Development of Type 1 Diabetes may occur through a Type 2 Diabetes mechanism

Association of obesity- and insulin resistance-related indices with subclinical carotid atherosclerosis in type 1 diabetes: a cross-sectional study

BACKGROUND

Obesity and insulin resistance are well-established risk factors for atherosclerosis and cardiovascular disease (CVD). Although some obesity- and insulin resistance-related indices (OIRIs) have been linked to CVD, their associations with subclinical carotid atherosclerosis (SCA) in individuals with type 1 diabetes (T1D) remain unclear. This study aims to systematically explore and compare the associations of various common OIRIs with SCA in T1D population.

METHODS

A total of 418 adult inpatients with classic T1D admitted from October 2008 to June 2021 to the First Affiliated Hospital of Air Force Medical University in Xi'an, China were included in this study. Demographic, anthropometric, and laboratory data were collected. Studied OIRIs comprised body mass index, waist-to-height ratio, waist-to-hip ratio (WHR), a body shape index, abdominal volume index, body adiposity index, body roundness index, conicity index, triglyceride-glucose index, visceral adiposity index, Chinese visceral adiposity index (CVAI), lipid accumulation product, estimated glucose disposal rate (eGDR), triglyceride-to-HDL ratio, and cardiometabolic index. Binary logistic regression, restricted cubic spline (RCS), and receiver operating characteristic curves were used to examine the associations of these indices with SCA.

RESULTS

In multivariable logistic regression analyses, after adjusting for potential confounders, per 1.0-standard deviation (SD) increase in CVAI (OR, 95% CI: 1.68, 1.16-2.47), eGDRWHR (eGDR calculated with WHR; OR, 95% CI: 0.44, 0.22-0.82), and eGDRWC (eGDR calculated with waist circumference; OR, 95% CI: 0.49, 0.24-0.93) were significantly associated with SCA. CVAI exhibited the highest area under the curve (AUC) in diagnosing SCA, with a value of 0.73 (95% CI: 0.69-0.77). RCS analyses indicated a linear and positive association between CVAI and SCA in the overall population and the females. Subgroup analyses and sensitivity analyses further supported the association between CVAI and SCA. Additionally, adding CVAI to the Steno Type 1 Risk Engine (ST1RE) improved the reclassification, but did not enhance the overall discriminative ability of ST1RE to identify SCA.

CONCLUSION

Among various OIRIs, CVAI shows the strongest association with SCA in adults with T1D. These findings suggest that CVAI may merit further longitudinal investigation as a potential marker for SCA assessment in this population.

Glucagon-like peptide-1 agonists: Role of the gut in hypoglycemia unawareness, and the rationale in type 1 diabetes

Type 1 diabetes is increasing and the majority of patients have poor glycemic control. Although advanced technology and nanoparticle use have greatly enhanced insulin delivery and glucose monitoring, weight gain and hypoglycemia remain major challenges and a constant source of concern for patients with type 1 diabetes. Type 1 diabetes shares some pathophysiology with type 2 diabetes, and an overlap has been reported. The above observation created great interest in glucagon-like peptide-1 receptor agonists (GLP-1) as adjuvants for type 1 diabetes. Previous trials confirmed the positive influence of GLP-1 agonists on β cell function. However, hypoglycemia unawareness and dysregulated glucagon response have been previously reported in patients with recurrent hypoglycemia using GLP-1 agonists. Jin et al found that the source of glucagon dysregulation due to GLP-1 agonists resides in the gut. Plausible explanations could be gut nervous system dysregulation or gut microbiota disruption. This review evaluates the potential of GLP-1 agonists in managing type 1 diabetes, particularly focusing on their impact on glycemic control, weight management, and glucagon dysregulation. We provide a broader insight into the problem of type 1 diabetes mellitus management in the light of recent findings and provide future research directions.

Influence of sphingolipid enzymes on blood glucose levels, development of diabetes, and involvement of pericytes

AIMS

Sulfatide is a chaperone for insulin manufacturing in beta cells. Here we explore whether the blood glucose values normally could be associated with this sphingolipid and especially two of its building enzymes CERS2 and CERS6. Both T1D and T2D have low blood sulfatide levels, and insulin resistance on beta cells at clinical diagnosis. Furthermore, we examined islet pericytes for sulfatide, and beta-cell receptors for GLP-1, both of which are related to the insulin production.

MATERIALS AND METHODS

We examined mRNA levels in islets from the DiViD and nPOD studies, performed genetic association analyses, and histologically investigated pericytes in the islets for sulfatide.

RESULTS

Polymorphisms of the gene encoding the CERS6 enzyme responsible for synthesising dihydroceramide, a precursor to sulfatide, are associated with random blood glucose values in non-diabetic persons. This fits well with our finding of sulfatide in pericytes in the islets, which regulates the capillary blood flow in the islets of Langerhans, which is important for oxygen supply to insulin production. In the islets of newly diagnosed T1D patients, we observed low levels of GLP-1 receptors; this may explain the insulin resistance in their beta cells and their low insulin production. In T2D patients, we identified associated polymorphisms in both CERS2 and CERS6.

CONCLUSIONS

Here, we describe several polymorphisms in sulfatide enzymes related to blood glucose levels and HbA1c in non-diabetic individuals. Islet pericytes from such persons contain sulfatide. Furthermore, low insulin secretion in newly diagnosed T1D may be explained by beta-cell insulin resistance due to low levels of GLP-1 receptors.

Insulitis in human type 1 diabetes: lessons from an enigmatic lesion

Type 1 diabetes is caused by a deficiency of insulin secretion which has been considered traditionally as the outcome of a precipitous decline in the viability of β-cells in the islets of Langerhans, brought about by autoimmune-mediated attack. Consistent with this, various classes of lymphocyte, as well as cells of the innate immune system have been found in association with islets during disease progression. However, analysis of human pancreas from subjects with type 1 diabetes has revealed that insulitis is often less intense than in equivalent animal models of the disease and can affect many fewer islets than expected, at disease onset. This is especially true in subjects developing type 1 diabetes in, or beyond, their teenage years. Such studies imply that both the phenotype and the number of immune cells present within insulitic lesions can vary among individuals in an age-dependent manner. Additionally, the influent lymphocytes are often mainly arrayed peripherally around islets rather than gaining direct access to the endocrine cell core. Thus, insulitis remains an enigmatic phenomenon in human pancreas and this review seeks to explore the current understanding of its likely role in the progression of type 1 diabetes.

The pathogenic "symphony" in type 1 diabetes: A disorder of the immune system, β cells, and exocrine pancreas

Type 1 diabetes (T1D) is widely considered to result from the autoimmune destruction of insulin-producing β cells. This concept has been a central tenet for decades of attempts seeking to decipher the disorder's pathogenesis and prevent/reverse the disease. Recently, this and many other disease-related notions have come under increasing question, particularly given knowledge gained from analyses of human T1D pancreas. Perhaps most crucial are findings suggesting that a collective of cellular constituents-immune, endocrine, and exocrine in origin-mechanistically coalesce to facilitate T1D. This review considers these emerging concepts, from basic science to clinical research, and identifies several key remaining knowledge voids.

Can type 1 diabetes be an unexpected complication of obesity?

Type 1 diabetes (T1D) is one of the most common chronic autoimmune diseases, characterized by absolute insulin deficiency caused via inflammatory destruction of the pancreatic β-cell. Genetic, epigenetic, and environmental factors play a role in the development of diseases. Almost ⅕ of cases involve people under the age of 20. In recent years, the incidence of both T1D and obesity has been increasing, especially among children, adolescents, and young people. In addition, according to the latest study, the prevalence of overweight or obesity in people with T1D has increased significantly. The risk factors of weight gain included using exogenous insulin, intensifying insulin therapy, fear of hypoglycemia and related decrease in physical activity, and psychological factors, such as emotional eating and binge eating. It has also been suggested that T1D may be a complication of obesity. The relationship between body size in childhood, increase in body mass index values in late adolescence and the development of T1D in young adulthood is considered. Moreover, the coexistence of T1D and T2D is increasingly observed, this situation is called double or hybrid diabetes. This is associated with an increased risk of the earlier development of dyslipidemia, cardiovascular diseases, cancer, and consequently a shortening of life. Thus, the purpose of this review was to summarize the relationships between overweight or obesity and T1D.