Targeted Metabolomic Profiling of Carnitines Reveals Diagnostic Candidates in Postpartum Cardiomyopathy

Background: Postpartum cardiomyopathy (PPCM) is a rare but life-threatening condition characterized by left ventricular dysfunction occurring in the peripartum period. Alterations in carnitine metabolism have been implicated in myocardial energy dysregulation, yet targeted metabolic profiling in PPCM remains limited. Methods: We conducted a targeted metabolomics study comparing serum carnitine and acylcarnitine profiles between 40 PPCM patients and 40 age-matched healthy controls. Samples were analyzed using LC-MS/MS. Multivariate analyses (PCA and PLS-DA), univariate statistics (t-test, ANOVA, and Tukey's HSD), and ROC curve analysis were applied to identify discriminatory metabolites and their diagnostic potential. Results: PPCM patients showed significantly decreased free carnitine (C0, p < 0.001) and elevated short-chain acylcarnitines such as acetylcarnitine (C2, p < 0.001) and propionylcarnitine (C3, p < 0.001) compared to controls. Notably, C14:1 and C18:1 were significantly reduced, whereas C6DC was elevated in PPCM (p < 0.001). PLS-DA and VIP analyses highlighted C2, C6DC, and C16 as key discriminators between groups. ROC analysis confirmed limited but notable diagnostic performance for C2 (AUC = 0.633), C6DC (AUC = 0.635), and C16 (AUC = 0.623). Conclusions: Our findings demonstrate that PPCM is associated with profound alterations in carnitine metabolism, particularly reductions in long-chain acylcarnitines and increases in short-chain species. Specific metabolites such as C2, C6DC, and C16 may serve as potential biomarker candidates for PPCM diagnosis and prognosis. These results highlight the utility of targeted metabolomics in uncovering novel metabolic signatures of cardiomyopathy.