ABSTRACT
Title
Comparative therapeutic effects of sodium butyrate and BuToRo® in a model of nonalcoholic steatohepatitis in the young rat.
Authors
G. Mattace Raso1, R. Simboli1, A. Iacono1, G. D’Agostino1, A. Santoro1, P. Amero1, G. La Rana1, R. Russo1, O. Paciello2, R. Berni Canani3,4, A. Calignano1, R. Meli1
1Dipartimento di Farmacologia Sperimentale,2Department of Pathology and Animal Health, 3Dipartimento di Pediatria, 4ELFID Università degli Studi di Napoli “Federico II”;Napoli.
1Dipartimento di Farmacologia Sperimentale,2Department of Pathology and Animal Health, 3Dipartimento di Pediatria, 4ELFID Università degli Studi di Napoli “Federico II”;Napoli.
Abstract
Nonalcoholic fatty liver disease (NAFLD) is the most common form of chronic liver disease in the pediatric population. Insulin resistance (IR) appears to be critical in its pathogenesis and also present in lean non-diabetic patients. Experimental studies support the pathogenic role of an altered intestinal permeability and/or an alteration of resident microbiota for fatty liver and IR development. Thus, we evaluated the potential utility of sodium butyrate (BuNa) or its synthetic derivative N-(1-carbamoyl-2-phenyl-ethyl)butyramide (BuToRo®) able to release butyrate at intestinal level, in the prevention of steatosis.
To this purpose, we used an experimental model of steatosis feeding young rats with a high fat diet (HFD) rich in usaturated and saturated fats.
Just after weaning, male Sprague-Dawley rats were divided into three groups as following: 1) a control group receiving the standard diet (STD; 10.5% fat, 16.4% proteins, and 73.1% carbohydrates; 4.06Kcal/g); 2) a HFD fed group (HFD; 58.0% fat, 16.4% protein, and 25.5 carbohydrates; 5.6kcal/g); 3) HFD fed animals treated by gavage with sodiumbutyrate (HFD+BuNa, 20 mg/Kg/die) or 4) with BuToRo® (HFD+BuToRo® 42.5 mg/Kg/die, the equimolecular dose of BuNa) for 5 weeks.
In the early state of pathology, body weight gain, caloric intake, fat mass, triglycerides and liver weight did not vary among groups. Interestingly, liver from HDF rats showed a histological pattern characterized by microvesicular steatosis with the hepatocytes showing the cytoplasm filled with small vacuoles uniform in size and smaller than the centrally located nucleous. Furthermore, foci of mixed inflammatory cell infiltration and hepatocyte necrosis or apoptosis appeared throughout the lobule. Moreover, HFD showed a marked increase in serum aminotransferases and in fasting glucose level associated to an impairment of glucose tolerance impairment. IR (evaluated as HOMA index) occurred in HFD was associated to a reduction in GLUT4 expression in adipose tissue. HFD induced a strong increase in TNF-a, inflammatory enzymes, such as COX-2 and iNOS, and in MCP-1 in liver tissue. Furthermore, in HFD animals PPAR-αe PPAR-γexpression were reduced in liver and adipose tissue, respectively.
Comparative evaluation of these two preparations of butyrate showed a similar histological pattern characterized by low grade of steatosis with microvescicular findings, scattered foci of inflammatory cells and few apoptotic nuclei. Moreover both drugs showed a similar potency in the normalisation of several variables, such as AST, ALT and HOMA index, even if BuToRo® showed a stronger effect on reducing fasting glucose and reconstituting glucose tolerance. Both treatment significantly reduced TNF-aexpression and restored GLUT-4 and PPARs. Finally a higher potency of BuToRo® was showed in reducing pro-inflammatory enzymes in the liver.
Our results demonstrated a protective effect of butyrate in limiting molecular events underlying the onset of insulin resistance and NAFLD, suggesting a potential clinical relevance. In particular, BuToRo® could represent an alternative therapeutic tool to BuNa, sharing a comparable efficacy, but a higher compliace.
To this purpose, we used an experimental model of steatosis feeding young rats with a high fat diet (HFD) rich in usaturated and saturated fats.
Just after weaning, male Sprague-Dawley rats were divided into three groups as following: 1) a control group receiving the standard diet (STD; 10.5% fat, 16.4% proteins, and 73.1% carbohydrates; 4.06Kcal/g); 2) a HFD fed group (HFD; 58.0% fat, 16.4% protein, and 25.5 carbohydrates; 5.6kcal/g); 3) HFD fed animals treated by gavage with sodiumbutyrate (HFD+BuNa, 20 mg/Kg/die) or 4) with BuToRo® (HFD+BuToRo® 42.5 mg/Kg/die, the equimolecular dose of BuNa) for 5 weeks.
In the early state of pathology, body weight gain, caloric intake, fat mass, triglycerides and liver weight did not vary among groups. Interestingly, liver from HDF rats showed a histological pattern characterized by microvesicular steatosis with the hepatocytes showing the cytoplasm filled with small vacuoles uniform in size and smaller than the centrally located nucleous. Furthermore, foci of mixed inflammatory cell infiltration and hepatocyte necrosis or apoptosis appeared throughout the lobule. Moreover, HFD showed a marked increase in serum aminotransferases and in fasting glucose level associated to an impairment of glucose tolerance impairment. IR (evaluated as HOMA index) occurred in HFD was associated to a reduction in GLUT4 expression in adipose tissue. HFD induced a strong increase in TNF-a, inflammatory enzymes, such as COX-2 and iNOS, and in MCP-1 in liver tissue. Furthermore, in HFD animals PPAR-αe PPAR-γexpression were reduced in liver and adipose tissue, respectively.
Comparative evaluation of these two preparations of butyrate showed a similar histological pattern characterized by low grade of steatosis with microvescicular findings, scattered foci of inflammatory cells and few apoptotic nuclei. Moreover both drugs showed a similar potency in the normalisation of several variables, such as AST, ALT and HOMA index, even if BuToRo® showed a stronger effect on reducing fasting glucose and reconstituting glucose tolerance. Both treatment significantly reduced TNF-aexpression and restored GLUT-4 and PPARs. Finally a higher potency of BuToRo® was showed in reducing pro-inflammatory enzymes in the liver.
Our results demonstrated a protective effect of butyrate in limiting molecular events underlying the onset of insulin resistance and NAFLD, suggesting a potential clinical relevance. In particular, BuToRo® could represent an alternative therapeutic tool to BuNa, sharing a comparable efficacy, but a higher compliace.