Energy Metabolism and Mitochondrial Function

NoteChapter Abstract

Energy production impairment is a central feature of ME/CFS pathophysiology and likely underlies the characteristic fatigue and post-exertional malaise that define the illness. This chapter approaches cellular energy metabolism as a ten-step chain from substrate delivery to ATP utilization, asking at each step what normally happens, how much ATP is produced or gated, what has been documented in ME/CFS, what failure modes have been observed or mechanistically predicted, and what remains uninvestigated. The 2024 NIH deep phenotyping study by Walitt et al. (Walitt et al. 2024) provides important metabolomic data from cerebrospinal fluid analysis, linking energy metabolism dysfunction to neurological symptoms, and frames the chapter’s relevance to Chapter Integrative Models and Multi-System Pathophysiology. Four integrative hypotheses connecting multiple steps are developed in the final section.

NoteChapter Roadmap: How to Use This Chapter

For patients: read the ten-step chain overview and the consequences-of-energy-deficits section to understand why exertion causes the characteristic crash.

For caregivers: read the overview to understand the energy limits that drive pacing. The deeper biochemistry sections can be skimmed.

For clinicians: read the failure-mode sections relevant to the patient’s presentation, and the potential-interventions section for treatment-oriented content.

For researchers: read the ten steps in sequence, then the metabolic-trap hypothesis and the summary integrated model. The cross-cutting sections recur in Chapter Integrative Models and Multi-System Pathophysiology.

1 Contents

• The Energy Chain: Ten Steps from Substrate to ATP
• Step 1: Substrate Delivery — Glucose, Fatty Acid, and Oxygen Uptake
• Step 2: Glycolysis
• Step 3: Pyruvate Dehydrogenase Complex (PDC)
• Step 4: Carnitine Shuttle and Beta-Oxidation
• Step 5: Krebs Cycle — Enzyme-Level Failure Modes
• Step 6: Key Cofactors as Cross-Cutting Failure Modes
• Step 7: ATP Export — The Adenine Nucleotide Translocator (ANT)
• Step 8: Creatine Phosphate Shuttle
• Step 9: ROS Scavenging — The Mitochondrial Antioxidant Defense
• Step 10: Mitochondrial Dynamics and Biogenesis
• Summary: Uninvestigated Failure Modes with Therapeutic Implications
• Integrative Reference Tables
• Cross-Cutting Mechanisms
• Cross-Cutting Hypotheses
• Consequences of Energy Deficits
• Selective Energy Dysfunction: The CNS-Dependency Hypothesis
• Amino Acid Metabolism and Tryptophan Pathway
• Carbohydrate Metabolism and Lactate
• Catecholamine Metabolism: NIH Study Findings
• The "Metabolic Trap" Hypothesis
• Compartmental Energy Models
• Potential Interventions
• Energy Utilization Beyond ATP Production
• Summary: Integrated Metabolic Model
• Neurosteroid Cross-Talk with Mitochondrial Bioenergetics
• Brain Energy Metabolism: Cross-Disease Convergent Framework
• Prefrontal Energy Failure as the Unifying Substrate of ADHD-Like Executive Dysfunction in ME/CFS

References

Walitt, Brian, Komudi Singh, Samuel R LaMunion, Mark Hallett, Sandra Jacobson, Kong Chen, Yoshihisa Enose-Akahata, et al. 2024. “Deep Phenotyping of Post-Infectious Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.” Nature Communications 15 (1): 907. https://doi.org/10.1038/s41467-024-45107-3.