Pectin and high-amylose maize starch increase caecal hydrogen production and relieve hepatic ischaemia-reperfusion injury in rats.

We investigated whether the feeding of high H2-generating dietary fibre and resistant starch (RS) could suppress hepatic ischaemia-reperfusion (IR) injury, which results from oxidative stress, in rats fed a pectin (Pec) or high-amylose maize starch (HAS) diet. Male Sprague-Dawley rats were fed a control (C) diet, with or without Pec (0-5 % Pec) or HAS (0-30 % HAS) supplementation for 7 d. Portal H2 concentration showed a significant dose-dependent increase with the amount of Pec or HAS supplementation. Plasma alanine and aspartate aminotransferase activities remarkably increased in the C rats (5 % cellulose) due to IR treatment, while it decreased significantly or showed tendencies to decrease in 5 % Pec and 20 % HAS diet-fed rats. The hepatic oxidised glutathione (GSSG):total glutathione ratio increased significantly in IR rats maintained on the C diet compared with sham-operated rats. On the other hand, reduced glutathione (GSH):total glutathione and GSH:GSSG ratios decreased significantly. The GSSG:total glutathione ratio that increased due to IR treatment decreased significantly on HAS and Pec intake, while GSH:total glutathione and GSH:GSSG ratios increased significantly. Hepatic sinusoids of IR rats fed the C diet were occluded, but those of IR rats fed the Pec diet were similar to those in the sham-operated rats. In conclusion, we found that Pec or HAS, which enhance H2 generation in the large intestine, alleviated hepatic IR injury. The present study demonstrates another physiological significance of dietary fibre and RS.We investigated whether the feeding of high H2-generating dietary fibre and resistant starch (RS) could suppress hepatic ischaemia-reperfusion (IR) injury, which results from oxidative stress, in rats fed a pectin (Pec) or high-amylose maize starch (HAS) diet. Male Sprague-Dawley rats were fed a control (C) diet, with or without Pec (0-5 % Pec) or HAS (0-30 % HAS) supplementation for 7 d. Portal H2 concentration showed a significant dose-dependent increase with the amount of Pec or HAS supplementation. Plasma alanine and aspartate aminotransferase activities remarkably increased in the C rats (5 % cellulose) due to IR treatment, while it decreased significantly or showed tendencies to decrease in 5 % Pec and 20 % HAS diet-fed rats. The hepatic oxidised glutathione (GSSG):total glutathione ratio increased significantly in IR rats maintained on the C diet compared with sham-operated rats. On the other hand, reduced glutathione (GSH):total glutathione and GSH:GSSG ratios decreased significantly. The GSSG:total glutathione ratio that increased due to IR treatment decreased significantly on HAS and Pec intake, while GSH:total glutathione and GSH:GSSG ratios increased significantly. Hepatic sinusoids of IR rats fed the C diet were occluded, but those of IR rats fed the Pec diet were similar to those in the sham-operated rats. In conclusion, we found that Pec or HAS, which enhance H2 generation in the large intestine, alleviated hepatic IR injury. The present study demonstrates another physiological significance of dietary fibre and RS

Human shoulder development is adapted to obstetrical constraints

ヒトは小さく生まれて大きく育つ --その秘密は鎖骨にあり--. 京都大学プレスリリース. 2022-04-13.In humans, obstetrical difficulties arise from the large head and broad shoulders of the neonate relative to the maternal birth canal. Various characteristics of human cranial development, such as the relatively small head of neonates compared with adults and the delayed fusion of the metopic suture, have been suggested to reflect developmental adaptations to obstetrical constraints. On the other hand, it remains unknown whether the shoulders of humans also exhibit developmental features reflecting obstetrical adaptation. Here we address this question by tracking the development of shoulder width from fetal to adult stages in humans, chimpanzees, and Japanese macaques. Compared with nonhuman primates, shoulder development in humans follows a different trajectory, exhibiting reduced growth relative to trunk length before birth and enhanced growth after birth. This indicates that the perinatal developmental characteristics of the shoulders likely evolved to ease obstetrical difficulties such as shoulder dystocia in humans

リン酸架橋でん粉のラットにおける脂質代謝改善作用

We investigated the effect of raw distarch potato starch (DPS) on lipid metabolism in rats. Rats were fed a 60% sucrose diet (control) and or one of 3 test diets containing 100 g/kg of DPS, native potato starch (NPS) or alkali-treated starch (ATS). DPS, NPS, and ATS contain 837 ppm, 818 ppm, and 818 ppm of phosphorous, respectively. There were no differences in final body weight among the rats fed the control, NPS, ATS, and DPS diets for 4 weeks. Rats fed the DPS diet had significantly smaller epididymal and perirenal fat pads than did the control rats (P<0.05). We also found that rats fed the DPS and NPS diets had significantly lower plasma triglyceride levels than did the control rats. Lower hepatic triglyceride concentrations were also seen in the DPS-and ATS-fed rats (-47 and -50%, respectively)compared to the controls. From these results, DPS, NPS and ATS can be seen to affect lipid metabolism in rats, with the greatest effect seen in the DPS group. The digestion of distarch phosphate of potato origin in the small intestine is suggested to have a large effect on the above mechanism

食物繊維およびタウリンの血中コレステロール低下機構に関する研究

高コレステロール血症を引き金とする動脈硬化症や心臓疾患が増加し，食品成分によるコレステロール代謝の正常化が重要視されている。著者は食物繊維およびタウリンによる血漿コレステロール濃度の低下機構を，それらの消化管内における作用に着目して調べた。その結果，発酵性の高い甜菜食物繊維（BF）で血漿コレステロール濃度低下作用が強く誘導されることを見出した。また，BFの作用発現に大腸の存在が必須で，大腸発酵が関与していることを明らかにした。有効な発酵産物の特定には至っていないが，発酵亢進だけでなく，糞中胆汁酸排泄の増加が同時に誘導されることが作用発現に重要であることを示唆した。タウリンの血漿コレステロール濃度低下作用には糞中胆汁酸排泄の増加が強く寄与していることを明確にした。この糞中胆汁酸排泄の増加がコレステロール7α-水酸化酵素の発現亢進ではなく，おもに回腸末端からの胆汁酸の吸収抑制に起因することを強く示唆した。以上より，血漿コレステロール濃度の低下が，食物繊維では消化管下部における発酵性に，タウリンでは回腸末端以降における胆汁酸吸収の抑制に起因することを示した。In view of the increasing incidence of arteriosclerosis and coronary heart disease caused by hypercholesterolemia, some food components are receiving attention because of their ability to normalize cholesterol metabolism. In this study we examined the mechanisms by which dietary fiber and taurine reduce the plasma cholesterol concentration by focusing on their effects in the digestive tract. We found that sugar beet fiber (BF), which is a high-fermentative dietary fiber, lowered plasma cholesterol concentrations in rats, and that passage through the lower digestive tract, especially the cecum, was necessary for initiating this effect. Moreover, the effect was related to fermentation of BF in the large intestine. The by-products of fermentation that induce this effect have not yet been determined. However, in addition to fermentation of BF in the large intestine, increased bile acid excretion into feces is critical for induction of the plasma cholesterol-lowering effect. We also confirmed that bile acid excretion into feces enhanced by taurine feeding plays a role in the plasma cholesterol-lowering effect. The inhibition of bile acid absorption, but not the induction of cholesterol 7α-hydroxylase, seems to be related mainly to an increase of bile acid excretion induced by taurine. Our findings indicate that the reduction of plasma cholesterol concentrations results from fermentability of dietary fiber in the lower digestive tract and inhibition of bile acid absorption from the distal ileum and lower digestive tract by taurine

Raw Chinese yam (Dioscorea opposita) promotes cecal fermentation and reduces plasma non-HDL cholesterol concentration in rats

We examined the effects of raw Chinese yam (Dioscorea opposita), containing resistant starch (RS), on lipid metabolism and cecal fermentation in rats. Raw yam (RY) and boiled yam (BY) contained 33.9% and 6.9% RS, respectively. Male Sprague-Dawley rats were fed a cholesterol-free, control (C) diet supplemented with or without 15 and 30 g of RY or BY/100 g for 3 wk. Plasma total cholesterol concentrations in the tail vein of rats fed the 30% RY diet were significantly lower than in the C group throughout the feeding period. Compared with the C group, non-HDL concentrations in arterial plasma in the 30% RY group was significantly reduced. Liver cholesterol concentration in rats fed the 30% RY diet was significantly higher compared with those fed the C diet. Hepatic cholesterol 7α-hydroxylase mRNA and fecal bile acid excretion were significantly higher in the BY, but not the RY group, compared with the C group. Fecal cholesterol excretion in the 30% RY group was greater compared with the C group. Hepatic microsomal triacylglycerol transfer protein mRNA was significantly lower in the 30% RY group compared with the C group. Cecal pools of acetate, propionate and butyrate were 113-257%, 181-476% and 410-789% greater in the RY group compared with the C group. These results suggest raw yam is effective as a source of RS and facilitates production of short chain fatty acid (SCFA), especially butyrate, in the rat cecum. In addition, RY has a plasma-cholesterol lowering effect, possibly due to the inhibited release of VLDL