Tehran University Medical Journal

Depression is the psychological disorder which caused by chronic stress and extensive communication network between the gastrointestinal system via the “gut–brain-microbiota axis”. Depression can systematically activate/deactivate many genes and signaling molecules involved in the pathogenesis of the gastrointestinal disease. Whereas, most of the anti-depressant drugs suppress the depression symptoms by altering the neurotransmitters activity; studies on probiotics have shown the anti-depressant potential of them. Nutritional psychiatry is a field of psychiatry that investigates the relationship between dietary patterns and risk of mental disorders. The special type of probiotic has been identified to improve a number of diseases, such as diabetes, obesity, gastrointestinal infections, cancers, reduction of allergies and mood disorders such as depression. There is an evidence about therapeutic effects of probiotics in symptoms of depression, but because of the low number of samples, the limitation in use of different strains of bacteria and the limited laboratory equipment, it is difficult to make a definitive view about these results and need to more clinical study to determine the effective dose of probiotics in the treatment of depression. The articles related to this subject were collected from reliable database till the 2017 year, new studies and reviews articles which determine the effects of probiotics on the treatment of digestive and neurological diseases. The objective of this review is to study the current clinical research about the effects of probiotics in the treatment of symptoms of depression and discuss future directions in this field. Most of the studies demonstrated probiotics’ ability to improving mood, change behavior and improve the symptoms of stress and depression such as insomnia by increasing of serotonin and reducing of inflammation; and modulation of emotional behavior with effect on specific cytokines in brain. It has been discovered that probiotics have therapeutic effects extend beyond the gut and into the central nervous system by influence signaling pathways. In conclusion, it seems they have the potential to be used as a dietary supplement to optimize and enriched the food products and effective step in the prevention and treatment of various disorders in the nervous system instead of chemical drugs.

Background: Probiotics are living organisms that are beneficial for human health. Lactobacillus species has been considered as probiotic bacteria due to their adjustment of human immune responses and therapeutic effects in inflammatory disorders. The aim of the present study was to evaluate the effects of Lactobacillus probiotic strains on toll-like receptors (TLR2 and TLR4) expression in HT29 cell line (a human colon cancer cell line) infected with S. enteritidis.
Methods: This experimental study was done in Food Microbiology Research Center of Tehran University of Medical Sciences, Iran, from March 2016 to February 2017. In this study, two strains of Lactobacillus acidophilus PTCC 1643 and Lactobacillus casei PTCC 1608 were used. HT29 cells were cultured in RPMI medium containing fetal bovine serum and antibiotics. Then, the cells were treated with the Lactobacillus strains, after or before challenge with S. enteritidis. After total RNA extraction and cDNA synthesis, the capacity of probiotic lactobacilli to modulate TLR2 and TLR4 expression on treated and un-treated HT29 cells were assessed quantitatively using Real-time polymerase chain reaction technique with specific primers.
Results: Our findings indicated that after treatment of non-infected HT29 cells, with both the probiotics, the expression of TLR2 and TLR4 genes significantly increased. In contrast, the expression of these two genes in HT29 cells which were infected with S. Enteritidis was significantly reduced before and after treatment with each one of the probiotic bacteria. The anti-inflammatory effect of probiotic lactobacilli on S. enteritidis were confirmed in tests. This study showed that L. acidophilus and L. casei play a major role in boosting the innate immune responses, the TLR2 and TLR4 expression levels also decreased, pre and post-infection with S. enteritidis.
Conclusion: According to the results, both Lactobacillus strains have remarkable anti-inflammatory effect in pathogenicity of S. enteritidis, but L. acidophilus display greater anti-inflammatory activity than L. casei in this work. Additional in vivo and in vitro studies are required to further elucidate the mechanisms underlying this anti-inflammatory effect.

Background: Due to the chronic nature of diabetes, children with type 1 diabetes are prone to a number of long-term complications. One of the most important complications of this disease is cardiovascular involvement due to atherosclerosis, which is directly related to the control of blood lipids. The use of probiotics may be effective in the process of complications in these patients by affecting fat metabolism. The aim of this study was to evaluate the effect of oral probiotics on lipid profiles in children with type 1 diabetes.
Methods: This study was conducted at Bahrami Children's Hospital from May 2018 to May 2019. In this single-blind randomized controlled clinical trial, 52 children with type 1 diabetes (aged 2 to 16 years) were studied. We created two groups of 26 individuals. The inclusion criteria were determined as follows: Proof of T1DM by history and information of children’s medical record. Also, the Exclusion criteria were determined in this way: Patients consuming probiotics in the last 4 weeks, gastrointestinal infections in the last 2 weeks, and presence of chronic underlying intestinal diseases. The probiotic group received, in addition to insulin therapy, a daily probiotic capsule for 90 days. The control group received only routine insulin therapy. Blood samples were taken to measure lipid profiles at the beginning and end of the trial.
Results: A total of 52 patients were included. The mean age of children was 9.3±2.9 (4 to 14 years). The mean age in the probiotic and control groups was 9.6±3.5 and 9.4±3.0 respectively. The results of this study showed that HDL-C was increased in the probiotic group compared to the control group, although it was not statistically significant (P>0.05). Also, changes in total cholesterol, LDL-C, and triglyceride were not statistically significant.

Conclusion: In this study, the use of oral probiotics for 90 days in children with type 1 diabetes did not have a significant effect on blood lipid profiles compared to the control group.

Background: Most people often complain of abdominal bloating. The present study was designed and conducted with the purpose of examining the effect of sequential treatment of Metronidazole and Probiotics, and Probiotics alone in reducing the severity of symptoms of functional bloating.
Methods: The present study was a randomized clinical trial that was carried out from March 2022 until June 2023 in Isfahan and Khurshid Hospital. The studied population were suffering from flatulence and were diagnosed with functional bloating by a gastroenterologist based on Rome III criteria. Then they entered one of the two study groups in a double-blind manner. The first group was treated with Metronidazole for two weeks and then with Probiotic for two weeks. The second group was treated with Probiotic for four weeks. The severity of patients' bloating was measured by a 4-question questionnaire in five stages: before the start of the study, two weeks after, four weeks after, six weeks after, eight weeks after and 12 weeks after the start of the study.  Finally, the obtained information was entered into SPSS software version 24 Repeated measures ANOVA was used to investigate the relationship between variables.

Results: After collecting the data, 43 patients in the first group and 44 patients in the second group were examined. 72.1% of the first group were women and 27.9% were men. In group two, this ratio was 72.7% for women and 27.3% for men. In this intervention, it was seen that in the 1st group, the average severity of bloating decreased until the end of the eighth week and after the second week of drug treatment, and then increased. In the second group, the average intensity of bloating decreased until the end of the fourth week and at the same time as the end of drug treatment, and then increased. Conclusion: It was shown that in the study, the effect of this combined treatment had a greater effect in reducing the severity of functional bloating among patients with functional bloating.