Effects of the Soluble Fiber Complex PolyGlycopleX on Glucose Homeostasis and Body Weight in Young Zucker Diabetic Rats.

Gary James Grover,Joan Wicks,Lee Koetzner,Michael R Lyon,Raylene A Reimer,Roland J Gahler,Simon Wood

doi:10.3389/fphar.2011.00047

Abstract

Dietary fiber can reduce insulin resistance, body weight, and hyperlipidemia depending on fiber type, water solubility, and viscosity. PolyGlycopleX® (PGX®) is a natural, novel water soluble, non-starch polysaccharide complex that with water forms a highly viscous gel compared to other naturally occurring dietary fiber. We determined the effect of dietary PGX® vs. cellulose and inulin on the early development of insulin resistance, body weight, hyperlipidemia, and glycemia-induced tissue damage in young Zucker diabetic rats (ZDFs) in fasted and non-fasted states. ZDFs (5 weeks old) were fed a diet containing 5% (wgt/wgt) cellulose, inulin, or PGX® for 8 weeks. Body weight, lipids, insulin, and glucose levels were determined throughout the study and homeostasis model assessment (HOMA) was used to measure insulin sensitivity throughout the study in fasted animals. At study termination, insulin sensitivity (oral glucose tolerance test, OGTT) and kidney, liver, and pancreatic histopathology were determined. Body weight and food intake were significantly reduced by PGX® vs. inulin and cellulose. Serum insulin in fasted and non-fasted states was significantly reduced by PGX® as was non-fasted blood glucose. Insulin resistance, measured as a HOMA score, was significantly reduced by PGX® in weeks 5 through 8 as well as terminal OGTT scores in fed and fasted states. Serum total cholesterol was also significantly reduced by PGX®. PGX® significantly reduced histological kidney and hepatic damage in addition to reduced hepatic steatosis and cholestasis. A greater mass of pancreatic β-cells was found in the PGX® group. PGX® therefore may be a useful dietary additive in the control of the development of the early development of the metabolic syndrome.

Highlights

Dietary fiber is generally accepted as having efficacy in disease states including colorectal cancer, obesity, cardiovascular disease, insulin resistance, and diabetes (Wilson and Wilson, 1984; Hill, 1997; Howarth et al, 2001; Grunberger et al, 2006; Panahi et al, 2007)
The effects of non-digestible dietary fiber are variable depending on their physicochemical properties with viscous, water soluble fibers being more efficacious for lipid reduction, weight reduction, and improved glycemic control compared to insoluble, low viscosity fibers (Blackwood et al, 2000; Jenkins et al, 2000; Panahi et al, 2007)
Our goal was to determine the effects of PGX® on food intake, body weight, glycemic control, and lipids profile in ZDFs as well as histomorphometric assessment of liver, pancreas, and kidney damage seen in developing diabetes

Summary

Introduction

Dietary fiber is generally accepted as having efficacy in disease states including colorectal cancer, obesity, cardiovascular disease, insulin resistance, and diabetes (Wilson and Wilson, 1984; Hill, 1997; Howarth et al, 2001; Grunberger et al, 2006; Panahi et al, 2007). High viscosity fibers interfere with ileal bile acid absorption thereby reducing cholesterol re-absorption as well as increasing hepatic cholesterol metabolism and breakdown (Judd and Truswell, 1982; Ganji and Kies, 1994). Fibers such as pectin lower hepatic lipid and triglyceride levels, these effects are variable, depending on the model and specific fiber involved (Wilson and Wilson, 1984; Williams, 1991; Anderson et al, 1994)

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