Kohjiro Hashizume

Dietary milk fat globule membrane improves endurance capacity in mice

Milk fat globule membrane (MFGM) comprises carbohydrates, membrane-specific proteins, glycoproteins, phospholipids, and sphingolipids. We evaluated the effects of MFGM consumption over a 12-wk period on endurance capacity and energy metabolism in BALB/c mice. Long-term MFGM intake combined with regular exercise improved endurance capacity, as evidenced by swimming time until fatigue, in a dose-dependent manner. The effect of dietary MFGM plus exercise was accompanied by higher oxygen consumption and lower respiratory quotient, as determined by indirect calorimetry. MFGM intake combined with exercise increased plasma levels of free fatty acids after swimming. After chronic intake of MFGM combined with exercise, the triglyceride content in the gastrocnemius muscle increased significantly. Mice given MFGM combined with exercise had higher mRNA levels of peroxisome proliferator-activated receptor-γ coactivator 1α (Pgc1α) and CPT-1b in the soleus muscle at rest, suggesting that increased lipid metabolism in skeletal muscle contributes, in part, to improved endurance capacity. MFGM treatment with cyclic equibiaxial stretch consisting of 10% elongation at 0.5 Hz with 1 h on and 5 h off increased the Pgc1α mRNA expression of differentiating C2C12 myoblasts in a dose-dependent manner. Supplementation with sphingomyelin increased endurance capacity in mice and Pgc1α mRNA expression in the soleus muscle in vivo and in differentiating myoblasts in vitro. These results indicate that dietary MFGM combined with exercise improves endurance performance via increased lipid metabolism and that sphingomyelin may be one of the components responsible for the beneficial effects of dietary MFGM.

Triterpene alcohols and sterols from rice bran lower postprandial glucose-dependent insulinotropic polypeptide release and prevent diet-induced obesity in mice

Obesity is now a worldwide health problem. Glucose-dependent insulinotropic polypeptide (GIP) is a gut hormone that is secreted following the ingestion of food and modulates energy metabolism. Previous studies reported that lowering diet-induced GIP secretion improved energy homeostasis in animals and humans, and attenuated diet-induced obesity in mice. Therefore, food-derived GIP regulators may be used in the development of foods that prevent obesity. Rice bran oil and its components are known to have beneficial effects on health. Therefore, the aim of the present study was to clarify the effects of the oil-soluble components of rice bran on postprandial GIP secretion and obesity in mice. Triterpene alcohols [cycloartenol (CA) and 24-methylene cycloartanol (24Me)], β-sitosterol, and campesterol decreased the diet-induced secretion of GIP in C57BL/6J mice. Mice fed a high-fat diet supplemented with a triterpene alcohol and sterol preparation (TASP) from rice bran for 23 wk gained less weight than control mice. Indirect calorimetry revealed that fat utilization was higher in TASP-fed mice than in control mice. Fatty acid oxidation-related gene expression in the muscles of mice fed a TASP-supplemented diet was enhanced, whereas fatty acid synthesis-related gene expression in the liver was suppressed. The treatment of HepG2 cells with CA and 24Me decreased the gene expression of sterol regulatory element-binding protein (SREBP)-1c. In conclusion, we clarified for the first time that triterpene alcohols and sterols from rice bran prevented diet-induced obesity by increasing fatty acid oxidation in muscles and decreasing fatty acid synthesis in the liver through GIP-dependent and GIP-independent mechanisms.

Triterpene alcohols and sterols from rice bran reduce postprandial hyperglycemia in rodents and humans.

SCOPE Hyperglycemia is a major public health problem worldwide and there is increasing demand for prevention of postprandial hyperglycemia in diabetic, prediabetic, and healthy humans. METHODS AND RESULTS We investigated whether rice bran and triterpene alcohol and sterol preparation (TASP) lowered hyperglycemia in mice and humans. Brown rice and white rice supplemented with TASP lowered the postprandial hyperglycemia in humans. TASP and its components (cycloartenol [CA], 24-methylene cycloartanol, β-sitosterol, and campesterol) decreased postprandial hyperglycemia in C57BL/6J mice. Glucose transport into everted rat intestinal sacs and human HuTu80 cells transfected with sodium-glucose cotransporter-1 (SGLT1) was significantly reduced by the addition of CA. Intracellular localization analysis suggested that SGLT1 translocation to the apical plasma membrane was inhibited when the cells were treated with CA. CONCLUSIONS We demonstrated for the first time that TASP from rice bran lowered postprandial hyperglycemia in mice and humans. The smaller increase in blood glucose following TASP consumption may be due to the CA-induced decrease in glucose absorption from the intestine, which may be related to decreased membrane translocation of SGLT1.

Perilla extract improves frequent urination in spontaneously hypertensive rats with enhancement of the urothelial presence and anti-inflammatory effects

To investigate the effects of perilla extract on urinary symptoms in spontaneously hypertensive rats as a model of spontaneous overactive bladder.