Placenta growth factor is not required for exercise-induced angiogenesis

Area of Science:

• Physiology
• Molecular Biology
• Cardiovascular Research

Background:

• Angiogenesis, the formation of new blood vessels, is crucial for development and adult physiology.
• Placental growth factor (PlGF), a vascular endothelial growth factor (VEGF) family member, and its receptor Flt-1 are implicated in regulating angiogenesis.
• Dysregulation of angiogenesis is linked to pathological conditions like cancer, arthritis, and atherosclerosis.

Purpose of the Study:

• To investigate the role of PlGF in physiological angiogenesis induced by physical training.
• To analyze vascular adaptations in heart and skeletal muscles of wild-type and Plgf knockout mice after endurance exercise.
• To determine if PlGF is necessary for exercise-induced vascular remodeling.

Main Methods:

• Comparison of sedentary and trained wild-type and Plgf-/- mice.
• Analysis of heart/body weight ratio and citrate synthase activity.
• Assessment of capillary density, capillary-to-myocyte ratio, and intercapillary distance in muscle tissues.
• Measurement of PlGF protein levels after acute exercise.

Main Results:

• Sedentary Plgf-/- mice exhibited reduced capillary density in heart and skeletal muscles compared to wild-type controls.
• A 6-week training program significantly increased heart/body weight ratio, citrate synthase activity, vessel density, and capillary-to-myocyte ratio in both genotypes.
• Exercise training reduced intercapillary distance in both wild-type and Plgf-/- mice, indicating effective angiogenesis.
• Acute exercise did not alter PlGF protein levels in skeletal muscle.

Conclusions:

• PlGF is not required for the angiogenesis stimulated by prolonged physical training.
• Exercise-induced angiogenesis occurs independently of PlGF.
• The findings suggest PlGF's role in angiogenesis is primarily restricted to pathological contexts, not physiological responses to exercise.