Effects of alpha-lipoic acid supplementation on C-reactive protein level: A systematic review and meta-analysis of randomized controlled clinical trials

BACKGROUND AND AIM

The aim of this meta-analysis was to assess effects of alpha-lipoic acid supplementation on C-reactive protein (CRP) levels in clinical trial studies.

METHODS AND RESULTS

A systematic search was carried out on clinical trial studies published in PubMed, ISI Web of Science, Cochrane Library and Scopus databases completed by manual search on reference list of eligible studies accomplished by November 4, 2017. Of a total number of 508 studies found in the first step of literature search, only 11 were included with 264 participants in supplementation groups and 287 in control groups. Estimated pooled random effects size analysis showed a significant reducing effect of alpha-lipoic acid supplementation on CRP level (-0.72 mg/l, 95% CI; -1.4, -0.04; P = 0.03) with a significant heterogeneity between the selected studies. Sub-group analysis showed that alpha-lipoic acid supplementation could significantly reduce serum CRP level when the baseline CRP level was greater than 3 mg/l (-1.02 mg/l, 95% CI: -1.3, -0.73) and when trial duration was >8 weeks (-0.99 mg/l, 95% CI: -1.29, -0.70). Results of subgroup analysis also showed that alpha lipoic acid supplementation could decrease CRP level only in non-diabetic patients (-1.02 mg/l, 95% CI: -1.31, -0.74).

CONCLUSIONS

Results of the current meta-analysis study showed that alpha-lipoic acid supplementation could significantly decrease CRP level in patients with elevated levels of this inflammatory marker.

Beneficial effects of omega-3 and vitamin E coadministration on gene expression of SIRT1 and PGC1α and serum antioxidant enzymes in patients with coronary artery disease

BACKGROUND AND AIM

SIRT1 and PGC1α are two important genes, which play critical roles in regulating oxidative stress and inflammation processes. The study aimed assess the effects of coadministration of omega-3 and vitamin E supplements on SIRT1 and PGC1α gene expression and serum levels of antioxidant enzymes in coronary artery disease (CAD) patients.

METHODS AND RESULTS

Participants of this randomized controlled trial included 60 CAD male patients who were categorized into three groups: Group 1 received omega-3 (4 g/day) and vitamin E placebo (OP), group 2 omega-3 (4 g/day) and vitamin E (400 IU/day; OE), and group 3 omega-3 and vitamin E placebos (PP) for 2 months. Gene expression of SIRT1 and PGC1α in peripheral blood mononuclear cells (PBMCS) was assessed by reverse transcription polymerase chain reaction (RT-PCR). Furthermore, serum antioxidant enzyme and high-sensitivity C-reactive protein (hsCRP) levels were assessed at the beginning and end of the intervention. Gene expression of SIRT1 and PGC1α increased significantly in the OE group (P = 0.039 and P = 0.050, respectively). Catalase and hsCRP levels increased significantly in the OE and OP groups. However, glutathione peroxidase (GPX) and superoxide dismutase (SOD) levels did not statistically change in all groups. The total antioxidant capacity (TAC) increased significantly in the OE group (P = 0.009) but not in OP and PP groups.

CONCLUSION

Supplementation of omega-3 fatty acids in combination with vitamin E may have beneficial effects on CAD patients by increasing gene expression of SIRT1 and PGC1α and improving oxidative stress and inflammation in these patients.

The comparison of serum vaspin and visfatin concentrations in obese and normal weight women

BACKGROUND AND OBJECTIVES

There is evidence based studies which show that plasma level of visfatin and vaspin in patients with type 2 diabetes mellitus elevate in comparison with healthy people. But there is no consistency in plasma visfatin and vaspin concentration between studies done on obese people. For this reason, the aim of this study is to investigate the serum level concentrations of visfatin and vaspin in obese women compared to normal weight women.

MATERIALS AND METHODS

The participants of this study consist of 43 women aged 20-50, and 43 healthy women with normal weight as a control group. They were matched for age and physical activity. 24h food recall was used to collect dietary information from subjects. Moreover, blood sampling was taken to measure the blood levels of sugar, lipid profile, vaspin and visfatin.

RESULTS

The mean serum level of visfatin was not statistically different between obese and normal weight women. But, the obese women had statistically higher mean serum level of vaspin than normal women (p=0.04). We found no relations between serum levels of vaspin with serum concentration of visfatin. Also, serum levels of these two adipokines were not related to the serum concentrations of fasting glucose, total cholesterol, low-density lipoprotein cholesterol and triglyserides and high-density lipoprotein cholesterol. Also, there was a significant positive relationship between carbohydrate intake and serum visfatin level in women participating to this study (p=0.018, r=0.257).

CONCLUSION

The results of this study demonstrated that the level of serum vaspin was significantly higher in obese women. But there were no differences in serum levels of visfatin in comparison to normal weight women. Meanwhile this study demonstrated a positive relationship between serum levels of visfatin with dietary intake of carbohydrate, but no relationship between serum level of visfatin and vaspin in women participating in this study.