Julio Cesar Francisco

Evaluation of Bone Marrow Mesenchymal Stem Cell Standard Cryopreservation Procedure Efficiency

INTRODUCTION Mesenchymal stem cells are obtained from a variety of sources, particularly bone marrow. These cells have great potential for clinical research due to their potential to regenerate tissue. As is well known, the cryopreservation process can store any cell type, particularly blood cells, for an indeterminate time. OBJECTIVE The aim of this study was to analyze the efficiency of standard cryopreservation procedures for adult mesenchymal stem cells from bone marrow. METHODS Mononuclear stem cells isolated from 10 Wistar male rats were cultivated for 4 weeks to obtain mesenchymal stem cells. The parameters considered in this study were trypan blue exclusion test and annexin V conjugated with 7-amino-actinomycin for flow cytometry before cryopreservation in liquid nitrogen vapor phase for 1 month and after thawing. RESULTS The viabilities determined by the trypan blue exclusion test were 94.76% and 90.58%, and the flow cytometry assay (annexin V conjugated with 7-amino-actinomycin) were 85.52% and 66.25%, before cryopreservation and after thawing, respectively. CONCLUSIONS Standard procedures for cryopreservation were not efficient for those cells. The flow cytometry assay was more sensitive than the trypan blue exclusion test to demonstrate nonviability.

Functional Outcome of Bone Marrow Stem Cells (CD45+/CD34−) After Cell Therapy in Acute Spinal Cord Injury: In Exercise Training and in Sedentary Rats

BACKGROUND Cell therapy and exercise training may be options for spinal cord regeneration. Our objective was to evaluate the functional effects of autologous bone marrow stem cell (CD45(+)/CD34(-)) transplantation in acute spinal cord injury in exercise training and in sedentary rats. MATERIALS AND METHODS Fifty-five adult male Wistar rats underwent spinal cord contusion by Impactor (NYU). Locomotor rating scale was performed every 48 hours for 48 days. Animals with scores < or = 12 were randomly divided into 4 groups: sedentary without parenchymal cell infusion; sedentary with parenchymal cell infusion; swimming training without parenchymal cell infusion; and swimming training with parenchymal cell infusion. Bone marrow stem cells were isolated by puncture-aspiration of the bone marrow and density gradient (d = 1.077). The animals underwent a 60-minute swimming session 6 times/week supporting an overload of 3% of body weight for 6 consecutive weeks. Comparisons between the groups in relation to differences between the beginning to the end of scores used the nonparametric Bonferroni test and post-hoc Mann-Whitney U test to identify significance. RESULTS Forty-two rats that obtained scores < or = 12 underwent therapy with 9 animals in each of the 4 groups as completors (n = 36). There was significance (P < or = .008) for sedentary without parenchymal cell infusion vs swimming training with parenchymal cell infusion. CONCLUSION The combination of bone marrow stem cell therapy (CD45(+)/CD34(-)) and exercise training resulted in significant functional improvement in acute spinal cord injury.

Comparison of mononuclear and mesenchymal stem cell transplantation in myocardium infarction

Background: Bone marrow stem cell (SC) transplantation into failing myocardium has emerged as a novel therapeutic option for the treatment of ventricular dysfunction. Both mononuclear (MoSC) and mesenchymal (MeSC) stem cells have been proposed as ideal cell types to this goal. The objective of this study is to compare the efficacy of these cells in improving ventricular function in a rat model of postinfarct ventricular dysfunction. Method: Myocardial infarction was induced in Wistar rats by left coronary occlusion. After 1 week, 42 animals with resulting ejection fractions (EF) lower than 30% were included in the study. MoSC and MeSC were obtained from bone marrow aspirates and separated by the Ficoll-Hypaque method. MeSC were cultured for 14 days before injection. Nine days after infarction, rats received intramyocardial injections of MoSC (n=8), MeSC (n=13) or culture medium as a control (n=21). Echocardiographic evaluation was performed at baseline and after one month. Results: There were no significant differences in the baseline ejection fractions or the left ventricular end diastolic volumes (LVEDV) between all groups. After 1 month, ejection fraction decreased in the Control Group and remained unchanged in MoSC and MeSC Groups. In all three groups ventricular dilation was observed. Histopathology of the infarcted area where injections were performed identified new smooth muscle cells and endothelial cells in the MeSC Group and only new endothelial cells in MoSC Group Conclusions: Both MoSC and MeSC provided stabilization in the ejection fraction in this post-infarction ventricular dysfunction model however, no therapy prevented ventricular dilation.

Transplantation of SNAP-treated adipose tissue-derived stem cells improves cardiac function and induces neovascularization after myocardium infarct in rats

Stem cell therapy has been considered a promise for damaged myocardial tissue. We have previously shown that S-nitroso-N-acetyl-D,L-penicillamine (SNAP) increases the expression of several muscular markers and VEGF in mesenchymal stem cells, indicating that transplantation of SNAP-treated cells could provide better functional outcomes. Here, we transplanted SNAP-treated adipose tissue-derived stem cells (ADSCs) in rat infarcted myocardium. After 30days, we observed a significant improvement of the ejection fraction in rats that received SNAP-treated ADSCs, compared with those that received untreated cells (p=0.008). Immunohistochemical reactions showed an increased expression of troponin T-C and von Willebrand factor, and organized vascular units in the infarcted area of tissue transplanted with treated ADSCs. SNAP exposure induced intracellular S-nitrosation, a decreased GSH/GSSG ratio, but did not increase cGMP levels. Collectively, these results indicate that SNAP alters the redox environment of ADSCs, possibly associated with a pre-differentiation state, which may improve cardiac function after transplantation.

O transplante em conjunto de células mioblásticas esqueléticas e mesenquimais (cocultivadas) na disfunção ventricular pós-infarto do miocárdio

OBJECTIVE: Cell therapy in the myocardium has been mainly performed with satisfactory results using 2 cell types: skeletal myoblasts (myogenic) and mesenchymal cells (angiogenic). This study assessed the combined transplantation of those 2 cell types (SMM) into infarcted rats. METHODS: Myocardial infarction was induced by ligature of the left coronary artery in 26 Wistar rats. After one week, the animals underwent echocardiography for assessing ejection fraction (EF%) and left ventricular end-diastolic and systolic volumes (EDV, ESV, mL). After 2 days, the animals were reoperated on and divided into 2 groups: 1) control (n=10), which received 0.15 mL of culture medium; and 2) SMM (n=16), which received 7.5x106 heterologous skeletal myoblasts and mesenchymal cells in the infarcted region. The cells were obtained from puncture of the iliac crest and biopsy of skeletal muscle, and were cultured in vitro. After one month, the animals underwent a new echocardiography. RESULTS: No significant difference in EF, EDV, and ESV was observed between the 2 groups on baseline echocardiographic values. One month after transplantation, the following was observed: a reduction in EF in the control group (29.31 ± 5.6% to 23.54 ± 6.51%; P=0.048); and an increase in EF in the SMM group (24.03 ± 8.68% to 31.77 ± 9.06%; P=0.011). The presence of neovascularization and muscle fibers was identified in the regions of myocardial fibrosis in the SMM group. CONCLUSION: Cocultivation of skeletal myoblasts and mesenchymal cells is functionally effective.

Controversies About the Chromosomal Stability of Cultivated Mesenchymal Stem Cells: Their Clinical Use is it Safe?

The usefulness of adult stem cells in research and therapeutic applications highly relies on their genomic integrity and stability. Many laboratories including ours have addressed this concern using methods such as karyotyping, Qbanding, fluorescent in situ hybridization, array CGH, flow cytometry and Pap test to evaluate number and structure of chromosomes and cellular phenotype. This review attempts to summarize the findings reported so far for the studies on chromosomal aberrations in adult stem cells and warrant to perform certain basic tests before transplantation to avoid any adverse reactions, which will thus aid in better therapeutic output after cellular transplantation in the treatment of various diseases.

Effect of exercise associated with stem cell transplantation on ventricular function in rats after acute myocardial infarction

OBJECTIVE To analyze the functional and anatomical-pathological effect of transplantation of bone marrow mononuclear cells associated to aquatic physical activity after myocardial infarction in rats. METHODS Twenty-one rats were induced by myocardial infarction, through left coronary artery ligation. After a week, the animals were subjected to echocardiography for evaluation of left ventricle ejection fraction (LVEF, %) and dyastolic and end systolic volume of the left ventricle (EDV, ESV, ml), randomized and the transplantation of mononuclear stem cells. The animals were divided into four groups: sedentary group without cells (n=5), sedentary with cells (n=5), trained without cells (n=5) and trained with cells (n=6). The physical training was started 30 days after infarction and held in swimming during 30 days. At the beginning and at the end of the physical training protocol were held assay of lactate. The animals have been subjected to new echocardiography after 60 days of myocardial infarction. RESULTS Two months after the transplant, were observed decrease in FE in the control group (35.2 to 23.54 P=0.022) and addition of LVEF and stabilization of ventricular remodeling in the group trained with cells (29.85 to 33.43% P=0.062 and 0.71 to 0.73 ml, P=0.776, respectively). Identified the reduction of collagen fibers, myocardial fibrosis regions in the group trained with and without cells. CONCLUSION The group trained with cells improves ventricular function compared to the control group, suggesting the benefit of associated cell therapy will physical activity.

Functional outcome of bone marrow stem cells (CD45(+)/CD34(-)) after cell therapy in chronic spinal cord injury in Wistar rats.

BACKGROUND Therapy with diverse cell types has been proposed to regenerate spinal cord injuries seeking to minimize the consequences for the lives of chronic patients. The types considered are: mononuclear and mesenchymal adult stem cells, embryonic stem cells, and Schwann cells. MATERIALS AND METHODS Ninety male Wistar rats that underwent spinal cord contusion injury (NYU Impactor) were followed with the Basso, Beattie, and Bresnahan (BBB) locomotor rating scale for 14 days. Animals with scores < or = 16 were randomly divided into 2 groups: control (vehicle) versus cell therapy group. The mononuclear fraction (CD45(+)/CD34(-)) obtained by puncture-aspiration of the bone marrow was isolated by a density gradient (d = 1.077). The parenchymal cell infusion was performed using a syringe (100 U/1 mL) with a 30G1/2 needle. The animals were followed for 10 days before euthanasia. Statistical analyses comparing groups were performed by the Mann-Whitney test and group comparisons by the Wilcoxon test. RESULTS Among 90 injured rats, 65 (72.2%) survived, including 44 whose scores were < or = 16. Eleven animals finished the study in the control group (64.7%) and 17 in the therapy group (80.9%). The statistical analyses did not demonstrate significance (P > .05) for either test. CONCLUSION Mononuclear adult stem cell therapy was not demonstrated to be functionally effective for chronic spinal cord injury.

Autologous Fat Grafting for Treatment of Breast Implant Capsular Contracture: A Study in Pigs

BACKGROUND Capsular contracture (CC) is a common complication after breast augmentation. Autologous fat grafting may be effective for restoring tissue vascularization and function. OBJECTIVE The authors evaluated the efficacy of autologous fat grafting in a porcine model as a treatment for CC after breast augmentation. METHODS This prospective study was performed in 20 female 30-day-old pigs. Each animal was implanted with three 30-cc textured silicone implants (stage 1 of the experiment). Group A served as the untreated control group. To induce CC, 2 mL of autologous fibrin glue was applied to the pericapsular space in group B and C animals at implantation. Three months after implantation (stage 2), the CCs of all groups were assessed by Baker classification and applanation tonometry (AT). Liposuction was performed in group B to harvest fat for these animals. Three months after group B underwent fat grafting, all 3 groups were reevaluated. Reassessments included Baker classification, AT, histologic analysis, and tensiometry (stage 3). RESULTS The deposition of mature and immature collagen was similar for the 3 groups. The amount of fat remaining around the implanted capsules did not differ significantly between the groups. At stage 3, group B exhibited significantly larger tonometry areas than did group C. The CCs in groups B and C were significantly thicker than those of group A, but the difference between groups B and C was not significant. Capsule rupture forces did not differ significantly between groups A and B but were significantly higher in group C compared with the other groups. CONCLUSIONS Results in this animal model indicate that pericapsular lipoinjection may be a promising treatment for CC in humans.

Pap Test as the First Step in Screening Genetic Stability in Cell-BasedTherapy

The possibility of cell modifications compromises the safety of stem cell therapy under standardized conditions. The aim of this study was to analyze adipose tissue-derived mesenchymal stem cells (AT-MSCs) using the Pap test as a first screening step to evaluate genetic stability. Methods: Human adipose tissue from six healthy female donors was obtained from elective liposuction procedures. The cells were isolated, cultivated at P2/P3, characterized by flow cytometric analysis, and differentiation induced. The AT-MSCs were stained by Papanicolaou (Pap) staining and analyzed according to the Bethesda classification, and viability-apoptosis relationships were evaluated. Results: The Pap test for Sample I indicated high-grade alterations consistent with genetic instability; for Samples II-V, atypical cells of undetermined significance; and for Sample VI, normal cells. Conclusions: These results demonstrate the potential of using the Pap test as an initial screening step to evaluate the genetic stability of cultured AT-MSCs as well for other adherent stem cells.