A very interesting study showing that far from being passive and strictly detrimental to health, fat cells are highly mobile and migrate readily through contraction/motility. These cells accumulate in areas with wounds or infection and release beneficial macrophages and peptides to help heal/cure these issues. In light of these properties, I suspect the fat accumulation in older age may be not just due to metabolism slowdown but also adaptive due to increased rates of chronic infections and proneness to poorly-healing wounds. This may explain part of the "obesity paradox", but I think the beneficial or detrimental effects of fat cells would depend largely on their fat composition - PUFA composition would have negative impact and SFA will be beneficial. This matches well with the clinical onservation that newborn babies with extra fat (which at birth is mostly saturated) fare much better when faced with neonatal infections and/or surgery than "lean" (read: emaciated) babies.
https://www.ncbi.nlm.nih.gov/pubmed/29486196
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https://www.ncbi.nlm.nih.gov/pubmed/29486196
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- Fat body cells actively migrate to wounds using a peristaltic mode of motility
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Fat body cells tightly seal the gap by forming lamellipodia around the wound margin
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Fat body cells collaborate with macrophages to clear wound debris
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Fat body cells locally release antimicrobial peptides at infected wounds