الفهرس 
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Abstract
Asthma is a chronic inflammatory disorder of the airways in which many inflammatory cells and proinflammatory cytokines play a role. Asthma and obesity are common associated clinical problems, often coexisting in the same patient and the association between the two problems was suggested by many studies.
Several mechanisms have been suggested to explain the association between asthma and obesity including mechanical effects of obesity on pulmonary physiology, systemic inflammation, co-morbidities of obesity, prenatal diet and nutrition, hormonal factors, common genetic predictors and adrenergic system dysfunctions.
Beta-adrenergic receptors have been subdivided into three types: β1, β2 and β3-adrenergic receptors. However, since 1989, when β3-adrenergic receptor was cloned, its presence in various species and tissues was confirmed. They are mainly implicated in the stimulation of thermogensis and lipolysis, both in white and brown fat tissue.In turn, β3-AR was demonstrated on airways of some experimental animals.
The aim of the present work was to investigate the possible involvement of beta 3 adrenergic receptors in pathophysiology of bronchial asthma in obese subjects. The present study was conducted on 20 asthmatic patients (as defined by the ATS) and 20 non asthmatic subjects were grouped according to BMI into:10 obese patients (BMI) ≥ 30.00 kg/m and 10 normal non obese subjects (BMI) ≤ 25.00 kg/m.
The following investigations were carried out:
1) Anthropometric measurements for all subjects including body weight, body height, waist circumference and the Body Mass Index (BMI)
2) Pulmonary flow rates including: Forced expiratory volume in one second (FEV1), Forced vital capacity (FVC) and FEV1/FVC% for asthmatic and control subjects using computerized dry spirometer.
3) Measurement of lipid profile (total cholesterol, triglycerides, high density lipoprotein and low density lipoprotein), serum free fatty acids level (sFFA), serum level of uncoupling protein1 (UCP1) by ELISA technique, and the level of Adrenergic Receptor Beta3 (β3-AR) in sputum and serum.
4) Data were calculated and analyzed using the Statistical Package for Social Sciences (SPSS ver.20 Chicago, IL, USA).
Our results revealed that :
• Adrenergic beta 3 receptors already exist in both serum and sputum of obese and non obese subjects.
• The detected adrenergic beta 3 receptors in sputum in all subjects indicate the existence of these receptors in human airways and its positive significant correlation with degree of airway obstruction measured by FEV1 could suggest the possible involvement of β3-AR dysfunction in pathogenesis of asthma.
• The positive correlation between FFA, UCP1 and β3-AR in serum of obese asthmatic group could implicate for the possible existence of beta 3-mediated adipocyte low grade systemic inflammation in obese asthmatics.
• Positive significant correlations between serum and sputum β3-AR levels could suggest that such low grade inflammation could also drive airway inflammation in this group.