Serum hyaluronate and type III procollagen aminoterminal propeptide concentration in chronic liver disease. Relationship to cirrhosis and disease activity

To analyse the relationship between the presence of liver cirrhosis and hepatic inflammation and the serum concentrations of the aminoterminal propeptide of procollagen type III (P-III-NP) and of hyaluronic acid (HA) in chronic liver disease, we measured P-III-NP and HA concentrations in paired serum samples from 133 patients with various chronic liver diseases, from 22 patients with acute hepatitis and from 50 healthy age-matched controls. In 24 (of the 133) patients with autoimmune chronic liver disease, follow-up determination was performed during therapeutic treatment with immunosuppressive drugs. Compared with controls P-III-NP concentrations (medians) were significantly elevated in 65% of patients with chronic active hepatitis (P = 0.00097) and in 79% of patients with active liver cirrhosis (P = 0.0126) but not in patients with chronic persistent hepatitis (P = 0.06). Serum concentrations (medians) of HA were increased (P = 0.0058) in 32% of patients with chronic active hepatitis and in 91% of patients with active cirrhosis (P less than 6 x 10(-7)). The difference of HA serum concentrations but not that of P-III-NP serum concentrations in patients with chronic active hepatitis and in patients with active cirrhosis was statistically significant. HA and P-III-NP serum concentrations were significantly elevated in 22 patients with acute hepatitis.(ABSTRACT TRUNCATED AT 250 WORDS)     

Lymphatic clearance of synovial fluid in conscious pigs: the aminoterminal propeptide of type III procollagen

Abstract. The aminoterminal propeptide of type III procollagen (PIIINP) in serum is employed as a direct marker of fibrillogenesis. The balance between local fibrillogenesis and serum PIIINP is governed by the transport and possible degradation en route from tissue to circulation. In conscious pigs, we investigated the transport of PIIINP from the knee cavity into the circulation after intra-articular injection of radiola-belled PIIINP followed by sequential sampling of thoracic duct lymph, serum and urine. Clearance from the joint space was evaluated by external detection of ¹³¹I-HSA, used as co-tracer. Lymph samples were gel filtrated to assess possible lymphatic degradation of the intact PIIINP. ¹²⁵I-PIIINP and ¹³¹I-HSA were found in thoracic duct lymph within 20 min of the intra-articular injection. Both isotopes had a biphasic appearance, with the first peak after 60 min and a larger peak after 150 min. During the 6 h observational period 18% of the injected PIIINP was found in the lymph. Gel chromatography of lymph showed the fast formation of a small fraction with a lower MW than that of PIIINP, which suggests that some degradation of PIIINP may occur through the lymphatics. The half-life of the joint clearance of HSA by bulk flow was assessed to be 8.3 h. The clearance of PIIINP from the joint was estimated to be equal to that of HSA, which indicates that PIIINP leaves the joint space by bulk flow as has been proposed for HSA. Whereas the fractional amount of PIIINP in lymph and blood was lower than that of HSA, in urine the fractional amount of PIIINP was substantially higher than that of HSA. This may be the outcome of a more rapid irreversible degradation of PIIINP than of HSA. We conclude that I) PIIINP is cleared from the joint space by bulk flow; 2) degradation of PIIINP en route to the circulation cannot be excluded, but is less than 10%, and 3) after disappearing from the joint, PIIINP is distributed in body compartments in a ratio different from that of HSA. Our observations suggest that serum PIIINP may be used as a marker of fibrillogenesis in normal organisms.     

Metabolism of the aminoterminal propeptide of type III procollagen in cultures of human proximal tubular cells.

Degradation of the intact form of the aminoterminal propeptide of type III procollagen (PIIINP) has been established in the liver, whereas the col 1 domain of PIIINP is extracted by the kidneys. We used native human PIIINP and col 1 domain of PIIINP to investigate the degradation of PIIINP in cultures of human proximal tubular cells. Normal renal tissue was obtained from the healthy part of kidneys surgically removed and from biopsies from a total of 10 patients. The degradation was characterized by incubation of [125I]-PIIINP followed by gel filtration. We found that in physiological concentrations (4.4 micrograms l-1 and 11.9 micrograms l-1 intact PIIINP was almost totally degraded, but not col 1 domain. High concentrations of PIIINP (20-50 micrograms l-1) had a non-linear, non-monoexponential degradation over time, which suggests several steps. Gel filtration of [125I]-PIIINP after 1 h, 3 h, 6 h and 24 h of incubation confirmed the observation by showing the rapid formation of a high-molecular-weight fraction, followed by the slower formation of a low-molecular-weight fraction. The high-molecular-weight fraction was PIIINP immunoreactive, but not the low-molecular-weight fraction. We conclude that cultures of human proximal tubular cells degrade intact human PIIINP by the formation of high- and low-molecular-weight fractions. Earlier findings that extraction of the PIIINP col 1 domain takes place in the kidneys, cannot be explained by degradation by the proximal tubular cells.     

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.     

Collagen metabolism in normal and complicated pregnancy: changes in the aminoterminal propeptide of type III procollagen in serum

The turnover of type III collagen, a major constituent of the myometrium and the uterine cervix, during pregnancy was evaluated by monitoring serum antigens related to the aminoterminal propeptide of type III procollagen. Their concentration increased markedly towards term in most uncomplicated pregnancies, while their size distribution throughout the pregnancy resembled that seen in the sera of normal healthy persons. In some patients, however, the level remained low, indicating interindividual variation in the release into serum and metabolism of the propeptide. There were no distinct changes during or immediately after vaginal delivery. Values exceeding the reference range for uncomplicated pregnancies were found during weeks 28-37 in patients with pre-eclampsia, essential hypertension, intrahepatic cholestasis of pregnancy or twin pregnancy. Thus, pregnancy should be taken into account when evaluating results of the serum assay for the aminopropeptide and the use of this assay as an indicator of pregnancy complications warrants further study.     

Measurement of aminoterminal propeptide of type I procollagen (PINP) in serum

The aminoterminal propeptide of type I procollagen (PINP) in serum is a sensitive indicator of the synthesis of type I collagen. Four assays are available for PINP, two of them (intact PINP assays) measure the intact propeptide and the other two (total PINP assays) also detect a smaller antigen in serum. In many clinical situations, these assays give similar information, but renal insufficiency increases the concentration of the smaller antigen, influencing both the apparent concentration of PINP and assay calibration. Serum PINP is mostly affected by changes in bone metabolism. In infants and children, the concentration is much higher than in adults. Serum PINP (s-PINP) is a useful indicator of disease activity in Paget's disease of bone, in bone metastases of osteoblastic nature, and in the follow-up of treatment of osteoporosis. The IFCC and IOF recently recommended the use of s-PINP as a reference marker for bone formation in studies concerning fracture risk assessment and treatment response.     

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)     

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.     

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.     

Procollagen type III aminoterminal propeptide as biomarker of host response in severe sepsis

Purpose

The purpose of this study is to test the hypothesis that procollagen type III aminoterminal propeptide (PIIINP) is early elevated in septic episodes and can indicate the acute organ dysfunction/failure characterizing severe sepsis.

Materials and Methods

This prospective study included 107 consecutive septic patients (44 with sepsis, 13 with severe sepsis, and 50 with septic shock) and 45 controls. After blood sampling (within 48 hours after onset of septic episodes), serum was assayed. Patients were followed up, and their disease severity was daily evaluated.

Results

Procollagen type III aminoterminal propeptide (median [range]) increased in patients with sepsis (9.4 [2.2-42.4] ng/mL) compared with controls (3.6 [1.9-4.9] ng/mL; P < .001), exhibiting further significant increase in patients with severe sepsis and septic shock (19.5 [6.0-52.4] and 20.2 [1.8-89.2] ng/mL, respectively; P < .01-.001 vs sepsis). Among biomarkers of host response severity, PIIINP was the sole that was independently associated with severe sepsis/septic shock (P = .01). The area under the receiver operating characteristic curve for PIIINP to predict which patients with sepsis would eventually develop severe sepsis/septic shock was 0.87; the cutoff of 12 ng/mL had sensitivity 82% and specificity 89%.

Conclusions

Increased serum PIIINP can signify severe sepsis/septic shock and predict which patients with sepsis will eventually develop severe sepsis/septic shock, thus representing a biomarker of risk stratification of patients with sepsis.     

Aminoterminal propeptide of type III procollagen: a marker of disease activity in schistosomal patients.

The serum concentration of aminoterminal propeptide of type III procollagen was measured in 44 Egyptian healthy controls and 29 patients with hepatosplenomegaly originating from endemic areas for schistosomiasis in Egypt. Patients were classified into two main groups according to the histopathological pattern of the liver biopsy: patients with active schistosomal liver fibrosis and patients with inactive schistosomal liver fibrosis. Serum aminoterminal propeptide of type III procollagen levels were elevated in most of patients with active fibrosis but not in those with inactive schistosomiasis. From the present work, it is suggested that aminoterminal propeptide of type III procollagen can be used as a marker for active fibrogenesis in patients with schistosomal liver fibrosis.     

Rapid equilibrium radioimmunoassay for the amino-terminal propeptide of human type III procollagen

This is an equilibrium-type radioimmunoassay for the amino-terminal propeptide of type III procollagen (PIIINP), which overcomes the problem of nonparallelism between the standard and human serum samples encountered with earlier assays. Proper selection of antiserum and reaction conditions diminishes interference from degradation products of the propeptide in serum. Because a rapid solid-phase-bound second-antibody step is included, the assay takes only 3 h. The intra-assay and the interassay CVs are both about 5%. In infants and children the concentration of PIIINP in serum closely parallels the growth-velocity curve. For 88 presumably healthy adults, the PIIINP concentration was 1.7-4.2 micrograms/L, about a third that measured with the previously available commercial assay. This is because of lack of inhibition by small Col 1 domain-related degradation products.     

Serum type III procollagen in dilated cardiomyopathy]

A radioimmunoassay study of procollagen type III end protein (PEP) was conducted in the serum of 11 patients with confirmed dilated cardiomyopathy (DCMP) and 9 patients with coronary heart disease. For DCMP patients PEP levels averaged 8.8 +/- 7.9 micrograms/l, for coronary patients 4.4 +/- 1.6 micrograms/l, in donors 1.7 +/- 1.4 micrograms/l. Thus, the difference between DCMP and coronary patients, donors appeared significant (p less than 0.05). PEP concentrations over 4.5 micrograms/l occurred in 54% of DCMP patients. Growing of PEP turned out most substantial in severe disease (circulatory failure stage IIB-III, pulmonary thromboembolism). Determination of PEP is thought valid for laboratory diagnosis of myocardial inflammation and fibrosis. The discussion covers possible causes and mechanisms underlying high production of PEP from the view point of impaired collagen production.     

Simultaneous evaluation of epithelial cell function by CA 125 and stromal cell activity by aminoterminal propeptide of type III procollagen (PIIINP) in ovarian carcinoma

Serum concentrations of CA 125 and the aminoterminal propeptide of type III procollagen (PIIINP) were measured in 50 patients with clinical stage I or II (N = 16) and stage III or IV (N = 34) ovarian carcinoma before and during cytotoxic chemotherapy. Initially pathological concentrations of CA 125 were found in 92% of all patients and 100% of those in clinical stages II, III and IV. The concentration of PIIINP was at pathological levels in 71% of patients. Serum concentrations of CA 125 (P = 0.04) and PIIINP (P = 0.005) were higher in stages III and IV than in stages I and II. Initial concentration of PIIINP, but not of CA 125, was significantly (P less than or equal to 0.001) higher in the 19 patients who died of the malignancy than in the 31 patients alive at the end of the follow-up period. There was a significant inverse correlation (P = 0.01) between the initial PIIINP values and the survival time among patients with a poor prognosis. Initial concentration of CA 125 was of no prognostic value. During the follow-up, the serum concentrations of CA 125 and PIIINP correlated closely with clinical changes in the disease. Either or both of the tumour markers increased or remained at pathological levels before clinical relapse in patients who had initially responded. PIIINP was a more accurate marker (84%) than CA 125 (63%) in this respect. The information obtained from CA 125 and PIIINP concentrations was identical in 65% and complementary in 33% of the patients.(ABSTRACT TRUNCATED AT 250 WORDS)     

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.     

Association of amino-terminal propeptide of type III procollagen and acute myocardial rejection in male patients receiving heart transplantation.

BACKGROUND: The amino-terminal propeptides of type I and III procollagens (PINP and PIIINP) are markers reflecting the status of collagen turnover. We hypothesized that measurement of these serum procollagen propeptides could be used to non-invasively assess acute rejection in heart transplant recipients. METHODS: In heart transplant recipients, endomyocardial biopsy specimens taken at 6 and 12 months after surgery were used for study. PINP and PIIINP were measured postoperatively at 3, 6, and 12 months. RESULTS: A total of 20 male heart transplant patients and seven male control subjects were enrolled. Five patients showed rejection 6 months after transplantation (group 1), while 15 patients showed no rejection (group 2). In group 2 patients, serum PINP and PIIINP levels decreased significantly 6 months after transplantation. In contrast, elevation of serum PINP and PIIINP levels persisted in group 1 patients 6 months after transplantation. At 6 months after transplantation, group 1 patients had significantly higher PIIINP levels than group 2 patients (p=0.025) and controls (p=0.003). After immunosuppressive therapy, all group 1 patients were free of rejection 12 months after transplantation and serial serum PIIINP levels decreased significantly in these patients. CONCLUSIONS: Serum PIIINP levels represent a non-invasive method to reflect the occurrence and resolution of acute rejection.     

Radioimmunoassay of the carboxyterminal propeptide of human type I procollagen

Type I collagen is the most abundant collagen type in soft tissues and the only type found in mineralized bone. We established a rapid equilibrium radioimmunoassay for the carboxyterminal propeptide of human type I procollagen (PICP), to be used as an indicator of the synthesis of type I collagen. We isolated type I procollagen from the medium of primary cultures of human skin fibroblasts, digested the protein with highly purified bacterial collagenase, and purified PICP by lectin-affinity chromatography, gel filtration, and ion-exchange separation on HPLC. The purity of the protein was verified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and by N-terminal amino acid sequencing of its component chains. The final radioimmunoassay was established with polyclonal rabbit antibodies. Material antigenically related to PICP is readily detected in human serum. There is only one form of the serum antigen, its molecular size and affinity to the antibodies being similar to those of the isolated propeptide. Intra- and interassay CVs are 3% and 5%, respectively. Preliminary reference intervals for healthy adults (18 to 61 years of age) are 38-202 micrograms/L for men and 50-170 micrograms/L for women: in men the concentration is inversely related to age. The serum antigen is stable during storage and after repeated thawing.