Calf muscle adaptation to peripheral vascular disease

Area of Science:

• Muscle physiology
• Vascular biology
• Exercise science

Background:

• Peripheral vascular disease (PVD) affects limb circulation.
• Previous theories suggested increased aerobic potential in PVD muscles.
• Understanding muscle adaptation in PVD is crucial for treatment.

Purpose of the Study:

• To investigate muscle fiber characteristics and enzyme activity in PVD patients.
• To determine if PVD muscles adapt by increasing aerobic capacity.
• To explore the impact of PVD severity on muscle morphology and function.

Main Methods:

• Histochemical analysis of 130 gastrocnemius muscle biopsies from PVD patients and controls.
• Biochemical analysis of aerobic and anaerobic enzymes in 30 PVD patients and 7 controls.
• Correlation of findings with ankle systolic pressure and PVD severity.

Main Results:

• PVD patients showed smaller Type 1 and Type 2 muscle fiber cross-sectional areas compared to controls.
• Decreased aerobic enzyme levels correlated with increased PVD severity.
• Intermittent claudication patients exhibited higher anaerobic enzyme levels.
• Evidence suggests a reduction in capillary numbers per muscle fiber.

Conclusions:

• Gastrocnemius muscle in PVD does not increase aerobic potential; it exhibits atrophy.
• Reduced mobility likely contributes to muscle atrophy in PVD.
• Training interventions may improve intermittent claudication by reversing muscle changes.