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Early Life Stress & Chronic Control of Blood Pressure

早期生活压力

基本信息

批准号：
8896033
负责人：
Analia Loria
金额：
$ 24.9万
依托单位：
UNIVERSITY OF KENTUCKY
依托单位国家：
美国
项目类别：
财政年份：
2013
资助国家：
美国
起止时间：
2013-09-23 至 2016-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8896033
关键词：
Acute Adipose tissue Adrenergic Agents Adult Aldosterone Angiotensin II Attenuated Behavioral Biochemical Biological Blood Pressure Blood Vessels Cardiovascular Diseases Cardiovascular system Caring Child Childhood Chronic Corticosterone Data Development Diabetes Mellitus Diet Disease Drops Environment Epidemic Event Excretory function Exposure to Fatty acid glycerol esters Filtration Functional disorder Ganglia Glomerular Filtration Rate Health Care Costs Human Hypertension Infusion procedures Investigation Kidney Kidney Diseases Leptin Life Life Stress Life Style Maintenance Mediating Mentors Minor Modeling Molecular Mothers Nerve Obesity Organ Outcome Pathway interactions Pediatrics Perinatal Phase Phenylephrine Physiological Plasma Predisposition Proteins Public Health Rattus Receptor Activation Receptor, Angiotensin, Type 1 Renal Tissue Renal function Renin Renin-Angiotensin-Aldosterone System Reporting Research Risk Factors Rodent Secondary to Stress System Techniques Testing Therapeutic Variant adrenergic blood pressure regulation desensitization in vivo maternal separation novel premature pressure programs pup receptor expression response stressor vasoconstriction

项目摘要

PROJECT SUMMARY Chronic adult diseases, such as hypertension, diabetes or obesity, may develop as a consequence of early life stress (ELS). Adverse childhood events are highly correlated with enhanced cardiovascular response to a secondary stressor, a "second hit". Maternal separation is an established model of chronic behavioral stress in rodents that involves separating pups from their mothers 3 hr/day from days 2-14 of life. Adult maternally separated (MS) rats show lower glomerular filtration rate under baseline conditions compared to control, un-separated littermates, with no difference in blood pressure. Interestingly, the phenylephrine-induced vasoconstriction in the kidney is attenuated but the drop in blood pressure elicited by ganglion blockade is greater in MS rats. These data suggest increased sympathetic activation in MS rats. In contrast, the acute pressor response to angiotensin II (AngII) is comparable between MS and control rats whereas MS rats show exaggerated chronic AngII-induced hypertension. Thus, our data suggest that ELS impairs the ability of the kidney to control blood pressure following a "second hit". Taken together, we hypothesize that rats exposed to MS display increased renal sympathetic nerve activity (RSNA), which enhances vascular tone in the kidneys and impairs the physiological regulation of blood pressure. Given the fact that RSNA can increase AngII type 1 (AT1) receptor expression, we speculate that increased baseline RSNA in MS rats results in increased renal AngII system components, predisposing these rats to cardiovascular disease. In an original approach to model the growing epidemic of children with extremely poor dietary lifestyles, we exposed the rats to a high fat diet (HFD) as a secondary stressor. Our data show a fat-induced increase in blood pressure develops in rats exposed to ELS compared to control rats. Furthermore, we observed increased plasma leptin, corticosterone, aldosterone and renin activity in MS rats. These compelling data support the hypothesis that ELS impairs maintenance of blood pressure homeostasis in response to "second hits" in adult life. The mentored phase will focus on the investigation of the RSNA and AT1-dependent mechanisms by which ELS exacerbates AngII-induced hypertension in adult rats, followed by the independent phase focused on the study of mechanisms by which ELS exacerbates blood pressure sensitivity to a HFD in adult rats. This novel proposal will investigate the following four aims: (1) to test the hypothesis that increased RSNA impairs renal capacity to control blood pressure in response to chronic AngII infusion in adult MS rats; (2) to test the hypothesis that exaggerated AT1 receptor activation increases renal vasoconstriction and reduces basal renal filtration capacity, enhancing AngII-induced hypertension in adult MS rats; (3) To test the hypothesis that MS increases sensitivity of blood pressure in response to a HFD through a renal mechanism; and (4) To test the hypothesis that HFD increases AngII in adipose tissue and induces AT1 dependent increase in blood pressure in MS rats.

项目总结