Coronary Intervention In The Incidence Of Cin Urine Marker Proteins In The Diagnosis And Treatment Of Acute Kidney Injury After The Screening And Diagnostic Prediction Model

Contrast-induced nephropathy(CIN) was defined as an absolute or relative increasein serum creatinine compared to the baseline values after the exposure to contrast agentwith the exclusion of alternative explanations for renal impairment.The increasing application of contrast media(CM) in diagnostic and interventionalprocedures results in the rising incidence of iatrogenic acute kidney injury caused by theexposure to CM. Radiographic CM are the third most common cause of renal failureafter impaired renal perfusion and the use of nephrotoxic medications. Earlyrecognition of CIN is the premise and the key point of early intervention. Butbiomarkers for early diagnosis of CIN is in deficiency.High throughput genomics and proteomics techniques have facilitated a betterunderstanding of diseases by deciphering the unique molecular signature that predictsclinical outcomes and therapeutics. The nascent field of proteomics—the completedescription of all the proteins encoded by the genome—promises to rapidly expand ourunderstanding of the occurrence of CIN. An important goal of clinical proteomics is todevelop robust, sensitive, and specific methodologies for the simultaneous analysis of allthe proteins expressed by the human genome, and to establish "bio-signature" profilesthat discriminate between disease states.One of these technological advances in proteomics is the surface-enhanced laserdesorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS). Applicationsof this technology have suggested great potential for the early detection of variousdisease. The objective of this study is to identify biomarkers indicative of prognosis inurine obtained from CIN subjects. Then a clinical diagnostic and proteomic predictivepattem on CIN is established and tested. Part One: Establishment of the platform of protein chip SELDI-TOF-MSThe objective of this part of research was to determine the best conditions forSELDI-TOF-MS platform. Urine samples from eight cases of patients were collectedrespectively. The mass-to-charge ratio (M/Z) of each of the proteins captured on the arraysurface was determined according to externally-calibrated standards (CiphergenBiosystems). Protein or peptide spectra were produced by SELDI-TOF-MS measurementafter testing the sample onto four types of Protein Chips. They were weak cationexchange (WCX) chip, strong anion exchange (SAX) chip, immobilized metal affinitycapture (IMAC) chip and hydrophobic surface (H4) chip. Through the protein profilingresults, proper parameters and protein chips were selected respectively, and the reliabilityand stability of the platform were evaluated.RESULTS:1. Most of the proteins detected by protein chip ranged from 1100 to 30000 at theM/Z value.2. These preliminary assays resulted in the selection of IMAC3 chip as the mosteffective chip array in detecting urine protein fingerprints.3. Of the same sample, the coefficient variation (CV) of protein intensity and M/Zvalue was 0.1928 and 0.000453 within the same protein chip4. The CV of protein intensity and M/Z value was 0.214244 and 0.000055 amongthe protein chips with the same sample.Part Two: The influence of low osmolar contrast media on renalfunction of patients undergoing percutaneous coronary interventions—A prospective studyThe objective of this study was to explore the influence of non-ionic low osmolarcontrast media on the renal function of patients undergoing percutaneous coronaryintervention(PCI) during which non-ionic low osmolar contrast media was used, toestimate the incidence of contrast-induced nephropathy (CIN) and its risk factors. From November 2005 to May 2006, 275 patients undergoing PCI were enrolled. CIN wasdefined as an increase of serum creatinine by 25% higher than the baseline value within48 hours upon contrast exposure. Serum creatinine, urine n-acetyl-β-d-glucosaminidase(NAG) and urine osmolarity were measured before PCI and after angiography and theinfluence of contrast media on patients' renal function was analyzed.Results:4. Of the 275 patients, 203 were male and 72 were female. The mean of patients' agewas 63.5±11.6 years. The incidence of CIN was 4%. There was no significantdifference on the incidence of CIN between the diabetics and non-diabetics5. Among the 264 non-CIN patients, urinary NAG in Day 1 after angiography wassignificantly higher than the baseline value (p＜0.05), but there was no significanceon the level of urinary NAG in Day 2 after angiography compared with the baselinevalue. As for the 11 CIN patients, urinary NAG in Day 1 and Day 2 afterangiography were both higher than the baseline values, but returned to the baselinevalue in Day 6 after angiography.6. The dosage of contrast medium was much more in CIN group(318.4±153.8ml)than in non-CIN group (227.9±121.9ml) (p＜0.01).Part Three: Screen urine biomarkers with relation to the occurrence ofcontrast-induced nephropathy following percutaneous coronaryintervention and establish the urine diagnostic and predictive proteomicpatternThe aim of this study was to appraise and compare protein expression profiles inurine of patients without or with contrast-induced nephropathy following percutaneouscoronary intervention, and therefore establish the urine diagnostic and predictiveproteomic pattern. Eleven CIN patients and 22 non-CIN patients were involved.Three freshly voided morningurine samples were studied for each patient. The first wasobtained before coronary intervention, the second was obtained the next moming aftercardiac catheterization, and the third was obtained the second day after coronaryintervention. Special urine protein or peptide spectra was determined bySELDI-TOF-MS measurement after treating the sample onto IMAC3 protein chip for each case. Spectra were analyzed with Ciphergen ProteinChip software (version 3.1)and normalized. Then intensity values for each peak were input into Biomarker PatternsSoftware for classification tree analysis and the best performing tree was chosen fortesting. Second, the randomly selected samples were categorized with the decision treebeing tested to ensure that the decision tree was valid.Results:1. There were no significant difference in age, sex, pre-catheterization cardiac functionbetween the groups of CIN and non-CIN. But the dosage of contrast medium wasmuch more in CIN group than in non-CIN group.2. Comparing urine protein fingerprints between the samples collected before coronaryintervention and after the procedure, a total of 36 protein peaks were identified at theM/Z value ranging from 2000 to 30000, 17 significant differential proteins werefound between the moming urine samples obtained before coronary intervention andthose obtained the first day after contrast adminstration (P＜0.05). Among 17significant differential proteins, 2 proteins were down regulated with the M/Z valueof 8896 and 9519 in post-catheterization group, 15 proteins were up regulated withthe M/Z value of 11943, 11762, 11707, 5889, 5320, 5995, 13393, 13322, 23537,14730, 13923, 14640, 7060, 3916 and 2801 respectively in post-catheterizationgroup.3. Comparing the the first morning urine sample after coronary intervention, a total of50 protein peaks were identified at the M/Z value ranging from 2000 to 30000, 13significant differential proteins were found between the CIN group and non-CINgroup. Among 13 significant differential proteins, 8 proteins were down regulatedwith M/Z value of 2794, 5505, 26043, 2195, 16919, 25759, 2440 and 20514 in CINgroup, 5 proteins were up regulated with M/Z value of 1797, 2092, 4357, 3913 and8195.4. In non-CIN group, on the second morning after coronary angiography, 2 proteinpeaks with M/Z value of 11734 and 5930 had a strong trend toward the recovery ofits precatheterization urinary protein pattem, which was not happened in CIN group.5. Urine protein profiles obtained from 11 CIN patients and 22 non-CIN patients weregenerated using classification trees by Biomarker Patterns Software, which was constituted by 2 candidate proteins with the M/Z value of 2793 and 2091, with asensitivity of 72.7% (8/11) and specificity of 81.82% (18/22).Part Four A Survey of acute kidney injury in hospitalized patientsThis study's objective was to determine the incidence of acute kidney injury amonghospitalized patients in a tertiary hospital, as well as the constitution of the causes, toassess the prognosis of AKI and evaluate the impact of AKI on hospital cost and length ofstay (LOS). Patients who were admitted in Zhongshan Hospital, Fudan Universityfrom September 1st 2004 to August 31st 2005 were involved. After checking thecomputer-based data on kidney function, patients with acute kidney injury were pickedout and further history reviews were demanded to get the information of patients' clinicalcharacteristics, prognosis, the severity of kidney injury and the causes of AKI.Results:1. There were 37365 admissions during the study period and 1228 met with thediagnostic criteria of acute kidney injury(AKI). The overall incidence rote of AKIwas 3.27%. In-hospital mortality was 1.52% in all discharges while 18.57% inpatients with AKI.2. The multivariable-adjust OR for death associated with AKI was 10.09 (p＜0.01).3. The results of logistic regression analysis suggested that old age, increased hospitalcost, nominal or percentage changes of serum creatinine were the risk factors ofdeath among AKI patients. Conclusions:1. Acute kidney injury is prevalent in hospitalized patients, a slight elevation of serumcreatinine is associated with significantly increased mortality, LOS and hospital cost.Patients' prognosis was related to the severity of kidney injury. The mortality rateincreased with the percentage changes in serum creatinine.2. The incidence of CIN following PCI is not very low. Acute kidney injury could beinduced by non-ionic low osmolar contrast media. Elevated urinary NAGrepresented renal tubular injury. Renal function could return to the baseline in Day6 after angiography for most patients while a small part of patients remained renalinsufficiency. A higher volume of CM was an independent risk factor for CIN inpatients undergoing PCI, who had no pre-exsiting kidney disease.3. Utilizing SELDI-TOF and the same bioinformatics software package is an idealtechnological platform for proteomic research. IMAC3 protein chip was suitable forthe research of urine proteomics in CIN. Quality control and standardization ofanalysis conditions could be key issue for the reliability of outcome.4. With the high-throughput proteomics technology combined with SELDI-TOF andprotein chip, differential displayed low molecular proteins found in the urine of CINpatients was of great importance in identifying the diagnostic urinary biomarker ofCIN and elucidating its pathogenesis. BPS-based decision tree classificationsshowed great advantages over conventional urinary biomarkers in the diagnosis andprognosis-prediction of CIN.NOVELTY1. Establishment of urinary protein fingerprints in CIN.2. Application of protein chips to elucidating the mechanism of CIN.3. Establishment of clinical urinary diagnostic and predictive proteomic pattern for CIN.4. The discriminated protein would supply us with more sensitive and specific index toselect CIN patients and well understand their prognosis. Screening of urinebiomarkers (protein) related to establishment of CIN, which may shed further lighton the field.