"This rat model has been great at showing us the neuroprotective properties of different drugs in the past, and the results usually correlate with results in humans," Dr. Catanzaro says.
In the study, 25 rats were fed the stroke-prone diet for 8 weeks and received either no medication, telmisartan alone, ramipril alone, or the two drugs together at either full- or half-doses.
"A main finding was that combination therapy did reduce blood pressure the best of any treatment, and it also was best at cutting damage to the rats' hearts and kidneys," Dr. Catanzaro says. "But what was really surprising to us was that any regimen involving telmisartan at doses that would normally be given to humans completely prevented stroke in this model. Most studies with other drugs have used much higher doses and have found only partial protection."
Specifically, 83 percent of rats given no medication showed signs of stroke, as did 56 percent of rats given ramipril alone. However, no strokes were noted in the telmisartan-only or the telmisartan/ramipril combo groups.
Telmisartan's ability to easily pass through the blood-brain barrier (something ramipril cannot do) is likely behind the neuroprotective effect noted in the study, the researchers say.
"Going forward, that's something that we would really like to test out in head-to-head trials pitting telmisartan against other ARBs, for example," Dr. Catanzaro said. "At the same time, we'd like to examine whether telmisartan is actually getting into the brain, or if more peripheral effects -- a lowering of blood pressure, for instance -- are behind the reduction in stroke."
In the meantime, Boehringer Ingelheim is nearing the end of a major clinical trial looking at the effectiveness of combining telmisartan with ramipril to lower patients' blood pressures and reduce their odds for heart attack
|Contact: Andrew Klein|
New York- Presbyterian Hospital/Weill Cornell Medical Center/Weill Cornell Medical College