[Show abstract][Hide abstract] ABSTRACT: Purpose:
To assess urinary tissue inhibitor of metalloproteinases-2 and insulin-like growth factor binding protein 7 ([TIMP-2]·[IGFBP7]), urinary neutrophil gelatinase-associated lipocalin (NGAL), and urinary cystatin-C as acute kidney injury predictors (AKI) exploring the association of nonrenal factors with elevated biomarker levels.
We studied 94 patients with urine collected within 48 hours of ICU admission and no AKI at sampling. AKI was defined by the Kidney Disease: Improving Global Outcomes criteria. Predictive performance was assessed by the area under the receiver operating characteristics (ROC) curve. Associations between biomarkers and clinical factors were assessed by multivariate linear regression.
Overall, 19 patients (20%) developed AKI within 48 hours. [TIMP-2]·[IGFBP7], NGAL, or cystatin-C admission levels did not differ between patients without AKI and patients developing AKI. [TIMP-2]·[IGFBP7], NGAL, and cystatin-C were poor AKI predictors (ROC areas 0.34-0.51). Diabetes was independently associated with higher [TIMP-2]·[IGFBP7] levels (P = 0.02) but AKI was not (P = 0.24). Sepsis was independently associated with higher NGAL (P < 0.001) and cystatin-C (P = 0.003) levels.
Urinary [TIMP-2]·[IGFBP7], NGAL, and cystatin-C should be used cautiously as AKI predictors in general ICU patients since urine levels of these biomarkers are affected by factors other than AKI and their performance can be poor.
[Show abstract][Hide abstract] ABSTRACT: Labile iron appears to play a role in the pathogenesis of acute kidney injury (AKI). Neutrophil gelatinase--associated lipocalin (NGAL) and hepcidin are involved in iron metabolism and are both upregulated during renal stress. However, in patients at risk, the highest levels of urinary NGAL are associated with AKI severity but the highest urinary hepcidin levels are associated with absence of AKI. We aimed to investigate the value of combining both biomarkers to estimate the severity and progression of AKI in ICU patients.
Urinary NGAL and hepcidin were quantified within 48 hours of ICU admission in critically ill patients with the systemic inflammatory response syndrome and early signs of kidney dysfunction (oliguria for ≥2 hours and/or a 25 μmol/L creatinine rise from baseline). Diagnostic and prognostic characteristics were assessed by logistic regression and receiver operating characteristics (ROC) analysis.
Of 102 patients, 26 had mild AKI and 28 patients had severe AKI on admission. Sepsis (21%), cardiac surgery (17%) and liver failure (9%) were the primary reasons for ICU admission. NGAL increased (P=0.03) whereas hepcidin decreased (P=0.01) with increasing AKI severity. The value of NGAL/hepcidin ratio to detect severe AKI was higher than when NGAL and hepcidin were used individually and persisted after adjusting for potential confounders (adjusted OR 2.40, 95% CI 1.20--4.78). The ROC areas for predicting worsening AKI were 0.50, 0.52 and 0.48 for NGAL, 1/hepcidin and the NGAL/hepcidin ratio, respectively.
The NGAL to hepcidin ratio is more strongly associated with severe AKI than the single biomarkers alone. NGAL and hepcidin, alone or combined as a ratio, were unable to predict progressive AKI in this selected ICU cohort.
[Show abstract][Hide abstract] ABSTRACT: Background
Measurement of high-sensitivity cardiac troponin levels is increasingly utilized in non ST-elevation acute coronary syndrome (NSTE-ACS). However, studies investigating the distribution and prognostic implications of high-sensitivity troponin levels in men and women separately are currently lacking.
Cardiac troponin I (cTnI) levels were determined using a high-sensitivity assay (Abbott Laboratories) in 1677 male and 1073 female NSTE-ACS patients participating in the GUSTO IV study. The prognostic associations of cTnI to outcome (30-day composite endpoint of recurrent myocardial infarction and 1-year mortality) were assessed in multivariable models, using cTnI both as a continuous variable and dichotomized at different sets of single and gender-specific 99th percentiles.
Median cTnI levels were 947 and 175 ng/L in men and women, respectively (p < 0.001). The adjusted odds ratios for cTnI (ln) were similar in men and women. The adjusted odds ratios for cTnI above the tested 99th percentiles levels in contrast, were twice as high in women compared to men. This was a consequence of differences in the cTnI distribution and risk gradients across cTnI levels, in particular due to lower event rates in women without cTnI elevation. Gender-specific cut-offs did not improve risk prediction.
Despite overall lower levels, cTnI above the tested 99th percentiles exhibited stronger prognostic information in women with NSTE-ACS compared to men. This likely reflects differences in the pathophysiology and the clinical presentation in NSTE-ACS. Our data thus, emphasize that women with symptoms of unstable coronary artery disease encompass a broader risk panorama than men.
American Heart Journal 09/2014; 168(3). DOI:10.1016/j.ahj.2014.06.006 · 4.46 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Knowledge on the contribution of protein glycosylation in host defense antimicrobial peptides is still scarce. We have studied here how the post-translational modification pattern modulates the antimicrobial activity of one of the best characterized leukocyte granule protein. The human Eosinophil Cationic Protein (ECP), an eosinophil specific granule protein secreted during inflammation and infection, can target a wide variety of pathogens. Previous work in human eosinophil extracts identified several ECP native forms and glycosylation heterogeneity was found to contribute to the protein biological properties. In this study we analyze for the first time the antimicrobial activity of the distinct native proteins purified from healthy donors blood. Low and heavy molecular weight forms were tested on E. coli cell cultures and compared with the recombinant non-glycosylated protein. Further analysis on model membranes provided an insight towards the understanding of the protein behavior at the cytoplasmic membrane level. The results highlight the significant reduction in the protein toxicity and bacteria agglutination activity for heavy glycosylated fractions. Notwithstanding, the lower glycosylated fraction mostly retains the lipopolysaccharide binding affinity together with the cytoplasmic membrane depolarization and membrane leakage activities. From structural analysis we can propose that heavy glycosylation interferes with the protein self aggregation, hindering the cell agglutination and membrane disruption processes. The results suggest the contribution of post-translational modifications on the antimicrobial role of ECP in host defense.This article is protected by copyright. All rights reserved.
[Show abstract][Hide abstract] ABSTRACT: Background:
Late enhancement MRI (LE-MRI) and cardiac troponin I (cTnI) are sensitive methods to detect subclinical myocardial injury. We sought to investigate the relation between plasma concentrations of cTnI measured with a high-sensitivity assay (hs-cTnI) and the development of unrecognized myocardial infarctions (UMIs) detected with LE-MRI.
After approval from the ethics committee and written informed consent were obtained, LE-MRI was performed on 248 randomly selected community-living 70-year-old volunteers and hs-cTnI was determined with a highly sensitive premarket assay. Five years later these individuals were invited to a second LE-MRI, and 176 of them (82 women, 94 men), who did not have a hospital diagnosis of MI, constitute the present study population. LE-MR images were analyzed by 2 radiologists independently and in a consensus reading, blinded to any information on previous disease or assessments.
New or larger UMIs were detected in 37 participants during follow-up. Plasma concentrations of hs-cTnI at 70 years of age, which were mainly within what is considered to be the reference interval, were related to new or larger UMIs at 75 years of age with an odds ratio of 1.98 per 1 unit increase in ln-transformed cTnI (95% CI, 1.17-3.35; P = 0.010). Plasma concentrations of hs-cTnI at 70 years of age were associated with the volumes of the UMIs detected at 75 years of age (P = 0.028).
hs-cTnI in 70-year-old community-living women and men was associated with the development of MRI-detected UMIs within 5 years.
[Show abstract][Hide abstract] ABSTRACT: Previous studies showed that the biological activity and the eosinophil content of eosinophil cationic protein (ECP, RNase 3) are determined by single-nucleotide polymorphisms (SNPs) in the ECP (RNase3) gene. In this study, we report the prevalence of a common SNP in the eosinophil protein x/eosinophil-derived neurotoxin (EPX/EDN, RNase2) and the association with the cellular contents of EPX/EDN and ECP. The genes were sequenced and the EPX/EDN405(G>C) rs2013109 SNPs were also determined by TaqMan 5′nuclease allelic discrimination assay. ECP and EPX/EDN in purified eosinophils or in whole blood extracts were analysed by sensitive immunoassays. The study included 379 non-allergic and allergic subjects. The genotype prevalence of the EPX/EDN405(G>C) polymorphism was GG 59%, GC 36% and CC 6%. The cellular contents of ECP and EPX/EDN were related in a reciprocal fashion with the sums of the protein contents being constant. The contents were associated with the ECP562(G>C) rs2233860 and EPX/EDN405(G>C) gene polymorphisms. The cellular content of eosinophil peroxidase (EPO) was not associated with the ECP and EPX/EDN genotypes. The prevalence of the EPX/EDN405(G>C) genotypes and the contents of the proteins were similar in non-allergic and allergic subjects. The production and storage of the two ancestral proteins, ECP and EPX/EDN likely share common regulatory mechanisms, which result in opposing productions of the two proteins.
[Show abstract][Hide abstract] ABSTRACT: Background:
Cardiac troponins (cTnI and cTnT) are the recommended biomarkers of myocardial infarction. As cTn-specific autoantibodies (cTnAAb) can interfere with the cTn detection by state-of-the-art cTnI assays, our objective was to develop a sensitive cTnI immunoassay free from this analytical interference.
The assay used antibody-coated spots containing three capture Mabs/Fabs directed against the N-terminus, midfragment and C-terminus of cTnI and a europium chelate-labeled tracer Mab against the C-terminus. Following a 3-h sample incubation and washing, cTnI was quantified by time-resolved fluorometry.
The limit of detection (LoD) was 2.9 ng/L and the assay was linear up to 50,000 ng/L. The total precision of 10% CV was not reached, but 20% CV was reached at 10 ng/L. Mean cTnI (10-50,000 ng/L) recoveries were 100% and 119% in three cTnAAb-positive and two cTnAAb-negative individuals, respectively, verifying the interference resistance of the antibody design used. On average, Architect hs-cTnI assay gave seven-fold higher cTnI concentrations than the new assay but the correlation between the assays was good (r=0.958). Of apparently healthy individuals (n=159), 18% had measurable cTnI values (>LoD) and 10% were cTnAAb-positive. The proportion of measurable cTnI values, however, was significantly higher in cTnAAb-positive individuals (13/16, median cTnI 8.5 ng/L) than in cTnAAb-negative individuals (15/143, median cTnI <LoD) (p<0.001).
Although the developed sensitive cTnI assay without cTnAAb interference takes too long for diagnostic purposes, it could serve as an important analytical tool for exploring the impact of cTnAAbs for cTn testing and for unraveling the etiology behind cTn-related autoimmune responses.
Clinical Chemistry and Laboratory Medicine 03/2014; 52(7). DOI:10.1515/cclm-2013-1044 · 2.71 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The measurement of natriuretic peptides (NPs), B-type NP or N-terminal pro-B-type NP, can be an important tool in the diagnosis of acute heart failure in patients presenting to an Emergency Department (ED) with acute dyspnea, according to international guidelines. Studies and subsequent meta-analyses are mixed on the absolute value of routine NP assessment of ED patients. However, levels of NPs are likely to be used also to guide treatment and to assess risk of adverse outcomes in other patients at risk of developing heart failure, including those with pulmonary embolism or diabetes, or receiving chemotherapy. Natriuretic peptide levels, like other biomarkers, can now be measured at the point of care (POC). We have reviewed the current status of NP measurement together with the potential contribution of POC measurement of NPs to clinical care delivery in the emergency and other settings. Several POC systems for measuring NP levels are now available: these produce test results within 15 minutes and appear sufficiently sensitive and robust to be used routinely in diagnostic evaluations. Point-of-care systems could be used to assess NP levels in the ED and community outpatient settings to monitor the risk of acute heart failure. Furthermore, the use of protocol-driven POC testing of NP within the time frame of a patient consultation in the ED may facilitate and accelerate the throughput and disposition of at-risk patients. Appropriately designed clinical trials will be needed to confirm these potential benefits. It is also important that processes of care delivery are redesigned to take full advantage of the faster turnaround times provided by POC technology.
American heart journal 10/2013; 166(4):614-621.e1. DOI:10.1016/j.ahj.2013.06.012 · 4.46 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Objective:
Information is limited on the prognostic implications of cardiac troponin I (cTnI) changes during the first days of non-ST elevation acute coronary syndrome (NSTE-ACS).
High-sensitivity cTnI levels were measured at study inclusion and after 48 h in 1615 conservatively managed NSTE-ACS patients from the Global Use of Strategies To Open Occluded Coronary Arteries (GUSTO) IV trial.
Patients with moderately increased cTnI levels and without a relevant decrease over time had a significantly raised mortality at 30 days and 1 year. No relevant associations between cTnI changes and recurrent myocardial infarction were seen.
The cTnI change is predictive for subsequent mortality in selected conservatively managed NSTE-ACS patients.
[Show abstract][Hide abstract] ABSTRACT: We tested the hypothesis that activation of the innate immune response induces an imbalance in the proteolytic homeostasis in the peripheral airways of healthy subjects, towards excess serine or gelatinase proteinase activity. During bronchoscopy, 18 healthy human subjects underwent intra-bronchial exposure to endotoxin and contra-lateral exposure to vehicle. Bronchoalveolar lavage (BAL) samples were harvested 24 or 48 hours (h) later. We quantified archetype proteinases, anti-proteinases, inflammatory BAL cells, and, importantly, total plus net proteinase activities using functional substrate assays. As expected, endotoxin exposure increased the concentrations of polymorphonuclear leukocytes (PMN's) and macrophages, of proteinases and the anti-proteinases tissue inhibitor of metalloproteinase-1, α-1-antitrypsin and, to a lesser extent, secretory leukoproteinase inhibitor, at both time points. Notably, at these time points, endotoxin exposure substantially increased the quantitative NE/SLPI ratio and the net serine proteinase activity corresponding to neutrophil elastase (NE). Endotoxin exposure also increased the total gelatinase activity corresponding to matrix metalloproteinase (MMP)-9; an activity dominating over that of MMP-2. However, endotoxin exposure had no impact on net gelatinolytic activity at 24 or 48 h after exposure. Thus, local activation of the innate immune response induces an imbalance towards increased net serine proteinase activity in the proteolytic homeostasis of the peripheral airways in healthy subjects. Hypothetically, this serine proteinase activity can contribute to tissue remodelling and hypersecretion via NE from PMN's, if it is triggered repeatedly, as might be the case in chronic inflammatory airway disorders.
PLoS ONE 09/2013; 8(9):e75032. DOI:10.1371/journal.pone.0075032 · 3.23 Impact Factor