Vitamin C decreases reduced glutathione in chronic haemodialysis patients: a pilot, randomised, double-blind trial

Whey Protein, Vitamins C and E Decrease Interleukin-10 in Chronic Hemodialysis Patients: A Pioneer, Randomized, Double-Blind Pilot Trial

OBJECTIVE

To evaluate the effects of supplementation with whey protein combined with vitamins C and E on inflammatory markers in hemodialysis (HD) patients.

DESIGN AND METHODS

This was a pioneer, randomized and double-blinded study. Patients were randomized into two groups and stratified by HD frequency. The supplementation group received 20 g of whey protein, 250 mg of vitamin C, and 600 IU of vitamin E; the placebo group, 20 g of rice flour, and microcrystalline cellulose capsules. The interventions were given after HD, 3 times a week, for 8 weeks. The inflammatory markers were assessed: interleukin (IL) IL-12p70, IL-10, IL-6, IL-8, and tumor necrosis factor alpha. For statistical analysis, the χ2 test, Student's t-test, Mann-Whitney test, analysis of variance for repeated two-way measurements, paired t test, and Wilcoxon test were performed. P < .05 was considered statistically significant.

RESULTS

Twenty-three patients completed the study. No significant differences were found in inflammatory markers when comparing the groups postintervention. In the intragroup was a decrease in IL-10 in the supplementation group after 8 weeks (P = .0382). IL-6 tended to decrease by 810.95% in the supplementation group and increased by 732.8% (nonsignificant) in the placebo group.

CONCLUSION

Whey protein combined with vitamins C and E significantly reduced IL-10 in the supplementation group and could be beneficial to reduce IL-6 in HD patients. Future studies are suggested with a larger sample size, different supplementation doses, and longer interventions.

Plasma levels of CD36 and glutathione as biomarkers for ruptured intracranial aneurysm

Evidence has proved that intracranial aneurysm (IA) formation and rupture might be closely related to inflammatory response and oxidative stress. Our objective was to evaluate the potential of CD36 and glutathione (GSH) as biomarkers for IA. In this study, the enzyme-linked immunosorbent assay was used to measure the plasma levels of CD36 and GSH in 30 IA patients and 30 healthy controls. Then, correlation analysis, receiver operating characteristic (ROC) curve, and logistic regression analysis were performed. The results showed that the plasma level of CD36 in IA patients was significantly higher than that in the control group (P < 0.0001), and plasma GSH was significantly lower compared with that in the control group (P < 0.0001). ROC analysis showed that CD36 and GSH had high sensitivity (90.0 and 96.6%) and specificity (96.6 and 86.6%) for IA diagnosis. The combined sensitivity and specificity achieved were 100 and 100%, respectively. The plasma levels of CD36 and GSH did not show a significant correlation with age, the Glasgow Coma Scale, Hunter-Hess score, aneurysm size, aneurysm height, aneurysm neck, and aspect ratio. The AUC of the logistic regression model based on CD36 and GSH was 0.505. Our results suggested that the combination of plasma CD36 and GSH could serve as potential biomarkers for IA rupture.

Antioxidants for adults with chronic kidney disease

BACKGROUND

Chronic kidney disease (CKD) is a significant risk factor for cardiovascular disease (CVD) and death. Increased oxidative stress in people with CKD has been implicated as a potential causative factor. Antioxidant therapy decreases oxidative stress and may consequently reduce cardiovascular morbidity and death in people with CKD. This is an update of a Cochrane review first published in 2012.

OBJECTIVES

To examine the benefits and harms of antioxidant therapy on death and cardiovascular and kidney endpoints in adults with CKD stages 3 to 5, patients undergoing dialysis, and kidney transplant recipients.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies until 15 November 2022 using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Registry Platform (ICTRP) Search Portal, and ClinicalTrials.gov.

SELECTION CRITERIA

We included all randomised controlled trials investigating the use of antioxidants, compared with placebo, usual or standard care, no treatment, or other antioxidants, for adults with CKD on cardiovascular and kidney endpoints.

DATA COLLECTION AND ANALYSIS

Titles and abstracts were screened independently by two authors who also performed data extraction using standardised forms. Results were pooled using random effects models and expressed as risk ratios (RR) or mean difference (MD) with 95% confidence intervals (CI). Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

MAIN RESULTS

We included 95 studies (10,468 randomised patients) that evaluated antioxidant therapy in adults with non-dialysis-dependent CKD (31 studies, 5342 patients), dialysis-dependent CKD (41 studies, 3444 patients) and kidney transplant recipients (21 studies, 1529 patients). Two studies enrolled dialysis and non-dialysis patients (153 patients). Twenty-one studies assessed the effects of vitamin antioxidants, and 74 assessed the effects of non-vitamin antioxidants. Overall, the quality of included studies was moderate to low or very low due to unclear or high risk of bias for randomisation, allocation concealment, blinding, and loss to follow-up. Compared with placebo, usual care, or no treatment, antioxidant therapy may have little or no effect on cardiovascular death (8 studies, 3813 patients: RR 0.94, 95% CI 0.64 to 1.40; I² = 33%; low certainty of evidence) and probably has little to no effect on death (any cause) (45 studies, 7530 patients: RR 0.95, 95% CI 0.82 to 1.11; I² = 0%; moderate certainty of evidence), CVD (16 studies, 4768 patients: RR 0.79, 95% CI 0.63 to 0.99; I² = 23%; moderate certainty of evidence), or loss of kidney transplant (graft loss) (11 studies, 1053 patients: RR 0.88, 95% CI 0.67 to 1.17; I² = 0%; moderate certainty of evidence). Compared with placebo, usual care, or no treatment, antioxidants had little to no effect on the slope of urinary albumin/creatinine ratio (change in UACR) (7 studies, 1286 patients: MD -0.04 mg/mmol, 95% CI -0.55 to 0.47; I² = 37%; very low certainty of evidence) but the evidence is very uncertain. Antioxidants probably reduced the progression to kidney failure (10 studies, 3201 patients: RR 0.65, 95% CI 0.41 to 1.02; I² = 41%; moderate certainty of evidence), may improve the slope of estimated glomerular filtration rate (change in eGFR) (28 studies, 4128 patients: MD 3.65 mL/min/1.73 m², 95% CI 2.81 to 4.50; I² = 99%; low certainty of evidence), but had uncertain effects on the slope of serum creatinine (change in SCr) (16 studies, 3180 patients: MD -13.35 µmol/L, 95% CI -23.49 to -3.23; I² = 98%; very low certainty of evidence). Possible safety concerns are an observed increase in the risk of infection (14 studies, 3697 patients: RR 1.30, 95% CI 1.14 to 1.50; I² = 3%; moderate certainty of evidence) and heart failure (6 studies, 3733 patients: RR 1.40, 95% CI 1.11 to 1.75; I² = 0; moderate certainty of evidence) among antioxidant users. Results of studies with a low risk of bias or longer follow-ups generally were comparable to the main analyses.

AUTHORS' CONCLUSIONS

We found no evidence that antioxidants reduced death or improved kidney transplant outcomes or proteinuria in patients with CKD. Antioxidants likely reduce cardiovascular events and progression to kidney failure and may improve kidney function. Possible concerns are an increased risk of infections and heart failure among antioxidant users. However, most studies were of suboptimal quality and had limited follow-up, and few included people undergoing dialysis or kidney transplant recipients. Furthermore, the large heterogeneity in interventions hampers drawing conclusions on the efficacy and safety of individual agents.

Does Vitamin Supplementation Play a Role in Chronic Kidney Disease?

Although the role of vitamins in the human body is proven, guidelines for patients with chronic kidney disease (CKD) remain unclear. This narrative review summarizes the findings of 98 studies of CKD and the effects of vitamin D, B, C, A, E, and K supplementation on patients on dialysis for CKD, with the aim of summarizing the existing guidelines. The findings are promising, showing the potential effectiveness of vitamin supplementation with, for example, vitamins B, D, or C. However, recommendations are still ambiguous, especially in the case of vitamins A and K, due to the potential toxicity associated with higher doses for patients. Continued research is needed to rigorously evaluate the effectiveness and carefully consider the potential risks of some vitamin supplementation for patients with CKD.

Evaluation of the combination effect of rutin and vitamin C supplementation on the oxidative stress and inflammation in hemodialysis patients

Background: Hemodialysis (HD) patients are at risk of malnutrition, cardiovascular complications, and all-cause mortality due to oxidative stress and inflammation. Some studies have demonstrated that rutin attenuates oxidative stress and inflammation in CKD rats, but its effects in HD patients are unknown to date.

Aim: The aim of this study was to evaluate the effect of rutin and vitamin C versus vitamin C alone on oxidative stress and inflammation in HD patients.

Methods: A prospective randomized, open-label, controlled trial enrolled on hundred and five HD patients divided into three groups as follows: patients in group 1 were given a rutin/vitamin C combination (Ruta C group as the combination trade name is known as Ruta C 60 tablets), patients in group 2 were given vitamin C (1 g) (vitamin C group), and group 3 was the control group; the study period was 16 weeks. The following were assessed at baseline and at the end of the study: serum malondialdehyde (MDA), glutathione peroxidase (GPx), high-sensitivity C-reactive protein (hs-CRP), tumor necrosis factor-α (TNF-α), lipid profile levels, and erythrocyte sedimentation rate.

Results: It was found that vitamin C significantly increased serum GPx in group 2 (p = 0.001) compared to a non-significant result in both group 1 and 3; in addition, serum MDA and TNF-α values had decreased significantly in the three groups compared to their baselines; however, a non-significant difference was seen among the studied groups at the end of the study. On the other hand, MDA levels were reduced by 50% in interventional groups compared to 28% in the control group, while the Ruta C group showed an 80% reduction in the level of TNF α compared to the 78% reduction observed in the vitamin C group, and finally, the interventional drugs showed a significant improvement in the lipid profile.

Conclusion: Vitamin C supplementation alone for 16 weeks had a potential effect on the antioxidant’s GPx activity. Moreover, it was reported that both vitamin C alone or the rutin/vitamin C combination (Ruta C) showed a protective role against lipid peroxidation, evidenced by the reduced levels of MDA. Finally, rutin had a favorable synergistic effect with vitamin C in reducing TG and TNF-α levels and increasing HDL-C level.

Assessment of the effect of perineural dexmedetomidine on oxidative stress during peritoneal dialysis catheter insertion: a randomized, controlled trial

Purpose

This study aimed to evaluate the effect of the addition of dexmedetomidine to ropivacaine on oxidative stress during transversus abdominis plane (TAP) and rectus sheath (RS) blockades for patients with end-stage renal disease (ESRD) undergoing peritoneal dialysis (PD) catheter insertion.

Methods

Sixty patients with ESRD undergoing PD catheter insertion to receive left ultrasound-guided TAP and RS blockades were randomly divided into two groups: the dexmedetomidine plus ropivacaine group (25 mL of 0.3% ropivacaine + 1 μg/kg dexmedetomidine) and the ropivacaine group (25 mL of 0.3% ropivacaine). Primary outcomes were oxidative stress marker levels during the procedure.

Results

A total of 60 patients (30 patients in each group) were evaluated. Compared with the ropivacaine group, the dexmedetomidine plus ropivacaine group had significantly lower serum malondialdehyde levels (P < 0.05) and increased glutathione peroxidase (P < 0.01) and superoxide dismutase levels at 24 h after the procedure (P < 0.01).

Conclusion

The addition of 1 μg/kg of dexmedetomidine to ropivacaine for ultrasound-guided TAP and RS blockades could inhibit oxidative stress in patients with ESRD undergoing PD catheter insertion.

Trial registration This study was registered at www.chictr.org.cn on June 7, 2021 (ChiCTR2100047050).