Oxidative stress (OS) contributes to cellular deterioration, resulting in decreases in physiological reserve. Imbalance of oxidative stress pathways lead to damage and drive the aging process and frailty. Study goals were to determine if a new plasma biomarker of oxidative stress is related to: 1) oxidation reduction status in patients who have experienced traumatic injury as well as healthy community dwellers, 2) outcomes of patients who have experienced trauma, 3) frailty measured by established frailty scales in healthy community dwellers.
Methods:
This prospective study included 1) trauma patient’s ≥65 years of age admitted to a suburban Level 1 trauma center between 6/12/14-12/30/14 and 2) age and gender matched healthy, community-dwelling volunteers. Plasma samples (40μL) were tested in duplicate for capacity ORP(cORP, uC; antioxidant reserve), and static ORP (sORP, mV; the current state of OS). Frailty assessments were performed in healthy participants using established frailty scales. ORP measurements were analyzed using correlation analyses. Univariate analysis was used to analyze cORP and sORP for differences by gender and by the presence/absence of the following variables in both the injured and healthy control populations: current smoker, pre-injury diabetes mellitus (DM), statin use, vitamin use, and any alcohol consumption.
Results:
186 subjects were included in the study (n=93 for both groups). Nearly half of the trauma patients (44%) were admitted due to a Traumatic Brain Injury; Injury Severity Scores were low (median [interquartile range] = 9.0 [5-13]). In the trauma population, cORP values were significantly lower in patients with Diabetes (p<0.05) and in patients that smoked (p<0.01). Similar results were found in the healthy group for smoking and diabetes (p<0.05). In healthy participants a lack of vitamin use was also related to lower cORP values (p<0.05), however there were no differences in sORP in the healthy volunteers. There were no significant differences based on gender, statin or alcohol use for either group. Significant correlation was found for both sORP and cORP with CSHA Clinical Frailty Scale in the healthy group.
Conclusion:
Findings suggest that the variables of smoking and diabetes are contributory to frailty trajectory. Data suggest the capacity to tolerate oxidative stress, measured by cORP, is lower in aged individuals that smoke or are diabetic and contributes to frailty as a result of oxidative damage. These frailty markers may be used in the emergent and post emergent injury phases of care. The finding that there is an increase in the sORP and a decrease in cORP in these patient populations puts them at higher risk suggests a progressive loss of redundancy in physiological systems in response to oxidative stress.