Novel biomarkers of oxidative stress as predictive indicators of neurological outcome after out-of-hospital cardiopulmonary arrest

Intra-arrest blood-based biomarkers for out-of-hospital cardiac arrest: A scoping review

Objective

Blood-based biomarkers play a central role in the diagnosis and treatment of critically ill patients, yet none are routinely measured during the intra-arrest phase of out-of-hospital cardiac arrest (OHCA). Our objective was to describe methodological aspects, sources of evidence, and gaps in research surrounding intra-arrest blood-based biomarkers for OHCA.

Methods

We used scoping review methodology to summarize existing literature. The protocol was designed a priori following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Extension for Scoping Reviews. Inclusion criteria were peer-reviewed scientific studies on OHCA patients with at least one blood draw intra-arrest. We excluded in-hospital cardiac arrest and animal studies. There were no language, date, or study design exclusions. We conducted an electronic literature search using PubMed and Embase and hand-searched secondary literature. Data charting/synthesis were performed in duplicate using standardized data extraction templates.

Results

The search strategy identified 11,834 records, with 118 studies evaluating 105 blood-based biomarkers included. Only eight studies (7%) had complete reporting. The median number of studies per biomarker was 2 (interquartile range 1-4). Most studies were conducted in Asia (63 studies, 53%).  Only 22 studies (19%) had blood samples collected in the prehospital setting, and only six studies (5%) had samples collected by paramedics. Pediatric patients were included in only three studies (3%). Out of eight predefined biomarker categories of use, only two were routinely assessed: prognostic (97/105, 92%) and diagnostic (61/105, 58%).

Conclusions

Despite a large body of literature on intra-arrest blood-based biomarkers for OHCA, gaps in methodology and knowledge are widespread.

Potential Role of Natural Antioxidants in Countering Reperfusion Injury in Acute Myocardial Infarction and Ischemic Stroke

Stroke and acute myocardial infarction are leading causes of mortality worldwide. The latter accounts for approximately 9 million deaths annually. In turn, ischemic stroke is a significant contributor to adult physical disability globally. While reperfusion is crucial for tissue recovery, it can paradoxically exacerbate damage through oxidative stress (OS), inflammation, and cell death. Therefore, it is imperative to explore diverse approaches aimed at minimizing ischemia/reperfusion injury to enhance clinical outcomes. OS primarily arises from an excessive generation of reactive oxygen species (ROS) and/or decreased endogenous antioxidant potential. Natural antioxidant compounds can counteract the injury mechanisms linked to ROS. While promising preclinical results, based on monotherapies, account for protective effects against tissue injury by ROS, translating these models into human applications has yielded controversial evidence. However, since the wide spectrum of antioxidants having diverse chemical characteristics offers varied biological actions on cell signaling pathways, multitherapy has emerged as a valuable therapeutic resource. Moreover, the combination of antioxidants in multitherapy holds significant potential for synergistic effects. This study was designed with the aim of providing an updated overview of natural antioxidants suitable for preventing myocardial and cerebral ischemia/reperfusion injuries.

Balance of the prooxidant and antioxidant system is associated with mortality in critically ill patients

It is well known that oxidative stress causes certain diseases and organ damage. However, roles of oxidative stress in the acute phase of critical patients remain to be elucidated. This study aimed to investigate the balance of oxidative and antioxidative system and to clarify the association between oxidative stress and mortality in critically ill patients. This cohort study enrolled 247 patients transported to our emergency department by ambulance. Blood was drawn on hospital arrival, and serum derivatives of reactive oxidant metabolites (dROMs, oxidative index) and biological antioxidant potential (BAP, antioxidative index) were measured. Modified ratio (MR) is also calculated as BAP/dROMs/7.51. There were 197 survivors and 50 non-survivors. In the non-survivors, dROMs were significantly lower (274 vs 311, p<0.01), BAP was significantly higher (2,853 vs 2,138, p<0.01), and MR was significantly higher (1.51 vs 0.92, p<0.01) compared to those in the survivors. The AUC of MR was similar to that for the APACHE II score. Contrary to our expectations, higher BAP and lower dROMs were observed on admission in non-survivors. This may suggest that the antioxidative system is more dominant in the acute phase of severe insults and that the balance toward a higher antioxidative system is associated with mortality.