Plasma Cytochrome c as Biomarker of Traumatic Injury and Predictor of Outcome

The investigators propose to determine whether plasma cytochrome c could serve as clinical
biomarker of traumatic injury by examining the relationship between plasma levels of
cytochrome c and the severity of the initial injury upon arrival to the hospital, subsequent
development of organ dysfunction, and clinical outcomes. Cytochrome c is a mitochondrial
protein that plays a crucial role in energy metabolism enabling transfer of electrons from
complex III (i.e., cytochrome c reductase) to complex IV (cytochrome c oxidase). Upon
mitochondrial injury and contingent on severity, cytochrome c may be released to the cytosol
and subsequently to the bloodstream. The rationale for this project stems from: (1)
observations at the Resuscitation Institute in animal models of cardiac arrest and
resuscitation in which plasma cytochrome c correlates directly with the severity of
post-resuscitation left ventricular dysfunction and inversely with survival and (2)
observations by others reporting a correlation between plasma cytochrome c and severity of
organ injury. The investigators hypothesize that plasma cytochrome c measured upon arrival to
the hospital reflects the severity of the initial traumatic injury resulting from the
aggregate effects of direct injury to organs, ischemic injury consequent to blood loss,
delays in stabilization, and preexistent comorbidity - all factors that can injure
mitochondria. The investigators further hypothesize that the initial cytochrome c plasma
level combined with the levels measured during the subsequent three days of hospitalization
correlate with the development of organ dysfunction, and clinical outcomes. The current
proposal is structured in three specific aims:

Specific Aim 1 (collection of blood samples and clinical data): For this aim the investigator
plans to enroll 100 consecutive trauma victims admitted to Advocate Lutheran General Hospital
(ALGH) over a period of 8 months presenting with single or multisystem injuries and meeting
specific entry and exclusion criteria developed to ensure a broad range of injury severity.
Blood will be sampled within 15 minutes of hospital arrival (e.g., in the Emergency
Department or Operating Room) and subsequently at 24, 48, and 72 hours. Plasma will be
separated and stored at −80 °C for subsequent batch measurement of cytochrome c (and other
markers of mitochondrial injury that may become available at the time of analysis) in the
Resuscitation Institute at Rosalind Franklin Univer-sity of Medicine and Science (RFUMS).
Clinical data will be extracted from tools used clinically - including the Illinois Trauma
Registry Worksheet and the medical record - and used to: (i) record severity of initial
traumatic injury by calculating the Trauma Score - Injury Severity Score (TRISS) along with a
detailed assessment of individual organs injury; (ii) estimate the severity of blood loss
based on base deficit and transfusion needs; (iii) determine subsequent development of organ
dysfunction by calculating the Multiple Organ Dysfunction Score (MODS) and the Sequential
Organ Failure Score; and (iv) assess outcomes by measuring length of stay in the Intensive
Care Unit (ICU), length of stay in the hospital, survival upon hospital discharge, and
functional status upon hospital discharge.

Specific Aim 2 (analysis of plasma cytochrome c): Frozen samples of arterial plasma, stored
at −80°C at ALGH, will be transferred to the Resuscitation Institute at RFU and cytochrome c
measured using electrochemiluminescence.

Specific Aim 3 (statistical analysis and modeling): A database devoid of patient identifiers
will be created merging the clinical information with values of plasma cytochrome c levels
and other markers as they become available. Considering the pilot nature of the project,
statistical modeling and analysis will be primarily exploratory focused on identifying
relationships between plasma cytochrome c levels upon hospital arrival and clinical elements
contributing of the severity of primary traumatic injury. The analysis and modeling will also
include examining the predictive value of the initial and subsequent plasma cytochrome c
levels on development of organ dysfunction and clinical outcomes.

The long-term goal of the project is to develop plasma cytochrome c as biomarker of traumatic
injury and other clinical conditions associated with mitochondrial injury that could be used
at the bedside - i.e., after developing point of care assays - for (1) assessing severity of
illness, (2) prognostication of outcome, and (3) clinical re-search on novel therapeutic
interventions aimed at reducing mitochondrial injury.

Inclusion criteria:

Age 18 years or older. Blunt mechanism for the primary injury. Time from injury to hospital
arrival is ≤ 2 hours Mechanical ventilation for any reason, including surgery, within the
initial 24 hours from hospital arrival.

Any one of the following:

- Systolic blood pressure <90 mmHg (Class III shock- >30 %blood loss) within 4 hours
from hospital arrival.

- Base deficit > 4 mmol/l in the first blood gas upon hospital arrival

- Transfusion of ≥ 2 units of packed red blood cells within ≤12 hours from hospital
arrival.

Exclusion Criteria (ANY SINGLE ONE):

Known disease with life expectancy <6 months. Penetrating mechanism for the primary injury.
Death within 4 hours from hospital arrival.