Preanalytical Pitfalls in Untargeted Plasma Nuclear Magnetic Resonance Metabolomics of Endocrine Hypertension

Area of Science:

• Endocrinology
• Metabolomics
• Biomarker Discovery

Background:

• Endocrine hypertension (EHT), encompassing primary aldosteronism (PA), pheochromocytoma and functional paraganglioma (PPGL), and Cushing's syndrome (CS), is often undiagnosed despite significant health impacts.
• Identifying specific biomarkers for EHT subtypes is crucial for early diagnosis and improved patient outcomes.

Purpose of the Study:

• To establish distinct metabolic signatures for different EHT forms using untargeted NMR metabolomics.
• To investigate and correct for confounding variables, such as sample origin and age, in multicenter metabolomics studies.
• To identify unbiased disease biomarkers for differentiating EHT from other forms of hypertension (PHT).

Main Methods:

• Plasma samples from 231 EHT patients (104 PA, 94 PPGL, 33 CS) and 106 PHT patients were analyzed using untargeted NMR metabolomics across 13 biobanks.
• Multivariate statistical analyses were employed to compare metabolic profiles and identify EHT-specific signatures.
• Three distinct approaches were utilized to investigate and adjust for potential confounding effects, including sample center of origin and age.

Main Results:

• Metabolic signatures were identified that could distinguish between PHT and EHT forms.
• However, significant overlap was observed between EHT signatures and confounding factors related to sample center of origin and sample age.
• The applied correction methods were limited by the study design, and no robust biomarkers for differentiating PHT from EHT were identified.

Conclusions:

• The complexity and robustness of confounding effects, particularly preanalytical variabilities, pose significant challenges in multicenter metabolomics studies.
• There is a critical need to establish consensus guidelines for handling preanalytical variabilities in retrospective metabolomics research.
• Further research with standardized protocols is required to identify reliable biomarkers for endocrine hypertension subtypes.