Dietary Intake of Ascorbic Acid Attenuates Lipopolysaccharide-Induced Sepsis and Septic Inflammation in ODS Rats

Intravenous high-dose vitamin C monotherapy for sepsis and septic shock: A meta-analysis of randomized controlled trials

BACKGROUND

Vitamin C has been used as an adjuvant in the treatment of sepsis and septic shock; however, its role remains controversial. This study aimed to assess the effectiveness of intravenous high-dose vitamin C in sepsis and septic shock patients by meta-analysis.

METHODS

The PubMed, Embase, and Cochrane Library electronic databases were searched to identify relevant studies. The primary outcome was defined as the short-term all-cause mortality rate. Secondary outcomes included duration of vasoactive drug use, intensive care unit length of stay, sequential organ failure assessment scores up to 96 hours after treatment and 90-day mortality. Review Manager version 5.4 was used to perform the meta-analysis. Relative risk and mean differences (MD) with 95% confidence intervals were determined using fixed- or random-effects models.

RESULTS

Eight randomized controlled trials (RCTs) comprising 1394 patients were eligible for assessment. Overall, the pooled results showed that high-dose vitamin C decreased short-term all-cause mortality in patients with sepsis, but no significant differences were observed in patients with septic shock. Additionally, high-dose vitamin C was associated with decreased duration of vasoactive drug use in patients with sepsis, but not in patients with septic shock. However, it did not significantly affect the duration of intensive care unit stay in RCTs of patients with sepsis and septic shock. Additionally, it did not significantly affect sequential organ failure assessment scores 96 hours post-treatment or 90-day mortality.

CONCLUSION

These results suggest that intravenous high-dose vitamin C may improve outcomes in patients with sepsis, but do not benefit patients with septic shock. Further RCTs and other studies should be conducted to determine whether vitamin C should be recommended as an adjunctive sepsis treatment.

Effect of Dietary Supplements with ω-3 Fatty Acids, Ascorbic Acid, and Polyphenolic Antioxidant Flavonoid on Gene Expression, Organ Failure, and Mortality in Endotoxemia-Induced Septic Rats

Sepsis syndrome develops through enhanced secretion of pro-inflammatory cytokines and the generation of reactive oxygen species (ROS). Sepsis syndrome is characterized by vascular hyperpermeability, hypotension, multiple organ dysfunction syndrome (MODS), and increased mortality, among others. Endotoxemia-derived sepsis is an important cause of sepsis syndrome. During endotoxemia, circulating endotoxin interacts with endothelial cells (ECs), inducing detrimental effects on endothelium function. The endotoxin induces the conversion of ECs into fibroblasts, which are characterized by a massive change in the endothelial gene-expression pattern. This downregulates the endothelial markers and upregulates fibrotic proteins, mesenchymal transcription factors, and extracellular matrix proteins, producing endothelial fibrosis. Sepsis progression is modulated by the consumption of specific nutrients, including ω-3 fatty acids, ascorbic acid, and polyphenolic antioxidant flavonoids. However, the underlying mechanism is poorly described. The notion that gene expression is modulated during inflammatory conditions by nutrient consumption has been reported. However, it is not known whether nutrient consumption modulates the fibrotic endothelial gene-expression pattern during sepsis as a mechanism to decrease vascular hyperpermeability, hypotension, MODS, and mortality. Therefore, the aim of this study was to investigate the impact of the consumption of dietary ω-3 fatty acids, ascorbic acid, and polyphenolic antioxidant flavonoid supplements on the modulation of fibrotic endothelial gene-expression patterns during sepsis and to determine the effects on sepsis outcomes. Our results indicate that the consumption of supplements based on ω-3 fatty acids and polyphenolic antioxidant flavonoids was effective for improving endotoxemia outcomes through prophylactic ingestion and therapeutic usage. Thus, our findings indicated that specific nutrient consumption improves sepsis outcomes and should be considered in treatment.

Ascorbic acid attenuates activation and cytokine production in sepsis-like monocytes

Sepsis manifests due to the host's dysregulated immune response to infection. High-dose ascorbic acid (AA) has emerged as a potential treatment of sepsis, yet little is known regarding how AA influences the immune system in sepsis, such as monocytes. The objective of this study is to investigate the effects of high-dose AA on monocyte polarization and cytokine production in vitro. Monocytes isolated from healthy donors (n = 6) were polarized in vitro for 48 h using LPS or lipoteichoic acid (LTA). Polarization was confirmed by surface marker expression using flow cytometry. In parallel, monocytes from septic patients (n = 3) were analyzed for polarization markers as a comparison with the in vitro polarization. The effect of AA on monocyte polarization was then evaluated. Finally, monocytes were analyzed for cytokine production by intracellular staining. Both LPS and LTA induced polarization in healthy monocytes in vitro, with increased expression of both pro (M1) (CD40 and PDL1, p < 0.05) and anti-inflammatory (M2) (CD16 and CD163, p < 0.05) polarization markers. This pattern resembled that of monocytes from septic patients. Treatment with AA significantly inhibited surface expression of CD16 and CD163 (p < 0.05) in a dose-dependent manner. Finally, AA attenuated LPS- or LTA-induced cytokine production of IL-1ß, IL-6, IL-8, and TNF. In conclusion, AA attenuates proinflammatory cytokine production and diminishes up-regulation of CD16 and CD163, but not of CD40 and PDL-1 in LPS- or LTA-polarized monocytes. This study provides important insight into the effects of high-dose AA on monocytes and potential implications in sepsis.

Mortality in septic patients treated with vitamin C: a systematic meta-analysis

Background

Supplementation of vitamin C in septic patients remains controversial despite eight large clinical trials published only in 2020. We aimed to evaluate the evidence on potential effects of vitamin C treatment on mortality in adult septic patients.

Methods

Data search included PubMed, Web of Science, and the Cochrane Library. A meta-analysis of eligible peer-reviewed studies was performed in accordance with the PRISMA statement. Only studies with valid classifications of sepsis and intravenous vitamin C treatment (alone or combined with hydrocortisone/thiamine) were included.

Results

A total of 17 studies including 3133 patients fulfilled the predefined criteria and were analyzed. Pooled analysis indicated no mortality reduction in patients treated with vitamin C when compared to reference (risk difference − 0.05 [95% CI − 0.11 to − 0.01]; p = 0.08; p for Cochran Q = 0.002; I² = 56%). Notably, subgroup analyses revealed an improved survival, if vitamin C treatment was applied for 3–4 days (risk difference, − 0.10 [95% CI − 0.19 to − 0.02]; p = 0.02) when compared to patients treated for 1–2 or > 5 days. Also, timing of the pooled mortality assessment indicated a reduction concerning short-term mortality (< 30 days; risk difference, − 0.08 [95% CI − 0.15 to − 0.01]; p = 0.02; p for Cochran Q = 0.02; I² = 63%). Presence of statistical heterogeneity was noted with no sign of significant publication bias.

Conclusion

Although vitamin C administration did not reduce pooled mortality, patients may profit if vitamin C is administered over 3 to 4 days. Consequently, further research is needed to identify patient subgroups that might benefit from intravenous supplementation of vitamin C.

The Ameliorative Effects of Ascorbic Acid on Critical Illness Polyneuropathy in Rodent Sepsis Model

Although the exact pathophysiology of critical illness polyneuropathy (CIP) is still unknown, there are several hypotheses, some of which are increased inflammation and oxidative stress. We used rodent sepsis model in which we induced sepsis through cecal ligation followed by cecal puncture. We then administered ascorbic acid (AA) and evaluated outcomes. The levels of malondialdehyde (MDA), tumor necrosis factor α (TNF-α), interleukins (IL)-6 in the plasma, and heat shock protein-70 (HSP-70) levels in the sciatic nerve were measured, and also electromyography analyses were performed. While plasma MDA, TNF-α, and IL-6 levels were decreased significantly with AA treatment, sciatic nerve levels of HSP-70 were significantly elevated in the AA group. A significant increase in compound muscle action potential (CMAP) amplitude and a significant decrease in CMAP latency were detected in the AA group. We observed healing effects of AA on a rat model of CIP and these effects seem to be related to its anti-inflammatory and antioxidant properties.

Effect of Vitamin C, Hydrocortisone, and Thiamine vs Hydrocortisone Alone on Time Alive and Free of Vasopressor Support Among Patients With Septic Shock: The VITAMINS Randomized Clinical Trial

IMPORTANCE

It is unclear whether vitamin C, hydrocortisone, and thiamine are more effective than hydrocortisone alone in expediting resolution of septic shock.

OBJECTIVE

To determine whether the combination of vitamin C, hydrocortisone, and thiamine, compared with hydrocortisone alone, improves the duration of time alive and free of vasopressor administration in patients with septic shock.

DESIGN, SETTING, AND PARTICIPANTS

Multicenter, open-label, randomized clinical trial conducted in 10 intensive care units in Australia, New Zealand, and Brazil that recruited 216 patients fulfilling the Sepsis-3 definition of septic shock. The first patient was enrolled on May 8, 2018, and the last on July 9, 2019. The final date of follow-up was October 6, 2019.

INTERVENTIONS

Patients were randomized to the intervention group (n = 109), consisting of intravenous vitamin C (1.5 g every 6 hours), hydrocortisone (50 mg every 6 hours), and thiamine (200 mg every 12 hours), or to the control group (n = 107), consisting of intravenous hydrocortisone (50 mg every 6 hours) alone until shock resolution or up to 10 days.

MAIN OUTCOMES AND MEASURES

The primary trial outcome was duration of time alive and free of vasopressor administration up to day 7. Ten secondary outcomes were prespecified, including 90-day mortality.

RESULTS

Among 216 patients who were randomized, 211 provided consent and completed the primary outcome measurement (mean age, 61.7 years [SD, 15.0]; 133 men [63%]). Time alive and vasopressor free up to day 7 was 122.1 hours (interquartile range [IQR], 76.3-145.4 hours) in the intervention group and 124.6 hours (IQR, 82.1-147.0 hours) in the control group; the median of all paired differences was -0.6 hours (95% CI, -8.3 to 7.2 hours; P = .83). Of 10 prespecified secondary outcomes, 9 showed no statistically significant difference. Ninety-day mortality was 30/105 (28.6%) in the intervention group and 25/102 (24.5%) in the control group (hazard ratio, 1.18; 95% CI, 0.69-2.00). No serious adverse events were reported.

CONCLUSIONS AND RELEVANCE

In patients with septic shock, treatment with intravenous vitamin C, hydrocortisone, and thiamine, compared with intravenous hydrocortisone alone, did not significantly improve the duration of time alive and free of vasopressor administration over 7 days. The finding suggests that treatment with intravenous vitamin C, hydrocortisone, and thiamine does not lead to a more rapid resolution of septic shock compared with intravenous hydrocortisone alone.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03333278.