Effects of Thermally-Oxidized Frying Oils (Corn Oil and Lard) on Gut Microbiota in Hamsters.

Repeated reuse of frying oil raises health concerns due to the accumulation of oxidative products after each frying cycle. Gut microbiota is integral in lipid metabolism and immune regulation. The present study was designed to investigate the effects of thermally-oxidized corn oil and lard on gut microbiota in relation to atherosclerosis, inflammatory cytokines, and plasma lipids. Male Golden Syrian hamsters were randomly divided into four groups and fed one of four diets containing fresh corn oil (CF), oxidized corn oil (CO), fresh lard (LF), and oxidized lard (LO), for six weeks. CO and LO were prepared by deep-frying potatoes in corn oil or lard for seven days. Results indicated that oxidized oil and lard caused the loss of species diversity and richness of gut microbiota. Feeding CO and LO also reduced the body and adipose tissue weights, associated with genus Acetatifactor and Allobaculum. Plasma triacylglycerols significantly increased by 51% in the CO and 35% in the LO group compared with that in their CF and LF counterparts, respectively. CO could also affect the abundance of specific bacteria genera: Bacteroides, Barnesiella, Acetatifactor, Allobaculum, Clostridium_IV, Clostridium_XIVa, Coprococcus, Lactococcus, Paraprevotella, Parasutterella, and Oscillibacter. In addition, CO and LO could adversely remodel gut composition and affect intestinal production of short-chain fatty acids, pro-inflammatory biomarkers (LPS and IL-6), anti-inflammatory biomarker IL-10, and atherosclerotic progression. It was concluded that frying oil could adversely modulate the gut microbiota and exacerbate the atherosclerosis at least in a hypercholesterolemia hamster model.

Effects of hawthorn seed oil on plasma cholesterol and gut microbiota.

BACKGROUND: Hypercholesterolemia and gut microbiota dysbiosis are associated with the risk of cardiovascular diseases. Hawthorn fruits has shown to be cardioprotective and hypocholesterolemic. However, no studies to date have studied the biological activity of hawthorn seed oil (HSO). The present study was to investigate if HSO could favourably reduce plasma cholesterol and modulate gut microbiota in hypercholesterolemia hamsters. METHODS: Golden Syrian hamsters (age, 8 weeks) were randomly divided into five groups (n = 8, each) and fed one of the following five diets, namely a non-cholesterol diet, a high cholesterol diet containing 0.15% cholesterol (HCD); a HCD diet with addition of 4.75% HSO (LHSO), a HCD diet with addition of 9.5% HSO (HHSO), a HCD diet with addition of 0.50% cholestyramine as positive control diet. After 6-week dietary intervention, plasma lipids, inflammatory markers, atherosclerosis plaque, hepatic and fecal lipids were quantified. Microbiota in fresh feces were analysed by sequencing 16S rRNA genes, while RT-PCR and Western blot analyses were employed to quantify the expression of genes involved in cholesterol homeostasis. RESULTS: HSO at a dose of 9.5% HSO could decrease plasma cholesterol and non-HDL-cholesterol by 15%. Additionally, both HSO experimental groups also suppressed mRNA of 3-Hydroxy-3-Methylglutaryl-CoA Reductase (HMG-CoA-R). Supplementation of HSO at 4.75% could significantly increase the excretion of fecal acidic sterols, accompanied by elevation of short-chain fatty acid levels in feces. The analyses of gut microbiome indicated that HSO supplementation could selectively alter the genera abundance of gut bacteria that were correlated with cholesterol metabolism including unclassified_f__Christensenellaceae, Ruminococcaceae_NK4A214_ group, norank_o_Gastranaerophilales, Faecalibaculum, Peptococcus, norank_f__Clostridiales_vadinBB60_group and Ruminococcus_2. CONCLUSIONS: HSO supplementation was able to decrease plasma cholesterol by favourably modulating gut microbiota composition and gut-derived metabolites associated with cholesterol regulation.

Peony seed oil decreases plasma cholesterol and favorably modulates gut microbiota in hypercholesterolemic hamsters.

PURPOSE: Peony (Paeonia spp.) seed oil (PSO) contains a high amount of α-linolenic acid. The effects of PSO on hypercholesterolemia and gut microbiota remains unclear. The present study was to investigate effects of PSO supplementation on cholesterol metabolism and modulation of the gut microbiota. METHODS: Male Golden Syrian hamsters (n = 40) were randomly divided into five groups (n = 8, each) fed one of the following diets namely low-cholesterol diet (LCD); high cholesterol diet (HCD); HCD with PSO substituting 50% lard (LPSO), PSO substituting 100% lard (HPSO) and HCD with addition of 0.5% cholestyramine (PCD), respectively, for 6 weeks. RESULTS: PSO supplementation dose-dependently reduced plasma total cholesterol (TC) by 9-14%, non-high-density lipoprotein cholesterol (non-HDL-C) by 7-18% and triacylglycerols (TG) by 14-34% (p < 0.05). In addition, feeding PSO diets reduced the formation of plaque lesions by 49-61% and hepatic lipids by 9-19% compared with feeding HCD diet (p < 0.01). PSO also altered relative genus abundance of unclassified_f__Coriobacteriaceae, unclassified_f__Erysipelotrichaceae, Peptococcus, unclassified_f__Ruminococcaceae, norank_o__Mollicutes_RF9 and Christensenellaceae_R-7_group. CONCLUSIONS: It was concluded that PSO was effective in reducing plasma cholesterol and hepatic lipids and favorably modulating gut microbiota associated with cholesterol metabolism.

Rutin and Quercetin Decrease Cholesterol in HepG2 Cells but Not Plasma Cholesterol in Hamsters by Oral Administration.

Rutin (R) and quercetin (Q) are two widespread dietary flavonoids. Previous studies regarding the plasma cholesterol-lowering activity of R and Q generated inconsistent results. The present study was therefore carried out to investigate the effects of R and Q on cholesterol metabolism in both HepG2 cells and hypercholesterolemia hamsters. Results from HepG2 cell experiments demonstrate that both R and Q decreased cholesterol at doses of 5 and 10 µM. R and Q up-regulated both the mRNA and protein expression of sterol regulatory element binding protein 2 (SREBP2), low-density lipoprotein receptor (LDLR), and liver X receptor alpha (LXRα). The immunofluorescence study revealed that R and Q increased the LDLR expression, while only Q improved LDL-C uptake in HepG2 cells. Results from hypercholesterolemia hamsters fed diets containing R (5.5 g/kg diet) and Q (2.5 g/kg diet) for 8 weeks demonstrate that both R and Q had no effect on plasma total cholesterol. In the liver, only Q reduced cholesterol significantly. The discrepancy between the in vitro and in vivo studies was probably due to a poor bioavailability of flavonoids in the intestine. It was therefore concluded that R and Q were effective in reducing cholesterol in HepG2 cells in vitro, whereas in vivo, the oral administration of the two flavonoids had little effect on plasma cholesterol in hamsters.

Blueberry and cranberry anthocyanin extracts reduce bodyweight and modulate gut microbiota in C57BL/6 J mice fed with a high-fat diet.

PURPOSE: Blueberry and cranberry are rich in anthocyanins. The present study was to investigate the effects of anthocyanin extracts from blueberry and cranberry on body weight and gut microbiota. METHODS: C57BL/6 J Mice were divided into six groups (n = 9 each) fed one of six diets namely low-fat diet (LFD), high-fat diet (HFD), HFD with the addition of 1% blueberry extract (BL), 2% blueberry extract (BH), 1% cranberry extract (CL), and 2% cranberry extract (CH), respectively. RESULTS: Feeding BL and BH diets significantly decreased body weight gain by 20-23%, total adipose tissue weight by 18-20%, and total liver lipids by 16-18% compared with feeding HFD. Feeding CH diet but not CL diet reduced the body weight by 27%, accompanied by a significant reduction of total plasma cholesterol by 25% and tumor necrosis factor alpha (TNF-α) by 38%. The metagenomic analysis showed that the supplementation of blueberry and cranberry anthocyanin extracts reduced plasma lipopolysaccharide concentration, accompanied by a reduction in the relative abundance of Rikenella and Rikenellaceae. Dietary supplementation of berry anthocyanin extracts promoted the growth of Lachnoclostridium, Roseburia, and Clostridium_innocuum_group in genus level, leading to a greater production of fecal short-chain fatty acids (SCFA). CONCLUSIONS: It was concluded that both berry anthocyanins could manage the body weight and favorably modulate the gut microbiota at least in mice.

Wild Melon Seed Oil Reduces Plasma Cholesterol and Modulates Gut Microbiota in Hypercholesterolemic Hamsters.

Wild melon (Cucumis melo var. agrestis) seed oil (CO) contains 71.3% polyunsaturated fatty acids. The present study investigated the effects of CO on blood cholesterol and gut microbiota. Hamsters (n = 32) were randomly divided into four groups and given one of four diets, namely noncholesterol diet (NCD), high-cholesterol diet containing 0.1% cholesterol (HCD), HCD containing 4.75% CO (COL), and HCD containing 9.5% CO (COH) for 6 weeks. CO supplementation at 9.5% in the diet reduced plasma cholesterol by 24% and enhanced the excretion of fecal bile acids by 150%. CO supplementation upregulated the gene expression of hepatic cholesterol 7α-hydroxylase (CYP7A1). In addition, supplementation of CO in the diet remarkably increased the production of fecal short-chain fatty acids and favorably altered the relative abundances of Eubacteriaceae, Clostridiales_vadinBB60_group, Ruminococcaceae, Streptococcaceae, and Desulfovibrionaceae at a family level. It was concluded that CO could reduce plasma cholesterol via promoting the excretion of fecal acidic sterols and modulating gut microbiota.

Fish Oil Is More Potent than Flaxseed Oil in Modulating Gut Microbiota and Reducing Trimethylamine-N-oxide-Exacerbated Atherogenesis.

Trimethylamine-N-oxide (TMAO) is a risk factor for atherosclerosis. We compared the potency of fish oil with flaxseed oil in reducing TMAO-exacerbated atherogenesis. Five groups of ApoE-/- mice were given one of five diets, namely, a low-fat diet, a Western high fat diet (WD), a WD plus 0.2% TMAO, and two WDs containing 0.2% TMAO with 50% lard being replaced by flaxseed oil or fish oil. TMAO accelerated atherosclerosis and disturbed cholesterol homeostasis. Compared with flaxseed oil, fish oil was more effective in inhibiting TMAO-induced atherogenesis by lowering plasma cholesterol and inflammatory cytokines. Both oils could reverse TMAO-induced decrease in fecal acidic sterols. Fish oil promoted fecal output of neutral sterols and downregulated hepatic cholesterol biosynthesis. Fish oil was more effective than flaxseed oil in promoting the growth of short-chain fatty acid-producing bacteria and lowering microbial generation of lipopolysaccharide. In conclusion, fish oil is more potent than flaxseed oil to ameliorate TMAO-exacerbated atherogenesis.

Sea buckthorn seed oil reduces blood cholesterol and modulates gut microbiota.

Sea buckthorn seed oil (SBSO) has been used as a functional food in the prevention of heart diseases. The present study investigates the effects of SBSO on blood cholesterol and the gut microbiota in hypercholesterolemia hamsters. Four groups of hamsters (n = 8 each) were given one of four diets, namely a non-cholesterol control diet (NCD), a high-cholesterol control diet (HCD) containing 0.1% cholesterol, and an HCD diet with sea buckthorn seed oil replacing 50% lard (SL) or replacing 100% lard (SH). Feeding SL and SH diets could reduce blood total cholesterol by 20-22%. This was accompanied by the down-regulation of the gene expression of acyl-CoA:cholesterol acyltransferase 2 (ACAT2), microsomal triacylglycerol transport protein (MTP), and ATP-binding cassette transporter8 (ABCG8). SBSO supplementation also increased the production of intestinal short-chain fatty acids and fecal outputs of neutral sterols. Metagenomic analysis demonstrated that feeding SL and SH diets could favorably modulate the relative abundance of Bacteroidales_S24-7_group, Ruminococcaceae, and Eubacteriaceae. It was therefore concluded that SBSO was effective in reducing blood cholesterol in hypercholesterolemic hamsters via increasing intestinal cholesterol excretion and promoting the growth of SCFA-producing bacteria.

Soybean germ oil reduces blood cholesterol by inhibiting cholesterol absorption and enhancing bile acid excretion.

Health benefits of soybean germ oil have not yet been fully explored. The present study examined the blood cholesterol-lowering activity of soybean germ oil and the underlying mechanisms in hypercholesterolemic hamsters. Forty hamsters were randomly assigned into five groups and fed a non-cholesterol diet, a high cholesterol diet and one of three high cholesterol diets containing 0.50% cholestyramine, 4.75% soybean germ oil, and 9.50% soybean germ oil, respectively, for 6 weeks. The result showed that soybean germ oil significantly decreased plasma cholesterol by 18.5-31.5%, which was accompanied by 28.3-62.7% increase in excretion of fecal neutral sterols and bile acids. The effect was mediated by down-regulation of intestinal Niemann-Pick C1-like 1 protein (NPC1L1) and up-regulation of liver cholesterol-7α-hydroxylase (CYP7A1). We concluded that soybean germ oil favorably modulated the blood cholesterol concentration by inhibiting cholesterol absorption through inhibiting gene expression of NPC1L1 and by enhancing bile acid excretion via promoting gene expression of CYP7A1.