ANGPT2/CAV1 regulates albumin transcytosis of glomerular endothelial cells under high glucose exposure and is impaired by losartan / ANGPT2/CAV1 regula la transcitosis de la albúmina de las células endoteliales glomerulares bajo exposición a hiperglucemia, alterándose con la intervención de losartan

Background Microalbuminuria is a common clinical symptom that manifests in the early stages of diabetic kidney disease (DKD) and is also the main feature of glomerular endothelial cells (GECs) injury. There is increasing evidence that the transcytosis of albumin across GECs is closely related to the formation of albuminuria. Our previous studies have shown that angiopoietin 2 (ANGPT2) can inhibit albumin transcytosis across renal tubular epithelial cells by activating caveolin 1 (CAV1) phosphorylation during high glucose (HG) exposure. The role of ANGPT2 in albumin transcytosis across GECs remains unclear. Losartan significantly reduces albuminuria, but the mechanism has not been clarified. Methods We established an in vitro albumin transcytosis model to investigate the change in albumin transcytosis across human renal glomerular endothelial cells (hrGECs) under normal glucose (NG), high glucose (HG) and losartan intervention. We knocked down ANGPT2 and CAV1 to evaluate their roles in albumin transcytosis across hrGECs and verified the relationship between them. In vivo, DKD mouse models were established and treated with different doses of losartan. Immunohistochemistry and Western blot were used to detect the expression of ANGPT2 and CAV1. Results In vitro, the transcytosis of albumin across hrGECs was significantly increased under high glucose stimulation, and losartan inhibited this process. The expression of ANGPT2 and CAV1 were both increased in hrGECs under HG conditions and losartan intervention reduced the expression of them. Moreover, ANGPT2 downregulation reduced albumin transcytosis in hrGECs by regulating CAV1 expression. In vivo, the expression of ANGPT2 and CAV1 in the glomerulus was both increased significantly in DKD mice. Compared with DKD mice, losartan treatment reduced albuminuria and decreased the expression of ANGPT2 and CAV1 in a dose-dependent manner (AU)

Antecedentes La microalbuminuria es un síntoma clínico común que se manifiesta en las fases tempranas de la enfermedad renal diabética (ERD), y también es característica del daño de las células endoteliales glomerulares (GEC). Existe evidencia creciente en cuanto a que la transcitosis de la albúmina a través de las GEC está estrechamente relacionada con la formación de albuminuria. Nuestros estudios previos reflejaron que angiopoyetina 2 (ANGPT2) puede inhibir la transcitosis de la albúmina a través de las células epiteliales tubulares renales activando la fosforilación de caveolina 1 (CAV1) durante la exposición a hiperglucemia (HG). El rol de ANGPT2 en la transcitosis de la albúmina a través de las GEC resulta incierto. Losartan reduce considerablemente la albuminuria, aunque no se ha esclarecido el mecanismo. Métodos Establecimos un modelo in vitro de transcitosis de la albúmina para investigar el cambio de dicho mecanismo a través de las células endoteliales glomerulares renales humanas (hrGEC) en condiciones de glucosa normal (GN), hiperglucemia (HG) e intervención de losartan. Realizamos breakdown de ANGPT2 y CAV1 para evaluar sus roles en la transcitosis de la albúmina a través de las hrGEC, y verificamos la relación entre ellas. Se establecieron modelos in vivo de ratones con ERD, tratados con diferentes dosis de losartan. Se utilizaron pruebas de inmunohistoquímica e inmunotransferencia para detectar la expresión de ANGPT2 y CAV1. Resultados In vitro, la transcitosis de la albúmina a través de hrGEC se incrementó considerablemente en condiciones de estimulación de la hiperglucemia, inhibiendo losartan este proceso. La expresión de ANGPT2 y CAV1 se incrementó en las hrGEC en condiciones de HG, reduciendo la intervención de losartan la expresión de ambas (AU)

RNF20/RNF40 ameliorates streptozotocin-induced type 1 diabetes by activating vitamin D receptors in vivo

Background: Type 1 diabetes is one of the chronic autoimmune diseases. Its features include the immune-triggered pancreatic beta-cells destruction. Ubiquitin ligases RNF20 and RNF40 have been discovered to participate into beta cells gene expression, insulin secretion, and expression of vitamin D receptors (VDRs). However, no reports about the role of RNF20/RNF40 in type 1 diabetes are known till now. The aim of this study was to clarify the role of RNF20/RNF40 in type 1 diabetes and explore the mechanism. Methods: In this study, streptozotocin (STZ)-induced mice type 1 diabetes model was used. The protein expressions of genes were examined through Western blot analysis. Fasting blood glucose was detected through glucose meter. The plasma insulin was tested through the commercial kit. Hematoxylin and eosin staining was utilized to observe pathological changes of pancreatic tissues. Immunofluorescence assay was performed to evaluate the level of insulin. The levels of pro-inflammatory cytokines in serum were assessed by enzyme-linked-immunosorbent serologic assay. The cell apoptosis was measured through terminal deoxynucleotidyl transferase dUTP nick end labelling assay. Results: STZ was used to stimulate mice model for type 1 diabetes. At first, both RNF20 and RNF40 expressions were down-regulated in STZ-mediated type 1 diabetes. Additionally, RNF20/RNF40 improved hyperglycemia in STZ-stimulated mice. Moreover, RNF20/RNF40 relieved pancreatic tissue injury in STZ-induced mice. Further experiments found that RNF20/RNF40 rescued the strengthened inflammation mediated by STZ treatment. The cell apoptosis was enhanced in the pancreatic tissues of STZ-triggered mice, but this effect was weakened by overexpression of RNF20/RNF40 (AU)

Anti-diabetic effects of Inonotus obliquus extract in high fat diet combined streptozotocin-induced type 2 diabetic mice / Efectos antidiabéticos del extracto de Inonotus obliquus en ratones diabéticos tipo 2 inducidos por estreptozotocina combinada con una dieta rica en grasas

Introduction: type 2 diabetes (T2DM) is a complex disease affected by lifestyle and genetic factors. Although the drugs currently used to treat T2DM have certain curative effects, they still have some adverse side effects. Therefore, it is urgent to find new effective drugs with few side effects to cure T2DM. Objective: to study the role of Inonotus obliquus (IO) in diabetic model mice. Methods: we used high-fat diet (HFD) combined with streptozocin (STZ) to establish a diabetic mouse model. Mice were divided into non-high-fat diet group (ND), diabetes model group (HFD + STZ) and IO-treated diabetes model group (IO). The mice in the IO group were orally treated with IO (150 mg/kg) at 10 ml/kg for five weeks. Body weight, glucose level, food intake and water consumption, glucose tolerance and insulin tolerance were evaluated in all mice. The pathological sections of liver, kidney and pancreas were observed by hematoxylin-eosin staining. Results: after IO administration, the blood glucose level, water consumption, low-density lipoprotein (LDL) and triacylglycerol (TG) levels of mice decreased. Compared with the HFD + STZ group, the number of normal islet iiiiiiii cells increased and focal necrosis of the liver was significantly reduced in the IO administration group. Conclusions: IO reduced the levels of blood glucose, restored body weight, and enhanced insulin sensitivity along with insulin tolerance and glucose tolerance in diabetic mice. Additionally, IO also reversed HFD and STZ-induced organ injury. (AU)

Introducción: la diabetes mellitus tipo 2 (T2DM) es una enfermedad compleja influenciada por el estilo de vida y los factores genéticos. En la actualidad, aunque los medicamentos para la diabetes tipo 2 tienen cierto efecto curativo, todavía tienen algunos efectos secundarios. Por lo tanto, es urgente encontrar nuevos medicamentos para la diabetes tipo 2 que tengan un buen efecto curativo y menos efectos secundarios. Objetivo: estudiar el papel del Inonotus obliquus (IO) en ratones diabéticos. Métodos: se estableció un modelo de ratón diabético con dieta de alto contenido en grasas (HFD) y estreptozocina (STZ). Los ratones se dividieron en el grupo de dieta no alta en grasas (ND), el grupo modelo de diabetes mellitus (HFD + STZ) y el grupo modelo de diabetes mellitus tratado con IO. Los ratones del grupo IO recibieron 10 ml/kg de IO (150 mg/kg) durante cinco semanas. Se observaron el peso corporal, el nivel de azúcar en sangre, la ingesta de alimentos, la ingesta de agua potable, la tolerancia a la glucosa y la tolerancia a la insulina de los ratones de cada grupo, y se estudiaron muestras de biopsias hepáticas, renales y pancreáticas mediante tinción de hematoxilina eosina. Resultados: los niveles de glucosa en sangre, el consumo de agua, la lipoproteína de baja densidad (LDL) y los triglicéridos (TG) disminuyeron después de la administración de IO. En comparación con el grupo HFD+STZ, el número de células β pancreáticas normales y la necrosis focal hepática disminuyeron significativamente en el grupo IO. Conclusiones: el IO redujo el nivel de glucosa en sangre, ayudó a recuperar el peso corporal y mejorar la sensibilidad a la insulina, la tolerancia a la insulina y la tolerancia a la glucosa en ratones diabéticos. Además, el IO revirtió el daño orgánico inducido por HFD y STZ. (AU)

Trimethylamine N-oxide facilitates the progression of atrial fibrillation in rats with type 2 diabetes by aggravating cardiac inflammation and connexin remodeling

Diabetes is an independent risk factor for atrial fibrillation (AF). This study aimed to elucidate the pathophysiology of diabetes-related AF from the perspective of the gut microbial metabolite trimethylamine N-oxide (TMAO). In the present study, male rats received either a normal diet to serve as the control group or a high-fat diet/streptozotocin to induce type 2 diabetes mellitus. Then, diabetic rats were divided into two groups based on the presence or absence of 3,3-dimethyl-1-butanol (DMB, a specific TMAO inhibitor) in drinking water: the diabetic cardiomyopathy (DCM) group and the DCM + DMB group. Eight weeks later, compared with control rats, rats in the DCM group exhibited gut microbiota dysbiosis and systemic TMAO elevation. The inflammatory cytokines IL-1β, IL-6, and TNF-α were markedly increased in the atria of rats in the DCM group. Downregulated expression of connexin 40 and lateralized distribution of connexin 43 were also observed in the atria of DCM rats. AF inducibility was significantly higher in DCM rats than in control rats. Furthermore, DMB treatment effectively ameliorated atrial inflammation and connexin remodeling while markedly reducing plasma TMAO levels. DMB treatment also decreased the vulnerability of diabetic rats to AF. In conclusion, TMAO might promote atrial inflammation and connexin remodeling in the development of diabetes, which may play a key role in mediating diabetes-related AF. (AU)

Exendin-4 may improve type 2 diabetes by modulating the epigenetic modifications of pancreatic histone H3 in STZ-induced diabetic C57BL/6 J mice

Type 2 diabetes (T2D) is a complicated systemic disease that might be improved by exendin-4, although the epigenetic role remains unclear. In the current study, C57BL/6 J mice were used to generate a T2D model, followed by treatment with exendin-4 (10 μg/kg). Histone H3K9 and H3K23 acetylation, H3K4 mono-methylation, and H3K9 di-methylation were explored by western blot analysis of pancreatic histone extracts. Real-time polymerase chain reaction (PCR) was used to examine the expression levels of pancreatic beta cell development-related genes, and chromatin immunoprecipitation (ChIP) was applied to analyze H3 and H3K9 acetylation, H3K4 mono-methylation, and H3K9 di-methylation in the promoter region of the pancreatic and duodenal homeobox 1 (Pdx1) gene. The results showed that total H3K9 di-methylation and H3K9 and H3K23 acetylation increased in pancreatic tissues of diabetic mice, whereas H3K4 mono-methylation was reduced. All of these changes could be abrogated by treatment with exendin-4. Our data indicated that T2D progression might be improved by exendin-4 treatment through the reversal of global pancreatic histone H3K9 and H3K23 acetylation, H3K4 mono-methylation, and H3K9 di-methylation. A better understanding of these epigenetic alterations may, therefore, lead to novel therapeutic strategies for T2D. (AU)

Evaluación del efecto hipoglucemiante de una fracción peptídica de las semillas de chía (Salvia hispanica L) en ratas macho Wistar inducidas con aloxano / Evaluation of the hypoglycemic effect of a peptide fraction of chia seeds (Salvia hispánica L) in male Wistar rats induced with alloxan

Introducción: se han realizado investigaciones sobre la diabetes con péptidos de diferentes fuentes alimentarias en animales experimentales para aplicarse después en los seres humanos. Objetivo: la finalidad de este trabajo fue evaluar en ratas el efecto hipoglucemiante de una fracción peptídica de chía obtenida por hidrólisis enzimática. Materiales y métodos: de la harina de chía se obtuvo una fracción rica en proteína que fue hidrolizada con pepsina-pancreatina, generándose una fracción peptídica (> 10 kDa) por ultrafiltración. Se utilizaron cinco grupos de ratas (uno de normoglucémicas y cuatro de diabetizadas con aloxano). Se realizó una curva de tolerancia a la sacarosa, proporcionándoles el disacárido antes de la medición. La sangre se tomó de la punta de la cola a los 0, 30, 60, 90 y 120 minutos. Resultados: el contenido proteico de la harina fue del 49,51 %. La fracción peptídica (> 10 kDa) presentó un 91 % de proteína; de esta se suministró una dosis de 50 mg/kg que demostró una tendencia a la disminución de la glucosa sanguínea en la primera hora, aunque no se encontró significancia entre el blanco y las dosis evaluadas. No hubo disminución de la absorción de glucosa frente al fármaco de referencia. A los 120 min del periodo postprandial no se encontraron diferencias entre las dosis, el blanco y la acarbosa, lo que denota un retorno al estado basal. Los valores en las ratas diabetizadas fueron opuestos a los de la acarbosa, por lo que no existió relación entre el mecanismo de acción del fármaco con el efecto analizado. Conclusión: las fracciones peptídicas de chía de > 10 kDa no presentaron efecto hipoglucemiante con la dosis única suministrada. (AU)

Introduction: diabetes research with peptides from foods has been conducted in animal experiments to be later applied to humans. Objective: the main purpose of this work was to evaluate in rats the hypoglycemic effect of a peptide fraction of chia seeds derived by enzymatic hydrolysis. Materials and methods: from chia flour a protein-rich fraction was obtained, which was hydrolyzed with pepsin-pancreatin system enzymes to yield a peptide fraction (> 10 kDa) by ultrafiltration. Five rat groups (one normoglycemic and four diabetized with alloxan) were used. A sucrose tolerance curve was performed, providing the disaccharide before measurement. Blood was taken from the tip of the tail at 0 (before sugar), 30, 60, 90, and 120 minutes. Results: the protein content of chia flour was 49.51 %. The peptide fraction (> 10 kDa) had 91 % of protein. A dose of 50 mg/kg showed in rats a tendency to decrease blood glucose within the first hour, but no significance was found between the target and the doses evaluated. There was no decrease in glucose absorption vs. the reference drug. At 120 min postprandial, no differences were found between doses, water, and acarbose, showing a return to the baseline status. The tolerance curve in diabetic rats was opposite to that of acarbose, so there was no relationship between the drug's mechanism of action and this analyzed effect. Conclusion: the peptide fraction of chia of > 10 kDa showed no hypoglycemic effect at the single dose that was administered. (AU)

Glycemia-reducing effects of Bolivian nutraceutical plants / Efectos reductores de la glucemia de las plantas nutracéuticas bolivianas

INTRODUCTION: The prevalence of diabetes type 2 is increasing worldwide, thus the search of novel alternative ther¬apies is needed. According to their traditional use, we selected five Bolivian plants Chenopodium quinoa (CQ) Ama¬ranthus caudatus (AC), Chenopodium pallidicaule (CP), Lupinus mutabilis (LM) and Smallanthus sonchifolius (SS) that are traditionally used to control glycemia. METHODS: The effect of a single oral administration of Ethanolic (EtOH), hydro-ethanolic (EtOH70) and aqueous (Aq) extracts from all plant species were tested for their effect on blood glucose in non-fasted mice and during the oral glucose tolerance test (OGTT). The effect on insulin secretion was evaluated in mice pancreatic islets. RESULTS: EtOH70 extracts of all the plants showed glucose-reducing effect at the highest dose evaluated (2000 mg/ kg b.w.). EtOH70 extracts improved the glucose tolerance evaluated by the OGTT in mice fasted for 12 hours. The extracts have different effects on glucose homeostasis since just extracts of AC, LM and CQ but not CP and SS in¬creased insulin secretion as shown on mice pancreatic islets. The phytochemical qualitative characterization of EtOH70 extracts detected phenolic acids and flavonoids in AC, CP and CQ; alkaloids in LM and anthocyanidins in SS. None of EtOH70 extracts tested showed in vitro or in vivo acute toxicity at concentrations where they exhibit glucose lowering effects. CONCLUSIONS: We report here that extracts from AC, CQ, CP, LM and SS exhibit glucose lowering effect while just AC, CQ and LM stimulate directly the insulin secretion

INTRODUCCIÓN: La prevalencia de diabetes tipo 2 está aumentando en todo el mundo, por lo que se necesita la búsqueda de nuevas terapias alternativas. Según su uso tradicional, seleccionamos cinco plantas bolivianas Chenopodium quinoa (CQ) Amaranthus caudatus (AC), Chenopodium pallidicaule (CP), Lupinus mutabilis (LM) y Smallanthus sonchifolius (SS) que se usan tradicionalmente para controlar la glucemia. MÉTODOS: Se evaluó el efecto de la administración oral única de extractos etanólicos (EtOH), hidroetanólicos (EtOH70) y acuosos (Aq) de las plantas mencionadas para determinar su efecto sobre la glucosa en sangre en ratones en o sin ayunas y durante la prueba de tolerancia a la glucosa oral (PTGO). El efecto sobre la secreción de insulina se evaluó en islotes pancreáticos de ratones. RESULTADOS: Los extractos de EtOH70 de todas las plantas disminuyeron la glucemia a la dosis más alta evaluada (2000 mg / kg b.w.). Los extractos de EtOH70 mejoraron la tolerancia a la glucosa evaluada mediante la PTGO en ratones con ayuno de 12 horas. Los extractos tienen diferentes efectos sobre la homeostasis de la glucosa, ya que solo los extractos de AC, LM y CQ pero no CP y SS aumentaron la secreción de insulina como se muestra en los islotes pancreáticos de los ratones. La caracterización cualitativa fitoquímica de extractos de EtOH70 detectó ácidos fenólicos y flavonoides en AC, CP y CQ, alcaloides en LM y antocianidinas en SS. Ninguno de los extractos de EtOH70 probados mostró toxicidad aguda in vitro o in vivo a concentraciones en las que exhiben efectos reductores de glucosa. CONCLUSIÓN: Los extractos de AC, CQ, CP, LM y SS exhiben un efecto reductor de la glucosa, mientras que solo AC, CQ y LM estimulan directamente la secreción de insulina

Morphological changes in the sphenopalatine ganglion on the background of metabolic disorders in the experiment at rats

The sphenopalatine ganglion occupies a special place in neuropathology and dental neuropathy, accompanied by such pronounced symptoms as "vegetative storm". The aim of the research was obtaining information on the external structure of the sphenopalatine ganglion, the morphometric characteristics of its neurons in norm and in experimental diabetes. The study was carried out on male Wistar rats weighing 260-300 g: with a stereoscopic biological microscope, using ophthalmic instruments, we removed almost the entire gland that was not accompanied by significant bleeding under general anesthesia. Peculiarities of the external structure of the sphenopalatine ganglion of the white rat were studied by macro-micro preparations under a binocular microscope at 50 objects pervaded with silver nitrate, according to Christen-sen

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A surgical study about jejunum: the exclusion to nutrients flow. A novel strategical technique

The bariatric surgery techniques applied in patients with obesity have reported a great ability to improve Type 2 Diabetes mellitus (T2DM). Some published data report an increasing betacell mass in some surgical processes. This mechanism was specially seen in the bariatric surgeries which affect the length of the small bowel. The intrinsic mechanism that links both phenomena seemed to be related to the enterohormonal secretion pattern. Many enteral hormones have been invoked as the effector of these mechanisms. Previous reports focused on the medial portion of jejunum, as the precise place in which some particular enterohormones determine the homeostatic glycemic improvement. Goto-Kakizaki diabetic male rats underwent surgery to exclude the 50% medial jejunum from the normal nutrients flow. This medial portion of jejunum was not resected, but anastomosed by both extremes to the abdominal wall, and a stoma was performed. This surgery wasnamed as Medial Jejunal Exclusion (MJE). We studied the functional parameters in a three-month survival period. In this sense basal glycaemia, weight increase and food intake were not modified between the surgical and control groups. The study presented a mortality of the 24%. This model was designed for the late study of serum and enterohormones release in this jejunal portion, excluded of nutrients flow. We report a new surgical technique, which appears to balance the homeostatic processes in order to maintain the survival of diabetic rats. Thus, this mechanism could be in the basis of T2DM improvement, and this novel surgical model will help study this precise portion of jejunum

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Effects of W100E-Leptin in streptozotocin-induced diabetic mice

OBJECTIVES: To determine the effects of W100E-Leptin in a streptozotocin-induced diabetic mice model (effects in the body weight, fasting serum glucose and glucose tolerance). METHODS: Intraperitoneal W100E-Leptin application at 1 mg/kg for 13 days. We used 3 experimental groups (n=6). Group 1: Diabetes + W100E-Leptin (intraperitoneal administration), Group 2: Diabetes + buffer (vehicle) and Group 3: Healthy control + buffer (vehicle). RESULTS: We determined the effects of W100E on the behavior of the mice, more active, more hair and a tendency to gain body weight. We did not observe any hypoglycemic effect of W100E-Leptin on serum glucose levels in the tests we performed. CONCLUSIONS: These results show us the need to characterize the effects of this hormone in diabetes. We will continue with the characterization of the change that is generated in the protein regulation caused by W100E-Leptin in the diabetes, to propose this hormone as an adjunct against diabetes

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Tratamiento alogénico con células troncales mesenquimales sobre la isquemia crítica en un modelo murino diabético / Alogenic treatment with mesenquimal trunk cells on the critical ischemia in a diabetic murine model

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Investigation of dose-dependent effects of berberine against renal ischemia/reperfusion injury in experimental diabetic rats / Investigación de los efectos dependientes de dosis de la berberina contra la lesión de isquemia/reperfusión renal en ratas diabéticas experimentales

BACKGROUND: Ischemia-reperfusion injury causes various severe morphological and functional changes in diabetic patients. To date, numerous antidiabetic and antioxidant agents have been used for treatment of the disease-related changes. OBJECTIVES: We aimed to examine effective therapeutic doses or doses of berberine against renal ischemia/reperfusion injury (IRI) in a streptozotocin (STZ)-induced diabetic rat model by histopathological and biochemical analysis. METHODS: Thirty male Sprague Dawley rats were treated with STZ injection for the development of diabetes, and divided into the following groups: STZ-induced diabetic group (STZ); IRI-induced diabetic group (STZ + IRI); 50 mg/kg berberine (BRB) treated diabetic group after inducing IRI (STZ + IRI + BRB1); 100 mg/kg BRB treated diabetic group after IRI (STZ + IRI + BRB2); 150 mg/kg BRB treated diabetic group after IRI (STZ + IRI + BRB3). Bilateral renal ischemia model was applied for 45min, then reperfusion was allowed for 14 days in STZ-induced diabetic rats. Renal injury was detected histopathologically. Blood urea nitrogen (BUN), creatinine and lactate dehydrogenase (LDH) levels were measured in serum using the ELISA method. Total antioxidant status (TAS) and total oxidant status (TOS) of renal tissue was studied by spectrophotometric assay. Oxidative stress index (OSI) was calculated as TOS-to-TAS ratio. Tumor necrosis factor alpha (TNF-alfa), C-reactive protein (CRP), Na+/K+-ATPase (sodium pump), and Ca2+-ATPase (calcium ATPase) enzyme levels were measured in tissues using the ELISA method. Anti-apoptotic Bax and pro-apoptotic Bcl-2 protein levels were detected by Western blot analysis. All data were evaluated statistically. RESULTS: The highest histopathological score was detected in the STZ+IRI group compared to the other group. BRB administration at the doses of 100mg/kg and 150 mg/kg markedly improved renal injury. BUN and creatinine levels significantly increased in the STZ+IRI group compared to the STZ group (p < 0.001). 100 mg/kg and 150 mg/kg BRB administration significantly decreased those levels (p < 0.01). The highest TOS and the lowest TAS levels were detected in the STZ+IRI group (p < 0.001). IRI markedly aggravated inflammation via increasing levels of TNF-Alpha and CRP (< 0.001), and caused apoptosis via inducing Bcl-2 protein, and suppressing Bax protein (p < 0.001). BRB administration at the doses of 100 mg/kg and 150 mg/kg showed anti-oxidant, anti-inflammatory and anti-apoptotic effects (p < 0.01). The LDH enzyme, was used as a necrosis marker, was higher in the STZ+IRI group than other groups. BRB administration at all of the doses, resulted in the decline of LDH enzyme level (p < 0.001). Ca2+-ATPase and Na+/K+-ATPase enzyme activities decreased in the STZ+IRI group compared to the STZ group (p < 0.001), while BRB administration at the doses of 100 mg/kg and 150mg/kg significantly increased those of enzyme activities, respectively (p < 0.05). CONCLUSION: Ischemia with diabetes caused severe histopathological and biochemical damage in renal tissue. The high doses of berberine markedly improved histopathological findings, regulated kidney function via decreasing BUN and creatinine levels, and rearranged intercellular ion concentration via increasing Na+/K+-ATPase and Ca2+- ATPase levels. Berberine showed anti-oxidant, anti-apoptotic, and anti-inflammatory effects. According to these data, we suggest that berberine at the doses of 100 and 150 mg may be used as a potential therapeutic agent to prevent renal ischemic injury

ANTECEDENTES: La reperfusión de la isquemia provoca graves cambios morfológicos y funcionales en los pacientes diabéticos. Hasta la fecha numerosos antidiabéticos y agentes antioxidantes han sido utilizados para el tratamiento de los cambios relacionados con la enfermedad. OBJETIVOS: El objetivo fue examinar las dosis terapéuticas efectivas o las dosis de berberina (BRB) frente a la insuficiencia renal por isquemia/reperfusión (IRI) en estreptozotocina (STZ) inducida por el modelo de rata por análisis histopatológico y bioquímico. MÉTODOS: Treinta ratas machos Spraque-Dawley fueron tratadas con inyección de STZ para el desarrollo de diabetes, se dividieron en los siguientes grupos: grupo diabético inducido por STZ; grupo diabético inducido por IRI (STZ + IRI); grupo diabético tratado con 50 mg/kg de BRB después de la inducción de IRI (STZ + IRI + BRB1); grupo diabético tratado con 100 mg/kg de BRB después de IRI (STZ + IRI + BRB2), y grupo diabético tratado con 150 mg/kg de BRB después de IRI (STZ + IRI + BRB3). Se aplicó un modelo de isquemia renal bilateral durante 45min, luego se permitió la reperfusión durante 14 días en ratas diabéticas inducidas por STZ. La lesión renal fue detectada histopatológicamente. Los niveles de nitrógeno ureico en sangre (BUN), creatinina y lactato deshidrogenasa (LDH) se midieron en suero por el método ELISA. El estado antioxidante total (TAS) y el estado oxidante total (TOS) del tejido renal se estudiaron mediante un ensayo espectrofotométrico. El índice de estrés oxidativo (OSI) fue calculado como la relación TOS-a-TAS. El factor de necrosis tumoral alfa (TNF-alfa), proteína C reactiva (CRP), Na+/K+-ATPasa (bomba de sodio) y la Ca2+-ATPasa (calcio ATPasa) de la enzima se midieron los niveles en los tejidos mediante el método ELISA. Los niveles de proteína anti-apoptótica Bax y pro-apoptótica Bcl-2 se detectaron por el análisis de Western blot. Todos los datos fueron evaluados estadísticamente. RESULTADOS: La mayor puntuación histopatológica fue detectada en el grupo STZ + IRI en comparación con el otro grupo. La administración de BRB en dosis de 100 y 150 mg/kg mejoró notablemente la lesión renal. Los niveles de BUN y creatinina aumentaron significativamente en el grupo STZ+IRI en comparación con el grupo STZ (p < 0,001). La administración de 100 y 150 mg/kg de BRB disminuyó significativamente esos niveles (p < 0,01). Los TOS más altos y los niveles más bajos de TAS se detectaron en el grupo STZ+IRI (p < 0,001). El IRI agravó notablemente la inflamación a través del aumento de los niveles de TNF-alfa y de PCR (< 0,001), y causó la apoptosis a través de la inducción de la proteína Bcl-2 y la supresión de la proteína Bax (p < 0,001). La administración de BRB con las dosis de 100 y 150mg/kg mostró efectos antioxidante, antiinflamatorio y antiapoptóticos (p < 0,01). La enzima LDH que se usó como marcador de necrosis fue mayor en el grupo STZ + IRI que en los otros grupos. La administración de BRB en todas las dosis, dio lugar a una disminución del nivel de la enzima LDH (p < 0,001). Las actividades de las enzimas Ca2+-ATPasa y Na+/K+-ATPasa disminuyeron en el grupo STZ + IRI en comparación con el grupo STZ (p < 0,001, mientras que la administración de BRB en dosis de 100 y 150 mg/kg incrementó significativamente las actividades de las enzimas, respectivamente (p < 0,05). CONCLUSIÓN: La isquemia con diabetes causó graves daños histopatológicos y bioquímicos en el tejido renal. Las altas dosis de BRB mejoraron notablemente los hallazgos histopatológicos, la función renal regulada a través de la disminución de los niveles de BUN y creatinina, y la concentración de iones intercelulares reordenados mediante el aumento de los niveles de Na+/K+-ATPasa y la Ca2+-ATPasa. La BRB mostró efectos antioxidantes, antiapoptóticos y antiinflamatorios. De acuerdo con estos datos, sugerimos que la BRB en dosis de 100 y 150 mg se puede usar como un agente terapéutico potencial para prevenir la lesión isquémica renal

Characterization of potent antidiabetic compounds from Costus pictus D. Don found in Assam, India using in vitro in vivo methods / Caracterización de compuestos antidiabéticos potentes de Costus pictus D. Don encontrados en Assam, India usando métodos in vitro e in vivo

Objective: Costus pictus D. Don is a traditionally used plant in Naojan area of Golaghat district of Assam, India specifically for treating diabetes. Six compounds were isolated from standardized methanolic extract of the aerial parts (MECP). The prime objective was to select most potent antidiabetic compounds among the isolated compounds viz. F67, F12, F16, F3032, F37 & F48 by using in vitro and in vivo methods. Methods: Isolated compounds were subjected to initial screening by in vitro alfa-amylase inhibition activity assay using iodine-starch and DNSA (3,5-dinitrosalicylic acid) methods. Compounds depicting promising in vitro activity were selected for in vivo Streptozotocin (STZ) induced antidiabetic screening activity. Then based on the in vivo results, most potent compounds were selected for instrumental characterization by Q-TOF ESI-MS, 1HNMR, 13CNMR & FTIR. Results: Amongst the six compounds isolated from MECP, three compounds viz. F12, F16 & F48 showed potent in vitro activity. They were subsequently subjected to evaluation of the antidiabetic activity in vivo by oral administration, at dose of 10, 20 & 50 mg/kg body weight respectively, using Wister rat (120-150 g) and Glibenclamide (10mg/k body weight) as standard. Two compounds, F12 and F48 at dose of 50 mg/kg body weight, reversed STZ induced diabetic parameters (increased blood glucose level, altered plasma profile and histoarchitecture of the pancreatic and hepatic cells) with statistical significance (P<0.05), that was comparable with the standard. Hence, instrumental characterization by Q-TOF ESI-MS, 1HNMR, 13CNMR & FTIR of compounds F12 and F48 isolated from MECP was carried out which established their identity as (3,5,7-Trihydroxy-3'-hydroxy-4'-methoxy) flavanone or [3,5,7-Trihydroxy-2-(3'-hydroxy-4'-methoxy phenyl)-2,3-dihydrochromen-4-one] and 3,5,8-trihydroxy-7-methoxy-2-phenyl-2,3-dihydrochromen-4-one or [7-methoxy-3, 5, 8 trihydroxy flavanone] respectively. Conclusion: The study culminated in elucidation of two flavanones as most potent compounds in exhibiting antidiabetic activities. The findings were thus successful in validating the traditional practices in Golaghat district of Assam, India, associated with the use of Costus pictus D. Don in the treatment of diabetes

Objetivo: Costus pictus D. Don es una planta usada tradicionalmente en la zona del distrito de Golaghat Naojan de Assam, India específicamente para el tratamiento de la diabetes. Seis compuestos se aislaron a partir de extracto metanólico estandarizados de las hojas (MECP). El principal objetivo fue seleccionar compuestos antidiabéticos más potentes entre los compuestos aislados viz. F67, F12, F16, F3032, F37 y F48 mediante métodos in vitro e in vivo. Métodos: Los compuestos aislados fueron sometidos a cribado inicial mediante ensayo de actividad de inhibición in vitro alfa-amilasa utilizando yodo-almidón y métodos DNSA (ácido 3,5-dinitrosalicilico). Los compuestos que presentaban una actividad in vitro prometedora se seleccionaron para la actividad de cribado antidiabético inducida por estreptozotocina (STZ) in vivo. En función de los resultados in vivo, la mayoría de los compuestos potentes se seleccionaron para la caracterización instrumental por Q-TOF ESI-MS, 1HNMR, 13CNMR y FTIR. Resultados: Entre los seis compuestos aislados de MECP, tres compuestos viz. F12, F16 y F48 mostraron una potente actividad. Posteriormente se sometieron a evaluación de la actividad antidiabética in vivo mediante administración oral, en dosis de 10, 20 y 50 mg / kg peso, utilizando ratas Wister (120-150 g) y glibenclamida (10 mg / kg peso) como estándar. Dos compuestos, F12 y F48 en dosis de 50 mg/kg peso, revirtieron los parámetros diabéticos inducidos por STZ (aumento del nivel de glucosa en sangre, plasma perfil alterado y histoarquitectura del páncreas y células hepáticas), con significación estadística (P<0,05) que era comparable con la norma. Se llevo a cabo la caracterización instrumental por Q-TOF ESI-MS, RMN 1H, RMN 13C y FTIR de los compuestos F12 y F48 aislado de MECP, lo que estableció su identidad como (3,5,7-trihidroxi-3'-hidroxi-4'- metoxi) flavanona o [3,5,7-trihidroxi-2- (fenil 3'-hidroxi-4'-metoxi) -2,3-dihydrochromen-4-ona] y 3,5,8-trihidroxi-7-metoxi -2-fenil-2,3-dihydrochromen-4-ona o [7-metoxi-3, 5, 8 trihidroxi flavanona] respectivamente. Conclusión: El estudio culminó en la elucidación de dos flavanonas como los compuestos más potentes en la exposición de actividades antidiabéticas. Los resultados lograron validar las prácticas tradicionales en el distrito de Golaghat de Assam, India, asociados con el uso de Costus pictus D. Don en el tratamiento de la diabetes

Efectos del tungstato de sodio y sulfato de vanadilo sobre la liberación de prostanoides del lecho vascular mesentérico de ratas diabéticas / Effects of sodium tungstate and vanadyl sulphate on the liberation of prostanoids of the mesenteric vascular bed in diabetic rats

La pérdida del rol modulador del endotelio podría estar implicada en la patogénesis de las complicaciones vasculares diabéticas. Los compuestos de metales de transición tales como wolframio y vanadio se han propuesto como posibles agentes en el tratamiento de la diabetes al simular los efectos de la insulina. El lecho vascular mesentérico interviene en la resistencia vascular y constituye una fuente de compuestos vasoactivos como los prostanoides. El objetivo de este trabajo fue estudiar los efectos de los tratamientos con tungstato de sodio y sulfato de vanadilo sobre los parámetros metabólicos y la liberación de prostanoides del lecho vascular mesentérico en un modelo experimental de diabetes inducida por estreptozotocina. En ratas diabéticas se observó un aumento significativo de los niveles plasmáticos de glucosa, triglicéridos y colesterol total. Por su parte, se observó una reducción significativa en la liberación de los prostanoides vasodilatadores como la prostaciclina y la prostaglandina E2 y del vasoconstrictor tromboxano A2 por el lecho vascular mesentérico. Tanto el tungstato de sodio como el sulfato de vanadilo normalizaron la glucemia, la trigliceridemia y la colesterolemia en las ratas diabéticas. Por otra parte, solo el tratamiento con tungstato de sodio revirtió la reducción en la liberación de prostanoides vasodilatadores, mejorando en los animales diabéticos la relación prostaciclina/tromboxano, un indicador de disfunción vascular. En conclusión, a diferencia del sulfato de vanadilo, el tungstato de sodio demuestra ser más eficaz para controlar las alteraciones metabólicas y de la producción de prostanoides vasodilatadores observadas en la diabetes experimental inducida por estreptozotocina

The loss of the modulator role of the endothelium could be involved in the pathogenesis of diabetic vascular complications. Transition metal compounds, such as tungsten and vanadium, have been proposed as possible agents in the treatment of diabetes by simulating the effects of insulin. The mesenteric vascular bed intervenes in vascular resistance and is a source of vasoactive compounds, such as prostanoids. The aim of this work was to study the effects of sodium tungstate and vanadyl sulphate treatments on the metabolic parameters and the release of prostanoids of the mesenteric vascular bed in an experimental model of Streptozotocin-induced diabetes. In diabetic rats, a significant increase was observed in plasma levels of glucose, triglycerides and total cholesterol. On the other hand, there was a significant reduction in the release of vasodilator prostanoids, such as prostacyclin and prostaglandin E2 and vasoconstrictor thromboxane A2 through the mesenteric vascular bed. Both sodium tungstate and vanadyl sulphate normalised glycaemia, triglyceridaemia and cholesterolaemia in rats diabetics. On the other hand, only treatment with sodium tungstate reversed the reduction in the release of vasodilator prostanoids, improving in diabetic animals the prostacyclin/thromboxane ratio, an indicator of vascular dysfunction. In conclusion, unlike vanadyl sulphate, sodium tungstate is shown to be more effective in controlling metabolic changes and the production of vasodilator prostanoids observed in experimental diabetes induced by streptozotocin

Metabolomic analysis and biochemical changes in the urine and serum of streptozotocin-induced normal- and obese-diabetic rats

Diabetes mellitus (DM) is a chronic disease that can affect metabolism of glucose and other metabolites. In this study, the normal- and obese-diabetic rats were compared to understand the diabetes disorders of type 1 and 2 diabetes mellitus. This was done by evaluating their urine metabolites using proton nuclear magnetic resonance (1H NMR)-based metabolomics and comparing with controls at different time points, considering the induction periods of obesity and diabetes. The biochemical parameters of the serum were also investigated. The obese-diabetic model was developed by feeding the rats a high-fat diet and inducing diabetic conditions with a low dose of streptozotocin (STZ) (25 mg/kg bw). However, the normal rats were induced by a high dose of STZ (55 mg/kg bw). A partial least squares discriminant analysis (PLS-DA) model showed the biomarkers of both DM types compared to control. The synthesis and degradation of ketone bodies, tricarboxylic (TCA) cycles, and amino acid pathways were the ones most involved in the variation with the highest impact. The diabetic groups also exhibited a noticeable increase in the plasma glucose level and lipid profile disorders compared to the control. There was also an increase in the plasma cholesterol and low-density lipoprotein (LDL) levels and a decline in the high-density lipoprotein (HDL) of diabetic rats. The normal-diabetic rats exhibited the highest effect of all parameters compared to the obese-diabetic rats in the advancement of the DM period. This finding can build a platform to understand the metabolic and biochemical complications of both types of DM and can generate ideas for finding targeted drugs

FPS-ZM1 and valsartan combination protects better against glomerular filtration barrier damage in streptozotocin-induced diabetic rats

Despite the effectiveness of renin-angiotensin blockade in retarding diabetic nephropathy progression, a considerable number of patients still develop end-stage renal disease. The present investigation aims to evaluate the protective potential of FPS-ZM1, a selective inhibitor of receptor for advanced glycation end products (RAGE), alone and in combination with valsartan, an angiotensin receptor blocker, against glomerular injury parameters in streptozotocin-induced diabetic rats. FPS-ZM1 at 1 mg/kg (i.p.), valsartan at 100 mg/kg (p.o.), and their combination were administered for 4 weeks, starting 2 months after diabetes induction in rats. Tests for kidney function, glomerular filtration barrier, and podocyte slit diaphragm integrities were performed. Combined FPS-ZM1/valsartan attenuated diabetes-induced elevations in renal levels of RAGE and phosphorylated NF-κB p65 subunit. It ameliorated glomerular injury due to diabetes by increasing glomerular nephrin and synaptopodin expressions, mitigating renal integrin-linked kinase (ILK) levels, and lowering urinary albumin, collagen type IV, and podocin excretions. FPS-ZM1 also improved renal function as demonstrated by decreasing levels of serum cystatin C. Additionally, the combination also alleviated indices of renal inflammation as revealed by decreased renal monocyte chemoattractant protein 1 (MCP-1) and chemokine (C-X-C motif) ligand 12 (CXCL12) expressions, F4/80-positive macrophages, glomerular TUNEL-positive cells, and urinary alpha-1-acid glycoprotein (AGP) levels. These findings underline the benefits of FPS-ZM1 added to valsartan in alleviating renal glomerular injury evoked by diabetes in streptozotocin rats and suggest FPS-ZM1 as a new potential adjunct to the conventional renin-angiotensin blockade

Modulation of diabetes-related liver injury by the HMGB1/TLR4 inflammatory pathway

Chronic inflammation plays an essential role in the development of diabetic complications. Understanding the molecular mechanisms that support inflammation is a prerequisite for the design of novel anti-inflammatory therapies. These would take into consideration circulating levels of cytokines and damage-associated molecular patterns (DAMPs) that include the high mobility group box 1 (HMGB1) protein which, in part, promotes the inflammatory response through TLR4 signaling. The liver, as the source of circulating cytokines and acute-phase proteins, contributes to the control of systemic inflammation. We previously found that liver injury in streptozotocin-induced diabetic rats correlated with the level of oxidative stress, increased expression of HMGB1, and with the activation of TLR4-mediated cell death pathways. In the present work, we examined the effects of ethyl pyruvate (EP), an inhibitor of HMGB1 release/expression, on the modulation of activation of the HMGB1/TLR4 inflammatory cascade in diabetic liver. We observed that increased expression of inflammatory markers, TNF-α, IL-6, and haptoglobin in diabetic liver was associated with increased HMGB1/TLR4 interaction, activation of MAPK (p38, ERK, JNK)/NF-κB p65 and JAK1/STAT3 signaling pathways, and with decreased expression of Nrf2-regulated antioxidative enzymes. The reduction in HMGB1 expression as the result of EP administration reduced the pro-inflammatory activity of HMGB1 and exerted a protective effect on diabetic liver, which was observed as improved liver histology and antioxidant and inflammatory statuses. Our results suggest that prevention of HMGB1 release and blockage of the HMGB/TLR4 axis represents a potentially effective therapeutic strategy aimed at ameliorating diabetes-induced inflammation and ensuing liver injury

Oxidative stress-dependent contribution of HMGB1 to the interplay between apoptosis and autophagy in diabetic rat liver

The progression of oxidative stress, resulting cell damage, and cell death underlies the etiology of liver damage/dysfunction as a complication of diabetes. High-mobility group box 1 (HMGB1) protein, a chromatin-binding nuclear protein and damage-associated molecular pattern molecule, is integral to oxidative stress and signaling pathways regulating cell death and cell survival. We previously found that in streptozotocin (STZ)-induced diabetic rats, reduction of oxidative stress after melatonin administration lowered necrotic cell death and increased expression of HMGB1 and hepatocellular damage. In the present study, we examined whether alleviation of diabetes-attendant oxidative stress and ensuing change in HMGB1 expression influence the dynamic equilibrium between apoptosis/autophagy and liver damage. We observed that elevated HMGB1 protein levels in diabetic rat liver accompanied increased interactions of HMGB1 with TLR4 and RAGE, and activation of the intrinsic apoptotic pathway and Beclin 1-dependent autophagy. The absence of p62 degradation in diabetic rat liver pointed to defective autophagy which was responsible for lower autophagosome/autophagolyso some formation and an increased apoptosis/autophagy ratio. Compared to diabetic rats, in melatonin-treated diabetic rats, the structure of liver cells was preserved, HMGB1/TLR4 interaction and downstream apoptotic signaling were significantly reduced, HMGB1/Beclin 1 colocalization and interactions were augmented and Beclin 1-mediated autophagy, mithophagy in particular, were increased. We concluded that in mild oxidative stress, HMGB1 is cytoprotective, whereas in intense oxidative stress, HMGB1 actions promote cell death and liver damage. Since reduced HMGB1 binds to RAGE but not to TLR4, redox modification of HMGB1 as a mechanism regulating the cross-talk between apoptosis and autophagy in diabetes is discussed

Effects of exendin-4 and selenium on the expression of GLP-1R, IRS-1, and preproinsulin in the pancreas of diabetic rats

The mechanisms by which exendin-4 and selenium exert their antidiabetic actions are still unclear. Here, we investigated the effects of exendin-4 or selenium administration on the expression of glucagon-like peptide-1 receptor (GLP-1R), insulin receptor substrate-1 (IRS-1), and preproinsulin in the pancreas of diabetic rats. Diabetes was induced by streptozotocin administration. Diabetic rats were injected intraperitoneally with 0.03 μg exendin-4/kg body weight/daily or treated with 5 ppm selenium in drinking water for a period of 4 weeks. GLP-1R and IRS-1 levels were decreased while the level of preproinsulin messenger RNA (mRNA) was increased in the pancreas of diabetic untreated rats, as compared to that in control rats. Treatment of diabetic rats with exendin-4 increased protein and mRNA levels of GLP-1R, and IRS-1, and the mRNA level of preproinsulin in the pancreas, as compared to their levels in diabetic untreated rats. Selenium treatment of diabetic rats increased the pancreatic mRNA levels of GLP-1R, IRS-1, and preproinsulin. Exendin-4 or selenium treatment of diabetic rats also increased the numbers of pancreatic islets and GLP-1R molecules in the pancreas. Therefore, exendin-4 and selenium may exert their antidiabetic effects by increasing GLP-1R, IRS-1, and preproinsulin expression in the pancreas and by increasing the number of pancreatic islets

Myo-inositol inhibits intestinal glucose absorption and promotes muscle glucose uptake: a dual approach study

The present study investigated the effects of myo-inositol on muscle glucose uptake and intestinal glucose absorption ex vivo as well as in normal and type 2 diabetes model of rats. In ex vivo study, both intestinal glucose absorption and muscle glucose uptake were studied in isolated rat jejunum and psoas muscle respectively in the presence of increasing concentrations (2.5 % to 20 %) of myo-inositol. In the in vivo study, the effect of a single bolus dose (1 g/kg bw) of oral myo-inositol on intestinal glucose absorption, blood glucose, gastric emptying and digesta transit was investigated in normal and type 2 diabetic rats after 1 h of co-administration with 2 g/kg bw glucose, when phenol red was used as a recovery marker. Myo-inositol inhibited intestinal glucose absorption (IC50 = 28.23 ± 6.01 %) and increased muscle glucose uptake, with (GU50 = 2.68 ± 0.75 %) or without (GU50 = 8.61 ± 0.55 %) insulin. Additionally, oral myo-inositol not only inhibited duodenal glucose absorption and reduced blood glucose increase, but also delayed gastric emptying and accelerated digesta transit in both normal and diabetic animals. Results of this study suggest that dietary myo-inositol inhibits intestinal glucose absorption both in ex vivo and in normal or diabetic rats and also promotes muscle glucose uptake in ex vivo condition. Hence, myo-inositol may be further investigated as a possible anti-hyperglycaemic dietary supplement for diabetic foods and food products (AU)

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