The effects of PPAR? agonist rosiglitazone on neointimal hyperplasia in rabbit carotid anastomosis model

PubMed ID: 22716287Background: Neointimal hyperplasia involving smooth muscle cell (SMC) proliferation, migration and extracellular matrix (ECM) degradation is an important component of atherosclerosis. It develops as a response to vascular injury after balloon angioplasty and vascular graft placement. Matrix metalloproteinases (MMPs) induce SMC proliferation, migration and contribute to intimal hyperplasia by degrading ECM. PPAR? agonists inhibit SMC proliferation, migration and lesion formation. In this study, we aimed to investigate the effects of PPAR? agonist rosiglitazone on neointimal hyperplasia and gelatinase (MMP-2 and MMP-9) expressions in rabbit carotid anastomosis model.Methods: New Zealand white rabbits (n = 13, 2.7-3.2 kg) were divided into placebo and treatment groups. Right carotid artery (CA) was transected and both ends were anastomosed. Treatment group (n = 6) received rosiglitazone (3 mg/kg/day/p.o.) and placebo group (n = 7) received PBS (phosphate buffered saline, 2.5 ml/kg/day/p.o.) for 4 weeks postoperatively. After the sacrification, right and left CAs were isolated. Morphometric analyses and immunohistochemical examinations for gelatinases were performed.Results: Intimal area (0.055 ± 0.005 control vs 0.291 ± 0.020 µm 2 anastomosed, p < 0,05) and index (0.117 ± 0.002 control vs 0.574 ± 0.013 anastomosed, p < 0,01) significantly increased in anastomosed arteries compared to control arteries from placebo group. However, in rosiglitazone-treated group, intimal area (0.291 ± 0.020 PBS vs 0.143 ± 0.027 rosiglitazone, p < 0,05) and index (0.574 ± 0.013 PBS vs 0.263 ± 0.0078 rosiglitazone, p < 0,01) significantly decreased. Furthermore, gelatinase immunopositivity was found to have significantly increased in anastomosed arteries from placebo group and decreased with rosiglitazone treatment.Conclusions: These results suggest that rosiglitazone may prevent neointimal hyperplasia, which is the most important factor involved in late graft failure, by inhibiting gelatinase enzyme expression. © 2012 Guzeloglu et al.; licensee BioMed Central Ltd

A novel incentive-based retail demand response program for collaborative participation of small customers

Integration of aggregated demand response into the wholesale electricity market is an emerging field of research. Contrary to conventional service providers, most of the demand side participants act voluntarily. However, due to wholesale market regulations, reliable and effective participation of huge numbers of customers is a vital task for aggregators. The existing retail programs aim to motivate customers to take part in events in return for static or individual performance-based incentives. These programs do not focus on engaging customers to act in a collaborative way and therefore have limited effectiveness. This study proposes a novel retail demand response program in which the incentives are dependent on the aggregated performance of participants. Considering the existing wholesale and retail market structures together with demand response aggregator responsibilities, an adaptable program is developed for more effective performance and indirect collaboration of customers. The contribution of the program is compared with a number of different DR programs adopting concepts from game theory