Cell Death and Prognosis of Mortality in Alcoholic Hepatitis Patients Using Plasma Keratin-18

Abstract

Alcoholic liver disease encompasses the progressive stages of liver dysfunction that culminates in alcoholic cirrhosis (AC) and in severe cases alcoholic hepatitis (AH). Currently, prognostic scores have limited specificity and sensitivity. Plasma keratin-18 (K18) levels are elevated during liver disease and may be biomarkers of outcome. The objective of this study was to determine if total K18 (M65) or caspase-cleaved K18 (M30) levels were different between AC and AH patients. M65 and M30 levels were measured in plasma of consented healthy controls, and patients with AC and AH. Cell death was assessed by TUNEL staining and caspase activity. M65 and M30 values were significantly higher in AC patients compared to healthy controls and further increased in AH patients. The M65 values and the M30/M65 ratios of non-surviving AH patients were significantly elevated above their surviving counterparts and healthy controls. Statistical analysis indicated that M30/M65 ratios outperformed current indices for accurately distinguishing the prognosis of AH patient. These scores occurred with minimal increase in plasma cell death markers such as ALT and AST. Serum caspase activity, TUNEL staining, and M30 immunohistochemistry in biopsies indicated serum and tissue values may not correlate well with overall cell death. In conclusion, both M65 and M30 differentiate AH from AC patients and M65 values and the M30/M65 ratio are capable of predicting early-stage mortality; however, they may not accurately reflect pure hepatocyte cell death in these populations as they do not strongly correlate with traditional cell death markers.

Is Keratin-18 only a marker of cell death in acute-on-chronic liver failure?

“…Moreover, there was a reduction in the cK18-to-K18 ratio indicating that the presence of necrotic cell death is associated with non-survival (3). These observations largely mirror previous data found in alcoholic hepatitis patients by our own group (5). Further studies are necessary in this area in large, multi-institutional cohorts to validate the potential for cK18-to-K18 ratio or the individual values alone to predict mortality (7).…”

“…Further studies are necessary in this area in large, multi-institutional cohorts to validate the potential for cK18-to-K18 ratio or the individual values alone to predict mortality (7). Multiple studies have now confirmed increases in K18 and cK18 in AH patients (5,6). The current study largely confirms these data but notes that due to near ubiquitous increases in K18 and cK18 in clinically relevant liver diseases, these parameters alone may not be sufficient for establishing ACLF/alcoholic hepatitis (3).…”

“…K18 and cK18 have also been proposed as potential prognostic and diagnostic markers in alcoholic hepatitis (5,6). Their use as biomarkers has been of special interest to the Hepatology community as there are currently no available serum biomarkers that can accurately diagnose alcoholic hepatitis, and thus transjugular liver biopsy remains the gold standard for diagnosis.…”

“…Their use as biomarkers has been of special interest to the Hepatology community as there are currently no available serum biomarkers that can accurately diagnose alcoholic hepatitis, and thus transjugular liver biopsy remains the gold standard for diagnosis. Their inception and use as a diagnostic biomarker could potentially save a number of procedures and assist in diagnosis in tertiary units without the capacity to perform transjugular liver biopsy regularly (3,5,6). K18 and cK18 scores were elevated in non-surviving patients in this study.…”

Mitochondrial dysfunction as a mechanism of drug-induced hepatotoxicity: current understanding and future perspectives

“…Other biomarkers such as miR-122 [244–247], full-length cytokeratin-18 [247–250], high mobility group box 1 (HMGB1) protein [247–249, 251], and argininosuccinate synthetase (ASS) [252] are generally considered indicators of mainly necrotic cell death [253]. On the other hand, increased plasma levels of the caspase-cleaved form of cytokeratin-18 [247, 248, 250, 254, 255] and activated caspases detected as enzyme activity and/or the protein by western blotting [164, 247, 249, 254], are markers of apoptotic cell death. However, due to the sensitivity of the assay, cleaved cytokeratin-18 levels should always be compared to the full-length version in order to assess the relative importance of apoptosis [247, 248, 254].…”