Somatic mosaicism in patients with Fanconi anaemia: Proposal of alternative tissue for inconclusive diagnoses.

INTRODUCTION: Fanconi anaemia (FA) is a rare genetic disorder marked by progressive bone marrow failure, chromosomal fragility, and increased cancer susceptibility. Laboratory diagnosis includes chromosomal instability test and mutation investigation. A total of 15%-25% of all patients may have somatic mosaicism, characterized by two distinct haematopoietic cell populations, one resistant and one sensitive to agents that induce chromosomal breakage, which complicates the diagnosis by a high incidence of reverted cells leading to inconclusive or false-negative results. The study aimed to evaluate the use of bone marrow stromal mesenchymal cells (BM-MSCs) as an alternative, non-haematopoietic tissue for diagnosis. METHODS: Bone marrow mesenchymal stromal cells from 12 patients with positive diepoxybutane (DEB) tests were cultivated and analysed by cytogenetics and mutation investigation. RESULTS: The DEB test was performed at 0.1 and 0.01 µg/ml concentrations, with an index ranging from 0.24 to 1.00. At higher concentration, the metaphases number was lower, probably due to toxicity. Regarding the molecular investigation, all the mutations previously found in peripheral blood were identified on BM-MSC. CONCLUSION: This study demonstrated the possibility of using BM-MSCs as an alternative tissue for cytogenetic and molecular investigation. Future tests using an intermediate DEB concentration may lead to an optimal protocol that could be non-toxic to cells but provides conclusive results.

Chromosomal aberrations after induced pluripotent stem cells reprogramming.

Induced pluripotent stem cells (iPSCs) are generated from adult cells that have been reprogrammed to pluripotency. However, in vitro cultivation and genetic reprogramming increase genetic instability, which could result in chromosomal abnormalities. Maintenance of genetic stability after reprogramming is required for possible experimental and clinical applications. The aim of this study was to analyze chromosomal alterations by using the G-banding karyotyping method applied to 97 samples from 38 iPSC cell lines generated from peripheral blood or Wharton's jelly. Samples from patients with long QT syndrome, Jervell and Lange-Nielsen syndrome and amyotrophic lateral sclerosis and from normal individuals revealed the following chromosomal alterations: acentric fragments, chromosomal fusions, premature centromere divisions, double minutes, radial figures, ring chromosomes, polyploidies, inversions and trisomies. An analysis of two samples generated from Wharton's jelly before and after reprogramming showed that abnormal clones can emerge or be selected and generate an altered lineage. IPSC lines may show clonal and nonclonal chromosomal aberrations in several passages (from P6 to P34), but these aberrations are more common in later passages. Many important chromosomal aberrations were detected, showing that G-banding is very useful for evaluating genetic instability with important repercussions for the application of iPSC lines.

3D Telomere Structure Analysis to DetectGenomic Instability and Cytogenetic Evolutionin Myelodysplastic Syndromes.

The disease course of myelodysplastic syndromes (MDS) features chromosome instability and clonal evolution, leading to the sequential acquisition of novel cytogenetic aberrations and the accumulation of these abnormalities in the bone marrow. Although clonal cytogenetic abnormalities can be detected by conventional cytogenetics in 50% of patients with MDS, such distinguishing patterns are lacking in the other 50%. Despite the increase in the prognostic value of some biomarkers, none of them is specific and able to discriminate between stable and unstable patients that subsequently progress to acute myeloid leukemia. This pilot study aimed to investigate the potential use of the 3D telomere profiling to detect genomic instability in MDS patients with or without clonal cytogenetic evolution. The comparison between different time points in patients with cytogenetic changes showed that in the CD34+ MDS cells, there was a significant decrease in the total number of telomeric signals, the average intensity of signals and the total intensity of telomeres. By contrast, the number of aggregates increased during cytogenetic evolution (p < 0.001). This pattern was observed only for MDS patients with cytogenetic evolution but was absent in patients without cytogenetic changes. In conclusion, we demonstrated that the 3D nuclear telomere organization was significantly altered during the MDS disease course, and may have contributed to cytogenetic clonal evolution.

Combined Bone Marrow-Derived Mesenchymal Stromal Cell Therapy and One-Way Endobronchial Valve Placement in Patients with Pulmonary Emphysema: A Phase I Clinical Trial.

One-way endobronchial valves (EBV) insertion to reduce pulmonary air trapping has been used as therapy for chronic obstructive pulmonary disease (COPD) patients. However, local inflammation may result and can contribute to worsening of clinical status in these patients. We hypothesized that combined EBV insertion and intrabronchial administration of mesenchymal stromal cells (MSCs) would decrease the inflammatory process, thus mitigating EBV complications in severe COPD patients. This initial study sought to investigate the safety of this approach. For this purpose, a phase I, prospective, patient-blinded, randomized, placebo-controlled design was used. Heterogeneous advanced emphysema (Global Initiative for Chronic Lung Disease [GOLD] III or IV) patients randomly received either allogeneic bone marrow-derived MSCs (108 cells, EBV+MSC) or 0.9% saline solution (EBV) (n = 5 per group), bronchoscopically, just before insertion of one-way EBVs. Patients were evaluated 1, 7, 30, and 90 days after therapy. All patients completed the study protocol and 90-day follow-up. MSC delivery did not result in acute administration-related toxicity, serious adverse events, or death. No significant between-group differences were observed in overall number of adverse events, frequency of COPD exacerbations, or worsening of disease. Additionally, there were no significant differences in blood tests, lung function, or radiological outcomes. However, quality-of-life indicators were higher in EBV + MSC compared with EBV. EBV + MSC patients presented decreased levels of circulating C-reactive protein at 30 and 90 days, as well as BODE (Body mass index, airway Obstruction, Dyspnea, and Exercise index) and MMRC (Modified Medical Research Council) scores. Thus, combined use of EBV and MSCs appears to be safe in patients with severe COPD, providing a basis for subsequent investigations using MSCs as concomitant therapy. Stem Cells Translational Medicine 2017;6:962-969.

Emergence of clonal chromosomal alterations during the mesenchymal stromal cell cultivation.

BACKGROUND: Use of human mesenchymal stromal cells (MSCs) is a promising strategy for cell therapy in injured tissues recovery. However, MSCs acquire genetic changes when cultivated in vitro that make them more susceptible to undergo neoplastic transformation. Therefore, genomic integrity of stem cells should be monitored carefully for the use in basic research and clinical trials, including karyotype analysis to confirm the absence of genetic instability. Here, we report a case of a male 67-year-old patient selected to join the study: "Autologous transplantation of mesenchymal cells for treatment of severe and refractory ischemic cardiomyopathy". He underwent nephrectomy for malignant tumor on the right kidney. Cytogenetic analysis on a bone marrow sample showed a normal karyotype: 46,XY[20]. However, the MSC at second passage showed a hyperdiploid clone, with clonal trisomies of chromosomes 4, 5, 10 and X. In order to investigate more, another sample from the same patient was used for a second cultivation and, at third passage, these cells showed a clonal translocation t(9;18)(p24;q11). The recurrent aberrations in MSC may indicate the beginning of a spontaneous transformation in culture, so, these cells were not used for cell therapy. Several analyses were performed at the Center for Cell Technology (152 samples), however this was the only case to show clonal cytogenetic abnormalities. Interestingly, two distinct clonal alterations were seen in two parallel cell cultivations from the same patient, suggesting a propensity for genetic instability. This highlights the need to evaluate these cells on a case-by-case basis, especially in patients with a history of cancer. Although there is controversy about the use of cells with cytogenetic abnormality for therapy, because their tumorigenic doubtful potential, we decided against the use of these cells for regenerative medicine. CASE PRESENTATION: Here, we report a case of a male 67-year-old patient selected to join the study: "Autologous transplantation of mesenchymal cells for treatment of severe and refractory ischemic cardiomyopathy". He underwent nephrectomy for malignant tumor on the right kidney. Cytogenetic analysis on a bone marrow sample showed a normal karyotype: 46,XY[20]. However, the MSC at second passage showed a hyperdiploid clone, with clonal trisomies of chromosomes 4, 5, 10 and X. In order to investigate more, another sample from the same patient was used for a second cultivation and, at third passage, these cells showed a clonal translocation t(9;18)(p24;q11). The recurrent aberrations in MSC may indicate the beginning of a spontaneous transformation in culture, so, these cells were not used for cell therapy. Several analyses were performed at the Center for Cell Technology(152 samples), however this was the only case to show clonal cytogenetic abnormalities. Interestingly, two distinct clonal alterations were seen in two parallel cell cultivations from the same patient, suggesting a propensity for genetic instability. This highlights the need to evaluate these cells on a case-by-case basis, especially in patients with a history of cancer. CONCLUSIONS: Although there is controversy about the use of cells with cytogenetic abnormality for therapy, because their tumorigenic doubtful potential, we decided against the use of these cells forregenerative medicine.

Genetic evaluation of mesenchymal stem cells by G-banded karyotyping in a Cell Technology Center.

OBJECTIVE: To present the initial results of first three years of implementation of a genetic evaluation test for bone marrow-derived mesenchymal stem cells in a Cell Technology Center. METHODS: A retrospective study was carried out of 21 candidates for cell therapy. After the isolation of bone marrow mononuclear cells by density gradient, mesenchymal stem cells were cultivated and expanded at least until the second passage. Cytogenetic analyses were performed before and after cell expansion (62 samples) using G-banded karyotyping. RESULTS: All the samples analyzed, before and after cell expansion, had normal karyotypes, showing no clonal chromosomal changes. Signs of chromosomal instability were observed in 11 out of 21 patients (52%). From a total of 910 analyzed metaphases, five chromatid gaps, six chromatid breaks and 14 tetraploid cells were detected giving as total of 25 metaphases with chromosome damage (2.75%). CONCLUSION: The absence of clonal chromosomal aberrations in our results for G-banded karyotyping shows the maintenance of chromosomal stability of bone marrow-derived mesenchymal stem cells until the second passage; however, signs of chromosomal instability such as chromatid gaps, chromosome breaks and tetraploidy indicate that the long-term cultivation of these cells can provide an intermediate step for tumorigenesis.

Genetic evaluation of mesenchymal stem cells by G-banded karyotyping in a Cell Technology Center

OBJECTIVE: To present the initial results of first three years of implementation of a genetic evaluation test for bone marrow-derived mesenchymal stem cells in a Cell Technology Center. METHODS: A retrospective study was carried out of 21 candidates for cell therapy. After the isolation of bone marrow mononuclear cells by density gradient, mesenchymal stem cells were cultivated and expanded at least until the second passage. Cytogenetic analyses were performed before and after cell expansion (62 samples) using G-banded karyotyping. RESULTS: All the samples analyzed, before and after cell expansion, had normal karyotypes, showing no clonal chromosomal changes. Signs of chromosomal instability were observed in 11 out of 21 patients (52%). From a total of 910 analyzed metaphases, five chromatid gaps, six chromatid breaks and 14 tetraploid cells were detected giving as total of 25 metaphases with chromosome damage (2.75%). CONCLUSION: The absence of clonal chromosomal aberrations in our results for G-banded karyotyping shows the maintenance of chromosomal stability of bone marrow-derived mesenchymal stem cells until the second passage; however, signs of chromosomal instability such as chromatid gaps, chromosome breaks and tetraploidy indicate that the long-term cultivation of these cells can provide an intermediate step for tumorigenesis. .

Bone marrow stem cell transplantation and coronary artery bypass grafting surgery for chronic ischemic myocardiopathy.

We studied 12 consecutive patients with chronic ischemic myocardiopathy treated with bone marrow adult stem cell (ASC) transplantation and coronary artery bypass grafting (CABG). The aim of the study was to evaluate functional class (New York Heart Association), wall motion score index (WMSI), and ejection fraction by echocardiography and to evaluate myocardial perfusion by single-photon emission computed tomography (SPECT). Follow-up evaluations were performed at 3, 6, and 12 months. The results revealed functional class improvement until 12 months, a progressive increase in the ejection fraction of 15% to 20% in the first 6 months, and a progressive increase in the WMSI by 35% to 45% in 12 months. Evaluation of the WMSI in the stem cell and CABG areas separately revealed a similar improvement in the first 3 months and a better progression in the CABG area. SPECT images revealed perfusion improvements in ischemic areas and no difference in fibrous tissue areas. These preliminary results show the safety of the method and its reproducibility. When performed concomitantly with CABG, bone marrow ASC transplantation may improve functional class, ejection fraction, WMSI, and myocardial perfusion. This study will be completed with all patients followed up for 12 months and compared with a control group.

New recurrent deletions in the PPARgamma and TP53 genes are associated with childhood myelodysplastic syndrome.

Myelodysplastic syndrome (MDS) is a rare hematological malignancy in children. It was performed FISH analysis in 19 pediatric MDS patients to investigate deletions involving the PPARgamma and TP53 genes. Significant losses in the PPARgamma gene and deletions in the tumor suppressor gene TP53 were observed in 17 and 18 cases, respectively. Using quantitative RT-PCR, it was detected PPARgamma transcript downexpression in a subset of these cases. G-banding analysis revealed 17p deletions in a small number of these cases. One MDS therapy-related patient had neither a loss of PPARgamma nor TP53. These data suggest that the PPARgamma and TP53 genes may be candidates for molecular markers in pediatric MDS, and that these potentially recurrent deletions could contribute to the identification of therapeutic approaches in primary pediatric MDS.