Читать книгу Genetic Disorders and the Fetus - Группа авторов - Страница 138

Multipotent mesenchymal stem cells (MSCs) can be obtained from several tissue sources and are of great interest for their potential uses in gene therapy and tissue repair. Those derived from adult bone marrow or other sources apart from AFCs have some drawbacks including their relative rarity and slow rate of proliferation in vitro. In contrast, MSCs derived from AFCs have distinct advantages.^675–679 MSCs comprise about 1 percent of the cells in midtrimester AF and likely derive from fibroblastic F‐type cells.⁶⁷⁵ Recent advances in the isolation and culture of MSCs from AF are welcomed because these cells apparently do not form teratomas and are not tumorigenic even after many passages. Amniotic MSCs proliferate well and have stable normal telomeres, cytogenetics, and cell surface markers of pleuripotency, similar to embryonic stem cells. Amniotic MSCs also circumvent ethical objections associated with the use of embryonic stem cells.

Although more research is needed, amniotic MSCs appear to have immunogenic characteristics that are favorable for allogenic transplantation.⁶⁸⁰ They can be coaxed into differentiation along many lineages such as adipogenic, osteogenic, myogenic, endothelial, neurogenic, pancreatic, and hepatic, and including mesodermal, ectodermal, and endodermal lineages.^{480, 676, 678, 681–683} These cells are likely to find utility in a wide variety of cellular therapies,^{481, 675} including anticancer combination therapy.⁶⁸⁴ In a demonstration of whole‐tissue engineering for early repair of congenital malformations, heart valves have been fabricated using amniotic MSCs. The engineered heart valves exhibited normal endothelial surfaces and adequate opening and closing behavior.⁴⁷⁹ Under appropriate conditions, amniotic MSCs can form bone.⁶⁷⁶ The potential exists for amniotic MSCs to be employed for engineering tissues in time to be implanted shortly after birth to repair malformations of the heart, skin, bladder, or diaphragm.^{479, 685–687} This approach is unlikely, at least in the short term, to be helpful in the fetal therapy of spina bifida (see Chapters 29 and 30).