Scientists have developed a drug that hunts down harmful “zombie cells” in the liver, offering new hope for millions suffering from fatty liver disease that can progress to cancer.
The experimental compound, called 753b, selectively destroys senescent cells—cellular misfits that have stopped dividing but refuse to die, instead pumping out inflammatory toxins that damage surrounding tissue.
Published in Nature Aging, the research demonstrates how this targeted approach could prevent metabolic dysfunction-associated steatotic liver disease (MASLD) from advancing to more serious conditions. MASLD affects 38% of adults worldwide and represents one of the fastest-growing causes of liver-related deaths, particularly among people with obesity and diabetes.
A Precision Strike Against Cellular Troublemakers
Unlike previous senolytic drugs that clear aging cells throughout the body, 753b concentrates specifically in the liver and spleen. This tissue-selective approach emerged from an unexpected discovery during pharmacokinetic studies—the compound naturally accumulates in these organs, creating higher concentrations that persist for extended periods.
“This is the first study showing this compound having a high efficiency in senolytic clearance,” said Liya Pi, assistant professor of pathology at Tulane University School of Medicine and corresponding author of the study. The drug works by degrading two survival proteins, BCL-xL and BCL-2, that senescent cells depend on to avoid natural cell death.
In laboratory tests, 753b proved approximately 14 times more potent than ABT263, a well-known senolytic that causes dangerous platelet drops. The new compound showed minimal platelet toxicity while maintaining superior effectiveness against senescent cells from different tissue types.
From Fatty Liver to Cancer Prevention
The research team tested 753b in STAM mice, an established model that mimics human MASLD progression from simple fat accumulation to inflammation, scarring, and eventually liver cancer. These mice develop the full spectrum of disease with 100% penetrance—making them ideal for studying intervention strategies.
Treatment results varied dramatically depending on timing. When researchers administered 753b during the transition from inflammation to early cancer development (equivalent to treating established but not end-stage disease in humans), the drug effectively reduced:
- Liver fat deposits by significant margins compared to untreated mice
- Scar tissue formation and inflammatory markers
- Tumor number and volume in cancer-prone animals
- Liver enzyme levels indicating cellular damage
However, early treatment during initial fat accumulation showed no benefit, and late treatment after tumors were established proved ineffective. This timing-dependent response suggests the drug works by preventing disease progression rather than reversing established damage.
Targeting the Root of Liver Damage
The study revealed that senescent cells accumulate primarily in periportal hepatocytes—liver cells positioned near blood vessel entry points that appear most vulnerable to metabolic stress. These zombie cells express high levels of senescence markers and inflammatory factors that drive disease progression.
“Chronic fatty liver disease is a global problem,” Pi explained. “Not only did the drug selectively target senescent cells and slow the progression of MASLD, it also halted the development of associated liver diseases as well as hepatocellular carcinoma.”
Hepatocellular carcinoma represents the most common form of liver cancer, with MASLD-related cases increasing rapidly as obesity rates climb worldwide. Currently, only one FDA-approved drug exists for treating the inflammatory stage of fatty liver disease, making 753b’s broad protective effects particularly noteworthy.
Safety Through Selectivity
One concern with senolytic therapies involves the potential for eliminating beneficial senescent cells that aid wound healing and tissue maintenance. The liver-specific accumulation of 753b could address this issue by sparing senescent cells in other organs that might serve protective functions.
The drug’s selectivity extends beyond tissue distribution. Laboratory studies confirmed that 753b cannot kill certain types of senescent cells, such as preadipocytes, that don’t depend on BCL-xL and BCL-2 for survival. This built-in selectivity could reduce unintended consequences compared to broader senolytic approaches.
Safety assessments in aged mice showed 753b reduced platelet counts to normal levels without causing the severe drops associated with similar compounds. Treated animals maintained stable body weight and showed no obvious pathological changes during treatment periods.
The research represents a collaboration between Tulane University, the University of Texas Health Science Center at San Antonio, and the University of Florida. While promising, Pi emphasized that “more research is needed but hopefully this is a potential tool that patients can one day use to control this disease.”
With MASLD cases expected to surge alongside global obesity trends, senolytic therapies like 753b could offer new strategies for preventing liver disease progression before irreversible damage occurs.
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