Cirrhotic Liver Sustains In Situ Regeneration of Acellular Liver Scaffolds after Transplantation into G-CSF-Treated Animals.

Acellular liver scaffolds (ALS) produced by decellularization have been successfully explored for distinct regenerative purposes. To date, it is unknown whether transplanted ALSs are affected by cirrhotic livers, either becoming cirrhotic themselves or instead remaining as a robust template for healthy cell growth after transplantation into cirrhotic rats. Moreover, little is known about the clinical course of recipient cirrhotic livers after ALS transplantation. To address these questions, we transplanted ALSs into cirrhotic rats previously treated with the granulocyte colony-stimulating factor. Here, we report successful cellular engraftment within the transplanted ALSs at 7, 15, and 30 days after transplantation. Recellularization was orchestrated by liver tissue cell activation, resident hepatocytes and bile duct proliferation, and an immune response mediated by the granulocyte components. Furthermore, we showed that transplanted ALSs ensured a pro-regenerative and anti-inflammatory microenvironment, attracted vessels from the host cirrhotic tissue, and promoted progenitor cell recruitment. ALS transplantation induced cirrhotic liver regeneration and extracellular matrix remodeling. Moreover, the transplanted ALS sustained blood circulation and attenuated alterations in the ultrasonographic and biochemical parameters in cirrhotic rats. Taken together, our results confirm that transplanted ALSs are not affected by cirrhotic livers and remain a robust template for healthy cell growth and stimulated cirrhotic liver regeneration.

In Situ Maturated Early-Stage Human-Induced Pluripotent Stem Cell-Derived Cardiomyocytes Improve Cardiac Function by Enhancing Segmental Contraction in Infarcted Rats.

The scant ability of cardiomyocytes to proliferate makes heart regeneration one of the biggest challenges of science. Current therapies do not contemplate heart re-muscularization. In this scenario, stem cell-based approaches have been proposed to overcome this lack of regeneration. We hypothesize that early-stage hiPSC-derived cardiomyocytes (hiPSC-CMs) could enhance the cardiac function of rats after myocardial infarction (MI). Animals were subjected to the permanent occlusion of the left ventricle (LV) anterior descending coronary artery (LAD). Seven days after MI, early-stage hiPSC-CMs were injected intramyocardially. Rats were subjected to echocardiography pre-and post-treatment. Thirty days after the injections were administered, treated rats displayed 6.2% human cardiac grafts, which were characterized molecularly. Left ventricle ejection fraction (LVEF) was improved by 7.8% in cell-injected rats, while placebo controls showed an 18.2% deterioration. Additionally, cell-treated rats displayed a 92% and 56% increase in radial and circumferential strains, respectively. Human cardiac grafts maturate in situ, preserving proliferation with 10% Ki67 and 3% PHH3 positive nuclei. Grafts were perfused by host vasculature with no evidence for immune rejection nor ectopic tissue formations. Our findings support the use of early-stage hiPSC-CMs as an alternative therapy to treat MI. The next steps of preclinical development include efficacy studies in large animals on the path to clinical-grade regenerative therapy targeting human patients.

Isolamento, cultivo e caracterização de células derivadas de cardioesferas de camundongos CD1 / Isolation, culture and characterization of cardiospheres-derived cells from CD1 mice

No Brasil, como em todo o mundo, as doenças cardiovasculares têm sido uma das principais causas de morte. A alta mortalidade e as poucas alternativas terapêuticas para esta doença têm estimulado a investigação no campo das células estaminais. Recentemente, alguns grupos têm mostrado a presença de células-tronco/progenitoras residentes no coração. Estas poderiam ser cultivadas diretamente a partir de tecidos cardíacos produzindo aglomerados esféricos denominados Cardioesferas estas, contém células proliferativas que dão origem, após o plaqueamento, a uma população heterogênea denominada: células derivadas de cardioesferas (CDCs). O objetivo deste estudo foi isolar, cultivar e caracterizar as CDCs de camundongos da linhagem CD1. Para isto, as células primárias foram isoladas a partir de corações de camundongos adultos da linhagem CD1 após a digestão de pequenos fragmentos do órgão em 420U/ml utilizando colagenase tipo II por 20 minutos 37°C. Nas análises por Citometria de Fluxo (FACS) foram observadas baixa expressão das moléculas de CD19 (0,4%), CD45 (0,5%) e CD90 (4,77%), e alta expressão das moléculas CD73 (71,47%), CD105 (25,1%), CD14 (25,17%). Nos ensaios de imunofluorescência foi possível observar a expressão das proteínas no citoplasma dos cardiomiócitos: vimentina, desmina e alfa actina de músculo liso, além da expressão do filamento intermediário nestina. Ao analisar a expansão celular por population doubling time foi observado que as CDCs duplicaram sua população original em cerca de 1,8 dias. Estes resultados sugerem que as CDCs isoladas a partir de camundongos da linhagem CD1, são células que apresentam características de células mesenquimais, constituindo uma população celular a ser testada nos estudos em terapias celulares. Estes resultados, motiva a estabelecer protocolos mais efetivos a fim de investigar possíveis efeitos parácrinos benéficos, bem como o potencial angiogênico e cardiogênico destas células.

In Brazil, as elsewhere in the world, cardiovascular diseases have been a major cause of death. The high mortality and few therapeutic alternatives for this disease have stimulated research in the field of stem cells. Recently, some groups have shown the presence of stem cells residents at heart. These could be grown directly from tissue cardiac producing spherical agglomerates called cardiospheres these contains proliferating cells that give rise after plating, a heterogeneous population named: cells derived from cardiospheres (CDC). Our goal in this study was to isolate and characterize the cultivar CDC CD1 strain of mice. For this purpose, primary cells were isolated from hearts of adult mice of the CD1 strain after digestion of the organ into small fragments using 420U/ml collagenase type II for 20 minutes 37 ° C. In analysis by Flow Cytometry (FACS) were observed low expression of CD19 molecules (0.4%), CD45 (0.5%) and CD90 (4.77%), and high expression of the molecules CD73 (71.47%), CD105 (25.1%), CD14 (25.17%). In the immunofluorescence assays was possible to observe the expression of the proteins in the cytoplasm of cardiomyocytes: vimentin, desmin and smooth muscle alpha actin, and expression of the intermediate filament nestin. By analyzing the cellular expansion team for Population doubling was observed that the original CDC doubled its population in about 1.8 days. These results suggest that CDCs isolated from CD1 mouse strain to be have characteristics of mesenchymal cells, constituting a potential population studied in cellular therapies, motivating us to establish more effective protocols to investigate possible beneficial paracrine effects and their angiogenic and cardiogenic potential.

Bone marrow-derived cell therapy in chagasic cardiac disease: a review of pre-clinical and clinical results.

Chagas disease is caused by a protozoan parasite Trypanosoma cruzi, which infects people through blood sucking insects. It is endemic in Latin America and the disease is being spread to developed countries as a result of the migration of infected individuals. In its chronic stage, Chagas disease can lead to a severe cardiomyopathy for which there is currently no cure. End-stage patients require heart transplantation, thus demanding new therapeutic modalities. Cell-based therapy has been proposed as an alternative for various forms of heart disease. Here we review the experimental evidence that led to the use of bone marrow-derived cells in putative therapy for chronic chagasic cardiomyopathy in animal models and in clinical trials, discussing the reasons for failure of the translation of results from mice to men.

Ecocardiograma de alta resolução e o modelo de infarto do miocárdio em camundongos / High resolution echocardiography and the myocardial infarction model in mice

Objetivo: Avaliação do infarto do miocárdio (IM), induzido por isquemia e reperfusão em camundongos, por meio de análises ecocardiográficas, em equipamento específico para pequenos roedores. Medotologia: Camundongos machos e fêmeas C57BL/6 (oito semanas), pesando entre 20 e 25g, foram submetidos à indução do IM pelo protocolo isquemia e reperfusão (n=19), com um período de isquemia de 90 minutos e comparados a animais não infartados (n=10). Foram realizadas avaliações ecocardiográficas, antes do infarto e 8, 20 e 60 dias após a cirurgia com transdutor de alta resolução (30 MHz) específico para camundongos. Foram avaliados os diâmetros cavitários, fração de encurtamento pelo modo unidimensional e tempo de relaxamento isovolumétrico pelo Doppler, além de fração de ejeção calculada pelo método de Simpson, pelo modo bidimensional. Resultados: já na primeira análise, após o infarto do miocárdio, é possível evidenciar a dilatação do ventrículo esquerdo, em sístole (controle 2,10 +ou menos 0,43) mm versus infartado 2,83+ ou menos 0,46 mm, p<0,001) e diástole (controle 3,26+ ou menos 0,33 mm versus infartado 3,83 + ou menos 0,48 mm, p<0,01) e redução da fração de ejeção pelo método e Simpson (controle 74,63 + ou menos 8,29 versus infartado 62,58 + ou menos 11,62, p<0,05). Além disso, foi observado redução do tempo de relaxamento...