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SFU researchers Victoria Claydon (right) and Inderjeet Sahota in the Ethiopian highlands where they were part of an international team investigating Chronic Mountain Sickness.

Physiological mystery in African highlands

June 25, 2009

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Victoria Claydon often awoke in her Ethiopian-highland base camp last March to find dozens of baboons trooping past her tent on their way to the river.

The precocious primates were one of many highlights during the biomedical physiology and kinesiology assistant professor’s research field trip to study Ethiopian highlanders’ physiological adaptations to high-altitude living.

As a Heart and Stroke Foundation of Canada New Investigator with expertise in cardiovascular control, some of Claydon’s research involves studying Chronic Mountain Sickness (CMS). The debilitating disease affects about 30 per cent of Peruvians and Tibetans living around 3,000 metres above sea level but not Ethiopians living at the same altitude.

Claydon and graduate student Inderjeet Sahota were part of an international team completing a series of cardiovascular, respiratory and blood analyses on Ethiopians living at 4,000 metres.

They knew Ethiopians at slightly lower altitudes had almost normal red blood cell ratios—48 per cent compared to the normal 40 per cent—while Peruvians living at 4,000 metres have as much as 70 per cent red blood cells.

This ‘overcompensation’ or polycythaemia and extreme elevation in the percentages of red blood cells implies impaired cardiovascular control," says Claydon, "leading to the problems of CMS: dizziness, headaches, fatigue, mental confusion and a shortened life span."

The researchers determined that Ethiopians at 4,000 metres had the same moderate red-cell increase as their counterparts at slightly lower altitudes and not the extreme polycytheamia of some higher-altitude Andean populations.

And like other highlander Ethiopians, they also have higher plasma volumes than their Peruvian and Tibetan counterparts. This, says Claydon, serves to dilute the blood cells so that the percentages are normalized.

Another discovery: Ethiopians control the flow of blood and oxygen to their brain differently than their counterparts in Tibet and Peru.

Why the differences? No one knows. Claydon would like to discover the answer in hopes of determining what causes CMS.

"If we find something that’s a beneficial adaptation," she says, "maybe we can exploit that for clinical use." Such an adaptation might also benefit lowland dwellers who suffer from lower blood oxygen levels due to heart or lung disease.

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asads

oh my GOD!!! i found an article about my country,i was applying for your school. please as you are there to find something good for your people do something good for ethiopia too.i didn't mean you did bad.i said these because everyone who went there do nothing for ethiopia,they came back and talk about her poor part only.thank you and please do any good thing you can do to my country.

Inderjeet Sahota

Ever since I came back from Ethiopia all I've been doing is talking about how great the country is. I think the country is grossly misrepresented thanks to years of charity and poverty advertisements representing it as a drought-stricken and severely underdeveloped country. Ethiopia is a great place and I'd recommend anyone go visit it to see this for themselves.

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