Novel in vitro culture and ultrastructural techniques to study the biology of myelodysplastic syndromes (MDS).

MDS is a heterogeneous clonal stem cell disorder with trilineage dysplasia resulting in ineffective, monoclonal hematopoiesis ([Resegotti et al., 1993]). Extensive studies over the decade have led to better understanding of cell proliferation, differentiation, cytokine production and apoptosis in MDS ([Greenburg et al., 1987]; [Shetty et al., 1996]; [Clark et al., 1990]; [Yoshida et al., 1993]; [Raza et al., 1995]). However there has been limited information in the literature regarding long term bone marrow cultures and ultrastructural studies performed on MDS. In the past, it has been difficult to grow MDS bone marrow (BM) cells as the progenitor cells have a great propensity to undergo programmed cell death ([Ohmori et al., 1991]; [Aizawa et al., 1999]; [Raza et al., 1996]). On the other hand the role of electron microscopy has not been clearly established in MDS either, other than few individual cases on BM aspirate because of the failure to overcome the technical impediment of maintaining the ultrastructural details in decalcified tissues ([Guccion et al., 1992]; [Gerrad et al., 1992]; [Cohen et al., 1997]; [Payne et al., 1987]). As a result very little is known about the association between the hematopoietic cells and their microenvironment especially in a disease like MDS where both the parenchymal and stromal cells may be involved in the disease process ([Coutinho et al., 1990]; [Sawada et al., 1998])). The present chapter focuses on novel techniques where primarily the MDS core bone marrow biopsy was used to maintain long term bone marrow cultures followed by ultrastructural studies, hence preserving the BM architecture and the geographical distribution of the hematopoietic and stromal cells as they existin vivo.A number of novel and interesting observations were made which are summarized here.