Sung Yoon Lim

Predictive factors of acute kidney injury in patients undergoing rectal surgery

Background Despite major advance in surgical techniques from open surgery to robot-assisted surgery, acute kidney injury (AKI) is still major postoperative complication in rectal surgery. The purpose of this study is to compare the incidence of postoperative AKI according to different surgical techniques and also the risk factors, outcomes of AKI in patients undergoing rectal cancer surgery. Methods A retrospective medical chart review was done in a total of 288 patients who received proctectomy because of rectal cancer from 2011 to 2013. Results The mean patient age was 62 ± 12 years, and male was 64.2%. Preoperative creatinine was 0.91 ± 0.18 mg/dL. Open surgery was performed in 9%, and laparoscopy assisted surgery or robot assisted surgery were performed in 54.8% or 36.1% of patients, respectively. AKI developed in 11 patients (3.82%), 2 (18%) of them received acute hemodialysis. Incidence of AKI was not different according to the surgical technique, however, the presence of diabetes, intraoperative shock, and postoperative ileus was associated with the development of AKI. In addition, AKI patients showed significantly longer hospital stay and higher mortality than non-AKI patients. Conclusion Our study demonstrated that despite advances in surgical techniques, incidence of postoperative AKI remains unchanged and also that postoperative AKI is associated with poor outcome. We also found that presence of diabetes, intraoperative shock and postoperative ileus are strongly associated with the development of AKI. More careful attention should be paid on high risk patients for the development of postoperative AKI regardless of surgical techniques.

The ADAMTS13-von Willebrand factor axis is involved in the pathophysiology of kidney ischemia-reperfusion injury.

The ADAMTS13‐von Willebrand factor (vWF) axis has been suggested to play a critical role in the pathophysiology of ischaemia‐reperfusion injury (IRI) in the heart or brain. Therefore, we aimed to investigate whether this axis was involved in the pathophysiology of IRI‐induced acute kidney injury.

The Impact of Preexisting Chronic Kidney Disease on the Severity and Recovery of Acute Kidney Injury

Background: Recent observational studies have shown that in chronic kidney disease (CKD) patients, a significantly smaller percentage of patients with an episode of acute kidney injury (AKI) have full recovery of renal function compared to those without CKD. However, precise mechanisms involved in the incomplete repair after AKI with preexisting CKD have not been completely ascertained. Here, we assessed the impact of preexisting CKD on the severity and recovery of AKI in a mouse model of 5/6 nephrectomy. Methods: Male CD-1 mice underwent 5/6 nephrectomy (Nx). Six weeks post surgery, ischemia reperfusion injury (IRI) or a sham operation was performed and functional, histological, and various molecular parameters were compared between them. Results: Serum creatinine level on day 1 after IRI was comparable between control and Nx mice. However, serum creatinine remained significantly higher throughout the recovery phase in Nx mice compared to control mice. mRNA and protein expression of the cell cycle regulatory proteins were persistently elevated in Nx mice and this was associated with significantly increased levels of the G1 cell cycle arrest markers. Treatment with a p53 inhibitor following IRI resulted in not only decreased expression of G1 arrest markers but also decreased fibrosis, suggesting that prolonged epithelial G1 cell cycle arrest might be partially responsible for impaired recovery from superimposed AKI on CKD. Conclusion: Taken together, reduced nephron mass have a negative effect on the repair process that is partially mediated by the disruption of the cell cycle regulation.

Urinary Tissue Inhibitor of Metalloproteinase and Insulin-like Growth Factor–7 as Early Biomarkers of Delayed Graft Function After Kidney Transplantation

BACKGROUND Recently, urinary tissue inhibitor of metalloproteinase-2 (TIMP-2) and insulin-like growth factor-7 (IGFBP-7), markers for G1 cell cycle arrest, have been identified and validated in predicting the development of acute kidney injury in critically ill patients. It is unknown, however, whether these two biomarkers could predict the development of delayed graft function (DGF) after kidney transplantation (KT). METHODS This is a single-center, prospective, observational study. We enrolled 74 patients who underwent KT between August 2013 and December 2016. Urine sample were collected immediately after the operation. The primary outcome was development of DGF as defined by need for dialysis of more than 1 session within 7 days of KT. RESULTS Twenty-three patients (31%) were diagnosed with DGF. In univariate analysis, kidneys from expanded criteria donors, higher donor serum creatinine, lower donor estimated glomerular filtration rate, antithymoglobulin exposure, neutrophil gelatinase associated lipocalin, and urinary [TIMP-2]·[IGFBP7] were significantly different between early graft function and DGF. However, in multivariate analysis adjusting other factors, deceased donor and urinary [TIMP-2]·[IGFBP7] at 0 hours post-transplantation could predict the development of DGF. The receiver operating characteristic curve for prediction of DGF showed an area under the curve of 0.867 (sensitivity 0.86, specificity 0.71) for a cutoff value of 1.39. CONCLUSIONS Our results indicate that urine [TIMP-2]·[IGFBP7] immediately after transplantation could be an early, predictive biomarker of DGF in kidney transplantation.

Experiences of renal transplants from donors with renal cell carcinoma after ex vivo partial nephrectomy

Purpose Routine evaluation of kidney donors occasionally reveals an incidental renal mass with an otherwise satisfactory kidney function. The use of such a kidney with an enhancing mass for transplantation is a matter of debate owing to a possible risk of transmission of donor malignancies. We report our experience of kidney transplants from donors with renal cell carcinoma, after ex vivo resection of the renal mass. Methods Two women aged 44 and 56 years were diagnosed with enhancing renal masses measuring 0.9 cm and 0.7 cm, respectively, during donor evaluation for kidney transplantation. Both patients and their families were informed of a potential risk of recurrent renal cell carcinoma following transplantation. Results Renal function test results of both donors satisfied the living donor selection criteria. Laparoscopic live donor nephrectomy was performed with ex vivo resection of renal masses on the bench table. Immediate pathological analysis revealed a renal cell carcinoma with a margin of normal renal parenchyma before transplantation. Regimens based on mammalian target of rapamycin inhibitors, which are known for their antitumoral properties, were used for immunosuppression in both recipients. None of the recipients showed recurrence or metastasis during the follow-up period, which was longer than 3 years after transplantation. Conclusion In light of the ongoing shortage of kidney donors, kidneys with small renal cell carcinoma could be considered for transplantation after appropriate removal of the lesion, with a very low risk of recurrent disease.