When compared to people with LOD, HOMA2-%B and fasting plasma C-peptide were lower in the YOD group, consistently among those with BMI < 27.5 kg/m2 and HOMA2-IR ≤ 1.6 (median value), adjusted for year at enrolment, sex, diabetes duration, family history of diabetes, HbA1c, weight and lipid indices (p < 0.01). Cross-sectionally, the slopes of decline in HOMA2-%B by diabetes duration were greater in YOD than LOD among individuals with BMI < 27.5 kg/m2 (p-interaction = 0.015). CONCLUSIONS: Chinese with YOD had accelerated loss of beta-cell function than those with LOD especially in non-obese individuals.

Integrative neurocircuits that control metabolism and food intake.

Systemic metabolism has to be constantly adjusted to the variance of food intake and even be prepared for anticipated changes in nutrient availability. Therefore, the brain integrates multiple homeostatic signals with numerous cues that predict future deviations in energy supply. Recently, our understanding of the neural pathways underlying these regulatory principles-as well as their convergence in the hypothalamus as the key coordinator of food intake, energy expenditure, and glucose metabolism-have been revealed. These advances have changed our view of brain-dependent control of metabolic physiology. In this Review, we discuss new concepts about how alterations in these pathways contribute to the development of prevalent metabolic diseases such as obesity and type 2 diabetes mellitus and how this emerging knowledge may provide new targets for their treatment.

Black New Yorkers with Type 2 Diabetes: Afro-Caribbean Immigrants Have Lower BMI and Lower Waist Circumference than African Americans.

OBJECTIVE: Using the 2013/2014 New York City (NYC) Health and Nutrition Examination Survey (NYCHANES) data, this exploratory study examined whether (a) type 2 diabetes (diabetes) prevalence differed between NYC Afro-Caribbeans and African Americans; (b) anthropometric, biochemical, and sociodemographic diabetes profiles differed between and within groups; and (c) diabetes odds differed between and within groups. METHODS: Diabetes was defined as prior diagnosis, HbA1c ≥ 6.5% (7.8 mmol/L), or fasting glucose ≥ 126 mg/dL. Weighted logistic regression estimated diabetes odds by nativity and either waist circumference (WC) (cm) or BMI (kg/m2). All regression models controlled for age, hypertension, gender, education, income, marital status, physical activity, and smoking. RESULTS: Among Afro-Caribbeans (n = 81, 65% female, age (mean ± SE) 49 ± 2 years, BMI 29.2 ± 0.7 kg/m2) and African Americans (n = 118, 50% female, age 47 ± 2 years, BMI 30.3 ± 0.9 kg/m2), Afro-Caribbeans with diabetes had lower BMI (29.9 ± 0.8 kg/m2 vs. 34.6 ± 1.7 kg/m2, P = 0.01) and lower WC (102 ± 2 cm vs. 114 ± 3 cm, P = 0.002) than African Americans with diabetes. Afro-Caribbeans with diabetes had lower prevalence of obesity (33.2% vs. 74.7%) and higher prevalence of overweight (57.2% vs. 13.5%) (P = 0.02) than African Americans with diabetes. Odds of diabetes did not differ between Afro-Caribbeans and African Americans. In models predicting the effect of WC, diabetes odds increased with WC (OR = 1.07 (95% CI 1.02, 1.11), P = 0.003) and age (OR = 1.09 (95% CI 1.03-1.15), P = 0.003) for African Americans only. In models predicting the effect of BMI, diabetes odds increased for Afro-Caribbeans with age (OR = 1.06 (1.01, 1.11)*, P = 0.04) and hypertension (OR = 5.62 (95% CI 1.04, 30.42), P = 0.045), whereas for African Americans, only age predicted higher diabetes odds (OR = 1.08 (95% CI 1.03, 1.14), P = 0.003). CONCLUSIONS: In NYC, Afro-Caribbeans with diabetes have lower BMI and lower WC than African Americans with diabetes, but odds of diabetes do not differ. Combining African-descent populations into one group obscures clinical differences and generalizes diabetes risk.

Liver, visceral and subcutaneous fat in men and women of South Asian and white European descent: a systematic review and meta-analysis of new and published data.

AIMS/HYPOTHESIS: South Asians have a two- to fivefold higher risk of developing type 2 diabetes than those of white European descent. Greater central adiposity and storage of fat in deeper or ectopic depots are potential contributing mechanisms. We collated existing and new data on the amount of subcutaneous (SAT), visceral (VAT) and liver fat in adults of South Asian and white European descent to provide a robust assessment of potential ethnic differences in these factors. METHODS: We performed a systematic review of the Embase and PubMed databases from inception to August 2021. Unpublished imaging data were also included. The weighted standardised mean difference (SMD) for each adiposity measure was estimated using random-effects models. The quality of the studies was assessed using the ROBINS-E tool for risk of bias and overall certainty of the evidence was assessed using the GRADE approach. The study was pre-registered with the OSF Registries ( https://osf.io/w5bf9 ). RESULTS: We summarised imaging data on SAT, VAT and liver fat from eight published and three previously unpublished datasets, including a total of 1156 South Asian and 2891 white European men, and 697 South Asian and 2271 white European women. Despite South Asian men having a mean BMI approximately 0.5-0.7 kg/m2 lower than white European men (depending on the comparison), nine studies showed 0.34 SMD (95% CI 0.12, 0.55; I2=83%) more SAT and seven studies showed 0.56 SMD (95% CI 0.14, 0.98; I2=93%) more liver fat, but nine studies had similar VAT (-0.03 SMD; 95% CI -0.24, 0.19; I2=85%) compared with their white European counterparts. South Asian women had an approximately 0.9 kg/m2 lower BMI but 0.31 SMD (95% CI 0.14, 0.48; I2=53%) more liver fat than their white European counterparts in five studies. Subcutaneous fat levels (0.03 SMD; 95% CI -0.17, 0.23; I2=72%) and VAT levels (0.04 SMD; 95% CI -0.16, 0.24; I2=71%) did not differ significantly between ethnic groups in eight studies of women. CONCLUSIONS/INTERPRETATION: South Asian men and women appear to store more ectopic fat in the liver compared with their white European counterparts with similar BMI levels. Given the emerging understanding of the importance of liver fat in diabetes pathogenesis, these findings help explain the greater diabetes risks in South Asians. FUNDING: There was no primary direct funding for undertaking the systematic review and meta-analysis.

The serum irisin response to prolonged physical activity in temperate and hot environments in older men with hypertension or type 2 diabetes.

Current labor demographics are changing, with the number of older adults increasingly engaged in physically demanding occupations expected to continually rise, which are often performed in the heat. Given an age-related decline in whole-body heat loss, older adults are at an elevated risk of developing heat injuries that may be exacerbated by hypertension (HTN) and type 2 diabetes (T2D). Elevated irisin production may play a role in mitigating the excess oxidative stress and acute inflammation associated with physically demanding work in the heat. However, the effects of HTN and T2D on this response remain unclear. Therefore, we evaluated serum irisin before and after 3-h of moderate intensity exercise (metabolic rate: 200 W/m2) and at the end of 60-min of post-exercise recovery in a temperate (wet-bulb globe temperature (WBGT) 16 °C) and high-heat stress (WBGT 32 °C) environment in 12 healthy older men (mean ± SD; 59 ± 4 years), 10 men with HTN (60 ± 4 years), and 9 men with T2D (60 ± 5 years). Core temperature (Tco) was measured continuously. In the heat, total exercise duration was significantly lower in older men with HTN and T2D (both, p ≤ 0.049). Despite Tco not being different between groups, Tco was higher in the hot compared to the temperate condition for all groups (p < 0.001). Similarly, serum irisin concentrations did not differ between groups under either condition but were elevated relative to the temperate condition during post-exercise and end-recovery in the heat (+93.9 pg/mL SEM 26 and + 70.5 pg/mL SEM 38 respectively; both p ≤ 0.014). Thus, our findings indicate similar irisin responses in HTN and T2D compared to healthy, age-matched controls, despite reduced exercise tolerance during prolonged exercise in the heat. Therefore, older workers with HTN and T2D may exhibit greater cellular stress during prolonged exercise in the heat, underlying greater vulnerability to heat-induced cellular injury.