Source: American Physiological Society (APS)

Released: Wed 15-Jul-2009, 11:25 ET  Embargo expired: Thu 16-Jul-2009, 09:00 ET  Printer-friendly Version

One Disease, Two Effects: Stroke

Newswise — Congress is expected to take up legislation this summer aimed at improving the nation’s healthcare system. Whatever the shape of the final bill, it will have at least some impact on one of the three leading causes of death in the U.S.: stroke.

Stroke typically occurs when arteries become blocked, preventing blood from flowing to the brain. When the brain is deprived of blood and oxygen, brain cells die and long-term brain damage results. For this reason, a stroke is also known as a brain attack. It is an illness that affects male and female brains differently although scientists are not sure why.

To discuss the current state of gender research and stroke, Patricia Hurn, a renowned expert in stroke and sex differences, and Professor and Vice Chair for research in the Department of Anesthesiology and Perioperative Medicine at Oregon Health and Science University (OHSU) School of Medicine, will address attendees at the Sex Steroids and Gender in Cardiovascular-Renal Physiology and Pathophysiology conference, being held July 15-18, 2009 in Broomfield, Colorado. The program, sponsored by The American Physiological Society (www.the-aps.org/press), attracts scientists in the field of gender biology, physiology, medicine and related fields.

Stroke and Gender
While both males and females are at risk for stroke, males have a particular sensitivity. Data show that male stroke victims outnumber females by about two to one. Actor Kirk Douglas, Cuban leader Fidel Castro and singer Barry White are among high profile men who have suffered a stroke.

Women are likewise at risk for stroke and, as they age, their outcomes are often worse than their male counterpart’s. Hurn thinks the outcomes phenomenon may be because women are typically older than men when a stroke occurs.

In terms of stroke treatment, men again have a disadvantage. For example, tissue plasminogen activator (tPA), the only drug therapy approved by the FDA for stroke treatment, has been shown to improve stroke outcome and generate brain damage response in women but to a lesser extent in men. And even at the smallest level of new discovery -- the molecular and cellular level -- male and female dish cultures respond differently.

Is Estrogen the Answer to Stroke Prevention?
Since females carry the sex hormone estrogen researchers have long examined whether it protects the XY brain and thus shields it from stroke’s injury and damage. Large scale and in-depth studies of animals have shown that there is a protective effect for animals, but results in human studies have been less conclusive.

In fact, in the U.S. government’s largest study involving estrogen and cardiovascular disease, known as the Women’s Health Initiative (WHI), researchers found a small detrimental risk of stroke among the women taking estrogen. Whether the risk was an anomaly due to the study parameters is not yet clear. In the meantime the effect of estrogen remains an unexplained variable in the effort to understand stroke.

A New Focus: Testosterone
Researchers have focused on the effect of estrogen for more than 15 years. With no apparent conclusion at hand, Hurn and her colleagues have shifted their investigative focus to the influence of testosterone, the primary male hormone, in stroke. According to Hurn, “We think this approach, coupled with examining brain stroke injury at the molecular and cellular level, is the best way to get at some of the underlying issues that have challenged us scientists for so long.”

Conclusion
Despite the fact that men are more likely to suffer a stroke, they are not the only ones affected. The differences between male and female stroke may in fact put women at a greater disadvantages than men in terms of their health outcomes. “It is our hope that by bringing fresh approaches to existing studies we may be able to improve the chances of surviving a disease that strikes one individual every 45 seconds, and kills an individual every three minutes,” says Hurn.

Physiology is the study of how molecules, cells, tissues and organs function to create health or disease. The American Physiological Society (APS; http://www.the-APS.org/press) has been an integral part of the discovery process since it was established in 1887.

To review the complete program for the Sex Steroids and Gender conference, log on to http://www.the-aps.org/meetings/aps/gender/index.htm for a copy of the complete program.