Dehulled Adlay (Coix lachryma-jobi L.) ameliorates hepatic gluconeogenesis and steatosis in streptozotocin/high-fat diet-induced diabetic rats

Adlay (Coix lachryma-jobi L.) is a traditional Chinese herbal medicine with various biological activities. We investigated the anti-diabetic effects of different parts of adlay seeds, including polished adlay (PA), adlay bran (AB) and dehulled adlay (DA) in a streptozotocin (STZ)/high fat diet (HFD) diabetic rat model (DM). DM rats supplemented with or without PA (43%), AB (3%), or DA (46%) diet for 8 weeks. The plasma glucose and insulin levels and the insulin resistance index (HOMA-IR) were increased in DM group; among the three adlay diets, DA has the best effects attenuating all of these alterations in DM rats. Both AB and DA alleviated diabetes-impaired glucose tolerance. The increased hepatic phosphoenolpyruvate carboxykinase protein expression in DM group was improved by all of the three adlay diets. The increased ratio of glucose-6-phosphatase to glucokinase in DM group was suppressed by DA supplementation, further suggesting DA diet is most effective among the three diets. Both AB and DA diets had beneficial effects against hepatic steatosis, with better effects observed in DA group. These results suggest that the DA diet, composed of both polished adlay and adlay bran, possesses the best potential to improve glucose homeostasis, at least in part, by alleviating hepatic glucose metabolism and steatosis.

Correction: Green sweet potato leaves increase Nrf2-mediated antioxidant activity and facilitate benzo[a]pyrene metabolism in the liver by increasing phase II detoxifying enzyme activities in rats

Correction for 'Green sweet potato leaves increase Nrf2-mediated antioxidant activity and facilitate benzo[a]pyrene metabolism in the liver by increasing phase II detoxifying enzyme activities in rats' by Ray-Yu Yang et al., Food Funct., 2022, https://doi.org/10.1039/d2fo01049f.

Green sweet potato leaves increase Nrf2-mediated antioxidant activity and facilitate benzo[a]pyrene metabolism in the liver by increasing phase II detoxifying enzyme activities in rats

Green and purple SPL consumption may enhance the Nrf2-mediated hepatic antioxidant activity and modulate xenobiotic-metabolizing enzymes and transporters via different mechanisms.

Influence of Dietary Chitosan Feeding Duration on Glucose and Lipid Metabolism in a Diabetic Rat Model

This study was designed to investigate the influence of dietary chitosan feeding-duration on glucose and lipid metabolism in diabetic rats induced by streptozotocin and nicotinamide [a non-insulin-dependent diabetes mellitus (NIDDM) model]. Male Sprague-Dawley rats were used as experimental animals and divided into short-term (6 weeks) and long-term (11 weeks) feeding durations, and each duration contained five groups: (1) control, (2) control + 5% chitosan, (3) diabetes, (4) diabetes + 0.8 mg/kg rosiglitazone (a positive control), and (5) diabetes + 5% chitosan. Whether the chitosan feeding was for 6 or 11 weeks, the chitosan supplementation decreased blood glucose and lipids levels and liver lipid accumulation. However, chitosan supplementation decreased plasma tumor necrosis factor (TNF)-α, insulin levels, alanine aminotransferase (ALT) activity, insulin resistance (HOMA-IR), and adipose tissue lipoprotein lipase activity. Meanwhile, it increased plasma high-density lipoproteins (HDL)-cholesterol level, plasma angiopoietin-like-4 protein expression, and plasma triglyceride levels (at 11-week feeding duration only). Taken together, 11-week (long-term) chitosan feeding may help to ameliorate the glucose and lipid metabolism in a NIDDM diabetic rat model.

Chitosan Oligosaccharide Alleviates Abnormal Glucose Metabolism without Inhibition of Hepatic Lipid Accumulation in a High-Fat Diet/Streptozotocin-Induced Diabetic Rat Model

This study investigated the effects of chitosan oligosaccharide (COS) on glucose metabolism and hepatic steatosis in a high-fat (HF) diet/streptozotocin-induced diabetic rat model. Male Wistar rats were divided into: (1) normal control (NC group), (2) HF diet (HF group), (3) streptozotocin (STZ)-induced diabetes with HF diet (DF group), and DF group supplemented with (4) 0.5% COS (D0.5F group), (5) 1% COS (D1F group), and (6) 5% COS (D5F group) for 4 weeks. COS supplementation significantly decreased the plasma glucose, BUN, creatinine, uric acid, triglyceride (TG), and total cholesterol (TC) levels, and hepatic glucose-6-phosphatase activity, and significantly increased hepatic hexokinase activity and glycogen content in diabetic rats; but the increased hepatic TG and TC levels could not be significantly decreased by COS supplementation. Supplementation of COS increased superoxide dismutase activity and decreased lipid peroxidation products in the diabetic rat livers. COS supplementation significantly increased phosphorylated AMP-activated protein kinase (AMPK) protein expression, and attenuated protein expression of hepatic phosphoenolpyruvate carboxykinase (PEPCK) and phosphorylated p38 and renal sodium-glucose cotransporter-2 (SGLT2) in diabetic rats. These results suggest that COS may possess a potential for alleviating abnormal glucose metabolism in diabetic rats through the inhibition of hepatic gluconeogenesis and lipid peroxidation and renal SGLT2 expression.

Effects of Chitosan Oligosaccharide on Plasma and Hepatic Lipid Metabolism and Liver Histomorphology in Normal Sprague-Dawley Rats

Chitosan oligosaccharide is known to ameliorate hypercholesterolemia and diabetes. However, some studies found that chitosan oligosaccharide might induce mild to moderate hepatic damage in high-fat (HF) diet-induced obese rats or diabetic rats. Chitosan oligosaccharide can be as a dietary supplement, functional food, or drug. Its possible toxic effects to normal subjects need to be clarified. This study is designed to investigate the effects of chitosan oligosaccharide on plasma and hepatic lipid metabolism and liver histomorphology in normal Sprague-Dawley rats. Diets supplemented with 5% chitosan oligosaccharide have been found to induce liver damage in HF diet-fed rats. We therefore selected 5% chitosan oligosaccharide as an experimental object. Rats were divided into: a normal control diet group and a normal control diet +5% chitosan oligosaccharide group. The experimental period was 12 weeks. The results showed that supplementation of 5% chitosan oligosaccharide did not significantly change the body weight, food intake, liver/adipose tissue weights, plasma lipids, hepatic lipids, plasma levels of AST, ALT, and TNF-α/IL-6, hepatic lipid peroxidation and anti-oxidative enzyme activities, fecal lipids, and liver histomorphology in normal rats. These findings suggest that supplementation of 5% chitosan oligosaccharide for 12 weeks may not induce lipid metabolism disorder and liver toxicity in normal rats.

Comparative Effects and Mechanisms of Chitosan and Its Derivatives on Hypercholesterolemia in High-Fat Diet-Fed Rats

The present study investigated and compared the effects of different molecular weights of chitosan (high molecular weight chitosan (HC) and low molecular weight chitosan (LC)) and its derivatives (chitosan oligosaccharide (CO)) on cholesterol regulation in high-fat (HF) diet-fed rats. A diet supplementation of 5% HC, 5% LC, or 5% CO for 8 weeks showed hypocholesterolemic potential in HF diet-fed rats. Unexpectedly, a 5% CO-supplemented diet exerted hepatic damage, producing increased levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and tumor necrosis factor-alpha (TNF-α). The supplementation of HC and LC, unlike CO, significantly decreased the hepatic total cholesterol (TC) levels and increased the fecal TC levels in HF diet-fed rats. The hepatic protein expression of the peroxisome proliferator-activated receptor-α (PPARα) in the HF diet-fed rats was markedly decreased, which could be significantly reversed by both HC and LC, but not CO, supplementation. Unlike the supplementation of CO, both HC and LC supplementation could effectively reverse the HF-inhibited/induced gene expressions of the low-density lipoprotein receptor (LDLR) and cholesterol 7α-hydroxylase (CYP7A1), respectively. The upregulated intestinal acyl-CoA cholesterol acyltransferase 2 (ACAT2) protein expression in HF diet-fed rats could be reversed by HC and LC, but not CO, supplementation. Taken together, a supplementation of 5% CO in HF diet-fed rats may exert liver damage via a higher hepatic cholesterol accumulation and a higher intestinal cholesterol uptake. Both HC and LC effectively ameliorated the hypercholesterolemia and regulated cholesterol homeostasis via the activation and inhibition of hepatic (AMPKα and PPARα) and intestinal (ACAT2) cholesterol-modulators, respectively, as well as the modulation of downstream signals (LDLR and CYP7A1).

The Anti-Obesity Effect of Polysaccharide-Rich Red Algae (Gelidium amansii) Hot-Water Extracts in High-Fat Diet-Induced Obese Hamsters

This study investigated the anti-obesity effect of a polysaccharide-rich red algae Gelidium amansii hot-water extract (GHE) in high-fat (HF) diet-induced obese hamsters. GHE contained 68.54% water-soluble indigestible carbohydrate polymers. Hamsters were fed with a HF diet for 5 weeks to induce obesity, and then randomly divided into: HF group, HF with 3% guar gum diet group, HF with 3% GHE diet group, and HF with orlistat (200 mg/kg diet) group for 9 weeks. The increased weights of body, liver, and adipose in the HF group were significantly reversed by GHE supplementation. Lower plasma leptin, tumor necrosis factor-α, and interleukin-6 levels were observed in the GHE+HF group compared to the HF group. GHE also increased the lipolysis rate and decreased the lipoprotein lipase activity in adipose tissues. GHE induced an increase in the phosphorylation of AMP-activated protein kinase (AMPK) and the protein expressions of peroxisome proliferator-activated receptor alpha (PPARα) and uncoupling protein (UCP)-2 in the livers. The decreased triglyceride and total cholesterol in the plasma and liver were also observed in obese hamsters fed a diet with GHE. These results suggest that GHE exerts a down-regulation effect on hepatic lipid metabolism through AMPK phosphorylation and up-regulation of PPARα and UCP-2 in HF-induced obese hamsters.

Resistant Maltodextrin Ameliorates Altered Hepatic Lipid Homeostasis via Activation of AMP-Activated Protein Kinase in a High-Fat Diet-Fed Rat Model

Many studies have shown that resistant maltodextrin (RMD) possesses blood cholesterol lowering and anti-obesity effects. In order to investigate the effect of RMD on lipid metabolism in the liver, rats were fed with a high-fat (HF) diet for 7 weeks to induce hyperlipidemia and fatty liver. Normal control rats were fed with a normal diet. HF-diet-fed rats were treated with 5% RMD for 8 weeks. The results showed that the increased plasma aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities, the increased hepatic triglyceride and total cholesterol levels, and fatty liver in HF-diet-fed rats were significantly decreased after supplementation with RMD. Supplementation with RMD significantly (1) induced AMP-activated protein kinase (AMPK) phosphorylation; (2) inhibited the activities of acetyl-CoA carboxylase (ACC), fatty acid synthase (FAS), and HMG-CoA reductase (HMGCR); (3) suppressed the protein expression of peroxisome proliferator activated receptor (PPAR)-γ; (4) increased β-oxidation of fatty acids by increasing the protein expression carnitine palmitoyl transferase 1α (CPT-1α) in the livers of HF-diet-fed rats. Taken together, supplementation of RMD was capable of inhibiting lipogenic enzyme activities and inducing fatty acid β-oxidation through increasing AMPK activation, thereby reducing lipid accumulation in the liver.

Functional Comparison of High and Low Molecular Weight Chitosan on Lipid Metabolism and Signals in High-Fat Diet-Fed Rats

The present study examined and compared the effects of low- and high-molecular weight (MW) chitosan, a nutraceutical, on lipid metabolism in the intestine and liver of high-fat (HF) diet-fed rats. High-MW chitosan as well as low-MW chitosan decreased liver weight, elongated the small intestine, improved the dysregulation of blood lipids and liver fat accumulation, and increased fecal lipid excretion in rats fed with HF diets. Supplementation of both high- and low-MW chitosan markedly inhibited the suppressed phosphorylated adenosine monophosphate (AMP)-activated protein kinase-α (AMPKα) and peroxisome proliferator-activated receptor-α (PPARα) protein expressions, and the increased lipogenesis/cholesterogenesis-associated protein expressions [peroxisome proliferator-activated receptor-γ (PPARγ), sterol regulatory element binding protein-1c and -2 (SREBP1c and SREBP2)] and the suppressed apolipoprotein E (ApoE) and microsomal triglyceride transfer protein (MTTP) protein expressions in the livers of rats fed with HF diets. Supplementation with both a low- and high-MW chitosan could also suppress the increased MTTP protein expression and the decreased angiopoietin-like protein-4 (Angptl4) expression in the intestines of rats fed with HF diets. In comparison between low- and high-MW chitosan, high-MW chitosan exhibits a higher efficiency than low-MW chitosan on the inhibition of intestinal lipid absorption and an increase of hepatic fatty acid oxidation, which can improve liver lipid biosynthesis and accumulation.

Fish Oil Supplementation Alleviates the Altered Lipid Homeostasis in Blood, Liver, and Adipose Tissues in High-Fat Diet-Fed Rats

This study investigated the effects of dietary supplementation of fish oil on the signals of lipid metabolism involved in hepatic cholesterol and triglyceride influx and excretion in high-fat diet (HFD)-fed rats. Fish oil (FO) repressed body (HFD, 533 ± 18.2 g; HFD+FO, 488 ± 28.0 g, p < 0.05) and liver weights (HFD, 5.7 ± 0.6 g/100 g of body weight; HFD+FO, 4.8 ± 0.4 g/100 g of body weight, p < 0.05) in HFD-fed rats. Fish oil could also improve HFD-induced imbalance of lipid metabolism in blood, liver, and adipose tissues including the significant decreases in plasma and liver total cholesterol (TC) (plasma-HFD, 113 ± 33.6 mg/dL; HFD+FO, 50.0 ± 5.95 mg/dL, p < 0.05; liver-HFD, 102 ± 13.0 mg/g liver; [corrected] HFD+FO, 86.6 ± 7.81 mg/g liver, [corrected] p < 0.05), blood, liver, and adipose triglyceride (TG) (blood-HFD, 52.5 ± 20.4 mg/dL; HFD+FO, 29.8 ± 4.30 mg/dL, p < 0.05; liver-HFD, 56.2 ± 10.0 mg/g liver; [corrected] HFD+FO, 30.3 ± 5.28 mg/g liver, [corrected] p < 0.05; adipose-HFD, 614 ± 73.2 mg/g liver, [corrected] HFD+FO, 409 ± 334 mg/g of adipose tissue, [corrected] p < 0.05), and low density (HFD, 79.8 ± 40.9 mg/dL; HFD+FO, 16.6 ± 5.47 mg/dL, p < 0.05) and very-low-density (HFD, 49.7 ± 33.3 mg/dL; HFD+FO, 10.4 ± 3.45 mg/dL, p < 0.05) lipoprotein and the significant increases in fecal TC (HFD, 12.2 ± 0.67 mg/g feces; [corrected] HFD+FO, 16.3 ± 2.04 mg/g feces, [corrected] < 0.05) and TG (HFD, 2.09 ± 0.10 mg/g feces; [corrected] HFD+FO, 2.38 ± 0.22 mg/g feces, [corrected] p < 0.05) and lipoprotein lipase activity of adipose tissues (HFD, 16.6 ± 3.64 μM p-nitrophenol; HFD+FO, 24.5 ± 4.19 μM p-nitrophenol, p < 0.05). Moreover, fish oil significantly activated the protein expressions of hepatic lipid metabolism regulators (AMPKα and PPARα) and significantly regulated the lipid-transport-related signaling molecules (ApoE, MTTP, ApoB, Angptl4, ApoCIII, ACOX1, and SREBPF1) in blood or liver of HFD-fed rats. These results suggest that fish oil supplementation improves HFD-induced imbalance of lipid homeostasis in blood, liver, and adipose tissues in rats.

Long-term feeding of red algae ( Gelidium amansii ) ameliorates glucose and lipid metabolism in a high fructose diet-impaired glucose tolerance rat model

This study was designed to investigate the effect of Gelidium amansii (GA) on carbohydrate and lipid metabolism in rats with high fructose (HF) diet (57.1% w/w). Five-week-old male Sprague-Dawley rats were fed a HF diet to induce glucose intolerance and hyperlipidemia. The experiment was divided into three groups: (1) control diet group (Con); (2) HF diet group (HF); and (3) HF with GA diet group (HF + 5% GA). The rats were fed the experimental diets and drinking water ad libitum for 23 weeks. The results showed that GA significantly decreased retroperitoneal fat mass weight of HF diet-fed rats. Supplementation of GA caused a decrease in plasma glucose, insulin, tumor necrosis factor-α, and leptin. HF diet increased hepatic lipid content. However, intake of GA reduced the accumulation of hepatic lipids including total cholesterol (TC) and triglyceride contents. GA elevated the excretion of fecal lipids and bile acid in HF diet-fed rats. Furthermore, GA significantly decreased plasma TC, triglyceride, low density lipoprotein plus very low density lipoprotein cholesterol, and TC/high density lipoprotein cholesterol ratio in HF diet-fed rats. HF diet induced an in plasma glucose and an impaired glucose tolerance, but GA supplementation decreased homeostasis model assessment equation-insulin resistance and improved impairment of glucose tolerance. Taken together, these results indicate that supplementation of GA can improve the impairment of glucose and lipid metabolism in an HF diet-fed rat model.

Vegetable, fruit, and phytonutrient consumption patterns in Taiwan

Phytonutrients may play important roles in human health and yet only recently a few studies have described phytonutrient consumption patterns, using data obtained from daily consumption methods. We aimed to estimate the phytonutrient content in Taiwanese diets and analyzed main food sources of 10 major phytonutrients. In this study, food items and dietary data gathered with the 24-hour dietary recall from 2908 participants in the 2005–2008 Nutrition and Health Survey in Taiwan were used to create a food phytonutrient database with 933 plant-based foods through integrating database, literature search, and chemical analysis and to appraise phytonutrient consumption status of participants. SUDAAN (Survey Data Analysis) was used for generating weighted phytonutrient intake estimates and for statistical testing. In Taiwanese adults, ~20% met the recommended number of servings for fruits and 30% met that for vegetables from the Taiwan Food-Guide recommendations. However, only 7.4% consumed the recommended numbers for both fruits and vegetables. Those meeting the recommendations tended to be older and with more females compared with those who did not. Phytonutrient intake levels were higher in meeters than nonmeeters. More than 60% of α-carotene, lycopene, hesperetin, epigallocatechin 3-gallate, and isoflavones came from a single phytonutrient-specific food source. In addition, sweet potato leaf, spinach, and water spinach were among the top three sources of multiple phytonutrients. Cross-comparison between this study and two previous studies with similar methodology showed higher mean levels of lycopene and quercetin in the United States, anthocyanidins in Korea, and lutein and zeaxanthin in Taiwan. The Taiwanese phytonutrient pattern is different from that of the Korean and American. It would be interesting to relate phytonutrient patterns to health profiles in the future.

Red algae (Gelidium amansii) hot-water extract ameliorates lipid metabolism in hamsters fed a high-fat diet

The purpose of this study was to investigate the effects of Gelidium amansii (GA) hot-water extracts (GHE) on lipid metabolism in hamsters. Six-week-old male Syrian hamsters were used as the experimental animals. Hamsters were divided into four groups: (1) control diet group (CON); (2) high-fat diet group (HF); (3) HF with GHE diet group (HF + GHE); (4) HF with probucol diet group (HF + PO). All groups were fed the experimental diets and drinking water ad libitum for 6 weeks. The results showed that GHE significantly decreased body weight, liver weight, and adipose tissue (perirenal and paraepididymal) weight. The HF diet induced an increase in plasma triacylglycerol (TG), total cholesterol (TC), low-density lipoprotein cholesterol and very-low-density lipoprotein cholesterol levels. However, GHE supplementation reversed the increase of plasma lipids caused by the HF diet. In addition, GHE increased fecal cholesterol, TG and bile acid excretion. Lower hepatic TC and TG levels were found with GHE treatment. GHE reduced hepatic sterol regulatory element-binding proteins (SREBP) including SREBP 1 and SREBP 2 protein expressions. The phosphorylation of adenosine monophosphate (AMP)-activated protein kinase (AMPK) protein expression in hamsters was decreased by the HF diet; however, GHE supplementation increased the phosphorylation of AMPK protein expression. Our results suggest that GHE may ameliorate lipid metabolism in hamsters fed a HF diet.

γ-Synuclein Expression Is a Malignant Index in Oral Squamous Cell Carcinoma

Dysregulation of γ-synuclein (SNCG) has been reported in many cancers; however, its role in cancer development is still controversial. Here, we examined the potential involvement of DNA methylation in regulating SNCG and its role in oral squamous cell carcinoma (OSCC). We used 8 OSCC cell lines to investigate SNCG methylation and expression. SNCG methylation was examination by methylation-specific polymerase chain reaction and bisulfate sequencing. Cells showing a high degree of SNCG methylation were treated with 5-aza (methylation inhibitor), and changes in their methylation and expression profiles were analyzed. Functional effects of SNCG in OSCC were examined by its overexpression and knockdown. Additionally, methylation and expression of SNCG in OSCC tissues were investigated and correlated with clinicopathologic features. All OSCC cells showed detectable SNCG expression at the mRNA and protein levels. Methylation-specific polymerase chain reaction and bisulfate sequencing revealed high SNCG expression in SCC25 cells with the unmethylated allele, and their 15 CpG islands were unmethylated. The methylated allele was detected only in OEC-M1 cells exhibiting low SNCG expression, and their CpG islands were partially methylated. 5-aza treatment in OEC-M1 cells attenuated methylation and restored SNCG expression. SNCG overexpression increased colony forming, migration, and invasion abilities in OEC-M1 cells. Silencing SNCG in SCC25 cells suppressed these behaviors. All 25 tumor-adjacent normal tissues were negative for SNCG immunostaining. SNCG upregulation was frequently observed in dysplastic and OSCC tissues. Positive SNCG expression was found in 45% (37 of 82) OSCC tissues. Positive SNCG expression in OSCC significantly correlated with cancer staging and lymph node metastasis. However, SNCG methylation did not correlate with its expression and clinicopathologic variables in OSCC tissues. DNA methylation may participate in regulating SNCG expression in some OSCC cells. SNCG upregulation could be involved in OSCC progression.

Long-Term Feeding of Chitosan Ameliorates Glucose and Lipid Metabolism in a High-Fructose-Diet-Impaired Rat Model of Glucose Tolerance

This study was designed to investigate the effects of long-term feeding of chitosan on plasma glucose and lipids in rats fed a high-fructose (HF) diet (63.1%). Male Sprague-Dawley rats aged seven weeks were used as experimental animals. Rats were divided into three groups: (1) normal group (normal); (2) HF group; (3) chitosan + HF group (HF + C). The rats were fed the experimental diets and drinking water ad libitum for 21 weeks. The results showed that chitosan (average molecular weight was about 3.8 × 10⁵ Dalton and degree of deacetylation was about 89.8%) significantly decreased body weight, paraepididymal fat mass, and retroperitoneal fat mass weight, but elevated the lipolysis rate in retroperitoneal fats of HF diet-fed rats. Supplementation of chitosan causes a decrease in plasma insulin, tumor necrosis factor (TNF)-α, Interleukin (IL)-6, and leptin, and an increase in plasma adiponectin. The HF diet increased hepatic lipids. However, intake of chitosan reduced the accumulation of hepatic lipids, including total cholesterol (TC) and triglyceride (TG) contents. In addition, chitosan elevated the excretion of fecal lipids in HF diet-fed rats. Furthermore, chitosan significantly decreased plasma TC, low-density lipoprotein cholesterol (LDL-C), very-low-density lipoprotein cholesterol (VLDL-C), the TC/high-density lipoprotein cholesterol (HDL-C) ratio, and increased the HDL-C/(LDL-C + VLDL-C) ratio, but elevated the plasma TG and free fatty acids concentrations in HF diet-fed rats. Plasma angiopoietin-like 4 (ANGPTL4) protein expression was not affected by the HF diet, but it was significantly increased in chitosan-supplemented, HF-diet-fed rats. The high-fructose diet induced an increase in plasma glucose and impaired glucose tolerance, but chitosan supplementation decreased plasma glucose and improved impairment of glucose tolerance and insulin tolerance. Taken together, these results indicate that supplementation with chitosan can improve the impairment of glucose and lipid metabolism in a HF-diet-fed rat model.

Red algae (Gelidium amansii) reduces adiposity via activation of lipolysis in rats with diabetes induced by streptozotocin-nicotinamide

Gelidium amansii (GA) is an edible red algae that is distributed mainly in northeastern Taiwan. This study was designed to investigate the effects of GA on plasma glucose, lipids, and adipocytokines in rats with streptozotocin-nicotinamide-induced diabetes. Rats were divided into four groups: (1) rats without diabetes fed a high-fat diet (control group); (2) rats with diabetes fed a high-fat diet; (3) rats with diabetes fed a high-fat diet with thiazolidinedione in the diet; and (4) rats with diabetes fed a high-fat diet and GA. The experimental diet and drinking water were available ad libitum for 11 weeks. After the 11-week feeding study, plasma glucose, triglyceride, and cholesterol concentrations were lower in rats with diabetes fed the GA diet than in animals with diabetes fed the control diet. In addition, cholesterol and triglyceride excretion were significantly higher in rats with diabetes fed the GA diet. Moreover, GA feeding induced lipolysis in both paraepididymal and perirenal adipose tissues. Adipose tissue (paraepididymal and perirenal) weight and triglyceride contents were lower after GA treatment. Plasma adipocytokines including tumor necrosis factor-alpha, interleukin-6, and plasminogen activator inhibitor-1 were reduced by GA feeding in rats with diabetes. The results of the current study suggest that GA feeding may regulate plasma glucose and lipid levels and prevent adipose tissue accumulation in rats with diabetes.

Supplementation of chitosan alleviates high-fat diet-enhanced lipogenesis in rats via adenosine monophosphate (AMP)-activated protein kinase activation and inhibition of lipogenesis-associated genes

This study investigated the role of chitosan in lipogenesis in high-fat diet-induced obese rats. The lipogenesis-associated genes and their upstream regulatory proteins were explored. Diet supplementation of chitosan efficiently decreased the increased weights in body, livers, and adipose tissues in high-fat diet-fed rats. Chitosan supplementation significantly raised the lipolysis rate; attenuated the adipocyte hypertrophy, triglyceride accumulation, and lipoprotein lipase activity in epididymal adipose tissues; and decreased hepatic enzyme activities of lipid biosynthesis. Chitosan supplementation significantly activated adenosine monophosphate (AMP)-activated protein kinase (AMPK) phosphorylation and attenuated high-fat diet-induced protein expressions of lipogenic transcription factors (PPAR-γ and SREBP1c) in livers and adipose tissues. Moreover, chitosan supplementation significantly inhibited the expressions of downstream lipogenic genes (FAS, HMGCR, FATP1, and FABP4) in livers and adipose tissues of high-fat diet-fed rats. These results demonstrate for the first time that chitosan supplementation alleviates high-fat diet-enhanced lipogenesis in rats via AMPK activation and lipogenesis-associated gene inhibition.

Effects of long-term feeding of chitosan on postprandial lipid responses and lipid metabolism in a high-sucrose-diet-impaired glucose-tolerant rat model

This study was designed to investigate the effects of long-term feeding of chitosan on postprandial lipid response and lipid metabolism in a high-sucrose (HS)-diet-impaired glucose-tolerant rat model. As the results, HS-diet-fed rats supplemented with 5 and 7% chitosan in diets for 9 weeks had lower postprandial plasma total cholesterol (TC) levels, but 7% chitosan in the diet had higher postprandial plasma triglyceride (TG) and TG-rich lipoprotein TG levels. Supplementation of chitosan significantly decreased the postprandial ratio of apolipoprotein B (apoB)48/apoB100 in TG-rich lipoprotein fractions of HS-diet-fed rats. Long-term supplementation of 5 and 7% chitosan in diets for 16 weeks had lower plasma TC, low-density lipoprotein cholesterol (LDL-C) + very low density lipoprotein cholesterol (VLDL-C), TC/high-density lipoprotein (HDL-C) ratio, leptin, and tumor necrosis factor-α (TNF-α) levels in HS-diet-fed rats. Moreover, it was noticed that the VLDL receptor (VLDLR) protein expression in skeletal muscles of HS-diet-fed rats was significantly decreased, which could be significantly reversed by supplementation of 5 and 7% chitosan. Rats supplemented with 7% chitosan in the diet significantly elevated the lipolysis rate and decreased the accumulation of TG in epididymal fat pads of HS-diet-fed rats. The plasma angiopoietin-like 4 (ANGPTL4) protein expression was not affected in HS-diet-fed rats, but it was significantly increased in 7% chitosan-supplemented HS-diet-fed rats. Taken together, these results indicate that supplementation of chitosan in the diet can improve the impairment of lipid metabolism in a HS-diet-fed rat model, but long-term high-dose chitosan feeding may enhance postprandial plasma TG and TG-rich lipoprotein TG levels in HS-diet-fed rats through an ANGPTL4-regulated pathway.

Effects of chitosan oligosaccharides on drug-metabolizing enzymes in rat liver and kidneys

To investigate the effect of chitosan oligosaccharides (COS) on drug-metabolizing enzymes in rat liver and kidneys, male Spraque-Dawley rats were fed a diet containing 1% or 3% COS for 5 weeks. The activities of cytochrome P450 (CYP) enzymes, UDP-glucurosyltransferase (UGT) and glutathione S-transferase (GST) in the liver and kidneys were determined. Significant decreases in microsomal CYP3A-catalyzed testosterone 6β-hydroxylation, CYP2C-catalyzed diclofenac 4-hydroxylation, and CYP4A-catalyzed lauric acid 12-hydroxylation in the liver of rats fed the COS diets were observed compared with those rats fed the control diet. Immunoblot analyses of CYP proteins showed the same trend as with enzyme activities. Increased glutathione content in liver was found in rats fed the 1% COS diet. Increased hepatic NADPH: quinone oxidoreductase 1 (NQO1) activity was found in rats fed the COS diets. In kidneys, COS had little or no effect on CYP enzyme activities. However, increased GST activity was observed in rats fed the COS diets. Moreover, a higher UGT activity was found in rats fed the 1% COS diet. Our results indicate that COS may suppress hepatic CYP enzymes and induce phase II detoxifying reactions in the liver and kidneys of rats.

Suppressive effect of the ethanolic extract of adlay bran on cytochrome P-450 enzymes in rat liver and lungs

Adlay ( Coix lachryma-jobi L. var. ma-yuen Stapf) is a grass crop and is reported to protect against various diseases such as cancer. To investigate the effect of the ethanolic extract of adlay bran (ABE) on drug-metabolizing enzymes and glutathione-related antioxidant enzymes in rats, three groups of eight male Sprague-Dawley rats each were fed a control diet or a diet containing 5 or 10% ABE for 4 weeks. Significant decreases in microsomal cytochrome P-450 (CYP) 1A1-catalyzed ethoxyresorufin O-deethylation, CYP2C-catalyzed diclofenac 4-hydroxylation, CYP2D-catalyzed dextromethorphan O-demethylation, and CYP3A-catalyzed testosterone 6β-hydroxylation in the liver and CYP1A1-catalyzed ethoxyresorufin O-deethylation in the lungs of rats fed ABE were observed. Immunoblot analyses also showed decreases of CYP1A1, 1A2, 2C6, 2C11, 2D1, 2E1, 3A1, and 3A2 in the liver and CYP1A1 in the lungs. Furthermore, rats fed the 10% ABE diet had a higher glutathione content and glutathione peroxidase, glutathione reductase, and glutathione S-transferase activities in the lungs, but such an increase was not noted in the liver. Inhibition of various CYP-catalyzed enzyme reactions by ABE in rat and human liver microsomes had also been shown. The results of this study indicate that ABE feeding may suppress CYP enzyme activities and CYP protein expression in the liver and lungs of rats. Moreover, the increase of the antioxidant potential by ABE is tissue-specific.

Chitosan reduces gluconeogenesis and increases glucose uptake in skeletal muscle in streptozotocin-induced diabetic rats

Chitosan is a natural and versatile biomaterial with a blood-glucose-lowering effect in diabetic animals, but the mechanism of action is still unknown. This study was designed to investigate the possible mechanisms involved in the hypoglycemic activity of chitosan in rats with streptozotocin (STZ)-induced diabetes. Male Sprague-Dawley (SD) rats were divided into non-diabetic with cellulose (control), diabetic with cellulose (DM), and diabetic with low- (DM + LCS) and high- (DM + HCS) molecular-weight chitosan groups. After a 4 week feeding study, plasma glucose and fructosamine levels were increased while plasma leptin was decreased in the DM group when compared to the control group. These alternations caused by diabetes could be effectively reversed by both chitosan treatments. The increased gluconeogenesis-related signals including phosphoenolpyruvate carboxykinase (PEPCK) expression and phosphorylations of p38 and AMP-activated kinase (AMPK) in the livers of diabetic rats were attenuated by chitosans. Moreover, chitosan significantly increased muscle glucose uptake-related signals including Akt phosphorylation and glucose transporter-4 (GLUT4) translocation from the cytosol to membrane in the soleus muscles of diabetic rats. These results indicate that chitosan may possess a potential for alleviating type-1 diabetic hyperglycemia through the decrease in liver gluconeogenesis and increase in skeletal muscle glucose uptake and use.

Effect of chitosan on hepatic drug-metabolizing enzymes and oxidative stress in rats fed low- and high-fat diets

Chitosan is sold worldwide as a lipid-lowering functional food and may be taken with certain medications. To investigate the effect of chitosan on drug-metabolizing enzymes and oxidative stress in the liver, male Wistar rats were fed a low- or high-fat diet with cellulose or chitosan for 4 weeks. A significant decrease in cytochrome P450 (CYP) 3A-catalyzed testosterone 6beta-hydroxylation in liver microsomes was observed in rats fed the chitosan with low- and high-fat diets. The expression of CYP 3A1 and 3A2, however, was suppressed by chitosan in rats fed the low-fat diet only. Furthermore, rats fed the low-fat diet with chitosan had lower hepatic glutathione S-transferase (GST) activity and superoxide dismutase activity and higher total tissue and microsomal lipid hydroperoxides. Hepatic alpha-tocopherol was lower in rats fed the chitosan-containing diet. The results suggest that chitosan is likely to modulate CYP 3A activity and protein expression and GST activity partially in a dietary fat-dependent manner. This change may cause a decrease in the metabolism of drugs catalyzed by these enzymes in liver tissues. Moreover, decrease of alpha-tocopherol level and SOD activity by chitosan partly accounts for the increase of hepatic lipid peroxidation.

Shengmai San reduces hepatic lipids and lipid peroxidation in rats fed on a high-cholesterol diet

Shengmai San (SMS), which is comprised of the medicinal herbs of Panax ginseng C.A. Meyer, Schisandra chinensis Baill., and Ophiopogon japonicus Ker-Gawl (2:1:2)., is a traditional Chinese medicine being used for treating coronary heart disease. The aim of this study was to investigate the effects of SMS on the plasma and liver lipids, lipid peroxidation and antioxidant systems in liver and heart of cholesterol-fed rats. Rats were fed on a high-cholesterol (0.5%) diet (control group), high-cholesterol diet containing 2% SMS (2% SMS group) and 4% SMS (4% SMS group) for four weeks. The oxidative stress marker (thiobarbituric acid reactive substances, TBARS) and antioxidant defense systems including glutathione (GSH), glutathione peroxidase (GSH-Px), glutathione-S-transferase (GST) and superoxide dismutase (SOD) activities in rat liver and heart were evaluated. Results showed that rats fed with SMS-containing diet had reduced the H(2)O(2)-induced erythrocytes susceptibility to hemolysis, and 4% SMS feeding rats had higher plasma GSH concentration compared to the animals fed with the control diet. However, SMS had no effect on plasma lipids (total cholesterol, triglyceride and high-density lipoprotein cholesterol) and TBARS concentration. On the other hand, rats fed with the 4% SMS diet reduced the hepatic cholesterol and triglyceride contents. Fecal bile acid excretion was significantly increased in rats fed with the SMS-containing diet. Higher hepatic GSH and lower TBARS concentrations were observed in rats fed with the 4% SMS diet compared with the rats fed with the control diet. No significant difference in activities of GSH-Px, GST and SOD was found in liver and heart after the SMS treatment. Results from this study indicate that the SMS may reduce hepatic lipids and lipid peroxidation in rats.

A comparative study on hypoglycemic and hypocholesterolemic effects of high and low molecular weight chitosan in streptozotocin-induced diabetic rats

The hypoglycemic and hypocholesterolemic effects of high and low molecular weight chitosan were evaluated in streptozotocin (STZ)-induced diabetic rats. Rats were divided into three groups of normal rats (Experiment I) and three groups of diabetic rats (Experiment II). The first group received a cellulose (control) diet, the second group received a low MW (1.4 x 10(4)Da) chitosan diet and the third group received a high MW (1.0 x 10(6)Da) chitosan diet. All three diets were containing 0.5% cholesterol. Experiment I: rats fed with high MW or low MW chitosan diet had increased high density lipoprotein (HDL) cholesterol. However, chitosan did not affect plasma glucose in normal rats. Experiment II: significantly decreased plasma glucose and total cholesterol and increased HDL cholesterol and fecal cholesterol excretion were observed in diabetic rats fed with high MW chitosan diet than animals fed with cellulose diet. However, no statistical significant difference in plasma glucose and total cholesterol was observed in diabetic rats fed with low MW chitosan. The total content of SCFAs in cecum was significantly increased and the ratio of acetate to propionate was slight but significantly decreased in diabetic rats after consuming high MW chitosan diet. The activities of hepatic hexokinase were significantly increased and the intestinal disaccharidases including sucrase and maltase were significantly decreased in normal and diabetic rats fed with high MW chitosan diet. Results obtained from the present study demonstrated the potential of high MW chitosan in reducing hyperglycemia and hypercholesterolemia in STZ-induced diabetic rats.

Apocynin alleviated hepatic oxidative burden and reduced liver injury in hypercholesterolaemia

BACKGROUND

This study addressed the effects of apocynin, a nicotinamide adenine dinucleotide phosphate (NADPH) oxidase inhibitor, on hepatic oxidative burden and liver injury during diet-induced hypercholesterolaemia.

METHODS AND RESULTS

Male Wistar rats were fed a 4% cholesterol-enriched diet for 3 weeks. Apocynin was administered in drinking water concurrently. The high-cholesterol diet (HC) significantly increased the serum level of cholesterol and hepatic cholesterol ester deposition, and these parameters were similar between the HC and high-cholesterol diet plus apocynin (HCA) groups. The HC group showed abnormal liver function tests [alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (Alk-P)] as well as increased Evans blue extravasation and macrophages infiltration. Apocynin treatment could suppress these inflammation-related parameters. In vivo measurement of NADPH-derived cellular autofluorescence suggested that HC increased oxidative stress in hepatocytes. Biochemical analysis of redox status including thiobarbituric acid reactive substances, reduced glutathione, and oxidized glutathione also confirmed the phenomenon. Apocynin treatment was able to alleviate these indices of oxidative burden owing to HC. Furthermore, apocynin-abrogated HC induced gp91(phox) expression, suggesting the involvement of NADPH oxidase in the pathogenesis.

CONCLUSIONS

We concluded that apocynin suppressed NADPH oxidase activation and subsequent liver injuries owing to high-cholesterol intake in rats. The impacts of cholesterol metabolism disorders on pathogenesis and progression of steatohepatitis warrant further clinical investigation.

Effects of Dehulled Adlay on Plasma Glucose and Lipid Concentrations in Streptozotocin-induced Diabetic Rats fed a Diet Enriched in Cholesterol

Adlay (Coix lachryma-jobi L. var. ma-yuen Stapf) is a cereal food for humans and has been also used as a superior medical herb substance and functional food for traditional treatment of diabetes in China. However, its scientific basis as a functional food is still unclear. The purpose of this study was to investigate the effect of dietary dehulled adlay on plasma lipid and glucose concentrations in diabetic rats. The diabetic male Sprague-Dawley (SD) rats, induced by injection of streptozotocin (60 mg/kg subcutaneously), were fed a cholesterol-rich diet (0.5% cholesterol) containing corn starch or dehulled adlay for four weeks. After completion of the experimental period, the abdominal adipose tissue and liver of rats were excised and weighed, and the plasma glucose, triglyceride, and lipoprotein cholesterol concentrations were assayed. The results showed that diabetic rats fed a dehulled adlay diet exhibited a greater adipose tissue weight (9.36 ± 3.43 vs. 5.39 ± 3.04 g, p < 0.05) and a reduced food intake (39.3 ± 5.9 vs. 61.0 ± 11.7 g/day, p < 0.05) when compared with animals fed a cornstarch diet. Significantly decreased plasma glucose (261.6 ± 96.6 vs. 422.1 ± 125.4 mg/dL, p < 0.05), total cholesterol (289.4 ± 140.6 vs. 627.3 ± 230.5 mg/dL, p < 0.05), and triglyceride (52.3 ± 14.4 vs. 96.5 ± 36.6 mg/dL, p < 0.05) levels were observed in rats fed the dehulled adlay diet. In addition, the ingestion of dehulled adlay appears to significantly decrease plasma low-density lipoprotein (LDL) plus very low-density lipoprotein (VLDL) cholesterol concentrations. Rats fed a dehulled adlay diet showed an increase in fecal weight and cholesterol contents of stools. Although a significantly decreased plasma thiobarbituric reactive substances (TBARS) value was observed in diabetic rats fed the dehulled adlay diet (6.2 ± 3.4 vs. 11.0 ± 3.8 nmol malondialdehyde (MDA)/mL, p < 0.05), no significant difference in the hepatic TBARS value was observed between the two dietary groups. Results from the present study suggest that dehulled adlay exhibited not only a hypolipidemic effect but also displayed a hypoglycemic ability in diabetic rats, indicating that dehulled adlay may play an important role in the regulation of plasma lipid and glucose metabolisms in diabetic rats induced by streptozotocin.

Chitosan Shifts the Fermentation Site Toward the Distal Colon and Increases the Fecal Short-Chain Fatty Acids Concentrations in Rats

Chitosan has been shown to have lipid-lowering effects, but little is known about the effect of chitosan on colonic pH value and short-chain fatty acid (SFCA) concentration. This study was designed to investigate the effect of chitosan on colonic bacterial fermentation and fecal bacterial enzyme activity in rats fed a diet enriched in cholesterol. Male Sprague-Dawley rats were fed a diet containing 5% cellulose (CE) or 5% chitosan (CS) for 15 days. Significantly increased fecal cholesterol and triacylglycerols contents were observed in rats fed the chitosan diet. In addition, lower cecal acetate and butyrate concentrations and higher fecal acetate, propionate, and butyrate concentrations were observed in rats fed the CS diet when compared to those fed the CE diet. Although rats fed with the CS diet exhibited an elevated cecal (cecum with contents) weight and higher pH value, no significant difference in fecal pH value was observed between the CE group and the CS group. Chitosan significantly decreased fecal mucinase and beta-glucuronidase activities. Results from this study show that chitosan may alter fecal bacterial enzyme activities and SCFA concentrations and the beneficial effects of chitosan on the colonic environment may occur in the distal colon in rats.

The effect of adlay oil on plasma lipids, insulin and leptin in rat

This study was designed to investigate the effect of dietary adlay oil on plasma lipids, insulin and lipid peroxidation levels in rats. Twenty-four male Wistar rats fed diet containing adlay oil and cholesterol were studied for 4 weeks. The animals were divided into three groups: (1) 10% lard (control) group; (2) 5% lard + 5% adlay oil (5% adlay oil) group; and (3) 10% adlay oil group. Although there was no significant difference in body weight at the end of the feeding study, rats fed a diet containing adlay oil showed a significant decrease in adipose tissue weight and relative adipose weight. In addition, the rats fed the adlay oil showed significantly decreased low-density lipoprotein cholesterol (LDL-C), insulin, leptin and thiobarbituric acid reactive substance (TBARS) concentrations after 4 weeks of the feeding study. Although a significant decrease in total plasma cholesterol was observed in rats fed the 5% adlay oil diet, no significant difference was observed between the 10% adlay oil and control groups, and neither was a significant difference in liver TBARS concentration found between the dietary groups. Results from this study suggest that dietary adlay oil can reduce leptin, adipose tissue and LDL-C levels in rats.

Plasma lipoprotein cholesterol in rats fed a diet enriched in chitosan and cholesterol

To investigate the effect of dietary chitosan on plasma lipoprotein cholesterol metabolism, male Sprague-Dawley (SD) rats fed a cholesterol-enriched diet containing cellulose (CE) or chitosan (CS) were studied for 2 wk. Lower plasma total cholesterol, low-density lipoprotein (LDL) cholesterol and very-low-density lipoprotein (VLDL) cholesterol were observed in rats fed a diet containing chitosan. In addition, significantly higher high-density lipoprotein (HDL) cholesterol and HDL2 cholesterol were observed in rats after 2 wk of chitosan feeding. Rats fed the chitosan diet had increased triacylglycerol percentages and decreased free cholesterol, cholesteryl ester and phospholipid percentages in VLDL lipid composition. Chitosan significantly decreased the surface lipid proportions and increased the core lipid proportions in VLDL particles. In addition, the ratios of surface lipids to core lipids of the VLDL particles in rats fed a diet containing chitosan were significantly decreased. A significantly lower plasma apolipoprotein B (Apo B) concentration was observed in rats fed the chitosan diet as compared to those fed the cellulose diet. No significant difference in plasma triacylglycerols or glucose levels was observed between the two dietary groups. Results from this study suggest that chitosan may alter the VLDL particle size and also play an important role in the regulation of lipoprotein metabolism in rats.

Tris(2,2'-bipyridyl)ruthenium(III)-based electrochemiluminescence detector with indium/tin oxide working electrode for capillary electrophoresis

A novel tris(2,2'-bipyridyl)ruthenium(III) [Ru(bpy)3(3+)]-based electrochemiluminescence (ECL) detector for capillary electrophoresis (CE) has been developed. The detector was of the wall-jet configuration and an indium/tin oxide (ITO)-coated glass plate was used as the working electrode for end-column detection. Potential control of the ITO electrode was provided using a DC battery, without decoupling the detector from the CE field. Electrochemical behavior of Ru(bpy)3(2+) at the ITO electrode was found to be analogous to that at a Pt electrode. In the presence of tertiary or some secondary amines, ECL emission due to reaction between in situ generated Ru(bpy)3(3+) and analytes can be observed at the ITO surface. With 15 mM sodium borate (pH 9.5) plus 1 mM Ru(bpy)3(2+) present in the detection cell and the ITO electrode biased at 1.5 V (vs. Pt wire reference), a detection limit of 1 microM proline with a theoretical plate number of 4000 was obtained using the developed CE-ECL detection system. The detector response was found to be analyte-dependent, e.g. tryptophan gives no response, and the response for histidine is about 13-fold lower than that of proline.

Chiral analysis of baclofen by alpha-cyclodextrin-modified capillary electrophoresis and laser-induced fluorescence detection

An enantioselective method for baclofen (4-amino-3-p-chlorophenylbutyric acid) based on capillary electrophoresis (CE) separation and laser-induced fluorescence (LIF) detection has been developed. Naphthalene-2,3-dicarboxaldehyde (NDA) was used for precolumn derivatization of the nonfluorescent drug. alpha-Cyclodextrin (alpha-CD) was included in the buffer as a chiral selector for the separation of NDA-labeled S-(+)- and R-(-)-baclofen. Optimal resolution and detection were obtained with an electrophoretic buffer of 50 mM sodium borate (pH 9.5) containing 7 mM alpha-CD and a He-Cd laser (lambda ex = 442 nm, lambda em = 500 nm). Combined with a simple cleanup procedure, this method can be applied to the analysis of baclofen enantiomers in human plasma. The relative standard deviation (RSD) values on peak areas of a plasma sample containing 1.0 microM racemic baclofen were 6.4 and 4.9% (n = 8) for the S-(+)- and R-(-)-enantiomer, respectively. The RSD value on migration times of both enantiomers was 0.5% (n = 8). Calibration graphs for S-(+)- and R-(-)-baclofen in plasma showed a good linearity (r > or = 0.999) in the concentration range of 0.1-2.0 microM. The limit of detection of baclofen in plasma was about 10 ng/mL.

Effect of dietary chitosans with different viscosity on plasma lipids and lipid peroxidation in rats fed on a diet enriched with cholesterol

To investigate the effect of dietary chitosan on lipid metabolism, male SD (Sprague-Dawley) rats were fed a cholesterol-enriched diet containing 5% cellulose (CE), 5% chitosan (CCS; high viscosity), or 5% chitosan (FCS; low viscosity) for 4 weeks. The two types of chitosan with a comparable degree of deacetylation had a different molecular weight and intrinsic viscosity. Significantly (p < 0.05) lower plasma total cholesterol, LDL-cholesterol and VLDL-cholesterol concentrations were observed in the rats fed on the chitosan diets. In addition, chitosan significantly increased the fecal cholesterol and triglyceride contents. Although no significant difference in body weight was found among the dietary groups, the rats fed on the chitosan diets had lower relative liver weight when compared with those fed on the cellulose diet. Both of the chitosan groups had significantly lower liver total lipid and total cholesterol contents compared to the cellulose group, although the FCS group was less effective. The plasma and liver thiobarbituric acid reactive substances (TBAR) values were similar in the CE and FCS groups, while the CCS group had increased liver TBAR values. Although a significant increase in liver glucose-6-phosphate dehydrogenase activity was observed in the CCS group, no significant change was found in the FCS group. The observed influence of chitosans with different viscosity on the plasma lipid level, liver lipids and lipid peroxidation suggests that, while the hypocholesterolemic action of chitosans with different viscosity was similar, changes in the liver lipids and liver peroxidation status depended on their molecular weight when the deacetylation degree was comparable.

Analysis of baclofen by capillary electrophoresis with laser-induced fluorescence detection

A new analytical method for baclofen (4-amino-3-p-chlorophenylbutyric acid) based on capillary electrophoretic separation and laser-induced fluorescence detection has been developed. Naphthalene-2,3-dicarboxaldehyde was used for precolumn derivatization of the non-fluorescent drug. Optimal separation and detection were obtained with an electrophoretic buffer of 50 mM sodium borate (pH 9.5) and a He-Cd laser (excitation at 442 nm, emission at 500 nm). Linearity (r > or = 0.99) over three orders of magnitude was generally obtained and the concentration limit of detection was in the nanomolar level. Coupled with a simple cleanup procedure, the method was successfully applied to the analysis of baclofen in human plasma. Recovery of spiked baclofen in plasma was 98%. The relative standard deviation values on peak size and migration time were 7.9% and 0.4%, respectively. The limit of detection of baclofen in plasma was 10 ng/ml.

Effect of dietary vitamin E on antioxidant status and antioxidant enzyme activities in Sprague-Dawley rats

The effect of dietary vitamin E on plasma, red blood cells (RBC), hepatic antioxidant status, and antioxidant enzyme activities was investigated. Three groups of six Sprague-Dawley rats were fed 0, 100, or 1,500 ppm vitamin E for eight weeks. Plasma alpha-tocopherol level was increased significantly by increasing dietary vitamin E (p < 0.05). Plasma lipid peroxidation (thiobarbituric acid-reactive substances) stimulation by 1 mM t-butyl hydroperoxide was correlated with dietary vitamin E level and was significantly greater in rats fed no vitamin E than in rats fed 100 or 1,500 ppm vitamin E (p < 0.05). RBC reduced glutathione (GSH) level was positively correlated with dietary vitamin E and was significantly greater in rats fed 1,500 ppm vitamin E than in rats fed 0 or 100 ppm vitamin E (p < 0.05). RBC oxidized glutathione was negatively correlated with dietary vitamin E. GSH redox status was expressed as the GSH-to-total GSH ratio; the ratio was also positively correlated with dietary vitamin E and was significantly greater in rats fed 1,500 ppm vitamin E than in rats fed no vitamin E (p < 0.05). For antioxidant enzymes, superoxide dismutase activity in hepatic cytosolic fraction was significantly greater in rats fed 1,500 ppm vitamin E than in rats fed 100 ppm vitamin E. Hepatic GSH reductase activity was significantly greater in rats fed 100 ppm vitamin E than in rats fed no vitamin E (p < 0.05). Dietary vitamin E had no effect on plasma vitamin C and protein thiol levels. In the systems studied, results indicated that dietary vitamin E selectively influences plasma vitamin E level, RBC GSH status, and hepatic cytosolic superoxide dismutase and GSH reductase activities.

Plasma lipoprotein cholesterol levels in rats fed a diet enriched in cholesterol and cholic acid

To investigate the effects of dietary cholesterol and cholic acid on plasma cholesterol levels, rats fed a cholesterol-free diet or a diet enriched in cholesterol (0.5% or 1%) with or without cholic acid supplementation were studied for 4 weeks. Although 0.5% cholesterol supplementation showed no effect on plasma total cholesterol and LDL-cholesterol levels in rats fed a diet without cholic acid treatment, the addition of dietary cholic acid caused an increase in plasma total cholesterol, LDL-cholesterol and VLDL-cholesterol levels in rats fed a cholesterol-rich diet. There was no significant change in HDL-cholesterol levels among the dietary groups. Rats fed a diet enriched in cholesterol have increased liver total lipids and total cholesterol contents. In addition, lower liver lipid peroxide concentration was found in rats fed a cholesterol-rich diet when compared with those fed the control diet. It is interesting that cholic acid supplementation led to an increase in hepatic cholesterol content and a decrease in liver lipid peroxide concentration in rats fed a cholesterol-rich diet. Results from this study suggest that dietary cholesterol and cholic acid might play an important role in regulation of lipid metabolism in rats.

[Lipids, lipoproteins and apolipoproteins in normal newborns]

BACKGROUND

In Chile, there is a high prevalence of cardiovascular diseases. Because atherosclerosis starts in childhood, it is important to assess serum lipid levels in children.

AIM

To measure serum lipid levels in normal Chilean newborns.

SUBJECTS AND METHODS

A sample of umbilical cord venous blood was obtained from 156 normal newborns (76 male) immediately after delivery. Total and HDL cholesterol, triglycerides, apoprotein A1, B and lipoprotein (a) were measured.

RESULTS

Mean values for total cholesterol in males, females and in the total sample were 60.6, 67.8 and 64 mg/dl respectively. The figures for HDL cholesterol were 24.9, 29.3 and 27 mg/dl, for LDL cholesterol were 28.3, 32.4 and 30 mg/dl, for triglycerides were 37.5, 30.3 and 35 mg/dl, for apoprotein A1 were 69, 79 and 74 mg/dl, for apoB were 23, 25 and 24 mg/dl and for lipoprotein (a) were 1.58, 1.79 and 1.69 mg/dl. Total cholesterol, HDL cholesterol, triglycerides and apoprotein A1 were significantly different between sexes. Percentiles 5 and 95 for total cholesterol were 37 and 111, for HDL cholesterol were 14 and 40, for LDL cholesterol were 13 and 57, for triglycerides were 20 and 69, for apoprotein A1 were 53 and 101, for apoprotein B were 11 and 48 and for lipoprotein (a) were 1.3 and 2.1 mg/dl. Five percent of children had apoprotein B values over 48 mg/dl.

CONCLUSIONS

The detection of high levels of apoprotein B in newborns, could allow the early identification of individuals with high cardiovascular risk.

Effect of dietary fish oil on plasma lipoprotein cholesterol in rats fed a diet enriched in cholesterol and sucrose

The aim of this study was to examine the effect of dietary fish oil on plasma lipoprotein cholesterol levels in rats fed different carbohydrate sources. Male Wistar rats fed a soy bean oil diet or a fish oil diet containing 0.5% cholesterol were studied for 7 weeks. Corn starch or sucrose were used as carbohydrate sources in the experimental diet. Fish oil supplementation significantly (p < 0.05) decreased plasma VLDL (very low density lipoprotein) cholesterol in rats fed a diet containing corn starch. However, there was no significant difference in plasma total cholesterol and LDL (low density lipoprotein) cholesterol in rats fed a corn starch diet with fish oil treatment. In the experiment with sucrose, significantly (p < 0.05) decreased plasma total cholesterol, LDL cholesterol and VLDL cholesterol were observed in rats fed a fish oil diet. Although higher plasma total and VLDL cholesterol levels were found in rats fed the sucrose diet when compared with those fed the corn starch diet, no significant difference between the corn starch group and the sucrose group was observed in rats after fish oil treatment. Results from the present study suggest that the carbohydrate source might play an important role in the regulation of plasma lipoprotein metabolism in rats fed fish oil.

[Serum lipid levels in children and teenagers from Concepción, Chile]

BACKGROUND

There is a relationship between serum lipid levels in children with those of adults. Preventive measures to reduce serum lipid levels should start in childhood.

AIM

To study serum lipid levels in a representative sample of children and teenagers from Concepción, Chile.

SUBJECTS AND METHODS

Serum total, HDL cholesterol and triglycerides were measured in 1,286 males and 816 females from 5 to 18 years old in the city of Concepción.

RESULTS

Mean total cholesterol levels were 159 +/- 30 and 162 +/- 31 mg/dl in males and females respectively. The figures for HDL cholesterol were 46 +/- 11 and 47 +/- 11 mg/dl, for LDL cholesterol were 94 +/- 27 and 96 +/- 29 mg/dl and for triglycerides were 80 +/- 35 and 87 +/- 38 mg/dl. Nine percent of males and 12% of females had a total cholesterol over 200 mg/dl. Likewise 10% of males and 11% of females had a LDL cholesterol over 130 mg/dl.

CONCLUSIONS

These numbers will help to plan and perform interventions in children, in order to prevent cardiovascular diseases.

[Lipoprotein in children and adolescents: relationship with family history of coronary artery disease]

BACKGROUND

Lipoprotein (a) is considered an independent cardiovascular risk factor.

AIM

To study lipoprotein (a) levels in children of 18 years old or less with or without family history of coronary artery disease.

SUBJECTS AND METHODS

Forty four children aged between 3 and 18 years old with a family history of coronary artery disease and 44 age and sex matched controls were studied. A fasting blood sample was obtained to measure total, HDL and LDL cholesterol, triglycerides, A1 and B apoproteins and lipoprotein (a).

RESULTS

Compared to controls, children with a family history of coronary disease had higher total cholesterol (177 +/- 35 and 159 +/- 23 mg/dl respectively), LDL cholesterol (112 +/- 34 and 94 +/- 21 mg/dl respectively), triglycerides (89 +/- 38 and 71 +/- 25 mg/dl respectively), apoprotein B (85 +/- 17 and 65 +/- 13 mg/dl respectively) and lipoprotein (a) (40 +/- 50 and 22 +/- 31 mg/dl respectively). Thirty two percent of children with positive family history had lipoprotein (a) levels over 30 mg/dl, compared to 23% of controls.

CONCLUSIONS

Children with family history of coronary artery disease have higher levels of cholesterol, triglycerides and lipoprotein (a) than matched controls.

Toxic effects of grass carp, snake and chicken bile juices in rats

To evaluate the toxic effects of different animal bile juices, male Long-Evans rats were used and treated orally with different doses (0.03-0.6 ml) of grass carp, snake and chicken bile juices. After treating with one high dose (0.6 ml) for 6 and 24 h, the levels of glutamic oxaloacetic transaminase (GOT), glutamic pyruvic transaminase (GPT), alkaline phosphatase (ALP), blood urea nitrogen (BUN) and creatinine in the plasma of rats in the grass carp bile juice group became higher than those of the other two bile treated groups. After 3-days periodic treatment with 0.3 ml of each animal bile juice for 28 days, the levels of GOT, GPT, BUN and creatinine in the plasma of rats were significantly increased, especially the grass carp bile juice-treated rats. It appeared that the rats administered with snake and chicken bile juices for a much longer time were poisoned and had the same symptoms as those treated with grass carp bile juice.

[Influence of ethnic and environmental factors the lipid profile in school children from the VIII Region]

We studied fasting total, HDL cholesterol and triglycerides in 329 children aged from 6 to 15 years. One hundred and ten lived in Concepción and were considered urban. Two hundred nineteen lived in Alto Bio-Bio and were considered rural; of these, 173 had a pehuenche aboriginal origin. Rural pehuenche, rural non pehuenche and urban children had a total cholesterol of 123.7 +/- 23, 133.7 +/- 25.8 and 153.7 +/- 29.7 mg/dl respectively, a HDL cholesterol of 39.2 +/- 9.1, 38.8 +/- 9.1 and 46.2 +/- 11.3 mg/dl respectively and triglycerides of 83.3 +/- 33.5, 96.7 +/- 33.5 and 81.9 +/- 33.3 mg/dl respectively. Lipid levels were above safe values in 2.9% of pehuenche, 8.7% non pehuenche rural and 13.6% or urban children. It is concluded that the higher lipid levels of urban and non pehuenche children supports the favorable effect of rural environment and pehuenche ethnic origin on cardiovascular risk factors.

Lipoprotein, lecithin:cholesterol acyl transferase and acetyl CoA carboxylase in stroke-prone spontaneously hypertensive rats fed a diet high in eicosapentaenoic acid

To investigate the effect of dietary eicosapentaenoic acid (EPA) on plasma lipoprotein levels, lecithin:cholesterol acyltransferase (LCAT) activity and liver acetyl CoA carboxylase activity, highly concentrated EPA (78%) purified from sardine oil was fed to stroke-prone spontaneously hypertensive rats (SHRSP) for 30 days. Significantly (P < 0.05) lower systolic blood pressure and plasma total cholesterol were observed in rats fed an EPA diet. In addition, higher HDL cholesterol and lower VLDL cholesterol levels were found in rats fed the EPA diet as compared with rats fed the control diet. However, no significant change of plasma LDL cholesterol was observed in rats between the two dietary groups. EPA supplementation increased the activity of plasma LCAT in rats. In addition, rats fed an EPA diet had lower liver total lipids and adipose tissue weights. However, higher liver acetyl CoA carboxylase activity was observed in rats fed the EPA diet. Results from the present study suggest that dietary EPA might stimulate the plasma lipoprotein metabolism and also alter lipogenesis in the liver of SHRSP rats.

Serum adenosine deaminase in the early diagnosis of typhoid fever

To study the usefulness of the enzyme adenosine deaminase for the early diagnosis of typhoid fever, its activity in serum was assayed in 277 children admitted to the Hospital Guillermo Grant Benavente at Concepción, Chile, from March, 1988, to December, 1990. The children were distributed into seven groups: control, N = 82; bacteremia, N = 8; acute viral respiratory infection, N = 43; febrile children with miscellaneous etiologies, N = 49; pulmonary tuberculosis, N = 3; hepatitis A virus infection, N = 30; and typhoid fever, N = 62. The medium serum adenosine deaminase values were significantly higher in children with typhoid fever (P < 0.0001) in relation to the values in the control group (122.2 +/- 40.7 vs 28.1 +/- 8.4 units/liter at 37 degrees C). This test had a sensitivity of 91.9% and a specificity of 92.5% in identifying the patient with typhoid fever when using 80 units/liter as the cutoff values. The positive predictive value of the test was 83.8% and the negative predictive value was 96%. Determination of adenosine deaminase values in serum could be helpful in the early diagnosis of typhoid fever.

Effect of trans fatty acids on plasma lipids, platelet function and systolic blood pressure in stroke-prone spontaneously hypertensive rats

To investigate the effect of trans fatty acids on plasma lipid levels and systolic blood pressure, hydrogenated corn oil was fed to SHRSP (stroke-prone spontaneously hypertensive rats) and WKY (Wistar-Kyoto) rats for 30 days. Significantly lower systolic blood pressure and plasma total cholesterol were observed in SHRSP rats fed trans fatty acids when compared with rats fed cis fatty acids from olive oil. In addition, higher HDL cholesterol and lower VLDL plus chylomicron cholesterol levels were found in SHRSP rats fed trans fatty acids. Although no significant changes of systolic blood pressure and plasma total cholesterol levels were observed in WKY rats after trans fatty acids treatment, WKY rats fed trans fatty acids had lower plasma LDL cholesterol and higher HDL cholesterol levels. In addition, platelet aggregation induced by collagen was decreased in WKY rats fed trans fatty acids. It is interesting that trans fatty acids increased the activity of plasma lecithin:cholesterol acyltransferase (LCAT) in both SHRSP and WKY rats. The observed influence of trans fatty acids on plasma lipid levels, systolic blood pressure and platelet aggregation suggests that trans fatty acids might prevent thrombotic disorders in SHRSP rats.

Effect of dietary protein on the peroxidation of eicosapentaenoic acid in stroke-prone spontaneously hypertensive rats

In order to investigate the effect of dietary EPA on liver GSH peroxidase (GSH-Px) activity in rats, highly concentrated EPA (78% ethyl ester form) was administrated to SHRSP (Stroke-prone spontaneously hypertensive rat) that were fed a casein, SPI (soybean protein isolate) or SPI diet with methionine for 4 weeks. The content of liver GSH in rats fed SPI was lower than that of rats fed the casein diet. Although no significant difference of liver GSH-Px was observed in rats after EPA supplement, a decrease of liver GSH-Px activity was found in rats fed the SPI diet when compared with rats fed the casein diet. The changes of liver GSH content and GSH-Px activity in rats fed SPI were found to be associated with methionine supplement. Addition of methionine to the SPI diet resulted in an increase of liver GSH content and GSH-Px activity. In addition, liver lipid peroxide concentration was increased in rats fed the SPI diet after EPA treatment. In contrast, EPA administered rats fed the SPI diet containing methionine showed a lower liver lipid peroxide concentration. These results suggest that methionine may play an important role in regulation of the utilization of EPA in SHRSP when fed a SPI diet.