Filipe Sehn

Effects Of Hypoxia in Long-Term In Vitro Expansion of Human Bone Marrow Derived Mesenchymal Stem Cells: EFFECTS OF HYPOXIA ON hMSC

Mesenchymal stem cells (MSC) are considered multipotent stromal, non‐hematopoietic cells with properties of self‐renovation and differentiation. Optimal conditions for culture of MSC have been under investigation. The oxygen tension used for cultivation has been studied and appears to play an important role in biological behavior of mesenchymal cells. The aim is characterize MSC in hypoxia and normoxia conditions comparing their morphological and functional characteristics. Bone marrow‐derived mesenchymal stem cells obtained from 15 healthy donors and cultured. MSC obtained from each donor were separated into two cultivation conditions normoxia (21% O2) and hypoxia (three donors at 1%, three donors at 2%, five donors at 3%, and four donors at 4% O2) up to second passage. MSC were evaluated for proliferation, differentiation, immunophenotyping, size and cell complexity, oxidative stress, mitochondrial activity, and autophagy. Culture conditions applied did not seem to affect immunophenotypic features and cellular plasticity. However, cells subjected to hypoxia showed smaller size and greater cellular complexity, besides lower proliferation (P < 0.002). Furthermore, cells cultured in low O2 tension had lower mitochondrial activity (P < 0.03) and a reduced tendency to autophagy, although oxidative stress did not vary among groups (P < 0.39). Oxygen tension seems to be a key regulator of cellular adaptation in vitro, and metabolic effects underlying this variable remain undescribed. Heterogeneity or even lack of results on the impact of oxygen concentration used for expanding MSC highlights the need for further research, in order to optimize conditions of cultivation and expansion and achieve greater safety and therapeutic efficacy. J. Cell. Biochem. 118: 3072–3079, 2017.

Donor characteristics and hematopoietic stem cell transplantation outcome: experience of a single center in Southern Brazil

Background Hematopoietic stem cell transplantation is a curative treatment for many patients with hematological disorders. Donor–recipient genetic disparity, especially involving the human leukocyte antigen system is a critical factor for transplant outcome. Objective To evaluate retrospectively donor characteristics and correlations with the occurrence of acute and chronic graft-versus-host disease, disease-free survival and overall survival in a Brazilian population submitted to allogeneic hematopoietic stem cell transplantation between 1994 and 2012 in a single center. Results Three hundred and forty-seven consecutive transplantations were included. Related transplants (81.2%) were significantly more common than unrelated transplants (18.7%); donor and recipient median ages were 34 (range: 1–61) and 33 (range: 3–65) years respectively with donor HLAs being matched for 333 (95.9%) patients. Donor gender, cytomegalovirus status and ABO incompatibility did not influence the five-year overall survival. In univariate analyses, overall survival was negatively influenced by the presence of acute graft-versus-host disease (33% vs. 47%, respectively; p-value = 0.04), unrelated transplant (41.5% vs. 50.9%, respectively; p-value = 0.045) and donors aged over 40 years (41% vs. 52%, respectively; p-value = 0.03). Older donors were associated with a higher rate of acute (52% vs. 65.8%; p-value = 0.03) and chronic graft-versus-host disease (60% vs. 43%, respectively; p-value = 0.015). In multivariate analyses, acute graft-versus-host disease [relative risk (RR): 1.8; 95% confidence interval (CI): 1.1–29; p-value = 0.008] and older donors (RR: 1.6; 95% CI 1.11–2.24; p-value = 0.013) were associated with higher transplant-related mortality. Conclusions In transplant patients, to have a donor older than 40 years of age seems to significantly increase the incidence of acute and chronic graft-versus-host disease and transplant-related mortality with no impact on disease-free survival and overall survival. In spite of the rather small cohort of patients, these findings are similar to what is described in the literature suggesting that a younger donor should be chosen whenever possible.

Mesenchymal stem cells for Glenoid chondral lesions: An exceptional use

Background: Damage to the articular cartilage is usually caused by accidental or athletic injuries or trauma often progressing to more severe joint diseases, such as osteoarthritis, subchondral bone necrosis, and arthritis. It is estimated that 15% of the world’s adult population is affected by joint diseases. The long-term success of cartilage repair depends on the development of alternative regenerative approaches. In recent years, the use of stem cells for the treatment of degenerative diseases has been widely explored. Here we report a case of exceptional use of autologous bone marrow mesenchymal stem cells expanded in medium supplemented with autologous platelet lysate in a patient with glenoid chondral erosion. Methods: A 17-year-old patient was diagnosed as having chondral erosion of the center of the labrum in the right shoulder, with symptoms of pain and insecurity in the right upper limb. Thirty days before arthroscopy, autologous platelets and stem cells were obtaind from apheresis and BM aspiration, respectively. Arthroscopy was then performed with the patient in the lateral decubitus position with arm abducted to 45° under manual traction. Microfracture was performed in the central region defect, and MSC intra-articular injection was performe after extensive washing with sterile saline. Discussion: No adverse reactions were observed. Two years after arthroscopy, there were no sign of lesion in cartilage, rotator cuff or biceps tendon were observed in magnetic resonance imaging. Further studies are needed to validate the clinical efficacy and safety of MSC injection for glenoid chondral defect treatment. Trial registration: The procedure was approved by Hospital de Clínicas de Porto Alegre Research Ethics Committee protocol number 14-0545. Correspondence to: Lucia Silla, Cell Therapy and Technology Center, Hospital de Clinicas de Porto Alegre, HCPA, Porto Alegre, Ramiro Barcelos 2350-90035903, Brazil, Tel: 55 51 3359 8000; E-mail: lsilla@hcpa.edu.br