PROGRAMMED CELL-DEATH IN NODULAR PALMAR FIBROMATOSIS (MORBUS-DUPUYTREN)

The regular loss of cellularity during involutional phase of nodular p almar fibromatosis (Morbus Dupuytren) indicates a regulated process kn own as programmed cell death (apoptosis). Using the TUNEL method apopt osis-related DNA fragmentation is detected in numerous cells as a char acteristic feature of fibromatosis noduli of involutional phase. By me ans of double labelling technique, alpha-smooth muscle actin immunohis tochemistry and TUNEL method for apoptosis, it is demonstrated that th e cells which underwent apoptotosis are myofibroblasts. As anticipated , the antidote to apoptosis bcl-2 is not detected in involutional phas e, but neither it is evidenced in proliferative phase. Immunohistochem ically, Fas/APO-1 is shown to be existent in a very small number of fi broblasts in involutional phase. However, in view of the high number o f TUNEL-stained cells a significance in regulating apoptosis in nodula r palmar fibromatosis seems improbable. Taking into account that the d evelopment of the fibromatosis noduli, the expression of myofibroblast phenotype, basement membrane formation and growth factor expression i ncluding TGF beta culminates in involutional phase the initiation of a poptotic cell death can be discussed in relation to these growth facto rs and matrix protein action and the programmed cell death may be cons idered as the final step of myofibroblast phenotype evolution.