In vitro growth modulation by L-ascorbic acid of colony-forming cells from bone marrow of patients with myelodysplastic syndromes

In vitro colony growth was studied on bone marrow cells from 51 patients with myelodysplastic syndromes (MDS), using a cell culture method with the unique feature of daily feeding, in an effort to gain insight into the pathophysiology of MDS and to assess the clinical utility of this cell culture assay. The colony growth pattern of MDS marrow cells is remarkably similar to that of acute myeloid leukemia but quite dissimilar from that of normal marrow, in support of a common pathophysiological mechanism for these two disorders. In particular, L-ascorbic acid (LAA) enhanced colony growth in 30% and suppressed growth in 16% of cases, a finding also similar to that in acute myeloid leukemia, indicating a unique growth requirement which may be explored for therapeutic purposes. Further, these LAA effects have prognostic value, with LAA-sensitive (both LAA-enhanced and LAA-suppressed) cases displaying shorter survivals than LAA-insensitive cases (median survival of 5 months versus 18 months; P = 0.011). This prognostic value is independent of, and more powerful than, bone marrow blasts; the median survival was 18 months for less than 5% bone marrow blasts and 8 months for greater than 5% bone marrow blasts (P = 0.044). These two risk factors can be used together to identify patients with an extremely good or an extremely poor prognosis. This study establishes the clinical usefulness of the LAA effect in MDS as a prognostic factor and provides a new lead to explore in understanding differential biochemical/molecular events and, possibly, a new therapeutic approach to the management of MDS.