High altitude cattle and comparative medicine

A recent article in the New York Times is a reminder of the potential for new approaches to comparative medicine outside of the typical research laboratory. For years, veterinary researchers have studied the effect of high altitude on cattle grazing in mountainous areas of New Mexico and elsewhere. These studies have revealed important findings about the chronic effect of hypoxia on the cardiovascular system, including insight into the condition of hypoxic pulmonary hypertension that is an important disease in humans. The researchers have also been able to study the effect of genetic susceptibility on these physiologic responses, and to develop clinical approaches for early diagnosis of altitude illness. The recent research reported in the Times actually builds on studies of high altitude cattle in Colorado and other parts of the Southwestern US that have gone on over the past 100 years. And while we have learned a lot about human pulmonary hypertension (a disease that develops in individuals with sleep apnea and other hypoxic conditions) from “Brisket disease” in cattle, there are also preventive lessons to learn from animals that are evolutionarily adapted to high altitude, such as certain types of llamas, rodents, and yaks. These adaptations can involve not only much thinner blood vessels in the lungs, but also a lack of the response to low oxygen that is seen in cows and persons who develop pulmonary hypertension.  These findings reinforce the fact that there is much to learn from studies of naturally occurring animal populations that can influence both human medicine, veterinary medicine, and our understanding of the effects of environmental factors on health.