In vivo experience with natural scaffolds for myocardial infarction : the times they are a-changin'

Altres ajuts: La Marató de TV3 (12/2232)Treating a myocardial infarction (MI), the most frequent cause of death worldwide, remains one of the most exciting medical challenges in the 21st century. Cardiac tissue engineering, a novel emerging treatment, involves the use of therapeutic cells supported by a scaffold for regenerating the infarcted area. It is essential to select the appropriate scaffold material; the ideal one should provide a suitable cellular microenvironment, mimic the native myocardium, and allow mechanical and electrical coupling with host tissues. Among available scaffold materials, natural scaffolds are preferable for achieving these purposes because they possess myocardial extracellular matrix properties and structures. Here, we review several natural scaffolds for applications in MI management, with a focus on pre-clinical studies and clinical trials performed to date. We also evaluate scaffolds combined with different cell types and proteins for their ability to promote improved heart function, contractility and neovascularization, and attenuate adverse ventricular remodeling. Although further refinement is necessary in the coming years, promising results indicate that natural scaffolds may be a valuable translational therapeutic option with clinical impact in MI repair

Transitioning From Preclinical Evidence to Advanced Therapy Medicinal Product: A Spanish Experience

A systematic and ordered product development program, in compliance with current quality and regulatory standards, increases the likelihood of yielding a successful advanced therapy medicinal product (ATMP) for clinical use as safe and effective therapy. As this is a novel field, little accurate information is available regarding the steps to be followed, and the information to be produced to support the development and use of an ATMP. Notably, successful clinical translation can be somewhat cumbersome for academic researchers. In this article, we have provided a summary of the available information, supported by our experience in Spain throughout the development of an ATMP for myocardial infarction, from the pre-clinical stage to phase I clinical trial approval

Clinical translation of mesenchymal stromal cell extracellular vesicles : Considerations on scientific rationale and production requisites

The present paper is a commentary to 'Identification and characterization of hADSC - derived exosome proteins from different isolation methods ' (Huang et al. 2021; ). Given the enthusiasm for the potential of mesenchymal stromal cell-derived extracellular vesicles (MSC-EVs), some considerations deserve attention as they move through successive stages of research and application into humans. We herein remark the prerequisite of generating that evidence ensuring a high consistency in safety, composition and biological activity of the intended MSC-EV preparations, and the suitability of disparate isolation techniques to produce efficacious EV preparations and fulfil requirements for standardized clinical-grade biomanufacturing

Noninvasive assessment of an engineered bioactive graft in myocardial infarction: impact on cardiac function and scar healing

Cardiac tissue engineering, which combines cells and biomaterials, is promising for limiting the sequelae of myocardial infarction (MI). We assessed myocardial function and scar evolution after implanting an engineered bioactive impedance graft (EBIG) in a swine MI model. The EBIG comprises a scaffold of decellularized human pericardium, green fluorescent protein-labeled porcine adipose tissue-derived progenitor cells (pATPCs), and a customized-design electrical impedance spectroscopy (EIS) monitoring system. Cardiac function was evaluated noninvasively by using magnetic resonance imaging (MRI). Scar healing was evaluated by using the EIS system within the implanted graft. Additionally, infarct size, fibrosis, and inflammation were explored by histopathology. Upon sacrifice 1 month after the intervention, MRI detected a significant improvement in left ventricular ejection fraction (7.5%64.9% vs. 1.4%63.7%; p = .038) and stroke volume (11.565.9 ml vs. 364.5 ml; p = .019) in EBIG-treated animals. Noninvasive EIS data analysis showed differences in both impedance magnitude ratio (20.02 6 0.04 per day vs. 20.48 6 0.07 per day; p = .002) and phase angle slope (20.18°60.24° per day vs.23.52°60.84° per day; p = .004) in EBIG compared with control animals. Moreover, in EBIG-treated animals, the infarct size was 48% smaller (3.4%60.6% vs. 6.5%61%; p = .015), less inflammation was found by means of CD25+ lymphocytes (0.65 6 0.12 vs. 1.26 6 0.2; p = .006), and a lower collagen I/III ratio was detected (0.4960.06 vs. 1.6660.5; p = .019). An EBIG composed of acellular pericardium refilled with pATPCs significantly reduced infarct size and improved cardiac function in a preclinical model of MI. Noninvasive EIS monitoring was useful for tracking differential scar healing in EBIG-treated animals, which was confirmed by less inflammation and altered collagen deposit.Peer ReviewedPostprint (published version

Combined administration of mesenchymal stem cells overexpressing IGF-1 and HGF enhances neovascularization but moderately improves cardiac regeneration in a porcine model

(A) Lentiviral vectors used for IGF-1 and HGF forced expression in paMSC. (B) Fluorescence of cultures at distinct viral concentrations after transduction with the pRRL-sin-IGF-1-IRES-GFP vector. Images for paMSC-IGF-1-GFP, 5 days post-transduction, at distinct multiplicity of infection (MOI, 1–50). (C) Cell sorting after paMSC transduction. Four subpopulations resulting from sorting. Top panels, results for a subpopulation cultured at 3 % O2; bottom, transduced paMSC cultured in 20 % O2 conditions. An un-transduced cell population was used as a negative control. Purity of sorted GFP-positive paMSC was 95 % and 91.1 % for cells cultured at 3 % and 20 % O2, respectively. (TIF 447 kb

Mechanisms of action of sacubitril/valsartan on cardiac remodeling : a systems biology approach

Sacubitril/Valsartan, proved superiority over other conventional heart failure management treatments, but its mechanisms of action remains obscure. In this study, we sought to explore the mechanistic details for Sacubitril/Valsartan in heart failure and post-myocardial infarction remodeling, using an in silico, systems biology approach. Myocardial transcriptome obtained in response to myocardial infarction in swine was analyzed to address post-infarction ventricular remodeling. Swine transcriptome hits were mapped to their human equivalents using Reciprocal Best (blast) Hits, Gene Name Correspondence, and InParanoid database. Heart failure remodeling was studied using public data available in gene expression omnibus (accession GSE57345, subseries GSE57338), processed using the GEO2R tool. Using the Therapeutic Performance Mapping System technology, dedicated mathematical models trained to fit a set of molecular criteria, defining both pathologies and including all the information available on Sacubitril/Valsartan, were generated. All relationships incorporated into the biological network were drawn from public resources (including KEGG, REACTOME, INTACT, BIOGRID, and MINT). An artificial neural network analysis revealed that Sacubitril/Valsartan acts synergistically against cardiomyocyte cell death and left ventricular extracellular matrix remodeling via eight principal synergistic nodes. When studying each pathway independently, Valsartan was found to improve cardiac remodeling by inhibiting members of the guanine nucleotide-binding protein family, while Sacubitril attenuated cardiomyocyte cell death, hypertrophy, and impaired myocyte contractility by inhibiting PTEN. The complex molecular mechanisms of action of Sacubitril/Valsartan upon post-myocardial infarction and heart failure cardiac remodeling were delineated using a systems biology approach. Further, this dataset provides pathophysiological rationale for the use of Sacubitril/Valsartan to prevent post-infarct remodeling. The new wonder drug in heart failure management, Sacubitril/Valsartan, rejuvenates the heart by preventing its dilation. Using data from myocardial infarction and heart failure samples, we generated a mathematical model to better understand how Sacubitril/Valsartan modulates pathological heart resize and the combined effect of the drug. Our analysis revealed that Sacubitril/Valsartan mainly acts by blocking both, cell death and the pathological makeover of the outer-membrane of the cardiac cells. These two major processes occur after a heart attack. Most importantly, we discovered a core of 8 proteins that emerge as key players in this process. A better understanding of the mechanism of novel cardiovascular drugs at the most basic level may help decipher future therapies and indications

Silk-reinforced collagen hydrogels with raised multiscale stiffness for mesenchymal cells 3D culture

Type I collagen hydrogels are of high interest in tissue engineering. With the evolution of 3D bioprinting technologies, a high number of collagen-based scaffolds have been reported for the development of 3D cell cultures. A recent proposal was to mix collagen with silk fibroin derived from Bombyx mori silkworm. Nevertheless, due to the difficulties in the preparation and the characteristics of the protein, several problems such as phase separation and collagen denaturation appear during the procedure. Therefore, the common solution is to diminish the concentration of collagen although in that way the most biologically relevant component is reduced. In this study, we present a new, simple, and effective method to develop a collagen-silk hybrid hydrogel with high collagen concentration and with increased stiffness approaching that of natural tissues, which could be of high interest for the development of cardiac patches for myocardial regeneration and for preconditioning of mesenchymal stem cells (MSCs) to improve their therapeutic potential. Sericin in the silk was preserved by using a physical solubilizing procedure that results in a preserved fibrous structure of type I collagen, as shown by ultrastructural imaging. The macro- and micromechanical properties of the hybrid hydrogels measured by tensile stretch and atomic force microscopy, respectively, showed a more than twofold stiffening than the collagen-only hydrogels. Rheological measurements showed improved printability properties for the developed biomaterial. The suitability of the hydrogels for 3D cell culture was assessed by 3D bioprinting bone marrow-derived MSCs cultured within the scaffolds. The result was a biomaterial with improved printability characteristics that better resembled the mechanical properties of natural soft tissues while preserving biocompatibility owing to the high concentration of collagen. Impact statement In this study, we report the development of silk microfiber-reinforced type I collagen hydrogels for 3D bioprinting and cell culture. In contrast with previously reported studies, a novel physical method allowed the preservation of the silk sericin protein. Hydrogels were stable, showed no phase separation between the biomaterials, and they presented improved printability. An increase between two- and threefold of the multiscale stiffness of the scaffolds was achieved with no need of using additional crosslinkers or complex methods, which could be of high relevance for cardiac patches development and for preconditioning mesenchymal stem cells (MSCs) for therapeutic applications. We demonstrate that bone marrow-derived MSCs can be effectively bioprinted and 3D cultured within the stiffened structures.This work was supported in part by the Spanish Ministry of Sciences, Innovation and Universities (DPI2017-83721-P and PGC2018-097323-A-I00) and by the Marie Sklodowska- Curie Action, Innovative Training Networks 2018, EU Grant Agreement no. 812772.Peer ReviewedPostprint (published version

Deep Learning Analyses to Delineate the Molecular Remodeling Process after Myocardial Infarction

Specific proteins and processes have been identified in post-myocardial infarction (MI) pathological remodeling, but a comprehensive understanding of the complete molecular evolution is lacking. We generated microarray data from swine heart biopsies at baseline and 6, 30, and 45 days after infarction to feed machine-learning algorithms. We cross-validated the results using available clinical and experimental information. MI progression was accompanied by the regulation of adipogenesis, fatty acid metabolism, and epithelial-mesenchymal transition. The infarct core region was enriched in processes related to muscle contraction and membrane depolarization. Angiogenesis was among the first morphogenic responses detected as being sustained over time, but other processes suggesting post-ischemic recapitulation of embryogenic processes were also observed. Finally, protein-triggering analysis established the key genes mediating each process at each time point, as well as the complete adverse remodeling response. We modeled the behaviors of these genes, generating a description of the integrative mechanism of action for MI progression. This mechanistic analysis overlapped at different time points; the common pathways between the source proteins and cardiac remodeling involved IGF1R, RAF1, KPCA, JUN, and PTN11 as modulators. Thus, our data delineate a structured and comprehensive picture of the molecular remodeling process, identify new potential biomarkers or therapeutic targets, and establish therapeutic windows during disease progression

Head-to-head comparison of two engineered cardiac grafts for myocardial repair: From scaffold characterization to pre-clinical testing

Cardiac tissue engineering, which combines cells and supportive scaffolds, is an emerging treatment for restoring cardiac function after myocardial infarction (MI), although, the optimal construct remains a challenge. We developed two engineered cardiac grafts, based on decellularized scaffolds from myocardial and pericardial tissues and repopulated them with adipose tissue mesenchymal stem cells (ATMSCs). The structure, macromechanical and micromechanical scaffold properties were preserved upon the decellularization and recellularization processes, except for recellularized myocardium micromechanics that was ∼2-fold stiffer than native tissue and decellularized scaffolds. Proteome characterization of the two acellular matrices showed enrichment of matrisome proteins and major cardiac extracellular matrix components, considerably higher for the recellularized pericardium. Moreover, the pericardial scaffold demonstrated better cell penetrance and retention, as well as a bigger pore size. Both engineered cardiac grafts were further evaluated in pre-clinical MI swine models. Forty days after graft implantation, swine treated with the engineered cardiac grafts showed significant ventricular function recovery. Irrespective of the scaffold origin or cell recolonization, all scaffolds integrated with the underlying myocardium and showed signs of neovascularization and nerve sprouting. Collectively, engineered cardiac grafts -with pericardial or myocardial scaffolds- were effective in restoring cardiac function post-MI, and pericardial scaffolds showed better structural integrity and recolonization capability