PMID- 26104664 OWN - NLM STAT- MEDLINE DCOM- 20160304 LR - 20211203 IS - 2047-783X (Electronic) IS - 0949-2321 (Print) IS - 0949-2321 (Linking) VI - 20 IP - 1 DP - 2015 Jun 24 TI - Rapamycin impairs endothelial cell function in human internal thoracic arteries. PG - 59 LID - 10.1186/s40001-015-0150-4 [doi] LID - 59 AB - BACKGROUND: Definitive fate of the coronary endothelium after implantation of a drug-eluting stent remains unclear, but evidence has accumulated that treatment with rapamycin-eluting stents impairs endothelial function in human coronary arteries. The aim of our study was to demonstrate this phenomenon on functional, morphological and biochemical level in human internal thoracic arteries (ITA) serving as coronary artery model. METHODS: After exposure to rapamycin for 20 h, functional activity of ITA rings was investigated using the organ bath technique. Morphological analysis was performed by scanning electron microscopy and evaluated by two independent observers in blinded fashion. For measurement of endothelial nitric oxide synthase (eNOS) release, mammalian target of rapamycin (mTOR) and protein kinase B (PKB) (Akt) activation, Western blotting on human mammary epithelial cells-1 and on ITA homogenates was performed. RESULTS: Comparison of the acetylcholine-induced relaxation revealed a significant concentration-dependent decrease to 66 +/- 7 % and 36 +/- 7 % (mean +/- SEM) after 20-h incubation with 1 and 10 muM rapamycin. Electron microscopic evaluation of the endothelial layer showed no differences between controls and samples exposed to 10 muM rapamycin. Western blots after 20-h incubation with rapamycin (10 nM-1 muM) revealed a significant and concentration-dependent reduction of p (Ser 1177)-eNOS (down to 38 +/- 8 %) in human mammary epithelial cells (Hmec)-1. Furthermore, 1 muM rapamycin significantly reduced activation of p (Ser2481)-mTOR (58 +/- 11 %), p (Ser2481)-mTOR (23 +/- 4 %) and p (Ser473)-Akt (38 +/- 6 %) in ITA homogenates leaving Akt protein levels unchanged. CONCLUSIONS: The present data suggests that 20-h exposure of ITA rings to rapamycin reduces endothelium-mediated relaxation through down-regulation of Akt-phosphorylation via the mTOR signalling axis within the ITA tissue without injuring the endothelial cell layer. FAU - Reineke, David C AU - Reineke DC AD - Department of Cardiovascular Surgery, University Hospital Berne, Bern, CH-3010, Switzerland. FAU - Muller-Schweinitzer, Else AU - Muller-Schweinitzer E AD - Department of Cardiac Surgery, University Hospital Basel, Spitalstrasse 21, Basel, CH-4031, Switzerland. AD - Department of Biomedicine, University Basel, Basel, CH-4031, Switzerland. FAU - Winkler, Bernhard AU - Winkler B AD - Department of Cardiovascular Surgery, University Hospital Berne, Bern, CH-3010, Switzerland. AD - Department of Biomedicine, University Basel, Basel, CH-4031, Switzerland. FAU - Kunz, Donatina AU - Kunz D AD - Department of Cardiac Surgery, University Hospital Basel, Spitalstrasse 21, Basel, CH-4031, Switzerland. AD - Department of Biomedicine, University Basel, Basel, CH-4031, Switzerland. FAU - Konerding, Moritz A AU - Konerding MA AD - Department of Anatomy, Johannes Gutenberg-University, Mainz, 55099, Germany. FAU - Grussenmeyer, Thomas AU - Grussenmeyer T AD - Department of Cardiac Surgery, University Hospital Basel, Spitalstrasse 21, Basel, CH-4031, Switzerland. AD - Department of Biomedicine, University Basel, Basel, CH-4031, Switzerland. FAU - Carrel, Thierry P AU - Carrel TP AD - Department of Cardiovascular Surgery, University Hospital Berne, Bern, CH-3010, Switzerland. FAU - Eckstein, Friedrich S AU - Eckstein FS AD - Department of Cardiac Surgery, University Hospital Basel, Spitalstrasse 21, Basel, CH-4031, Switzerland. AD - Department of Biomedicine, University Basel, Basel, CH-4031, Switzerland. FAU - Grapow, Martin T R AU - Grapow MT AD - Department of Cardiac Surgery, University Hospital Basel, Spitalstrasse 21, Basel, CH-4031, Switzerland. martin.grapow@usb.ch. AD - Department of Biomedicine, University Basel, Basel, CH-4031, Switzerland. martin.grapow@usb.ch. LA - eng PT - Journal Article DEP - 20150624 PL - England TA - Eur J Med Res JT - European journal of medical research JID - 9517857 RN - 0 (Anti-Bacterial Agents) RN - EC 1.14.13.39 (Nitric Oxide Synthase Type III) RN - EC 2.7.11.1 (Proto-Oncogene Proteins c-akt) RN - EC 2.7.11.1 (TOR Serine-Threonine Kinases) RN - W36ZG6FT64 (Sirolimus) SB - IM MH - Aged MH - Aged, 80 and over MH - Anti-Bacterial Agents/adverse effects/*pharmacology MH - Endothelial Cells/*drug effects/metabolism/ultrastructure MH - Endothelium, Vascular/*drug effects/metabolism/ultrastructure MH - Female MH - Humans MH - Male MH - Middle Aged MH - Nitric Oxide Synthase Type III/genetics/metabolism MH - Proto-Oncogene Proteins c-akt/genetics/metabolism MH - Sirolimus/adverse effects/*pharmacology MH - TOR Serine-Threonine Kinases/genetics/metabolism MH - Thoracic Arteries/cytology/*drug effects PMC - PMC4502526 EDAT- 2015/06/25 06:00 MHDA- 2016/03/05 06:00 PMCR- 2015/06/24 CRDT- 2015/06/25 06:00 PHST- 2015/02/10 00:00 [received] PHST- 2015/06/17 00:00 [accepted] PHST- 2015/06/25 06:00 [entrez] PHST- 2015/06/25 06:00 [pubmed] PHST- 2016/03/05 06:00 [medline] PHST- 2015/06/24 00:00 [pmc-release] AID - 10.1186/s40001-015-0150-4 [pii] AID - 150 [pii] AID - 10.1186/s40001-015-0150-4 [doi] PST - epublish SO - Eur J Med Res. 2015 Jun 24;20(1):59. doi: 10.1186/s40001-015-0150-4.