Bronchial Asthma and Diabetes: Impact on Bronchial Inflammation and Exercise Capacity

Overview

Type 2 diabetes is the most common form of diabetes and according to several studies, even lung can represent another target of the diabetic disease. Asthmatic patients often show comorbidities and obesity is one of the main.Several studies in literature suggest that patients with higher Body Mass Index (i.e. overweight and obese) have a greater risk of developing asthma compared to normal weight subjects. Considering inflammation, asthma is usually characterized by an increase of eosinophils in the airways and by a Th2 type inflammation, while a immunological type Th1 switch systemically characterizes diabetes. Even asthmatic patients, especially if diabetic, might have an increase of glucose in their airways, that could favourite or feed an inflammatory/infective state. Up to-day there are not in literature studies that have investigated the airways inflammatory pattern and the exercise capacity in relation to functional characteristics in diabetic patients affected by asthma.

The basic therapy for asthma treatment involves the use of corticosteroids that can lead to the development of glucose intolerance and to the onset of diabetes. Moreover, several works in literature highlight the fact that patients with diagnosis of both asthma and diabetes have a scarcer glycaemic control, a reduced life expectancy, and a higher risk of pneumonia when compared to patients with only asthma or only diabetes. However, in the last years the evaluation of the inflammatory patterns in asthmatic patients has revealed a heterogeneity of the inflammation, with patients characterized by neutrophilic phenotype, mixed granulocytic or without a well-defined inflammatory component (pauci-granulocytic phenotype).On the other side, a immunological type Th1 switch systemically characterizes diabetes. The impact of diabetes, therefore, as a comorbidity in asthmatic patients could influence the inflammatory status of airways. Moreover, studies have reported that glucose is higher in the airways of subjects affected by chronic obstructive pulmonary disease and it correlates with bacterial and viral load compared to healthy controls. Even asthmatic patients, especially if diabetic, might have an increase of glucose in their airways, that could favourite or feed an inflammatory/infective state. Although physical exercise is able to reduce the level of systemic inflammation, improving asthma symptoms and glycaemic control, it is well known that asthmatic and diabetic patients tend to lead a more sedentary life style compared to healthy subjects.A limiting factor that bonds the two pathologies is obesity, since the gain of weight causes exacerbation of respiratory symptoms, resulting in lower effort tolerance. Up to-day there are not in literature studies that have investigated the airways inflammatory pattern and the exercise capacity in relation to functional characteristics in diabetic patients affected by asthma. Aim of the study is to characterize the airways inflammatory pattern of patients affected by bronchial asthma, patients affected by type II diabetes and patients with concomitant diagnosis of asthma and diabetes by using induced sputum. Secondary objective is to characterize the exercise capacity in relation to the functional and anthropometric characteristics of patients with diabetes, with asthma and diabetes, compared to patients with only asthma.