Prediction of pneumoconiosis by serum and urinary biomarkers in workers exposed to asbestos-contaminated minerals.

Workers processing nephrite, antigorite, or talc may be exposed to paragenetic asbestos minerals. An effective screening method for pneumoconiosis in workers exposed to asbestos-contaminated minerals is still lacking. The objective of this study was to assess the diagnostic accuracy of serum and urinary biomarkers for pneumoconiosis in workers exposed to asbestos-contaminated minerals. We conducted a case-control study in a cohort of stone craft workers in Hualien, where asbestos, nephrite, antigorite, and talc are produced. A total of 140 subjects were screened between March 2013 and July 2014. All subjects received a questionnaire survey and a health examination that included a physical examination; chest X-ray; and tests for standard pulmonary function, fractional exhaled nitric oxide, serum soluble mesothelin-related peptide (SMRP), fibulin-3, carcinoembryonic antigen (CEA), and urinary 8-Oxo-2'-deoxyguanosine (8-OHdG)/creatinine. After excluding subjects with uraemia and chronic obstructive pulmonary disease (COPD), we included 48 subjects with pneumoconiosis and 90 control subjects without pneumoconiosis for analysis. In terms of occupational history, 43/48 (90%) case subjects and 68% (61/90) of the control subjects had processed asbestos-contaminated minerals, including nephrite, antigorite, and talc. The case group had decreased pulmonary function in forced vital capacity (FVC), forced expiratory volume in one second, and forced expiratory flow between 25% and 75% of the FVC. The levels of SMRP, fibulin-3, urinary 8-OHdG/creatinine, and CEA were higher in the case group than in the control group. Subjects exposed to nephrite had significantly higher SMRP levels (0.84 ± 0.52 nM) than subjects exposed to other types of minerals (0.60 ± 0.30 nM). A dose-response relationship was observed between the SMRP level and the severity of pneumoconiosis. Machine learning algorithms, including variables of sex, age, SMRP, fibulin-3, CEA, and 8-OHdG/creatinine, can predict pneumoconiosis with high accuracy. The areas under the receiver operating characteristic curves ranged from 0.7 to 1.0. We suggest that SMRP and fibulin-3 could be used as biomarkers of pneumoconiosis in workers exposed to asbestos-contaminated minerals.

Urine Angiotensin II Signature Proteins as Markers of Fibrosis in Kidney Transplant Recipients.

BACKGROUND: Interstitial fibrosis/tubular atrophy (IFTA) is an important cause of kidney allograft loss; however, noninvasive markers to identify IFTA or guide antifibrotic therapy are lacking. Using angiotensin II (AngII) as the prototypical inducer of IFTA, we previously identified 83 AngII-regulated proteins in vitro. We developed mass spectrometry-based assays for quantification of 6 AngII signature proteins (bone marrow stromal cell antigen 1, glutamine synthetase [GLNA], laminin subunit beta-2, lysophospholipase I, ras homolog family member B, and thrombospondin-I [TSP1]) and hypothesized that their urine excretion will correlate with IFTA in kidney transplant patients. METHODS: Urine excretion of 6 AngII-regulated proteins was quantified using selected reaction monitoring and normalized by urine creatinine. Immunohistochemistry was used to assess protein expression of TSP1 and GLNA in kidney biopsies. RESULTS: The urine excretion rates of AngII-regulated proteins were found to be increased in 15 kidney transplant recipients with IFTA compared with 20 matched controls with no IFTA (mean log2[fmol/µmol of creatinine], bone marrow stromal cell antigen 1: 3.8 versus 3.0, P = 0.03; GLNA: 1.2 versus -0.4, P = 0.03; laminin subunit beta-2: 6.1 versus 5.4, P = 0.06; lysophospholipase I: 2.1 versus 0.6, P = 0.002; ras homolog family member B: 1.2 versus -0.1, P = 0.006; TSP1_GGV: 2.5 versus 1.9; P = 0.15; and TSP1_TIV: 2.0 versus 0.6, P = 0.0006). Receiver operating characteristic curve analysis demonstrated an area under the curve = 0.86 for the ability of urine AngII signature proteins to discriminate IFTA from controls. Urine excretion of AngII signature proteins correlated strongly with chronic IFTA and total inflammation. In a separate cohort of 19 kidney transplant recipients, the urine excretion of these 6 proteins was significantly lower following therapy with AngII inhibitors (P < 0.05). CONCLUSIONS: AngII-regulated proteins may represent markers of IFTA and guide antifibrotic therapies.

Urinary levels of the leukocyte surface molecule CD11b associate with glomerular inflammation in lupus nephritis.

Noninvasive biomarkers of disease activity are needed to monitor response to therapy and predict disease recurrence in patients with glomerulonephritis. The leukocyte surface markers integrin Mac-1 and CD16b have been implicated in the pathogenesis of lupus nephritis (LN). Mac-1 comprises a unique α subunit (CD11b) complexed with a common ß2 subunit, which are released along with CD16b from specific leukocyte subsets under inflammatory conditions including glomerulonephritis. We investigated the association of urinary CD11b and CD16b with histopathological activity in 272 patients with biopsy-proven glomerular diseases, including 118 with LN. Urine CD11b and CD16b were measured via enzyme-linked immunosorbent assay. Urinary levels of both markers were increased in LN, but only urinary CD11b was correlated with the number of glomerular leukocytes and with overall histopathological activity. In a subset of patients with samples available from the time of biopsy and subsequent clinical remission of LN, urinary levels of CD11b decreased with successful glucocorticoid treatment. Receiver-operating characteristic curve analysis demonstrated that urinary CD11b was superior to CD16b, the scavenger receptor CD163, and monocyte chemotactic protein-1 for the prediction of proliferative LN. In anti-mouse nephrotoxic serum glomerulonephritis, urinary CD11b correlated with histologic damage and decreased with corticosteroid treatment. In vitro, CD11b levels were decreased on activated mouse neutrophils displaying Fcγ receptor clustering and transendothelial migration, suggesting that leukocyte activation and transmigration are required for CD11b shedding in urine. Together, our results suggest that urinary CD11b may be a useful biomarker to estimate histopathological activity, particularly glomerular leukocyte accumulation, in LN.

Urinary biomarkers predict advanced acute kidney injury after cardiovascular surgery.

BACKGROUND: Acute kidney injury (AKI) after cardiovascular surgery is a serious complication. Little is known about the ability of novel biomarkers in combination with clinical risk scores for prediction of advanced AKI. METHODS: In this prospectively conducted multicenter study, urine samples were collected from 149 adults at 0, 3, 6, 12 and 24 h after cardiovascular surgery. We measured urinary hemojuvelin (uHJV), kidney injury molecule-1 (uKIM-1), neutrophil gelatinase-associated lipocalin (uNGAL), α-glutathione S-transferase (uα-GST) and π-glutathione S-transferase (uπ-GST). The primary outcome was advanced AKI, under the definition of Kidney Disease: Improving Global Outcomes (KDIGO) stage 2, 3 and composite outcomes were KDIGO stage 2, 3 or 90-day mortality after hospital discharge. RESULTS: Patients with advanced AKI had significantly higher levels of uHJV and uKIM-1 at 3, 6 and 12 h after surgery. When normalized by urinary creatinine level, uKIM-1 in combination with uHJV at 3 h post-surgery had a high predictive ability for advanced AKI and composite outcome (AUC = 0.898 and 0.905, respectively). The combination of this biomarker panel (normalized uKIM-1, uHJV at 3 h post-operation) and Liano's score was superior in predicting advanced AKI (AUC = 0.931, category-free net reclassification improvement of 1.149, and p <  0.001). CONCLUSIONS: When added to Liano's score, normalized uHJV and uKIM-1 levels at 3 h after cardiovascular surgery enhanced the identification of patients at higher risk of progression to advanced AKI and composite outcomes.

Hemojuvelin Predicts Acute Kidney Injury and Poor Outcomes Following Cardiac Surgery.

Acute kidney injury (AKI) is detrimental after cardiac surgery. In this multicenter study, the novel biomarker hemojuvelin (HJV) was evaluated for AKI prediction following cardiac surgery. Urinary HJV, neutrophil gelatinase-associated lipocalin (NGAL), and urinary creatinine were measured in 151 patients after surgery. The outcomes of advanced AKI (KDIGO stages 2 and 3) and all causes of in-hospital mortality as the composite outcome were recorded. Areas under the receiver operator characteristic curves (AUC) and a multivariate generalized additive model (GAM) were applied to predict these outcomes of interest. Urinary HJV differentiated patients with/without AKI, advanced AKI or composite outcome after surgery (p < 0.001, by a generalized estimating equation) in this study. At three hours post-surgery, urinary HJV predicted advanced AKI (p < 0.001) and composite outcome (p < 0.001) with corresponding AUC values of 0.768 and 0.828, respectively. The performance of creatinine-adjusted HJV was also superior to NGAL in predicting advanced AKI (AUC = 0.784 and 0.694; p = 0.037) and composite outcome (AUC = 0.842 and 0.676; p = 0.002). The integration of HJV into the Cleveland Clinic score for advanced AKI led to a significant increase in risk stratification (net reclassification improvement [NRI] = 0.598; p < 0.001).

Biomarkers for Chronic Kidney Disease Associated with High Salt Intake.

High salt intake has been related to the development to chronic kidney disease (CKD) as well as hypertension. In its early stages, symptoms of CKD are usually not apparent, especially those that are induced in a "silent" manner in normotensive individuals, thereby providing a need for some kind of urinary biomarker to detect injury at an early stage. Because traditional renal biomarkers such as serum creatinine are insensitive, it is difficult to detect kidney injury induced by a high-salt diet, especially in normotensive individuals. Recently, several new biomarkers for damage of renal tubular epithelia such as neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 (Kim-1) have been identified. Previously, we found a novel renal biomarker, urinary vanin-1, in several animal models with renal tubular injury. However, there are few studies about early biomarkers of the progression to CKD associated with a high-salt diet. This review presents some new insights about these novel biomarkers for CKD in normotensives and hypertensives under a high salt intake. Interestingly, our recent reports using spontaneously hypertensive rats (SHR) and normotensive Wistar Kyoto rats (WKY) fed a high-salt diet revealed that urinary vanin-1 and NGAL are earlier biomarkers of renal tubular damage in SHR and WKY, whereas urinary Kim-1 is only useful as a biomarker of salt-induced renal injury in SHR. Clinical studies will be needed to clarify these findings.

Early prediction of cisplatin-induced nephrotoxicity by urinary vanin-1 in patients with urothelial carcinoma.

Cisplatin is a widely used anticancer drug, but its nephrotoxicity is a serious problem. To examine whether the novel biomarker, urinary vanin-1, could predict reduction in renal function after dosing of cisplatin. We conducted a prospective single-center pilot study of 24 patients with urothelial carcinoma who received cisplatin-based chemotherapy between 2012 and 2015. The primary outcome was a 20% or greater decline in estimated glomerular filtration rate (eGFR) from baseline within the first 6days of cisplatin. Urine concentration of creatinine, kidney injury molecule-1 (KIM-1), neutrophil gelatinase-associated lipocalin (NGAL) and NAG (N-acetyl-ß-d-glucosaminidase) as well as vanin-1 were measured during the perioperative period. During 6days after cisplatin, 37.5% (9/24) of patients showed more than 20% decline in eGFR (baseline, 68.8±11.1mL/min/1.73m(2); on day 6, 51.0±2.5mL/min/1.73m(2)) and this reduction persisted until day 10. Urinary vanin-1, but not KIM-1, NGAL and NAG, significantly elevated early on day 3 after cisplatin, which preceded the elevation of serum creatinine on day 6. Sensitivity and specificity of a cutoff point of urinary vanin-1 (9.31ng/mg Cr) on day 3 were calculated to be 66.7% (95% CI: 0.30-0.93) and 83.3% (95% CI: 0.52-0.97), respectively, for predicting 20% decline in eGFR during 6days after cisplatin. These data suggest that urinary vanin-1 is an early predictive biomarker for decline in eGFR in patients with urothelial carcinoma after dosing of cisplatin.

Early urinary biomarkers for renal tubular damage in spontaneously hypertensive rats on a high salt intake.

A high salt intake exacerbates hypertension and accelerates renal tubular damage in hypertensive patients. However, data concerning early biomarkers for renal tubular change induced by a high salt intake are limited. The objective of this study was to clarify the time course of new biomarkers for renal tubular damage during high salt intake in spontaneously hypertensive rats (SHR). Male SHR received a regular or high-salt diet from 9 to 17 weeks of age. At 10 weeks of age, a high salt intake caused renal tubular damage, which was further exacerbated at 17 weeks of age. Although albuminuria was detected in salt-loaded SHR at 14 weeks of age, urinary excretion of vanin-1 and neutrophil gelatinase-associated lipocalin (NGAL) was elevated in these animals from 10-17 weeks of age. However, kidney injury molecule-1 (Kim-1) was elevated at 15 weeks of age in salt-loaded SHR. These results suggest that urinary vanin-1 and NGAL are potentially early biomarkers for renal tubular damage in SHR under a high salt intake.

Effectiveness of mesothelin family proteins and osteopontin for malignant mesothelioma.

Malignant mesothelioma (MM) is an aggressive tumour with poor prognosis whose early diagnosis is difficult. Mesothelin, megakaryocyte potentiating factor (MPF) and osteopontin have attracted attention as biomarkers. The aim of the present review is to provide an overview regarding these candidate biomarkers for MM, and discuss their potential role in today's clinical practice. Mesothelin and MPF have good specificity but sub-optimal sensitivity for detection of MM, being negative both in the sarcomatoid histological sub-type and in almost half of epithelioid mesothelioma, especially in the early stages. Osteopontin is a marker of the duration of asbestos exposure, but lacks specificity for mesothelioma. Several patient characteristics influence the diagnostic accuracy of biomarkers and make the establishment of the "optimal" diagnostic threshold difficult. Mesothelin and MPF have proved useful in assessing response to treatment. Combining different markers together may lead to an improvement in diagnostic accuracy, but there is still need for research in this area. Extensive validation and further research is required to improve the use of serum markers in mesothelioma management. In the near future, their application in clinical practice is probably in monitoring response to therapy, rather than in guiding diagnostic decisions and risk assessment of asbestos-exposed populations.

Mesothelin levels in urine are affected by glomerular leakage and tubular reabsorption.

BACKGROUND: Mesothelin is a soluble biomarker of malignant mesothelioma. Levels in serum, however, are also influenced by other factors, including age and glomerular filtration rate (GFR). The measurement of mesothelin in urine has recently gained interest, but the renal handling of this protein has not been sufficiently examined. PATIENTS AND METHODS: A total of 75 patients with benign kidney disease were prospectively included in the study. Mesothelin levels were measured in the serum and in the urine of all the participants by using enzyme-linked immunosorbent assay. Urinary albumin and alpha 1-microglobulin (A1M) levels, which are markers of glomerular leakage and of decreased tubular reabsorption, respectively, and the estimated GFR (eGFR) of each participant were obtained. All urine analyte levels were standardized (std) against urinary creatinine levels. RESULTS: Absolute mesothelin levels in urine (median, 0.58 nmol/L; interquartile range [IQR], 0.25-1.03 nmol/L) were significantly lower than those in serum (median, 1.74 nmol/L; IQR, 1.35-2.43 nmol/L; P < .001). Urinary mesothelin(std) levels positively correlated with serum mesothelin (r = 0.35, P < .01), albumin(std) (r = 0.51, P < .001), and A1M(std) levels (r = 0.71, P < .001). Neither age nor eGFR were associated with urinary mesothelin(std) levels. Similarly, multiple linear regression analysis indicated that only albumin(std) and A1M(std) levels were significantly positively associated with the urinary mesothelin(std) levels (adjusted R(2) = 0.49). CONCLUSION: Mesothelin levels in urine are affected by impaired glomerular and tubular function, which can influence the interpretation of mesothelin measurements and might cause false-positive results. These effects need to be accounted for to improve the further validation and possible clinical use of urinary mesothelin.

Urinary vanin-1 as a novel biomarker for early detection of drug-induced acute kidney injury.

Drug-induced nephrotoxicity is a serious problem in patients with hospital-acquired acute kidney injury (AKI). A new renal biomarker is needed because traditional markers are not sensitive for early detection of drug-induced AKI. In a recent study, we demonstrated that vanin-1 is a novel candidate biomarker of nephrotoxicant-induced kidney injury. The objective of the present study is to determine whether the increase in urinary vanin-1 is detected before the elevations of serum creatinine or urinary N-acetyl-ß-glucosaminidase (NAG), kidney injury molecule-1 (Kim-1), and neutrophil gelatinase-associated lipocalin (NGAL) in the two well established animal models of drug-induced AKI. After the administration of a higher dose of cisplatin (10 mg/kg, a single intraperitoneal dose) or gentamicin (120 mg/kg per day, once daily intraperitoneal dose for 9 days), urinary vanin-1 was detected earlier than the other biomarkers. In rats treated with a lower dose of cisplatin (5 mg/kg, a single intraperitoneal dose) or gentamicin (40 mg/kg per day, once daily intraperitoneal dose for 9 days), serum creatinine and urinary NAG were not changed throughout the study period, whereas urinary vanin-1, Kim-1, and NGAL were significantly increased. The renal vanin-1 protein levels were significantly decreased in rats treated with the higher dose of cisplatin on day 5 and gentamicin on day 9, and the immunofluorescence analyses confirmed that vanin-1 immunoreactivity in tubular cells was reduced with the time after the dose of cisplatin, indicating that urinary vanin-1 was leaked from tubular cells. These results suggest that, compared with urinary Kim-1 and NGAL, urinary vanin-1 is an earlier and equally sensitive biomarker for drug-induced AKI.

Mesothelin and kidney function--analysis of relationship and implications for mesothelioma screening.

PURPOSE: Malignant mesothelioma (MM) carries a poor prognosis and remains a major public health issue in many countries. Outcomes may be improved with earlier detection and this justifies screening the at-risk asbestos-exposed population. Soluble mesothelin is a potential biomarker for MM, but it has been observed to be elevated in patients with reduced kidney function. Defining the relationship between mesothelin concentrations and kidney function will allow more accurate interpretation of this assay. MATERIALS AND METHODS: A cross-sectional study consisting of 144 patients with chronic kidney disease (CKD) was conducted at Sir Charles Gairdner Hospital and Royal Perth Hospital in Western Australia. Only patients with CKD stages II-V were recruited while those with a history of renal transplant, dialysis, or malignancy were excluded. Serum and urine mesothelin and creatinine concentrations were determined. RESULTS: There were 33, 49, 31 and 31 patients in CKD stages II, III, IV and V, respectively recruited. Serum mesothelin increased significantly with increasing serum creatinine (p<0.0001), and worsening stage of CKD (p<0.0001). A significant correlation between urine mesothelin to creatinine ratio and serum mesothelin concentration was detected (p=0.002). No significant difference was found in urine mesothelin to creatinine ratios across the four CKD stage groups. CONCLUSION: Serum mesothelin concentration is elevated in individuals with renal impairment. Renal function should therefore be taken into account during interpretation of this assay.

Sensitivity of urinary mesothelin in patients with malignant mesothelioma.

INTRODUCTION: Malignant mesothelioma (MM) is an aggressive, uniformly fatal tumor usually caused by exposure to asbestos. Soluble mesothelin has been intensively investigated in the serum as a biomarker for this disease. As urine is less complex and less invasive to collect than serum and may be a more acceptable specimen for large-scale screening studies of asbestos-exposed individuals, we determined whether the sensitivity and specificity for MM could be improved by measuring soluble mesothelin in the urine. METHODS: Soluble mesothelin concentrations were determined using the MESOMARK assay in concurrent serum and urine samples from 70 patients with pleural MM, 111 patients with asbestos-related lung or pleural disease, and 45 patients with benign nonasbestos-related lung and pleural disease. Only patients with serum creatinine levels within the normal range were included in the study. Sensitivities were determined and receiver operator characteristic curves were generated to compare the diagnostic accuracy of mesothelin in the serum and urine. RESULTS: At a specificity of 95% relative to individuals with benign lung or pleural disease, serum mesothelin had a sensitivity of 66% and area under the curve of 0.882, whereas urinary mesothelin corrected for urine creatinine concentration had a sensitivity of 53% and area under the curve of 0.787. CONCLUSIONS: The sensitivity of urinary mesothelin does not warrant the use of urine as a biomarker specimen for MM diagnosis.