The higher the levels of uric acid in the blood of amyotrophic lateral sclerosis (ALS) patients, the lower the risk of death from all causes, a study found. The body produces uric acid when it breaks down purines, which are substances both normally produced and found in certain foods and beverages.
The study also shows that, on the whole, uric acid levels are lower in the blood of ALS patients than in healthy people. Researchers suggest clinical trials testing the role of the chemical in ALS.
The study, “Serum uric acid levels in patients with amyotrophic lateral sclerosis: a meta-analysis,” was published in the journal Scientific Reports.
Oxidative stress in the central nervous system (the brain and the spinal cord) may play a role in causing damage in the central nervous system seen in ALS patients, according to some experts.
Oxidative stress is caused by forms of oxygen that are toxic to cells when present at high concentrations. The researchers point out that uric acid neutralizes these forms of oxygen, thereby reducing oxidative stress. Uric acid could potentially play a protective role in ALS, and might be used to treat it, researchers noted.
Until now, it was unclear if the chemical influences disease outcomes in ALS patients.
Researchers at the the Second Affiliated Hospital of Zhengzhou University in China pooled the results from 11 studies of uric acid levels in the blood of ALS patients.
Seven of the 11 studies were conducted with Asian patients, but three studies had Caucasians, and one study had both Asian and Caucasian patients. Overall, the studies included 4,358 ALS patients and 1,391 healthy people, used as controls.
Patients were divided into three groups, called tertiles, of lower, medium, and higher levels of the chemical, and their risk of death from all causes was assessed.
The team found that ALS patients had significantly lower levels of uric acid than healthy people.
Researchers also found that the higher the uric acid level in the blood, the lower the risk of death from all causes in people with ALS.
“Our results identified that the level of serum UA [uric acid] in ALS patients was significantly lower than that in control subjects. We also demonstrated that elevated serum UA levels were associated with lower all-cause mortality risk in patients with ALS,” the team wrote.
“In conclusion, there is an inverse association between serum UA levels and risk of death among ALS patients. UA plays a protective role in ALS. Well-designed randomized controlled trials are required to assess the therapeutic effect of UA on ALS,” the researchers concluded.