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Biomedical subjects

Florian S Fuchs

Publications and source records attributed to Florian S Fuchs.

7 recordsLinked to original sources

Continuous positive airway pressure treatment rapidly improves insulin sensitivity in patients with obstructive sleep apnea syndrome.

The obstructive sleep apnea syndrome is typically associated with conditions known to increase insulin resistance as hypertension, obesity, and diabetes. We investigated whether obstructive sleep apnea itself is an independent risk factor for increased insulin resistance and whether continuous positive airway pressure (CPAP) treatment improves insulin sensitivity. Forty patients (apnea-hypopnea index > 20) were treated with CPAP. Before, 2 days after, and after 3 months of effective CPAP treatment, hyperinsulinemic euglycemic clamp studies were performed. Insulin sensitivity significantly increased after 2 days (5.75 +/- 4.20 baseline versus 6.79 +/- 4.91 micromol/kg.min; p = 0.003) and remained stable after 3 months of treatment. The improvement in insulin sensitivity after 2 days was much greater in patients with a body mass index less than 30 kg/m2 than in more obese patients. The improved insulin sensitivity after 2 nights of treatment may reflect a decreasing sympathetic activity, indicating that sleep apnea is an independent risk factor for increased insulin resistance. The effect of CPAP on insulin sensitivity is smaller in obese patients than in nonobese patients, suggesting that in obese individuals insulin sensitivity is mainly determined by obesity and, to a smaller extent, by sleep apnea.

Body Mass Index↗

Serum hyaluronate correlates with histological progression in alcoholic liver disease.

OBJECTIVES: Chronic alcohol consumption may lead to the development of liver cirrhosis. Serum concentrations of hyaluronate were suggested as a predictor in chronic liver disease, but its power to distinguish between severity of fibrosis and inflammation had not been assessed. In order to evaluate hyaluronate as a marker to detect early stages of alcoholic liver disease and to establish a possible correlation with hepatic histology, serum concentrations were measured by radioimmunoassay in 87 patients with biopsy-proven fatty liver, fatty liver and mild fibrosis, fatty liver and inflammation, severe fibrosis and inflammation, and cirrhosis, and in 12 non-alcoholic control subjects. In addition, serum hyaluronate was determined in 40 non-cirrhotic alcoholic patients with either a normal serum aspartate aminotransferase (AST) or an AST elevated at least two-fold. RESULTS: Serum hyaluronate increased significantly with advanced stages of alcoholic liver disease, while levels in patients with fatty liver were elevated only slightly without reaching significance. Hyaluronate correlated well with histological stage and was highly sensitive for detecting fibrosis in general and perivenular fibrosis as an indicator of progression to cirrhosis. Hyaluronate levels were not influenced by AST levels. CONCLUSION: Serum hyaluronate is a good predictor of the presence of even moderate hepatic fibrosis in alcoholic liver disease, justifying its clinical use to assess morphological alterations of the liver in alcoholics.

Biomarkers↗

Auto-CPAP therapy for obstructive sleep apnea: induction of microarousals by automatic variations of CPAP pressure?

STUDY OBJECTIVES: To investigate the frequency of microarousals (MA) associated with pressure changes during auto-CPAP therapy (APAP) for obstructive sleep apnea (OSA). DESIGN: Patients with OSA were studied by polysomnography during APAP therapy (Somnosmart). The MA were classified on the basis of concomitant changes in APAP pressure. SETTING: Sleep laboratory of a university hospital PARTICIPANTS: 30 patients with moderate to severe OSA. MEASUREMENTS AND RESULTS: The mean AHI during APAP was 4.7+/-4.7, the mean arousal index was 14.5+/-6.6 per hour. During epochs with a pressure variation greater than 0.5 mbar, significantly more MA occurred (0.30+/-0.17 MA per epoch) than in epochs with constant treatment pressure (0.10+/-0.054 MA per epoch; p<0.001). There were more MA during pressure-increase epochs than during pressure-decrease epochs (0.42+/-0.24 vs. 0.16+/-0.12 MA per epoch; p<0.001). 82.5 percent of the MA were not preceded by a significant change in pressure (at least 0.5 mbar within 30 sec.), 10.6% were associated with a significant prior increase and 6.9% with a significant prior decrease in pressure. The percentage of MA preceded by a significant pressure variation varied between 2.3% and 61%, with a mean of 18.9%. CONCLUSIONS: The overall frequency of MA was low, and in most individuals the relative amount of "pressure-associated MA" was not significant. However in some individuals it cannot be excluded that some additional MA may have been induced by pressure variations. Should it prove possible to prevent such "pressure-associated MA" by optimizing the regulation of APAP pressure, the overall clinical effect of APAP treatment may be improved.

Adult↗

Insulin resistance, hyperleptinemia, and obstructive sleep apnea in Launois-Bensaude syndrome.

OBJECTIVE: Launois-Bensaude Syndrome (LBS) is a very rare cause of obesity, characterized by a symmetrical accumulation of a very large number of lipomata in different regions of the body, excluding the face, the forearms, and the shanks. Obesity is known to be closely associated with insulin resistance, hyperleptinemia, and obstructive sleep apnea (OSA). We were interested in studying whether these conditions are also present in patients with obesity due to LBS with a similar frequency as in patients with "simple" truncal obesity. RESEARCH METHODS AND PROCEDURES: We performed polysomnography and hyperinsulinemic euglycemic clamp studies and measured serum leptin in three patients with LBS and in six patients with "simple" truncal obesity, matched for sex and body mass index (LBS group, 36.39 kg/m(2); controls, 35.82 kg/m(2)). RESULTS: Polysomnography revealed severe OSA in one LBS patient with marked "horsecollar lipomata." In the other LBS patients, no OSA could be demonstrated. The leptin levels of the two groups were comparable (LBS group, 36.39 microg/liter; controls, 37.18 microg/liter) and the insulin responsiveness index was also comparable in the two groups (LBS group, 3.47 micromol/kg. minute; controls, 3.79 micromol/kg. minute). DISCUSSION: Patients with LBS demonstrated similar metabolic features in terms of insulin sensitivity and hyperleptinemia as patients with "simple" truncal obesity. LBS is not strictly associated with OSA.

Adult↗

The effect of continuous positive airway pressure treatment on insulin sensitivity in patients with obstructive sleep apnoea syndrome and type 2 diabetes.

BACKGROUND: The obstructive sleep apnoea syndrome (OSA) is a frequent condition, as well as type 2 diabetes mellitus. Both diseases are characterized by insulin resistance. OBJECTIVES: The aim of this study was to establish whether OSA is an independent risk factor for increased insulin resistance in diabetics. For this purpose, we tested the hypothesis that the insulin sensitivity in patients with type 2 diabetes and OSA can be improved by 2 days or 3 months of continuous positive airway pressure (CPAP) treatment. METHODS: In 9 obese patients with type 2 diabetes and OSA [apnoea/hypopnoea index 43.1 +/- 21.3; body mass index (BMI) 37.3 +/- 5.6 kg/m2] and good glycaemic control on oral antidiabetics or on diet alone (HbA1c 6.4 +/- 0.7%), the insulin sensitivity index (ISI) was established by euglycaemic hyperinsulinaemic clamp tests at baseline, after 2 days and after 3 months of effective CPAP treatment. RESULTS: ISI was unchanged after 2 days of CPAP treatment, but was significantly improved after 3 months (4.38 +/- 2.94 vs. 2.74 +/- 2.25 at baseline; p = 0.021), without any significant changes in BMI. Glycaemic control was unaffected after 3 months (HbA1c 6.3 +/- 0.6%; not significant). Fasting leptin levels showed no significant changes. CONCLUSIONS: These results indicate that OSA itself is an independent risk factor for insulin resistance. This effect may be explained by the elevated sympathetic activity in OSA.

Continuous Positive Airway Pressure↗