Molecular dioxygen, O2, is an important element in cellular microenvironment in vivo, and often overlooked in standard in vitro and ex vivo cell culture systems. Molecular oxygen is the ultimate electron acceptor in oxidative cellular respiration, and also a signal that regulates cell fate through concentration gradients. Recent advances in physiology of oxygen and adult stem cell research have shown that apart from being important for oxidative phosphorylation, thus energy metabolism, oxygen is also important as a signaling molecule and an integral part of stem cell niche. This review article covers the influence of physiologically relevant oxygen levels on adult stem cells through highlighting the research on the effect of oxygen concentration on hematopoietic stem cell maintenance, proliferation and differentiation. This is important particularly to understand the embryonic and adult stem cell biology and physiology. The new discoveries in this field will help to further improve current tissue engineering and clinical applications. In addition, understanding the relationship between oxygen and stemness is invaluable for the advanced treatments of neoplastic diseases. Authors believe that in future, active and programmed dynamic of oxygen levels will be routinely used for the programmed in vitro and ex-vivo expansion of different adult stem cell types and tissue regeneration purposes.
COBISS.SI-ID: 31964633
Background: The appropriate dose of compatible and viable hematopoietic progenitor cells (HPC) is crucial for successful engraftment of transplanted cells within patients. In the study we therefore checked the viability of HPC in thawed HPC grafts which were transplanted into haematology patients in one year. Methods: We acquired HPC by apheresis and froze them in a programmable freezer in autologous plasma with 10 % DMSO and stored them in liquid nitrogen vapour. We thawed the bags with HPC in a water bath at the patient's bedside and in the eluate residues from the bags after the addition of saline solution we determined the viability (7-AAD) of HPC (CD34 +) and lymphocytes by flow cytometry. Results: After the transplantation of HPC, the viability of HPC was 79.9 +- 12.4 % and of leukocytes 62.2 +- 12.2 % (paired t-test, P ( 0.001) in cell suspension residues (n = 88). The average viability of HPC in samples which were frozen immediately after collection (n = 58) was 79.9 +- 9.2 % and in samples frozen the next day after 18 hours in the fridge, the viability was 80.5 +- 11.3 % (n = 67). Storing samples overnight did not significantly affect the viability of cells in comparison with samples which were frozen immediately (t-test, P ) 0.5). Rinsing of HPC bags and storing cells after thawing in saline solution significantly (n = 7; paired t-test, P (0.01) increased the mortality of HPC, since the viability immediately after thawing was 84.1 +- 4.5 % and in samples diluted with saline solution 60.1 +- 15.7 %. Conclusions: In our laboratory, cca 20 % of HPC are lost during freezing and thawing of HPC grafts. Freezing HPC grafts 18 hours after cell collection does not affect the viability of thawed cells in comparison with grafts which are frozen immediately. Saline solution is not suitable for rinsing bags and storing HPC residuals after thawing HPC products.
COBISS.SI-ID: 32068057
Extracellular membrane vesicles are fragments shed from plasma membranes off all cell types that are undergoing apoptosis or are being subjected to various types of stimulation or stress. Even in the process of programmed cell death (apoptosis), cell fall apart of varying size vesicles. They expose phosphatidylserine (PS) on the outer leaflet of their membrane, and bear surface membrane antigens reflecting their cellular origin. Extracellular membrane vesicles have been isolated from many types of biological fluids, including serum, cerebrospinal fluid, urine, saliva, tears and conditioned culture medium. Flow cytometry is one of the many different methodological approaches that have been used to analyze EMVs. The method attempts to characterize the EMVs cellular origin, size, population, number, and structure. EMVs are present and accumulate in blood products (erythrocytes, platelets) as well as in fresh frozen plasma during storage. The aim of this review is to highlight the importance of extracellular vesicles as a cell-to-cell communication system and the role in the pathogenesis of different diseases. Special emphasis will be given to the implication of extracellular membrane vesicles in blood products and their clinical relevance. Although our understanding of the role of EMVs in disease is far from comprehensive, they display promise as biomarkers for different diseases in the future and also as a marker of quality and safety in the quality control of blood products.
COBISS.SI-ID: 32458201
Stem cells, among other, are a possible participants in formation of cancer. Glioblastoma multiforme (GBM) is among the most aggressive cancers with a poor prognosis in spite of a plethora of established diagnostic and prognostic biomarkers and treatment modalities. Therefore, the current goal is the detection of novel biomarkers, possibly detectable in the blood of GBM patients that may enable an early diagnosis and are potential therapeutic targets, leading to more efficient interventions. Experimental Procedures: MicroRNA profiling of 734 human and human-associated viral miRNAs was performed on blood plasma samples from 16 healthy individuals and 16 patients with GBM, using the nCounter miRNA Expression Assay Kits. Results: We identified 19 miRNAs with significantly different plasma levels in GBM patients, compared to the healthy individuals group with the difference limited by a factor of 2. Additionally, 11 viral miRNAs were found differentially expressed in plasma of GBM patients and 24 miRNA levels significantly correlated with the patients’ survival. Moreover, the overlap between the group of candidate miRNAs for diagnostic biomarkers and the group of miRNAs associated with survival, consisted of ten miRNAs, showing both diagnostic and prognostic potential. Among them, hsa miR 592 and hsa miR 514a 3p have not been previously described in GBM and represent novel candidates for selective biomarkers. The possible signalling, induced by the revealed miRNAs is discussed, including those of viral origin, and in particular those related to the impaired immune response in the progression of GBM. Conclusion: The GBM burden is reflected in the alteration of the plasma miRNAs pattern, including viral miRNAs, representing the potential for future clinical application. Therefore proposed biomarker candidate miRNAs should be validated in a larger study of an independent cohort of patients.
COBISS.SI-ID: 3453007