The Study Of The Combination Effect Of Atorvastatin And Probucol In Preventing CI-AKI And Its Possible Mechanism

Background&Objective: Contrast-induced acute kidney injury(CI-AKI) is one of the most clinically important complications associated with the use of iodinated contrast media(CM). For nearly 2 decades, it has remained the third most common cause of acute renal failure in hospitalized patients. Atorvastatin and Probucol have been studied for their beneficial effect in preventing CI-AKI; however, little is known about the effect of their combination in this context. Inflammatory and oxidative stress may be involved in the pathogenesis of CI-AKI; thus, statins could have a significant benefit in this setting owing to their effects on anti-inflammatory and anti- oxidative stress. Recently, Atorvastatin also has been reported to be effective in extenuating endoplasmic reticulum stress(ERS)-induced apoptosis. However, whether this effect involved in the mechanism of preventing CI-AKI is still unknown. In the last few decades, efforts to detect CI-AKI in the early stage have resulted in some new biomarkers. Clusterin has been suggested as a potential biomarker for detecting AKI. Accordingly, it needs to be investigated as a more sensitive biomarker for detecting CI-AKI. The present study compared the protective effects of short-term different drugs combination and doses on renal function; investigated whether the attenuation of ERS-induced apoptosis may be involved in the renoprotective effect of atorvastatin from CI-AKI; provided insights into the use of clusterin as a new biomarker for CI-AKI.Methods: A total of 220 patients with coronary heart disease undergoing coronary angiography(CAG) and/or percutaneous coronary intervention(PCI) were assigned into low dose atorvastatin-probucol combination group(LDC, n= 54, atorvastatin 20mg/day and probucol 250 mg 3 times/day without loading dose before coronary procedure); high dose atorvastatin-probucol combination group(HDC, n=73, atorvastatin 40mg/dayand probucol 250 mg 3 times/day with loading dose of 40 mg atorvastatin and 500 mg probucol 2 hours before the procedure) and high dose atorvastatin group(HDA, n=93, atorvastatin 40mg/day with 40 mg loading dose 2 hours before the procedure). The three regimens started 24-48 hours before the invasive coronary procedure. Renal parameters(uric acid, blood urea nitrogen, serum creatinine and estimated glomerular filtration rate) were measured at 24 hours before and 48 hours after CAG/PCI. 30 Wistar rats were randomly assigned into 3 groups: control group(group N), contrast media control group(group NC) and atorvastatin group(group D). One week before and two days after injecting of contrast medium, group D was given atorvastatin(30 mg/kg), while group N and group NC were given same dose solution. Urografin was injected in the rats of group NC and group D, while same dose of saline was injected in the rats of group N. Rats were euthanized 72 hours after injection. The blood samples were collected for determination of uric acid, blood urea nitrogen and serum creatinine. Both kidneys were removed and bisected in an equatorial plane. The left kidney was fixed with the 10% formalin buffer for routine histological examination and TUNEL staining. The right kidney was stored at-80℃ for protein and m RNA analysis. Analyses were conducted using SPSS19.0 statistical software. Categorical data are presented as absolute values and percentages and were analyzed by Chi-square or Fisher’s Exact or Freeman-Halton extension of the Fisher exact test as required. Continuous variables are reported as mean value ± SD. Comparison of continuous variables within groups was performed by paired t-test or Wilcoxon-Rank test as appropriate. Samples t-test, One-way ANOVA test, ANOVA test with Tukey’s Post-hoc test, ANOVA test with LSD test, Mann-Whitney U test and Kruksal-Wallis test were used to determine differences between groups. P value <0.05 was considered statistically significant.Results: 1. 9 patients(4.7%) developed CI-AKI. The incidence was lower in HDC group comparing with LDC and HDA groups but without significant difference. Serum creatinine(Scr) was significantly higher and e GFR was significantly lowerpost-coronary intervention in LDC and HDA groups. The two parameters didn’t change significantly in HDC group. Post-procedure Scr was significantly lower in HDC group comparing with HDA group. The absolute changes(Δ SCr, Δe GFR) were not significantly different between the three groups. The three treatment regimens reduced blood urea nitrogen(BUN) significantly post-coronary intervention, while only LDC and HDC reduced uric acid(UA) significantly post-procedure. The absolute change(ΔBUN, ΔUA) were significantly lower in HDC than HDA group. Evaluating at-risk patients, the incidence of CI-AKI was significantly higher in diabetic patients and in those with higher risk score. The incidence was also higher in females and patients >70 years old with mild to moderate renal impairment. 2. Urografin induced apoptosis of renal tubular cells of rats. The expressions of GADD153 and caspase-12 were significantly up-regulated in group NC, while no similar changes was found in the expression of GRP 78. Compared with group NC, the apoptosis was significantly suppressed in group D. Compared with group N, the expressions of GADD153 and caspase-12 in group D were slightly up-regulated, but with no statistical significance. 3. The expression of clusterin in group NC was significantly up-regulated, not only at m RNA level but also at protein level.Conclusions: 1. Short term high dose atorvastatin-probucol combination could be more beneficial than low dose combination and high dose atorvastatin in protecting renal function; thus preventing CI-AKI. Diabetic patients and those with higher risk score are at high risk to develop CI-AKI. Females and elderly with baseline renal impairment are also at high risk. 2. Apoptosis might involved in the pathogenesis of urografin-induced CI-AKI. ERS-induced apoptosis pathway(at least partly) plays a role in the pathogenesis of CI-AKI. Atorvastatin may prevent CI-AKI by suppressing apoptosis through the ERS-induced apoptosis pathway. 3. Clusterin might be a new biomarker for detecting CI-AKI.