1.The role of apolipoprotein C3 in the regulation of nonalcoholic fatty liver disease, glucose and lipid metabolism, and islet β cell function.
Shan YAN ; Zhi-Yong DING ; Yuan GAO ; Wang-Jia MAO ; Xiao-Yun CHENG
Acta Physiologica Sinica 2023;75(6):767-778
As a member of the apolipoprotein C (ApoC) family with a relatively high content, ApoC3 plays a major role in the regulation of triglyceride metabolism, and plays an important role in the occurrence and development of cardiovascular diseases, glucose and lipid metabolism disorders. Nonalcoholic fatty liver disease (NAFLD) refers to the accumulation of a large amount of fat in the liver in the absence of a history of chronic alcohol consumption or other damage to the liver. A large number of previous studies have shown that there is a correlation between the gene polymorphism and high expression of ApoC3 and NAFLD. In the context of hypertriglyceridemia (HTG), this article reviews the relationship between ApoC3 and NAFLD, glucose and lipid metabolism, and islet β cell function, showing that ApoC3 can not only inhibit lipoprotein lipase (LPL) and hepatic lipase (HL) activity, delay the decomposition of triglyceride in plasma to maintain the body's energy metabolism during fasting, but also be significantly increased under insulin resistance, prompting the liver to secrete a large amount of very low-density lipoprotein (VLDL) to induce HTG. Therefore, targeting and inhibiting ApoC3 might become a new approach to treat HTG. Increasing evidence suggests that ApoC3 does not appear to be an independent "contributor" to NAFLD. Similarly, our previous studies have shown that ApoC3 is not an independent factor triggering islet β cell dysfunction in ApoC3 transgenic mice, but in a state of excess nutrition, HTG triggered by ApoC3 high expression may exacerbate the effects of hyperglycemia and insulin resistance on islet β cell function, and the underlying mechanism remains to be further discussed.
Apolipoprotein C-III/genetics*
;
Non-alcoholic Fatty Liver Disease/pathology*
;
Glucose/metabolism*
;
Lipid Metabolism
;
Humans
;
Animals
;
Hypertriglyceridemia/metabolism*
;
Islets of Langerhans/metabolism*
2.Asiatic acid improves insulin secretion of β cells in type 2 diabetes through TNF- α/Mfn2 pathway.
Lu LI ; Wei WANG ; Qiang XU ; Mingzhu HUANG
Journal of Zhejiang University. Medical sciences 2023;52(2):185-194
OBJECTIVES:
To investigate the effects and molecular mechanisms of asiatic acid on β-cell function in type 2 diabetes mellitus (T2DM).
METHODS:
The T2DM model was established by high fat diet and streptozotocin injection in ICR mice, and the effects of asiatic acid on glucose regulation were investigated in model mice. The islets were isolated from palmitic acid-treated diabetic mice. ELISA was used to detect the glucose-stimulated insulin secretion, tumor necrosis factor (TNF)-α and interleukin (IL)-6. ATP assay was applied to measure ATP production, and Western blotting was used to detect protein expression of mature β cell marker urocortin (Ucn) 3 and mitofusin (Mfn) 2. The regulatory effects of asiatic acid on glucose-stimulated insulin secretion (GSIS) and Ucn3 expression were also investigated after siRNA interference with Mfn2 or treatment with TNF-α.
RESULTS:
Asiatic acid with the dose of 25 mg·kg-1·d-1 had the best glycemic control in T2DM mice and improved the homeostasis model assessment β index. Asiatic acid increased the expression of Mfn2 and Ucn3 protein and improved the GSIS function of diabetic β cells in vitro and in vivo (both P<0.05). Moreover, it improved the ATP production of islets of T2DM mice in vitro (P<0.05). Interfering Mfn2 with siRNA blocked the up-regulation of Ucn3 and GSIS induced by asiatic acid. Asiatic acid inhibited islet TNF-α content and increased Mfn2 and Ucn3 protein expression inhibited by TNF-α.
CONCLUSIONS
Asiatic acid improves β cell insulin secretion function in T2DM mice by maintaining the β cell maturity, which may be related to the TNF-α/Mfn2 pathway.
Mice
;
Animals
;
Insulin Secretion
;
Diabetes Mellitus, Type 2/drug therapy*
;
Islets of Langerhans/metabolism*
;
Tumor Necrosis Factor-alpha/metabolism*
;
Insulin/therapeutic use*
;
Diabetes Mellitus, Experimental
;
Mice, Inbred ICR
;
Glucose/therapeutic use*
;
Interleukin-6/metabolism*
;
RNA, Small Interfering/pharmacology*
;
Adenosine Triphosphate
;
GTP Phosphohydrolases/therapeutic use*
3.Effects of different routes of heparin on instant blood-mediated inflammatory reaction after portal vein islet transplantation.
Shengwang ZHANG ; Haixiong YAN ; Xiaoqian MA ; Wei ZHENG ; Wei WANG
Journal of Central South University(Medical Sciences) 2022;47(1):1-7
OBJECTIVES:
Heparin is mainly used as an anticoagulant in clinic, and it also has a certain anti-inflammatory effect. At present, after portal vein islet transplantation in diabetic patients, heparin is mainly infused through the peripheral veins of the limbs to achieve the purpose of anticoagulation and protection of the graft, rather than through the portal vein. In this study, animal experiments were conducted to investigate the effect of heparin infusion via the portal vein and marginal ear vein on the instant blood-mediated inflammatory reaction (IBMIR) after portal vein islet transplantation, which is the choice of anticoagulation methods for clinical islet transplantation to provide a basis for decision-making.
METHODS:
A total of 50 neonatal pigs (Xeno-1 type, 3-5 days) were selected. Islets were isolated and purified from the pancreas of neonatal pigs. Ten non-diabetic Landrace pigs (1.5-2.0 months) served as recipients, and 12 000 IEQ/kg neonatal porcine islets were transplanted into the liver through the portal vein. All recipients received bolus injection of 50 U/kg of heparin 10 minutes before transplantation. After the bolus injection of heparin, the experimental group received heparin via the portal vein [10 U/(kg·h), 5 recipients], and the control group received heparin via the marginal ear vein [10 U/(kg·h), 5 recipients]. The superior vena cava blood was collected from the 2 groups pre-operation at 1, 3, 24 h post-operation of the transplantation. The portal vein blood was collected from the experimental group at 1 and 3 h after the transplantation as well. The levels of complement C3a, C5a, thrombin-antithrombin complex (TAT), β-thromboglobulin (β-TG), and D-dimer as well as activated partial thromboplastin time (APTT) in superior vena cava blood from 1 and 3 h post-transplantation were detected in the 2 groups, and the levels of anti-Xa and anti-IIa in the portal vein and superior vena cava blood from 1 and 3 h post-transplantation in the experimental group were detected. Twenty four hours after the transplantation, the liver tissues in the 2 groups were collected for pathological examination to observe the inflammatory cell infiltration and peripheral thrombosis around the islets graft in liver.
RESULTS:
Before transplantation, there was no statistically significant difference in C3a, C5a, TAT, β-TG, D-dimer levels and APTT between the 2 groups (all P>0.05). At 1 and 3 h after transplantation, the C3a, TAT, and D-dimer levels in the experimental group were significant decreased than those in the control groups (all P<0.05), and at 3 h after transplantation the C5a was significant decreased than that in the control group (P<0.05). At 1 and 3 h after transplantation, the anti-Xa and anti-IIa levels in the portal vein blood were significantly increased than those in the superior vena cava blood in the experimental group (all P<0.05). Pathological results showed the presence of islet cell clusters in the liver blood vessels. The thrombus formation and neutrophil infiltration around islet graft was not obvious in the experimental group, while massive thrombus formation and neutrophil infiltration in the control group.
CONCLUSIONS
Compared with marginal ear vein infusion of heparin, the direct infusion of heparin in the portal vein has a certain inhibitory effect on complement system, coagulation system activation and inflammatory cell infiltration in portal vein islet transplantation, which may attenuate the occurrence of IBMIR.
Animals
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Anticoagulants/therapeutic use*
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Heparin/therapeutic use*
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Humans
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Islets of Langerhans/pathology*
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Islets of Langerhans Transplantation/physiology*
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Portal Vein
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Swine
;
Vena Cava, Superior
4.Islet organoid as a promising model for diabetes.
Xiaofei ZHANG ; Zhuo MA ; Eli SONG ; Tao XU
Protein & Cell 2022;13(4):239-257
Studies on diabetes have long been hampered by a lack of authentic disease models that, ideally, should be unlimited and able to recapitulate the abnormalities involved in the development, structure, and function of human pancreatic islets under pathological conditions. Stem cell-based islet organoids faithfully recapitulate islet development in vitro and provide large amounts of three-dimensional functional islet biomimetic materials with a morphological structure and cellular composition similar to those of native islets. Thus, islet organoids hold great promise for modeling islet development and function, deciphering the mechanisms underlying the onset of diabetes, providing an in vitro human organ model for infection of viruses such as SARS-CoV-2, and contributing to drug screening and autologous islet transplantation. However, the currently established islet organoids are generally immature compared with native islets, and further efforts should be made to improve the heterogeneity and functionality of islet organoids, making it an authentic and informative disease model for diabetes. Here, we review the advances and challenges in the generation of islet organoids, focusing on human pluripotent stem cell-derived islet organoids, and the potential applications of islet organoids as disease models and regenerative therapies for diabetes.
COVID-19
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Diabetes Mellitus/therapy*
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Humans
;
Islets of Langerhans
;
Organoids
;
SARS-CoV-2
5.Investigation on the mechanism of acupuncture in treatment of diabetes mellitus type 2 based on the network of islet macrophages-pancreatic adipose cells-islet β cells.
Yun LIU ; Tian-Cheng XU ; Zhi YU ; Bin XU
Chinese Acupuncture & Moxibustion 2022;42(4):433-436
To explore the possible new mechanism of acupuncture in the treatment of diabetes mellitus type 2 (T2DM) based on the islet inflammatory response. Islet macrophages, pancreatic adipose cells and islet β cells all participate in the pathogenesis of T2DM, and the three could form a network interaction. Acupuncture could regulate the functional phenotype of islet macrophages, improve the ectopic deposition of pancreatic adipose and repair the function of islet β cells, and play a unique advantage of overall regulation. It is suggested that acupuncture can be a potential treatment strategy for T2DM.
Acupuncture Therapy
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Diabetes Mellitus, Type 2/therapy*
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Humans
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Insulin-Secreting Cells/pathology*
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Islets of Langerhans/pathology*
;
Macrophages
6.Jiangtang Sanhuang tablet inhibits endoplasmic reticulum stress and autophagy in diabetic mouse islet cells.
Journal of Southern Medical University 2022;42(9):1317-1323
OBJECTIVE:
To investigate effects of Jiangtang Sanhuang tablet (JTSHT) for regulating blood glucose and alleviating islet cell damage in db/db mice and its protective effects against endoplasmic reticulum stress (ERS) and autophagy induced by glycolipid toxicity.
METHODS:
Forty db/db mice were randomized into 4 groups for daily intragastric administration of saline, JTSHT of 2.64 and 1.32 g/kg, and metformin at 0.225g/kg for 8 weeks, using 10 C57BL/6J mice as the normal control. After the treatments, the metabolic indexes of the mice were measured, and morphological changes of the islet cells were observed. A mouse islet cell line (MIN6) was exposed to high glucose (22 mmol/L glucose) and 0.1 mmol/L palmitic acid, followed by treatment with the sera from JTSHT- or saline- treated SD rats, alone or in combination with SP600125, and the changes in cell apoptosis, ERS and autophagy were evaluated using flow cytometry, RT-qPCR and Western blotting.
RESULTS:
In db/db mice, treatment with JTSHT significantly improved glucose and lipid metabolism (P < 0.05) and suppressed progressive weight gain (P < 0.05) without significant effect on drinking water volume (P > 0.05). JTSHT was also found to promote repair of islet cell injuries. In the cell experiments, high glucose exposure significantly increased apoptosis rate of MIN6 cells (P < 0.05), which was obviously lowered by treatment with JTSHT-treated rat serum (P < 0.05). Western blotting showed that JTSHT significantly reduced the level of ERS and autophagy caused by glycolipid toxicity in MIN6 cells (P < 0.05). Interference with ERS using SP600125 significantly attenuated the protective effect of JTSHT against MIN6 cell injury, apoptosis and autophagy induced by glycolipid toxicity (P < 0.05).
CONCLUSION
JTSHT has protective effects against glycolipid toxicity in MIN6 cells possibly by inhibiting ERS and autophagy.
Animals
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Anthracenes
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Apoptosis
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Autophagy
;
Blood Glucose
;
Diabetes Mellitus
;
Drinking Water
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Drugs, Chinese Herbal
;
Endoplasmic Reticulum Stress
;
Glucose/pharmacology*
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Glycolipids/pharmacology*
;
Islets of Langerhans
;
Metformin
;
Mice
;
Mice, Inbred C57BL
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Palmitic Acid/pharmacology*
;
Tablets/pharmacology*
7.Acquisition and application of functional pancreatic β cells: a review.
Guiqiyang XIANG ; Qinggui LIU ; Yiping HU ; Minjun WANG ; Fei CHEN
Chinese Journal of Biotechnology 2022;38(9):3316-3328
Insulin is produced and secreted by pancreatic β cells in the pancreas, which plays a key role in maintaining euglycemia. Insufficient secretion or deficient usage of insulin is the main cause of diabetes mellitus (DM). Drug therapy and islets transplantation are classical treatments for DM. Pancreatic β cell replacement therapy could help patients to get rid of drugs and alleviate the problem of lacking in transplantable donors. Pancreatic β-like cells can be acquired by cell reprogramming techniques or directed induction of stem cell differentiation. These cells are proved to be functional both in vitro and in vivo. Some hospitals have already performed clinical trials for pancreatic β cell replacement therapy. Functional pancreatic β-like cells, which obtained from in vitro pathway, could be a reliable source of cell therapy for treating DM. In this review, the approaches of obtaining pancreatic β cells are summarized and the remaining problems are discussed. Some thoughts are provided for further acquisition and application of pancreatic β cells.
Cell Differentiation
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Diabetes Mellitus/therapy*
;
Humans
;
Insulin/metabolism*
;
Insulin-Secreting Cells/metabolism*
;
Islets of Langerhans Transplantation
;
Pancreas/metabolism*
10.Adiponectin Ameliorated Pancreatic Islet Injury Induced by Chronic Intermittent Hypoxia through Inhibiting the Imbalance in Mitochondrial Fusion and Division.
Can HE ; Xi-Long ZHANG ; Qiang ZHANG ; Lu-Yao GE ; Wen-Xiao DING
Chinese Medical Sciences Journal 2021;36(3):225-233
Objective This study aimed to assess the protective value of adiponectin (APN) in pancreatic islet injury induced by chronic intermittent hypoxia (CIH). Methods Sixty rats were randomly divided into three groups: normal control (NC) group, CIH group, and CIH with APN supplement (CIH+APN) group. After 5 weeks of CIH exposure, we conducted oral glucose tolerance tests (OGTT) and insulin released test (IRT), examined and compared the adenosine triphosphate (ATP) levels, mitochondrial membrane potential (MMP) levels, reactive oxygen species (ROS) levels, enzymes gene expression levels of
Adiponectin/genetics*
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Animals
;
Hypoxia
;
Islets of Langerhans
;
Mitochondrial Dynamics
;
Rats
;
Rats, Wistar

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