Interorgan crosstalk in pancreatic islet function and pathology

A nutrient responsive lipase mediates gut-brain communication to regulate insulin secretion in Drosophila

Pancreatic β cells secrete insulin in response to glucose elevation to maintain glucose homeostasis. A complex network of inter-organ communication operates to modulate insulin secretion and regulate glucose levels after a meal. Lipids obtained from diet or generated intracellularly are known to amplify glucose-stimulated insulin secretion, however, the underlying mechanisms are not completely understood. Here, we show that a Drosophila secretory lipase, Vaha (CG8093), is synthesized in the midgut and moves to the brain where it concentrates in the insulin-producing cells in a process requiring Lipid Transfer Particle, a lipoprotein originating in the fat body. In response to dietary fat, Vaha stimulates insulin-like peptide release (ILP), and Vaha deficiency results in reduced circulatory ILP and diabetic features including hyperglycemia and hyperlipidemia. Our findings suggest Vaha functions as a diacylglycerol lipase physiologically, by being a molecular link between dietary fat and lipid amplified insulin secretion in a gut-brain axis.

Liver resection volume-dependent pancreatic strain following living donor hepatectomy

The liver and pancreas work together to recover homeostasis after hepatectomy. This study aimed to investigate the effect of liver resection volume on the pancreas. We collected clinical data from 336 living liver donors. They were categorized into left lateral sectionectomy (LLS), left lobectomy, and right lobectomy (RL) groups. Serum pancreatic enzymes were compared among the groups. Serum amylase values peaked on postoperative day (POD) 1. Though they quickly returned to preoperative levels on POD 3, 46% of cases showed abnormal values on POD 7 in the RL group. Serum lipase levels were highest at POD 7. Lipase values increased 5.7-fold on POD 7 in the RL group and 82% of cases showed abnormal values. The RL group's lipase was twice that of the LLS group. A negative correlation existed between the remnant liver volume and amylase (r = - 0.326)/lipase (r = - 0.367) on POD 7. Furthermore, a significant correlation was observed between POD 7 serum bilirubin and amylase (r = 0.379)/lipase (r = 0.381) levels, indicating cooccurrence with liver and pancreatic strain. Pancreatic strain due to hepatectomy occurs in a resection/remnant liver volume-dependent manner. It would be beneficial to closely monitor pancreatic function in patients undergoing a major hepatectomy.

Mitochondrial bioenergetics, metabolism, and beyond in pancreatic β-cells and diabetes

In Type 1 and Type 2 diabetes, pancreatic β-cell survival and function are impaired. Additional etiologies of diabetes include dysfunction in insulin-sensing hepatic, muscle, and adipose tissues as well as immune cells. An important determinant of metabolic health across these various tissues is mitochondria function and structure. This review focuses on the role of mitochondria in diabetes pathogenesis, with a specific emphasis on pancreatic β-cells. These dynamic organelles are obligate for β-cell survival, function, replication, insulin production, and control over insulin release. Therefore, it is not surprising that mitochondria are severely defective in diabetic contexts. Mitochondrial dysfunction poses challenges to assess in cause-effect studies, prompting us to assemble and deliberate the evidence for mitochondria dysfunction as a cause or consequence of diabetes. Understanding the precise molecular mechanisms underlying mitochondrial dysfunction in diabetes and identifying therapeutic strategies to restore mitochondrial homeostasis and enhance β-cell function are active and expanding areas of research. In summary, this review examines the multidimensional role of mitochondria in diabetes, focusing on pancreatic β-cells and highlighting the significance of mitochondrial metabolism, bioenergetics, calcium, dynamics, and mitophagy in the pathophysiology of diabetes. We describe the effects of diabetes-related gluco/lipotoxic, oxidative and inflammation stress on β-cell mitochondria, as well as the role played by mitochondria on the pathologic outcomes of these stress paradigms. By examining these aspects, we provide updated insights and highlight areas where further research is required for a deeper molecular understanding of the role of mitochondria in β-cells and diabetes.

FUNDC1 modulates mitochondrial defects and pancreatic β-cell dysfunction under lipotoxicity

Insulin resistance and many metabolic disorders are causally linked to mitochondrial dysfunction or defective mitochondrial quality control. Mitophagy is a highly selective mechanism that recognizes and removes damaged mitochondria to maintain mitochondrial homeostasis. Here, we addressed the potential role of FUNDC1, a mediator of mitophagy, in pancreatic β-cell dysfunction under lipotoxicity. In pancreatic MIN6 cells, FUNDC1 deficiency aggravated palmitate-induced mitochondrial dysfunction, which led to cell death and insulin insensitivity. Interestingly, FUNDC1 overexpression prevented these cellular harms brought on by palmitate. In mice models, pancreatic-specific FUNDC1 overexpression alleviated high-fat diet (HFD)-induced insulin resistance and obesity. Mechanistically, pancreatic-specific overexpression of FUNDC1 ameliorated mitochondrial defects and endoplasmic reticulum (ER) stress upon HFD. Our research indicates that FUNDC1 plays an essential role in apoptosis and dysfunction of pancreatic β-cells via modulating lipotoxicity-induced mitochondrial defects.

Evaluation of Short-Term Insulin Pump for Treatment of Patients with Type 2 Diabetes Mellitus Complicated with Lower Extremity Arterial Disease in Endocrinology by Ultrasonography

This research aimed to explore the curative effect of short-term insulin pump in the treatment of type 2 diabetes mellitus (T2DM) patients with lower extremity arterial disease (LEAD) based on ultrasonography. 422 patients (220 males and 202 females) with T2DM in the hospital were selected, and they were randomly divided into control group (n = 211, oral hypoglycemic drugs or diet control, appropriate exercise to lower blood glucose) and experimental group (n = 211, insulin pump was used to reduce blood glucose). After 2 weeks, the therapeutic effect was evaluated by ultrasonography. The results showed that after two weeks of treatment, the difference in lumen intima between the two groups was statistically significant (P < 0.05). The intima-media thickness (IMT) values of the experimental group were 0.83 ± 0.03 mm, 0.62 ± 0.03 mm, and 0.41 ± 0.04 mm, respectively, which were significantly different from those of the control group (1.62 ± 0.54 mm, 1.23 ± 0.14 mm, and 0.78 ± 0.11 mm) (P < 0.05). There was obvious difference in low-density lipoprotein cholesterol (LDL-C) level between the experimental group (2.22 ± 0.46 mmol/L) and the control group (3.21 ± 0.62 mmol/L) (P < 0.05). The LEAD score of the experimental group was 5.51 ± 1.11, which was significantly different from that of the control group (7.08 ± 2.73) (P < 0.05). There was clear difference in LEAD score between the two groups under different course of disease (CD) (P < 0.05). Studies indicated that short-term application of insulin pump therapy could effectively improve the pathological changes of lower limbs in patients with T2DM, which had clinical application value.