Increased cytochrome P4502E1 expression and altered hydroxyeicosatetraenoic acid formation mediate diabetic vascular dysfunction: rescue by guanylyl-cyclase activation.
OBJECTIVE
We investigated the mechanisms underlying vascular endothelial and contractile dysfunction in diabetes as well as the effect of HMR1766, a novel nitric oxide (NO)-independent activator of soluble guanylyl cyclase (sGC).


METHODS
Two weeks after induction of diabetes by streptozotocin, Wistar rats received either placebo or HMR1766 (10 mg/kg twice daily) for another 2 weeks; thereafter, vascular function was assessed.


RESULTS
Endothelial function and contractile responses were significantly impaired, while vascular superoxide formation was increased in the aortae from diabetic versus healthy control rats. Using RNA microarrays, cytochrome P4502E1 (CYP2E1) was identified as the highest upregulated gene in diabetic aorta. CYP2E1 protein was significantly increased (16-fold) by diabetes, leading to a reduction in levels of the potent vasoconstrictor 20-hydroxy-eicosatetraenoic acid (20-HETE). Induction of CYP2E1 expression in healthy rats using isoniazide mimicked the diabetic noncontractile vascular response while preincubation of aortae from STZ-diabetic rats in vitro with 20-HETE rescued contractile function. Chronic treatment with the sGC activator HMR1766 improved NO sensitivity and endothelial function, reduced CYP2E1 expression and superoxide formation, enhanced 20-HETE levels, and reversed the contractile deficit observed in the diabetic rats that received placebo.


CONCLUSIONS
Upregulation of CYP2E1 is essentially involved in diabetic vascular dysfunction. Chronic treatment with the sGC activator HMR1766 reduced oxidative stress, decreased CYP2E1 levels, and normalized vasomotor function in diabetic rats.
Department of Internal Medicine I, University Hospital Würzburg, Julius-Maximilians-University Würzburg, Würzburg, Germany. a.schaefer@medizin.uni-wuerzburg.de
Andreas
A
Schäfer
Paolo
P
Galuppo
Daniela
D
Fraccarollo
Christian
C
Vogt
Julian D
JD
Widder
Julia
J
Pfrang
Piet
P
Tas
Eduardo
E
Barbosa-Sicard
Hartmut
H
Ruetten
Georg
G
Ertl
Ingrid
I
Fleming
Johann
J
Bauersachs
D000818:Animals; D001013:Aorta, Thoracic / Q000378:metabolism / Q000503:physiopathology; D019392:Cytochrome P-450 CYP2E1 / Q000235:genetics*; D003921:Diabetes Mellitus, Experimental / Q000188:drug therapy; D003925:Diabetic Angiopathies / Q000201:enzymology / Q000235:genetics; D015971:Gene Expression Regulation, Enzymologic; D006162:Guanylate Cyclase / Q000235:genetics* / Q000378:metabolism* / Q000627:therapeutic use; D006801:Humans; D006893:Hydroxyeicosatetraenoic Acids / Q000096:biosynthesis*; D035683:MicroRNAs / Q000235:genetics; D020411:Oligonucleotide Array Sequence Analysis; D018384:Oxidative Stress / Q000187:drug effects; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism; D013449:Sulfonamides / Q000627:therapeutic use*; D013481:Superoxides / Q000378:metabolism; D015854:Up-Regulation; D014664:Vasodilation / Q000187:drug effects; D062367:ortho-Aminobenzoates / Q000627:therapeutic use*
D006893:Hydroxyeicosatetraenoic Acids; D035683:MicroRNAs; D017382:Reactive Oxygen Species; D013449:Sulfonamides; D062367:ortho-Aminobenzoates; D013481:Superoxides; C055987:20-hydroxy-5,8,11,14-eicosatetraenoic acid; D019392:Cytochrome P-450 CYP2E1; D006162:Guanylate Cyclase; C515616:5-chloro-2-(5-chlorothiophene-2-sulfonylamino)-N-(4-(morpholine-4-sulfonyl)phenyl)benzamide