Is the aminoterminal propeptide of type III procollagen degraded in the liver? A study of type III procollagen peptide in serum during liver transplantation in pigs

The aminoterminal propeptide of type III collagen was monitored in serum during liver transplantation in nine pigs. The aim was to investigate whether removal of the liver causes any changes in the serum concentration of the propeptide. Another connective tissue component, hyaluronan, a glycosaminoglycan known to be degraded in the liver endothelial cells, was also measured. Removal of the liver caused a significant increase in the concentration of the intact propeptide as well as of hyaluronan. Gel filtration confirmed the increase in the amount of intact propeptide. However, another large propeptide-related antigen, eluted near the void volume, appeared in the antigen profile during the anhepatic phase. This peak probably represents the propeptide still attached to the collagen molecule (pN collagen). The findings indicate that the liver is involved in the degradation of the propeptide and of larger propeptide-holding proteins.     

Serum type III procollagen propeptide levels in acromegalic patients

Serum type III procollagen propeptide (PIIIP) is a reliable index of tissue collagen synthesis. Since in acromegaly there is increased collagen production, we measured serum PIIIP in acromegalic patients before any treatment (basal), during medical treatment with the somatostatin analog SMS 201-995, and after pituitary adenomectomy. In all patients, serum GH and plasma somatomedin-C (SmC) levels were also measured. Basal serum PIIIP levels were significantly (P less than 0.01) higher in acromegalic patients (mean +/- SEM, 22.7 +/- 2.1 ng/ml) than in normal subjects (n = 30; 9.7 +/- 0.5 ng/ml), and they were significantly correlated with plasma SmC values (r = 0.31; P less than 0.05). A significant (P less than 0.01) reduction in PIIIP levels occurred in patients treated with SMS 201-995 or surgery (from 24.3 +/- 2.7 to 12.4 +/- 1 ng/ml) as well as in GH and SmC levels. The maximum percent decrease in serum PIIIP was significantly correlated with those in GH (r = 0.65; P less than 0.01) and SmC (r = 0.60; P less than 0.01). Serum PIIIP levels did not change in those patients in whom neither GH nor SmC were decreased by treatment. In conclusion, serum PIIIP levels are elevated in acromegalic patients, and they decline in parallel with GH and SmC during medical or surgical treatment. Serum PIIIP measurements may be useful in the evaluation of acromegalic patients to gain information on the biological activity of GH and in monitoring the course of the disease.     

Serum concentrations of aminoterminal propeptide of type III procollagen and propeptide of human type I procollagen in systemic lupus erythematosus

The purpose of this study was to assess the association between the serum levels of aminoterminal propeptide of type III procollagen (PIIINP) and carboxyterminal propeptide of type I procollagen (PICP) with disease activity and damage in systemic lupus erythematosus (SLE). Thirty-three patients with SLE were compared with 31 controls. The assessment in SLE included disease activity indices (SLEDAI, MEX-SLEDAI) and damage index (SLICC/ACR). PIIINP and PICP were measured by radioimmunoassay. Compared with controls, mean levels of PIIINP were higher in SLE (2.9±1.8 vs. 1.8±1.2, P=0.006). PICP was also increased in SLE versus controls (163±94 vs. 102±62, P=0.007). PIIINP was correlated with SLICC/ACR (r=0.33, P=0.048). No correlation was observed between PICP and PIIINP with other clinical or therapeutic variables. These preliminary data suggests a role of PIIINP as a marker for chronic damage. Follow-up studies are required to evaluate its utility in predicting future damage.     

Aminoterminal propeptide of type III procollagen and hyaluronan in patients with primary biliary cirrhosis: Markers of fibrosis in primary biliary cirrhosis

The aminoterminal propeptide of type III procollagen (PIIINP) and hyaluronan have previously been studied in different liver diseases. The results of these studies are controversial. The aim of the present study was to examine the relationship between PIIINP and hyaluronan levels and the clinical, biochemical and histological features of primary biliary cirrhosis (PBC) and its prognosis. Fifty-five PBC patients were studied at the time of diagnosis of PBC and were followed up for a mean of 58 months. During the follow-up period 21 patients died. In addition, 30 healthy subjects were examined in the present study. Hyaluronan and PIIINP were measured by radioimmunoassay and the levels of both PIIINP and hyaluronan were higher in PBC patients than in healthy volunteers (P< 1.8 times 10^-6 and 1.6 times 10^-9, respectively). Hyaluronan and PIIINP levels were above normal values in 82 and 84% of PBC patients, respectively. There were correlations between PIIINP and hyaluronan and the histological stage of PBC (r=0.44, P< 0.004 and r=0.56, P< 0.00001, respectively). The correlation between PIIINP and hyaluronan was 0.46 (P< 0.0035). In symptomatic patients, both PIIINP and hyaluronan values were higher than in controls (P< 0.002 and P< 0.006, respectively). The levels of PIIINP correlated significantly with bilirubin (r=0.43, P< 0.006), while hyaluronan was correlated with age (r=0.33, P< 0.015), pruritus (r=0.32, P< 0.02), fatigue (r=0.41, P< 0.003), hepatomegaly (r=-0.46, P< 0.0008), the presence of oesophageal varices (r=0.34, P< 0.002), weight loss (r=0.29, P< 0.05), bilirubin (r=0.54, P< 0.0001), albumin (r=-0.30, P< 0.04), extent of fat excretion (r=0.53, P< 0.009) and length of symptomatic period before diagnosis of PBC (r=0.43, P< 0.002). Using Cox's logistic regression analysis, survival was found to be influenced by bilirubin concentration but not by hyaluronan, PIIINP, age, albumin or histological stage. Therefore, hyaluronan is a more sensitive marker for predicting advanced PBC than is PIIINP. However, neither hyaluronan nor PIIINP gave any indication of prognostic outcome.     

Alpha-interferon improves liver fibrosis in chronic hepatitis C: clinical significance of the serum N-terminal propeptide of procollagen type III

Our objective was to estimate the effect of interferon (IFN) on the evolution of fibrosis in chronic hepatitis C and the significance of the N-terminal propeptide of procollagen type III (PIIIP) as a marker of fibrogenesis. One hundred seventeen patients, 72 male (61%) and 45 female (39%), with a mean age of 40.7 ± 11.9 years were treated with 2b-IFN, 3 to 5 MU, for 12 months: sustained responders (SR = 44), relapsers (RR = 35), and nonresponders (NR = 38). Liver biopsies were performed before treatment and 1 year after cessation of IFN for evaluation of the histological activity index (HAI). Serum PIIIP was obtained at the time of liver biopsy, at the beginning, during, and end of therapy and during the follow-up. The normal value in 29 healthy individuals was 0.37 ± 0.18 U/L. Staging was reduced in 58% of SR, 12.5% of RR, and 11.5% of NR. There was a correlation between PIIIP and the HAI before (n = 71, r _s = 0.41, P < 0.0004) and after IFN (n = 71, r _s = 0.58, P < 0.0001). The SR had a better improvement in grading (90.3%; P < 0.05) and staging (58%; P < 0.001). The correlation of the HAI parameters with the variation of PIIIP showed significance only for fibrosis (r _s = 0.36, P < 0.002) and portal inflammation (r _s = 0.35, P < 0.01). PIIIP normalized only in patients whose fibrosis improved (P < 0.01). At the end of therapy, PIIIP had a predictive value in the distinction of SR from RR (PPV, 64; PNV, 55.6). During the follow-up, PIIIP remained lower in SR compared with RR and NR (P < 0.002). The response to -IFN improved liver inflammation and fibrosis. Serum PIIIP is a useful noninvasive method to evaluate serially fibrogenesis in chronic hepatitis C treated with IFN.     

Splanchnic and renal extraction of circulating type III procollagen aminoterminal propeptide in patients with normal liver function and in patients with alcoholic cirrhosis

Splanchnic and renal extraction of circulating aminoterminal propeptide of type III procollagen and related antigens were studied in 12 patients with normal liver function and in 19 patients with alcoholic cirrhosis during catheterization. Type III procollagen peptide in serum was measured in two assays: the Type III Procollagen Peptide Radioimmunoassay Kit, a new assay that selectively determines the intact propeptide (and larger type III propeptide-holding antigens) and the Type III procollagen Fab assay that measures both the intact propeptide and the smaller fragments that quantitatively dominate in serum. A significant decrease in the concentration of the intact propeptide between the artery and the hepatic vein was found in the group with normal liver function (p less than 0.01) and in patients with cirrhosis (p less than 0.01). In patients with cirrhosis, however, the splanchnic extraction ratio of the intact propeptide (median = 0.04, range = -0.03 to 0.16) was significantly lower than in patients with normal liver function (median = 0.17, range = 0.05 to 0.36, p less than 0.01). The concentration of the intact propeptide in the hepatic vein was positively correlated to hepatic pressure (n = 18, r = 0.51, p less than 0.05) and inversely correlated to indocyanine green clearance (n = 15, r = -0.61, p less than 0.05). No splanchnic extraction could be demonstrated in the Type III propeptide Fab assay. A significant renal extraction was found in the Fab assay, but not in Type III Procollagen Peptide Radioimmunoassay Kit.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of insulin on serum amino-terminal propeptide of type III procollagen in non-insulin-dependent diabetes mellitus.

The effect of insulin on the serum levels of the amino-terminal propeptide of type III procollagen (PIIINP) was investigated in patients with non-insulin-dependent diabetes mellitus, whose disease was unsatisfactorily controlled by oral drugs. Before insulin therapy the PIIINP values of the patients (3.2 +/- 1.3 micrograms/l, n = 38) varied within the range of healthy subjects (3.1 +/- 0.6 micrograms/l, n = 50, NS). Insulin therapy (6-20 IU at bedtime plus the oral drugs) improved the glycemic control and increased the serum PIIINP during a 4 week (3.1 +/- 0.9 to 3.8 +/- 1.1 micrograms/l, P less than 0.01, n = 8) and an 8 week period (3.2 +/- 1.3 to 3.8 +/- 1.6 micrograms/l, P less than 0.001, n = 22). The values were still elevated after 6 months on insulin (3.5 +/- 1.5 to 4.0 +/- 1.7 micrograms/l, P less than 0.01, n = 12). Placebo-insulin did not alter the concentration of PIIINP (3.1 +/- 0.6 to 2.8 +/- 0.6 micrograms/l, NS, n = 8) whereas the glycemic control improved and body weight decreased. The PIIINP values correlated with fasting insulin before (r = 0.403, P less than 0.05, n = 30) and after the therapy (r = 0.452, P less than 0.001, n = 60). Insulin therapy, while correcting the hormone deficiency and restoring glucose and protein metabolism, seems to activate the synthesis of type III procollagen in patients with NIDDM. This may promote the atherosclerotic process.     

Synovial fluid and serum concentrations of aminoterminal propeptide of type III procollagen in healthy volunteers and patients with joint disease.

OBJECTIVES--To analyse synovial fluid and serum concentrations of the amino-propeptide of the type III procollagen (PIIINP) in normal individuals and patients with joint disease, and to explore the relationship between synovial fluid PIIINP concentrations and the rheumatological diagnosis, local inflammation, and joint disease. METHODS--A radioimmunoassay was used to measure the PIIINP concentrations in serum and knee joint synovial fluid from 16 healthy volunteers and patients with osteoarthritis (OA) (n = 40), rheumatoid arthritis (RA) (n = 30), and psoriatic arthritis (PsA) (n = 12). The PIIINP measurements were related to demographic data, synovial fluid leucocyte counts, and radiographic changes at the knee. RESULTS--Serum PIIINP concentrations were greater in each of the disease groups than in control subjects, but there were no differences between the disease groups. Synovial fluid concentrations of PIIINP were much greater than those in serum, indicating local production, and were significantly greater in RA than in other disease groups (p < 0.001). There was only a weak positive correlation between synovial fluid leucocyte counts, some radiographic changes, and synovial fluid PIIINP concentrations. CONCLUSIONS--These data suggest that synovial fluid PIIINP concentrations may reflect local synovial proliferative processes in joint disease, and that they could be of diagnostic and prognostic value in inflammatory arthropathies.     

The serum concentrations of the aminoterminal propeptide of procollagen type III and the hepatic content of mRNA for the alpha 1 chain of procollagen type III in carbon tetrachloride-induced rat liver fibrogenesis.

Serum concentrations of the aminoterminal propeptide of procollagen type III (PIIIP) are elevated in fibrogenic diseases of the liver, but the mechanism of elevation is not fully understood. To investigate the mechanism, we compared serum concentrations of PIIIP with total liver content of mRNA for the pro alpha 1 (III) chain, in rats with carbon tetrachloride (CCl4)-induced liver fibrosis. Adult male rats received CCl4 in mineral oil twice weekly for 8 weeks and were compared with age-matched controls. Serum concentrations of PIIIP were measured by a specific radioimmunoassay; molecular sizes of PIIIP in serum were also determined. Pro alpha 1 (III) mRNA content in the liver was quantitated by RNA slot-blot hybridization and chemical measurement of total hepatic RNA content. Total collagen content of the liver was estimated by hydroxyproline measurement. All CCl4-treated animals had septal fibrosis after 4 weeks, and evidence of cirrhosis (regenerative nodules, ascites) was seen after 7 weeks of treatment. Serum concentrations of PIIIP and pro alpha 1 (III) mRNA content in the liver were correlated well until cirrhosis has established. They increased simultaneously after 3 weeks of treatment, 1 week before any elevation of hepatic hydroxyproline could be detected. After cirrhosis has established, pro alpha 1 (III) mRNA content in the liver decreased markedly, but serum PIIIP levels continued to be elevated. Hepatic hydroxyproline plateaued after 5 weeks. The molecular sizes of serum PIIIP indicate the release of intact native procollagen peptide during the development of cirrhosis. In conclusion, at least in CCl4-induced liver fibrosis in the rats, serum PIIIP levels can be used as a fibrogenic marker for the period progressing to cirrhosis. But the use of the serum PIIIP levels in cirrhosis seems to be limited by factors other than liver fibrogenesis.     

Long-term follow-up of serum N-terminal propeptide of collagen type III levels in patients with chronic liver disease

To evaluate the diagnostic and prognostic significance of the N-terminal propeptide of collagen Type III (Col 1-3) in chronic liver disease, the peptide level was measured in the serum of 4 patients with primary biliary cirrhosis, 5 with chronic persistent hepatitis, 12 with chronic active hepatitis, and 1 with autoimmune hepatitis, for a period of 2 to 10 years and compared with liver function and histology. In primary biliary cirrhosis, Col 1-3 peptide levels were always elevated, regardless of medical therapy; however, after liver transplantation in one patient, the Col 1-3 peptide level decreased. In chronic persistent hepatitis, the peptide level fluctuated around the upper limit of normal. Among patients with chronic active hepatitis, the Col 1-3 peptide level normalized in 2 patients during remission, but was elevated in 7 patients who developed cirrhosis. Only in a patient with autoimmune hepatitis was the Col 1-3 peptide level normal, although the patient developed cirrhosis during prednisone therapy. When prednisone was withdrawn, the Col 1-3 peptide level increased. The data suggest that the serum Col 1-3 peptide may estimate the course of liver fibrosis in chronic liver disease and has prognostic value, particularly in chronic active hepatitis. Persistent elevation suggests ongoing fibrosis and development of cirrhosis; normalization suggests remission.     

Serum concentrations of the carboxyterminal cross-linking domain of procollagen type IV (NC1) and the aminoterminal propeptide of procollagen type III (PIIIP) in chronic liver disease

Serum concentrations of both the carboxyterminal cross-linking domain (NC1) of procollagen type IV and the aminoterminal propeptide of procollagen type III (PIIIP) were measured by specific radioimmunoassays in 60 patients with chronic liver disease and 50 healthy controls. Compared with controls (5.3 +/- 1.3 ng/ml, mean +/- S.D.), NC1 concentrations were significantly elevated in patients with chronic active hepatitis (10.2 +/- 2.0 ng/ml) and liver cirrhosis (13.5 +/- 3.0 ng/ml), but not in chronic persistent hepatitis (6.0 +/- 0.9 ng/ml). The concentrations in patients with active liver cirrhosis were significantly higher than those in patients with inactive cirrhosis. Serum concentrations of PIIIP in controls, parients with chronic persistent hepatitis, chronic active hepatitis and cirrhosis were 5.8 (4.3-7.9), 5.3 (3.5-7.9), 17.5 (10.6-28.9), 16.7 (10.4-26.7) ng/ml, respectively (logarithmic mean and range of mean +/- S.D. after retransformation). Patients with liver cirrhosis had significantly higher concentrations of NC1 in serum than those with chronic active hepatitis, but there was no difference in serum PIIIP concentrations between the two groups. These data suggest an alteration of type IV collagen metabolism in chronic liver disease. In liver cirrhosis, the metabolism of collagen IV is apparently different from that of collagen type III; serum NC1 determinations may therefore provide additional information on chronic liver disease, particularly in patients with cirrhosis with a normal level of serum PIIIP. Further follow-up studies as well as investigations related to the basic mechanism of the elevation of these peptides in serum are needed in order to understand their clinical significance fully.     

充血性心力衰竭患者血清Ⅰ型前胶原羧基端肽及Ⅲ型前胶原氨基端肽的变化

目的 :研究充血性心力衰竭 (CHF)患者血清Ⅰ型前胶原羧基端肽 (PIP)和Ⅲ型前胶原氨基端肽 (PⅢP)含量变化及与反映左室结构和功能的参数间的关系。方法 :应用放射免疫法测定 2 0例正常人 (对照组 )和 6 1例CHF患者 (CHF组 )血清中PIP和PⅢP浓度 ,用M型超声心动图测算左室重量指数 (LVMI)和左室射血分数(LVEF) ,多普勒超声心动图测定二尖瓣口舒张早期和晚期最大血流速度 (VE和VA)。结果 :CHF组血清中PIP和PⅢP含量较对照组明显升高 ,并随着心功能等级的增加而有升高趋势 ,但与导致心力衰竭的基础病因无关。血清PⅢP和PIP水平与LVMI呈正相关 ,与VE/VA 呈负相关 ,并与同期测定的血浆血管紧张素Ⅱ和醛固酮含量有一定相关性。结论 :CHF患者血清PIP和PⅢP水平显著升高可以反映其左室重构过程中细胞外基质的代谢变化     

Serum carboxy terminal propeptide of type I procollagen to amino terminal propeptide of type III procollagen ratio is a better indicator than each single propeptide and 7S domain type IV collagen for progressive fibrogenesis in chronic viral liver diseases

Twenty chronic viral hepatitis patients, mainly with hepatitis B related with progression to liver cirrhosis were included for an assay of serum collagen markers: PICP (carboxy terminal propeptide of type I procollagen), PIIINP (amino terminal propeptide of type III procollagen), and 7S-IV (7S-domain type IV collagen). PICP is increased in 20% of chronic hepatitis patients with a mean of 190.3 ng/ml, which is not different from that of the follow-up concentration in liver cirrhosis, where 35% of cases were abnormal with a mean of 220.5 ng/ml. The serum level and percent of abnormality of PIIICP in chronic hepatitis and in liver cirrhosis are 23.5 ng/ml vs 14.8 ng/ml and 90% vs 100%, respectively (P>0.05). PICP/PIIINP is significantly higher during liver cirrhosis (15.11 vs 10.08,P<0.05). PICP during chronic hepatitis is not related to serum biochemical changes, while PICP during liver cirrhosis and PIIINP are correlated with hepatic enzymes. 7S-IV in chronic hepatitis and in liver cirrhosis is 14.0 ng/ml vs 10.9 ng/ml, respectively; both were positively correlated with hepatic enzymes. These results suggest that PICP/PIIINP is a better indicator of hepatic fibrogenesis than either PICP or PIIINP alone in viral hepatitis. A ratio of more than 12 is suggestive of liver cirrhosis.     

The serum concentrations of the aminoterminal propeptide of procollagen type III and the hepatic content of mRNA for the α1 chain of procollagen type III in carbon tetrachloride-induced rat liver fibrogenesis

Serum concentrations of the aminoterminal propeptide of procollagen type III (PIIIP) are elevated in fibrogenic diseases of the liver, but the mechanism of elevation is not fully understood. To investigate the mechanism, we compared serum concentrations of PIIIP with total liver content of mRNA for the pro α1 (III) chain, in rats with carbon tetrachloride (CCl₄)-induced liver fibrosis. Adult male rats received CCl₄ in mineral oil twice weekly for 8 weeks and were compared with age-matched controls. Serum concentrations of PIIIP were measured by a specific radioimmunoassay; molecular sizes of PIIIP in serum were also determined. Pro α1 (III) mRNA content in the liver was quantitated by RNA slot-blot hybridization and chemical measurement of total hepatic RNA content. Total collagen content of the liver was estimated by hydroxyproline measurement. All CCl₄-treated animals had septal fibrosis after 4 weeks, and evidence of cirrhosis (regenerative nodules, ascites) was seen after 7 weeks of treatment. Serum concentrations of PIIIP and pro α1 (III) mRNA content in the liver were correlated well until cirrhosis has established. They increased simultaneously after 3 weeks of treatment, 1 week before any elevation of hepatic hydroxyproline could be detected. After cirrhosis has established, pro αl (III) mRNA content in the liver decreased markedly, but serum PIIIP levels continued to be elevated. Hepatic hydroxyproline plateaued after 5 weeks. The molecular sizes of serum PIIIP indicate the release of intact native procollagen peptide during the development of cirrhosis. In conclusion, at least in CCl₄-induced liver fibrosis in the rats, serum PIIIP levels can be used as a fibrogenic marker for the period progressing to cirrhosis. But the use of the serum PIIIP levels in cirrhosis seems to be limited by factors other than liver fibrogenesis.     

Serum procollagen III peptide in alcoholic and other chronic liver diseases

Increased levels of serum procollagen III peptide (P-III-P) have been found in patients with alcoholic hepatitis and cirrhosis. Serum P-III-P was increased (greater than 15 micrograms/l) in 38 of 44 (86%) patients with alcoholic liver cirrhosis, in 6 of 20 (30%) with fatty liver, in 1 of 13 (8%) with non-alcoholic fatty liver, and in 3 of 14 (21%) with other chronic liver diseases. Median serum P-III-P was almost three times higher in alcoholic liver cirrhosis than in alcoholic fatty liver (p less than 0.001). Serum P-III-P was increased in three of six patients with alcoholic fatty liver and periportal fibrosis. In the total material (n = 91), a statistically significant negative correlation between serum P-III-P and albumin (r = -0.71, p less than 0.001) and Normotest (r = -0.63, p less than 0.001), respectively, and a positive correlation between serum P-III-P and bilirubin (r = 0.65, p less than 0.001) were found. The serum level of P-III-P had no prognostic value concerning the mortality in patients with alcoholic cirrhosis.     

Bone marrow fibrosis and disease activity in multiple myeloma monitored by the aminoterminal propeptide of procollagen III in serum

Simple bone marrow fibrosis is seen in 10–30% of multiple myeloma (MM) patients. We investigated the incidence and characteristics of the bone marrow stromal alterations, in order to characterize the collagens involved by immunohistochemistry, and to evaluate the use of serum aminoterminal propeptide of type III procollagen (PIIINP) as a marker of marrow fibrogenesis and disease activity in MM. 34 consecutive patients with newly diagnosed MM were included prospectively, and followed for 12–30 months. Compared with the findings in 15 normal individuals we found increased interstitial deposits of collagen III in 48% of MM patients, whereas deposits of collagen I were not increased. Interstitial fibrosis appeared to be restricted to areas of severe plasma cell infiltration, but it could also have a more dispersed presentation in the severely infiltrated marrow. There was a high co-distribution of collagen III fibrils and reticulin fibres. Serum PIIINP levels were elevated in most patients, and in the follow-up study serum PIIINP showed a good correlation with the response to treatment. Patients with resistant or progressive disease had continually elevated levels of PIIINP. In most patients with responsive disease serum PIIINP normalized, and we observed no relapses in patients who had normal serum PIIINP levels. Other patients who responded to treatment by reduced M-component level, but had persistently elevated serum levels of PIIINP, had either early relapses or developed progression of osteolytic lesions in spite of unchanged M-component levels. Therefore an elevated serum PIIINP during treatment might indicate an active malignant clone. Serum PIIINP does not simply follow the M-component, but gives further information of potential therapeutic value.