Spontaneously Diabetic Torii Fatty Rats Research Articles

Protective Effect of Pemafibrate Treatment against Diabetic Retinopathy in Spontaneously Diabetic Torii Fatty Rats.

Diabetic retinopathy (DR) can cause visual impairment and blindness, and the increasing global prevalence of diabetes underscores the need for effective therapies to prevent and treat DR. Therefore, this study aimed to evaluate the protective effect of pemafibrate treatment against DR, using a Spontaneously Diabetic Torii (SDT) fatty rat model of obese type 2 diabetes. SDT fatty rats were fed either a diet supplemented with pemafibrate (0.3 mg/kg/day) for 16 weeks, starting at 8 weeks of age (Pf SDT fatty: study group), or normal chow (SDT fatty: controls). Normal chow was provided to Sprague-Dawley (SD) rats (SD: normal controls). Electroretinography (ERG) was performed at 8 and 24 weeks of age to evaluate the retinal neural function. After sacrifice, retinal thickness, number of retinal folds, and choroidal thickness were evaluated, and immunostaining was performed for aquaporin-4 (AQP4). No significant differences were noted in food consumption, body weight, or blood glucose level after pemafibrate administration. Triglyceride levels were reduced, and high-density lipoprotein cholesterol levels were increased. Extension of oscillatory potential (OP)1 and OP3 waves on ERG was suppressed in the Pf SDT fatty group. Retinal thickness at 1,500 microns from the optic disc improved in the Pf SDT fatty group. No significant improvements were noted in choroidal thickness or number of retinal folds. Quantitative analyses showed that AQP4-positive regions in the retinas were significantly larger in the Pf SDT fatty group than in the SDT fatty group. The findings suggest that pemafibrate treatment can exert protective effects against DR.

Phosphorylation of αB-Crystallin Involves Interleukin-1β-Mediated Intracellular Retention in Retinal Müller Cells: A New Mechanism Underlying Fibrovascular Membrane Formation.

Chronic inflammation plays a pivotal role in the pathology of proliferative diabetic retinopathy (PDR), in which biological alterations of retinal glial cells are one of the key elements. The phosphorylation of αB-crystallin/CRYAB modulates its molecular dynamics and chaperone activity, and attenuates αB-crystallin secretion via exosomes. In this study, we investigated the effect of phosphorylated αB-crystallin in retinal Müller cells on diabetic mimicking conditions, including interleukin (IL)-1β stimuli. Human retinal Müller cells (MIO-M1) were used to examine gene and protein expressions with real-time quantitative PCR, enzyme linked immunosorbent assay (ELISA), and immunoblot analyses. Cell apoptosis was assessed by Caspase-3/7 assay and TdT-mediated dUTP nick-end labeling staining. Retinal tissues isolated from the Spontaneously Diabetic Torii (SDT) fatty rat, a type 2 diabetic animal model with obesity, and fibrovascular membranes from patients with PDR were examined by double-staining immunofluorescence. CRYAB mRNA was downregulated in MIO-M1 cells with the addition of 10ng/mL IL-1β; however, intracellular αB-crystallin protein levels were maintained. The αB-crystallin serine 59 (Ser59) residue was phosphorylated with IL-1β application in MIO-M1 cells. Cell apoptosis in MIO-M1 cells was induced by CRYAB knockdown. Immunoreactivity for Ser59-phosphorylated αB-crystallin and glial fibrillary acidic protein was colocalized in glial cells of SDT fatty rats and fibrovascular membranes. The Ser59 phosphorylation of αB-crystallin was modulated by IL-1β in Müller cells under diabetic mimicking inflammatory conditions, suggesting that αB-crystallin contributes to the pathogenesis of PDR through an anti-apoptotic effect.

Mechanism for exercise-mediated prevention against muscle wasting on extensor digitorum longus muscle in Spontaneously Diabetic Torii fatty rats

We previously reported the significant increase in limb muscle strength and cross-sectional area of the type IIb muscle fibers in the extensor digitorum longus (EDL) muscle in a type 2 diabetic animal model, with Spontaneously Diabetic Torii (SDT) fatty rats (n = 6) undergoing regular treadmill exercise from 8 to 16 weeks of age compared with sedentary SDT fatty rats (n = 6). This study investigated the mechanism by which exercise training prevented skeletal muscle wasting in the EDL muscle of the SDT fatty rats. The endurance exercise for 8 weeks downregulated the expression of muscle RING-finger protein-1 (an E3 ubiquitin ligase) and upregulated the expression of CD31, insulin receptor substrate-2, and phosphorylated endothelial nitric oxide synthase in the EDL muscle of 16-week-old SDT fatty rats.Endurance exercise training might reduce muscle wasting by preventing muscle degradation and increasing the angiogenic response in the EDL muscle in type 2 diabetes.

PS-B08-7: L-CARNITINE AMELIORATES DIABETIC KIDNEY DISEASE BY ALLEVIATING MITOCHONDRIAL ABNORMALITY IN SDT-FATTY RATS

Background and Aims: Abnormal fatty acid metabolism is associated with the progression of diabetic kidney disease (DKD). Carnitine plays a central role in β;-oxidation and energy production by transporting long-chain fatty acids from the cytoplasm to the mitochondria. Recently, we found that significant ectopic fat was accumulated in the kidney tissue in DKD patients compared with those in minimal change kidney disease patients. Juvenile visceral steatosis (jvs) mice, described as an animal model for systemic carnitine deficiency, introduce a marked ectopic fat accumulation in the kidney. These findings suggest that abnormal carnitine dynamics in DKD cause ectopic fat accumulation due to abnormality of the fatty acid metabolism. However, the association between abnormalities of carnitine metabolism and the progression of DKD is unknown. Method: Spontaneously Diabetic Torii (SDT) fatty rat, an obese type 2 diabetic model was used. Unilateral nephrectomy was performed and 0.3% salt water was administered at 6 weeks of age, and created a renal dysfunction model in SDT fatty rat (DKD model). Age-matched male Sprague-Dawley (SD) rat was used as a control. Experiment 1: We compared 3 groups; SD rats (n = 8), SDT fatty rats (n = 8), DKD rats (n = 8). Experiment 2: We compared 3 groups; SD rats with sham operation (n = 8), DKD rats (n = 7), DKD rats treated with L-carnitine administration (0.75% L-carnitine diet) for 10 weeks (n = 6). All rats were sacrificed at 17 weeks old. Carnitine was measured by the enzyme cycling method. Acylcarnitine was analyzed by the tandem-mass spectrometry. Results: Plasma and renal free carnitine levels and short/middle-long chain acylcarnitine ratio were significantly decreased in DKD rats compared with those in SD and SDT fatty rats. The renal expression levels of organic cation / carnitine transporter 2 (OCTN2), carnitine palmitoyl transferase 1a (CPT1a), CPT2 and carnitine acetyltransferase (CrAT) were significantly decreased in DKD rats compared with those in SD and SDT fatty rats. Similarly, peroxisome proliferator-activated receptor γ co-activator 1α (PGC1α) activity was decreased in DKD rats. L-carnitine administration significantly improved renal function, urinary albumin excretion, interstitial fibrosis and renal ectopic fat accumulation in DKD model rats. L-carnitine administration ameliorated the decrease of renal OCTN2, CPT1a, CPT2 and CrAT protein expression, and significantly improved PGC1α activity in DKD model rats. Furthermore, L-carnitine administration mitigated lipid peroxidation and mitochondrial dysfunction in DKD rats. Conclusion: L-carnitine administration might be a promising therapeutic strategy for improving renal function by alleviating mitochondrial dysfunction in DKD rat model.

Beneficial effects of SGLT2 inhibitor on metabolic inflexibility and visceral fat amount in animal model of obese type 2 diabetes

BackgroundObesity and type 2 diabetes mellitus (T2DM) are often accompanied with a disrupted diurnal rhythm of eating and sustained anabolic state, leading to metabolic inflexibility. In the present study, we plan to investigate effects of a sodium glucose co-transporter 2 (SGLT2) inhibitor, canagliflozin (CANA), on such a metabolic inflexibility, especially on fat metabolism, in the obese type 2 diabetic rats. Materials and methodsFive-week-old male SDT (Spontaneously Diabetic Torii) fatty rats as a model of obesity and T2DM and Sprague-Dawley (SD) rats were treated by either CANA (10 mg/kg) or saline (vehicle) orally for 14 days. Then, after the measurement of respiratory quotient (RQ) and visceral and subcutaneous fat volumes, rats were euthanized and blood and tissue samples were collected. ResultsThe treatment by CANA significantly enhanced β-ketone concentration in the blood during light period in the SDT fatty rats with no effect on blood glucose concentration. The CANA treatment significantly reduced visceral fat volume in the SDT fatty rats. A diurnal rhythm of RQ was severely disrupted and persistently high throughout the day in the vehicle-treated SDT fatty rats. By the administration of CANA clearly restored the disrupted diurnal rhythm of RQ with a revival of the nadir during light period. Quantitative real-time RT-PCR revealed a significant increase of AMP-activated protein kinase and decrease of acetyl-CoA carboxylase-1 expression in the liver, and a significant increase of hormone sensitive lipase and uncoupling protein-2 expression in the white adipose tissue by the treatment of CANA in the SDT fatty rats. ConclusionCANA as a SGLT2i reduced visceral fat amount via the enhancement of fat oxidation during the light period, leading to an amelioration of metabolic inflexibility in an obese diabetic model. A novel mechanism of CANA prompts the possibility that this new class of anti-diabetic agent could be a promising anti-obesity agent as well.

Glucagon-like peptide-1 receptor agonist, liraglutide, attenuated retinal thickening in spontaneously diabetic Torii fatty rats.

BackgroundThis study aims to investigate the effect of the glucagon-like peptide-1 (GLP-1) receptor agonist (GLP-1RA) liraglutide on retinal pathological findings as compared with insulin and hydralazine using an animal model of type 2 diabetes with obesity, hypertension, and hyperlipidemia.MethodsMale spontaneously diabetic Torii (SDT) fatty rats at 8 weeks of age were randomly assigned to three groups: the liraglutide group (SDT-lira, n = 6) received a subcutaneous injection of liraglutide from the age of 8 to 16 weeks, the SDT-ins-hyd group (n = 6) was provided both insulin against hyperglycemia and hydralazine against hypertension to match levels of both blood glucose and blood pressure to those of the liraglutide group, and the control group of SDT fatty rats (SDT-vehicle, n = 7) and a nondiabetic control group of Sprague–Dawley rats (SD, n = 7) were injected with vehicle only. Both eyeballs of all groups were collected at the age of 16 weeks.ResultsRetinal thickness, which was found in the SDT-vehicle group, was significantly prevented to similar levels in both the SDT-lira and SDT-ins-hyd groups. Immunohistological analysis revealed that GLP-1 receptor was not expressed in the retina of all rats. The ocular protein expression of monocyte chemoattractant protein-1, which causes a proinflammatory situation, was significantly upregulated in all SDT fatty rats as compared to SD rats, but the expression levels were similar between all SDT fatty rats. With regard to neovascularization in the eyes, there were no significant differences in protein expressions of vascular endothelial growth factor, CD31, or endothelial nitric oxide synthase in all rats.ConclusionsThe present study indicates that liraglutide prevents retinal thickening, dependent on blood glucose and blood pressure levels in SDT fatty rats without ocular neovascularization. However, the effects did not improve the ocular proinflammatory state.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12886-022-02413-y.

MO617: Liraglutide Improves Both Diabetic Nephropathy and Cardiomyopathy in the SDT Fatty Rat, A Cardiorenal Model of Type 2 Diabetes

Abstract BACKGROUND AND AIMS The Glucagon-like peptide 1 (GLP-1) receptor agonist liraglutide (LIRA) has cardioprotective effects and may reduce the development of kidney disease in type 2 diabetic patients. We here evaluated the effects of LIRA on both kidney and heart function in the Spontaneously Diabetic Torii (SDT) fatty rat, a type 2 diabetic cardiorenal model. METHOD SDT fatty male rats were treated subcutaneously with vehicle or LIRA 0.4 mg/kg QD for 10 weeks. To measure the effects of LIRA on glomerular hyperfiltration, rats were injected with FITC-sinistrin to measure glomerular filtration rate (GFR) at 4 weeks of treatment. At 5 weeks of treatment, rats underwent unilateral nephrectomy and were put on a 0.3% salt diet to induce a GFR decline. GFR was then measured at 10 weeks of treatment, before hemodynamics measurement and echocardiography. RESULTS Compared with vehicle, LIRA induced significant body weight loss, as well as blood glucose levels reduction by up to ∼20%. During the hyperfiltration phase, LIRA attenuated hyperfiltration, with a 19% lower GFR versus vehicle (P < 0.05). In vehicle-treated animals, unilateral nephrectomy and 0.3% salt diet induced a major reduction (−56%) in GFR, as expected. After 10 weeks of treatment, LIRA markedly attenuated this GFR decline (vehicle: 9.3 ± 0.5 mL/min/kg; LIRA: 13.3 ± 0.9 mL/min/kg, P < 0.001 versus vehicle). Compared with vehicle, LIRA also lowered urine albumin-to-creatinine ratio both in the hyperfiltration and GFR decline phases, and significantly reduced kidney inflammation and fibrosis histology scores. LIRA showed significant reduction in cardiac hypertrophy, as well as both arterial and left ventricle end-systolic pressures. Moreover, LIRA normalized the diastolic dysfunction with preserved ejection fraction observed in SDT fatty rats (P < 0.001 versus vehicle). CONCLUSION In the SDT fatty rat, LIRA shows significant benefits by reducing renal hyperfiltration, preventing GFR decline, and improving cardiac hypertrophy, blood pressure and diastolic dysfunction. This preclinical model will be useful to evaluate drugs targeting the cardiorenal axis in type 2 diabetes.

Salt loading with unilateral nephrectomy accelerates decline in glomerular filtration rate in the hypertensive, obese, type 2 diabetic SDT fatty rat model of diabetic kidney disease.

For the evaluation of novel therapeutic agents for diabetic kidney disease (DKD), it is desirable to examine their efficacy in animal models by using the glomerular filtration rate (GFR) as an index. For this purpose, animal models that demonstrate a short-term GFR decline because of disease progression are required. Therefore, we aimed to develop such an animal model of DKD by using obese type 2 diabetic spontaneously diabetic Torii (SDT) fatty rats treated with salt loading by drinking water containing sodium chloride with or without unilateral nephrectomy. As a result, we have found that 0.3% salt loading with unilateral nephrectomy or 0.8% salt loading alone caused a rapid GFR decline, hypertension and rapid development of tubulointerstitial fibrosis. Moreover, the addition of losartan to a mixed diet suppressed the GFR decline in SDT fatty rats treated with 0.3% salt loading with unilateral nephrectomy. These results suggest that the model of SDT fatty rats treated with 0.3% salt loading and unilateral nephrectomy could be used as a hypertensive DKD model for evaluating therapeutic agents based on suppression of GFR decline.

POS-331 L-carnitine ameliorates diabetic kidney disease by alleviating mitochondrial abnormality and fatty acid accumulation in SDT-fatty rats

Abnormal fatty acid metabolism is associated with the progression of diabetic kidney disease (DKD). Carnitine plays a central role in fatty acid β-oxidation and energy production by transporting long-chain fatty acids from the cytoplasm to the mitochondria. Recently, we found that significant ectopic fat was accumulated in the kidney tissue in DKD patients compared with those in minimal change kidney disease patients independent of proteinuria levels, suggesting the abnormal carnitine dynamics in DKD. Juvenile visceral steatosis (jvs) mice, described as an animal model for systemic carnitine deficiency caused by a mutation in slc22a5 gene, introduce a marked ectopic fat accumulation in the kidney. These findings suggest that abnormal carnitine dynamics in DKD cause ectopic fat accumulation due to abnormality of the fatty acid metabolism. However, the association between abnormalities of carnitine metabolism and the progression of DKD is unknown. Therefore, we investigated the kinetics of carnitine and the effect of L-carnitine therapy in type 2 DKD model rats. Spontaneously Diabetic Torii (SDT) fatty rat, an obese type 2 diabetic model was used. Unilateral nephrectomy was performed and 0.3% salt water was administered at 6 weeks of age, and created a renal dysfunction model in SDT fatty rat (DKD model). Age-matched male Sprague-Dawley (SD) rat was used as a control. Experiment 1: We compared 3 groups; ①SD rats (n=8) ②SDT fatty rats (n=8) ③DKD rats (n=8). Experiment 2: We compared 3 groups; ①SD rats with sham operation (n=8) ②DKD rats (n=7) ③DKD rats treated with L-carnitine administration (0.75% L-carnitine diet) for 10 weeks (n=6). All rats were sacrificed at 17 weeks old. Carnitine was measured by the enzyme cycling method. Acylcarnitine was analyzed by the tandem-mass spectrometry. Plasma and renal free carnitine levels were significantly decreased and long-chain acylcarnitine levels were significantly increased in DKD rats compared with those in SD and SDT fatty rats. The renal expression levels of organic cation / carnitine transporter 2 (OCTN2), carnitine palmitoyl transferase 1a (CPT1a), CPT2 and carnitine acetyltransferase (CrAT) were significantly decreased in DKD rats compared with those in SD and SDT fatty rats. Similarly, acetyl-CoA carboxylase (ACC) activity was significantly increased and peroxisome proliferator-activated receptor γ co-activator 1α (PGC1α) and peroxisome proliferator-activated receptor α (PPARα) activity were decreased in DKD rats. Further, marked ectopic fat accumulation in the renal tubules and glomeruli in DKD model rats was observed. L-carnitine administration significantly improved renal function, urinary albumin excretion, interstitial fibrosis and renal ectopic fat accumulation in DKD model rats. L-carnitine administration ameliorated the decrease of renal OCTN2, CPT1a, CPT2 and CrAT protein expression, and significantly improved ACC, PGC1α, and PPARα activity in DKD model rats. Furthermore, L-carnitine administration mitigated lipid peroxidation and mitochondrial dysfunction in DKD rats Abnormal carnitine kinetics and dynamics might play an important role in the progression of DKD. L-carnitine administration might be a promising therapeutic strategy for improving renal function by alleviating mitochondrial dysfunction in DKD rat model.

Pathophysiological features in the brains of female Spontaneously Diabetic Torii (SDT) fatty rats.

Diabetes mellitus (DM) and obesity are associated with neurodegenerative diseases such as Alzheimer’s disease and psychiatric disorders such as major depression. In this study, we investigated pathophysiological changes in the brains of female Spontaneously Diabetic Torii (SDT) fatty rats with diabetes and obesity. Brains of Sprague-Dawley (SD), SDT and SDT fatty rats were collected at 58 weeks of age. The parietal cortical thickness was measured and the number of pyramidal cells in the hippocampal cornu ammonis 1 and 3 (CA1 and CA3) and the number of granule cells in the dentate gyrus (DG) regions were counted. The area of glial fibrillary acidic protein (GFAP) positivity in CA1, CA3 and DG regions were measured. The parietal cortical thickness and the number of cells in CA3 and DG regions of SDT and SDT fatty rats did not show obvious changes. On the other hand, in the CA1 region, the number of cells in SDT rats and SDT fatty rats was significantly lower than that in SD rats, and that in SDT fatty rats was significantly lower than that in SDT rats. The GFAP-positive area in SDT fatty rats was significantly reduced compared to that in SD rats only in the DG region. Preliminarily result showed that the expression of S100a9, an inflammation-related gene, was increased in the brains of SDT fatty rats. These results suggest that female SDT fatty rat may exhibit central nervous system diseases due to obesity and DM.

Endurance Exercise Training-Attenuated Diabetic Kidney Disease with Muscle Weakness in Spontaneously Diabetic Torii Fatty Rats

Background: The aim of this study was to evaluate protective effects of endurance exercise training against diabetic kidney disease (DKD) with muscle weakness by using male spontaneously diabetic Torii (SDT) fatty rats as type 2 diabetic animal models with obesity, hypertension, and hyperlipidemia. Methods: Eight-week-old SDT fatty rats (n = 12) and Sprague-Dawley (SD) rats (n = 10) were randomly divided into exercise (Ex; SDT-Ex: n = 6, SD-Ex: n = 5) and sedentary groups (SDT-Cont: n = 6, SD-Cont: n = 5), respectively. Each group underwent regular treadmill exercise 4 times a week from ages 8–16 weeks. Results: The exercise attenuated hypertension and hyperlipidemia and prevented increases in renal parameter levels without affecting blood glucose levels. In the SDT fatty rats, it prevented induction of renal morphological abnormalities in the interstitium of the superficial and intermediate layers of the cortex. Downregulated expression of endothelial nitric oxide synthase in the glomerulus of the SDT fatty rats was significantly upregulated by the exercise. The exercise upregulated the renal expressions of both medium-chain acyl-CoA dehydrogenase and peroxisome proliferator-activated receptor γ coactivator-1α related to fatty acid metabolism. It increased muscle strength and both muscle weight and cross-sectional area of type IIb muscle fibers in the extensor digitorum longus muscle in the SDT fatty rats. Conclusion: Endurance exercise training in type 2 diabetes ameliorates DKD by improving endothelial abnormality and enhancing fatty acid metabolism in addition to attenuated hypertension, hyperlipidemia, and muscle weakness independently of blood glucose levels.

Ocular changes –cataract and retinal lesion- in Spontaneously Diabetic Torii (SDT) fatty rats, an obese type 2 diabetic model

Cataract and retinopathy remain the preventable cause of blindness worldwide, and many pharmacological strategies have been proposed for the treatment of these eye diseases. Animal models play an important role in understanding the pathophysiological features of eye disease and developing for a new therapy. In this study, we investigated the development of cataract and retinal lesion with diabetes using an obese type 2 diabetic models SDT fatty rat. Macroscopic analysis in eyes was performed from 16 to 24 weeks of age and histological analysis was performed at 24 weeks of age. As a result, the lens cloudiness was observed from 19 weeks of age and the degree of the cloudiness was more progressed until 24 weeks of age. Histopathological findings, such as degeneration of lens fiber and shortening and irregular arrangement of cone and rod in retinal tissue, were observed at 24 weeks of age. In conclusion, SDT fatty rats may be useful to understand the pathological features in diabetic cataract and retinopathy develop a new therapy for the disease.

Glomerular hyperfiltration with hyperglycemia in the spontaneously diabetic Torii (SDT) fatty rat, an obese type 2 diabetic model.

Glomerular hyperfiltration is observed in an early stage of kidney diseases including diabetic nephropathy. A better understanding of pathophysiological changes in glomerular hyperfiltration is essential for development of new therapies to prevent kidney disease progression. In this study, we investigated glomerular changes including glomerular filtration rate (GFR) and glomerular size in the Spontaneously Diabetic Torii (SDT) fatty rat, an obese type 2 diabetic model, and we also evaluated pharmacological effects of the sodium glucose cotransporter 2 inhibitor dapagliflozin on the renal lesions. Dapagliflozin was administered to SDT fatty rats from 5 to 17 weeks of age. Blood and urinary biochemical parameters were periodically measured. GFR was determined by transdermal GFR monitor at 16 weeks of age and histopathological analysis was performed at 17 weeks of age. SDT fatty rat developed severe hyperglycemia and exhibited pathophysiological abnormalities in the kidney, such as an increased GFR, glomerular hypertrophy and tissue lesions. Dapagliflozin achieved good glycemic control during the experimental period, inhibited the increase in GFR, and improved histopathological abnormalities in tubules. These results suggest that the SDT fatty rat is a useful model for analyzing the pathogenesis of diabetic nephropathy during its early stage and dapagliflozin improves not only hyperglycemia but also glomerular hyperfiltration and tubule lesions in SDT fatty rat.

Renoprotective effect of GLP-1 receptor agonist, liraglutide, in early-phase diabetic kidney disease in spontaneously diabetic Torii fatty rats.

The aim of this study is to investigate the renoprotective effect of the GLP-1 receptor agonist, liraglutide, in early-phase diabetic kidney disease (DKD) using an animal model of type 2 diabetes with several metabolic disorders. Male 8-week-old spontaneously diabetic Torii (SDT) fatty rats (n = 19) were randomly assigned to three groups. The liraglutide group (n = 6) was injected subcutaneously with liraglutide. Another treatment group (n = 6) received subcutaneous insulin against hyperglycemia and hydralazine against hypertension for matching blood glucose levels and blood pressure with the liraglutide group. The control groups of SDT fatty (n = 7) and non-diabetic Sprague-Dawley rats (n = 7) were injected only with a vehicle. The control group of SDT fatty rats exhibited hyperglycemia, obesity, hypertension, hyperlipidemia, glomerular sclerosis, and tubulointerstitial injury with high urinary albumin and L-FABP levels. Liraglutide treatment reduced body weight, food intake, blood glucose and blood pressure levels, as well as ameliorated renal pathologic findings with lower urinary albumin and L-FABP levels. Liraglutide increased expressions of phosphorylated (p)-eNOS and p-AMPK in glomeruli, downregulated renal expression of p-mTOR, and increased renal expressions of LC3B-II, suggesting activation of autophagy. However, these effects were not caused by the treatments with insulin and hydralazine, despite comparable levels of hyperglycemia and hypertension to those achieved with liraglutide treatment. Liraglutide may exert a renoprotective effect via prevention of glomerular endothelial abnormality and preservation of autophagy in early-phase DKD, independent of blood glucose, and blood pressure levels.

Effects of excessive sodium chloride loading in the spontaneously diabetic torii (SDT) fatty rats, a preclinical model of type 2 diabetes mellitus

Type 2 diabetes mellitus represents an international health concern with its growing number of patients worldwide. At the same time, excessive salt consumption is also seen as a major cause of diseases such as hypertension and may expedite renal complications in diabetic patients. In this study, we investigated the effects of excessive sodium chloride supplementation on the kidney of the Spontaneously Diabetic Torii-Leprfa (SDT fatty) rat, an obese type 2 diabetes model. Male and female SDT fatty rats and normal Sprague-Dawley (SD) rats at 5 weeks of age were loaded with 0.3% sodium chloride (NaCl) in drinking water for 13 weeks. Blood serum and urinary parameters were observed throughout the experiment and kidney samples were examined in histopathological and genetical analyses. Significant changes on the body weight, blood pressure, urine volume, creatinine clearance, blood urea nitrogen (BUN), relative gene expressions of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), monocyte chemotactic protein-1 (MCP-1) and transforming growth factor-β (TGF-β) were observed in the salt-loaded male SDT fatty rats. Urinary L-type fatty acid-binding protein (L-FABP) and albumin levels were higher observed in the salt-loaded male SDT fatty rats throughout the period, but urinary albumin levels in the female SDT fatty rats remain unchanged. In the kidney, slight Armani-Ebstein changes, tubular degeneration, hyaline cast, and inflammatory cell infiltration were observed in female SDT fatty rats while the levels of some changes were higher in the salt-loaded group. The kidney of the salt-loaded male SDT fatty rats demonstrated a higher degree of lesions compared to the female group and the male unloaded group. Histopathological changes in salt-loaded SDT fatty rats show that excessive salt consumption may act as a diabetic pathology exacerbation factor, but the pathology may be influenced by gender difference. Urinary L-FABP levels may act as a useful biomarker to detect slight tubular damages in the kidney. Excessive salt loading was shown to exacerbate the renal injury in SDT fatty rats.

482-P: The GLP-1 Receptor Agonist Liraglutide Improves Glomerular Filtration Rate, Renal Inflammation, and Fibrosis in the Type 2 Diabetic SDT Fatty Rat

The Glucagon-Like Peptide 1 (GLP-1) receptor agonist liraglutide (LIRA) may reduce the rate of development and progression of diabetic kidney disease in type 2 diabetic patients. To evaluate its impact on kidney function, we evaluated the effects of LIRA on glomerular filtration rate (GFR), in both the hyperfiltration and GFR decline phases in the Spontaneously Diabetic Torii (SDT) fatty rat, a preclinical model of type 2 diabetes. SDT fatty male rats were treated subcutaneously, once daily with vehicle or LIRA 0.4mg/kg for 10 weeks. To measure the effects of LIRA on glomerular hyperfiltration, rats were injected with FITC-sinistrin at 4 weeks of treatment to measure GFR. After 5 weeks of treatment, rats underwent unilateral nephrectomy and were put on a 0.3% salt diet to induce a GFR decline for the last weeks of treatment, then GFR was measured at 10 weeks of treatment. Urine biochemistry and kidney histology analysis were also performed. Compared with vehicle, LIRA resulted in significant body weight loss and lower body weight. LIRA also reduced blood glucose levels significantly by up to ∼20%, as expected. During the hyperfiltration phase, LIRA attenuated hyperfiltration, with a 19% lower GFR vs. vehicle (vehicle: 21 ± 1.1 mL/min/kg; LIRA: 17.1 ± 1.0 mL/min/kg, p<0.05 vs. vehicle). In vehicle treated animals, unilateral nephrectomy and 0.3% salt diet induced a major reduction (-56%) in GFR, as expected. After 10 weeks of treatment, LIRA markedly attenuated this GFR decline (vehicle: 9.3 ± 0.5 mL/min/kg; LIRA: 13.3 ± 0.9 mL/min/kg, p<0.001 vs. vehicle). In line with the benefits observed on GFR, LIRA lowered urine albumin to creatinine ratio both in the hyperfiltration and GFR decline phases. Moreover, histology analysis showed that LIRA significantly reduced kidney inflammation and fibrosis scores, as compared with vehicle. In conclusion, LIRA shows significant benefits on GFR, renal inflammation and fibrosis in the SDT fatty rat model. Disclosure F. Briand: Employee; Self; Physiogenex. Stock/Shareholder; Self; Physiogenex. M. Shinohara: None. E. Brousseau: Employee; Self; Physiogenex. Y. Kageyama: None. T. Sulpice: Employee; Self; Physiogenex. Stock/Shareholder; Self; Physiogenex.

2167-PUB: Effect of Low-Available Carbohydrate Diet Containing Okara and Konjac on Blood Glucose Levels in Spontaneous Diabetic Torii Fatty Rats

Background: The ADA and Diabetes UK reported the efficacy of low-carbohydrate diets (LCD) in medical nutrition therapy for blood glucose and lipid management. However, following an LCD may be difficult for many people with diabetes, especially those who consume noodles regularly. To remedy this, we developed a low-available carbohydrate noodle (LACN) using a by-product of Soybean (Glycine max) processing (commonly called “okara”) and Amorphophallus konjac (commonly called Konjac). In this initial study, the effects of the LACN (Figure A) on blood glucose levels (GL) were investigated in Spontaneously Diabetic Torii fatty rats (SDT-fr). Methods: Male, 5-week-old SDT-fr were allocated into two groups based on diet; Group I was fed standard chow (SC) as a control group (n = 6), while Group II was fed SC with 50% LACN (n = 6). The animals were allowed free access to food for 28 days. Results: The plasma GL in the LACN group (Group II) were significantly lower than those in the control group (Figure C), in which body weight (BW) gain was observed (Figure B). Our results, in concurrence with other papers, provide evidence that BW increase in Group II was associated with increase in lean body mass, and that the change in muscle mass of SDT-fr was mainly caused by the LACN intake. Conclusions: LACN might be useful for patients with diabetes or celiac disease who wish to maintain a noodle-based diet. Disclosure K. Suruga: None. T. Tomita: None. M. Kobayashi: None. T. Mitsui: None. K. Kadokura: None.

Relationship between Urinary Liver-Type Fatty Acid-Binding Protein (L-FABP) and Sarcopenia in Spontaneously Diabetic Torii Fatty Rats.

Background Type 2 diabetes (T2D) is a known risk factor for diabetic kidney disease (DKD) and sarcopenia in older patients. Because there may be an interaction between DKD and sarcopenia, the aim of the present study is to investigate the relationship between urinary levels of liver-type fatty acid-binding protein (L-FABP) and sarcopenia using a novel rat model of T2D. Methods Male spontaneously diabetic Torii (SDT) fatty rats (n = 5) at 16 weeks of age were used as an animal model of T2D. Age- and sex-matched Sprague-Dawley (SD) rats (n = 7) were used as controls. Urine samples were obtained from the rats, and muscle strength was evaluated with the use of the forelimb grip test at 16, 20, and 24 weeks of age. Serum, kidney, soleus, and extensor digitorum longus (EDL) muscle samples were collected at 24 weeks of age. Urinary L-FABP levels were measured using dedicated enzyme-linked immunosorbent assays. Results Increased urinary L-FABP levels, focal glomerular sclerosis, moderate interstitial inflammation and fibrosis, and accumulation of renal oxidative proteins were significantly observed in the SDT fatty rats, compared to the SD rats. Muscle weight, muscle strength, cross-sectional areas of both type I and type IIb muscle fibers, and increasing rate of muscle strength were significantly decreased in the SDT fatty rats compared to the SD rats at 24 weeks. Urinary L-FABP levels at 20 and 24 weeks were significantly negatively correlated with muscle strength. Urinary L-FABP levels at 16 weeks were significantly negatively correlated with the increasing rate of muscle strength. Conclusions Urinary L-FABP reflects the degree of muscle strength and weight, as well as cross-sectional areas of muscle fibers. Although further clinical study is needed, urinary L-FABP may be useful to monitor the progression of sarcopenia and DKD in T2D patients.

Pathological Features of Diabetic Retinopathy in Spontaneously Diabetic Torii Fatty Rats.

Objective The Spontaneously Diabetic Torii (SDT) fatty rat, established by introducing the fa allele (obesity gene) of the Zucker fatty rat into the SDT rat genome, is a new model of obese type 2 diabetes. We studied the pathologic features of diabetic retinopathy (DR) in this animal. Methods The eyes of SDT fatty, SDT (controls), and Sprague Dawley (SD) rats (normal controls) were enucleated at 8, 16, 24, 32, and 40 weeks of age (n = 5‐6 for each rat type at each age). The retinal thicknesses, numbers of retinal folds, and choroidal thicknesses were evaluated. Immunostaining for glial fibrillary acidic protein (GFAP) and vascular endothelial growth factor (VEGF) was performed. Quantitative analyses of the immunopositive regions were performed using a cell-counting algorithm. Results The retinas tended to be thicker in the SDT fatty rats and SDT rats than in the SD rats; the choroids tended to be thicker in the SDT fatty rats than in the SD rats. The retinal folds in the SDT fatty rats developed earlier and were more severe than in the SDT rats. Quantitative analyses showed that the GFAP- and VEGF-positive regions in the retinas of the SDT fatty rats were significantly larger than those of the SDT rats. Conclusions SDT fatty rats developed more severe DR earlier than the SDT rats. The SDT fatty rats might be useful as a type 2 diabetes animal model to study DR.

Teriparatide Improves Bone and Lipid Metabolism in a Male Rat Model of Type 2 Diabetes Mellitus.

Osteoporosis is a complication of diabetes mellitus (DM). The pathology of diabetic osteoporosis is distinct from postmenopausal osteoporosis, and there are no specific treatment guidelines for diabetic osteoporosis. In the current study, this issue was addressed by evaluating the effect of osteoporosis medications, such as the anabolic agent PTH [teriparatide (TPTD)] and the antiresorptive agents calcitonin [elcatonin (ECT)] and bisphosphonate [risedronate (RIS)], on bone metabolism as well as on glucose and lipid metabolism in spontaneously diabetic Torii (SDT) fatty rats, which are a model of type 2 DM (T2DM). The medicines were injected subcutaneously into 8-week-old male SDT fatty rats three times weekly for 8 weeks. TPTD treatment in SDT fatty rats increased the osteoblast number and function on trabecular bone in vertebrae, and increased the trabecular bone mass, bone mineral density (BMD), and mechanical strength of vertebrae. Additionally, TPTD improved cortical bone structure and increased BMD. RIS decreased the osteoclast number and function, which led to an increase in vertebral bone mineral content and BMD in the femoral diaphysis, and mechanical strength was increased in the vertebrae. ECT showed no clear effects on bone mass or metabolism. Similar to diabetic lesions, all of the drugs had no effects on hyperglycemia, pancreas morphology, or serum insulin and glucagon levels. However, triglyceride levels and lipid droplets in fatty liver were decreased in the TPTD group. These results suggest that TPTD may be useful for treating fatty liver in addition to osteoporosis in T2DM.