Efficiency of non-viral gene delivery systems to rat lungs

Objective: Transient expression of therapeutic genes within lung allografts may modulate the pathological processes following allotransplantation. Whilst efficient gene transfer to lungs has been reported with viral vectors, their usefulness is limited on the grounds of safety. Since non-viral systems overcome many of these safety issues, our studies were designed to evaluate the efficiency of several non-viral gene delivery vectors for in vivo transfer of plasmid DNA to rat lungs via the airways. Methods: Fischer rats (230-260 g) underwent a thoracotomy, right main bronchus occlusion and instillation of 300 µg naked or complexed DNA (pCIluci, luciferase gene/CMV promoter) to the left lung followed by ventilation for 10 min. Rats were divided into five treatment groups (n=5): (1) Glucose, (2) Naked DNA, (3) Linear polyethylenimine (PEI), (4) Branched PEI, (5) Lipid GL-67/DOPE and (6) DOTAP/cholesterol. Animals were sacrificed 24 h after gene delivery for measurement of reporter gene activity and gas exchange of the left lung. Results: Linear PEI was the most efficient gene delivery vector and was significantly better than DOTAP/cholesterol (P=0.00002) and naked DNA (P=0.004). All gene delivery vectors impaired function of the transfected left lung compared with DNA alone. Of all the gene delivery vectors tested, lipid GL-67/DOPE exerted the least effect on lung function whilst DOTAP/cholesterol mediated the most adverse effect. Conclusion: Linear PEI was the most efficient vector for gene delivery to rat lungs in our experimental setting although it mediated a moderate impairment in lung function. Further studies are needed to evaluate whether this effect is transien

Buttressing staples with cholecyst-derived extracellular matrix (CEM) reinforces staple lines in an ex vivo peristaltic inflation model

This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ Springer Science + Business Media, LLC 2008Background - Staple line leakage and bleeding are the most common problems associated with the use of surgical staplers for gastrointestinal resection and anastomotic procedures. These complications can be reduced by reinforcing the staple lines with buttressing materials. The current study reports the potential use of cholecyst-derived extracellular matrix (CEM) in non-crosslinked (NCEM) and crosslinked (XCEM) forms, and compares their mechanical performance with clinically available buttress materials [small intestinal submucosa (SIS) and bovine pericardium (BP)] in an ex vivo small intestine model. Methods - Three crosslinked CEM variants (XCEM0005, XCEM001, and XCEM0033) with different degree of crosslinking were produced. An ex vivo peristaltic inflation model was established. Porcine small intestine segments were stapled on one end, using buttressed or non-buttressed surgical staplers. The opened, non-stapled ends were connected to a peristaltic pump and pressure transducer and sealed. The staple lines were then exposed to increased intraluminal pressure in a peristaltic manner. Both the leak and burst pressures of the test specimens were recorded. Results - The leak pressures observed for non-crosslinked NCEM (137.8 ± 22.3 mmHg), crosslinked XCEM0005 (109.1 ± 14.1 mmHg), XCEM001 (150.1 ± 16.0 mmHg), XCEM0033 (98.8 ± 10.5 mmHg) reinforced staple lines were significantly higher when compared to non-buttressed control (28.3 ± 10.8 mmHg) and SIS (one and four layers) (62.6 ± 11.8 and 57.6 ± 12.3 mmHg, respectively) buttressed staple lines. NCEM and XCEM were comparable to that observed for BP buttressed staple lines (138.8 ± 3.6 mmHg). Only specimens with reinforced staple lines were able to achieve high intraluminal pressures (ruptured at the intestinal mesentery), indicating that buttress reinforcements were able to withstand pressure higher than that of natural tissue (physiological failure). Conclusions - These findings suggest that the use of CEM and XCEM as buttressing materials is associated with reinforced staple lines and increased leak pressures when compared to non-buttressed staple lines. CEM and XCEM were found to perform comparably with clinically available buttress materials in this ex vivo model.Enterprise Irelan

Several clinical interests regarding lung volume reduction surgery for severe emphysema: meta-analysis and systematic review of randomized controlled trials

<p>Abstract</p> <p>Objectives</p> <p>We aim to address several clinical interests regarding lung volume reduction surgery (LVRS) for severe emphysema using meta-analysis and systematic review of randomized controlled trials (RCTs).</p> <p>Methods</p> <p>Eight RCTs published from 1999 to 2010 were identified and synthesized to compare the efficacy and safety of LVRS vs conservative medical therapy. One RCT was obtained regarding comparison of median sternotomy (MS) and video-assisted thoracoscopic surgery (VATS). And three RCTs were available evaluating clinical efficacy of using bovine pericardium for buttressing, autologous fibrin sealant and BioGlue, respectively.</p> <p>Results</p> <p>Odds ratio (95%CI), expressed as the mortality of group A (the group underwent LVRS) versus group B (conservative medical therapies), was 5.16(2.84, 9.35) in 3 months, 3(0.94, 9.57) in 6 months, 1.05(0.82, 1.33) in 12 months, respectively. On the 3^rd, 6^thand 12^thmonth, all lung function indices of group A were improved more significantly as compared with group B. PaO2 and PaCO2 on the 6^thand 12^thmonth showed the same trend. 6MWD of group A on the 6^thmonth and 12^thmonth were improved significantly than of group B, despite no difference on the 3^rdmonth. Quality of life (QOL) of group A was better than of group B in 6 and 12 months. VATS is preferred to MS, due to the earlier recovery and lower cost. And autologous fibrin sealant and BioGlue seems to be the efficacious methods to reduce air leak following LVRS.</p> <p>Conclusions</p> <p>LVRS offers the more benefits regarding survival, lung function, gas exchange, exercise capacity and QOL, despite the higher mortality in initial three postoperative months. LVRS, with the optimization of surgical approach and material for reinforcement of the staple lines, should be recommended to patients suffering from severe heterogeneous emphysema.</p

Cell Membrane Modification for Rapid Display of Bi-Functional Peptides: A Novel Approach to Reduce Complement Activation

Ischemia and reperfusion of organs is an unavoidable consequence of transplantation. Inflammatory events associated with reperfusion injury are in part attributed to excessive complement activation. Systemic administration of complement inhibitors reduces reperfusion injury but leaves patients vulnerable to infection. Here, we report a novel therapeutic strategy that decorates cells with an anti-complement peptide. An analog of the C3 convertase inhibitor Compstatin (C) was synthesized with a hexahistidine (His6) tag to create C-His6. To decorate cell membranes with C-His6, fusogenic lipid vesicles (FLVs) were used to incorporate lipids with nickel (Ni2+) tethers into cell membranes, and these could then couple with C-His6. Ni2+ tether levels to display C-His6 were modulated by changing FLV formulation, FLV incubation time and FLV levels. SKOV-3 cells decorated with C-His6 effectively reduced complement deposition in a classical complement activation assay. We conclude that our therapeutic approach appears promising for local ex vivo treatment of transplanted organs to reduce complement-mediated reperfusion injury