Vasoactive intestinal peptide (VIP), a small neuropeptide composing of 28 amino acids, functions as a neuromodulator with insulinotropic effect on pancreatic β cells, in which it is of vital importance in regulating the levels of blood glucose. VIP potently agonizes VPAC2 receptor (VPAC2-R). Agonists of VPAC2-R stimulate glucose-dependent insulin secretion. The purpose of this study was to further investigate the possible ion channel mechanisms in VPAC2-R-mediated VIP-potentiated insulin secretion. The results of insulin secretion experiments showed that VIP augmented insulin secretion in a glucose-dependent manner. The insulinotropic effect was mediated by VPAC2-R rather than VPAC1 receptor (VPAC1-R), through the adenylyl cyclase (AC)/protein kinase A (PKA) signalling pathway. The calcium imaging analysis demonstrated that VIP increased intracellular Ca concentration ([Ca]). In addition, in the whole-cell voltage-clamp mode, we found that VIP blocked the voltage-dependent potassium (Kv) channel currents, while this effect was reversed by inhibiting the VPAC2-R, AC or PKA respectively. Taken together, these findings suggest that VIP stimulates insulin secretion by inhibiting the Kv channels, activating the Ca channels, and increasing [Ca] through the VPAC2-R and AC/PKA signalling pathway. These findings provide theoretical basis for the research of VPAC2-R as a novel therapeutic target.
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http://dx.doi.org/10.1016/j.yexcr.2023.113471 | DOI Listing |
Diabetes Metab Syndr Obes
January 2025
Department of Diabetes, Metabolism and Endocrinology, Toho University Graduate School of Medicine, Tokyo, Japan.
Purpose: Imeglimin is a novel oral antidiabetic agent that improves glucose tolerance. This study aimed to investigate the efficacy of combining imeglimin with dipeptidyl peptidase-4 inhibitor (DPP-4i), the most frequently prescribed first-line treatment for patients with type 2 diabetes (T2D) in Japan, to improve glycemic control.
Patients And Methods: Eleven patients with T2D treated with DPP-4i alone (6.
Diabetes Obes Metab
January 2025
Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
Aims: To compare the probability of achieving diabetes remission in individuals with different phenotypes of insulin sensitivity, insulin secretion, and beta cell function and further detect the effects of diet, exercise, and lifestyle education intervention on these indexes.
Methods: Three-hundred and one participants who had glycated haemoglobin (HbA1c) data at baseline and after intervention were included for this post hoc analysis. We used the multi-way analysis of variance to assess the differences between the diabetes remission and non-remission groups or between intervention groups in changes of the indexes of insulin sensitivity, insulin secretion, and beta cell function.
Diabetes Obes Metab
January 2025
National Engineering Research Center for Biomaterials, College of Biomedical Engineering, Sichuan University, Chengdu, Sichuan, People's Republic of China.
Aim: To achieve glucose-activated transcriptional regulation of insulin analogue in skeletal muscle of T1D mice, thereby controlling blood glucose levels and preventing or mitigating diabetes-related complications.
Materials And Methods: We developed the GANIT (Glucose-Activated NFAT-regulated INSA-F Transcription) system, an innovative platform building upon the previously established intramuscular plasmid DNA (pDNA) delivery and expression system. In the GANIT system, skeletal muscle cells are genetically engineered to endogenously produce the insulin analogue INSA-F (Insulin Aspart with Furin cleavage sites).
J Atheroscler Thromb
January 2025
Department of Endocrinology and Metabolism, Institute of Medicine, University of Tsukuba.
Diabetes mellitus, particularly type 2 diabetes mellitus (T2DM), is a pervasive chronic disease that affects millions of people worldwide. It predisposes individuals to a range of severe microvascular and macrovascular complications, which drastically impact the patient's quality of life and increase mortality rates owing to various comorbidities. This extensive review explores the intricate pathophysiology underlying diabetic complications, focusing on key mechanisms, such as atherosclerosis, insulin resistance, chronic inflammation, and endothelial dysfunction.
View Article and Find Full Text PDFDiabetes Care
January 2025
Division of Pediatric and Adolescent Medicine, Oslo University Hospital, Oslo, Norway.
Objective: In the Diabetes Virus Detection and Intervention trial, antiviral treatment with pleconaril and ribavirin decreased the decline, compared with placebo, in endogenous C-peptide 1 year after diagnosis of type 1 diabetes (T1D) in children and adolescents. This article reports the results 2 and 3 years after diagnosis.
Research Design And Methods: This was a multicenter, randomized, placebo-controlled (1:1) trial of 96 children and adolescents aged 6-15.
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