Choi MR, et al. Psychiatry Investig. 2012 Sep;9(3):199-208. http://dx.doi.org/10.4306/pi.2012.9.3.199

Park JI, et al. Psychiatry Investig. 2016 Jan;13(1):152-156. http://dx.doi.org/10.4306/pi.2016.13.1.152

Background: Probiotics have been shown to enhance cognitive function in individuals with mild cognitive impairment (MCI), but their efficacy varies, depending on the strain and dosage. Objectives: Clinical investigations are crucial to confirm their safety, efficacy, and mechanism of action. This study was designed to assess the effective dosage, safety, and efficacy of MH-Pro, a test product containing Lacticaseibacillus rhamnosus CBT-LR5 (LR5) and skim milk (non-fat dry milk), in improving cognitive function and related physiological changes in older adults suspected of MCI over 12 weeks. Methods: In total, 20 participants (mean age: 68.9 years) were randomly assigned in a 1:1 ratio to either a low-dose group (1 × 10¹⁰ CFU LR5 with 1622 mg) or a high-dose group (1 × 10¹⁰ CFU LR5 with 4055 mg skim milk) in a double-blind, parallel-group clinical trial. Results: After 12 weeks, the low-dose group showed significant improvements in the MOCA-K subdomains, specifically in naming (p = 0.01) and delayed recall (p = 0.003). Additionally, levels of amyloid-β1 40/42 in the blood significantly decreased (p = 0.03) following supplementation in the low-dose group. The high-dose group exhibited significant improvement in orientation (p = 0.05). Moreover, overall cognitive enhancement was observed in the low-dose group (p = 0.003), while the high-dose group showed a trend toward improvement (p = 0.06). Fecal analysis revealed significant changes in bacterial composition, with an increase in Lacticaseibacillus after 12 weeks of MH-Pro consumption. Together, these findings provide foundational evidence suggesting that MH-Pro supplementation may serve as a potential intervention for enhancing cognitive function through gut–brain axis pathways in the elderly population. However, given the small sample size and the predominance of female participants, the impact of the outcome may be limited. Further large-scale studies are necessary to validate these preliminary results. Conclusions: This study provides foundational evidence to recognize the use of LR5 and skim milk to prepare a probiotic supplement that enhances cognitive function in the aging population.

Objective This study assessed the associations of the abnormal brain activation and functional connectivity (FC) during memory processing and brain volume alteration in conjunction with psychiatric symptom severity in patients with obsessive-compulsive disorder (OCD).Methods Twenty-OCD patients and 20-healthy controls (HC) underwent T1-weighted and functional imaging underlying explicit memory task.Results In memory encoding, OCD patients showed higher activities in right/left (Rt./Lt.) inferior temporal gyrus (ITG), medial prefrontal cortex (MPFC), dorsolateral prefrontal cortex (DLPFC) and anterior cingulate cortex (ACC), compared with HC. In task-based FC, caudate (Cd) was positively connected with DLPFC and ITG in OCD, while HC showed different connectivities of Cd-ACC and Rt.-Lt. ITG. In memory retrieval, only Cd was activated in OCD patients. Cd was positively connected with DLPFC and vmPFC in OCD, but negatively connected between same brain areas in HC. OCD patients showed increased gray matter (GM) volumes of cerebellum, DLPFC, orbitofrontal cortex (OFC), hippocampus, Cd and ITG, and concurrently, increased white matter volumes of DLPFC. In OCD patients, GM volumes of Cd and OFC were positively correlated with HAMA and Y-BOCS. Functional activity changes of Cd in OCD were positively correlated with Y-BOCS.Conclusion Our findings support to accessing clinical symptom and its severity linked by brain structural deformation and functional abnormality in OCD patients.

Shin-Eui Park, Yun-Hyeon Kim, Jong-Chul Yang, Gwang-Woo Jeong. Clin Psychopharmacol Neurosci 2022;20:279-91. https://doi.org/10.9758/cpn.2022.20.2.279