Abstract
Background: Kidney stiffness could change during kidney disease. We hypothesize that acute kidney injury (AKI) would increase renal stiffness. Therefore, evaluating kidney Young's modulus (YM; a measure of tissue stiffness) using shear wave elastography (SWE) might help to diagnose AKI. Methods: This research was divided into two studies. Study A: Male C57BL/6 mice were used to observe kidney YM changes induced by sepsis-associated AKI, which was established by cecal ligation and puncture (CLP). Study B included 54 consecutive critically ill patients with or without AKI. Changes in renal YM were observed. Results: Study A: CLP mice showed a significantly higher kidney YM compared with the sham group. The YM gradually increased from CLP 0 hours to CLP 24 hours, and presented a fair relationship with the renal tubular injury score ( R2 = 0.71) and serum creatinine ( R2 = 0.73). Study B: YM was easily accessible, and the intraclass correlation coefficient ranged from 0.62 to 0.84. Kidney YM was higher in AKI patients and gradually increased from non-AKI to AKI III patients. Furthermore, the YM in the upper, middle, and lower poles of the renal cortex presented a fair relationship with kidney injury molecule-1 and neutrophil gelatinase-associated lipocalin ( R2 ranging from 0.4 to 0.58), and the areas under the curve of the above five indicators for the diagnosis of AKI were 0.7, 0.73, 0.70, 0.74, and 0.79, respectively. Conclusion: SWE-derived estimates of renal stiffness are higher in AKI patients and sepsis-associated AKI mice. However, it has no advantage over NGAL and KIM-1. Trial Registration: Chinese Clinical Trial Registry No: ChiCTR2200061725. Retrospectively registered July 1, 2022, https://www.chictr.org.cn/showproj.aspx?proj=169359 .