Selective diaphragmatic mitochondrial abnormalities in a patient with marked air flow obstruction.

There is increasing evidence that exercise overload induces changes in skeletal muscle structure and function. Recent studies suggest that muscle mitochondria could be involved either as the result or the origin of these changes. This study describes a case of a patient with marked air flow obstruction related to chronic obstructive pulmonary disease, in which large aggregates of mitochondria were found in diaphragm muscle fibers. Many of the mitochondria contained paracrystalline rectangular inclusions. Latissimus dorsi and intercostal muscles were also available for ultrastructural examination that showed, respectively, normal and moderately increased number of mitochondria with normal mitochondrial structure. This is the first known report of paracrystalline rectangular inclusions in respiratory skeletal muscle from a patient with chronic obstructive pulmonary disease.