What is the clinical evidence from this study?

Study design: RCT. Population: Healthy (n=23). Intervention: Cardiolipin vs. Placebo solution. Primary outcome: ADP-stimulated Complex I-dependent respiration (pmol s-1 mg-1) (95% CI 1.49-29.94, p=0.032).

What question did this study set out to answer?

This research aims to investigate how elevated cardiolipin affects mitochondrial respiration and aerobic capacity in skeletal muscle.

April 22, 2026Open Access

Intraperitoneal Administration of Cardiolipin Enhances Mitochondrial Respiration in Skeletal Muscle of Male Mice

Key Result

Intraperitoneal administration of cardiolipin significantly increased ADP-stimulated Complex I-dependent mitochondrial respiration in skeletal muscle of male mice compared to placebo.

Key Points

This research aims to investigate how elevated cardiolipin affects mitochondrial respiration and aerobic capacity in skeletal muscle.
Male C57BL/6 mice received either cardiolipin injections or a placebo for 6 weeks.
Aerobic capacity was evaluated by measuring time to exhaustion during treadmill running.
Mitochondrial respiratory capacity was assessed using high-resolution respirometry post-intervention.
Mice receiving cardiolipin showed increased oxygen consumption in skeletal muscle compared to controls.
No significant differences in mitochondrial density were observed, indicating improved respiratory efficiency.
The results suggest cardiolipin enhances mitochondrial function without increasing the number of mitochondria.

Study Design

Type

RCT (n=23)

Randomization

Randomized

Multicenter

Structured PICO

Does intraperitoneal cardiolipin administration improve aerobic capacity and mitochondrial respiratory function in male mice?

Population

Male C57BL/6 mice aged 6-7 months (n=23)

Intervention

Cardiolipin 0.1 mL (0.5 mg/mL) via intraperitoneal injection twice weekly for 6 weeks

Comparator

Placebo solution (physiological salt solution with matched ionic composition, pH, and osmolarity) via intraperitoneal injection twice weekly for 6 weeks

Outcome

Aerobic capacity (time to exhaustion during treadmill running) and mitochondrial respiratory capacity (oxygen consumption via high-resolution respirometry)surrogate

Exogenous cardiolipin administration enhances skeletal muscle mitochondrial respiratory capacity in mice without altering mitochondrial density, though it does not translate to improved functional aerobic capacity.

Main Result

Absolute Event Rate: 46.39% vs 30.68%

p-value: p=0.032

Limitations

Treadmill protocol was a constant-speed, time-to-exhaustion test at submaximal workload, not providing a direct measure of VO2max
Absence of direct quantification of cardiolipin levels in plasma, skeletal muscle, or mitochondrial fractions
Male-only design restricts generalizability and does not account for sex-specific differences
Duration of the experimental period (6 weeks) might not have fully captured longer-term impacts
Absence of a direct measure of cardiac output
Muscle wet weight was not collected

Abstract

Purpose: Cardiolipin is a phospholipid located in the inner mitochondrial membrane and is released following myocardial ischemia–reperfusion injury. While cardiolipin has documented effects in several tissues, its impact on skeletal muscle function and mitochondrial respiration remains unclear. The purpose of this study was to investigate the effects of exogenously elevated cardiolipin on aerobic capacity and mitochondrial respiratory function in skeletal muscle using a mouse model. Methods: Male C57BL/6 mice were randomized into an experimental group (n = 11) receiving cardiolipin injections and a control group (n = 12) receiving a placebo solution. Mice were injected twice weekly for 6 weeks with 0.1 mL of cardiolipin (0.5 mg/mL) or placebo. Voluntary running distance was monitored throughout the intervention. Aerobic capacity was assessed at baseline, week 3, and week 6 by measuring time to exhaustion during treadmill running at a constant speed of 16 m min − 1 . Following the intervention, mice were euthanized, the vastus lateralis muscle was excised, and mitochondrial respiratory capacity was evaluated using high-resolution respirometry. Mitochondrial density was assessed by immunoblotting. Results: Mice receiving cardiolipin exhibited increased skeletal muscle oxygen consumption compared with controls. No differences in mitochondrial density were observed between groups, suggesting that the enhanced oxygen consumption was not associated with increased mitochondrial content but may instead reflect alterations in mitochondrial respiratory efficiency. Conclusion: Exogenously elevated cardiolipin is associated with enhanced skeletal muscle mitochondrial respiratory function without altering mitochondrial density, which may indicate improved mitochondrial efficiency. These findings provide novel insight into the potential role of cardiolipin in skeletal muscle energy metabolism and aerobic performance. Future studies should explore the combined effects of cardiolipin administration and exercise training on skeletal muscle respiratory capacity and further investigate the underlying mechanisms. Keywords: cardiolipin, OXPHOS, ATP production, aerobic capacity, respiratory efficiency

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