In human skeletal muscle, mitochondrial ceramide accumulation is specifically associated with reduced abundance of electron transport chain complex I subunits, particularly those in the N- and Q-modules, which are critical for NADH oxidation and coenzyme Q binding, suggesting a structural mechanism for mitochondrial dysfunction in insulin resistance.

When too much ceramide builds up inside muscle cell energy factories, it pulls away a key molecule called coenzyme Q, which causes critical parts of the energy-making machinery to fall apart. This specifically breaks down the sections that handle energy from sugar and connect to the next step in energy production, reducing the cell's ability to make energy and causing insulin resistance.