Objective: Previous studies have found an association between klotho, an anti-aging hormone, and major depressive disorder. However, whether low-dose ketamine infusion alters klotho levels among patients with treatment-resistant depression (TRD) remains unknown.
Methods: In total, 48 patients with TRD and strong suicidal ideation were randomly assigned to a single 0.5 mg/kg ketamine or 0.045 mg/kg midazolam regimen and were subjected to a 2-week follow-up. Depressive and suicidal symptoms were assessed before the infusion and during the follow-up. The serum levels of klotho were assessed at baseline and 3 days postinfusion.
Results: A generalized linear model with adjustment of baseline klotho levels showed that, despite the fact that ketamine did not significantly increase levels of klotho, patients in the ketamine group had higher levels of klotho at Day 3 postinfusion than patients in the midazolam group (p = 0.043). However, we found no association between changes in klotho levels and changes in depressive and suicidal symptoms (all p > 0.05). Higher klotho levels at baseline were associated with poorer antidepressant effect of low-dose ketamine during postinfusion follow-up.
Discussion: Klotho may play a role in the antidepressant effect of low-dose ketamine. Additional molecular studies are necessary to elucidate the neuromechanisms of TRD, ketamine, and klotho.
Keywords: Ketamine; Klotho; Suicide; Treatment-resistant depression.
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