{
  "id": 5613376,
  "title": "Energy-hungry tissues expand cleanup crews to clear worn-out mitochondria",
  "url": "https://urgent.news/2026/09/04/energy-hungry-tissues-expand-cleanup-crews-to-clear-worn-out",
  "topic": "science",
  "section": "Science",
  "published": "2026-09-04T18:00:05.000Z",
  "source": {
    "name": "Medical Xpress",
    "slug": "medical-xpress",
    "url": "https://medicalxpress.com/news/2026-09-energy-hungry-tissues-cleanup-crews.html"
  },
  "original_language": "en",
  "account": "Energy-demanding tissues like heart muscle, skeletal muscle, and brown fat require significant energy and produce substantial waste in the form of damaged mitochondria. To manage this waste, these tissues have evolved a system in which large numbers of immune cells called macrophages serve as cleanup crews. The size of this macrophage population scales with the metabolic activity of each tissue, ensuring that the body can effectively eliminate waste while meeting high energy demands. Researchers from UC San Francisco, Yale University, Pompeu Fabra University, and the Spanish National Center for Cardiovascular Research have discovered that fibroblasts, structural cells, play a crucial role in this process. As mitochondrial activity increases, fibroblasts proliferate and secrete signals that prompt macrophages to multiply, thereby expanding the clearance crew. When macrophages fail to clear the waste, tissues suffer - heart muscle weakens and pumps less effectively, skeletal muscle loses strength, and brown fat fails to generate heat. This waste management system operates in both mice and humans, suggesting that targeting it could help maintain tissue function as we age.",
  "summary": "The body's heart muscle (for pumping blood), skeletal muscle (for movement and posture) and brown fat (for heat production) each require a lot of energy and make a lot of waste. That waste needs to be managed.",
  "key_points": [
    "Energy-demanding tissues like heart muscle and brown fat produce substantial waste.",
    "Macrophages act as cleanup crews, scaling with tissue metabolic activity.",
    "Fibroblasts proliferate to secrete signals that expand macrophage population."
  ],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}