A Validation Study on Immunophenotypic Differences in T-lymphocyte Chromosomal Radiosensitivity between Newborns and Adults in South Africa

Children have an increased risk of developing radiation-induced secondary malignancies compared to adults, due to their high radiosensitivity and longer life expectancy. In contrast to the epidemiological evidence, there is only a handful of radiobiology studies which investigate the difference in radiosensitivity between children and adults at a cellular level. In this study, the previous results on the potential age dependency in chromosomal radiosensitivity were validated again by means of the cytokinesis-block micronucleus (CBMN) assay in T-lymphocytes isolated from the umbilical cord and adult peripheral blood of a South African population. The isolated cells were irradiated with 60Co γ-rays at doses ranging from 0.5 Gy to 4 Gy. Increased radiosensitivities of 34%, 42%, 29%, 26% and 16% were observed for newborns compared to adults at 0.5, 1, 2, 3 and 4 Gy, respectively. An immunophenotypic evaluation with flow cytometry revealed a significant change in the fraction of naïve (CD45RA+) T-lymphocytes in CD4+ and CD8+ T-lymphocytes with age. Newborns co-expressed an average of 91.05% CD45RA+ (range: 80.80–98.40%) of their CD4+ cells, while this fraction decreased to an average of 39.08% (range: 12.70–58.90%) for adults. Similar observations were made for CD8+ cells. This agrees with previous published results that the observed differences in chromosomal radiosensitivity between newborn and adult T-lymphocytes could potentially be linked to their immunophenotypic profiles.

Cord Blood Derived Endothelial Progenitor Cells Are More Immunosuppressive and Immunomodulator than Their Adult Peripheral Blood Counterparts

Endothelial progenitor cells (EPCs) are immature endothelial cells (ECs) present in blood circulation that are involved in neo-vascularization and correction of ischemic sites. Several cardiovascular disorders are correlated with patients inefficient and impaired EPCs, therefore, cell therapy using functional allogenic EPCs are considered as only alternative. Many studies show that cord blood (CB) yields much more EPCs than adult peripheral blood (APB), and these CB-EPCs are also more active. However, due to the reaction of host immune response to allogenic cells which usually lead to their rejection, we have investigated the exact impact of EPCs on immune cells. The pro-angiogenic and regenerative properties of EPCs have been already reported. However, little is known about their immunological features. Using different in-vitro combinations, we performed co-cultures of EPCs and T cells to investigate the interaction of EPCs and immune system. We demonstrated that both CB-EPCs APB-EPCs are able to suppress total PBMCs and among them T cell proliferation. In addition, our results reveal a more accentuated immunosuppressive and immunomodulatory function of CB-EPCs in comparison to APB-EPCs. This finding proves that CB-EPCs are more proper to cell therapy applications. Displaying both angiogenic and immunosuppressive properties make them the ideal choice for pathological conditions in which both functions are critical.

Comparative Preliminary Analysis of Umbilical Cord Blood-, Healthy Adult Peripheral Blood- and Myocardial Infarct Peripheral Blood-Derived Endothelial Progenitor Cells

BACKGROUND: Cardiovascular disease is a leading cause of death globally with the 287,000 deaths per years, characterized by declining of heart function caused by the reduction of heart capacity and lead to heart failure. Cell therapy using endothelial progenitor cells (EPCs) has a big potential for cardiovascular regeneration. EPCs are cells that have ability to differentiate into endothelial cells that can be mobilized and integrated into the defected blood vessel by angiogenesis. AIM: We aimed to seek the superior EPCs derived from MNCs for functional improvement of advanced heart failure patient by cell therapy using EPCs. MATERIALS AND METHODS: We did preliminary analysis to compare umbilical cord blood (UCB), healthy adult peripheral blood (PB)-, and myocardial infarct PB-derived EPCs characteristic and surface phenotypes. Different sources of each EPCs mononuclear cells were characterized by the expression of endothelial (cluster of differentiation [CD] 31, acethylated low-density lipoprotein, and von Willebrand) and hematopoietic stem cell (CD45, CD34, and CD133) surface markers with flow cytometry. RESULTS: In this study, EPCs and the conditioned medium (CM) have been produced and characterized in laboratory scale by comparing several sources of EPCs for instance UCB, PB from healthy people, and patients with myocardial infarction. We have shown that EPC characterizations from each group were not significantly different, but vascular endothelial growth factor and hepatocyte growth factor in UBC-derived CM-EPCs were higher than in PB. CONCLUSION: In conclusion, the UBC-derived EPCs might have a better potential for cardiovascular regeneration.

Preliminary Report of In vitro and In vivo Effectiveness of Dornase Alfa on SARS-CoV-2 Infection (Preprint)

UNSTRUCTURED Dornase alfa, the recombinant form of the human DNase I enzyme, breaks down neutrophil extracellular traps (NET) that include a vast amount of DNA fragments, histones, microbicidal proteins and oxidant enzymes released from necrotic neutrophils in the highly viscous mucus of cystic fibrosis patients. Dornase alfa has been used for decades in patients with cystic fibrosis to reduce the viscoelasticity of respiratory tract secretions, to decrease the severity of respiratory tract infections, and to improve lung function. Previous studies have linked abnormal NET formations to lung diseases, especially to acute respiratory distress syndrome (ARDS). Coronavirus disease 2019 (COVID-19) pandemic affected more than two million people over the world, resulting in unprecedented health, social and economic crises. The COVID-19, viral pneumonia that progresses to ARDS and even multiple organ failure, is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). High blood neutrophil levels are an early indicator of SARS-CoV-2 infection and predict severe respiratory diseases. A similar mucus structure is detected in COVID-19 patients due to the accumulation of excessive NET in the lungs. Here, we show our preliminary results with dornase alfa that may have an in-vitro anti-viral effect against SARS-CoV-2 infection in a bovine kidney cell line, MDBK without drug toxicity on healthy adult peripheral blood mononuclear cells. In this preliminary study, we also showed that dornase alfa can promote clearance of NET formation in both an in-vitro and three COVID-19 cases who showed clinical improvement in radiological analysis (2-of-3 cases), oxygen saturation (SpO2), respiratory rate, disappearing of dyspnea and coughing.

Preliminary Report of In vitro and In vivo Effectiveness of Dornase Alfa on SARS-CoV-2 Infection (Preprint)

UNSTRUCTURED Dornase alfa, the recombinant form of the human DNase I enzyme, breaks down neutrophil extracellular traps (NET) that include a vast amount of DNA fragments, histones, microbicidal proteins and oxidant enzymes released from necrotic neutrophils in the highly viscous mucus of cystic fibrosis patients. Dornase alfa has been used for decades in patients with cystic fibrosis to reduce the viscoelasticity of respiratory tract secretions, to decrease the severity of respiratory tract infections, and to improve lung function. Previous studies have linked abnormal NET formations to lung diseases, especially to acute respiratory distress syndrome (ARDS). Coronavirus disease 2019 (COVID-19) pandemic affected more than two million people over the world, resulting in unprecedented health, social and economic crises. The COVID-19, viral pneumonia that progresses to ARDS and even multiple organ failure, is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). High blood neutrophil levels are an early indicator of SARS-CoV-2 infection and predict severe respiratory diseases. A similar mucus structure is detected in COVID-19 patients due to the accumulation of excessive NET in the lungs. Here, we show our preliminary results with dornase alfa that may have an in-vitro anti-viral effect against SARS-CoV-2 infection in a bovine kidney cell line, MDBK without drug toxicity on healthy adult peripheral blood mononuclear cells. In this preliminary study, we also showed that dornase alfa can promote clearance of NET formation in both an in-vitro and three COVID-19 cases who showed clinical improvement in radiological analysis (2-of-3 cases), oxygen saturation (SpO2), respiratory rate, disappearing of dyspnea and coughing.