Modulation of pro- and anti-apoptotic genes in lymphocytes exposed to bonecements

The ability of bone cements to modify the apoptotic program in activated im mune cells and the mechanisms by which they act were evaluated. Mononuclear cells were collected from healthy individuals, cultured for 4 and 24 h wit h phytohemoagglutinina-P and cement extracts and then tested to assess: (a) cell viability; (b) early apoptotic events, by Annexin V/propidium iodide staining; and (c) the expression of pro- (p53, C-myc, ICE) and anti-apoptot ic (bcl-2) genes. After 4 h three cements were able to increase significantly the percentage of apoptotic cells, while after 24 h no differences were Found. The proport ion of dead cells was not significantly changed at either culture time. The simultaneous expression of both pro-apoptotic (ICE, c-myc, p53) and anti-a poptotic genes (bcl-2) was investigated only with regard to the materials w hich induced significant changes in apoptosis: two cements induced the p53 expression, while the third down-regulated bcl-2. As apoptosis regulates th e balance of immune response, the authors recommend that the interaction be tween materials and immune cells should be assessed, so that the use of pro -apoptotic materials may be avoided in patients with immune defects.