The Role of Dysfunctional HDL in Severe Sepsis

Sepsis is a systemic inflammatory response to infection, which leads to acute organ dysfunction and shock. Current therapies are aimed at normalizing hemodynamic parameters during early sepsis resuscitation to reduce mortality. The investigators hypothesize that future strategies should be personalized, and should target the mediators of the septic response on an individual patient basis. One of these mediators is HDL which works by facilitating clearance of bacterial toxins, maintaining the integrity of the endothelium, and preventing inflammation, a function performed by Apo-A1. The association of HDL with cardiovascular health has been well-studied in the Caucasian and Asian populations, where research has demonstrated that HDL can become pro-inflammatory and thus may not perform its functions of being anti-inflammatory, anti-thrombotic and anti-oxidant. Such HDL is called Dys-HDL. Dys-HDL or pro-inflammatory HDL may play a pivotal role in sepsis, an area that has not been fully studied. The mechanism by which HDL becomes dysfunctional is one of debate, but the main hypothesis is through polymorphisms of Apo-A1, possibly via the myeloperoxidase enzyme, and each polymorphism produces different HDL levels and activity. These alterations can lead to increased susceptibility to septic death due to inability to neutralize lipopolysaccharide, loss of thymocyte apoptosis (critical for protection against sepsis) and endogenous corticosteroid release, and loss of the ability to preserve HDLs antioxidant properties. Dys-HDL has also been demonstrated in early sepsis and may serve as a potential early disease marker. For these reasons, the investigators believe that Dys-HDL may play a pivotal role in the sepsis cascade which leads to organ dysfunction and death. Aim 1. Determine the presence of Dys-HDL in adult patients with early severe sepsis who present to the ED. Aim 2. Examine the relationship between Dys-HDL and cumulative organ dysfunction as measured by the sequential organ failure assessment (SOFA) score, a validated measure of organ dysfunction in severe sepsis.