Involvement of the vagus nerve and hepatic gene expression in serum adiponectin concentrations in mice

Several humoral factors, such as adiponectin and urate, have been suggested to affect metabolic syndromes. Previously, we reported a reduction in blood adiponectin concentrations after a high-fructose diet partially via the vagus nerve in rats. Although a lithogenic diet (LD), i.e., supplementation of a normal control diet (CT) with 0.6% cholesterol and 0.2% sodium cholate, reduced blood adiponectin concentrations, the involvement of the vagus nerve in this mechanism remains unclear. To estimate the involvement of the vagus nerve in the regulation of blood adiponectin concentrations using an LD, male imprinting control region mice that had been vagotomized (HVx) or only laparotomized (Sham) were administered a CT or an LD for 10 weeks. Serum adiponectin concentrations in the Sham-LD, HVx-CT, and HVx-LD groups were reduced by half compared with the Sham-CT group. The hepatic mRNA levels of fibroblast growth factor 21 (Fgf21), which reportedly stimulates adiponectin secretion from white adipose tissue, were lower in the LD groups compared with the CT groups. HepG2 hepatoma cells showed that various bile acids reduced the mRNA expression of FGF21. Moreover, the LD increased serum urate concentrations and reduced hepatic expressions of the acyl-CoA oxidase 1 (Acox1) mRNA and glucokinase, suggesting insufficient regeneration of ATP from AMP. In conclusion, serum adiponectin concentration may be regulated via the vagus nerve in normal mice, whereas a reduction of hepatic Fgf21 mRNA by bile acids may also lower serum adiponectin levels. Moreover, the LD may promote hepatic AMP accumulation and subsequently increase the serum urate concentration in mice. (AU)

Involvement of the vagus nerve and hepatic gene expression in serum adiponectin concentrations in mice.

Several humoral factors, such as adiponectin and urate, have been suggested to affect metabolic syndromes. Previously, we reported a reduction in blood adiponectin concentrations after a high-fructose diet partially via the vagus nerve in rats. Although a lithogenic diet (LD), i.e., supplementation of a normal control diet (CT) with 0.6% cholesterol and 0.2% sodium cholate, reduced blood adiponectin concentrations, the involvement of the vagus nerve in this mechanism remains unclear. To estimate the involvement of the vagus nerve in the regulation of blood adiponectin concentrations using an LD, male imprinting control region mice that had been vagotomized (HVx) or only laparotomized (Sham) were administered a CT or an LD for 10 weeks. Serum adiponectin concentrations in the Sham-LD, HVx-CT, and HVx-LD groups were reduced by half compared with the Sham-CT group. The hepatic mRNA levels of fibroblast growth factor 21 (Fgf21), which reportedly stimulates adiponectin secretion from white adipose tissue, were lower in the LD groups compared with the CT groups. HepG2 hepatoma cells showed that various bile acids reduced the mRNA expression of FGF21. Moreover, the LD increased serum urate concentrations and reduced hepatic expressions of the acyl-CoA oxidase 1 (Acox1) mRNA and glucokinase, suggesting insufficient regeneration of ATP from AMP. In conclusion, serum adiponectin concentration may be regulated via the vagus nerve in normal mice, whereas a reduction of hepatic Fgf21 mRNA by bile acids may also lower serum adiponectin levels. Moreover, the LD may promote hepatic AMP accumulation and subsequently increase the serum urate concentration in mice.

In vitro fermentation potential of the residue of Korean red ginseng root in a mixed culture of swine faecal bacteria.

Agricultural by-products such as the ginseng residue contain dietary fibre. This study was aimed at investigating the intestinal fermentation potential of the residue of Korean red ginseng root using an in vitro simulator of the colon using swine fecal bacteria. pH-Controlled glass fermentors were used to conduct a small scale in vitro batch fermentation under anaerobic conditions for 48 h. One of the following substrates was included in each fermentor: commercial cellulose (CEL), xylooligosaccharide (XOS), and crude ginseng-insoluble fibre (CGF). The pH was lower (p < 0.05) and the production of total short chain fatty acid was increased (p < 0.05) in the XOS and CGF groups compared with the CEL group after 6 h of incubation. The α-diversity analysis of the microbial community at 48 h showed that the number of bacterial species was (p < 0.05) reduced in the XOS and CGF groups compared with that in the CEL group. ß-Diversity of the microbial population at 48 h showed that all groups were clustered differently. The relative abundance of Bifidobacterium and Prevotella in the CGF group were significantly (p < 0.05) higher than those in the CEL and XOS groups. Ammonia nitrogen production in the XOS and CGF groups was (p < 0.05) lower after 6 h of incubation, and skatole production in the CGF group was (p < 0.05) lower at 48 h than that in the CEL group. These results suggested that the ginseng residue might be fermentable in the large intestine and thus would promote the maintenance of a healthy colonic environment in the host.

Dietary adzuki bean paste dose-dependently reduces visceral fat accumulation in rats fed a normal diet.

The aim of this study was to evaluate the dose-dependent effect of adzuki bean (Vigna angularis) paste (ABP) on visceral fat accumulation in rats. ABP is a rich source of indigestible carbohydrates (18.5%) with fiber and resistant starch (RS) contents of 14.5% and 4.0%, respectively. Animals were fed one of the following diets, control (CON), 30% ABP or 58.9% ABP for 28 days. The daily dietary energy intake was lowered (p < 0.05) and reduced visceral fat accumulation and lower serum lipid levels were observed in ABP fed groups. ABP consumption dose-dependently increased (p < 0.05) the daily fecal lipid and fecal acidic sterol excretions. On the other hand, cecal content and fecal moisture content in the 58.9% ABP group were greater (p < 0.05) than the CON group, while there was no significant difference between the two ABP fed groups. Both 30% and 58.9% ABP diets had significantly (p < 0.05) higher contents of cecal acetic, propionic and n-butyric acids, and lowered cecal pH, independently of the ABP dose. Microbial community data of rats fed ABP diets exhibited higher alpha-diversities than the rats fed CON diet, based on the Shannon Index and the number of observed species index, where the two ABP groups exhibited a similar alpha diversity. The weighted UniFrac-based principal coordinate analysis plot of cecal microbial community data showed that the ABP had a substantial effect on the cecal microbial composition. Furthermore, cecal bacterial 16S rRNA gene sequencing revealed that the ABP supplemented diets decreased the ratio of Firmicutes to Bacteroidetes. These findings suggested that the cecal fermentation of fiber and RS in ABP, might have decreased the energy intake, altered the gut microbiota composition, increased fecal lipid output, and thereby reduced fat accumulation in rats.

Effects of Raw Potato Starch with High Resistant Starch Levels on Cecal Fermentation Properties in Rats.

The effects of potato starch, isolated from Snowden (SD) and Kitahime (KH) varieties, on cecal fermatation properties in rats were evaluated. In high-amylose cornstarch (HAS), SD and KH groups, cecal acetate and total short-chain fatty acid concentrations were increased and cecal pH was lowered compared to control (CON) group. Further, cecal immunoglobulin A levels were increased and cecal ammonia-nitrogen, p-cresol, skatole and indole concentrations were lowered in HAS, SD and KH groups compared to the CON group. Therefore, potato starch might possess beneficial intestinal fermentation properties.

Safety and efficacy of adzuki bean extract in subjects with moderate to high LDL-C: a randomized trial.

The safety and efficacy of polyphenol-containing adzuki bean extract on lipid metabolism were evaluated in human subjects in an 8-week, randomized, double-blind, placebo-controlled, parallel intervention study. No adverse effects were observed in the participants receiving adzuki bean extract. The adzuki bean group showed a significant increase in the ΔHDL-C concentration compared with the placebo group after 4 weeks of intervention (3.76 ± 7.79 mg/dL vs. -0.08 ± 6.03 mg/dL), respectively, and both groups showed reduced ∆HDL-C concentrations, with the adzuki bean extract group showing a return to the baseline levels (0.36 ± 5.36 mg/dL) and the placebo group showing a decrease to below the baseline levels (-3.17 ± 7.79 mg/dL) at week 8. This short-term study represents the first step in establishing the practicality, safety, and plausibility of HDL-C maintaining effects of adzuki bean extract in human subjects.

Effect of a combination of inulin and polyphenol-containing adzuki bean extract on intestinal fermentation in vitro and in vivo.

The effect of a combination of inulin (INU) and polyphenol-containing adzuki bean extract (AE) on intestinal fermentation was examined in vitro using fermenters for 48 h and in vivo using rats for 28 d. The total short-chain fatty acid concentrations in the fermenters were decreased by a combination of INU and AE, but the concentration in the INU + AE group was higher than the cellulose (CEL) and CEL + AE groups. The cecal propionate concentration was increased by a combination of INU and AE compared with their single supplement. The ammonia-nitrogen concentration in the fermenters and rat cecum was decreased by INU and AE. Cecal mucin levels were increased by INU and AE respectively. Therefore, our observations suggested that the combination of INU and AE might be a material of functional food that includes several healthy effects through intestinal fermentation.