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Impaired wound healing in patients with type 2 diabetes (DM2) is characterized by chronic inflammation, which delays wound closure. Specialized pro-resolving lipid mediators (SPMs) are bioactive molecules produced from essential polyunsaturated fatty acids (PUFAs), principally omega-3 docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). SPMs are potent regulators of inflammation and have been used to suppress chronic inflammation in peripheral artery disease, non-alcoholic fatty liver disease, and central nervous system syndromes. LIPINOVA(R) is a commercially available safe-grade nutritional supplement made from a fractionated marine lipid concentrate derived from anchovy and sardine oil that is rich in SPMs and EPA, as well as DHA precursors. Here, we assessed the effect of LIPINOVA(R) in wound dressing applications. LIPINOVA(R) showed biocompatibility with keratinocytes and fibroblasts, reduced the abundance of pro-inflammatory macrophages (M phi 1), and promoted in vitro wound closure. Daily application of the marine oil to open wounds made by punch biopsy in db/db mice promoted wound closure by accelerating the resolution of inflammation, inducing neoangiogenesis and M phi 1/M phi 2 macrophage polarization. In conclusion, LIPINOVA(R) displays pro-resolutive properties and could be exploited as a therapeutic agent for the treatment of diabetic ulcers.

Cardiovascular diseases (CVD) are the leading cause of death in the developed countries. According to the las report of the European Society of Cardiology, CVD remain the most common cause of death within Europe, accounting for 2.2 million deaths in females and 1.9 million deaths in males. These equate to 47% and 39% of all deaths in females and males, respectively, and almost half of them are caused by Myocardial Infarction (MI). In the last 20 years, in order to overcome the limitations of the conventional treatments, cell therapy, has emerged as a promising therapeutic option for the treatment of MI. In this thesis we have employed Adipose Derived Mesenchymal Stem Cells (ADSC) seeded in a collagen scaffold fabricated under GMP-conditions, to treat the infarcted heart in preclinical MI animal models. First, we assessed the patch safety in rodent models, proving a safe profile of the system, established by tumorigenicity, toxicity and biodistribution studies. Secondly, the collagen scaffold was cellularized with allogeneic ADSC and its immunological effect was analysed both in vitro and in vivo, showing no alloreactive response by the immune cells towards the allogeneic patch. Moreover in vitro, in a human context, the cellularized patch elicited a potent immunomodulatory effect towards lymphocytes by inhibiting their proliferation, phenotypical activation and pro-inflammatory cytokine production. Finally, the functionalization of the collagen membrane with the angiogenic factor SDF-1 was achieved, by the creation of a bilayer collagen scaffold, which confirmed to be biocompatible in vivo and exerted a therapeutic effect when tested in a rat MI model in the shape of cardiac function recovery.

Myocardial infarction (MI) leads to an irreversible loss of cardiac myocytes, which compromises cardiac function. The cellular and molecular mechanisms involved in the ischemic event remain under study, being the cardiac exosomes transfer of non-coding RNAs a key process in this pathology. In this context, a comparative analysis of the exosomal compartment of human cardiac progenitor cells (CPC) was performed in comparison with human bone marrow-mesenchymal stem cells (MSC) and human dermal fibroblasts (HDF). A total of 481 differentially expressed microRNAs (miR) were found, being miR-935 the most differentially expressed in CPC. Analysis of miR-935 in vitro overexpression promoted a positive trend to increment cardiomyocyte survival, in response to oxidative stress. Furthermore, when miR-935 regulation was analyzed in a mouse model of MI disease, miR downregulation was shown five days post-infarct in different cardiac subpopulations. In order to study the role of miR-935 in MI and to achieve an optimal miR-935 overexpression in our mouse model, we developed a robust viral-based method for cardiac-specific miR overexpression. Cardiotropic Serotype 9-Adeno-Associated Virus (AAV9) were used for this purpose and their biodistribution was first determined in mice. Ubiquitous EF1α or the cardiac-specific TnT promoters were combined with Luciferase (Luc) or GFP reporters and administered by intramyocardial or intravenous injection, either in healthy or myocardial-infarcted mice. High transgene expression levels were found in the heart, but not in the liver, of mice receiving AAV-TnT, which was significantly higher after intramyocardial injection regardless of ischemia-induction. On the contrary, high hepatic transgene expression levels were detected with the EF1α-promoter, independently of the administration route and heart damage. Luc expression increased with both promoters in a time-dependent manner, reaching a peak by day 3-7 that was stable for at least 60 days. Moreover, tissue-specific GFP expression was found in cardiomyocytes with the TnT-vector, while minimal cardiac expression was detected with the ubiquitous one. Interestingly, we found that MI greatly increased the transcriptional activity of AAV genomes. Thus, we found AAV9-TnT as a robust and stable vector for cardiac-specific delivery after intramyocardial injection. Finally, the therapeutic potential of this vector in combination with miR-935 was evaluated in a mouse model of myocardial ischemia. Intramyocardial injection of AAV9-TnT-miR935 vector did not significantly improve heart function 60 days post-infarct. However, a slight positive trend in the ejection fraction and a decreased adverse cardiac remodeling are observed, suggesting miR-935 putative cardioprotective role.

Human dermo-epidermal skin equivalents (DE) comprising in vitro expanded autologous keratinocytes and fibroblasts are a good option for massive burn treatment. However, the lengthy expansion time required to obtain sufficient surface to cover an extensive burn together with the challenging surgical procedure limits their clinical use. The integration of DE and biodegradable scaffolds has been proposed in an effort to enhance their mechanical properties. Here, it is shown that poly(hydroxybutyrate) electrospun scaffolds (PHB) present good biocompatibility both in vitro and in vivo and are superior to poly-epsilon-caprolactone electrospun scaffolds as a substrate for skin reconstruction. Implantation of PHB scaffolds in healthy rats polarized macrophages to an M2-type that promoted constructive in vivo remodelling. Moreover, implantation of DE-PHB composites in a NOD/SCID mouse xenograft model resulted in engraftment accompanied by an increase in angiogenesis that favoured the survival of the human graft. Thus, PHB scaffolds are an attractive substrate for further exploration in skin reconstruction procedures, probably due in part to their greater angiogenic and M2 macrophage polarization properties. Copyright (c) 2017 John Wiley & Sons, Ltd.

Principal limitation for generating cardiomyocytes from stem cells is that differentiated cells generally present electrophysiological immature and heterogeneous phenotype, which may hamper their in vitro and in vivo application. The purpose of this study was to examine the effect of NRG-1b and DMSO in the in vitro generation of mature working-type cardiomyocytes from induced pluripotent stem (iPS) cells and to determine their contribution to the cardiac tissue regeneration after acute myocardial infarction (AMI). iPS cells were derived from α-MHC-GFP mice fibroblasts and were in vitro differentiated towards cardiomyocytes by DMSO and/or NRG-1b treatment. iPS cardiac specification and maturation was analyzed by Q-RT-PCR, immunofluorescence, electronic microscopy and patch-clamp techniques. The iPS-derived cardiomyocytes (n=15) or culture-medium as control (n=13) were injected into the peri-infarct region of mice hearts following coronary artery ligation. Echocardiography and histology assessments were performed from 1-8 weeks post-transplantation. iPS cells showed early and robust in vitro cardiogenesis with cardiac gene and protein expression in all cases. Electrophysiological studies demonstrated a more mature ventricular-like cardiac phenotype when cells were treated with NRG-1b and DMSO than with DMSO-treatment alone. In vivo studies in the AMI mouse model demonstrated that iPS-derived CMs preserved cardiac function and induced a positive heart tissue remodeling. Moreover, iPS-CMs engrafted and electromechanically couple into the heart tissue. The combination of NRG-1b and DMSO induced iPS cells differentiation towards mature ventricular-like cardiac cells which, when transplanted in a model of AMI, contributed to preserve the cardiac function and tissue viability.

Substrate stiffness, biochemical composition, and matrix topography deeply influence cell behavior, guiding motility, proliferation, and differentiation responses. The aim of this work was to determine the effect that the stiffness and protein composition of the underlying substrate has on the differentiation of induced pluripotent stem (iPS) cells and the potential synergy with specific soluble cues. With that purpose, murine iPS-derived embryoid bodies (iPS-EBs) were seeded on fibronectin- or collagen I-coated polyacrylamide (pAA) gels of tunable stiffness (0.6, 14, and 50 kPa) in the presence of basal medium; tissue culture polystyrene plates were employed as control. Specification of iPS cells toward the three germ layers was analyzed, detecting an increase of tissue-specific gene markers in the pAA matrices. Interestingly, soft matrix (0.6 kPa) coated with fibronectin favored differentiation toward cardiac and neural lineages and, in the case of neural differentiation, the effect was potentiated by the addition of specific soluble factors. The generation of mature astrocytes, neural cells, and cardiomyocytes was further proven by immunofluorescence and transmission electron microscopy. In summary, this work emphasizes the importance of using biomimetic matrices to accomplish a more specific and mature differentiation of stem cells for future therapeutic applications.

Los objetivos del presente trabajo han sido los siguientes: 1. Aislar y caracterizar la población de células madre derivadas del tejido adiposo (ADSC), a partir de grasa de rata Sprague‐Dawley. 2. Caracterizar el comportamiento biológico y mecánico de distintos tipos de membranas de colágeno y determinar su biocompatibilidad in vivo. 3. Analizar de forma comparativa, el potencial terapéutico de las ADSC en el corazón, al ser trasplantadas como parche celular (mediante su previa adhesión a una membrana de colágeno) o inyectadas sin soporte, en un modelo de infarto crónico de miocardio en rata. 4. Determinar los mecanismos implicados en la posible acción terapéutica de las membranas celularizadas con ADSC.

Since the discovery of the Vascular Endothelial Growth Factor (VEGF) and its leading role in the angiogenic process, this has been seen as a promising molecule for promoting neovascularization in the infarcted heart. However, even though several clinical trials were initiated, no therapeutic effects were observed, due in part to the short half life of this factor when administered directly to the tissue. In this context, drug delivery systems appear to offer a promising strategy to overcome limitations in clinical trials of VEGF. The aim of this paper is to review the principal drug delivery systems that have been developed to administer VEGF in cardiovascular disease. Studies published in the last 5 years are reviewed and the main features of these systems are explained. The tissue engineering concept is introduced as a therapeutic alternative that holds promise for the near future.

The clinical trials performed in patients with myocardial infarction and based on the intravascular injection of growth factors have failed, owing, among other reasons, to protein instability after injection. The hypothesis of this research is that a local controlled release of the growth factors by using a polymeric delivery system could protect the growth factors from degradation and stimulate cardiac repair. To test this, the following specific objectives were proposed: 1. Design, development and physico-chemical characterization of PLGA microparticles intended for intramyocardial administration. In vivo compatibility assessment of the developed microparticles with the cardiac tissue. 2. Development of VEGF165 loaded PLGA microparticles, in vitro characterization and assessment of the potential benefit of the VEGF165-microparticles in an acute rat myocardial ischemia– reperfusion model. 3. Development of FGF-1 and NRG-1 into PLGA microparticles, in vitro characterization and evaluation of the therapeutic potential of FGF-1 and/or NRG-1 cytokines delivered from PLGA microparticles in a rat myocardial infarction model.

BACKGROUND: Pemphigus vulgaris (PV) is an autoimmune disease characterized by mucocutaneous intraepithelial blisters and pathogenic autoantibodies against desmoglein 3. The mechanism of blister formation in pemphigus has not been defined; however, in vitro data suggest a role for activation of intracellular signalling cascades. OBJECTIVES: To investigate the contribution of these signalling pathways to the mechanism of PV IgG-induced acantholysis in vivo. METHODS: We used the passive transfer mouse model. Mice were injected with IgG fractions of sera from a patient with PV, with or without pretreatment with inhibitors of proteins that mediate intracellular signalling cascades. RESULTS: Inhibitors of tyrosine kinases, phospholipase C, calmodulin and the serine/threonine kinase protein kinase C prevented PV IgG-induced acantholysis in vivo. CONCLUSIONS: These observations strongly support the role of intracellular signalling cascades in the molecular mechanism of PV IgG-induced acantholysis.