Cultured human epithelium: Human umbilical cord blood stem cells differentiate into keratinocytes under in vitro conditions
Introduction
Stem cells have the unique capacity to either self-renew or to give rise to a specialized cell type [1]. Bone marrow (BM) contains stem cells (haematopoietic stem cells, HSC), which differentiate into all mature blood cells and marrow stromal cells. They have the capacity to differentiate into mature cells in multiple mesenchymal tissues, including fat, bone, and cartilage [2], [3], [4]. Recent studies indicate that HSC also differentiate into cells of ectodermal, mesodermal and endodermal tissues. Human umbilical cord blood (HUCB) has been explored as an alternative source of stem cells to repopulate the BM in the treatment of diseases in children and adults [5], [6], [7]. Moreover, in contrast to BM aspiration, HUCB is obtained by a simple, safe and painless procedure. Thus, HUCB has become an indispensable source to treat hematological disorders [8], [9]. However, its potential to differentiate into cells of other tissues like skin is still under discussion.
Cultured epidermis has been used as grafting material in different clinical situations such as treatment of burn wounds [10], chronic skin ulcers [11], and oral mucous defects [12]. This method has gained attention in the treatment of seriously burned patients, since it allows grafting of an epithelial surface, large enough to cover the needs of a patient [13]. Rapid and effective burn wound closure is one of the most important aspects in the treatment of burn patients, because the patient is in a sub-septic condition, until all skin defects are closed. Unfortunately, in larger burns there is a lack of donor sites for grafting procedures.
Bearing in mind the possible use of cultured skin substitutes for the treatment of seriously burned patients, we evaluated if HUCB stem cells were capable to differentiate into epithelial cells which in turn could be transplanted onto skin defects. One major aspect was to evaluate, if they differentiated into Keratinocytes isolated under in vitro conditions. We conducted our in vitro study with female keratinocytes and male HUCB stem cells to study the possible contribution of HUCB stem cells to the regeneration of skin tissue.
Section snippets
Primary keratinocyte culture
Normal human keratinocytes derived from adult female skin donors, were isolated as previously described [14]. Briefly, a skin section was incubated in trypsin-EDTA for 18 h at 4 °C in order to obtain individual cells. Keratinocytes were then cultured on fibrin glue/fibroblasts gels as a control group. Where indicated, male umbilical cord blood cells were added at an 1:10 ratio to the keratinocytes and co-cultured on the fibrin glue/fibroblasts gel as the treatment-umbilical cord blood cell group.
Morphological and differentiation features of keratinocytes
At day 15, a regular epithelial sheet consisting of three to four layers of cells was formed. A limiting membrane demarcating the keratinocytes from the fibrin matrix was discernible. Squamous differentiation with flattening out of cells similar to Strata reticulare and corneum found in vivo were observed. Nuclei of basal cells were regularly spaced from each other and the chromatin was of homogeneous appearance without prominent nucleoli. Mitoses were rare. Between both groups no
Discussion
At the moment, several technologies are under active development to aid cutaneous wound repair [14]. However, many of them deal with a single aspect of the healing process that does not necessarily serve as a primary source of new tissue. Nowadays there has been a great deal of interest in using stem cells in tissue regeneration [16]. Stem cells are defined as cells capable to perform self-renewal and multi-lineage differentiation [17]. Embryonic stem cells are totipotent, have the potential to
References (19)
- et al.
Multicentre experience in the treatmment of burns with autologus and allogenic cultured epithelim, fresh or preserved in a frozen state
Burns
(1989) - et al.
The Viennese culture method: cultured human epithelium obtained on a dermal matrix based on fibroblast containing fibrin glue gels
Burns
(2005) - et al.
Sex determination by polymerase chain reaction on mummies discovered at Taklamakan desert in 1912
Forensic Sci Int
(1995) - et al.
Absence of donor-derived kratinocyte stem cells in skin tissues cultured from patients after mobilized peripheral blood hematopoietic stem cell transplantation
Exp Hematol
(2002) - et al.
Stem cell plasticity in the hematopoietic system
Int J Hematol
(2004) - et al.
Multilineag potential of adult human msenchymal stem cells
Science
(1999) - et al.
Use of mesenchymal stem cells in a collagen matrix for Achilles tendon repair
J Orthop Res
(1998) - et al.
Differentiation potential of conditionally immortalized mesenchymal progenitor cells from adult marrow of a H-2Kb-tsA58 transgenic mouse
J Cell Physiol
(1996) - et al.
Transplants of umbilical-cord blood or bone marrow from unrelated donors in adults with acute leukemia
N Engl J Med
(2004)