Human induced mesenchymal stem cells display increased sensitivity to matrix stiffness.

The clinical translation of mesenchymal stem cells (MSCs) is limited by population heterogeneity and inconsistent responses to engineered signals. Specifically, the extent in which MSCs respond to mechanical cues varies significantly across MSC lines. Although induced pluripotent stem cells (iPSCs) have recently emerged as a novel cell source for creating highly homogeneous MSC (iMSC) lines, cellular mechanosensing of iMSCs on engineered materials with defined mechanics is not well understood. Here, we tested the mechanosensing properties of three human iMSC lines derived from iPSCs generated using a fully automated platform. Stiffness-driven changes in morphology were comparable between MSCs and iMSCs cultured atop hydrogels of different stiffness. However, contrary to tissue derived MSCs, no significant changes in iMSC morphology were observed between iMSC lines atop different stiffness hydrogels, demonstrating a consistent response to mechanical signals. Further, stiffness-driven changes in mechanosensitive biomarkers were more pronounced in iMSCs than MSCs, which shows that iMSCs are more adaptive and responsive to mechanical cues than MSCs. This study reports that iMSCs are a promising stem cell source for basic and applied research due to their homogeneity and high sensitivity to engineered mechanical signals

Paradoxical Effect of Nonalcoholic Red Wine Polyphenol Extract, Provinols™, in the Regulation of Cyclooxygenases in Vessels from Zucker Fatty Rats (fa/fa)

The aim of this work was to study the vascular effects of dietary supplementation of a nonalcoholic red wine polyphenol extract, Provinols, in Zucker fatty (ZF) obese rats. ZF or lean rats received diet supplemented or not with Provinols for 8 weeks. Vasoconstriction in response to phenylephrine (Phe) was then assessed in small mesenteric arteries (SMA) and the aorta with emphasis on the contribution of cyclooxygenases (COX). Although no difference in vasoconstriction was observed between ZF and lean rats both in SMA and the aorta, Provinols affected the contribution of COX-derived vasoconstrictor agents. The nonselective COX inhibitor, indomethacin, reduced vasoconstriction in vessels from both groups; however, lower efficacy was observed in Provinols-treated rats. This was associated with a reduction in thromboxane-A2 and 8-isoprostane release. The selective COX-2 inhibitor, NS398, reduced to the same extent vasoconstriction in aortas from ZF and Provinols-treated ZF rats. However, NS398 reduced response to Phe only in SMA from ZF rats. This was associated with a reduction in 8-isoprostane and prostaglandin-E release. Paradoxically, Provinols decreased COX-2 expression in the aorta, while it increased its expression in SMA. We provide here evidence of a subtle and paradoxical regulation of COX pathway by Provinols vessels from obese rats to maintain vascular tone within a physiological range

Microparticles from patients with metabolic syndrome induce vascular hypo-reactivity via Fas/Fas-ligand pathway in mice

Peer reviewedPublisher PD

Contributions à l'optimisation du potentiel ostéogène de cellules souches mésenchymateuses humaines associées à une matrice de carbonate de calcium (études in vitro et in vivo)

PARIS7-Bibliothèque centrale (751132105) / SudocSudocFranceF

Bioreactor Systems for Human Bone Tissue Engineering

Critical size skeletal defects resulting from trauma and pathological disorders still remain a major clinical problem worldwide. Bone engineering aims at generating unlimited amounts of viable tissue substitutes by interfacing osteocompetent cells of different origin and developmental stage with compliant biomaterial scaffolds, and culture the cell/scaffold constructs under proper culture conditions in bioreactor systems. Bioreactors help supporting efficient nutrition of cultured cells and allow the controlled provision of biochemical and biophysical stimuli required for functional regeneration and production of clinically relevant bone grafts. In this review, the authors report the advances in the development of bone tissue substitutes using human cells and bioreactor systems. Principal types of bioreactors are reviewed, including rotating wall vessels, spinner flasks, direct and indirect flow perfusion bioreactors, as well as compression systems. Specifically, the review deals with: (i) key elements of bioreactor design; (ii) range of values of stress imparted to cells and physiological relevance; (iii) maximal volume of engineered bone substitutes cultured in different bioreactors; and (iv) experimental outcomes and perspectives for future clinical translation

Bioreactor Systems for Human Bone Tissue Engineering

Critical size skeletal defects resulting from trauma and pathological disorders still remain a major clinical problem worldwide. Bone engineering aims at generating unlimited amounts of viable tissue substitutes by interfacing osteocompetent cells of different origin and developmental stage with compliant biomaterial scaffolds, and culture the cell/scaffold constructs under proper culture conditions in bioreactor systems. Bioreactors help supporting efficient nutrition of cultured cells and allow the controlled provision of biochemical and biophysical stimuli required for functional regeneration and production of clinically relevant bone grafts. In this review, the authors report the advances in the development of bone tissue substitutes using human cells and bioreactor systems. Principal types of bioreactors are reviewed, including rotating wall vessels, spinner flasks, direct and indirect flow perfusion bioreactors, as well as compression systems. Specifically, the review deals with: (i) key elements of bioreactor design; (ii) range of values of stress imparted to cells and physiological relevance; (iii) maximal volume of engineered bone substitutes cultured in different bioreactors; and (iv) experimental outcomes and perspectives for future clinical translation

GMP-compatible and xeno-free cultivation of mesenchymal progenitors derived from human-induced pluripotent stem cells

Abstract Background Human mesenchymal stem cells are a strong candidate for cell therapies owing to their regenerative potential, paracrine regulatory effects, and immunomodulatory activity. Yet, their scarcity, limited expansion potential, and age-associated functional decline restrict the ability to consistently manufacture large numbers of safe and therapeutically effective mesenchymal stem cells for routine clinical applications. To overcome these limitations and advance stem cell treatments using mesenchymal stem cells, researchers have recently derived mesenchymal progenitors from human-induced pluripotent stem cells. Human-induced pluripotent stem cell-derived progenitors resemble adult mesenchymal stem cells in morphology, global gene expression, surface antigen profile, and multi-differentiation potential, but unlike adult mesenchymal stem cells, it can be produced in large numbers for every patient. For therapeutic applications, however, human-induced pluripotent stem cell-derived progenitors must be produced without animal-derived components (xeno-free) and in accordance with Good Manufacturing Practice guidelines. Methods In the present study we investigate the effects of expanding mesodermal progenitor cells derived from two human-induced pluripotent stem cell lines in xeno-free medium supplemented with human platelet lysates and in a commercial high-performance Good Manufacturing Practice-compatible medium (Unison Medium). Results The results show that long-term culture in xeno-free and Good Manufacturing Practice-compatible media somewhat affects the morphology, expansion potential, gene expression, and cytokine profile of human-induced pluripotent stem cell-derived progenitors but supports cell viability and maintenance of a mesenchymal phenotype equally well as medium supplemented with fetal bovine serum. Conclusions The findings support the potential to manufacture large numbers of clinical-grade human-induced pluripotent stem cell-derived mesenchymal progenitors for applications in personalized regenerative medicine. Graphical abstrac

A biomimetic engineered bone platform for advanced testing of prosthetic implants

Existing methods for testing prosthetic implants suffer from critical limitations, creating an urgent need for new strategies that facilitate research and development of implants with enhanced osseointegration potential. Herein, we describe a novel, biomimetic, human bone platform for advanced testing of implants in vitro, and demonstrate the scientific validity and predictive value of this approach using an assortment of complementary evaluation methods. We anchored titanium (Ti) and stainless steel (SS) implants into biomimetic scaffolds, seeded with human induced mesenchymal stem cells, to recapitulate the osseointegration process in vitro. We show distinct patterns of gene expression, matrix deposition, and mineralization in response to the two materials, with Ti implants ultimately resulting in stronger integration strength, as seen in other preclinical and clinical studies. Interestingly, RNAseq analysis reveals that the TGF-beta and the FGF2 pathways are overexpressed in response to Ti implants, while the Wnt, BMP, and IGF pathways are overexpressed in response to SS implants. High-resolution imaging shows significantly increased tissue mineralization and calcium deposition at the tissue-implant interface in response to Ti implants, contributing to a twofold increase in pullout strength compared to SS implants. Our technology creates unprecedented research opportunities towards the design of implants and biomaterials that can be personalized, and exhibit enhanced osseointegration potential, with reduced need for animal testing