Central ANG-(1-7) infusion improves blood pressure regulation in antenatal betamethasone-exposed sheep and reveals sex-dependent effects on oxidative stress.

Authors:
Alexa S Hendricks
Alexa S Hendricks
Cardiovascular Sciences Center
Matthew J Lawson
Matthew J Lawson
University of Cincinnati College of Medicine
Jorge P Figueroa
Jorge P Figueroa
Wake Forest University School of Medicine
Raleigh | United States
Mark C Chappell
Mark C Chappell
Wake Forest University School of Medicine
United States
Debra I Diz
Debra I Diz
Wake Forest University School of Medicine
United States
Hossam A Shaltout
Hossam A Shaltout
Hypertension and Vascular Research Center

Am J Physiol Heart Circ Physiol 2019 Jun 5;316(6):H1458-H1467. Epub 2019 Apr 5.

Department of Surgery, Hypertension, and Vascular Research and the Cardiovascular Sciences Center, Wake Forest University School of Medicine , Winston-Salem, North Carolina.

Fetal exposure to betamethasone (BMX) as a consequence of glucocorticoid administration to women threatening premature delivery may lead to long-term deleterious effects on the cardiovascular system and dysregulation of blood pressure in exposed adults. Indeed, adult offspring of BMX sheep exhibit increased mean arterial pressure (MAP) and attenuated baroreflex sensitivity (BRS) that are associated with lower medullary and cerebrospinal fluid (CSF) angiotensin-(1-7) [(ANG-(1-7)] content. Thus we determined the effects of ANG-(1-7) supplementation in the CSF on MAP, BRS, blood pressure (BPV) and heart rate variability (HRV) in conscious animals. The peptide or artificial CSF (aCSF) was infused continuously into the lateral ventricle (intracerebroventricular) of 4-mo-old male and female BMX sheep for 2 wk. Analysis of data from males and females combined revealed that intracerebroventricular ANG-(1-7) significantly lowered MAP and heart rate and improved BRS as compared with baseline; intracerebroventricular aCSF did not change these indexes. Similar patterns were observed for altered hemodynamics and autonomic function produced by intracerebroventricular ANG-(1-7) in both sexes. Oxidative stress and MAP kinase (MAPK) activation were lower in tissues from the dorsomedial medulla (DMM) of ANG-(1-7)-treated males but were unchanged in the treated females, when assessed at the end of the treatment period. We conclude that in the face of ANG-(1-7) deficiency in CSF and medullary tissue in BMX sheep intracerebroventricular supplementation of ANG-(1-7) lowers MAP and restores the impaired autonomic function to a similar degree in both males and females; however, the attenuation of MAPK and oxidative stress within the DMM was evident only in males. We demonstrate that intracerebroventricular angiotensin-(1-7) [(ANG-(1-7)] treatment for 2 wk in antenatal betamethasone-exposed sheep provides beneficial effects on blood pressure and autonomic function. The physiological improvements are accompanied by an attenuation of oxidative stress in males but not females. The finding that ANG-(1-7) supplementation lowers blood pressure and restores the impaired autonomic function in a model of fetal programming previously shown to exhibit a deficiency in cerebrospinal fluid and brain tissue illustrates the potential for new therapeutic strategies for reducing cardiovascular dysfunction arising from prenatal events.

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Source
https://www.physiology.org/doi/10.1152/ajpheart.00497.2018
Publisher Site
http://dx.doi.org/10.1152/ajpheart.00497.2018DOI Listing
June 2019
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