Cholesterol-Lowering and Antioxidant Effects of Pork-Liver Protein Hydrolysate in Otsuka Long-Evans Tokushima Fatty Rats.

In this study, we investigated the effects of a porcine liver protein hydrolysate (PLH) diet on lipid metabolism in Otsuka Long-Evans Tokushima Fatty (OLETF) rats, a model of type II diabetes. OLETF rats (20-wk-old males) were pair-fed with either a PLH diet containing 20% PLH or a casein diet for 14 wk. Dietary PLH significantly lowered serum cholesterol and phospholipid concentrations, mainly by decreasing low-density lipoprotein and high-density lipoprotein fractions. Fecal cholesterol was significantly increased in the PLH diet group; however, the total bile acid concentration in the feces was not significantly different between the groups. In addition, the PLH diet significantly decreased serum thiobarbituric acid reactive substance concentrations. These results suggest that dietary PLH exerts hyperlipidemic and antioxidant effects, indicating that it is a novel functional food ingredient.

Global thrombosis test for assessing thrombotic status and efficacy of antithrombotic diet and other conditions.

Because of the high mortality from myocardial infarction and stroke, there is a great demand for finding novel methods of diagnosis, prevention and treatment of these diseases. Most of the current tests measure important determinants of thrombosis such as platelet function, coagulation and fibrinolysis in isolation; therefore, a global test measuring the actual thrombotic status would be more useful in clinical conditions. We obtained considerable experience by using the global thrombosis test, which determines the actual thrombotic status by taking into account the measured platelet reactivity, coagulation and fibrinolytic activities. In animal experiments, we found significant correlation between the ex vivo global thrombosis test measurements and the in vivo thrombotic status. The published evidence for the benefit of an antithrombotic diet with regular physical exercise is also described.

Genistein inhibits chondrogenic differentiation and mineralization of ATDC5 cells.

Isoflavones are phytoestrogens abundant in leguminous crops and are used to prevent a variety of hormonal disorders. In the present study, the effects of genistein and daidzein on the chondrogenic differentiation of ATDC5 cells were investigated. Genistein (10 µM) treatment markedly reduced production of sulfated proteoglycans and collagen fibers in the ATDC5 cells. Genistein suppressed the expression of genes involved in chondrocyte differentiation such as Sox9, Col2a1, Col10a1, Acan, and Tgfb1. Additionally, genistein significantly decreased calcium deposition in ATDC5 cells during chondrogenic differentiation; however, it increased calcification under non-chondrogenic mineralizing conditions. Daidzein exhibited a similar effect of suppressing chondrogenesis in ATDC5 cells, although its efficacy was 10-times lower than that of genistein. These findings suggest that a high concentration of genistein inhibits chondrogenesis and chondrogenic mineralization, whereas it enhances non-chondrogenic mineralization.

Effects of Collagen Peptide Administration on Visceral Fat Content in High-Fat Diet-Induced Obese Mice.

Collagen peptides (CPs) are bioactive molecules that have beneficial effects on bone metabolism and against joint disorders. In the present study, we investigated the effect of CP supplementation on visceral fat mass and plasma lipid concentrations in high-fat diet (HFD)-induced obese mice. Male ddY mice were fed a normal diet or HFD for 3 wk, and assigned to N or NCP groups and to F or FCP groups, respectively. The NCP and FCP group mice were administered experimental diets containing 25 mg/g CPs for 3 wk further. During the experimental period, CP supplementation affected neither the food consumption nor the body weight of the mice. No significant differences in the plasma triglyceride, non-esterified fatty acid, and cholesterol concentrations were observed among all the groups. In contrast, the weight of testicular fat mass was significantly decreased in the FCP group as compared with that in the F group. The expression levels of leptin and tumor necrosis factor (TNF)-α genes in the adipose tissue correlated with the visceral fat mass, although these differences were not significant. These findings indicate that CPs may have a reducing effect on visceral fat content but are less effective in reducing body weight.

Are all wines made from various grape varieties beneficial in the prevention of myocardial infarction and stroke?

AIM: Epidemiologic studies support the assumption (French paradox hypothesis) that drinking red wine is beneficial in the prevention of cardiovascular diseases. Our recent works however cast doubt on such claim. Earlier we have shown that the antithrombotic activity of various fruits and vegetables mainly depends on their varieties. For this reason, several varieties of red and white grapes were tested for antithrombotic effect in animal experiments. RESULTS: Antithrombotic effect of 45 red and white grape varieties were assessed in the present study. Out of the 45, one red grape variety showed antithrombotic effect, while the majority of red and white grape varieties enhanced thrombosis. CONCLUSION: Most red and white grape varieties enhanced thrombotic activity of blood.

Effects of administration of glucosamine and chicken cartilage hydrolysate on rheumatoid arthritis in SKG mice.

Supplementation with cartilage constituents, such as glucosamine, chondroitin sulfate and collagen peptide, are believed to reduce pain associated with joint disorders, such as rheumatoid arthritis (RA). Here, we administered daily, 10 mg glucosamine or 100 mg chicken cartilage hydrolysate (CH) to SKG/Jcl mice, a model for spontaneous RA, for 5 weeks and evaluated their effects on RA development. In SKG mice, the administration of glucosamine had no reducing effect on RA score but suppressed the expression of Mmp13 and Col3a1 genes in articular cartilage. In contrast, administration of CH suppressed the RA score and levels of plasma interleukin-6 and interleukin-17 to half, although the differences were not significant. Mice administered with glucosamine also showed decreased bone strength of femur and these adverse effects could be eliminated when glucosamine was used in conjunction with CH. These results suggest that CH and glucosamine exert effects on different aspects in SKG mice.

Effects of a chicken collagen hydrolysate on the circulation system in subjects with mild hypertension or high-normal blood pressure.

We investigated the effects of a chicken collagen hydrolysate (CCH) on the circulation system in humans. A total of 58 subjects with either mild hypertension (systolic blood pressure (SBP) of 140-159 mmHg or diastolic blood pressure (DBP) 90-99 mmHg) or high-normal blood pressure (SBP 130-139 mmHg or DBP 85-89 mmHg) were assigned to two groups, one involving a placebo and the other, the test food (including CCH of 2.9 g/d). The parameters related to each subject's circulation system were monitored over the study period of 18 weeks. The Δbrachial-ankle pulse wave velocity (baPWV), an indicator of arterial stiffness and marker of vascular damage, was significantly lower in the test food group than in the placebo group during the treatment period. The blood pressure in the test food group was also significantly lower than that in the placebo group, while the serum nitrogen oxide was higher in the test food group after the treatment. These results suggest that CCH exerted modulatory effects on the human circulation system.

Administration of biotin prevents the development of insulin resistance in the skeletal muscles of Otsuka Long-Evans Tokushima Fatty rats.

Otsuka Long-Evans Tokushima Fatty (OLETF) rat is an animal model for type 2 diabetes mellitus. In the present study, we investigated whether pharmacologic doses of biotin have the potential to abate insulin resistance in the skeletal muscles of OLETF rats. OLETF rats (34 weeks of age) were divided into 2 groups and given distilled water (OLETF-control group) or distilled water containing 3.3 mg L(-1) of biotin (OLETF-biotin group) for 8 weeks. At the end of experimental period, the OLETF-control rats developed severe hyperglycemia and hyperinsulinemia, whereas the OLETF-biotin rats showed significantly smaller responses to oral glucose tolerance test than the OLETF-control rats. The glucose uptake in the hind limbs of the rats was significantly higher in the OLETF-biotin group than in the OLETF-control group. Biotin administration increased the glucose transporter type 4 (GLUT4) protein content in the total membrane fraction but had little effect on the GLUT4 content in the plasma membrane fraction. These results indicate that administration of a pharmacological dose of biotin prevents the development of insulin resistance in the skeletal muscles of OLETF rats presumably via an increase in GLUT4 protein expression but not via GLUT4 translocation.

Energy expenditure during 2-day trail walking in the mountains (2,857 m) and the effects of amino acid supplementation in older men and women.

We compared relative exercise intensity and active energy expenditure (AEE) on trail walking in the mountains, with those of daily exercise training, and whether branched-chain amino acid (BCAA) and arginine supplementation attenuated the release of markers indicating muscle damage and declines in physical performance. Twenty-one subjects (~63 years) were divided into two groups: amino acid (AA, 51 g of amino acids and 40 g of carbohydrate, male/female = 6/4) or placebo (PL, 91 g of carbohydrate, male/female = 6/5) supplementation during 2 days of trail walking in the mountains. We measured heart rate (HR), AEE, fatigue sensation, water and food intake, and sweat loss during walking. In addition, we measured peak aerobic capacity [Formula: see text] and heart rate (HR(peak)) with graded-intensity walking, vertical jumping height (VJ) before and after walking. We found that average HR and AEE during uphill walking were ~100% HR(peak) and ~60% [Formula: see text], while they were ~80 and ~20% during downhill walking, respectively. Moreover, average total AEE per day was sevenfold that of their daily walking training. VJ after walking remained unchanged compared with the baseline in AA (P > 0.2), while it was reduced by ~10% in PL (P < 0.01), although with no significant difference in the reduction between the groups (P > 0.4). The responses of other variables were not significantly different between groups (all, P > 0.2). Thus, trail walking in the mountains required a high-intensity effort for older people, while the effects of BCAA and arginine supplementation were modest in this condition.

Chicken collagen hydrolysate protects rats from hypertension and cardiovascular damage.

We previously reported that chicken collagen hydrolysate (CCH) has strong angiotensin I converting enzyme (ACE) inhibitory activity and antihypertensive effects on spontaneously hypertensive rats. Here, we investigated the chronic therapy effects of CCH on blood pressure and vascular relaxation in a cardiovascular damage model of Wistar-Kyoto rats induced by N-nitro-l-arginine methyl ester (L-NAME). Following co-treatment with CCH for 4 weeks, the increment of systolic blood pressure was suppressed significantly. At 8 weeks, the vasorelaxation of thoracic aorta increased significantly, and cardiovascular damage was ameliorated. The concentration of soluble intercellular adhesion molecule-1 (ICAM-1) in blood was reduced significantly by long-term administration of CCH, whereas the nitric oxide concentration was increased significantly at 1 hour post-treatment. The results suggest that beneficial effects of CCH result from antihypertensive function, but also from inhibition of cardiovascular damage to the endothelial cells via its ACE inhibitory activity and regulation of nitric oxide and ICAM-1, which suggests that CCH may be useful as a medicinal food for patients with cardiovascular disease.

Absorption and effectiveness of orally administered low molecular weight collagen hydrolysate in rats.

Collagen, a major extracellular matrix macromolecule, is widely used for biomedical purposes. We investigated the absorption mechanism of low molecular weight collagen hydrolysate (LMW-CH) and its effects on osteoporosis in rats. When administered to Wistar rats with either [(14)C]proline (Pro group) or glycyl-[(14)C]prolyl-hydroxyproline (CTp group), LMW-CH rapidly increased plasma radioactivity. LMW-CH was absorbed into the blood of Wistar rats in the peptide form. Glycyl-prolyl-hydroxyproline tripeptide remained in the plasma and accumulated in the kidney. In both groups, radioactivity was retained at a high level in the skin until 14 days after administration. Additionally, the administration of LMW-CH to ovariectomized stroke-prone spontaneously hypertensive rats increased the organic substance content and decreased the water content of the left femur. Our findings show that LMW-CH exerts a beneficial effect on osteoporosis by increasing the organic substance content of bone.

Antithrombotic papain-hydrolyzed peptides isolated from pork meat.

INTRODUCTION: Atherothrombotic disease such as coronary artery disease and stroke is one of major causes of death. Platelets play important role in these arterial diseases. Suppression of platelet activity by materials may decrease incidence of the disease. The present study aimed to examine the peptides from pork meat with antithrombotic activity. MATERIAL AND METHODS: Peptide fraction or hydrolyzate of defatted pork meat by papain was used as the starting material. Antithrombotic activity of the fraction was assessed by a share-induced platelet function test in vitro (haemostatometry) using non-anticoagulated rat blood, followed by a helium-neon laser-induced mouse carotid artery thrombosis test in vivo. RESULTS AND DISCUSSION: The starting peptide fraction with mean molecular weight 2500 showed antithrombotic activity in vivo after oral administration to mice at 210 mg/kg body weight. The fraction with mean molecular weight 2517 further purified by cation exchange chromatography showed antithrombotic activity after oral administration at 70 mg/kg body weight. Antithrombotic activity of the purified peptide fraction was equivalent to that of aspirin at 50 mg/kg body weight. It is possible this pork peptide could be beneficial to prevent atherothrombosis.

Chicken breast attenuates high-intensity-exercise-induced decrease in rat sarcoplasmic reticulum Ca2+ handling.

This study was conducted to determine whether dietary chicken-breast extract (CBEX), a rich source of histidine-containing dipeptides, could modify exercise-induced changes in sarcoplasmic reticulum (SR) function. After 5 weeks of dietary CBEX, SR Ca2+-handling ability was examined in the vastus lateralis muscles of rats subjected to high-intensity running for 2.5 min. Dietary CBEX caused an approximately 15% and 45% increase (p<.01) in muscle carnosine and anserine concentrations, respectively. In resting muscles, depressions in SR Ca2+-ATPase activity were evoked by dietary CBEX without concomitant changes in SR Ca2+ uptake and release rates. The data confirm that high-intensity exercise depresses SR Ca2+ handling. In spite of the same run time, SR Ca2+ handling was reduced to a lesser degree in muscles of CBEX-containing-chow-fed rats than in standard-chow-fed rats (p<.05). These results suggest that dietary CBEX might attenuate deteriorations in SR Ca2+-handling ability that occur with high-intensity exercise.

Effect of dietary vegetable and animal proteins on atherothrombosis in mice.

OBJECTIVE: It is believed that vegetable and fish, but not animal, proteins prevent thrombosis. The present study compared the effect of long-term intake of purified vegetable and animal proteins (casein, pork, egg white, chicken, white and red fish, soybean, and potato) and powders from whole vegetable and animal meats (soybean, pork, chicken, and horse mackerel) on thrombotic tendency. METHODS: Western-style high-fat diets with various proteins were given to mice deficient in apolipoprotein-E and low-density lipoprotein receptor for 8 or 12 wk. Thrombotic tendency was assessed by a laser-induced thrombosis test, severity of atherosclerosis was assessed by morphometric analysis of the aortic lesions, and reactivity of platelets was measured by a shear-induced platelet function test. RESULTS: There was no difference in thrombotic tendency between the vegetable and animal protein diets with the exception of pork protein, which showed a prothrombotic effect. The latter was not observed in animals kept on a high-protein diet. Thrombotic tendency was not affected by preparation of dietary powders from whole pork, chicken, or horse mackerel meats and casein (control), all of which contained the same percentages of protein and lipid. In contrast, soybean powder showed an antithrombotic effect, which was mainly due to an inhibition of atherogenesis rather than to platelet inhibition. CONCLUSION: Neither the purified animal nor the vegetable protein diet affected thrombotic tendency. Soybean powder inhibited atherothrombosis mainly by inhibiting the atherosclerotic process.

Consumption of pork-liver protein hydrolysate reduces body fat in Otsuka Long-Evans Tokushima Fatty rats by suppressing hepatic lipogenesis.

This study was performed to examine the effect of consumption of pork-liver protein hydrolysate (PLH) on body fat accumulation in Otsuka Long-Evans Tokushima Fatty (OLETF) rats as a non-insulin-dependent diabetes mellitus model and in Long-Evans Tokushima Otsuka (LETO) rats as a control. Male 20-week-old OLETF and LETO rats were pair-fed either PLH or casein containing diet for 14 weeks. In the OLETF rats, dietary PLH significantly reduced the growth and weight of fat pad including perirenal and epididymal adipose tissues. Consumption of PLH markedly suppressed hepatic activities of lipogenesis enzymes such as glucose-6-phosphate dehydrogenase and fatty acid synthase and slightly elevated fecal excretion of total fat. In the LETO rats, growth and adipose tissue weight were unaffected by dietary treatment. The results suggest that PLH is a novel ingredient suppressing body fat in genetically obese rats by reducing lipogenesis.