Applicability of in vitro-in vivo translation of cathepsin K inhibition from animal species to human with the use of free-drug hypothesis.

The correlation of in vitro inhibition of cathepsin K (CatK) activity and in vivo suppression of collagen I biomarkers was examined with three selective CatK inhibitors to explore the potential translatability from animal species to human. These inhibitors exhibited good in vitro potencies toward recombinant CatK enzymes across species, with IC50 values ranging from 0.20 to 6.1 nM. In vivo studies were conducted in animal species following multiple-day dosing of the CatK inhibitors to achieve steady-state plasma drug concentration-time profiles. Measurement of urinary bone resorption biomarkers (cross-linked N-terminal telopeptide and helical peptide of type I collagen) revealed drug concentration-dependent suppression of biomarkers, with EC50 values estimated to be 12 to 160 nM. Marked improvement in the correlation between in vitro and in vivo CatK activities was observed with the application of unbound (free) fraction in plasma, consistent with the conditions stipulated by the free-drug hypothesis. These results indicate that the in vitro-in vivo translation of CatK inhibition observed in animal species can translate to humans when the unbound fraction of the inhibitor is considered. Interestingly, residual levels of urinary bone resorption marker were detected as the suppression reached saturation (at an average of 82% inhibition), an apparent phenomenon observed regardless of the species, biomarker, or compound examined. Since cathepsin enzymes other than CatK were reported to catalyze cleavage of collagen I, it is hypothesized that CatK-mediated degradation of collagen I in bone represents ~82% of overall collagen I turnover in the body.

Urine-based biomarkers for the early detection and surveillance of non-muscle invasive bladder cancer.

Bladder cancer has a very high frequency of recurrence and therefore requires lifelong surveillance, traditionally consisting of serial cystoscopy and cytology. These tests are both invasive and expensive, with considerable inter-user and inter-institutional variability. In addition, the sensitivity of cytology in detecting low-grade tumors is low. Therefore, there has been active investigation into urinary biomarkers that can either supplement or supplant these tests. At this point there are only six urine-based tests that are FDA-approved in bladder cancer surveillance, but a wide variety of other biomarkers are being studied. In this review, we examine the natural history of bladder cancer as well as the rationale and performance of an ideal urinary biomarker. The authors describe the FDA-approved biomarkers such as Bladder Tumor Antigen, ImmunoCyt, Nuclear Matrix Protein-22, and Fluorescent In Situ Hybridization, as well as the most promising investigational tests (i.e., Urinary bladder cancer test, BLCA-1, BLCA-4, hyaluronic acid, hyaluronidase, Lewis X antigen, microsatellite analysis, Quanticyt, soluble Fas, Survivin, and telomerase). The biological foundation, methodologies, and diagnostic performance of the biomarkers are discussed. The characteristics of the biomarkers are compared to urine cytology. At this time, urine biomarkers are utilized in a variety of clinical situations but their role is not well defined. The goal of identifying an optimal marker that will replace cystoscopy and/or cytology is still ongoing.

Focus on urinary bladder cancer markers: a review.

Finding and development of new bladder cancer markers is still a very dynamic field. Because of the mass of all these markers it is impossible to report all of them. This paper reviews the role of bladder cancer markers in diagnosis and highlights the most important biomarkers studied and reported recently. A medline based literature search was performed to examine the field of bladder cancer markers. Major topics focus on selected bladder cancer markers from nearly all categories of the wide field of bladder cancer markers: Hematuria, FISH, FGFR3, SURVIVIN, u-PAR, TP53 mutation, HER-2/neu, TPA, NMP22, CK-19, CK-20, CYFRA 21-1. The use and clinical importance as diagnostic help are discussed. In this review a highlight to some of the most important markers was made. Further determination of recurrence and progression marker will contribute to establish better treatments for the individual patient. Molecular staging of urological tumors will allow selecting cases that will require systemic treatment. It is necessary and important to integrate under the same objectives basic and clinical research.

Urinary cystatin C as a specific marker of tubular dysfunction.

BACKGROUND: Cystatin C (CST3), a strong inhibitor of cysteine proteinases, is freely filtered by the kidney glomerulus and is reabsorbed by the tubules, where it is almost totally catabolized, with the remainder then eliminated in urine. In tubular diseases, it seems sensible to postulate that CST3 degradation would be reduced and consequently an increase in its urinary elimination would be observed. METHODS: We report here the development of an automatic quantitative assay to measure CST3 concentrations in urine using a Behring N-Latex Cystatin C kit on a BNII laser nephelometer. We tested its clinical relevance on several kidney disease patients. RESULTS: This assay is sensitive (limit of detection 0.008 mg/L) and precise (within- and between-day CVs < 4%). Reference values for freshly collected urine samples range from 0.03 to 0.18 mg/L. Mean urine CST3 concentrations obtained from 52 patients with kidney tubular disease (4.31 +/- 3.85 mg/L) were significantly higher than those for 60 controls (0.096 +/- 0.044 mg/L; p < 0.0001) and 47 glomerular disease patients (0.106 +/- 0.133 mg/L; p < 0.0001). CONCLUSION: Increased urinary CST3 concentrations allow the accurate detection of tubular dysfunction among pure and mixed nephropathies. Because of its ability to be processed on automated clinical chemistry analyzers, this assay could easily be used as an adjunct to the standard panel used to screen kidney pathologies, even in emergency situations.

[Cystatin C as a marker of glomerular filtration rate]. / Cystatyna C jako wskaznik przesaczania klebuszkowego nerek.

The assessment of the glomerular filtration rate (GFR) is the most commonly used test of renal function. Cystatin C, a cysteine protease inhibitor, which can be measured by light scattering immunoassay, possesses many of the attributes required of the ideal GFR marker. This paper reviews so far obtained results dealing with cystatin C measurement, reference intervals and its diagnostic significance in nephropathy. Although serum cystatin C can generally be recommended as a marker of GFR, especially to detect mild GFR reductions, further clinical studies should be performed to confirm the validate in renal transplants and cancer patients.

[Concentration of cysteine proteinase inhibitors in urine, amniotic fluid and serum from women in pregnancy complicated by EPH-gestosis]. / Stezenie inhibitorów proteinaz cysteinowych w moczu, plynie owodniowym i surowicy kobiet w ciazy powiklanej EPH-gestoza.

Cysteine proteinase inhibitors (IPC) concentration was measured by the modified Barrett method using papaine in urine, amniotic fluid and serum obtained from the healthy labored women and from labored women in pregnancy complicated by EPH-gestosis. It was noticed the statistically significant increase in the IPC concentration in the material from the pregnant women with EPH-gestosis comparing to the women, which pregnancy had the physiologically normal course.

Identification of novel urinary metabolites of the lipid peroxidation product 4-hydroxy-2-nonenal in rats.

Following iv administration of 4-hydroxy-2-nonenal (HNE) and [4-3H]HNE to rats, 15 polar urinary metabolites accounting for about 50% of the urinary radioactivity were separated by HPLC. Among them, eight major compounds and tritiated water were quantified. The metabolites were unequivocally characterized using GC/MS and ESI/MS/MS/MS. Most of "HNE polar metabolites" originate from omega-oxidation of 4-hydroxy-2-nonenoic acid (HNA): 9-hydroxy-HNA, its mercapturic acid conjugate, and two diastereoisomers of the corresponding lactone. The oxidation of 9-hydroxy-HNA by alcohol and aldehyde dehydrogenases leads to the excretion of 9-carboxy-HNA and of the corresponding lactone mercapturic acid conjugate. 1, 4-Dihydroxy-2-nonene (DHN) originating from the reduction of HNE by alcohol dehydrogenase was to a lesser extent omega-hydroxylated, leading to 9-hydroxy-DHN which was excreted as a mercapturic acid conjugate (two diastereoisomers).

Clearance of Clara cell secretory protein 16 (CC16) and surfactant proteins A and B from blood in acute respiratory failure.

Surfactant proteins A and B (SP-A and SP-B) enter the circulation in a manner that acutely reflects changes in pulmonary function in patients with acute respiratory failure (ARF). There is a small but significant gradient in SP-A and SP-B from arterial to mixed venous (A-V) blood, and since we have detected both proteins in urine, the kidney may be a major site of their systemic clearance. Clara cell secretory protein 16 (CC16), which leaks from the respiratory tract, is known to be freely eliminated by the kidney. Lung plasma protein levels will depend on the rates of both protein entry into and clearance from plasma. In order to study the limiting variable determining these levels, we compared plasma CC16, SP-A, and SP-B in matching A-V blood samples from 37 ARF patients with indices of lung dysfunction and glomerular filtration rate (GFR) (of plasma cystatin C and creatinine). Cystatin C, CC16, SP-A, and SP-B were reduced in mixed venous plasma (all p < 0.001) and their A-V gradients were directly related to their arterial levels (all p < 0.03). Whereas CC16, SP-A, and SP-B reflected blood oxygenation (all p < 0.05), only SP-A and SP-B were related to lung injury score (LIS) (both p < 0.05). In contrast, whereas the clearances of both CC16 and cystatin C were related to that of creatinine (p < 0.02 for both), the clearances of SP-A and SP-B were not. Our study confirms that all three lung proteins are acutely cleared from the circulation of patients with ARF (half-lives < 18 min), and we conclude that whereas the plasma concentration of CC16 depends on GFR, plasma concentrations of SP-A and SP-B reflect lung function independently of this variable.

1,4-Dihydroxynonene mercapturic acid, the major end metabolite of exogenous 4-hydroxy-2-nonenal, is a physiological component of rat and human urine.

In the present study 1,4-dihydroxynonene mercapturic acid (DHN-MA), previously shown to be the major urinary metabolite of 4-hydroxy-2-nonenal (HNE) administered to the rat, was characterized and determined to be a normal constituent of rat and human urine. DHN-MA was excreted as a mixture of at least two stereoisomers as determined by ion trap LC-MS/MS/MS after solid-phase extraction and HPLC purification. The 24-h urinary excretion of this compound was about 10 ng and 5 microg for rat and human, respectively. This end metabolite of the lipid peroxidation product HNE could represent a specific and noninvasive biomarker.

Cysteine peptidase inhibitors and activator(s) in urine of patients with colorectal cancer.

The total activity of cysteine peptidase inhibitors and activator(s) was determined in the samples of urine received from colorectal cancer patients. Patients with peptic ulcer and healthy volunteers agreed to be a control group. The studies revealed a marked difference between the values of the determined parameters for the patients with colorectal cancer and those for the control group. Determination of cysteine peptidase inhibitors in patient's urine is proposed as a new diagnostic procedure.

Decrease in vivo of cysteine endopeptidases in blood of patients with tumor of the larynx.

Since cysteine endopeptidase (cathepsins B and L) have been proposed to be implicated in tumor malignancy, we have attempted to decrease these in vivo. Large amounts of urine cysteine peptidase inhibitors (UCPI) are present in the urine of patients. Our results indicate protective effects of a UCIP preparation against human serum cysteine endopeptidases.

Plasma protein homeostasis in chronic hemodialysis patients.

The concentrations of 25 plasma proteins were measured in 29 patients with chronic renal insufficiency. All the patients had terminal renal failure and were treated with intermittent hemodialysis, but were otherwise in good general condition at the time of investigation. The plasma levels of 8 proteins with M(r) < 50 kD were significantly elevated compared to normal subjects. In contrast, only 2/17 proteins of greater size were found in increased concentrations. The degree of increase in concentration differed substantially between individual low molecular weight proteins, suggesting a complex metabolism in addition to delayed renal elimination. Acute phase proteins and immunoglobulins were not affected by renal insufficiency per se, although erythrocyte sedimentation rates were generally high. The synthesis of acute phase proteins increased normally during the course of inflammation. We conclude that although the sedimentation rate is of no value, complicating inflammatory processes can be traced by quantitative analysis of acute phase proteins, including C-reactive protein, even in patients with severe chronic renal insufficiency.

Method of purification of thiol proteinase inhibitors from human urine.

Urinary thiol proteinase inhibitors (UTPI) had been isolated from their complex with papain. Almost 90% of these inhibitors, previously inactivated by native or immobilized papain, were recovered after heating the complex to 80 degrees C at pH 2.0 for 20 min. Two protein inhibitors with molecular weights of 76,000 (UTPI-76) and about 45,000 (UTPI-45) were isolated from urine of patients with malignant colorectal tumor. UTPI-fraction consisted of about 40% of UTPI-76 (probably light form of kininogen) and of 60% of UTPI-45 fraction. The inhibitors differed in affinity to Concanavalin A. No electrophoretic mobility changes of both UTPI, before and after isolation by described affinity chromatography were observed.