Analysis of factors contributing to higher erythropoietin levels in patients with chronic liver disease

Pharmacokinetics of Daprodustat and Metabolites in Individuals with Normal and Impaired Hepatic Function

Daprodustat is a hypoxia‐inducible factor‐prolyl hydroxylase inhibitor in development for treatment of anemia of chronic kidney disease. We evaluated the role of hepatic impairment on daprodustat pharmacokinetics, pharmacodynamics, and tolerability. Participants with mild (Child‐Pugh Class A, score 5‒6) and moderate (Child‐Pugh Class B, score 7‒9) hepatic impairment and matched healthy controls were administered single 6‐mg doses of daprodustat. Exposure parameters were determined for daprodustat and its six metabolites. Comparisons resulted in 1.5‐ and 2.0‐fold higher daprodustat C_max and area under the curve (AUC) exposures in participants with mild and moderate hepatic impairment, respectively, versus controls; C_max in mild hepatic impairment was comparable to controls. Similarly, aligned with parent drug, unbound daprodustat C_max and AUC exposures increased 1.6‐ to 2.3‐fold in hepatic‐impaired participants versus controls, and metabolite exposures were 1.2‐ to 2.0‐fold higher in participants with hepatic impairment. Erythropoeitin (EPO) baseline‐corrected AUC exposures were between 0.3‐fold lower and 2.2‐fold higher in matched controls versus hepatic‐impaired participants. No serious or study drug‐related adverse events were reported. Daprodustat exposure was increased in participants with moderate and mild hepatic impairment compared with matched controls; however, no meaningful differences in EPO were observed and no new safety concerns were identified (ClinicalTrials.gov: NCT03223337).

EV-3, an endogenous human erythropoietin isoform with distinct functional relevance

Generation of multiple mRNAs by alternative splicing is well known in the group of cytokines and has recently been reported for the human erythropoietin (EPO) gene. Here, we focus on the alternatively spliced EPO transcript characterized by deletion of exon 3 (hEPOΔ3). We show co-regulation of EPO and hEPOΔ3 in human diseased tissue. The expression of hEPOΔ3 in various human samples was low under normal conditions, and distinctly increased in pathological states. Concomitant up-regulation of hEPOΔ3 and EPO in response to hypoxic conditions was also observed in HepG2 cell cultures. Using LC-ESI-MS/MS, we provide first evidence for the existence of hEPOΔ3 derived protein EV-3 in human serum from healthy donors. Contrary to EPO, recombinant EV-3 did not promote early erythroid progenitors in cultures of human CD34+ haematopoietic stem cells. Repeated intraperitoneal administration of EV-3 in mice did not affect the haematocrit. Similar to EPO, EV-3 acted anti-apoptotic in rat hippocampal neurons exposed to oxygen-glucose deprivation. Employing the touch-screen paradigm of long-term visual discrimination learning, we obtained first in vivo evidence of beneficial effects of EV-3 on cognition. This is the first report on the presence of a naturally occurring EPO protein isoform in human serum sharing non-erythropoietic functions with EPO.

Darbepoetin-α inhibits the perpetuation of necro-inflammation and delays the progression of cholestatic fibrosis in mice

Biliary obstruction and cholestasis result in hepatocellular necro-inflammation and lead to the development of liver fibrosis. The objective of this study was to analyze whether the multiple tissue-protective properties of erythropoietin are salutary in an experimental model of liver fibrosis. For this purpose, C57BL/6J mice underwent common bile duct ligation (BDL) and were treated with either darbepoetin-α (10 μg/kg i.p.) or physiological saline every third day, beginning 24 h after BDL. Mice were killed at 2, 5, 14, and 28 days after BDL. Beside hematological parameters, markers of inflammation and fibrosis were assessed histomorphometrically and immunohistochemically as well as by quantitative real-time PCR. In addition, a 7-week survival study was performed. BDL provoked cholestatic hepatitis characterized by biliary infarcts with accumulation of macrophages followed by marked collagen deposition and increased expression of profibrotic gene transcripts. Darbepoetin-α treatment significantly diminished the area of focal necrosis, reduced the infiltration of macrophages, decreased levels of profibrotic genes, and lowered collagen deposition. Moreover, darbepoetin-α significantly reduced systemic anemia caused by BDL. Finally, darbepoetin-α treatment significantly prolonged the survival time after BDL. This study suggests that darbepoetin-α, which is a clinically well-established substance, might be used as an efficient therapeutic option for patients with chronic cholestatic liver disease.

Hepatic changes of erythropoietin gene expression in a rat model of acute-phase response

An acute-phase response is the systemic reaction of an organism to insult (e.g. infection, trauma and burning). It represents the 'first line' of defence of the body to tissue-damaging attacks. In the present work, we used a rat model of an intra-muscular turpentine oil (TO) injection to analyse erythropoietin (EPO) gene expression changes in the liver, one of the main target organs of acute-phase cytokines. EPO began to increase in the serum of TO-treated animals 6 h after injection and reached a maximum at 24 h (125+/-20 pg/ml). The detection of total RNA by polymerase chain reaction analysis showed that the levels of EPO gene expression in the liver were considerably increased between 2 and 12 h by up to 20-fold at the peak after TO administration, followed by a gradual decrease over the next 48 h, although the values remained significantly higher compared with the control group. In the kidney, after a sudden slight increase, the values declined progressively to 3.5-fold decrease at 12 h after the injection. In the liver, a parallel upregulation of the hypoxia-inducible factor-1 (HIF-1) alpha gene was observed (up to 4.7-fold increase), while HIF-2 alpha gene expression remained unaltered. On the other hand, the protein of both genes became detectable after the injection and increased progressively over 24 h, with a subsequent decline. These results suggest that EPO may be added to the increasing group of positive acute-phase proteins and the liver might represent the major source of the hormone under these conditions in the rat.

[Diagnosis of anemia in alcoholic cirrhosis]

PURPOSE

Anemia in patients with alcoholic liver cirrhosis is a common issue. The diagnosis could be difficult because of the multiplicity of causes, usually associated, and specificities in the diagnostic approach. This subject has not been reviewed for almost two decades. We propose a review based upon analysis of the literature and our clinical experience.

CURRENT KNOWLEDGE AND KEY POINTS

Because of the alcoholism and the biological consequences of the liver disease, laboratory findings, especially the mean corpuscular volume, should be interpreted with caution in the diagnostic approach. Despite these drawbacks, the diagnosis of anemia is detailed according to the usual plan: normocytic, macrocytic and microcytic anemias. Finally, we propose practical guidelines.

FUTURE PROSPECTS AND PROJECTS

Further prospective studies should assess the real burden of nutritional deficiencies, easily treatable. The prognostic significance of hemolytic anemias in patients with alcoholic liver cirrhosis should be studied.

Clinical and prognostic role of plasma coagulation factor XIII activity for bleeding disorders and 6-year survival in patients with chronic liver disease

BACKGROUND/AIMS

Alterations of plasma coagulation factor XIII may contribute to bleeding disorders in patients with liver cirrhosis. As standard clotting tests such as prothrombin time or activated thromboplastin time (aPTT) cannot detect factor XIII deficiency, this may often be overlooked in clinical practice. We aimed to define factor XIII's clinical and prognostic role in chronic liver disease.

PATIENTS AND METHODS

Factor XIII activities were assessed among various other parameters in 111 patients with chronic liver diseases during evaluation for liver transplantation in a prospective study.

RESULTS

Unlike coagulation factors II, V or VII, factor XIII activity was maintained in the majority of patients with liver cirrhosis. However, although rarely, factor XIII deficiencies (<50%) occurred, especially in Child C cirrhosis. Factor XIII levels correlated with liver's biosynthetic capacity (cholinesterase activity, albumin, total protein) as well as with platelet count, global coagulation tests and other single coagulation factors. Patients reporting a current systemic bleeding tendency at study entry had significantly reduced factor XIII. In a 6-year follow-up, patients with factor XIII<50% had a significantly increased risk of severe upper gastrointestinal bleed, and reduced factor XIII (<50%, 50-75% vs. normal) was associated with increased mortality.

CONCLUSIONS

Factor XIII deficiency is rare in patients with liver cirrhosis, but is associated with a clinical bleeding tendency and an unfavorable prognosis for future hemorrhages and survival.

High adiponectin in chronic liver disease and cholestasis suggests biliary route of adiponectin excretion in vivo

BACKGROUND/AIMS

Models of fatty liver diseases and fibrosis suggest a hepatoprotective effect of adiponectin, an adipocyte-derived hormone with antidiabetic, antiobesity, antiatherogenic and anti-inflammatory effects.

METHODS

We studied adiponectin serum levels in 111 chronic liver disease (CLD) patients and 226 healthy controls and the impact of cholestasis on adiponectin by bile duct ligation experiments in mice.

RESULTS

Adiponectin was significantly elevated in CLD, and correlated with stage of liver cirrhosis, liver cell injury, e.g. aminotransferase activity, and inflammatory markers, but not with liver synthesis capacity, insulin sensitivity (HOMA index) or clinical complications. As patients with biliary liver diseases and cholestasis exhibited the highest adiponectin levels, we experimentally investigated a potential biliary route of adiponectin excretion. Following bile duct ligation in mice adiponectin levels rapidly increased without affecting hepatic adiponectin gene expression. Also, adiponectin was detectable in human bile. High adiponectin concentrations were associated with severe cholangitis and/or cholestasis on liver histology.

CONCLUSIONS

Adiponectin is elevated in chronic liver disease and correlates with inflammation and liver damage. High adiponectin levels after bile duct ligation in mice and in human bile from cholestatic patients suggest that biliary secretion is involved in adiponectin clearance and that adiponectin could serve as a novel marker indicating cholestasis in liver cirrhosis.