Metabolic Hormone and Adipokine Alterations in Major Depressive Disorder in Relation to the Acute-Phase Inflammatory Response and Early-Life Adversity

Major depressive disorder (MDD) involves dysregulated neuroimmune, metabolic, and oxidative stress (NIMETOX) pathways. Recently, it was shown that NIMETOX pathways should be evaluated in MDD patients stratified for metabolic syndrome (MetS). The current study aims to characterize the metabolic hormone and adipokine profiles of Chinese MDD patients stratified for MetS and to delineate their associations with overall severity of depression (OSOD), suicidal ideation (SI), recurrence of illness (ROI), and physiosomatic symptoms. We enrolled 125 MDD inpatients and 40 healthy controls and measured fasting serum insulin, glucose, glucagon, Glucose-dependent Insulinotropic Polypeptide (GIP), Glucagon-Like Peptide-1 (GLP-1), leptin, secretin, Plasminogen Activator Inhibitor-1 (PAI-1), resistin, ghrelin, and adiponectin, as well as the acute-phase inflammatory (API) response using albumin, transferrin (Tf), and monomeric CRP (mCRP). The results revealed a distinct metabolic hormone and adipokine signature in MDD with significantly lower insulin, glucagon, and PAI-1 levels, alongside an elevated API index (after adjusting for age, MetS, and body mass index). A composite GAP index (ghrelin, adiponectin, PAI-1) correlated negatively with OSOD, SI, ROI, physiosomatic symptoms, and adverse childhood experiences (ACEs). Integrative modeling combining the GAP index, API index, and ACEs achieved an area under the receiver operating characteristic (ROC) curve of 0.864 with an accuracy of 80% for discriminating MDD from controls. In conclusion, the findings delineated that many inpatients with severe MDD suffer from suppressed anabolic hormones and lower adipokine levels coupled with a mild, chronic inflammatory response. The deviations in this "hormonal-immune-metabolic" axis are components of the NIMETOX pathways in MDD and are not associated with MetS.