Amniotic Fluid Derived Stem Cells with a Renal Progenitor Phenotype Inhibit Interstitial Fibrosis in Renal Ischemia and Reperfusion Injury in Rats.

OBJECTIVES: Mesenchymal stem cells derived from human amniotic fluid (hAFSCs) are a promising source for cellular therapy, especially for renal disorders, as a subpopulation is derived from the fetal urinary tract. The purpose of this study was to evaluate if hAFSCs with a renal progenitor phenotype demonstrate a nephroprotective effect in acute ischemia reperfusion (I/R) model and prevent late stage fibrosis. METHODS: A total of 45 male 12-wk-old Wistar rats were divided into three equal groups;: rats subjected to I/R injury and treated with Chang Medium, rats subjected to I/R injury and treated with hAFSCs and sham-operated animals. In the first part of this study, hAFSCs that highly expressed CD24, CD117, SIX2 and PAX2 were isolated and characterized. In the second part, renal I/R injury was induced in male rats and cellular treatment was performed 6 hours later via arterial injection. Functional and histological analyses were performed 24 hours, 48 hours and 2 months after treatment using serum creatinine, urine protein to creatinine ratio, inflammatory and regeneration markers and histomorphometric analysis of the kidney. Statistical analysis was performed by analysis of variance followed by the Tukey's test for multiple comparisons or by nonparametric Kruskal-Wallis followed by Dunn. Statistical significance level was defined as p <0.05. RESULTS: hAFSCs treatment resulted in significantly reduced serum creatinine level at 24 hours, less tubular necrosis, less hyaline cast formation, higher proliferation index, less inflammatory cell infiltration and less myofibroblasts at 48 h. The treated group had less fibrosis and proteinuria at 2 months after injury. CONCLUSION: hAFSCs contain a renal progenitor cell subpopulation that has a nephroprotective effect when delivered intra-arterially in rats with renal I/R injury, and reduces interstitial fibrosis on long term follow-up.

Restauração do diafragma de cão com centro tendinoso de ovino conservado em glicerina a 98%

Foram utilizados 12 cães, adultos, sem raça definida, pesando entre 13 e 21 kg com o objetivo de estudar o processo cicatricialde um segmento de centro tendinoso de ovino conservado em glicerina a 98% no reparo de defeito no músculo diafragma decão. Foi removido um segmento na porção muscular do diafragma, de dimensões 6,0 x 4,5cm, para posterior implantação decentro tendinoso heterólogo, mediante toracotomia no 1 Oº espaço intercostal direito. Seis cães foram ob~ervados por umperíodo de 30 dias de pós-operatório e, o restante, por 60 dias, quando foram reoperados para observação macroscópica ecoleta de amostras para avaliação histológica. Foi verificada, aos 30 dias, substituição parcial e, aos 60, substituição total doenxerto por tecido fibrovascular, permitindo o restabelecimento completo do diafragma por meio de firme inserção.Macroscopicamente foi notado, na cavidade torácica, maior índice de aderência com a pleura parietal e, na cavidade abdominal,com o fígado, porém, sem comprometimento clínico. O segmento de centro tendinoso de ovino conservado em soluçãode glicerina a 98%, em temperatura ambiente, pode ser utilizado para reparo de defeitos diafragmáticos, uma vez que suportao gradiente de pressão no diafragma e é substituído por tecido cicatricial, sem apresentar sinais clínicos e histológicos derejeição.