Researchers confirmed that decreased oxygen supply to tissues induces cardiovascular dysfunction

A group of researchers analyzed Chronic intermittent hypobaric hypoxia
(CIHH) and confirmed that it induces cardiovascular dysfunction in a shift-based model. work at high altitude.

Lorenzo Palma, Science in Chile.- Every day, more than 80 million people are inhabiting areas located above 2,500 meters above sea level (masl), facing the effects of the decrease in atmospheric pressure and the consequent reduction in the relative partial pressure of oxygen. This condition is known as hypobaric hypoxia.

In certain activities such as mining, astronomy and customs, people
face chronic hypobaric hypoxia intermittently due to shifts
of work they do. However, it has not yet been determined with certainty
exact impact this has on cardiovascular structure and function, as it
these aspects are not fully characterized.

To advance knowledge, a research led by Dr. Emilio
Herrera, belonging to the Vascular Function and Reactivity Laboratory, Program
Physiopathology, ICBM, Faculty of Medicine, University of Chile, carried out a
exhaustive study in 12 adult rats, which was published in the scientific journal Life
Sciences.

Adult rats simulated work shifts at high altitudes,
considering altitudes of 4,600 masl and low altitudes of 760 masl. During the
investigation, various tests were performed, including echocardiography in the
animals. Dr. Emilio Herrera said, “Our findings highlight the impact of
chronic intermittent hypobaric hypoxia on cardiovascular function, and highlight the
importance of performing periodic evaluations of the cardiovascular system in
workers who work at high altitudes.

Conditions such as altitude sickness, fatigue, pulmonary arterial hypertension, edema
high-altitude stroke, hemorrhage, and stroke, can
occur as a consequence of acute exposure to altitude.
What the researchers were able to confirm is that CIHH causes a reduction
of the contractile function of the left ventricle associated with ventricular remodeling and an increase in the prooxidant state.

Furthermore, these changes were associated with a lower vasodilator response in the femoral arteries, related to dependent and independent impairment of nitric oxide (NO). “This study offers a better overview of the cardiovascular effects of CIHH, serving as a point reference for future biomedical analyzes of
oxidative stress markers and other mechanistic studies that may
help us give a prognosis of cardiovascular health”, explained the academic of the
ICBM of the University of Chile.

“The highlight of the results is that the animals that simulated shifts of
work at height showed a cardiac alteration associated with a decrease in
the vasodilation capacity of the arteries that supply different areas of the
body. In other words, the entire cardiovascular system is affected,” explained the
investigator.

On the other hand, the researcher was emphatic in saying that the results cannot be
can be directly extrapolated to human beings, but it will allow us to discover the
mechanisms induced by CIHH that affect cardiovascular status and
we will have clues to design pharmacological therapeutic approaches for the
people exposed to intermittent periods of low oxygen pressure, concluded
Dr. Herrera.

It is important to mention that all procedures with animals were carried out
carried out in accordance with international guidelines to safeguard the well-being of the
Laboratory animals and were approved by the Institutional Care and
Use of Animals (CICUA) of the University of Chile.

“This study was carried out on young animals and in future studies we want to
study the mechanisms that determine the observed cardiovascular failures,
In addition to investigating whether the effects are similar in individuals of medium or
old age. This is very relevant given the working age of the workers
exposed to these shifts”, reported Dr. Herrera.

Another important aspect of high altitude exposure is the maternal-fetal effects of
pregnancies in hypobaric hypoxia. Currently, Dr. Herrera is
studying the cardiovascular function of pregnant individuals in chronic hypoxia
under the Fondecyt Project 1201283.

The research also included the participation of Alejandro González-Candia, Pamela V.
Arias, Adolfo Paz and Rodrigo Castillo.

You can see the research here:
https://www.sciencedirect.com/science/article/abs/pii/S0024320523004344