Therapeutic Potential of Bone Marrow-Derived Mesenchymal Stem Cells on Experimental Liver Injury Induced by Schistosoma mansoni: A Histological Study

BACKGROUND AND OBJECTIVES: Bone marrow derived mesenchymal stem cells (BM-MSCs) have been proposed as effective treatment of many diseases owing to their unique ability to differentiate into other cell types in vivo. Schistosoma mansoni (S. mansoni) infection is characterized by hepatic granuloma formation around schistosome eggs at acute stage of infection, followed by hepatic fibrosis at chronic and advanced stages. Whether BM-MSCs have an ameliorative effect on hepatic tissue injury caused by S. mansoni infection or not, was inspected in the current study. MATERIALS AND RESULTS: Female Swiss Albino mice were divided into a control group and an experimental group. Half of control animals served as donors for bone marrow stem cells, and the other half was used to collect liver samples. Experimental group was injected with circariae of S. mansoni, and then subdivided into three subgroups; Subgroup B1, sacrificed after eight weeks of infection without treatment, subgroup B2, received BM-MSCs at the eighth week and sacrificed four weeks later, and subgroup B3, was untreated till the twelfth week of infection. Histological examination of liver samples showed the formation of granulomas and liver fibrosis which were extensive in subgroup B3. However, treated subgroup illustrated improvement of liver histology, signs of hepatocytes regeneration, and possible contribution of oval cell in the process of hepatic and biliary regeneration. CONCLUSION: BM-MSCs decreased liver fibrosis and contributed to an increase in oval cells, generation of new hepatocytes and/or to the improvement of resident hepatocytes in S. mansoni infected mice.

Preparation of an acellular dermal matrix using the freeze-thawing technique with and without gamma irradiation

An acellular dermal matrix [ADM] is a dermal substitute in which the skin is treated to remove epithelial and dermal cellular components. To compare the histological and immunohistochemical structures of ADMs prepared using the freeze-thawing technique with or without gamma irradiation. Twenty-one human skin specimens were used and divided into three equal groups: group I [control group], group II, in which skin specimens were subjected to three repeated freeze-thawing cycles, and group III, in which skin specimens were subjected to three repeated freeze-thawing cycles and subsequent exposure to 5000 rad gamma irradiation. Skin specimens from the previous groups were examined histologically and immunohistochemically for laminin. A morphometric study was carried out for the determination of the number of cells per high-power field [hpf] in both the papillary and the reticular dermis. Both methods of ADM preparation resulted in extensive extraction of cellular components with preservation of the basic dermal architecture as there was a highly significant decrease in the number of cells/hpf in both layers of the dermis in groups II and III as compared with the control group [P<0.001]. However, there was further decellularization in group III as there was a highly significant decrease in the number of cells/ hpf in both the papillary and the reticular dermis in group III as compared with group II [P<0.001]. Immunohistochemical stain of laminin revealed preservation of the epidermal basement membrane in groups II and III. A combination of irradiation and a freeze-thawing technique is recommended in the preparation of ADM for efficient decellularization