Effect of position therapy and oral devices on sleep parameters in patients with obstructive sleep apnea.

PURPOSE: The purpose of this study was to elucidate the effect of a neck-worn position therapy device (PTD) and oral appliance (OA) on sleep parameters in patients with obstructive sleep apnea (OSA). METHODS: Patients with an apnea hypopnea index (AHI) of 5/h or more at baseline polysomnography were divided into a PTD group and an OA group randomly. All participants underwent a type 1 polysomnography for diagnosis and device-set outcome measurements. RESULTS: The PTD decreased the AHI from a mean of 24.2/h to 16.7/h, and the OA decreased the AHI from 20.8/h to 10.3/h. Snoring duration decreased from 31.1% to 16.9% in the PTD group, and from 41.2% to 30.7% in the OA group. There were no significant differences in these decreases between the two groups. The PTD decreased sleep-time percentage in the supine position from a mean of 67.4% to 4.5%, despite five patients who were unable to avoid the supine position. There were no significant differences in improvement in sleep efficiency, percentage of stage wake, stage N1, stage N2, and stage REM, and overall arousal and respiratory arousal indices between the two groups. However, the spontaneous arousal index worsened in the OA responders but remained unchanged in the PTD responders. Percentage of stage N3 sleep (%N3) was improved in the PTD responders but not in the OA responders. There were significant differences in spontaneous arousal index and %N3 between the two groups. CONCLUSION: PTDs are a potential treatment modality that does not disturb sleep in patients with OSA.

Caloric restriction improves glucose homeostasis, yet increases cardiometabolic risk in caveolin-1-deficient mice.

BACKGROUND AND PURPOSE: The plasma membrane protein caveolin-1 (CAV-1) has been shown to be involved in modulating glucose homeostasis and the actions of the renin-angiotensin-aldosterone system (RAAS). Caloric restriction (CR) is widely accepted as an effective therapeutic approach to improve insulin sensitivity and reduce the severity of diabetes. Recent data indicate that polymorphisms of the CAV-1 gene are strongly associated with insulin resistance, hypertension and metabolic abnormalities in non-obese individuals. Therefore, we sought to determine whether CR improves the metabolic and cardiovascular (CV) risk factors in the lean CAV-1 KO mice. MATERIALS/METHODS: Twelve- to fourteen-week-old CAV-1 knockout (KO) and genetically matched wild-type (WT) male mice were randomized by genotype to one of two dietary regimens: ad libitum (ad lib) food intake or 40% CR for 4 weeks. Three weeks following the onset of dietary restriction, all groups were assessed for insulin sensitivity. At the end of the study, all groups were assessed for fasting glucose, insulin, HOMA-IR, lipids, corticosterone levels and blood pressure (BP). Aldosterone secretion was determined from acutely isolated Zona Glomerulosa cells. RESULTS: We confirmed that the CAV-1 KO mice on the ad lib diet display a phenotype consistent with the cardiometabolic syndrome, as shown by higher systolic BP (SBP), plasma glucose, HOMA-IR and aldosterone levels despite lower body weight compared with WT mice on the ad lib diet. CAV-1 KO mice maintained their body weight on the ad lib diet, but had substantially greater weight loss with CR, as compared to caloric restricted WT mice. CR-mediated changes in weight were associated with dramatic improvements in glucose and insulin tolerance in both genotypes. These responses to CR, however, were more robust in CAV-1KO vs. WT mice and were accompanied by reductions in plasma glucose, insulin and HOMA-IR in CAV-1KO but not WT mice. Surprisingly, in the CAV-1 KO, but not in WT mice, CR was associated with increased SBP and aldosterone levels, suggesting that in CAV-1 KO mice CR induced an increase in some CV risk factors. CONCLUSIONS: CR improved the metabolic phenotype in CAV-1 KO mice by increasing insulin sensitivity; nevertheless, this intervention also increased CV risk by inappropriate adaptive responses in the RAAS and BP.

Combined Salt and Caloric Restrictions: Potential Adverse Outcomes.

BACKGROUND: We hypothesized that caloric restriction (CR) and salt restriction (ResS) would have similar effects on reducing cardiovascular risk markers and that combining CR and ResS would be synergistic in modulating these markers. METHODS AND RESULTS: To test our hypothesis, rats were randomized into 2 groups: ad libitum liberal salt diet (ad libitum/high-sodium, 1.6% sodium) or ResS diet (ad libitum/ResS, 0.03% sodium). CR was initiated in half of the rats in each group by reducing caloric intake to 60% while maintaining sodium intake constant (CR/high-sodium, 2.7% sodium or CR/ResS, 0.05% sodium) for 4 weeks. CR in rats on a high-sodium diet improved metabolic parameters, renal transforming growth factor-ß and collagen-1α1 and increased plasma adiponectin and renal visfatin and NAD+ protein levels. Although CR produced some beneficial cardiovascular effects (increased sodium excretion and reduced blood pressure), it also was associated with potentially adverse cardiovascular effects. Adrenal zona glomerulosa cell responsiveness and aldosterone levels and activation were inappropriately increased for the volume state of the rodent. Like CR on HS, CR on a ResS diet also produced relative increased zona glomerulosa responsiveness and an increased blood pressure with no improvement in metabolic parameters. CONCLUSIONS: These results suggest that combining CR and ResS may decrease the beneficial effects of each alone. Furthermore, CR, regardless of dietary salt intake, inappropriately activates aldosterone production. Thus, caution should be used in combining ResS and CR because the combination may lead to increased cardiovascular risk.