Background: Adiponectin is an adipocyte-derived hormone with anti-inflammatory and insulin-sensitizing properties. Insulin resistance is a typical feature of the obstructive sleep apnea syndrome (OSAS). Objectives: Since nasal continuous positive airway pressure (nCPAP) treatment improves insulin sensitivity in patients with OSAS, we investigated serum adiponectin levels before and during nCPAP treatment to clarify possible interactions between the adiponectin levels and insulin sensitivity in patients with OSAS. Methods: Thirty nondiabetic, obese patients with OSAS (mean age 56.4 ± 11.1 years; apnoea-hypopnoea index (AHI) 46.03 ± 19.57) underwent CPAP treatment. Adiponectin levels and the levels of proinflammatory cytokines and proteins reflecting platelet activation [regulated on activation normally T cell expressed and secreted (RANTES) and soluble P-selectin (sCD62p)], as well as the insulin sensitivity index were measured before, and after 2 days and 3 months of CPAP treatment. Results: Insulin sensitivity increased significantly under nCPAP treatment, whereas adiponectin levels decreased after 2 days of nCPAP treatment, but returned to baseline levels after 3 months of nCPAP treatment. The increase in insulin sensitivity was more pronounced in patients with the highest adiponectin levels at baseline (p = 0.021) after adjustment for body fat (p = 0.003). During treatment, changes in adiponectin levels were highly predictable by the insulin sensitivity index. Conclusions: We found a significant relation between adiponectin and the insulin sensitivity index in overweight patients with OSAS. The lack of a long-lasting change in adiponectin may be explained by the overwhelming influence of the body mass index on adiponectin secretion, which was unchanged during nCPAP treatment.

The consumption of arabinoxylan, a soluble fibre fraction, has been shown to improve glycemic control in type 2 diabetic subjects. Soluble dietary fibre may modulate gastrointestinal or adipose tissue hormones regulating food intake. The present study investigated the effects of arabinoxylan consumption on serum glucose, insulin, lipids, leptin, adiponectin and resistin in subjects with impaired glucose tolerance. In a randomized, single-blind, controlled, crossover intervention trial, 11 adults consumed white bread rolls as either placebo or supplemented with 15 g arabinoxylan for 6 weeks with a 6-week washout period. Fasting serum glucose, insulin, triglycerides, unesterified fatty acids, apolipoprotein A1 and B, adiponectin, resistin and leptin were assessed before and after intervention. Fasting serum glucose, serum triglycerides and apolipoprotein A-1 were significantly lower during arabinoxylan consumption compared to placebo (p=0.029, p=0.047; p=0.029, respectively). No effects of arabinoxylan were observed for insulin, adiponectin, leptin and resistin as well as for apolipoprotein B, and unesterified fatty acids. In conclusion, the consumption of AX in subjects with impaired glucose tolerance improved fasting serum glucose, and triglycerides. However, this beneficial effect was not accompanied by changes in fasting adipokine concentrations.

Background: Heated humidifiers (HH) enable effective treatment of upper airway dryness during nasal continuous positive airway pressure (nCPAP) therapy for obstructive sleep apnoea (OSA), but the role of prophylactic use of HH during the initiation of nCPAP treatment has not been studied so far. Objectives: The aim of the present study was to investigate whether prophylactic HH during the initiation of CPAP would result in improved initial patient comfort and acceptance. Methods: In 44 consecutive, previously untreated OSA patients with no history of upper airway dryness, CPAP titration with and without HH was performed on two consecutive nights in a randomised order. The patients were interviewed after each treatment night in order to establish the comfort of the treatment, and, after the second treatment, they were asked which of the two nights they considered more pleasant, and which treatment they would prefer for long-term use. Results: Following CPAP titration with HH, 32 patients (73%) claimed to have had a better night’s sleep than usual (i.e. without CPAP treatment) compared with 33 patients (75%) saying the same following CPAP treatment without HH. For 21 patients (47.7%) treatment with HH was more pleasant, 23 (52.3%) saw no difference or said that treatment without HH was more pleasant. Nineteen patients (43.2%) gave preference to treatment with HH for long-term use, while 25 patients (56.8%) had no preference or said they would prefer treatment without HH. Conclusions: The use of HH during the initiation phase of CPAP treatment was associated neither with an initial improvement in comfort nor with greater initial treatment acceptance.

Objective: Human resistin has been stated to influence preadipocyte cell numbers and to stimulate adipocyte triglyceride lipolysis in vivo and in vitro. However, its role in human obesity remains unclear. Design: Cross-sectional study for comparisons of lean and obese subjects, and subsequent longitudinal 4-month weight loss intervention study in obese subjects. Subjects: Healthy subjects, lean (n ¼ 20, BMIo25) and overweight (n ¼ 43, BMIX25). Measurements: Serum resistin, body weight, body fat, waist-to-hip ratio, as well as markers of insulin resistance and lipid metabolism at baseline and after 4 months of intervention. Results: Serum resistin was positively correlated to HOMA-IR (partial r ¼ 0.288; P ¼ 0.055), serum fructosamines (partial r ¼ 0.280; P ¼ 0.062), serum NEFA (partial r ¼ 0.276; P ¼ 0.066) and negatively to age (partial r ¼ À0.349; P ¼ 0.019) and serum apolipoprotein A-1 (partial r ¼ À0.363; P ¼ 0.014). During the intervention, serum resistin increased significantly (Po0.001). The increase was inversely related to changes in waist-to-hip ratio (P ¼ 0.025) and positively to serum apolipoprotein B (P ¼ 0.011). In males only, the increase in resistin during weight loss was predicted by total serum cholesterol at baseline (r ¼ 0.703, P ¼ 0.007). No relation was observed between changes in resistin and changes in HOMA-IR. Conclusion: The present study indicates an association between serum resistin and markers of abdominal fat distribution as well as the regulation of lipid metabolism. However, human resistin is unlikely to play an independent role in the regulation of glucose metabolism.

Background: Manual titration of continuous positive airway pressure (CPAP) under polysomnographic control is the method most commonly employed to establish the minimal effective pressure (P_eff) for the treatment of the obstructive sleep apnoea syndrome (OSA). To date, however, the reproducibility of P_eff titrated in this way has not been investigated in any detail. Objectives: The present study aims to establish the reproducibility of P_eff determined by manual titrations of CPAP under polysomnographic control in the sleep lab. Methods: In a group of 50 patients (5 women), with a mean (SD) apnoea-hypopnoea index of 39.3 (21.8), apnoea index of 28.1 (20.9) and oxygen desaturation index of 39.3 (22.6), with newly diagnosed OSA, manual titration of CPAP was performed on two consecutive nights using the following standard titration protocol: starting at 4 mbar, CPAP was increased by steps of 1 mbar at intervals of at least 5 min, until no signs of airway obstruction could be seen, and arousals were no longer elicited. When no airway obstruction was detected over a period of 30 min, the pressure was lowered once during the night in steps of 1 mbar at intervals of at least 10 min, until obstructive events reappeared, whereupon the pressure was again increased as described above, until, once more, no signs of airway obstruction and no arousals occurred. The second titration was carried out in a blind manner, that is the lab technician did not know the results of the first pressure titration. Results: The mean (SD) P_eff for all titrations was 8.1 mbar (2.9). A high level of correlation was found between the P_eff titrated on the first night and that titrated on the second night (Spearman correlation coefficient = 0.89). In a few individual cases, however, differences of up to 3 mbar were found between P_eff on the first night and P_eff on the second night. On average, the P_eff measured on the second night was 0.5 mbar (SD = 1.3, range: –2.0 to 3.0 mbar) higher than that of the first night. Conclusions: With standardization of the manual titration of CPAP, P_eff is readily reproducible. In individual cases, however, a difference of as much as 3.0 mbar between the two titrations is possible.