Jack of all trades: pleiotropy and the application of chemically modified tetracycline-3 in sepsis and the acute respiratory distress syndrome (ARDS).

Sepsis is a disease process that has humbled the medical profession for centuries with its resistance to therapy, relentless mortality, and pathophysiologic complexity. Despite 30 years of aggressive, concerted, well-resourced efforts the biomedical community has been unable to reduce the mortality of sepsis from 30%, nor the mortality of septic shock from greater than 50%. In the last decade only one new drug for sepsis has been brought to the market, drotrecogin alfa-activated (Xigris™), and the success of this drug has been limited by patient safety issues. Clearly a new agent is desperately needed. The advent of recombinant human immune modulators held promise but the outcomes of clinical trials using biologics that target single immune mediators have been disappointing. The complex pathophysiology of the systemic inflammatory response syndrome (SIRS) is self-amplifying and redundant at multiple levels. In this review we argue that perhaps pharmacologic therapy for sepsis will only be successful if it addresses this pathophysiologic complexity; the drug would have to be pleiotropic, working on many components of the inflammatory cascade at once. In this context, therapy that targets any single inflammatory mediator will not adequately address the complexity of SIRS. We propose that chemically modified tetracycline-3, CMT-3 (or COL-3), a non-antimicrobial modified tetracycline with pleiotropic anti-inflammatory properties, is an excellent agent for the management of sepsis and its associated complication of the acute respiratory distress syndrome (ARDS). The purpose of this review is threefold: (1) to examine the shortcomings of current approaches to treatment of sepsis and ARDS in light of their pathophysiology, (2) to explore the application of COL-3 in ARDS and sepsis, and finally (3) to elucidate the mechanisms of COL-3 that may have potential therapeutic benefit in ARDS and sepsis.