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.

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".

Role of vitamin D in energy and bone metabolism in postmenopausal women with type 2 diabetes mellitus: A 6-month follow-up evaluation.

AIMS/INTRODUCTION: Resting energy expenditure was associated with a serum bone turnover marker in postmenopausal women with type 2 diabetes (T2DMPW) in the present cross-sectional study. To clarify the fundamental pathological factor for the correlation of bone metabolism and basal metabolism in type 2 diabetes, a 6-month prospective follow-up study was carried out with supplementation of vitamin D. MATERIALS AND METHODS: A total of 44 T2DMPW were enrolled. The following factors were evaluated at the beginning and the end of the summer: procollagen type 1 N-terminal propeptide, carboxy-terminal collagen crosslinks-1, intact parathyroid hormone and 25-hydroxyvitamin D (25[OH]D), as well as diabetic complications, body composition, respiratory quotient and resting energy expenditure. A total of 23 patients with low 25(OH)D levels (˂20 ng/mL) were instructed to increase vitamin D levels by lifestyle change. Among them, 15 patients with osteoporosis were also administered alfacalcidol. RESULTS: Serum 25(OH)D increased in 25 patients and decreased in 19 patients. Patients who did not receive the study intervention at the start tended to have a decreased 2525(OH)D level; therefore, the average 25(OH)D level of all patients was not changed. Changes in resting energy expenditure were positively correlated with those of procollagen type 1 N-terminal propeptide/carboxy-terminal collagen crosslinks-1. Changes in the respiratory quotient correlated with the mean glycated hemoglobin levels; procollagen type 1 N-terminal propeptide levels positively correlated with serum 25(OH)D after the intervention. These correlations were prominent in patients with increased 25(OH)D and those with alfacalcidol supplementation. CONCLUSIONS: Restoration of vitamin D level might be a prerequisite for a normal correlation between bone and basal metabolism in T2DMPW. Lifestyle intervention for retention of vitamin D level is important even in summer, in T2DMPW.

Antihypertensive and metabolic effects of hydrochlorothiazide versus amlodipine when added to losartan in patients with type 2 diabetes.

We performed a prospective, randomized, multicenter, parallel-group, per-protocol study to compare the effects of hydrochlorothiazide (HCTZ) and amlodipine as add-on to losartan treatment in hypertensive type 2 diabetic patients. A total of 49 Japanese type 2 diabetic patients with inadequate control of blood pressure while receiving losartan 50 mg were randomly allocated to receive a fixed-dose single-pill combination of HCTZ 12.5 mg plus losartan (N = 26) or a free combination of amlodipine 5 mg plus losartan (N = 23). During 8 weeks of follow-up, changes in blood pressure and laboratory data including HbA1c, uric acid, and potassium were compared between the groups using analysis of covariance. Systolic and diastolic blood pressure decreased in both groups, the reductions of which were greater in the amlodipine group. However, the least square mean (95 % CI) differences between groups were not statistically significant [2.3 (-6.8 to 11.4) mmHg, p = 0.618 and 2.7 (-2.4-7.9) mmHg, p = 0.293, respectively]. HbA1c increased in patients receiving HCTZ but not in the amlodipine group. Uric acid also increased in patients receiving HCTZ but decreased in patients receiving amlodipine, yielding a significant between-group difference of 1.0 (0.5-1.5) mg/dl (p < 0.001). No intra- or intergroup change was observed in serum potassium levels. This pilot study suggests that HCTZ and amlodipine result in nonsignificant effects on systolic and diastolic blood pressure reduction when administrated as add-on therapy to losartan in hypertensive patients with type 2 diabetes; however, addition of HCTZ may be associated with less favorable effects on metabolic profiles than amlodipine.

Association between basal metabolic function and bone metabolism in postmenopausal women with type 2 diabetes.

OBJECTIVE: Diabetes is a risk factor for osteoporosis, and glycemic control is critical during osteoporosis treatment in patients with type 2 diabetes (T2D). However, diabetic therapies have potentially adverse effects on bone metabolism. Additionally, biomarkers for bone metabolism are directly affected by drug therapies for osteoporosis. This study examined resting energy expenditure (REE) and respiratory quotient (RQ) as indices of bone metabolism in postmenopausal Japanese women with T2D. METHODS: Forty-six postmenopausal Japanese women with T2D were examined. Procollagen type 1 N-terminal propeptide (P1NP, a fasting serum bone formation marker) and carboxy-terminal collagen cross-links-1 (CTX-1, a resorption marker) were evaluated, along with intact parathyroid hormone, 25-hydroxyvitamin D (25[OH]D), urine microalbumin, motor nerve conduction velocity, sensory nerve conduction velocity, R-R interval, body composition, REE, RQ, and bone mineral density at the nondominant distal radius. RESULTS: The mean T-score was low with high variance (-1.7 ± 1.6), and 18 patients (39%) met the criteria for osteoporosis. REE was positively correlated with body mass index (ß = 0.517; r(2) = 0.250), serum calcium (ß = 0.624; r(2) = 0.200), glycated hemoglobin A1C for the previous 6 mo (ß = 0.395; r(2) = 0.137), and the serum P1NP/CTX-1 ratio (ß = 0.380; r(2) = 0.144). RQ was positively correlated with serum 25(OH)D (ß = 0.387; r(2) = 0.131). CONCLUSION: The basal metabolic rate and diabetic pathophysiology are interrelated with bone turnover.

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.

Effects of tryptophan-rich breakfast and light exposure during the daytime on melatonin secretion at night.

BACKGROUND: The purpose of the present study is to investigate effects of tryptophan intake and light exposure on melatonin secretion and sleep by modifying tryptophan ingestion at breakfast and light exposure during the daytime, and measuring sleep quality (by using actigraphy and the OSA sleep inventory) and melatonin secretion at night. METHODS: Thirty three male University students (mean ± SD age: 22 ± 3.1 years) completed the experiments lasting 5 days and 4 nights. The subjects were randomly divided into four groups: Poor*Dim (n = 10), meaning a tryptophan-poor breakfast (55 mg/meal) in the morning and dim light environment (<50 lx) during the daytime; Rich*Dim (n = 7), tryptophan-rich breakfast (476 mg/meal) and dim light environment; Poor*Bright (n = 9), tryptophan-poor breakfast and bright light environment (>5,000 lx); and Rich*Bright (n = 7), tryptophan-rich breakfast and bright light. RESULTS: Saliva melatonin concentrations on the fourth day were significantly lower than on the first day in the Poor*Dim group, whereas they were higher on the fourth day in the Rich*Bright group. Creatinine-adjusted melatonin in urine showed the same direction as saliva melatonin concentrations. These results indicate that the combination of a tryptophan-rich breakfast and bright light exposure during the daytime could promote melatonin secretion at night; further, the observations that the Rich*Bright group had higher melatonin concentrations than the Rich*Dim group, despite no significant differences being observed between the Poor*Dim and Rich*Dim groups nor the Poor*Bright and Rich*Bright groups, suggest that bright light exposure in the daytime is an important contributor to raised melatonin levels in the evening. CONCLUSIONS: This study is the first to report the quantitative effects of changed tryptophan intake at breakfast combined with daytime light exposure on melatonin secretion and sleep quality. Evening saliva melatonin secretion changed significantly and indicated that a tryptophan-rich breakfast and bright light exposure during the daytime promoted melatonin secretion at this time.

Change in sleep state of the elderly before and after cataract surgery.

It seems likely that the influences of light upon circadian rhythms will decrease with aging, particularly those rhythms that are more influenced by light with a higher color temperature and richer in short wavelengths. More specifically, cataract patients' optical systems transmit light poorly, especially the shorter wavelengths that affect the circadian system more. The present study investigated melatonin secretion profiles and sleep patterns before and after cataract surgery. Fifteen subjects were studied for 3 consecutive weekdays before, and one month after, their cataract surgery. UV-cutting intra-ocular lenses were used for patients after surgery. No statistically significant differences between before and after surgery were observed in the amount of light received and the amount of activity. This means that there were no significant changes in their lifestyle during the experimental period. Considering the group as a whole, no significant differences were present in melatonin secretion, sleep parameters, or sleepiness before and after the surgery. However, individual subjects responded differently. The subjects showed a negative correlation between the wake-up (p=0.067) or retiring times (p=0.017) and sleep efficiency after surgery. The amount of light received during the nighttime influenced sleep more significantly than during the daytime.

Asymmetric dimethylarginine is closely associated with the development and progression of nephropathy in patients with type 2 diabetes.

BACKGROUND: Nitric oxide (NO) is thought to play an important role in the pathogenesis of diabetic nephropathy. We conducted a prospective, observational cohort study to explore the relationship between plasma levels of asymmetric dimethylarginine (ADMA), an endogenous inhibitor of NO synthase, and the development and progression of nephropathy in patients with type 2 diabetes. METHODS: This was a hospital-based observational cohort study in Japanese type 2 diabetic patients with normoalbuminuria [urinary albumin-to-creatinine ratio (ACR) <30 mg/g creatinine] or microalbuminuria (30 < or = ACR <300 mg/g creatinine). The primary endpoint was the development or progression of diabetic nephropathy, based on transition from any given stage to a more advanced stage of albuminuria. RESULTS: We studied 225 diabetic patients, 81 women and 144 men, with a mean (+/-SD) age of 64 +/- 10 years. The majority (183) of patients were normoalbuminuric, with the remainder microalbuminuric (42). During the median follow-up period of 5.2 years, 27 normoalbuminuric and 10 microalbuminuric patients reached the primary endpoint. When patients were separated according to the median ADMA level (0.46 mumol/l), patients with higher ADMA levels had a greater incidence of reaching the endpoint (P = 0.014 by the log-rank test). In the multivariate Cox proportional hazard model, the hazard ratio for reaching the endpoint for patients with higher versus lower ADMA levels was 2.72 (95% confidence interval 1.25-5.95; P = 0.012). CONCLUSIONS: Higher plasma levels of ADMA may be a novel and potent predictor of the progression of nephropathy in adult Japanese type 2 diabetic patients.

Pulse pressure and chronic kidney disease in patients with type 2 diabetes.

To determine the association between both age and degree of albuminuria and pulse pressure in patients with type 2 diabetes, we conducted this study consisting of two cross-sectional observations. A total of 833 ambulatory and 107 hospitalized type 2 diabetic patients with serum creatinine <2.00 mg/dl were studied. Systolic blood pressure (SBP), diastolic blood pressure (DBP), and pulse pressure (PP) were compared among ambulatory patients stratified according to the degree of albuminuria, as well as according to age at 10-year intervals. In the hospitalized patients, 24-h blood pressure was monitored, and 24-h SBP, DBP, and PP were correlated with aortic pulse wave velocity (PWV) and mean intima-media thickness (IMT) of the carotid arteries. In the ambulatory patients, SBP and PP were greater in patients with microalbuminuria and clinical albuminuria, as well as in the older groups, whereas DBP tended to be lower in the older age groups. Multiple regression analysis adjusted for covariates including age indicated that increased albuminuria was independently associated with greater PP (p < 0.001). In the hospitalized patients, stepwise increases were observed in SBP and PP (daytime, nighttime and overall 24-h), but not in DBP, in microalbuminuric and albuminuric patients. SBP and PP were positively and DBP was negatively associated with aortic PWV; however, no association was found with IMT. In conclusion, PP is closely associated with higher age, degree of albuminuria, and large artery stiffness in patients with type 2 diabetes.

Central distribution of neuronal cell bodies innervating the levator veli palatini muscle and associated pattern of myosin heavy chain isoform expression in rat.

The levator veli palatini (LVP) is a muscle that plays a very important role in the complex functions regulating velopharyngeal function. Although previous studies have indicated that the contraction properties of the LVP closely resemble those of the intrinsic laryngeal muscle, histological evidence has not yet been obtained. The LVP is generally considered to be innervated by the glossopharyngeal nerve, which contains efferent and afferent components. LVP motoneurons are localized in the nucleus ambiguus (Amb), and afferent neurons project into the bilateral regions of the nucleus of the solitary tract (NST). However, the position of neuronal cell bodies on afferent neurons has remained unknown. The present study examined serial muscle cross-sections using monoclonal antibodies specific for myosin heavy chain (MyHC), to characterize muscle fibers of the LVP, clarify the central distribution of LVP motoneurons within the Amb and afferent terminals within the NST, and elucidate the location of LVP afferent neuronal cell bodies. Clear separation was observed within the LVP between fibers containing only fast MyHC and others positive for both slow and fast MyHC. Horseradish peroxidase (HRP)-labeled motoneurons in the Amb were separated into rostral and caudal divisions, corresponding to the Bötzinger complex and the rostral ventral respiratory group, respectively. HRP-labeled afferent neuronal cell bodies were observed in a glossopharyngo-vagal complex ganglion, and HRP-labeled afferent terminals were observed in bilateral lateral regions of the NST. These results suggest a relationship between MyHC isoform expression and the central distribution of LVP motoneurons or central projections of afferent neurons, with regard to activity of the LVP during both inspiration and expiration.

The distribution of respiration-related and swallowing-related motoneurons innervating the rat genioglossus muscle.

The present study was an attempt to identify the location of genioglossal respiratory and swallowing motoneuron cell bodies within the hypoglossal (XII) nucleus using both electrophysiological and morphological studies. The genioglossus muscle is innervated by the genioglossal branch of the medial XII nerve. At the entrance to the muscle, the genioglossal branch divides in the directions of the mandible and tongue. Five of five rats displayed both respiratory-related and swallowing-related bursts in the medial XII branch towards the mandible. All five rats also displayed swallowing-related bursts in the medial XII branch towards the tongue. In addition, horseradish peroxidase conjugated to wheatgerm agglutinin (HRP:WGA) was injected into the proximal cut ends of each branch. When HRP:WGA was injected into the branch in the direction of the mandible, HRP-labeled cells were detected in the lateral region of the ventromedial subnucleus in the XII nucleus, extending from 0.7 to 1.2 mm rostral to the obex. On the other hand, after injection into the branch in the direction of the mandible, HRP-labeled cells were detected in the ventromedial subnucleus of the XII nucleus, extending from 0.3 to 1.2 mm rostral to the obex. These results provide evidence that genioglossal respiration-related and swallowing-related motoneurons are located in different portions within the ventromedial subnucleus of the XII nucleus.