Kidney histopathology in lethal human sepsis

Area of Science:

• Nephrology
• Pathology
• Critical Care Medicine

Background:

• Sepsis-associated acute kidney injury (AKI) is a critical complication in critically ill patients.
• Acute tubular necrosis (ATN) is a known factor, but other histopathological drivers are understudied.

Purpose of the Study:

• To investigate additional histopathological and cellular processes contributing to sepsis-AKI.
• To characterize features in human septic kidney tissue using immunohistochemistry.

Main Methods:

• Examined leukocyte subsets, fibroblast activation, proliferation, apoptosis, and fibrin deposition in post-mortem septic kidney tissue (n=27).
• Utilized control kidney tissue from patients undergoing nephrectomy for renal carcinoma (n=12).
• Employed immunohistochemical analysis to compare septic and control kidney tissues.

Main Results:

• Increased neutrophils and macrophages were observed in glomeruli and tubulointerstitium of sepsis-AKI kidneys compared to controls.
• Predominant Type II macrophages were found in septic kidneys, with some expressing both Type I and Type II markers.
• Enhanced cell proliferation and fibrin deposition were noted in glomeruli and tubulointerstitium of sepsis-AKI kidneys.

Conclusions:

• Sepsis-AKI exhibits complex histopathological features beyond ATN.
• The heterogeneity observed necessitates comprehensive characterization of sepsis-AKI in larger patient cohorts.
• Further research on renal biopsy tissue is crucial for understanding sepsis-AKI mechanisms.