Cord blood (CB) is a rich source of hematopoietic stem cells (HSCs) and for this reason CB transplantation has been used successfully for the treatment of some malignant and nonmalignant diseases. However, this technique is limited by the relatively low number of HSCs present in each CB unit and by the delayed engraftment of platelets and neutrophils. To bypass these obstacles efforts have been made to develop strategies to expand CB HSCs in vitro for transplantation. CB is also an important source of other stem cells, including endothelial progenitors, mesenchymal stem cells (MSCs), very small embryonic/epiblast-like (VSEL) stem cells, and unrestricted somatic stem cells (USSC), potentially suitable for use in regenerative medicine. For some of these stem cell populations, such as MSCs, clinical studies have been started and for other stem cell populations potential clinical applications have been identified and clinical studies will follow. In addition to CB, other parts of umbilical cord, such as the Wharton's jelly, or tissues strictly linked such as the placenta are also rich sources of stem cells.

Human bone marrow mesenchymal stem cells (hBMMSCs) were shown to transform into tumor-associated fibroblasts (TAFs) when in the vicinity of breast cancer tumors and played an important role in tumor enhancement and metastasis. In early human development MSCs migrating from the yolk sac and aorta-gonad-mesonephros (AGM) via the umbilical cord to the placenta and back to the fetal bone marrow were shown to get trapped in the gelatinous Wharton's jelly of the umbilical cord. The common origin of the Wharton's jelly MSCs and the finally homed hBMMSCs prompted us to evaluate whether hWJSCs are also involved in TAF transformation. hWJSCs and hBMMSCs were grown in the presence of breast and ovarian cancer cell conditioned medium (MDA-TCM, TOV-TCM) for 30 days. No changes were observed in the hWJSCs but the hBMMSCs transformed from short to thin long fibroblasts, their proliferation rates increased and CD marker expression decreased. The transformed hBMMSCs showed positive staining for the tumor-associated markers FSP, VEGF, EGF and Tn-C. Real-time PCR and multiplex luminex bead analysis showed upregulation of TAF-related genes (FSP, FAP, Tn-C, Tsp-1, EGF, bFGF, IL-6, a-SMA, VEGF and TGF-β) for hBMMSCs with low expression for hWJSCs. The luciferase assay showed that hWJSCs previously exposed to MDA-TCM or TOV-TCM had no stimulatory growth effect on luciferase-tagged MDA or TOV cells unlike hBMMSCs. The results confirmed that hWJSCs do not transform to the TAF phenotype and may therefore not be associated with enhanced growth of solid tumors making them a safe MSC for cell based therapies. J. Cell. Biochem. © 2012 Wiley Periodicals, Inc.

INTRODUCTION:Afterbirth tissues, which include the umbilical cord, placenta, amnion, and cord blood, are usually discarded. Recent progress in regenerative medicine suggests that we re-evaluate these tissues and assess their therapeutic potential.

METHODS:Firstly the unique properties of afterbirth tissues and their current use in regenerative medicine are summarised. Then we introduce the cooperation of our institutions and our experiences regarding the collection and utilisation of afterbirth tissues.

RESULTS:A literature survey suggests that besides the well-known transplantation of hematopoietic stem cells from cord blood, afterbirth tissues were also used as a source of stem cells, progenitor cells, differentiated cells, and blood vessels for tissue engineering purposes. According to our own experience, the two participating OB/GYN departments and the blood donation service were able to organise a sufficient supply of umbilical cords for research purposes. The yield correlated with incentives for the midwives. A total of more than 4,300 cords was collected for experiments designed to create small caliber vessel grafts. The contamination rate was low. Birth mode significantly affected umbilical vein function, whereas ischaemia for up to 40 h did not have any deleterious effects. Umbilical veins were cryopreserved with a moderate loss of function. Fresh umbilical veins were endothelium-denuded and reseeded with endothelial cells harvested from coronary artery disease patients to generate an autologous surface.

CONCLUSIONS:Afterbirth tissues have unique properties which make them ideally suited for regenerative medicine. These tissues can be procured and utilised in research facilities even in the absence of an in-house birthing centre.