Mitochondrial Myopathy Activates Capillary Growth

Mitochondrial DNA mutations spurs vascular endothelial growth factor in muscle

THURSDAY, Sept. 29 (HealthDay News) -- Patients with mitochondrial myopathy (MM) have excess capillary growth in muscle tissue, researchers reported this week at the annual meeting of the American Neurological Association in San Diego.

Tanja Taivassalo, Ph.D., of the University of Texas Southwestern Medical Center at Dallas, and colleagues assessed the oxidative capacity, muscle capillaries and vascular endothelial growth factor production in four patients with MM and four controls. Needle biopsies of the vastus lateralis were tested.

Peak oxidative capacity in patients was one-third that of control subjects, but overall capillary to muscle fiber area was two to three times higher in patients. The capillary to myofiber area was threefold higher in respiratory incompetent versus normal fibers.

"Our results suggest that impaired oxidative metabolism in MM due to mtDNA mutations activates capillary growth by a hypoxia independent mechanism," the researchers conclude.


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