Programmed cell death in nodular palmar fibromatosis (Morbus Dupuytren).

The regular loss of cellularity during involutional phase of nodular palmar fibromatosis (Morbus Dupuytren) indicates a regulated process known as programmed cell death (apoptosis). Using the TUNEL method apoptosis-related DNA fragmentation is detected in numerous cells as a characteristic feature of fibromatosis noduli of involutional phase. By means of double labelling technique, alpha-smooth muscle actin immunohistochemistry and TUNEL method for apoptosis, it is demonstrated that the cells which underwent apoptotosis are myofibroblasts. As anticipated, the antidote to apoptosis bcl-2 is not detected in involutional phase, but neither it is evidenced in proliferative phase. Immunohistochemically, Fas/APO-1 is shown to be existent in a very small number of fibroblasts in involutional phase. However, in view of the high number of TUNEL-stained cells a significance in regulating apoptosis in nodular palmar fibromatosis seems improbable. Taking into account that the development of the fibromatosis noduli, the expression of myofibroblast phenotype, basement membrane formation and growth factor expression including TGF beta culminates in involutional phase the initiation of apoptotic cell death can be discussed in relation to these growth factors and matrix protein action and the programmed cell death may be considered as the final step of myofibroblast phenotype evolution.