Increased donor liver perfusate levels of an underglycosylated glycoprotein predicted primary transplant nonfunction with 100% accuracy in two prospective cohorts, researchers reported in Gastroenterology.
Glycomic alterations of immunoglobulin G “represent inflammatory disturbances in the liver that [mean it] will fail after transplantation,” wrote Xavier Verhelst, MD, of Ghent (Belgium) University Hospital, and his associates. The new glycomarker “could be a tool to safely select high-risk organs for liver transplantation that otherwise would be discarded from the donor pool based on a conventional clinical assessment,” and also could help prevent engraftment failures. “To our knowledge, not a single biomarker has demonstrated the same accuracy today,” they wrote in the April issue of Gastroenterology .
Chronic shortages of donor livers contribute to morbidity and death worldwide. However, relaxing donor criteria is controversial because of the increased risk of primary nonfunction, which affects some 2%-10% of liver transplantation patients, and early allograft dysfunction, which is even more common. Although no reliable scoring systems or biomarkers have been able to predict these outcomes prior to transplantation, clinical glycomics of serum has proven useful for diagnosing hepatic fibrosis, cirrhosis, and hepatocellular carcinoma, and for distinguishing hepatic steatosis from nonalcoholic steatohepatitis. “Perfusate biomarkers are an attractive alternative [to] liver biopsy or serum markers, because perfusate is believed to represent the condition of the entire liver parenchyma and is easy to collect in large volumes,” the researchers wrote.
Accordingly, they studied 66 patients who underwent liver transplantation at a single center in Belgium and a separate validation cohort of 56 transplantation recipients from two centers. The most common reason for liver transplantation was decompensated cirrhosis secondary to alcoholism, followed by chronic hepatitis C or B virus infection, acute liver failure, and polycystic liverdisease. Donor grafts were transported using cold static storage (21° C), and hepatic veins were flushed to collect perfusate before transplantation. Protein-linked N-glycans was isolated from these perfusate samples and analyzed with a multicapillary electrophoresis-based ABI3130 sequencer.
The four patients in the primary study cohort who developed primary nonfunction resembled the others in terms of all clinical and demographic parameters except that they had a markedly increased concentration (P less than .0001) of a single-glycan, agalacto core-alpha-1,6-fucosylated biantennary glycan, dubbed NGA2F. The single patient in the validation cohort who developed primary nonfunction also had a significantly increased concentration of NGA2F (P = .037). There were no false positives in either cohort, and a 13% cutoff for perfusate NGA2F level identified primary nonfunction with 100% accuracy, the researchers said. In a multivariable model of donor risk index and perfusate markers, only NGA2F was prognostic for developing primary nonfunction (P less than .0001).
The researchers found no specific glycomic signature for early allograft dysfunction, perhaps because it is more complex and multifactorial, they wrote. Although electrophoresis testing took 48 hours, work is underway to shorten this to a “clinically acceptable time frame,” they added. They recommended multicenter studies to validate their findings.
Funders included the Research Fund – Flanders and Ghent University. The researchers reported having no conflicts of interest.
SOURCE: Verhelst X et al. Gastroenterology 2018 Jan 6. doi: 10.1053/j.gastro.2017.12.027 .
