Distribution of dietary protein intake in daily meals influences skeletal muscle hypertrophy via the muscle clock.

The meal distribution of proteins throughout the day is usually skewed. However, its physiological implications and the effects of better protein distribution on muscle volume are largely unknown. Here, using the two-meals-per-day feeding model, we find that protein intake at the early active phase promotes overloading-induced muscle hypertrophy, in a manner dependent on the local muscle clock. Mice fed branched-chain amino acid (BCAA)-supplemented diets at the early active phase demonstrate skeletal muscle hypertrophy. However, distribution-dependent effects are not observed in ClockΔ19 or muscle-specific Bmal1 knockout mice. Additionally, we examined the relationship between the distribution of proteins in meals and muscle functions, such as skeletal muscle index and grip strength in humans. Higher muscle functions were observed in subjects who ingested dietary proteins mainly at breakfast than at dinner. These data suggest that protein intake at breakfast may be better for the maintenance of skeletal muscle mass.

Chrono-Nutrition Has Potential in Preventing Age-Related Muscle Loss and Dysfunction.

The mammalian circadian clock systems regulate the day-night variation of several physiological functions such as the sleep/wake cycle and core body temperature. Disturbance in the circadian clock due to shiftwork and chronic jetlag is related to the risk of several disorders such as metabolic syndrome and cancer. Recently, it has been thought that shiftwork increases the risk of sarcopenia which is characterized by age-related decline of muscle mass and its dysfunctions including muscle strength and/or physical performance. First, we summarize the association between circadian rhythm and the occurrence of sarcopenia and discuss its mechanistic insight by focusing on the muscle function and molecular clock gene in knockout or mutant mice. The clock gene knockout or mutant mice showed early aging phenotypes, including low survival rate and muscle loss. It suggests that improvement in the disturbance of the circadian clock plays an important role in the aging process of healthy muscles. Nutritional intake has the potential to augment muscle growth and entrain the peripheral clock. Second, we discuss the potential of chrono-nutrition in preventing aging-related muscle loss and dysfunction. We also focus on the effects of time-restricted feeding (TRF) and the distribution of protein intake across three meals.

Time-of-Day-Dependent Physiological Responses to Meal and Exercise.

The mammalian circadian clock drives the temporal coordination in cellular homeostasis and it leads the day-night fluctuation of physiological functions, such as sleep/wake cycle, hormonal secretion, and body temperature. The mammalian circadian clock system in the body is classified hierarchically into two classes, the central clock in the suprachiasmatic nucleus (SCN) of the hypothalamus and the peripheral clocks in peripheral tissues such as the intestine and liver, as well as other brain areas outside the SCN. The circadian rhythm of various tissue-specific functions is mainly controlled by each peripheral clock and partially by the central clock as well. The digestive, absorptive, and metabolic capacities of nutrients also show the day-night variations in several peripheral tissues such as small intestine and liver. It is therefore indicated that the bioavailability or metabolic capacity of nutrients depends on the time of day. In fact, the postprandial response of blood triacylglycerol to a specific diet and glucose tolerance exhibit clear time-of-day effects. Meal frequency and distribution within a day are highly related to metabolic functions, and optimal time-restricted feeding has the potential to prevent several metabolic dysfunctions. In this review, we summarize the time-of-day-dependent postprandial response of macronutrients to each meal and the involvement of circadian clock system in the time-of-day effect. Furthermore, the chronic beneficial and adverse effects of meal time and eating pattern on metabolism and its related diseases are discussed. Finally, we discuss the timing-dependent effects of exercise on the day-night variation of exercise performance and therapeutic potential of time-controlled-exercise for promoting general health.

The circadian clock is disrupted in mice with adenine-induced tubulointerstitial nephropathy.

Chronic Kidney Disease (CKD) is increasing in incidence and has become a worldwide health problem. Sleep disorders are prevalent in patients with CKD raising the possibility that these patients have a disorganized circadian timing system. Here, we examined the effect of adenine-induced tubulointerstitial nephropathy on the circadian system in mice. Compared to controls, adenine-treated mice showed serum biochemistry evidence of CKD as well as increased kidney expression of inflammation and fibrosis markers. Mice with CKD exhibited fragmented sleep behavior and locomotor activity, with lower degrees of cage activity compared to mice without CKD. On a molecular level, mice with CKD exhibited low amplitude rhythms in their central circadian clock as measured by bioluminescence in slices of the suprachiasmatic nucleus of PERIOD 2::LUCIFERASE mice. Whole animal imaging indicated that adenine treated mice also exhibited dampened oscillations in intact kidney, liver, and submandibular gland. Consistently, dampened circadian oscillations were observed in several circadian clock genes and clock-controlled genes in the kidney of the mice with CKD. Finally, mice with a genetically disrupted circadian clock (Clock mutants) were treated with adenine and compared to wild type control mice. The treatment evoked worse kidney damage as indicated by higher deposition of gelatinases (matrix metalloproteinase-2 and 9) and adenine metabolites in the kidney. Adenine also caused non-dipping hypertension and lower heart rate. Thus, our data indicate that central and peripheral circadian clocks are disrupted in the adenine-treated mice, and suggest that the disruption of the circadian clock accelerates CKD progression.

Eurotium Cristatum Fermented Okara as a Potential Food Ingredient to Combat Diabetes.

Type 2 diabetes mellitus (T2DM) is a chronic disease, and dietary modification is a crucial part of disease management. Okara is a sustainable source of fibre-rich food. Most of the valorization research on okara focused more on the physical attributes instead of the possible health attributes. The fermentation of okara using microbes originated from food source, such as tea, sake, sufu and yoghurt, were explored here. The aim of this study is to investigate fermented okara as a functional food ingredient to reduce blood glucose levels. Fermented and non-fermented okara extracts were analyzed using the metabolomic approach with UHPLC-QTof-MSE. Statistical analysis demonstrated that the anthraquinones, emodin and physcion, served as potential markers and differentiated Eurotium cristatum fermented okara (ECO) over other choices of microbes. The in-vitro α-glucosidase activity assays and in-vivo mice studies showed that ECO can reduce postprandial blood glucose levels. A 20% ECO loading crispy snack prototype revealed a good nutrition composition and could serve as a fundamental formulation for future antidiabetes recipe development, strengthening the hypothesis that ECO can be used as a novel food ingredient for diabetic management.

Effect of different sources of dietary protein on muscle hypertrophy in functionally overloaded mice.

Dietary protein intake is important for skeletal muscle protein synthesis. In this study, we investigated the differential effect of protein sources on hypertrophy of plantaris muscle induced by surgical ablation of gastrocnemius and soleus muscles. Six-week old mice were fed diets containing caseinate, whey, or soy as protein sources for 2 weeks. Plantaris muscle hypertrophy was induced by a unilateral ablation of synergistic muscles after a week. Food intake of soy protein-fed mice was higher than that of caseinate and whey-fed mice, resulting in higher body and fat weights. Plantaris muscle weight in sham-operated mice was not different across the groups. Overload-operated plantaris muscle weight and increased ratio of overloaded muscle to sham-operated muscle weights were higher in caseinate-fed mice than in whey- and soy protein-fed mice, suggesting caseinate as a promising protein source for muscle hypertrophy.

Day-Night Oscillation of Atrogin1 and Timing-Dependent Preventive Effect of Weight-Bearing on Muscle Atrophy.

BACKGROUND: Atrogin1, which is one of the key genes for the promotion of muscle atrophy, exhibits day-night variation. However, its mechanism and the role of its day-night variation are largely unknown in a muscle atrophic context. METHODS: The mice were induced a muscle atrophy by hindlimb-unloading (HU). To examine a role of circadian clock, Wild-type (WT) and Clock mutant mice were used. To test the effects of a neuronal effects, an unilateral ablation of sciatic nerve was performed in HU mice. To test a timing-dependent effects of weight-bearing, mice were released from HU for 4 h in a day at early or late active phase (W-EAP and W-LAP groups, respectively). FINDINGS: We found that the day-night oscillation of Atrogin1 expression was not observed in Clock mutant mice or in the sciatic denervated muscle. In addition, the therapeutic effects of weight-bearing were dependent on its timing with a better effect in the early active phase. INTERPRETATION: These findings suggest that the circadian clock controls the day-night oscillation of Atrogin1 expression and the therapeutic effects of weight-bearing are dependent on its timing. FUND: Council for Science, Technology, and Innovation, SIP, "Technologies for creating next-generation agriculture, forestry, and fisheries".

Effects of Meal Timing on Postprandial Glucose Metabolism and Blood Metabolites in Healthy Adults.

We examined the effects of meal timing on postprandial glucose metabolism, including the incretin response and metabolites in healthy adults. Nineteen healthy young men completed two trials involving blood collection in a fasting state and at 30, 60 and 120 min after meal provision in a random order: (1) morning (~0900 h) and (2) evening (~1700 h). The blood metabolome of eight participants was analyzed using capillary electrophoresis-mass spectrometry. Postprandial glucose concentrations at 120 min (p = 0.030) and glucose-dependent insulinotropic polypeptide concentrations (p = 0.005) at 60 min in the evening trials were higher than those in the morning trials. The incremental area under the curve values of five glycolysis, tricarboxylic acid cycle and nucleotide-related metabolites and 18 amino acid-related metabolites were higher in the morning trials than those in the evening trials (p < 0.05). Partial least-squares analysis revealed that the total metabolic change was higher in the morning. Our study demonstrates that a meal in the evening exacerbates the state of postprandial hyperglycemia in healthy adults. In addition, this study provides insight into the difference of incretion and blood metabolites between breakfast and dinner, indicating that the total metabolic responses tends to be higher in the morning.

The Role of Circadian Rhythms in Muscular and Osseous Physiology and Their Regulation by Nutrition and Exercise.

The mammalian circadian clock regulates the day and night cycles of various physiological functions. The circadian clock system consists of a central clock in the suprachiasmatic nucleus (SCN) of the hypothalamus and peripheral clocks in peripheral tissues. According to the results of circadian transcriptomic studies in several tissues, the majority of rhythmic genes are expressed in a tissue-specific manner and are influenced by tissue-specific circadian rhythms. Here we review the diurnal variations of musculoskeletal functions and discuss the impact of the circadian clock on homeostasis in skeletal muscle and bone. Peripheral clocks are controlled by not only photic stimulation from the central clock in the SCN but also by external cues, such as feeding and exercise. In this review, we discuss the effects of feeding and exercise on the circadian clock and diurnal variation of musculoskeletal functions. We also discuss the therapeutic potential of chrono-nutrition and chrono-exercise on circadian disturbances and the failure of homeostasis in skeletal muscle and bone.

The mammalian circadian clock and its entrainment by stress and exercise.

The mammalian circadian clock regulates day-night fluctuations in various physiological processes. The circadian clock consists of the central clock in the suprachiasmatic nucleus of the hypothalamus and peripheral clocks in peripheral tissues. External environmental cues, including light/dark cycles, food intake, stress, and exercise, provide important information for adjusting clock phases. This review focuses on stress and exercise as potent entrainment signals for both central and peripheral clocks, especially in regard to the timing of stimuli, types of stressors/exercises, and differences in the responses of rodents and humans. We suggest that the common signaling pathways of clock entrainment by stress and exercise involve sympathetic nervous activation and glucocorticoid release. Furthermore, we demonstrate that physiological responses to stress and exercise depend on time of day. Therefore, using exercise to maintain the circadian clock at an appropriate phase and amplitude might be effective for preventing obesity, diabetes, and cardiovascular disease.

Dietary Genistein Prevents Denervation-Induced Muscle Atrophy in Male Rodents via Effects on Estrogen Receptor-α.

BACKGROUND: Genistein has high estrogenic activity. Previous studies have shown beneficial effects of estrogen or hormone replacement therapy on muscle mass and muscle atrophy. OBJECTIVE: We investigated the preventive effects and underlying mechanisms of genistein on muscle atrophy. METHODS: In Expt. 1, male Wistar rats were fed a diet containing no genistein [control (CON)] or 0.05% genistein (GEN; wt:wt diet) for 24 d. On day 14, the sciatic nerve in the left hind leg was severed, and the right hind leg was sham-treated. In Expt. 2, male C57BL6J mice were subcutaneously administered a vehicle (Veh group) or the estrogen receptor (ER) antagonist ICI 182,780 (ICI group) via an osmotic pump for 27 d, and each group was subsequently fed CON or GEN diets from day 3 to day 27. Muscle atrophy was induced on day 17 as in Expt. 1. In Expt. 3, male C57BL6J mice were subcutaneously administered vehicle or a selective ER agonist-ER-α [4,4',4'-(4-propyl-[1H]-pyrazole-1,3,5-triyl)trisphenol (PPT)] or ER-ß [2,3-bis(4-hydroxyphenyl)-propionitrile (DPN)]-or genistein (GEN-sc-i) via an osmotic pump for 13 d, and muscle atrophy was induced on day 3 as in Expt. 1. The ratio of denervated soleus muscle weight to sham-operated soleus muscle weight (d/s ratio) was used as the index of muscle atrophy. RESULTS: Expt. 1: The d/s ratio in the GEN group was 20% higher than that in the CON group (P < 0.05). Expt. 2: The d/s ratio in the Veh-GEN group was 14% higher than that in the Veh-CON group (P < 0.05), although there was no significant difference between ICI-CON and ICI-GEN groups (P = 0.69). Expt. 3: The d/s ratio in the PPT-treated group was 20% greater than that in the Veh group (P < 0.05), but DPN and GEN-sc-i had no effect on the d/s ratio (P ≥ 0.05 compared with vehicle). CONCLUSION: Genistein intake mitigated denervation-induced soleus muscle atrophy. ER-α was related to the preventive effect of genistein on muscle atrophy.

Leucine restores murine hepatic triglyceride accumulation induced by a low-protein diet by suppressing autophagy and excessive endoplasmic reticulum stress.

Although it is known that a low-protein diet induces hepatic triglyceride (TG) accumulation in both rodents and humans, little is known about the underlying mechanism. In the present study, we modeled hepatic TG accumulation by inducing dietary protein deficiency in mice and aimed to determine whether certain amino acids could prevent low-protein diet-induced TG accumulation in the mouse liver. Mice fed a diet consisting of 3 % casein (3C diet) for 7 days showed hepatic TG accumulation with up-regulation of TG synthesis for the Acc gene and down-regulation of TG-rich lipoprotein secretion from hepatocytes for Mttp genes. Supplementing the 3 % casein diet with essential amino acids, branched-chain amino acids, or the single amino acid leucine rescued hepatic TG accumulation. In the livers of mice fed the 3 % casein diet, we observed a decrease in the levels of the autophagy substrate p62, an increase in the expression levels of the autophagy marker LC3-II, and an increase in the splicing of the endoplasmic reticulum (ER) stress-dependent Xbp1 gene. Leucine supplementation to the 3 % casein diet did not affect genes related to lipid metabolism, but inhibited the decrease in p62, the increase in LC3-II, and the increase in Xbp1 splicing levels in the liver. Our results suggest that ER stress responses and activated autophagy play critical roles in low-protein diet-induced hepatic TG accumulation in mice, and that leucine suppresses these two major protein degradation systems. This study contributes to understanding the mechanisms of hepatic disorders of lipid metabolism.

The circadian clock controls fluctuations of colonic cell proliferation during the light/dark cycle via feeding behavior in mice.

The mammalian circadian system is controlled not only by the suprachiasmatic nucleus (SCN), but also by the peripheral clocks located in tissues such as liver, kidney, small intestine, and colon, mediated through signals such as hormones. Peripheral clocks, but not the SCN, can be entrained by food intake schedules. While it is known that cell proliferation exhibits a circadian rhythm in the colon epithelium, it is unclear how this rhythm is influenced by food intake schedules. Here, we aimed to determine the relationships between feeding schedules and cell proliferation in the colon epithelium by means of immunochemical analysis, using 5-bromo-2'-deoxyuridine (BrdU), as well as to elucidate how feeding schedules influence the colonic expression of clock and cell cycle genes, using real-time reverse-transcription PCR (qRT-PCR). Cell proliferation in the colonic epithelium of normal mice exhibited a daily fluctuation, which was abrogated in Clock mutant mice. The day/night pattern of cellular proliferation and clock gene expression under daytime and nighttime restricted feeding (RF) schedules showed opposite tendencies. While daytime RF for every 4 h attenuated the day/night pattern of cell proliferation, this was restored to normal in the Clock mutant mice under the nighttime RF schedule. These results suggest that feeding schedules contribute to the establishment of a daily fluctuation of cell proliferation and RF can recover it in Clock mutant mice. Thus, this study demonstrates that the daily fluctuation of cell proliferation in the murine colon is controlled by a circadian feeding rhythm, suggesting that feeding schedules are important for rhythmicity in the proliferation of colon cells.

Long-term effects of oral L-carnitine supplementation on anemia in chronic hemodialysis.

BACKGROUND: The therapeutic role of L-carnitine (LC) on the anemia of chronic hemodialized patients is still controversial. In order to clarify the long-term effects of LC administration on renal anemia, an open, observational 12-month study was performed. METHODS: Twenty stable outpatients undergoing hemodialysis were administered LC 900 mg p.o. daily for 12 months. The recombinant human erythropoietin (rHuEPO) dose was adjusted monthly when necessary to maintain the target hemoglobin (Hb) levels. RESULTS: The free LC level increased, while the acyl/free LC ratio decreased significantly 3 months after administration and was then maintained until the end of the study. There was no difference in Hb levels and the erythropoietin resistance index (ERI) during the study period. However, it was observed that ERI decreased significantly in 7 out of 18 patients (responders) 5 months after LC administration and was maintained thereafter (almost 40% reduction of the rHuEPO dose). The acyl/free carnitine ratio at baseline was the most contributing factor distinguishing responders from nonresponders. CONCLUSION: Although the beneficial effect of LC supplementation on renal anemia was not observed in all patients, at least 40% of the patients (responders) showed a significant improvement in ERI after long-term LC administration.

The effects of oral L-carnitine supplementation on physical capacity and lipid metabolism in chronic hemodialysis patients.

BACKGROUND: It is well known that the physical activity in chronic hemodialysis patients decreases compared to that in normal subjects. In order to investigate the effects of L-carnitine on physical capacity and lipid metabolism, a cardiopulmonary exercise test using a bicycle ergometer was performed before and after 3 months of oral L-carnitine supplementation under double-blind conditions. METHODS AND RESULTS: A total of 20 stable outpatients undergoing hemodialysis treatment were randomly divided into 2 groups: controls receiving placebo and patients receiving 900 mg L-carnitine p.o. daily. The levels of free and acyl carnitine increased significantly from 22.9 ± 7.3 to 149.9 ± 51.8 µmol/l and from 16.0 ± 2.8 to 100.3 ± 50.2 µmol/l, respectively, in the L-carnitine group; however, there was no significant change in other plasma lipid profiles. The exercise time was decreased and the heart rate at the anaerobic threshold was increased in the control group 3 months after the study period, but there were no such changes observed in the L-carnitine group. The minute ventilation/CO2 output slope increased significantly from 38.9 ± 7.8 to 43.8 ± 11.8 in the L-carnitine group. It has been speculated that a shift in the energy source occurs from carbohydrate to lipid, in terms of an increase of oxygen demand. CONCLUSION: L-Carnitine supplementation might have some beneficial effects on the physical capacity of chronic hemodialysis patients due to the improvement of the lipid metabolism in the muscle.

Coffee intake mitigated inflammation and obesity-induced insulin resistance in skeletal muscle of high-fat diet-induced obese mice.

Epidemiologic findings offer the promise that coffee or its many constituents may be useful as a dietary intervention in type 2 diabetes (T2D) prevention. We aimed to elucidate the molecular mechanisms involved in the ameliorative effects of caffeinated coffee (CC), decaffeinated coffee (DC) and unroasted caffeinated green coffee (GC) on skeletal muscle gene expression profiles and their relationships in an obesity animal model. Eight-week-old male C57BL6 mice were raised for 9 weeks ad libitum on a normal diet, a high-fat diet, or high-fat diet containing 2 % freeze-dried CC, or DC, or GC. Total RNA and protein were extracted from skeletal muscle and subjected to microarray (Mouse Genome 430 2.0, Affymetrix) and western blotting analyses, respectively. Coffee intake mitigated the insulin resistance by decreasing plasma glucose levels during an insulin tolerance test and by increasing tyrosine phosphorylation of insulin receptor substrate-1 (IRS-1), p85/IRS-1 complex and pAkt/PKB (protein kinase B). In addition, coffee intake down-regulated the anti-inflammatory genes activating transcription factor 3, FBJ osteosarcoma oncogene, heat shock protein 1A, heat shock protein 1B and synuclein, gamma and the inflammation-associated insulin signaling genes stearoyl-coenzyme A desaturase 1 and secreted phosphoprotein 1. These results provide scientific insight on the probable positive effects of coffee intake on impaired insulin signaling, inflammation and obesity, thereby providing a new perspective on the prevention of obesity and T2D.

2-Deoxy-2,3-didehydro-N-acetylneuraminic acid analogs structurally modified by thiocarbamoylalkyl groups at the C-4 position: Synthesis and biological evaluation as inhibitors of human parainfluenza virus type 1.

4-O-Thiocarbamoylmethyl-Neu5Ac2en 3 has strong inhibitory activity toward human parainfluenza virus type 1 (hPIV-1) sialidase compared with the parent Neu5Ac2en 2. We synthesized analogs having thiocarbamoylethyl- 4 and thiocarbamoylpropyl group 5 at the C-4 position of 2. The inhibition degrees of 4 and 5 were weaker than that of thiocarbamoylmethyl analog 3, indicating a remarkable effect of the carbon chain length in thiocarbamoylalkyl groups at the C-4 position on inhibitory activities against hPIV-1 sialidase.