BackgroundInhibition of mechanistic target of rapamycin (mTOR) has emerged as a viable means to lengthen lifespan and healthspan in mice, although it is still unclear whether these benefits will extend to other mammalian species. We previously reported results from a pilot experiment wherein common marmosets (Callithrix jacchus) were treated orally with rapamycin to reduce mTOR signaling in vivo in line with previous reports in mice and humans. Further, long-term treatment did not significantly alter body weight, daily activity, blood lipid concentrations, or glucose metabolism in this cohort.MethodsIn this study, we report on the molecular consequences of rapamycin treatment in marmosets on mechanisms that regulate protein homeostasis (proteostasis) in vivo. There is growing appreciation for the role of proteostasis in longevity and for the role that mTOR plays in regulating this process. Tissue samples of liver and skeletal muscle from marmosets in our pilot cohort were assessed for expression and activity of components of the ubiquitin-proteasome system, macroautophagy, and protein chaperones.ResultsRapamycin treatment was associated with increased expression of PSMB5, a core subunit of the 20S proteasome, but not PSMB8 which is involved in the formation of the immunoproteasome, in the skeletal muscle and liver. Surprisingly, proteasome activity measured in these tissues was not affected by rapamycin. Rapamycin treatment was associated with an increased expression of mitochondria-targeted protein chaperones in skeletal muscle, but not liver. Finally, autophagy was increased in skeletal muscle and adipose, but not liver, from rapamycin-treated marmosets.ConclusionsOverall, these data show tissue-specific upregulation of some, but not all, components of the proteostasis network in common marmosets treated with a pharmaceutical inhibitor of mTOR.
Objectives: To provide an overview of recent techniques and technologies for the application of topical corticosteroid therapy immediately following endoscopic sinus surgery (ESS) for chronic rhinosinusitis (CRS). Methods: A comprehensive search in the PubMed and Google Scholar databases was conducted to identify publications between January 2000 and December 2019 detailing clinical trials that have evaluated the efficacy and safety of intraoperative applications of topical corticosteroids for CRS. Results: A total of 21 articles, all of which highlight a variety of corticosteroid-infused products, including Propel corticosteroid-eluting stents, NasoPore, Merocel, SinuBand, calcium alginate, and bioresorbable gel-type products, are included for review. Propel stents are the only devices that have achieved level 1A evidence in terms of efficacy and have data to support their safety. The remaining products have shown mixed results in terms of efficacy and safety. Conclusion: A wide range of techniques and technologies have been introduced to enhance the topical delivery of corticosteroids into the neosinuses after ESS for CRS. Regarding efficacy, there is level 1A evidence to support the use of Propel stents. Most of the remaining strategies show some degree of efficacy. Direct comparisons across the different strategies are limited owing to the varied uses of delivery vectors, corticosteroid choices, and doses of corticosteroids. Propel stents and SinuBand have sufficient data to support systemic and ocular safety, whereas the remaining products have limited data to support their safety.
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