Researchers have found that the use of angiotensin-converting enzyme inhibitors, a form of hypertension medication, is associated with a reduced risk in the development of amyotrophic lateral sclerosis - also referred to as Lou Gehrig's disease.

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As ALS progresses, motor neuron cells in the body degenerate and die. This causes certain muscles to weaken and waste away.

Angiotensin-converting enzyme inhibitors (ACEIs) are widely used as medication for the treatment of hypertension and congestive heart disease.

Amyotrophic lateral sclerosis (ALS) is a prevalent form of motor neuron disease that attacks the motor neuron cells in the brainstem, spinal cord and cerebrum. This degeneration leads to muscle weakness, gradually impacting on the functioning of the body and eventually leading to death.

According to the ALS Association, around 5,600 people are diagnosed with the disease in the US every year. The organization believes that as many as 30,000 Americans could have ALS at any given time, and the average life expectancy of patients after diagnosis is between 2-5 years.

At present, ALS is treated with a drug called riluzole. It can improve the quality of life of ALS patients, but it cannot cure the disease. As a result, researchers continue to search for other forms of treatment that could be of benefit to people with this condition or reduce the risk of ALS development.

A previous study involving rats found that an ACEI called temocapril had a positive impact on the health of damaged motor neurons. The results suggested that ACEIs could protect the nerves in patients with motor neuron disease.

Until now, the effects of ACEI treatment in human cases of ALS had been unrecorded, although ACEIs have been found by researchers to be beneficial in treating other neurodegenerative diseases, such as Alzheimer's and Parkinson's disease.

A certain dosage of ACEIs associated with significant risk reduction

Dr. Feng-Cheng Lin, from the Kaohsiung Medical University Hospital in Taiwan, and colleagues conducted a case-control study of the population of Taiwan, examining what association, if any, there was between the development of ALS and the use of ACEIs.

The data analyzed were taken from the Taiwanese National Health Insurance (NHI) database, comprised of ambulatory, dental, hospital inpatient and outpatient care records.

Within the database, 729 patients had received an ALS diagnosis between January 2002 and December 2008. Their data were compared with 14,580 individuals without the disease, designated as a control group. Of the patients with ALS, around 15% reported ACEI use between 2-5 years prior to their diagnosis, compared with 18% of the control group.

The researchers measured the risk of developing ALS in both groups. They found that patients who had been prescribed ACEIs with a 449.5 cumulative define daily dose (cDDD) had their risk of ALS reduced by 17%. Patients prescribed with ACEIs greater than 449.5 cDDD faced a risk reduction of 57%.

'More animal and clinical studies required'

"The findings in this total population-based case-control study revealed that long-term exposure to ACEIs was inversely associated with the risk for developing ALS," write the researchers. "To our knowledge, the present study is the first to screen the association between ACEIs and ALS risk in a population-based study."

They suggest that ACEIs could reduce the risk of ALS by protecting motor neuron cells from the effects of overactive glutamate receptors, reducing neuroinflammation and oxidative stress, and maintaining normal levels of vitamin E within the body.

The authors of the study, published in JAMA Neurology, acknowledge that their database had certain limitations, despite its size. They note that important information regarding the time of the first symptom onset was not available, along with vitamin E intake and other important predictors of ALS, such as cigarette smoking and alcohol consumption.

These limitations mean that further research is necessary before full conclusions can be drawn. "This was an observational population-based study; hence, more animal and clinical studies are required to assess the possibility of using ACEIs for treating ALS," conclude the authors.

Another drug was recently found to have potential for treating ALS. Medical News Today reported on a study suggesting a medication normally used to treat heart failure could be adapted to treat the disease.