Islet Injury Research Articles

Immune checkpoint inhibitors-related endocrinopathies exhibit increased severity in breast cancer patients: a real-world study.

This study aims to systematically evaluate the incidence of immune checkpoint inhibitors (ICIs)-related endocrinopathies and their onset time in patients with breast cancer (BC) in a real-world setting. An analysis was conducted on the medical records of 122 BC patients who underwent ICIs therapy at the Department of Breast Surgery, Guangdong Provincial People's Hospital, from April 2019 to September 2021. Follow-up data continued until October 2022. The research indicated that 60.66% of BC patients experienced ICI-related endocrinopathies. The endocrinopathies included pituitary injury (7.38%), primary thyroid dysfunction (34.43%), supranormal fasting blood glucose or glycohemoglobin levels (16.39%), and adrenal injury (2.46%). Subgroup analyses were further performed based on clinical characteristics, demonstrated variability in the incidence of ICI-related endocrinopathies. Notably, subpopulations harboring genetic mutations exhibited a markedly higher prevalence of hypophysitis, as evidenced by a statistically significant association (P = 0.022). Similarly, individuals with HER2 positivity were found to have a significantly increased incidence of pancreatic islet injury (P = 0.023). Moreover, the study documented that the median onset times of ICIs-related endocrinopathies in pituitary, thyroid, pancreatic, and adrenal damage were 264, 184, 99 and 141 days, respectively, which were substantially longer compared to previous reports involving other tumors. Remarkably, even after 500 days of initiating ICI therapy, new cases of ICI-related endocrine disorders continue to emerge, suggesting a situation of delayed onset of ICI-related endocrinopathies in BC patients. The retrospective analysis confirmed a higher incidence and longer median onset time of ICI-related endocrinopathies in BC patients compared to other cancers. These outcomes underscore the critical need for regular and extended monitoring of endocrine functions in BC patients receiving ICI therapy, advocating for personalized monitoring approaches based on individual clinical profiles.

Ginseng extract improves pancreatic islet injury and promotes β-cell regeneration in T2DM mice.

Panax ginseng C. A. Mey. (Araliaceae; Ginseng Radix et Rhizoma), a traditional plant commonly utilized in Eastern Asia, has demonstrated efficacy in treating neuro-damaging diseases and diabetes mellitus. However, its precise roles and mechanism in alleviating type 2 diabetes mellitus (T2DM) need further study. The objective of this study is to explore the pharmacological effects of ginseng extract and elucidate its potential mechanisms in protecting islets and promoting β-cell regeneration. The T2DM mouse model was induced through streptozotocin combined with a high-fat diet. Two batches of mice were sacrificed on the 7th and 28th days following ginseng extract administration. Body weight, fasting blood glucose levels, and glucose tolerance were detected. Morphological changes in the pancreatic islets were examined via H & E staining. Levels of serum insulin, glucagon, GLP-1, and inflammatory factors were measured using ELISA. The ability of ginseng extract to promote pancreatic islet β-cell regeneration was evaluated through insulin & PCNA double immunofluorescence staining. Furthermore, the mechanism behind β-cells regeneration was explored through insulin & glucagon double immunofluorescence staining, accompanied by immunohistochemical staining and western blot analyses. The present research revealed that ginseng extract alleviates symptoms of T2DM in mice, including decreased blood glucose levels and improved glucose tolerance. Serum levels of insulin, GLP-1, and IL-10 increased following the administration of ginseng extract, while levels of glucagon, TNF-α, and IL-1β decreased. Ginseng extract preserved normal islet morphology, increased nascent β-cell population, and inhibited inflammatory infiltration within the islets, moreover, it decreased α-cell proportion while increasing β-cell proportion. Mechanistically, ginseng extract might inhibit ARX and MAFB expressions, increase MAFA level to aid in α-cell to β-cell transformation, and activate AKT-FOXM1/cyclin D2 to enhance β-cell proliferation. Our study suggests that ginseng extract may be a promising therapy in treating T2DM, especially in those with islet injury.

Effect of glycotoxicity and lipotoxicity on carbohydrate antigen 19 − 9 in the patients with diabetes

ObjectivesIn comparison to the subjects without diabetes, a greater concentration of serum carbohydrate antigen 19 − 9 (CA 19 − 9) was observed in the subjects with diabetes. Nevertheless, since the occurrence of abnormal CA 19 − 9 is not widespread among the whole diabetic population, this phenomenon has not attracted enough attention. The prevalence of abnormal CA 19 − 9 in hospitalized patients with diabetes was the focus of our research.MethodA total of 385 subjects with diabetes and 200 controls were enrolled and all had been tested the CA19-9 levels. Cases of cancers were excluded through examination and followup for 1 year.ResultsWe found that the rate of patients with abnormal CA19-9 level was 8.3%. The rate of patients with abnormal CA19-9 level was 14.0% in the HbA1c ≥ 9% group, and 3.0% in the HbA1c < 9% group, 2.5% in the control group. There was no significant difference in the HbA1c < 9% group and the control group. A significant correlation between serum CA19-9 and both HbA1c and total cholesterol was observed, yet no difference in CRP level was observed between subjects with normal CA19-9 level and subjects with abnormal CA19-9 level. However, a significant difference in fasting C-peptide levels was observed between the two groups, p = 0.039.ConclusionThe percentage of patients with diabetes exhibiting elevated CA19-9 level is 14% in the HbA1c ≥ 9% diabetic patients, much higher than expected. The underlying mechanism may be related to islet injury caused by glycotoxicity and lipotoxicity. Strengths and limitations of the studyWe studied the rate of hospitalized diabetic patients with elevated CA 19 − 9 which were characterized with poorly controlled blood glucose. We found that the elevation of CA 19 − 9 was unexpectedly high in diabetic inpatients without development to cancer. The limitation of this study is that the underlying mechanism is not sufficiently studied.

Differences in glucose homeostasis and islet injury among diverse mice strains post acute pancreatitis

Diverse animal models have been used to study postpancreatitis diabetes mellitus (PPDM) development; however, no study has yet conducted a comparative analysis of the specific differences in glucose homeostasis and islet injury between these models. Therefore, we investigated the differences in pancreatic islet injury and glucose homeostasis among diverse strains in a cerulein-induced acute pancreatitis (AP) model to determine the appropriate animal model for PPDM. BALB/cJ, C57BL/6J, C57BL/6 N, and FVB/NJ mice were administered cerulein to induce AP. Serum amylase levels, pancreatic acinar injury, blood glucose homeostasis, islet function, and islet injury were measured and analyzed. All strains exhibited elevated amylase secretion post pancreatitis, and BALB/cJ, C57BL/6J, and C57BL/6 N mice exhibited sex-related differences. All strains exhibited pancreatic acinar injury post pancreatitis but mostly recovered within 15 days. Overall, glucose homeostasis remained balanced post pancreatitis in all strains compared to that in the control groups, except in FVB/NJ male and female mice, which exhibited an imbalance in glucose homeostasis on day 7 post pancreatitis. All the strains, except BALB/cJ mice, exhibited a decline in Homeostasis model assessment-β(HOMA-β) values post pancreatitis, with significant decrease in C57BL/6J females and FVB/NJ males. Islet size decreased post pancreatitis in all strains, except BALB/cJ mice. Pancreatic islet insulin secretion levels significantly decreased in male FVB/NJ mice post pancreatitis onset and did not recover within 15 days. Therefore, FVB/NJ male mice are a useful model for studying PPDM.

Effects of Extracellular Vesicles Derived from Human Umbilical Cord Blood Mesenchymal Stem Cells on Cell Immunity in Nonobese Mice.

Autoimmune responses are the most important pathogenic mechanisms underlying type 1 diabetes (T1D). Extracellular vesicles (EVs) derived from mesenchymal stem cells (MSCs) have immunomodulatory effects. In this study, we investigated whether EVs derived from human umbilical cord MSCs (HucMSC-EVs) have treatment effects on nonobese diabetic (NOD) mice as model of T1D. HucMSC-EVs were isolated from human umbilical cord MSCs and characterized. NOD mice (aged 4 weeks) were administered with HucMSC-EVs or the same volume of phosphate-buffered saline (PBS) via caudal vein injection twice per week. After 8 weeks of treatment, blood, spleen, and pancreatic samples were collected. Mouse blood glucose levels and body weights were measured during treatment, and insulin concentration and inflammatory cytokine levels were analyzed by enzyme-linked immunosorbent assay (ELISA). Hematoxylin and eosin (H&E) staining and immunohistochemistry (IHC) staining were used to evaluate pathological changes in mouse islets. T lymphocyte subsets were evaluated by flow cytometry, while quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot (WB) analyses were used to detect the expression of transcription factor and inflammatory cytokines. Our data indicated that HucMSC-EVs treatment reduced blood glucose levels and increased insulin concentration in NOD mice. Levels of interleukin-2 (IL-2), IL-4, and IL-10 were significantly increased and those of IL-1β and interferon-γ (IFN-γ) significantly decreased in the HucMSC-EVs group. The positive ratio of CD4+ T lymphocyte subsets decreased after intravenous injection of HucMSC-EVs, in which the proportion of Th2 cells increased and that of Th1 decreased. GATA-3 and IL-2, IL-4 and IL-10 expression levels were upregulated in spleen on treatment with HucMSC-EVs, whereas those of T-bet and IFN-γ were downregulated. In addition, more inflammatory cell infiltration was detected in the pancreas of control group mice than those treated with HucMSC-EVs. IHC staining showed that Fas/FasL expression and distribution in control group pancreas were higher than those in the HucMSC-EVs group. Together, our findings indicate that HucMSC-EVs have potential to prevent islet injury via T cell immune responses by adjusting the Th1/Th2 ratio to regulate secretion of inflammatory factors.

Leukotriene B4 receptor 2 governs macrophage migration during tissue inflammation

Chronic inflammation is the underlying cause of many diseases, including type 1 diabetes, obesity, and non-alcoholic fatty liver disease. Macrophages are continuously recruited to tissues during chronic inflammation where they exacerbate or resolve the pro-inflammatory environment. Although leukotriene B4 receptor 2 (BLT2) has been characterized as a low affinity receptor to several key eicosanoids and chemoattractants, its precise roles in the setting of inflammation and macrophage function remain incompletely understood. Here we used zebrafish and mouse models to probe the role of BLT2 in macrophage function during inflammation. We detected BLT2 expression in bone marrow derived and peritoneal macrophages of mouse models. Transcriptomic analysis of Ltb4r2-/- and WT macrophages suggested a role for BLT2 in macrophage migration, and studies invitro confirmed that whereas BLT2 does not mediate macrophage polarization, it is required for chemotactic function, possibly mediated by downstream genes Ccl5 and Lgals3. Using a zebrafish model of tailfin injury, we demonstrated that antisense morpholino-mediated knockdown of blt2a or chemical inhibition of BLT2 signaling impairs macrophage migration. We further replicated these findings in zebrafish models of islet injury and liver inflammation. Moreover, we established the applicability of our zebrafish findings to mammals by showing that macrophages of Ltb4r2-/- mice have defective migration during lipopolysaccharide stimulation invivo. Collectively, our results demonstrate that BLT2 mediates macrophage migration during inflammation, which implicates it as a potential therapeutic target for inflammatory pathologies.

Protective effects of metformin on pancreatic β-cell ferroptosis in type 2 diabetes in vivo

Metformin (Met) is the recommended first-line therapeutic drug for type 2 diabetes mellitus (T2DM) and exerts protective effects on β-cell damage. Ferroptosis, a new form of cell death, is associated with pancreatic islet injury in patients with T2DM. However, the protective effects of Met treatment against β-cell damage through ferroptosis modulation remain under-reported. This study investigated the in vivo effects of Met treatment on pancreatic β-cell ferroptosis using two different diabetic mouse models, namely, low-dose streptozotocin (STZ) and high-fat diet (HFD)–induced diabetic mice and db/db mice. Met treatment significantly restored insulin release, reduced cell mortality, and decreased the overproduction of lipid-related reactive oxygen species in the islets of both STZ/HFD-induced diabetic mice and db/db mice. Administration of the Ras-selective lethal 3 injection significantly attenuated the antiferroptosis effects of Met. Mechanistically, Met treatment alleviated β-cell ferroptosis in T2DM, which was associated with the regulation of the GPX4/ACSL4 axis in the islets. In conclusion, our findings highlight the significance of ferroptosis in T2DM β-cell damage and provide novel insights into the protective effects of Met against islet β cells.

Antihyperlipidemic and Histopathological Pancreas Analysis of Muntingia calabura L. Fruit Extract on Alloxan-Induced Diabetic Mice

Hyperlipidemia is clinically manifested by high levels of Total Cholesterol (TC), Triglycerides (TG), Low Density Lipoprotein (LDL) and low levels of High Density Lipoprotein (HDL) in the blood. Antihyperlipidemic drugs available currently have adverse effects. One of the medicine plants with antihyperlipidemic properties with no side effects is Muntingia calabura fruit. The sample used for this research were 30 male mice were divided into 5 groups, i.e., a negative control, a diabetic control, a positive control group, and two treatment groups which were given 100 and 300mg/kg of M. calabura fruit extract every day for 14 days. Examination of TC, TG, HDL, LDL and histopathological pancreas were determined after administration of the extract orally for 14 days. The results demonstrated an administration of glibenclamide and M. calabura fruit could effectively reduce TC, TG and LDL and increase HDL compared to the diabetes control group (P&lt;0.05). In the diabetes control group, the mice given alloxan 150mg/kg showed a decrease in Langerhans islet density, vascularity, and islet injury compared to the normal control group. Mice given M. calabura fruit extract showed a significant increase in pancreatic Langerhans cells granulation and cell density. The conclusion of this research is M. calabura fruit extract showed improvements in lipid profile and pancreatic Langerhans cell regeneration. Therefore, the fruit extract of M. calabura is a potential antihyperlipidemic drug.

839-P: Alpha-1 Antitrypsin Augmentation Therapy in Chronic Pancreatitis Patients Undergoing Total Pancreatectomy and Islet Autotransplantation

Stress-induced islet graft loss reduces the efficacy of islet transplants. In this single-center, randomized, double-blind, and controlled clinical trial, we evaluated the safety and efficacy of human alpha-1 antitrypsin (AAT) infusion in chronic pancreatitis (CP) patients undergoing total pancreatectomy and islet autotransplantation (TP-IAT) at the Medical University of South Carolina. Among 48 qualified subjects randomized in a 1:2 (placebo vs AAT) ratio, 43 received TP-IAT. Subjects were given saline or AAT infusion at 60mg/kg weekly for 4 weeks and were followed for 12 months. The primary efficacy endpoint was the islet function measured by the C-peptide area under the curve during a mixed meal tolerance test (MMTT) at Month 12 (M12). Adverse events (AEs) were measured throughout the study. Safety, glycemic control, insulin use, and quality of life (QoL) were compared between groups. Safety evaluation showed no significant differences in the types and severity of participant AEs. The primary efficacy outcome was not significantly different between groups. Baseline characteristics including age, body weight, BMI, HbA1C, etc, were comparable in the randomized populations. The oxygen consumption rate before the transplant was higher in the AAT group. Serum C-peptide (an indicator of islet death) was lower in the AAT group, suggesting less islet injury. AAT subjects trended toward better SF-12 physical QoL and lower insulin use at both 75 and 365 days post-IAT. Despite intensive efforts to get participants to return for the Day 365 MMTT, only 10/14 (71%) in the placebo group and 18/29 (62%) in the AAT group returned for this test. Although we did not observe a statistical difference in islet function using AAT therapy, we gained a better understanding of this patient population. Minimizing numbers of follow-up visits, use of fewer doses of medication with higher doses, and providing travel are all important for future clinical trials in TP-IAT. Disclosure H. Wang: None. W. Gou: None. D. Adams: None. K. Morgan: Speaker's Bureau; Johnson &amp; Johnson Medical Devices Companies. P.J. Nietert: None. J. Hirsch: None. C. Strange: None. Funding National Institute of Diabetes and Digestive and Kidney Diseases (1R01DK105183, DK120394, DK118529); U.S. Department of Veterans Affairs (I01BX004536 to H.W.)

Genetic lineage tracing reveals stellate cells as contributors to myofibroblasts in pancreas and islet fibrosis

Pancreatic stellate cells (PSCs) are suggested to play an important role in the development of pancreas and islet fibrosis. However, the precise contributions and solid invivo evidence of PSCs to the fibrogenesis remain to be elucidated. Here, we developed a novel fate-tracing strategy for PSCs by vitamin A administration in Lrat-cre; Rosa26-tdTomato transgenic mouse. The results showed that stellate cells give rise to 65.7% of myofibroblasts in cerulein-induced pancreatic exocrine fibrosis. In addition, stellate cells in islets increase and contribute partly to myofibroblasts pool in streptozocin-induced acute or chronic islet injury and fibrosis. Furthermore, we substantiated the functional contribution of PSCs to fibrogenesis of pancreatic exocrine and islet in PSCs ablated mice. We also found stellate cells' genetic ablation can improve pancreatic exocrine but not islet fibrosis. Together, our data indicates that stellate cells are vital/partial contributors to myofibroblasts in pancreatic exocrine/islet fibrosis.

Ginsenoside Rg1 Improves Inflammation and Autophagy of the Pancreas and Spleen in Streptozotocin-Induced Type 1 Diabetic Mice.

Ginsenoside Rg1 (Rg1) is one of the key bioactive components of the precious Traditional Chinese Medicine that has been used to treat diabetes in China. Ginsenosides have been reported to protect diabetics from tissue damage, inflammation, and insulin resistance. Type 1 diabetes (T1D) is an organ-specific autoimmune disease that occurred frequently among adolescents over the world, its development was related to inflammation and β-cells immunodeficiency. The aim of this study is to explore the biological mechanism of Rg1 on inflammation and autophagy of β-cells in T1D and its therapeutic potential. The model of T1D mice was established by injecting Streptozotocin (STZ) (55 mg/kg) or citric acids once a day for 5 days and from the fourth day of injection, mice were administered with Rg1 (20 mg/kg) or saline by gavage once a day for 12 days. Hematoxylin-eosin staining, immunofluorescence, ELISA, quantitative real-time PCR, and Western blot were used to observe the histopathological changes, inflammatory factor levels, and autophagy markers after administration of ginsenoside Rg1. Compared to the T1D mice, Rg1 improved the weight (p < 0.05) and blood glucose (p < 0.01) of mice, advanced the injury and apoptosis of β-cells in islets (p < 0.01), and markedly inhibited the protein expression degrees of CD45, CXCL16, ox-LDL, and TF in the pancreas and spleens (p < 0.01), also activated the degrees of insulin in serum (p < 0.01). Besides, in T1D mice' pancreas and spleen, Rg1 markedly repressed the IL-1β, TNF-α, and NOS2 mRNA levels (p < 0.05 or p < 0.01), inhibited the CXCL16, NF-κB, and TF proteins (p < 0.05 or p < 0.01), while elevating the ratio of LC3 II/I (p < 0.01) and P62 (p < 0.05) protein level. This study proved that Rg1 protected mice against T1D possibly by improving islet injury and tissue inflammation, raising serum insulin, and tissue autophagy marker.

Onopordum acanthium L. extract attenuates pancreatic β-Cells and cardiac inflammation in streptozocin-induced diabetic rats.

Methanolic extract from Onopordum acanthium L. leaves (MEOAL) has been discovered to treat diabetic complications. The objective of this study is to evaluate the ameliorative role of MEOAL on pancreatic islet injury and myocardial inflammation in diabetic rats. Forty male Wister albino rats were allocated into five groups of eight rats each. Group A was the negative control group. Single intraperitoneal injection of streptozocin (50mg/kg) were used for the four experimental groups. Group B served as the positive control group. The rats in Groups C, D, and E received glibenclamide (5mg/kg), MEOAL (200, and 400 mg/kg) respectively, for eight weeks. Group C served as the standard drug group. High performance liquid chromatography (HPLC) and 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) assays for antioxidant activity were conducted in MEOAL. In silico study, calculation of molecular binding energy (DG), and inhibition constant (pKi) of bioactive constituents in MEOAL were performed. Administration of MEOAL significantly increases insulin content in β-cells with a marked enhancement of pancreatic islet structure, resulting in a significant reduction of blood glucose level and body weight loss. MEOAL treatment suppressed the increase of inflammatory cell score in myocardial tissue with an elevation of M2 -like macrophage. The phytochemical studies recorded the presence of six polyphenols, including catechin, kaempferol, syringic acid, p-coumaric acid, epicatechin and gallic acid in MEOAL. Moreover, the antioxidant activity of the extract was greater than that of standard ascorbic acid. The docking studies of the ligands Catechin, kaempferol and epicatechin with proteins showed high affinities with various targets related in β-Cells and cardiac inflammation. The attenuation of pancreatic β-Cells damage and cardiac inflammation by MEOAL could be attributed to the presence of Catechin, kaempferol and epicatechin which have high affinities with the receptors namely pancreatic alpha-amylase, glucokinase, COX-2, and COX-1.

High Dietary Iron in Western Diet-Fed Male Rats Causes Pancreatic Islet Injury and Acute Pancreatitis

BackgroundHigh dietary iron has been linked to an increased type 2 diabetes risk. We have previously shown that intrauterine growth restriction (IUGR) and feeding a Western diet (WD) to male Sprague-Dawley rats independently, as well as together, cause pancreatic islet inflammation, fibrosis, and hemosiderosis. ObjectivesTo investigate whether iron has a role in the pathogenesis of this inflammatory islet injury caused by IUGR and WD intake. MethodsMale Sprague-Dawley offspring of bilateral uterine artery ligated (IUGR) and sham-operated (Sham) dams, fostered to nonoperated dams, were fed a WD [45% sucrose, 19.4% protein and 23% fat (w/w)] containing low iron (LI, 20 mg/kg) or high iron (HI, 500 mg/kg) from weaning. Four groups were studied: Sham-LI, Sham-HI, IUGR-LI, and IUGR-HI. Serial measurements of rat body weight, blood glucose, lipids and insulin, an intraperitoneal glucose tolerance test (age 13 wk), and histological analysis of pancreas and liver (age 14 wk) were recorded. The effects of iron, IUGR, and their interaction, on these measurements have been analyzed. ResultsWD with HI compared with LI caused an 11% greater weight gain by age 14 wk (P < 0.001), impaired glucose tolerance [AUC for glucose (G-AUC) 17% higher; P < 0.001), acute pancreatitis (17/18, HI; 6/17, LI; P < 0.001), pancreas-associated fat necrosis and saponification (7/18, HI; 0/17 LI; P < 0.01), and a trend to islet fibrotic injury (7/18, HI; 1/17 LI; P = 0.051). Although pancreatic and hepatic steatosis was evident in almost all WD-fed rats, pancreatic and hepatic iron accumulation was prevalent only in HI-fed rats (P < 0.0001 for both), being only mild in the livers. IUGR, independent of dietary iron, also caused impairment in glucose tolerance (G-AUC: 17% higher; P < 0.05). ConclusionsA postweaning WD containing HI, independent of IUGR, causes acute pancreatitis and islet injury in Sprague-Dawley rats suggesting a role of dietary iron in the development of steatopancreatitis.

Effect of Codonopsis Radix and Polygonati Rhizoma on the regulation of the IRS1/PI3K/AKT signaling pathway in type 2 diabetic mice.

Codonopsis Radix and Polygonati Rhizoma (CRPR) has a good hypoglycemic effect. The aims of the present study were to investigate the effect of CRPR on high-fat/high-sugar diet (HFHSD)- and streptozotocin (STZ)-induced type 2 diabetes mellitus (T2DM) mice as well as to investigate the involved mechanism. A T2DM mouse model was generated by combining HFHSD and STZ. After the model was established, normal and model groups received the same volume of normal saline intragastrically, and the negative control group was treated with metformin (200 mg/kg·BW). The low, medium, and high CRPR groups received four consecutive weeks of oral gavage with CRPR doses of 2.5, 5, and 10 g/kg·BW, respectively, during the course of the study. Body weight and fasting blood glucose (FBG) were measured on a weekly basis. Enzyme-linked immunosorbent assay (ELISAs) were used to evaluate the serum and liver samples. Hematoxylin and eosin (H&E) staining was utilized to observe the pathological status of the liver and pancreas. Western blot (WB) analysis was performed to evaluate the protein expression levels of PI3K, p-PI3K, AKT, and p-AKT. Compared to model mice, each treatment group had significantly elevated levels of FBG, total cholesterol (TC), and triacylglycerol (TG) (P<0.01 and P<0.05, respectively). The levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were significantly reduced in the treatment groups compared to the model group (P<0.01). Compared to the model group, fasting insulin (FINS) levels were elevated in all groups of CRPR (P<0.05), and there were significantly higher levels of high-density lipoprotein cholesterol (HDL-C) in both the low-dose and high-dose CRPR groups (P<0.05). H&E staining indicated that CRPR treatment reduced organ enlargement, improved liver lipid accumulation, and repaired islet injury in T2DM mice. Moreover, WB analysis demonstrated that all CRPR groups significantly upregulated the protein expression of IRS1, p-GSK3β, PI3K, p-Akt and p-FOXO1(P<0.05) as well as significantly downregulated p-IRS1 and FOXO1 protein expression (P<0.05). The present study demonstrated that CRPR effectively improves the metabolic disturbance of lipids, repairs damaged liver tissues, repairs damaged pancreatic tissues, and reduces insulin resistance (IR) in T2DM mice. The mechanism of action may be associated with upregulation of the IRS1/PI3K/AKT signaling pathway and inhibition of IRS1 phosphorylation.

Ferroptosis as a Novel Determinant of β-Cell Death in Diabetic Conditions.

The main pathological hallmark of diabetes is the loss of functional β-cells. Among several types of β-cell death in diabetes, the involvement of ferroptosis remains elusive. Therefore, we investigated the potential of diabetes-mimicking factors: high glucose (HG), proinflammatory cytokines, hydrogen peroxide (H2O2), or diabetogenic agent streptozotocin (STZ) to induce ferroptosis of β-cells in vitro. Furthermore, we tested the contribution of ferroptosis to injury of pancreatic islets in an STZ-induced in vivo diabetic model. All in vitro treatments increased loss of Rin-5F cells along with the accumulation of reactive oxygen species, lipid peroxides and iron, inactivation of NF-E2-related factor 2 (Nrf2), and decrease in glutathione peroxidase 4 expression and mitochondrial membrane potential (MMP). Ferrostatin 1 (Fer-1), ferroptosis inhibitor, diminished the above-stated effects and rescued cells from death in case of HG, STZ, and H2O2 treatments, while failed to increase MMP and to attenuate cell death after the cytokines' treatment. Moreover, Fer-1 protected pancreatic islets from STZ-induced injury in diabetic in vivo model, since it decreased infiltration of macrophages and accumulation of lipid peroxides and increased the population of insulin-positive cells. Such results revealed differences between diabetogenic stimuli in determining the destiny of β-cells, emerging HG, H2O2, and STZ, but not cytokines, as contributing factors to ferroptosis and shed new light on an antidiabetic strategy based on Nrf2 activation. Thus, targeting ferroptosis in diabetes might be a promising new approach for preservation of the β-cell population. Our results obtained from in vivo study strongly justify this approach.

Islet Regeneration and Pancreatic Duct Glands in Human and Experimental Diabetes.

Contrasting evidence is present regarding the contribution of stem/progenitor cell populations to pancreatic regeneration in diabetes. Interestingly, a cell compartment with stem/progenitor cell features has been identified in the pancreatic duct glands (PDGs). The aims of the present study were to evaluate pancreatic islet injury and regeneration, and the participation of the PDG compartment in type 2 diabetic mellitus (T2DM) and in an experimental model of diabetes. Human pancreata were obtained from normal (N = 5) or T2DM (N = 10) cadaveric organ donors. Experimental diabetes was generated in mice by intraperitoneal injection of 150 mg/kg of streptozotocin (STZ, N = 10); N = 10 STZ mice also received daily intraperitoneal injections of 100 µg of human recombinant PDX1 peptide (STZ + PDX1). Samples were examined by immunohistochemistry/immunofluorescence or RT-qPCR. Serum glucose and c-peptide levels were measured in mice. Islets in T2DM patients showed β-cell loss, signs of injury and proliferation, and a higher proportion of central islets. PDGs in T2DM patients had a higher percentage of proliferating and insulin+ or glucagon+ cells compared to controls; pancreatic islets could be observed within pancreatic duct walls of T2DM patients. STZ mice were characterized by reduced islet area compared to controls. PDX1 treatment increased islet area and the percentage of central islets compared to untreated STZ mice but did not revert diabetes. In conclusion, T2DM patients show signs of pancreatic islet regeneration and involvement of the PDG niche. PDX1 administration could support increased endocrine pancreatic regeneration in STZ. These findings contribute to defining the role and participation of stem/progenitor cell compartments within the pancreas.

AANG Prevents Smad3-dependent Diabetic Nephropathy by Restoring Pancreatic β-Cell Development in db/db Mice.

Diabetic nephropathy (DN) is a major cause of end-stage kidney disease, where TGF-β1/Smad signaling plays an important role in the disease progression. Our previous studies demonstrated a combination of Traditional Chinese Medicine derived Smad7 agonist Asiatic Acid (AA) and Smad3 inhibitor Naringenin (NG), AANG, effectively suppressed the progression of renal fibrosis in vivo. However, its implication in type-2 diabetic nephropathy (T2DN) is still unexplored. Here, we detected progressive activation of Smad3 but reduction of Smad7 in db/db mice during T2DN development. Therefore, we optimized the dosage and the combination ratio of AANG to achieve a better rebalancing Smad3/Smad7 signaling for treatment of T2DN. Unexpectedly, preventive treatment with combined AANG from week 4 before the development of diabetes and T2DN effectively protected against the onset of T2DN. In contract, these inhibitory effects were lost when db/db mice received the late AANG treatment from 12-24 weeks. Surprisingly, preventive treatment with AANG ameliorated not only T2DN but also the primary disease type-2 diabetes (T2D) with relative normal levels of fasting blood glucose and HbA1c, and largely improving metabolic abnormalities especially on insulin insensitivity and glucose tolerance in db/db mice. Mechanistically, AANG effectively prevented both Smad3-mediated renal fibrosis and NF-κB-driven renal inflammation in the diabetic kidney in vivo and advanced glycation end-products (AGE) stimulated tubular epithelial mTEC cells in vitro. More importantly, we uncovered that preventive treatment with AANG effectively protected against diabetic-associated islet injury via restoring the β cell development in db/db mice. Taken together, we discovered that the early treatment with combined AANG can effectively protect against the development of T2D and T2DN via mechanism associated with protection against Smad3-depenedent islet injury.

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The primary cells that participate in islet transplantation are the endocrine cells. However, in the islet microenvironment, the endocrine cells are closely associated with the neurovascular tissues consisting of the Schwann cells and pericytes, which form sheaths/barriers at the islet exterior and interior borders. The two cell types have shown their plasticity in islet injury, but their roles in transplantation remain unclear. In this research, we applied 3-dimensional neurovascular histology with cell tracing to reveal the participation of Schwann cells and pericytes in mouse islet transplantation. Longitudinal studies of the grafts under the kidney capsule identify that the donor Schwann cells and pericytes re-associate with the engrafted islets at the peri-graft and perivascular domains, respectively, indicating their adaptability in transplantation. Based on the morphological proximity and cellular reactivity, we propose that the new islet microenvironment should include the peri-graft Schwann cell sheath and perivascular pericytes as an integral part of the new tissue.

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The primary cells that participate in islet transplantation are the endocrine cells. However, in the islet microenvironment, the endocrine cells are closely associated with the neurovascular tissues consisting of the Schwann cells and pericytes, which form sheaths/barriers at the islet exterior and interior borders. The two cell types have shown their plasticity in islet injury, but their roles in transplantation remain unclear. In this research, we applied 3-dimensional neurovascular histology with cell tracing to reveal the participation of Schwann cells and pericytes in mouse islet transplantation. Longitudinal studies of the grafts under the kidney capsule identify that the donor Schwann cells and pericytes re-associate with the engrafted islets at the peri-graft and perivascular domains, respectively, indicating their adaptability in transplantation. Based on the morphological proximity and cellular reactivity, we propose that the new islet microenvironment should include the peri-graft Schwann cell sheath and perivascular pericytes as an integral part of the new tissue.

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The primary cells that participate in islet transplantation are the endocrine cells. However, in the islet microenvironment, the endocrine cells are closely associated with the neurovascular tissues consisting of the Schwann cells and pericytes, which form sheaths/barriers at the islet exterior and interior borders. The two cell types have shown their plasticity in islet injury, but their roles in transplantation remain unclear. In this research, we applied 3-dimensional neurovascular histology with cell tracing to reveal the participation of Schwann cells and pericytes in mouse islet transplantation. Longitudinal studies of the grafts under the kidney capsule identify that the donor Schwann cells and pericytes re-associate with the engrafted islets at the peri-graft and perivascular domains, respectively, indicating their adaptability in transplantation. Based on the morphological proximity and cellular reactivity, we propose that the new islet microenvironment should include the peri-graft Schwann cell sheath and perivascular pericytes as an integral part of the new tissue.