Cardiovascular disease is considered a probable risk factor of particulate matter (PM)-related mortality and morbidity. It was hypothesized that rats with hereditary systemic hypertension and underlying cardiac disease would be more susceptible than healthy normotensive rats to pulmonary injury from inhaled residual oil fly ash (ROFA) PM. Eight spontaneously hypertensive (SH) and eight normotensive Wistar-Kyoto (WKY) rats (12-13 weeks old) were implanted with radiotelemetry transmitters on Day -10 for measurement of electrocardiographic (ECG) waveforms. These and other nonimplanted rats were exposed to filtered air or ROFA (containing leachable toxic levels of metals) on Day 0 by nose-only inhalation (ROFA, 15 mg/m(3) x 6 h/day x 3 days). ECGs were monitored during both exposure and nonexposure periods. At 0 or 18 h post-ROFA exposure, rats were assessed for airway hyperreactivity, pulmonary and cardiac histological lesions, bronchoalveolar lavage fluid (BALF) markers of lung injury, oxidative stress, and cytokine gene expression. Comparisons were made in two areas: (1) underlying cardiopulmonary complications of control SH rats in comparison to control WKY rats; and (2) ROFA-induced cardiopulmonary injury/inflammation and oxidative burden. With respect to the first area, control air-exposed SH rats had higher lung and left ventricular weights when compared to age-matched WKY rats. SH rats had hyporeactive airways to acetylcholine challenge. Lung histology revealed the presence of activated macrophages, neutrophils, and hemorrhage in control SHrats. Consistently, levels of BALF protein, macrophages, neutrophils, and red blood cells were also higher in SH rats. Thiobarbituric acid-reactive material in the BALF of air-exposed SH rats was significantly higher than that of WKY rats. Lung inflammation and lesions were mirrored in the higher basal levels of pulmonary cytokine mRNA expression. Cardiomyopathy and monocytic cell infiltration were apparent in the left ventricle of SH rats, along with increased cytokine expression. ECG demonstrated a depressed ST segment area in SH rats. With regard to the second area of comparison (ROFA-exposed rats), pulmonary histology indicated a slightly exacerbated pulmonary lesions including inflammatory response to ROFA in SH rats compared to WKY rats and ROFA-induced increases in BALF protein and albumin were significantly higher in SH rats than in WKY rats. In addition, ROFA caused an increase in BALF red blood cells in SH rats, indicating increased hemorrhage in the alveolar parenchyma. The number of alveolar macrophages increased more dramatically in SH rats following ROFA exposure, whereas neutrophils increased similarly in both strains. Despite greater pulmonary injury in SH rats, ROFA-induced increases in BALF GSH, ascorbate, and uric acid were attenuated when compared to WKY rats. ROFA inhalation exposure was associated with similar increases in pulmonary mRNA expression of IL-6, cellular fibronectin, and glucose-6-phosphate dehydrogenase (relative to that of beta-actin) in both rat strains. The expression of MIP-2 was increased in WKY but attenuated in SH rats. Thus, SH rats have underlying cardiac and pulmonary complications. When exposed to ROFA, SH rats exhibited exacerbated pulmonary injury, an attenuated antioxidant response, and acute depression in ST segment area of ECG, which is consistent with a greater susceptibility to adverse health effects of fugitive combustion PM. This study shows that the SH rat is a potentially useful model of genetically determined susceptibility with pulmonary and cardiovascular complications.
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http://dx.doi.org/10.1006/taap.2000.8899 | DOI Listing |
Receptors for the vasoactive adipokine apelin, termed APJ receptors, are G-protein-coupled receptors and are widely expressed throughout the cardiovascular system. APJ receptors can also signal via G-protein-independent pathways, including G-protein-coupled-receptor kinase 2 (GRK2), which inhibits nitric oxide synthase (eNOS) activity and nitric oxide (NO) production in endothelial cells. Apelin causes endothelium-dependent, NO-mediated relaxation of coronary arteries from normotensive animals, but the effects of activating APJ receptor signaling pathways in hypertensive coronary arteries are largely unknown.
View Article and Find Full Text PDFNan Fang Yi Ke Da Xue Xue Bao
January 2025
College of Integrative Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou 350122, China.
Objectives: To explore the mechanism of Granules (QDG) for alleviating brain damage in spontaneously hypertensive rats (SHRs).
Methods: Twelve 5-week-old SHRs were randomized into SHR control group and SHR+QDG group treated with QDG by gavage at the daily dose of 0.9 g/kg for 12 weeks.
Background: Prostaglandin E (PGE) in the rostral ventrolateral medulla (RVLM) has been recognized as a pivotal pressor substance in hypertension, yet understanding of its effects and origins in the RVLM remains largely elusive. This study aimed to elucidate the pivotal enzymes and molecular mechanisms underlying PGE synthesis induced by central Ang II (angiotensin II) and its implications in the heightened oxidative stress and sympathetic outflow in hypertension.
Methods And Results: RVLM microinjections of PGE and Tempol were administered in Wistar-Kyoto rats.
CNS Neurosci Ther
January 2025
Hypertension Center, The Second Hospital & Clinical Medical School, Lanzhou University, Lanzhou, Gansu, China.
Aims: We aimed to investigate the role of Rnf40 in hypertension-induced cerebrovascular endothelial barrier dysfunction and cognitive impairment.
Methods: We employed microarray data analysis and integrated bioinformatics databases to identify a novel E3 ligase, Rnf40, that targets Parkin. To understand the role of RNF40 in hypertension-induced cerebrovascular endothelial cell damage, we used pAAV-hFLT1-MCS-EGFP-3×Flag-mir30shRnf40 to establish an Rnf40-deficient model in spontaneously hypertensive rats (SHRs).
Hypertension
January 2025
Cardiorenal Research Laboratory, Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN. (Xiaoyu Ma, J.C.M., D.G.M., Xiao Ma, Y.Z., S.P., Y.W., S.J.S., J.C.B.).
Background: Cardiomyocyte oxidative stress significantly contributes to the progression of hypertension-induced heart failure, highlighting the need for targeted therapies. We developed a novel peptide, NPA7, that coactivates the GC-A (guanylyl cyclase A)/cGMP and MasR (Mas receptor)/cAMP pathway. This study aimed to test NPA7's ability to inhibit oxidative stress by modulating the p62-KEAP1 (Kelch-like ECH-associated protein 1)-NRF2 (nuclear factor erythroid 2-related factor 2) pathway in human cardiomyocytes (HCMs) and a rat model of hypertension.
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