Aging impairs long-term hematopoietic regeneration after autologous stem cell transplantation.

Most of our knowledge of the effects of aging on the hematopoietic system comes from studies in animal models. In this study, to explore potential effects of aging on human hematopoietic stem and progenitor cells (HSPCs), we evaluated CD34(+) cells derived from young (<35 years) and old (>60 years) adult bone marrow with respect to phenotype and in vitro function. We observed an increased frequency of phenotypically defined stem and progenitor cells with age, but no distinct differences with respect to in vitro functional capacity. Given that regeneration of peripheral blood counts can serve as a functional readout of HSPCs, we compared various peripheral blood parameters between younger patients (≤50 years; n = 64) and older patients (≥60 years; n = 55) after autologous stem cell transplantation. Patient age did not affect the number of apheresis cycles or the amount of CD34(+) cells harvested. Parameters for short-term regeneration did not differ significantly between the younger and older patients; however, complete recovery of all 3 blood lineages at 1 year after transplantation was strongly affected by advanced age, occurring in only 29% of the older patients, compared with 56% of the younger patients (P = .009). Collectively, these data suggest that aging has only limited effects on CD34(+) HSPCs under steady-state conditions, but can be important under consitions of chemotoxic and replicative stress.

In vivo hemostatic efficacy of polyurethane foam compared to collagen and gelatin.

OBJECTIVES: Topical hemostatic agents are used in all surgical disciplines. Most of these hemostats are based on animal-derived products like collagen and gelatin. They carry the potential risk of pathogen transmission. A newly developed biodegradable, fully synthetic hemostatic agent based on polyurethane foam (PU) with 55 % polyethylene glycol (PEG) would prevent these potential risks. MATERIALS AND METHODS: The hemostatic efficacy of this new agent was compared to gelatin and collagen in humans who underwent extraction of an upper and lower molar (split-mouth model). After extraction of a molar in the maxilla and mandible, a PU foam and collagen or gelatin were inserted in the extraction socket for 2 min. Hereafter, the agents were removed and stored in ethylenediaminetetraacetic acid to stop coagulation. Then, the concentration of coagulation parameters thrombin-antithrombin III (TAT) complexes, fibrinogen, and thromboxane B2 (TxB2) in blood extracts from the agents was measured. The concentrations were also determined in baseline blood samples which were collected from the extraction socket. RESULTS: The concentrations of TAT and TxB2 were significantly increased, and fibrinogen concentration was significantly reduced compared to baseline wound blood concentrations indicating enhanced hemostasis. No significant differences were seen in the concentrations of these coagulation parameters in the three different hemostatic agents. CONCLUSIONS: These results show that PU combined with 55 % PEG is a promising alternative for the animal-derived hemostatic agents. CLINICAL RELEVANCE: The synthetic hemostatic agent could replace the animal-derived products like collagen and gelatin and therewith prevent the potential risk of pathogen transmission.

Efficacy of single-agent lenalidomide in patients with JAK2 (V617F) mutated refractory anemia with ring sideroblasts and thrombocytosis.

Patients with refractory anemia with ring sideroblasts and thrombocytosis (RARS-T) are difficult to treat because the cytoreductive treatment might be beneficial for the thrombocytosis component but harmful for the RARS component. As lenalidomide has shown to be efficacious in both myelodysplastic syndromes and myeloproliferative neoplasms, we have treated 2 RARS-T patients, who were transfusion dependent, with lenalidomide. We report the results of lenalidomide treatment in these patients and show that lenalidomide has clinical activity in this rare disorder. Both patients became transfusion independent, and 1 of the patients attained indeed a complete molecular remission.

Combined thalidomide and cyclophosphamide treatment for refractory or relapsed multiple myeloma patients: a prospective phase II study.

Thalidomide is an effective agent for patients with refractory multiple myeloma (MM) with a response rate of 30-40% at doses of 200-800 mg but with considerable side effects. We questioned whether lower doses of thalidomide in combination with a daily dose of cyclophosphamide might be an effective regimen with fewer side effects. We included 38 patients with relapsed or refractory MM. The median doses of thalidomide and cyclophosphamide were 100 and 95 mg/day, respectively. Side effects were observed in all patients, with neurotoxicity as the most troublesome. With a median follow-up of 14 months 84% of the patients responded, including 64% partial responses. The median time of progression-free survival was 30 months and the median overall survival time was 20 months. In conclusion, the results demonstrate that the combination of low-dose thalidomide with a daily dose of cyclophosphamide is an effective regimen with a high overall response rate and manageable side effects.