leptin and Dyspnea

Recent data suggest that obstructive sleep apnea syndrome (OSAS) is an independent risk factor for asthma exacerbations. Neuromechanical reflex bronchoconstriction, gastroesophageal reflux, inflammation (local and systemic), and the indirect effect on dyspnea of OSAS-induced cardiac dysfunction have been suggested as mechanisms that lead to worsening asthma control in patients with concomitant OSAS. Vascular endothelial growth factor-induced airway angiogenesis, leptin-related airway changes, and OSAS-induced weight gain also may play a common mechanistic role linking both disorders. Several studies have confirmed that asthmatic patients are more prone to develop OSAS symptoms than are members of the general population. The common asthmatic features that promote OSAS symptoms are nasal obstruction, a decrease in pharyngeal cross sectional area, and an increase in upper airway collapsibility. Clarifying the nature of the relationship between OSAS and asthma is a critical area with important therapeutic implications.

Topics: Animals; Asthma; Bronchi; Bronchoconstriction; Comorbidity; Dyspnea; Gastroesophageal Reflux; Glottis; Heart Failure; Humans; Inflammation; Laryngeal Nerves; Leptin; Neovascularization, Pathologic; Reflex, Abnormal; Risk Factors; Sleep Apnea, Obstructive; Vagus Nerve; Vascular Endothelial Growth Factor A; Weight Gain

COPD is a multicomponent disease and systemic inflammation represents one of the possible mechanisms responsible for its systemic manifestations, including skeletal muscle weakness and cachexia. Fat-free mass index (FFMI) that reflects the skeletal muscle mass, has been shown to be associated with both dyspnoea and exercise capacity. We hypothesized that the multidimensional BODE index, that reflects the multicomponent nature of COPD, might be related to biomarkers of systemic inflammation. We further evaluated associations between FFMI and systemic inflammation.. BODE index and FFMI were calculated in 222 stable COPD patients and 132 smokers or ex-smokers with normal lung function. Systemic inflammation was evaluated with the measurement of leptin, adiponectin, CRP, IL-6, and TNF-α in serum samples of COPD patients.. In patients with COPD, both BODE index and FFMI presented significant positive and negative associations respectively with leptin levels (R(2) 0.61 and 0.65, respectively), whereas FFMI presented an additional negative association with the levels of TNF-α (R(2) 0.38). No significant associations were observed in smokers or ex-smokers with normal lung function.. Both BODE index and FFMI, are related to the circulating levels of leptin in patients with COPD, suggesting a possible role for leptin in the systemic component of COPD. The additional association of FFMI with TNF-α may further support a role of systemic inflammation in muscle wasting in COPD.

Topics: Aged; Biomarkers; Body Fat Distribution; Body Mass Index; C-Reactive Protein; Case-Control Studies; Cross-Sectional Studies; Dyspnea; Exercise Tolerance; Female; Forced Expiratory Volume; Humans; Interleukin-6; Leptin; Male; Middle Aged; Pulmonary Disease, Chronic Obstructive; Regression Analysis; Severity of Illness Index; Tumor Necrosis Factor-alpha