ANALYSIS OF CELLULAR LOCATION AND CONCENTRATION IN VOCAL FOLD LAMINA PROPRIA

Studies have shown that the lamina propria plays an important role in voice production. Recent studies have analyzed the presence of differe nt proteins and quantified their extent in the lamina propria, but no similar study has yet been done on cellular makeup. The distribution o f three different cell types in the lamina propria of 22 human vocal f olds was studied. These types are fibroblasts, macrophages, and myofib roblasts. The roles of these cells in the extracellular matrix are des cribed. Their distribution was quantified with use of an image-analysi s system. We arbitrarily divided the lamina propria into five sections teach representing 20% of the lamina propria) and compared cell numbe rs among these sections. Gender comparisons were also made. From these studies it is evident that the cellular distribution in the lamina pr opria is not uniform. Fibroblasts were more abundant in the deepest 20 % of the lamina propria (p < 0.008), myofibroblasts were more abundant in the most superficial 20% (p < 0.016), and in the 36% of our sample s that contained macrophages in the lamina propria, there was a signif icantly higher number of macrophages in the first 20% of the lamina pr opria (p < 0.003). The only significant gender difference was that wom en had twice as many macrophages in the most superficial 20% of the la mina propria as men (p < 0.05). The higher myofibroblast activity in t he first 20% could indicate that the superficial layer is a region of constant repair. The increased number of macrophages in the superficia l layer likely indicates an inflammatory response to inhalants (becaus e of the role of macrophages in the inflammatory response and the fact that only 36% of the patients showed any macrophage activity at all).