Banca de DEFESA: FLAVIA ZATTAR PIAZERA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : FLAVIA ZATTAR PIAZERA
DATE: 18/03/2023
TIME: 09:00
LOCAL: Plataforma Teams
TITLE:

Characterization and evaluation of viability, immune markers and differentiation of cryopreserved human hematopoietic stem cells.

KEY WORDS:

apheresis; cryopreservation; ROS and ENOs; HLA typing; ABO typing; platellet-rich fibrin.

PAGES: 84
BIG AREA: Ciências da Saúde
AREA: Medicina
SUMMARY:

Introduction: Hematopoietic stem cells (HSC) have numerous therapeutic applications in
the treatment of hematologic malignancies, autoimmune diseases and in regenerative
medicine. The clinical, biochemical and immunological characteristics of individuals are
relevant factors in the quality of HSC collected and cryopreserved, thus interfering with the
results of hematopoietic stem cell transplants. Culture media and culture substrates are in
vitro models necessary to enable experimental research and therapeutic use. This study
aimed to characterize and evaluate the viability and immune markers of human HSC, as
well as to evaluate the role of platelet-rich fibrin (PRF) as a substrate for their cultivation.
Methods: This is a retrospective, descriptive and experimental study conducted with 14
HSC samples obtained by apheresis from 14 healthy adult individuals. The samples were
submitted to typing for HLA antigens by the SSO technique and ABO/Rh systems by
immunohematology. Viability and types of regulated killing were assessed by flow
cytometry. Reactive species were evaluated by flow cytometry (ROS/DCFDA;
ERNs/DAFFM Diacetate). HSC differentiation potential was evaluated using a PRF as
substrate; the results were tabulated and analyzed using the Prism 5.0 program. Results:
HSC donors were young adults with hematological and biochemical parameters within
normal reference values. The cryopreservation time of 34 ± 15 months reduced in 2% the
total HSC-CD34+. There was greater expression of the A*02, DRB1*04, DRB1*07 loci for
HLA antigens. As for the type of regulated cell death, there was no difference between the
percentages of initial apoptosis, late apoptosis and by unknown mechanism. As for the ABO
system, there was a predominance of type O (6 individuals), followed by type A (5
individuals). For the Rh factor there was a predominance of the positive type (10
individuals). After cryopreservation, there was great individual variability in the production
of reactive species and greater production of ERNs than ROS by the group of individuals.
The fibrin mesh favored the anticipation of cell grouping (homing / 2 days of incubation),
while in the absence of fibrin, grouping was observed after 3 days. The fibrin mesh favored
the appearance of signs of cell differentiation (pseudopods and evident nucleolus) after 3
days of incubation. Conclusion: The set of results showed that HSC cryopreservation
parameters should be considered to ensure their quality, as there was a reduction in cell
viability when thawed and some samples had mitochondrial metabolism close to 0 (zero).
Considering that, the PRF mesh provided adhesion, homing and cell differentiation signals,
it is believed that the parameters related to the freezing/thawing method and the
cryopreservation time were appropriate to guarantee the quality of the samples. However,
it is suggested the continuity of studies to determine the effect of the curve of time x cell
quality to help the decision making of national banks of stem cell cryopreservation.

BANKING MEMBERS:
Externo à Instituição - CARLOS ALBERTO PINTO DA SILVEIRA - FEPECS
Interno - 2676451 - CIRO MARTINS GOMES
Externo à Instituição - LEONEL ALVES DE OLIVEIRA - ANVISA
Presidente - 3424061 - SELMA APARECIDA SOUZA KUCKELHAUS
Externa ao Programa - 1010271 - TATIANA KARLA DOS SANTOS BORGES