A Liver Disease Study Points to a Protein Target, Not Yet a Treatment

The University of Barcelona highlighted research on October 19 identifying a protein involved in metabolic dysfunction-associated steatotic liver disease, or MASLD. The work connects the transporter ENT1 with changes in liver fat, inflammation and metabolism, using mouse experiments alongside human liver samples. It offers a possible direction for drug research, rather than evidence that a new treatment is ready for patients, according to the university’s announcement.

The study appears in the October 2026 issue of Metabolism, although the paper was available online earlier. That distinction matters: the current development is the university’s public account of the findings, not an October clinical trial or a newly authorized medicine. The journal abstract describes a combination of human biopsies, public gene-expression datasets and diet-induced disease models in mice.

What the transporter does

ENT1 regulates the movement of nucleosides, small molecules used by cells, across the cell membrane. The researchers paid particular attention to adenosine, which the university describes as involved in inflammation and cellular responses to stress. Their question was whether transport of these molecules helps shape the early development of metabolic liver disease, rather than merely changing after the liver has already become damaged.

In experiments comparing mice with and without ENT1, animals lacking the transporter had lower adenosine levels in the liver and were protected against diet-induced fat accumulation, inflammation and fibrosis. They also showed improved glucose tolerance and insulin sensitivity. The paper’s highlights associate protection with reduced body weight and improved metabolic status, an important qualification when interpreting how directly the transporter itself accounts for the liver findings.

Those results suggest an effect extending beyond a single organ. But removing a protein in an experimental animal is not the same intervention as administering a medicine to a person who already has disease. The reported experiments support investigating ENT1; they do not establish an effective dose, a safe treatment schedule or a clinical benefit from an ENT1 inhibitor in people with MASLD.

Why disease stage matters

The human evidence adds another complication. ENT1 expression was higher in early disease but declined as disease progressed, according to the university and the paper’s abstract. Expression describes how active the machinery producing the transporter is; it does not by itself demonstrate that blocking the transporter will reverse disease. A target whose behavior changes over time also raises a practical research question: at which stage, if any, would intervention be useful?

Among people with early MASLD, higher hepatic ENT1 expression was associated with higher insulin levels and a higher HOMA-IR index, an indicator of insulin resistance. This relationship is consistent with a connection between nucleoside transport and broader metabolic disturbances. It remains an association in the human data, however, not proof that ENT1 causes those disturbances or that reducing its activity would correct them.

The university says compounds capable of inhibiting ENT1 already exist, with some in clinical development. That makes the protein a potentially accessible research target, but it does not establish those compounds as treatments for MASLD. The researchers explicitly call for more work, particularly larger human cohorts. The immediate takeaway is a clearer biological hypothesis: nucleoside transport may help connect liver injury with whole-body metabolism, and testing that hypothesis in patients remains ahead.