Association between the Blautia/Bacteroides Ratio and Altered Body Mass Index after Bariatric Surgery

Background@#Current evidence support that the gut microbiota plays a potential role in obesity. Bariatric surgery can reduce excess weight and decrease the risk of life-threatening weight-related health problems and may also influence gut microbiota. In this study, we aimed to investigate the changes in gut microbiota before and after bariatric surgery and evaluate the association of the gut microbial shift and altered body mass index (BMI) after bariatric surgery. @*Methods@#Between January 2019 and July 2020, stools from 58 patients scheduled for bariatric surgery were collected. Six months after bariatric surgery, stools from 22 of these patients were re-collected, and the changes in gut microbiota before and after bariatric surgery were evaluated. In addition, the differences in gut microbiota between patients with severe obesity (BMI >35 kg/m2, n=42) and healthy volunteers with normal BMI (18.8 to 22.8 kg/m2, n=41) were investigated. @*Results@#The gut microbiota of patients who underwent bariatric surgery showed increased α-diversity and differed β-diversity compared with those before surgery. Interestingly, Blautia was decreased and Bacteriodes was increased at the genus level after bariatric surgery. Further, the Blautia/Bacteroides ratio showed a positive correlation with BMI. To validate these results, we compared the gut microbiota from severely obese patients with high BMI with those from healthy volunteers and demonstrated that the Blautia/Bacteroides ratio correlated positively with BMI. @*Conclusion@#In the gut microbial analysis of patients who underwent bariatric surgery, we presented that the Blautia/Bacteroides ratio had changed after bariatric surgery and showed a positive correlation with BMI.

Is stool frequency associated with the richness and community composition of gut microbiota?

BACKGROUND/AIMS: Recently, a number of studies have reported that the gut microbiota could contribute to human conditions, including obesity, inflammation, cancer development, and behavior. We hypothesized that the composition and distribution of gut microbiota are different according to stool frequency, and attempted to identify the association between gut microbiota and stool frequency. METHODS: We collected fecal samples from healthy individuals divided into 3 groups according to stool frequency: group 1, a small number of defecation (≤2 times/wk); group 2, normal defecation (1 time/day or 1 time/2 day); and group 3, a large number of defecation (≥2–3 times/day). We evaluated the composition and distribution of the gut microbiota in each group via 16S rRNA-based taxonomic profiling of the fecal samples. RESULTS: Fecal samples were collected from a total of 60 individuals (31 men and 29 women, aged 34.1±5.88 years), and each group comprised 20 individuals. The microbial richness of group 1 was significantly higher than that of group 3 and tended to decrease with increasing number of defecation (P<0.05). The biological community composition was fairly different according to the number of defecation, and Bacteroidetes to Firmicutes ratio was higher in group 1 than in the other groups. Moreover, we found specific strains at the family and genus levels in groups 1 and 3. CONCLUSIONS: Bacteroidetes to Firmicutes ratio and the abundance of Bifidobacterium were different according to the stool frequency, and specific bacteria were identified in the subjects with large and small numbers of defecation, respectively. These findings suggest that stool frequency might be associated with the richness and community composition of the gut microbiota.

Test–Retest Reliability of Attention Network Test Scores in Schizophrenia / 정신신체의학

OBJECTIVES: Although the Attention Network Test(ANT) has been widely used to assess selective attention including alerting, orienting, and conflict processing, data on its test-retest reliability are lacking for clinical population. The objective of the current study was to investigate test-retest reliability of the ANT in healthy controls and patients with schizophrenia. METHODS: Fourteen patients with schizophrenia and 23 healthy controls participated in the study. They are tested with ANT twice with 1 week interval. Test–retest reliability was analyzed with Pearson and Intra-class correlations. RESULTS: Patients with schizophrenia showed high test–retest correlations for mean reaction time, orienting effect, and conflict effect. Also, they showed moderate to high test-retest correlations for mean accuracy and moderate test-retest correlations for alerting effect and conflict error rate. On the other hand, healthy controls revealed high test–retest correlations for mean reaction time and moderate to high test-retest correlations for conflict error rate. In addition, they revealed moderate test-retest correlations for alert effect, orienting effect, and conflict effect. CONCLUSIONS: The mean reaction time, alerting effect, orienting effect, conflict effect, and conflict error rate of ANT showed acceptable test–retest reliabilities in healthy controls as well as patient with schizophrenia. Therefore, the analyses of these reliable measures of ANT are recommended for case-control studies in patients with schizophrenia.

The Effect of Bilateral Eye Movements on Face Recognition in Patients with Schizophrenia / 정신신체의학

OBJECTIVES: The deficit of recognition memory has been found as one of the common neurocognitive impairments in patients with schizophrenia. In addition, they were reported to fail to enhance the memory about emotional stimuli. Previous studies have shown that bilateral eye movements enhance the memory retrieval. Therefore, this study was conducted in order to investigate the memory enhancement of bilaterally alternating eye movements in schizophrenic patients. METHODS: Twenty one patients with schizophrenia participated in this study. The participants learned faces (angry or neutral faces), and then performed a recognition memory task in relation to the faces after bilateral eye movements and central fixation. Recognition accuracy, response bias, and mean response time to hits were compared and analysed. Two-way repeated measure analysis of variance was performed for statistical analysis. RESULTS: There was a significant effect of bilateral eye movements condition in mean response time(F=5.812, p<0.05) and response bias(F=10.366, p<0.01). Statistically significant interaction effects were not observed between eye movement condition and face emotion type. CONCLUSIONS: Irrespective of the emotional difference of facial stimuli, recognition memory processing was more enhanced after bilateral eye movements in patients with schizophrenia. Further study will be needed to investigate the underlying neural mechanism of bilateral eye movements-induced memory enhancement in patients with schizophrenia.

The Effect of Bilateral Eye Movements on Emotional Face Recognition Memory Task / 신경정신의학

OBJECTIVES: Previous studies have shown that bilateral eye movements enhance episodic memory retrieval. However, few studies on the effect of bilateral eye movements on emotional memory have been reported. Therefore, this study was conducted in order to investigate the differences in memory retrieval between neutral and angry stimuli after bilaterally alternating eye movements. METHODS: Twenty seven healthy right-handed subjects participated in this study. The participants learned faces (angry or neutral face), and then performed a recognition memory task in relation to the faces after bilateral eye movements and central fixation. Recognition accuracy, response bias, and mean response time to hits were compared and analyzed. Two-way repeated measure analysis of variance was performed for statistical analysis. RESULTS: There was a significant effect of bilateral eye movement conditions in recognition accuracy (F=13.833, p<0.01). Statistically significant interaction effects were observed between eye movement condition and face emotion type (F=6.253, p=0.02). CONCLUSION: In this study, recognition memory for angry faces was more enhanced than that for neutral faces after bilateral eye movements. This finding suggests that bilateral eye movements can improve recognition memory for emotional stimuli more than that for neutral stimuli.

The Effect of Bilateral Eye Movements on Emotional Face Recognition Memory Task / 신경정신의학

OBJECTIVES: Previous studies have shown that bilateral eye movements enhance episodic memory retrieval. However, few studies on the effect of bilateral eye movements on emotional memory have been reported. Therefore, this study was conducted in order to investigate the differences in memory retrieval between neutral and angry stimuli after bilaterally alternating eye movements. METHODS: Twenty seven healthy right-handed subjects participated in this study. The participants learned faces (angry or neutral face), and then performed a recognition memory task in relation to the faces after bilateral eye movements and central fixation. Recognition accuracy, response bias, and mean response time to hits were compared and analyzed. Two-way repeated measure analysis of variance was performed for statistical analysis. RESULTS: There was a significant effect of bilateral eye movement conditions in recognition accuracy (F=13.833, p<0.01). Statistically significant interaction effects were observed between eye movement condition and face emotion type (F=6.253, p=0.02). CONCLUSION: In this study, recognition memory for angry faces was more enhanced than that for neutral faces after bilateral eye movements. This finding suggests that bilateral eye movements can improve recognition memory for emotional stimuli more than that for neutral stimuli.

The Effect of Bilaterally Alternating Auditory Stimulations on the Episodic Memory Retrieval / 신경정신의학

OBJECTIVES: Previous research has shown that bilaterally alternating eye movements enhance episodic memory retrieval. This effect has been considered an important mechanism of the therapeutic effects of eye movement desensitization and reprocessing (EMDR) treatment. We conducted this study in order to test the hypothesis that bilaterally alternating auditory stimuli would also have similar effects on episodic memory retrieval. METHODS: Thirty eight right-handed subjects participated in this study. Subjects learned words, and then received bilaterally alternating auditory stimuli (as experimental stimuli) or unilateral auditory stimuli (as control stimuli). Subsequently, they performed recognition memory task. Recognition accuracy, response bias, and mean response to hits were used for evaluation of episodic memory retrieval. Repeated measures analysis of variance was performed for statistical analysis. RESULTS: There was no significant effect of experimental conditions in recognition accuracy, the response bias, and mean response time to hits. CONCLUSION: Unlike the previous positive results of bilaterally alternating eye movements, we did not observe an enhancing effect of bilaterally alternating auditory stimuli compared to unilateral auditory stimuli on episodic memory retrieval. This result suggests the possibility that the therapeutic mechanisms of EMDR might differ according to modalities of bilateral stimulation.