Discussion
thrombosis, TNF-α, stroke, inflammation, ischemia, endothelial cell damage, pain, TG, platelet aggregation, dyslipidemia
THROMBOSIS, TUMOR NECROSIS, INFLAMMATORY RESPONSES, STROKE, INFLAMMATION, ISCHEMIA, OXIDATIVE STRESS, DYSLIPIDEMIA
The results of this study showed that 12 weeks of curcumin-piperine supplementation reduced CIMT, hs-CRP, TC, TG, systolic and diastolic blood pressure, weight, waist circumference, and increased TAC in patients with stroke. Based on our knowledge, this study is the first clinical trial that examined the effect of curcumin-piperine on clinical as well as biochemical risk factors in patients with stroke. The findings of this study might help improve the health status of stroke patients.We observed a significant reduction in CIMT in patients with stroke supplemented with curcumin-piperine for 12 weeks. The authors were unable to find any previous trial that investigated the effects of curcumin supplementation on CIMT. However, in one study, the relationship between oxidative stress indices and antioxidant levels with CIMT in patients was explored in patients undergoing hemodialysis. In the mentioned study, a positive correlation was found between CIMT and thiobarbituric acid reactive substances (TBARS) and nitrate-to-nitrite ratio as markers of oxidative stress, while there was a negative correlation between CIMT and superoxide dismutase and catalase as antioxidants, suggesting the beneficial effects of antioxidants on the CIMT [Curcumin exerts its antioxidant effects by inhibiting superoxide radicals, hydrogen peroxide, and nitric oxide. Curcumin increases the activity of many antioxidant enzymes such as catalase, heme oxygenase, superoxide dismutase, and glutathione peroxidase, thereby preventing lipid peroxidation [This study showed a reduction in serum hs-CRP levels after 12 weeks of curcumin-piperine supplementation. The results of Gorabi et al.‘s [It has been shown that curcumin reduces inflammatory responses by reducing the activities of cyclooxygenase-2, lipoxygenase, and nitric oxide synthase enzymes, and the production of inflammatory cytokines including tumor necrosis factor-alpha (TNF-α) as well as interleukins 1, 2, 6, 8, and 12. Curcumin also inhibits nuclear factor κB (NF-κB), and NLRP3 inflammasome as key inducers of inflammation [The present study showed a decrease in systolic and diastolic blood pressure after 12 weeks of curcumin-piperine supplementation in comparison to placebo, which is in line with the results of Khajehdehi et al. [It is suggested that the effect of curcumin on lowering blood pressure is applied through the effect on antioxidant activity and vascular function of this phytochemical, which includes inhibiting reactive oxygen species (ROS), increasing the nitric oxide bioavailability, and improving the glutathione defense system [We found that curcumin-piperine intake can lower serum TC and TG concentrations. The probable mechanism of curcumin in improving dyslipidemia is reducing the activity of lipoprotein lipase [Results of a previous meta-analysis in which 26 clinical trials comprising 1890 participants were included were in line with our study [Other results from this study showed improvements in fibrinogen after 12 weeks of curcumin-piperine supplementation, although these changes were not significant compared with the placebo group. Fibrinogen is involved in platelet aggregation, endothelial cell damage, and plasma viscosity. These mechanisms play a central role in thrombosis, and thrombosis is the main cause of ischemia [Other results in this study showed that curcumin-piperine supplementation decreased weight and waist circumference compared with the control group, but BMI did not decrease significantly compared with the control group. In a meta-analysis by Akbari et al., a total of 21 clinical trials including 1604 people were included and the results showed that curcumin significantly reduced weight, BMI, and waist circumference [In the present study, curcumin-piperine supplementation was associated with a significant improvement in physical functioning, role functioning/physical, energy/fatigue, emotional well-being, and social functioning, although these changes were not significant compared with the placebo group. Moreover, curcumin caused less increase in pain compared with the control group. Curcumin’s analgesic properties have been previously reported in a meta-analysis of randomized controlled trials [This study is the first randomized, double-blind, placebo-controlled clinical trial investigating the effect of curcumin in stroke patients. Limitations of this study need to be considered. Most of the patients were > 65 years of age and the study was conducted concurrently with the Covid-19 pandemic, which made it difficult to sample and reach the appropriate sample size. In addition, we have no long-term follow-up up and due to the ethical issue, evaluation of the efficacy of curcumin-piperine alone is impossible.