The Basement Membrane Zone in Asthma: The Supracellular Anchoring Network.

Thickening of the basement membrane zone (BMZ) is a characteristic feature of airway remodeling in the lungs of asthmatics. However the significance of a thickened BMZ in the pathology of the asthmatic airway is not known. In this review we show that the columnar epithelium is linked to the reticular BMZ through the supracellular anchoring network. We discuss the evidence that changes in the width of the BMZ in control airways are part of a supracellular anchoring mechanism for increasing the strength of attachment between the airway epithelium and the extracellular matrix (ECM). We then review the effects of asthma on this anchoring mechanism. We conclude that both thickening of the BMZ and sloughing of columnar epithelium (creola bodies) in asthma represent abnormalities in the supracellular anchoring network attaching the airway epithelium to the ECM. Future research directed toward studying the regulation and development of the supracellular anchoring network may help better understand sloughing of columnar epithelium and the significance of reticular BMZ thickening in the asthmatic airway.