RESUMEN

11ß-Hydroxysteroid dehydrogenase type 1 (11ß-HSD1) is the only enzyme that converts inactive glucocorticoids to active forms and plays an important role in the regulation of glucocorticoid action in target tissues. JTT-654 is a selective 11ß-HSD1 inhibitor and we investigated its pharmacological properties in cortisone-treated rats and non-obese type 2 diabetic Goto-Kakizaki (GK) rats because Asians, including Japanese, are more likely to have non-obese type 2 diabetics. Systemic cortisone treatment increased fasting plasma glucose and insulin levels and impaired insulin action on glucose disposal rate and hepatic glucose production assessed by hyperinsulinemic-euglycemic clamp, but all these effects were attenuated by JTT-654 administration. Cortisone treatment also reduced basal and insulin-stimulated glucose oxidation in adipose tissue, increased plasma glucose levels after administration of the pyruvate, the substrate of gluconeogenesis, and increased liver glycogen content. Administration of JTT-654 also inhibited all of these effects. Cortisone treatment decreased basal and insulin-stimulated 2-deoxy-D-[1-3H]-glucose uptake in 3T3-L1 adipocytes and increased the release of free fatty acids and glycerol, a gluconeogenic substrate, from 3T3-L1 adipocytes, and JTT-654 significantly attenuated these effects. In GK rats, JTT-654 treatment significantly reduced fasting plasma glucose and insulin levels, enhanced insulin-stimulated glucose oxidation in adipose tissue, and suppressed hepatic gluconeogenesis as assessed by pyruvate administration. These results demonstrated that glucocorticoid was involved in the pathology of diabetes in GK rats, as in cortisone-treated rats, and that JTT-654 ameliorated the diabetic conditions. Our results suggest that JTT-654 ameliorates insulin resistance and non-obese type 2 diabetes by inhibiting adipose tissue and liver 11ß-HSD1.

Asunto(s)

Cortisona , Diabetes Mellitus Tipo 2 , Resistencia a la Insulina , Ratas , Animales , Glucocorticoides/uso terapéutico , 11-beta-Hidroxiesteroide Deshidrogenasa de Tipo 1 , Cortisona/uso terapéutico , Cortisona/farmacología , Glucemia , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Obesidad/patología , Insulina , Glucosa

RESUMEN

Objective: This study aimed to determine the change of gastrointestinal (GI) emptying time after ileal interposition (IT) and elucidate the role of altered GI peristalsis in diabetic control. Materials and Methods: Twelve male Goto-Kakizaki rats were randomly divided into IT and sham groups. Body weight and food intake were recorded. Oral glucose tolerance test (OGTT), insulin tolerance test (ITT), plasma glucagon-like peptide-1 (GLP-1), and gastric emptying were measured at baseline and 4 and 8 weeks after operation. At 9 weeks postoperatively, the rats in the IT group were given atropine which can suppress the emptying of stomach and upper intestine, while sham rats were given metoclopramide (to expedite gastric emptying) for 1 week. At week 10 postoperatively, OGTT and GLP-1 were detected. The intestinal transit was tested at postoperative 12 weeks. Results: No differences were found between groups at baseline. After operation, the IT rats had lower body weight than sham rats. At 4 and 8 weeks postoperatively, the IT group showed better OGTT and ITT, with significantly elevated GLP-1 relative to sham. After administration of the GI motility drugs, however, the effect of diabetic control for the two groups became similar. The GI transit after IT was significantly slower than sham at all tested time points. Conclusions: Although IT inhibits the GI transit time, the earlier interaction between undigested nutrients and interpositioned ileum promotes gut hormone secretion and thus reduces body weight and alleviates hyperglycemia. A decrease of GI transit of IT rats exacerbates the antidiabetic effects.

Asunto(s)

Diabetes Mellitus , Tránsito Gastrointestinal , Animales , Glucemia , Peso Corporal , Vaciamiento Gástrico , Péptido 1 Similar al Glucagón , Íleon/cirugía , Masculino , Ratas

RESUMEN

Purinergic P2Y receptors, by binding adenosine triphosphate (ATP), are known for enhancing glucose-stimulated insulin secretion (GSIS) in pancreatic ß cells. However, the impact of these receptors in the actin dynamics and insulin granule exocytosis in these cells is not established, neither in normal nor in glucotoxic environment. In this study, we investigate the involvement of P2Y receptors on the behavior of insulin granules and the subcortical actin network dynamics in INS-1 832/13 ß cells exposed to normal or glucotoxic environment and their role in GSIS. Our results show that the activation of P2Y purinergic receptors by ATP or its agonist increase the insulin granules exocytosis and the reorganization of the subcortical actin network and participate in the potentiation of GSIS. In addition, their activation in INS-1832/13 ß-cells, with impaired insulin secretion following exposure to elevated glucose levels, restores GSIS competence through the distal steps of insulin exocytosis. These results are confirmed ex vivo by perifusion experiments on islets from type 2 diabetic (T2D) Goto-Kakizaki (GK) rats. Indeed, the P2Y receptor agonist restores the altered GSIS, which is normally lost in this T2D animal model. Moreover, we observed an improvement of the glucose tolerance, following the acute intraperitoneal injection of the P2Y agonist concomitantly with glucose, in diabetic GK rats. All these data provide new insights into the unprecedented therapeutic role of P2Y purinergic receptors in the pathophysiology of T2D.

Asunto(s)

Diabetes Mellitus Tipo 2 , Células Secretoras de Insulina , Islotes Pancreáticos , Actinas/metabolismo , Adenosina Trifosfato/metabolismo , Adenosina Trifosfato/farmacología , Animales , Diabetes Mellitus Tipo 2/metabolismo , Exocitosis , Glucosa/metabolismo , Glucosa/toxicidad , Insulina/metabolismo , Células Secretoras de Insulina/metabolismo , Islotes Pancreáticos/metabolismo , Ratas , Receptores Purinérgicos P2Y/metabolismo

RESUMEN

Here we aimed to unify some previous controversial reports on changes in both cannabinoid CB1 receptor (CB1R) expression and glucose metabolism in the forebrain of rodent models of diabetes. We determined how glucose metabolism and its modulation by CB1R ligands evolve in the frontal cortex of young adult male Wistar rats, in the first 8 weeks of streptozotocin-induced type-1 diabetes (T1D). We report that frontocortical CB1R protein density was biphasically altered in the first month of T1D, which was accompanied with a reduction of resting glucose uptake ex vivo in acute frontocortical slices that was normalized after eight weeks in T1D. This early reduction of glucose uptake in slices was also restored by ex vivo treatment with both the non-selective CB1R agonists, WIN55212-2 (500 nM) and the CB1R-selective agonist, ACEA (3 µM) while it was exacerbated by the CB1R-selective antagonist, O-2050 (500 nM). These results suggest a gain-of-function for the cerebrocortical CB1Rs in the control of glucose uptake in diabetes. Although insulin and IGF-1 receptor protein densities remained unaffected, phosphorylated GSKα and GSKß levels showed different profiles 2 and 8 weeks after T1D induction in the frontal cortex. Altogether, the biphasic response in frontocortical CB1R density within a month after T1D induction resolves previous controversial reports on forebrain CB1R levels in T1D rodent models. Furthermore, this study also hints that cannabinoids may be useful to alleviate impaired glucoregulation in the diabetic cortex.

Asunto(s)

Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Tipo 1/metabolismo , Lóbulo Frontal/metabolismo , Glucosa/metabolismo , Receptor Cannabinoide CB1/metabolismo , Analgésicos/farmacología , Animales , Benzoxazinas/farmacología , Diabetes Mellitus Experimental/genética , Diabetes Mellitus Tipo 1/genética , Modelos Animales de Enfermedad , Lóbulo Frontal/efectos de los fármacos , Masculino , Morfolinas/farmacología , Naftalenos/farmacología , Técnicas de Cultivo de Órganos , Ratas , Ratas Wistar , Receptor Cannabinoide CB1/agonistas , Receptor Cannabinoide CB1/antagonistas & inhibidores , Receptor Cannabinoide CB1/genética

RESUMEN

PURPOSE: To examine the effect of 3% diquafosol ophthalmic solution (DQS) on ocular surface disorders in diabetic model rats maintained in a continuous airflow condition. METHODS: Goto-Kakizaki (GK) rats, a spontaneous model of type 2 diabetes, were exposed to constant airflow for 8 weeks. After the establishment of the animal model in this environment, DQS or saline was instilled six times a day into GK rat eyes for 6 weeks. Schirmer's test was performed before and after 6-week instillations. Corneal fluorescein staining was scored at 2-, 4-, and 6-week instillations. Touch thresholds for the cornea were also determined using a Cochet-Bonnet esthesiometer before and after 6-week instillations. RESULTS: The mean Schirmer's test score after instillation of DQS was twice higher than that recorded for saline alone. DQS significantly decreased corneal staining scores at 4- and 6-week instillations. No changes in touch thresholds were observed before and after 6-week instillations. CONCLUSION: These results suggest that DQS improves corneal epithelial damage by stimulating tear secretion without influencing corneal sensation in diabetic keratopathy. Thus, DQS may have potential for treatment of diabetic patients with dry eye.

RESUMEN

High blood glucose and the consequential ischemia-reperfusion (I/R) injury damage vessels of the retina, deteriorating its function, which can be clearly visualized by electroretinography (ERG). The aim of the present study was to evaluate the possible retinoprotective effects of systemic BGP-15, an emerging drug candidate, in an insulin resistant animal model, the Goto-Kakizaki rat, and compare these results with well-known anti-diabetics such as glibenclamide, metformin, and pioglitazone, which even led to some novel conclusions about these well-known agents. Experiments were carried out on diseased animal model (Goto-Kakizaki rats). The used methods include weight measurement, glucose-related measurements-like fasting blood sugar analysis, oral glucose tolerance test, hyperinsulinemic euglycemic glucose clamp (HEGC), and calculations of different indices from HEGC results-electroretinography and Western Blot. Beside its apparent insulin sensitization, BGP-15 was also able to counteract the retina-damaging effect of Type II diabetes comparable to the aforementioned anti-diabetics. The mechanism of retinoprotective action may include sirtuin 1 (SIRT1) and matrix metalloproteinase 9 (MMP9) enzymes, as BGP-15 was able to elevate SIRT1 and decrease MMP9 expression in the eye. Based on our results, this emerging hydroximic acid derivative might be a future target of pharmacological developments as a potential drug against the harmful consequences of diabetes, such as diabetic retinopathy.

Asunto(s)

Diabetes Mellitus Tipo 2/fisiopatología , Retinopatía Diabética/prevención & control , Hipoglucemiantes/farmacología , Oximas/farmacología , Piperidinas/farmacología , Retina/efectos de los fármacos , Animales , Glucemia/metabolismo , Diabetes Mellitus Tipo 2/sangre , Modelos Animales de Enfermedad , Electrorretinografía , Gliburida/farmacología , Humanos , Ácidos Hidroxámicos/química , Ácidos Hidroxámicos/farmacología , Insulina/farmacología , Masculino , Metformina/farmacología , Estructura Molecular , Oximas/química , Pioglitazona/farmacología , Piperidinas/química , Sustancias Protectoras/química , Sustancias Protectoras/farmacología , Ratas , Ratas Wistar , Retina/fisiopatología

RESUMEN

AIMS/HYPOTHESIS: Drug and surgical-based therapies in type 2 diabetes are associated with altered gut microbiota architecture. Here we investigated the role of the gut microbiome in improved glucose homeostasis following bariatric surgery. METHODS: We carried out gut microbiome analyses in gastrectomised (by vertical sleeve gastrectomy [VSG]) rats of the Goto-Kakizaki (GK) non-obese model of spontaneously occurring type 2 diabetes, followed by physiological studies in the GK rat. RESULTS: VSG in the GK rat led to permanent improvement of glucose tolerance associated with minor changes in the gut microbiome, mostly characterised by significant enrichment of caecal Prevotella copri. Gut microbiota enrichment with P. copri in GK rats through permissive antibiotic treatment, inoculation of gut microbiota isolated from gastrectomised GK rats, and direct inoculation of P. copri, resulted in significant improvement of glucose tolerance, independent of changes in body weight. Plasma bile acids were increased in GK rats following inoculation with P. copri and P. copri-enriched microbiota from VSG-treated rats; the inoculated GK rats then showed increased liver glycogen and upregulated expression of Fxr (also known as Nr1h4), Srebf1c, Chrebp (also known as Mlxipl) and Il10 and downregulated expression of Cyp7a1. CONCLUSIONS: Our data underline the impact of intestinal P. copri on improved glucose homeostasis through enhanced bile acid metabolism and farnesoid X receptor (FXR) signalling, which may represent a promising opportunity for novel type 2 diabetes therapeutics.

Asunto(s)

Diabetes Mellitus Tipo 2/microbiología , Microbioma Gastrointestinal/fisiología , Prevotella/fisiología , Animales , Glucemia/metabolismo , Peso Corporal/fisiología , Masculino , Ratas , Transducción de Señal/fisiología

RESUMEN

Exposure to natural metabolites contributes to the risk of cardiometabolic diseases (CMDs). Through metabolome profiling, we identify the inverse correlation between serum concentrations of 4-cresol and type 2 diabetes. The chronic administration of non-toxic doses of 4-cresol in complementary preclinical models of CMD reduces adiposity, glucose intolerance, and liver triglycerides, enhances insulin secretion in vivo, stimulates islet density and size, and pancreatic ß-cell proliferation, and increases vascularization, suggesting activated islet enlargement. In vivo insulin sensitivity is not affected by 4-cresol. The incubation of mouse isolated islets with 4-cresol results in enhanced insulin secretion, insulin content, and ß-cell proliferation of a magnitude similar to that induced by GLP-1. In both CMD models and isolated islets, 4-cresol is associated with the downregulated expression of the kinase DYRK1A, which may mediate its biological effects. Our findings identify 4-cresol as an effective regulator of ß-cell function, which opens up perspectives for therapeutic applications in syndromes of insulin deficiency.

Asunto(s)

Linfocitos B/metabolismo , Glucemia/metabolismo , Cresoles/uso terapéutico , Diabetes Mellitus Tipo 2/genética , Secreción de Insulina/efectos de los fármacos , Metabolómica/métodos , Obesidad/metabolismo , Animales , Proliferación Celular , Cresoles/farmacología , Homeostasis , Humanos , Ratones , Ratas

RESUMEN

Islet inflammation is associated with defective ß cell function and mass in type 2 diabetes (T2D). Glycogen synthase kinase 3 (GSK3) has been identified as an important regulator of inflammation in different diseased conditions. However, the role of GSK3 in islet inflammation in the context of diabetes remains unexplored. In this study, we investigated the direct implication of GSK3 in islet inflammation in vitro and tested the impact of GSK3 inhibition in vivo, on the reduction of islet inflammation, and the improvement of glucose metabolism in the Goto-Kakizaki (GK) rat, a spontaneous model of T2D. GK rats were chronically treated with infra-therapeutic doses of lithium, a widely used inhibitor of GSK3. We analyzed parameters of glucose homeostasis as well as islet inflammation and fibrosis in the endocrine pancreas. Ex vivo, we tested the impact of GSK3 inhibition on the autonomous inflammatory response of non-diabetic rat and human islets, exposed to a mix of pro-inflammatory cytokines to mimic an inflammatory environment. Treatment of young GK rats with lithium prevented the development of overt diabetes. Lithium treatment resulted in reduced expression of pro-inflammatory cytokines in the islets. It decreased islet fibrosis and partially restored the glucose-induced insulin secretion in GK rats. Studies in non-diabetic human and rat islets exposed to inflammatory environment revealed the direct implication of GSK3 in the islet autonomous inflammatory response. We show for the first time, the implication of GSK3 in islet inflammation and suggest this enzyme as a viable target to treat diabetes-associated inflammation.

Asunto(s)

Diabetes Mellitus Tipo 2/metabolismo , Glucógeno Sintasa Quinasa 3/metabolismo , Islotes Pancreáticos/metabolismo , Animales , Modelos Animales de Enfermedad , Fibrosis , Glucosa/metabolismo , Humanos , Inflamación , Secreción de Insulina , Masculino , Ratas , Ratas Wistar

RESUMEN

The Goto-Kakizaki (GK) rat is a spontaneous animal model of type 2 diabetes and early stage of diabetic nephropathy. However, the pathophysiological mechanisms contributing to the progression of diabetic nephropathy in GK rats remain unclear. Kidneys from 15-week old male diabetic GK/Jcl rats and age-matched Wistar rats, which have the same genetic background as GK rats, were used. Proteomic analyses of GK and Wistar kidneys were performed using two-dimensional fluorescence difference gel electrophoresis (2D-DIGE). Differentially expressed proteins in GK rats were subjected to pathway analysis, and expression levels of hypoxia inducible factor 1α (HIF-1α) and transforming growth factor-ß1 (TGF-ß1), and fumarate accumulation in GK kidneys were examined. Azan staining and immunohistochemical staining of α-smooth muscle actin were performed in relation to fibrosis in GK kidneys. Proteomic analysis using 2D-DIGE, analysis of fumarate content, and expression analysis of HIF-1α, TGF-ß1, and α-smooth muscle actin of GK rat's kidney, suggested the mechanism of fibrosis characterized as two stages in diabetic nephropathy of GK rats. Abnormalities of glucose metabolism such as elevated levels of 2-oxoglutarate dehydrogenase and reduction of fumarate hydratase caused the accumulation of fumarate followed by the upregulation of HIF-1α and TGF-ß1 leading to fibrosis in diabetic nephropathy. Alterations in proteins involved in the tricarboxylic acid cycle are associated with fibrosis through fumarate accumulation in diabetic nephropathy of GK rats.

Asunto(s)

Nefropatías Diabéticas/metabolismo , Nefropatías Diabéticas/patología , Fumaratos/metabolismo , Riñón/patología , Animales , Ciclo del Ácido Cítrico , Regulación hacia Abajo , Fibrosis , Masculino , Ratas

RESUMEN

The function of actin is regulated by various posttranslational modifications. We have previously shown that in the kidneys of nonobese type 2 diabetes model Goto-Kakizaki rats, increased O-GlcNAcylation of ß-actin protein is observed. It has also been reported that both O-GlcNAcylation and phosphorylation occur on Ser199 of ß-actin. However, their roles are not known. To elucidate their roles in diabetic nephropathy, we examined the rat kidney for changes in O-GlcNAcylation of Ser199 (gS199)-actin and in the phosphorylation of Ser199 (pS199)-actin. Both gS199- and pS199-actin molecules had an apparent molecular weight of 40 kDa and were localized as nonfilamentous actin in both the cytoplasm and nucleus. Compared with the normal kidney, the immunostaining intensity of gS199-actin increased in podocytes of the glomeruli and in proximal tubules of the diabetic kidney, whereas that of pS199-actin did not change in podocytes but decreased in proximal tubules. We confirmed that the same results could be observed in the glomeruli of the human diabetic kidney. In podocytes of glomeruli cultured in the presence of the O-GlcNAcase inhibitor Thiamet G, increased O-GlcNAcylation was accompanied by a concomitant decrease in the amount of filamentous actin and in morphological changes. Our present results demonstrate that dysregulation of O-GlcNAcylation and phosphorylation of Ser199 occurred in diabetes, which may contribute partially to the causes of the morphological changes in the glomeruli and tubules. gS199- and pS199-actin will thus be useful for the pathological evaluation of diabetic nephropathy.

Asunto(s)

Actinas/metabolismo , Nefropatías Diabéticas/metabolismo , Acilación , Secuencia de Aminoácidos , Animales , Diabetes Mellitus Tipo 2 , Nefropatías Diabéticas/patología , Humanos , Riñón/metabolismo , Riñón/patología , Masculino , Modelos Moleculares , Fosforilación , Podocitos/metabolismo , Conformación Proteica , Ratas , Ratas Endogámicas

RESUMEN

Diabetic cardiomyopathy, especially myocardial ischemia reperfusion (I/R) injury, is a major cause of morbidity and mortality in type 2 diabetic patients. The increasing of basal p38 MAP Kinase (p38 MAPK) activation is a major factor that aggravates cardiac death on diabetic cardiomyopathy. In addition, metformin also shows cardio-protective effects on myocardial ischemia/reperfusion injury. In this study, we investigated the effect of the combination between metformin and p38 MAPK inhibitor (SB203580) in diabetic rats subjected to I/R injury. H9c2 cells were induced into a hyperglycemic condition and treated with metformin, SB203580 or the combination of metformin and SB203580. In addition, cells in both the presence and absence of drug treatment were subjected to simulated ischemia/reperfusion injury. Cell viability and cellular reactive oxygen species (ROS) were determined. Moreover, the Goto-Kakizaki (GK) rats were treated with metformin, SB203580, and the combination of metformin and SB203580 for 4 weeks. Diabetic parameters and cardiac functions were assessed. Finally, rat hearts were induced ischemia/reperfusion injury for the purpose of infarct size analysis and determination of signal transduction. A high-glucose condition did not reduce cell viability but significantly increased ROS production and significantly decreased cell viability after induced sI/R. Treatment using drugs was shown to reduce ROS generation and cardiac cell death. The GK rats displayed diabetic phenotype by increasing diabetic parameters and these parameters were significantly decreased when treated with drugs. Treatment with metformin or SB203580 could significantly reduce the infarct size. Interestingly, the combination of metformin and SB203580 could enhance cardio-protective ability. Myocardial I/R injury significantly increased p38 MAPK phosphorylation, Bax/Bcl-2 ratio and caspase-3 level. Treatment with drugs significantly decreased the p38 MAPK phosphorylation, Bax/Bcl-2 ratio, caspase-3 level and increased Akt phosphorylation. In conclusion, using the combination of metformin and SB203580 shows positive cardio-protective effects on diabetic ischemic cardiomyopathy.

RESUMEN

Estrogen deprivation accelerates bone resorption, leading to imbalance of bone remodeling and osteoporosis in postmenopausal women. In the elderly, type 2 diabetes mellitus (T2DM) frequently coexists as an independent factor of bone loss. However, little is known about the skeletal changes in a combined condition of estrogen deficiency and T2DM. Herein, we performed ovariectomy (OVX) in nonobese Goto-Kakizaki (GK) T2DM rats to examine changes associated with calcium and phosphate metabolism and bone microstructures and strength. As expected, wild-type (WT) rats subjected to ovariectomy (OVX-WT) had low trabecular bone volume and serum calcium with increased dynamic histomorphometric and serum bone markers, consistent with the high turnover state. T2DM in GK rats also led to low trabecular volume and serum calcium. However, the dynamic histomorphometric markers of bone remodeling were unaffected in these GK rats, indicating the distinct mechanism of T2DM-induced bone loss. Interestingly, OVX-GK rats were found to have anomalous and unique changes in bone turnover-related parameters, i.e., decreased osteoblast and osteoclast surfaces with lower COOH-terminal telopeptide of type I collagen levels compared with OVX-WT rats. Furthermore, the levels of calciotropic hormones, i.e., parathyroid hormone and 1,25(OH)2D3, were significantly decreased in OVX-GK rats. Although the OVX-induced bone loss did not further worsen in GK rats, a three-point bending test indicated that OVX-GK bones exhibited a decrease in bone elasticity. In conclusion, T2DM and estrogen deficiency both led to microstructural bone loss, the appearance of which did not differ from each factor alone. Nevertheless, the combination worsened the integrity and suppressed the turnover, which might eventually result in adynamic bone disease.

Asunto(s)

Enfermedades Óseas Metabólicas/patología , Diabetes Mellitus Tipo 2/patología , Estrógenos/deficiencia , Osteoporosis/patología , Ovariectomía , Animales , Biomarcadores/sangre , Densidad Ósea , Enfermedades Óseas Metabólicas/metabolismo , Remodelación Ósea , Calcitriol/sangre , Calcio/sangre , Colágeno Tipo I/biosíntesis , Elasticidad , Femenino , Osteoblastos/metabolismo , Osteoclastos/metabolismo , Hormona Paratiroidea/sangre , Ratas , Ratas Wistar

RESUMEN

To define renal molecular mechanisms that are affected by permanent hyperglycaemia and might promote phenotypes relevant to diabetic nephropathy, we carried out linkage analysis of genome-wide gene transcription in the kidneys of F2 offspring from the Goto-Kakizaki (GK) rat model of type 2 diabetes and normoglycaemic Brown Norway (BN) rats. We mapped 2526 statistically significant expression quantitative trait loci (eQTLs) in the cross. More than 40% of eQTLs mapped in the close vicinity of the linked transcripts, underlying possible cis-regulatory mechanisms of gene expression. We identified eQTL hotspots on chromosomes 5 and 9 regulating the expression of 80-165 genes, sex or cross direction effects, and enriched metabolic and immunological processes by segregating GK alleles. Comparative analysis with adipose tissue eQTLs in the same cross showed that 496 eQTLs, in addition to the top enriched biological pathways, are conserved in the two tissues. Extensive similarities in eQTLs mapped in the GK rat and in the spontaneously hypertensive rat (SHR) suggest a common aetiology of disease phenotypes common to the two strains, including insulin resistance, which is a prominent pathophysiological feature in both GK rats and SHRs. Our data shed light on shared and tissue-specific molecular mechanisms that might underlie aetiological aspects of insulin resistance in the context of spontaneously occurring hyperglycaemia and hypertension.

Asunto(s)

Tejido Adiposo/metabolismo , Modelos Animales de Enfermedad , Resistencia a la Insulina/genética , Riñón/metabolismo , Transcriptoma , Animales , Mapeo Cromosómico , Diabetes Mellitus Tipo 2/genética , Predisposición Genética a la Enfermedad , Sitios de Carácter Cuantitativo , Ratas , Ratas Endogámicas BN , Ratas Endogámicas SHR

RESUMEN

Obesity, a sedentary lifestyle and type 2 diabetes are intricately linked conditions contributing to reduced exercise tolerance, significant morbidity, and premature deaths. It is unknown whether the reported exercise intolerance associated with type 2 diabetes is a direct result of the hyperglycemia, the impact of a relatively sedentary lifestyle, or increased adiposity. We hypothesize that obesity and inactivity, not hyperglycemia, cause exercise intolerance in individuals with type 2 diabetes. An analysis of the literature and results from the Goto-Kakizaki (GK) rat model of type 2 diabetes strongly support this hypothesis. GK rats were not sedentary or obese when compared with Wistar control rats and did not have exercise intolerance. Specifically, despite being hyperglycemic, GK rats demonstrated a longer treadmill run time to exhaustion (150.6 ±â€¯9.0 vs. 77.2 ±â€¯12.9 min), further distance run (1506 ±â€¯90 vs. 772 ±â€¯129 m), more work performed per gram muscle (44.0 ±â€¯2.8 vs. 21.9 ±â€¯3.8 kg*m/g) and a small increase in total vertical work performed when accounting for body mass (116.8 ±â€¯6.3 versus 98.9 ±â€¯15.2 kg*m). These results document preserved exercise tolerance in the non-obese, non-sedentary GK rat supporting the hypothesis that the reported exercise intolerance in models of type 2 diabetes is dependent on obesity and inactivity. Solving the obesity and inactivity versus hyperglycemia causality dilemma is important in understanding the development of type 2 diabetes and implications for future pharmacological and life style interventions.

Asunto(s)

Diabetes Mellitus Tipo 2/complicaciones , Tolerancia al Ejercicio , Hiperglucemia/complicaciones , Obesidad/complicaciones , Condicionamiento Físico Animal , Animales , Peso Corporal , Enfermedades Cardiovasculares , Diabetes Mellitus Tipo 2/fisiopatología , Modelos Animales de Enfermedad , Humanos , Hiperglucemia/fisiopatología , Estilo de Vida , Masculino , Actividad Motora , Obesidad/fisiopatología , Estrés Oxidativo , Ratas , Ratas Wistar , Factores de Riesgo

RESUMEN

The Goto-Kakizaki (GK) rat is a model of type 2 diabetes mellitus, produced originally by selective inbreeding for a hyperglycemic trait. These rats are characterized as having insulin resistance and an insulin secretory defect. Pancreatic islets from these mice show abnormal morphology in the distribution of glucagon-secreting α cells and insulin-secreting ß cells, which may affect paracrine functions involved in the secretory response. This chapter describes the characterization of GK rat islets using immunofluorescence microscopy and Western blot analyses to demonstrate the effects on islet architecture and how this translates to changes in expression of predominant islet proteins.

Asunto(s)

Diabetes Mellitus Tipo 2/patología , Hiperglucemia/patología , Células Secretoras de Insulina/ultraestructura , Biología Molecular/métodos , Animales , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/metabolismo , Modelos Animales de Enfermedad , Glucosa/metabolismo , Humanos , Hiperglucemia/genética , Hiperglucemia/metabolismo , Resistencia a la Insulina/genética , Secreción de Insulina/genética , Células Secretoras de Insulina/patología , Ratas

RESUMEN

Diabetes mellitus is a major global health disorder and, currently, over 450 million people have diabetes with 90% suffering from type 2 diabetes. Left untreated, diabetes may lead to cardiovascular diseases which are a leading cause of death in diabetic patients. Calcium is the trigger and regulator of cardiac muscle contraction and derangement in cellular Ca2+ homeostasis, which can result in heart failure and sudden cardiac death. It is of paramount importance to investigate the regional involvement of Ca2+ in diabetes-induced cardiomyopathy. Therefore, the aim of this study was to investigate the voltage dependence of the Ca2+ transients in endocardial (ENDO) and epicardial (EPI) myocytes from the left ventricle of the Goto-Kakizaki (GK) rats, an experimental model of type 2 diabetes mellitus. Simultaneous measurement of L-type Ca2+ currents and Ca2+ transients was performed by whole-cell patch clamp techniques. GK rats displayed significantly increased heart weight, heart weight/body weight ratio, and non-fasting and fasting blood glucose compared to controls (CON). Although the voltage dependence of L-type Ca2+ current was unaltered, the voltage dependence of the Ca2+ transients was reduced to similar extents in EPI-GK and ENDO-GK compared to EPI-CON and ENDO-CON myocytes. TPK L-type Ca2+ current and Ca2+ transient were unaltered. THALF decay of L-type Ca2+ current was unaltered; however, THALF decay of the Ca2+ transient was shortened in ENDO and EPI myocytes from GK compared to CON rat hearts. In conclusion, the amplitude of L-type Ca2+ current was unaltered; however, the voltage dependence of the Ca2+ transient was reduced to similar extents in EPI and ENDO myocytes from GK rats compared to their respective controls, suggesting the possibility of dysfunctional sarcoplasmic reticulum Ca2+ transport in the GK diabetic rat hearts.

Asunto(s)

Señalización del Calcio , Calcio/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Cardiomiopatías Diabéticas/metabolismo , Endocardio/metabolismo , Miocitos Cardíacos/metabolismo , Pericardio/metabolismo , Animales , Canales de Calcio Tipo L/metabolismo , Diabetes Mellitus Tipo 2/patología , Cardiomiopatías Diabéticas/patología , Endocardio/patología , Ventrículos Cardíacos/metabolismo , Ventrículos Cardíacos/patología , Miocitos Cardíacos/patología , Pericardio/patología , Ratas

RESUMEN

The GLIS family zinc finger 3 isoform (GLIS3) is a risk gene for Type 1 and Type 2 diabetes, glaucoma and Alzheimer's disease endophenotype. We identified GLIS3 binding sites in insulin secreting cells (INS1) (FDR q<0.05; enrichment range 1.40-9.11 fold) sharing the motif wrGTTCCCArTAGs, which were enriched in genes involved in neuronal function and autophagy and in risk genes for metabolic and neuro-behavioural diseases. We confirmed experimentally Glis3-mediated regulation of the expression of genes involved in autophagy and neuron function in INS1 and neuronal PC12 cells. Naturally-occurring coding polymorphisms in Glis3 in the Goto-Kakizaki rat model of type 2 diabetes were associated with increased insulin production in vitro and in vivo, suggestive alteration of autophagy in PC12 and INS1 and abnormal neurogenesis in hippocampus neurons. Our results support biological pleiotropy of GLIS3 in pathologies affecting ß-cells and neurons and underline the existence of trans­nosology pathways in diabetes and its co-morbidities.

Asunto(s)

Células Secretoras de Insulina/metabolismo , Neuronas/metabolismo , Factores de Transcripción/metabolismo , Animales , Autofagia , Sitios de Unión , Línea Celular Tumoral , Células Cultivadas , Diabetes Mellitus Experimental/genética , Diabetes Mellitus Experimental/metabolismo , Hipocampo/citología , Masculino , Neurogénesis , Neuronas/citología , Células PC12 , Polimorfismo Genético , Unión Proteica , Ratas , Ratas Sprague-Dawley , Factores de Transcripción/química , Factores de Transcripción/genética

RESUMEN

BACKGROUND: This study aimed to investigate the influence of new biliopancreatic diversion (NBPD) and duodenal-jejunal bypass (DJB) surgery on blood glucose, lipids, gastrointestinal hormones, and insulin in Goto-Kakizaki (GK) rats, an animal model for type 2 diabetes, in order to elucidate the mechanisms underlying the therapeutic effect of these types of surgery on this clinical condition. METHODS: Thirty 30 male GK rats (SPF) aged 12 weeks were randomly assigned into three groups (n = 10 per group): sham group, NBPD group, and DJB group. Body weight, random plasma glucose, fasting plasma glucose (FPG), oral glucose tolerance (OGT), blood lipids, plasma insulin, glucagon like peptide-1 (GLP-1), and gastric inhibitory polypeptide (GIP) were measured before and after surgery. RESULTS: NBPD surgery improved glucose tolerance, decreased fasting free fatty acids, triglycerides, and cholesterol. It also increased fasting and postprandial GIP, but caused no change in GLP-1. DJB surgery produced results similar to NBPD surgery except for causing a decrease in postprandial GLP-1 and insulin, and a larger increase in fasting GIP. CONCLUSIONS: Moving the biliopancreatic duct outlet to the mid-jejunum (NBPD surgery) improves glucose tolerance and increases GIP, but does not change GLP-1. Adding duodenal bypass (DJB surgery) increases fasting GIP and decreases postprandial GLP-1.

Asunto(s)

Desviación Biliopancreática/métodos , Glucemia/metabolismo , Diabetes Mellitus Experimental/cirugía , Diabetes Mellitus Tipo 2/cirugía , Lípidos/sangre , Animales , Glucemia/análisis , Diabetes Mellitus Experimental/sangre , Duodeno/cirugía , Derivación Gástrica/métodos , Polipéptido Inhibidor Gástrico/sangre , Péptido 1 Similar al Glucagón/sangre , Prueba de Tolerancia a la Glucosa , Insulina/sangre , Resistencia a la Insulina , Yeyuno/cirugía , Metabolismo de los Lípidos/fisiología , Masculino , Ratas

RESUMEN

We previously reported that rice endosperm protein (REP) has renoprotective effects in Goto-Kakizaki rats, a non-obese diabetic model. However, whether these effects occur in obese diabetes remains unclear. This study aimed to clarify the effects of REP on obese diabetes, especially on fatty liver and diabetic nephropathy, using the obese diabetic model Zucker diabetic fatty (ZDF) rats. In total, 7-week-old male ZDF rats were fed diets containing 20 % REP or casein (C) for 8 weeks. Changes in fasting blood glucose levels and urinary markers were monitored during the experimental period. Hepatic lipids and metabolites were measured and renal glomeruli were observed morphologically. HbA1c levels were significantly lower in rats fed REP, compared with C (P<0·05). Compared with C in the liver, REP prevented lipid accumulation (total lipid, TAG and total cholesterol, P<0·01). Liver metabolome analysis indicated that levels of metabolites associated with glycolysis, the pentose phosphate pathway and carnitine metabolism were significantly greater in the REP group than in the C group (P<0·05), suggesting activation of both glucose catabolism and fatty acid oxidation. The metabolite increases promoted by REP may contribute to suppression of liver lipid accumulation. Urinary excretion of albumin and N-acetyl-ß-d-glucosaminidase was significantly reduced in rats fed REP for 8 weeks (P<0·01). In addition, there was a distinct suppression of mesangial matrix expansion and glomerular hypertrophy in response to REP (P<0·01). Thus, REP had preventive effects on obese diabetes, fatty liver and diabetic nephropathy.

Asunto(s)

Diabetes Mellitus Tipo 2/dietoterapia , Nefropatías Diabéticas/dietoterapia , Dieta Vegetariana , Endospermo/química , Enfermedad del Hígado Graso no Alcohólico/dietoterapia , Oryza/química , Proteínas de Vegetales Comestibles/uso terapéutico , Animales , Biomarcadores/sangre , Biomarcadores/metabolismo , Biomarcadores/orina , Errores Innatos del Metabolismo de los Carbohidratos/prevención & control , Diabetes Mellitus Tipo 2/complicaciones , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/patología , Nefropatías Diabéticas/complicaciones , Nefropatías Diabéticas/metabolismo , Nefropatías Diabéticas/fisiopatología , Dieta Vegetariana/efectos adversos , Progresión de la Enfermedad , Metabolismo Energético , Glicerol Quinasa/deficiencia , Hiperfosfatemia/etiología , Hiperfosfatemia/prevención & control , Insuficiencia Corticosuprarrenal Familiar , Glomérulos Renales/patología , Glomérulos Renales/fisiopatología , Metabolismo de los Lípidos , Hígado/metabolismo , Hígado/patología , Masculino , Enfermedad del Hígado Graso no Alcohólico/complicaciones , Enfermedad del Hígado Graso no Alcohólico/metabolismo , Enfermedad del Hígado Graso no Alcohólico/fisiopatología , Obesidad/complicaciones , Tamaño de los Órganos , Proteínas de Vegetales Comestibles/efectos adversos , Ratas Zucker , Insuficiencia Renal Crónica/etiología , Insuficiencia Renal Crónica/prevención & control , Aumento de Peso