Chu-Myong Seong

Unsorted human adipose tissue-derived stem cells promote angiogenesis and myogenesis in murine ischemic hindlimb model.

We examined the protective effect of unsorted human adipose tissue-derived stem cells (hADSCs) with a short-term culture in endothelial differentiation medium on tissue repair after ischemic injury. hADSCs were isolated from human subcutaneous adipose tissue and cultured in vitro in endothelial differentiation medium for 2wks before transplantation. Cultured hADSCs showed a typical mesenchymal stromal cell-like phenotype, positive for endothelial-specific markers including VE-cadherin, Flt-1, eNOS, and vWF but not CD31. Two hours after ligation of the femoral artery and vein, mice were injected with the unselected hADSCs locally near the surgery site and tested for tissue perfusion and repair. Tissue perfusion rates of the ischemic limbs were significantly higher in the group treated with hADSCs compared with those of the control mice as early as post-operative day 3 (median 195.3%/min; interquartile range, 82.0-321.1 vs. median 47.1%/min; interquartile range, 18.0-58.7; p=0.001 by Friedman two-way analysis). Subsequently, the mice treated with hADSC showed better prognosis at 4wks after surgery, and the histological analysis revealed increased vascular density and reduced muscle atrophy in the hADSC-transplanted limbs. Moreover, hADSC-treated muscle contained differentiated myocytes positive for human NF-κB and myogenin antigen. These results collectively indicate that unsorted hADSCs after a 2-wk-in vitro culture have a therapeutic potential in ischemic tissue injury via inducing both angiogenesis and myogenesis.

Early Imatinib Mesylate-Induced Hepatotoxicity in Chronic Myelogenous Leukaemia

Imatinib mesylate is the first molecule of targeted therapy in chronic myelogenous leukaemia inhibiting constitutively activated BCR-ABL kinase. There are no long-term follow-up studies of large sample sizes to assess the toxicity of the use of imatinib mesylate over 10 years. Several cases of hepatotoxicity, including fatal liver failure, have been associated with the long-term use of imatinib mesylate. We report here on a patient who experienced immediate dominant cholestatic damage of the liver and mild hepatocyte damage during imatinib mesylate therapy. This differs from most reports showing dominantly acute hepatitis with necrosis associated with the use of imatinib mesylate.

Distinct patterns of apoptosis in association with modulation of CD44 induced by thrombopoietin and granulocyte‐colony stimulating factor during ex vivo expansion of human cord blood CD34+ cells

The insufficient number of haemopoietic stem cells (HSCs) in cord blood (CB) is the major potential limitation to widespread use of CB for marrow replacement. Cytokine‐mediated ex vivo expansion has been proposed as a means of increasing the number of CB HSCs for transplantation. However, the biology of CB HSCs during cytokine‐mediated ex vivo expansion, such as apoptosis or expression of adhesion molecules, has not yet been elucidated. We have investigated the patterns of apoptosis and CD44 expression on human CB CD34+ cells during ex vivo expansion. CD34+ cells isolated from human CB were cultured in a stroma‐free liquid culture system with thrombopoietin (TPO), flt3‐ligand (FL), stem cell factor (SCF), and/or granulocyte‐colony stimulating factor (G‐CSF). During the culture, for up to 5 weeks, apoptosis was measured by staining with 7‐amino‐actinomycin D (7‐AAD) along with concurrent immunophenotyping of CD34 and CD44 with three‐colour flow cytometry. In the cultures with TPO, an apoptotic fraction with down‐regulated CD44 appeared from the fourth day up to the second week. G‐CSF also induced apoptosis but in a different manner; the apoptotic fraction without down‐regulation of CD44 appeared unremittingly for up to 5 weeks. FL did not induce apoptosis or down‐regulation of CD44. These findings show that apoptosis is indeed involved in the regulation of CB CD34+ cells in ex vivo expansion and the patterns of apoptosis are dependent on the type of cytokines used. The distinct patterns of apoptosis suggest different mechanisms of TPO and G‐CSF in inducing apoptosis, which still remains to be elucidated.

CD34, RAB20, PU.1 and GFI1 mRNA expression in myelodysplastic syndrome.

Myelodysplastic syndrome (MDS) with hypocellular bone marrow (BM) is often difficult to distinguish from aplastic anemia (AA). Furthermore, the diagnosis of MDS with low blast counts and normal karyotype may be problematic. These issues highlight the need for a reliable marker for the diagnosis of MDS. This study was conducted to determine if changes of mRNA expression in any of the four selected genes would be useful markers for differentiation of hypoplastic MDS from AA, and MDS from benign disease, as well as to investigate whether mRNA expressions differ between MDS risk subgroups. Thirty‐five patients diagnosed with MDS, 27 patients with AA and 17 patients with benign diseases were included. The CD34, RAB20, PU.1 and GFI1 mRNA levels were measured by real‐time RT‐PCR. The CD34 mRNA expressions in hypoplastic MDS were higher than those found in AA. PU.1 and GFI1 mRNA expressions were significantly lower in MDS with low blast counts and normal karyotype than those of benign disease. High‐risk MDS showed higher CD34 expressions than those of low‐risk MDS. This study suggests that measurement of CD34 and GFI1 mRNA expressions could be useful as a diagnostic and prognostic marker for MDS.

Bortezomib, thalidomide, dexamethasone induction therapy followed by melphalan, prednisolone, thalidomide consolidation therapy as a first line of treatment for patients with multiple myeloma who are non-transplant candidates: results of the Korean Multiple Myeloma Working Party (KMMWP).

Bortezomib (VELCADE®), thalidomide and dexamethasone (VTD), as well as melphalan, prednisolone, and thalidomide (MPT) therapy, are highly effective in patients with multiple myeloma. We evaluated the responses and survival times of 35 patients treated with VTD followed by MPT. All patients were newly diagnosed and non-transplantation candidates. Patients received six cycles of VTD, which were followed by eight cycles of MPT. Approximately 97% of patients exhibited early responses to therapy, as early as the second cycle of VTD. Thirty percent of the responses were high quality, which was defined as a complete response (CR), a near-CR or a very good partial response. High-risk patients were defined as patients with any of the following aberrations: del(13), t(4;14), or del(17p). The remaining patients were defined as standard risk. Eleven high-risk patients showed 100% response rates, including 91% high-quality responses. In contrast, 13 standard-risk patients exhibited 92% response rates, including 61% high-quality responses. The overall 2-year survival rates were 60% in high-risk patients and 85% in standard-risk patients, which was not significantly different. As a first-line therapy, VTD followed by MPT has the potential to provide high-quality responses with durable remission among elderly and high-risk patients (clinicaltrials.gov identifier: NCT00320476).

Characterization of phenotypically distinct B-cell subsets and receptor-stimulated mitogen-activated protein kinase activation in human cord blood B cells

Human cord blood (CB) is a valuable source of hematopoietic stem cells, but clinical reports have indicated slow recovery of B‐cell development and function after CB transplantation. To investigate the basis of these B‐cell defects in reconstitution, we characterized B cells purified from CB. We compared B‐cell receptor activation and B‐cell subsets in CB, bone marrow (BM), and peripheral blood (PB). We found that in CB B cells activation of extracellular signal‐regulated kinase (ERK) and p38 following ligation of CD40 but not of the B‐cell antigen receptor (BCR) was inefficient. The patterns of expression of CD5, CD34, and CD40 in the B‐cell population of CB were similar to those in PB rather than in BM. The B cells in CB contained an increased proportion of B cells expressing a high level of CD24 and a low proportion of B cells expressing CD27, pointing to the presence of circulating CD24high immature transitional and CD27− naive B cells. CD40‐mediated activation of ERK and p38 was also minimal in these B cells of CB. These findings may account for the functional defects of B cells in transplanted CB.

Topoisomerase II alpha and microtubule-associated protein-tau as a predictive marker in axillary lymph node positive breast cancer.

Aims and Background The aims of this study were to investigate the correlation between topoisomerase II alpha (TOP2A), microtubule-associated protein-tau (MAPtau) and other prognostic factors in breast cancer and to evaluate the predictive value of TOP2A and MAP-tau in breast cancer patients who received anthracycline and taxane-containing adjuvant chemotherapy. Methods and Study Design Seventy patients with axillary lymph node positive breast cancer who underwent curative surgery between January 2000 and December 2005 were evaluated retrospectively. The levels of protein expression of TOP2A and MAPtau were assessed using immunohistochemistry. Results Among the 70 patients, 43 (61.4%) showed TOP2A overexpression and 30 (42.9%) showed MAP-tau positivity. TOP2A overexpression was associated with p53 positivity and high histological grade. MAP-tau positivity was associated with a lower positive lymph node ratio, lower proliferative activity, and hormone receptor positivity. Based on the TOP2A and MAP-tau expression, there was no significant difference in disease-free survival in the breast cancer patients who received anthracycline and taxane-containing adjuvant chemotherapy. Conclusions We conclude that immunohistochemical analysis of TOP2A and MAPtau protein expression may not predict the benefits of adjuvant anthracycline and taxane chemotherapy in axillary node positive breast cancer.

Various patterns of IgH deletion identified by FISH using combined IgH and IgH/CCND1 probes in multiple myeloma and chronic lymphocytic leukemia

Introduction:  Interphase fluorescence in situ hybridization (FISH) can identify submicroscopic deletions adjacent to the breakpoints of rearrangements undetected by conventional cytogenetics. In this study, the characteristics and frequency of the IgH deletion identified by interphase FISH were investigated in patients with multiple myeloma (MM) and chronic lymphocytic leukemia (CLL).

A new HLA-A*33 variant, HLA-A*3314, identified in a Korean individual.

The sequence of human leukocyte antigen (HLA)-A*3314 is identical to that of HLA-A*330301 except for a single-nucleotide substitution at codon 49 (GCG-->GGG) resulting in an amino acid change from Ala to Gly.

A prospective randomized study on the mobilization of CD34 + cells comparing continuous intravenous vs subcutaneous administration of rhG-CSF in normal donors

Summary:The efficacy of mobilizing peripheral blood progenitor cells (PBPC) with continuous intravenous (c.i.v.) administration of rhG-CSF was randomly compared to subcutaneous (s.c.) administration, in 15 normal donors in each arm of the study for 6 days. The percentage and absolute numbers of CD34+ cells in the c.i.v. and s.c. groups increased maximally at day 3 and 5, respectively, when compared with the steady-state (day 0) level. Peak CD34+ cell levels were achieved on day 3 in the c.i.v. group, with more rapid results than in the s.c. group (49.3/μl vs 35.9/μl, P=0.043). Plasma rhG-CSF levels declined progressively during mobilization in each group as the WBC increased. The serum level of rhG-CSF did not correlate with CD34+ cell counts in the peripheral blood. Toxicity profiles in the c.i.v. and s.c. groups were similar. Each regimen was effective in successfully mobilizing the target CD34 cell number.