Differential blood lipid-lowering effects of alkylsulfonated chitosan of different molecular weights in Syrian hamsters in vivo

Abstract

Abstract. This study investigated the effects of alkylsulfonated chitosan of different molecular weights on intestinal lipid absorption, blood lipid profiles and circulating adhesion molecules. Syrian hamsters were fed an AIN-93G-based high-fat diet (HFD) and were orally administered 5 or 10 mg/kg BW of oligomer (6 kDa) chitosan (OC), low-molecular-weight (70 kDa) chitosan (LMC) or high-molecular-weight (200 kDa) chitosan (HMC) four times per week for 12 weeks. Animals receiving 2.5 mg/kg BW lovastatin (LOVA) served as a positive control. The blood lipid profiles of these control animals revealed that all chitosans and LOVA significantly decreased total triglyceride, total cholesterol, low-density lipoprotein (LDL)-cholesterol and very-low-density lipoprotein (VLDL)-cholesterol levels in a dose-dependent manner compared to the HFD-fed controls (P<0.05). The blood lipid lowering effectiveness of the three chitosans followed the order of LMC>OC>HMC. Hamsters receiving 5 and 10 mg/kg LMC (P<0.05) exhibited an increase in fecal fat content. Immunoblot assay revealed that acyl-coenzyme A:cholesterol acyltransferase-2 (ACAT-2) expression was suppressed in all chitosan-fed animals compared to the HFD-fed controls (P<0.05). These results suggest that chitosan effectively decreases blood lipid content, and its effectiveness depends on the molecular size of chitosan. The hypolipidemic effect of chitosan is partly attributed to its suppression of intestinal lipid absorption and hepatic ACAT-2 expression.

Chitosan promotes immune responses, ameliorating total mature white blood cell numbers, but increases glutamic oxaloacetic transaminase and glutamic pyruvic transaminase, and ameliorates lactate dehydrogenase levels in leukemia mice in vivo

“…Previous studies have demonstrated that the hydrolyzed products of chitosan (chitosan oligosaccharide) have biological activities, but the majority of these studies are in vitro or treated in animals via intravenous or intraperitoneal administration ( 26 – 28 ). In our primary studies, chitosan was demonstrated to have hypolipidemic effects which partly involved the suppression of intestinal lipid absorption and hepatic acyl coenzyme A:cholesterol acyltransferase-2 expression ( 29 ), and chitosan slowed down the rate of tumor growth; however, it did not inhibit tumor formation ( 29 ). So far, there is no available information on if chitosan affects immune responses in leukemia mice.…”

Chitosan promotes immune responses, ameliorates glutamic oxaloacetic transaminase and glutamic pyruvic transaminase, but enhances lactate dehydrogenase levels in normal mice in vivo

“…Although numerous studies have shown that chitosan is able to inhibit the growth of microbial organisms ( 7 – 11 ), it has also been shown to cause significant downregulation of the expression of pro-inflammatory markers CD86 and MHCII on macrophages, decrease the expression of the pro-inflammatory cytokine TNF-α and increase that of the anti-inflammatory cytokines IL-10 and TGF-β1 ( 12 , 13 ). In addition, our earlier study has shown that the hypolipidemic effect of chitosan is partly attributed to its suppression of intestinal lipid absorption and hepatic acyl-coenzyme A: cholesterol acyltransferase-2 expression ( 18 ). Furthermore, chitosan has also been found to slow down the rate of tumor growth without inhibiting tumor formation ( 14 ); however, no detailed analysis of the immune responses in chitosan-treated animals, including mice, has been reported.…”