Viagra to aid sickle-cell victims

Famous worldwide as a restorative of male potency,  the drug Viagra could find a surprising new use in helping reduce the effects of a hereditary medical condition with the potential to affect millions of people of African ancestry.

One of the side-effects of sickle-cell anaemia – a genetic condition that alters the capacity of haemoglobin-carrying blood cells to transport oxygen – is priapism in male patients. This painful, prolonged erection that can cause irreversible damage to the penile tissue.  Users of Viagra are, of course, seeking a temporary manifestation of much the same condition.

Unlikely use for the blue pill

So scientists in Brazil postulated that if the use of a medicine like Viagra (sildenafil citrate) causes this condition in healthy people, perhaps it could open a research pathway toward alleviating more extreme symptoms in carriers of the sickle cell disease. The research is being carried out with support from FAPESP, the São Paulo Research Foundation.

One clue for leaders of the Thematic Project at the Campinas State University (UNICAMP) was that the blood of those suffering from this form of anaemia contains lower levels of nitric oxide, which is a vasodilator regulating penile erection. The drug Viagra acts by signalling the amount of nitric acid in the bloodstream.

Damaged platelets cut oxygen carrying capacity of blood

This led researcher Carla Penteado to author to a research study in The Journal of Sexual Medicine. “Priapism is a common complication among men with sickle cell anemia; however, the cause of the problem is still not very clear. We know that the blood of these patients contains a smaller quantity of nitric oxide, which is a vasodilatory agent and the main mediator of penile erection. What is expected, therefore, is greater difficulty in obtaining an erection,” explains Carla Penteado, co-author of the article.

According to Penteado, these results suggest that drugs capable of intervening in nitric oxide signalling, such as Viagra, can help to prevent priapism in patients with sickle cell anaemia. The difference is the dosage used for this distinct purpose. “One of the proposals is to use Viagra chronically in much smaller doses than recommended for treatment of sexual impotence,” she said.

The research could be significant because sickle cell anaemia – a condition resulting from an earlier stage of climatic and human history when populations living in sub-Saharan and tropical regions developed some protection against malaria – is endemic in Africa, responsible for three quarters of the world’s cases. In some parts of Saudi Arabia almost on fifth of the population are passive carriers of the gene, and all those wishing to marry must undergo a test.

Africa and Brazil share genetic origins – and a history of sickle cell anaemia.

Sickle cell anaemia deforms the  red blood cells or platelets. This dramatically reduces life expectation due to leg ulcers, retinal detachment, strokes, heart attacks, kidney failure and pulmonary failure. Furthermore, many patients must regularly undergo blood transfusions, further reducing the quality of life remaining to them.

There are believed to be around 50,000 sickle cell anaemia sufferers in Brazil, and the São Paulo research programme is looking into other symptoms including vascular occlusion. Part of the study  looks at new compositions of the haemoglobin-stimulating drug Hydroxyurea. Known as Lapdesf1, the drug showed good results in animal trials. The researchers are now seeking a partnership with the pharmaceutical industry to test the drug on humans.

Viagra cannot of course cure sickle cell anaemia, but it may perhaps alleviate one of the painful side-effects. One day, manufacturers Pfizer may be able to chalk up one more use for a medication originally designed to address heart disease.

You can read a full report on the Brazilian research by clicking here

 

 

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