Central Nervous System Control of Glucose Homeostasis: A Therapeutic Target for Type 2 Diabetes?

Historically, pancreatic islet beta cells have been viewed as principal regulators of glycemia, with type 2 diabetes (T2D) resulting when insulin secretion fails to compensate for peripheral tissue insulin resistance. However, glycemia is also regulated by insulin-independent mechanisms that are dysregulated in T2D. Based on evidence supporting its role both in adaptive coupling of insulin secretion to changes in insulin sensitivity and in the regulation of insulin-independent glucose disposal, the central nervous system (CNS) has emerged as a fundamental player in glucose homeostasis. Here, we review and expand upon an integrative model wherein the CNS, together with the islet, establishes and maintains the defended level of glycemia. We discuss the implications of this model for understanding both normal glucose homeostasis and T2D pathogenesis and highlight centrally targeted therapeutic approaches with the potential to restore normoglycemia to patients with T2D.

A Randomized Controlled Clinical Trial of Lifestyle Intervention and Pioglitazone for Normalization of Glucose Status in Chinese with Prediabetes

Aims. Prediabetes has been proved as an important risk factor of both diabetes and cardiovascular disease (CVD). Previous studies have shown that both lifestyle intervention and pioglitazone may delay the development of diabetes in patients with prediabetes. However, no study has ever explored whether these interventions could revert prediabetes to normal glycemic status as the primary outcome. Interventions that may revert prediabetes back to normal glucose status would be of great clinical importance. Materials and Methods. We conducted a randomized, multicenter, 2 × 2 factorial designed study to examine whether intensive lifestyle intervention and/or pioglitazone could revert prediabetes to normal glucose tolerance. The participants were followed up for three years unless they reverted to normal glucose state or developed diabetes at the annual oral glucose tolerance test (OGTT). Reversion to normal glucose tolerance was confirmed on the basis of the results of OGTT. Results. In our study, 1945 eligible patients were ultimately randomized into four groups. In this three-year follow-up study, overall, 60.0%, 50.3%, 56.6% and 65.1% reverted back to normoglycemic state over 3 years of follow-up in the conventional lifestyle intervention plus placebo, intensive lifestyle intervention plus placebo, conventional lifestyle intervention plus pioglitazone, and intensive lifestyle intervention plus pioglitazone groups, respectively. Compared to the conventional lifestyle intervention plus placebo group, all the other three groups did not show any significant benefit in terms of reverting back to normoglycemic state. Conclusion. In our study, for patients with prediabetes, neither intensive lifestyle intervention nor pioglitazone had led to a higher reversion rate to normal glucose state. Trail registration.http://www.chictr.org.cn: ChiCTR-PRC-06000005.

Association Between Serum Furin and Fasting Glucose: A Cross-Sectional Study in Chinese Adults

BackgroundFurin has been associated with glucose metabolic phenotypes in small sampled clinical studies. However, this association has not yet been studied in Chinese. Here, we aimed to examine the association between serum furin and fasting glucose in Chinese adults.MethodsSerum furin and fasting plasma glucose were assayed for 2,172 participants (mean aged 53 years, 38% men) in the Gusu cohort. A median regression model was applied to examine the association between serum furin and fasting glucose, adjusting for age, sex, education level, cigarette smoking, alcohol drinking, obesity, blood pressure, and lipids. To facilitate data interpretation, the association between serum furin and prevalent diabetes was also examined.ResultsSerum furin was negatively associated with fasting glucose (β=-0.18, P<0.001 for log-furin). In participants with diabetes, serum furin was significantly lower than those with normal glucose (median: 0.90 ng/mL vs. 1.05 ng/mL, P=0.001). Compared with participants in the highest quartile of serum furin, those in the lowest quartile had 42% and 80% increased risk of prevalent prediabetes (OR=1.42, 95%CI: 1.05-1.92, P=0.023) and diabetes (OR=1.80, 95%CI: 1.13-2.91, P=0.015), respectively.ConclusionsSerum furin was negatively associated with prediabetes and diabetes in Chinese adults. Our findings suggest that serum furin may be a risk factor or a biomarker of diabetes.

Relative Frequency of Islet Autoimmunity in Children and Adolescents with Autoimmune Thyroid Disease

The present study aims to investigate islet autoimmunity and susceptibility to type 1 diabetes (T1D) in children/adolescents with autoimmune thyroid disease (AITD), and family members of AITD patients with islet autoimmunity. Islet-cell cytoplasmic, glutamic-acid decarboxylase and tyrosine-phosphatase autoantibodies were measured in 161 AITD patients [(127 with autoimmune thyroiditis (AT); 34 with Graves’ disease (GD)], 20 family members of AITD patients with islet autoimmunity, and 155 age-matched controls. Islet autoimmunity was found in 10.6% of AITD patients, significantly more frequent than in controls (1.9%; p=0.002). Higher prevalence of islet autoantibodies was found in females with AITD (p=0.011) but not in males (p=0.16) as well as in AT (p=0.013) but not GD patients (p=0.19), compared to corresponding controls. Two or three islet autoantibodies were found concurrently in six AITD patients with islet autoimmunity. They all developed T1D and had significantly higher islet autoantibodies titers (p=0.01) compared to AITD patients with single islet autoantibodies but normal glucose metabolism. T1D was found in 3.7% of AITD patients compared to 0.2% in age-matched, general Croatian population. Islet autoantibodies were found in 5/20 family members of AITD patients with islet autoimmunity, among which two developed T1D. None of the controls was positive to more than one islet autoantibodies or developed T1D. Conclusion: Children/adolescents with AITD (particularly females and patients with AT) represent a risk group for islet autoimmunity and T1D, as well as family members of AITD patients with positive islet autoantibodies, but last observation must be examined in a larger number of patients.

Vitamin D Status in Prediabetes and its Different Categories

Objectives: Data regarding vitamin D level and status among categories of prediabetes are scarce in the literature. This study is aimed to determine the level and status of vitamin D among adults with prediabetes and its different categories. Materials and methods: This crosssectional study was carried out in 111 newly detected adults with prediabetes according to American Diabetes Association 2018 criteria and 74 matched healthy control (normal glucose tolerance). People with prediabetes were categorized into impaired glucose tolerance, impaired fasting glucose and their combination group. Participants were recruited consecutively from the Department of Endocrinology, BSMMU to measure serum 25 hydroxyvitamin D by high performance liquid chromatography and serum intact parathormone, calcium, albumin and phosphate by chemiluminescent enzyme-labeled immunometric assay. Results: Vitamin D level and status were not significantly different between people with prediabetes & control and also in different categories of prediabetes. Severe vitamin D deficiency was significantly higher in people with prediabetes (27.5% vs 10%, p= 0.05). There were no associations between different blood glucose levels with vitamin D among adults with prediabetes. Conclusions:Vitamin D was not associated with prediabetes or its categories. Bangladesh Journal of Medical Science Vol. 21(1) 2022 Page : 120-128

Do Pregnancy Outcomes of Women With False-Positive Early Gestational Diabetes Mellitus Differ From Those of Women With Normal Glucose Tolerance?

Background: To investigate whether false-positive early gestational diabetes mellitus (GDM) women can be managed similarly as normal glucose tolerance (NGT) women.Methods: This retrospective study was conducted at a tertiary care center in Japan. Pregnancy and neonate outcomes of 117 singleton pregnancies with false-positive early GDM and 1774 singleton pregnancies with NGT who delivered after 22 weeks of gestation were compared. GDM was diagnosed according to the IADPSG criteria (patients having one or more of the following: fasting plasma glucose ≥ 92 mg/dL and a 75 g oral glucose tolerance test (OGTT) value ≥180 mg/dL at 1 h, or ≥153 mg/dL at 2 h). Pregnant women diagnosed with GDM in early pregnancy who did not meet the diagnostic criteria on the second OGTT were defined as having false-positive early GDM. Women with false-positive early GDM did not receive any therapeutic intervention during gestation.Results: Maternal age, pre-pregnancy BMI, and gestational weight gain were significantly higher in the false-positive GDM group than the NGT group. No significant differences were found in pregnancy outcomes, including gestational age, birth weight, large for gestational age rate, and cesarean delivery rate. Except for neonatal hypoglycemia rate, no significant differences were found in neonatal outcomes.Conclusions: There were no clinically significant differences between early GDM false-positive women exhibiting GDM patterns only during early pregnancy and NGT women. False-positive early GDM women can be managed similarly as NGT women, suggesting that WHO diagnostic guidelines, applying the IADPSG criteria during early pregnancy, need revision.

The GLP-1R Agonist Exendin-4 Attenuates Hyperglycemia-Induced Chemoresistance in Human Endometrial Cancer Cells Through ROS-Mediated Mitochondrial Pathway

This study aimed to assess the effects of the antidiabetic drug Exendin-4 (Exe-4), a GLP-1 receptor agonist, on the response of human endometrial cancer cells to chemotherapy under high glucose (HG) conditions. Cell viability was detected using a cell counting kit (CCK)-8. Cell apoptosis and reactive oxygen species (ROS) levels were measured by flow cytometry. Gene expression was evaluated by real-time PCR and immunoblotting. The chemotherapeutic drug cisplatin (DDP) dose-dependently inhibited both human endometrial adenocarcinoma Ishikawa and HEC1B cells, a response reversed by HG. Meanwhile, Exe-4 attenuated hyperglycemia’s effect by elevating intracellular lactate dehydrogenase (LDH) and ROS production. Similarly, DDP-induced elevation of intracellular rhodamine123 was attenuated by HG, and Exe-4 reversed HG’s impact. The chemoresistance genes multidrug resistance-associated protein 1 (MRP1) and P-glycoprotein (Pgp) were upregulated. At the same time, topoisomerase II (TOPO II) was downregulated under HG conditions, suggesting HG-induced chemoresistance. Exe-4 did not significantly influence the above genes. DDP downregulated Bcl-2 and Bcl-XL and upregulated Bax, cytosolic cytochrome c, and PARP under normal glucose (NG) versus HG conditions, and Exe-4 attenuated these effects. Upstream of Bax/Bcl, acetylated P53 was upregulated by DDP and downregulated by HG, whose effect was reversed by Exe-4. DPP treatment significantly induced apoptosis and cell cycle arrest in the S phase under NG, and HG reduced these effects. Prolonged exposure to HG induces DDP chemoresistance in human endometrial cancer cells but is alleviated by Exe-4.

Liraglutide Inhibits Osteoclastogenesis and Improves Bone Loss by Downregulating Trem2 in Female Type 1 Diabetic Mice: Findings From Transcriptomics

BackgroundThe mechanisms of bone fragility in type 1 diabetes (T1D) are not fully understood. Whether glucagon-like peptide-1 receptor (GLP-1R) agonists could improve bone quality in T1D context also remains elusive.AimsWe aimed to explore the possible mechanisms of bone loss in T1D and clarify whether liraglutide has effects on bone quality of T1D mice using transcriptomics.MethodsFemale streptozotocin-induced diabetic C57BL/6J mice were randomly divided into four groups and received the following treatments daily for 8 weeks: saline as controls, insulin, liraglutide, and liraglutide combined with insulin. These groups were also compared with non-STZ-treated normal glucose tolerance (NGT) group. Trunk blood and bone tissues were collected for analysis. Three tibia from each of the NGT, saline-treated, and liraglutide-treated groups were randomly selected for transcriptomics.ResultsCompared with NGT mice, saline-treated T1D mice manifested markedly hyperglycemia and weight loss, and micro-CT revealed significantly lower bone mineral density (BMD) and deficient microarchitectures in tibias. Eight weeks of treatment with liraglutide alone or combined with insulin rescued the decreased BMD and partly corrected the compromised trabecular microarchitectures. Transcriptomics analysis showed there were 789 differentially expressed genes mainly mapped to osteoclastogenesis and inflammation pathways. The RT-qPCR verified that the gene expression of Trem2, Nfatc1, Trap, and Ctsk were significantly increased in the tibia of T1D compared with those in the NGT group. Liraglutide treatment alone or combined with insulin could effectively suppress osteoclastogenesis by downregulating the gene expression of Trem2, Nfatc1, Ctsk, and Trap.ConclusionsTaken together, increased osteoclastogenesis with upregulated expression of Trem2 played an important role in bone loss of T1D mice. Liraglutide provided protective effects on bone loss in T1D mice by suppressing osteoclastogenesis.