Possible Use of Blood Tryptophan Metabolites as Biomarkers for Coronary Heart Disease in Sudden Unexpected Death

Abstract

Coronary heart disease (CHD) is the major cause of death in sudden unexpected death (SUD) cases. Tryptophan (TRP) and its metabolites are correlated with the CHD patient but less studies in the SUD. The aim of this study was to evaluate the relationship of TRP and its metabolites with the CHD in the SUD cases. Blood samples and heart tissues were collected from CHD subjects (n = 31) and the control group (n = 72). Levels of kynurenine (KYN), kynurenic acid (KYA), xanthurenic acid (XAN), 3-hydroxyanthranillic acid (HAA), quinolinic acid (QA), picolinic acid (PA) and 5-hydroxyindoleacetic acid (HIAA) were determined by HPLC-DAD. A severity of heart occlusion was categorized into four groups, and the relationship was measured with the TRP metabolites. The HIAA and The KYN levels significantly differed (p < 0.01) between the CHD group and the control group. Lower levels of QA/XAN, PA/KA, HAA/XAN, KYN/XAN and KYN/TRP were found in the CHD group. However, PA/HAA, PA/HIAA, PA/KYN and XAN/KA values in the CHD group were higher than the control group (p < 0.05). This study revealed that the values of PA/KA and PA/HAA provided better choices for a CHD biomarker in postmortem bodies.

Kynurenine Pathway Metabolites as Potential Clinical Biomarkers in Coronary Artery Disease

“…It is worth to mention that postmortem analysis of blood Trp metabolites as possible biomarkers for CAD might contribute to the investigation of sudden unexpected deaths ( 84 ). Several Trp metabolites were analyzed to help the differentiation between non-CAD and CAD pathologies after sudden unexpected deaths.…”

“…No significant differences have been identified in Trp, KYNA, 3-HAA, XA, QA, PA levels between groups. Authors have proposed that PA/KYNA and PA/3-HAA may be suitable markers for classifying non-CAD out of the CAD in sudden unexpected deaths ( 84 ).…”

“…In patients with suspected CAD, increased KYN/Trp ratio and KYN were predictive for significant CAD and both changes correlated with CAD severity ( 36 ). Post-mortem analysis have revealed that decreased KYN/Trp ratio, KYN, Trp, KYNA, 3-HAA, QA, 3-HAA/Trp, QA/PA, QA/Trp and increased PA, Trp/KYNA, PA/3-HAA, PA/KYN, PA/Trp, PA/KYNA correlated with severity of CAD occlusion ( 84 ). In chronic heart failure with implantable cardioverter-defibrillator KYN was found to be correlated with CAD severity ( 128 ).…”

Gender Differentiation in Tryptophan Metabolism in Postmortem Cases

“…The levels of TRP, KYN, KYNA, 3HK, 3HAA, QUIN, PIC, 5HTRP and HIAA in whole blood were measured by applied the method of Santisukwongchote et al 2 . The instrument for analysis was an Agilent LC 1260 infinity binary pump system.…”

“…The TRP and its metabolites levels in blood and urine have been used as a biomarker for diagnosis. For forensic medicine, the TRP and its metabolites correlated with coronary artery disease among sudden unexpected death 2 . Quinolinic acid (QUIN) and picolinic acid (PIC) level were changed significantly among suicide victims and non-suicide victims [3][4][5] .…”