Assessment of liver fibrosis: Can serum become the sample of choice?

Serum N-terminal DDR1: A Novel Diagnostic Marker of Liver Fibrosis Severity

BACKGROUND AND AIMS

The expression of discoidin domain receptor 1 (DDR1) is commonly up-regulated and undergoes collagen-induced ectodomain (N-terminal) shedding during the progression of liver fibrosis. This study aimed to evaluate the clinical utility of N-terminal DDR1 as a diagnostic biomarker for liver fibrosis.

METHODS

N-terminal DDR1 shedding was evaluated using cell lines, liver fibrosis mouse models, clinical data of 298 patients collected from February 2019 to June 2020. The clinical data were divided into test and validation cohorts to evaluate the diagnostic performance of serum N-terminal DDR1.

RESULTS

Time- and dosage-dependent N-terminal DDR1 shedding stimulated by collagen I was observed in a hepatocyte cell line model. The type I collagen deposition and serum N-terminal DDR1 levels concurrently increased in the development of liver fibrosis in mouse models. Clinical data demonstrated a significant diagnostic power of serum N-terminal DDR1 levels as an accurate biomarker of liver fibrosis and cirrhosis. The diagnostic performance was further increased when applying N-DDR1/albumin ratio, achieving area under the curve of 0.790, 0.802, 0.879, and 0.865 for detecting histological fibrosis stages F ≥2, F ≥3, F 4 with liver biopsy as a reference method, and cirrhosis according to imaging techniques, respectively. With a cut-off of 55.6, a sensitivity, specificity, positive predictive value, and negative predictive value of 82.7%,76.6%, 67.4%, and 88.3% were achieved for the detection of cirrhosis.

CONCLUSIONS

Serum N-terminal DDR1 appears to be a novel diagnostic marker for liver fibrosis.

Gelatinase activities and TIMP-2 serum level in alcohol cirrhosis and chronic pancreatitis

There are some divergent data concerning the role of matrix metalloproteinase (MMP)-2, MMP-9 and tissue inhibitor of MMP (TIMP)-2 in the pathogenesis of alcoholic cirrhosis (AC) and chronic pancreatitis (CP). Our objective was to evaluate the activity of MMP-2, MMP-9 and TIMP-2 serum levels in patients with AC and CP. Twenty-one patients with diagnosis of AC and twenty-two with CP admitted to the outpatient clinic for a control visit were enrolled. All results were compared with age and sex-matched control group (n=19). The sera obtained from venous blood were stored at -70°C for further analysis. Activity of MMP-2 and MMP-9 were evaluated with gelatin zymography, TIMP-2 serum level was analyzed with the usage of ELISA method. A significant decrease of serum MMP-2 activity was noted in sera of AC and CP patients in comparison with control. Activity of MMP-9 was elevated only in CP patients and TIMP-2 serum level was elevated only in AC patients. Decreased activity of MMP-2 in AC patients can contribute to cirrhosis development. The high level of MMP-9 in serum related to CP patients theoretically can exacerbate the inflammatory process within the pancreas.

The decrease of serum MMP-2 activity corresponds to alcoholic cirrhosis stage

Because of numerous limitations for liver biopsy, a noninvasive marker of liver cirrhosis is sought. Promising indicators seem to be matrix metalloproteinases (MMPs) that are responsible for degradation of extracellular matrix. The aim of the study was to evaluate the gelatinase activities (MMP-2 and MMP-9) in patients with different stages of alcoholic cirrhosis. Sixty-seven outpatients who presented various stages of alcoholic cirrhosis according to Child-Turcotte-Pugh criteria and 26 healthy control subjects were enrolled. Blood samples were collected for MMP-2 and MMP-9 activities. A significant decrease of serum MMP-2 activity was noted in stages B and C of cirrhosis in comparison with control. Serum MMP-9 activity did not depend on the stage of cirrhosis. The MMP-2 levels, but not those of MMP-9, may be of value in understanding the pathogenesis and progression of alcoholic cirrhosis.

Pattern of AST and ALT changes in Relation to Hemolysis in sickle cell Disease

Background

Elevated aminotransferase levels are commonly associated with compromised hepatic integrity from various insults. In sickle cell disease, aspartate transaminase (AST) is also released via intravascular hemolysis. This study was done to determine the pattern of changes in AST and alanine transaminase (ALT), in particular the AST:ALT ratio, and to relate these to the hemolytic state, which we consider to be more important than hepatic and cardiac dysfunction in some individuals with sickle cell disease.

Methods

Serum aminotransferase levels were measured in 330 subjects with sickle cell disease, as well as hemoglobin, reticulocytes, and lactate dehydrogenase. The AST:ALT ratio was designated as a hemolytic marker, and simple and multivariate regression analyses were carried out between this ratio and other hemolytic markers.

Results

Mean AST and ALT levels were 48.24 % 27.78 and 26.48 % 22.73 U/L, respectively. However, for 49 subjects without sickle cell disease, mean AST and ALT levels were the same, ie, 23.0 U/L. In the subjects with sickle cell disease, the increases in AST levels were far higher than for ALT, supporting its release via intravascular hemolysis. In 95.8% of the subjects with sickle cell disease, the AST:ALT ratio was > 1, but our results did not suggest overt malfunctioning of the liver and heart in the majority of subjects.

Conclusion

Regression analyses support the use of the AST:ALT ratio as a hemolytic marker, because it has an inverse association with the hemoglobin level. Whether in steady state or in crisis, provided hepatic and cardiac integrity has not been compromised, subjects with sickle cell disease would have higher AST levels due to the hemolytic nature of the condition. This is the first report highlighting the AST:ALT ratio in sickle cell disease.

Detection of novel biomarkers of liver cirrhosis by proteomic analysis

Hepatic cirrhosis is a life-threatening disease arising from different chronic liver disorders. One major cause for hepatic cirrhosis is chronic hepatitis C. Chronic hepatitis C is characterized by a highly variable clinical course, with at least 20% developing liver cirrhosis within 40 years. Only liver biopsy allows a reliable evaluation of the course of hepatitis C by grading inflammation and staging fibrosis, and thus serum biomarkers for hepatic fibrosis with high sensitivity and specificity are needed. To identify new candidate biomarkers for hepatic fibrosis, we performed a proteomic approach of microdissected cirrhotic septa and liver parenchyma cells. In cirrhotic septa, we detected an increasing expression of cell structure associated proteins, including actin, prolyl 4-hydroxylase, tropomyosin, calponin, transgelin, and human microfibril-associated protein 4 (MFAP-4). Tropomyosin, calponin, and transgelin reflect a contribution of activated stellate cells/myofibroblasts to chronic liver injury. The expression of tropomyosin, transgelin, and MFAP-4, an extracellular matrix associated protein, were further evaluated by immunohistochemistry. Tropomyosin and MFAP-4 demonstrated high serum levels in patients with hepatic cirrhosis of different causes.

CONCLUSION

A quantitative analysis of MFAP-4 serum levels in a large number of patients showed MFAP-4 as novel candidate biomarker with high diagnostic accuracy for prediction of nondiseased liver versus cirrhosis [area under receiver operating characteristic curve (AUC) = 0.97, P < 0.0001] as well as stage 0 versus stage 4 fibrosis (AUC = 0.84, P < 0.0001), and stages 0 to 3 versus stage 4 fibrosis (AUC = 0.76, P < 0.0001).

Sampling variability of computer-aided fractal-corrected measures of liver fibrosis in needle biopsy specimens

AIM: To assess the sampling variability of computer-aided, fractal-corrected measures of fibrosis in liver biopsies.

METHODS: Samples were derived from six to eight different parts of livers removed from 12 patients with clinically and histologically proven cirrhosis undergoing orthotopic liver transplantation. Sirius red-stained sections with a thickness of 2 μm were digitized using a computer-aided image analysis system that automatically measures the surface of fibrosis, as well as its outline perimeter, fractal surface and outline dimensions, wrinkledness, and Hurst coefficient.

RESULTS: We found a high degree of inter-sample variability in the measurements of the surface [coefficient of variation (CV) = 43% ± 13%] and wrinkledness (CV = 28% ± 9%) of fibrosis, but the inter-sample variability of Hurst’s exponent was low (CV = 14% ± 2%).

CONCLUSION: This study suggests that Hurst’s exponent might be used in clinical practice as the best histological estimate of fibrosis in the whole organ, and evidences the fact that biopsy sections, which are fundamental for the qualitative diagnosis of chronic hepatitis, play a key role in the quantitative estimate of architectural changes in liver tissue.