Increased intrinsic mitochondrial function in humans with mitochondrial haplogroup H

Area of Science:

• Human physiology
• Mitochondrial genetics
• Exercise science

Background:

• Mitochondrial variants are hypothesized to influence maximal oxygen uptake (VO2max).
• The effect of mitochondrial variants on intrinsic mitochondrial respiratory capacity in human skeletal muscle remains unclear.

Purpose of the Study:

• To investigate the relationship between mitochondrial haplogroups and intrinsic mitochondrial function in human skeletal muscle.
• To determine if mitochondrial variants influence maximal oxygen uptake (VO2max).

Main Methods:

• Recruited 54 males to determine mitochondrial haplogroup, oxidative phosphorylation capacity (OXPHOS), and citrate synthase (CS) as a measure of mitochondrial content.
• Calculated intrinsic mitochondrial function as the ratio of OXPHOS capacity to mitochondrial content (CS).
• Assessed maximal oxygen uptake (VO2max).

Main Results:

• Mitochondrial haplogroup H exhibited 30% higher intrinsic mitochondrial function compared to haplogroup U.
• No significant relationship was found between mitochondrial haplogroups and VO2max.
• Skeletal muscle from individuals with mitochondrial haplogroup H demonstrated increased intrinsic mitochondrial function.

Conclusions:

• Mitochondrial haplogroup H is associated with enhanced intrinsic mitochondrial function in human skeletal muscle.
• Mitochondrial variants, as defined by haplogroups, do not appear to directly impact VO2max in this cohort.