BackgroundAutologous bone marrow–derived mesenchymal stromal cell (MSC) therapy and withdrawal of calcineurin inhibitors (CNIs) has been shown to improve systemic blood pressure control and left ve...Show moreBackgroundAutologous bone marrow–derived mesenchymal stromal cell (MSC) therapy and withdrawal of calcineurin inhibitors (CNIs) has been shown to improve systemic blood pressure control and left ventricular hypertrophy regression in kidney transplant recipients. In the current subanalysis, we aimed to evaluate the impact of this novel immunosuppressive regimen on the longitudinal changes of left atrial (LA) structure and function after kidney transplantation.MethodsKidney transplant recipients randomized to MSC therapy—infused at weeks 6 and 7 after transplantation, with complete discontinuation at week 8 of tacrolimus (MSC group)—or standard tacrolimus dose (control group) were evaluated with transthoracic echocardiography at weeks 4 and 24 after kidney transplantation. The changes in echocardiographic parameters were compared between the randomization arms using an analysis of covariance model adjusted for baseline variable.ResultsFifty-four participants (MSC therapy = 27; tacrolimus therapy = 27) were included. There was no significant interaction between the allocated treatment and the changes of indexed maximal LA volume (LAVImax) over the study period. Conversely, between 4 and 24 weeks post-transplantation, an increase in indexed minimal LA volume (LAVImin) was observed in control subjects, while it remained unchanged in the MSC group, leading to a significant difference between groups (P = .021). Additionally, patients treated with MSC therapy showed a benefit in LA function, assessed by a significant interaction between changes in LA emptying fraction and LA reservoir strain and the randomization arm (P = .012 and P = .027, respectively).ConclusionsThe combination of MSC therapy and CNIs withdrawal prevents progressive LA dilation and dysfunction in the first 6 months after kidney transplantation. LAVImin and LA reservoir strain may be more sensitive markers of LA reverse remodeling, compared with LAVImax. Show less
Vermeulen, S.; Roumans, N.; Honig, F.; Carlier, A.; Hebels, D.G.A.J.; Eren, A.D.; ... ; Boer, J. de 2020
We previously found that surface topographies induce the expression of the Scxa gene, encoding Scleraxis in tenocytes. Because Scxa is a TGF-beta responsive gene, we investigated the link between... Show moreWe previously found that surface topographies induce the expression of the Scxa gene, encoding Scleraxis in tenocytes. Because Scxa is a TGF-beta responsive gene, we investigated the link between mechanotransduction and TGF-beta signaling. We discovered that mesenchymal stem cells exposed to both micro-topographies and TGF-beta 2 display synergistic induction of SMAD phosphorylation and transcription of the TGF-beta target genes SCX, alpha-SMA, and SOX9. Pharmacological perturbations revealed that Rho/ROCK/SRF signaling is required for this synergistic response. We further found an activation of the early response genes SRF and EGR1 during the early adaptation phase on micro-topographies, which coincided with higher expression of the TGF-beta type II receptor gene. Of interest, PKC activators Prostratin and Ingenol-3, known for inducing actin reorganization and activation of serum response elements, were able to mimic the topography-induced TGF-beta response. These findings provide novel insights into the convergence of mechanobiology and TGF-beta signaling, which can lead to improved culture protocols and therapeutic applications. Show less
Mollazadeh, S.; Bazzaz, B.S.F.; Neshati, V.; Vries, A.A.F. de; Naderi-Meshkin, H.; Mojarad, M.; ... ; Kerachian, M.A. 2019
BackgroundMesenchymal stem cells (MSCs) are attractive choices in regenerative medicine and can be genetically modified to obtain better results in therapeutics. Bone development and metabolism are... Show moreBackgroundMesenchymal stem cells (MSCs) are attractive choices in regenerative medicine and can be genetically modified to obtain better results in therapeutics. Bone development and metabolism are controlled by various factors including microRNAs (miRs) interference, which are small non-coding endogenous RNAs.MethodsIn the current study, the effects of forced miR-148b expression was evaluated on osteogenic activity. Human bone marrow-derived mesenchymal stem cells (BM-MSCs) were transduced with bicistronic lentiviral vector encoding hsa-miR-148b-3p or -5p and the enhanced green fluorescent protein. Fourteen days post-transduction, immunostaining as well as Western blotting were used to analyze osteogenesis.ResultsOverexpression of miR-148b-3p increased the osteogenic differentiation of human BM-MSCs as demonstrated by anenhancement of mineralized nodular formation and an increase in the levels of osteoblastic differentiation biomarkers, alkaline phosphatase and collagen type I.ConclusionsSince lentivirally overexpressed miR-148b-3p increased osteogenic differentiation capability of BM-MSCs, this miR could be applied as a therapeutic modulator to optimize bone function. Show less
Taj, S.H.; Blon, D. le; Hoornaert, C.; Daans, J.; Quarta, A.; Praet, J.; ... ; Hoehn, M. 2018
In this thesis molecular and environmental cues in cardiac differentiation of mesenchymal stem cells were investigated. The main conclusions were that the cardiac differentiation potential of human... Show moreIn this thesis molecular and environmental cues in cardiac differentiation of mesenchymal stem cells were investigated. The main conclusions were that the cardiac differentiation potential of human mesenchymal stem cells negatively correlates with donor age. This in its own shows a negative relationship with connexin 43 levels in these cells. However, a causal relationship between connexin 43 expression levels and cardiomyogenic differentiation potential only exists for human mesenchymal stem cells from prenatal sources, i.e. while knockdown of connexin 43 expression in fetal human mesenchymal stem cells inhibits their ability to differentiate into cardiomyocytes, connexin 43 overexpression in adult human mesenchymal stem cells does not endow them with cardiomyogenic differentiation capacity. In addition, co-culture studies showed that the alignment and distribution of mesenchymal stem cells affect their electrical integration into host myocardium and are major determinants of their pro-arrhythmic risk. The mechanisms underlying the pro-arrhythmic effects of hMSCs are to some extent comparable to those of cardiac myofibroblasts, cells that are found in fibrotic myocardium Show less
The application of MSC as therapeutic agent to treat a variety of immune related diseases is currently under investigation in preclinical and clinical studies. Although promising results have been... Show moreThe application of MSC as therapeutic agent to treat a variety of immune related diseases is currently under investigation in preclinical and clinical studies. Although promising results have been reported, more insight in the basic MSC biology and in the mechanisms by which MSC modulate the immune system are necessary to optimize the safe and effective application of MSC in the clinic. This thesis describes our contributions to the understanding of the immunomodulatory mechanisms of MSC. We also investigated some translational aspects of MSC therapy, aiming at selecting the preferred tissue source for clinical application. The work supports the role of MSC as powerful modulators of the innate and adaptive immune response. Immune suppression by MSC through modulation of monocytes and macrophages sheds a new light on the possible mechanism of therapeutic application of MSC for immunomodulatory purposes and the invo lvement of type 2 macrophages in tissue repair might link the immunomodulatory properties of MSC to the possibly advantageous effects of MSC for tissue regeneration. The fundamental studies on the immunomodulatory effects of MSC may provide valuable knowledge on how to proceed with applying MSC as a therapy in immune related diseases. Show less
Estrogen is known to play an important role in longitudinal bone growth and growth plate maturation, but the mechanism by which estrogens exert their effect is not fully understood. In this thesis... Show moreEstrogen is known to play an important role in longitudinal bone growth and growth plate maturation, but the mechanism by which estrogens exert their effect is not fully understood. In this thesis this role is further explored. Chapter 1 contains a general introduction to longitudinal bone growth and the regulation of the growth plate in respect to relevant topics further studied in this thesis. Estrogen can act through a genomic or a nongenomic pathway. Both pathways are explored in rats at the onset of maturation in chapter 2. Estrogen stimulates VEGF expression in uterus and bone, which is an important growth factor for chondrocyte differentiation and chondrocytes survival in the growth plate. In chapter 3 the effect of estrogen on VEGF expression in the growth plate was studied in the rat and human growth plate. Another effect of estrogen is that it accelerates growth plate senescence. Senescence is one of the postulated intrinsic mechanisms by which the growth plate matures and finally fuses. In chapter 4 we investigated senescence in relation to proliferation, by investigating a cell cycle inhibitor p27Kip1. In animal models, catch-up growth is suggested to be caused by delayed growth plate senescence. In chapter 5 this hypothesis was further tested in humans. With puberty estrogen levels increase, the growth plate matures and at the end growth ceases with epiphyseal fusion through mechanisms not yet completely understood. In order to further explore growth plate maturation we subjected two growth plate tissues of the same patient, but with one year and one pubertal Tanner stage in between, to microarray analyses. Gene expression patterns and transcription factor binding sides in relation to pubertal maturation were studied in a longitudinal study within this single patient in chapter 6. In addition, we collected extra prepubertal and pubertal growth plate tissues and studied these samples with microarray techniques as well in chapter 7. In chapter 8 the process of epiphyseal fusion and apoptosis was studied in human growth plates. Animal models are frequently used but not fully representative for the human growth plate. Therefore we investigated a promising human in vitro model with multipotent mesenchymal stem cells (MSCs) that can differentiate into chondrocytes. MSCs can be isolated from various tissues. In chapter 9 we investigated the chondrogenic potential of MSCs from different origins and in chapter 10 we compared this model with the epiphyseal growth plate by analyzing gene expression patterns and pathways with micro-array analyses. Chapter 11 contains general conclusions and a discussion regarding the results. Show less
