Cysteine is a Biomarker For Obstructive Sleep Apnea

Thursday, February 24th, 2011 at 9:39 PM

Obstructive sleep apnea (OSA) is a risk factor for a number of cardiovascular conditions. Although homocysteine (Hcy) and cysteine (Cys) are regarded as cardiovascular risk factors, few studies have analyzed Hcy and Cys plasma concentrations in patients with Obstructive sleep apnea (OSA). The aim of this study was to evaluate the role of Hcy and Cys in Obstructive sleep apnea (OSA) in comparison with subjects without Obstructive sleep apnea (OSA)and to determine the possible influence of obesity on these variables.

Patients who submitted to polysomnography studies were recruited to engage in an 8-h fasting period for blood sample withdrawal, physical examination, ECG, and echocardiogram. A subgroup of lean patients with Obstructive sleep apnea (OSA)(BMI < 25 kg/m²) were analyzed to rule out the influence of obesity. Fifteen patients were randomly assigned to participate in a continuous positive airway pressure (CPAP) protocol to assess the influence of Obstructive sleep apnea (OSA)treatment on the obtained measurements.

A total of 75 patients and 75 control subjects matched for age and sex were analyzed. The Cys plasma levels were higher in patients with Obstructive sleep apnea (OSA) compared with control subjects (490.16 ± 67.00 ?mol/L vs 439.81 ± 76.12 ?mol/L, respectively, P < .01); however, the Hcy plasma levels did not differ between groups. Cys plasma levels were also higher in theObstructive sleep apnea (OSA) lean subgroup when compared with lean control subjects (484.21 ± 71.99 ?mol/L vs 412.01 ± 70.73 ?mol/L, respectively, P = .009). There was a significant decrease of Cys plasma levels after 6 months of CPAP effective therapy.

Cys is a potential biomarker of Obstructive sleep apnea (OSA) in obese and nonobese patients and is reduced after effective Obstructive sleep apnea (OSA) treatment.