Tissue Inhibitor Metalloproteinase-2·IGF-Binding Protein 7 for the Prediction of Acute Kidney Injury following Cardiac Surgery.

INTRODUCTION: Cardiac surgery-associated acute kidney injury (CSA-AKI) is a common complication associated with increased morbidity and mortality. Tissue inhibitor metalloproteinase-2·insulin-like growth factor-binding protein 7 (TIMP-2·IGFBP7) determines tubular stress markers, which may occur prior to tubular damage. Previous studies on the use of TIMP-2·IGFBP7 for the prediction of CSA-AKI showed divergent results. Therefore, this study aimed to explore the predictive value of TIMP-2·IGFBP7 measurements for the early detection of acute kidney injury (AKI) and short-term adverse outcomes after cardiac surgery. METHODS: In the prospective cohort study, blood and urine samples were collected 6-12 h after cardiac surgery. Blood samples to monitor serum creatinine levels were additionally extracted from days 1 to 7. AKI was defined based on the KDIGO consensus guidelines. AKI within 7 days following surgery was the primary outcome. The initiation of renal replacement therapy, in intensive care unit mortality, and the combination of both were secondary outcomes. RESULTS: A total of 557 patients were enrolled; 134 (24.06%) of them developed AKI and 33 (5.9%) had moderate or severe AKI. AKI developed more frequently in elderly patients with diabetes or with higher baseline serum creatinine levels. Patients with AKI had higher EuroSCORE II, Cleveland Clinic Score, and simplified renal index (SRI) than those without AKI. Urinary TIMP-2·IGFBP7 was significantly higher in patients with AKI. The area under the curve was 0.66 in predicting all AKI and 0.70 in predicting stages 2 and 3 AKI. The resulting sensitivity and specificity were 44.0% and 83.9%, respectively, for a calculated threshold TIMP-2·IGFBP7 value of 0.265 (ng/mL)2/1,000. The TIMP-2·IGFBP7 values, SRI score, and age were significantly associated with AKI within 7 days postoperatively. A total of 33 patients reached the composite endpoint; the percentage of patients who reached the composite endpoint in the TIMP-2·IGFBP7 of >0.265 (ng/ml)2/1,000 group was significantly higher than that of ≤0.265 (ng/mL)2/1,000 group. CONCLUSIONS: Postoperative implementation of TIMP-2·IGFBP7 improved the prediction of CSA-AKI and may aid in identifying patients at risk of short-term adverse outcomes. We identified an ideal calculated cutoff value of 0.265 (ng/mL)2/1,000 for the prediction of CSA-AKI among all AKI patients.

Diagnostic accuracy of thermal, hydration, and heart rate assessments in discriminating positive acute kidney injury risk following physical work in the heat.

Occupational heat stress increases the risk of acute kidney injury (AKI). This study presents a secondary analysis to generate novel hypotheses for future studies by investigating the diagnostic accuracy of thermal, hydration, and heart rate assessments in discriminating positive AKI risk following physical work in the heat in unacclimatized individuals. Unacclimatized participants (n = 13, 3 women, age: ∼23 years) completed four trials involving 2 h of exercise in a 39.7 ± 0.6 °C, 32 ± 3% relative humidity environment that differed by experimental manipulation of hyperthermia (i.e., cooling intervention) and dehydration (i.e., water drinking). Diagnostic accuracy was assessed via receiver operating characteristic curve analysis. Positive AKI risk was identified when the product of concentrations insulin-like growth factor binding protein 7 and tissue inhibitor of metalloproteinase-2 [IGFBP7∙TIMP-2] exceeded 0.3 (ng∙mL-1)2∙1000-1. Peak absolute core temperature had the acceptable discriminatory ability (AUC = 0.71, p = 0.009), but a relatively large variance (AUC 95% CI: 0.57-0.86). Mean body temperature, urine specific gravity, urine osmolality, peak heart rate, and the peak percent of both maximum heart rate and heart rate reserve had poor discrimination (AUC = 0.66-0.69, p ≤ 0.051). Mean skin temperature, percent change in body mass and plasma volume, and serum sodium and osmolality had no discrimination (p ≥ 0.072). A peak increase in mean skin temperature of >4.7 °C had a positive likelihood ratio of 11.0 which suggests clinical significance. These data suggest that the absolute value of peak core temperature and the increase in mean skin temperature may be valuable to pursue in future studies as a biomarker for AKI risk in unacclimatized workers.

Evaluating TIMP-2 and IGFBP-7 as a predictive tool for kidney injury in ureteropelvic junction obstruction

ABSTRACT A major challenge in the management of ureteropelvic junction obstruction (UPJO) is the selection of patients who would benefit from surgical treatment. Tissue inhibitor metalloproteinase-2 (TIMP-2) and insulin-like growth factor-binding protein 7 (IGFBP7) indicate renal cell stress and are associated with cell cycle arrest. The [TIMP-2] [IGFBP7] ratio (Nephrocheck®) has been recently applied in patients in intensive care units patients to predict the development of acute kidney injury. In this study, we evaluated the performance of these biomarkers performance to distinguishing obstructive hydronephrosis (HN) from non-obstructive HN. Materials and Methods: Consecutive patients with UPJO were enrolled in this study. Urinary [TIMP-2] [IGFBP7] and clinical characteristics (hydronephrosis grade, differential renal function, and drainage half-time) were measured in the following groups: 26 children with obstructive HN at initial diagnosis (group 1A) and after six months of dismembered pyeloplasty (group 1B); 22 children with non-obstructive HN (group 2), and 26 children without any urinary tract condition, as the control group (group 3). Results: Comparing the initial samples, [TIMP-2] [IGFBP7] had higher levels in the HN groups and lower levels in the control group; however, no difference was observed between the HN groups (obstructive vs. non-obstructive). After six months of follow-up, patients who underwent dismembered pyeloplasty showed stability in the urinary concentration of [TIMP-2] [IGFBP7]. All patients with [TIMP-2] [IGFBP7] higher than 1.0 (ng/mL)2/1000 had diffuse cortical atrophy on ultrasonography. Conclusions: We showed that urinary levels of urinary [TIMP-2] [IGFBP7] are higher in children with HN than controls. Nephrocheck® is not reliable in predicting the need for surgical intervention for pediatric patients with UPJO.

[Advances in the clinical value of tissue inhibitors of metalloproteinase-2 and insulin-like growth factor binding protein 7 in sepsis associated-acute kidney injury].

Sepsis is an important cause of acute kidney injury (AKI). About 60% of sepsis patients will develop AKI. At present, the standard of clinical diagnosis of AKI is still based on the changes in serum creatinine and urine volume. Because of its lag in time, it may lead to delay in treatment and increase the mortality. To find a new biomarker similar to "troponin" for the diagnosis of AKI, and to achieve the early diagnosis and prevention of AKI, is of great significance to reduce the mortality of AKI. In recent years, it has been found that tissue inhibitors of metalloproteinase-2 (TIMP-2) and insulin-like growth factor-binding protein 7 (IGFBP7) can be used for early diagnosis of sepsis associated-acute kidney injury (SA-AKI). They also have important values in risk stratification, prognosis judgment, intervention and other aspects of SA-AKI. In this paper, the research progress of the application of TIMP-2 and IGFBP7 in SA-AKI is reviewed.

Evaluating TIMP-2 and IGFBP-7 as a predictive tool for kidney injury in ureteropelvic junction obstruction.

A major challenge in the management of ureteropelvic junction obstruction (UPJO) is the selection of patients who would benefit from surgical treatment. Tissue inhibitor metalloproteinase-2 (TIMP-2) and insulin-like growth factor-binding protein 7 (IGFBP7) indicate renal cell stress and are associated with cell cycle arrest. The [TIMP-2] [IGFBP7] ratio (Nephrocheck®) has been recently applied in patients in intensive care units patients to predict the development of acute kidney injury. In this study, we evaluated the performance of these biomarkers performance to distinguishing obstructive hydronephrosis (HN) from non-obstructive HN. MATERIALS AND METHODS: Consecutive patients with UPJO were enrolled in this study. Urinary [TIMP-2] [IGFBP7] and clinical characteristics (hydronephrosis grade, differential renal function, and drainage half-time) were measured in the following groups: 26 children with obstructive HN at initial diagnosis (group 1A) and after six months of dismembered pyeloplasty (group 1B); 22 children with non-obstructive HN (group 2), and 26 children without any urinary tract condition, as the control group (group 3). RESULTS: Comparing the initial samples, [TIMP-2] [IGFBP7] had higher levels in the HN groups and lower levels in the control group; however, no difference was observed between the HN groups (obstructive vs. non-obstructive). After six months of follow-up, patients who underwent dismembered pyeloplasty showed stability in the urinary concentration of [TIMP-2] [IGFBP7]. All patients with [TIMP-2] [IGFBP7] higher than 1.0 (ng/mL)2/1000 had diffuse cortical atrophy on ultrasonography. CONCLUSIONS: We showed that urinary levels of urinary [TIMP-2] [IGFBP7] are higher in children with HN than controls. Nephrocheck® is not reliable in predicting the need for surgical intervention for pediatric patients with UPJO.

Relationships between Circulating Matrix Metalloproteinases, Tissue Inhibitor TIMP-2, and Renal Function in Patients with Myocarditis.

INTRODUCTION: Under physiological conditions, the myocardial extracellular matrix (ECM) is maintained by matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs). However, changes in the balance between MMPs and TIMPs can lead to pathological remodeling of the ECM, which contributes to cardiovascular and kidney diseases. The aim of our study was to assess levels of MMPs and TIMP-2 in patients with myocarditis and their relationship to renal function. MATERIALS AND METHODS: Forty five patients with myocarditis who underwent CMR were included, comprising 11 with concurrent chronic kidney disease (CKD). Blood samples were obtained to assess serum levels of MMP-2, MMP-3, MMP-9, and TIMP-2. RESULTS: Serum MMP-2, MMP-3, and TIMP-2 levels negatively correlated with the ejection fraction in patients with myocarditis, while MMP-3 levels correlated with longitudinal deformation (p < 0.05). Serum MMP-2, MMP-3, and TIMP-2 levels also negatively correlated with renal function, as assessed by the estimated glomerular filtration rate (eGFR) (p < 0.05). Patients with myocarditis and concurrent CKD had higher levels of MMP-2 and TIMP-2 than those without kidney damage. CONCLUSIONS: (1) We demonstrated that MMP-2, MMP-3, and TIMP-2 concentrations were related to left-ventricular ejection fraction, and MMP-3 levels correlated with longitudinal deformation, indicating MMPs play an important role in the post-inflammatory remodeling of the myocardium. (2) A negative correlation between the eGFR and MMP-2, MMP-3, and TIMP-2 and a positive correlation between creatinine and MMP-3 levels indicate the role of MMPs and TIMP-2 in renal dysfunction.

Adhesion pathway proteins and risk of atrial fibrillation in the Multi-Ethnic Study of Atherosclerosis.

BACKGROUND: The cellular adhesion pathway has been suggested as playing an important role in the pathogenesis of atrial fibrillation (AF). However, prior studies that have investigated the role of adhesion pathway proteins in risk of AF have been limited in the number of proteins that were studied and in the ethnic and racial diversity of the study population. Therefore we aimed to study the associations of fifteen adhesion pathway proteins with incident AF in a large, diverse population. METHODS: Multi-Ethnic Study of Atherosclerosis participants from four races/ethnicities (n = 2504) with protein levels measured were followed for incident AF (n = 253). HGF protein was measured on Exam 1 samples (N = 6669; AF n = 851). Cox proportional hazards regression was used to assess the association of AF with 15 adhesion pathway proteins. Bonferroni correction was applied to account for multiple comparisons. RESULTS: After adjusting for potential confounding variables (age, sex, race/ethnicity, height, body mass index, systolic blood pressure, antihypertension therapy, diabetes status, current smoker, current alcohol use, and total and HDL cholesterol), and accounting for multiple testing (P < 0.05/15 = 0.0033), circulating levels of the following proteins were positively associated with a higher risk of AF: MMP-2 (HR per standard deviation increment, 1.27; 95% CI 1.11‒1.45), TIMP-2 (HR 1.28; 95% CI 1.12‒1.46), VCAM-1 (HR 1.32; 95% CI 1.16‒1.50), and SLPI (HR 1.22; 95% CI 1.07‒1.38). The association between proteins and AF did not differ by race/ethnicity. CONCLUSIONS: Circulating levels of MMP-2, TIMP-2, VCAM-1, and SLPI were positively associated with an increased risk of incident AF in a diverse population. Our findings suggest that adhesion pathway proteins may be important risk predictors of AF.

The effect of surgery on the levels of matrix metalloproteinases in patients with inguinal hernia.

Matrix metalloproteinases (MMPs) are associated with the alteration of extracellular matrix. The purpose of this study was to investigate how the levels of matrix metalloproteinases and their inhibitors - TIMPs are influenced by the presence of inguinal hernia as well as by its surgical treatment. The studied group consisted of 25 patients with inguinal hernia and 21 healthy controls for comparison. Two blood samples - before and after the treatment were collected from patients. Serum concentrations of MMPs and TIMPs were analysed by multiplex immunoassays. There was a difference in circulating levels of MMPs in patients before the surgery compared to healthy controls - the concentrations of MMP-2 and MMP-9 were significantly lower (p=0.026, p=0.018, respectively). After the surgery, the levels of MMPs, especially MMP-2 (p<0.0001), were significantly decreased in patients compared to the preoperative values, apart from MMP-9. On the contrary, MMP-9 showed significant increase after the surgery (p<0.0001). Circulation levels of TIMP-2 in patients were significantly decreased in comparison with controls (p=0.004), whereas levels of TIMP-1 were similar to controls. Both tested metalloproteinase inhibitors showed a significant decrease in detected levels (TIMP-1 p=0.0004; TIMP-2 p<0.0001) after the procedure compared to the preoperative values. The levels of MMPs, especially MMP-2 and MMP-9, and their inhibitors TIMP-1 and TIMP-2 are involved by the presence of inguinal hernia as well as are influenced by the surgery.

TT genotype of the MMP-9-1562C/T polymorphism may be a risk factor for thrombolytic therapy-induced hemorrhagic complications after acute ischemic stroke.

INTRODUCTION: Levels of matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) influence recombinant tissue plasminogen activator (rtPA) therapy response in patients with acute ischemic stroke (AIS). Serum levels of MMPs and TIMPs along with the expression of genes coding these proteins are related to the recovery and appearance of adverse effects (AE) after AIS. Consequently, it is important to explore whether polymorphisms in regulatory sequences of MMPs and TIMPs are associated with rtPA response in AIS patients. OBJECTIVES: To determine whether selected polymorphic variants within MMP-2, MMP-9, and TIMP-2 genes may influence rtPA therapy response with regard to outcomes in patients with AIS and the occurrence of AE. METHODS: Our study included 166 patients suffering AIS, treated with rtPA. Patients' recovery was estimated using the Modified Rankin Scale (mRS) 3 months after the AIS occurred. Favorable outcome was defined with scores 0-1 and poor outcome with scores 2-6. Genotyping was performed using real-time PCR (rs243866, rs243865, rs243864, rs2277698, and rs8179090) and PCR-RFLP (rs2285053, rs3918242) methods. Additionally, rtPA AE were followed during the hospitalization. RESULTS: There was no significant association between genotypes and alleles of selected polymorphisms and rtPA therapy response measured through the decrease of the mRS score in patients with AIS. Intracranial hemorrhage, as well as parenchymal hematoma type 2, was significantly more frequent in patients with TT genotype of the MMP-9-1562C/T polymorphism (p = 0.047, p = 0.011, respectively). Patients with intracranial hemorrhages after rtPA were significantly more likely to have the TT genotype of TIMP-2-303C/T polymorphism and the TT genotype of MMP-9-1562C/T polymorphism (p < 0.001). CONCLUSION: TT genotype of the MMP-9-1562C/T polymorphism may be a risk factor for rtPA-induced hemorrhagic complications after AIS.

Use of Biomarkers to Identify Acute Kidney Injury to Help Detect Sepsis in Patients With Infection.

OBJECTIVES: Although early recognition of sepsis is vital to improving outcomes, the diagnosis may be missed or delayed in many patients. Acute kidney injury is one of the most common organ failures in patients with sepsis but may not be apparent on presentation. Novel biomarkers for acute kidney injury might improve organ failure recognition and facilitate earlier sepsis care. DESIGN: Retrospective, international, Sapphire study. SETTING: Academic Medical Center. PATIENTS: Adults admitted to the ICU without evidence of acute kidney injury at time of enrollment. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We stratified patients enrolled in the Sapphire study into three groups-those with a clinical diagnosis of sepsis (n = 216), those with infection without sepsis (n = 120), and those without infection (n = 387) at enrollment. We then examined 30-day mortality stratified by acute kidney injury within each group. Finally, we determined the operating characteristics for kidney stress markers (tissue inhibitor of metalloproteinases-2) × (insulin-like growth factor binding protein 7) for prediction of acute kidney injury as a sepsis-defining organ failure in patients with infection without a clinical diagnosis of sepsis at enrollment. Combining all groups, 30-day mortality was 23% for patients who developed stage 2-3 acute kidney injury within the first 3 days compared with 14% without stage 2-3 acute kidney injury. However, this difference was greatest in the infection without sepsis group (34% vs 11%; odds ratio, 4.09; 95% CI, 1.53-11.12; p = 0.005). Using a (tissue inhibitor of metalloproteinases-2) × (insulin-like growth factor binding protein 7) cutoff of 2.0 units, 14 patients (11.7%), in the infection/no sepsis group, tested positive of which 10 (71.4%) developed stage 2-3 acute kidney injury. The positive test result occurred a median of 19 hours (interquartile range, 0.8-34.0 hr) before acute kidney injury manifested by serum creatinine or urine output. Similar results were obtained using a cutoff of 1.0 for any stage of acute kidney injury. CONCLUSIONS: Use of the urinary (tissue inhibitor of metalloproteinases-2) × (insulin-like growth factor binding protein 7) test could identify acute kidney injury in patients with infection, possibly helping to detect sepsis, nearly a day before acute kidney injury is apparent by clinical criteria.

The 'rejuvenating factor' TIMP-2 is detectable in human blood components for transfusion.

BACKGROUND AND OBJECTIVES: Tissue inhibitor of metalloproteinases 2 (TIMP-2) is a protein suspected to be crucial in numerous physiological and pathological processes such as morphogenesis, tissue remodelling and metastasis suppression. In animal models, the administration of TIMP-2 to aged mice improved their cognitive functions. Therefore, one can hypothesize that differences in TIMP-2 levels between blood donors and recipients might influence cognitive functions also in humans. However, the stability of TIMP-2 during processing and storage of blood components for transfusion has not been intensively investigated so far. This study determined TIMP-2 concentrations in fresh-frozen plasma (FFP), erythrocyte concentrate (EC) and pathogen-inactivated platelet concentrate (PI-PC) depending on the donor's demographic factors age and gender. MATERIALS AND METHODS: Tissue inhibitor of metalloproteinases 2 was measured in FFP (n = 30), EC (n = 12) and PI-PC (n = 12) using a Q-Plex single-plex immunoassay for chemiluminescence-based detection. Absolute quantification of TIMP-2 was performed with Q-view software. Fresh umbilical cord plasma was used as a positive control. RESULTS: Tissue inhibitor of metalloproteinases 2 was detected in FFP (30/30 samples), EC (11/12 samples) and PI-PC (12/12 samples). The median TIMP-2 concentration in EC (17·2 ng/ml; range: 0-26·5 ng/ml) was significantly lower compared with FFP (63·4 ng/ml; range: 44·4-87·3 ng/ml) or PI-PC (69·9 ng/ml; range: 39·9-83·6 ng/ml). Across all blood components, TIMP-2 levels are comparable in male and female donors and independent of age. CONCLUSION: Tissue inhibitor of metalloproteinases 2 is detectable and stable in FFP, PI-PC and, in low concentration, EC. It can be hypothesized that TIMP-2 will be transmitted to recipients during transfusion.

Clinical adoption of Nephrocheck® in the early detection of acute kidney injury.

Acute kidney injury is a common complication of acute illnesses and is associated with increased morbidity and mortality. Over the past years several acute kidney injury biomarkers for diagnostication, decision-making processes, and prognosis of acute kidney injury and its outcomes have been developed and validated. Among these biomarkers, tissue inhibitor of metalloproteinase-2 (TIMP-2) and insulin-like growth factor-binding protein 7 (IGFBP7), the so-called cell cycle arrest biomarkers, showed a superior profile of accuracy and stability even in patients with substantial comorbidities. Therefore, in 2014, the US Food and Drug Administration approved the use of the product of TIMP-2 and IGFBP7 ([TIMP-2] × [IGFBP7]), known as cell cycle arrest biomarkers, to aid critical care physicians and nephrologists in the early prediction of acute kidney injury in the critical care setting. To date, Nephrocheck® is the only commercially available test for [TIMP-2] × [IGFBP7]. In this narrative review, we describe the growing clinical and investigational momentum of biomarkers, focusing on [TIMP-2] × [IGFBP7], as one of the most promising candidate biomarkers. Additionally, we review the current state of clinical implementation of Nephrocheck®.

The Behavior of MMP-2, MMP-7, MMP-9, and Their Inhibitors TIMP-1 and TIMP-2 in Adenoma-Colorectal Cancer Sequence.

BACKGROUND: We and others have previously shown that matrix metalloproteinases (MMPs) play a role in colorectal cancer (CRC) invasion and metastasis. However, the serum changes of various MMPs and their inhibitors (TIMPs) have scarcely been concomitantly investigated in identical blood samples in the normal colon-adenoma-CRC sequence. METHODS: The MMP-2, MMP-7, MMP-9, TIMP-1, and TIMP-2 serum antigen concentrations were determined concomitantly in 19 tumor-free control patients, 19 patients with high-risk colorectal adenoma, and 47 patients with CRC by ELISA technique. The analyzed parameters were also investigated in correlation with CRC stages. Statistical analysis with one-way ANOVA and Student's t test was performed. p values <0.05 were considered significant. RESULTS: Serum antigen levels of MMPs and TIMPs were significantly increased in patients with CRC and adenomas compared to controls (mean values, ng/mL) (MMP-7: 5.88, 4.44, and 2.89, respectively, p = 0.001; MMP-9: 1,075.81, 999.22, and 845.97, respectively, p = 0.01; TIMP-1: 241.80, 205.98, and 166.53, respectively, p = 0.001; TIMP-2: 83.40, 80.30, and 69.62, respectively, p = 0.01). The elevated serum MMP-7, MMP-9, TIMP-1, and TIMP-2 levels significantly correlated with advanced tumor stages (p < 0.05). No statistically significant differences were observed in MMP-2 levels. CONCLUSIONS: We demonstrate that serum antigen concentrations of MMP-7, MMP-9, TIMP-1, and TIMP-2 were significantly increased in patients with CRC and adenomas compared to controls. These results suggest that MMPs and their inhibitors TIMP-1 and TIMP-2 play an important role in CRC invasion; however, they are also activated in premalignant adenomas. Furthermore, MMP-7, MMP-9, TIMP-1, and TIMP-2 may have a potential prognostic impact in CRC.

Combination of biomarker with clinical risk factors for prediction of severe acute kidney injury in critically ill patients.

BACKGROUND: Acute kidney injury (AKI) occurs commonly in the intensive care unit (ICU). Insulin-like growth factor-binding protein 7 (IGFBP7) and tissue inhibitor of metalloproteinase-2 (TIMP-2), known as [TIMP-2] x [IGFBP7] (NephroCheck), have been identified as novel biomarkers for the prediction of AKI risk. However, the effective use of disease biomarkers is indispensable from an appropriate clinical context. We conducted a retrospective cohort study to find risk factors and assess the performance of the combination of NephroCheck with risk factors, so as to provide feasible information for AKI prediction. METHODS: All patients who were admitted in the ICU (from June 2016 to July 2017) participated in the study. The primary outcome was the detection of severe AKI within the first 7 days after patients being admitted to the ICU. The predictors were separated into three categories: chronic risk factors, acute risk factors and biochemical indicators. RESULTS: The study included 577 patients. 96 patients developed to severe AKI (16.6%) within 7 days. In addition to NephroCheck (+) (OR = 2.139, 95% CI (1.260-3.630), P = 0.005), age > 65 years (OR = 1.961, 95% CI (1.153-3.336), P = 0.013), CKD (OR = 2.573, 95% CI (1.319-5.018), P = 0.006) and PCT (+)(OR = 3.223, 95% CI (1.643-6.321), P = 0.001) were also the independent predictors of severe AKI within 7 days. Compared to NephroCheck (+) only (AUC = 0.66, 95% CI:0.60-0.72), the combination of NephroCheck (+) and risk factors (age > 65 years, CKD and PCT positive) (AUC = 0.75, 95% CI:0.70-0.81) led to a significant increase in the area under ROC curve for severe AKI prediction within 7 days. CONCLUSIONS: Although NephroCheck is an effective screening tool for recognizing high-risk patients, we found that combination with biomarker and risk factors (age > 65 years, CKD, procalcitonin positive) for risk assessment of AKI has the greatest significance to patients with uncertain disease trajectories.

Perioperative Renoprotection: Clinical Implications.

Acute kidney injury (AKI) remains a common complication in the perioperative setting affecting patients' short- and long-term outcome. Because therapeutic options are restricted to the use of renal replacement therapy, preventive strategies have become increasingly important. Several substances have been investigated for preventing AKI with limited to no effects. The lacking effectiveness of all these therapies might be caused by the fact that the therapy was started too late. In all the studies, therapy was initiated once a reduced kidney function occurred. In contrast to the classical functional biomarkers, new renal biomarkers allow to identify kidney damage without a loss of function thus enabling the implementation of preventive measures at the stage of renal stress. The most promising preventive strategy to date seems to implement a bundle of supportive measures in patients at high risk for AKI as recommended by the Kidney Disease: Improving Global Outcomes (KDIGO) group. This strategy includes the avoidance of nephrotoxic drugs and contrast agents, avoidance of hyperglycemia, optimization of perfusion pressure and hemodynamics with consideration of a functional hemodynamic monitoring, and close monitoring of renal function in patients at high risk for AKI. This review discusses new renal biomarkers for identifying kidney damage, the background of why the different measures of the KDIGO bundle might positively affect renal function and prevent the development of AKI, and presents the current literature of biomarker-based approaches in AKI.

Activities and polymorphisms of MMP-2 and MMP-9, smoking, diabetes and risk of prostate cancer.

Matrix metalloproteinases (MMPs) are a group of zinc dependent enzymes that are involved in tumor cell invasion and metastasis. The role of MMP-2 and -9 genetic polymorphism in different malignancies has been the subject of numerous studies. The present research has attempted to discover any positive correlation between MMP-2 and MMP-9 SNPs and prostate cancer (PCa) in patients with a history of either diabetes or smoking habits. 112 PCa-patients and 150 unrelated healthy-controls that matched for age and sex were selected for present case-control study. MMP-2 -1575G/A and MMP-9 -1562 C/T polymorphisms detected by PCR-RFLP, serum tissue inhibitors of metalloproteinases (TIMP-1 and TIMP-2), testosterone, prostate-specific antigen (PSA), free-prostate-specific-antigen (fPSA), and fPSA/PSA levels were detected by ELISA and enzyme assay, respectively. MMP-2 and MMP-9 activities were measured by gelatin-zymography. Covariates were considered as age, status of cigarette smoking, and a possible history of diabetes mellitus (DM). The frequency of -1575 MMP-2 A/A + A/G and -1562 MMP-9 C/T + T/T genotypes were higher in PCa-patients with DM (74.3%,p = 0.003) and with smoking habits (72.5%,p = 0.005). These genotypes were associated with the increased risk of prostate cancer in smokers (3.52-folds) and in individuals with history of DM (4.34-folds). A significant positive association was found between level of TIMPs (TIMP -1 and TIMP-2) and BMI in PCa-patients and also between testosterone levels and MMP-9 activity in healthy control subjects. For the first time, this study demonstrated that activities of MMP-2 -1575G/A and MMP-9 -1562C/T variants in association with smoking and diabetes are considered significant risk factors for PCa.

Atrial matrix remodeling in atrial fibrillation patients with aortic stenosis.

BACKGROUND: This study aimed to evaluate atrium extracellular matrix remodeling in atrial fibrillation (AF) patients with severe aortic stenosis, through histological fibrosis quantification and extracellular matrix gene expression analysis, as well as serum quantification of selected protein targets. METHODS: A posthoc analysis of a prospective study was performed in a cohort of aortic stenosis patients. Between 2014 and 2019, 56 patients with severe aortic stenosis submitted to aortic valve replacement surgery in a tertiary hospital were selected. RESULTS: Fibrosis was significantly increased in the AF group when compared to sinus rhythm (SR) patients (p = 0.024). Moreover, cardiomyocyte area was significantly higher in AF patients versus SR patients (p = 0.008). Conversely, collagen III gene expression was increased in AF patients (p = 0.038). TIMP1 was less expressed in the atria of AF patients. MMP16/TIMP4 ratio was significantly decreased in AF patients (p = 0.006). TIMP1 (p = 0.004) and TIMP2 (p = 0.012) were significantly increased in the serum of AF patients. Aortic valve maximum (p = 0.0159) and mean (p = 0.031) gradients demonstrated a negative association with serum TIMP1. CONCLUSIONS: Atrial fibrillation patients with severe aortic stenosis present increased atrial fibrosis and collagen type III synthesis, with extracellular matrix remodelling demonstrated by a decrease in the MMP16/TIMP4 ratio, along with an increased serum TIMP1 and TIMP2 proteins.

Influence of patients' clinical features at intensive care unit admission on performance of cell cycle arrest biomarkers in predicting acute kidney injury.

Objectives: Identification of acute kidney injury (AKI) can be challenging in patients with a variety of clinical features at intensive care unit (ICU) admission, and the capacity of biomarkers in this subpopulation has been poorly studied. In our study we examined the influence that patients' clinical features at ICU admission have over the predicting ability of the combination of urinary tissue inhibitor of metalloproteinase-2 (TIMP2) and insulin-like growth factor binding protein 7 (IGFBP7). Methods: Urinary [TIMP2]•[IGFBP7] were measured for all patients upon admission to ICU. We calculated the receiver operating characteristics (ROC) curves for AKI prediction in the overall cohort and for subgroups of patients according to etiology of ICU admission, which included: sepsis, trauma, neurological conditions, cardiovascular diseases, respiratory diseases, and non-classifiable causes. Results: In the overall cohort of 719 patients, 239 (33.2%) developed AKI in the first seven days. [TIMP2]•[IGFBP7] at ICU admission were significantly higher in AKI patients than in non-AKI patients. This is true not only for the overall cohort but also in the other subgroups. The area under the ROC curve (AUC) for [TIMP2]•[IGFBP7] in predicting AKI in the first seven days was 0.633 (95% CI 0.588-0.678), for the overall cohort, with sensitivity and specificity of 66.1 and 51.9% respectively. When we considered patients with combined sepsis, trauma, and respiratory disease we found a higher AUC than patients without these conditions (0.711 vs. 0.575; p=0.002). Conclusions: The accuracy of [TIMP2]•[IGFBP7] in predicting the risk of AKI in the first seven days after ICU admission has significant variability when the reason for ICU admission is considered.

Role of MMP-2 and its inhibitor TIMP-2 as biomarkers for susceptibility to systemic lupus erythematosus.

Aim: To investigate the possible association between MMP-2 (-1575 G/A, -1306 C/T) and its inhibitor TIMP-2 (-418 G/C) functional polymorphisms with development of severity in systemic lupus erythematosus (SLE) patients. Materials & methods: 150 SLE patients and matched healthy controls were recruited. Polymorphisms were detected by PCR-RFLP and serum levels by ELISA. Results: Mean MMP-2 and TIMP-2 serum level and mRNA expression were significantly increased in SLE cases as compared with controls (p < 0.0001). The concomitant presence of both MMP-2 1575A and its inhibitor TIMP-2 418C alleles synergistically increased the risk of SLE by 3.25-fold (CI: 1.44-7.34, p = 0.003). Conclusion: MMP-2, TIMP-2 and MMP-2/TIMP-2 ratios may act as biomarkers for susceptibility to SLE.

Association between Matrix Metalloproteinases, Their Tissue Inhibitor and White Matter Lesions in Mild Cognitive Impairment.

BACKGROUND: White matter lesions are frequently found in mild cognitive impairments and Alzheimer's disease. Matrix metalloproteinases and the tissue inhibitor of metalloproteinases are implicated in amyloid-ß catabolism and blood brain barrier permeability. However, it remains unclear whether they are associated with white matter lesions in Alzheimer's disease. OBJECTIVE: The aim of this study was to examine the association of matrix metalloproteinases and tissue inhibitor of metalloproteinases with white matter degeneration in subjects with amyloid-positive mild cognitive impairment. METHODS: Thirty subjects with amnestic mild cognitive impairment (14 men and 16 women; mean age, 75.6 ± 5.8 years) underwent magnetic resonance imaging, 11C-Pittsburgh Compound B positron emission tomography, and 18F-fluorodeoxyglucose positron emission tomography. Levels of plasma matrix metalloproteinases and tissue inhibitor of metalloproteinases were measured using multiplex assays. All subjects had an abnormal brain amyloid burden. Subjects were divided into two groups according to the presence of white matter lesions using the Fazekas scale. Cognitive function testing results i.e., mean 11C-Pittsburgh Compound B and 18F-fluorodeoxyglucose uptake, concentrations of matrix metalloproteinases and tissue inhibitor of metalloproteinases, and matrix metalloproteinases/tissue inhibitor of metalloproteinases ratios were compared between the groups. Correlation analysis was conducted to investigate the association between Fazekas scale score and clinical and neuroimaging variables as well as concentrations of matrix metalloproteinases and tissue inhibitor of metalloproteinases. RESULTS: Matrix metalloproteinases-2, -8, and -9 levels, matrix metalloproteinases-2/ tissue inhibitor of metalloproteinases-2, matrix metalloproteinases-8/ tissue inhibitor of metalloproteinases-1, and matrix metalloproteinases-9/tissue inhibitor of metalloproteinases-1 significantly increased and tissue inhibitor of metalloproteinases-1 and-2 levels significantly decreased in the group with white matter lesions compared with the group without white matter lesions. Matrix metalloproteinases-2, -8, and -9 levels correlated positively and tissue inhibitor of metalloproteinases-1 and -2 levels correlated negatively with Fazekas scale score. CONCLUSION: Plasma matrix metalloproteinases-2, -8, -9 and tissue inhibitor of metalloproteinases-1 and -2 levels are associated with white matter lesions in the mild cognitive impairment stage of Alzheimer's disease.