Ethnic Similarities and Differences in the Relationship between Beta Cell Mass and Diabetes

Clinical research progress on β-cell dysfunction in T2DM development in the Chinese population

The prevalence of type-2 diabetes mellitus (T2DM) has increased over 10-fold in the past 40 years in China, which now has the largest T2DM population in the world. Insulin resistance and β-cell dysfunction are the typical features of T2DM. Although both factors play a role, decreased β-cell function and β-cell mass are the predominant factors for progression to T2DM. Considering the differences between Chinese T2DM patients and those of other ethnicities, it is important to characterize β-cell dysfunction in Chinese patients during T2DM progression. Herein, we reviewed the studies on the relationships between β-cell function and T2DM progression in the Chinese population and discussed the differences among individuals of varying ethnicities. Meanwhile, we summarized the risk factors and current treatments of T2DM in Chinese individuals and discussed their impacts on β-cell function with the hope of identifying a better T2DM therapy.

Polycystic ovary syndrome as a metabolic disease

Polycystic ovary syndrome (PCOS) is a heterogeneous familial disorder affecting up to one in five women. The aetiology remains unclear, but available evidence suggests it is a polygenic disorder with epigenetic, developmental, and environmental components. The diagnostic criteria for PCOS are based on reproductive features, and the syndrome is categorized into several phenotypes that can vary by race and ethnicity. Insulin resistance and metabolic dysfunction have a crucial role in the pathogenesis of the syndrome and contribute to many adverse metabolic outcomes that place a substantial burden on the health of women with PCOS across their lifespan. Metabolic abnormalities like those identified in women with PCOS are also present in their female and male first-degree relatives. Overall, more emphasis is required on defining PCOS as a metabolic disorder in addition to a reproductive one. This approach could affect the management and future treatment options for the syndrome. The rationale of the current review is to identify and analyse existing evidence for PCOS as a metabolic, as well as a reproductive, disease.

Clinical application of cluster analysis in patients with newly diagnosed type 2 diabetes

AIMS

Early prevention and treatment of type 2 diabetes mellitus (T2DM) is still a huge challenge for patients and clinicians. Recently, a novel cluster-based diabetes classification was proposed which may offer the possibility to solve this problem. In this study, we report our performance of cluster analysis of individuals newly diagnosed with T2DM, our exploration of each subtype's clinical characteristics and medication treatment, and the comparison carried out concerning the risk for diabetes complications and comorbidities among subtypes by adjusting for influencing factors. We hope to promote the further application of cluster analysis in individuals with early-stage T2DM.

METHODS

In this study, a k-means cluster algorithm was applied based on five indicators, namely, age, body mass index (BMI), glycosylated hemoglobin (HbA1c), homeostasis model assessment-2 insulin resistance (HOMA2-IR), and homeostasis model assessment-2 β-cell function (HOMA2-β), in order to perform the cluster analysis among 567 newly diagnosed participants with T2DM. The clinical characteristics and medication of each subtype were analyzed. The risk for diabetes complications and comorbidities in each subtype was compared by logistic regression analysis.

RESULTS

The 567 patients were clustered into four subtypes, as follows: severe insulin-deficient diabetes (SIDD, 24.46%), age-related diabetes (MARD, 30.86%), mild obesity-related diabetes (MOD, 25.57%), and severe insulin-resistant diabetes (SIRD, 20.11%). According to the results of the oral glucose tolerance test (OGTT) and biochemical indices, fasting blood glucose (FBG), 2-hour postprandial blood glucose (2hBG), HbA1c, total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and triglyceride-glucose index (TyG) were higher in SIDD and SIRD than in MARD and MOD. MOD had the highest fasting C-peptide (FCP), 2-hour postprandial C-peptide (2hCP), fasting insulin (FINS), 2-hour postprandial insulin (2hINS), serum creatinine (SCr), and uric acid (UA), while SIRD had the highest triglycerides (TGs) and TyG-BMI. Albumin transaminase (ALT) and albumin transaminase (AST) were higher in MOD and SIRD. As concerms medications, compared to the other subtypes, SIDD had a lower rate of metformin use (39.1%) and a higher rate of α-glucosidase inhibitor (AGI, 61.7%) and insulin (74.4%) use. SIRD showed the highest frequency of use of sodium-glucose cotransporter-2 inhibitors (SGLT-2i, 36.0%) and glucagon-like peptide-1 receptor agonists (GLP-1RA, 19.3%). Concerning diabetic complications and comorbidities, the prevalence of diabetic kidney disease (DKD), cardiovascular disease (CVD), non-alcoholic fatty liver disease (NAFLD), dyslipidemia, and hypertension differed significantly among subtypes. Employing logistic regression analysis, after adjusting for unmodifiable (sex and age) and modifiable related influences (e.g., BMI, HbA1c, and smoking), it was found that SIRD had the highest risk of developing DKD (odds ratio, OR = 2.001, 95% confidence interval (CI): 1.125-3.559) and dyslipidemia (OR = 3.550, 95% CI: 1.534-8.215). MOD was more likely to suffer from NAFLD (OR = 3.301, 95%CI: 1.586-6.870).

CONCLUSIONS

Patients with newly diagnosed T2DM can be successfully clustered into four subtypes with different clinical characteristics, medication treatment, and risks for diabetes-related complications and comorbidities, the cluster-based diabetes classification possibly being beneficial both for prevention of secondary diabetes and for establishment of a theoretical basis for precision medicine.

NPYR modulation: Potential for the next major advance in obesity and type 2 diabetes management?

The approval of the glucagon-like peptide 1 (GLP-1) mimetics semaglutide and liraglutide for management of obesity, independent of type 2 diabetes (T2DM), has initiated a resurgence of interest in gut-hormone derived peptide therapies for the management of metabolic diseases, but side-effect profile is a concern for these medicines. However, the recent approval of tirzepatide for obesity and T2DM, a glucose-dependent insulinotropic polypeptide (GIP), GLP-1 receptor co-agonist peptide therapy, may provide a somewhat more tolerable option. Despite this, an increasing number of non-incretin alternative peptides are in development for obesity, and it stands to reason that other hormones will take to the limelight in the coming years, such as peptides from the neuropeptide Y family. This narrative review outlines the therapeutic promise of the neuropeptide Y family of peptides, comprising of the 36 amino acid polypeptides neuropeptide Y (NPY), peptide tyrosine-tyrosine (PYY) and pancreatic polypeptide (PP), as well as their derivatives. This family of peptides exerts a number of metabolically relevant effects such as appetite regulation and can influence pancreatic beta-cell survival. Although some of these actions still require full translation to the human setting, potential therapeutic application in obesity and type 2 diabetes is conceivable. However, like GLP-1 and GIP, the endogenous NPY, PYY and PP peptide forms are subject to rapid in vivo degradation and inactivation by the serine peptidase, dipeptidyl-peptidase 4 (DPP-4), and hence require structural modification to prolong circulating half-life. Numerous protective modification strategies are discussed in this regard herein, alongside related impact on biological activity profile and therapeutic promise.

Polygenic Variants Linked to Oxidative Stress and the Antioxidant System Are Associated with Type 2 Diabetes Risk and Interact with Lifestyle Factors

Oxidative stress is associated with insulin resistance and secretion, and antioxidant systems are essential for preventing and managing type 2 diabetes (T2DM). This study aimed to explore the polygenic variants linked to oxidative stress and the antioxidant system among those associated with T2DM and the interaction of their polygenic risk scores (PRSs) with lifestyle factors in a large hospital-based cohort (n = 58,701). Genotyping, anthropometric, biochemical, and dietary assessments were conducted for all participants with an average body mass index of 23.9 kg/m2. Genetic variants associated with T2DM were searched through genome-wide association studies in participants with T2DM (n = 5383) and without T2DM (n = 53,318). The Gene Ontology database was searched for the antioxidant systems and oxidative stress-related genes among the genetic variants associated with T2DM risk, and the PRS was generated by summing the risk alleles of selected ones. Gene expression according to the genetic variant alleles was determined on the FUMA website. Food components with low binding energy to the GSTA5 protein generated from the wildtype and mutated GSTA5_rs7739421 (missense mutation) genes were selected using in silico analysis. Glutathione metabolism-related genes, including glutathione peroxidase (GPX)1 and GPX3, glutathione disulfide reductase (GSR), peroxiredoxin-6 (PRDX6), glutamate-cysteine ligase catalytic subunit (GCLC), glutathione S-transferase alpha-5 (GSTA5), and gamma-glutamyltransferase-1 (GGT1), were predominantly selected with a relevance score of >7. The PRS related to the antioxidant system was positively associated with T2DM (ORs = 1.423, 95% CI = 1.22-1.66). The active site of the GASTA proteins having valine or leucine at 55 due to the missense mutation (rs7739421) had a low binding energy (<-10 kcal/mol) similarly or differently to some flavonoids and anthocyanins. The PRS interacted with the intake of bioactive components (specifically dietary antioxidants, vitamin C, vitamin D, and coffee) and smoking status (p < 0.05). In conclusion, individuals with a higher PRS related to the antioxidant system may have an increased risk of T2DM, and there is a potential indication that exogenous antioxidant intake may alleviate this risk, providing insights for personalized strategies in T2DM prevention.

Increased risk of incident diabetes after therapy with immune checkpoint inhibitor compared with conventional chemotherapy: A longitudinal trajectory analysis using a tertiary care hospital database

AIMS/HYPOTHESIS

Immune checkpoint inhibitor (ICI) has been emerged as a promising cancer treatment. However, ICI use induces immune-related adverse events, including diabetes mellitus. We compared the risk of new-onset diabetes between patients receiving an ICI and those receiving conventional chemotherapy (CC).

METHODS

Using a tertiary care hospital database, we included cancer patients without a previous history of diabetes who were treated with either CC or an ICI. One-to-five nearest neighbor propensity matching was applied, and the risk of diabetes was estimated using a Cox proportional hazards model. Latent class growth modeling was performed with a trajectory approach to determine distinct clusters that followed similar glucose trajectory patterns over time.

RESULTS

Among 1326 subjects, 1105 received CC, and 221 received an ICI. The risk of new-onset diabetes was significantly higher in the ICI group than the CC group (adjusted hazard ratio 2.454, 95 % confidence interval 1.528-3.940; p < 0.001). The ICI group had a higher proportion of subjects in the trajectory cluster with an increasing glucose pattern than the CC group (10.4 % and 7.4 %, respectively). Within the ICI group, the subjects with an increasing glucose pattern were predominantly male and associated with enhanced lymphocytosis after ICI administration.

CONCLUSIONS

ICI therapy is associated with an increased risk of incident diabetes compared with CC. The glucose levels of patients treated with an ICI, especially males and those with prominent lymphocytosis after ICI treatment, need to be monitored regularly to detect ICI-associated diabetes as early as possible.

Simultaneous Versus Sequential Initiation of Lixisenatide and Basal Insulin for Type 2 Diabetes: Subgroup Analysis of a Japanese Post-Marketing Surveillance Study of Lixisenatide (PRANDIAL)

INTRODUCTION

We aimed to assess the efficacy and safety of lixisenatide and basal insulin (BI) according to timing of treatment initiation, treatment compliance, and number of concomitant daily injections in Japanese individuals with type 2 diabetes (T2D).

METHODS

Each substudy analyzed subgroup data from the 3-year post-marketing surveillance PRANDIAL study. Endpoints included glycated hemoglobin (HbA1c), postprandial glucose, treatment response (HbA1c < 7.0% at week 24 and 156), and safety. Changes in HbA1c levels were analyzed using paired t tests; between-group comparisons were made using analysis of variance (ANOVA).

RESULTS

Of 2679 participants, 46.5% initiated BI before lixisenatide, 12.0% the same day, 2.7% between 1 and 90 days, and 2.8% at 91 or more days after lixisenatide; 36.0% did not receive BI. Overall, 85.4% of patients were compliant with lixisenatide treatment. The majority of patients (52.4%) received two injections/day (one was lixisenatide). Compared with other subgroups taking BI and lixisenatide, the subgroup starting them simultaneously had a mean change in HbA1c of - 0.69% [8 mmol/mol] (vs + 0.07% [0.8 mmol/mol] to - 0.79% [9 mmol/mol]) and numerically higher treatment response (21.0% vs 8.3-18.7%), but more hypoglycemia (8.1% vs 2.3-2.8%).

CONCLUSIONS

Japanese people with T2D achieved better glycemic control by simultaneous as opposed to sequential initiation of lixisenatide and BI.

Association between circulating SerpinB1 levels and insulin sensitivity in Japanese with type 2 diabetes: A single-center, cross-sectional, observational study

Plasma and liver SerpinB1 levels are elevated in mice with insulin resistance and promote β-cell proliferation in human islets. We measured serum SerpinB1 levels in Japanese subjects with or without type 2 diabetes (T2DM). We enrolled 12 normal glucose tolerance (NGT) and 51 T2DM subjects. There was no difference in serum SerpinB1 levels between the 2 groups (T2DM, 1.3 ± 0.9 ng/mL vs. NGT, 1.8 ± 1.7 ng/mL; P = 0.146). After adjusting for age and sex, the serum SerpinB1 levels were positively correlated with HOMA2-%S (β = 0.319, P = 0.036), and negatively correlated with fasting blood glucose (β = -0.365, P = 0.010), total cholesterol (β = -0.396, P = 0.006), low-density lipoprotein (LDL) cholesterol (β = -0.411, P = 0.004), triglycerides (β = -0.321, P = 0.026), and γGTP (β = -0.322, P = 0.026) in subjects with T2DM. Thus, circulating SerpinB1 is possibly associated with insulin sensitivity and better blood glucose level in Japanese subjects with T2DM.

Trial registration: UMIN Clinical Trials Registry, UMIN000020453.

Use of c-peptide as a measure of cephalic phase insulin release in humans

Cephalic phase insulin release (CPIR) is a rapid pulse of insulin secreted within minutes of food-related sensory stimulation. Understanding the mechanisms underlying CPIR in humans has been hindered by its small observed effect size and high variability within and between studies. One contributing factor to these limitations may be the use of peripherally measured insulin as an indicator of secreted insulin, since a substantial portion of insulin is metabolized by the liver before delivery to peripheral circulation. Here, we investigated the use of c-peptide, which is co-secreted in equimolar amounts to insulin from pancreatic beta cells, as a proxy for insulin secretion during the cephalic phase period. Changes in insulin and c-peptide were monitored in 18 adults over two repeated sessions following oral stimulation with a sucrose-containing gelatin stimulus. We found that, on average, insulin and c-peptide release followed a similar time course over the cephalic phase period, but that c-peptide showed a greater effect size. Importantly, when insulin and c-peptide concentrations were compared across sessions, we found that changes in c-peptide were significantly correlated at the 2 min (r = 0.50, p = 0.03) and 4 min (r = 0.65, p = 0.003) time points, as well as when participants' highest c-peptide concentrations were considered (r = 0.64, p = 0.004). In contrast, no significant correlations were observed for changes in insulin measured from the sessions (r = -0.06-0.35, p > 0.05). Herein, we detail the individual variability of insulin and c-peptide concentrations measured during the cephalic phase period, and identify c-peptide as a valuable metric for insulin secretion alongside insulin concentrations when investigating CPIR.

Expert Opinion on Diabetes Management Challenges and Role of Basal Insulin/GLP-1 RA Fixed-Ratio Combination in People with Type 2 Diabetes from Indonesia

Indonesia is struggling with a rapidly growing burden of diabetes due to rapid socioeconomic transition. People with type 2 diabetes mellitus (T2DM) need appropriate treatment strategies to maintain glycemic control. New modalities with simplicity, such as fixed-ratio combination of basal insulin and glucagon-like peptide-1 receptor agonist (GLP-1 RA), further referred to as FRC, have proven to be an effective and practical therapeutic approach that may address this issue. In January 2021, a scientific expert meeting was held with the participation of endocrinologists from Indonesia to provide expert opinions regarding the optimal practical use of the FRC basal insulin/GLP1-RA. Topics discussed in the meeting included the challenges in diabetes management, clinical inertia with insulin therapy, local and international guideline positioning, initiation, titration, and switching of basal insulin and GLP-1 RA, including FRC, and the management of T2DM.

Association of Polygenic Variants with Type 2 Diabetes Risk and Their Interaction with Lifestyles in Asians

Over the last several decades, there has been a considerable growth in type 2 diabetes (T2DM) in Asians. A pathophysiological mechanism in Asian T2DM is closely linked to low insulin secretion, β-cell mass, and inability to compensate for insulin resistance. We hypothesized that genetic variants associated with lower β-cell mass and function and their combination with unhealthy lifestyle factors significantly raise T2DM risk among Asians. This hypothesis was explored with participants aged over 40. Participants were categorized into T2DM (case; n = 5383) and control (n = 53,318) groups. The genetic variants associated with a higher risk of T2DM were selected from a genome-wide association study in a city hospital-based cohort, and they were confirmed with a replicate study in Ansan/Ansung plus rural cohorts. The interacted genetic variants were identified with generalized multifactor dimensionality reduction analysis, and the polygenic risk score (PRS)-nutrient interactions were examined. The 8-SNP model was positively associated with T2DM risk by about 10 times, exhibiting a higher association than the 20-SNP model, including all T2DM-linked SNPs with p < 5 × 10−6. The SNPs in the models were primarily involved in pancreatic β-cell growth and survival. The PRS of the 8-SNP model interacted with three lifestyle factors: energy intake based on the estimated energy requirement (EER), Western-style diet (WSD), and smoking status. Fasting serum glucose concentrations were much higher in the participants with High-PRS in rather low EER intake and high-WSD compared to the High-EER and Low-WSD, respectively. They were shown to be higher in the participants with High-PRS in smokers than in non-smokers. In conclusion, the genetic impact of T2DM risk was mainly involved with regulating pancreatic β-cell mass and function, and the PRS interacted with lifestyles. These results highlight the interaction between genetic impacts and lifestyles in precision nutrition.

The Association of Gestational Diabetes with HIV Infection and Tuberculosis in Indian Women

Infection of HIV is associated with an increased diabetes risk, which also increases tuberculosis risk. It is unknown if similar associations exist with gestational diabetes (GDM). We screened pregnant women living with and without HIV for GDM using oral glucose tolerance testing. In a subgroup of women with latent tuberculosis (positive interferon-gamma [IFN-γ] release assay), we used supernatants from tuberculosis antigen tubes to compare cytokine levels from women with and without GDM, matched by age and HIV status. Of 234 women, 21 (9%) had GDM, 13.9% living with HIV, and 6.5% without HIV (P = 0.06). Compared with women without GDM, women with GDM had lower median IFN-γ (19.1 versus 141.9 pg/mL, P = 0.03) and interleukin-2 (18.7 versus 249 pg/mL, P < 0.01). Our study suggests that HIV infection is associated with an increased risk of GDM, which is associated with decreased Mycobacterium tuberculosis immune responses. Gestational diabetes screening should be prioritized in tuberculosis-endemic countries, especially in women living with HIV.

The Durable Safety and Effectiveness of Lixisenatide in Japanese People with Type 2 Diabetes: The Post-Marketing Surveillance PRANDIAL Study

Introduction

Real-world evidence on lixisenatide in Japanese people with type 2 diabetes (T2D) is lacking. Therefore, the 3-year post-marketing PRANDIAL study was conducted to evaluate the safety (primary objective) and effectiveness (secondary objective) of lixisenatide in Japanese people with T2D during routine clinical practice.

Methods

This prospective, observational, multicenter, open-label study was conducted in Japanese individuals with T2D who initiated lixisenatide treatment between March 2014 and June 2017. Using electronic case report forms, investigators collected baseline demographic and clinical information and data on medications, safety and effectiveness up to 3 years after initiation of lixisenatide.

Results

Overall, 3046 participants were analyzed; their mean ± standard deviation (SD) age was 58.9 ± 13.1 years, and 53.7% were male. Mean ± SD duration of T2D was 12.8 ± 8.6 years, and baseline glycated hemoglobin (HbA1c) was 8.7% ± 1.7%. Most participants (93.9%) were receiving concomitant antidiabetic medications when they initiated lixisenatide. Median (range) lixisenatide treatment duration was 382 (1–1096) days. Adverse drug reactions (ADRs) were reported in 604 participants (19.8%) and serious ADRs in 22 (0.7%). The most common ADR was nausea (9.0%). Of ADRs of special interest, hypoglycemia occurred in 2.9% of participants, injection site reactions in 0.9%, and hypoglycemic unconsciousness in 0.03%. Baseline characteristics associated with an increased risk of ADRs (p < 0.05) were history of treatment for cardiovascular disease, hepatic dysfunction, and other complications. Effectiveness was analyzed in 2675 participants; HbA1c, fasting plasma glucose, postprandial glucose, and body weight all decreased significantly at last observation (all p < 0.0001 vs. baseline).

Conclusions

Lixisenatide was well tolerated, with no unexpected ADRs or new safety signals identified, and showed effective glycemic control and weight reduction up to 3 years, supporting the use of lixisenatide as a safe and effective treatment option for T2D in routine clinical practice in Japan.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12325-022-02121-5.

Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are antidiabetic drugs that lower blood glucose levels by stimulating the release of insulin and suppressing glucagon, the key hormones involved in controlling blood glucose levels in the body. The selective GLP-1RA lixisenatide was approved for the management of adults with type 2 diabetes (T2D) in Japan based on data from randomized clinical trials. However, these studies may not be representative of the safety and effectiveness of the drug when used in routine clinical practice. Therefore, we conducted the 3-year post-marketing PRANDIAL study to assess the safety and effectiveness of lixisenatide in 3046 Japanese individuals with T2D who started the drug between March 2014 and June 2017. Adverse drug reactions (adverse events for which lixisenatide causality could not be excluded) occurred in 19.8% of participants, with the most common adverse drug reaction being nausea. Hypoglycemia (abnormally low blood glucose levels) was reported in 2.9%. Individuals with a history of treatment for cardiovascular disease, hepatic dysfunction, and other complications had an increased risk of adverse drug reactions. Lixisenatide provided significant improvements in blood glucose control, with significant decreases in glycated hemoglobin (a marker of blood glucose control), fasting plasma glucose, and postprandial glucose levels from baseline, as well as significant reductions in body weight. In this real-world post-marketing surveillance study, lixisenatide was well tolerated, raising no new safety concerns, and provided durable effective blood glucose control and weight reduction. These results support the use of lixisenatide in Japanese individuals with T2D in routine clinical practice.

Dynamic assessment of insulin secretion and insulin resistance in Asians with prediabetes

AIMS/HYPOTHESIS

Prediabetes and type 2 diabetes are highly prevalent in Asia. Understanding the pathophysiology of abnormal glucose homeostasis in Asians will have important implications for reducing disease burden, but there have been conflicting reports on the relative contributions of insulin secretion and action in disease progression. In this study, we aimed to assess the contribution of β-cell dysfunction and insulin resistance in the Asian prediabetes phenotype.

METHODS

We recruited 1679 Asians with prediabetes (n = 659) or normoglycemia (n = 1020) from a multi-ethnic population in Singapore. Participants underwent an oral glucose tolerance test, an intravenous glucose challenge, and a hyperinsulinemic-euglycemic clamp procedure to determine glucose tolerance, β-cell responsivity, insulin secretion, insulin clearance and insulin sensitivity.

RESULTS

Participants with prediabetes had significantly higher glucose concentrations in the fasting state and after glucose ingestion than did normoglycemic participants. Insulin sensitivity (M/I ratio) was ~15% lower, acute insulin response (AIR) to intravenous glucose and β-cell responsivity to oral glucose were ~35% lower, but total insulin secretion rate in the fasting state and after glucose ingestion was ~10% greater in prediabetic than in normoglycemic participants. The decrease in β-cell function with worsening glucose homeostasis in Asians with prediabetes was associated with progressively greater defects in AIR rather than M/I. However, analysis using static surrogate measures (HOMA indices) of insulin resistance and β-cell function revealed a different pattern.

CONCLUSIONS

Lower AIR to intravenous glucose and β-cell responsivity to oral glucose, on a background of mild insulin resistance, are the major contributors to the dysregulation of glucose homeostasis in Asians with prediabetes.

iGlarLixi reduces residual hyperglycemia in Japanese patients with type 2 diabetes uncontrolled on basal insulin: A post-hoc analysis of the LixiLan JP-L trial

INTRODUCTION

Treatments for type 2 diabetes targeting baseline glucose levels but not postprandial glucose can result in normalized fasting blood glucose but suboptimal overall glycemic control (high glycated hemoglobin): residual hyperglycemia. In Japanese patients with type 2 diabetes the predominant pathophysiology is a lower insulin secretory capacity, and residual hyperglycemia is common with basal insulin treatment. Single-injection, fixed-ratio combinations of glucagon-like peptide-1 receptor agonists and basal insulin have been developed. iGlarLixi (insulin glargine 100 units/mL [iGlar]: lixisenatide ratio of 1 unit:1 µg) is for specific use in Japan. Post-hoc analysis of the LixiLan JP-L trial (NCT02752412) compared the effect of iGlarLixi with iGlar on this specific subpopulation with residual hyperglycemia.

MATERIALS AND METHODS

Outcomes at week 26 (based on the last observation carried forward) were assessed in patients in the modified intent-to-treat population with baseline residual hyperglycemia.

RESULTS

Overall, 83 (32.5%) patients in the iGlarLixi group and 79 (30.7%) patients in the iGlar group had baseline residual hyperglycemia. The proportion of patients with residual hyperglycemia at week 26 decreased to 15.7% in the iGlarLixi group, and increased to 36.9% in the iGlar group. Patients in the iGlarLixi group had significantly greater reductions in glycated hemoglobin compared with the iGlar group (-0.72% difference between groups; P < 0.0001).

CONCLUSIONS

New data from this post-hoc analysis of the JP-L trial show that treatment with the fixed-ratio combination iGlarLixi reduced the proportion of Japanese patients with residual hyperglycemia from baseline to week 26 and significantly reduced glycated hemoglobin vs similar doses of iGlar alone.

Revisiting Regulators of Human β-cell Mass to Achieve β-cell-centric Approach Toward Type 2 Diabetes

Type 2 diabetes (T2DM) is characterized by insulin resistance and β-cell dysfunction. Because patients with T2DM have inadequate β-cell mass (BCM) and β-cell dysfunction worsens glycemic control and makes treatment difficult, therapeutic strategies to preserve and restore BCM are needed. In rodent models, obesity increases BCM about 3-fold, but the increase in BCM in humans is limited. Besides, obesity-induced changes in BCM may show racial differences between East Asians and Caucasians. Recently, the developmental origins of health and disease hypothesis, which states that the risk of developing noncommunicable diseases including T2DM is influenced by the fetal environment, has been proposed. It is known in rodents that animals with low birthweight have reduced BCM through epigenetic modifications, making them more susceptible to diabetes in the future. Similarly, in humans, we revealed that individuals born with low birthweight have lower BCM in adulthood. Because β-cell replication is more frequently observed in the 5 years after birth, and β cells are found to be more plastic in that period, a history of childhood obesity increases BCM. BCM in patients with T2DM is reduced by 20% to 65% compared with that in individuals without T2DM. However, since BCM starts to decrease from the stage of borderline diabetes, early intervention is essential for β-cell protection. In this review, we summarize the current knowledge on regulatory factors of human BCM in health and diabetes and propose the β-cell–centric concept of diabetes to enhance a more pathophysiology-based treatment approach for T2DM.

Aqueous Blackcurrant Extract Improves Insulin Sensitivity and Secretion and Modulates the Gut Microbiome in Non-Obese Type 2 Diabetic Rats

This study was undertaken to determine whether aqueous blackcurrant extracts (BC) improve glucose metabolism and gut microbiomes in non-obese type 2 diabetic animals fed a high-fat diet and to identify the mechanism involved. Partially pancreatectomized male Sprague–Dawley rats were provided a high-fat diet containing 0% (control), 0.2% (L-BC; low dosage), 0.6% (M-BC; medium dosage), and 1.8% (H-BC; high dosage) blackcurrant extracts; 0.2% metformin (positive-C); plus 1.8%, 1.6%, 1.2%, 0%, and 1.6% dextrin, specifically indigestible dextrin, daily for 8 weeks. Daily blackcurrant extract intakes were equivalent to 100, 300, and 900 mg/kg body weight (bw). After a 2 g glucose or maltose/kg bw challenge, serum glucose and insulin concentrations during peak and final states were obviously lower in the M-BC and H-BC groups than in the control group (p < 0.05). Intraperitoneal insulin tolerance testing showed that M-BC and H-BC improved insulin resistance. Hepatic triglyceride deposition, TNF-α expression, and malondialdehyde contents were lower in the M-BC and H-BC groups than in the control group. Improvements in insulin resistance in the M-BC and H-BC groups were associated with reduced inflammation and oxidative stress (p < 0.05). Hyperglycemic clamp testing showed that insulin secretion capacity increased in the acute phase (2 to 10 min) in the M-BC and H-BC groups and that insulin sensitivity in the hyperglycemic state was greater in these groups than in the control group (p < 0.05). Pancreatic β-cell mass was greater in the M-BC, H-BC, and positive-C groups than in the control group. Furthermore, β-cell proliferation appeared to be elevated and apoptosis was suppressed in these three groups (p < 0.05). Serum propionate and butyrate concentrations were higher in the M-BC and H-BC groups than in the control group. BC dose-dependently increased α-diversity of the gut microbiota and predicted the enhancement of oxidative phosphorylation-related microbiome genes and downregulation of carbohydrate digestion and absorption-related genes, as determined by PICRUSt2 analysis. In conclusion, BC enhanced insulin sensitivity and glucose-stimulated insulin secretion, which improved glucose homeostasis, and these improvements were associated with an incremental increase of the α-diversity of gut microbiota and suppressed inflammation and oxidative stress.

Fixed-ratio combination of basal insulin and glucagon-like peptide-1 receptor agonists in the treatment of Japanese people with type 2 diabetes: An innovative solution to a complex therapeutic challenge

Over 10 million people in Japan have known or suspected type 2 diabetes (T2D), and this number is expected to rise. Although many people require therapy escalation because of the progressive nature of T2D, this appears to be suboptimal in Japanese real-world clinical practice. Insulin therapy tends to be introduced only when glycaemic control is very poor (mean glycated haemoglobin >9%). Although basal insulin therapy is effective in reducing fasting plasma glucose (FPG), postprandial plasma glucose often remains uncontrolled. Basal-bolus insulin regimens are complex and carry the risk of weight gain and hypoglycaemia. Recently, fixed-ratio combinations (FRCs) of BI and glucagon-like peptide-1 receptor agonists (GLP-1RAs) have shown efficacy in reducing both FPG and postprandial plasma glucose with a single injection and without increased risk of hypoglycaemia or weight gain. IDegLira, a titratable FRC of insulin degludec (100 U/mL) and liraglutide, is currently available in Japan and the United States/European Union at a ratio of 1 U (unit):0.036 mg. iGlarLixi (insulin glargine 100 U/mL and lixisenatide at a ratio of 1:1 (20 U/20 μg) has recently been approved in Japan. Phase 3 trials in Japan for IDegLira (DUAL Japan) and iGlarLixi (LixiLan JP) have shown that both FRCs are efficacious. This review provides an overview of IDegLira and iGlarLixi (Japanese formulation) and considers their potential use as new therapeutic options to address the clinical need for early glycaemic control in Japanese people with T2D.

Benefits of the fixed-ratio combination of insulin glargine 100 units/mL and lixisenatide (iGlarLixi) in Japanese people with type 2 diabetes: A subgroup and time-to-control analysis of the LixiLan JP phase 3 trials

AIMS

To explore the impact of baseline characteristics on clinical outcomes in the phase 3 LixiLan JP trials which evaluated the efficacy and safety of iGlarLixi, a titratable fixed-ratio combination of insulin glargine 100 units/mL (iGlar) and GLP-1 RA lixisenatide (Lixi), vs Lixi (JP-O1, NCT02749890) or iGlar (LixiLan JP-O2, NCT02752828; JP-L, NCT02752412) in Japanese people with type 2 diabetes uncontrolled on oral antidiabetes drugs (OADs; JP-O1, JP-O2) or OADs and basal insulin (JP-L).

MATERIALS AND METHODS

Glycated haemoglobin (HbA1c) change from baseline to week 26 was assessed within patient subgroups. Subgroups were defined by dipeptidyl peptidase-4 inhibitor use at screening (JP-O1, JP-O2 only), baseline HbA1c (<8%, ≥8%), baseline BMI (<25, ≥25 kg/m²) and age (<65, ≥65 years). Incidences of hypoglycaemia (baseline HbA1c, BMI and age subgroups) and gastrointestinal disorders (age subgroup) were evaluated over 52 (JP-O1) or 26 weeks (JP-O2, JP-L). Time to control (first HbA1c <7% or fasting plasma glucose [FPG] ≤130 mg/dL; JP-O2 only) was also assessed.

RESULTS

HbA1c reductions were consistently greater with iGlarLixi vs iGlar or Lixi across all subgroups, and iGlarLixi was equally effective in all subgroups. Incidences of documented symptomatic hypoglycaemia (plasma glucose ≤3.9 mmol/L) were higher with iGlarLixi vs Lixi and generally comparable with iGlar. Across age subgroups, incidences of gastrointestinal disorders with iGlarLixi were higher vs iGlar, but lower vs Lixi. Median time to HbA1c or FPG control was shorter with iGlarLixi vs iGlar.

CONCLUSIONS

iGlarLixi was consistently effective across all baseline characteristic subgroups, with more patients achieving glycaemic control vs iGlar early in treatment.

Racial and ethnic differences in the metabolic response of polycystic ovary syndrome

CONTEXT

Polycystic ovary syndrome (PCOS) is a highly prevalent disorder associated with insulin resistance (IR) and compensatory hyperinsulinemia. Although variations in cardiometabolic risks across race and ethnicities have been reported in the general population, racial/ethnic disparities in the metabolic dysfunction of PCOS remain relatively unstudied.

OBJECTIVES

To determine whether markers of metabolic function differ in nondiabetic Asian American (AS), African American (AA), Hispanic White (HW), compared to non-Hispanic White (NHW) women with PCOS.

DESIGN AND SETTING

Prospective cross-sectional study in a tertiary institution.

PARTICIPANTS AND INTERVENTIONS

A total of 259 nondiabetic women with PCOS (by NIH 1990 criteria) who completed a 2-hour 75-g oral glucose tolerance test measuring plasma glucose and insulin levels. Basal IR and insulin secretion, assessed by the homeostasis model assessment (HOMA-IR and HOMA-β%, respectively), and two-hour hyperglycaemia and hyperinsulinemia after an oral glucose load, were compared in 21 AS, 24 AA, 53 HW and 161 NHW consecutive nondiabetic adult PCOS women.

RESULTS

After adjusting for age and body mass index, HW and AA PCOS women demonstrated higher fasting and post-glucose challenge insulin levels, and higher HOMA-IR and HOMA-β%, than NHW women, although glucose levels were similar. In contrast, AS PCOS women had or tended to have lower HOMA-β% than any other racial/ethnic groups, lower HOMA-IR, and fasting and post-challenge insulin levels than AA or HW, and also had higher (albeit still normal) mean post-challenge glucose levels than NHW women with PCOS despite similar HOMA-IR, and fasting insulin and post-challenge insulin levels. Waist-hip ratio was similar across the four groups.

CONCLUSION

Both HW and AA women with PCOS have increased basal state IR and higher β-cell response, and post-challenge hyperinsulinemia compared to NHW and AS subjects. The trend towards a lesser insulin response among Asian women requires further investigation. These findings suggest that the screening and management of metabolic dysfunction in PCOS should consider patients' race/ethnicity.

Changing the Concept of Type 2 Diabetes: Beta Cell Workload Hypothesis Revisited

BACKGROUND

Despite a number of innovations in anti-diabetic drugs and substantial improvement in diabetes care, the number of people with diabetes continues to increase, suggesting further need to explore novel approaches to prevent diabetes. Type 2 diabetes (T2DM) is characterized by beta cell dysfunction and insulin resistance. However, insulin resistance, usually a consequence of obesity, is often emphasized and the role of beta cell dysfunction in T2DM is less appreciated.

OBJECTIVE AND RESULTS

This paper summarizes recent evidence showing the importance of beta cell dysfunction in T2DM and refines the "beta cell workload hypothesis", emphasizing the importance of beta cell preservation for the prevention and management of T2DM.

CONCLUSION

It is hoped that this novel concept will foster a better understanding of the pathophysiology of T2DM by not only medical staff and patients with diabetes, but also the general population, and encourage more people to adhere to a healthy lifestyle, eventually resulting in "stopping diabetes".

Teneligliptin versus sitagliptin in Korean patients with type 2 diabetes inadequately controlled with metformin and glimepiride: A randomized, double-blind, non-inferiority trial

AIM

To assess the efficacy and safety of add-on therapy with the dipeptidyl peptidase-4 inhibitor teneligliptin compared with sitagliptin in patients with type 2 diabetes (T2DM) inadequately controlled with metformin and glimepiride.

MATERIALS AND METHODS

This was a phase 3, randomized, double-blind, non-inferiority study of adult Korean subjects with T2DM (n = 201), with HbA1c ranging from 7.0% to 11.0%, on stable doses of metformin plus glimepiride. Subjects were randomized in a 1:1 fashion to receive either oral teneligliptin 20 mg or sitagliptin 100 mg for 24 weeks. The primary endpoint was change from baseline in HbA1c.

RESULTS

At baseline, mean age was 60.56 ± 9.41 years, body mass index was 25.23 ± 2.85 kg/m² and HbA1c was 8.11% ± 0.79%. At 24 weeks, both groups achieved significant reductions from baseline in HbA1c (teneligliptin, -1.03% ± 0.10% [P < 0.0001]; sitagliptin, -1.02% ± 0.10% [P < 0.0001]). The inter-group difference was -0.01% (95% confidence interval [CI]: -0.28, 0.26; P = 0.9497); the upper limit of the 95% CI was within the preset limit for non-inferiority (0.4%). There were no significant differences between groups in the proportion of patients achieving HbA1c targets, or changes from baseline in fasting plasma glucose, body weight or lipid levels at 24 weeks. Rates of adverse events (teneligliptin, n = 63 [61.76%]; sitagliptin, n = 61 [62.24%]; P = 0.9442) and hypoglycaemia (teneligliptin, n = 32 [31.37%]; sitagliptin, n = 28 [28.57%]; P = 0.6656) were similar.

CONCLUSION

Teneligliptin was non-inferior to sitagliptin in the context of triple therapy for T2DM and is an important option in this setting.

Regional variation of human pancreatic islets dimension and its impact on beta cells in Indian population

Background & objectives: Islet of Langerhans, the endocrine pancreas plays a significant role in glucose metabolism. Obesity and insulin resistance are the major factors responsible for beta cell dysfunction. Asian Indian population has increased susceptibility to diabetes in spite of having lower BMI. The morphology of islets plays a significant role in beta cell function. The present study was designed for better understanding the morphology, composition and distribution of islets in different parts of the pancreas and its impact on beta cell proportion. Methods: We observed islet morphology and beta cell area proportion by Large-scale computer-assisted analysis in 20 adult human pancreases in non-diabetic Indian population. Immunohistochemical staining with anti-synaptophysin and anti-insulin antibody was used to detect islet and beta cells respectively. Whole slide images were analyzed using ImageJ software. Results: Endocrine proportion were heterogeneously increasing from head to tail with maximum islet and beta cell distribution in the tail region. Larger islets were predominately confined to the tail region. The islets in Indian population were relatively smaller in size, but they have more beta cells (20%) when compared to American population. Interpretation & conclusions: The beta cells of larger islets are functionally more active than the smaller islets via paracrine effect. Thus, reduction in the number of larger islets may be one of the probable reasons for increased susceptibility of Indians to diabetes even at lower BMI. Knowledge about the regional distribution of islets will help the surgeons to preserve the islet rich regions during surgery.

Assessing the impact of cigarette smoking on β-cell function and risk for type 2 diabetes in a non-diabetic Chinese cohort

Although the impact of cigarette smoking on glucose homeostasis has been extensively studied, the results, however, are still not conclusive. We, therefore, conducted a cross-sectional analysis of a non-diabetic Chinese cohort collected by the China Health and Nutrition Survey (CHNS 2009) to comprehensively assess the relationship between smoking, Hemoglobin A1c, β-cell function and insulin sensitivity. The cohort included a total of 5965 individuals (47.4% male) with a mean age of 49.23 years, and 4140 of which were non-smokers (69.4%), 834 were current light smokers (13.9%) and 991 were current heavy smokers (16.6%). Current smokers were predominantly males (93.6%) with a lower BMI (22.95 versus 23.42 kg/m²). HbA1c levels were dose-dependently increased with smoking exposure (5.39%, 5.42% and 5.45%, respectively, P = 0.007). Non-smokers were served as a referent, the adjusted ORs for type 2 diabetes were 1.12 (P = 0.256, light smokers) and 1.26 (P = 0.014, heavy smokers), indicating a positive relationship between cigarette smoking and incidence of diabetes. HOMA%B was decreased in a dose-responsive manner with cigarette smoking (4.80, 4.79 and 4.76, P = 0.036), suggesting an adverse effect of smoking on β-cell function. Collectively, cigarette smoking is dose-dependently associated with decreased HOMA%B, and current smokers were clearly in a higher risk for diabetes as manifested by the elevated HbA1c.

The Emerging Role of Biomarkers in the Diagnosis of Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM) is a common complication of pregnancy; its rising incidence is a result of increased maternal obesity and older maternal age together with altered diagnostic criteria identifying a greater proportion of pregnant women with GDM. Its consequences are far-reaching, associated with poorer maternal and neonatal outcomes compared to non-GDM pregnancies, and GDM has implications for metabolic health in both mother and offspring. Objective markers to identify women at high risk for the development of GDM are useful to target therapy and potentially prevent its development. Established clinical risk factors for GDM include overweight/obesity, age, ethnicity, and family history of diabetes, though they lack specificity for its development. The addition of biomarkers to predictive models of GDM may improve the ability to identify women at risk of GDM prior to its development. These biomarkers reflect the pathophysiologic mechanisms of GDM involving insulin resistance, chronic inflammation, and altered placental function. In addition, the role of epigenetic changes in GDM pathogenesis highlights the complex interplay between genetic and environmental factors, potentially offering further refinement of the prediction of GDM risk. In this review, we will discuss the clinical challenges associated with the diagnosis of GDM and its current pathophysiologic basis, giving rise to potential biomarkers that may aid in its identification. While not yet validated for clinical use, we explore the possible clinical role of biomarkers in the future. We also explore novel diagnostic tools, including high throughput methodologies, that may have potential future application in the identification of women with GDM.