Resuscitation with Fresh Whole Blood Improves Long Term Restoration of Muscle Strength following Hemorrhage and Limb Ischemia‐Reperfusion Injury
Authors: Walters Thomas J. , Roe Janet L. , Aurora Amit 
Published: June 2021

Background

Extremity vascular injuries are commonplace in battlefield trauma and often result in ischemia‐reperfusion injury (I‐R). Fluid resuscitation following hemorrhage is often required. We compared the impact of resuscitation with colloid, Hextend™ (HEX), and fresh whole blood (FWB) on markers of microvascular damage and long‐term muscle function. Using a rodent model of combined hemorrhage and tourniquet induced I‐R injury, we tested the hypotheses that, compared to resuscitation with HEX, FWB 1) mitigates microvascular damage; and, 2) results in greater return of long‐term muscle strength.

Methods

Sprague Dawley rats were randomly assigned to HEX or FWB resuscitation groups and two time‐points (2 and 28 days; n = 8/group/time‐point). Anesthetized rats underwent arterial hemorrhage (42.5% blood vol.; 100% lethal without resuscitation) followed by 3 hours of tourniquet application. Subsequently, rats were resuscitated (15mL/kg body wt). At two days post‐injury, muscles of interest were harvested, weighed, and frozen for: histology; analysis for markers of inflammation, growth and angiogenic factors; and gene expression for markers of microvascular damage. Plasma was assayed for inflammatory markers. Muscle edema was calculated (wet:dry weight). At 28 day post‐injury, in vivo contractile properties of the tibialis anterior (TA) muscle were obtained, as well as muscle weight.

Results

In all animals, the MAP reached a nadir of ~40 mm Hg following hemorrhage. At 2 days, muscle edema was similarly pronounced in both HEX and FWB groups. Expression of Connexin 43 and VE cadherin was significantly higher with FWB than HEX, suggesting microvascular damage with HEX resuscitation (p = 0.04). Corroborating this outcome was the significantly higher tissue level expression of VEGF and angiogenic factors (TCK‐1 and Neuropilin‐2) with FWB compared to HEX (p ≤ 0.05). Compared to HEX, FWB resuscitation showed an increased expression of IFN‐γ and IL‐4 cytokines (p = 0.004). At 28 days post‐injury, in vivo muscle strength (peak tetanic torque) was 16% greater in FWB than in HEX (p = 0.03). This coincided with a 15% greater muscle mass in FWB versus HEX (p=0.07).

Conclusions

Compared to HEX, resuscitation with FWB mitigated damage to the microvasculature and improved return of muscle strength. The impact of FWB on mitigating microvascular damage may be a likely reason for the observed difference of muscle strength in the long term. Collectively, these results demonstrate that FWB resuscitation may provide benefits and possibly contribute to improved limb salvage. While FWB did provide a benefit, large improvements in muscle healing will require additional treatment strategies aimed at improving muscle regeneration.

Support or Funding Information

U.S. Army Medical Research and Materiel Command

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.