Serum and Urine Biomarker Elevation Indicating the Onset of Deep Tissue Injury as Examined on a Rat Model

Deep tissue injury (DTI) is a serious pressure ulcer (PU) which initiates in deep tissue, mainly muscle, and progresses rapidly to a full-thickness wound [1, 2]. Therefore, an early indication should help in increasing awareness and providing prompt intervention to prevent it from progressing to an open wound, which is susceptible to infection and typically needs prolonged and aggressive care. However, the diagnosis of DTI is currently still vague at best[2] with only subjective tools. This situation calls for tools for objectively sensing the tissue changes while the skin is still intact, to allow development of evidence-based protocols for early diagnosis and treatment. Since DTI initiates from deep muscle layer around a bony prominence, a tool that sensitive to muscle damage may have the potential to objectively sense the onset of a DTI in clinical application. A number of molecular biomarkers have been reported in the literature as suitable for indicating muscle damage. Some of the most promising biomarkers are myoglobin and heart-type fatty acid binding protein (H-FABP). Myoglobin and H-FABP are two relatively small muscle proteins that show a very fast release time after skeletal muscle damage/necrosis when no myocardial infarction or damage is present; therefore, they may be used to identify skeletal muscle injury in DTI formation. The objective of this study was to initially test whether myoglobin and H-FABP in serum and urine respond quickly to pressure induced deep tissue injury on a rat model. It is expected that knowledge gained from this study may lead to a promising new methodology to sense the visually invisible DTI.