Last week, two researchers from Australia announced an exciting new discovery about gender and heart disease. We have long recognized that men generally become prone to coronary artery disease earlier than women — on average a decade earlier — perhaps supporting the notion that male sex hormones increase one’s risk of heart disease.
Although the role of androgens in cardiovascular disease remains controversial, this month scientists from Sydney’s Heart Research Institute showed the opposite: that androgens promote angiogenesis – the process whereby the body grows new blood vessels and repairs damaged ones.
Despite this new research, which appears to show that androgens or male sex hormones can protect the heart, it is not time for women (or men for that matter) to start taking testosterone to keep their hearts healthy.
Unlocking the secret to angiogenesis is paramount to the Holy Grail of cardiovascular medicine. Previously, androgens have been shown to promote growth and repair mechanisms in bone and muscle. It is not a far leap that favorable effects might also be seen in the heart.
Investigators, lead by Daniel Sieveking (right), exposed male endothelial cells (the cells that line our arteries) to a potent androgen called DHT and demonstrated a dose-dependent increase in key activities essential to blood vessel growth and repair. They also found that muscle and arteries in the leg of a mouse damaged by ischemia (lack of oxygen) – the same type of injury which occurs in strokes and heart attacks — was less severe, and recovery much faster, in those mice exposed to androgens.
The authors suggest that androgen replacement therapy might someday have a clinical role in the treatment and prevention of heart disease in men, whose levels fall as they age. Unfortunately, the administration of androgens did not favorably affect females. This is not surprising, since females have far fewer androgen receptors. (Left, an androgen receptor snuggles with testosterone.)
So do we look for ways for women to benefit from what androgens can do? Not so fast.
I think more research is needed before we start prescribing androgens for the number one killer of both men and women. We were once fairly convinced that female hormone replacement therapy was good for the heart. Now we know the reverse to be true.
Additionally, there is concern that some cancers, especially prostate cancer, will become more aggressive when exposed to higher levels of androgens. When you apply that insight to the complex mix of factors in women’s physiology, and what we learned from the Women’s Health Study, you know that no blithe suggestions can be made.
For now, this is one interesting study showing promise. It will spur further investigation. I will keep you posted on what we learn next.