Satellite cell distance to its nearest capillary is inversely associated with muscle mass and strength in persons with COPD

<bold>Purpose:</bold> Satellite cells (SCs) play a key role in muscle tissue reconditioning. The spatial relationship between SCs and capillaries is implied to be important for SC function. We compared this spatial relationship in persons with COPD vs. healthy adults, and assessed its association with leg lean mass and function in persons with COPD. <bold>Methods:</bold> A m. <italic>vastus lateralis</italic> biopsy was obtained from 18 persons with COPD (8f/10m, 66±5y) and 18 age-matched healthy adults (8f/10m, 68±5y). Type I and II muscle fiber SC content, capillary-to-fiber ratio (C/F<italic>i</italic>) and SC distance to its nearest capillary was assessed via immunohistochemistry. Quadriceps strength (QS), endurance (QE) and leg lean mass (LM) were assessed in persons with COPD. <bold>Results:</bold> Fig 1 shows C/F<italic>i</italic> and SC content. Type I, but not type II (P=0.150), muscle fiber SC distance to its nearest capillary was greater in persons with COPD vs. healthy adults (21.3±4.8 vs. 16.1±3.5µm, P=0.001), and was associated with LM (r=-0.520), QS (r=-0.641) and non-significantly with QE (r=-0.415; Fig 1) in persons with COPD. <fig><object-id>erj;64/suppl_68/PA1663/F1</object-id><object-id>F1</object-id><object-id>F1</object-id><graphic></graphic></fig> <bold>Conclusion:</bold> Whereas muscle fiber capillarization was lower in persons with COPD, no difference was observed in SC number with age-matched healthy adults. The greater distance of SCs to their nearest capillary may play an important role in the impaired muscle and SC function, and reconditioning response often observed in persons with COPD.