Metabolic Profiling of Impaired Cognitive Function in Patients Receiving Dialysis

Area of Science:

• Nephrology
• Neuroscience
• Metabolomics

Background:

• Uremic metabolite accumulation is a suspected cause of cognitive impairment in end-stage renal disease (ESRD).
• Executive function deficits are common in patients undergoing maintenance dialysis.

Purpose of the Study:

• To identify and validate uremic metabolites associated with impaired executive function in patients with ESRD on maintenance dialysis.
• To investigate the relationship between specific metabolites and cognitive performance using metabolic profiling.

Main Methods:

• Metabolic profiling using liquid chromatography/mass spectrometry on plasma samples from two cohorts (discovery: 141 patients, replication: 180 patients).
• Executive function assessed using Trail Making Test Part B and Digit Symbol Substitution test.
• Impaired executive function defined as scores ≥2 standard deviations below normative values.

Main Results:

• Four metabolites—4-hydroxyphenylacetate, phenylacetylglutamine, hippurate, and prolyl-hydroxyproline—were associated with impaired executive function in the discovery cohort.
• Associations remained significant after adjusting for demographic and clinical factors.
• The association between 4-hydroxyphenylacetate and impaired executive function was replicated in the second cohort.

Conclusions:

• Four metabolites linked to phenylalanine, benzoate, and glutamate metabolism may serve as biomarkers for cognitive impairment in dialysis patients.
• 4-hydroxyphenylacetate shows consistent association with executive function deficits across cohorts.
• Further research is warranted to elucidate the causal mechanisms.