Respiratory diseases linked with high blood pressure in lungs: MU researcher examines underlying conditions causing pulmonary hypertension - Science Daily
Respiratory diseases linked with high blood pressure in lungs: MU researcher examines underlying conditions causing pulmonary hypertension - Science Daily |
| Posted: 16 Oct 2019 11:00 AM PDT Pulmonary hypertension is a type of high blood pressure that affects the lungs of both animals and people. When tiny vessels in the lungs become narrowed or blocked, it becomes harder for blood to flow through and can cause the heart to weaken or fail. Now, researchers at the University of Missouri have found that identifying respiratory diseases causing pulmonary hypertension can lead to improved health outcomes. Carol Reinero, professor of small animal internal medicine in the College of Veterinary Medicine, was a member of a team that studied 47 dogs with pulmonary hypertension caused by respiratory disease. The goal was to better characterize the types of underlying respiratory disorders in dogs causing high blood pressure in their lungs and to identify prognostic variables. "Understanding the diseases that contribute to pulmonary hypertension can lead to more tailored therapy approaches and help identify which medications are likely to be most beneficial," Reinero said. "As many of these dogs have multiple issues, a thorough evaluation is needed to address the underlying problems causing the pulmonary hypertension." Reinero collaborated with veterinary cardiologists Kelly Wiggen and Stacey Leach, who performed an echocardiogram -- an ultrasound of the heart -- on the dogs in the study to identify pulmonary hypertension. "This is a great example of interdisciplinary teamwork, as MU's College of Veterinary Medicine has both the specialized expertise and technical abilities to conduct comprehensive evaluations that ultimately lead to more thorough diagnoses and individualized treatment plans," Reinero said. "We see people bring in their dogs from all over the country, which reflects our strength in the area of respiratory medicine." In both animals and humans, untreated pulmonary hypertension can lead to death. Recent research by the same investigators found that tadalafil, the active drug in Cialis, effectively treats pulmonary hypertension in dogs by dilating pulmonary vessels. The medicine, which is consumed by dogs in the form of a pill, only needs to be taken once a day and was the sole predictor of survival in the study. "Our goal is to make a difference by improving the quality of care for animals," Reinero said. "Doing clinically-relevant research means not just helping individual dogs, but also finding new knowledge that other vets can ultimately use to improve the quality of care for dogs worldwide." Story Source: Materials provided by University of Missouri-Columbia. Note: Content may be edited for style and length.  |
| Posted: 09 Oct 2019 12:00 AM PDT Loss of a hormone called secretin (SCT) induces hypertension, scarring, and structural alterations in the heart and lungs, a study in mice reports. The study "Loss of secretin results in systemic and pulmonary hypertension with cardiopulmonary pathologies in mice" was published in the journal Nature Scientific Reports, and led by a team from Hong Kong. SCT is released by cells in the intestine and the brain, and its receptors are found at high levels in both the heart and lungs. Prior studies showed that SCT reduces blood pressure in the heart, increases cardiac blood flow, and regulates water and salt balance, among other mechanisms. Blood serum levels of SCT are also known to be markedly lower in people with congestive heart failure. However, "no studies have clearly shown the significance of SCT in these systems and explained how SCT plays a role in regulating blood pressure," the researchers wrote. The team investigated the severity of SCT's loss to the heart and lungs using mice in which the gene coding for secretin had been deleted. Compared to normal mice serving as controls, mice with no SCT showed increased blood pressure. This was accompanied by changes in the heart's chambers, namely right ventricular hypertrophy (enlargement) and fibrosis, or scarring. The heart's left ventricle was smaller than in control mice. Loss of secretin also led to pulmonary arterial hypertension (PAH), as shown by increased right ventricular systolic pressure in mice without SCT compared to control mice. This increase was detected as early as 3 months of age, and maintained until the age of 12 months. Right ventricular enlargement, another hallmark of PAH, was also seen in 3-month-old mice with SCT deficiency. Animals with no SCT also showed changes in lung tissue compared to the controls; namely, a significant increase in pulmonary artery thickness, severe structural alterations in blood vessels (vascular remodeling), and inflammation. Other changes associated with a complete lack of SCT included lower serum levels of nitric oxide (NO) and vascular endothelial growth factor (VEGF). In line with the previously shown role of VEGF in stimulating NO production to widen blood vessels, this suggests that a lack of SCT could lead to persistent vasoconstriction and elevated blood pressure, the researchers said. In contrast, levels of aldosterone were higher than normal in plasma and the heart of mice without SCT, as seen in people with congestive heart failure. The scientists then tested whether administration of SCT up to three months could effectively treat hypertension. Three-month-old mice lacking SCT were given this hormone (at 2.5 nmol/kg/day) via a pump into the abdomen. After three months, blood levels of SCT in these animals were similar to those of control mice. Mice given SCT also showed significantly reduced thickening of heart and lung arteries, as well as less cardiac scarring and inflammation. Overall, the findings suggest that "SCT can be an essential hormone for the cardiovascular and pulmonary systems in humans, since SCT deficiency can result in pulmonary and systemic hypertension in mice," the researchers wrote. Measuring SCT levels "can provide interesting information, such as whether SCT deficiency has a role in pulmonary and systemic hypertension in humans," they added.  Patricia holds her Ph.D. in Cell Biology from University Nova de Lisboa, and has served as an author on several research projects and fellowships, as well as major grant applications for European Agencies. She also served as a PhD student research assistant in the Laboratory of Doctor David A. Fidock, Department of Microbiology & Immunology, Columbia University, New York. × Patricia holds her Ph.D. in Cell Biology from University Nova de Lisboa, and has served as an author on several research projects and fellowships, as well as major grant applications for European Agencies. She also served as a PhD student research assistant in the Laboratory of Doctor David A. Fidock, Department of Microbiology & Immunology, Columbia University, New York. Latest Posts  |
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