Neuronal hypoxia in vitro: Investigation of therapeutic principles of HUCB-MNC and CD133+ stem cells

A human in vitro model of neuronal hypoxia was used to address the impact of total HUCB-MNC (tMNC), a stem cell enriched fraction (CD133+, 97.38% CD133-positive cells) and a stem cell depleted fraction (CD133-, 0.06% CD133-positive cells) of HUCB-MNC by either direct or indirect co-cultivation with post-hypoxic neuronal cells (differentiated SH-SY5Y). Over three days, development of apoptosis and necrosis of neuronal cells, chemotaxis of MNC and production of chemokines (CCL2, CCL3, CCL5, CXCL8, CXCL9) and growth factors (G-CSF, GM-CSF, VEGF, bFGF) were analyzed using fluorescence microscopy, FACS and cytometric bead array.tMNC, CD133+ and surprisingly CD133- reduced neuronal apoptosis in direct co-cultivations significantly to levels in the range of normoxic controls (7% ± 3%). Untreated post-hypoxic control cultures showed apoptosis rates of 85% ± 11%. tMNC actively migrated towards injured neuronal cells. Both co-cultivation types using tMNC or CD133- reduced apoptosis comparably. CD133- produced high concentrations of CCL3 and neuroprotective G-CSF within indirect co-cultures. Soluble factors produced by CD133+ cells were not detectable in direct co-cultures.Our data show that heterogeneous tMNC and even CD133-depleted fractions have the capability not only to reduce apoptosis in neuronal cells but also to trigger the retaining of neuronal phenotypes.Transplantation of adult stem cells has been shown to be an auspicious and effective treatment for degenerative and traumatic neurological diseases [1]. Among degenerative neurological disorders acute ischemic stroke is the leading cause of disability and death in industrial nations [2-4].Acute stroke leads to an increased release of hematopoietic stem and progenitor cells from bone marrow into peripheral blood [5]. It is assumed that these cells take part in self-healing processes occurring after neuronal injury. They are supposed to promote the survival of the injured brain tissue by producing neurotrophic factors