HMGB1 as a therapeutic target for sepsis: it's all in the timing!

Morbidity and mortality from severe sepsis remain high, despite decades of research and improvements in intensive care unit (ICU) care. There have been over 100 failed clinical trials of biological response modifiers aimed at single therapeutic targets, mostly to suppress the early pro-inflammatory responses. In the last decade, extracellular HMGB1 has emerged as a late mediator of sepsis in murine sepsis models, whose blockade improves mortality and has a wider therapeutic window than previous efforts. Although this review promulgates the use of HMGB1 inhibitor as a therapeutic target, it should be recognized that it may not be an optimal approach to the early systemic inflammatory response syndrome (SIRS) response and cytokine storm, but rather for those patients who survive their cytokine storm and present with a persistent inflammatory, immunosuppressive and catabolism response (PICS). With earlier implementation of evidence-based best care principles for treating sepsis, fewer patients are dying from early septic shock, and there is an endemic increase in sepsis survivors with dismal long-term outcomes. These patients have ongoing inflammatory processes that may well be driven by the late and continued release of HMGB1 and other damage-associated molecular patterns receptors (DAMPRs). HMGB1 therapeutics, whether antibodies or natural herbal approaches, may be one novel approach for targeting not the early, but the late persistent inflammation of sepsis survivors.