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Annals of Internal Medicine Sep 2023
Topics: Humans; Prescription Drugs; Insulin; Insulins
PubMed: 37665994
DOI: 10.7326/M23-1105 -
The Journal of Endocrinology Aug 2023Glucagon is a peptide hormone that is produced primarily by the alpha cells in the islet of Langerhans in the pancreas, but also in intestinal enteroendocrine cells and...
Glucagon is a peptide hormone that is produced primarily by the alpha cells in the islet of Langerhans in the pancreas, but also in intestinal enteroendocrine cells and in some neurons. Approximately 100 years ago, several research groups discovered that pancreatic extracts would cause a brief rise in blood glucose before they observed the decrease in glucose attributed to insulin. An overall description of the regulation of glucagon secretion requires the inclusion of its sibling insulin because they both are made primarily by the islet and they both regulate each other in different ways. For example, glucagon stimulates insulin secretion, whereas insulin suppresses glucagon secretion. The mechanism of action of glucagon on insulin secretion has been identified as a trimeric guanine nucleotide-binding protein (G-protein)-mediated event. The manner in which insulin suppresses glucagon release from the alpha cell is thought to be highly dependent on the peri-portal circulation of the islet through which blood flows downstream from beta cells to alpha cells. In this scenario, it is via the circulation that insulin is thought to suppress the release of glucagon. However, high levels of glucose also have been shown to suppress glucagon secretion. Consequently, the glucose-lowering effect of insulin may be additive to the direct effects of insulin to suppress alpha cell function, so that in vivo both the discontinuation of the insulin signal and the condition of low glucose jointly are responsible for induction of glucagon secretion.
Topics: Glucagon; Islets of Langerhans; Glucagon-Like Peptide 1; Insulin; Glucagon-Secreting Cells; Glucose
PubMed: 37227172
DOI: 10.1530/JOE-22-0224 -
Problemy Endokrinologii Feb 2024Insulinoma is the most common hormonally active neuroendocrine tumor (NET) of the pancreas. In recent years, there has been a trend towards an increase in the incidence... (Review)
Review
RELEVANCE
Insulinoma is the most common hormonally active neuroendocrine tumor (NET) of the pancreas. In recent years, there has been a trend towards an increase in the incidence of NET especially insulinoma.
AIM
Summarizing and analyzing current data on various approaches to the treatment of insulinoma. Our review includes a comprehensive assessment of the advantages and disadvantages of currently available insulinoma treatment methods in comparison with past experience, as well as a review of promising methods that are not currently widely used.
MATERIALS AND METHODS
Analysis of literature from such databases as scientific electronic library elibrary.ru, Pubmed, Google Scholar, MedLine, Scopus and Web of Science.
RESULTS
The most common treatment for insulinoma is surgery. For patients with high operative risk, alternative methods such as alcohol ablation, radiofrequency ablation, and tumor embolization may be used. Medications include the use of somatostatin analogues, diazoxide. The literature describes the potential benefit of the use of beta-blockers, phenytoin, glucagon, however, in clinical trials, these drugs have not demonstrated a significant effect. For the treatment of malignant and metastatically advanced insulinoma, targeted therapy (primarily Everolimus), chemotherapy, as well as embolization (including chemoembolization, radioembolization), radiofrequency ablation (RFA), microwave ablation and cryoablation, ultrasound ablation (HIFU), laser ablation, brachytherapy, irreversible electroporation are used.
CONCLUSION
The study of new drugs is an important task for scientists, among medications the most promising are new generations of somatostatin analogues, targeted drugs and chemotherapy drugs. The rare frequency of insulinoma makes it difficult to conduct randomized controlled trials and prospective studies. That is why physicians and scientists need to maintain close contacts with each other and take into account the experience of treating each patient with such disease, which will help develop effective treatment algorithms in the future.
Topics: Humans; Insulinoma; Prospective Studies; Neuroendocrine Tumors; Apudoma; Pancreatic Neoplasms; Somatostatin
PubMed: 38433541
DOI: 10.14341/probl13281 -
JCI Insight Aug 2023Type 2 diabetes (T2D) is associated with compromised identity of insulin-producing pancreatic islet β cells, characterized by inappropriate production of other islet...
Type 2 diabetes (T2D) is associated with compromised identity of insulin-producing pancreatic islet β cells, characterized by inappropriate production of other islet cell-enriched hormones. Here, we examined how hormone misexpression was influenced by the MAFA and MAFB transcription factors, closely related proteins that maintain islet cell function. Mice specifically lacking MafA in β cells demonstrated broad, population-wide changes in hormone gene expression with an overall gene signature closely resembling islet gastrin+ (Gast+) cells generated under conditions of chronic hyperglycemia and obesity. A human β cell line deficient in MAFB, but not one lacking MAFA, also produced a GAST+ gene expression pattern. In addition, GAST was detected in human T2D β cells with low levels of MAFB. Moreover, evidence is provided that human MAFB can directly repress GAST gene transcription. These results support a potentially novel, species-specific role for MafA and MAFB in maintaining adult mouse and human β cell identity, respectively. Here, we discuss the possibility that induction of Gast/GAST and other non-β cell hormones, by reduction in the levels of these transcription factors, represents a dysfunctional β cell signature.
Topics: Adult; Humans; Animals; Mice; MafB Transcription Factor; Diabetes Mellitus, Type 2; Islets of Langerhans; Insulin-Secreting Cells; Insulin
PubMed: 37606041
DOI: 10.1172/jci.insight.166386 -
ELife Sep 2023Pancreatic α-cells secrete glucagon, an insulin counter-regulatory peptide hormone critical for the maintenance of glucose homeostasis. Investigation of the function of...
Pancreatic α-cells secrete glucagon, an insulin counter-regulatory peptide hormone critical for the maintenance of glucose homeostasis. Investigation of the function of human α-cells remains a challenge due to the lack of cost-effective purification methods to isolate high-quality α-cells from islets. Here, we use the reaction-based probe diacetylated Zinpyr1 (DA-ZP1) to introduce a novel and simple method for enriching live α-cells from dissociated human islet cells with ~95% purity. The α-cells, confirmed by sorting and immunostaining for glucagon, were cultured up to 10 days to form α-pseudoislets. The α-pseudoislets could be maintained in culture without significant loss of viability, and responded to glucose challenge by secreting appropriate levels of glucagon. RNA-sequencing analyses (RNA-seq) revealed that expression levels of key α-cell identity genes were sustained in culture while some of the genes such as , , were altered in α-pseudoislets in a time-dependent manner. In conclusion, we report a method to sort human primary α-cells with high purity that can be used for downstream analyses such as functional and transcriptional studies.
Topics: Humans; Glucagon; Transcriptome; Islets of Langerhans; Insulin; Glucagon-Secreting Cells; Glucose; Fluoresceins; Insulin-Secreting Cells
PubMed: 37732504
DOI: 10.7554/eLife.85056 -
Canadian Journal of Diabetes Dec 2023
Topics: Humans; Insulin
PubMed: 37211042
DOI: 10.1016/j.jcjd.2023.05.007 -
Diabetologia Jul 2024Protein kinase CK2 acts as a negative regulator of insulin expression in pancreatic beta cells. This action is mainly mediated by phosphorylation of the transcription...
AIMS/HYPOTHESIS
Protein kinase CK2 acts as a negative regulator of insulin expression in pancreatic beta cells. This action is mainly mediated by phosphorylation of the transcription factor pancreatic and duodenal homeobox protein 1 (PDX1). In pancreatic alpha cells, PDX1 acts in a reciprocal fashion on glucagon (GCG) expression. Therefore, we hypothesised that CK2 might positively regulate GCG expression in pancreatic alpha cells.
METHODS
We suppressed CK2 kinase activity in αTC1 cells by two pharmacological inhibitors and by the CRISPR/Cas9 technique. Subsequently, we analysed GCG expression and secretion by real-time quantitative RT-PCR, western blot, luciferase assay, ELISA and DNA pull-down assays. We additionally studied paracrine effects on GCG secretion in pseudoislets, isolated murine islets and human islets. In vivo, we examined the effect of CK2 inhibition on blood glucose levels by systemic and alpha cell-specific CK2 inhibition.
RESULTS
We found that CK2 downregulation reduces GCG secretion in the murine alpha cell line αTC1 (e.g. from 1094±124 ng/l to 459±110 ng/l) by the use of the CK2-inhibitor SGC-CK2-1. This was due to a marked decrease in Gcg gene expression through alteration of the binding of paired box protein 6 (PAX6) and transcription factor MafB to the Gcg promoter. The analysis of the underlying mechanisms revealed that both transcription factors are displaced by PDX1. Ex vivo experiments in isolated murine islets and pseudoislets further demonstrated that CK2-mediated reduction in GCG secretion was only slightly affected by the higher insulin secretion after CK2 inhibition. The kidney capsule transplantation model showed the significance of CK2 for GCG expression and secretion in vivo. Finally, CK2 downregulation also reduced the GCG secretion in islets isolated from humans.
CONCLUSIONS/INTERPRETATION
These novel findings not only indicate an important function of protein kinase CK2 for proper GCG expression but also demonstrate that CK2 may be a promising target for the development of novel glucose-lowering drugs.
Topics: Casein Kinase II; Animals; Glucagon; Mice; Humans; Glucagon-Secreting Cells; Homeodomain Proteins; Trans-Activators; Male; Cell Line; Insulin
PubMed: 38503901
DOI: 10.1007/s00125-024-06128-1 -
International Journal of Molecular... Aug 2023Research in the treatment of type 1 diabetes has been addressed into two main areas: the development of "intelligent insulins" capable of auto-regulating their own... (Review)
Review
Research in the treatment of type 1 diabetes has been addressed into two main areas: the development of "intelligent insulins" capable of auto-regulating their own levels according to glucose concentrations, or the exploitation of artificial intelligence (AI) and its learning capacity, to provide decision support systems to improve automated insulin therapy. This review aims to provide a synthetic overview of the current state of these two research areas, providing an outline of the latest development in the search for "intelligent insulins," and the results of new and promising advances in the use of artificial intelligence to regulate automated insulin infusion and glucose control. The future of insulin treatment in type 1 diabetes appears promising with AI, with research nearly reaching the possibility of finally having a "closed-loop" artificial pancreas.
Topics: Humans; Insulin; Diabetes Mellitus, Type 1; Artificial Intelligence; Insulin, Regular, Human; Intelligence
PubMed: 37685946
DOI: 10.3390/ijms241713139 -
Communications Biology Aug 2023Although insulin mediated glucose uptake in skeletal muscle is a major mechanism ensuring glucose disposal in humans, glucose effectiveness, i.e., the ability of glucose...
Although insulin mediated glucose uptake in skeletal muscle is a major mechanism ensuring glucose disposal in humans, glucose effectiveness, i.e., the ability of glucose itself to stimulate its own uptake independent of insulin, accounts for roughly half of the glucose disposed during an oral glucose tolerance test. Both insulin dependent and insulin independent skeletal muscle glucose uptake are however reduced in individuals with diabetes. We here show that AMPK activator O304 stimulates insulin independent glucose uptake and utilization in skeletal muscle and heart in vivo, while preventing glycogen accumulation. Combined glucose uptake and utilization requires an increased metabolic demand and we show that O304 acts as a mitochondrial uncoupler, i.e., generates a metabolic demand. O304 averts gene expression changes associated with metabolic inflexibility in skeletal muscle and heart of diabetic mice and reverts diabetic cardiomyopathy. In Type 2 diabetes, insulin resistance elicits compensatory insulin hypersecretion, provoking β-cell stress and eventually compensatory failure. In db/db mice O304 preserves β-cell function by preventing decline in insulin secretion, β-cell mass, and pancreatic insulin content. Thus, as a dual AMPK activator and mitochondrial uncoupler O304 mitigates two central defects of T2D; impaired glucose uptake/utilization and β-cell failure, which today lack effective treatment.
Topics: Humans; Mice; Animals; Glucose; Diabetes Mellitus, Type 2; Diabetes Mellitus, Experimental; Hyperglycemia; Insulin, Regular, Human; Muscle, Skeletal; Insulin
PubMed: 37626210
DOI: 10.1038/s42003-023-05255-6 -
The New England Journal of Medicine Jul 2023
Topics: Humans; Hypoglycemic Agents; Insulin; Drug Design
PubMed: 37494489
DOI: 10.1056/NEJMe2307280