Evaluation of apoptotic cells and immunohistochemical detection of FAS, FAS-L, Bcl-2, Bax, p53 and c-Myc in the skin of patients with chronic venous leg ulcers

In the present study we were interested, if apoptosis plays a role in the surrounding skin of venous ulcers, where microcirculatory disorders were already observed. For this purpose laser Doppler flow and partial oxygen pressure were measured in 17 patients at the ulcer edge, the transitional area of the lower leg and the thigh. Subsequently biopsies were taken from the respective sites and subjected to terminal deoxynucleotidyl transferase labelling (TUNEL) and immunohistochemistry using antibodies to determine the protein expression of Fas, Fas-L, Bax, Bcl-2, p53 and c-Myc. Laser Doppler flow was increased and transcutaneous oxygen partial pressure was decreased, with significant differences at the ulcer edge and the lower leg compared to the thigh. The skin biopsies did not show any differences when labelling for apoptotic cells. Keratinocytes of basal and spinous layer stained with antibodies against Fas, Fas-L and Bax in all probes of the three sites. c-Myc and p53 were negative in all keratinocytes of the skin probes. However, staining with Bcl-2 was significantly decreased at the ulcer edge in comparison to the lower leg and the thigh (p=0.017). Our study revealed that a disturbed microcirculation does not increase the number of apoptotic cells at the ulcer edge in patients with venous disease. The reduced staining pattern with Bcl-2 at the ulcer edge seems not to result in higher susceptibility to apoptosis, but it remains to be proven whether it is involved in epidermal acanthosis.