Vitamin E supplementation in the critically ill patient: too narrow a view?

Efficacy of Acetylcysteine and Selenium in Aneurysmal Subarachnoid Hemorrhage Patients: A Prospective, Multicenter, Single Blind Randomized Controlled Trial

BACKGROUND

Subarachnoid hemorrhage (SAH) patients have oxidative stress results in inflammation, tissue degeneration and neuronal damage. These deleterious effects cause aggravation of the perihematomal edema (PHE), vasospasm, and even hydrocephalus. We hypothesized that antioxidants may have a neuroprotective role in acute aneurysmal SAH (aSAH) patients.

METHODS

We conducted a prospective, multicenter randomized (single blind) trial between January 2017 and October 2019, investigating whether antioxidants (acetylcysteine and selenium) have the potential to improve the neurologic outcome in aSAH patients. The antioxidant patient group received antioxidants of acetylcysteine (2,000 mg/day) and selenium (1,600 µg/day) intravenously (IV) for 14 days. These drugs were administrated within 24 hours of admission. The non-antioxidant patient group received a placebo IV.

RESULTS

In total, 293 patients were enrolled with 103 patients remaining after applying the inclusion and exclusion criteria. No significant differences were observed in the baseline characteristics between the antioxidant (n = 53) and non-antioxidant (n = 50) groups. Among clinical factors, the duration of intensive care unit (ICU) stay was significantly shortened in patients who received antioxidants (11.2, 95% confidence interval [CI], 9.7-14.5 vs. 8.3, 95% CI, 6.2-10.2 days, P = 0.008). However, no beneficial effects were observed on radiological outcomes.

CONCLUSION

In conclusion, antioxidant treatment failed to show the reduction of PHE volume, mid-line shifting, vasospasm and hydrocephalus in acute SAH patients. A significant reduction in ICU stay was observed but need more optimal dosing schedule and precise outcome targets are required to clarify the clinical impacts of antioxidants in these patients.

TRIAL REGISTRATION

Clinical Research Information Service Identifier: KCT0004628.

Rutin- and Selenium-attenuated cadmium-induced testicular pathophysiology in rats

Cadmium (Cd) is known to cause oxidative damage in the testes of rats. The aim of this study was to investigate the protective role of rutin (RUT, 30 mg/kg) and selenium (Se, 0.15 ppm) alone or in combination against Cd (200 ppm)-induced lipid peroxidation, steroidogenesis and changes in antioxidant defence system in the rat testes. The obtained results showed that Cd increased lipid peroxidation and abnormal sperm count and decreased plasma testosterone, lactate dehydrogenase, acid phosphatase, alkaline phosphatase and testicular steroidogenic enzymes: 3β-hydroxysteroid dehydrogenase (HSD), 17β-HSD activities as well as epididymal sperm counts and motility, while RUT and Se treatment reversed this change to control values. Acute intoxication with Cd was also followed by significantly decreased activity of the antioxidant defence system (superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), glutathione reductase (GR), glutathione (GSH), and glutathione-S-transferase (GST)). Treatment with RUT and Se reversed Cd-induced alterations of antioxidant defence system and significantly prevented Cd-induced testes damage and depletion of plasma and testicular Se levels. RUT and Se appear not to have more profound effects than their separate effects against Cd-induced testicular toxicity, although Se was more potent than RUT in the recovery of testosterone levels. These results suggest that both RUT and Se do not have synergistic role against Cd-induced testicular injury.

Vitamin E transfer from lipid emulsions to plasma lipoproteins: mediation by multiple mechanisms

The present study determined alpha-tocopherol mass transfer from an alpha-tocopherol-rich emulsion to LDL and HDL, and assessed the potential of different mechanisms to modulate alpha-tocopherol transfers. Emulsion particles rich in alpha-tocopherol were incubated in vitro with physiological concentrations of LDL or HDL. The influence of plasma proteins was assessed by adding human lipoprotein poor plasma (LPP) fraction with intact vs heat inactivated PLTP, or with a specific cholesteryl ester transfer protein (CETP) inhibitor, or by adding purified PLTP or pig LPP which lacks CETP activity. After 4 h incubation in absence of LPP, alpha-tocopherol content was increased by ~80% in LDL and ~160% in HDL. Addition of LPP markedly enhanced alpha-tocopherol transfer leading to 350-400% enrichment in LDL or HDL at 4 h. Higher (~10 fold) enrichment was achieved after 20 h incubation with LPP. Facilitation of alpha-tocopherol transfer was (i) more than 50% higher with human vs pig LPP (despite similar PLTP phospholipid transfer activity), (ii) reduced by specific CETP activity inhibition, (iii) not fully suppressed by heat inactivation, and (iv) not restored by purified PLTP. In conclusion, alpha-tocopherol content in LDL and HDL can be markedly raised by rapid transfer from an alpha-tocopherol-rich emulsion. Our results indicate that alpha-tocopherol mass transfer between emulsion particles and lipoproteins is mediated by more than one single mechanism and that this transfer may be facilitated not only by PLTP but likely also by other plasma proteins such as CETP.

Antioxidant nutrients: a systematic review of trace elements and vitamins in the critically ill patient

OBJECTIVE

Critical illness is associated with the generation of oxygen free radicals and low endogenous antioxidant capacity leading to a condition of oxidative stress. We investigated whether supplementing critically ill patients with antioxidants, trace elements, and vitamins improves their survival.

METHODS

We searched four bibliographic databases from 1980 to 2003 and included studies that were randomized, reported clinically important endpoints in critically ill patients, and compared various trace elements and vitamins to placebo.

RESULTS

Eleven articles met the inclusion criteria. When the results of all the trials were aggregated, overall antioxidants were associated with a significant reduction in mortality [Risk Ratio (RR) 0.65, 95% confidence intervals (CI) 0.44-0.97, p=0.03] but had no effect on infectious complications. Studies that utilized a single trace element were associated with a significant reduction in mortality [RR 0.52, 95% CI 0.27-0.98, p=0.04] whereas combined antioxidants had no effect. Studies using parenteral antioxidants were associated with a significant reduction in mortality [RR 0.56, 95% CI 0.34-0,92, p=0.02] whereas studies of enteral antioxidants were not. Selenium supplementation (alone and in combination with other antioxidants) may be associated with a reduction in mortality [RR 0.59, 95% CI 0.32-1.08, p=0.09] while nonselenium antioxidants had no effect on mortality.

CONCLUSIONS

Trace elements and vitamins that support antioxidant function, particularly high-dose parenteral selenium either alone or in combination with other antioxidants, are safe and may be associated with a reduction in mortality in critically ill patients.

Oxidative stress in critical care: is antioxidant supplementation beneficial?

Reactive oxygen species (ROS) are constantly produced in human beings under normal circumstances. Antioxidant systems help defend the body against ROS but may be overwhelmed during periods of oxidative stress, which can cause lipid peroxidation, damage to DNA, and cell death. Critical illness, such as sepsis or adult respiratory distress syndrome, can drastically increase the production of ROS and lead to oxidative stress. Sources of oxidative stress during critical illness include activation of the phagocytic cells of the immune system (the respiratory burst), the production of nitric oxide by the vascular endothelium, the release of iron and copper ions and metalloproteins, and the vascular damage caused by ischemia reperfusion. Only indirect measurements of ROS are available, but the presence of oxidative stress in critical illness is supported by clinical studies. In general, serum antioxidant vitamin concentrations seem to decrease and measures of oxidative stress seem to increase in critically ill populations. Oxidative stress has been associated with sepsis, shock, a need for mechanical ventilation, organ dysfunction, acute respiratory distress syndrome, disseminated intravascular coagulation, surgery, and the presence of an acute-phase response. In addition, higher levels of oxidative stress seem to occur in patients with more notable injuries. Dietary supplementation with antioxidant vitamins seems to be the logical answer to decreasing serum antioxidant concentrations, but antioxidants may have adverse effects. The benefit of supplementing antioxidants in critically ill populations has not been shown and requires further study.