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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
2009-4-28
pubmed:abstractText
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 microm(2)) 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<0.001). In rare instances, hepatocytes with autophagic vacuoles appeared to be unequivocally committed to death. Membrane alterations (membrane vacuoles, invagination into adjacent organelles, and myelin figure-like changes) occur in a subpopulation of mitochondria in sepsis, but other hepatocyte organelles showed no consistent ultrastructural injury. Findings in murine sepsis paralleled those of patients, with 7.2+/-1.9 vs 38.7+/-3.9 lysosomal/autophagolysosomal structures in sham and septic mice, respectively (P=0.002). Quantitative RT-PCR demonstrated that sepsis induced the upregulation of select apoptosis and cytokine gene expression with minimal changes in the core autophagy genes in liver. In conclusion, hepatocyte autophagic vacuolization increases during sepsis and is associated with mitochondrial injury. However, it is not possible to determine whether the increase in autophagic vacuolization is an adaptive response or a harbinger of cell death.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
1530-0307
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
89
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
549-61
pubmed:meshHeading
pubmed-meshheading:19188912-Adult, pubmed-meshheading:19188912-Aged, pubmed-meshheading:19188912-Animals, pubmed-meshheading:19188912-Autophagy, pubmed-meshheading:19188912-Biological Markers, pubmed-meshheading:19188912-CD4-Positive T-Lymphocytes, pubmed-meshheading:19188912-Cytokines, pubmed-meshheading:19188912-Disease Models, Animal, pubmed-meshheading:19188912-Female, pubmed-meshheading:19188912-Hepatocytes, pubmed-meshheading:19188912-Humans, pubmed-meshheading:19188912-Liver, pubmed-meshheading:19188912-Male, pubmed-meshheading:19188912-Mice, pubmed-meshheading:19188912-Mice, Inbred C57BL, pubmed-meshheading:19188912-Middle Aged, pubmed-meshheading:19188912-Mitochondria, pubmed-meshheading:19188912-Reverse Transcriptase Polymerase Chain Reaction, pubmed-meshheading:19188912-Sepsis, pubmed-meshheading:19188912-Spleen
pubmed:year
2009
pubmed:articleTitle
Sepsis induces extensive autophagic vacuolization in hepatocytes: a clinical and laboratory-based study.
pubmed:affiliation
Department of Anesthesiology, Washington University School of Medicine, St Louis, MO 63110, USA.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't, Research Support, N.I.H., Extramural