Hypertension
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Angiotensin (Ang) II induces vascular injury in part by activating innate and adaptive immunity; however, the mechanisms are unclear. We investigated the role of interferon (IFN)-γ and interleukin (IL)-23 signaling. We infused Ang II into IFN-γ receptor (IFN-γR) knockout mice and wild-type controls, as well as into mice treated with neutralizing antibodies against IL-23 receptor and IL-17A. ⋯ Thus, IFN-γ blockade, but not IL-23 receptor antibody treatment, protects from Ang II-induced cardiac damage and electric remodeling. In the kidney, IFN-γ signaling acts in a cell type-specific manner. Glomerular filtration rate is preserved in the absence of the IFN-γR, whereas podocytes may require the IFN-γR in the presence of Ang II for normal integrity and function.
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Hypertensive transgenic (mRen2)27 rats with overexpression of the mRen2 gene have impaired baroreflex sensitivity for heart rate control and high nicotinamide adenine dinucleotide phosphate oxidase and kinase-to-phosphatase signaling activity in medullary tissue compared with normotensive Hannover Sprague-Dawley control rats. They also exhibit insulin resistance at a young age. To determine whether blocking angiotensin II actions, supplementing angiotensin-(1-7), or scavenging reactive oxygen species in brain differentially alters mean arterial pressure, baroreflex sensitivity, or metabolic function, while altering medullary signaling pathways in these animals, we compared intracerebroventricular infusions of the angiotensin II type 1 receptor antagonist candesartan (4 μg/5 μL/h), angiotensin-(1-7) (0.1 μg/5 μL/h), a reactive oxygen species scavenger tempol (25 μg/5 μL/h), or artificial cerebrospinal fluid (5 μL/h) for 2 weeks. ⋯ Tempol significantly reduced nicotinamide adenine dinucleotide phosphate oxidase activity in brain dorsal medullary tissue but had no effect on mean arterial pressure or autonomic function. Candesartan tended to reduce fat mass, but none of the treatments significantly altered indices of metabolic function or mitogen-activated protein kinase signaling pathways in dorsal medulla. Although additional dose response studies are necessary to determine the potential maximal effectiveness of each treatment, the current findings demonstrate that blood pressure and baroreflex function can be essentially normalized independently of medullary nicotinamide adenine dinucleotide phosphate oxidase or mitogen-activated protein kinase in hypertensive (mRen2)27 rats.
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Insomnia with objective short sleep duration appears to be a biologically more severe phenotype of the disorder. No longitudinal study to date has examined the association of this type of insomnia with incident hypertension using polysomnography. From a random, general population sample of 1741 adults of the Penn State Cohort, 1395 were followed-up after 7.5 years, and 786 did not have hypertension at baseline. ⋯ The risk for incident hypertension in poor sleepers with short sleep duration was significantly increased but became marginally significant after controlling for obesity (odds ratio, 1.6 [95% CI, 0.9-2.8]). Chronic insomnia with short sleep duration is associated with an increased risk for incident hypertension in a degree comparable to sleep-disordered breathing. Objective short sleep duration in insomnia may serve as a useful predictor of the biological severity of the disorder.
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Pretreatment with a phytoestrogen genistein has been shown to attenuate the development of pulmonary hypertension (PH). Because PH is not always diagnosed early, we examined whether genistein could also reverse preexisting established PH and prevent associated right heart failure (RHF). PH was induced in male rats by 60 mg/kg of monocrotaline. ⋯ These improvements in cardiopulmonary function and structure resulted in 100% survival by day 30. Genistein restored PH-induced downregulation of estrogen receptor-β expression in the right ventricle and lung. In conclusion, genistein therapy not only rescues preexisting severe PH but also prevents the progression of severe PH to RHF.