Antioxidants as therapeutics in the intensive care unit: Have we ticked the redox boxes?
Critically ill patients are under oxidative stress and antioxidant administration reasonably emerged as a promising approach to combat the aberrant redox homeostasis in this patient cohort. However, the results of the antioxidant treatments in the intensive care unit are conflicting and inconclusive. The main objective of the present review is to highlight some inherent, yet widely overlooked redox-related issues about the equivocal effectiveness of antioxidants in the intensive care unit, beyond methodological considerations. In particular, the discrepancy in the literature partially stems from: (1) the largely unspecified role of reactive species in disease onset and progression, (2) our fragmentary understanding on the interplay between inflammation and oxidative stress, (3) the complex spatiotemporal specificity of in vivo redox biology, (4) the pleiotropic effects of antioxidants and (5) the divergent effects of antioxidants according to the temporal administration pattern. In addition, two novel and sophisticated practices with promising pre-clinical results are presented: (1) the selective neutralization of reactive species in key organelles after they are formed (i.e., in mitochondria) and (2) the targeted complete inhibition of dominant reactive species sources (i.e., NADPH oxidases). Finally, the reductive potential of NADPH as a key pharmacological target for redox therapies is rationalized. In light of the above, the recontextualization of knowledge from basic redox biology to translational medicine seems imperative to perform more realistic in vivo studies in the fast-growing field of critical care pharmacology.
Intensive Care Unit, 424 General Military Hospital of Thessaloniki, Thessaloniki, Greece; Department of Physical Education and Sport Science at Serres, Aristotle University of Thessaloniki, Serres, Greece. Electronic address: nvmargar@auth.gr.
Nikos V
NV
Margaritelis
D000818:Animals; D000975:Antioxidants / Q000008:administration & dosage* / Q000009:adverse effects; D003422:Critical Care / Q000379:methods*; D016638:Critical Illness; D004334:Drug Administration Schedule; D004791:Enzyme Inhibitors / Q000008:administration & dosage; D006801:Humans; D007362:Intensive Care Units; D009249:NADP / Q000378:metabolism; D019255:NADPH Oxidases / Q000037:antagonists & inhibitors / Q000378:metabolism; D015388:Organelles / Q000187:drug effects / Q000378:metabolism; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000187:drug effects*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D013997:Time Factors
D000975:Antioxidants; D004791:Enzyme Inhibitors; D017382:Reactive Oxygen Species; D009249:NADP; D019255:NADPH Oxidases
Antioxidants; Free radicals; Intensive care unit; NADPH; Oxidative stress; Redox