Excessive daytime napping independently associated with decreased insulin sensitivity in cross-sectional study – Hyogo Sleep Cardio-Autonomic Atherosclerosis cohort study

BackgroundAlthough excessive daytime napping has been shown to be involved in diabetes occurrence, its impact on insulin secretion and sensitivity has not been elucidated. It is speculated that excessive napping disrupts the sleep-wake rhythm and increases sympathetic nerve activity during the day, resulting in decreased insulin sensitivity, which may be a mechanism leading to development of diabetes. We previously conducted a cross-sectional study that showed an association of autonomic dysfunction with decreased insulin sensitivity, though involvement of autonomic function in the association between napping and insulin sensitivity remained unclear. Furthermore, the effects of napping used to supplement to short nighttime sleep on insulin secretion and sensitivity are also unknown. In the present cross-sectional study, we examined the relationships of daytime nap duration and autonomic function with insulin secretion and sensitivity in 436 subjects enrolled in the Hyogo Sleep Cardio-Autonomic Atherosclerosis (HSCAA) Cohort Study who underwent a 75-g oral glucose tolerance test (75-g OGTT), after excluding those already diagnosed with diabetes.MethodsDaytime nap duration was objectively measured using actigraphy, with the subjects divided into the short (≤1 hour) and long (>1 hour) nap groups. Insulin secretion and sensitivity were determined using 75-g OGTT findings. Standard deviation of normal to normal R-R interval (SDNN), a measure of autonomic function, was also determined based on heart rate variability. Subgroup analysis was performed for the associations of napping with insulin secretion and sensitivity, with the results stratified by nighttime sleep duration of less or greater than six hours.ResultsSubjects in the long nap group exhibited lower insulin sensitivity parameters (QUICKI: β=-0.135, p<0.01; Matsuda index: β=-0.119, p<0.05) independent of other clinical factors. In contrast, no associations with insulin secretion were found in either group. Furthermore, the association of long nap duration with insulin sensitivity was not confounded by SDNN. Specific subgroup analyses revealed more prominent associations of long nap habit with lower insulin sensitivity in subjects with a short nighttime sleep time (β=-0.137, p<0.05).ConclusionLong daytime nap duration may be a potential risk factor for decreased insulin sensitivity

Infection risk in hemodialysis patient

Chronic care patients undergoing hemodialysis for treatment of end-stage renal failure experience higher rates of bloodstream-associated infection due to the patients' compromised immune system and management of the bloodstream through catheters. Staphylococcus species are a common cause of hemodialysis catheter-related bloodstream infections. We investigated environmental bacterial contamination of dialysis wards and contamination of hemodialysis devices to determine the source of bacteria for these infections. All bacterial samples were collected by the swab method and the agarose stamp method. And which bacterium were identified by BBL CRYSTAL Kit or 16s rRNA sequences. In our data, bacterial cell number of hemodialysis device was lower than environment of patient surrounds. But Staphylococcus spp. were found predominantly on the hemodialysis device (46.8%), especially on areas frequently touched by healthcare-workers (such as Touch screen). Among Staphylococcus spp., Staphylococcus epidermidis was most frequently observed (42.1% of Staphylococcus spp.), and more surprising, 48.2% of the Staphylococcus spp. indicated high resistance for methicillin. Our finding suggests that hemodialysis device highly contaminated with bloodstream infection associated bacteria. This study can be used as a source to assess the risk of contamination-related infection and to develop the cleaning system for the better prevention for bloodstream infections in patients with hemodialysis

Optimum Conditions for the Assay of the Classical Pathway-Complement Titer of Tilapia (Tilupia nilotica) Serum

The optimum conditions for the assay of the classical pathway-complement titer (CH50) of tilapia serum were investigated by use of sheep red blood cells (SRBC) sensitized with tilapia antibody. The antiserum was obtained from tilapia immunized with SRBC stroma for 35 days, and heat-treated at 46℃ for 20min to inactivate the complement coexisting in the serum. The optimum conditions for the hemolytic complement reaction were found to be as follows : reaction temperature, 25℃ ; pH, 7.5-8.0 ; reaction period, 120 min ; concentrations of Ca²⁺ and Mg²⁺, 1.0 mM and 1.0 mM, respectively. Under these conditions, the CH50 of 15 tilapia specimens (240-960 g) which were obtained from a fish farm in Fukuoka City from September in 1987 to January in 1988 were assayed. The titers ranged from 153 to 392 CH50 units/ml, mean±SD being 250170 CH50 units/ml. These CH50 values of tilapia sera were extremely high as compared with those reported for other bony fishes

Plasma brain-derived neurotrophic factor and reverse dipping pattern of nocturnal blood pressure in patients with cardiovascular risk factors.

Basic studies have shown that brain-derived neurotrophic factor (BDNF) has critical roles in the survival, growth, maintenance, and death of central and peripheral neurons, while it is also involved in regulation of the autonomic nervous system. Furthermore, recent clinical studies have suggested potential role of plasma BDNF in the circulatory system.We investigated the mutual relationships among plasma BDNF, patterns of nocturnal blood pressure changes (dippers, non-dippers, extra-dippers, and reverse-dippers), and cardiac autonomic function as determined by heart rate variability (HRV).This was a cross-sectional study of patients registered in the Hyogo Sleep Cardio-Autonomic Atherosclerosis (HSCAA) Study from October 2010 to November 2012.Two-hundred fifty patients with 1 or more cardiovascular risk factor(s) (obesity, smoking, presence of cardiovascular event history, hypertension, dyslipidemia, diabetes mellitus, chronic kidney disease) were enrolled.Plasma BDNF levels (natural logarithm transformed) were significantly (p = 0.001) lower in reverse-dipper patients (7.18±0.69 pg/ml, mean ± SD, n = 36) as compared to dippers (7.86±0.86 pg/ml, n = 100). Multiple logistic regression analysis showed that BDNF (odds ratios: 0.417, 95% confidence interval: 0.228-0.762, P = 0.004) was the sole factor significantly and independently associated with the reverse-dippers as compared with dippers. Furthermore, plasma BDNF level was significantly and positively correlated with the time-domain (SDNN, SDANN5, CVRR) and frequency-domain (LF) of HRV parameters. Finally, multiple logistic regression analyses showed that the relationship between plasma BDNF and the reverse-dippers was weakened, yet remained significant or borderline significant even after adjusting for HRV parameters.Low plasma BDNF was independently associated with patients showing a reverse-dipper pattern of nocturnal blood pressure, in which an imbalance of cardiac autonomic function may be partly involved

Sleep Apnea and Physical Movement During Sleep, But Not Sleep Duration, Are Independently Associated With Progression of Left Ventricular Diastolic Dysfunction: Prospective Hyogo Sleep Cardio‐Autonomic Atherosclerosis Cohort Study

Background Although co‐occurrence of sleep disorder with heart failure is known, it is not clear whether that condition is a cause or consequence of heart failure. The present study was conducted as a longitudinal examination of the predictive value of sleep parameters on progression of left ventricular diastolic dysfunction. Methods and Results Four‐hundred fifty‐two subjects were followed for a mean of 34.7 months. An outcome of diastolic dysfunction was defined as increase in early inflow velocity/early diastolic tissue velocity >14. Sleep apnea‐hypopnea index, minimal oxygen saturation, sleep duration, and activity index (physical movement during sleep time, a potential parameter of poor sleep quality) were determined using apnomonitor and actigraphy findings, while heart rate variability was measured with a 24‐hour active tracer device. Sixty‐six of the patients developed diastolic dysfunction during the follow‐up period, with a median time of 25 months. Kaplan–Meier analysis results revealed that those with sleep apnea classified as moderate (apnea‐hypopnea index 15 to <30, P<0.01 versus none) or severe (apnea‐hypopnea index ≥30, P<0.01 versus none), and with a high activity index (Q3 or Q4, P<0.01 versus Q1), but not short sleep duration (P=0.27) had a significantly greater risk for a diastolic dysfunction event. Results of multivariable Cox proportional hazards regression analysis indicated that moderate to severe sleep apnea after a follow‐up period of 3 years (hazard ratio [HR], 9.26 [95% CI, 1.89–45.26], P<0.01) and high activity index (HR, 1.85 [95% CI, 1.01–3.39], P=0.04) were significantly and independently associated with future diastolic dysfunction. Moreover, significant association of high activity index with the outcome was not confounded by either minimal oxygen saturation or heart rate variability. Conclusions Sleep apnea and physical movement during sleep, but not sleep duration and autonomic nervous dysfunction, are independent important predictors for progression of left ventricular diastolic dysfunction

Plasma brain-derived neurotrophic factor concentration is a predictor of chronic kidney disease in patients with cardiovascular risk factors – Hyogo Sleep Cardio-Autonomic Atherosclerosis study

<div><p>Background</p><p>Brain-derived neurotrophic factor (BDNF) has been shown to have protective effects against cardiovascular diseases and death through neural and non-neural pathways via tropomyosin-related kinase B signaling. However, it is not known whether plasma BDNF concentration is a predictor of chronic kidney disease (CKD).</p><p>Design</p><p>This study was conducted as a prospective cohort study as part of the Hyogo Sleep Cardio-Autonomic Atherosclerosis.</p><p>Methods</p><p>We measured plasma BDNF concentration in 324 patients without CKD, defined as an estimated glomerular filtration rate (eGFR) less than 60 ml/min/1.73m², and with cardiovascular risk factors. As potential confounders, sleep condition, nocturnal hypertension, and autonomic function were quantitatively examined. The patients were followed for a median 37 months (range 2–59 months) and occurrence of CKD was noted.</p><p>Results</p><p>Plasma BDNF concentration was significantly and independently associated with CKD development, which occurred in 38 patients (11.7%). Kaplan-Meier analysis revealed that patients with reduced plasma BDNF concentration exhibited a significantly (p = 0.029) greater number of CKD events as compared to those with a higher concentration. Moreover, comparisons of key subgroups showed that the risk of CKD in association with low plasma BDNF concentration was more prominent in patients with a greater reduction of nocturnal systolic blood pressure, better movement index, higher standard deviations of the NN(RR) interval or average NN(RR) interval for each 5-minute period, and without past cardiovascular disease events, smoking habit, or albuminuria.</p><p>Conclusions</p><p>Plasma BDNF concentration is an independent predictor for development of CKD in patients with cardiovascular risk factors.</p></div

Plasma BDNF independently associated with reverse-dipper pattern of nocturnal blood pressure change.

<p>Multiple logistic regression analyses were performed. The covariates included age, male sex, classical cardiovascular risk factors (body mass index, current smoking, cardiovascular disease history, dyslipidemia, diabetes mellitus, eGFR), medical hypertension treatment (calcium-channel blocker, α or β blocker, ACE inhibitor or ARB, diuretic agent), AHI and BDNF. BDNF was natural logarithm-transformed (ln) to achieve a normal distribution. OR; odds ratio, CI; confidence interval, eGFR; estimated glomerular filtration rate, ACE: angiotensin converting enzyme, ARB; angiotensin receptor blocker, AHI; apnea hypopnea index, BDNF; brain-derived neurotrophic factor.</p

Clinical characteristics of subjects (n = 250).

<p>Data are presented as the mean ± standard deviation and number (%) for dichotomous variables. eGFR; estimated glomerular filtration rate, ACE; angiotensin converting enzyme, ARB: angiotensin receptor blocker, AHI; apnea hypopnea index, ABPM; ambulatory blood pressure monitoring, SBP; systolic blood pressure, DBP; diastolic blood pressure. Overall P values represent the 4-group comparison of means (ANOVA F-test) or percentage (chi-square test).</p><p>*P<0.05,</p><p>**P<0.01 vs. dippers. (post hoc test, Bonferroni correction).</p