Figure 1
From: Origins of increased airway smooth muscle mass in asthma
The potential origins of myofibroblast and ASM hyperplasia in asthmatic airways. Increased airway smooth muscle (ASM) and myofibroblast cell numbers could result from recruitment of fibrocytes from the peripheral circulation to the airway tissue; or from differentiation of tissue resident mesenchymal stem cells (MSCs); or from epithelial-mesenchymal transition (EMT) of epithelial cells. Additionally, pericytes may also contribute to this process. To transform to functioning ASM or myofibroblasts, all these cells lose their non-mesenchymal markers and acquire mesenchymal characteristics like increased α-SMA expression.