Drugs Stimulate Growth of New Blood Vessels By Mimicking Growth Factor
New research indicates that besides lowering levels of harmful cholesterol, the drugs may also promote the growth of new blood vessels, which may not necessarily be such a great thing. Although this effect may help to prevent heart attacks and other forms of heart disease, it may have the potential to promote cancer as well.
Tests in human cell samples and in rabbits, show that the cholesterol-lowering drug simvastatin (Zocor) seems to activate a pathway through which cells communicate and act very similar to a naturally-occurring growth factor, according to Dr. Kenneth Walsh, of Tufts University School of Medicine in Boston, Massachusetts.
Researchers suspect that the drug interacts with a molecule called protein kinase Akt/PKB, which helps regulate blood vessel development properly.
Simvastatin produced similar effects on the growth of new blood vessels, a process called angiogenesis, as does vascular endothelial growth factor (VEGF), a substance essential for healthy blood vessels, according to Dr. Walsh. "The same pathway is being activated by statins as VEGF," he said.
But if statins do promote angiogenesis, the effects may not always be helpful, Dr. Michael Simons, of Beth Israel Deaconess Medical Center in Boston points out in an editorial that accompanies the study.
For example, statins might increase the growth of blood vessels in cancerous tumors, Simons notes. However, even though statins are some of the most widely used prescription drugs, these and other potential harmful effects have not been reported, which calls into question their vessel-promoting abilities, Dr. Simons adds.
Nature Medicine September, 2000;6:965-966, 1004-1010.
Well, with half the population anticipated to take these drugs in the future, it is time that we seriously re-evaluated what we are doing with them. Just like our weight, there is an optimum with cholesterol as well. Some people believe that the lower your cholesterol, the healthier you are. Nothing could be further from the truth. If your cholesterol is too low you will have an increased risk of mood disorders, depression, stroke, violence.
This best predictor of heart disease with respect to cholesterol is the HDL/total cholesterol ratio.
Now, to add insult to injury, it appears that these drugs also contribute to increased cancer risks. Some patients (about one in 500) with impaired LDL receptors (familial hypercholesterolemia) do require these drugs and they should be on Coenzyme Q10, as this important nutrient is blocked by many cholesterol-lowering drugs. However, one in 500 people is sure a bit different than the one in 2 which is being predicted to take these drugs.
This is not the first time that the cancer-causing potential of cholesterol-lowering medications have been discussed. A review published in the prestigious Journal of the American Medical Association in 1996 (JAMA 1996 Jan 3;275:55-60) provides some excellent information on this. The authors of the study state (emphasis mine):
All members of the two most popular classes of lipid-lowering drugs (the fibrates and the statins) cause cancer in rodents, in some cases at levels of animal exposure close to those prescribed to humans. ... Longer-term clinical trials and careful postmarketing surveillance during the next several decades are needed to determine whether cholesterol-lowering drugs cause cancer in humans. In the meantime, the results of experiments in animals and humans suggest that lipid-lowering drug treatment, especially with the fibrates and statins, should be avoided except in patients at high short-term risk of coronary heart disease.
Additionally, if statins act on the same pathway as VEGF, as the study's authors state, it further explains the cancer connection. A just-published study shows that VEGF plays an important role in the spread of colorectal cancer and found that survival time was diminished in patients whose cancerous tumors tested positive for VEGF (Br J Cancer 2000 Oct;83:887-891).
Another just-published study shows that VEGF plays a role in diabetic retinopathy (Horm Res 2000;53:53-67). Therefore, if statins act along the same pathway, this is another potential adverse effect of the drugs. Considering the fact that a high percentage of diabetics have heart disease and are likely on these drugs, this is significant.