Treat hypertension…Prevent diabetes?

Your high blood pressure may put you on the road to developing type 2 diabetes. But taking ACE inhibitors or ARBs to fight that first problem may help you avoid the second.

Wouldn’t it be great if your high blood pressure (hypertension) medication could also reduce your risk for type 2 diabetes? It turns out that it just might: Some drugs taken to treat high blood pressure may in fact protect against the development of diabetes as well. Angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) are two classes of blood pressure medications being investigated.

Blood pressure hormone also affects glucose

ACE inhibitors and ARBs counteract the actions of an overactive renin-angiotensin system. The hormone renin helps regulate blood pressure and blood volume. High levels of renin and another hormone, angiotensin, cause blood vessels to constrict, thus raising blood pressure. Angiotensin may also affect the way the body processes sugar (glucose metabolism), for example by interfering with the functions of insulin and the pancreas (the organ that produces insulin).

By targeting the renin-angiotensin system, ACE inhibitors and ARBs may reduce insulin resistance and improve glucose metabolism as well as lower blood pressure. (The hormone insulin delivers glucose from the bloodstream to the cells, which need the glucose for energy. In insulin resistance, cells don’t readily accept the actions of insulin, causing a buildup of glucose in the blood.)

A two-pronged attack against heart disease

The idea that drugs used to treat high blood pressure and cardiovascular disease might also help prevent type 2 diabetes—itself a strong risk factor for cardiovascular disease—is intriguing, because high blood pressure and higher-than- normal blood sugar (glucose), the hallmark of diabetes, frequently occur together. There is a growing consensus among doctors that the early diagnosis and treatment of abnormal glucose metabolism in individuals who have hypertension may be an important strategy in reducing their risk of cardiovascular disease.

Many people with high blood pressure also have other cardiovascular risk factors that are not treated because they don’t yet require treatment, according to general medical guidelines. Often, high blood pressure is the only risk factor being managed even though there are other signs of trouble. For example, a recent Spanish study of 420 men and women with hypertension found that two thirds of the participants had abnormal glucose metabolism, resulting in above-normal blood sugar levels. And, the majority of this group had 2 or more cardiovascular risk factors that were not being controlled. Many had metabolic syndrome, a cluster of factors that raise a person’s risk for heart attack, stroke, type 2 diabetes, and premature death. A person is usually considered to have metabolic syndrome if at least 3 of the following risk factors are present:

• high blood pressure
• high blood glucose
• low levels of “good” (high-density lipoprotein, or HDL) cholesterol
• high levels of triglycerides (a type of blood fat, along with cholesterol)
• a large waist.

Thus, drugs that have a beneficial effect on more than one of these conditions are especially valuable, and may reveal more about the causes of the risk factors that make up the metabolic syndrome and their inter-relationship.

An atherosclerosis angle?

Research has shown that the ARB Micardis (telmisartan) decreases blood levels of glucose, cholesterol, and triglycerides in individuals who have diabetes or other glucose abnormalities—specifically, insulin resistance or impaired glucose tolerance. (A person with impaired glucose tolerance has blood glucose levels that are higher than normal but not high enough to qualify as diabetes.) Micardis also appears to be able to attach to the same cell receptors used by drugs that treat metabolic syndrome and diabetes. (Cell receptors are docking sites located on a cell’s surface where chemicals produced by the body or those in a given medication can bind with the cell.)

Researchers are investigating the idea that drugs that connect with these receptors can protect against atherosclerosis, the narrowing and stiffening of arteries caused by deposits of cholesterol and other harmful substances.

From The American Journal of Medicine