Collagen peptidase and type III procollagen peptide serum levels in chronic liver diseases.

The concentration of the N-terminal peptide of procollagen III and the activity of collagen peptidase (PZ-peptidase) were measured in sera from 92 patients with chronic liver disease. In patients with liver cirrhosis and chronic hepatitis with transformation of liver structure, high values were found for both variables compared with hepatoses and chronic hepatitis without transformation. The concentration of procollagen III peptide and the activity of collagen peptidase in serum increased with increasing degrees of fibrosis and, even more markedly, with increasing degrees of mesenchymal activity in the liver.     

Radioimmunoassay for type III procollagen peptide and its application to human liver disease

A sensitive and specific radioimmunoassay was developed for the precursor-specific peptide segment located at the amino end of bovine type III procollagen. Human material showed high cross-reactivity in this assay. Two forms of human procollagen peptides were detected in body fluids. The larger peptide (45K) was found in serum and ascites, and resembled the whole precursor-specific segment which is presumably released from human type III procollagen by a single enzymatic cleavage. The smaller peptide (10K) was found mainly in urine indicating that further degradation of circulating procollagen peptides is required prior to their passage through the kidney. Compared to peptide concentrations in normal human serum two to twenty-fold increases were observed in all patients with alcoholic liver disease, in fifteen of seventeen patients with acute hepatitis, and in ten of fourteen patients with chronic active hepatitis. Much higher levels were detected in ascites fluid. Patients with rheumatoid arthritis and other diseases showed far smaller elevations of the serum peptide. In alcoholic liver disease peptide levels correlated well with inflammation and necrosis observed in liver biopsies, but not with other laboratory parameters.     

Evaluation of serum aminoterminal procollagen type III propeptide as an index of portal hypertension and esophageal varices in chronic liver diseases

The concentration of the aminoterminal propeptide of type III procollagen (P-III-P) was determined in serum of cubital vein and hepatic vein of patients with various types of chronic liver diseases (n = 111) and correlated with the portal venous pressure and with the degree of esophageal varices. The P-III-P level in all chronic liver diseases was correlated (rS 0.542, p less than 0.001) with the portal venous pressure, but in liver fibrotic subjects (n = 29) this correlation (rS 0.310) was not significant, in liver cirrhosis (n = 30) the respective correlation was found to be weak (rS 0.333, p less than 0.05) and similar to that in patients with unspecified chronic liver diseases (n = 52) (rS 0.425, p less than 0.01). Sensitivity and specificity of P-III-P at a cut-off concentration of 12 ng/ml for portal hypertension (portal vein pressure 5 mm Hg) are 0.93 and 0.42, respectively, the diagnostic efficiency is 0.67. Predictive values at the same cut-off level of P-III-P and an assumed prevalence of portal hypertension of 50% are 0.62 and 0.85 for the positive and negative test result, respectively. The level of P-III-P is not related to the degree of esophageal varices. The mean P-III-P concentration in the hepatic vein was found to be significantly (p less than 0.001) higher (about 35%) than that in the cubital vein. It is concluded that P-III-P is not an useful parameter for diagnosis of portal hypertension and monitoring of portal vein pressure and of the degree of esophageal varices.     

Serum procollagen type III peptide in chronic hepatitis B

The clinical significance of serum procollagen type III peptide, a marker of active fibrogenesis, was evaluated in 110 hepatitis B surface antigen positive patients with chronic hepatitis (32 chronic persistent hepatitis, 60 chronic active hepatitis, and 18 active cirrhosis), selected on the basis of active viral replication and biochemical activity, including 54 cases treated with interferon-α. At presentation the procollagen type III peptide level serum was above normal in 48 (44%) of the 110 patients and the median value was significantly higher than that of healthy carriers with normal transaminases and histology (P<0.000005). Semiquantitative histological evaluation showed a significant correlation between serum procollagen type III peptide levels and necrosis/inflammation in the subgroup of patients with chronic active hepatitis, but no relationship with the score of fibrosis. Among patients treated with interferon-α and with increased fibrogenic activity (indicated by high pretreatment serum levels of procollagen type III peptide), peptide levels were significantly decreased when pretreatment levels were compared with those at 12 months after therapy withdrawal, both in responders to interferon (P=0.022) and non-responders (P=0.012). However, serum procollagen type III peptide levels normalized in 75% of responders to interferon with sustained serological and histological remission of liver disease, but in only 21% of non-responders (P=0.02). These results obtained in a well-defined population suggest that serum procollage type III peptide is a better marker of active fibrogenesis and inflammation than an indicator of the extent of fibrosis, and that interferon may reduce active liver fibrogenesis in chronic hepatitis B indenpendently of its effect on viral replication. However, a consistent proportion (56%) of our chronic hepatitis B patients had normal serum procollagen type III peptide levels at presentation, thus precluding the clinical use of this marker both for diagnosis of liver injury and for monitoring the therapeutic response to interferon.     

Serum levels of pigment epithelium-derived factor (PEDF) are independently associated with procollagen III N-terminal peptide levels in patients with nonalcoholic fatty liver disease

Objectives

Pigment epithelium-derived factor (PEDF) is a glycoprotein that belongs to the superfamily of serine protease inhibitors with complex anti-oxidative, anti-fibrotic, and anti-inflammatory properties, thus being involved in cardiometabolic disorders. Nonalcoholic fatty liver disease (NAFLD) is a hepatic manifestation of the metabolic syndrome as well. However, the pathophysiological role of PEDF in NAFLD remains largely unknown. We studied here the relationship between serum PEDF levels and various clinical markers of NAFLD in humans.

Design and methods

The study involved 194 biopsy-proven NAFLD patients (102 male and 92 female) with a mean age of 51.3 ± 13.8 years. We examined which anthropometric, metabolic and inflammatory variables, and liver steatosis and fibrosis markers are independently associated with serum levels of PEDF.

Results

Mean serum levels of PEDF were 16.4 ± 5.7 μg/mL. Univariate analysis revealed that age (inversely), male, body mass index, waist circumference, numbers of white blood cells and platelets, aspartate aminotransferase, alanine aminotransferase, fasting plasma glucose, glycated hemoglobin, uric acid, procollagen type III N-terminal peptide (P-III-P), subcutaneous fat areas, visceral fat areas and liver to spleen density ratio in computed tomography, the presence of diabetes and medication for hyperlipidemia were significantly associated with serum levels of PEDF. In multiple stepwise regression analysis, age (p < 0.01, inversely), male (p < 0.05), waist circumference (p < 0.01), white blood cell number (p < 0.05), P-III-P (p < 0.05), and the presence of diabetes (p < 0.05) and medication for hyperlipidemia (p < 0.01), were independently correlated to serum levels of PEDF (R² = 0.285).

Conclusions

The present study reveals that serum levels of PEDF are independently associated with P-III-P levels, suggesting that PEDF level is a novel biomarker of liver fibrosis in patients with NAFLD.     

Serum type III procollagen peptide levels in coronary artery disease (a marker of atherosclerosis)

The known shift in collagen synthesis from procollagen type I to type III in patients with atherosclerosis, suggested measurement of serum procollagen III peptide (PIIIP) levels in patients with coronary artery disease (CAD). Two groups of patients were studied: group I--thirty-six patients with CAD (male, mean age 56.9 +/- 7.5 years, hospitalized for coronary angiography. Risk factors included 16 patients with high blood pressure, four diabetics, 31 smokers and 15 with hypercholesterolaemia. Five patients had no significant lesions, seven had one vessel with over 50% stenosis, 10 had two vessels and 14 had three vessels. Group II--35 patients (male, mean age 39.4 +/- 13.3 years), with normal physical examination and ECG according to WHO criteria, formed the control group: the risk factors included nine patients with high blood pressure, 14 smokers and one with hypercholesterolaemia. Procollagen III peptide levels were determined by radioimmunoassay. In group I, PIIIP levels were 26.8 +/- 16 ng ml-1 vs. 10.4 +/- 3.2 for group II. Sixty-one per cent of group I had pathological levels of PIIIP with an absence of correlation with the severity of atherosclerosis or risk factors. Only 2.8% of patients in group II had pathological levels. Procollagen III peptide determination would appear to be a sensitive, specific and predictive test for atherosclerosis in patients with CAD.     

Cryptogenic chronic active liver disease. Evaluation of serum aminoterminal peptide of type III procollagen as a marker of histological activity

Summary Sera from 64 patients with HBsAg-negative chronic liver disease with or without cirrhosis were investigated for aminoterminal peptide of type III procollagen (sP-III-P) as a suitable marker of hepatic fibrosis; 244 healthy control subjects were included in the study. A close correlation (p<0.01) between sP-III-P levels and histological activity was observed; on the contrary, no correlation was found between the same serum marker of liver fibroplasia and biochemical activity or clinical severity of the disease. We conclude that sP-III-P as a suitable marker of liver overload of collagen fibers is strongly correlated with the histological activity of the disease. Local immune reactions produce soluble substances that might stimulate fibroblastic activity. The test has a significant sensitivity and a very high specificity as a marker of chronic liver disease with histological activity.     

Estimation of the production rates of serum aminoterminal propeptide of type III procollagen and laminin in human fibrotic liver

The concentrations of laminin, a high molecular weight non-collagenous glycoprotein of basement membranes, and of the N-terminal propeptide of type III procollagen were determined in the serum of the liver outflow vascular region (hepatic vein) and of a peripheral vein (cubital vein) in patients with chronic liver diseases (fibrosis, cirrhosis, unspecified histology; n = 173), in order to determine their secretion rates from the injured livers. The mean levels of laminin (1.84 kU/l) and of procollagen peptide (28.0 micrograms/l) in hepatic vein were significantly higher (about 9.5% at p less than 0.02, and 37% at p less than 0.001, respectively) than those in the periphery (1.68 kU/l and 20.4 micrograms/l, respectively). In chronic liver diseases, however, laminin and procollagen peptide concentrations in the hepatic vein were lower than or equal to those in the cubital vein in 18% and 27% of patients, respectively. The highest regional differences of the concentrations were noted in cirrhotic subjects. The serum levels of laminin (rs 0.93) and of procollagen peptide (rs 0.73) in hepatic and in cubital vein are highly positively correlated (p less than 0.001), but the levels of procollagen peptide in hepatic vein are only weakly but still significantly statistically related with those of laminin (rs 0.446, p less than 0.001). Similarly, the hepatic-cubital venous concentration differences of both proteins are weakly (rs 0.312) but significantly (p less than 0.001) correlated. On the basis of several assumptions we estimated secretion rates from the livers of 120 U.min-1 for laminin, and 5.7 micrograms.min-1 for procollagen peptide.(ABSTRACT TRUNCATED AT 250 WORDS)     

慢性肝病患者血清精氨[基]琥珀酸裂合酶的变化

目的建立自动生化分析仪检测血清精氨[基]琥珀酸裂合酶（ASL）的方法,探讨其对慢性肝病的诊断效能。方法测定149例慢性肝病患者、247例非肝病患者和32例健康对照血清ASL活性,同时测定ALT和AST活性。结果本组病例ASL、ALT和AsT水平与健康对照间均存在明显差异;对照组与非肝病患者ASL活性无明显差异（q=0．051,P=0．959）;慢性肝病组与非肝病组、健康对照组ASL活性无重叠。ROC曲线显示ASL对判断慢性肝病的敏感性为98．7％,特异性为97．5％（cutoff值=9．2U／L）;ALT、AST的敏感性为60．4％和57．7％,特异性仅分别为33．4％和36．6％（cutoff值：40．0U／L）。结论ASL诊断慢性肝病的敏感性和特异性均优于AsT和ALT,是慢性肝病诊断的有用指标。     

Aminoterminal procollagen III peptide elevation in alcoholics who are selenium and vitamin E deficient

Serum aminoterminal procollagen III peptide (PIIIP) was measured in 36 alcoholic subjects. There was a significant elevation of PIIIP in subjects with proven liver disease (median 17.5 ng/ml, n = 24) compared to those without liver disease (median 4.7 ng/ml, n = 12). Those subjects with raised serum transaminase values (AST) had elevated PIIIP values (median 13.7 ng/ml, n = 22) compared to those with normal transaminase values (median 3.7 ng/ml, n = 14). In those alcoholic subjects who were deficient in both selenium and vitamin E there was a significant elevation (p less than 0.01) of PIIIP values (median 26.4 ng/ml, n = 7) compared to subjects with normal levels (median 7 ng/ml, n = 11). Subjects deficient in selenium alone had PIIIP values in an intermediate range. Selenium and vitamin E, as important free radical scavengers, may protect the liver in alcoholic subjects from oxidative damage leading to hepatic fibrosis.     

Low levels of serum type III procollagen aminoterminal propeptide confirmed type III collagen deficiency in patients without typical clinical symptoms of Ehlers-Danlos type IV

Biochemical analysis of skin samples revealed that the content of type III collagen was greatly reduced in several subjects with joint hypermobility, stretchability and bruisability of skin. When cultured dermal fibroblasts were found to secrete decreased amounts of type III procollagen into medium (about 30-45% the normal amount) and serum type III procollagen aminopropeptide levels were significantly lower than normal values (P less than 0.001). The abnormalities in type III procollagen are in keeping with Ehlers-Danlos type IV although the clinical findings in our patients are not normally associated with this disorder. The results illustrate the clinical heterogeneity of Ehlers-Danlos type IV and the importance of biochemical analysis, such as determination of type III procollagen aminopropeptide levels, to check type III collagen metabolism especially if there is no family history and if correct diagnosis is not reliable by clinical examination alone.     

Type III procollagen is a reliable marker of ARDS-associated lung fibroproliferation

Purpose

A specific biomarker of post-ARDS fibroproliferation could be useful in the identification of patients who could benefit from therapies aiming to modulate fibroproliferation such as corticosteroids.The aim of this prospective study was to determine the best threshold of the N-terminal-peptidetype III procollagen (NT-PCP-III) in non-resolving ARDS to validate this threshold according to the outcome.

Methods

Concerning the best threshold of NT-PCP-III, all consecutive patients with a non-resolving ARDS were included if all the following criteria were fulfilled: moderate to severe ARDS lasting for at least 5 days, lung biopsy performed, serum and alveolar NT-PCP-III obtained within 1 week prior to biopsy, and no documented infection contra-indicating the corticosteroids. In the validation cohort part of the study, patients were included at day 7 if they presented a persistent moderate to severe ARDS.

Results

Nineteen of 32 patients had fibroproliferatio nonbiopsy. Serum and alveolar NT-PCP-III were higher in patients with fibroproliferation. Using a threshold of 9 µg/L, alveolar NT-PCP-III had the highest accuracy for diagnosing fibroproliferation (sensitivity = 89.5 % and specificity = 92.3 %). Regarding the 51 patients included in the validation cohort, the mortality rate at day 60 was increased in patients presenting an alveolar NT-PCP-III level higher than 9 µg/L (69 vs. 17 %, p < 0.001). The mean alveolar level of NT-PCP-III on day 7 was 8.1-fold higher in nonsurvivors (p = 0.03).

Conclusions

The determination of NT-PCP-III on BAL done at day 7 in persistent ARDS is able to identify patients with fibroproliferation who could be included in a trial of corticosteroids or any other treatment that might help resolve lung fibroproliferation.

     

Serum concentrations of laminin and aminoterminal propeptide of type III procollagen in relation to the portal venous pressure of fibrotic liver diseases

In sera of patients with fibrotic liver diseases (n = 33) classified histologically into various degrees of liver fibrosis (n = 21) and cirrhosis (n = 12) the concentrations of the basement membrane protein laminin and of its pepsinresistant fragment P1 and of the N-terminal propeptide of type III procollagen were determined. The concentrations of both proteins were related to the portal venous pressure measured in these patients. Compared with the reference population (n = 146) the concentration of laminin increases from 1.04 U/ml (normal persons) to 1.69 +/- 0.46 U/ml in liver fibrotic and 2.58 +/- 0.87 U/ml in liver cirrhotic patients. Although the concentrations of the propeptide of type III procollagen increase also there exist only weak correlations between both connective tissue proteins in serum. Laminin is correlated highly positive with the portal venous pressure in cirrhotic subjects (r = 0.9206), the extent of laminin elevation reflects closely the degree of portal hypertension. Virtually all of the fibrotic patients having a laminin concentration within the reference range had a normal portal venous pressure. The data suggest laminin as a potentially useful parameter for monitoring the portal venous pressure in cirrhotic and severe fibrotic patients.     

Increased serum levels of macrophage migration inhibitory factor in alcoholic liver diseases and their expression in liver tissues.

OBJECTIVES: To study the role of macrophage migration inhibitory factor (MIF) in the pathogenesis of alcoholic liver diseases. DESIGN AND METHODS: The levels of MIF in the sera were estimated by an enzyme-linked immunosorbent assay in 13 patients with alcoholic hepatitis (ALH), 9 patients with alcoholic cirrhosis (ALC) and 26 normal controls. MIF was localized in the liver specimens by immunohistochemistry. RESULTS: The mean levels of MIF in the sera were significantly higher in ALH and ALC compared with the normal controls (p < 0.05). Serial observations revealed a relationship between serum MIF levels and the serum transaminase levels. MIF was expressed by the hepatocytes and by the infiltrating cells around the site of accumulation of neutrophils and ballooned hepatocytes in ALH. CONCLUSIONS: This is the first report on MIF in human alcoholic liver diseases, and the data suggest that MIF may be related to abnormal cytokine homeostasis in ALH.     

N-terminal procollagen peptide and beta 2-microglobulin in synovial fluids from inflammatory and non-inflammatory joint diseases

The concentrations of NH2-terminal procollagen peptide were determined radioimmunologically in synovial fluids from inflammatory and non-inflammatory joint diseases. The mean concentrations +/- SD were 1.39 +/- 0.77 and 1.13 +/- 0.63 mg/l and, hence, did not reveal significant differences. Compared with serum, peptide levels in synovial fluids are 10(3) times higher. No statistical correlation was found between procollagen peptide levels and the concentrations of beta 2-microglobulin, a suggested parameter of disease activity, and other established indicators (total protein, total and differential cell count) of inflammatory activity.