In our opinion scaffold preseeding only with urothelial cells is not necessary, especially for small scaffold such as used for urinary conduit creation because urothelium can easy selfregenerate from surrounding tissue. We think, that the LDK378 dihydrochloride important fact is provide scaffold protection from urine leakage. The liver possesses great regenerative capacity in response to injury. However, chronic injuries caused by autoimmune hepatitis, alcohol abuse, metabolic disorders, or viral hepatitis, could disturb the regenerative process, leading to development of a common pathology known as liver fibrosis. In some cases, persistent injuries progress the fibrosis and eventually lead to liver cirrhosis. At this stage, the only therapeutic option is organ transplantation. Liver transplants are not widely performed because of problems such as donor shortage, surgical invasiveness, risk of immunological rejection, and medical costs. Therefore, it is essential that therapeutic alternatives to liver transplantation are developed. Recently, the emergence of stem cell research has opened new possibilities for the treatment of chronic liver diseases. Various cell populations from the bone marrow, including hematopoietic stem cells, mesenchymal stem cells, endothelial progenitor cells, and bone marrow mononuclear cells, have been transplanted and have proved to be functional for the prevention of liver fibrosis in animal models, as well as in patients. The transplanted cells likely play multiple roles in the repair process. They may differentiate directly into hepatocytes, or release growth factors to protect intrinsic hepatocytes, stimulate regeneration, regulate inflammatory response, and/or decompose the Tipiracil hydrochloride extracellular matrix. Although non-cultured autologous bone marrowderived cells have been successfully applied in patients, the use of in vitro culture-expanded cells for treatment could reduce the initial amount of bone marrow needed. Expansion of stem cells in culture is still a big challenge in the field. For example, it is difficult and expensive to expand EPCs without losing their stemness and function.