Physiological Sciences

Chronic water insufficiency induced kidney damage and energy dysregulation despite reduced food intake, which improved gut microbiota in female rats Abstract Water intake is recommended for weight loss, but the relationship between water intake and energy metabolism is not clear. We hypothesized that long-term water insufficiency would influence energy, glucose, and lipid metabolism while modulating gut microbiota. Female rats were provided with high-fat diets with different amounts of water and food intake for 6 weeks as follows: water provided for 1 h per day with food ad libitum (WRFA), water supply ad libitum plus pair feeding of with water restricted rats(WAFR), water restriction with ad libitum food for 3 weeks and water and food intake ad libitum for 3 weeks (WR-WA) and ad libitum supply of water and food (WAFA). Water intake in WRFA was about one-third of WAFR and WAFA, whereas food intake was lowered by 30% in WRFA and WAFR than WAFA. Body fat decreased in WRFA and WAFR, but WAFR decreased fat mass more than WRFA. Energy expenditure was lower in WRFA than WAFA and carbohydrate utilization was much higher in WRFA than the other groups. The peak serum glucose concentrations were lower in WAFA than the other groups and WRFA lowered serum insulin levels more than WAFA during OGTT. WRFA shrank the glomerulus with increased apoptotic cells and damaged renal tubules compared to the WAFA and WAFR. WR-WA also exhibited greater glomerular shrinkage and apoptosis that WAFA, but not as much WRFA, indicating that the kidneys were healing after water restriction damage. WRFA exacerbated dyslipidemia compared to the WAFA and WAFR groups. The gut microbiome was similarly modulated in WRFA and WAFR, compared to WAFA, but it was mainly affected by food intake, not water restriction in the host. WRFA and WAFR increased Bacteroidetes and decreased Firmicutes compared WAFA. In conclusion, chronic insufficient water intake induced renal damage, decreased energy expenditure, and exacerbated dyslipidemia in rats with reduced food intake. However, the reduction of food intake improved gut microbiome regardless of insufficient water intake and only minor effects on the microbiome were observed due to water restriction.

Natural silibinin modulates amyloid precursor protein processing and amyloid-β protein clearance in APP/PS1 mice Abstract Silibinin has been shown to attenuate cognitive dysfunction and inhibit amyloid-beta (Aβ) aggregation in Alzheimer's disease (AD) models. However, the underlying mechanism by which silibinin improves cognition remains poorly understood. In this study, we investigated the effect of silibinin on β-secretase levels, Aβ enzymatic degradation, and oxidative stress in the brains of APP/PS1 mice with cognitive impairments. Oral administration of silibinin for 2 months significantly attenuated the cognitive deficits of APP/PS1 mice in the Y-maze test, novel object recognition test, and Morris water maze test. Biochemical analyses revealed that silibinin decreased Aβ deposition and the levels of soluble Aβ1-40/1-42 in the hippocampus by downregulating APP and BACE1 and upregulating NEP in APP/PS1 mice. In addition, silibinin decreased the MDA content and increased the activities of the antioxidant enzymes CAT, SOD, and NO. Based on our findings, silibinin is a potentially promising agent for preventing AD-associated Aβ pathology.

Mild hyperbaric oxygen: mechanisms and effects Abstract Adequate oxygen supply by exposure to mild hyperbaric oxygen at appropriately high atmospheric pressure (1266–1317 hPa) and increased oxygen concentration (35–40% oxygen) has a possibility of improving the oxidative metabolism in cells and tissues without barotrauma and excessive production of reactive oxygen species. Therefore, metabolic syndrome and lifestyle-related diseases, including type 2 diabetes and hypertension, in rats were inhibited and/or improved by exposure to mild hyperbaric oxygen. It accelerated the growth-induced increase in oxidative capacity of the skeletal muscle in rats and inhibited the age-related decrease in oxidative capacity of the skeletal muscle in mice. A decrease in dopaminergic neurons in the substantia nigra of mice with Parkinson's disease was inhibited by exposure to mild hyperbaric oxygen. This review describes the beneficial effects of exposure to mild hyperbaric oxygen on some metabolic diseases and their perspectives.

Correlations between "hie-sho" interview score and progesterone, fat intake, and Kupperman index in pre- and post-menopausal women: a pilot study Abstract Japanese menopausal women who feel cold, even in a warm room, are said to be experiencing "hie-sho." We assessed the magnitude of coldness by a "hie-sho" interview score. The association between the magnitude of coldness and female hormones, fat intake, and menopausal symptoms is unknown. The aim of the present study was to elucidate the relationship between the hie-sho interview scores and female hormones, fat intake, Kupperman index in pre- (pre group) and post- (post group) menopausal women. The hie-sho interview scores, Kupperman index questionnaire results, dietary survey to analyze fat intake, and body weight were analyzed, and plasma estradiol, progesterone, and lipid levels were measured in the subjects in the pre (n = 9) and post (n = 11) groups. Plasma female hormones and fat intake were different, but the total Kupperman index was not different between pre and post groups. Plasma progesterone was positively correlated with the hie-sho score only in the post group. Plasma triglyceride was positively correlated with the hie-sho score only in the pre group. Intake of cholesterol, arachidonic acid, and docosapentaenoic acid was negatively correlated with the hie-sho score only in the pre group. The positive correlation between total Kupperman index and hie-sho score was observed only in the pre group. These results indicated that progesterone level was related to coldness in post-menopausal women. Fat intake, plasma triglyceride, and menopausal symptoms may be related to coldness in pre-menopausal women.

Muscle sympathetic nerve activity during exercise Abstract Appropriate cardiovascular adjustment is necessary to meet the metabolic demands of working skeletal muscle during exercise. The sympathetic nervous system plays a crucial role in the regulation of arterial blood pressure and blood flow during exercise, and several important neural mechanisms are responsible for changes in sympathetic vasomotor outflow. Changes in sympathetic vasomotor outflow (i.e., muscle sympathetic nerve activity: MSNA) in inactive muscles during exercise differ depending on the exercise mode (static or dynamic), intensity, duration, and various environmental conditions (e.g., hot and cold environments or hypoxic). In 1991, Seals and Victor [6] reviewed MSNA responses to static and dynamic exercise with small muscle mass. This review provides an updated comprehensive overview on the MSNA response to exercise including large-muscle, dynamic leg exercise, e.g., two-legged cycling, and its regulatory mechanisms in healthy humans.

Tabata training: one of the most energetically effective high-intensity intermittent training methods Abstract For decades, high-intensity interval/intermittent exercise training methods have been used by elite athletes to improve their performance in sports. One of the most effective training methods, i.e., 'Tabata training,' is reviewed herein from the viewpoint of the energetics of exercise. The prior research describing the metabolic profile and effects of Tabata training is also summarized, with some historical anecdotes.

Renal involvement in the pathogenesis of mineral and bone disorder in dystrophin-deficient mdx mouse Abstract Duchenne muscular dystrophy is a severe muscular disorder, often complicated with osteoporosis, and impaired renal function has recently been featured. We aimed to clarify the involvement of renal function in the pathogenesis of mineral and bone disorder in mdx mice, a murine model of the disease. We clearly revealed renal dysfunction in adult mdx mice, in which dehydration and hypercalcemia were contributed. We also examined the effects of dietary phosphorus (P) overload on phosphate metabolism. Serum phosphate and parathyroid hormone (PTH) levels were significantly increased in mdx mice by dietary P in a dose-dependent manner; however, bone alkaline phosphatase levels were significantly lower in mdx mice. Additionally, bone mineral density in mdx mice were even worsened by increased dietary P in a dose-dependent manner. These results suggested that the uncoupling of bone formation and resorption was enhanced by skeletal resistance to PTH due to renal failure in mdx mice.

Renin–angiotensin system research: from molecules to the whole body Abstract Hypertension is one of the most important risk factors and a leading cause of death from cardiovascular and cerebrovascular diseases. Based on numerous previous studies, hypertension is thought to be caused by the complex mutual interactions of genetic factors and environmental factors, such as excessive salt intake and stress. However, its detailed mechanisms are not yet clearly understood. The renin–angiotensin system (RAS) is a key hormonal system in the pathogenesis of hypertension. New knowledge is still accruing on this cascade, even after more than 120 years since the discovery of renin. To clarify the molecular mechanisms of RAS in vivo, we created transgenic mice with chronic hypertension. These mice carry the human genes encoding renin, a hypertensive enzyme, and its substrate angiotensinogen. Hypotensive mice homozygous for a targeted disruption of the angiotensinogen gene were also created. This review presents our 47-year history of RAS research.

Sodium-coupled monocarboxylate transporter 1 interacts with the RING finger- and PDZ domain-containing protein PDZRN3 Abstract Sodium-coupled monocarboxylate transporter SMCT1 (SLC5A8) mediates monocarboxylate transport in the proximal tubule of the kidney. We have identified PDZK1 and PDZ domain-containing RING finger 3 (PDZRN3) as potent binding partners of SMCT1, which has a PDZ motif (Thr–Arg–Leu), by yeast two-hybrid screening and revealed that PDZK1 enhances the transport activity of SMCT1. In this study, we aimed to characterize the interaction between SMCT1 and PDZRN3 as well as to examine how PDZRN3 regulates SMCT1 function. An interaction between SMCT1 and PDZRN3 through the PDZ motif was observed in a co-immunoprecipitation assay and yeast two-hybrid assay. A transport assay showed that PDZRN3 abolished the enhancing effect of PDZK1 on nicotinate uptake via SMCT1. Our results suggest that SMCT1 interacts with PDZRN3 and that PDZRN3 may regulate SMCT1 function by interfering with the interaction between SMCT1 and PDZK1.

Enhancement of electroencephalogram activity in the theta-band range during unmatched olfactory-taste stimulation Abstract The aim of this study was to investigate how odor stimulation affects taste perception. Electroencephalogram (EEG) signals were measured from the frontal region of the head in normal, healthy subjects, and frequency analyses were performed. Each odor stimulation was delivered while the subject was tasting chocolate, using chocolate paste as the odorant for 'matched odor stimulation,' and garlic paste for 'unmatched odor stimulation.' Differences in EEG signals appeared between the matched and unmatched arms of the study. Comparison of the frequencies of EEGs captured under the condition of unmatched odor stimulation with those captured under the condition of matched odor stimulation showed that the occupancy rate of the theta-frequency band under the condition of unmatched odor stimulation was higher than that under the condition of matched odor stimulation. Interestingly, a negative correlation existed between the occupancy rate of the theta-frequency band and the subjective feeling of chocolate sweetness. The present findings suggest that when humans receive odors that do not match with the foods being consumed, subjective feelings are disturbed and theta-band brain activity is increased while the unmatched information is cross-checked.

Alexandros Sfakianakis
Anapafseos 5 . Agios Nikolaos
Crete.Greece.72100
2841026182

6948891480

alsfakia@gmail.com