Mechanisms of cardiac and renal dysfunction in patients dying of sepsis.
BACKGROUND
The mechanistic basis for cardiac and renal dysfunction in sepsis is unknown. In particular, the degree and type of cell death is undefined.


OBJECTIVE
To evaluate the degree of sepsis-induced cardiomyocyte and renal tubular cell injury and death.


METHODS
Light and electron microscopy and immunohistochemical staining for markers of cellular injury and stress, including connexin-43 and kidney-injury-molecule-1 (Kim-1), were used in this study.


RESULTS
Rapid postmortem cardiac and renal harvest was performed in 44 septic patients. Control hearts were obtained from 12 transplant and 13 brain-dead patients. Control kidneys were obtained from 20 trauma patients and eight patients with cancer. Immunohistochemistry demonstrated low levels of apoptotic cardiomyocytes (<1-2 cells per thousand) in septic and control subjects and revealed redistribution of connexin-43 to lateral membranes in sepsis (P < 0.020). Electron microscopy showed hydropic mitochondria only in septic specimens, whereas mitochondrial membrane injury and autophagolysosomes were present equally in control and septic specimens. Control kidneys appeared relatively normal by light microscopy; 3 of 20 specimens showed focal injury in approximately 1% of renal cortical tubules. Conversely, focal acute tubular injury was present in 78% of septic kidneys, occurring in 10.3 ± 9.5% and 32.3 ± 17.8% of corticomedullary-junction tubules by conventional light microscopy and Kim-1 immunostains, respectively (P < 0.01). Electron microscopy revealed increased tubular injury in sepsis, including hydropic mitochondria and increased autophagosomes.


CONCLUSIONS
Cell death is rare in sepsis-induced cardiac dysfunction, but cardiomyocyte injury occurs. Renal tubular injury is common in sepsis but presents focally; most renal tubular cells appear normal. The degree of cell injury and death does not account for severity of sepsis-induced organ dysfunction.
Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA.
Osamu
O
Takasu
Joseph P
JP
Gaut
Eizo
E
Watanabe
Kathleen
K
To
R Eliot
RE
Fagley
Brian
B
Sato
Steve
S
Jarman
Igor R
IR
Efimov
Deborah L
DL
Janks
Anil
A
Srivastava
Sam B
SB
Bhayani
Anne
A
Drewry
Paul E
PE
Swanson
Richard S
RS
Hotchkiss
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D016923:Cell Death; D005260:Female; D006333:Heart Failure / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry; D007684:Kidney Tubules / Q000473:pathology*; D008297:Male; D008854:Microscopy, Electron; D008875:Middle Aged; D032383:Myocytes, Cardiac / Q000473:pathology*; D051437:Renal Insufficiency / Q000473:pathology*; D018805:Sepsis / Q000473:pathology*