Role of Eosinophils in the Proliferation of Airway Smooth Muscle (ASM) Cells

Completed

Conditions: Asthma

Registration Number: NCT01082952

Lead Sponsor: King Saud University

Brief Summary: Being a key player in Asthma, eosinophils constitute a potential target to interfere with the series of biological events leading to Asthma pathogenesis. In this proposal, the investigators hypothesize that the interaction between eosinophils and airway smooth muscle cells (ASM) cells plays an important role in airway remodeling. Hence the investigators will investigate the role of eosinophils in enhancing ASM cells proliferation resulting in airways remodeling. The investigators will also investigate the mechanism behind this phenomenon. This will then pave the way for medical (drug) interference at one or several sites in order to prevent one of the main potential reasons behind airway remodeling, namely eosinophil-derived ASM proliferation.

Detailed Description: Rational and hypothesis Asthma is a chronic inflammatory disorder of the lung airways that is associated with airway remodeling and hyperresponsiveness (AHR). Its is well documented that the smooth muscle mass in asthmatic airways is increased due to hypertrophy and hyperplasia of the ASM cells. Moreover, eosinophils have been proposed in different studies to play a major role in airway remodeling. The association between increased eosinophil numbers and asthma severity has been well documented. Here, we hypothesized that the interaction between eosinophils and ASM cells plays an important role in airway remodeling and that eosinophils modulate the airways through enhancing ASM cell proliferation.

Objectives of the study The aim of this study is to examine the effect of eosinophils on ASM cell proliferation using eosinophils isolated from asthmatic subjects.

Specific aim 1. Effect of co-culture of ASM cells with eosinophils on ASM cell proliferation.

In this specific aim, the effect of eosinophil on ASM cell proliferation will be studied by co-culturing eosinophils isolated from asthmatic and healthy patients with ASM cells in vitro. This will be done using non-stimulated eosinophils or eosinophils activated with Interleukin-5 (IL-5)and Interleukin-3 (IL-3). ASM proliferation will be monitored by determining the levels of the proliferation marker Ki-67 expression in ASM cells.

Specific aim 2. Understanding the mechanism by which eosinophils enhance ASM proliferation.

In this specific aim, we will study the mechanism by which eosinophils enhance the proliferation of ASM cells. To study if this effect of eosinophils is done through direct contact with ASM cells, we will co-culture ASM cells with eosinophils membrane fractions. Moreover, we will examine the effect of cytokines and extracellular matrix (ECM) proteins produced by eosinophils on smooth muscle cells

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 12

Inclusion Criteria

Not provided

Exclusion Criteria

Not provided

Study & Design

Study Type: OBSERVATIONAL

Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
Fold Increase in ASM Proliferation Following Incubation With Eosinophils.	one day	Airway Smooth Muscle (ASM) cell proliferation was measured 24 hrs following their co-culture with eosinophil. This was determined using Ki-67 staining and flowcytometry. The fold increase in ASM proliferation was then determined.

Secondary Outcome Measures

Name	Time	Method
Fold Increase in ASM Cells Proliferation Following Treatment With Cysteinyl Leukotrienes	one day	The effect of Eosinophil release of Cysteinyl Leukotrienes on ASM proliferation was determined using blocking agents. This was determined using Ki-67 staining and flowcytometry.