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

Background The therapeutic capacity of human umbilical cord blood mononuclear cells (HUCB-MNC) and stem cells derived thereof is documented in animal models of focal cerebral ischemia, while mechanisms behind the reduction of lesion size and the observed improvement of behavioral skills still remain poorly understood. Methods 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. Results 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. Conclusion 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

Electrospun Polyurethane Fibers for Absorption of Volatile Organic Compounds from Air

Electrospun polyurethane fibers for removal of volatile organic compounds (VOC) from air with rapid VOC absorption and desorption have been developed. Polyurethanes based on 4,4-methylenebis(phenylisocyanate) (MDI) and aliphatic isophorone diisocyanate as the hard segments and butanediol and tetramethylene glycol as the soft segments were electrospun from their solutions in N,N-dimethylformamide to form micrometer-sized fibers. Although activated carbon possessed a many-fold higher surface area than the polyurethane fiber meshes, the sorption capacity of the polyurethane fibers was found to be similar to that of activated carbon specifically designed for vapor adsorption. Furthermore, in contrast to VOC sorption on activated carbon, where complete regeneration of the adsorbent was not possible, the polyurethane fibers demonstrated a completely reversible absorption and desorption, with desorption obtained by a simple purging with nitrogen at room temperature. The fibers possessed a high affinity toward toluene and chloroform, but aliphatic hexane lacked the necessary strong attractive interactions with the polyurethane chains and therefore was less strongly absorbed. The selectivity of the polyurethane fibers toward different vapors, along with the ease of regeneration, makes them attractive materials for VOC filtration.Boeing CompanyNetherlands Organisation for Scientific Research (NWO) (Talent Scholarship

Experimentelle Schlaganfallbehandlung mittels CD34+- und CD34--Nabelschnurblutzellen in spontan hypertensiven Ratten

Human umbilical cord blood as a source of stem cells has recently been reported in experimental treatment of cerebral disorders. However, little is known about the nature of cells and cellular mechanisms leading to neurofunctional improvement. Here we investigated the potential of separated CD34+ versus CD34- human umbilical cord blood cells (HUCBC) to promote functional recovery following stroke. The experiments were performed in spontaneously hypertensive (SH) rats, known for a risk profile comparable to stroke patients.After three weeks of behavioral training in the RotaRod and Beamwalk test arrays, stroke was induced by permanent middle cerebral artery occlusion (MCAO). For cell therapy, 1x106 cryopreserved cells were administered systemically between 8 and 10 hours after MCAO. The behavioral tests were performed together with a neurological severity score (mNSS) until day 29 to assess neurofunctional disabilities. Nearly complete functional remission was observed with both subpopulations CD34+ as well as CD34- cells. To localize cells histologically, they were labeled with a fluorescence dye (CFSE) before injection. Again, after administration of CD34+ as well as CD34- cells, CFSE labelled cells were found that accumulated in the border zone between the central necrosis of the ischemic lesion and functional brain tissue, thus indicating active attraction towards the lesion for both cell populations. Immunohistology with anti-CD68 and antibodies to human neuronal markers (NF-L, chromogranin) indicated an accumulation of human and rat monocytes in the border zone of the lesion while neuronal cells of human origin could not be detected in host brains.Obwohl humanes Nabelschnurblut als Quelle von Stammzellen für experimentelle Therapien von Erkrankungen des Zentralnervensystems derzeit intensiv untersucht wird, ist noch wenig über die zellulären Prozesse bekannt, die der funktionellen Verbesserung von Ausfallerscheinungen zugrunde liegen. In der vorliegenden Studie untersuchten wir das Potenzial humaner Nabelschnurblutzellen, funktionelle Verbesserungen nach einem experimentellen Schlaganfall zu unterstützen. Die Experimente wurden mit spontan hypertensiven (SH) Ratten durchgeführt, deren metabolische Grunderkrankungen dem Risikoprofil menschlicher Schlaganfallpatienten entsprechen.Nach drei Wochen der Konditionierung für die Verhaltenstests RotaRod und Beamwalk wurde ein experimenteller Schlaganfall durch permanente Okklusion der mittleren Hirnarterie (middle cerebral artery occlusion, MCAO) ausgelöst. Im Zuge der Zelltherapie wurden 1x106 kryokonservierte CD34+- oder CD34--Zellen 8 bis 10 Stunden nach Verschluss der rechten mittleren Hirnarterie intravenös appliziert. Die Verhaltenstests wurden zusammen mit der Erhebung des modified neurological severity score (mNSS) bis 29 Tage nach Eintritt des experimentellen Schlaganfalls durchgeführt, um die Entwicklung neurofunktionaler Defizite im Verlauf beurteilen und quantifizieren zu können. Dabei wurde eine annähernd komplette Rückbildung von Ausfallerscheinungen bei Gabe beider Zellpopulationen beobachtet. Um transplantierte Zellen lokalisieren zu können, wurden diese mit dem Fluoreszenzfarbstoff CFSE unmittelbar vor der systemischen Zellgabe markiert. Sowohl nach der Gabe von CD34+- als auch CD34--Zellen konnten CFSE-markierte Zellen in der Grenzzone zwischen zentraler Kolliquationsnekrose und funktionellem Hirngewebe detektiert werden. Immunhistologische Untersuchungen mit anti-CD68 Antikörpern gegen neuronale Marker (NF-L, Chromogranin) zeigten eine verstärkte Ansammlung von Zellen monozytärer Natur, während neuronale Zellen humanen Ursprungs nicht identifiziert werden konnten