Objective: Allogeneic mesenchymal stromal cells (MSCs) are used in the 1-stage treatment of articular cartilage defects. The aim of this study is to investigate whether transport of mitochondria... Show moreObjective: Allogeneic mesenchymal stromal cells (MSCs) are used in the 1-stage treatment of articular cartilage defects. The aim of this study is to investigate whether transport of mitochondria exists between chondrocytes and MSCs and to investigate whether the transfer of mitochondria to chondrocytes contributes to the mechanism of action of MSCs. Design: Chondrocytes and MSCs were stained with MitoTracker, and CellTrace was used to distinguish between cell types. The uptake of fluorescent mitochondria was measured in cocultures using flow cytometry. Transport was visualized using fluorescence microscopy. Microvesicles were isolated and the presence of mitochondria was assessed. Mitochondria were isolated from MSCs and transferred to chondrocytes using MitoCeption. Pellets of chondrocytes, chondrocytes with transferred MSC mitochondria, and cocultures were cultured for 28 days. DNA content and proteoglycan content were measured. Mitochondrial DNA of cultured pellets and of repair cartilage tissue was quantified. Results: Mitochondrial transfer occurred bidirectionally within the first 4 hours until 16 hours of coculture. Transport took place via tunneling nanotubes, direct cell-cell contact, and extracellular vesicles. After 28 days of pellet culture, DNA content and proteoglycan deposition were higher in chondrocyte pellets to which MSC mitochondria were transferred than the control groups. No donor mitochondrial DNA was traceable in the biopsies, whereas an increase in MSC mitochondrial DNA was seen in the pellets. Conclusions: These results suggest that mitochondrial transport plays a role in the chondroinductive effect of MSCs on chondrocytes in vitro. However, in vivo no transferred mitochondria could be traced back after 1 year. Show less
Simple Summary: For the last 20 years, measurable residual disease (MRD) has proven to be a strong prognostic factor in B-cell precursor acute lymphoblastic leukemia (BCP-ALL). However, the effects... Show moreSimple Summary: For the last 20 years, measurable residual disease (MRD) has proven to be a strong prognostic factor in B-cell precursor acute lymphoblastic leukemia (BCP-ALL). However, the effects of therapy on the bone marrow (BM) microenvironment and their potential relationship with MRD and patient outcome still remain to be evaluated. Here, we show that mesenchymal stem cells (MSC) and endothelial cells (EC) are constantly present at relatively low frequencies in normal BM and in most follow-up BM samples from treated BCP-ALL patients. Of note, their levels are independent of the MRD status. From the prognostic point of view, an increased percentage of EC among stromal cells (EC plus MSC) at day +78 of therapy was associated with shorter disease free survival (DFS), independently of the MRD status both in childhood and in adult BCP-ALL. Thus, an abnormally high EC/MSC distribution at day +78 of therapy emerges as an adverse prognostic factor, independent of MRD in BCP-ALL. For the last two decades, measurable residual disease (MRD) has become one of the most powerful independent prognostic factors in B-cell precursor acute lymphoblastic leukemia (BCP-ALL). However, the effect of therapy on the bone marrow (BM) microenvironment and its potential relationship with the MRD status and disease free survival (DFS) still remain to be investigated. Here we analyzed the distribution of mesenchymal stem cells (MSC) and endothelial cells (EC) in the BM of treated BCP-ALL patients, and its relationship with the BM MRD status and patient outcome. For this purpose, the BM MRD status and EC/MSC regeneration profile were analyzed by multiparameter flow cytometry (MFC) in 16 control BM (10 children; 6 adults) and 1204 BM samples from 347 children and 100 adult BCP-ALL patients studied at diagnosis (129 children; 100 adults) and follow-up (824 childhood samples; 151 adult samples). Patients were grouped into a discovery cohort (116 pediatric BCP-ALL patients; 338 samples) and two validation cohorts (74 pediatric BCP-ALL, 211 samples; and 74 adult BCP-ALL patients; 134 samples). Stromal cells (i.e., EC and MSC) were detected at relatively low frequencies in all control BM (16/16; 100%) and in most BCP-ALL follow-up samples (874/975; 90%), while they were undetected in BCP-ALL BM at diagnosis. In control BM samples, the overall percentage of EC plus MSC was higher in children than adults (p = 0.011), but with a similar EC/MSC ratio in both groups. According to the MRD status similar frequencies of both types of BM stromal cells were detected in BCP-ALL BM studied at different time points during the follow-up. Univariate analysis (including all relevant prognostic factors together with the percentage of stromal cells) performed in the discovery cohort was used to select covariates for a multivariate Cox regression model for predicting patient DFS. Of note, an increased percentage of EC (>32%) within the BCP-ALL BM stromal cell compartment at day +78 of therapy emerged as an independent unfavorable prognostic factor for DFS in childhood BCP-ALL in the discovery cohort-hazard ratio (95% confidence interval) of 2.50 (1-9.66); p = 0.05-together with the BM MRD status (p = 0.031). Further investigation of the predictive value of the combination of these two variables (%EC within stromal cells and MRD status at day +78) allowed classification of BCP-ALL into three risk groups with median DFS of: 3.9, 3.1 and 1.1 years, respectively (p = 0.001). These results were confirmed in two validation cohorts of childhood BCP-ALL (n = 74) (p = 0.001) and adult BCP-ALL (n = 40) (p = 0.004) treated at different centers. In summary, our findings suggest that an imbalanced EC/MSC ratio in BM at day +78 of therapy is associated with a shorter DFS of BCP-ALL patients, independently of their MRD status. Further prospective studies are needed to better understand the pathogenic mechanisms involved. Show less
BACKGROUND: After renal transplantation, there is a need of immunosuppressive regimens that effectively prevent allograft rejection while minimizing cardiovascular complications. This substudy of... Show moreBACKGROUND: After renal transplantation, there is a need of immunosuppressive regimens that effectively prevent allograft rejection while minimizing cardiovascular complications. This substudy of the TRITON trial evaluated the cardiovascular effects of autologous bone marrow-derived mesenchymal stromal cells (MSCs) in renal transplant recipients.METHODS AND RESULTS: Renal transplant recipients were randomized to MSC therapy, infused at weeks 6 and 7 after transplantation, with withdrawal at week 8 of tacrolimus or standard tacrolimus dose. Fifty-four patients (MSC group=27; control group=27) underwent transthoracic echocardiography at weeks 4 and 24 after transplantation and were included in this substudy. Changes in clinical and echocardiographic variables were compared. The MSC group showed a benefit in blood pressure control, assessed by a significant interaction between changes in diastolic blood pressure and the treatment group (P=0.005), and a higher proportion of patients achieving the predefined blood pressure target of <140/90 mm Hg compared with the control group (59.3% versus 29.6%, P=0.03). A significant reduction in left ventricular mass index was observed in the MSC group, whereas there were no changes in the control group (P=0.002). The proportion of patients with left ventricular hypertrophy decreased at 24 weeks in the MSC group (33.3% versus 70.4%, P=0.006), whereas no changes were noted in the control group (63.0% versus 48.1%, P=0.29). Additionally, MSC therapy prevented progressive left ventricular diastolic dysfunction, as demonstrated by changes in mitral deceleration time and tricuspid regurgitant jet velocity.CONCLUSIONS: MSC strategy is associated with improved blood pressure control, regression of left ventricular hypertrophy, and prevention of progressive diastolic dysfunction at 24 weeks after transplantation. Registration URL: ; Unique identifier: NCT03398681. Show less
Simple SummarySarcomas are rare cancers of mesenchymal origin, the majority of which are characterized by many copy number alterations, amplifications, or deletions. Because of these complex... Show moreSimple SummarySarcomas are rare cancers of mesenchymal origin, the majority of which are characterized by many copy number alterations, amplifications, or deletions. Because of these complex genomics, it is notoriously difficult to identify driver events of malignant transformation. In this study, we show that murine and canine mesenchymal stem cells (MSCs) can be used to model spontaneous malignant transformation towards sarcomas with complex genomics. We show that these MSCs have an abnormal karyotype, many structural variants, and point mutations at whole genome sequencing analysis, and form sarcomas after injection into mice. Our cross-species analysis reveals that p53 loss is an early event in sarcomagenesis, and it was shown that MSCs with a knock-out in Trp53 transform earlier compared to wild-type MSCs. Our study points to the importance of p53 loss in the transformation process towards sarcomas with complex genomics.Sarcomas are rare mesenchymal tumors with a broad histological spectrum, but they can be divided into two groups based on molecular pathology: sarcomas with simple or complex genomics. Tumors with complex genomics can have aneuploidy and copy number gains and losses, which hampers the detection of early, initiating events in tumorigenesis. Often, no benign precursors are known, which is why good models are essential. The mesenchymal stem cell (MSC) is the presumed cell of origin of sarcoma. In this study, MSCs of murine and canine origin are used as a model to identify driver events for sarcomas with complex genomic alterations as they transform spontaneously after long-term culture. All transformed murine but not canine MSCs formed sarcomas after subcutaneous injection in mice. Using whole genome sequencing, spontaneously transformed murine and canine MSCs displayed a complex karyotype with aneuploidy, point mutations, structural variants, inter-chromosomal translocations, and copy number gains and losses. Cross-species analysis revealed that point mutations in Tp53/Trp53 are common in transformed murine and canine MSCs. Murine MSCs with a cre-recombinase induced deletion of exon 2-10 of Trp53 transformed earlier compared to wild-type murine MSCs, confirming the contribution of loss of p53 to spontaneous transformation. Our comparative approach using transformed murine and canine MSCs points to a crucial role for p53 loss in the formation of sarcomas with complex genomics. Show less
Helm, D. van der; Barnhoorn, M.C.; Jonge-Muller, E.S.M. de; Molendijk, I.; Hawinkels, L.J.A.C.; Coenraad, M.J.; ... ; Verspaget, H.W. 2019
In experimental animals and in patients with pulmonary arterial hypertension (PAH), a wide spectrum of structural and functional conditions is known that may be responsible for the switch of a... Show moreIn experimental animals and in patients with pulmonary arterial hypertension (PAH), a wide spectrum of structural and functional conditions is known that may be responsible for the switch of a state of "compensated" right ventricular (RV) hypertrophy to a state of RV failure. In recent years, therapy with differentiated cells, endothelial progenitor cells, and mesenchymal stem cells has been shown to cause partial or complete reversal of pathological characteristics of PAH. The therapeutic effects of stem or progenitor cell therapy are considered to be (1) paracrine effects from stem or progenitor cells that had engrafted in the myocardium (or elsewhere), by compounds that have anti-inflammatory, antiapoptotic, and proangiogenic actions and (2) unloading effects on the right ventricle due to stem or progenitor cell-induced decrease in pulmonary vascular resistance and decrease in pulmonary artery pressure. Show less
