The effects of heparins on the liver: application of mechanistic serum biomarkers in a randomized study in healthy volunteers

Abstract

Heparins have been reported to cause elevations in serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) but have not been associated with clinically significant liver injury. The mechanisms underlying these benign laboratory abnormalities are unknown. Forty-eight healthy men were randomized to receive subcutaneous injections of unfractionated heparin (UFH; 150 U/kg), enoxaparin sodium (1 mg/kg), dalteparin sodium (120 IU/kg), or adomiparin sodium (125 IU/kg; a novel heparin) every 12 h for 4.5 days. Asymptomatic elevations in serum ALT or AST were observed in >90% of the subjects. Elevations were also observed in the levels of serum sorbitol dehydrogenase (SDH), glutamate dehydrogenase (GLDH), miR-122, high-mobility group box-1 protein (including the acetylated form), full-length keratin 18, and DNA. Keratin 18 fragments, which are apoptosis biomarkers, were not detected. Biomarker profiles did not differ significantly across heparin treatments. We conclude that heparins as a class cause self-limited and mild hepatocyte necrosis with secondary activation of an innate immune response.

Figures

Figure 1

Serum alanine aminotransferase (ALT) levels in each study subject before, during, and after twice-daily subcutaneous injections of (a) unfractionated heparin (150 U/kg), (b) dalteparin sodium (120 IU/kg), (c) enoxaparin sodium (1 mg/kg), and (d) adomiparin sodium (125 IU/kg). The subjects received the first dose on the morning of day 1 and the final dose on the morning of day 5. The upper limit of the normal reference range is denoted by the dotted line. ULN, upper limit of normal.

Figure 2

Serum measurements of liver injury biomarkers (a) sorbitol dehydrogenase (SDH); (b) glutamate dehydrogenase (GLDH); and biomarkers of cellular injury modality, including (c) cleaved keratin 18 (cleaved K18) and (d) full-length keratin 18 (K18); are depicted as mean values ± SEM. The subjects received the first dose on the morning of day 1 and the final dose on the morning of day 5. The upper limit of the normal reference range or the average (Avg.) baseline value is denoted by the dotted line. Unfractionated heparin (filled circles), enoxaparin sodium (open squares), dalteparin sodium (filled triangles), and adomiparin sodium (filled squares). ULN, upper limit of normal.

Figure 3

Serum measurements of (a) the cellular necrosis biomarker, high-mobility group box-1 protein (HMGB1), and (b) hepatocyte injury biomarker miR-122 are depicted as the mean value ± SEM for each treatment. The subjects received the first dose on the morning of day 1 and the final dose on the morning of day 5. The upper limit of the normal reference range or the average (Avg.) baseline value is denoted by the dotted line. Unfractionated heparin (filled circles), enoxaparin sodium (open squares), dalteparin sodium (filled triangles), and adomiparin sodium (filled squares). ULN, upper limit of normal.

Figure 4

Acetylation of high-mobility group box-1 protein (HMGB1) at baseline (day 1) and during the first peak (day 5) and second peak (day 7). The values, expressed as (a) multiples of baseline value, (b) multiples of ULN, and (c) percentage of total HMGB1, are depicted as the mean value ± SEM for each treatment. In this assay, the upper limit of normal was 0.12 ng/ml and the mean values obtained during the second peak were 1–2 ng/ml. UFH, unfractionated heparin; ULN, upper limit of normal.