Quinolinic Acid
Overview
Quinolinic acid is an endogenous metabolite of the kynurenine pathway from tryptophan degradation, measured in cerebrospinal fluid (CSF), plasma, or urine as a marker of neuroinflammation and excitotoxicity. It acts as an agonist of NMDA receptors, contributing to neuronal damage in neurodegenerative and inflammatory conditions. Elevated levels indicate central nervous system inflammation, HIV-associated neurocognitive disorders, or ischemia, while low levels lack established clinical significance; it is primarily useful in research for monitoring neuroinflammatory diseases and assessing excitotoxic risk.
Clinical Use Cases
- Research biomarker for neuroinflammation in multiple sclerosis.
- Assessing HIV-related neurocognitive impairment.
- Investigating excitotoxicity in stroke or traumatic brain injury.
- Studying Huntington's disease progression.
- Evaluating kynurenine pathway activation in psychiatric disorders.
Specimen Types
- Cerebrospinal fluid (primary for CNS assessment).
- Plasma or serum.
- Urine.
Measurement Methods
- Liquid chromatography-tandem mass spectrometry (LC-MS/MS).
- High-performance liquid chromatography (HPLC) with fluorescence or electrochemical detection.
- Gas chromatography-mass spectrometry (GC-MS).
- Enzymatic assays (research use).
Test Preparation and Influencing Factors
- No specific fasting required.
- Avoid lumbar puncture delays for CSF stability.
- Influenced by inflammation, infections, or interferon-gamma induction.
- Tryptophan intake or IDO inhibitors may alter levels.
- Sample processing critical: freeze immediately at -80°C.
Synonyms
- QUIN.
- Pyridine-2,3-dicarboxylic acid.
- Quinolinic acid (neurotoxic kynurenine metabolite).