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Research Article

Combination of vildagliptin and ameliorates nonalcoholic fatty liver disease in C57BL/6 mice

Jeyamurugan Mookkan1, Soumita De1,2, Pranesha Shetty1, Nagaraj M. Kulkarni1, Vijayaraj Devisingh1, Mallikarjun S. Jaji1, Vinitha P. Lakshmi1, Shilpee Chaudhary1, Jayanarayan Kulathingal1, Navin B. Rajesh1, Shridhar Narayanan1

ABSTRACT

Objectives: To evaluate the effect of vildagliptin alone and in combination with 1Department of Biology, Drug or rosiglitazone on murine hepatic steatosis in diet-induced nonalcoholic Discovery Research, Orchid fatty liver disease (NAFLD). Chemicals and Pharmaceuticals Materials and Methods: Male C57BL/6 mice were fed with high fat diet (60 Kcal %) Limited, Sozhanganallur, Chennai, and fructose (40%) in drinking water for 60 days to induce NAFLD. After the induction Tamil Nadu, 2Department of period, animals were divided into different groups and treated with vildagliptin (10 Pharmacology, Rolland Institute mg/kg), metformin (350 mg/kg), rosiglitazone (10 mg/kg), vildagliptin (10 mg/kg) + of Pharmaceutical Sciences, metformin (350 mg/kg), or vildagliptin (10 mg/kg) + rosiglitazone (10 mg/kg) orally Berhampur, Orissa, India for 28 days. Following parameters were measured: body weight, food intake, plasma glucose, triglyceride (TG), total cholesterol, liver function tests, and liver TG. Liver Received: 03-01-2013 Revised: 14-06-2013 histopathology was also examined. Accepted: 21-11-2013 Results: Oral administration of vildagliptin and rosiglitazone in combination showed a significant reduction in fasting plasma glucose, hepatic steatosis, and liver TGs. While Correspondence to: other treatments showed less or no improvement in the measured parameters. Dr. Jeyamurugan Mookkan, Conclusions: These preliminary results demonstrate that administration of vildagliptin E-mail: mjeyamurugan@ in combination with rosiglitazone could be a promising therapeutic strategy for the orchidpharma.com treatment of NAFLD.

KEY WORDS: Metformin, NAFLD, non-alcoholic fatty liver disease, rosiglitazone, vildagliptin

Introduction The biological mechanism underlying steatosis occurrence and progression to NAFLD is not yet fully understood. Nonalcoholic fatty liver disease (NAFLD) is the most Association of NAFLD with obesity, , and other common liver disease that occurs in the absence of evident infection or significant consumption of alcohol. NAFLD includes metabolic syndrome suggests hyperglycemia, hyperlipidaemia, different forms of chronic liver damage ranging from a simple and resistance as triggering factors in pathogenesis of [5] fatty infiltration of hepatocytes (steatosis) to steatohepatitis NAFLD. NAFLD can be considered as a hepatic manifestation and fibrosis, and may evolve to cirrhosis and hepatocellular of a metabolic syndrome. NAFLD patients have increase carcinoma.[1] The prevalence of NAFLD is around 15%-40% in subclinical atherosclerosis and it present a higher risk of western and 9%-40% in Asian populations,[2,3] reaching levels mortality from cardiovascular disease compared with those [6] as high as 75%-100% in obese, type-II diabetes, and other without steatosis. These findings have created a surge toward metabolic disease patients.[4] development of strategies to: control obesity, improve glycemic control, enhance insulin sensitivity, and improve β-cell and [7] Access this article online hepatocyte function. Nutritional counseling or diet prescription Quick Response Code: to reduce body weight, coupled with physical exercise remains Website: www.ijp-online.com the first line of treatment. Drug therapy has typically been DOI: 10.4103/0253-7613.125166 focused on the management of associated risk factors such as diabetes, obesity, and hyperlipidemia, being predisposing factors for development of NAFLD.[8] So far, no pharmacological remedy has been approved for treatment of NAFLD. Therefore, for effective treatment of NAFLD, combination of antidiabetic

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Mookkan, et al.: Combination of vildagliptin and rosiglitazone ameliorates NAFLD in mice

agents which are acting through different mechanisms may be (CMC), n = 10) and the animals fed HFD + HFL were further a logical approach. divided homogenously according to body weight (35-37 g), as Vildagliptin is a dipeptidyl peptidase-4 (DPP-4) inhibitor follows, Group II: NAFLD control (0.5% CMC, n = 10), Group III: which increases plasma levels of active glucogon-like vildagliptin (10 mg/kg, n = 7), Group IV: metformin (350 mg/kg,­ peptide-1 (GLP-1), improves glucose-dependent insulin n = 9), Group V: rosiglitazone: (10 mg/kg, n = 7), Group VI: secretion, β-cell function, improves insulin sensitivity, reduces vildagliptin (10 mg/kg) in combination with metformin (350 inappropriate glucagon secretion, and reduces fasting and mg/kg,­ n = 8), Group VII: vildagliptin (10 mg/kg) in combination postprandial glucose.[9] Rosiglitazone is a potent member of with rosiglitazone (10 mg/kg, n = 9). The animals were treated the class and acts as an insulin sensitizer orally once daily for 28 days, during this period food intake and improves glycemic control by increasing peripheral glucose body weight were recorded on a daily basis. disposal and reduces hepatic glucose output through activation Assessment of Biochemical Parameters in Plasma of peroxisome proliferator activator receptor-gamma (PPAR-g). [10] Activation of PPAR-g results in increased free fatty acid Blood was collected from the retroorbital plexus of overnight th uptake by adipocytes, sparing the liver, skeletal muscle, and fasted animals using microcapillary tubes on 29 day and beta cells from the harmful metabolic effects of lipid toxicity.[5] plasma was separated by centrifugation at 3019 G (6000 Metformin is a , suppresses hepatic gluconeogenesis, rpm) for 10 min. The animals were then sacrificed by cervical and enhances insulin-mediated glucose disposal in muscle and dislocation; adipose tissues and liver tissue were excised and fat. Its antilipolytic effect could be beneficial in reducing free weighed. A liver sample from each mouse was kept in 10% fatty acid concentration via restricting efflux from adipose formalin for histopathological examination, while the remaining tissue and improving insulin sensitivity.[11] The present study tissue was frozen (-80°C) for further evaluation. The plasma was designed to assess the effect of vildagliptin alone and glucose, triglyceride (TG), total cholesterol, total bilirubin, in combination with metformin or rosiglitazone on hepatic total protein, alanine aminotransaminase (ALT), aspartate steatosis in diet-induced NAFLD in C57BL/6 mice. aminotransferase (AST), and alkaline phosphatase were measured from plasma by random access clinical chemistry Materials and Methods analyzer Erba XL 300 using a commercially available ERBA Animals diagnostics kit (ERBA diagnostics, Germany). Male C57BL/6 mice aged 4-6 weeks were obtained from Assessment of Liver TGs the animal facility of Orchid Chemicals and Pharmaceutical The liver lipids were extracted using a modified Folch Ltd. (Chennai, India). They were maintained in 12 h light/ extraction protocol.[12] Briefly, approximately 100 mg of liver dark cycle with standard laboratory chow diet and water tissue was homogenized with methanol (1 mL) then centrifuged ad libitum in a controlled environment. All animals were at 1342 G (4000 rpm) for 5 min and the supernatant transferred handled according to the guidelines of experimental animal into a separate tube (15 mL). The pellet was again homogenized care issued by the committee for the purpose of control and with chloroform: methanol (2:1) for 2 min. The homogenate supervision of experiments on animals, Government of India. was then centrifuged and the supernatant separated and mixed The experimental protocol was approved by Institutional Animal with first supernatant. Potassium chloride (0.1 M) was added to Ethics Committee. supernatant and mixed well by vortexing. After centrifugation of Chemical and Reagents the mixture, the bottom phase (organic phase) was transferred Normal chow diet was procured from Nutri Lab® Rodent to a new tube (2 mL). The samples were evaporated in a (Tetragon Chemical Pvt. Ltd., Bangalore, India) and 60 Kcal % Turbovap LV evaporator. Residue was reconstituted in 400 µL high fat diet (HFD) procured from Open Source diets, (New of mixture of N-butyl alcohol: triton X-100: methanol (3:1:1) Brunswik, NJ, USA). Fructose was procured from Sisco Research and mixed properly by vortexing. The samples were used Laboratories (Mumbai, India). Vildagliptin was synthesized for TG estimation using a commercially available kit (ERBA at Orchid Chemicals and Pharmaceuticals Ltd. (Chennai, diagnostics, Germany). India). Metformin and rosiglitazone were received as a gift Assessment of Liver Tissue Histopathology from Sri Sainath chemicals (India) and Dr Reddy’s laboratory (Hyderabad, India). All other chemicals were of reagent grade Liver tissue samples were fixed in 10 % formalin and obtained from standard sources. embedded in paraffin. Sections measuring 5 µm thickness were cut and stained with hematoxylin and eosin (H & E). HFD and High Fructose Liquid Induced NAFLD in Mice Liver histology was examined using the light microscope Male C57BL/6 mice aged 4-6 weeks and body weight ranges (NIKON, ECLIPSE- E200, Japan) and steatosis scoring was 24.29 ± 0.29 g were used for the study. The animals were done according to the NAFLD histological scoring system.[13] divided into two groups, first group (n = 12) fed normal chow diet and the second group (n = 65) fed with 60 Kcal % HFD and Statistical Analysis high fructose liquid 40% (HFL) for 60 days to induce NAFLD. All values are expressed as mean ± standard error mean On 50th day, two animals from normal chow diet and three from and the graphs were generated using Graph-Pad Prism® HFD + HFL were sacrificed to confirm development of NAFLD (Version 4). Statistical analysis was performed by two-way After the induction period, the animals were grouped based analysis of variance (ANOVA), followed by Bonferroni test or on body weight. Animals fed with normal chow diet served as one-way ANOVA followed by Dunnett’s test for all parameters. Group I: Normal control (0.5% sodium carboxymethyl cellulose Results were considered statistically significant at P < 0.05.

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Results were no significant changes observed in other biochemical parameters across the treated groups. Effect of Treatment on Body Weight and Fat Distribution Effect of Different Treatments on Liver Weight The animals fed with HFD + HFL diet for 60 days showed The animals fed with HFD+HFL (Group II) showed an significant increase in body weight compared with chow increase in liver weight compared with Group I animals. The fed animals (P < 0.05). Following 28 days treatment, there Group VII animals treated with vildagliptin in combination was significant reduction (P < 0.01) in body weight gain and with rosiglitazone showed significant reduction in liver weight cumulative feed intake (P < 0.05) in Group VI compared with (P < 0.05) compared with Group II [Table 1]. No significant change Group II and no changes in body weight gain and feed intake in liver weight was observed in the other treatment groups. was observed in other treatment groups [Table 1]. In NAFLD Effect of Treatment on Liver TG Content (Group II) control animals, both epididymal and inguinal fat weight The animals fed with HFD + HFL (Group II) showed more was significantly more (P < 0.01) [Table 1] than normal control TG accumulation as compared with normal chow fed animals animals. None of the treatments had any effect on fat distribution. (Group I). Vildagliptin and rosiglitazone combination treatment Effect of Treatment on Biochemical Parameters (Group VII) reduced TG accumulation as compared with group II The animals fed with HFD + HFL (Group II) developed [P < 0.01, Figure 1]. significant hyperglycemia (P < 0.01) [Table 2] compared with Effect of Treatment on Liver Histopathology chow fed animals (Group I). Rosiglitazone (Group V) treated Development of hepatic steatosis was confirmed by animals did not showed change in AST levels; however, ALT histopathological scoring of H & E-stained liver sections. Liver levels increased which was not significant as compared sections from regular chow fed animals (Group I) had normal with Group II. A significant improvement (P < 0.05) in morphological appearance and scored 0 and HFD + HFL fed plasma glucose level was observed in the group treated animals (Group II) developed moderate to severe macrovesicular with vildagliptin and rosiglitazone combination (Group VII) steatosis and hepatocyte ballooning [Figure 2 b, c] when as compared with Group II. Metformin treatment (Group IV) examined histopathologically and had an average score (P < significantly reduced AST level (P < 0.05) [Table 2]. There 0.01) compared with Group I [Figure 3]. The animals treated

Table 1:

Effect of vildagliptin, metformin, and rosiglitazone (alone and in combination) on body weight, fat distribution, and liver weight in high fat diet-induced nonalcoholic fatty liver disease in mice

Group Initial body Final body Cumulative feed Liver weight (g) Epididymal fat (g) Inguinal fat (g) weight (g) weight (g) intake (g) Group I 30.09±3.04 31.28±1.21 84.91±4.68 1.36±0.06 0.61±0.10 0.32±0.05 Group II 36.51±2.65$ 39.77±3.16$$ 43.18±2.40 1.82±0.15 1.47±0.19$$ 1.40 ±0.35$$ Group III 37.43±1.73 39.92±3.21 45.75±2.68 1.62±0.13 1.31±0.34 1.08±0.41 Group IV 36.04±1.61 36.92±1.48 42.27±2.48 1.59±0.08 1.25±0.19 0.85±0.13 Group V 36.02±1.74 37.80±1.61 37.33±2.05 1.89±0.31 1.46±0.17 1.16±0.14 Group VI 36.28±1.63 34.60±1.34* 23.18±1.32* 1.48±0.09 1.24±0.09 0.90±0.14 Group VII 35.57±1.33 36.96±1.04 24.99±1.33 1.22±0.11* 1.27±0.14 0.87±0.17 Group I = Normal control, Group II = Nonalcoholic fatty liver disease control, Group III = Vildagliptin (10 mg/kg), Group IV = Metformin (350 mg/kg), Group V = Rosiglitazone (10 mg/kg), Group VI = Vildagliptin (10 mg/kg) + metformin (350 mg/kg), Group VII = Vildagliptin (10 mg/kg) + rosiglitazone (10 mg/kg), Values are expressed as (mean ± standard error of the mean, n = 7−10), $P < 0.05, $$P < 0.01 as compared with Group I, *P < 0.05 as compared with Group II

Table 2:

Effect of vildagliptin, metformin, and rosiglitazone (alone and in combination) on plasma biochemical parameters in high fat diet-induced nonalcoholic fatty liver disease in mice

Group Glucose(mg/dL) Total Cholesterol Triglyceride Total bilirubin AST (IU/L) ALT (IU/L) ALP (IU/L) Protein(g/dL) (mg/dL) (mg/dL) (mg/dL) Group I 137.4±12.29 6.04±0.08 119.70±7.66 145.00±9.35 4.24±0.18 128.44±20.5 41.58±6.39 90.30±16.56 Group II 315.13±19.29 $$ 5.97±0.11 128.50±13.36 106.90±6.73 $$ 3.55±0.32 119.50±13.74 58.67±7.04 59.40±15.75 Group III 269.31±43.45 5.86±0.15 99.57±18.53 93.00±13.45 3.22±0.51 92.72±8.96 47.33±8.70 26.86±3.67 Group IV 258.44±21.59 6.00±0.11 119.44±12.27 92.89±7.05 3.66±0.17 71.81±3.66* 32.21±4.20 55.78±12.37 Group V 237.8±17.57 5.84±0.14 129.00±13.96 95.00±5.41 3.35±0.17 118.86±13.18 80.96±22.18 48.25±12.68 Group VI 249.56±21.99 6.08±0.18 111.25±14.44 90.25±7.71 3.47±0.32 71.51±3.49 28.09±4.05 35.57±5.42 Group VII 225.72±18.61* 5.79±0.19 98.00±8.77 82.11±6.20 2.74±0.20 78.71±7.61 27.72±4.16 34.00±5.96 Group I = Normal control, Group II = Nonalcoholic fatty liver disease control, Group III = Vildagliptin (10 mg/kg), Group IV = Metformin (350 mg/kg), Group V = Rosiglitazone (10 mg/kg), Group VI = Vildagliptin (10 mg/kg) + metformin (350 mg/kg), Group VII = Vildagliptin (10 mg/kg) + rosiglitazone (10 mg/kg), AST = Aspartate aminotransferase, ALT = Alanine transaminase, ALP = Alkaline phosphatase, Values are expressed as (mean ± standard error of the mean, n = 7−10), $P < 0.05, $$P < 0.01 as compared with Group I, *P < 0.05 as compared with Group II

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with vildagliptin and rosiglitazone combination (Group VII) liver enzyme levels do not readily correlate with severity of showed prominent improvement in steatosis [Figure 2h] and hepatic steatosis.[14] These observed features are similar to the significant reduction in steatosis score (P < 0.01) [Figure 3], pathological features of human NAFLD. In the NAFLD control as compared with Group II. No significant change in hepatic group, the animals showed significant reduction in plasma TG steatosis score was observed in other treatment groups. with corresponding increase in liver TG levels as compared with normal controls. Though such a reduction seems contrary Discussion with human metabolic syndrome condition, it has already The study focused on the effect of vildagliptin alone and been reported by other researchers.[15] In response to sudden in combination with metformin and rosiglitazone in high fat excessive fat ingestion when the plasma lipid level exceeds and fructose liquid diet-induced NAFLD in C57BL/6 mice. The oxidative capacity of energy requiring tissues like skeletal NAFLD animals developed marked obesity, hyperglycemia, and muscle, the liver acts as an effective buffer organ to avoid fatty liver. Histopathological examination of the livers of NAFLD accumulation of circulating lipid and starts taking up lipid from control mice revealed severe hepatic fat accumulation along plasma to store as TG.[14] Excessive stored TG in hepatocytes with increased liver weight; however, this was accompanied is the hallmark of NAFLD which is strongly associated with with only mild elevation of liver specific enzymes. A lack of hyperinsulinemia and hyperglycemia.[16] correlation between the degree of NAFLD and levels of liver In the present study, the doses administered to the enzymes is not surprising, since in a clinical situation the treatment groups were based on previous studies in rodents.[17-19] Previous reports revealed metformin improved Figure 1: Effect of vildagliptin, metformin, and rosiglitazone (alone fatty liver disease, reversing hepatomegaly, steatosis, and and in combination) on liver triglyceride in high fat diet-induced aminotransferase abnormalities in ob/ob mice with fatty liver.[17] nonalcoholic fatty liver disease in mice. Group I: Normal control; In this study, treatment with metformin showed significant Group II: Nonalcoholic fatty liver disease control; Group III: vildagliptin reduction in body weight gain without much change in food (10 mg/kg); Group IV: metformin (350 mg/kg); Group V: rosiglitazone (10 mg/kg); Group VI: vildagliptin (10 mg/kg) + metformin (350 mg/kg); intake and showed significant reduction in AST levels, but Group VII: vildagliptin (10 mg/kg) + rosiglitazone (10 mg/kg). Values are there was no improvement in other biochemical parameters expressed as mean ± standard error of the mean, n = 7−10. ** P < 0.01 tested, consistent with previous report,[20] and metformin in as compared with Group II combination with vildagliptin also showed significant reduction in gain in body weight and food intake and only slight reduction in other biochemical parameters. The reduction in body weight and food intake may be because of the combined effect of metformin and vildagliptin on incretin hormone glucagon like peptide-1 (GLP-1).[21] Histopathological examination of liver sections revealed only mild improvement in hepatic vacuolation (steatosis) in metformin-treated animals and also in vildagliptin and metformin combination-treated animals. Rosiglitazone has been reported to reverse hepatic steatosis and lower intramyocellular lipids in Zucker fatty rat,[22] attenuate liver inflammation and insulin resistance in methionine and choline-deficient diet induced steatosis in Wistar rats.[23]

Figure 2: Effect of vildagliptin, metformin, and rosiglitazone (alone and in combination) on liver histology in high fat diet-induced nonalcoholic fatty liver disease in mice (a) Normal control, (b and c) Nonalcoholic fatty liver disease control: profound marked hepatic steatosis and ballooning, (d) vildagliptin (10 mg/kg), (e) metformin (350 mg/kg), (f) rosiglitazone (10 mg/kg), (g) vildagliptin (10 mg/kg) + metformin (350 mg/kg), (h) vildagliptin (10 mg/kg) + rosiglitazone (10 mg/kg): reduced hepatic steatosis and ballooning. H & E staining of liver tissue (×10, 50 µm)

a b c d

e f g h

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Figure 3: Effect of vildagliptin, metformin, and rosiglitazone (alone and fatty liver disease. World J Hepatol 2010;2:139-42. in combination) on liver histopathological score in high fat diet-induced 7. Duvnjak M, Lerotic I, Barsic N, Tomasic V, Virovic Jukic L, Velagic V. Pathogenesis nonalcoholic fatty liver disease in mice and management issues for non-alcoholic fatty liver disease. World J Gastroenterol 2007;13:4539-50. 8. van der Poorten D, George J. Current and novel therapies for the treatment of nonalcoholic steatohepatitis. Hepatol Int 2007;1:343-54. 9. Michael H, Martin F, Standl E. Vildagliptin-An oral dipeptidyl peptidase-4 inhibitor for type 2 diabetes. US Endocrine Dis 2006;2:75-81. 10. Kim HJ, Kim SK, Shim WS, Lee JH, Hur KY, Kang ES, et al. Rosiglitazone improves insulin sensitivity with increased serum leptin levels in patients with type 2 diabetes mellitus. Diabetes Res Clin Pract 2008;81:42-9. 11. Ren T, He J, Jiang H, Zu L, Pu S, Guo X, et al. Metformin reduces lipolysis in primary rat adipocytes stimulated by tumor necrosis factor-alpha or isoproterenol. J Mol Endocrinol 2006;37:175-83. 12. Folch J, Lees M, Sloane Stanley GH. A simple method for the isolation and purification of total lipids from animal tissue. J Biol Chem 1957;226:497-509. 13. Kleiner DE, Brunt EM, Van Natta M, Behling C, Contos MJ, Cummings OW, et al, Ironically, it causes an increase in microvesicular steatosis and Nonalcoholic Steatohepatitis Clinical Research Network. Design and validation of a histological scoring system for nonalcoholic fatty liver disease. Hepatology liver enzymes in ob/ob mice.[22] Perhaps in db/db mice treated 2005;41:1313-21. with rosiglitazone in combination with vildagliptin showed 14. Spruss A, Bergheim I. Dietary fructose and intestinal barrier: Potential risk improvement in plasma TG and glucose. In this study, treatment factor in the pathogenesis of nonalcoholic fatty liver disease. J Nutr Biochem with rosiglitazone failed to show improvement in liver weight 2009;20:657-62. and histopathology or any other parameter measured. The mild 15. Gauthier MS, Favier R, Lavoie JM. Time course of the development of non- elevation in ALT level observed may be because of the adverse alcoholic hepatic steatosis in response to high-fat diet induced obesity in rats. [24] Br J Nutr 2006;95:273-81. effect of the rosiglitazone. Interestingly, the animals treated 16. Musso G, Gambino R, Cassader M. Recent insights into hepatic lipid with combination of vildagliptin and rosiglitazone showed metabolism in non-alcoholic fatty liver disease (NAFLD). Prog Lipid Res significant reduction in fasting plasma glucose, liver weight, 2009;48:1-26. and hepatic TG levels. Also, the histological examination of liver 17. Liu LF, Purushotham A, Wendel AA, Belury MA. Combined effects of sections showed significant improvement in hepatic steatosis. rosiglitazone and conjugated linoleic acid on adiposity, insulin sensitivity, and hepatic steatosis in high-fat-fed mice. Am J Physiol Gastrointest Liver Physiol This improvement in histopathology may be attributed to 2007;292:G1671-82. decreased liver TG eventually leading to reduction in fasting 18. Lin HZ, Yang SQ, Chuckaree C, Kuhajda F, Ronnet G, Diehl AM. Metformin glucose level.[7] Clinically, the combination of PPAR-γ agonist reverses fatty liver disease in obese, leptin-deficient mice. Nat Med and DPP-4 inhibitor showed good efficacy in terms of controlling 2000;6:998-1003. fasting glucose compared with monotherapy in diabetic 19. Davis JA, Singh S, Sethi S, Roy S, Mittra S, Rayasam G, et al. Nature of action of , the dipeptidyl peptidase-IV inhibitor in diabetic animals. Indian J patients.[25] Consistence with these results, vildagliptin and Pharmacol 2010;42:229-33. rosiglitazone combination showed improvement in the fatty 20. Yasuda N, Inoue T, Nagakura T, Yamazaki K, Kira K, Saeki T, et al. Metformin liver disease as compared with monotherapy. causes reduction of food intake and body weight gain and improvement of glucose In conclusion, our study indicates that the animals tolerance in combination with dipeptidyl peptidase IV inhibitor in Zucker fa/fa rats. treated with vildagliptin and rosiglitazone combination J Pharmacol Exp Ther 2004;310:614-9. showed significant reduction in hepatic steatosis and TG s. 21. Maida A, Lamont BJ, Cao X, Drucker DJ. Metformin regulates the incretin receptor axis via a pathway dependent on peroxisome proliferator-activated receptor-α in However, further studies are needed to be done to evaluate mice. Diabetologia 2011;54:339-49. the mechanism involved in reversal of hepatic steatosis. In 22. Hockings PD, Changani KK, Saeed N, Reid DG, Birmingham J, O’Brien P, this preliminary study, the results suggest that combination et al. Rapid reversal of hepatic steatosis, and reduction of muscle triglyceride, therapy of a DPP-4 inhibitor with a PPAR-g agonist may be a by rosiglitazone: MRI/S studies in Zucker fatty rats. Diabetes Obes Metab new therapeutic strategy for the treatment of NAFLD. 2003;5:234-43. 23. Tahan V, Eren F, Avsar E, Yavuz D, Yuksel M, Emekli E, et al. Rosiglitazone References attenuates liver inflammation in a rat model of nonalcoholic steatohepatitis. Dig Dis Sci 2007;52:3465-72. 1. Federico A, Niosi M, Blanco CD, Loguercio C. Emerging drugs for Non-alcoholic 24. García-Ruiz I, Rodríguez-Juan C, Díaz-Sanjuán T, Martínez MA, Muñoz-Yagüe T, fatty liver disease. Expert Opin Emerg Drugs 2008;13:145-58. Solís-Herruzo JA. Effects of rosiglitazone on the liver histology and mitochondrial 2. Ahamed HA, Abu EO, Byrne CD. Non-Alcoholic Fatty Liver Disease (NAFLD): New function in ob/ob mice. Hepatology 2007;46:414-23. challenge for general practitioners and important burden for health authorities? 25. Garber AJ, Schweizer A, Baron MA, Rochotte E, Dejager S. Vildagliptin in Prim Care Diabetes 2010;4:129-37. combination with improves glycaemic control in patients with type 2 3. Varela-Rey M, Embade N, Ariz U, Lu SC, Mato JM, Martinez-Chantar ML. diabetes failing thiazolidinedione monotherapy: A randomized, placebo-controlled Non-alcoholic steatohepatitis and animal models: Understanding the human study. Diabetes Obes Metab 2007;9:166-74. disease. Int J Biochem Cell Biol 2009;41:969-76. 4. Tessari P, Coracina A, Cosma A, Tiengo A. Hepatic lipid metabolism and Cite this article as: Mookkan J, De S, Shetty P, Kulkarni NM, Devisingh V, non-alcoholic fatty liver disease. Nutr Metab Cardiovasc Dis 2009;19:291-302. Jaji MS, et al. Combination of vildagliptin and rosiglitazone ameliorates 5. Vanni E, Bugianesi E, Kotronen A, De Minicis S, Yki-Järvinen H, Svegliati- nonalcoholic fatty liver disease in C57BL/6 mice. Indian J Pharmacol Baroni G. From the metabolic syndrome to NAFLD or vice versa? Dig Liver Dis 2014;46:46-50. 2010;42:320-30. 6. Filippatos TD, Elisaf MS. Combination drug treatment in patients with non-alcoholic Source of Support: Nil, Conflict of Interest: No.

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