Insulin-like growth factor-1 (IGF-1) has demonstrated beneficial effects after myocardial infarction (MI). Microencapsulation of IGF-1 could potentially improve results. We aimed to test the effect of an intracoronary (IC) infusion of microencapsulated IGF-1 in a swine acute MI model. For that purpose IC injection of a 10 ml solution of 5 × 10 6 IGF-1 loaded microspheres (MSPs) (n = 8, IGF-1 MSPs), 5 × 10 6 unloaded MSPs (n = 9; MSPs) or saline (n = 7; CON) was performed 48 hours post-MI. Left ventricular ejection fraction (LVEF), indexed ventricular volumes and infarct size (IS) were determined by cardiac magnetic resonance at pre-injection and 10 weeks. Animals were euthanized at 10 weeks, and myocardial fibrosis and vascular density were analysed. End-study LVEF was significantly greater in IGF-1 MSPs compared to MSPs and CON, while ventricular volumes exhibited no significant differences between groups. IS decreased over time in all groups. Collagen volume fraction on the infarct area was significantly reduced in IGF-1 MSPs compared to CON and MSPs. Vascular density analysis of infarct and border zones showed no significant differences between groups. In conclusion, the IC injection of 5 × 10 6 IGF-1 loaded MSPs in a porcine acute MI model successfully improves cardiac function and limits myocardial fibrosis, which could be clinically relevant.Cardiovascular diseases, especially ischemic heart disease, are the leading cause of mortality worldwide accounting for almost 4 million deaths a year in Europe 1,2 . Conventional treatments such as angioplasty and coronary stenting have contributed to reduce early mortality after an acute myocardial infarction (MI) 3 . However, such therapies are only palliative and do not recover the damaged myocardial tissue 4 , so that these diseases still represent a major unmet medical need.In the last two decades stem cell therapy has become a promising treatment option for ischemic cardiomyopathy 5 . As a result, the administration of various cell types has been proposed to address this problem but has shown only moderate improvements in cardiac function 6 .Recently, several studies suggest that the beneficial effect of stem cells does not lie in their multiplication, but in their paracrine actions 7 . Based on this insight, current research directions in regenerative cardiology are moving to a cell-less approach, since it is known now that stem cells are able to secrete combinations of biomolecules that modulate the composition of the damaged cardiac environment contributing to functional tissue repair by stimulating the migration, proliferation and survival of endogenous cardiac progenitor cells (eCSCs) 8,9 , as well as attenuating fibrosis and modulating inflammation 10,11 .Among the secreted substances, there are different cytokines, extracellular vesicles and growth factors including insulin-like growth factor-1 (IGF-1), hepatocyte growth factor (HGF), angiopoietin 2 or vascular endothelial 1

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BackgroundSynovitis is an inflammation-related disease linked to rheumatoid arthritis, osteoarthritis, infections and trauma. This inflammation is accompanied by immune cells infiltration which initiates an inflammatory response causing pain, discomfort and affecting the normal joint function. The treatment of synovitis is based on the administration of anti-inflammatory drugs or biological agents such as platelet rich plasma and mesenchymal stem cells. However, the evaluation and validation of more effective therapies of synovitis requires the establishment of clinically relevant animal models.ResultsIn this study, Large White pigs were pre-immunized to evaluate an antigen-induced synovitis. The immune monitoring of synovial fluids in this model allowed us the identification of IL-12p40 and T cell subsets as immune biomarkers. Moreover, the evolution of synovitis was performed by arthroscopic procedures and kinetic analysis. In summary, this paper describes an animal model of antigen-induced synovitis to be used in the evaluation of anti-inflammatory therapies.ConclusionsThe novelty of this paper lies in the development of a clinically relevant model of synovitis which permits the simultaneous evaluation of synovitis from an immunological, surgical and kinetic point of view.Electronic supplementary materialThe online version of this article (doi:10.1186/s12917-017-1025-4) contains supplementary material, which is available to authorized users.