Vascular and cardiac impairments in rats inhaling ozone and diesel exhaust particles.

BACKGROUND: Mechanisms of cardiovascular injuries from exposure to gas and particulate air pollutants are unknown. OBJECTIVE: We sought to determine whether episodic exposure of rats to ozone or diesel exhaust particles (DEP) causes differential cardiovascular impairments that are exacerbated by ozone plus DEP. METHODS AND RESULTS: Male Wistar Kyoto rats (10-12 weeks of age) were exposed to air, ozone (0.4 ppm), DEP (2.1 mg/m(3)), or ozone (0.38 ppm) + DEP (2.2 mg/m(3)) for 5 hr/day, 1 day/week for 16 weeks, or to air, ozone (0.51 or 1.0 ppm), or DEP (1.9 mg/m(3)) for 5 hr/day for 2 days. At the end of each exposure period, we examined pulmonary and cardiovascular biomarkers of injury. In the 16-week study, we observed mild pulmonary pathology in the ozone, DEP, and ozone + DEP exposure groups, a slight decrease in circulating lymphocytes in the ozone and DEP groups, and decreased platelets in the DEP group. After 16 weeks of exposure, mRNA biomarkers of oxidative stress (hemeoxygenase-1), thrombosis (tissue factor, plasminogen activator inhibitor-1, tissue plasminogen activator, and von Willebrand factor), vasoconstriction (endothelin-1, endothelin receptors A and B, endothelial NO synthase) and proteolysis [matrix metalloprotease (MMP)-2, MMP-3, and tissue inhibitor of matrix metalloprotease-2] were increased by DEP and/or ozone in the aorta, but not in the heart. Aortic LOX-1 (lectin-like oxidized low-density lipoprotein receptor-1) mRNA and protein increased after ozone exposure, and LOX-1 protein increased after exposure to ozone + DEP. RAGE (receptor for advanced glycation end products) mRNA increased in the ozone + DEP group. Exposure to ozone or DEP depleted cardiac mitochondrial phospholipid fatty acids (DEP > ozone). The combined effect of ozone and DEP exposure was less pronounced than exposure to either pollutant alone. Exposure to ozone or DEP for 2 days (acute) caused mild changes in the aorta. CONCLUSIONS: In animals exposed to ozone or DEP alone for 16 weeks, we observed elevated biomarkers of vascular impairments in the aorta, with the loss of phospholipid fatty acids in myocardial mitochondria. We conclude that there is a possible role of oxidized lipids and protein through LOX-1 and/or RAGE signaling.

Pheochromocytoma induced hypertension.

Pheochromocytoma (Pheo) is a rare tumor that develops in the core of a chromaffin cell. This article will focus on pheochromocytoma and its affect on the heart. Because the signs and symptoms of a pheochromocytoma are those of the sympathetic nervous system, this tumor is hard to detect and might not be considered early on. In addition, there are many common deferential diagnoses that may lead to a delay of the correct diagnosis of a pheochromocytoma. Uncontrollable hypertension is one of the primary effects of pheochromocytoma. A severe increase in blood pressure (hypertensive crisis) may occur and this can be a life threatening condition that leads to stroke or arrhythmias. African-Americans are disproportionately affected by hypertension and they often go undiagnosed because of a lack of resources or access to care. This tumor is difficult to detect and its effects often mimic many other diagnoses, which often leads to this tumor being a late consideration. The long-term effects of a pheochromocytoma can lead to damage to the heart muscle, congestive heart failure (CHF), increased risk of diabetes, and even death. Nurses need to be aware of the key signs and symptoms of a pheochromocytoma, and to know when testing for this tumor what symptoms should be considered. Patients who suffer from a diagnosis of this tumor need a lot of emotional support and they must follow a strict diet and medication regimen. Nurses can play a vital role in raising awareness in our community about this tumor as well as being a patient advocate.