The carboxy-terminal cross-linked telopeptide of type I collagen (ICTP) is a potential serum marker of ongoing liver fibrosis

Telopeptide-dependent xenogeneic collagen co-assembly

The function of telopeptide in xenogeneic collagen co-assembly was shown.

Collagen biomarkers and subclinical interstitial lung disease: The Multi-Ethnic Study of Atherosclerosis

BACKGROUND

Lung fibrosis is attributed to derangements in extracellular matrix remodeling, a process driven by collagen turnover. We examined the association of two collagen biomarkers, carboxy-terminal telopeptide of collagen type I (ICTP) and amino-terminal propeptide of type III procollagen (PIIINP), with subclinical interstitial lung disease (ILD) in adults.

METHODS

We performed a cross-sectional analysis of 3244 participants age 45-84 years in the Multi-Ethnic Study of Atherosclerosis. Serum ICTP and PIIINP levels were measured at baseline by radioimmunoassay. Subclinical ILD was defined as high attenuation areas (HAA) in the lung fields on baseline cardiac CT scans. Interstitial lung abnormalities (ILA) were measured in 1082 full-lung CT scans at 9.5 years median follow-up. We used generalized linear models to examine the associations of collagen biomarkers with HAA and ILA.

RESULTS

Median (IQR) for ICTP was 3.2 μg/L (2.6-3.9 μg/L) and for PIIINP was 5.3 μg/L (4.5-6.2 μg/L). In fully adjusted models, each SD increment in ICTP was associated with a 1.3% increment in HAA (95% CI 0.2-2.4%, p = 0.02) and each SD increment in PIIINP was associated with a 0.96% increment in HAA (95% CI 0.06-1.9%, p = 0.04). There was no association between ICTP or PIIINP and ILA. There was no evidence of effect modification by gender, race, smoking status or eGFR.

CONCLUSIONS

Higher levels of collagen biomarkers are associated with greater HAA independent of gender, race and smoking status. This suggests that extracellular matrix remodeling may accompany subclinical ILD prior to the onset of clinically evident disease.

Serum sclerostin in alcoholics: a pilot study

AIMS

Sclerostin is an endogenous inhibitor of the Wnt/β-catenin pathway secreted by osteocytes, which inhibits osteoblast function, differentiation and survival. As a consequence, sclerostin tends to decrease bone mass. Alcoholics frequently present osteoporosis, mainly due to decreased bone synthesis. The behaviour of sclerostin in these patients is unknown. The aim of this work was to analyse the relationship between serum sclerostin levels and bone mineral density (BMD), ethanol consumption, nutritional status, liver function derangement and biomarkers of bone homeostasis in alcoholic patients.

METHODS

We included 31 alcoholic patients, of whom 11 were infected with Hepatitis C virus (HCV) and 7 age and sex-matched controls. All underwent densitometry, and serum sclerostin, osteocalcin, collagen telopeptide, parathyroid hormone (PTH), vitamin D, cortisol and testosterone were determined.

RESULTS

Sclerostin levels were significantly higher in patients (30.95 ± 18.91 pmol/l) than controls (t = 4.4; P < 0.001), especially in non-HCV patients; they showed an inverse correlation with osteocalcin, prothrombin activity and serum albumin, and a direct correlation with bilirubin and telopeptide, but not with BMD, nutritional status or ethanol intake.

CONCLUSIONS

Serum sclerostin was raised in alcoholic patients, and it correlated with decreased markers of bone synthesis and increased markers of bone breakdown. The elevation in sclerostin levels was clearly related with liver function, but not with ethanol intake, nutritional status or concomitant HCV infection.

Bone alterations in hepatitis C virus infected patients

BACKGROUND AND AIMS

Most studies have shown that patients with chronic hepatitis C virus (HCV) infection are affected by osteoporosis. However, liver function impairment and deranged nutrition may both play a role in the bone alterations observed. In some works no osteoporosis was found, and some cases of osteosclerosis have been reported. The aim of the study is to assess bone alterations in treatment-naïve, well-nourished HCV patients, in order to discern whether or not HCV infection causes osteoporosis.

METHODS

Whole-body bone densitometry and assessment of T-score at lumbar spine and hip were performed to 40 patients and 40 age- and sex-matched controls, with a Lunar Prodigy Advance (General Electric, Piscataway, NJ, USA). All the patients underwent liver biopsy. Nutritional evaluation was performed by subjective nutritional assessment, body mass index (BMI), and densitometric assessment of total lean mass and total fat mass. Serum osteocalcin, osteoprotegerin, RANKL, PTH, crosslaps, vitamin D3, testosterone, IGF-1, and estradiol were determined.

RESULTS

Patients did not show differences in total bone mineral density (BMD) or T-score with controls. On the contrary, about a third of them showed positive T scores. Patients showed lower IGF-1, vitamin D3 and testosterone, but higher telopeptide levels, and a trend to higher osteoprotegerin levels. Multivariate analyses disclosed that age, sex, and total lean mass were the only parameters independently related with BMD.

CONCLUSIONS

Therefore, chronic HCV infection in well nourished patients with preserved liver function does not cause osteoporosis.

Prognosis of osteopenia in chronic alcoholics

Osteoporosis is frequent among alcoholics all by a direct effect of ethanol, malnutrition, and liver failure. Therefore, it may be related to survival. The aim of this study was to assess bone mineral density (BMD), bone mineral content, hormonal status, and to determine prognostic value of these parameters in a total of 124 alcoholics followed up for a median period of 57 months. Several bone homeostasis-related hormones were measured in patients and age- and sex-matched controls. Whole-body densitometry was performed by a Hologic QDR-2000 (Waltham, MA) densitometer; nutritional status and liver function were assessed. Sixty patients underwent a second evaluation 6 months later. Patients showed lower serum insulin-like growth factor-1 (median=58, interquartile range [IQR]=33-135 vs. 135ng/mL, IQR=116-243ng/mL, P<.001), vitamin D (25.5, IQR=18.3-36.8 vs. 79.9pg/mL, IQR=59.2-107.8pg/mL, P<.001), and osteocalcin (2.1, IQR=1.1-4.5 vs. 6.5ng/mL, IQR=4.7-8.7ng/mL, P<.001) than controls, and lower BMD values, and lower Z- and T-scores at right and left legs and arms, thoracic and lumbar spine, pelvis, and right and left ribs. By multiple regression analysis, BMD mainly depends on nutritional parameters and liver function. Kaplan-Meier curves show that subtotal BMD and BMD at both arms and pelvis were significantly related with survival. Patients who had lost total hip BMD after 6 months showed a shorter survival than those who had not, but using Cox's regression, encephalopathy, ascites, and nutritional parameters displaced BMD as prognostic factor. Therefore, osteopenia ensues in chronic alcoholic patients. It mainly depends on poor nutrition and is related to survival, although surpassed in this sense by encephalopathy, ascites, and nutritional parameters.

Measurement of matrix metalloproteinase 9-mediated collagen type III degradation fragment as a marker of skin fibrosis

Background

The current study utilized a Bleomycin-induced model of skin fibrosis to investigate the neo-epitope CO3-610 (KNGETGPQGP), a fragment of collagen III released during matrix metalloproteinase-9 (MMP9) degradation of the protein, we have previously described as a novel biomarker for liver fibrosis. The aim was to investigate CO3-610 levels in another well characterised model of fibrosis, to better describe the biomarker in relation to additional fibrotic pathologies.

Methods

Skin fibrosis was induced by daily injections of Bleomycin to a total of 52 female C3 H mice, while control mice (n = 28) were treated with phosphate buffered saline (PBS), for 2, 4, 6 or 8 weeks. Skin fibrosis was evaluated using Visiopharm software on Sirius-red stained skin sections. Urine ELISA assays and creatinine corrections were performed to measure CO3-610 levels.

Results

CO3-610 levels were significantly higher in Bleomycin-treated vs. PBS-treated mice at each time point of termination. The mean increases were: 59.2%, P < 0.0008, at 2 weeks; 113.5%, P < 0.001, at 4 weeks; 136.8%, P < 0.0001 at 6 weeks; 157.2%, P < 0.0001 at 8 weeks). PBS-treated mice showed a non-significant increase in CO3-610 levels (mean increase for weeks 2-8 = 1.7%, P = 0.789) CO3-610 levels assayed in urine were statistically significantly correlated with Western blot analysis showing increased skin fibrosis (P < 0.0001, r = 0.65).

Conclusion

Increased levels in mouse urine of the MMP-9 mediated collagen III degradation fragment CO3-610 were correlated with skin fibrosis progression, suggesting that CO3-610 may be a potential positive biomarker to study the pathogenesis of skin fibrosis in mice.

Measurement of CO3-610, a potential liver biomarker derived from matrix metalloproteinase-9 degradation of collagen type iii, in a rat model of reversible carbon-tetrachloride-induced fibrosis

BACKGROUND AND AIM

The current study utilized a carbon tetrachloride (CCl(4))-induced liver fibrosis model to measure levels of the MMP9-mediated collagen type III degradation fragment CO3-610 (site of cleavage: KNGETGPQGP), during disease progression and regression, and to investigate a potential prognostic role of the biomarker.

MATERIALS AND METHODS

72 female Sprague-Dawley rats aged 6 months old were injected with CCl(4) twice a week over different periods of time to induce varying degrees of liver fibrosis. After 4, 6 and 8 weeks of treatment, administration of CCl(4) was stopped. The 6- and 8-week treatment groups were left to regress for a further 6 or 12 weeks at which point they were sacrificed and livers removed and sectioned. Liver fibrosis was quantified using Visiopharm software to analyse Sirius red-stained sections. Serum levels of CO3-610 were measured in all animals using an ELISA assay as described by Barascuk et al.1

RESULTS

Quantitative histology revealed total collagen deposition in the liver increased as fibrosis progressed. In animals treated with CCl(4) for 4 weeks, collagen comprised on average 4.94% of the total tissue in liver sections, while after 6 weeks the mean was 8.25%, and after 8 weeks, 9.11%. During the regression phase, the total collagen deposition gradually decreased to a mean of 6.9% and 5.09% for animals regressing 6 and 12 weeks respectively after 6 weeks treatment, and 6.27% for animals regressed 12 weeks after 8 weeks treatment. CO3-610 values increased progressively in rats treated for 4 weeks (by a mean of 55.0 ng/ml), 6 weeks (mean 61.1 ng/ml) and 8 weeks (mean 70.2 ng/ml). During the regression phase, CO3-610 values rapidly decreased by a mean of 28.9 ng/ml at 6 weeks and 21.6 ng/ml at 12 weeks in animals previously treated for 6 weeks, and by a mean of 19.52 ng/ml in animals treated for 8 weeks and regressed for 12 weeks. CO3-610 levels were statistically significantly correlated with total collagen during disease progression (r = 0.5701, P < 0.0001). No statistically significant correlation was observed during regression (r = 0.2081, P = 0.1138).

CONCLUSION

Levels of the MMP-9 generated fragment of collagen type III, CO3-610, correlated with the degree of liver fibrosis in rats during the progression phase, but were not correlated with total collagen levels during regression. CO3-610 seems to be produced only under the CCL(4) stimulus, and signifies CO3-610 as a potential marker of progression rather than regression. The corresponding steep elevations in levels of CO3-610 total collagen and collagen type III during liver fibrosis progression underline a potential prognostic capacity of the biomarker.

Vitamin D and nutritional status are related to bone fractures in alcoholics

BACKGROUND

Bone fractures are common in alcoholics.

AIMS

To analyse which factors (ethanol consumption; liver function impairment; bone densitometry; hormone changes; nutritional status, and disrupted social links and altered eating habits) are related to bone fractures in 90 alcoholic men admitted to our hospitalization unit because of organic problems.

METHODS

Bone homoeostasis-related hormones were measured in patients and age- and sex-matched controls. Whole-body densitometry was performed by a Hologic QDR-2000 (Waltham, MA, USA) densitometer, recording bone mineral density (BMD) and fat and lean mass; nutritional status and liver function were assessed. The presence of prevalent fractures was assessed by anamnesis and chest X-ray film.

RESULTS

Forty-nine patients presented at least one fracture. We failed to find differences between patients with and without fractures regarding BMD parameters. Differences regarding fat mass were absent, but lean mass was lower among patients with bone fracture. The presence of fracture was significantly associated with impaired subjective nutritional evaluation (χ² = 5.79, P = 0.016), lower vitamin D levels (Z = 2.98, P = 0.003) and irregular eating habits (χ² = 5.32, P = 0.02). Reduced lean mass and fat mass, and altered eating habits were more prevalent among patients with only rib fractures (n = 36) than in patients with multiple fractures and/or fractures affecting other bones (n = 13). These last were more closely related to decompensated liver disease. Serum vitamin D levels showed a significant relationship with handgrip strength (ρ = 0.26, P = 0.023) and lean mass at different parts of the body, but not with fat mass. By logistic regression analysis, only vitamin D and subjective nutritional evaluation were significantly, independently related with fractures.

CONCLUSION

Prevalent fractures are common among heavy alcoholics. Their presence is related more closely to nutritional status, lean mass and vitamin D levels than to BMD. Lean mass is more reduced, nutritional status is more impaired and there is a trend to more altered eating habits among patients with rib fractures, whereas multiple fractures depend more heavily on advanced liver disease.

Vitamin D supplementation has minor effects on parathyroid hormone and bone turnover markers in vitamin D-deficient bedridden older patients

OBJECTIVES

to evaluate the effects of vitamin D supplementation on parathyroid function and bone turnover in aged, chronically immobile patients.

DESIGN

a randomised double-blind controlled trial.

SUBJECTS

two hundred and eighteen long-term inpatients aged over 65 years.

INTERVENTION

the patients were randomised into treatment groups of I-III, each receiving 0 IU, 400 IU and 1200 IU cholecalciferol per day, respectively. In case of inadequate consumption of dairy products, patients received a daily calcium substitution of 500 mg.

MEASUREMENTS

plasma concentrations of 25-hydroxyvitamin D (25-OHD), intact parathyroid hormone (PTH), amino-terminal propeptide of type I procollagen (PINP), a marker of bone formation, and carboxy-terminal telopeptide of type I collagen (ICTP), a marker of bone resorption, were measured at baseline and after 6 months.

RESULTS

the patients (age 84.5 years) were chronically bedridden. The baseline 25-OHD was low (23 nmol/l), correlated inversely with PINP, and tended to associate inversely with PTH. The prevalence of vitamin D deficiency (VDD) (25-OHD < 50 nmol/l) was 98% and PTH was elevated in 23% of the patients. Vitamin D supplementation significantly increased 25-OHD concentrations (124% group II, 204% group III) and decreased PTH (-7% group II, -8% group III). PINP tended to decrease, but ICTP tended to increase, and only their ratio decreased significantly. The tendency of ICTP to increase was inconsistent. Changes in 25-OHD correlated inversely with those in PTH and PINP.

CONCLUSIONS

vitamin D supplementation has minor effects on PTH and bone turnover in chronically immobilised aged patients with VDD. Further comparative studies and meta-analyses are warranted to elucidate the confounding effects of different mobility levels on the benefits of vitamin D supplementation in patients with differing baseline PTH levels.

Potential use of collagen and elastin degradation markers for monitoring liver fibrosis in schistosomiasis

Liver fibrosis is a serious complication of schistosomiasis infection, is associated with increased amounts of collagen and the collagen cross-link, pyridinoline. Non-invasive markers of liver fibrosis have been developed. Serum and urinary markers of collagen synthesis and degradation have been studied to assess the balance between collagen synthesis, measured with markers of collagen synthesis such as amino-terminal propeptide of type III procollagen (PIIINP), and markers of degradation such as pyridinoline or pyridinoline cross-linked carboxyterminal telopeptide of type I collagen (ICTP). It has been shown that mice infected with Schistosomiasis mansoni excrete excess pyridinoline cross links in urine and this was correlated with the collagen content of granulomas from the liver. Treatment of infected mice with an anti-parasitic drug, praziquantel, decreased the collagen content of parenchyma and excretion of pyridinoline in the urine. Although the connective tissue protein, elastin, is present in the liver, the role of elastin in liver fibrosis has not been investigated. However, it has been shown that the urinary concentration of elastin specific crosslinks, desmosine and isodesmosine, as well as the urinary concentration of the collagen crosslink, pyridinoline, correlated well with liver fibrosis score in biopsy specimens from patients with liver disease secondary to hepatitis C virus and alcohol. Each biopsy specimen was reviewed by two pathologists who were blinded as to the clinical data. The pathological evaluation generated scores for both inflammation and fibrosis. No correlation was seen between the urinary markers and inflammation scores. The measurement of non-invasive markers of collagen synthesis and degradation may be useful in monitoring the reversal of fibrosis following therapeutic intervention in schistosome infections.

Immunochemical characterization of assay for carboxyterminal telopeptide of human type I collagen: loss of antigenicity by treatment with cathepsin K

The assay for the cross-linked carboxyterminal telopeptide of type I collagen (ICTP) has been shown to reflect increased type I collagen degradation in such pathological conditions as bone metastases and rheumatoid arthritis, but to be rather insensitive to the changes in physiological bone collagen turnover (e.g., induced by estrogen or bisphosphonate treatment). To determine the reasons for this discrepancy we localized the antigenic determinant recognized by the ICTP assay and studied the effects of two major osteoclastic proteinases, cathepsin K (EC 3.4.22.38) and matrix metalloproteinase-9 (MMP-9; gelatinase B; EC 3.4.24.35), on immunoreactivity. The antigenic determinant was shown to reside within the hydrophobic phenylalanine-rich regions of the carboxyterminal telopeptides of the two alpha1 chains of human type I collagen, situated between the triple helical domain and the lysine-derived trivalent cross-link. This conclusion was based on differences between the amino acid sequences and cross reactivities of the corresponding human and bovine antigens before and after proteolytic treatments with chymotrypsin. A trivalent cross-link is necessary for providing such a structure, because the divalently cross-linked and monomeric natural and synthetic peptides from the same region, but containing only one phenylalanine-rich sequence, showed poor immunoreaction. Recombinant human cathepsin K cleaved the trivalently cross-linked ICTP structure at two sites between the phenylalanine-rich region and the cross-link, destroying the reactivity with ICTP antibodies. On the contrary, the treatment of isolated ICTP by the matrix metalloproteinases MMP-9 (gelatinase B), MMP-1 (collagenase 1), or MMP-13 (collagenase 3) had no effect on the immunoreaction. Our results indicate that the increased circulating concentrations of ICTP found in several clinical situations are most likely produced by matrix metalloproteinases, whereas cathepsin K-mediated, osteoclastic bone resorption destroys ICTP antigenicity.

Time-dependent changes of serum carboxy-terminal peptide of type I procollagen and carboxy-terminal telopeptide of type I collagen concentrations in patients with acute myocardial infarction after successful reperfusion: correlation with left ventricular volume indices

To test the hypothesis that in patients with acute myocardial infarction (AMI), changes in the concentrations of the serum carboxy-terminal peptide of type I procollagen (PICP) and the carboxy-terminal telopeptide of type I collagen (ICTP) reflect extracellular matrix reformation and degradation, respectively, in the infarct healing processes, we measured these serum concentrations by RIA and compared their values with left ventricular (LV) indices obtained by left ventriculography. We studied 13 consecutive patients with their first AMI who underwent successful reperfusion. Blood samples were taken the day of admission and on days 2, 3, 4, 5, 7, and 14. LV volume indices were determined at 1 month after AMI, when LV remodeling was almost completed. The serum concentrations of both PICP and ICTP changed in a time-dependent manner. The average serum PICP concentration was lower than 1 SD below the mean control values on days 2 and 3 and increased thereafter, returning to the lower end of the control range at day 14. The area under the curve (AUC) for PICP was significantly correlated with the LV end systolic (ES) and end diastolic (ED) volume indices and LV ejection fraction for the first 14 days after AMI. The serum PICP on days 5–14 was inversely correlated or tended to be correlated with the LVES and LVED volume indices. The average serum ICTP concentrations on admission were within the control range, began to increase on day 2, and reached maximal concentrations on day 5, remaining at a plateau concentration until day 14. Although the AUC of ICTP for 14 days, the ICTP concentrations on days 1 and 14, and the minimal and maximal concentrations were significantly correlated with creatine kinase (CK) release and the period from AMI onset to the peak CK time, the concentrations were not significantly correlated with any LV indices except for the concentration on day 4, which was weakly correlated with the LVES volume index. The serum concentrations of PICP showed a significant time-dependent change that correlated with LV indices, indicating that PICP may provide additional information for evaluating the healing process because it affects LV remodeling after AMI. Although the serum concentration of ICTP changed in association with CK release, the ICTP concentration was found to be a poor indicator for LV indices.

Circulating type I collagen degradation products: a new serum marker for clinical severity in patients with scleroderma?

Systemic sclerosis (SSc; scleroderma) results in the excessive deposition of extracellular matrix components in affected organs. This is partly due to enhanced synthesis; however, the role of degradative processes in this disease is still poorly understood. Sera of 32 patients with SSc (22 with the diffuse, 10 with the limited form) and of six patients with morphoea were assessed using radioimmunoassays for the cross-linked carboxy terminal telopeptide of type I collagen (ICTP) and for the amino terminal propeptide of type I procollagen (PINP) reflecting type I collagen degradation and synthesis, respectively. In 27 of the 32 patients with SSc, the concentration of ICTP was above the upper limit of the normal value (4.6 micrograms/L) and the mean level was clearly elevated at 7.92 micrograms/L. The ICTP concentration correlated with the skin score measuring the extent of the lesions, whereas no such correlation was found for PINP. The ICTP antigen in serum, studied by immunoblotting, had a molecular weight of about twice that of the trypsin-generated fragment isolated from human bone collagen. The mean concentration of serum PINP was 43.9 micrograms/L and no patient exceeded the upper limit of the normal range (80 micrograms/L). We report here for the first time that the concentration of the type I collagen degradation product ICTP in serum shows a close correlation with the extent of skin fibrosis in patients with SSc. We conclude that the increased deposition of type I collagen in this disease is accompanied by an increased turnover of this molecule, indicating a more complex derangement of synthetic and degradative processes than previously acknowledged.

Biochemical markers of bone metabolism in draught and warmblood horses

Concentrations of the cross-linked carboxyterminal telopeptide of type I collagen (ICTP) and osteocalcin (OC) have been determined in the serum of one hundred clinically healthy adult Draught or Warmblood horses. The correlation between these two markers has been evaluated and the influence of gender, age and type of horse described. No significant variations were observed between animals of different sex, but a significant inverse correlation (P < 0.0001) with age was observed for both measured parameters. After correction for age, serum levels of OC were found to be lower in Draught [adjusted least square mean (LSM) = 6.612 micrograms.L-1] than in Warmblood horses (adjusted LSM = 8.596 micrograms.L-1), whereas levels of ICTP were higher in Draughts (adjusted LSM = 8.035 micrograms.L-1) than in Warmbloods (adjusted LSM = 6.643 micrograms.L-1). A significant correlation (P < 0.0001) was observed between OC and ICTP. This correlation was stronger if the type of horse was taken into account in the statistical model. The ratio OC:ICTP was independent of gender and age. A higher OC:ICTP ratio in Warmbloods compared to the Draught horses might reflect a higher bone remodelling level of horses submitted to regular daily work. It was concluded that ICTP and OC are influenced by the type of horse, and probably reflect a physiological difference in bone remodelling between these animals.

Clinical evaluation of the Serum CrossLaps One Step ELISA, a new assay measuring the serum concentration of bone-derived degradation products of type I collagen C-telopeptides

The Serum CrossLapsTM One Step ELISA is a sandwich assay using two monoclonal antibodies specific for a β-aspartate form of the epitope EKAHDGGR derived from the carboxy-terminal telopeptide region of type I collagen α1-chain. Our objective was to assess the clinical value of the Serum CrossLaps assay for monitoring antiresorptive therapy in osteoporosis treatment. Samples obtained from postmenopausal women treated with different doses of cyclic or continuous hormone replacement therapy (HRT) with an estrogen analog (tibolone) or with a bisphosphonate (ibandronate) were measured in the Serum CrossLaps One Step ELISA at baseline and at various time points during therapy. The corresponding urine samples were measured in the urine CrossLapsTM ELISA and corrected for creatinine excretion. The serum CrossLaps measurements and corresponding urinary CrossLaps measurements were highly correlated (r &gt;0.8 for all studies). The serum and urine CrossLaps measurements showed a significant decrease among the women treated with clinically relevant doses of either of the antiresorptive agents. Furthermore, the annual percentage change in bone mineral density (BMD) correlated with the measured changes in CrossLaps concentration. The serum CrossLaps assay showed a specificity of 83–100% and a sensitivity of 59–83% for assessing BMD changes. The corresponding values for the creatinine-corrected urinary measurements were 83–92% specificity and 68–79% sensitivity. We conclude that performance of the convenient Serum CrossLaps One Step ELISA is at least equivalent to that of the urine text for follow up of antiresorptive treatment in osteoporosis. Further studies are needed to optimize its use in this and other clinical applications.

Monitoring of extracellular matrix metabolism and cross-linking in tissue, serum and urine of patients with chromoblastomycosis, a chronic skin fibrosis

BACKGROUND

Chromoblastomycosis is a fungal disease leading to a granulomatous reaction associated with dermal fibrosis.

METHODS

In an attempt to elucidate the mechanisms leading to improvement in the cutaneous lesions after treatment with terbinafine, a new antifungal drug, we analysed collagen content and cross-linking before and at the end of the treatment. The turnover of extracellular matrix was monitored for 1 year by following up serum and urinary metabolites.

RESULTS

The serum levels of type III collagen and its N-terminal propeptide were correlated with the lesion size (P < 0.035) after 4 and 12 months of treatment respectively. After 4 months of treatment, urinary pyridinoline was higher (P = 0.04) in patients whose lesion size was reduced by more than 50% and serum hyaluronan was lower in patients who had lesions active for less than 5 years (P < 0.05). The treatment increased pyridinoline and pentosidine cross-links in the lesions but significantly reduced the collagen content (P = 0.05).

CONCLUSION

This is the first demonstration that, in addition to its fungicidal activity, terbinafine acts in vivo as an antifibrotic drug.

Urinary excretion of the collagen cross-link pyridinoline increases during liver fibrogenesis

BACKGROUND/AIMS

Pyridinoline, a specific cross-link of mature collagen, increases in liver during fibrogenesis and its hepatic level is related to the degree of reversibility of the fibrotic process. Since pyridinoline is excreted in urine, we have investigated the relationship between its urinary level and liver fibrogenesis in a model of mild and reversible liver fibrosis, murine schistosomiasis.

METHODS

Pyridinoline was measured by HPLC in urine and in liver of Schistosoma mansoni-infected mice during the acute and the chronic phases of the infection. Collagen deposition was measured colorimetrically. Both the isolated granulomas and the surrounding liver parenchyma were analyzed.

RESULTS

In infected mice, pyridinoline increased mainly in the isolated granulomas, corresponding to the fibrotic lesions, and slightly in the surrounding parenchyma. The urinary excretion of pyridinoline increased during liver fibrogenesis and was correlated to the duration of infection (r=0.81) and to the collagen content of granulomas (r=0.81). The treatment of infected mice by praziquantel, an antiparasitic drug, did not lead to significant changes in liver collagen cross-linking by pyridinoline either in granulomas or in parenchyma. The major effect of the drug was targeted at the collagen content of parenchyma, which decreased by 50%, 18 weeks after treatment. The urinary level of pyridinoline of treated mice was negatively correlated to the length of the treatment follow-up (r=-0.76).

CONCLUSIONS

The measurement of the urinary excretion of pyridinoline could be helpful to monitor the remodeling of liver extracellular matrix occurring in fibrogenesis and the effect of chemotherapy.