Is There a Role for Cardiomyocyte Toll-Like Receptor 4 in Endotoxemia?

Lipopolysaccharide (LPS) is thought to be an important molecule in myocardial depression in sepsis. Toll-like receptor 4 (TLR4), the lipopolysaccharide receptor, is known to underlie these responses. Because TLR4 is expressed on both cardiac myocytes and immune cells, it is unclear as to which cell type is responsible for myocyte depression. In this article, we present evidence that the early response is likely related to TLR4 on immune cells and most likely macrophages, whereas the more delayed response may involve various immune cells as well as myocytes.