Background and Objectives: It was postulated that adriamycin (ADR) induce renal tubulointerstitial injury. Clinicians are faced with a challenge in producing response in renal patients and slowing or halting the evolution towards kidney failure. The present study aimed at investigating the relation between the possible therapeutic effect of human mesenchymal stem cells (HMSCs), isolated from cord blood on tubular renal damage and their distribution by using ADR induced nephrotoxicity as a model in albino rat. Methods and Results: Thirty three male albino rats were divided into control group, ADR group where rats were given single intraperitoneal (IP) injection of 5 mg/kg adriamycin. The rats were sacrificed 10, 20 and 30 days following confirmation of tubular injury. In stem cell therapy group, rats were injected with HMSCs following confirmation of renal injury and sacrificed 10, 20 and 30 days after HMSCs therapy. Kidney sections were exposed to histological, histochemical, immunohistochemical, morphometric and serological studies. In response to SC therapy, vacuolated cytoplasm, dark nuclei, detached epithelial lining and desquamated nuclei were noticed in few collecting tubules (CT). 10, 20 and 30 days following therapy. The mean count of CT showing desquamated nuclei and mean value of serum creatinine revealed significant difference in ADR group. The mean area% of Prussian blue+ve cells and that of CD105 +ve cells measured in subgroup S1 denoted a significant increase compared to subgroups S2 and S3. Conclusions: ADR induced tubulointerstitial damage that regressed in response to cord blood HMSC therapy.

Introduction: Cardiovascular disease is the leading cause of death worldwide. Mesenchymal stem cells (MSCs) could be a promising therapy for treating cardiomyopathy. Aim of Work:To compare the therapeutic effects of MSCs and losartan (LOS) on doxorubicin (DOX) induced cardiomyopathy. Material and Methods: Thirty-nine male albino rats were divided into group I as a control group, group II received DOX 5 mg/kg ip once, group III received DOX as in group II `after 3 weeks LOS was given 30 mg/kg daily by gastric tube for 3 weeks and group IV received DOX as in group and after 3 weeks rats injected by 1ml of Paul Karl Haron (PKH)26 labeled MSCs iv. Blood samples were collected for estimating the creatine kinase-myocardial band (CK-MB) value. Cardiac muscle sections from all groups were examined by fluorescence microscope. All sections were processed for histological study using Hx&E and Masson's trichrome stains in addition to immunohistochemical staining for Cx43 and CD44.Morphometric and statistical studies were done. Results: Group II revealed fragmented muscle fibers and cytoplasmic vacuolation in addition to loss of transverse striation. These changes were confirmed by significant increase in the mean value of CK-MB and the mean area % of collagen fibers when compared to all other groups. In group III, regression of the previous changes was noticed and there was a significant decrease in the mean area % of collagen fibers when compared to group II. Group IV cardiomyocytes appeared healthy with normal arrangement and non-significant difference in mean area % of collagen fibers versus the control. Studying all groups immunohistochemically, revealed increase in positive reactions in LOS and SC groups when compared to DOX group with more increase in SC group than LOS group. Conclusion: Losartan improves cardiac injury with little effect on cardiac regeneration. MSCs have promising potential in cardiac regeneration.