Cytokeratins in hepatitis

Measurements of serum procollagen-III peptide and M30 do not improve the diagnostic accuracy of transient elastography for the detection of hepatic fibrosis in patients with nonalcoholic fatty liver disease

BACKGROUND

Transient elastography (TE) has recently emerged as an accurate noninvasive imaging method for the diagnosis of liver fibrosis in nonalcoholic fatty liver disease (NAFLD). Here, we tested whether adding serum measures of serum procollagen-III peptide (PIIIP) and caspase-cleaved cytokeratin 18 fragment (M30) to TE could improve its diagnostic accuracy in patients with biopsy-proven NAFLD.

PATIENTS AND METHODS

TE was performed in 87 patients with NAFLD. Serum PIIIP and M30 levels were determined by enzyme-linked immunosorbent assay. Liver histology was considered the gold standard. The diagnostic accuracies were assessed by measuring the area under the receiver operating curve.

RESULTS

At histopathological examination, 34 patients (39.1%) had significant fibrosis (F2-F4) and 19 patients (21.8%) had advanced fibrosis (F3-F4). Both TE and serum M30 levels were independent predictors of fibrosis, whereas no association was found with PIIIP. No significant differences in terms of sensitivity and specificity for both significant and advanced fibrosis were evident for TE, serum M30, or their combination. Moreover, the area under the receiver operating curves of serum M30 combined with TE did not differ significantly from those of either test alone.

CONCLUSION

Both TE and serum M30 levels are accurate for the noninvasive diagnosis of fibrosis in NAFLD. However, their combination did not improve the overall diagnostic accuracy.

Immunofluorescence analysis of cytokeratin 8/18 staining is a sensitive assay for the detection of cell apoptosis

Apoptosis is one of the major types of programmed cell death. During this process, cells experience a series of morphological and biochemical changes. Flow cytometric analysis of Annexin V staining of cell surface phosphatidylserine, in combination with a DNA-staining dye to probe the permeability of the cell membrane, is an established method for detecting apoptosis. The present study aimed to show that the immunofluorescence analysis of cytokeratin (CK) 8/18 staining may provide a new and sensitive assay for the detection of apoptotic cells. Tumor cells were treated with 20 μM cisplatin to induce apoptosis. Following 12 and 24 h of cisplatin treatment, cells were collected and stained with 4′,6-diamidine-2′-phenylindole dihydrochloride (DAPI) and fluorescein-labeled anti-CK8/18 antibody. The apoptotic cells were subsequently examined by fluorescence microscopy. Annexin V-fluorescein isothiocyanate/propidium iodide staining followed by flow cytometric analysis confirmed that cisplatin was able to induce apoptosis in tumor cells. Immunofluorescence analysis demonstrated that apoptotic cells had a distinct CK8/18 staining pattern. In living cells, CK8/18 was uniformly distributed in the cytoplasm and cytosol; however in the apoptotic cells with a condensed and/or fragmented apoptotic nucleus (as identified by DAPI staining), fluorescein-labeled anti-CK8/18 antibody exhibited unusual punctate and/or bubbly staining in the cytosol. In the apoptotic cells that could not be identified by DAPI staining, fluorescein-labeled CK8/18 displayed polarized aggregated staining in the cytosol. These results indicate that fluorescein-conjugated CK8/18 may be a useful and sensitive indicator of cell apoptosis.