Electron microscopic renal tubular injury score in ovine endotoxemia

Introduction

Sepsis-associated renal failure is a common complication of septic shock. The current study investigates whether an innovative score of electron microscopic tubular injury (EMTI) is correlated with plasma creatinine concentration in ovine endotoxemic shock.

Methods

Twenty-nine awake healthy ewes received a continuous endotoxin infusion until the mean arterial pressure (MAP) fell below 65 mmHg. Thereafter, sheep were optimally volume-resuscitated and received norepinephrine to establish a MAP of 70 ± 5 mmHg. After 12 hours animals were anesthetized and killed. Kidney tissue samples (10 per animal) were analyzed with standard transmission electron microscopy techniques. The EMTI score (0 to 12) was determined as the sum of (1) vacuolar cell degeneration (0 to 3), (2) basal membrane dissociation (0 to 3), (3) epithelial cell injury (0 to 3), and (4) luminal obstruction (0 to 3). The EMTI score was averaged as the mean value of the 10 kidney samples of each animal and was correlated with maximum plasma creatinine concentrations by Pearson product moment correlation.

Results

The EMTI score (median 5.9; 25% to 75% range 4.1 to 6.9) significantly correlated with the plasma creatinine concentration (1.19; 1.06 to 1.34) with a correlation coefficient of R = 0.371 (P = 0.0476; Figure 1).

Figure 1

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Conclusion

The EMTI score is useful to quantify alterations of renal tubular integrity and thereby reflects changes in renal function in ovine endotoxemia. Scientific use of the EMTI score may provide further insight into the pathophysiology of sepsis-associated renal failure.