Fibre morphology, intramyocellular lipid content and 3D capillary architecture in human postural, respiratory and locomotor muscles in type 2 diabetes mellitus

; p < 0.0001). Fibre-type profiles were similar, except for elevated 2a/2x hybrids in T2DM VL (p = 0.014). Mean fibre diameters were preserved, though type 1 fibres were larger in T2DM SC (p = 0.0238). IMCL was higher in T2DM SC and EXT (p < 0.05), with non-significant differences in VL and DIA. Type 1 and 2a fibres had higher IMCL than glycolytic fibres, with no group-by-fibre-type interaction. BMI strongly predicted VL IMCL (p < 0.0001), while age was negatively associated with IMCL in respiratory muscles (p ≤ 0.05). Capillary length per fibre volume was selectively reduced in DIA (p = 0.0115); other indices were preserved, except for higher anisotropy in EXT (p = 0.0495). Overall, these functionally diverse muscles showed subtle muscle-specific remodelling in T2DM, with adiposity-linked IMCL accumulation and reduced DIA capillary supply, although findings should be interpreted in the context of the post-mortem study.