The role of zinc homeostasis in major depressive disorder: heterogeneous pathological mechanisms and therapeutic implications.

BACKGROUND

Major depressive disorder (MDD) involves multifaceted pathologies including neurotransmission, neuroplasticity, inflammation, and hypothalamic-pituitary-adrenal (HPA) axis dysfunction. Growing evidence implicates zinc homeostasis imbalance in MDD, yet a systematic framework integrating it into these mechanisms is lacking.

METHODS

This narrative review synthesizes literature (2000-2024) to elucidate the multidimensional associations between zinc homeostasis and MDD pathology, focusing on zinc's roles in neurotransmitter regulation, BDNF signaling, inflammation, oxidative stress, and HPA axis activity.

RESULTS

Epidemiological studies indicate an inverse correlation between serum zinc levels and MDD. Mechanistically, zinc imbalance may disrupt neural signaling via glutamate/GABA/5-HT receptors, impair neurotrophy via BDNF, exacerbate neuroinflammation and oxidative stress, and promote HPA axis hyperactivity. Zinc supplementation shows efficacy in mild-to-moderate MDD and augments conventional antidepressants, especially in treatment-resistant cases. Novel targets like GPR39 and zinc transporters, along with brain-targeted formulations, offer promising therapeutic avenues.

CONCLUSIONS

Zinc homeostasis is critically involved in MDD's heterogeneous pathology, making it a promising target for precision treatment. However, this potential is tempered by inconsistent data and methodological limitations. Future research should prioritize: standardizing assessment methods; investigating brain region-specific zinc dynamics; developing novel targeted formulations; and exploring gene-environment interactions in zinc signaling.