Abstract: The amniotic fluidderived stem cells (AFSC) possess considerable advantageous characteristics including high proliferation potential, easy availability, low immunogenicity and oncogenicity，and accordance with medical ethnics. Moreover, they do not require the sacrifice of human embryos for their isolation and the cells can differentiate into all three kinds of germs. Accordingly，they initiate a new and very promising field in stem cell research and they will be a potential source of stem cells for therapies related to regeneration medicine of cardiovascular diseases. The research about the AFSC utilization in cardiovascular diseases is just started. Though there were some exciting breakthroughs, there still remain many challenges. In the article，we will discuss AFSC characteristics, influence of amniotic fluid harvesting time on stem cells, isolation and purification, emphasizing mainly on the potential of AFSC differentiation into cardiovascular cells, current situation and problems in this field.
Abstract:Objective To observe the expression of calcium-dependent proline-rich tyrosine kinase-2（Pyk2） in myocardium of rheumatic heart disease, the relationship between its role and cardiac fibrosis and clinical significance. Methods The blue myocardium collagen stain were analysed after Masson staining in 30 patients with rheumatic heart disease （RHD group） and 6 normal myocardium specimens （control group）. The contents of hyaluronic acid （HA）, laminin（LN） and type IV collagen（IV-C） were detected by radio-immunity method,and the expressions of Pyk2 protein and messenger ribonucleic acid（mRNA） were explored by immunohistochemistry methods and reverse transcriptase polymerase chain reaction （RT PCR）,then the correlations of these results were statistically analyzed. Results The contents of HA,LN and IV C in RHDgroup increased compared to control group（174.95±76.14μg/L vs. 70.06±15.63μg/L, 153. 86 ± 20. 72μg/L vs. 90.01±14. 11μg/L, 95. 26±7.66μg/L vs. 63. 21±10.62μg/L; P= 0.003, 0. 013, 0. 035）. The Pyk2 absorption and the ratio of Pyk2 mRNA/glyceraldehyde phosphate dehydrogenase （GAPDH） in RHD group were significantly higher than those in control group （0. 325 ± 0. 032 vs. 0.106±0.013, 0.870±0.085 vs. 0.573±0.042; P=0.048, 0.006）.There were positive correlativity between the expression of Pyk2 protein and HA, LN and IV-C （r=0. 611, 0. 743, 0. 829, P〈0. 01）, there were positive correlativity between the expression of Pyk2 mRNA and LN, IV-C （r=0. 794, 0. 766, P〈0.05）. Conclusion Pyk2 may play a key role in the proceeding of cardiac fibrosis in rheumatic heart disease by increasing collagen synthesis in myocardium.