Potential role of decidual apoptosis in the pathogenesis of miscarriages

To investigate the existence and the distribution of decidual apoptosis in normal pregnancies and miscarriages (spontaneous and recurrent), a comparative immunofluorescent tissue labelling of normal control (n = 12) and miscarried pregnancies (n = 24) was designed. Evaluation of the existence and distribution of decidual apoptosis in normal pregnancies and miscarriages, characterization of the apoptotic cell types and the involvement of caspase-dependent pathways was analyzed with TUNEL, anti-active caspase-3, anti-pancytokeratin and anti-CD45 antibodies. Normal decidua showed few apoptotic cells, whereas decidua from recurrent miscarriages had a significantly higher number of apoptotic cells preferentially localized to the subepithelial and periarteriolar regions, where the onset of decidualization occurs. Apoptosis occurred via a caspase-dependent pathway. Neither immune nor epithelial cells were positively stained for any apoptotic markers. The increased number of apoptotic cells, which are strictly restricted to the periarteriolar stroma particularly in recurrent miscarriages leads us to suggest that decidual apoptosis could result a series of cellular dysfunctions that may threaten the course of pregnancy.