Author/Editor		Žižek, Bogomir
Title		Endotelijska disfunkcija in ateroskleroza
Translated title		Endothelium dysfunction and atherosclerosis
Type		članek
Source		Med Razgl
Vol. and No.		Letnik 37, št. Suppl 3
Publication year		1998
Volume		str. 47-53
Language		slo
Abstract		The vascular endothelium, once believed to act solely as a mechanical barrier, is one of the body's most active paracrine and autocrine organs maintaining homeostasis between the blood and arterial walls. Endothelial cells release substances which profoundly affect vascular tone, blood flow and platelet function. The vasodilation substances include endothelium-derived relaxing factor and prostacylin (PGI2), which also have an antiplatelet effect, and act together with tissue plasminogen activator and protein S in preventing local procoagulant activity. Endothelin-1 is a potent vasoconstrictor peptide released from endothelial cells. Under certain conditions, the endothelium can also produce angiotensin II and cyclooxygenase-dependent contracting factor (PGH2). In normal arteries, the effects of NO appear to dominate. Hypercholesterolaemia, diabetes mellitus, smoking cigarettes, hypertension and atherosclerosis decrease the release of NO and increase that of endothelium-derived contracting factors. Recent investigations have indicated the importance of specific adhesion molecules that can be expressed by a functionally abnormal endothelium. Ultrasonographic methods are of great use for precise assessment of functional changes of endothelium in peripheral arteries which are manifested as reduced dilation response during reactive hyperaemia in patients with atherosclerotic vessel disease and in subjects with risk factors for atherosclerosis.
Summary		V žilnem endoteliju, za katerega so nekoč menili, da predstavlja le pregrado med tokom krvi in gladkimi mišičnimi celicami, poteka živahna sinteza številnih biološko pomembnih snovi, ki s svojim avtokrinim in parakrinim delovanjem vzdržujejo homeostazo med krvjo in žilno steno. Endotelijske celice igrajo aktivno vlogo pri uravnavanju tonusa žilne stene, pretoku krvi in funkciji trombocitov. Najpomembnejši vazoaktivni substanci sta endotelijski dejavnik z vazodilatatornim delovanjem in prostaciklin, ki skupaj s proteinom S in tkivnim aktivatorjem plazminogena zavirata na aktivacijo trombocitov in nastanek tromboze. Endotelin-1 je močan vazokonstriktorni peptid, ki ga izločajo endotelijske celice. V določenih pogojih lahko endotelij tvori angiotenzin-II in od ciklooksigenaze odvisni vazokonstriktorni prostaglandin. Zdi se, da v normalnih razmerah prevladuje vpliv NO na funkcijo žilne stene. Pri bolezenskih stanjih, kot so hiperholesterolemija, hipertenzija, sladkorna bolezen, kajenje in ateroskleroza, se zmanjša izločanje NO, poveča pa tvorba endotelijskih dejavnikov z vazokonstriktornim delovanjem. Novejše raziskave so odkrile pomen in vlogo pojačanega izražanja adhezijskih molekul na površini funkcijsko okvarjenega endotelija. Funkcijske spremembe perifernih arterij, ki se kažejo v nesposobnosti razširitve arterije med reaktivno hiperemijo, lahko natančno določimo z ultrazvočno preiskavo tako, da izmerimo pretok krvi in od povečanja pretoka odvisno dilatacijo preiskovane arterije, ki je pri bolnikih z aterosklerotičnimi spremembami na žilju in prisotnosti dejavnikov tveganja zmanjšana.
Descriptors		ENDOTHELIUM, VASCULAR ATHEROSCLEROSIS ENDOTHELIUM-DERIVED RELAXING FACTOR ENDOTHELIN-1 COAGULANTS