USP28 Serves as a Key Suppressor of Mitochondrial Morphofunctional Defects and Cardiac Dysfunction in the Diabetic Heart.

BACKGROUND: The majority of people with diabetes are susceptible to cardiac dysfunction and heart failure, and conventional drug therapy cannot correct diabetic cardiomyopathy progression. Herein, we assessed the potential role and therapeutic value of USP28 (ubiquitin-specific protease 28) on the metabolic vulnerability of diabetic cardiomyopathy. METHODS: The type 2 diabetes mouse model was established using db/db leptin receptor-deficient mice and high-fat diet/streptozotocin-induced mice. Cardiac-specific knockout of USP28 in the db/db background mice was generated by crossbreeding db/m and Myh6-Cre+/USP28fl/fl mice. Recombinant adeno-associated virus serotype 9 carrying USP28 under cardiac troponin T promoter was injected into db/db mice. High glucose plus palmitic acid-incubated neonatal rat ventricular myocytes and human induced pluripotent stem cell-derived cardiomyocytes were used to imitate diabetic cardiomyopathy in vitro. The molecular mechanism was explored through RNA sequencing, immunoprecipitation and mass spectrometry analysis, protein pull-down, chromatin immunoprecipitation sequencing, and chromatin immunoprecipitation assay. RESULTS: Microarray profiling of the UPS (ubiquitin-proteasome system) on the basis of db/db mouse hearts and diabetic patients' hearts demonstrated that the diabetic ventricle presented a significant reduction in USP28 expression. Diabetic Myh6-Cre+/USP28fl/fl mice exhibited more severe progressive cardiac dysfunction, lipid accumulation, and mitochondrial disarrangement, compared with their controls. On the other hand, USP28 overexpression improved systolic and diastolic dysfunction and ameliorated cardiac hypertrophy and fibrosis in the diabetic heart. Adeno-associated virus serotype 9-USP28 diabetic mice also exhibited less lipid storage, reduced reactive oxygen species formation, and mitochondrial impairment in heart tissues than adeno-associated virus serotype 9-null diabetic mice. As a result, USP28 overexpression attenuated cardiac remodeling and dysfunction, lipid accumulation, and mitochondrial impairment in high-fat diet/streptozotocin-induced type 2 diabetes mice. These results were also confirmed in neonatal rat ventricular myocytes and human induced pluripotent stem cell-derived cardiomyocytes. RNA sequencing, immunoprecipitation and mass spectrometry analysis, chromatin immunoprecipitation assays, chromatin immunoprecipitation sequencing, and protein pull-down assay mechanistically revealed that USP28 directly interacted with PPARα (peroxisome proliferator-activated receptor α), deubiquitinating and stabilizing PPARα (Lys152) to promote Mfn2 (mitofusin 2) transcription, thereby impeding mitochondrial morphofunctional defects. However, such cardioprotective benefits of USP28 were largely abrogated in db/db mice with PPARα deletion and conditional loss-of-function of Mfn2. CONCLUSIONS: Our findings provide a USP28-modulated mitochondria homeostasis mechanism that involves the PPARα-Mfn2 axis in diabetic hearts, suggesting that USP28 activation or adeno-associated virus therapy targeting USP28 represents a potential therapeutic strategy for diabetic cardiomyopathy.

Protective effects of imeglimin on the development of atherosclerosis in ApoE KO mice treated with STZ.

BACKGROUND: Imeglimin is a new anti-diabetic drug which promotes insulin secretion from pancreatic ß-cells and reduces insulin resistance in insulin target tissues. However, there have been no reports examining the possible anti-atherosclerotic effects of imeglimin. In this study, we investigated the possible anti-atherosclerotic effects of imeglimin using atherosclerosis model ApoE KO mice treated with streptozotocin (STZ). METHODS: ApoE KO mice were divided into three groups: the first group was a normoglycemic group without injecting STZ (non-DM group, n = 10). In the second group, mice were injected with STZ and treated with 0.5% carboxymethyl cellulose (CMC) (control group, n = 12). In the third group, mice were injected with STZ and treated with imeglimin (200 mg/kg, twice daily oral gavage, n = 12). We observed the mice in the three groups from 10 to 18 weeks of age. Plaque formation in aortic arch and expression levels of various vascular factors in abdominal aorta were evaluated for each group. RESULTS: Imeglimin showed favorable effects on the development of plaque formation in the aortic arch in STZ-induced hyperglycemic ApoE KO mice which was independent of glycemic and lipid control. Migration and proliferation of vascular smooth muscle cells and infiltration of macrophage were observed in atherosclerotic lesions in STZ-induced hyperglycemic ApoE KO mice, however, which were markedly reduced by imeglimin treatment. In addition, imeglimin reduced oxidative stress, inflammation and inflammasome in hyperglycemic ApoE KO mice. Expression levels of macrophage makers were also significantly reduced by imeglimin treatment. CONCLUSIONS: Imeglimin exerts favorable effects on the development of plaque formation and progression of atherosclerosis.

Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker on oxidative stress and metabolism of elements in kidney of STZ-induced diabetic rats.

In diabetes, increased oxidative stress and impaired trace element metabolism play an important role in the pathogenesis of diabetic nephropathy. The objective of this research was to examine the outcomes of blocking the renin-angiotensin system, using either the angiotensin-converting enzyme inhibitor (ACEI), perindopril, or the angiotensin II type 1 (AT1) receptor blocker, irbesartan, on oxidative stress and trace element levels such as Zn, Mg, Cu, and Fe in the kidneys of diabetic rats that had been induced with streptozotocin. Thirty-two Wistar albino male rats were equally divided into four groups. The first group was used as a control. The second group of rats developed diabetes after receiving a single intraperitoneal dose of STZ. The third and fourth groups of rats had STZ-induced diabetes and received daily dosages of irbesartan (15 mg/kg b.w/day) and perindopril (6 mg/kg b.w/day) treatment, respectively. Biochemical analysis of the kidneys showed a distinct increase in oxidative stress, indicated by heightened levels of malondialdehyde (MDA) and decreased superoxide dismutase (SOD) activities, as well as reduced glutathione (GSH) levels in the kidneys of diabetic rats. In the kidneys of diabetic rats, the mean levels of Fe and Cu were found to be significantly higher than those of the control group. Additionally, the mean levels of Zn and Mg were significantly lower in the diabetic rats compared to the control rats. Both perindopril and irbesartan decreased significantly MDA content and increased SOD activities and GSH levels in the kidneys of rats with diabetes. The Zn and Mg concentrations in the kidneys of diabetic rats treated with perindopril and irbesartan were markedly higher than in untreated STZ-diabetic rats, while the Cu and Fe concentrations were significantly lower. The urinary excretion of rats treated with perindopril and irbesartan showed a pronounced increase in Cu levels, along with a significant reduction in Zn and Mg levels. Although diabetic rats demonstrated degenerative morphological alterations in their kidneys, both therapies also improved diabetes-induced histopathological modifications in the kidneys. Finally, the present results suggest that manipulating the levels of Zn, Mg, Cu, and Fe - either through ACE inhibition or by blocking AT1 receptors - could be advantageous in reducing lipid peroxidation and increasing antioxidant concentration in the kidneys of diabetic rats.

The efficacy of using metformin and/or quercetin for amelioration of gamma-irradiation induced tongue toxicity in diabetic rats.

BACKGROUND: Diabetes is a common disease that cancer patients may suffer from and may aggravate side effects of radiotherapy. This study aimed to detect whether metformin and/or quercetin will improve gamma-irradiation induced tongue toxicity in diabetic rats. METHODS: 35 male albino rats were divided into five groups; NOR no streptozotocin, no radiation and no treatment was given, DR rats were subjected to streptozotocin then gamma-irradiation, DRM rats were subjected to streptozotocin then gamma-irradiation then metformin, DRQ rats were subjected to streptozotocin then gamma-irradiation then quercetin, DRMQ rats were subjected to streptozotocin then gamma-irradiation then metformin and quercetin. Rats were euthanized 24 h after last treatment dose. Mean blood glucose level was recorded. Tongue specimens were stained with H&E and CD68. Histomorphometric analysis of length, diameter and taste buds of lingual papillae and epithelial, keratin and lamina propria thickness and CD68 positive cells were calculated. RESULTS: Blood glucose level of DRMQ was significantly lower than DR, DRM and DRQ, whereas higher than NOR. Metformin or quercetin partially restored tongue structure, papillae length and diameter and tongue layers thickness. The ameliorative effect was superior when metformin and quercetin were used together. Diabetes and irradiation significantly increased number of CD68 positive macrophages in submucosa and muscles. Metformin or quercetin significantly reduced number of lingual macrophages with more noticeable effect for quercetin. Treatment with metformin and quercetin significantly decreased number of macrophages. CONCLUSIONS: Combined use of metformin and quercetin might help mitigate the harmful effects of radiotherapy and diabetes on lingual tissues.

Ulinastatin ameliorated streptozotocin-induced diabetic nephropathy: Potential effects via modulating the components of gut-kidney axis and restoring mitochondrial homeostasis.

Growing evidence supports the role of the gut-kidney axis and persistent mitochondrial dysfunction in the pathogenesis of diabetic nephropathy (DN). Ulinastatin (UTI) has a potent anti-inflammatory effect, protecting the kidney and the gut barrier in sepsis, but its effect on DN has yet to be investigated. This study aimed to assess the potential mitigating effect of UTI on DN and investigate the possible involvement of gut-kidney axis and mitochondrial homeostasis in this effect. Forty male Wistar rats were divided equally into four groups: normal; UTI-treated control; untreated DN; and UTI-treated DN. At the end of the experiment, UTI ameliorated DN by modulating the gut-kidney axis as it improved serum and urinary creatinine, urine volume, creatinine clearance, blood urea nitrogen, urinary albumin, intestinal morphology including villus height, crypt depth, and number of goblet cells, with upregulating the expression of intestinal tight-junction protein claudin-1, and counteracting kidney changes as indicated by significantly decreasing glomerular tuft area and periglomerular and peritubular collagen deposition. In addition, it significantly reduced intestinal and renal nuclear factor kappa B (NF-κB), serum Complement 5a (C5a), renal monocyte chemoattractant protein-1 (MCP-1), renal intercellular adhesion molecule 1 (ICAM1), and renal signal transducer and activator of transcription 3 (STAT3), mitochondrial dynamin related protein 1 (Drp1), mitochondrial fission 1 protein (FIS1), mitochondrial reactive oxygen species (ROS), renal hydrogen peroxide (H2O2), and 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels. Furthermore, it significantly increased serum short chain fatty acids (SCFAs), and mitochondrial ATP levels and mitochondrial transmembrane potential. Moreover, there were significant correlations between measured markers of gut components of the gut-kidney axis and renal function tests in UTI-treated DN group. In conclusion, UTI has a promising therapeutic effect on DN by modulating the gut-kidney axis and improving renal mitochondrial dynamics and redox equilibrium.

Antioxidant effects of silver nanoparticles obtained by green synthesis from the aqueous extract of Eryngium carlinae on the brain mitochondria of streptozotocin-induced diabetic rats.

Diabetes mellitus is a metabolic disorder characterized by chronic hyperglycemia that affects practically all tissues and organs, being the brain one of most susceptible, due to overproduction of reactive oxygen species induced by diabetes. Eryngium carlinae is a plant used in traditional Mexican medicine to treat diabetes, which has already been experimentally shown have hypoglycemic, antioxidant and hypolipidemic properties. The green synthesis of nanoparticles is a technique that combines plant extracts with metallic nanoparticles, so that the nanoparticles reduce the absorption and distribution time of drugs or compounds, increasing their effectiveness. In this work, the antioxidant effects and mitochondrial function in the brain were evaluated, as well as the hypoglycemic and hypolipidemic effect in serum of both the aqueous extract of the aerial part of E. carlinae, as well as its combination with silver nanoparticles of green synthesis. Administration with both, extract and the combination significantly decreased the production of reactive oxygen species, lipid peroxidation, and restored the activity of superoxide dismutase 2, glutathione peroxidase, and electron transport chain complexes in brain, while that the extract-nanoparticle combination decreased blood glucose and triglyceride levels. The results obtained suggest that both treatments have oxidative activity and restore mitochondrial function in the brain of diabetic rats.

Impacts of trelagliptin and remogliflozin alone and in combination with Alpha Lipoic Acid on cardiac function in streptozotocin-induced diabetes mellitus in rats.

This study investigated the effects of trelagliptin and remogliflozin, alone and in combination with alpha lipoic acid (ALA), on cardiac biomarkers in diabetic cardiomyopathy (DCM). We aimed to assess the management of glucotoxicity consequences in streptozotocin-induced diabetic rats by measuring serum levels of pharmacologically active endogenous ligands. Forty-eight male rats were divided into different treatment groups, including negative control, positive control, and four experimental groups. After inducing diabetes, the rats were treated for 28 days, and serum levels of biomarkers associated with oxidative stress (malondialdehyde and thioredoxin-interacting protein), inflammation (nuclear factor NF-kappa-B p105 and lipoprotein-associated phospholipase A2), and myopathy (neprilysin and high selective cardiac troponin T) were measured. Immunohistochemical analysis of heart cells was also performed. The results showed that inducing hyperglycemia increased serum glucose levels and biomarkers associated with DCM. However, all treatment groups exhibited a significant decrease in these biomarkers and an increase in insulin levels compared to the diabetic control group. The groups receiving combination therapy with ALA showed greater improvements in cardiac biomarkers compared to the individual treatments. The immunohistochemical analysis supported these findings by demonstrating a reduction in the percentage area of cathepsin B, a protein involved in DCM pathophysiology. In conclusion, supplementing the base treatments with ALA showed promise in enhancing cardiac biomarkers associated with DCM. The combination of trelagliptin, remogliflozin, and ALA may have additional clinical value in managing DCM by targeting oxidative stress, inflammation, and glucotoxicity. However, further research is needed to validate these findings and explore their potential clinical applications.

Laboratory and clinical findings in mouse models of diabetic nephropathy induced with streptozotocin.

BACKGROUND: Diabetic nephropathy (DN) represents a microvascular complication of diabetes mellitus (DM). Despite the increasing incidence and prevalence of DN, conservative therapy only reduces risk factors and hemodialysis. This research aimed at finding DN animal model that can be tried to be given an alternative treatment. DN was assessed by evaluating body weight, blood glucose, proteinuria, and kidney histopathology. METHODS: Wistar novergicus male rats were induced with 75 mg of streptozotocin per kg BW to obtain a diabetic nephropathy model. The 18 rats were divided into 2 groups consisting of 9 rats in the negative group (G0) and 9 rats in the positive group (G1). Indicators of body weight, blood glucose levels, urine protein and kidney histopathology determine the incidents of DN animal models. RESULT: Rats induced using 75 mg of streptozotocin per kg body weight (BW) indicated weight loss, increased blood glucose, urine protein levels and histopathological features of DN. CONCLUSION: Seventy-five mg of streptozotocin per kg BW can induce a diabetic nephropathy animal model in Wistar norvegicus rats.

Oxidative stress in liver of streptozotocin-induced diabetic mice fed a high-fat diet: A treatment role of Artemisia annua L.

Objective. The aim of this study was the investigation of a treatment role of Artemisia annua L. (AA) on liver dysfunction and oxidative stress in high-fat diet/streptozotocin-induced diabetic (HFD/STZ) mice. Methods. Sixty mice were divided into 12 groups including control, untreated diabetic, and treated diabetic ones with metformin (250 mg/kg), and doses of 100, 200, and 400 mg/kg of water (hot and cold) and alcoholic (methanol) extracts of AA. Type 2 diabetes mellitus (T2DM) was induced in mice by high-fat diet for 8 weeks and STZ injection in experimental animals. After treatment with doses of 100, 200 or 400 mg/kg of AA extracts in HFD/STZ diabetic mice for 4 weeks, oxidative stress markers such as malondialdehyde (MDA), glutathione (GSH), and free radicals (ROS) were determined in the liver tissue in all groups. Results. Diabetic mice treated with metformin and AA extracts showed a significant decrease in ROS and MDA concentrations and a notable increase in GSH level in the liver. Effectiveness of higher doses of AA extracts (200 and 400 mg/kg), especially in hot-water and alcoholic ones, were similar to and/or even more effective than metformin. Conclusion. Therapeutic effects of AA on liver dysfunction showed that antioxidant activity of hot-water and alcoholic AA extracts were similar or higher than of metformin.

Metabolic Alterations in Streptozotocin-nicotinamide-induced Diabetic Rats Treated with Muntingia calabura Extract via 1H-NMR-based Metabolomics.

Diabetes mellitus (DM) is a metabolic endocrine disorder caused by decreased insulin concentration or poor insulin response. Muntingia calabura (MC) has been used traditionally to reduce blood glucose levels. This study aims to support the traditional claim of MC as a functional food and blood-glucose-lowering regimen. The antidiabetic potential of MC is tested on a streptozotocin-nicotinamide (STZ-NA)-induced diabetic rat model by using the 1H-NMR-based metabolomic approach. Serum biochemical analyses reveal that treatment with 250 mg/kg body weight (bw) standardized freeze-dried (FD) 50% ethanolic MC extract (MCE 250) shows favorable serum creatinine (37.77 ± 3.53 µM), urea (5.98 ± 0.84 mM) and glucose (7.36 ± 0.57 mM) lowering capacity, which was comparable to the standard drug, metformin. The clear separation between diabetic control (DC) and normal group in principal component analysis indicates the successful induction of diabetes in the STZ-NA-induced type 2 diabetic rat model. A total of nine biomarkers, including allantoin, glucose, methylnicotinamide, lactate, hippurate, creatine, dimethylamine, citrate and pyruvate are identified in rats' urinary profile, discriminating DC and normal groups through orthogonal partial least squares-discriminant analysis. Induction of diabetes by STZ-NA is due to alteration in the tricarboxylic acid (TCA) cycle, gluconeogenesis pathway, pyruvate metabolism and nicotinate and nicotinamide metabolism. Oral treatment with MCE 250 in STZ-NA-induced diabetic rats shows improvement in the altered carbohydrate metabolism, cofactor and vitamin metabolic pathway, as well as purine and homocysteine metabolism.

The Hypoglycemic and Hypolipidemic Effects of Polyphenol-Rich Strawberry Juice on Diabetic Rats.

Obesity and diabetes are some of the most important modern health problems requiring simple preventative or palliative measures using dietary means. This study investigated the impact of strawberry juice on diabetic rats. Diabetes was induced in rats using a single intraperitoneal injection of 50 mg/kg streptozotocin (STZ). Fifty male rats were divided into five groups: normal control (NC), strawberry juice only (S), diabetic control (DC), and two diabetic groups treated with strawberry juice (DC + S) or metformin (DC + met). Rats were administered a single dose of both strawberry juice and oral metformin, and biochemical and histological analyses were conducted. The experiment was conducted in compliance with the Ethics Committee's regulations for the care and utilization of animals, microorganisms, and living cell cultures in education and scientific research at the Faculty of Agriculture, Minia University (MU/FA/006/12/22). Treatment of diabetic rats with strawberry juice led to a significant decrease in blood glucose. Insulin levels were also significantly increased, while lipid profiles were lowered in the diabetic rats treated with strawberry juice. Carbohydrate metabolism enzymes and antioxidant enzyme activities in the treated rats were restored to normal levels, and the levels of lipid peroxidation and proinflammatory cytokines were notably reduced. The microstructure of pancreatic and liver cells in diabetic rats was also improved with strawberry juice treatment. In addition, HPLC analysis revealed that strawberry juice was rich in flavonoids and phenolic compounds and exhibited potent antioxidant activity. These findings suggest that strawberry juice has considerable hypoglycemic and hypolipidemic effects on rats with diabetes which may be used in human after further investigations.

Evaluation of Sida cordifolia and Sida rhombifolia extracts in a rat model of streptozotocin-induced diabetic nephropathy.

BACKGROUND: Sida cordifolia and Sida rhombifolia are regarded as useful herbs as they have been shown to be effective, inexpensive and harmless in the prevention of diabetes, and are recognized as valuable therapeutic substances. OBJECTIVES: The purpose of this study was to assess the effect of S. cordifolia and S. rhombifolia in the treatment of diabetic nephropathy using a rat model. MATERIAL AND METHODS: Extracts of S. cordifolia and S. rhombifolia were obtained using the Soxhlet method. The hydroalcoholic extract solvent was used in the following proportions: 70:30, 50:50 and 80:20. The 80:20 hydroalcoholic extract was observed to be the most potent. The inhibitory effects of the extract were determined using the α-amylase assay. The most potent extract also underwent total flavonoid, phenolic and free radical scavenging tests, and was incorporated into an animal study. Diabetes was induced in rats by administering nicotinamide (NAD; 230 mg/kg) and streptozotocin (STZ; 65 mg/kg) intraperitoneally. In addition to a standard control of pioglitazone, the rats received extract dosages of 100 mg/kg/day or 200 mg/kg/day. Body weight, blood glucose, glycated hemoglobin (HbA1c), blood urea nitrogen (BUN), serum albumin, serum creatinine, homeostatic model assessment of insulin resistance (HOMA-IR), and oral glucose tolerance were assessed at various time points. The animals also underwent histopathological examination to observe alterations induced by the treatment. RESULTS: Sida cordifolia was the most successful in lowering blood glucose and HbA1c levels. Renal function indices and antioxidant enzyme levels were regained in a dose-dependent manner. Furthermore, S. cordifolia (200 mg/kg/day) extract, similar to pioglitazone, inhibited the production of advanced glycation byproducts by the kidney. CONCLUSIONS: The effects of various S. cordifolia and S. rhombifolia extracts on rats with diabetic nephropathy were observed. Sida cordifolia may be further explored for the treatment of diabetic nephropathy and, due to its diverse nature, may be utilized for the treatment of a wide range of diseases, as it provided more significant findings.

Streptozotocin, 1982-2022: Forty Years from the FDA's Approval to Treat Pancreatic Neuroendocrine Tumors.

In May 1982, the US Food and Drug Administration (FDA) approved the use of streptozotocin to treat pancreatic neuroendocrine tumors (panNETs). Thus, this year marks 40 years since that landmark date. This review of streptozotocin to treat panNETs is intended to commemorate this anniversary. A historical perspective of the chemical structure, pharmacokinetics, and mechanism of action of streptozotocin is followed by data from prospective and retrospective clinical studies. The last section of the review addresses the latest aspects and takes note of the prospects that lie ahead on the future horizon of the use of streptozotocin to treat panNETs, including ongoing clinical trials.

Localization Defines Streptozotocin/5-FU Response in Primary Pancreatic Neuroendocrine Tumours.

INTRODUCTION: Incidence of pancreatic neuroendocrine tumours (pNETs) is on the rise. The only curative treatment is surgical resection in localized or oligo-metastatic disease. However, patients may present with locally advanced or unresectable primary tumours. So far, no conversion therapy to achieve resectability has been established, which is partly due to lack of data on primary tumour response to therapies. Here, we specifically evaluate the primary tumour response to streptozocin/5-FU in a large cohort of metastatic pNET patients. METHODS: Five ENETS centres in Germany contributed 84 patients to the study cohort for retrospective analysis. RESULTS: Overall response rate (ORR) in primary tumours was 34% and disease control rate (DCR) 88%. ORR was different in metastases at 44% and DCR at 70%. Partial remission in primary tumours was more frequent among those located in pancreatic tail than that in pancreatic head (49% vs. 14%, p = 0.03). Correspondingly, metastases from tumours originating from pancreatic tail responded more frequently than metastases originating from pancreatic head (88.5% vs. 41.7%, p = 0.005). The median PFS of the primary tumours was longer than that in metastases (31 months vs. 16 months; p = 0.04). Considerable downsizing of the primary tumour was rare and occurred primarily in tumours located in the pancreatic tail. CONCLUSION: STZ/5-FU can achieve disease stabilization in a high proportion of metastatic pNET patients. In the majority of cases however it does not induce substantial downsizing of the primary tumour, thus possibly limiting its potential as conversion chemotherapy. Furthermore, the difference in response rate observed between different primary tumour locations warrants further exploration.

Disbalance of the Duodenal Epithelial Cell Turnover and Apoptosis Accompanies Insensitivity of Intestinal Redox Homeostasis to Inhibition of the Brain Glucose-Dependent Insulinotropic Polypeptide Receptors in a Rat Model of Sporadic Alzheimer's Disease.

INTRODUCTION: Gastrointestinal dyshomeostasis is investigated in the context of metabolic dysfunction, systemic, and neuroinflammation in Alzheimer's disease. Dysfunctional gastrointestinal redox homeostasis and the brain-gut incretin axis have been reported in the rat model of insulin-resistant brain state-driven neurodegeneration induced by intracerebroventricular streptozotocin (STZ-icv). We aimed to assess whether (i) the structural epithelial changes accompany duodenal oxidative stress; (ii) the brain glucose-dependent insulinotropic polypeptide receptor (GIP-R) regulates redox homeostasis of the duodenum; and (iii) the STZ-icv brain-gut axis is resistant to pharmacological inhibition of the brain GIP-R. METHODS: GIP-R inhibitor [Pro3]-GIP (85 µg/kg) was administered intracerebroventricularly to the control and the STZ-icv rats 1 month after model induction. Thiobarbituric acid reactive substances (TBARSs) were measured in the plasma and duodenum, and the sections were analyzed morphometrically. Caspase-3 expression and activation were assessed by Western blot and multiplex fluorescent signal amplification. RESULTS: Intracerebroventricular [Pro3]-GIP decreased plasma TBARSs in the control and STZ-icv animals and increased duodenal TBARSs in the controls. In the controls, inhibition of brain GIP-R affected duodenal epithelial cells, but not villus structure, while all morphometric parameters were altered in the STZ-icv-treated animals. Morphometric changes in the STZ-icv animals were accompanied by reduced levels of caspase-3. Suppression of brain GIP-R inhibited duodenal caspase-3 activation. CONCLUSION: Brain GIP-R seems to be involved in the regulation of duodenal redox homeostasis and epithelial cell turnover. Resistance of the brain-gut GIP axis and morphological changes indicative of abnormal epithelial cell turnover accompany duodenal oxidative stress in the STZ-icv rats.

Beneficial metabolic effects of recurrent periods of beta-cell rest and stimulation using stable neuropeptide Y1 and glucagon-like peptide-1 receptor agonists.

AIM: To examine whether sequential administration of (d-Arg35 )-sea lamprey peptide tyrosine tyrosine (1-36) (SL-PYY) and the glucagon-like peptide-1 (GLP-1) mimetic, liraglutide, has beneficial effects in diabetes. METHODS: SL-PYY is an enzymatically stable neuropeptide Y1 receptor (NPY1R) agonist known to induce pancreatic beta-cell rest and improve overall beta-cell health. We employed SL-PYY and liraglutide to induce appropriate recurrent periods of beta-cell rest and stimulation, to assess therapeutic benefits in high fat fed (HFF) mice with streptozotocin (STZ)-induced insulin deficiency, namely HFF-STZ mice. RESULTS: Previous studies confirm that, at a dose of 0.25 nmol/kg, liraglutide exerts bioactivity over an 8-12 hour period in mice. Initial pharmacokinetic analysis revealed that 75 nmol/kg SL-PYY yielded a similar plasma drug time profile. When SL-PYY (75 nmol/kg) and liraglutide (0.25 nmol/kg) were administered sequentially at 08:00 AM and 08:00 PM, respectively, to HFF-STZ mice for 28 days, reductions in energy intake, body weight, circulating glucose, insulin and glucagon were noted. Similarly positive, but slightly less striking, effects were also apparent with twice-daily liraglutide-only therapy. The sequential SL-PYY and liraglutide treatment also improved insulin sensitivity and glucose-induced insulin secretory responses, which was not apparent with liraglutide treatment, although benefits on glucose tolerance were mild. Interestingly, combined therapy also elevated pancreatic insulin, decreased pancreatic glucagon and enhanced the plasma insulin/glucagon ratio compared with liraglutide alone. This was not associated with an enhancement of beneficial changes in islet cell areas, proliferation or apoptosis compared with liraglutide alone, but the numbers of centrally stained glucagon-positive islet cells were reduced by sequential combination therapy. CONCLUSION: These data show that NPY1R-induced intervals of beta-cell rest, combined with GLP-1R-stimulated periods of beta-cell stimulation, should be further evaluated as an effective treatment option for obesity-driven forms of diabetes.

Spinal cannabinoid CB1 or CB2 receptors activation attenuates mechanical allodynia in streptozotocin-induced diabetic rats.

Diabetes is a chronic disease associated with a high number of complications such as peripheral neuropathy, which causes sensorial disturbances and may lead to the development of diabetic neuropathic pain (DNP). The current treatment for DNP is just palliative and the drugs may cause severe adverse effects, leading to discontinuation of treatment. Thus, new therapeutic targets need to be urgently investigated. Studies have shown that cannabinoids have promising effects in the treatment of several pathological conditions, including chronic pain. Thus, we aimed to investigate the acute effect of the intrathecal injection of CB1 or CB2 cannabinoid receptor agonists N-(2-chloroethyl)-5Z, 8Z, 11Z, 14Z-eicosatetraenamide (ACEA) or JWH 133, respectively (10, 30 or 100 µg/rat) on the mechanical allodynia associated with experimental diabetes induced by streptozotocin (60 mg/kg; intraperitoneal) in rats. Cannabinoid receptor antagonists CB1 AM251 or CB2 AM630 (1 mg/kg) were given before treatment with respective agonists to confirm the involvement of cannabinoid CB1 or CB2 receptors. Rats with diabetes exhibited a significant reduction on the paw mechanical threshold 2 weeks after diabetes induction, having the maximum effect observed 4 weeks after the streptozotocin injection. This mechanical allodynia was significantly improved by intrathecal treatment with ACEA or JWH 133 (only at the higher dose of 100 µg). Pre-treatment with AM251 or AM630 significantly reverted the anti-allodynic effect of the ACEA or JWH 133, respectively. Considering the clinical challenge that the treatment of DPN represents, this study showed for the first time, that the intrathecal cannabinoid receptors agonists may represent an alternative for the treatment of DNP.

Bacillus sp. DU-106 ameliorates type 2 diabetes by modulating gut microbiota in high-fat-fed and streptozotocin-induced mice.

AIMS: Type 2 diabetes (T2D) is a chronic disease that manifests as endocrine and metabolic disorders that seriously threatening public health. This study aimed to investigate the effects of Bacillus sp. DU-106 on anti-diabetic effects and gut microbiota in C57BL/6J mice fed a high-fat diet and streptozotocin-induced T2D. METHODS AND RESULTS: Bacillus sp. DU-106 was administered to model mice for eight consecutive weeks. Oral administration of Bacillus sp. DU-106 decreased food and water intake and alleviated body weight loss. Moreover, Bacillus sp. DU-106 imparted several health benefits to mice, including balanced blood glucose, alleviation of insulin resistance in T2D mice and an improvement in lipid metabolism. Furthermore, Bacillus sp. DU-106 protected against liver and pancreatic impairment. Additionally, Bacillus sp. DU-106 treatment reshaped intestinal flora by enhancing gut microbial diversity and enriching the abundance of certain functional bacteria. CONCLUSION: Collectively, these findings suggest that Bacillus sp. DU-106 can ameliorate T2D by regulating the gut microbiota. SIGNIFICANCE AND IMPACT OF STUDY: Therefore, a novel probiotic, Bacillus sp. DU-106 may be a promising therapeutic agent for improving and alleviating T2D in mice.

Biochanin-A has antidiabetic, antihyperlipidemic, antioxidant, and protective effects on diabetic nephropathy via suppression of TGF-ß1 and PAR-2 genes expression in kidney tissues of STZ-induced diabetic rats.

One of the major complications of diabetes is diabetic nephropathy, and often many patients suffer from diabetic nephropathy. That is why it is important to find the mechanisms that cause nephropathy and its treatment. This study was designed to examine the antidiabetic effects of biochanin A (BCA) and evaluate its effects on oxidative stress markers and the expression of transforming growth factor-ß1 (TGF-ß1) and protease-activated receptors-2 (PAR-2) genes in the kidney of type 1 diabetic rats. After induction of diabetes using streptozotocin (STZ), 55 mg/kg bw dose, rats were randomly divided into four groups with six rats in each group as follows: normal group: normal control receiving normal saline and a single dose of citrate buffer daily; diabetic control group: diabetic control receiving 0.5% dimethyl sulfoxide daily; diabetic+BCA (10 mg/kg) group: diabetic rats receiving biochanin A at a dose of 10 mg/kg bw daily; diabetic+BCA (15 mg/kg) group: diabetic rats receiving biochanin A at a dose of 15 mg/kg bw daily. TGF-ß1 and PAR-2 gene expression was assessed by real-time. Spectrophotometric methods were used to measure biochemical factors: fast blood glucose (FBG), urea, creatinine, albumin, lipids profiles malondialdehyde (MDA), and superoxide dismutase (SOD). The course of treatment in this study was 42 days. The results showed that in the diabetic control group, FBG, serum urea, creatinine, expression of TGF-ß1 and PAR-2 genes, and the levels of MDA in kidney tissue significantly increased and SOD activity in kidney tissue and serum albumin significantly decreased compared to the normal group (p < 0.001). The results showed that administration of biochanin A (10 and 15 mg/kg) after 42 days significantly reduced the expression of TGF-ß1 and PAR-2 genes and FBG, urea, creatinine in serum compared to the diabetic control group (p < 0.001), also significantly increased serum albumin compared to the diabetic control group (p < 0.001). The level of MDA and SOD activity in the tissues of diabetic rats that used biochanin A (10 and 15 mg/kg) was significantly reduced and increased, respectively, compared to the diabetic control group (p < 0.001). Also, the result showed that in the diabetic control group lipids profiles significantly is disturbed compared to the normal group (p < 0.001), the results also showed that biochanin A (10 and 15 mg/kg) administration could significantly improved the lipids profile compared to the control diabetic group (p < 0.001). It is noteworthy that it was found that the beneficial effects of the biochanin A were dose dependent. In conclusion, administration of biochanin A for 42 days has beneficial effect and improves diabetes and nephropathy in diabetic rats. So probably biochanin A can be used as an adjunct therapy in the treatment of diabetes.

Red wine but not alcohol consumption improves cardiovascular function and oxidative stress of the hypertensive-SHR and diabetic-STZ rats.

AIMS: This raised the issue of whether in vivo long-term red wine treatment can act as a modulator of these targets. MAIN METHODS: We monitored SBP, glucose tolerance, oxidative stress, and cardiovascular function. Aortic and atrial tissues from normotensive-WKY, hypertensive-SHR, and diabetic-STZ animals, chronically exposed to red wine (3.715 ml/kg/v.o/day) or alcohol (12%) for 21-days, were used to measure contractile/relaxation responses by force transducers. Key findings: red wine, but not alcohol, prevented the increase of SBP and hyperglycemic peak. Additionally, was observed prevention of oxidative stress metabolites formation and an improvement in ROS scavenging antioxidant capacity of SHR. We also revealed that red wine intake enhances the endothelium-dependent relaxation, decreases the hypercontractile mediated by angiotensin-II in the aorta, and via ß1-adrenoceptors in the atrium. SIGNIFICANCE: The long-term consumption of red wine can improve oxidative stress and the functionality of angiotensin-II and ß1-adrenoceptors, inspiring new pharmacologic and dietetic therapeutic approaches for the treatment of hypertension and diabetes.Abbreviation Acronyms and/or abbreviations: [Ca2+]cyt = Cytosolic Ca2+ Concentration; ACh = Acetylcholine; ANG II = Angiotensin II; AT1 = ANG II type 1 receptor; AUC = Area Under the Curve; Ca2+ = Calcium; Endo + = Endothelium Intact; Fen = Phenylephrine (1 µM); GTT = Glucose Tolerance Test; ISO = Isoprenaline (isoproterenol); KHN = Krebs-Henseleit Nutrient; LA = Left Atria; LH = Lipid Hydroperoxide; NO = Nitric Oxide; RA = Right Atria; RAS = Renin-Angiotensin System; ROS = Reactive Oxygen Species; SBP = Systolic Blood Pressure; SHR = Spontaneously Hypertensive Rats; STZ = Streptozotocin; WKY = Normotensive Wistar Kyoto Rats.