Vitamin C revisited

Vitamin C for all?

PURPOSE OF REVIEW

Vitamin C can be a potential adjunctive treatment option for critically ill individuals due to its pleiotropic effects as electron donor in many enzymatic reactions throughout the body. Recently, several important randomized controlled trials (RCTs) investigating vitamin C in critically ill patients have been published.

RECENT FINDINGS

Two recent large RCTs administering high-dose vitamin C to patients with sepsis and COVID-19 showed signs of harm. Though performed at high standard, these trials had several limitations. Recent studies in cardiac surgery and burns showed decreased cardiac enzymes and improved clinical outcomes after cardiac surgery, and decreased fluid requirements, reduced wound healing time and in-hospital mortality after burns. Vitamin C may hold benefit in the management of other ischemia/reperfusion injury populations, including postcardiac arrest patients and after solid organ transplantation. Currently, covering basal vitamin C requirements during critical illness is recommended, though the exact dose remains to be determined.

SUMMARY

Future work should address optimal vitamin C timing, since early versus late drug administration are likely distinct, and duration of therapy, where withdrawal-induced injury is possible. Additionally accurate assessment of body stores with determination of individual vitamin requirements is crucial to ascertain patient and subgroups most likely to benefit from vitamin C.

Association between serum vitamin C and body mass index in adolescents aged 12-19 years

BACKGROUND

Evidence on the association between serum vitamin C (sVC) levels and obesity is limited. This study aimed to explore the relationship between sVC and body mass index (BMI) in adolescents aged 12 to 19 years.

METHODS

We analyzed data from the National Health and Nutrition Examination Survey (NHANES) 2003-2006, with 3952 participants. sVC and BMI were independent variables and dependent variables, respectively. The associations of sVC with BMI were examined using multivariable linear regression models. Age, sex, and race/ethnicity were analyzed as subgroups. Then, we devised smooth curve fittings and saturation threshold analysis to address the nonlinear relationship.

RESULTS

sVC had a negative correlation with BMI after adjusting for all covariates (β: -1.020, 95% CI: -1.359, -0.680). In the subgroup analysis by age, sex, and race/ethnicity, there was still a negative correlation between sVC and BMI (p < 0.05). The analysis of saturation effects of sVC and BMI showed the relationship between sVC and BMI in female adolescents followed an N-shaped curve, whereas the relationship between sVC and BMI in adolescents aged 12-15 years and Mexican Americans followed a U-shaped curve.

CONCLUSION

Based on the results, proper vitamin C supplementation may be beneficial to weight loss. However, considering the threshold effect, large-scale and good-quality randomized controlled trials are required to obtain the optimal vitamin C level for weight control.

Preoperative and postoperative administration of vitamin C in cardiac surgery patients - settings, dosages, duration, and clinical outcomes: a narrative review

Vitamin C or ascorbic acid is a water-soluble vitamin capable of directly donating electrons to reactive oxygen species, attenuating electrical remodeling, and cardiac dysfunction in patients undergoing cardiac surgery (CS), considered one of the most effective defenses against free radicals in the blood, thus being one of the first antioxidants consumed during oxidative stress. The aim of this review is to assess the effects of perioperative administration of vitamin C in CS patients. A comprehensive literature search was conducted in order to identify prospective cohort studies and/or randomized controlled trials reporting on the perioperative effects of vitamin C among adult patients undergoing CS. Studies published between January 1980 to December 2022 were included in our search, resulting in a total of 31 articles that met all our inclusion criteria. There seems to be a beneficial effect of vitamin C supplementation in arrhythmias such as in postoperative atrial fibrillation, reduction of ICU length of stay, and hospital length of stay, reduction in postoperative ventilation time, in inotropic demand, and in postoperative fatigue. Vitamin C can act as a scavenger of free radicals to decrease the peroxidation of the lipids present in the cell membrane, and to protect the myocardium postoperatively from ischemia/reperfusion injury, thus attenuating oxidative stress and inflammation. It represents a readily available and cost-effective strategy that could improve the outcome of patients undergoing CS, by reducing the risk of serious cardiovascular adverse events, both perioperatively and postoperatively.

Patent Mining on the Use of Antioxidant Phytochemicals in the Technological Development for the Prevention and Treatment of Periodontitis

Periodontal disease is an inflammatory condition characterized by an aberrant immune response against a dysbiotic dental biofilm, with oxidative stress performing an essential role in its pathogenesis. This paper presents a patent mining, performed in the Orbit Intelligence patent database, related to antioxidant phytochemicals in the technological developments that are working to prevent and treat periodontal disease. To access the documents, the descriptors "PERIODONTAL" and "ANTIOXIDANT" were typed in the title, abstract, and claim search fields. A total of 322 patents demonstrate the growing interest in researching natural antioxidants for scientific and technological purposes. The top ten countries regarding the number of family patents produced were the United States, the European Office, Japan, South Korea, China, India, Mexico, Denmark, Canada, and Great Britain. The most cited compounds were vitamin C, green tea, quercetin, melatonin, lycopene, resveratrol, and curcumin. These compounds have been used for the technological development of gels, membranes, dentifrices, chewing gum, orally disintegrating film, mouthwash, mouth spray, and mouth massage cream and exhibit the ability to neutralize free radicals and reduce oxidative stress, a critical factor in the development and progression of periodontal diseases. The patent documents have shown that using antioxidant compounds in conjunction with traditional periodontal treatments is a promising area of interest in periodontal therapy.

High-dose vitamin C improves norepinephrine level in patients with septic shock: A single-center, prospective, randomized controlled trial

BACKGROUND

The effects of vitamin C supplementation on patients with septic shock remain controversial. We aimed to evaluate the effects of different vitamin C dosages on norepinephrine (NE) synthesis in adult patients with septic shock.

METHODS

A total of 58 patients with septic shock admitted to our intensive care unit (ICU) between July 2021 and December 2022 were included. Patients were randomly divided into 3 groups: high-dose vitamin C (150 mg/kg/d, group A), low-dose vitamin C (50 mg/kg/d, group B), and placebo (group C). NE synthesis-related indicators (dopamine-β-hydroxylase [DβH], tyrosine hydroxylase [TH], tetrahydrobiopterin [BH4], and dopamine [DA]), plasma NE, and vitamin C levels were measured every 24 hours and analyzed. All-cause mortality within 28 days and other clinical outcomes (including Acute Physiology and Chronic Health Evaluation [APACHE], Sequential Organ Failure Assessment [SOFA], and Multiple-Organ Dysfunction Syndrome [MODS] scores) were compared.

RESULTS

Changes in TH, BH4, and DβH levels at 96 hours in groups A and B were greater than those in group C. These differences became more pronounced over the course of the intravenous vitamin C administration. Significant differences between groups A and C were detected at 96-hours TH, 72-hours BH4, 96-hours BH4, 96-hours DA, and DβH levels every 24 hours. The 96-hours TH, 96-hours BH4, and 48-hours DβH in group B were significantly higher than those in group C. The NE levels every 24 hours in groups A and B were higher than those in group C, group A and group C had a statistically significant difference. The 96-hours exogenous NE dosage in groups A and B was significantly lower than that in group C. No significant reductions in APACHE, SOFA, or MODS scores were observed in the vitamin C group, including the duration of ICU stay and mechanical ventilation. The 28-days mortality was lower in groups A and B than in group C (0%, 10%, and 16.67%, P = .187), but the difference was not significant.

CONCLUSION

For patients with septic shock, treatment with vitamin C significantly increased TH, BH4, and DβH levels and reduced the exogenous NE dosage, but did not significantly improve clinical outcomes.

ESPEN practical short micronutrient guideline

BACKGROUND

Trace elements and vitamins, named together micronutrients (MNs), are essential for human metabolism. The importance of MNs in common pathologies is recognized by recent research, with deficiencies significantly impacting the outcome.

OBJECTIVE

This short version of the guideline aims to provide practical recommendations for clinical practice.

METHODS

An extensive search of the literature was conducted in the databases Medline, PubMed, Cochrane, Google Scholar, and CINAHL for the initial guideline. The search focused on physiological data, historical evidence (for papers published before PubMed release in 1996), and observational and/or randomized trials. For each MN, the main functions, optimal analytical methods, impact of inflammation, potential toxicity, and provision during enteral or parenteral nutrition were addressed. The SOP wording was applied for strength of recommendations.

RESULTS

The limited number of interventional trials prevented meta-analysis and led to a low level of evidence for most recommendations. The recommendations underwent a consensus process, which resulted in a percentage of agreement (%): strong consensus required of >90 % of votes. Altogether the guideline proposes 3 general recommendations and specific recommendations for the 26 MNs. Monitoring and management strategies are proposed.

CONCLUSION

This short version of the MN guideline should facilitate handling of the MNs in at-risk diseases, whilst offering practical advice on MN provision and monitoring during nutritional support.

Prevalence, risk factors, and clinical outcomes of vitamin C deficiency in adult hospitalized patients in high-income countries: a scoping review

BACKGROUND

Assessment for vitamin C deficiency (VCD) is rarely undertaken in an acute hospital setting in high-income countries. However, with growing interest in VCD in community settings, there is emerging evidence investigating the prevalence and impact of VCD during hospitalization.

OBJECTIVES

In this scoping review, the prevalence of VCD in adult hospitalized patients is explored, patient characteristics are described, and risk factors and clinical outcomes associated with VCD are identified.

METHODS

A systematic scoping review was conducted in accordance with the PRISMA-ScR framework. The Ovid MEDLINE, Ovid Embase, Scopus, CINAHL Plus, Allied and Complementary Medicine Database, and the Cochrane Library databases were searched for interventional, comparative, and case-series studies that met eligibility criteria, including adult hospital inpatients in high-income countries, as defined by the Organization for Economic Co-operation and Development, that reported VCD prevalence using World Health Organization reference standards. These standards define VCD deficiency as plasma or serum vitamin C level <11.4 µmol/L, wholeblood level <17 µmol/L, or leukocytes <57 nmol/108 cells.

RESULTS

Twenty-three articles were included, representing 22 studies. The cumulative prevalence of VCD was 27.7% (n = 2494; 95% confidence interval [CI], 21.3-34.0). High prevalence of VCD was observed in patients with severe acute illness and poor nutritional status. Scurvy was present in 48% to 62% of patients with VCD assessed in 2 studies (n = 71). Being retired (P = 0.015) and using excessive amounts of alcohol and tobacco (P = 0.0003) were independent risk factors for VCD (n = 184). Age was not conclusively associated with VCD (n = 631). Two studies examined nutrition associations (n = 309); results were inconsistent. Clinical outcomes for VCD included increased risk of frailty (adjusted odds ratio, 4.3; 95%CI, 1.33-13.86; P = 0.015) and cognitive impairment (adjusted odds ratio, 2.93; 95%CI, 1.05-8.19, P = 0.031) (n = 160).

CONCLUSIONS

VCD is a nutritional challenge facing the healthcare systems of high-income countries. Research focused on early identification and treatment of patients with VCD is warranted.

SYSTEMATIC REVIEW REGISTRATION

Open Science Framework ( https://doi.org/10.17605/OSF.IO/AJGHX ).

Vitamin C deficiency in critically ill COVID-19 patients admitted to intensive care unit

Objectives

To determine vitamin C plasma kinetics, through the measurement of vitamin C plasma concentrations, in critically ill Coronavirus infectious disease 2019 (COVID-19) patients, identifying eventually the onset of vitamin C deficiency.

Design

Prospective, observational, single-center study.

Setting

Intensive Care Unit (ICU), Vall d'Hebron University Hospital, Barcelona. Study period from November 12th, 2020, to February 24th, 2021.

Patients

Patients who had a severe hypoxemic acute respiratory failure due to COVID-19 were included.

Interventions

Plasma vitamin C concentrations were measured on days 1, 5, and 10 of ICU admission. There were no vitamin C enteral nor parenteral supplementation. The supportive treatment was performed following the standard of care or acute respiratory distress syndrome (ARDS) patients.

Measurement

Plasma vitamin C concentrations were analyzed using an ultra-performance liquid chromatography (UPLC) system with a photodiode array detector (wavelength set to 245 nm). We categorized plasmatic levels of vitamin C as follows: undetectable: < 1,5 mg/L, deficiency: <2 mg/L. Low plasma concentrations: 2-5 mg/L; (normal plasma concentration: > 5 mg/L).

Main results

Forty-three patients were included (65% men; mean age 62 ± 10 years). The median Sequential Organ Failure Assessment (SOFA) score was 3 (1-4), and the Acute Physiology and Chronic Health disease Classification System (APACHE II) score was 13 (10-22). Five patients had shock. Bacterial coinfection was documented in 7 patients (16%). Initially all patients required high-flow oxygen therapy, and 23 (53%) further needed invasive mechanical ventilation during 21 (± 10) days. The worst PaO2/FIO2 registered was 93 (± 29). ICU and hospital survival were 77 and 74%, respectively. Low or undetectable levels remained constant throughout the study period in the vast majority of patients.

Conclusion

This observational study showed vitamin C plasma levels were undetectable on ICU admission in 86% of patients with acute respiratory failure due to COVID-19 pneumonia requiring respiratory support. This finding remained consistent throughout the study period.

[Effect of a multivitamin on insulin resistance, inflammation, and oxidative stress in a Wistar rat model of induced obesity]

Introduction

Introduction: excessive accumulation of adipose tissue is accompanied by alterations in the inflammatory state and increased oxidative stress, and these variables are associated with insulin resistance and increased glucose and insulin levels. On the other hand, vitamins and minerals reinforce the antioxidant and inflammatory capacity, for this reasons we propose that they could contribute to the control of insulin resistance, glucose and lipid metabolism in a rat model of obesity. Objective: to analyze the effect of a multivitamin supplement on markers of insulin resistance, inflammation, and oxidative stress in obese rats on a cafeteria diet. Methods: thirty-five 28-day-old male Wistar rats were randomly divided into four groups: 1, standard diet control; 2, standard diet plus multivitamin; 3, obese on a cafeteria diet; and 4, obese on a cafeteria diet plus multivitamin. After the treatments, glucose levels, HbA1c, insulin, TNF-α, IL-6, oxidative stress and lipid profile were analyzed by colorimetric methods, as well as the percentage of adipose tissue, Homeostasis Model Assessment (HOMA) index y Quantitative Insulin Sensitivity Check Index (QUICKI). Results: multivitamin supplementation significantly decreased visceral adipose tissue, HOMA index, glucose, HbA1c, oxidant stress, and inflammatory markers in the obese plus multivitamin rat group, compared with the obese cafeteria diet rat group and the standard diet rat control group. However, the group that was administered only the multivitamin without the cafeteria diet had increased levels of total adipose tissue, glucose, and oxidative stress, as well as the QUICKI index relative to the control group with the standard diet. Conclusion: co-administration of a multivitamin supplement may improve insulin sensitivity, glucose metabolism and lipid profile; strengthen antioxidant status; and decrease inflammation during weight gain. However, it was not expected that added sugars in multivitamin supplement can also increase total adipose tissue, oxidative stress and glucose levels, so it is suggested to use sugar-free multivitamins in the future.

In vitro and in vivo efficacy of a cosmetic product formulated with new lipid particles for the treatment of aged skin

BACKGROUND

The cumulative oxidative damage causes an acceleration in the skin aging.

OBJECTIVES

To evaluate the ability of a new patented matrix of lipid particles (SIREN CAPSULE TECHNOLOGY™) to have superior anti-aging properties due to its high sensitivity to reactive oxygen species (ROS), testing its efficacy versus free or encapsulated vitamins.

METHODS

An in vitro study was conducted to evaluate the protective effects of lipid particles using menadione as an enhancer of oxidative stress. Subsequently, in vivo studies evaluated skin hydration, skin barrier function, and smoothness and wrinkle depth. For this purpose, gels containing free or encapsulated vitamins were used as controls.

RESULTS

In vitro, the SIREN CAPSULE TECHNOLOGY™ gel shows inhibitory activity against ROS production through menadione induction. In fact, at both tested concentrations, ROS production is lower than in the control samples (placebo, free vitamins, encapsulated vitamins). In vivo, the net effect of SIREN CAPSULE TECHNOLOGY™ gel versus the others permitted to conclude that lipid particles exert a higher skin moisturizing effect (20.17%) and a stronger effect in reducing transepidermal water loss (-16.29%) after 4 weeks of treatment. As for surface analysis, a gel based on SIREN CAPSULE TECHNOLOGY™ improves the skin texture in a similar way than gel containing encapsulated vitamins (Ra and Rz variations in 4 weeks).

CONCLUSIONS

SIREN CAPSULE TECHNOLOGY™ represents an advance and a successful strategy to develop cosmetic products for the treatment of skin conditions associated with an accumulation of ROS. SIREN CAPSULE TECHNOLOGY™ represents a result-oriented breakthrough in the effective delivery of active ingredients to the skin.

Effect of adjuvant thiamine and ascorbic acid administration on the neurologic outcomes of out-of-hospital cardiac arrest patients: A before-and-after study

AIM

This study aimed to evaluate the impact of early thiamine and ascorbic acid administration on the neurologic outcome in out-of-hospital cardiac arrest (OHCA) patients treated with targeted temperature management (TTM).

METHODS

This before-and-after cohort study used data extracted from two hospitals of the Korean Hypothermia Network prospective registry. The treatment group incorporated patients enrolled from December 2019 to May 2021, that received intravenous thiamine (200 mg) and ascorbic acid (3 g) at 12-hour intervals for a total of six doses. The control group incorporated those enrolled from May 2018 to November 2019. The one-month good neurologic outcome, defined as a Cerebral Performance Category score ≤ 2, between the groups was evaluated using inverse probability of treatment weighting (IPTW).

RESULTS

Among the 234 OHCA survivors with TTM, 102 were included in the treatment group and 132 were included in the control group. The one-month (31.4 % vs. 29.5 %, respectively; P = 0.76) good neurologic outcome rates did not differ between the treatment and control groups. After adjusting using the IPTW, vitamin supplementation was not associated with good neurologic outcome (odds ratio [OR], 1.134; 95 % confidence interval [CI], 0.644-1.999; P = 0.66). In subgroup analysis, vitamin administration was significantly associated with a good neurologic outcome in older (≥65 years) patients (adjusted OR, 5.53; 95 % CI, 1.21-25.23; P = 0.03).

CONCLUSION

Adjuvant thiamine and ascorbic acid administration in OHCA survivors with TTM did not improve their neurologic outcome after one month. Further clinical trials are warranted.

In Vitro α-Glucosidase and α-Amylase Inhibition, Cytotoxicity and Free Radical Scavenging Profiling of the 6-Halogeno and Mixed 6,8-Dihalogenated 2-Aryl-4-methyl-1,2-dihydroquinazoline 3-Oxides

Series of the 6-bromo/iodo substituted 2-aryl-4-methyl-1,2-dihydroquinazoline-3-oxides and their mixed 6,8-dihalogenated (Br/I and I/Br) derivatives were evaluated for inhibitory properties against α-glucosidase and/or α-amylase activities and for cytotoxicity against breast (MCF-7) and lung (A549) cancer cell lines. The 6-bromo-2-phenyl substituted 3a and its corresponding 6-bromo-8-iodo-2-phenyl-substituted derivative 3i exhibited dual activity against α-glucosidase (IC50 = 1.08 ± 0.02 μM and 1.01 ± 0.05 μM, respectively) and α-amylase (IC50 = 5.33 ± 0.01 μM and 1.18 ± 0.06 μM, respectively) compared to acarbose (IC50 = 4.40 ± 0.05 μM and 2.92 ± 0.02 μM, respectively). The 6-iodo-2-(4-fluorophenyl)-substituted derivative 3f, on the other hand, exhibited strong activity against α-amylase and significant inhibitory effect against α-glucosidase with IC50 values of 0.64 ± 0.01 μM and 9.27 ± 0.02 μM, respectively. Compounds 3c, 3l and 3p exhibited the highest activity against α-glucosidase with IC50 values of 1.04 ± 0.03, 0.92 ± 0.01 and 0.78 ± 0.05 μM, respectively. Moderate cytotoxicity against the MCF-7 and A549 cell lines was observed for these compounds compared to the anticancer drugs doxorubicin (IC50 = 0.25 ± 0.05 μM and 0.36 ± 0.07 μM, respectively) and gefitinib (IC50 = 0.19 ± 0.04 μM and 0.25 ± 0.03 μM, respectively), and their IC50 values are in the range of 10.38 ± 0.08-25.48 ± 0.08 μM and 11.39 ± 0.12-20.00 ± 0.05 μM, respectively. The test compounds generally exhibited moderate to strong antioxidant capabilities, as demonstrated via robust free radical scavenging activity assays, viz., DPPH and NO. The potential of selected derivatives to inhibit superoxide dismutase (SOD) was also investigated via enzymatic assay in vitro. Molecular docking revealed the N-O moiety as essential to facilitate electrostatic interactions of the test compounds with the protein residues in the active site of α-glucosidase and α-amylase. The presence of bromine and/or iodine atoms resulted in increased hydrophobic (alkyl and/or π-alkyl) interactions and therefore increased inhibitory effect against both enzymes.

Risk of Hypovitaminosis and Vitamin C Deficiency in Pediatric Patients Undergoing Cardiopulmonary Bypass

Vitamin C levels are known rapidly decrease in adult critical illness. Vitamin C scavenges free radicals, provides critical protection of the endothelial barrier, and improves endothelial responsiveness to catecholamines. Children with congenital heart disease and undergoing cardiac surgery might be at increased risk for low circulating vitamin C levels. A prospective single-center observational study investigated perioperative changes in vitamin C levels in critically ill Children who underwent congenital heart surgery using CPB. Vitamin C serum levels were collected preoperatively and postoperatively (upon admission to the ICU, 24 and 72 h). Linear mixed-effect model was used to estimate mean circulating concentration of vitamin C and to estimate changes in concentration over time. Primary outcome was change in circulating levels of vitamin C before and after CPB. Secondary outcomes were hospital length of stay (LOS), acute kidney injury (AKI), and illness severity. Forty-one patients with a median age of 4.5 [interquartile range (IQR) 2.6-65.6] months at the time of surgery were consented and enrolled. Median CPB duration was 130 [90-175] minutes, and hospital LOS was 9.1 [5.2-19] days. Mean vitamin C levels (μmol/L) before CPB, at PICU admission, 24 h, and 72 h were 82.0 (95% CI 73.4-90.7), 53.4 (95% CI 44.6,62.0), 55.1 (95% CI 46.3,63.8), and 59.2 (95% CI 50.3,68.1), respectively. Upon postoperative admission to the PICU, vitamin C levels decreased by 28.7 (95% CI 20.6-36.8; p < 0.001) μmol/L, whereas levels at 24 and 72 h recovered and did not differ substantially from concentrations reported upon PICU admission (p > 0.15). Changes in vitamin C concentration were not associated with CPB time, STAT mortality category, age, or PIM3. Three patients had post-CPB hypovitaminosis C or vitamin C deficiency. Reduction in vitamin C levels was not associated with hospital LOS (p = 0.673). A 25 μmol/L decrease in vitamin C levels upon PICU admission was associated with developing AKI (aOR = 3.65; 95% CI 1.01-18.0, p = 0.049). Pediatric patients undergoing cardiac surgery with CPB showed decreased vitamin C levels during the immediate postoperative period. Effects of hypovitaminosis C and vitamin C deficiency in this population remain unclear.

Vitamin C may reduce troponin and CKMB levels after PCI and CABG: a meta-analysis

BACKGROUND

Ischemia/reperfusion injury contributes to periprocedural myocardial injury (PMI) in patients undergoing percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG). PMI can be estimated by the elevation of troponin (Tn) and creatine kinase-MB (CKMB) plasma levels, and it is associated with increased risk of cardiovascular events and mortality. Vitamin C might have a beneficial effect on PMI by improving endothelial function, improving myocardial perfusion, and by reducing oxidative stress generated during/after reperfusion. In several small animal models of cardiac stress, vitamin C reduced the increase in Tn and CKMB levels. The aim of this meta-analysis was to investigate whether vitamin C administration may have an effect on Tn and CKMB levels in patients undergoing PCI or CABG.

METHODS

We searched PubMed, Cochrane, Embase and Scopus databases for controlled clinical trials reporting on Tn and CKMB levels in adult patients who underwent PCI or CABG and received vitamin C. As secondary outcomes we collected data on biomarkers of oxidative stress in the included trials. In our meta-analysis, we used the relative scale and estimated the effect as the ratio of means.

RESULTS

We found seven controlled trials which included 872 patients. All included trials administered vitamin C intravenously, with a range from 1 to 16 g/day, and all initiated vitamin administration prior to the procedure. Vitamin C decreased peak Tn plasma levels in four trials on average by 43% (95% CI: 13 to 63%, p = 0.01) and peak CKMB plasma levels in five trials by 14% (95% CI: 8 to 21%, p < 0.001). Vitamin C also significantly decreased the biomarkers of oxidative stress.

CONCLUSIONS

Vitamin C may decrease cardiac enzyme levels in patients undergoing elective PCI or CABG. This may be explained partially by its antioxidant effects. Our findings encourage further research on vitamin C administration during cardiac procedures and in other clinical contexts that increase the level of cardiac enzymes. Future studies should search for an optimal dosing regimen, taking baseline and follow-up plasma vitamin C levels into account.

Effect of high-dose intravenous ascorbic acid on microcirculation and endothelial glycocalyx during sepsis and septic shock: a double-blind, randomized, placebo-controlled study

Previous studies indicate supplemental vitamin C improves microcirculation and reduces glycocalyx shedding in septic animals. Our randomized, double-blind, placebo-controlled trial aimed to investigate whether a high dose of intravenous ascorbic acid (AA) might improve microcirculation and affect glycocalyx in septic patients. In our study, 23 septic patients were supplemented with a high dose (50 mg/kg every 6 h) of intravenous AA or placebo for 96 h. Sublingual microcirculation was examined using a handheld Cytocam-incident dark field (IDF) video microscope. A sidestream dark field video microscope (SDF), connected to the GlycoCheck software (GlycoCheck ICU®; Maastricht University Medical Center, Maastricht, the Netherlands), was employed to observe glycocalyx. We found a significantly higher proportion of perfused small vessels (PPV) 6 h after the beginning of the trial in the experimental group compared with placebo. As an indicator of glycocalyx thickness, the perfused boundary region was lower in capillaries of the 5-9 μm diameter in the AA group than placebo after the first dose of AA. Our data suggest that high-dose parenteral AA tends to improve microcirculation and glycocalyx in the early period of septic shock. The study was retrospectively registered in the clinicaltrials.gov database on 26/02/2021 (registration number NCT04773717).

Associations of serum vitamin C concentrations with risk of all-cause and cause-specific mortality among individuals with and without type 2 diabetes

PURPOSE

Compared with people without diabetes, people with type 2 diabetes (T2D) are at higher risk of both subnormal vitamin C status and increased oxidative stress. We aimed to investigate the associations of serum vitamin C concentrations with all-cause and cause-specific mortality among adults with and without T2D.

METHODS

The current analysis included 20,045 adults (2691 people with T2D and 17,354 without T2D) from the Third National Health and Nutrition Examination Survey (NHANES III) and NHANES 2003-2006. Cox proportional hazards regression models were applied to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). Restricted cubic spline analyses were used to examine the dose-response relationship.

RESULTS

After a median follow-up of 17.3 years, 5211 deaths were documented. Individuals with T2D had a lower level of serum vitamin C concentrations compared with those without T2D (the median value: 40.1 vs. 44.9 μmol/L). Furthermore, the dose-response relationship between serum vitamin C and mortality showed different patterns between participants with and without T2D. In individuals without T2D, there was a nonlinear association of serum vitamin C concentrations with all-cause, cancer, and CVD mortality, with the lowest risk around a serum vitamin C concentration of 48.0 μmol/L (all Poverall < 0.05, Pnonlinearity < 0.05). In contrast, among those with T2D in the similar concentration range, higher serum vitamin C levels (ranged from 0.46 to 116.26 μmol/L) were linearly associated with lower all-cause and cancer mortality (both Poverall < 0.05, Pnonlinearity > 0.05). Significant additive interaction was observed between diabetes status and serum vitamin C levels with regard to all-cause and cancer mortality (P < 0.001). In addition, C-reactive protein, gamma-glutamyl transpeptidase, and HbA1c explained 14.08, 8.96, and 5.60% of the association between serum vitamin C and all-cause mortality among individuals with T2D, respectively.

CONCLUSIONS

Higher serum vitamin C concentrations were significantly associated with lower risk of mortality in participants with T2D in a linear dose-response manner, while a nonlinear association was observed in participants without T2D, with an apparent threshold around 48.0 μmol/L. These findings suggest that the optimal vitamin C requirement may differ in individuals with and without T2D.

The effect of vitamin C in adults with sepsis: a meta-analysis of randomized controlled trials

Background

The effect of intravenous (IV) vitamin C in the treatment of sepsis remains controversial. We aimed to explore the clinical efficacy of vitamin C in the treatment of sepsis.

Methods

Electronic databases (PubMed, Embase, Web of Science, and Cochrane Library) were searched from inception through November 15th, 2022, for randomized controlled trials evaluating the effect of IV vitamin C treatment in patients with sepsis. The primary outcome was short-term mortality, secondary outcomes included duration of vasopressor use, length of intensive care unit (ICU) stay, and Sequential Organ Failure Assessment (SOFA) score after vitamin C treatment. Subgroup analyses were performed based on the dose and duration of IV vitamin C and region to determine whether vitamin C benefited patients with sepsis.

Results

A total of 10 studies including 1,426 patients fulfilled the predefined criteria and were analyzed. Overall, there were no significant differences between the vitamin C group and the control group regarding short-term mortality [odds ratio (OR), 0.61; 95% confidence interval (CI) 0.37-1.01; p = 0.05], ICU length of stay [mean difference (MD), -1.24; 95% CI -3.54 to 1.05, p = 0.29] and SOFA score (MD, -0.85, 95% CI -2.38 to 0.67, p = 0.27). However, vitamin C significantly reduced the duration of vasopressor use (MD, -14.36, 95% CI -26.11 to -2.61, p = 0.02). Furthermore, subgroup analysis found that in developing countries, vitamin C was associated with a significant reduction in short-term mortality (OR, 0.33; 95% CI 0.12-0.90; p = 0.03), duration of vasopressor use (MD, -24.37, 95% CI -33.72 to -15.02, p < 0.001) and SOFA score (MD, -2.55, 95% CI -4.81 to -0.28, p = 0.03).

Conclusion

In our study, vitamin C administration for sepsis patients was not associated with a significant reduction in short-term mortality, length of ICU stay or SOFA score. However, we observed that vitamin C could reduce the duration of vasopressor use. Furthermore, sepsis patients in developing countries may benefit more from vitamin C administration than those in developed countries.Systematic review registration: Identifier CRD42022380958, https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=380958.

Neutrophils and the Systemic Inflammatory Response Syndrome (SIRS)

We are not entirely able to understand, assess, and modulate the functioning of the immune system in clinical situations that lead to a systemic inflammatory response. In the search for diagnostic and treatment strategies (which are still far from perfect), it became very important to study the pathogenesis and participation of endogenous inflammation mediators. This study attempts to more precisely establish the role of neutrophils in individual phenomena occurring during an inflammatory and anti-inflammatory reaction, taking into account their cidal, immunoregulatory, and reparative abilities. Pro- and anticoagulatory properties of endothelium in systemic inflammatory response syndrome (SIRS) are emphasised, along with the resulting clinical implications (the application of immunotherapy using mesenchymal stem/stromal cells (MSCs) or IL-6 antagonists in sepsis and COVID-19 treatment, among others). Special attention is paid to reactive oxygen species (ROS), produced by neutrophils activated during "respiratory burst" in the course of SIRS; the protective and pathogenic role of these endogenous mediators is highlighted. Moreover, clinically useful biomarkers of SIRS (neutrophil extracellular traps, cell-free DNA, DAMP, TREMs, NGAL, miRNA, selected cytokines, ROS, and recognised markers of endothelial damage from the group of adhesins by means of immunohistochemical techniques) related to the neutrophils are presented, and their role in the diagnosing and forecasting of sepsis, burn disease, and COVID-19 is emphasised. Finally, examples of immunomodulation of sepsis and antioxidative thermal injury therapy are presented.

Effect of intravenous vitamin C on adult septic patients: a systematic review and meta-analysis

Background

An increasing number of studies indicate that vitamin C (VC) reduces the mortality of adult septic patients, while some articles suggest otherwise. We performed this systematic review and meta-analysis to resolve the discrepancies in reported results concerning the efficacy of VC in septic patients.

Methods

We comprehensively searched MEDLINE, EMBASE, and the Cochrane Central Register of Controlled trials for randomized controlled trials (RCTs) evaluating the efficacy of intravenous VC (IVVC) on adult septic patients published from inception to November 28, 2022. The quality of outcomes for eligible studies was assessed using the Recommendations Assessment, Development, and Evaluation methodology. The results were analyzed using the pooled mean difference (MD) or risk ratio (RR) and 95% confidence intervals (CIs).

Results

Twenty-two studies (3,570 adult septic patients) were included. IVVC treatment did not improve 28-day mortality compared to the control group (RR, 0.92; 95% CI, 0.81-1.04; I2 = 26%; evidence risk, moderate). IVVC monotherapy decreased mortality (RR, 0.69; 95% CI, 0.52-0.93; I2 = 57%), whereas combination therapy did not affect mortality (RR, 1.03; 95% CI, 0.90-1.17; I2 =0%). IVVC had a trend to decrease the mortality of septic patients (RR, 0.83; 95% CI, 0.69-1.00; I2 = 33%) but did not affect septic shock patients (RR, 1.01; 95% CI, 0.85-1.21; I2 = 18%). IVVC reduced the duration of vasopressor use (MD, -8.45; 95% CI, -15.43 to -1.47; evidence risk, very low) but did not influence the incidence of AKI, ICU length of stay, duration of mechanical ventilation.

Conclusions

IVVC treatment did not improve the 28-day mortality in septic patients. Subgroup analysis indicated that VC had a trend to decrease the 28-day mortality in patients with sepsis but not septic shock. IVVC monotherapy, rather than combination therapy, decreased the 28-day mortality in septic patients. The findings imply that Hydrocortisone, Ascorbic acid, Thiamine (HAT) combination therapy is not superior to IVVC monotherapy for septic patients. These findings warrant further confirmation in future studies, which should also investigate the mechanisms underlying the enhanced efficacy of IVVC monotherapy in septic patients.

Systematic review registration

https://inplasy.com/.

Oleanolic acid inhibits mercury chloride induced-liver ferroptosis by regulating ROS/iron overload

Mercury chloride can cause severe liver injury, which involves multiple mechanisms. Ferroptosis plays an important role in regulating the development and progression of liver pathology. Oleanolic acid (OA), a triterpenoid compound widely exists in fruits, has liver protective properties. In this study, we investigated the role of ferroptosis in mercury chloride-induced liver injury and the intervention effect of OA, and clarified the potential mechanism. We found that mercury chloride-induced oxidative stress in liver tissues and cells, leading to lipid peroxidation and iron overload, thereby reducing the expression levels of GPX4 and SLC7A11, and increasing the expression level of TRF1, OA pretreatment improved the changes of GPX4, SLC7A11 and TRF1 induced by mercury chloride, which were related to its inhibition of oxidative stress. Furthermore, We pretreated cells with OA, VC, and Fer-1, respectively and found that VC pretreatment reduced oxidative stress and significantly reversed the gene and protein expressions of GPX4, SLC7A11, and TRF1 in mercury chloride-exposed cells (P < 0.05, vs. HgCl₂ group), however, the protein expression level of GPX4 in OA pre-treatment group was lower than that in VC pre-treatment group (P < 0.05). Fer-1 pretreatment decreased the level of iron ions in cells, increased the gene and protein expression levels of GPX4 and SLC7A11, and decreased the gene and protein expression levels of TRF1 (P < 0.05, vs. HgCl₂ group), however, the protein expression levels of GPX4 and SLC7A11 in OA pre-treatment group were lower than those in Fer-1 pre-treatment group (P < 0.05). Moreover, vivo experiments also demonstrated that pre-treatment with OA, VC, and Fer-1 reversed the changes in gene expression levels of Nrf2 and SOD1, and protein expression of GPX4 induced by mercury chloride (P < 0.05, vs. HgCl₂ group), meanwhile, the difference was not statistically significant among OA, VC, and Fer-1 pretreatment. The improvement effect of OA pretreatment on the change in TFR1 protein expression caused by mercury chloride was similar to that of Fer-1 and VC, however, the intervention effect of OA on SLC7A11 protein expression was not as good as Fer-1 and VC pre-treatment. To sum up, all these results suggest that ferroptosis is involved in mercury chloride-induced liver injury, OA pretreatment alleviated mercury chloride-induced ferroptosis by inhibiting ROS production and iron ion overload, and then alleviate the liver injury.

The Evolving Role of Proteins in Wearable Sweat Biosensors

Sweat is an increasingly popular biological medium for fitness monitoring and clinical diagnostics. It contains an abundance of biological information and is available continuously and noninvasively. Sweat-sensing devices often employ proteins in various capacities to create skin-friendly matrices that accurately extract valuable and time-sensitive information from sweat. Proteins were first used in sensors as biorecognition elements in the form of enzymes and antibodies, which are now being tuned to operate at ranges relevant for sweat. In addition, a range of structural proteins, sometimes assembled in conjunction with polymers, can provide flexible and compatible matrices for skin sensors. Other proteins also naturally possess a range of functionalities─as adhesives, charge conductors, fluorescence emitters, and power generators─that can make them useful components in wearable devices. Here, we examine the four main components of wearable sweat sensors─the biorecognition element, the transducer, the scaffold, and the adhesive─and the roles that proteins have played so far, or promise to play in the future, in each component. On a case-by-case basis, we analyze the performance characteristics of existing protein-based devices, their applicable ranges of detection, their transduction mechanism and their mechanical properties. Thereby, we review and compare proteins that can readily be used in sweat sensors and others that will require further efforts to overcome design, stability or scalability challenges. Incorporating proteins in one or multiple components of sweat sensors could lead to the development and deployment of tunable, greener, and safer biosourced devices.

Effect of breathing exercises on oxidative stress biomarkers in humans: A systematic review and meta-analysis

Background

Breathing exercises improve oxidative stress in healthy young adults and patients with diabetes, hypertension, and chronic obstructive pulmonary disease. Furthermore, the mechanism of respiratory intervention is controversial. Therefore, in this meta-analysis, we aimed to systematically evaluate the effects of breathing exercises on oxidative stress biomarkers in humans and provide evidence for the clinical application of breathing exercises.

Methods

The Embase, PubMed, Cochrane Library, Web of Science, CNKI, and WANFANG databases were searched for studies about the effects of breathing exercises on human oxidative stress levels, with no restraints regarding time, race, or language. The experimental group included various breathing exercises, and the outcome index included malondialdehyde, superoxide dismutase, and glutathione, nitric oxide, vitamin C, or total antioxidant capacity levels from a randomized controlled trial. Data were extracted by more than two authors and reviewed by one author.

Results

Ten studies were included from five countries. Data from patients with no disease, chronic obstructive pulmonary disease, hypertension, or diabetes were included. Participants who performed breathing exercises had greater changes in the included biomarkers than those who did not, suggesting that these biomarkers can be used to evaluate oxidative stress after respiratory interventions.

Conclusion

Breathing exercises increased SOD and GSH activities and decreased MDA content.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022337119, identifier CRD42022337119.

Protective effect of dihydromyricetin on vascular smooth muscle cell apoptosis induced by hydrogen peroxide in rats

OBJECTIVE

Dihydromyricetin (DMY), also called Ampelopsin, which was extracted from Ampelopsis grossedentata, has been demonstrated to have a protective effect against cell oxidative injury and cell apoptosis in vitro. In the present study, we tried to study the role of DMY on apoptosis of vascular smooth muscle cells (VSMCs) induced by hydrogen peroxide (H₂O₂) and explore the underlying mechanisms.

METHODS

Apoptotic cells were detected by Hematoxylin and Eosin (H.E.) staining, Hoechst 33342 staining, and Annexin V-fluorescein isothiocyanate binding assay. The intracellular reactive oxygen species (ROS) level was estimated through fluorescence assay. The mRNA and protein expression of Caspase-3, Caspase-9, Bcl-2, and Bax were determined by reverse transcription-polymerase chain reaction (RT-PCR) and western blot.

RESULTS

The results showed that the pretreatment of VSMCs with DMY not only significantly increased cell viability, reduced intracellular ROS release, alleviated the morphological changes of apoptosis, and decreased the apoptosis rate, but also upregulated Bcl-2 expression and downregulated Caspase-3, Caspase-9, Bax expression, and ultimately attenuated the H₂O₂-stimulated apoptosis.

CONCLUSION

The inhibition of DMY on VSMC apoptosis may be mediated by ROS scavenging and the activation of the mitochondrial apoptotic signaling pathway.

Impact of intravenous vitamin C as a monotherapy on mortality risk in critically ill patients: A meta-analysis of randomized controlled trials with trial sequential analysis

Background

This meta-analysis aimed at investigating the pooled evidence regarding the effects of intravenous vitamin C (IVVC) on mortality rate in critically ill patients.

Methods

Databases including Medline, Embase, and Cochrane Library were searched from inception to October, 2022 to identify RCTs. The primary outcome was the risk of overall mortality. Subgroup analyses were performed based on IVVC dosage (i.e., cut-off value: 100 mg/kg/day or 10000 mg/day). Trial sequential analysis (TSA) was used to examine the robustness of evidence.

Results

A total of 12 trials including 1,712 patients were analyzed. Although meta-analysis demonstrated a lower risk of mortality in patients with IVVC treatment compared to those without [risk ratio (RR): 0.76, 95% CI: 0.6 to 0.97, p = 0.02, I2 = 36%, 1,711 patients), TSA suggested the need for more studies for verification. Moreover, subgroup analyses revealed a reduced mortality risk associated with a low IVVC dosage (RR = 0.72, p = 0.03, 546 patients), while no beneficial effect was noted with high IVVC dosage (RR = 0.74, p = 0.13, I2 = 60%, 1,165 patients). The durations of vasopressor [mean difference (MD): −37.75 h, 404 patients) and mechanical ventilation (MD: −47.29 h, 388 patients) use were shorter in the IVVC group than those in the controls, while there was no significant difference in other prognostic outcomes (e.g., length of stay in intensive care unit/hospital) between the two groups.

Conclusion

Although intravenous vitamin C as a monotherapy reduced pooled mortality, durations of vasopressor use and mechanical ventilation, further research is required to support our findings and to identify the optimal dosage of vitamin C in the critical care setting.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42022371090.

Effects of hydrocortisone combined with vitamin C and vitamin B1 versus hydrocortisone alone on microcirculation in septic shock patients: A pilot study

OBJECTIVE

To investigate the effects of hydrocortisone combined with vitamin C and vitamin B1 versus hydrocortisone on sublingual microcirculation in septic shock patients.

METHODS

This pilot study enrolled septic shock patients admitted to the ICU of a tertiary teaching hospital from February 2019 to January 2020. We randomly assigned the enrolled patients to the treatment group (hydrocortisone combined with vitamin C and vitamin B1 added to standard care) and the control group (hydrocortisone alone added to standard care) in a 1 : 1 ratio. The primary outcome was perfused small vascular density (sPVD) monitored by a sublingual microcirculation imaging system at 24 hours after treatment.

RESULTS

Twelve patients in the treatment group and ten in the control group completed the study. The baseline characteristics were comparable between the groups. No statistically significant difference was found in the sPVD between the groups at baseline. The sPVD in the treatment group was significantly higher than that in the control group at 4 hours after treatment (mean difference, 7.042; 95% CI, 2.227-11.857; P = 0.009) and 24 hours after treatment (mean difference, 7.075; 95% CI, 2.390-11.759; P = 0.008).

CONCLUSIONS

Compared with hydrocortisone, hydrocortisone combined with vitamin C and vitamin B1 significantly improves microcirculation in septic shock patients.

Integrated Analysis of Tracheobronchial Fluid from Before and After Cardiopulmonary Bypass Reveals Activation of the Integrated Stress Response and Altered Pulmonary Microvascular Permeability

Objective: We aim to comprehensively describe the transcriptional activity and signaling of pulmonary parenchymal and immune cells before and after cardiopulmonary bypass (CPB) by using a multi-omic approach coupled with functional cellular assays. We hypothesize that key signaling pathways from specific cells within the lung alter pulmonary endothelial cell function resulting in worsening or improving disease. Methods: We collected serial tracheobronchial lavage samples from intubated patients less than 2-years-old undergoing surgery with CPB. Samples were immediately processed for single cell RNA sequencing (10x Genomics). Cell clustering, cell-type annotation, and visualization were performed, and differentially expressed genes (DEG) between serial samples were identified. Metabolomic and proteomic analyses were performed on the supernatant using mass spectrometry and a multiplex assay (SomaScan) respectively. Functional assays were done using electric cell-substrate impedance sensing to measure resistance across human pulmonary microvascular endothelial cells (HPMECs). Results: Analysis of eight patients showed a heterogeneous mixture of pulmonary parenchymal and immune cells. Cell clustering demonstrated time-dependent changes in the transcriptomic signature indicating altered cellular phenotypes after CPB. DEG analysis was represented by genes involved in host defense, innate immunity, and the mitochondrial respiratory transport chain. Ingenuity pathway analysis showed upregulation of the integrated stress response across all cell types after CPB. Metabolomic analysis demonstrated upregulation of ascorbate and aldarate metabolism. Unbiased proteomic analysis revealed upregulation of proteins involved in cytokine and chemokine pathways. Post-CPB patient supernatant improved HMPEC barrier function, suggesting a protective cellular response to CPB. Conclusion: Children who undergo CPB for cardiac surgery have distinct cell populations, transcriptional activity, and metabolism that change over time. The response to ischemia-reperfusion injury in the lower airway of children appears to be protective, with the need to identify potential targets through future investigations.

The effects of vitamin C on respiratory, allergic and immunological diseases: an experimental and clinical-based review

Vitamin C is used in modern medicine supplements for treatment of various disorders associated with oxidative stress, inflammation and immune dysregulation. In this review article, experimental and clinical results regarding the effects of vitamin C on respiratory immunologic, and allergic diseases are reviewed. Various databases and appropriate keywords are used to search the effect of vitamin C on respiratory diseases until the end of May 2022. Books, theses and articles were included. These studies assessed the effects of vitamin C on respiratory disorders including asthma, chronic obstructive pulmonary disease (COPD), lung infection and lung cancer. Vitamin C showed relaxant effect on tracheal smooth muscle via various mechanisms. The preventive effects of vitamin C were mediated by antioxidant, immunomodulatory and anti-inflammatory mechanisms in the experimental animal models of different respiratory diseases. Some clinical studies also indicated the effect of vitamin C on lung cancer and lung infections. Therefore, vitamin C could be used a preventive and/or relieving therapy in respiratory diseases.

Metabolic resuscitation therapy in critically ill patients with sepsis and septic shock: A pilot prospective randomized controlled trial

The main purpose of our research was to further clarify the effectiveness and potential pathophysiological principles of metabolic resuscitation therapy in critically ill patients with sepsis and septic shock. We found that metabolic resuscitation therapy is beneficial for patients with sepsis and septic shock, shortening the length of intensive care unit (ICU) stay, reducing the duration of vasopressor use, and reducing the ICU mortality rate of patients with sepsis and septic shock, but it does not reduce the hospital mortality rate.

Immunological responses of septic rats to combination therapy with thymosin α1 and vitamin C

This study investigated the effect of combined thymosin α1 and vitamin C (Tα1 + VitC) on the immunological responses of septic rats. Five groups were designed. The septic model was established by the cecal ligation puncture (CLP) method. The sham group did not undergo CLP, the model group was given normal saline solution, the Tα1 group was given Tα1 (200 µg/kg), the VitC group was given VitC (200 mg/kg), and the Tα1 + VitC group was given Tα1 + VitC. Specimens for immunological analyses were collected at 6, 12, 24, and 48 h posttreatment in each group except for the sham group (only at 48 h). CD4 + CD25 + T cells in the peripheral blood and dendritic cell (DC) proportions in the spleen were analyzed by flow cytometry. Tumor necrosis factor α (TNF-α), interleukin 6 (IL-6), transforming growth factor-β (TGF-ß1), and nuclear factor kappa-B (NF-κB) were measured by ELISA. CD4 + CD25 + T cells and OX62 + DCs levels significantly increased in the model group and decreased in the Tα1 and/or VitC treatment groups. Similarly, the levels of TNF-α, IL-6, TGF-ß1, and NF-κB significantly increased in the model group and decreased in the Tα1, VitC, and Tα1 + VitC groups, indicating that combined Tα1 and VitC therapy may help regulate the immunological state of patients with sepsis, thereby improving prognosis.

History of scurvy and use of vitamin C in critical illness: A narrative review

In 1747, an important milestone in the history of clinical research was set, as the Scottish surgeon James Lind conducted the first randomized controlled trial. Lind was interested in scurvy, a severe vitamin C deficiency which caused the death of thousands of British seamen. He found that a dietary intervention with oranges and lemons, which are rich in vitamin C by nature, was effective to recover from scurvy. Because of its antioxidative properties and involvement in many biochemical processes, the essential micronutrient vitamin C plays a key role in the human biology. Moreover, the use of vitamin C in critical illness-a condition also resulting in death of thousands in the 21st century-has gained increasing interest, as it may restore vascular responsiveness to vasoactive agents, ameliorate microcirculatory blood flow, preserve endothelial barriers, augment bacterial defense, and prevent apoptosis. Because of its redox potential and powerful antioxidant capacity, vitamin C represents an inexpensive and safe antioxidant, with the potential to modify the inflammatory cascade and improve clinical outcomes of critically ill patients. This narrative review aims to update and provide an overview on the role of vitamin C in the human biology and in critically ill patients, and to summarize current evidence on the use of vitamin C in diverse populations of critically ill patients, in specific focusing on patients with sepsis and coronavirus disease 2019.

An update of the effects of vitamins D and C in critical illness

Many critically ill patients are vitamin D and vitamin C deficient and the current international guidelines state that hypovitaminoses should be compensated. However, uncertainty about optimal dosage, timing and indication exists in clinical routine, mainly due to the conflicting evidence. This narrative review discusses both micronutrients with regards to pathophysiology, clinical evidence of benefits, potential risks, and guideline recommendations. Evidence generated from the most recent clinical trials are summarized and discussed. In addition, pragmatic tips for the application of these vitamins in the clinical routine are given. The supplementations of vitamin D and C represent cost-effective and simple interventions with excellent safety profiles. Regarding vitamin D, critically ill individuals require a loading dose to improve 25(OH)D levels within a few days, followed by a daily or weekly maintenance dose, usually higher doses than healthy individuals are needed. For vitamin C, dosages of 100-200 mg/d are recommended for patients receiving parenteral nutrition, but needs may be as high as 2-3 g/d in acutely ill patients.

The Effect of Drugs with α-Glutamyl-Tryptophan for Cytokine Secretion and Level of Surface Molecule ICAM-1 In Vitro

The study of the molecular mechanisms underlying the action of immunomodulatory drugs is important for substantiating their therapeutic effect. In the present work, spontaneous and TNFα-induced secretion of IL-1α and IL-8 pro-inflammatory cytokines, as well as the level of the ICAM-1 adhesion molecule in EA.hy 926 endothelial cell culture and peripheral blood mononuclear cells of healthy donors, is studied using an in vitro model of inflammation in the presence of α-glutamyl-tryptophan (α-Glu-Trp) and Cytovir-3. The aim was to evaluate cellular mechanisms mediating the immunomodulatory effect of α-Glu-Trp and Cytovir-3 drugs. It was shown that α-Glu-Trp reduced TNFα-induced IL-1α production and increased TNFα-stimulated level of the ICAM-1 surface molecule of endothelial cells. At the same time, the drug reduced secretion of the IL-8 cytokine induced by TNFα and increased the spontaneous level of ICAM-1 in mononuclear cells. Cytovir-3 had an activating effect on EA.hy 926 endothelial cells and human peripheral blood mononuclear leukocytes. In its presence, there was an increase in the spontaneous secretion of IL-8 by endothelial and mononuclear cells. In addition, Cytovir-3 increased the level of TNFα-induced ICAM-1 on endothelial cells and increased the spontaneous level of this surface molecule on mononuclear cells. Suppression of stimulated production of pro-inflammatory cytokines under the action of α-Glu-Trp both separately and as a part of Cytovir-3 may determine its anti-inflammatory properties. However, an increased level of the surface ICAM-1 molecule indicates mechanisms that enhance the functional activity of these cells, which is equally important for the implementation of an effective immune response to infection and repair of damaged tissues during inflammatory response.

High-Dose Intravenous Ascorbate in Sepsis, a Pro-Oxidant Enhanced Microbicidal Activity and the Effect on Neutrophil Functions

Vitamin C (ascorbic acid), a water-soluble essential vitamin, is well-known as an antioxidant and an essential substrate for several neutrophil functions. Because of (i) the importance of neutrophils in microbial control and (ii) the relatively low vitamin C level in neutrophils and in plasma during stress, vitamin C has been studied in sepsis (a life-threatening organ dysfunction from severe infection). Surprisingly, the supraphysiologic blood level of vitamin C (higher than 5 mM) after the high-dose intravenous vitamin C (HDIVC) for 4 days possibly induces the pro-oxidant effect in the extracellular space. As such, HDIVC demonstrates beneficial effects in sepsis which might be due to the impacts on an enhanced microbicidal activity through the improved activity indirectly via enhanced neutrophil functions and directly from the extracellular pro-oxidant effect on the organismal membrane. The concentration-related vitamin C properties are also observed in the neutrophil extracellular traps (NETs) formation as ascorbate inhibits NETs at 1 mM (or less) but facilitates NETs at 5 mM (or higher) concentration. The longer duration of HDIVC administration might be harmful in sepsis because NETs and pro-oxidants are partly responsible for sepsis-induced injuries, despite the possible microbicidal benefit. Despite the negative results in several randomized control trials, the short course HDIVC might be interesting to use in some selected groups, such as against anti-biotic resistant organisms. More studies on the proper use of vitamin C, a low-cost and widely available drug, in sepsis are warranted.

Chemical signaling in the developing avian retina: Focus on cyclic AMP and AKT-dependent pathways

Communication between developing progenitor cells as well as differentiated neurons and glial cells in the nervous system is made through direct cell contacts and chemical signaling mediated by different molecules. Several of these substances are synthesized and released by developing cells and play roles since early stages of Central Nervous System development. The chicken retina is a very suitable model for neurochemical studies, including the study of regulation of signaling pathways during development. Among advantages of the model are its very well-known histogenesis, the presence of most neurotransmitter systems found in the brain and the possibility to make cultures of neurons and/or glial cells where many neurochemical functions develop in a similar way than in the intact embryonic tissue. In the chicken retina, some neurotransmitters or neuromodulators as dopamine, adenosine, and others are coupled to cyclic AMP production or adenylyl cyclase inhibition since early stages of development. Other substances as vitamin C and nitric oxide are linked to the major neurotransmitter glutamate and AKT metabolism. All these different systems regulate signaling pathways, including PKA, PKG, SRC, AKT and ERK, and the activation of the transcription factor CREB. Dopamine and adenosine stimulate cAMP accumulation in the chick embryo retina through activation of D1 and A2a receptors, respectively, but the onset of dopamine stimulation is much earlier than that of adenosine. However, adenosine can inhibit adenylyl cyclase and modulate dopamine-dependent cAMP increase since early developmental stages through A1 receptors. Dopamine stimulates different PKA as well as EPAC downstream pathways both in intact tissue and in culture as the CSK-SRC pathway modulating glutamate NMDA receptors as well as vitamin C release and CREB phosphorylation. By the other hand, glutamate modulates nitric oxide production and AKT activation in cultured retinal cells and this pathway controls neuronal survival in retina. Glutamate and adenosine stimulate the release of vitamin C and this vitamin regulates the transport of glutamate, activation of NMDA receptors and AKT phosphorylation in cultured retinal cells. In the present review we will focus on these reciprocal interactions between neurotransmitters or neuromodulators and different signaling pathways during retinal development.

Updates in the Management of Perioperative Vasoplegic Syndrome

Vasoplegic syndrome occurs relatively frequently in cardiac surgery, liver transplant, major noncardiac surgery, in post-return of spontaneous circulation situations, and in pateints with sepsis. It is paramount for the anesthesiologist to understand both the pathophysiology of vasoplegia and the different treatment strategies available for rescuing a patient from life-threatening hypotension.

Oxidative Stress as a Therapeutic Target of Cardiac Remodeling

Cardiac remodeling is defined as a group of molecular, cellular, and interstitial changes that clinically manifest as changes in the heart's size, mass, geometry, and function after different stimuli. It is important to emphasize that remodeling plays a pathophysiological role in the onset and progression of ventricular dysfunction and subsequent heart failure. Therefore, strategies to mitigate this process are critical. Different factors, including neurohormonal activation, can regulate the remodeling process and increase cell death, alterations in contractile and regulatory proteins, alterations in energy metabolism, changes in genomics, inflammation, changes in calcium transit, metalloproteases activation, fibrosis, alterations in matricellular proteins, and changes in left ventricular geometry, among other mechanisms. More recently, the role of reactive oxygen species and oxidative stress as modulators of remodeling has been gaining attention. Therefore, this review assesses the role of oxidative stress as a therapeutic target of cardiac remodeling.

Analysis of Efficacy of Ascorbic Acid, Hydrocortisone and Thiamine as a Part Adjuvant Therapy of Sepsis and Septic Shock

The objective: to analyze efficacy of ascorbic acid or its combination with glucocorticoids and thiamine on clinical outcomes in patients with sepsis and septic shock.

Subjects and Methods. The literature search was carried out in the database of MEDLINE, Embase, and the Cochrane Library systems. It is limited to published articles from January 1, 2008 to March 1, 2022. The selection criteria were observational studies in patients over 18 years of age with septic shock, if they provide data on the use of ascorbic acid in the form of monotherapy or in combination with hydrocortisone and thiamine.

Conclusion. The review includes 18 publications, including 3 meta-analyses on the use of ascorbic acid or its combination with hydrocortisone and thiamine in patients in the adjuvant therapy program for sepsis and septic shock. Clinical efficacy has been proven in 11 studies. However, 7 publications did not show global changes in the outcomes of sepsis and septic shock therapy compared to basic therapy. Currently, there is a need for further research.

Vitamin C mitigates hematological and biochemical alterations caused by di(2-ethylhexyl) phthalate toxicity in female albino mice, Mus musculus

Di(2-ethylhexyl) phthalate (DEHP) is ubiquitous environmental contaminant and identified as endocrine-disrupting chemical (EDC), present in plastics as plasticizer. Due to its versatile use, human exposure level reaches to danger limit. The main focus of our study is to see the effect of vitamin C on hematological and biochemical alterations caused by Di(2-ethylhexyl) Phthalate toxicity in female albino mice, Mus musculus. It is found to cause defects of the liver, kidney, and lungs. Its anti-androgenic nature brings the main focus on its toxicity associated with reproductive and endocrine system. In this experimental study, 18 young female Swiss albino mice, Mus musculus, were used and divided into 3 groups of 6 animals each as control (corn oil vehicle), DEHP group (100 mg/kg body weight dissolved in corn oil), and DEHP + vitamin-C group (100 mg/kg body weight each, dissolved in corn oil and double distilled water, respectively) for 90 days. In this research, serum metabolites were evaluated to study the effect of DEHP on glucose, total protein, and lipid profile along with some hematological, enzymological, and oxidative stress parameters. Simultaneously, we compared the effectiveness of vitamin-C against DEHP toxicity to mitigate the serum homeostasis disturbance. In present study, we observed, in DEHP-treated animals, glucose, triglycerides, very-low-density lipoprotein (VLDL), total protein, alkaline phosphatase (ALP), acid phosphatase (ACP), and alanine aminotransferase (ALT) levels increased remarkably, whereas total cholesterol, high-density lipoproteins (HDL), aspartate aminotransferase (AST), total RBC count, total WBC count, and hemoglobin (Hb) level significantly decreased as compared to control group. In addition, we noticed there was a decrease in superoxide dismutase (SOD) and increase in levels of lipid peroxidation (MDA) and interleukin-6 (IL-6) in DEHP treatment group as compared to control group. The results indicated vitamin C had a better improving effect against DEHP toxicity on balancing metabolic abnormalities and inflammation-related comorbidities.

Functional constituents of plant-based foods boost immunity against acute and chronic disorders

Plant-based foods are becoming an increasingly frequent topic of discussion, both scientific and social, due to the dissemination of information and exchange of experiences in the media. Plant-based diets are considered beneficial for human health due to the supply of many valuable nutrients, including health-promoting compounds. Replacing meat-based foods with plant-based products will provide many valuable compounds, including antioxidants, phenolic compounds, fibers, vitamins, minerals, and some ω3 fatty acids. Due to their high nutritional and functional composition, plant-based foods are beneficial in acute and chronic diseases. This article attempts to review the literature to present the most important data on nutrients of plant-based foods that can then help in the prevention of many diseases, such as different infections, such as coronavirus disease, pneumonia, common cold and flu, asthma, and bacterial diseases, such as bronchitis. A properly structured plant-based diet not only provides the necessary nutrients but also can help in the prevention of many diseases.

High-dose vitamin C on sepsis: Protocol of a prospective, multi-centered, double-blinded, randomized, and placebo-controlled superiority study

Background

Sepsis is an inflammatory syndrome with life-threatening organ dysfunction and high mortality. In the recent 10 years, high-dose intravenous injection of vitamin C, the first-line antioxidant of humans, has received highlighted attention in the field of critical care. The study aims to examine the efficacy and safety of high-dose intravenous injection of vitamin C in the treatment of sepsis.

Methods and design

Here, we are conducting a prospective, multi-centered, double-blinded, randomized, and placebo-controlled superiority study named High-Dose Vitamin C on Sepsis (HDVCOS). A total of 620 participants diagnosed with sepsis in four participating sites across China that satisfy the eligibility criteria will be randomized at a ratio of 1:1 to receive treatment with a high-dose intravenous injection of vitamin C (200 mg/kg/24 h) or placebo (saline) for 4 days. The primary outcome is 28 days of mortality. The secondary outcomes include the incidence of organ failure, Sequential Organ Failure Assessment (SOFA) score change, organ support, the relationship between plasma vitamin C concentration and outcomes, and adverse events.

Conclusion

The findings of this study will provide potential evidence for high-dose intravenous injection of vitamin C in the treatment of sepsis.

Clinical trial registration

[http://www.chictr.org.cn/showprojen.aspx?proj=29851], identifier [ChiCTR1800017633].

Parenteral Vitamin C in Patients with Severe Infection: A Systematic Review

BACKGROUND: Inflammation and oxidative damage caused by severe infections may be attenuated by vitamin C. METHODS: We conducted a systematic review of randomized controlled trials (RCTs) of parenteral vitamin C as combined therapy or monotherapy versus no parenteral vitamin C administered to adults hospitalized with severe infection. The primary outcome was mortality. We performed random-effects meta-analyses and assessed certainty in effect estimates. RESULTS: Of 1547 citations, 41 RCTs (n = 4915 patients) were eligible for inclusion. Low-certainty evidence suggested that vitamin C may reduce in-hospital mortality (21 RCTs, 2762 patients; risk ratio, 0.88 [95% confidence interval (CI), 0.73 to 1.06]), 30-day mortality (24 RCTs, 3436 patients; risk ratio, 0.83 [95% CI, 0.71 to 0.98]), and early mortality (before hospital discharge or 30 days; 34 RCTs, 4366 patients; risk ratio, 0.80 [95% CI, 0.68 to 0.93]). Effects were attenuated in sensitivity analyses limited to published blinded trials at low risk-of-bias (in-hospital mortality: risk ratio, 1.07 [95% CI, 0.92 to 1.24], moderate certainty; 30-day mortality: risk ratio, 0.88 [95% CI, 0.71 to 1.10], low certainty; and early mortality: risk ratio, 0.88 [95% CI, 0.73 to 1.06], low certainty). For 90-day mortality, all trials had low risk-of-bias; moderate-certainty evidence suggested harm (five RCTs, 1722 patients; risk ratio, 1.07 [95% CI, 0.94 to 1.21]). Moderate-certainty evidence suggested an increased risk of hypoglycemia (risk ratio, 1.20 [95% CI, 0.69 to 2.08]). Effects on other secondary outcomes were mixed and informed by low-certainty evidence. No credible subgroup effects were observed for mortality related to cointerventions (monotherapy vs. combined therapy), dose, or type of infection (Covid-19 vs. other). CONCLUSIONS: Overall, evidence from RCTs does not establish a survival benefit for vitamin C in patients with severe infection. (PROSPERO number, CRD42020209187.)

Delayed Diagnosis of Severe Hypoglycemia in a Septic Patient With Chronic Renal Failure

High-dose vitamin C therapy has gained increased interest as an adjunctive treatment of septic shock, although convincing evidence is still lacking. High blood levels of vitamin C may interfere with several point-of-care blood glucose meters. We describe the case of a 67-year-old septic patient known with chronic renal failure who developed truly severe hypoglycemia, which was masked by spuriously high glucose values measured on a capillary blood glucose meter. This initially led to the treatment of spurious hyperglycemia with high-dose insulin and a delayed correct diagnosis and treatment, rendering substantial risk for the patient. Awareness of this dangerous interference is warranted.

The emerging roles of next-generation metabolomics in critical care nutrition

Critical illness leads to millions of deaths worldwide each year, with a significant surge due to the COVID-19 pandemic. Patients with critical illness are frequently associated with systemic metabolic disorders and malnutrition. The idea of intervention for critically ill patients through enteral and parenteral nutrition has been paid more and more attention gradually. However, current nutritional therapies focus on evidence-based practice, and there have been lacking holistic approaches for nutritional support assessment. Metabolomics is a well-established omics technique in system biology that enables comprehensive profiling of metabolites in a biological system and thus provides the underlying information expressed and modulated by all other omics layers. In recent years, with the development of high-resolution and accurate mass spectrometry, metabolomics entered a new "generation", promoting its broader applications in critical care nutrition. In this review, we first described the technological development and milestones of next-generation metabolomics in the past 20 years. We then discussed the emerging roles of next-generation metabolomics in advancing our understanding of critical care nutrition, such as nutritional deficiency risk evaluation, metabolic mechanisms of nutritional therapies, and novel nutrition target identification.

The effect of intravenous vitamin C on clinical outcomes in patients with sepsis or septic shock: A meta-analysis of randomized controlled trials

Objectives

Vitamin C deficiency is common among patients with sepsis and has been associated with poor clinical outcomes. Nevertheless, the effect of intravenous (IV) vitamin C for the treatment of sepsis remains controversial. The purpose of this meta-analysis was to evaluate the effect of IV vitamin C in patients with sepsis or septic shock.

Methods

Electronic databases (PubMed, Embase, Scopus, and Cochrane Library) were searched from inception through May 25, 2022 for randomized controlled trials evaluating the effect of IV vitamin C treatment in patients with sepsis. The primary outcome was short-term mortality, and secondary outcomes including the duration of vasopressor, length of intensive care unit (ICU) stay, and Sequential Organ Failure Assessment (SOFA) score after vitamin C treatment. Subgroup analyses were performed based on the type of disease, dose and duration of IV vitamin C.

Results

A total of 10 studies were included, with a total sample of 755 septic patients. The IV vitamin C was associated with a significant reduction in the short-term mortality (OR 0.51, 95% CI 0.37–0.69, I² = 0%) and duration of vasopressor (MD −27.88, 95% CI −49.84 to −5.92, I² = 95%). The length of ICU stay (MD −0.68, 95% CI −2.13 to 0.78, I² = 74%) and SOFA score (MD −0.05, 95% CI −1.69 to 1.58, I² = 86%) were not significantly different between two groups.

Conclusion

In patients with sepsis or septic shock, the IV vitamin C reduced the short-term mortality rate and duration of vasopressor, with no effect on the length of ICU stay and SOFA score. Further trials are required to explore the optimal dosage and duration of IV vitamin C.

Systematic Review Registration

https://inplasy.com/inplasy-2022-6-0013/, identifier INPLASY202260013.

Role of Oxidative Stress in the Pathogenesis of Atherothrombotic Diseases

Oxidative stress is generated by the imbalance between reactive oxygen species (ROS) formation and antioxidant scavenger system’s activity. Increased ROS, such as superoxide anion, hydrogen peroxide, hydroxyl radical and peroxynitrite, likely contribute to the development and complications of atherosclerotic cardiovascular diseases (ASCVD). In genetically modified mouse models of atherosclerosis, the overexpression of ROS-generating enzymes and uncontrolled ROS formation appear to be associated with accelerated atherosclerosis. Conversely, the overexpression of ROS scavenger systems reduces or stabilizes atherosclerotic lesions, depending on the genetic background of the mouse model. In humans, higher levels of circulating biomarkers derived from the oxidation of lipids (8-epi-prostaglandin F_2α, and malondialdehyde), as well as proteins (oxidized low-density lipoprotein, nitrotyrosine, protein carbonyls, advanced glycation end-products), are increased in conditions of high cardiovascular risk or overt ASCVD, and some oxidation biomarkers have been reported as independent predictors of ASCVD in large observational cohorts. In animal models, antioxidant supplementation with melatonin, resveratrol, Vitamin E, stevioside, acacetin and n-polyunsaturated fatty acids reduced ROS and attenuated atherosclerotic lesions. However, in humans, evidence from large, placebo-controlled, randomized trials or prospective studies failed to show any athero-protective effect of antioxidant supplementation with different compounds in different CV settings. However, the chronic consumption of diets known to be rich in antioxidant compounds (e.g., Mediterranean and high-fish diet), has shown to reduce ASCVD over decades. Future studies are needed to fill the gap between the data and targets derived from studies in animals and their pathogenetic and therapeutic significance in human ASCVD.

Opioids and Vitamin C: Known Interactions and Potential for Redox-Signaling Crosstalk

Opioids are among the most widely used classes of pharmacologically active compounds both clinically and recreationally. Beyond their analgesic efficacy via μ opioid receptor (MOR) agonism, a prominent side effect is central respiratory depression, leading to systemic hypoxia and free radical generation. Vitamin C (ascorbic acid; AA) is an essential antioxidant vitamin and is involved in the recycling of redox cofactors associated with inflammation. While AA has been shown to reduce some of the negative side effects of opioids, the underlying mechanisms have not been explored. The present review seeks to provide a signaling framework under which MOR activation and AA may interact. AA can directly quench reactive oxygen and nitrogen species induced by opioids, yet this activity alone does not sufficiently describe observations. Downstream of MOR activation, confounding effects from AA with STAT3, HIF1α, and NF-κB have the potential to block production of antioxidant proteins such as nitric oxide synthase and superoxide dismutase. Further mechanistic research is necessary to understand the underlying signaling crosstalk of MOR activation and AA in the amelioration of the negative, potentially fatal side effects of opioids.

ESPEN micronutrient guideline

BACKGROUND

Trace elements and vitamins, named together micronutrients (MNs), are essential for human metabolism. Recent research has shown the importance of MNs in common pathologies, with significant deficiencies impacting the outcome.

OBJECTIVE

This guideline aims to provide information for daily clinical nutrition practice regarding assessment of MN status, monitoring, and prescription. It proposes a consensus terminology, since many words are used imprecisely, resulting in confusion. This is particularly true for the words "deficiency", "repletion", "complement", and "supplement".

METHODS

The expert group attempted to apply the 2015 standard operating procedures (SOP) for ESPEN which focuses on disease. However, this approach could not be applied due to the multiple diseases requiring clinical nutrition resulting in one text for each MN, rather than for diseases. An extensive search of the literature was conducted in the databases Medline, PubMed, Cochrane, Google Scholar, and CINAHL. The search focused on physiological data, historical evidence (published before PubMed release in 1996), and observational and/or randomized trials. For each MN, the main functions, optimal analytical methods, impact of inflammation, potential toxicity, and provision during enteral or parenteral nutrition were addressed. The SOP wording was applied for strength of recommendations.

RESULTS

There was a limited number of interventional trials, preventing meta-analysis and leading to a low level of evidence. The recommendations underwent a consensus process, which resulted in a percentage of agreement (%): strong consensus required of >90% of votes. Altogether the guideline proposes sets of recommendations for 26 MNs, resulting in 170 single recommendations. Critical MNs were identified with deficiencies being present in numerous acute and chronic diseases. Monitoring and management strategies are proposed.

CONCLUSION

This guideline should enable addressing suboptimal and deficient status of a bundle of MNs in at-risk diseases. In particular, it offers practical advice on MN provision and monitoring during nutritional support.

Mitochondrial Pathophysiology on Chronic Kidney Disease

In healthy kidneys, interstitial fibroblasts are responsible for the maintenance of renal architecture. Progressive interstitial fibrosis is thought to be a common pathway for chronic kidney diseases (CKD). Diabetes is one of the boosters of CKD. There is no effective treatment to improve kidney function in CKD patients. The kidney is a highly demanding organ, rich in redox reactions occurring in mitochondria, making it particularly vulnerable to oxidative stress (OS). A dysregulation in OS leads to an impairment of the Electron transport chain (ETC). Gene deficiencies in the ETC are closely related to the development of kidney disease, providing evidence that mitochondria integrity is a key player in the early detection of CKD. The development of novel CKD therapies is needed since current methods of treatment are ineffective. Antioxidant targeted therapies and metabolic approaches revealed promising results to delay the progression of some markers associated with kidney disease. Herein, we discuss the role and possible origin of fibroblasts and the possible potentiators of CKD. We will focus on the important features of mitochondria in renal cell function and discuss their role in kidney disease progression. We also discuss the potential of antioxidants and pharmacologic agents to delay kidney disease progression.

The Potential Role of Intravenous Vitamin C Monotherapy in Critical Illness

Vitamin C is an essential micronutrient with antioxidant properties and its use in critical illness has gained interest in recent years.¹ Four systematic reviews/meta-analyses (SRMAs) have been published in 2021 alone (see Table 1 summary).^2-5 These 4 SRMAs included between 8-43 randomized controlled trials evaluating vitamin C with or without thiamine and/or corticosteroids in general ICU patients and those with sepsis and septic shock. ^2-5 Fujii et al performed a network meta-analysis which is a method for comparing multiple treatments using both direct and indirect evidence across trials that included studies with vitamin C monotherapy or with thiamine and/or corticosteroids.⁹ This article is protected by copyright. All rights reserved.