Erkan Maytalman

Human bone marrow mesenchymal cells express NG2: possible increase in discriminative ability of flow cytometry during mesenchymal stromal cell identification

BACKGROUND AIMS Mesenchymal stromal cells (MSC) exhibit non-specific hematopoietic cell and/or stromal cell markers (e.g. CD73, CD105 and CD166) that have been used to identify MSC by flow cytometry. Because a neural glial antigen, NG2 (a progenitor cell marker in the central nervous system), is expressed by several tissue cells originating in the mesenchyme but not hematopoietic cells, it might be useful for isolating and identifying MSC. We investigated NG2 expression on culture-expanded MSC by flow cytometry. METHODS Human bone marrow (BM) samples taken from 12 donors were cultured for MSC to be used in up to nine serial passages. Using flow cytometry, the neural glial antigen NG2 and commonly used MSC markers CD73, CD105 and CD166, were analyzed on the surface of culture-expanded MSC. The multipotential differentiation of the MSC was examined by adipogenic and osteogenic induction. RESULTS The percentage of cells positive for NG2 was similar to the percentages of cells positive for CD73, CD105 and CD166 in all passages of BM samples. The mean fluorescent intensities of NG2 did not change with culture passage. The MSC was successfully differentiated into adipogenic and osteogenic lines. The cells showed no karyotypic abnormalities. CONCLUSIONS NG2 seems to be a promising marker for investigating the biology of MSC.

The apoptosis of blood polymorphonuclear leukocytes in sickle cell disease

The apoptosis of human polymorphonuclear leukocytes (PMNs) in patients with sickle cell disease (SCD) is not well understood. The goal of this study was to examine the apoptosis of PMNs in patients with SCD and in controls.

Effectiveness of Fludarabine- and Busulfan-Based Conditioning Regimens in Patients With Acute Myeloblastic Leukemia: 8-Year Experience in a Single Center

OBJECTIVE Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a curative treatment for acute myeloblastic leukemia (AML). Because the conditioning regimen of busulfan plus cyclophosphamide carries significant risks of toxicity, we evaluated the factors affecting survival after fludarabine replacement instead of cyclophosphamide. METHODS The study included 55 patients who underwent allo-HSCT for AML and received busulfan, fludarabine, and antithymocyte globulin (ATG). RESULTS Forty-eight patients received a myeloablative regimen; 7 patients received a reduced-intensity conditioning regimen. The neutrophil and platelet engraftment times were 12 days (range 9 to 20) and 12 days (range 7 to 19), respectively. Graft-vs-host disease (GvHD) developed in 10% and 50% of the patients, respectively. Seven patients received donor lymphocyte infusion. Of them, 5 patients developed grade I or II GvHD, one grade IV GvHD. The median follow-up period was 20.6 months. The predicted progression-free survival (PFS) at 1 and 3 years after transplantation was 78% and 74%, respectively. The overall survival (OS) at 1, 3, and 5 years was 76%, 74%, and 62%, respectively. Treatment-related mortality (infection in 1 patient, GvHD in 2 patients) occurred in 3 patients (5.5%). Multivariate analysis revealed that OS and PFS were not influenced by age, dose of busulfan or ATG, or presence of cytomegalovirus antigenemia. Acute GvHD and pretransplantation minimal residual disease positivity negatively affected the transplant outcome. The presence of active disease at the time of transplantation was found as an independent risk factor for AML. CONCLUSIONS Busulfan- and fludarabine-based conditioning regimens are effective for AML, and have acceptable toxicity, morbidity, and mortality.

Isolation and Identification of Mesenchymal Stem Cells

Adult bone marrow is a large organ composed of hematopoietic cells and stromal support cells. Mesenchymal stem cells (MSCs) are stromal stem cells of the bone marrow and the most preferred organ for isolation and proliferation of MSCs is the bone marrow. MSCs grown in culture with appropriate cytokine support are able to differentiate into various tissues such as bone, cartilage and adipose tissue. Clinical use of mesenchymal stem cells has been increasing as they inhibit T lymphocyte proliferation in mixed lymphocyte cultures in vitro and suppress the immune system through numerous soluble factors they release. Identification of these cells and accurate determination of their phenotypic properties will contribute to the understanding of their biological behaviors and increase reliability in clinical and experimental practices.

A detachment technique based on the thermophysiologic responses of cultured mesenchymal cells exposed to cold

Trypsinization has generally been used as a technique to detach adherent mesenchymal stromal cells (MSC). However, this technique involves chemical manipulation. This study was designed to identify whether detachment of MSC can be induced by cold without using trypsin. MSC isolated from bone marrow were detached via trypsin or exposed to -20 degrees C for 1, 5 or 10 min at all passages. Compared with trypsinization, exposing MSC to -20 degrees C for 10 min resulted in a significant decrease in MSC number and viability. In conclusion, although detachment of adhered MSC on culture dishes via exposure to cold may allow structurally and functionally intact detached cells, the technique requires improvement of the thermotolerance of MSC.

Effects of two doses of anti-T lymphocyte globulin-Fresenius given after full-match sibling stem cell transplantation in acute myeloblastic leukemia patients who underwent myeloablative fludarabine/busulfan conditioning

OBJECTIVE/BACKGROUND Anti-T lymphocyte globulin Fresenius (rATG-F; ATG-Fresenius) and antithymocyte globulin (thymoglobulin), which are included in transplant protocols, are used to reduce the risk of chronic graft-versus-host disease (cGVHD) or suppress allograft rejection. Available clinical studies have been conducted in heterogenous patient populations and with different administration protocols including stem cell sources. Additionally, the pharmacokinetics of ATG is variable, and the clinically effective dose of rATG-F, in particular, is not exactly known. The aim of the study was to investigate the clinical outcomes of acute myeloid leukemia (AML) patients who underwent hemopoietic peripheral stem cell transplantation from full-matched sibling donors and given two different doses of r-ATG-F. METHODS This was a single-center, retrospective chart review conducted between July 2005 and July 2016. Sixty-nine consecutive AML patients who underwent transplant with fludarabine- and busulfan-based conditioning were included in the study. Patients in Group 1 received 15 mg/kg body weight rATG-F to 2013 (n = 46), and Group 2 received 30 mg/kg of rATG-F dose begining in 2013 to reduce to cGVHD (n = 23). Cyclosporine and methotrexate were used to treat acute GVHD (aGVHD) prophylaxis. Outcome parameters were compared between the groups. RESULTS Although the recommended dose r-ATG-F had led to a decrease in the cumulative incidence of cGVHD (27 [58.7%] vs. 8 [34.8%]; p = .03), it also increased the infection rate at 1 year (3 [6.5%] vs. 4 [17.4%]; p = .02). The two groups were similar in terms of engraftment time, aGVHD, relapse, nonrelapse mortality, and rATG-F-related toxicity. A Cox regression model revealed that aGVHD III-IV was associated with increased nonrelapse mortality at 1 year (hazard ratio = 18.2; 95% confidence interval, 1.667-199.255; p = <.02). No patients developed rATG-F-related severe adverse events (Common Terminology Criteria grade 4 or 5). CONCLUSION Dose difference of rATG-F did not influence survival parameters; however, increasing the dose to 30 mg/kg seems to be effective for reducing cGVHD with an increase in infection rate requiring close monitoring of infections in AML patients who received myeloablative fludarabine/busulfan conditioning.

Implementation of ISBT 128 Compatible Medical Record System to Facilitate Traceability of Stem Cell Products.

Figure 1. Bar code denotes donation identification number (upper left), blood group (upper right), collection (or production) date and time (middle), product code (lower left), and expiration date and time (lower right). The biohazard mark was placed correctly on the labels of products that were detected to pose infection risks. Implementation of an ISBT 128-Compatible Medical Record System to Facilitate Traceability of Stem Cell Products Kök Hücre Ürünlerinin İzlenebilirliğini Kolaylaştırmak için ISBT 128 Uyumlu Tıbbi Kayıt Sisteminin Uygulanması