title: Melatonin secretion is impaired in women with preeclampsia and an abnormal circadian blood pressure rhythm.
abstract: Non-dipping circadian blood pressure (BP) is a common finding in preeclampsia, accompanied by adverse outcomes. Melatonin plays pivotal role in biological circadian rhythms. This study investigated the relationship between melatonin secretion and circadian BP rhythm in preeclampsia. Cases were women with preeclampsia treated between January 2006 and June 2007 in the University Hospital of Larissa. Volunteers with normal pregnancy, matched for chronological and gestational age, served as controls. Twenty-four hour ambulatory BP monitoring was applied. Serum melatonin and urine 6-sulfatoxymelatonin levels were determined in day and night time samples by enzyme-linked immunoassays. Measurements were repeated 2 months after delivery. Thirty-one women with preeclampsia and 20 controls were included. Twenty-one of the 31 women with preeclampsia were non-dippers. Compared to normal pregnancy, in preeclampsia there were significantly lower night time melatonin (48.4 ± 24.7 vs. 85.4 ± 26.9 pg/mL, p<0.001) levels. Adjustment for circadian BP rhythm status ascribed this finding exclusively to non-dippers (p<0.01). Two months after delivery, in 11 of the 21 non-dippers both circadian BP and melatonin secretion rhythm reappeared. In contrast, in cases with retained non-dipping status (n=10) melatonin secretion rhythm remained impaired: daytime versus night time melatonin (33.5 ± 13.0 vs. 28.0 ± 13.8 pg/mL, p=0.386). Urinary 6-sulfatoxymelatonin levels were, overall, similar to serum melatonin. Circadian BP and melatonin secretion rhythm follow parallel course in preeclampsia, both during pregnancy and, at least 2 months after delivery. Our findings may be not sufficient to implicate a putative therapeutic effect of melatonin, however, they clearly emphasize that its involvement in the pathogenesis of a non-dipping BP in preeclampsia needs intensive further investigation.
authors.affiliation: Faculty of Medicine, Department of Nephrology, School of Medicine, University of Thessaly , Larissa , Greece .
authors.forename: Sofia
authors.initials: S
authors.lastname: Bouchlariotou
authors.forename: Vassilios
authors.initials: V
authors.lastname: Liakopoulos
authors.forename: Myrto
authors.initials: M
authors.lastname: Giannopoulou
authors.forename: Spyridon
authors.initials: S
authors.lastname: Arampatzis
authors.forename: Theodoros
authors.initials: T
authors.lastname: Eleftheriadis
authors.forename: Peter R
authors.initials: PR
authors.lastname: Mertens
authors.forename: Elias
authors.initials: E
authors.lastname: Zintzaras
authors.forename: Ioannis E
authors.initials: IE
authors.lastname: Messinis
authors.forename: Ioannis
authors.initials: I
authors.lastname: Stefanidis
mesh_terms: D000328:Adult; D001794:Blood Pressure; D016022:Case-Control Studies; D002940:Circadian Rhythm; D005260:Female; D006801:Humans; D008550:Melatonin / Q000097:blood / Q000378:metabolism*; D049590:Postpartum Period / Q000502:physiology; D011225:Pre-Eclampsia / Q000097:blood / Q000503:physiopathology*; D011247:Pregnancy; D055815:Young Adult
chemical_list: D008550:Melatonin
keywords: Blood pressure; circadian rhythm; melatonin; preeclampsia