title: Indapamide lowers blood pressure by increasing production of epoxyeicosatrienoic acids in the kidney.
abstract: Diuretics are widely used in the treatment of hypertension, although the precise mechanisms remain unknown. Epoxyeicosatrienoic acids (EETs), cytochrome P450 (P450) epoxygenase metabolites of arachidonic acid, play critical roles in regulation of blood pressure. The present study was carried out to investigate whether EETs participate in the antihypertensive effect of thiazide diuretics [hydrochlorothiazide (HCTZ)] and thiazide-like diuretics (indapamide). Male spontaneously hypertensive rats (SHRs) were treated with indapamide or HCTZ for 8 weeks. Systolic blood pressure, measured via tail-cuff plethysmography and confirmed via intra-arterial measurements, was significantly decreased in indapamide- and HCTZ-treated SHRs compared with saline-treated SHRs. Indapamide increased kidney CYP2C23 expression, decreased soluble epoxide hydrolase expression, increased urinary and renovascular 11,12- and 14,15-EETs, and decreased production of 11,12- and 14,15-dihydroxyeicosatrienoic acids in SHRs. No effect on expression of CYP4A1 or CYP2J3, or on 20-hydroxyeicosatetraenoic acid production, was observed, suggesting indapamide specifically targets CYP2C23-derived EETs. Treatment of SHRs with HCTZ did not affect the levels of P450s or their metabolites. Increased cAMP activity and protein kinase A expression were observed in the renal microvessels of indapamide-treated SHRs. Indapamide ameliorated oxidative stress and inflammation in renal cortices by down-regulating the expression of p47phox, nuclear factor-κB, transforming growth factor-β1, and phosphorylated mitogen-activated protein kinase. Furthermore, the p47phox-lowering effect of indapamide in angiotensin II-treated rat mesangial cells was partially blocked by the presence of N-(methylsulfonyl)-2-(2-propynyloxy)-benzenehexanamide (MS-PPOH) or CYP2C23 small interfering RNA. Together, these results indicate that the hypotensive effects of indapamide are mediated, at least in part, by the P450 epoxygenase system in SHRs, and provide novel insights into the blood pressure-lowering mechanisms of diuretics.
authors.affiliation: Department of Internal Medicine and The Institute of Hypertension, Tongji Hospital, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, People’s Republic of China.
authors.forename: Fei
authors.initials: F
authors.lastname: Ma
authors.forename: Fan
authors.initials: F
authors.lastname: Lin
authors.forename: Chen
authors.initials: C
authors.lastname: Chen
authors.forename: Jennifer
authors.initials: J
authors.lastname: Cheng
authors.forename: Darryl C
authors.initials: DC
authors.lastname: Zeldin
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.forename: Dao Wen
authors.initials: DW
authors.lastname: Wang
mesh_terms: D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects*; D000242:Cyclic AMP / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D000090762:Cytochrome P-450 CYP2J2; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D004851:Epoxide Hydrolases / Q000378:metabolism; D006852:Hydrochlorothiazide / Q000494:pharmacology; D006893:Hydroxyeicosatetraenoic Acids / Q000096:biosynthesis* / Q000378:metabolism; D007190:Indapamide / Q000494:pharmacology*; D007249:Inflammation / Q000378:metabolism; D007668:Kidney / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D019255:NADPH Oxidases / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D049993:Sodium Chloride Symporter Inhibitors / Q000494:pharmacology; D053773:Transforming Growth Factor beta1 / Q000378:metabolism
chemical_list: D000959:Antihypertensive Agents; C000717351:Cyp2c23 protein, rat; D006893:Hydroxyeicosatetraenoic Acids; D016328:NF-kappa B; D049993:Sodium Chloride Symporter Inhibitors; D053773:Transforming Growth Factor beta1; D006852:Hydrochlorothiazide; C055987:20-hydroxy-5,8,11,14-eicosatetraenoic acid; D003577:Cytochrome P-450 Enzyme System; D000242:Cyclic AMP; C106098:Cyp2j3 protein, rat; D000090762:Cytochrome P-450 CYP2J2; D019255:NADPH Oxidases; C060505:neutrophil cytosolic factor 1; D017868:Cyclic AMP-Dependent Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; D004851:Epoxide Hydrolases; D007190:Indapamide