Islet transplantation tolerance in animals with defined histocompatibility and diabetes

Advances in organ transplantation benefit from development of genetically inbred animal strains with defined histocompatibility and cell-specific markers to distinguish donor and host cell subsets. For studies of pancreatic islet transplantation tolerance in diabetes, an invariant method to ablate host β cells and induce diabetes would provide an immense additional advantage. Here we detail development and use of B6 RIP-DTR mice , an immunocompetent line permitting diabetes induction with 100% penetrance. This inbred line is homozygous for the C57BL/6J major histocompatibility complex (MHC) haplotype and expresses the mutant CD45.1 allele in the hematopoietic lineage. β cell-specific expression of a high-affinity receptor for diphtheria toxin (DT) permits experimental β cell ablation and diabetes induction after DT administration. Diabetes reversal for over one year was achieved after transplantation with congenic C57BL/6J islets, but not with MHC-mismatched BALB/c islets, which were rapidly rejected. In summary, the generation of a C57BL/6J congenic line harboring the CD45.1 allele and Ins2-HBEGF transgene should advance studies of islet transplantation tolerance and mechanisms to improve islet engraftment and function, thereby optimizing development of cell replacement strategies for diabetes mellitus.

Streptozotocin-induced type 1 and 2 diabetes in rodents: a model for studying diabetic cardiac autonomic neuropathy

Background: Several animal models are continually being developed to study diabetic complication. Several conflicting regimen for diabetes induction exist in the literature with varying dose strength and regimen for different study interest in diabetes. This study aims to show the effect of high dose streptozotocin (STZ) on the one hand compared with multiple low doses after high fat diet induction on diabetic cardiac autonomic neuropathy (DCAN). Methodology: Eighty-four Wistar rats were used to demonstrate DCAN induction using 2 approaches one for T1DM (STZ 50mg/kg) and the other for T2DM (HFD for 8 weeks with STZ 25mg/Kg daily for five days). DCAN features were assessed using invasive biomarkers, histology patterns and cardiac nerve densities. Results: Diabetes induction rate was 76% and 89% in T1DM and T2DM model respectively. T1DM group had significant weight loss, reduced c-peptide, and insulin level post induction. The T2DM additionally showed significantly higher total cholesterol and Homeostatic model assessment (HOMA) compared with control. Serum levels of catecholamine, choactase, nerve growth factor and cardiac nerve density confirms development of DCAN. Conclusion: High single dose of STZ and HFD with multiple low doses of STZ may be recommended for DCAN study in T1DM and T2DM rat model respectively. Keywords: Diabetic cardiac autonomic neuropathy; Diabetes mellitus; Heart rate variability; Streptozotocin.

Therapeutic Potential Of Human Neural Precursor Cells in Diabetic Retinopathy – Preclinical Model

This study aimed to evaluate cell therapy with human neural precursor cells (hNPCs) in diabetic retinopathy (DR) Wistar rats, induced to diabetes by intraperitoneal injection with streptozotocin. Wharton's Jelly Mesenchymal stem cells (WJ-MSCs) were isolated, expanded, and seeded onto a biopolymer substrate without growth factors to develop neurospheres to obtain the hNPCs, characterized by immunocytochemistry. The animals were divided into three groups; non-diabetic (ND) n = four; diabetic without treatment (DM) n = nine; and diabetic with cell therapy (DM + hNPCs) n = nine. After eight weeks of diabetes induction and verified DR, intravitreal injection of hNPCs (1 x 106 cel/µL) was performed in the DM + hNPCs group. Optical Coherence Tomography (OCT) and Electroretinography (ERG) evaluations were done before and after diabetes induction and after cell therapy. Eye enucleation occurred four weeks after treatment for the histopathological and immunohistochemistry analyses. In the treated group, there was the repair of the retinal structures and their arrangements. hNPCs increased the thickness of neuroretina layers, especially in the ganglion cell and photoreceptor layers. The results indicate that hNPCs reduced DR progression by a neuroprotective effect and promoted retinal repair, making them potential candidates for regeneration of the neuroretinal tissue.

Carvedilol Exerts Neuroprotective Effect on Rat Model of Diabetic Neuropathy

Diabetic neuropathy (DN) commonly occurs in diabetics, affecting approximately 50% of both type 1 and 2 diabetic patients. It is a leading cause of non-traumatic amputations. Oxidative stress could play a key role in the pathophysiology of DN. This study aimed to investigate the potential neuroprotective effect of carvedilol on STZ-induced DN in rats. Thirty male Sprague Dawley rats (weighing 200–250 g) were randomly divided into five groups (six/group), where group 1 (negative control) received only the vehicle (0.5% of carboxymethyl cellulose orally 1 ml/kg). DN was induced by a single injection of remaining rats with streptozotocin (STZ; 50 mg/kg, i.p.). After diabetes induction, group 2 served as the diabetic untreated animals; while groups 3 and 4 were treated with carvedilol (1 and 10 mg/kg/d, orally, respectively). Group 5 received a-lipoic acid as a reference neuroprotective (100 mg/kg/d, orally). All treatments were continued for 45 days after diabetes induction, followed by behavioural tests. After sacrificing the animals, dorsal root ganglia, and sciatic nerves were collected for histopathological examination and biochemical assessments. Briefly, STZ administration caused cold allodynia, induced oxidative stress, and increased nerve growth factor (NGF) concentration. Nevertheless, carvedilol improved the behavioural tests, ameliorated the oxidative imbalance as manifested by reducing malondialdehyde, restoring glutathione content, and superoxide dismutase activity. Carvedilol also decreased NGF concentration in DRG homogenate. In conclusion, this study demonstrates the neuroprotective effect of carvedilol in an experimentally induced DN rat model through–at least partly–its antioxidant effect and reduced NGF concentration in DRG.

Fetomaternal Outcome After Induction of Labor at Term in Patients with Gestational Diabetes

Objective: The objective of study is to determine the fetomaternal outcome after induction of labour at term in patients with gestational diabetes. Methods: This study was conducted at department of Obstetrics and gynecology of Hameed Latif hospital, Lahore, Pakistan from March 2019 to October 2019. Seventy-nine pregnant women with gestational diabetes at term, undergoing induction of labour were included in the study after informed consent. Maternal outcome was studied by classifying different modes of delivery. Fetal outcome was measured on basis of APGAR scores and neonatal weight. Results: There were 55/79 vaginal deliveries making vaginal delivery rate to be 66.9%. Mean birth weight of neonates was 3.15 + 0.558 kg. Mean APGAR Score at 1 min and 5 minutes were 7.7 + 0.6193 and 8.8 + 0.4793 respectively. Conclusion: Labor induction in patients with gestational diabetes is associated with lower rate of cesarean delivery with a satisfactory fetal outcome. Key Words: Gestational diabetes, induction of labour, maternal outcome, fetal outcome How to cite: Imran S., Dr., Noreen. A, Khayam. I., Arjmand A., Ghafoor R., Khalique F. Fetomaternal Outcome After Induction of Labor at Term in Patients with Gestational Diabetes. Esculapio 2021;17(01):49-54

Which Hyperglycemic Model of Zebrafish (Danio rerio) Suites My Type 2 Diabetes Mellitus Research? A Scoring System for Available Methods

Despite extensive studies on type 2 diabetes mellitus (T2DM), there is no definitive cure, drug, or prevention. Therefore, for developing new therapeutics, proper study models of T2DM is necessary to conduct further preclinical researches. Diabetes has been induced in animals using chemical, genetic, hormonal, antibody, viral, and surgical methods or a combination of them. Beside different approaches of diabetes induction, different animal species have been suggested. Although more than 85% of articles have proposed rat (genusRattus) as the proper model for diabetes induction, zebrafish (Danio rerio) models of diabetes are being used more frequently in diabetes related studies. In this systematic review, we compare different aspects of available methods of inducing hyperglycemia referred as T2DM in zebrafish by utilizing a scoring system. Evaluating 26 approved models of T2DM in zebrafish, this scoring system may help researchers to compare different T2DM zebrafish models and select the best one regarding their own research theme. Eventually, glyoxalase1 (glo1−/−) knockout model of hyperglycemia achieved the highest score. In addition to assessment of hyperglycemic induction methods in zebrafish, eight most commonly proposed diabetic induction approval methods are suggested to help researchers confirm their subsequent proposed models.

Influence of three BALB/c substrain backgrounds on the skin tumor induction efficacy to DMBA and TPA cotreatment

Differences in responsiveness of BALB/c substrains have been investigated in various fields, including diabetes induction, corpus callosum deficiency, virus-induced demyelinating disease, aggressive behavior and osteonecrosis. However, induction efficacy of skin tumor remains untried. We therefore investigated the influence of BALB/c substrain backgrounds on the skin tumor induction efficacy in response to DMBA (7,12-Dimethylbenz[a]anthracene) and TPA (12-O-tetradecanoylphorbol-13-acetate) cotreatment. Alterations in the levels of tumor growth related factors, histopathological structure, and the expression to tumor related proteins were measured in three BALB/c substrains (BALB/cKorl, BALB/cA and BALB/cB) after exposure to DMBA (25 μg/kg) and three different doses of TPA (2, 4 and 8 μg/kg). The average number and induction efficacy of tumors in response to DMBA+TPA treatment were significantly greater in the BALB/cKorl substrain than in BALB/cA and BALB/cB. However, cotreatment with DMBA+TPA induced similar responses for body and organ weights of all three substrains. Few differences were detected in the serum analyzing factors, while similar responsiveness was observed for blood analyzing factors after DMBA+TPA treatment. Furthermore, the three BALB/c substrains exhibited similar patterns in their histopathological structure in DMBA+TPA-induced tumors. The expression levels of apoptotic proteins and tumor related proteins were constantly maintained in all three BALB/c substrains treated with DMBA+TPA. In addition, the responsiveness to cisplatin treatment was overall very similar in the three BALB/c substrains with DMBA+TPA-induced tumors. Taken together, these results indicate that genetic background of the three BALB/c substrains does not have a major effect on the DMBA+TPA-induced skin carcinogenesis and therapeutic responsiveness of cisplatin, except induction efficacy.

ACE2 and SARS-CoV-2 Expression in the Normal and COVID-19 Pancreas

SUMMARYDiabetes is associated with increased mortality from Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2). Given literature suggesting a potential association between SARS-CoV-2 infection and diabetes induction, we examined pancreatic expression of the key molecule for SARS-CoV-2 infection of cells, angiotensin-converting enzyme-2 (ACE2). Specifically, we analyzed five public scRNAseq pancreas datasets and performed fluorescence in situ hybridization, Western blotting, and immunolocalization for ACE2 with extensive reagent validation on normal human pancreatic tissues across the lifespan, as well as those from coronavirus disease 2019 (COVID-19) patients. These in silico and ex vivo analyses demonstrated pancreatic expression of ACE2 is prominent in pancreatic ductal epithelium and the microvasculature, with rare endocrine cell expression of this molecule. Pancreata from COVID-19 patients demonstrated multiple thrombotic lesions with SARS-CoV-2 nucleocapsid protein expression primarily limited to ducts. SARS-CoV-2 infection of pancreatic endocrine cells, via ACE2, appears an unlikely central pathogenic feature of COVID-19 as it relates to diabetes.

Effects of Insulin on Fibronectin Alterations in Sciatic Nerve of Diabetic Rats-A Brief Report

Objective: Alteration in the basement membrane proteins maybe associated with diabetic neuropathy. Fibronectin is one of the most important components of peripheral nerves basement membrane. In this study we investigated the effects of insulin administration on prevention of alteration in fibronectin contents of sciatic nerve in diabetic rats. Materials and Methods: Twenty-four wistar rats were divided into control, diabetic and diabetic with insulin treatment groups. Three months after diabetes induction, we measured blood glucose level, body weight and then expression of fibronectin in sciatic nerves of rats were evaluated by real time polymerase chain reaction (PCR) and immunohistochemical study. Results: Intensity of fibronectin immunoreactivity in the perineurium and endoneurium of sciatic nerves significantly increased in diabetic without treatment group compared to control group (P-value< 0.001). Conclusion: This finding suggested that diabetic neuropathy resulted in increased of fibronectin contents in sciatic nerves of rats.