Bela Balint

Autologous bone marrow-derived progenitor cell transplantation for myocardial regeneration after acute infarction.

BACKGROUND Experimental and first clinical studies suggest that the transplantation of bone marrow derived, or circulating blood progenitor cells, may beneficially affect postinfarction remodelling processes after acute myocardial infarction. AIM This pilot trial reports investigation of safety and feasibility of autologous bone marrow-derived progenitor cell therapy for faster regeneration of the myocardium after infarction. METHODS AND RESULTS Four male patients (age range 47-68 years) with the first extensive anterior, ST elevation, acute myocardial infarction (AMI), were treated by primary angioplasty. Bone marrow mononuclear cells were administered by intracoronary infusion 3-5 days after the infarction. Bone marrow was harvested by multiple aspirations from posterior cristae iliacae under general anesthesia, and under aseptic conditions. After that, cells were filtered through stainless steel mesh, centrifuged and resuspended in serum-free culture medium, and 3 hours later infused through the catheter into the infarct-related artery in 8 equal boluses of 20 ml. Myocardial viability in the infarcted area was confirmed by dobutamine stress echocardiography testing and single-photon emission computed tomography (SPECT) 10-14 days after infarction. One patient had early stent thrombosis immediately before cell transplantation, and was treated successfully with second angioplasty. Single average ECG revealed one positive finding at discharge, and 24-hour Holter ECG showed only isolated ventricular ectopic beats during the follow-up period. Early findings in two patients showed significant improvement of left ventricular systolic function 3 months after the infarction. There were no major cardiac events after the transplantation during further follow-up period (30-120 days after infarction). Control SPECT for the detection of ischemia showed significant improvement in myocardial perfusion in two patients 4 months after the infarction. Echocardiographic assessment in these two patients also showed significant improvement of systolic function three months after the infarction. CONCLUSION Preliminary results of the study showed that the transplantation of bone marrow-derived progenitor cells into the infarcted area was safe, and feasible, and might improve myocardial function. Further follow-up will show if this treatment is effective in preventing negative remodeling of the left ventricle and reveal potential late adverse events (arrhythmogenicity and propensity for restenosis).

Loxoribine, a selective Toll-like receptor 7 agonist, induces maturation of human monocyte-derived dendritic cells and stimulates their Th-1- and Th-17-polarizing capability.

Recently, a guanosine analog, 7-allyl-7,8-dihydro-8-oxo-guanosine (loxoribine), has been identified as a selective Toll-like receptor (TLR)7 agonist. Bearing in mind the controversy regarding the expression of TLR7 by human myeloid dendritic cells (DCs) and its significance for functions of these cells, the goal of this study was to investigate the effect of loxoribine on differentiation, maturation and functions of human monocyte-derived (Mo)DCs. Immature MoDCs were obtained by cultivation of monocytes for 6 days with recombinant granulocyte macrophage-colony stimulating factor (GM-CSF) and interleukin (IL)-4. These cells were stimulated with loxoribine (250 μM) for an additional 48 h. Phenotypic properties of MoDCs were determined by flow cytometry, cytokine production was assayed by ELISA, whereas their allostimulatory capability was tested using a mixed leukocyte reaction. We showed that loxoribine up-regulated the expression of TLR7, CD40, CD54, CD80, CD83 and CCR7 and stimulated the production of IL-12, IL-23, IL-27 and IL-10 by MoDCs, whereas the level of interferon (IFN)-β was not modulated. Allogeneic CD4(+)T cells in co-culture with loxoribine-treated MoDCs proliferated more strongly, at lower DC/CD4(+)T-cell ratio (1:80), and secreted significantly higher levels of IL-17 and IFN-γ compared to the cultures with control MoDCs. The stimulatory effect of loxoribine on T helper (Th)1 polarization capability of MoDCs was further potentiated by ligation of CD40. In conclusion, our results show that loxoribine stimulated differentiation, maturation, allostimulatory as well as Th1 and Th17 polarization capability of human MoDCs and suggests that these effects might be associated with up-regulation of TLR7 expression, but not increased IFN-β production.

Differences in T-helper polarizing capability between human monocyte-derived dendritic cells and monocyte-derived Langerhans'-like cells

Langerhans’ cells (LCs) represent a specific subset of dendritic cells (DCs) which are important for detecting and processing pathogens that penetrate the skin and epithelial barriers. The aim of our study was to explain what makes their in vitro counterparts – monocyte‐derived Langerhans’‐like cells (MoLCs) – unique compared with monocyte‐derived dendritic cells (MoDCs). Immature MoDCs were generated by incubating peripheral blood monocytes with granulocyte–macrophage colony‐stimulating factor (GM‐CSF) and interleukin (IL)‐4. The addition of transforming growth factor‐β (TGF‐β) to this cytokine cocktail resulted in the generation of MoLCs. MoLCs showed a lower expression of CD83, CD86, HLA‐DR and CCR7 compared with MoDCs, regardless of their maturational status. Both immature and mature MoLCs secreted higher quantities of IL‐23 compared with MoDCs and this finding correlated with a higher secretion of IL‐17 in co‐culture of MoLCs with allogeneic CD4+ T cells. Mature MoLCs, which produced higher levels of IL‐12 and lower levels of IL‐10 compared with mature MoDCs, were more potent at inducing interferon‐γ (IFN‐γ) production by CD4+ T cells in the co‐culture system. In conclusion, the finding that mature MoLCs stimulate stronger T‐helper 1 and T‐helper 17 immune responses than mature MoDCs, makes them better candidates for use in the preparation of anti‐tumour DC vaccines.

Comparative effects of aspirin and NO-releasing aspirins on differentiation, maturation and function of human monocyte-derived dendritic cells in vitro.

Acetylsalicilyc acid (aspirin, ASA) is a well known anti-inflammatory drug with immunomodulatory properties. NO-releasing aspirins (NO-ASA) are new compounds with anti-inflammatory properties. We studied the effects of ASA and two NO-ASA (NCX 4016 and NCX 4040) on human monocyte-derived dendritic cells (MoDC). Immature MoDC were generated in vitro from monocytes in the presence of recombinant human granulocyte macrophage-colony stimulating factor (GM-CSF) and interleukin (IL)-4. Mature MoDC were obtained by adding lipopolysaccharide (LPS) in cultures of immature MoDC. As we found that ASA at 4-8 mM, NCX 4016 at 400-800 microM and NCX 4040 at 4-8 microM stimulated apoptosis of monocytes and immature MoDC, sub-apoptotic concentrations of ASA (2 mM), NCX 4016 (200 microM) and NCX 4040 (2 microM) were used in experiments. Examined substances were added at the beginning of MoDC cultivation. MoDC differentiated in the presence of examined compounds had lower expression of HLA-DR, CD80, CD40 and CD54, decreased allostimulatory activity and lower production of IL-12 p40. ASA and NCX 4016 decreased production of IL-10, whereas NCX 4040 had the opposite effect. ASA inhibited the expression of CD1a and prevented downregulation of CD14, NCX 4016 stimulated the differentiation of CD1a+CD14+ and CD1a(-)CD14+ cells, whereas NCX 4040 decreased the proportion of CD1a+CD14(-) and increased the frequency of CD1a+CD14+ cells, compared to control. Maturation, both in ASA and NO-ASA treated MoDC was characterized by decreased allostimulatory activity, lower expression of CD83, HLA-DR, costimulatory molecules and CD54 and decreased production of IL-10 and IL-12 p40. In conclusion, we confirmed that ASA impairs differentiation, maturation and function of MoDC and found that NCX 4016 and NCX 4040 exerted similar, but not identical effects at about 10- and 1000-fold lower concentrations, respectively, compared to ASA.

Stem cells in the arrangement of bone marrow repopulation and regenerative medicine.

Hematopoiesis is a permanent and complex event in which a spectrum of different mature blood cells from a small population of toti/pluri/multipotent stem cells (SCs) are produced through a variety of proliferative and differentiative processes. Hematopoietic SCs are defined as the cells with extensive self–renewal and proliferative potential, together with their ability to differentiate into all blood–cell lineages. Many studies have demonstrated that a multifactorious network of interactive cytokines and other blood–derived mediators regulate the survival, maturation, and proliferation of SCs .

Novel insights into the polycythemia-paraganglioma-somatostatinoma syndrome

Worldwide, the syndromes of paraganglioma (PGL), somatostatinoma (SOM) and early childhood polycythemia are described in only a few patients with somatic mutations in the hypoxia-inducible factor 2 alpha (HIF2A). This study provides detailed information about the clinical aspects and course of 7 patients with this syndrome and brings into perspective these experiences with the pertinent literature. Six females and one male presented at a median age of 28 years (range 11-46). Two were found to have HIF2A somatic mosaicism. No relatives were affected. All patients were diagnosed with polycythemia before age 8 and before PGL/SOM developed. PGLs were found at a median age of 17 years (range 8-38) and SOMs at 29 years (range 22-38). PGLs were multiple, recurrent and metastatic in 100, 100 and 29% of all cases, and SOMs in 40, 40 and 60%, respectively. All PGLs were primarily norepinephrine-producing. All patients had abnormal ophthalmologic findings and those with SOMs had gallbladder disease. Computed tomography (CT) and magnetic resonance imaging revealed cystic lesions at multiple sites and hemangiomas in 4 patients (57%), previously thought to be pathognomonic for von Hippel-Lindau disease. The most accurate radiopharmaceutical to detect PGL appeared to be [18F]-fluorodihydroxyphenylalanine ([18F]-FDOPA). Therefore, [18F]-FDOPA PET/CT, not [68Ga]-(DOTA)-[Tyr3]-octreotate ([68Ga]-DOTATATE) PET/CT is recommended for tumor localization and aftercare in this syndrome. The long-term prognosis of the syndrome is unknown. However, to date no deaths occurred after 6 years follow-up. Physicians should be aware of this unique syndrome and its diagnostic and therapeutic challenges.

Controlled‐rate versus uncontrolled‐rate freezing as predictors for platelet cryopreservation efficacy

BACKGROUND:  Cryobiologic variables responsible for cell injuries and freezing techniques applicable in medical cryopractice should be revised and/or reengineered for minimizing cryoinjuries and maximizing cell recovery. In this study, the efficacy of different cryopreservation protocols based on platelet (PLT) recovery was evaluated.

Mirasol PRT system inactivation efficacy evaluated in platelet concentrates by bacteria-contamination model.

BACKGROUND/AIM Bacterial contamination of blood components, primarily platelet concentrates (PCs), has been identified as one of the most frequent infectious complications in transfusion practice. PC units have a high risk for bacterial growth/multiplication due to their storage at ambient temperature (20 +/- 2 degrees C). Consequences of blood contamination could be effectively prevented or reduced by pathogen inactivation systems. The aim of this study was to determine the Mirasol pathogen reduction technology (PRT) system efficacy in PCs using an artificial bacteria-contamination model. METHODS According to the ABO blood groups, PC units (n = 216) were pooled into 54 pools (PC-Ps). PC-Ps were divided into three equal groups, with 18 units in each, designed for an artificial bacteria-contamination. Briefly, PC-Ps were contaminated by Staphylococcus epidermidis, Staphylococcus aureus or Escherichia coli in concentrations 10(2) to 10(7) colony forming units (CFU) per unit. Afterward, PC-Ps were underwent to inactivation by Mirasol PRT system, using UV (lambda = 265-370 nm) activated riboflavin (RB). All PC-Ps were assayed by BacT/Alert Microbial Detection System for CFU quantification before and after the Mirasol treatment. Samples from non-inactivated PC-P units were tested after preparation and immediately following bacterial contamination. Samples from Mirasol treated units were quantified for CFUs one hour, 3 days and 5 days after inactivation. Results. A complete inactivation of all bacteria species was obtained at CFU concentrations of 10(2) and 10(3) per PC-P unit through storage/investigation period. The most effective inactivation (10(5) CFU per PC-P unit) was obtained in Escherichia coli setting. Contrary, inactivation of all the three tested bacteria species was unworkable in concentrations of > or = 10(6) CFU per PC-P unit. CONCLUSION Efficient inactivation of investigated bacteria types with a significant CFU depletion in PC-P units was obtained--3 Log for all three tested species, and 5 Log for Escherichia coli. The safety of blood component therapy, primarily the clinical use of PCs can be improved using the Mirasol PRT system.

Increased angiogenesis-associated poor outcome in acute lymphoblastic leukemia: a single center study.

Angiogenesis in solid tumors is important for tumor growth, invasion, and metastasis. However, angiogenesis plays also an important role in hematological malignancies. We have analyzed the expression of vascular endothelial growth factor (VEGF) in the leukemic blast cells and microvessel density (MVD) in the bone marrow biopsy samples of the patients with acute lymphoblastic leukemia (ALL). Bone marrow MVD of the patients with ALL was significantly higher compared with normal controls and complete remission (P<0.001), but slightly lower than in patients with relapsed ALL (P>0.05). The bone marrow blast VEGF expression was significantly higher in newly diagnosed ALL patients, with predominant strong VEGF expression as compared with complete remission patients (who had negative or weak VEGF expression) (P<0.05), whereas initial values were slightly lower than in relapsed patients. There was a strong positive correlation between VEGF expression and MVD at presentation of ALL. Stronger expression of VEGF on blast cells indicates shorter overall survival in ALL. Furthermore, initial values of MVD had positive correlation with overall survival and leukemia-free survival (P=0.024 and P=0.017, respectively). Our data suggest that increased angiogenesis (confirmed by immunohistochemical expression of VEGF in leukemic blasts), and MVD may play an important role in the pathophysiology of ALL with prognostic implications. Thus, targeting VEGF pathway may bring the new approach for ALL treatment—using antiangiogenic drugs and tyrosine kinase inhibitors in combination with standard chemotherapy regimens.

Autologous transplant in the treatment of severe aplastic anemia – A case report

The initial use of immunosuppressive therapy (IST) in severe aplastic anemia (sAA) or reapplication of IST-centered methods following disease relapse is successful only in well-selected patients. The potential treatment by autologous stem cell (SC) transplant in sAA is still an innovative/pioneering therapeutic approach. To our best knowledge, this is the second published case of autologous SC transplant in sAA. The aim of this work was to optimize mobilization and timing for SC harvesting - using our own controlled-rate cryopreservation - with higher CD34(+)/CD90(+) subset yield and recovery in order to obtain complete and long-term hematopoietic reconstitution following autologous SC transplant. We report a 35 year-old sAA male patient who initially underwent IST using rabbit ATG and Cyclosporine A (CsA). He was supportive transfusion dependent for the whole period of IST-phase. After the second IST-cycle, polymorphonuclear (PMN) cell count increase (>2.0 × 10(9)/L) was observed, when SC mobilization, two large volume leukapheresis procedures and following autologous transplant were performed. The yields of harvested CD34(+) and CD34(+)/CD90(+) cells were 5.75 × 10(6)/kgbm and 1.7 × 10(6)/kgbm, respectively. The quantity of applied CD34(+) and CD34(+)/CD90(+) cells in autologous SC transplant were 5.45 × 10(6)/kgbm (7-AAD(CD34)(+)(viability)=95.42%) and 1.63 × 10(6)/kgbm (7-AAD(CD34)(+)(/CD90)(+)(viability)=95.42%), respectively. Hematopoietic reconstitution registered due to second month after autologous SC transplant and he is 24 months in complete medullar, hematological and clinical remission, with normal cytogenetic status - applying only continuous CsA therapy. The results obtained strongly confirm that in sAA, with no allogeneic SC donor, autologous transplant can result in a successful clinical outcome. We suggest that CD34(+)/CD90(+) subset count in peripheral blood and/or cell-harvest could be more valuable predictive factor than total CD34(+) quantity of optimized collection-timing and superior treatment efficacy of autologous SC transplant in sAA.