The recent findings showing that certain anti-hypertensive (drugs which lower hypertension) drugs may be helpful in Alzheimer’s disease, is consistent with the work of the Roskamp Institute. The Roskamp Institute has been conducting pioneering research in this area for several years and is currently conducting a clinical trial in Europe to test whether a hypertension lowering drug, Nilvadipine, is safe as a treatment for Alzheimer’s disease.
Nilvadipine is a known anti-hypertensive which has been used for many years in Japan and also commonly used in some parts of Europe for treatment of hypertension. Nilvadipine has had a good safety profile in both Europe and Japan.
In the past, much work has linked hypertension to Alzheimer’s disease. For instance it is known that hypertension is a risk factor for Alzheimer’s disease. However, pure hypertension can cause a dementia distinct from Alzheimer’s by casing strokes. Stroke related dementia has a number of names (multi-infarct dementia, vascular dementia) but the basic idea is that hypertension results in bleeding into the brain. This bleeding due to hypertension and consequent rupture of blood vessels in the brain can be avoided if medications are taken to lower hypertension. Nilvadipine is one of the drugs that can do this and therefore is useful in preventing stroke related dementia.
Interestingly, aside from the risk for stroke related dementia, there is also an increased risk for Alzheimer’s disease in those people with hypertension. No one really knows why this link exists. Researchers at the Roskamp Institute previously showed that amyloid can increase the constriction of blood vessels in Alzheimer’s disease. This link may explain why there is a reduction in blood flow in Alzheimer brains – but there are likely to be other reasons as well. For instance, Roskamp Institute researchers have also shown that amyloid can also reduce the growth of new blood vessels in the brain – a process called angiogenesis.
The Roskamp Institute researchers have instigated this clinical trial using Nilvadipine as it shows beneficial effects in a number of pre-clinical and clinical studies. For instance, in addition to its anti-hypertensive effects, Nilvadipine has been shown to improve cognition (mental functioning) in patients in the early stages of the disease. In a clinical trial in Japan, Nilvadipine is compared with another common anti-hypertensive drug – Amlodipine – which is used in the US for hypertension. Both drugs lower blood pressure but compared to Amlodipine, Nilvadipine specifically improves blood flow in the brain and cognitive abilities in these patients.
The recent studies show that not all anti-hypertensives are going to be useful in Alzheimer’s disease. The work of the Roskamp Institute is very much in agreement with this as they have shown that many hypertension lowering drugs are unlikely to be helpful in Alzheimer’s disease. In fact, some are likely to be more harmful as they raise the amount of amyloid in the laboratory experiments. We will learn much more about the potential use of hypertension lowering drugs as the Roskamp Institute brings Nilvadipine into clinical trials in the United States for testing its use as a treatment for Alzheimer’s disease.