Effect of resveratrol on C-reactive protein: An updated meta-analysis of randomized controlled trials

The effect of pomegranate juice supplementation on C-reactive protein levels: GRADE-assessed systematic review and dose-response updated meta-analysis of data from randomized controlled trials

Pomegranate juice (PJ) has a possible anti-inflammatory effect because of its polyphenol content and antioxidants. However, the anti-inflammatory effect of PJ in randomized controlled trials (RCTs) has not been consistent. A previous meta-analysis conducted in 2016 reported a nonsignificant lowering effect of PJ on C-reactive protein (CRP) levels. This systematic review and meta-analysis aim to update the pooled effect size of PJ supplementation on CRP levels in RCT studies. PubMed, Scopus, and Web of Science databases were comprehensively searched until July 2023. Eligible studies were found by screening, their relevant data was extracted, and a risk of bias assessment was performed. The pooled effect size was calculated using a random effect model as the weighted mean difference (WMD) with a 95% confidence interval. This systematic review included 11 studies with 13 effect sizes and 696 participants. Meta-analysis showed that PJ supplementation led to a significant decrease in CRP levels compared to control groups (WMD: -2.55 mg/L; 95%CI: -3.44 to -1.66; p < 0.001). Subgroup analysis demonstrated the significant reduction effect of PJ on CRP levels in studies conducted on the both sexes or only females as well as Iranian population, individuals with 40 years≤, type 2 diabetes, polycystic ovary syndrome, or trials that intervened with PJ dosage of <250 ml/day. Meta-regression and dose-response analysis reported a nonsignificant linear and nonlinear relationship between intervention characteristics (duration and dose of PJ) and CRP changes. The current meta-analysis revealed that PJ supplemantation has a beneficial effect in improving CRP levels. It is recommended to understand this effect better, and find the optimal dose and duration of PJ supplementation to reduce CRP levels in the blood, and repeat meta-analysis after related RCTs are available. For the final proof of these effects, more detailed human studies are needed.

Mechanism of hypoxia-induced damage to the mechanical property in human erythrocytes-band 3 phosphorylation and sulfhydryl oxidation of membrane proteins

Introduction: The integrity of the erythrocyte membrane cytoskeletal network controls the morphology, specific surface area, material exchange, and state of erythrocytes in the blood circulation. The antioxidant properties of resveratrol have been reported, but studies on the effect of resveratrol on the hypoxia-induced mechanical properties of erythrocytes are rare. Methods: In this study, the effects of different concentrations of resveratrol on the protection of red blood cell mor-phology and changes in intracellular redox levels were examined to select an appropriate concentration for further study. The Young's modulus and surface roughness of the red blood cells and blood viscosity were measured via atomic force microsco-py and a blood rheometer, respectively. Flow cytometry, free hemoglobin levels, and membrane lipid peroxidation levels were used to characterize cell membrane damage in the presence and absence of resveratrol after hypoxia. The effects of oxida-tive stress on the erythrocyte membrane proteins band 3 and spectrin were further investigated by immunofluorescent label-ing and Western blotting. Results and discussion: Resveratrol changed the surface roughness and Young's modulus of the erythrocyte mem-brane, reduced the rate of eryptosis in erythrocytes after hypoxia, and stabilized the intracellular redox level. Further data showed that resveratrol protected the erythrocyte membrane proteins band 3 and spectrin. Moreover, resistance to band 3 pro-tein tyrosine phosphorylation and sulfhydryl oxidation can protect the stability of the erythrocyte membrane skeleton net-work, thereby protecting erythrocyte deformability under hypoxia. The results of the present study may provide new insights into the roles of resveratrol in the prevention of hypoxia and as an antioxidant.

A new role for resveratrol: Protection of enamel against erosion

OBJECTIVE

The aim of this study was to determine the effect of different concentrations of resveratrol in protecting enamel against initial dental erosion in vitro.

METHODS

Ninety bovine enamel samples (4 × 4 mm) were divided into six groups: Phosphate buffered saline (negative control; PBS), Commercial solution (Elmex Erosion Protection™; positive control) and resveratrol at 4 different concentrations (1, 10, 100 or 400 µg/mL). Initially, the samples were incubated in saliva for the formation of the acquired pellicle (250 µL, 1 h, 37 °C, 250 rpm). Afterward, the samples were incubated in the respective treatments (250 µL, 1 min, 37 °C, 250 rpm) and then reincubated in saliva (250 µL, 1 h, 37 °C, 250 rpm). Finally, the samples were subjected to an erosive challenge by incubating in 1 % citric acid (1 mL, pH 3.5, 1 min, 25 °C, 250 rpm). The percentage surface microhardness change (% SMC) was assessed using a microhardness tester. Data were analyzed by Kruskal-Wallis and Dunn's tests (p < 0.05).

RESULTS

The treatments with Elmex™ and resveratrol (1, 10 and 100 µg/mL) significantly protected enamel compared to the negative control, without significant differences among them. However, the group treated with the highest resveratrol concentration (400 µg/mL) did not show a significant difference from the negative control.

CONCLUSIONS

Resveratrol at concentrations ranging from 1 to 100 µg/ml was effective in preventing loss of enamel surface microhardness.

CLINICAL SIGNIFICANCE

This result suggests a potential new direction for the development of dental products based on resveratrol for the prevention of dental erosion.

Anti-inflammatory effects of resveratrol in patients with cardiovascular disease: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Chronic inflammation is one of the most important factors involved in the development and progression of cardiovascular disease (CVDs). Accumulating evidence has described the effect of resveratrol, a natural polyphenolic compound, on biomarkers of inflammation among patients with CVDs; however, findings are controversial. Here we performed a systematic review and meta-analysis of randomized controlled trials to evaluate the effect of resveratrol supplements on TNF-α, IL-6, and CRP levels in CVDs patients.

METHODS

Online research was conducted in the following database: MEDLINE, EMBASE, Cochrane Library, Web of Science databases, and Scopus. This systematic review and meta-analysis were conducted to investigate the effects of resveratrol supplements on inflammatory biomarkers among patients with CVDs. The meta-analysis was performed using Comprehensive Meta-Analysis (CMA) V3 software.

RESULTS

Six RCTs met the inclusion criteria and were selected for the current meta-analysis. Our results demonstrated that resveratrol significantly decreases serum levels of CRP (MD= -0.63, 95% CI: -0.1.13, -0.12; p = 0.01), and TNF-α (MD= -0.55, 95% CI: -1.04, -0.06; p = 0.02), however, resveratrol had not significant effect on serum concentration of IL-6 (MD= -0.12, 95% CI: -0.52, 0.27; p = 0.53), in patients with CVDs.

CONCLUSION

Our results suggest that resveratrol can be used as a potential treatment in patients with CVD by reducing inflammatory conditions.

Resveratrol Targets AKT1 to Inhibit Inflammasome Activation in Cardiomyocytes Under Acute Sympathetic Stress

Resveratrol shows promizing anti-inflammatory effects in recent clinical trials, however its function in cardiovascular patients remains conflicting, suggesting there may be new mechanisms underlying its cardioprotective activity. Acute sympathetic stress induces early activation of the NLR family, pyrin domain containing 3 (NLRP3) inflammasome in cardiomyocytes as a critical step for triggering cardiac inflammation. Thus, this study explored targets of resveratrol activity involved in the inhibition of early inflammasome activation in cardiomyocytes following acute sympathetic stress. Network pharmacology was used to analyze common candidate targets in the sympathetic stress pathway, resveratrol activity, and myocardial inflammation and showed the Phosphoinositol 3—kinase (PI3K)/serine threonine protein kinase (Akt) signaling pathway and the target AKT1 may play a critical role. Molecular docking provided support for potential binding of resveratrol on AKT1. Furthermore, the effect of resveratrol on AKT1 activation was determined in cardiomyocytes. resveratrol dose-dependently inhibited AKT1 activation after activation of β-adrenoceptor. The AKT1 inhibitor A-674563 suppressed the activation of the NLRP3 inflammasome in cardiomyocytes following β-adrenoceptor activation, suggesting that AKT1 is a critical regulator molecule upstream of the NLRP3 inflammasome. Consistently, treatment with resveratrol suppressed β-adrenoceptor-mediated NLRP3 inflammasome activation in both cardiomyocytes and mouse hearts, as well as the resultant cardiac inflammation. In conclusion, resveratrol targets AKT1 to inhibit NLRP3 inflammasome activation in cardiomyocytes and cardiac inflammation following acute sympathetic stress. AKT1 is an important target of resveratrol, which should be considered as a treatment option for cardiovascular patients, especially those at risk of acute sympathetic stress.

Effect of Statins on Serum level of hs-CRP and CRP in Patients with Cardiovascular Diseases: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background. Several studies have reported that statins have anti-inflammatory effects. Nevertheless, results of clinical trials concerning the effect of statins on the levels of C-reactive protein (CRP) and high-sensitivity CRP (hs-CRP) have been inconsistent. Therefore, we performed a systematic review and meta-analysis of randomized clinical trials (RCTs) evaluating the effect of statins on CRP and hs-CRP levels in patients with cardiovascular diseases (CVDs). Methods. Literature search of the major databases was performed to find eligible RCTs assessing the effect of statins on serum levels of CRP and hs-CRP from the inception until the last week of April 2021. The effect sizes were determined for weighted mean difference (WMD) and 95% confidence intervals (CI). Results. 26 studies were identified (3010 patients and 2968 controls) for hs-CRP and 20 studies (3026 patients and 2968 controls) for CRP. Statins reduced the serum levels of hs-CRP ( $\text{WMD}=-0.97\text{mg}/\text{L}$ ; 95% CI: -1.26 to -0.68 mg/L; $P<0.001$ ) and CRP ( $\text{WMD}=-3.05\text{mg}/\text{L}$ ; 95% CI: -4.86 to -1.25 mg/L; $P<0.001$ ) in patients with CVDs. Statins decreased the serum levels of hs-CRP in patients receiving both high-intensity and moderate/low-intensity treatments with these drugs. In addition, the duration of treatment longer than 10 weeks decreased hs-CRP levels. Only high-intensity statin treatment could marginally decrease serum levels of CRP in CVDs patients. Conclusions. This meta-analysis showed the efficacy of statins to reduce the concentrations of CRP and hs-CRP in patients with different types of CVDs.