Sepsis is a life-threatening complication of infection that results in over 250,000 deaths per year in the United States. There is a strong correlation between reduced levels of lymphocytes, such as CD8+ and CD4+ T cells, and increased mortality; therefore, strategies aimed to increase these cells have therapeutic potential. The cytokine IL-7 prevents lymphocyte death, increases lymphocyte proliferation, and has been shown to improve intestinal lymphocyte counts in patients with HIV-1. In this episode, Richard Hotchkiss details the results from a prospective, randomized, double-blind, placebo-controlled trial of recombinant human IL-7 in patients with septic shock and severe lymphocytopenia. IL-7 reversed the loss of lymphocytes in septic patients, suggesting that this approach be further explored.
Hepatic stellate cells (HSCs) are key mediators of liver fibrosis; however, the pathways that drive HSC migration, proliferation, and ECM production in response hepatic injury are not fully understood. In this episode, Vijay Shah and colleagues show that mice lacking the scaffold protein synectin are protected from liver fibrosis. This protection associated with down regulation of PDGFR-β and PDGFR-α via distinct synectin-regulated mechanisms, thus identifying synectin as an important mediator of liver fibrosis.