The analysis of glutamate metabolism modulators in platelets of patients with temporal lobe epilepsy or status epilepticus.

OBJECTIVES

The accumulation of glutamate in the brain synaptosomes is called excitotoxicity which is an underlying mechanism of epilepsy. Platelets also contain a glutamate-glutamine cycle similar to the brain. Platelets release glutamate upon activation and also clear glutamate from the blood upon uptake. It was shown before that the platelet glutamate uptake is decreased in neurodegeneration. Therefore, we aimed to analyze the mRNA expression of Glutamate Transporter 1 (GLT-1), Glutamate Dehydrogenase (GDH), Glutamine Synthetase (GS) and Glutaminase, which are the modulators of glutamate metabolism, in isolated platelets from the blood of patients with temporal lobe epilepsy (TLE) or status epilepticus (SE) and healthy controls.

METHODS

We isolated total RNA from the platelets of TLE, SE patients and healthy controls and then carried out quantitative PCR to analyze the gene expression.

RESULTS

We observed that GLT-1, GS and glutaminase expressions are significantly higher and the expression of GDH is significantly lower in the platelets of patients with TLE or SE compared to healthy controls.

DISCUSSION: We concluded that in order to clear out and metabolize the excess glutamate GLT-1, GS and glutaminase increases in TLE and SE; however since GDH expression is lower in patients, we think that excess glutamate may not be directed to Krebs cycle resulting in lower ATP production in these diseases. We showed that platelet glutamate transporters may be used as peripheral markers to investigate the role of glutamate in patients with neurological diseases.