Ana Helena da Rosa Paz

Betacellulin Overexpression in Mesenchymal Stem Cells Induces Insulin Secretion In Vitro and Ameliorates Streptozotocin-Induced Hyperglycemia in Rats

Betacellulin (BTC), a ligand of the epidermal growth factor receptor, has been shown to promote growth and differentiation of pancreatic β-cells and to improve glucose metabolism in experimental diabetic rodent models. Mesenchymal stem cells (MSCs) have been already proved to be multipotent. Recent work has attributed to rat and human MSCs the potential to differentiate into insulin-secreting cells. Our goal was to transfect rat MSCs with a plasmid containing BTC cDNA to guide MSC differentiation into insulin-producing cells. Prior to induction of cell MSC transfection, MSCs were characterized by flow cytometry and the ability to in vitro differentiate into mesoderm cell types was evaluated. After rat MSC characterization, these cells were electroporated with a plasmid containing BTC cDNA. Transfected cells were cultivated in Dulbeccos modified Eagle medium high glucose (H-DMEM) with 10 mM nicotinamide. Then, the capability of MSC-BTC to produce insulin in vitro and in vivo was evaluated. It was possible to demonstrate by radioimmunoassay analysis that 10(4) MSC-BTC cells produced up to 0.4 ng/mL of insulin, whereas MSCs transfected with the empty vector (negative control) produced no detectable insulin levels. Moreover, MSC-BTC were positive for insulin in immunohistochemistry assay. In parallel, the expression of pancreatic marker genes was demonstrated by molecular analysis of MSC-BTC. Further, when MSC-BTC were transplanted to streptozotocin diabetic rats, BTC-transfected cells ameliorated hyperglycemia from over 500 to about 200 mg/dL at 35 days post-cell transplantation. In this way, our results clearly demonstrate that BTC overabundance enhances glucose-induced insulin secretion in MSCs in vitro as well as in vivo.

Cell therapy for chemically induced ovarian failure in mice.

Cell therapy has been linked to an unexplained return of ovarian function and fertility in some cancer survivors. Studies modeling this in mice have shown that cells transplantation generates donor-derived oocytes in chemotherapy-treated recipients. This study was conducted to further clarify the impact of cell transplantation from different sources on female reproductive function after chemotherapy using a preclinical mouse model. Methods. Female mice were administered 7.5 mg/kg cisplatin followed by cell transplantation (one week later) using GFP+ female cell donors. For cell tracking, adipose derived stem cell GFP+ (ADSC), female germline stem cell GFP+/MVH+ (FGSC), or ovary cell suspension GFP+ mice were transplanted into cisplatin-treated wild-type recipients. After 7 or 14 days animals were killed and histological analysis, IHQ for GFP cells, and ELISA for estradiol were performed. Results. Histological examinations showed that ADSC, ovary cell suspension, and FGSC transplant increase the number of follicles with apparent normal structure in the cells recipient group euthanized on day 7. Cell tracking showed GFP+ samples 7 days after transplant. Conclusion. These data suggest that intraovarian injection of ADSCs and FGSC into mice with chemotherapy-induced ovarian failure diminished the damage caused by cisplatin.

Intravenous vs intraperitoneal mesenchymal stem cells administration: What is the best route for treating experimental colitis?

AIM To investigate the therapeutic effects of mesenchymal stem cells (MSCs) transplanted intraperitoneally and intravenously in a murine model of colitis. METHODS MSCs were isolated from C57BL/6 mouse adipose tissue. MSC cultures were analyzed according to morphology, cellular differentiation potential, and surface molecular markers. Experimental acute colitis was induced in C57BL/6 mice by oral administration of 2% dextran sulfate sodium (DSS) in drinking water ad libitum from days 0 to 7. Colitis mice were treated with 1 × 10(6) MSCs via intraperitoneal or intravenous injection on days 2 and 5. The disease activity index was determined daily based on the following parameters: weight loss, stool consistency and presence of blood in the feces and anus. To compare morphological and functional differences in tissue regeneration between different MSC injection modalities, mice were euthanized on day 8, and their colons were examined for length, weight, and histopathological changes. Inflammatory responses were determined by measuring the levels of different serum cytokines using a CBA Th1/Th2/Th17 kit. Apoptotic rates were evaluated by terminal deoxynucleotidyl transferase-mediated dUDP-biotin nick end labeling assay. RESULTS Intravenous infusion of MSCs was more effective than intraperitoneal treatment (P < 0.001) in reducing the clinical and histopathologic severity of colitis, which includes weight loss, diarrhea and inflammation. An histological evaluation demonstrated decreased colonic inflammation based on reduced crypt loss and reduced infiltration of inflammatory cells. This therapeutic effect was most likely mediated by the down-regulation of pro-inflammatory cytokines [interleukin (IL)-6 and tumor necrosis factor (TNF)]; and by the up-regulation of anti-inflammatory cytokines (IL-10 and IL-4). Intravenous transplantation also induced high levels of IFN that lead to activation of the immunosuppressive activity of the MSCs, which did not occur with intraperitoneal transplantation (P = 0.006). An increase in apoptotic T cells was observed after intravenous, but not intraperitoneal, MSC infusion, suggesting that MSCs can induce apoptosis in resistant T cells in colonic inflammation (P = 0.027). CONCLUSION Our results demonstrate that intravenous treatment is a superior method for reducing colon inflammation compared with intraperitoneal therapy.

Utilização de células-tronco autólogas de medula óssea na regeneração do nervo tibial de coelhos mediante técnica de tubulização com prótese de silicone

This study presents an experimental model of an acute deffect in a peripheral nerve to evaluate neural regeneration using a tubulization technique associated with the inoculation of autologous stem cells from bone marrow. A total of 12 New Zealand white rabbits underwent a bilateral dissection of the tibial nerve followed by repair with silicone tubulization. On the left tibial nerve of all animals, the tube was filled with autologous bone marrow-derived stem cells collected from the humerus. For control, using the same repair technique, the tubes were filled with a NaCl solution in the right tibial nerve. After 30 days of observation, the animals were euthanized and a histological evaluation of the collected nerve segments was performed by staining with hematoxylin-eosin, luxol fast blue, and toluidine blue. From the results it is possible to conclude that the transplanted autologous stem cells associated with the tubulization technique present an advantage in the peripheral nerve regeneration process.

Germinative testicular cells and bone marrow mononuclear cells transplanted to a rat model of testicular degeneration.

The aim of this study was to evaluate the ability of rat mononuclear bone marrow cells to recover testis cell associations and multiplication in busulfan-treated rats, and to compare these data to germinative testicular cell transplant. The germinative testicular cells were obtained by the trypsin digestion method, and bone marrow cells were harvested from femurs and tibias, and purified using by Ficoll gradient. Cell transplantation was performed by the injection of cells through the efferent ducts into the rete testis in busulfan-treated animals. Fifteen days after transplantation, the recipient rats were sacrificed and the testes were collected and analyzed by histology (hematoxilin-eosin and DAPI staining). Results demonstrated that germ cells transplantation promoted cellular reorganization of seminiferous epithelium 15 days later. On the other hand, no improvement in spermatogenesis regeneration was found after heterologous mononuclear bone marrow cell transplantation.

Dexamethasone and azathioprine promote cytoskeletal changes and affect mesenchymal stem cell migratory behavior.

Glucocorticoids and immunosuppressive drugs are commonly used to treat inflammatory disorders, such as inflammatory bowel disease (IBD), and despite a few improvements, the remission of IBD is still difficult to maintain. Due to their immunomodulatory properties, mesenchymal stem cells (MSCs) have emerged as regulators of the immune response, and their viability and activation of their migratory properties are essential for successful cell therapy. However, little is known about the effects of immunosuppressant drugs used in IBD treatment on MSC behavior. The aim of this study was to evaluate MSC viability, nuclear morphometry, cell polarity, F-actin and focal adhesion kinase (FAK) distribution, and cell migratory properties in the presence of the immunosuppressive drugs azathioprine (AZA) and dexamethasone (DEX). After an initial characterization, MSCs were treated with DEX (10 μM) or AZA (1 μM) for 24 hrs or 7 days. Neither drug had an effect on cell viability or nuclear morphometry. However, AZA treatment induced a more elongated cell shape, while DEX was associated with a more rounded cell shape (P < 0.05) with a higher presence of ventral actin stress fibers (P < 0.05) and a decrease in protrusion stability. After 7 days of treatment, AZA improved the cell spatial trajectory (ST) and increased the migration speed (24.35%, P < 0.05, n = 4), while DEX impaired ST and migration speed after 24 hrs and 7 days of treatment (-28.69% and -25.37%, respectively; P < 0.05, n = 4). In conclusion, our data suggest that these immunosuppressive drugs each affect MSC morphology and migratory capacity differently, possibly impacting the success of cell therapy.

Comparison of human mesenchymal stromal cells from four neonatal tissues: Amniotic membrane, chorionic membrane, placental decidua and umbilical cord

BACKGROUND Mesenchymal stromal cells (MSCs) are being investigated as a potential alternative for cellular therapy. This study was designed to compare the biological characteristics of MSCs isolated from amniotic membrane (A-MSCs), chorionic membrane (C-MSCs), placental decidua (D-MSCs) and umbilical cord (UC-MSCs) to ascertain whether any one of these sources is superior to the others for cellular therapy purposes. METHODS MSCs were isolated from amniotic membrane, chorionic membrane, umbilical cord and placental decidua. Immunophenotype, differentiation ability, cell size, cell complexity, polarity index and growth kinetics of MSCs isolated from these four sources were analyzed. RESULTS MSCs were successfully isolated from all four sources. Surface marker profile and differentiation ability were consistent with human MSCs. C-MSCs in suspension were the smallest cells, whereas UC-MSCs presented the greatest length and least width. A-MSCs had the lowest polarity index and UC-MSCs, as more elongated cells, the highest. C-MSCs, D-MSCs and UC-MSCs exhibited similar growth capacity until passage 8 (P8); C-MSCs presented better lifespan, whereas insignificant proliferation was observed in A-MSCs. DISCUSSION Neonatal and maternal tissues can serve as sources of multipotent stem cells. Some characteristics of MSCs obtained from four neonatal tissues were compared and differences were observed. Amniotic membrane was the least useful source of MSCs, whereas chorionic membrane and umbilical cord were considered good options for future use in cell therapy because of the known advantages of immature cells.

Dynamic culture improves MSC adhesion on freeze-dried bone as a scaffold for bone engineering.

AIM To investigate the interaction between mesenchymal stem cells (MSCs) and bone grafts using two different cultivation methods: static and dynamic. METHODS MSCs were isolated from rat bone marrow. MSC culture was analyzed according to the morphology, cell differentiation potential, and surface molecular markers. Before cell culture, freeze-dried bone (FDB) was maintained in culture for 3 d in order to verify culture medium pH. MSCs were co-cultured with FDB using two different cultivation methods: static co-culture (two-dimensional) and dynamic co-culture (three-dimensional). After 24 h of cultivation by dynamic or static methods, histological analysis of Cell adhesion on FDB was performed. Cell viability was assessed by the Trypan Blue exclusion method on days 0, 3 and 6 after dynamic or static culture. Adherent cells were detached from FDB surface, stained with Trypan Blue, and quantified to determine whether the cells remained on the graft surface in prolonged non-dynamic culture. Statistical analyses were performed with SPSS and a P < 0.05 was considered significant. RESULTS The results showed a clear potential for adipogenic and osteogenic differentiation of MSC cultures. Rat MSCs were positive for CD44, CD90 and CD29 and negative for CD34, CD45 and CD11bc. FDBs were maintained in culture for 3 d and the results showed there was no significant variation in the culture medium pH with FDB compared to pure medium pH (P > 0.05). In histological analysis, there was a significant difference in the amount of adhered cells on FDB between the two cultivation methods (P < 0.05). The MSCs in the dynamic co-culture method demonstrated greater adhesion on the bone surface than in static co-culture method. On day 0, the cell viability in the dynamic system was significantly higher than in the static system (P < 0.05). There was a statistical difference in cell viability between days 0, 3 and 6 after dynamic culture (P < 0.05). In static culture, cell viability on day 6 was significantly lower than on day 3 and 0 (P < 0.05). CONCLUSION An alternative cultivation method was developed to improve the MSCs adhesion on FDB, demonstrating that dynamic co-culture provides a superior environment over static conditions.

Treatment of dilated cardiomyopathy in rabbits with mesenchymal stem cell transplantation and platelet-rich plasma

Dilated cardiomyopathy (DCM) is a major cause of cardiovascular mortality and morbidity, and there is evidence to suggest that stem cell transplantation may be a viable treatment option for this condition. Therefore, the goal of the present study was to assess myocardial regeneration in rabbits with doxorubicin-induced DCM treated with adipose mesenchymal stem cells (MSC) alone or in combination with platelet-rich plasma (PRP). Twenty New Zealand rabbits received doxorubicin for the induction of DCM and were divided into four groups according to treatment: saline, MSC, PRP and MSC + RP. Treatment agents were injected directly into the left ventricular myocardium following a thoracoscopy. Rabbits were assessed through echocardiographic and electrocardiographic examinations, as well as serum cardiac troponin I measurements at baseline, after the induction of DCM and 15 days after treatment. Animals were euthanased following the last assessment, and hearts were collected for histopathological analyses. The MSC group showed improvements in all parameters assessed, while the PRP group showed significantly impaired heart function. Histopathology of the heart revealed that the MSC group displayed the lowest number of lesions, while rabbits in the MSC + PRP, saline and PRP groups had steadily advancing lesions. These results suggest that MSC transplantation can improve heart function in rabbits with DCM, and underscore the need for further studies of the effects of PRP on the myocardium.

Isolation of human mesenchymal stem cells from amnion, chorion, placental decidua and umbilical cord: comparison of four enzymatic protocols

ObjectiveTo compare four enzymatic protocols for mesenchymal stem cells (MSCs) isolation from amniotic (A-MSC) and chorionic (C-MSC) membranes, umbilical cord (UC-MSC) and placental decidua (D-MSC) in order to define a robust, practical and low-cost protocol for each tissue.ResultsA-MSCs and UC-MSCs could be isolated from all samples using trypsin/collagenase-based protocols; C-MSCs could be isolated from all samples with collagenase- and trypsin/collagenase-based protocols; D-MSCs were isolated from all samples exclusively with a collagenase-based protocol.ConclusionsThe trypsin-only protocol was least efficient; the collagenase-only protocol was best for C-MSCs and D-MSCs; the combination of trypsin and collagenase was best for UC-MSCs and none of tested protocols was adequate for A-MSCs isolation.