Time filter

Source Type

Elliott M.J.,University College London | Speggiorin S.,University College London | Butler C.R.,Hospital for Children | Samuel E.,University College London | And 15 more authors.
The Lancet | Year: 2012

Background Stem-cell-based, tissue engineered transplants might off er new therapeutic options for patients, including children, with failing organs. The reported replacement of an adult airway using stem cells on a biological scaff old with good results at 6 months supports this view. We describe the case of a child who received a stem-cell-based tracheal replacement and report fi ndings after 2 years of follow-up. Methods A 12-year-old boy was born with long-segment congenital tracheal stenosis and pulmonary sling. His airway had been maintained by metal stents, but, after failure, a cadaveric donor tracheal scaff old was decellularised. After a short course of granulocyte colony stimulating factor, bone marrow mesenchymal stem cells were retrieved preoperatively and seeded onto the scaff old, with patches of autologous epithelium. Topical human recombinant erythropoietin was applied to encourage angiogenesis, and transforming growth factor β to support chondrogenesis. Intravenous human recombinant erythropoietin was continued postoperatively. Outcomes were survival, morbidity, endoscopic appearance, cytology and proteomics of brushings, and peripheral blood counts. Findings The graft revascularised within 1 week after surgery. A strong neutrophil response was noted locally for the fi rst 8 weeks after surgery, which generated luminal DNA neutrophil extracellular traps. Cytological evidence of restoration of the epithelium was not evident until 1 year. The graft did not have biomechanical strength focally until 18 months, but the patient has not needed any medical intervention since then. 18 months after surgery, he had a normal chest CT scan and ventilation-perfusion scan and had grown 11 cm in height since the operation. At 2 years follow-up, he had a functional airway and had returned to school. Interpretation Follow-up of the fi rst paediatric, stem-cell-based, tissue-engineered transplant shows potential for this technology but also highlights the need for further research. Funding Great Ormond Street Hospital NHS Trust, The Royal Free Hampstead NHS Trust, University College Hospital NHS Foundation Trust, and Region of Tuscany.

Kme C.,Center for Molecular Cell Biology | Minogue S.,Center for Molecular Cell Biology | Hsuan J.J.,Center for Molecular Cell Biology | Waugh M.G.,Center for Molecular Cell Biology
Cell Death and Disease | Year: 2010

In this study, we investigated the role of PI4P synthesis by the phosphatidylinositol 4-kinases, PI4KIIα and PI4KIIIβ, in epidermal growth factor (EGF)-stimulated phosphoinositide signaling and cell survival. In COS-7 cells, knockdown of either isozyme by RNA interference reduced basal levels of PI4P and PI(4,5)P 2, without affecting receptor activation. Only knockdown of PI4KIIa inhibited EGF-stimulated Akt phosphorylation, indicating that decreased PI(4,5)P 2 synthesis observed by loss of either isoform could not account for this PI4KIIa-specific effect. Phospholipase Cc activation was also differentially affected by knockdown of either PI4K isozyme. Overexpression of kinase-inactive PI4KIIα, which induces defective endosomal trafficking without reducing PI(4,5)P 2 levels, also reduced Akt activation. Furthermore, PI4KIIα knockdown profoundly inhibited cell proliferation and induced apoptosis as evidenced by the cleavage of caspase-3 and its substrate poly(ADP-ribose) polymerase. However, in MDA-MB-231 breast cancer cells, apoptosis was observed subsequent to knockdown of either PI4KIIα or PI4KIIIβ and this correlated with enhanced proapoptotic Akt phosphorylation. The differential effects of phosphatidylinositol 4-kinase knockdown in the two cell lines lead to the conclusion that phosphoinositide turnover is inhibited through PI4P substrate depletion, whereas impaired antiapoptotic Akt signaling is an indirect consequence of dysfunctional endosomal trafficking. © 2010 Macmillan Publishers Limited All rights reserved.

Loading Center for Molecular Cell Biology collaborators
Loading Center for Molecular Cell Biology collaborators