Discussion
obesity, neuroinflammation, ’, PCOS, weight reduction, overweight or obesity, hyperandrogenism
OBESITY, DISORDERS, HYPERANDROGENISM, LEAKAGE, OXIDATIVE STRESS
This study mainly aimed to examine the effect of thylakoid supplementation combined with a low-calorie diet on the gut-brain axis by evaluating the levels of neurotrophic factors such as the brain-derived neurotrophic factor (BDNF) and S100 calcium-binding protein B (S100 B) in order to assess neuroinflammation caused by LPS secreted from gut microbiota in PCOS women with obesity. This study also aimed to investigate the oxidative stress markers such as malondialdehyde (MDA), catalase (CAT) levels and total antioxidant capacity (TAC) after 12 weeks of intervention. The consumption of low-calorie diet with 5 g/day thylakoid membranes of spinach during 12 weeks significantly increased the BDNF levels and decreased the LPS levels, suggesting a regulatory effect of this intervention on the gut-brain axis. Furthermore, the intervention carried out in this study had beneficial effects on the glycemic markers and sex hormones. However, the thylakoid membranes of spinach with a hypo-caloric diet had no significant effect on the oxidative stress markers in PCOS patients with obesity, which rejected our hypotheses.The observed reduction in the LPS levels in this trial may have been attributed to the capability of thylakoids to reduce the fat absorption and delay the digestion of fat [It has been also confirmed that the increase of inflammatory cytokines as a result of TRL-4 activation by LPS reduces the BDNF mRNA expression [According to our study results, decreased free testosterone index (FTI), FSH/LH ratio, and DHEA-S were also observed in both placebo and thylakoid groups, which may have improved hyperandrogenism and increased the number of mature oocytes. As Insenser M et al. [To our knowledge, in this regard, no previous human studies evaluated the effects of thylakoid membranes spinach supplementation combined with hypo-calorie diet on oxidative stress and biomarkers of gut-brain axis in individuals with PCOS. The following studies are those studies investigating the thylakoid effects: Montelius C et al. revealed that consuming 5 g of thylakoid per day resulted in the body weight reduction and reduced the desire for sweets and chocolate in individuals with overweight or obesity [
Intestinal permeability led to leakage of LPS intothe systemic circulation and stimulated the immune response and neuro-inflammation, which further increase the BBB permeability and deregulation in serum levels of S100B; also neuro-inflammation was able to alter the BDNF levels, which may have caused disorders in follicular growth. By interfering with LPS leakage and antioxidant properties, thylakoids may have impaired this series of disorders in PCOS patientsAbbreviations: BBB: blood-brain barrier; BDNF: brain-derived neurotrophic factor; LPS: lipopolysaccharides; NF-κB: nuclear factor kappa B; ROS: reactive oxygen species; S100B: S100 calcium-binding protein BThe strength of our study lies in the fact that its samples were selected from the multi-ethnic obstetrics and gynecology centers with clients from the suburbs in order to increase the generalizability of its results. Furthermore, the biweekly follow-ups performed by a dietitian as well as the examination of the patients’ problems during the intervention increased the patients’ cooperation.Our study faced few limitations. The main limitation of our study was its relatively small sample size; therefore, it was recommended that this study should be considered as a pilot study with encouraging results, and that further trials with larger sample sizes should be conducted to confirm or disconfirm our results. Second, the biochemical parameters were determined at a single time point in our study, whereas the repeated and longer measurements may have provided a stronger determination of the physiological mechanisms affecting the gut-brain axis. Third, the loads of fecal bacteria and microbiome characterization before, during, and after intervention were not determined in this study to investigate the composition of intestinal microflora. Fourth, only two markers of oxidative stress CAT, TAC and MDA were evaluated in our study; therefore, it was recommended that future studies should be carried out to investigate the remaining parameters (e.g., superoxide dismutase (SOD) and C-reactive protein (CRP)). It should be also noted that it was difficult to ensure the individuals’ adherence to a calorie-restricted diet for 12 weeks in this study.