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Funding Acknowledgements Type of funding sources: Public Institution(s). Main funding source(s): University of Genova Background Reactivation of cardiomyocyte renewal represents a milestone for cardiac regeneration. While broadly active in the early neonatal mammalian myocardium, such mechanism is lost soon after birth, with transition to defective repair. We previously showed that human amniotic fluid stem cells (hAFS) possess cardioprotective and cardioactive paracrine potential in a preclinical adult mouse model of myocardial infarction (MI)1, by sustaining cardiomyocyte cell cycle re-entry up to DNA duplication. Purpose Here we analyse whether hAFS secretome formulations, namely hAFS-conditioned medium (hAFS-CM) over extracellular vesicles (hAFS-EVs) separated from that, can enhance cardiomyocyte renewal in vitro and in vivo. Methods hAFS were obtained by leftover samples of prenatal screening amniocentesis and primed under 1% O2 preconditioning to enrich hAFS-CM and hAFS-EVs with cardioactive factors. hAFS-EVs were concentrated from hAFS-CM by serial ultracentrifugation. hAFS-EVs were profiled by electron microscopy, nanoparticle tracking analysis, proteomics and RNA sequencing (RNAseq). Neonatal mouse ventricular cardiomyocytes (mNVCM) were enzymatically isolated from R26pFUCCI2 mice with fluorescent tagging of cell-cycle by nuclear signal (G1-phase by Cdt1-mCherry; S-G2-M-phases by Geminin-mVenus1)2. mNVCM were stimulated by hAFS-CM or hAFS-EVs to identify the most promising formulation for further analysis in a R26pFUCCI2 4-day-old MI mouse model via intra-peritoneal delivery, according to principles of laboratory animal care and in compliance with authorization from the Italian Ministry of Health. Results hAFS-EVs sustained R26pFUCCI2 mNVCM transition from S- to M-phase by 2.1-fold (*p Conclusions Our current findings suggest that EVs secreted by developmentally juvenile hAFS may be endowed with relevant potential to support cardiomyocyte renewal for future paracrine therapy in regenerative medicine with putative molecular candidate(s) of action in their cargo content including Agrin and non-coding miRNAs.

Introduction Renal transplantation is the best treatment for end-stage renal disease. In the last years, we have seen improvements in immunosuppressive treatment, which have allowed patients to experience a better quality of life and graft survival. Nevertheless, surgical complications remain important problems that increase morbidity, mortality, costs, and hospitalization. Our purpose was to evaluate surgical complications among a large series of 2000 renal transplantations. Patients and Methods We retrospectively analyzed all surgical complications among 2000 renal transplants performed between June 1980 and March 2010 in our department. Results Among 318 (15.9%) surgical complications, 4.8% of patients had urologic problems. Ureteral stenosis and fistula, stent obstruction, and ureteral necrosis occurred in 2.7%, 1.8%, 0.1%, and 0.2% of patients, respectively. Vascular complications reported in 2.7% of patients included arterial or venous thrombosis (1.0% or 0.4%), both arterial and venous thrombosis (0.1%), renal infarction (0.1%), renal artery aneurysm (0.1%) as well as arterial stenosis (0.5%), kinking (0.4%), or dissection (0.1%). Other complications, not specifically related with transplantation surgery, occurred in 4.4% of patients. Conclusion Renal transplantation is a safe surgery by experienced teams. Our rates of surgical complications were within those reported by other series. A meticulous surgical technique is mandatory to prevent them. Prompt diagnosis and management are required to prevent graft damage and patient morbidity.