Low-Volume Leukapheresis in Non-Cytokine-Stimulated Donors for the Collection of Mononuclear Cells.

BACKGROUND: There is an increasing demand for products containing mononuclear cells (MNCs) for cellular immune therapy. Hence, leukapheresis is increasingly performed in healthy volunteer donors. METHODS: We evaluated 147 low-volume leukapheresis procedures from 77 healthy non-cytokine-stimulated donors. Complete blood counts (CBCs) of the donors were measured before and directly after the procedures as well as from the MNC products. Follow-up CBCs were collected from donors within 21 days. RESULTS: The product hematocrit within a range from 1.2 to 6.0% did not correlate with the collection efficiency of any cell population or the granulocyte and platelet yield. There was a strong correlation between the CBC values before leukapheresis and the cell yield of lymphocytes and monocytes as well as a perfect negative correlation between cell recruitment and cell loss in all cell populations. Furthermore, we observed a significant decrease in the CBC values in all cell populations directly after leukapheresis, which recovered within a mean of 16.1 days (SD ± 2.1 days) and even showed a significant increase in granulocytes and platelets. CONCLUSION: Low-volume leukapheresis is feasible for the collection of MNCs in which the product hematocrit is negligible for the collection efficiency, cell yield, or contamination of residual cells under operational settings recommended by the manufacturer. Our data suggests that cell recruitment is regulated by the number of cells removed, which may also be the stimulus to induce granulo- and thrombopoiesis within the first days after leukapheresis.

Orchestration of Chemomobilization and G-CSF Administration for Successful Hematopoietic Stem Cell Collection.

Successful collection of peripheral blood stem cells (PBSCs) depends on the optimal orchestration of mobilization chemotherapy, granulocyte colony stimulating factor (G-CSF) application, and CD34+ cell number assessment in the peripheral blood (PB). However, determining the optimal timing in accordance to the applied chemomobilization regimen can be challenging. Although most centers apply their own local timing schedules, a reliable timetable including the currently most often used mobilization regimens is lacking. We present a comprehensive analysis of the timing modalities for 11 of the most commonly used chemomobilization regimens. A retrospective analysis was performed on the clinical and PBSC collection parameters (including duration of G-CSF application, time point of CD34+ assessment, PB CD34+ cell count, number of leukapheresis [LP] sessions, processed blood volume, and CD34+ collection results) of 91 representatively selected patients who had undergone stem cell mobilization at 2 collection centers. Six to 10 patients were analyzed per regimen with a variety of diagnoses, including multiple myeloma, malignant lymphoma, and sarcoma. No collection failures (<2 × 106 CD34+ cells/kg body weight) were observed. All analyzed patients successfully reached their individual collection goal in adherence to the given schedule of chemotherapy, application of G-CSF, measurement of CD34+ cells, and subsequent LP. The presented data on the timing of chemomobilization, G-CSF application, and stem cell collection may be helpful in clinical decision making and contribute to a more transparent and predictable treatment process.

Wnt signaling is critical for maladaptive cardiac hypertrophy and accelerates myocardial remodeling.

The evolutionary conserved Wnt signaling pathway regulates cardiogenesis. However, members of the Wnt pathway are also expressed in the adult heart. Although Wnt-signaling is quiescent under normal conditions, we noticed activation on pathological stress of the heart, such as chronic afterload increase. To examine the role of Wnt signaling on the postnatal heart, we modified the expression and function of the Wnt regulator dishevelled 1 (Dvl-1) both in transgenic mice with cardiac-specific overexpression of Dvl-1 (Dvl-1-Tg) and in cultured cardiac myocytes. Dvl-1-Tg mice (3 months) had severe cardiac hypertrophy (heart weight:body weight ratio: 5.2+/-0.3 mg/g wild-type [WT] versus 6.4+/-0.7 mg/g Dvl-1-Tg; P<0.01), an increase in cardiomyocyte size (86% increase in Dvl-1-Tg compared with WT; P<0.01) and marked raise of atrial natriuretic factor expression (12-fold increase versus WT; P<0.01). Hypertrophy was associated with left ventricular dilatation in Dvl-1-Tg and a reduction of ejection fraction (4.4+/-0.1 mm versus 5.5+/-0.2 mm, 80+/-2% and 43+/-4% in WT versus Dvl-1-Tg, respectively; P<0.01). Transgenic animals died prematurely before 6 months of age. Both canonical as well as noncanonical Wnt signaling branches were activated in the Dvl-1-Tg animals. Small interfering RNA-mediated depletion of Dvl-1 was used to further characterize the role of Dvl-1 in cardiac myocytes. Whereas baseline parameters were unaltered, beta-adrenergic hypertrophic response was abrogated in Dvl-1 knockdown cardiac myocytes, indicating a mandatory role in beta-adrenergic stimulation. Therefore, activation of Wnt signaling is sufficient and critical for the induction of myocardial hypertrophy and cardiomyopathy.