Sepsis induces extensive autophagic vacuolization in hepatocytes: a clinical and laboratory-based study

Autophagy is the regulated process cells use to recycle nonessential, redundant, or inefficient components and is an adaptive response during times of stress. In addition to its function in enabling the cell to gain vital nutrients in times of stress, autophagy can also be involved in elimination of intracellular microorganisms, tumor suppression, and antigen presentation. Because of difficulty in diagnosing autophagy, few clinical studies have been performed. This study examined whether autophagy occurs in hepatocytes during sepsis. Electron microscopy (EM) was performed on liver samples obtained from both an observational clinical cohort of six septic patients and four control patients as well as liver specimens from mice with surgical sepsis (by cecal ligation and puncture) or sham operation. EM demonstrated increased autophagic vacuoles in septic vs nonseptic patients. Randomly selected fields (3000 μm2) from control and septic patients contained 1.2±1.5 vs 5.3±3.3 (mean±s.d.) complex lysosomal/autophagolysosomal structures per image respectively (P