Table 2.
Significant metabolites/metabolite ratios of interest after controlling for sex and age (classical approach)
| Metabolite | PHT vs | Metabolite | PHT vs | Metabolite | PHT vs | Metabolite | PHT vs | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| CS | PA | PPGL | CS | PA | PPGL | CS | PA | PPGL | CS | PA | PPGL | ||||
| Acylcarnitines | Amino acids | Glycerophospholipids (cont.) | Sphingolipids | ||||||||||||
| C3:1 | x | Serine | x | PC aa C40:2 | x | SM C16:1 | x* | ||||||||
| C3-DC C4-OH | x | x | Threonine | x* | PC aa C40:6 | x | x* | SM C18:0 | x | x* | |||||
| C7-DC | x* | Biogenic amines | PC aa C42:0 | x* | SM C18:1 | x* | x* | ||||||||
| C9 | x* | x* | Spermidine* | x | x* | x* | PC aa C42:1 | x* | SM C20:2 | x* | |||||
| C12:1 | x | Glycerophospholipids | PC aa C42:2 | x | SM C24:1 | x* | |||||||||
| C14:1 | x* | lysoPC a C14:0 | x | PC aa C42:4 | x* | Metabolite ratio | |||||||||
| C14:2 | x | x* | lysoPC a C16:0 | x* | x* | PC aa C42:5 | x | Citrulline/Ornithine | x* | x* | x* | ||||
| C16 | x* | lysoPC a C16:1 | x* | PC ae C34:2 | x* | Citrulline/Arginine | x* | x* | |||||||
| C16:1 | x* | x* | lysoPC a C17:0 | x | PC ae C36:1 | x* | CPT-I ratio | x* | |||||||
| C18:1 | x* | x* | x* | lysoPC a C18:0 | x | PC ae C36:3 | x | Met-SO/Methionine | x* | ||||||
| C18:2 | x* | x* | x* | lysoPC a C18:2 | x* | PC ae C42:0 | x | x* | Ornithine/Arginine | x* | x* | x* | |||
| Amino Acids | lysoPC a C20:4 | x* | PC ae C42:1 | x | Putrescine/Ornithine | x* | x* | ||||||||
| Alanine | x* | lysoPC a C24:0 | x* | PC ae C42:2 | x | x | Spermidine/Putrescine | x* | x* | x* | |||||
| Arginine | x* | x* | PC aa C30:0 | x | PC ae C42:3 | x | Total DMA/Arginine | x* | x* | ||||||
| Aspartate | x* | x* | PC aa C32:2 | x | x* | PC ae C42:5 | x | Tyrosine/Phenylalanine | x* | x* | |||||
| Glutamate | x | x | PC aa C36:2 | x* | PC ae C44:3 | x | x* | ||||||||
| Ornithine | x* | x* | x* | PC aa C38:4 | x | PC ae C44:4 | x* | x | |||||||
| Phenylalanine | x | x | PC aa C38:6 | x* | PC ae C44:5 | x | |||||||||
| Proline | x | PC aa C40:1 | x* | PC ae C44:6 | x |
List of metabolites and metabolite ratios of interest found in at least 1 of the considered comparison subgroups (all patients, male, female, age <50 and ≥50 years) of PHT with CS, PA, and PPGL, respectively, with significant association with clinical diagnosis after considering sex and age group in the analysis. “x” indicates in which comparison group the metabolite/metabolite ratio has been identified (eg, C3:1 was identified in the comparison of PHT and CS, C9 in the comparison of PHT and CS as well as PHT and PA). Metabolites/metabolite ratios found using both approaches (classical and machine learning) are marked with an asterisk (*).
Abbreviations: a, acyl; aa, diacyl; ae, acyl-alkyl; CPT-I, carnitine palmitoyl transferase I; CS, cushing syndrome; Cx:y indicates the lipid chain composition where “x” is the number of carbons and “y” the number of double bonds. DMA, dimethylarginine; LysoPC, lysophosphatidylcholine; Met-SO, Methionine sulfoxide; PA, primary hyperaldosteronism; PC, phosphatidylcholine; PHT, primary hypertension; SM, sphingomyelin (see also Table 1 (30)); PPGL, pheochromocytoma/paraganglioma.