Although the exact mechanism by which HAPE develops is unclear, "We postulate that the production of nitric oxide in the blood vessels of the lungs may be impaired in HAPE as a result of the polymorphisms in the eNOS gene. Further studies are necessary to clarify this proposition," Hanaoka says.
Confirming the genetic link could also lead to new treatments and perhaps prevention, Hanaoka says.
"It is not a dream to think about transferring the healthy eNOS gene to the human lung to compensate for the insufficient production of nitric oxide," he says.
Abnormal constriction of vessels in the lungs appears to contribute to HAPE, and studies have shown that HAPE patients have reduced nitric oxide in their lungs.
"We did this study to try to decipher the genetic cause of the nitric oxide deficit in patients with HAPE," Hanaoka says.
Researchers drew blood from 41 healthy climbers with a history of HAPE and a control group of 51 healthy climbers from the Mountaineering Association of Nagano and the Alpine Club of Shinshu University who had no history of HAPE. The HAPE group was healthy and athletic at low altitudes but suffered HAPE that required hospitalization at least once while mountain climbing. The control group, on average, had made more than 100 climbs at elevations exceeding 2,800 meters (9,186 feet) above sea level without experiencing HAPE.
All participants were Japanese, unrelated to one another, and were born and lived at elevations of less than 610 meters (2001 feet).
Using the blood samples, researchers determined the DNA sequence of the eNOS gene in each participant. They found significant differences between the HAPE patients and the control group in two variations designated Glu298Asp and 27-bp VNTR that occur in the gene.
Only 9.8 percent of the control group ca
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Contact: Maggie Francis
maggie.francis@heart.org
214-706-1397
American Heart Association
22-Jul-2002