Aerobic training workload affects human endothelial cells redox homeostasis

Area of Science:

• Exercise physiology
• Cellular biology
• Biochemistry

Background:

• Moderate aerobic exercise is known to reduce oxidative stress.
• Intense physical activity can paradoxically increase oxidative stress.
• The impact of varying exercise volumes on oxidative stress markers and cellular responses remains unclear.

Purpose of the Study:

• To investigate the effects of different exercise loads on oxidative stress markers.
• To examine the response of human endothelial cells (EC) to sera from triathletes with varying training volumes.
• To identify potential biomarkers for monitoring exercise-induced adaptations.

Main Methods:

• Human endothelial cells (Eahy-926) were cultured with sera from two triathlete groups: lower volume (T1) and higher volume (T2).
• Cells were exposed to oxidative stress conditions.
• Oxidative stress markers (nitric oxide, catalase, thiobarbituric acid reactive substances, superoxide dismutase) and cellular responses (survival, proliferation, senescence) were analyzed.
• Enzyme activity inhibition (catalase) and Sirt1 activity were assessed.

Main Results:

• Triathletes in the lower volume group (T1) exhibited higher serum nitric oxide and lower catalase activity compared to the higher volume group (T2).
• Endothelial cells conditioned with T1 serum (T1-EC) demonstrated enhanced survival, proliferation, and reduced senescence versus T2-EC, both before and after induced oxidative stress.
• T1-EC showed increased Sirt1 activity post-oxidative stress, unlike T2-EC, and required less catalase to counteract oxidative damage.

Conclusions:

• The beneficial effects of aerobic exercise on endothelial cells are diminished with increased training workload.
• Serum catalase activity can serve as a reliable marker for supervising exercise volume and its impact on oxidative stress.
• Lower volume training appears more effective in promoting endothelial cell resilience against oxidative stress.