The Influence of Probiotic Supplementation on the Severity of Anxiety and Depressive Symptoms; Function and Composition of Gut Microbiota; and Metabolic, Inflammation, and Oxidative Stress Markers in Patients with Depression—A Study Protocol

Abstract

This article aims to present the theoretical basis, methodology, and design of a clinical trial we will conduct. The study will be prospective, randomized, placebo-controlled, and double-blind. Each intervention period will last 8 weeks and the trial will be conducted on 100 patients in total, who will be randomly divided into two groups consisting of 50 patients each. We plan to investigate the impact of Lactobacillus helveticus Rosell and Bifidobacterium longum Rosell on the depressive, anxiety, and stress levels in patients with depressive disorders with possible comorbid anxiety. In addition to assessing the influence of probiotics on the clinical condition, we also plan to study the clinical and biochemical parameters of metabolic syndrome, which often coexists with depression. Both depressive and metabolic issues may have part of their etiopathology in common, e.g., inflammation, oxidative stress, and dysbiosis. This is why we will additionally investigate the parameters related to gut microbiota, inflammatory, and oxidative statuses. Thus, the primary endpoint of the study will be the change in depression score measured with the Montgomery–Åsberg Depression Rating Scale. The secondary endpoints will include changes in anxiety and stress levels, as well as metabolic, inflammation, and oxidative stress parameters.

Exploring the Effects of Probiotic Treatment on Urinary and Serum Metabolic Profiles in Healthy Individuals

“… 79 , 80 In this perspective, one of the beneficial effects ascribed to probiotic assumption is the capability to reduce oxidative stress. 44 , 81 − 83 Accordingly, the administration of the probiotic blend tested in this study might contribute to mitigating the host’s oxidative stress as suggested by the reduction of allantoin biomarkers in urine. 84 …”

“…Urinary allantoin, an end product of purine metabolism, is normally present in urine and is formed from uric acid through reactions with oxidative species. The increase in terms of concentration of this molecule is directly associated with a systemic increase in oxidative stress. , In this perspective, one of the beneficial effects ascribed to probiotic assumption is the capability to reduce oxidative stress. ,− Accordingly, the administration of the probiotic blend tested in this study might contribute to mitigating the host’s oxidative stress as suggested by the reduction of allantoin biomarkers in urine …”