Amino acid neurotransmitters predict death, disability after ischaemic stroke

Among patients who have had a stroke, those with increased glutamic acid, aspartic acid, and gamma-aminobutyric acid and decreased glycine in plasma are more susceptible to adverse outcomes, such as death or major disability, reveals a China study.

This finding suggests that plasma amino acid neurotransmitters may be used as potential targets for intervention to improve the prognosis of ischaemic stroke.

A team of investigators measured four plasma amino acid neurotransmitters (ie, glutamic acid, aspartic acid, gamma-aminobutyric acid, and glycine) among 3,486 patients with ischaemic stroke from 26 hospitals across China. The composite of death or major disability (modified Rankin Scale score ≥3) at 3 months after ischaemic stroke served as the primary endpoint.

The incidence of death or major disability was greater for ischaemic stroke patients in the highest quartile of glutamic acid (odds ratio [OR], 2.04, 95 percent confidence interval [CI], 1.60‒2.59; p_trend<0.001), aspartic acid (OR, 2.03, 95 percent CI, 1.59‒2.59; p_trend<0.001), and gamma-aminobutyric acid (OR, 1.35, 95 percent CI, 1.06‒1.71; p_trend=0.016), but lower for those in the highest quartile of glycine (OR, 0.54, 95 percent CI, 0.42‒0.69; p_trend<0.001) after multivariate adjustments.

Each standard-deviation increase of log-transformed glutamic acid, aspartic acid, gamma-aminobutyric acid, and glycine resulted in a 34-percent, 34-percent, and 9-percent higher risk and 23-percent lower risk of death or major disability, respectively (p<0.05 for all).

“Addition of the four plasma amino acid neurotransmitters to conventional risk factors significantly improved the risk reclassification, as evidenced by integrated discrimination improvement and net reclassification improvement (p<0.05 for all),” the investigators said.