Randomized, prospective trial of antioxidant supplementation in critically ill surgical patients

Reconstitution fluid type does not affect pulmonary inflammation or DNA damage following infusion of lyophilized plasma

BACKGROUND

Dysfunctional inflammation following traumatic hemorrhage can lead to multiple-organ failure and death. In our polytrauma swine model, lyophilized plasma (LP) reconstituted with sterile water and ascorbic acid suppressed systemic inflammation and attenuated DNA damage. However, it remains unknown whether the inflammatory response is affected by the type of fluid used to reconstitute LP. We hypothesized that common resuscitation fluids such as normal saline (LP-NS), lactated Ringer's solution (LP-LR), Hextend (LP-HX), or sterile water (LP-SW) would yield similar inflammation profiles and DNA damage following LP reconstitution and transfusion.

METHODS

This was a randomized, prospective, blinded animal study. LP was reconstituted to 50% of original volume with NS, LR, HX, or SW buffered with 15-mM ascorbic acid. Forty swine were subjected to a validated model of polytrauma, hemorrhagic shock, and Grade V liver injury and resuscitated with LP. Serum interleukin 6 (IL-6), IL-10, plasma C-reactive protein, and 8-hydroxy-2-deoxyguanosine concentrations were assessed for systemic inflammation and DNA damage at baseline, 2 hours, and 4 hours following liver injury. Lung inflammation was evaluated by Real Time Polymerize Chain Reaction (RT-PCR).

RESULTS

Reconstituted LP pH was similar between groups before resuscitation. IL-6 and IL-10 increased at 2 hours and 4 hours compared with baseline in all groups (p < 0.017). DNA damage increased at 2 hours and 4 hours compared with baseline and from 2 hours to 4 hours in the LP-NS, LP-LR, and LP-SW groups (all p < 0.017). Animals resuscitated with LP-HX not only demonstrated increased DNA damage at 4 hours versus baseline but also had the lowest C-reactive protein level at 2 hours and 4-hours (p < 0.017). Overall, differences between groups were similar for DNA damage and lung inflammation.

CONCLUSION

Reconstitution fluid type does not affect inflammatory cytokine profiles or DNA damage following LP transfusion in this swine polytrauma model. Based on universal availability, these data suggest that sterile water is the most logical choice for LP reconstitution in humans.

LEVEL OF EVIDENCE

Prognostic, level II.

Vitamin C supplementation in the critically ill patient

PURPOSE OF REVIEW

Vitamin C is not only an essential nutrient involved in many anabolic pathways, but also an important player of the endogenous antioxidant defense. Low plasma levels are very common in critical care patients and may reflect severe deficiency states.

RECENT FINDINGS

Vitamin C scavenges reactive oxygen species such as superoxide and peroxynitrite in plasma and cells (preventing damage to proteins, lipids and DNA), prevents occludin dephosphorylation and loosening of the tight junctions. Ascorbate improves microcirculatory flow impairment by inhibiting tumor-necrosis-factor-induced intracellular adhesion molecule expression, which triggers leukocyte stickiness and slugging. Clinical trials in sepsis, trauma and major burns testing high-dose vitamin C show clinical benefit. Restoration of normal plasma levels in inflammatory patients requires the administration of 3 g/day for several days, which is 30 times the daily recommended dose.

SUMMARY

The recent research on the modulation of oxidative stress and endothelial protection offer interesting therapeutic perspectives, based on the biochemical evidence, with limited or even absent side-effects.

Impact of vitamin C supplementation on post-cardiac surgery ICU and hospital length of stay

BACKGROUND

Prolonged intensive care unit (ICU) and hospital stay after cardiac surgery is vitally important and is influenced by both intraoperative and postoperative factors.

OBJECTIVES

This randomized clinical trial study was designed to assess whether vitamin C supplementation could reduce the length of ICU and hospital stay in post-cardiac surgery patients.

PATIENTS AND METHODS

Two hundred and ninety patients scheduled for adult cardiac surgery including coronary, valve and congenital operations were randomized into two groups: an intervention group, who received 2 g of vitamin C (ascorbic acid) intravenously, immediately before surgery in the operating theatre, followed by 1 g daily oral doses for the first 4 postoperative days; and a placebo group, who received an equal number of identical tablets in the same shape and size.

RESULTS

Hospital length of stay was significantly different between the two groups (10.17 ± 4.63 days in the intervention group vs. 12 ± 4.51 days in the placebo group; P = 0.01), while there was no significant difference in the ICU stay between the groups (3.42 ± 1.06 days in intervention group vs. 3.43 ± 1.09 days in the placebo group; P = 0.88). There were significant differences in the intubation time and the drainage volume in the ICU and the first 24 postoperative hours between the two groups (P for both = 0.003).

CONCLUSIONS

Vitamin C can decrease the length of hospital stay, drainage volume in the ICU and in the first 24 postoperative hours, intubation time and some complications in patients after cardiac surgery; perhaps by decreasing inflammatory factors.

Emerging drugs for acute lung injury

INTRODUCTION

Acute respiratory distress syndromes (ARDS) are devastating disorders of overwhelming pulmonary inflammation and hypoxemia, resulting in high morbidity and mortality.

AREAS COVERED

The main pharmacological treatment strategies have focused on the attempted inhibition of excessive inflammation or the manipulation of the resulting physiological derangement causing respiratory failure. Additionally, such interventions may allow reduced occurence mechanical ventilation injury. Despite promising preclinical and small clinical studies, almost all therapies have been shown to be unsuccessful in large-scale randomized controlled trials. The evidence for pharmacological treatment for ARDS is reviewed. Potential future treatments are also presented.

EXPERT OPINION

We suggest for future clinical trials addressing prevention and early intervention to attenuate lung injury and progression to respiratory failure.

Redox Changes Induced by General Anesthesia in Critically Ill Patients with Multiple Traumas

The critically ill polytrauma patient is a constant challenge for the trauma team due to the complexity of the complications presented. Intense inflammatory response and infections, as well as multiple organ dysfunctions, significantly increase the rate of morbidity and mortality in these patients. Moreover, due to the physiological and biochemical imbalances present in this type of patients, the bioproduction of free radicals is significantly accelerated, thus installing the oxidative stress. In the therapeutic management of such patients, multiple surgical interventions are required and therefore they are being subjected to repeated general anesthesia. In this paper, we want to present the pathophysiological implications of oxidative stress in critically ill patients with multiple traumas and the implications of general anesthesia on the redox mechanisms of the cell. We also want to summarize the antioxidant treatments able to reduce the intensity of oxidative stress by modulating the biochemical activity of some cellular mechanisms.

Micronutrients after burn injury: a review

Supplementation of micronutrients after burn injury is common practice in order to fight oxidative stress, support the immune system, and optimize wound healing. Assessing micronutrient status after burn injury is difficult because of hemodilution in the resuscitation phase, redistribution of nutrients from the serum to other organs, and decreases in carrier proteins such as albumin. Although there are many preclinical data, there are limited studies in burn patients. Promising research is being conducted on combinations of micronutrients, especially via the intravenous route.

Prospective Randomized Trial on Postoperative Administration of Diet Containing Eicosapentaenoic Acid, Docosahexaenoic Acid, Gamma-linolenic Acid, and Antioxidants in Head and Neck Cancer Surgery Patients with Free-flap Reconstruction

OBJECTIVES

The purpose of this prospective, randomized study was to evaluate the effects of a diet containing eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), gamma-linolenic acid (GLA), and antioxidants in head and neck cancer surgery patients with free-flap reconstruction.

METHODS

In this randomized, prospective study, 62 patients with head and neck cancers were assigned to receive a general control diet (Ensure^® H; Abbott Japan, Tokyo, Japan) or the study diet (Oxepa^®; Abbott Japan) containing EPA, DHA, GLA, and antioxidants (eg vitamins A, E, and C). The primary assessment item was the degree of postoperative inflammation, as assessed by measuring maximum body temperature and levels of C-reactive protein (CRP) and procalcitonin from the day of surgery to postoperative day 8. Secondary assessment items were lengths of stays in the intensive care unit (ICU) and hospital.

RESULTS

The control diet group (n = 32) and study diet group (n = 30) showed no significant difference in energy administered through diet. No significant differences in the parameters of the primary assessment item were noted. Length of stay in the ICU was significantly shorter for the control diet group than for the study diet group (P = 0.011). No significant difference in duration of hospitalization was seen between groups.

CONCLUSION

No usefulness of a diet containing EPA, DHA, GLA, and antioxidants was demonstrated.

Vitamin C revisited

This narrative review summarizes the role of vitamin C in mitigating oxidative injury-induced microcirculatory impairment and associated organ failure in ischemia/reperfusion or sepsis. Preclinical studies show that high-dose vitamin C can prevent or restore microcirculatory flow impairment by inhibiting activation of nicotinamide adenine dinucleotide phosphate-oxidase and inducible nitric oxide synthase, augmenting tetrahydrobiopterin, preventing uncoupling of oxidative phosphorylation, and decreasing the formation of superoxide and peroxynitrite, and by directly scavenging superoxide. Vitamin C can additionally restore vascular responsiveness to vasoconstrictors, preserve endothelial barrier by maintaining cyclic guanylate phosphatase and occludin phosphorylation and preventing apoptosis. Finally, high-dose vitamin C can augment antibacterial defense. These protective effects against overwhelming oxidative stress due to ischemia/reperfusion, sepsis or burn seems to mitigate organ injury and dysfunction, and promote recovery after cardiac revascularization and in critically ill patients, in the latter partially in combination with other antioxidants. Of note, several questions remain to be solved, including optimal dose, timing and combination of vitamin C with other antioxidants. The combination obviously offers a synergistic effect and seems reasonable during sustained critical illness. High-dose vitamin C, however, provides a cheap, strong and multifaceted antioxidant, especially robust for resuscitation of the circulation. Vitamin C given as early as possible after the injurious event, or before if feasible, seems most effective. The latter could be considered at the start of cardiac surgery, organ transplant or major gastrointestinal surgery. Preoperative supplementation should consider the inhibiting effect of vitamin C on ischemic preconditioning. In critically ill patients, future research should focus on the use of short-term high-dose intravenous vitamin C as a resuscitation drug, to intervene as early as possible in the oxidant cascade in order to optimize macrocirculation and microcirculation and limit cellular injury.

Modern resuscitation of hemorrhagic shock: what is on the horizon?

PURPOSE

Mortality rates among the severely injured remain high. The successful treatment of hemorrhagic shock relies on expeditious control of bleeding through surgical ligation, packing, or endovascular techniques. An important secondary concern in hemorrhaging patients is how to respond to the lost blood volume. A single method that is able to adequately address all needs of the exsanguinating patient has not yet been agreed upon, despite a large growth of knowledge regarding the causative factors of traumatic shock.

METHODS

A review of relevent literature was performed.

CONCLUSIONS

Many different trials are currently underway to discriminate ways to improve outcomes in the severely injured and bleeding patient.  This paper will review: (1) recent advances in our understanding of the effects hemorrhagic shock has on the coagulation cascade and vascular endothelium, (2) recent research findings that have changed resuscitation, and (3) resuscitation strategies that are not widely used but under active investigation.

Intravenous ascorbic acid as an adjuvant to interleukin-2 immunotherapy

Interleukin-2 (IL-2) therapy has been demonstrated to induce responses in 10-20% of advanced melanoma and renal cell carcinoma patients, which translates into durable remissions in up to half of the responsers. Unfortunately the use of IL-2 has been associated with severe toxicity and death. It has been previously observed and reported that IL-2 therapy causes a major drop in circulating levels of ascorbic acid (AA). The IL-2 induced toxicity shares many features with sepsis such as capillary leakage, systemic complement activation, and a relatively non-specific rise in inflammatory mediators such as TNF-alpha, C-reactive protein, and in advanced cases organ failure. Animal models and clinical studies have shown rapid depletion of AA in conditions of sepsis and amelioration associated with administration of AA (JTM 9:1-7, 2011). In contrast to other approaches to dealing with IL-2 toxicity, which may also interfere with therapeutic effects, AA possesses the added advantage of having direct antitumor activity through cytotoxic mechanisms and suppression of angiogenesis. Here we present a scientific rationale to support the assessment of intravenous AA as an adjuvant to decrease IL-2 mediated toxicity and possibly increase treatment efficacy.

Investigation into the role of Cu/Zn-SOD delivery system on its antioxidant and antiinflammatory activity in rat model of peritonitis

BACKGROUND

The current study evaluated the role of delivery system (solution, conventional liposomes and PEG-ylated liposomes) on superoxide dismutase (SOD) antioxidant and antiinflammatory properties in a rat model of lipopolysaccharide (LPS)-induced peritonitis.

METHODS

Fifty male albino rats (Wistar-Bratislava) were divided into five groups (n=10). Control group received saline and the other four groups received intraperitoneal injections of LPS (5mg/kg). Among the LPS-injected groups, one was LPS control group and the other three groups received the endotoxin injection 30min after receiving the same dose of SOD (500U/kg, ip) in different delivery systems: saline solution (SOD-S), conventional liposomes (SOD-L) or PEG-ylated liposomes (SOD-PL). The animals were euthanized 6h after LPS injection, blood samples were collected and acute phase response (total and differential leukocytes count; tumor necrosis factor α), antioxidants (total antioxidants; reduced glutathione), oxidative stress (total oxidants; lipid peroxidation) and nitrosative stress (nitric oxide metabolites; nitrotyrosine) were evaluated.

RESULTS

Intraperitoneal administration of LPS to rats induced a marked inflammatory and oxidative response in plasma. On the other hand, all SOD formulations had protective effect against endotoxin-induced inflammation and oxidative/nitrosative stress, but PEG-ylated liposomes had the most significant activity. Thus, SOD-PL administration significantly reduced the effects of LPS on bone marrow acute phase response, the oxidative status and production of nitric oxide metabolites, while increasing the markers of antioxidant response in a significant manner.

CONCLUSION

SOD supplementation interferes both with inflammatory and oxidative pathways involved in LPS-induced acute inflammation, PEG-ylated liposomal formulation being of choice among the tested delivery systems.

Phase I safety trial of intravenous ascorbic acid in patients with severe sepsis

Background

Parenterally administered ascorbic acid modulates sepsis-induced inflammation and coagulation in experimental animal models. The objective of this randomized, double-blind, placebo-controlled, phase I trial was to determine the safety of intravenously infused ascorbic acid in patients with severe sepsis.

Methods

Twenty-four patients with severe sepsis in the medical intensive care unit were randomized 1:1:1 to receive intravenous infusions every six hours for four days of ascorbic acid: Lo-AscA (50 mg/kg/24 h, n = 8), or Hi-AscA (200 mg/kg/24 h, n = 8), or Placebo (5% dextrose/water, n = 8). The primary end points were ascorbic acid safety and tolerability, assessed as treatment-related adverse-event frequency and severity. Patients were monitored for worsened arterial hypotension, tachycardia, hypernatremia, and nausea or vomiting. In addition Sequential Organ Failure Assessment (SOFA) scores and plasma levels of ascorbic acid, C-reactive protein, procalcitonin, and thrombomodulin were monitored.

Results

Mean plasma ascorbic acid levels at entry for the entire cohort were 17.9 ± 2.4 μM (normal range 50-70 μM). Ascorbic acid infusion rapidly and significantly increased plasma ascorbic acid levels. No adverse safety events were observed in ascorbic acid-infused patients. Patients receiving ascorbic acid exhibited prompt reductions in SOFA scores while placebo patients exhibited no such reduction. Ascorbic acid significantly reduced the proinflammatory biomarkers C-reactive protein and procalcitonin. Unlike placebo patients, thrombomodulin in ascorbic acid infused patients exhibited no significant rise, suggesting attenuation of vascular endothelial injury.

Conclusions

Intravenous ascorbic acid infusion was safe and well tolerated in this study and may positively impact the extent of multiple organ failure and biomarkers of inflammation and endothelial injury.

Trial registration

ClinicalTrials.gov identifier NCT01434121.

Oxidants in Acute and Chronic Lung Disease

Oxidants play an important role in homeostatic function, but excessive oxidant generation has an adverse effect on health. The manipulation of Reactive Oxygen Species (ROS) can have a beneficial effect on various lung pathologies. However indiscriminate uses of anti-oxidant strategies have not demonstrated any consistent benefit and may be harmful. Here we propose that nuanced strategies are needed to modulate the oxidant system to obtain a beneficial result in the lung diseases such as Acute Lung Injury (ALI) and Chronic Obstructive Pulmonary Disease (COPD). We identify novel areas of lung oxidant responses that may yield fruitful therapies in the future.

Early Enteral Nutrition for Burn Injury

Significance: Nutrition has been recognized as a critical component of acute burn care and ultimate wound healing. Debate remains over the appropriate timing of enteral nutrition and the benefit of supplemental trace elements, antioxidants, and immunonutrition for critically ill burn patients. Pharmacotherapy to blunt the metabolic response to burn injury plays a critical role in effective nutritional support. Recent Advances: Further evidence is demonstrating long-term benefits from pharmacologic immunomodulation given the prolonged metabolic response to injury that may last for over a year following the initial insult. Critical Issues: The majority of evidence regarding early enteral feeding comes from mixed populations and smaller studies. However, on balance, available evidence favors early feeding. Data regarding immunonutrition does not support the routine use of these products. Limited data regarding use of antioxidants and trace elements support their use. Future Directions: Further evaluation of anti-inflammatory mediators of the immune response, such as statins, will likely play a role in the future. Further data are needed on the dosing and route of micronutrients as well as the utility of immunonutrition. Finally, little is known about nutrition in the obese burn patient making this an important area for investigation.

Oxidants and redox signaling in acute lung injury

Acute lung injury (ALI) and its more severe form of clinical manifestation, the acute respiratory distress syndrome is associated with significant dysfunction in air exchange due to inflammation of the lung parenchyma. Several factors contribute to the inflammatory process, including hypoxia (inadequate oxygen), hyperoxia (higher than normal partial pressure of oxygen), inflammatory mediators (such as cytokines), infections (viral and bacterial), and environmental conditions (such as cigarette smoke or noxious gases). However, studies over the past several decades suggest that oxidants formed in the various cells of the lung including endothelial, alveolar, and epithelial cells as well as lung macrophages and neutrophils in response to the factors mentioned above mediate the pathogenesis of ALI. Oxidants modify cellular proteins, lipids, carbohydrates, and DNA to cause their aberrant function. For example, oxidation of lipids changes membrane permeability. Interestingly, recent studies also suggest that spatially and temporally regulated production of oxidants plays an important role antimicrobial defense and immunomodulatory function (such as transcription factor activation). To counteract the oxidants an arsenal of antioxidants exists in the lung to maintain the redox status, but when overwhelmed tissue injury and exacerbation of inflammation occurs. We present below the current understanding of the pathogenesis of oxidant-mediated ALI.

Evaluation of vitamin C for adjuvant sepsis therapy

SIGNIFICANCE

Evidence is emerging that parenteral administration of high-dose vitamin C may warrant development as an adjuvant therapy for patients with sepsis.

RECENT ADVANCES

Sepsis increases risk of death and disability, but its treatment consists only of supportive therapies because no specific therapy is available. The characteristics of severe sepsis include ascorbate (reduced vitamin C) depletion, excessive protein nitration in microvascular endothelial cells, and microvascular dysfunction composed of refractive vasodilation, endothelial barrier dysfunction, and disseminated intravascular coagulation. Parenteral administration of ascorbate prevents or even reverses these pathological changes and thereby decreases hypotension, edema, multiorgan failure, and death in animal models of sepsis.

CRITICAL ISSUES

Dehydroascorbic acid appears to be as effective as ascorbate for protection against microvascular dysfunction, organ failure, and death when injected in sepsis models, but information about pharmacodynamics and safety in human subjects is only available for ascorbate. Although the plasma ascorbate concentration in critically ill and septic patients is normalized by repletion protocols that use high doses of parenteral ascorbate, and such doses are tolerated well by most healthy subjects, whether such large amounts of the vitamin trigger adverse effects in patients is uncertain.

FUTURE DIRECTIONS

Further study of sepsis models may determine if high concentrations of ascorbate in interstitial fluid have pro-oxidant and bacteriostatic actions that also modify disease progression. However, the ascorbate depletion observed in septic patients receiving standard care and the therapeutic mechanisms established in models are sufficient evidence to support clinical trials of parenteral ascorbate as an adjuvant therapy for sepsis.

Vitamin C for preventing and treating tetanus

BACKGROUND

Tetanus is a severe disease that can be prevented by vaccination. In developing countries vaccination coverage is not always high. Cases still occur also in developed countries, particularly in elderly people owing to their reduced immuno protection. There are about 1 million tetanus cases per year globally. In animal studies, vitamin C has protected against various infections and bacterial toxins. In a study with rats, vitamin C protected against the purified tetanus toxin.

OBJECTIVES

To assess the prophylactic and therapeutic effect of vitamin C on tetanus.

SEARCH METHODS

In May 2013 we searched the Cochrane Wounds Group Specialised Register; The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library); Ovid MEDLINE; Ovid MEDLINE (In-Process & Other Non-Indexed Citations ); and Ovid EMBASE for this third update.

SELECTION CRITERIA

Controlled trials of vitamin C as a prevention or treatment for tetanus, whether or not these were placebo controlled, in any language, published or unpublished. Two review authors independently made inclusion decisions.

DATA COLLECTION AND ANALYSIS

Both review authors independently extracted data from trial reports and assessed methodological quality. Since one of the cells in a 2 × 2 table had no events, we calculated the odds ratio (OR) and its 95% confidence interval (CI) for case fatality rate by using the Peto-method. Another of the 2 × 2 tables had no empty cells and the inverse-variance method was used to calculate its risk ratio (RR) estimate and 95% CI. We also used the Fisher's exact test to calculate the exact 95% CI for the OR of the 2 × 2 table with the empty cell.

MAIN RESULTS

One single trial was eligible for inclusion. This non-randomised, unblinded, controlled trial undertaken in Bangladesh involved 117 tetanus patients. Vitamin C at a dosage of 1 g/day was administered intravenously alongside conventional treatment. At recruitment, the participants were stratified into two age groups and the results were reported by age. There was a significant difference in the vitamin C effect between the two age groups (P = 0.01). In the tetanus patients aged 1 to 12 years (n = 62), vitamin C treatment was associated with a 100% reduction in case fatality rate (95% CI from -100% to -94%). In patients aged 13 to 30 years (n = 55), vitamin C treatment was associated with a 45% reduction in case fatality rate (95% CI from -69% to -5%).

AUTHORS' CONCLUSIONS

A single, non-randomised, poorly reported trial of vitamin C as a treatment for tetanus suggests a considerable reduction in mortality. However, concerns about trial quality mean that this result must be interpreted with caution and vitamin C cannot be recommended as a treatment for tetanus on the basis of this evidence. New trials should be carried out to examine the effect of vitamin C on tetanus treatment.

Massive and long-lasting decrease in vitamin C plasma levels as a consequence of extracorporeal circulation

OBJECTIVE

The use of cardiopulmonary bypass (CPB) is suggested to induce oxidative stress, reflected by an imbalance between prooxidant and antioxidant substances. The majority of studies published have either focused on only one aspect (prooxidant or antioxidant side) or covered only a short observation period. Therefore, the aim of this study was to investigate the long-term effects of CPB on the balance of prooxidative markers and antioxidant substances in one single group of patients, being able to estimate the degree of oxidative stress.

METHODS

Blood samples were taken from 29 patients undergoing cardiovascular surgery beginning the day before surgery through postoperative day 6 (discharge). Plasma concentrations of vitamins C (total ascorbic acid) and E and malondialdehyde were measured by high-performance liquid chromatography. Plasma levels of ascorbyl free radical were determined using electron paramagnetic resonance spectroscopy.

RESULTS

The study showed a significant decrease in vitamin C plasma levels during CPB without any recovery of vitamin C up to the time of discharge. Furthermore, CPB induced a significant increase in malondialdehyde plasma concentrations immediately after unclamping, accompanied by a significant increase in the ascorbyl free radical to total ascorbic acid ratio. The latter stayed elevated until the end of observation.

CONCLUSIONS

Our findings indicate that the oxidative stress event after CPB can be divided into two phases: Immediately after reperfusion, a massive oxidative stress occurs, reflected by the increase in malondialdehyde. During convalescence, there must be an ongoing situation of oxidative stress, especially in the water-soluble compartment, leading to the consumption of vitamin C. Because the main antioxidant substance, vitamin C, did not increase again over the entire observation period, supplementation should be given consideration.

Vitamin C for preventing and treating pneumonia

BACKGROUND

Pneumonia is one of the most common serious infections, causing two million deaths annually among young children in low-income countries. In high-income countries pneumonia is most significantly a problem of the elderly.

OBJECTIVES

To assess the prophylactic and therapeutic effects of vitamin C on pneumonia.

SEARCH METHODS

We searched CENTRAL 2013, Issue 3, MEDLINE (1950 to March week 4, 2013), EMBASE (1974 to April 2013) and Web of Science (1955 to April 2013).

SELECTION CRITERIA

To assess the therapeutic effects of vitamin C, we selected placebo-controlled trials. To assess prophylactic effects, we selected controlled trials with or without a placebo.

DATA COLLECTION AND ANALYSIS

Two review authors independently read the trial reports and extracted data.

MAIN RESULTS

We identified three prophylactic trials which recorded 37 cases of community-acquired pneumonia in 2335 people. Only one was satisfactorily randomised, double-blind and placebo-controlled. Two trials examined military recruits and the third studied boys from "lower wage-earning classes" attending a boarding school in the UK during World War II. Each of these three trials found a statistically significant (80% or greater) reduction in pneumonia incidence in the vitamin C group. We identified two therapeutic trials involving 197 community-acquired pneumonia patients. Only one was satisfactorily randomised, double-blind and placebo-controlled. That trial studied elderly patients in the UK and found lower mortality and reduced severity in the vitamin C group; however, the benefit was restricted to the most ill patients. The other therapeutic trial studied adults with a wide age range in the former Soviet Union and found a dose-dependent reduction in the duration of pneumonia with two vitamin C doses. We identified one prophylactic trial recording 13 cases of hospital-acquired pneumonia in 37 severely burned patients; one-day administration of vitamin C had no effect on pneumonia incidence. The identified studies are clinically heterogeneous which limits their comparability. The included studies did not find adverse effects of vitamin C.

AUTHORS' CONCLUSIONS

The prophylactic use of vitamin C to prevent pneumonia should be further investigated in populations who have a high incidence of pneumonia, especially if dietary vitamin C intake is low. Similarly, the therapeutic effects of vitamin C should be studied, especially in patients with low plasma vitamin C levels. The current evidence is too weak to advocate prophylactic use of vitamin C to prevent pneumonia in the general population. Nevertheless, therapeutic vitamin C supplementation may be reasonable for pneumonia patients who have low vitamin C plasma levels because its cost and risks are low.

Targeting oxidative stress response by green tea polyphenols: clinical implications

Green tea polyphenols, the most interesting constituent of green tea leaves, have been shown to have both pro-oxidant and antioxidant properties. Both pro-oxidant and antioxidant properties are expected to contribute to modulation of oxidative stress response under ideal optimal dosage regimens. Exposure to a low concentration of a pro-oxidant prior to exposure to oxidative stress induces the expression of genes that code for proteins that induce adaptation in a subsequent oxidative stress. On the other hand, exposure to an antioxidant concurrently with exposure to the oxidative stress affords protection through free radical scavenging or through other indirect antioxidant mechanisms. In any case, the optimal conditions that afford protection from oxidative stress should be defined for any substance with redox properties. Green tea polyphenols, being naturally occurring substances, seem to be an ideal option for the modulation of oxidative stress response. This paper reviews available data on the pro-oxidant and antioxidant properties of green tea polyphenols focusing on their potential on the modulation of oxidative stress response.

The LPS-induced increase in circulating microparticles is not affected by vitamin C in humans

OBJECTIVE

Microparticles (MP) are considered to promote coagulation. This study aimed to characterize the time course of MP levels and the effect of high-dose vitamin C on MP formation during inflammation in an in vivo Escherichia coli endotoxin (LPS) model.

METHODS

Microparticle formation was studied in 14 male subjects in a cross-over trial who received either intravenous vitamin C at 320 mg/kg body weight (BW) or 480 mg/kg BW or saline solution in a random order on alternate trial days 3 h after intravenous exposure to LPS (2 ng/kg BW). Venous blood samples were taken before, 3 and 6 h after LPS. D-dimer, leucocyte count, C-reactive protein, plasma vitamin C and body temperature were assessed as inflammatory parameters. MP were detected using flow cytometric analysis and expressed in 10³ MP/mL plasma.

RESULTS

Microparticles levels were decreased from baseline 848 units [range 431-1705] by 21% to 671 units [253-1586] at 3 h and increased by 32% to 1119 units [288-4443] at 6 h after LPS. This pattern was not influenced by administration of vitamin C, with a change from 730 units [399-1396] at baseline by an increase to 832 units [215-2168] at 3 h to 1055 units [350-4858] at 6 h. MP subpopulations followed similar dynamics. Alterations in inflammatory parameters were independent from vitamin C administration during endotoxemia.

CONCLUSION

Microparticles are increased in acute systemic inflammation with inconsistent changes in MP subgroups in healthy subjects. Systemic vitamin C administration does not mitigate MP formation and D-dimer levels during acute systemic inflammation, suggesting that MP-induced coagulation activity is not affected by vitamin C.

Mechanical ventilation, diaphragm weakness and weaning: a rehabilitation perspective

Most patients are easily liberated from mechanical ventilation (MV) following resolution of respiratory failure and a successful trial of spontaneous breathing, but about 25% of patients experience difficult weaning. MV use leads to cellular changes and weakness, which has been linked to weaning difficulties and has been labeled ventilator induced diaphragm dysfunction (VIDD). Aggravating factors in human studies with prolonged weaning include malnutrition, chronic electrolyte abnormalities, hyperglycemia, excessive resistive and elastic loads, corticosteroids, muscle relaxant exposure, sepsis and compromised cardiac function. Numerous animal studies have investigated the effects of MV on diaphragm function. Virtually all these studies have concluded that MV use rapidly leads to VIDD and have identified cellular and molecular mechanisms of VIDD. Molecular and functional studies on the effects of MV on the human diaphragm have largely confirmed the animal results and identified potential treatment strategies. Only recently potential VIDD treatments have been tested in humans, including pharmacologic interventions and diaphragm "training". A limited number of human studies have found that specific diaphragm training can increase respiratory muscle strength in FTW patients and facilitate weaning, but larger, multicenter trials are needed.

Correlation of the oxygen radical activity and antioxidants and severity in critically ill surgical patients - study protocol

Background

Surgical patients who require an emergent operation commonly have severe sepsis or septic shock, followed by high morbidity and mortality rates.

Despite advances in treatment however, no predictable markers are available. In severe sepsis, many pathophysiologic mechanisms are involved in progression to organ failure, and oxygen free radical and antioxidants are known to contribute to this process. Oxygen free radical and antioxidants contribute to progression of organ failure in severe sepsis. In fact, oxygen radical activity has been reported to be correlated with disease severity and prognosis in patients with severe sepsis or septic shock. Accordingly, we aim to assess the usefulness of oxygen free radical and antioxidant concentrations to predict the disease severity and mortality in a cohort of critically ill surgical patients.

Methods/Design

This is a prospective observation study including patient demographic characteristics, clinical information, blood sampling/serum oxygen radical activity, serum antioxidant activity, serum antioxidant concentrations (zinc, selenium and glutamate), disease severity scores, outcomes, lengths of stay in intensive care unit, hospital 30-day mortality.

Effect of N-acetylcysteine supplementation on intracellular glutathione, urine isoprostanes, clinical score, and survival in hospitalized ill dogs

BACKGROUND

Antioxidant depletion and lipid peroxidation have been correlated with disease severity and associated with poor outcomes.

HYPOTHESIS/OBJECTIVES

Supplementing dogs with N-acetylcysteine (NAC) during the first 48 hours of hospitalization will increase cysteine, normalize glutathione concentrations, and decrease the degree of lipid peroxidation associated with illness.

ANIMALS

Sixty systemically ill hospitalized client-owned dogs and 14 healthy control dogs.

METHODS

Randomized investigator-blinded, placebo-controlled prospective study. Dogs were randomized to treatment with NAC (n = 30) versus placebo (n = 30). Antioxidants, urine 8-isoprostane/creatinine (IP/Cr), and clinical score were determined before and after treatment with NAC. Glutathione, cysteine, and vitamin E concentrations were quantified using high-performance liquid chromatography. Atomic absorption spectroscopy and enzyme-linked immunosorbent assays were used to quantify selenium and isoprostane concentrations, respectively.

RESULTS

Ill dogs had significantly lower vitamin E concentrations (27 versus 55 μg/mL; P = .0005) as well as elevated IP/Cr ratios (872 versus 399 pg/mg; P = .0007) versus healthy dogs. NAC supplementation significantly increased plasma cysteine (8.67 versus 15.1 μM; P < .0001) while maintaining glutathione concentrations. Dogs in the placebo group experienced a statistically significant decrease in glutathione concentrations (1.49 versus 1.44 mM; P = .0463). Illness severity and survival were unchanged after short duration NAC supplementation.

CONCLUSIONS

Ill dogs experience systemic oxidative stress. Supplementation with NAC during the first 48 hours of hospitalization stabilized erythrocyte glutathione concentrations. The clinical impact of this supplementation and glutathione concentration stabilization was undetermined.

Antioxidant micronutrients in the critically ill: a systematic review and meta-analysis

INTRODUCTION

Critical illness is characterized by oxidative stress, which is a major promoter of systemic inflammation and organ failure due to excessive free radical production, depletion of antioxidant defenses, or both. We hypothesized that exogenous supplementation of trace elements and vitamins could restore antioxidant status, improving clinical outcomes.

METHODS

We searched computerized databases, reference lists of pertinent articles and personal files from 1980 to 2011. We included randomized controlled trials (RCTs) conducted in critically ill adult patients that evaluated relevant clinical outcomes with antioxidant micronutrients (vitamins and trace elements) supplementation versus placebo.

RESULTS

A total of 21 RCTs met inclusion criteria. When the results of these studies were statistically aggregated (n = 20), combined antioxidants were associated with a significant reduction in mortality (risk ratio (RR) = 0.82, 95% confidence interval (CI) 0.72 to 0.93, P = 0.002); a significant reduction in duration of mechanical ventilation (weighed mean difference in days = -0.67, 95% CI -1.22 to -0.13, P = 0.02); a trend towards a reduction in infections (RR= 0.88, 95% CI 0.76 to 1.02, P = 0.08); and no overall effect on ICU or hospital length of stay (LOS). Furthermore, antioxidants were associated with a significant reduction in overall mortality among patients with higher risk of death (>10% mortality in control group) (RR 0.79, 95% CI 0.68 to 0.92, P = 0.003) whereas there was no significant effect observed for trials of patients with a lower mortality in the control group (RR = 1.14, 95% 0.72 to 1.82, P = 0.57). Trials using more than 500 μg per day of selenium showed a trend towards a lower mortality (RR = 0.80, 95% CI 0.63 to 1.02, P = 0.07) whereas trials using doses lower than 500 μg had no effect on mortality (RR 0.94, 95% CI 0.67 to 1.33, P = 0.75).

CONCLUSIONS

Supplementation with high dose trace elements and vitamins may improve outcomes of critically ill patients, particularly those at high risk of death.

Haemorrhage control in severely injured patients

Most surgeons have adopted damage control surgery for severely injured patients, in which the initial operation is abbreviated after control of bleeding and contamination to allow ongoing resuscitation in the intensive-care unit. Developments in early resuscitation that emphasise rapid control of bleeding, restrictive volume replacement, and prevention or early management of coagulopathy are making definitive surgery during the first operation possible for many patients. Improved topical haemostatic agents and interventional radiology are becoming increasingly useful adjuncts to surgical control of bleeding. Better understanding of trauma-induced coagulopathy is paving the way for the replacement of blind, unguided protocols for blood component therapy with systemic treatments targeting specific deficiencies in coagulation. Similarly, treatments targeting dysregulated inflammatory responses to severe injury are under investigation. As point-of-care diagnostics become more suited to emergency environments, timely targeted intervention for haemorrhage control will result in better patient outcomes and reduced demand for blood products. Our Series paper describes how our understanding of the roles of the microcirculation, inflammation, and coagulation has shaped new and emerging treatment strategies.

Pharmacological modulation of oxidative stress response in minimally invasive surgery: systematic review

This systematic review aims to synthesize the data on the effectiveness of pharmacological modulation of stress response in minimally invasive surgery. Eligible trials were clinical trials randomized or not or experimental trials that investigated the effect of pharmacological agents on modulation of surgical stress response to minimally invasive surgery. No clinical trials were identified. Eight experimental trials met the inclusion criteria and were obtained in full text. Experimental models were rats or rabbits subjected to pneumoperitoneum, or pneumoretroperitoneum, not to a whole operation. Pharmacological modulation of surgical stress response was attempted with erythromycin, melatonin, mesna, verapamil, pentoxifylline, N-acetylcysteine, and zinc. All the pharmacological agents, except pentoxifylline, seemed to reduce oxidative stress markers. However, only mesna pretreatment prevented oxidative stress, because oxidative stress markers remained in the sham levels. Contrasting data were obtained for pentoxyphilline. In conclusion, available data suggest that pharmacological modulation of surgical stress response to minimally invasive surgery might be feasible.

Systems biology of antioxidants

Understanding the role of oxidative injury will allow for therapy with agents that scavenge ROS (reactive oxygen species) and antioxidants in the management of several diseases related to free radical damage. The majority of free radicals are generated by mitochondria as a consequence of the mitochondrial cycle, whereas free radical accumulation is limited by the action of a variety of antioxidant processes that reside in every cell. In the present review, we provide an overview of the mitochondrial generation of ROS and discuss the role of ROS in the regulation of endothelial and adipocyte function. Moreover, we also discuss recent findings on the role of ROS in sepsis, cerebral ataxia and stroke. These results provide avenues for the therapeutic potential of antioxidants in a variety of diseases.

Antioxidant supplementation attenuates oxidative stress in chronic hepatitis C patients

Reactive oxygen species (ROS) overgeneration is involved in the pathogenesis of hepatitis C. The aim of this study was to evaluate the antioxidant status in the blood of HCV infected patients treated or not with standard therapy before and after supplementation of vitamins E, C and zinc. Biomarkers of oxidative stress were evaluated in the blood of three groups of patients: group 1 - controls; group 2 - HCV patients without treatment examined before and after a daily antioxidant supplementation (vitamin E 800 mg, C 500 mg and zinc 40 mg) for 6 months; and group 3 - HCV patients treated with pegylated interferon combined with ribavirin, also examined before and after the same antioxidant supplementation. Before antiviral treatment HCV patients showed enhanced superoxide dismutase, catalase and glutathione peroxidase activities and decreased glutathione reductase activity, while lipoperoxidation was increased and reduced glutathione showed decreased levels compared to controls. Treatment with standard therapy enhanced the activities of catalase and glutathione S-transferase, increased contents of protein carbonyl and promoted further reduced glutathione depletion. After antioxidant supplementation, decreased catalase and glutathione S-transferase activities, decreased lipoperoxidation in group 2, and increased reduced glutathione contents in both supplemented groups were detected. Before antioxidant supplementation, alanine aminotransferase and gamma glutamyl transferase contents showed significant increases in group 2.

CONCLUSION

Untreated HCV patients and also those treated with the standard therapy are coping with a systemic oxidative stress. The antioxidant supplementation conferred an antioxidant protection to both supplemented groups attenuating oxidation processes related to the disease.

Antioxidants and micronutrient supplementation in trauma patients

PURPOSE OF REVIEW

This study reviews important nutrients responsible for oxidant-antioxidant balance in trauma patients requiring admission to the ICU and rationale for repletion of antioxidants using pharmaconutrition.

RECENT FINDINGS

Oxidative stress is an underlying cause of critical illness due to oxidant-antioxidant imbalance. Multiple nutrients important to oxidative balance have been studied, yet much variety exists among the dosing, timing, and route of administration. Conflict also exists regarding the benefits of particular single nutrients and the effects of combination therapy. Anticipated results of the Reducing Deaths due to Oxidative Stress trial hope to provide further insight to the use of antioxidants in critically ill patients.

SUMMARY

The goal of this review, though not exhaustive, serves to highlight recent significant studies regarding antioxidant use in the ICU setting while calling for sufficiently powered randomized, controlled trials to elucidate appropriate guidelines for antioxidant administration in regards to ideal dosing, route of administration, timing of administration, duration of therapy, and the role of single versus combination supplementation.

Oxidative stress

Oxidative stress is defined by an imbalance between increased levels of reactive oxygen species (ROS) and a low activity of antioxidant mechanisms. An increased oxidative stress can induce damage to the cellular structure and potentially destroy tissues. However, ROS are needed for adequate cell function, including the production of energy by the mitochondria. Increased oxidative stress has been incriminated in physiological conditions, such as aging and exercise, and in several pathological conditions, including cancer, neurodegenerative diseases, cardiovascular diseases, diabetes, inflammatory diseases, and intoxications. However, prevention by antioxidants has been mostly inefficient. Therefore, a rigorous scientific evaluation in well-defined conditions is mandatory to define the appropriate place for manipulations of the oxidative pathways in human medicine.

Vitamin C in sepsis

Bacterial bloodstream infection causes septic syndromes that range from systemic inflammatory response syndrome (SIRS) and encephalopathy to severe sepsis and septic shock. Microvascular dysfunction, comprising impaired capillary blood flow and arteriolar responsiveness, precedes multiple organ failure. Vitamin C (ascorbate) levels are low in critically ill patients. The impact of ascorbate administered orally is moderate because of its limited bioavailability. However, intravenous injection of ascorbate raises plasma and tissue concentrations of the vitamin and may decrease morbidity. In animal models of polymicrobial sepsis, intravenous ascorbate injection restores microvascular function and increases survival. The protection of capillary blood flow and arteriolar responsiveness by ascorbate may be mediated by inhibition of oxidative stress, modulation of intracellular signaling pathways, and maintenance of homeostatic levels of nitric oxide. Ascorbate scavenges reactive oxygen species (ROS) and also inhibits the NADPH oxidase that synthesizes superoxide in microvascular endothelial cells. The resulting changes in redox-sensitive signaling pathways may diminish endothelial expression of inducible nitric oxide synthase (iNOS), tissue factor and adhesion molecules. Ascorbate also regulates nitric oxide concentration by releasing nitric oxide from adducts and by acting through tetrahydrobiopterin (BH4) to stimulate endothelial nitric oxide synthase (eNOS). Therefore, it may be possible to improve microvascular function in sepsis by using intravenous vitamin C as an adjunct therapy.

Micronutrient supplementation for critically ill adults: a systematic review and meta-analysis

OBJECTIVE

This systematic review assessed the effects of micronutrient supplementation on adults recovering from critical illness. Primary outcomes included clinical endpoints (mortality, infectious complications, length of intensive care unit and of hospital stay). Secondary outcomes included descriptions of practice issues, micronutrient status, morbidity, course of the acute-phase response, and oxidative stress.

METHODS

Electronic bibliographic databases, bibliographies of retrieved articles, and personal files were searched and reviewed. Randomized controlled trials (RCTs) of micronutrient supplementation in adult critically ill patients administered enterally and/or parenterally in addition to their routine care were included. Two authors independently extracted data and assessed trial quality. The random-effects model was used to estimate overall relative risk (RR)/mean difference and effect size. P<0.05 was considered statistically significant.

RESULTS

Fifteen (n=1714) and 18 (n=1849) RCTs were included for the primary and secondary objectives, respectively. Fourteen trials (n=1468) showed a statistically significant decrease in overall mortality (RR 0.78, 95% confidence interval 0.67-0.90, I2=0%, P=0.0009). Six RCTs (n=1194) indicated a statistically significant decrease in 28-d mortality (RR 0.75, 95% confidence interval 0.63-0.88, I2=0%, P=0.0006). Micronutrient supplementation was not associated with a decrease in infectious complications, length of intensive care unit, or length of hospital stay. In subgroup analyses, a sensitivity analysis of combined micronutrients indicated a significant decrease in mortality (RR 0.69, 95% confidence interval 0.54-0.90, I2=2%, P=0.006). The secondary outcomes confirmed that timing, duration, and dosing appear to be key factors to ensure optimal clinical benefit.

CONCLUSION

This review does suggest a potential benefit of micronutrient supplementation in critically ill adults by possibly being associated with a decrease in mortality.

Post-exposure antioxidant treatment in rats decreases airway hyperplasia and hyperreactivity due to chlorine inhalation

We assessed the safety and efficacy of combined intravenous and aerosolized antioxidant administration to attenuate chlorine gas-induced airway alterations when administered after exposure. Adult male Sprague-Dawley rats were exposed to air or 400 parts per million (ppm) chlorine (a concentration likely to be encountered in the vicinity of industrial accidents) in environmental chambers for 30 minutes, and returned to room air, and they then received a single intravenous injection of ascorbic acid and deferoxamine or saline. At 1 hour and 15 hours after chlorine exposure, the rats were treated with aerosolized ascorbate and deferoxamine or vehicle. Lung antioxidant profiles, plasma ascorbate concentrations, airway morphology, and airway reactivity were evaluated at 24 hours and 7 days after chlorine exposure. At 24 hours after exposure, chlorine-exposed rats had significantly lower pulmonary ascorbate and reduced glutathione concentrations. Treatment with antioxidants restored depleted ascorbate in lungs and plasma. At 7 days after exposure, in chlorine-exposed, vehicle-treated rats, the thickness of the proximal airways was 60% greater than in control rats, with twice the amount of mucosubstances. Airway resistance in response to methacholine challenge was also significantly elevated. Combined treatment with intravenous and aerosolized antioxidants restored airway morphology, the amount of airway mucosubstances, and airway reactivity to control levels by 7 days after chlorine exposure. Our results demonstrate for the first time, to the best of our knowledge, that severe injury to major airways in rats exposed to chlorine, as characterized by epithelial hyperplasia, mucus accumulation, and airway hyperreactivity, can be reversed in a safe and efficacious manner by the post-exposure administration of ascorbate and deferoxamine.

Acute phase response of selenium status and glutathione peroxidase activity in blood plasma before and after total knee arthroplasty surgery

Several studies show the consistent results of the decrease in plasma or serum selenium (Se) after surgery, and the change is suggested to be a negative acute phase response of Se to the surgical inflammation. Plasma glutathione peroxidase (GPx), which is included in the acute phase response proteins, is a selenoenzyme. However, previous studies failed to show any changes in GPx activity before and after surgery. In the present study, we investigated the Se- and selenoenzyme responses that accompany the acute inflammatory reactions during and following major surgery. Patients who underwent elective total knee arthroplasty surgery due to knee osteoarthritis at the Department of Orthopaedic Surgery at Gunma University Hospital in Japan were studied. The plasma Se concentration was determined, and the activity of plasma GPx was measured. C-reactive protein (CRP), albumin, blood urea nitrogen (BUN), and white blood cell (WBC) count were also analysed. Increases in the inflammatory biomarkers of CRP and WBC showed inflammatory reactions with the surgery. A significant increase in plasma GPx activity (p < 0.05) and decreases in the plasma Se concentration (p < 0.05) and in serum albumin (p < 0.05) after surgery were observed. Since albumin is a Se-containing protein and represents a negative acute phase protein that provides amino acids for the production of other series of acute phase proteins, the present results suggest that there is a redistribution of plasma Se to GPx that occurs as an acute phase response, and the source of Se for GPx could be, at least partly, from albumin.

Endurance exercise attenuates ventilator-induced diaphragm dysfunction

Controlled mechanical ventilation (MV) is a life-saving measure for patients in respiratory failure. However, MV renders the diaphragm inactive leading to diaphragm weakness due to both atrophy and contractile dysfunction. It is now established that oxidative stress is a requirement for MV-induced diaphragmatic proteolysis, atrophy, and contractile dysfunction to occur. Given that endurance exercise can elevate diaphragmatic antioxidant capacity and the levels of the cellular stress protein heat shock protein 72 (HSP72), we hypothesized that endurance exercise training before MV would protect the diaphragm against MV-induced oxidative stress, atrophy, and contractile dysfunction in female Sprague-Dawley rats. Our results confirm that endurance exercise training before MV increased both HSP72 and the antioxidant capacity in the diaphragm. Importantly, compared with sedentary animals, exercise training before MV protected the diaphragm against MV-induced oxidative damage, protease activation, myofiber atrophy, and contractile dysfunction. Further, exercise protected diaphragm mitochondria against MV-induced oxidative damage and uncoupling of oxidative phosphorylation. These results provide the first evidence that exercise can provide protection against MV-induced diaphragm weakness. These findings are important and establish the need for future experiments to determine the mechanism(s) responsible for exercise-induced diaphragm protection.

A new enteral diet, MHN-02, which contains abundant antioxidants and whey peptide, protects against carbon tetrachloride-induced hepatitis

BACKGROUND

Inflammatory or oxidative stress is related to various diseases, including not only inflammatory diseases, but also diabetes, cancer, and atherosclerosis. The aim of this study was to evaluate the anti-inflammatory effects of a new enteral diet, MHN-02, which contains abundant antioxidants and whey peptide. The study also investigated the ability of MHN-02 to attenuate lethality, liver injury, the production of inflammatory cytokines, and the production of oxidized products using a carbon tetrachloride-induced rat model of severe fulminant hepatitis.

METHODS

Male Sprague-Dawley rats were fed either a control diet or the MHN-02 diet for 14 days and injected with 2 mL/kg of carbon tetrachloride. Survival of rats was monitored from day 0 to day 3. To evaluate liver injury, inflammation, and oxidative stress, blood and liver samples were collected, and aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, interleukin 6, tumor necrosis factor-α, and superoxide dismutase activity as a free radical scavenger were measured. A portion of the liver was evaluated histologically.

RESULTS

The survival rates of rats receiving the MHN-02 diet and the control diet were 90% and 55%, respectively. In the MHN-02 diet group, levels of serum liver enzymes and serum cytokines were significantly lower than in the control group. Superoxide dismutase activity in the MHN-02 diet was significantly higher in the MHN-02 group. Pathological lesions were significantly larger in the control group.

CONCLUSION

Supplementation of enteral diets containing whey peptide and antioxidants may protect against severe hepatitis.

Oral preoperative antioxidants in pancreatic surgery: a double-blind, randomized, clinical trial

OBJECTIVE

Oxidative stress due to ischemia/reperfusion injury increases systemic inflammation and impairs immune defenses. Much interest has developed for the administration of antioxidant substrates in surgical patients. The purpose of this study was to perform a pilot evaluation of the impact of a carbohydrate- containing preconditioning oral nutritional supplement (pONS) enriched with glutamine, antioxidants, and green tea extract on postoperative oxidative stress.

METHODS

We performed a double-blind placebo-controlled randomized clinical trial, involving 36 cancer patients undergoing pancreaticoduodenectomy. Patients were randomized to receive either pONS or placebo twice the day before surgery and once 3 hours before surgery. Total endogenous antioxidant capacity (TEAC), plasma levels of vitamin C, vitamin E, selenium, zinc, F2-isoprostanes, and C-reactive protein were measured at baseline and on postoperative day (POD) 1, 3, and 7.

RESULTS

At surgery, the mean gastric residual volume (mL) was 54.2 in the pONS group versus 51.3 in the placebo group (P = NS). On POD 1 plasma levels of vitamin C (P = 0.001), selenium (P = 0.07), and zinc (P = 0.06) were higher in the pONS group compared to placebo. TEAC was improved on POD 1, 3, and 7 in the pONS group compared to placebo (P = 0.01). No difference was found in plasma C-reactive protein levels after surgery in both groups.

CONCLUSIONS

Perioperative pONS administration positively affected plasma vitamin C levels and improved TEAC shortly after surgery, but did not reduce oxidative stress and systemic inflammation markers.

Cytoprotective effect of γ-tocopherol against tumor necrosis factor α induced cell dysfunction in L929 cells

The antioxidant vitamin γ-tocopherol exerts protective and anti-inflammatory effects in various models of critical illness. The combination of actinomycin D and tumor necrosis factor α (TNFα) in the immortalized fibroblast cell line L929 is a well-established method to model pro-inflammatory cytotoxicity in cultured cells in vitro. The present study had two aims. First, we wished to characterize the contribution of reactive oxygen species (ROS) to the cell dysfunction and this commonly used model system of cell death. Second, we wished to investigate the effects of γ-tocopherol on this response. Cells were exposed to actinomycin D (0.5 µg/ml) + TNFα (100 pg/ml) in the absence or presence of 1 h of γ-tocopherol pre-treatment. The earliest change that was detected in our system in response to TNFα was an increase in mitochondrial oxidant production, already apparent at 45 min. Changes in glycolysis and oxidative phosphorylation parameters were already apparent at 2 h, as detected by the Seahorse Biosciences XF24 Flux Analyzer. By 6 h, a slight decrease in Cell Index was detected by impedance-based analysis, employing an electronic sensor array system (XCelligence). At the same time, a slight decrease in cell viability was detected by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) method, along with a significant increase in lactate dehydrogenase (LDH) release into the culture medium, and a detectable degree of mitochondrial membrane depolarization. Between 12 and 24 h, the cell viability (already at a low level) further declined, which coincided with a secondary, marked decline in the mitochondrial membrane potential. Pre-treatment of the cells with γ-tocopherol (10-300 µM) provided a significant protection against all of the functional alterations induced by actinomycin D and TNFα. The current study provides direct evidence that reactive oxidant formation plays an important role in the current experimental model of cell dysfunction, and demonstrates the protective effects of the potent endogenous antioxidant vitamin, γ-tocopherol. The mechanisms described in the current study may, in part, contribute to the protective effects of γ-tocopherol in various models of critical illness.