Autologous bone marrow transplantation in the treatment of acute myeloid leukemia: the Dartmouth experience and a review of literature

Recovery of neurological function of ischemic stroke by application of conditioned medium of bone marrow mesenchymal stem cells derived from normal and cerebral ischemia rats

Background

Several lines of evidence have demonstrated that bone marrow-derived mesenchymal stem cells (BM-MSC) release bioactive factors and provide neuroprotection for CNS injury. However, it remains elusive whether BM-MSC derived from healthy donors or stroke patients provides equal therapeutic potential. The present work aims to characterize BM-MSC prepared from normal healthy rats (NormBM-MSC) and cerebral ischemia rats (IschBM-MSC), and examine the effects of their conditioned medium (Cm) on ischemic stroke animal model.

Results

Isolated NormBM-MSC or IschBM-MSC formed fibroblastic like morphology and expressed CD29, CD90 and CD44 but failed to express the hematopoietic marker CD34. The number of colony formation of BM-MSC was more abundant in IschBM-MSC than in NormBM-MSC. This is in contrast to the amount of Ficoll-fractionated mononuclear cells from normal donor and ischemic rats. The effect of cm of BM-MSC was further examined in cultures and in middle cerebral artery occlusion (MCAo) animal model. Both NormBM-MSC Cm and IschBM-MSC Cm effectively increased neuronal connection and survival in mixed neuron-glial cultures. In vivo, intravenous infusion of NormBM-MSC Cm and IschBM-MSC Cm after stroke onset remarkably improved functional recovery. Furthermore, NormBM-MSC Cm and IschBM-MSC Cm increased neurogenesis and attenuated microglia/ macrophage infiltration in MCAo rat brains.

Conclusions

Our data suggest equal effectiveness of BM-MSC Cm derived from ischemic animals or from a normal population. Our results thus revealed the potential of BM-MSC Cm on treatment of ischemic stroke.

Acute myeloid leukemia in patients more than 50 years of age: special considerations in diagnosis, treatment, and prognosis

Although most patients with acute myeloid leukemia are more than 50 years of age and age is known to be an adverse prognostic factor, relatively few studies have been conducted to determine the optimum treatment strategy for the older patient. This report suggests that, until definitive studies are conducted in this age group, intensive chemotherapy should always be considered if the older patient's overall status and desires are consistent with this approach. Other factors, specifically cytogenetic and cell-surface marker findings, provide prognostic information, independent of age, and should also be considered during patient management.

Treatment of resistant acute myeloid leukemia

Although combination cytotoxic chemotherapy induces complete remission in 60-80% of adults with previously untreated acute myeloid leukemia, most patients will ultimately relapse and die from leukemia. Strategies which have been developed for patients with relapsed leukemia include the use of active non-cross-resistant chemotherapeutic agents, allogeneic or autologous bone marrow transplantation, or combined sequential therapy with hematopoietic growth factors and chemotherapy. Most salvage chemotherapeutic regimens use high-dose cytarabine; other agents which have activity include idarubicin, mitoxantrone, etoposide, and high-dose cyclophosphamide. Bone marrow transplantation represents the preferred approach for patients with resistant leukemia offering a likelihood of prolonged disease-free survival. Unique combinations of high-dose chemotherapy and growth factors may provide an alternative therapeutic role in the treatment of resistant leukemia.