Tissue polypeptide specific antigen (TPS) in liver disease

Time-Course Changes of Serum Keratin Concentrations after Liver Transplantation: Contrasting Results of Keratin-18 and Keratin-19 Fragments

Objective

Under normal conditions, adult hepatocytes express only keratin-8 (K8) and keratin-18 (K18), whereas cholangiocytes also express K19. In this study, we delineate the pattern of normal time-course changes in serum K19 and K18 levels after liver transplantation. Patients and Methods. Serum levels of the K19 fragment CYFRA 21-1 and the K18 fragments tissue polypeptide specific antigen (TPS) and M30 (a neoepitope that is generated after caspase cleavage during apoptosis) were measured at baseline and at regular intervals (up to 6 months) after liver transplantation in 11 adult patients.

Results

There was a gradual decrease in serum K19 concentrations from baseline values after transplantation, following a time-course pattern similar to that of serum bilirubin. In contrast, serum concentrations of K18 fragments increased markedly shortly after transplantation and gradually decreased thereafter, following a time-course pattern similar to that of serum transaminases. The increase in TPS tended to occur earlier than that in M30, suggesting an initial predominance of hepatocyte necrosis followed by a predominance of apoptosis in the first days after transplantation. Five patients presented posttransplant complications (acute rejection in three cases and HCV recurrence in two cases). An early increase in serum K19 concentrations was observed in all cases. An increase in serum concentrations of K18 fragments (M30 and TPS) was observed in the two cases with HCV recurrence and was more variable in the three cases with acute rejection.

Conclusions

Serum concentrations of K19 and K18 fragments follow a dissimilar pattern of time-course changes after liver transplantation. The diagnostic value of variations in these normal patterns should be addressed in future studies.

Synergistic effect of alcohol consumption and body mass on serum concentrations of cytokeratin-18

BACKGROUND

Cytokeratin-18 is an essential component of the cytoskeleton of epithelial cells (including hepatocytes). Serum concentrations of cytokeratin-18 (tissue polypeptide-specific antigen [TPS]) are used as a marker of epithelial neoplasms. Here, we investigated the potential interaction between alcohol and obesity in relation to serum TPS concentrations.

METHODS

Alcohol consumption, body mass index, and components of metabolic syndrome were measured in a random sample (n = 420) of the adult population (aged 18 to 92 years, 45% men) from a single municipality. Regular alcohol intake of >20 g/d (women) or >30 g/d (men) was considered risky drinking. Serum TPS was measured with a commercial immunoassay.

RESULTS

Risky drinking was associated with increased serum concentrations of TPS, which was particularly evident among obese individuals. Among individuals without risky drinking, TPS concentrations were similar for all levels of body mass. Conversely, among risky drinkers, serum TPS concentrations increased in parallel with body mass (p = 0.002). The odds ratio of a high (>100 U/l) TPS concentration for the combination of risky drinking and obesity was greater than the additive effect of the 2 separate factors, after adjusting for age and sex. A similar interaction was observed between risky drinking and abdominal adiposity, a major component of the metabolic syndrome. Serum TPS concentrations were correlated with markers of liver damage. Serum TPS was not superior to standard markers (gamma-glutamyl transferase and red blood cell mean volume) for the detection of risky drinking.

CONCLUSIONS

There is a synergism between risky alcohol consumption and common metabolic disorders (particularly obesity) in relation to serum concentrations of cytokeratin-18 (TPS), which probably reflect liver disease.

Quantitation of tissue polypeptide antigen (TPA) in hepatic and systemic circulation in patients with chronic liver diseases

BACKGROUND AND AIM

Abnormal serum tissue polypeptide antigen (TPA) values are commonly found in patients with chronic liver damage and liver cirrhosis even in the absence of malignancies. The aim of this study was to compare serum TPA levels in patients with cirrhosis, to examine correlations between TPA levels and the degree of portal hypertension, and to evaluate TPA concentrations in paired hepatic and peripheral blood samples.

METHODS

A total of 128 patients with chronic liver disease of various severity were studied prospectively. TPA concentrations in hepatic vein and peripheral blood were determined, and Hepatic Vein Pressure Gradient (HVPG) was measured.

RESULTS

TPA levels were significantly higher in patients with cirrhosis than in those with chronic hepatitis, and in systemic circulation than in hepatic vein blood. Peripheral but not hepatic TPA levels did correlate with the HVPG. Subjects with clinically significant portal hypertension (HVPG > 10 mmHg) showed significantly higher peripheral TPA levels than those with HVPG < 10 mmHg.

CONCLUSIONS

Our data suggest that the increased TPA levels observed in cirrhotic patients and the high systemic-to-hepatic blood TPA gradient are probably due to the presence of portal-systemic shunts rather than to hepatic necro-inflammatory activity. In clinical practice, TPA determination could help us to identify and to follow up cirrhotic patients with more severe portal hypertension.

Serum levels of keratin-18 fragments [tissue polypeptide-specific antigen (TPS)] are correlated with hepatocyte apoptosis in alcoholic hepatitis

Apoptosis is a major feature in alcoholic hepatitis. During apoptosis, the M30 neoepitope becomes exposed after keratin-18 cleavage. The tissue polypeptide-specific antigen (TPS) is a keratin-18 fragment that is routinely used as a tumor marker. Serum TPS levels are increased in patients with alcoholic hepatitis. The aim of this study was to investigate the possible relationship of TPS levels with hepatocyte apoptosis in alcoholic hepatitis. Thirty-one patients with alcoholic hepatitis and 22 with fatty liver were included. Hepatocyte apoptosis was evaluated by M30 immunostaining. Serum TPS levels were measured by a commercial immunoassay. The apoptotic score was higher in patients with alcoholic hepatitis than in patients with fatty liver. There was a significant correlation between the apoptotic score and TPS levels. The correlation of the apoptotic score with TPS levels was stronger than with standard liver tests. Serum TPS may be a marker of apoptosis in alcoholic hepatitis.

Serum concentrations of the tissue polypeptide specific antigen in patients suffering from non-alcoholic steatohepatitis

BACKGROUND

Liver histology is the gold standard for diagnosis of non-alcoholic fatty liver disease. Ethical considerations and patient choice often preclude performing a liver biopsy, especially considering the rare but potential risk. Searching for a good serological marker substitute for the invasive procedure was the aim of our study. Keratins, mainly 8 and 18, play not only a mere structural role providing mechanical stability to hepatocytes, but also represent a target via toxic stress ultimately inducing apoptosis/necrosis. Tissue polypeptide-specific antigen (TPS), a serological mirror of keratin 18, is widely used as a marker for various cancers. This antigen was assessed in three different groups who were overweight or obese.

MATERIALS AND METHODS

In this cross-sectional case-control study, 48 cancer-free patients with non-alcoholic steatohepatitis (NASH, Group 1), 48 patients with pure fatty liver (FL, Group 2), and 47 volunteers (Group 3) were studied. All of them were referred to our metabolic unit for routine evaluation.

RESULTS

The median (range) TPS levels were 123 (56-286) ng mL(-1) in NASH patients. FL patients and volunteers had significantly lower TPS levels, 76 (38-98) ng mL(-1) and 64 (28-87) ng mL(-1), respectively (P = 0.0001). A value of 88 ng mL(-1) in patients with underlying bright liver was associated with a high probability of NASH (sensitivity and specificity = 92% and 96%, respectively). One patient (2.1%) with FL had a TPS value > 88 ng mL(-1), but in the same group, 29 FL patients (60.4%) had an alanine aminotransferase value > 40 U L(-1). Based on a recent classification of liver fibrosis, the median (range) TPS values were significantly different among the stages: F1 (n = 23) = 100 (76-264) ng mL(-1); F2 (n = 21) = 134 (56-276) ng mL(-1); and F3 (n = 4) = 199.5 (123-286) ng mL(-1), respectively (P = 0.014).

CONCLUSIONS

Our study shows that TPS is a better marker than alanine aminotransferase activity, ultrasonography or the combination of both parameters in differentiating NASH from FL.

Serum levels of cytokeratin-18 (tissue polypeptide-specific antigen) in liver diseases

OBJECTIVE

The tissue polypeptide-specific antigen (TPS, cytokeratin-18, a normal constituent of the hepatocyte cytoskeleton) is a standard tumour marker. This study aimed to evaluate serum TPS levels in patients with liver disease.

METHODS

Serum TPS was measured with a commercial immunoassay in 884 individuals (753 outpatients from a liver disease clinic, 131 patients admitted to the hospital with acute liver disease).

RESULTS

Abnormally high (> 80 U/l) TPS levels were found in 57.7% (95% CI 54.0-61.3%) of outpatients with liver disease. Elevated TPS levels were observed for all liver diseases, including fatty liver, alcoholic disease, chronic viral hepatitis, autoimmune hepatitis, cholestasis, transplantation, and hepatocarcinoma. TPS levels correlated with liver markers, particularly serum AST. In addition, TPS levels correlated with Knodell's score in patients with chronic hepatitis. TPS was increased in one-third of patients with normal liver enzyme values. Serum TPS levels decreased after specific therapy in patients with hepatitis C and autoimmune hepatitis. Abnormally high TPS levels were found in the vast majority of patients admitted to the hospital, with markedly high (> 800 U/l) values being observed in 47.5% (95% CI 36.1-55.7%) of patients with alcoholic liver disease and in 80.8% (95% CI 60.0-92.7%) of patients with acute hepatitis.

CONCLUSIONS

Serum TPS (cytokeratin-18) is elevated in patients with non-malignant liver diseases, particularly in those with prominent cytolysis. Further studies are needed to evaluate the use of TPS as a marker of liver disease.

Serum cytokeratins in alcoholic liver disease: contrasting levels of cytokeratin-18 and cytokeratin-19

Serum cytokeratin (CK) levels are widely used as tumor markers. Serum levels of CK-18, a tumor marker also known as tissue polypeptide specific antigen (TPS), are increased in patients with alcoholic liver disease. Cytokeratin-18 is the main component of Mallory bodies, a hallmark of alcoholic hepatitis, which may also contain CK-19. Serum levels of CK-18 and CK-19, a tumor marker also known as CYtokeratin FRAgment 21-1 (CYFRA 21-1) were investigated in (a) heavy drinkers with alcoholic liver disease (n=15), (b) patients with malignancy (n=22), and (c) healthy controls (n=10). Serum levels of CYFRA 21-1 (CK-19) were markedly increased in patients with malignancy, but were similar in heavy drinkers and healthy controls. In contrast, serum levels of TPS (CK-18) in heavy drinkers were higher than those of healthy controls, and even tended to be higher than those of patients with malignancy. Both CK-19 and CK-18 levels were higher in cases of alcoholic hepatitis than in cases of fatty liver. Correlation with hepatocyte CK inclusions was stronger for serum TPS (CK-18) than for CYFRA 21-1 (CK-19). In conclusion, serum CYFRA 21-1 (CK-19) and TPS (CK-18) show a different pattern of increase that could reflect the composition of the altered hepatocyte CK network in alcoholic liver disease. Their usefulness as tumor markers, particularly that of serum TPS (CK-18), may be limited in patients with alcoholic liver disease.

Serum levels of tissue polypeptide specific antigen are correlated with hepatocyte cytokeratin expression in alcoholic liver disease

BACKGROUND

Serum levels of the tumor marker tissue polypeptide specific antigen (TPS, cytokeratin 18 fragments) are increased in patients with alcoholic liver disease, particularly in cases of alcoholic hepatitis. Mallory bodies, characteristic of alcoholic hepatitis, are cytokeratin 8 and 18 aggregates. The study was aimed at investigating the possible relationship of serum TPS levels with hepatocyte cytokeratin expression in patients with alcoholic liver disease.

METHODS

Twenty-four patients with alcoholic liver disease were studied. Immunohistochemical staining for cytokeratins 8 and 18 was performed in liver specimens by means of CAM 5.2 monoclonal antibody. The number of hepatocytes containing CAM 5.2-reactive cytokeratin inclusions was compared with serum TPS levels.

MAIN RESULTS AND CONCLUSIONS

The vast majority of alcoholics (95%) showed increased (>100 units/liter) serum TPS levels. Serum TPS levels were significantly correlated with the number of hepatocyte cytokeratin inclusions. Serum TPS levels can predict hepatocyte cytokeratin expression in patients with alcoholic liver disease.

The cytoskeleton of digestive epithelia in health and disease

The mammalian cell cytoskeleton consists of a diverse group of fibrillar elements that play a pivotal role in mediating a number of digestive and nondigestive cell functions, including secretion, absorption, motility, mechanical integrity, and mitosis. The cytoskeleton of higher-eukaryotic cells consists of three highly abundant major protein families: microfilaments (MF), microtubules (MT), and intermediate filaments (IF), as well as a growing number of associated proteins. Within digestive epithelia, the prototype members of these three protein families are actins, tubulins, and keratins, respectively. This review highlights the important structural, regulatory, functional, and unique features of the three major cytoskeletal protein groups in digestive epithelia. The emerging exciting biological aspects of these protein groups are their involvement in cell signaling via direct or indirect interaction with a growing list of associated proteins (MF, MT, IF), the identification of several disease-causing mutations (IF, MF), the functional role that they play in protection from environmental stresses (IF), and their functional integration via several linker proteins that bridge two or potentially all three of these groups together. The use of agents that target specific cytoskeletal elements as therapeutic modalities for digestive diseases offers potential unique areas of intervention that remain to be fully explored.

M3/M21 serum levels in women with adnexal masses and inflammatory diseases

The aim of the present study was to evaluate the clinical usefulness of the cytokeratin tumor marker M3/M21 as a screening marker for ovarian cancer, as a predictive marker in patients with adnexal masses and as a prognostic factor in women with ovarian cancer. To determine the specificity of the M3/M21 test, we investigated M3/M21 serum levels in several benign conditions. This retrospective study comprises 37 patients with ovarian cancer FIGO stages Ia to III. Sera of patients with benign cysts, endometriosis, pelvic inflammatory disease, inflammatory bowel disease and liver cirrhosis were evaluated in 90, 10, 38, 10 and 20 cases, respectively. With a sensitivity of 57% and a specificity of 95%, M3/M21 is not suitable as a screening marker for ovarian cancer. Although M3/M21 is able to discriminate between ovarian cancer and benign adnexal tumors (univariate logistic regression, p = 0.0003), M3/M21 does not provide information additional to CA 125. M3/M21 serum levels are elevated in several benign conditions such as liver cirrhosis and inflammatory bowel disease. In ovarian cancer patients, elevated M3/M21 serum levels prior to therapy were associated with poor overall and disease-free survival (log-rank test, p = 0.03; log-rank test, p = 0.01, respectively). M3/M21, while obviously not suitable for screening or differential diagnosis of adnexal masses, could be useful as an additional prognostic factor in ovarian cancer patients.