Bench-to-bedside review: preventive measures for contrast-induced nephropathy in critically ill patients

Astaxanthin attenuates contrast agent-induced acute kidney injury in vitro and in vivo via the regulation of SIRT1/FOXO3a expression

PURPOSE

The study was processed to investigate the effect of astaxanthin (AST; 3,3-dihydroxybeta, beta-carotene-4,4-dione) on the acute kidney injury induced by iohexol and the relationship with SIRT1/FOXO3a signal pathway.

METHODS

Thirty male Sprague Dawley rats were randomly divided into five groups as follows: control group (CON; olive oil only), contrast media group, astaxanthin control group (100 mg/kg), low astaxanthin dose group (LAG, 50 mg/kg) and high astaxanthin dose group (HAG, 100 mg/kg). As followed, serum creatinine (SCr), blood urea nitrogen (BUN), the oxidative stress markers and apoptosis-related proteins were detected. Human proximal tubular epithelial cells (HK-2) were cultured in DMEM/F12 medium in vitro and then randomly divided into appropriate experimental groups: normal group (N), dimethyl sulfoxide (DMSO), iohexol group (I), iohexol + (1.0, 10.0 μmol/L) astaxanthin group (I + LAST; I + HAST), iohexol + SIRT1 inhibitors (nicotinamide) group (NA) and iohexol + si-RNA FOXO3a group (si-RNA FOXO3a); when cultured for 24 h, cell proliferation ability was tested by cell counting kit (CCK-8), reactive oxygen species (ROS) were detected by flow cytometry and the expression of SIRT1 and FOXO3a were observed using western blot.

RESULTS

At the end of the experiment, the levels of SCr, BUN and malondialdehyde (MDA) were all increased in the CM group. The LAG and HAG reduce superoxide anion (SOD) activity, catalase (CAT) activity, glutathione peroxidase (GPx) activity and glutathione (GSH) content, as well as SCr and BUN level. Moreover, apoptosis-associated proteins, caspase 3 p17, bax and bcl-2 were upregulated. In HK-2 cells, after adding iohexol, proliferation and intracellular ROS levels were significantly increased. Using astaxanthin in advance after the intervention, the result is opposite. SIRTl inhibitors NA can reduce the expression of SIRTl and decrease the expression of FOXO3a protein. Si-RNA FOXO3a reduces the expression of FOXO3a but had no significant effect on the expression of SIRT1.

CONCLUSIONS

Our study demonstrates that the intervention of astaxanthin could attenuate the oxidative stress and apoptosis in contrast-induced acute kidney injury (CI-AKI), and the SIRT1/FOXO3a pathway participates in the contrast-induced apoptosis of HK-2 cells. Finally, astaxanthin reduces CI-AKI by suppression of apoptosis, which may be through inhibition of SIRT1/FOXO3a pathways.

Evaluation of the protective effect of N-acetylcysteine on contrast media nephropathy

INTRODUCTION

Intravenous contrast agents can cause acute decline in kidney function, especially in patients with risk factors.

OBJECTIVES

In this study, we aimed to examine the ameliorative effect N-acetylcysteine (NAC) to reduce the incidence of contrast nephropathy.

PATIENTS AND METHODS

This study was a prospective, randomized, double-blind clinical trial on 150 patients who underwent coronary angiography. The study was carried out on patients undergoing coronary angiography. Patients were randomly assigned into 2 groups of intervention group and control subjects. Intervention group took NAC 600 mg orally twice a day. It was administered one day before angiography and continued until the second day after angiography. Control subjects received saline only. Serum creatinine was measured before and three days after coronary angiography.

RESULTS

There was no significant difference between intervention and control groups at baseline (P > 0.05). However, there was a significant decline in creatinine level among NAC patients (P = 0.001). Saline group had significantly higher proportion of nephropathy cases than NAC patients Conclusion: We found that the consumption of NAC is useful for contrast induced nephropathy (CIN) prevention.

The prevention of contrast-induced nephropathy by simultaneous hemofiltration during coronary angiographic procedures: a comparison with periprocedural hemofiltration

BACKGROUND

Periprocedural (6 h pre- and 24 h post-angiography) hemofiltration appears to effectively prevent contrast-induced nephropathy (CIN) in chronic kidney disease (CKD) patients undergoing coronary angiography. However, this procedure over-uses medical resources, and the cessation of hemofiltration during coronary angiography results in persistent renal injury. In comparison, simultaneous hemofiltration performed only during coronary angiography requires fewer medical resources and can provide instantaneous protection against CIN.

METHODS

Sixty-eight CKD patients (serum creatinine, 2.51±1.15 mg/dL) undergoing coronary angiography were randomized in a 1:2 ratio to receive either periprocedural (n=23) or simultaneous (n=45) hemofiltration. The expected CIN rate was similar for the two groups (41.3% versus 40.0%, p=0.769).

RESULTS

On day 3 after contrast exposure, four and seven patients in the periprocedural and simultaneous groups, respectively experienced CIN (17.4% versus 15.6%, p=0.846). On days 5-30, seven and three patients in the periprocedural and simultaneous groups, respectively experienced CIN (30.4% versus 6.7%, p=0.009). The serum creatinine levels of patients in the periprocedural group transiently decreased on day 1 and persistently increased during days 5-30 compared with the simultaneous group. This difference between the two groups in terms of creatinine levels over time was statistically significant (F statistic=6.830; p=0.001, by ANCOVA). The cost of hemofiltration was doubled in the periprocedural group ($1066±83 versus $504±40, p<0.001).

CONCLUSIONS

Simultaneous hemofiltration provide equal early (day 3) and better late-stage (days 5-30) renal protection against CIN at a significantly lower cost compared with periprocedural hemofiltration.

Accuracy of point-of-care serum creatinine devices for detecting patients at risk of contrast-induced nephropathy: a critical overview

Contrast-induced nephropathy (CIN) is a common event in hospitals, with reported incidences ranging from 1 to 30%. Patients with underlying kidney disease have an increased risk of developing CIN. Point-of-care (POC) creatinine devices are handheld devices capable of providing quantitative data on a patient's kidney function that could be useful in stratifying preventive measures. This overview aims to synthesize the current evidence on diagnostic accuracy and clinical utility of POC creatinine devices in detecting patients at risk of CIN. Five databases were searched for diagnostic accuracy studies or clinical trials that evaluated the usefulness of POC devices in detecting patients at risk of CIN. Selected articles were critically appraised to assess their individual risk of bias by the use of standard criteria; 13 studies were found that addressed the diagnostic accuracy or clinical utility of POC creatinine devices. Most studies incurred a moderate to high risk of bias. Overall concordance between POC devices and reference standards (clinical laboratory procedures) was found to be moderate, with 95% limits of agreement often lying between -35.4 and +35.4 µmol/L (-0.4 and +0.4 mg/dL). Concordance was shown to decrease with worsening kidney function. Data on the clinical utility of these devices were limited, but a significant reduction in time to diagnosis was reported in two studies. Overall, POC creatinine devices showed a moderate concordance with standard clinical laboratory creatinine measurements. Several biases could have induced optimism in these estimations. Results obtained from these devices may be unreliable in cases of severe kidney failure. Randomized trials are needed to address the clinical utility of these devices.

In emergency situations, should serum creatinine be checked in all patients before performing second contrast CT examinations within 24 hours?

OBJECTIVE

The aim of this study was to determine the frequency of contrast-induced nephropathy (CIN) in patients undergoing repeat contrast-enhanced computed tomographic (CT) examinations within 24 hours, as well as associated risk factors.

MATERIALS AND METHODS

Through a search of medical and radiologic records, patients who underwent 2 contrast-enhanced CT examinations within 24 hours during a 4-year period (2003-2006), with available serum creatinine measurements before and after CT imaging were included. Medical records were reviewed for demographic data, risk factors, renal status, and CT contrast volume. The frequency of CIN was calculated, and odds ratios of risk factors were determined.

RESULTS

There were 164 patients (90 men, 74 women; mean age, 56.3 years), with an average baseline serum creatinine level of 1.02 +/- 0.73 mg/dL (range, 0.3-6.6 mg/dL). Three hundred twenty-eight CT examinations were performed: 2 in each patient, at an average interval of 11.4 hours. The mean doses of contrast medium used for the first and second CT examinations were 126.2 and 123.4 mL, respectively. Twenty-one patients (12.8%) developed CIN. Comparing patients with and without CIN, the only statistically significant risk factor for CIN was an increase in serum creatinine between the first and second CT examinations, with an odds ratio of 18 (P < .005).

CONCLUSION

The incidence of CIN in patients who underwent repeat contrast-enhanced CT examinations was 12.8%. An increase in serum creatinine between the first and second CT examinations was highly associated with CIN and may serve as a risk factor for developing CIN.

Reduction of amphotericin B-induced renal tubular apoptosis by N-acetylcysteine

The reduction of amphotericin B (AmB)-induced renal tubular apoptosis and nephrotoxicity by N-acetylcysteine (NAC) in a murine model was evaluated. Four groups of rats were treated with AmB for 5 days, and each group concomitantly received two doses of 30, 60, or 120 mg of NAC/kg of body weight/day or sterile water for 5 days. Groups that received concomitant NAC at any dose had significantly decreased levels of apoptosis compared to that in animals receiving AmB only (48.8% versus 27.4, 23.6, or 23.5%, respectively; P < 0.001).

Need for quality improvement in renal systematic reviews

BACKGROUND AND OBJECTIVES

Systematic reviews of clinical studies aim to compile best available evidence for various diagnosis and treatment options. This study assessed the methodologic quality of all systematic reviews relevant to the practice of nephrology published in 2005.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We searched electronic databases (Medline, Embase, American College of Physicians Journal Club, Cochrane) and hand searched Cochrane renal group records. Clinical practice guidelines, case reports, narrative reviews, and pooled individual patient data meta-analyses were excluded. Methodologic quality was measured using a validated questionnaire (Overview Quality Assessment Questionnaire). For reviews of randomized trials, we also evaluated adherence to recommended reporting guidelines (Quality of Reporting of Meta-Analyses).

RESULTS

Ninety renal systematic reviews were published in year 2005, 60 of which focused on therapy. Many systematic reviews (54%) had major methodologic flaws. The most common review flaws were failure to assess the methodologic quality of included primary studies and failure to minimize bias in study inclusion. Only 2% of reviews of randomized trials fully adhered to reporting guidelines. A minority of journals (four of 48) endorsed adherence to consensus guidelines for review reporting, and these journals published systematic reviews of higher methodologic quality (P < 0.001).

CONCLUSIONS

The majority of systematic reviews had major methodologic flaws. The majority of journals do not endorse consensus guidelines for review reporting in their instructions to authors; however, journals that recommended such adherence published systemic reviews of higher methodologic quality.

Noninvasive Hemodynamic Monitoring in the Intensive Care Unit

This article reviews the clinically available devices that have been approved for noninvasive hemodynamic monitoring in critically ill patients. In addition this article reviews some of the surrogate markers that can be used to assess adequacy of cardiac output.

The reno-protective effect of hydration with sodium bicarbonate plus N-acetylcysteine in patients undergoing emergency percutaneous coronary intervention: the RENO Study

OBJECTIVES

This study was designed to determine the effectiveness of a protocol for rapid intravenous hydration to prevent contrast-induced nephropathy (CIN) in patients undergoing emergency percutaneous coronary intervention (PCI).

BACKGROUND

Contrast-induced nephropathy frequently complicates PCI, resulting in prolonged hospitalization and increased in-hospital and long-term morbidity and mortality. Little is known regarding prevention of CIN in patients undergoing urgent PCI.

METHODS

We conducted a prospective, controlled, randomized, single-center trial in 111 consecutive patients with acute coronary syndrome undergoing emergency PCI. As part of the hydration therapy, 56 patients (group A) received an infusion of sodium bicarbonate plus N-acetylcysteine (N-AC) started just before contrast injection and continued for 12 h after PCI. The remaining 55 patients (group B) received the standard hydration protocol consisting of intravenous isotonic saline for 12 h after PCI. In both groups, 2 doses of oral N-AC were administered the next day.

RESULTS

The 2 groups were similar with respect to age, gender, diabetes mellitus, and baseline serum creatinine. A serum creatinine concentration >0.5 mg/dl from baseline after emergency PCI was observed in 1 patient in group A (1.8%) and in 12 patients in group B (21.8%; p < 0.001). Acute anuric renal failure was observed in 1 patient (1.8%) in group A and in 7 patients (12.7%) in group B (p = 0.032).

CONCLUSIONS

Rapid intravenous hydration with sodium bicarbonate plus N-AC before contrast injection is effective and safe in the prevention of CIN in patients undergoing emergency PCI.

Facts and fallacies concerning the prevention of contrast medium-induced nephropathy

OBJECTIVE

The aim of this article is to extract from recent medical literature and nephrologic practice the facts and fallacies concerning the possible prophylaxis of contrast medium-induced nephropathy.

DATA SOURCES, STUDY SELECTION, AND DATA EXTRACTION

A MEDLINE/PubMed search (1985 to January 2006) was conducted, including all relevant articles investigating the pathogenesis and prevention of contrast medium-induced nephropathy from a nephrologic critical point of view.

DATA SYNTHESIS

Considerable efforts have been made to develop pharmacologic therapy for the prevention of contrast medium-induced nephropathy, especially in patients at risk, such as elderly subjects and those with preexisting renal impairment, hypovolemia, or dehydration. There is general consensus that hydration protocols implemented before and after imaging with contrast medium may be effective in preventing contrast medium-induced nephropathy. However, definitive and convincing data related to amounts to be infused, infusion timing, and type of solutions (half-isotonic, isotonic saline solution, or bicarbonate) are lacking. Forced diuresis with furosemide or mannitol and use of dopamine, together with concomitant hydration, have been proved to be ineffective or even more risky in the event of inadequate maintenance of euvolemia. Various direct or indirect vasodilators have been investigated (atrial natriuretic peptide, calcium channel blockers, angiotensin-converting enzyme inhibitors, and endothelin receptor antagonists), yet results have been inconsistent and inconclusive. Recent large meta-analyses concerning the protective role of antioxidant action of N-acetylcysteine have led to the conclusion that the statistical significance of the results is borderline. Preventive hemodialysis has not proved to be useful; on the contrary, it might worsen the clinical conditions by inducing hypotension. Hemofiltration, despite some positive studies, is too complex and cannot be used extensively.

CONCLUSIONS

: It is believed that prevention is actually achieved by correcting hypovolemia, dehydration, or both. Normalization of body fluids is probably the true objective to be achieved by preventive measures in all patients, not only in those at risk. Because limited data have been collected in intensive care units, at present, no firm or specific recommendations can yet be provided for the critically ill.