Researchers at UCLA have identified senescent immune cells, dubbed 'zombie' cells, that accumulate in aging livers and contribute to fatty liver disease. By eliminating these cells in mice, the team reversed liver damage and reduced body weight, even on an unhealthy diet. The findings, published in Nature Aging, suggest similar mechanisms may drive human liver conditions.
UCLA scientists uncovered a population of senescent macrophages marked by p21 and TREM2 proteins that build up in the livers of older mice and those with high cholesterol. In young mice, only about 5% of liver macrophages showed this signature, rising to 60-80% in older animals, correlating with increased inflammation. Anthony Covarrubias, senior author and a UCLA professor, compared these cells to stalled cars causing widespread disruption in tissues despite their rarity. 'Just one stalled car can back up traffic for miles,' Covarrubias said. 'Now imagine five or ten of them slowly accumulating.'
