Assessment of cell cycle arrest biomarkers and neutrophil gelatinase-associated lipocalin to distinguish acute kidney injury from other diseases in dogs.

BACKGROUND: Cell cycle arrest biomarkers (tissue inhibitor of metalloproteinase-2 [uTIMP-2] and insulin-like growth factor binding protein 7 [uIGFBP7]), and neutrophil gelatinase-associated lipocalin (NGAL) variables are valuable biomarkers for early diagnosis of acute kidney injury (AKI) in people. OBJECTIVES: To evaluate uTIMP-2, uIGFBP7, fractional excretion of NGAL (FeNGAL), and urinary to serum NGAL ratio (u/sNGAL) in healthy dogs, dogs with AKI, dogs with chronic kidney disease (CKD), and critically ill (CI) dogs. ANIMALS: Forty-two client-owned dogs (healthy, n = 10; AKI, n = 11; CKD, n = 11; CI, n = 10). METHODS: Prospective, observational study. After assessment of routine renal biomarkers, stress (uTIMP-2, uIGFBP7) and damage (NGAL) biomarkers were measured, using ELISA kits, and normalized to urinary creatinine (uCr). RESULTS: Normalized uTIMP-2 and [uTIMP-2] × [uIGFBP7]/uCr were significantly higher in the AKI group (median 151.9 [range, 2.2-534.2] and 62.9 [1.1-266.8] pg/mL respectively), compared to healthy dogs (0.3 [0.2-74.7]; P < .001 and 0.16 [0.1-58.1] pg/mL; P < .001), dogs with CKD (0.7 [0.3-742.5]; P = .04 and 0.37 [0.2-180.1] pg/mL; P = .03) and CI dogs (1.9 [0.2-37.0]; P = .03 and 0.8 [0.1-16.1] pg/mL; P = .02). Fractional excretion of NGAL was significantly higher in dogs with AKI (54.17 [7.93-155.32] %), than in healthy (0.03 [0.01-0.21] %; P < .001) and CI dogs (3.05 [0.05-28.86] %; P = .02). CONCLUSIONS AND CLINICAL IMPORTANCE: Normalized uTIMP-2, [uTIMP-2] × [uIGFBP7]/uCr, and FeNGAL can be valuable renal biomarkers for early diagnosis of AKI in dogs.

The Possible Effect of ß-Blocker Use on the Circulating MMP-2/TIMP-2 System in Patients with Chronic Kidney Disease on Conservative Treatment.

Background: The purpose of the study was to determine whether the use of ß-adrenoceptor antagonists (ß-blockers) can affect metalloproteinase 2 (MMP-2) and its tissue inhibitor (TIMP-2) in patients with chronic kidney disease (CKD) on conservative treatment. Methods: The circulating MMP-2/TIMP-2 system, proinflammatory cytokines (tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6), and the marker of oxidative stress-Cu/Zn superoxide dismutase (Cu/Zn SOD)-were measured in 23 CKD patients treated with ß-blockers [ß-blockers (+)] and in 27 CKD patients not receiving the above medication [ß-blockers (-)]. Results: The levels of MMP-2, TIMP-2, and IL-6 were significantly lower in the ß-blockers (+) than in the ß-blockers (-) group, whereas Cu/Zn SOD concentrations were not affected by ß-blocker use. There was a strong, independent association between MMP-2 and TIMP-2 in both analyzed patient groups. In the ß-blockers (+) group, MMP-2 levels were indirectly related to the signs of inflammation, whereas in the ß-blockers (-) group, the alterations in the MMP-2/TIMP-2 system were associated with the oxidative stress marker and CKD etiology. Conclusions: This study is the first to suggest that the use of ß-blockers was associated with the reduction in IL-6 and the MMP-2/TIMP-2 system in CKD, providing a pharmacological rationale for the use of ß-blockers to reduce inflammation and abnormal vascular remodeling in CKD.

TIMP2 mediates endoplasmic reticulum stress contributing to sepsis-induced acute kidney injury.

Tissue inhibitor of metalloproteinase 2 (TIMP2) has been recognized as an important biomarker for predicting acute kidney injury (AKI) because of its involvement in the process of inflammation and apoptosis in septic AKI. Endoplasmic reticulum (ER) stress, a condition of disrupted ER homeostasis, is implicated in multiple pathophysiological processes, including kidney disease. Herein, we investigated the correlation between ER stress and septic AKI and further explored how TIMP2 regulated ER stress-mediated apoptosis. To assess the role of TIMP2 in sepsis-induced AKI, we used a cecal ligation and puncture (CLP) model in mice with tubule-specific deficiency of TIMP2 (Ksp-Cre/TIMP2flox/flox ) and their wild-type counterparts. Compared to the wild-type mice, TIMP2-deficient mice demonstrated lower serum creatinine levels and decreased ER stress-mediated apoptosis when subjected to CLP. Interestingly, in human kidney (HK-2) cells, overexpression of TIMP2 caused ER stress, whereas TIMP2 knockdown attenuated lipopolysaccharide-induced ER stress and apoptosis. TIMP2 interacted with the binding immunoglobulin protein, an ER chaperone, and facilitates its extracellular secretion, thereby triggering ER stress. This study identified that the deletion of TIMP2 in mouse tubules mitigated sepsis-induced AKI by inhibiting ER stress-mediated apoptosis, which might be a potential therapeutic strategy to alleviate renal injury.

The predictive value of TIMP-2 and IGFBP7 in delayed renal function recovery after DCD renal transplantation / 中华泌尿外科杂志

Objective:This study is to investigate the predictive value of serum levels of TIMP-2 and insulin-like growth factor-binding protein 7(IGFBP7) in patients with DCD(donation after cardiac death) kidney transplantation.Methods:A prospective research design was used to select DCD kidney transplant patients admitted to the Li Huili Hospital of Ningbo University from January 2018 to October 2020.Inclusion criteria: ①Complete data; ②There were no serious complications affecting the function of the transplanted kidney in the early postoperative period.Exclusion criteria: ①Incomplete data; ②Patients were unable or unwilling to cooperate with the study; ③Severe complications affecting the function of the transplanted kidney occurred early after the operation.The ELASE method was used to quantitatively detect the serum TIMP-2 and IGFBP7 levels at 6, 12, 24, 48, 72 hours and 7 days after renal transplantation, and monitor the serum creatinine values during the same period and 21 days after the operation. According to the occurrence of DGF, the measured values of TIMP-2 and IGFBP7 at different time points and their product's ability to predict the occurrence of DGF after kidney transplantation were analyzed. The receiver operating characteristic (ROC) curve and area under the curve (AUC) were used to evaluate the diagnostic efficacy of TIMP-2 and IGFBP7 for DGF.Results:A total of 33 patients were enrolled, 7 patients (21.2%) in the DGF group and 26 patients (78.8%) in the non-DGF group. Between the two groups, the donor glomerular filtration rate were [98.5(15.8-132.5)ml/(min·1.73m 2) and 79.1(60.6-102.5)ml/(min·1.73m 2)], recipient gender (male/female: 3/4 cases and 10/16 cases), recipient age [48(34-56) Years old and 45(23-61) years old], the recipient's preoperative creatinine [1114.0(731.4-1293.0)μmol/L and 858.4(657.6-1051.9)μmol/L], the recipient's preoperative urea nitrogen [15.0(13.2-19.6)mmol/L and 17.3(13.6-20.9)mmol/L], receptor preoperative albumin [43.5(38.5-45.3)mmol/L and 41.2(37.5-46.1) mmol/L], recipient dialysis method [hemodialysis/peritoneal dialysis: 3/4 cases and 9/17 cases], warm ischemia time [6(5-7) and 5(4-6) min, there was no statistically significant difference] ( P>0.05). The values of serum IGFBP7 and TIMP-2×IGFBP7 in the DGF group were higher than those in the non-DGF group at all time points ( F=15.753, P=0.040; F=13.000, P=0.024), while serum TIMP-2 was not significant between the two groups difference ( F=1.157, P=0.075). For the diagnostic value of DGF, the AUC of serum IGFBP7 at 48 h after surgery was 0.863 (95% CI 0.696-1.000, P=0.004). When 5.97 ng/ml was used as the cut-off value, the sensitivity was 85.7% and the specificity was 80.8 %. The AUC of TIMP-2×IGFBP7 at 48 hours after surgery was 0.819 (95% CI 0.641-0.996, P=0.011). When 62.06(ng/ml) 2 was used as the cutoff value, the sensitivity was 71.4% and the specificity was 80.8%.There was no statistical difference in the area under the curve between the two ( P>0.05). There were differences in the dynamic trend of serum IGFBP7 and creatinine in the DGF group. Serum IGFBP7 at 7 days after surgery was positively correlated with creatinine at 21 days after surgery. Conclusion:Serum IGFBP7 and TIMP-2×IGFBP7 could predict the occurrence of DGF after DCD donor kidney surgery. The predictive value changes with time. Among them, 48h and 7d after surgery are the most valuable. However, serum TIMP-2 has not been found to have predictive value in this study.

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.

The effects of aging, diabetes mellitus, and antiplatelet drugs on growth factors and anti-aging proteins in platelet-rich plasma.

As the aged population continues to markedly increase worldwide, the incidences of diabetes mellitus (DM) and cardiovascular disease (CVD) are increasing. In this study, we investigated the effects of aging, DM, and antiplatelet drugs on growth factors and anti-aging proteins in platelet-rich plasma (PRP). The study participants were classified into the following four groups: Group A, healthy individuals aged ≤45 years; Group B, healthy individuals aged >45 years; Group C, DM patients aged >45 years; and Group D, CVD patients aged >45 years taking antiplatelet drugs. The concentrations of epidermal growth factor (EGF), fibroblast growth factor (FGF)-2, platelet-derived growth factor (PDGF)-AA, PDGF-AB/BB, vascular endothelial growth factor (VEGF)-A, tissue inhibitor of metalloproteinase 2 (TIMP2), insulin-like growth factor 1 (IGF-1), growth differentiation factor (GDF)11, and clusterin in PRP samples were determined to analyze the effects of aging, DM, and antiplatelet drugs. Overall, the concentrations of IGF-1, TIMP2, and clusterin did not vary significantly between the four groups. The concentrations of PDGF-AB/BB (P = 0.010), VEGF-A (P = 0.000), and GDF11 (P = 0.026) were significantly different between Group A and Group B. Further, the concentrations of EGF (P = 0.000) and GDF11 (P = 0.000) were significantly different between Groups B and C. The concentrations of EGF (P = 0.001), VEGF-A (P = 0.000), and GDF11 (P = 0.002) significantly differed between Groups A and C. The concentrations of FGF-2 (P = 0.048), PDGF-AA (P = 0.03), and GDF11 (P = 0.001) were significantly different between Groups B and D. The concentrations of PDGF-AB/BB (P = 0.032), VEGF-A (P = 0.010), and GDF11 (P = 0.02) significantly differed between Groups A and D. We found that PRP contains high concentrations of the growth factors, TIMP2 and GDF11. Aging, DM, and antiplatelet drugs can decrease the concentration of some growth factors and GDF11, which weakens the regenerative capacity and anti-aging effects of PRP and reduces the quality of PRP.

Biomarkers of acute kidney injury: the pathway from discovery to clinical adoption.

Acute kidney injury (AKI) is a common complication of critical illnesses and has a significant impact on outcomes, including mortality and morbidities. Unfortunately, apart from prophylactic measures, no effective treatment for this syndrome is known. Therefore, early recognition of AKI not only can provide better opportunities for preventive interventions, but also opens many gates for research and development of effective therapeutic options. Over the last few years, several new AKI biomarkers have been discovered and validated to improve early detection, differential diagnosis, and differentiation of patients into risk groups for progressive renal failure, need for renal replacement therapy (RRT), or death. These novel AKI biomarkers complement serum creatinine (SCr) and urine output, which are the standard diagnostic tools for AKI detection. In this article, we review the available literature on characteristics of promising AKI biomarkers that are currently the focus of preclinical and clinical investigations. These biomarkers include neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule 1 (KIM-1), liver-type fatty acid-binding protein, interleukin 18 (lL-18), insulin-like growth factor-binding protein 7, tissue inhibitor of metalloproteinase 2 (TIMP-2), calprotectin, urine angiotensinogen (AGT), and urine microRNA. We then describe the clinical performance of these biomarkers for diagnosis and prognostication. We also appraise each AKI biomarker's advantages and limitations as a tool for early AKI recognition and prediction of clinical outcomes after AKI. Finally, we review the current and future states of implementation of biomarkers in the clinical practice.

Serum metalloproteinase-2 and tissue inhibitor of metalloproteinase-2 in lung carcinoma patients.

BACKGROUND: Assessment of serum extracellular matrix (ECM) metalloproteinase MMP-2 and tissue inhibitor of matrix metalloproteinase TIMP-2 concentrations in non-small cell lung carcinoma (NSCLC) patients considering TNM staging. Assessment of the prognostic value of MMP-2 and TIMP-2 concentrations in NSCLC patients. METHODS: The study group consisted of 81 NSCLC patients (24 females and 57 males) aged 46 to 86 years (mean age of 67±8.2 years). The control group comprised 39 randomly selected patients (20 females and 19 males) aged 27 to 73 years (mean age of 47±15.0 years) in whom primary lung cancer was excluded and who were operated on for a calculus of the gallbladder without cholecystitis. Blood serum MMP-2 and TIMP-2 concentrations were determined using an enzyme-linked immunosorbent assay (ELISA)-based test. RESULTS: Statistically significantly higher mean MMP-2 and TIMP-2 concentrations were found in NSCLC patients compared to those in the control group (P<0.001). Statistically significant differences in MMP-2 and TIMP-2 concentrations between patients with T1 and T2 tumour and patients with T3 and T4 tumour, as well as between the group without metastases (N0) and the group with metastases to lymph nodes were demonstrated. Moreover, a significant fall in mean MMP-2 and TIMP-2 concentrations was observed in the postoperative compared to preoperative period (P<0.001). CONCLUSIONS: Serum MMP-2 and TIMP-2 concentrations in NSCLC patients correlated with the tumour size and presence of metastases to lymph nodes and thus may serve as an auxiliary parameter indicating probability of a more advanced stage of lung cancer.

Biomarkers in acute kidney injury - pathophysiological basis and clinical performance.

Various biomarkers of acute kidney injury (AKI) have been discovered and characterized in the recent past. These molecules can be detected in urine or blood and signify structural damage to the kidney. Clinically, they are proposed as adjunct diagnostics to serum creatinine and urinary output to improve the early detection, differential diagnosis and prognostic assessment of AKI. The most obvious requirements for a biomarker include its reflection of the underlying pathophysiology of the disease. Hence, a biomarker of AKI should derive from the injured kidney and reflect a molecular process intimately connected with tissue injury. Here, we provide an overview of the basic pathophysiology, the cellular sources and the clinical performance of the most important currently proposed biomarkers of AKI: neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), liver-type fatty acid-binding protein (L-FABP), interleukin-18 (IL-18), insulin-like growth factor-binding protein 7 (IGFBP7), tissue inhibitor of metalloproteinase 2 (TIMP-2) and calprotectin (S100A8/9). We also acknowledge each biomarker's advantages and disadvantages as well as important knowledge gaps and perspectives for future studies.

Analytical characteristics of a biomarker-based risk assessment test for acute kidney injury (AKI).

BACKGROUND: Acute kidney injury (AKI) is associated with increased mortality, morbidity, hospital length of stay, and costs. A quantitative urine test is available to assess the risk of developing AKI by measuring the concentrations of two protein biomarkers, TIMP-2 and IGFBP-7. The NephroCheck Test combines these concentrations into an AKIRisk Score. The purpose of this study is to characterize the analytical performance characteristics of the AKIRisk Score. METHODS: Linearity and analytical sensitivity were evaluated by following Clinical Laboratory Standards Institute (CLSI) EP06-A and EP17-A, respectively. Precision was evaluated by testing clinical samples and examining the repeatability of test results. Potential interference was evaluated for endogenous and exogenous substances. Sample stability was examined at room temperature and at 2-8°C, as well as the effect of sample centrifugation temperature on test results. RESULTS: The AKIRisk Score exhibits approximately 10% coefficient of variation (CV) at the recommended cutoff value of 0.3 and the limit of quantitation (LoQ) was 0.002. Only albumin, bilirubin (conjugated), and methylene blue interfered with test results, at concentrations exceeding 1250 mg/L, 72 mg/L, and 0.49 mg/L, respectively. AKIRisk Score results were stable for 6h at room temperature, 24h refrigerated, and not impacted by sample centrifugation temperature. CONCLUSIONS: Our studies demonstrate that the AKIRisk Score has robust analytical performance, good precision, minimal analytical interference, acceptable sensitivity, and excellent sample stability.

Effects of Dietary Copper-Methionine on Matrix Metalloproteinase-2 in the Lungs of Cold-Stressed Broilers as an Animal Model for Pulmonary Hypertension.

The objective of the present study was to investigate the effects of different levels of copper (as supplemental copper-methionine) on ascites incidence and matrix metalloproteinase-2 (MMP-2) changes in the lungs of cold-stressed broilers. For this purpose, 480 1-day-old Ross 308 broiler chickens were randomly assigned to six treatments. Treatments consisted of two ambient temperatures (thermoneutral and cold stress) each combined with 0, 100, and 200 mg supplemental copper/kg as copper-methionine in a 2 × 3 factorial arrangement in a completely randomized design with four replicates. Ascites was diagnosed based on abdominal and pericardial fluid accumulation at 45 days of age. Fourty-eight broilers were killed at 38 and 45 days of age, and their lungs were collected for biological analysis. Results showed that MMP-2 increased in the lungs of ascitic broilers and that copper-methionine supplementation significantly reduced MMP-2 in cold-stressed broiler chickens. Treatments did not affect tissue inhibitor of metalloproteinase-2 (TIMP-2) at 38 and 45 days of age, and no difference was observed between 100 and 200 mg/kg copper-methionine treatments. In conclusion, copper-methionine at higher than conventional levels of supplementation decreased ascites incidence in low temperature through reduced MMP-2 concentration. Further research is warranted to investigate the effect of copper on MMP-2 concentrations in other tissues with high oxygen demand.

A chromatin modifier regulates Sertoli cell response to mono-(2-ethylhexyl) phthalate (MEHP) via tissue inhibitor of metalloproteinase 2 (TIMP2) signaling.

Epigenetic silencing mechanisms are essential for regulating germ cell apoptosis in response to different stimuli during complicated spermatogenesis. Herein, we report the potential signaling events related to up-regulation of metastasis associated protein 1 (Mta1), a master chromatin modifier, during mono-(2-ethylhexyl) phthalate (MEHP)-induced Sertoli cells (SCs) injury. Mta1 up-regulation correlated to the gradual increases of MYC expression in MEHP-treated SCs. Selective knockdown of MYC abolished MEHP-induced activation of Mta1, suggesting that MYC may regulate the Mta1 signaling following MEHP injury. Furthermore, MTA1 acted as a specific corepressor of tissue inhibitor of metalloproteinase 2 (Timp2) during SCs injury. Mta1 repressed Timp2 expression either directly by recruiting histone deacetylase 2 onto the Timp2 promoter or indirectly by enhancing NF-κB-mediated inflammatory responses during MEHP injury. This transcriptional and post-translational down-regulation of Timp2/TIMP2 expression consequently resulted in the stimulated activation of matrix metalloproteinase 2 (MMP2) in SCs, which should ultimately promote germ cell death upon MEHP insult. From a functional standpoint, inhibition of endogenous Mta1 expression along with anti-inflammation treatment in cultured SCs could rescue MEHP-inhibited TIMP2 and subsequently rebalanced MMP2 activity to the control level. Together with the recently reported essential role of TIMP2/MMP2 signaling in MEHP-induced specific disruption of junctional complexes in the seminiferous epithelium, our results further substantiate a critical role of Mta1 in the control of SCs response to MEHP stimulation. The MYC/Mta1/TIMP2 circuit may serve as an important scavenger mechanism to help to maintain the capacity of damaged SCs to support germ cell development following MEHP injury.

Molecular mechanisms of tissue inhibitor of metalloproteinase 2 in the tumor microenvironment.

There has been a recent paradigm shift in the way we target cancer, drawing a greater focus on the role of the tumor microenvironment (TME) in cancer development, progression and metastasis. Within the TME, there is a crosstalk in signaling and communication between the malignant cells and the surrounding extracellular matrix. Matrix metalloproteinases (MMPs) are zinc-dependent endoproteases that have the ability to degrade the matrix surrounding a tumor and mediate tumor growth, angiogenesis and metastatic disease. Their endogenous inhibitors, the Tissue Inhibitors of Metalloproteinases (TIMPs), primarily function to prevent degradation of the ECM via inhibition of MMPs. However, recent studies demonstrate that TIMP family members also possess MMP-independent functions. One TIMP member in particular, TIMP-2, has many distinct properties and functions, that occur independent of MMP inhibition, including the inhibition of tumor growth and reduction of angiogenesis through decreased endothelial cell proliferation and migration. The MMP-independent molecular mechanisms and signaling pathways elicited by TIMP-2 in the TME are described in this review.

THE LOCALIZATION AND EXPRESSION OF TIMP-2 IN EXPERIMENTAL HEPATIC FIBROSIS IN RAT / 解放军医学杂志

An experimental immunity hepatic fibrosis rat model was prepared by means of immunologic assault with human serum albumin, and normal rats served as a control group. The immunohistochemistry methods and in situ hybridization were respectively used to detect TIMP 2 mRNA and related antigens in the liver,and to investigate the localization and expression of TIMP 2 in the liver of both normal and experimental hepatic fibrosis rats. The results showed that TIMP 2 mRNA and related antigens in the livers of experimental group were expressed in myofibroblasts and fibroblasts, especially in the portal area and fibrous septum. The positive signal was located in the cytoplasm, but not in the nucleus. On the other hand, there was a high level of expression of TIMP 2 in the liver of the experimental group.It is suggested that in the process of hepatic fibrosis, fibroblasts and myofibroblasts are the major cells expressing TIMP 2. The severer the hepatic fibrosis in the injured liver is, the higher the levels of TIMP 2 related antigens and gene expression are.