title: Increased expression of endothelin B receptor in static stretch exposed porcine mitral valve leaflets.
abstract: The aim of this study was to evaluate the effect of mechanical stretch on the expression of ET-1 and ET(A)- and ET(B)-receptors in porcine mitral valve leaflets. Leaflet segments from 10 porcine mitral valves were exposed to a static stretch load of 1.5 N for 3.5h in buffer at 37 degrees C together with matching control segments. Subsequently, the mRNA expression of ET-1, ET(A)-R and ET(B)-R was measured by real-time RT-PCR in the chordal insertion areas. The analyses showed an increased transcription of ET(B)-receptors in stretch-exposed leaflet segments compared to unstretched segments median 2.23 (quartiles 1.37 and 2.70) vs. median 1.56 (quartiles 1.38 and 2.17, P=0.03) whereas the mRNA expression of ET(A)-receptors (P=0.90) and ET-1 (P=0.51) remained unchanged. Stretch increased the expression of ET(B)-receptors in porcine mitral valve leaflets. The finding could lead to a better understanding of the pathogenesis of myxomatous mitral valve disease.
authors.affiliation: Department of Basic Animal and Veterinary Sciences, The Royal Veterinary and Agricultural University, 7 Groennegaardsvej, DK-1870 Frederiksberg, Copenhagen, Denmark. lgp@kvl.dk
authors.forename: L G
authors.initials: LG
authors.lastname: Pedersen
authors.forename: J
authors.initials: J
authors.lastname: Zhao
authors.forename: J
authors.initials: J
authors.lastname: Yang
authors.forename: P D
authors.initials: PD
authors.lastname: Thomsen
authors.forename: H
authors.initials: H
authors.lastname: Gregersen
authors.forename: J M
authors.initials: JM
authors.lastname: Hasenkam
authors.forename: M
authors.initials: M
authors.lastname: Smerup
authors.forename: H D
authors.initials: HD
authors.lastname: Pedersen
authors.forename: L H
authors.initials: LH
authors.lastname: Olsen
mesh_terms: D000818:Animals; D019332:Endothelin-1 / Q000096:biosynthesis / Q000235:genetics; D066298:In Vitro Techniques; D008944:Mitral Valve Insufficiency / Q000235:genetics / Q000378:metabolism / Q000662:veterinary*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D044022:Receptor, Endothelin A / Q000096:biosynthesis / Q000235:genetics; D044023:Receptor, Endothelin B / Q000096:biosynthesis* / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary; D018709:Statistics, Nonparametric; D013552:Swine; D013553:Swine Diseases / Q000235:genetics / Q000378:metabolism*
chemical_list: D019332:Endothelin-1; D012333:RNA, Messenger; D044022:Receptor, Endothelin A; D044023:Receptor, Endothelin B