The failing heart's secret problem isn't blood - it's energy


The heart is the body's most demanding organ. It beats over 100,000 times per day, never resting, never pausing - and to do so, it consumes more energy per gram of tissue than any other organ in the human body. Under normal conditions, approximately 70% of that energy comes from fatty acid oxidation. In heart failure, this elegant metabolic machinery breaks down: the heart reverts to a fetal-like pattern of glucose dependence, mitochondria shrink and malfunction, and energy supply falls catastrophically short of demand. The result is a failing pump.

A 2024 study published in Circulation (Xu et al., PMID: 37961903) - one of the most prestigious cardiovascular journals in the world - demonstrated that SLU-PP-332 and its structural analogue SLU-PP-915 can reverse these pathological changes in a pressure overload-induced heart failure mouse model.

Key Findings

• Restoration of fatty acid oxidation

SLU-PP-332 treatment upregulated CPT1 and downstream fatty acid oxidation enzymes in cardiomyocytes, restoring the heart's preferred fuel source and reducing pathological metabolic remodelling.

• Improved cardiac function

Treated animals showed measurable improvement in left ventricular ejection fraction (LVEF) and reduced cardiac hypertrophy - the abnormal thickening of the heart wall that characterises advanced heart failure. Think of it as shrinking an overworked, swollen muscle back to its efficient, lean form.

• Mitochondrial biogenesis and ultrastructure

Electron microscopy revealed that ERR agonism preserved mitochondrial density and cristae integrity in cardiomyocytes - the inner membrane folds that are the actual sites of ATP production. Damaged or absent cristae are a hallmark of heart failure; SLU-PP-332 appeared to protect and partially restore them.

• Gene expression changes

RNA sequencing confirmed upregulation of PGC-1α, TFAM, COX5A, and genes encoding fatty acid oxidation enzymes - the same cluster activated by aerobic exercise training in the healthy heart.

Why This Matters

Heart failure affects over 64 million people globally, with a 5-year mortality rate exceeding 50% - worse than many cancers. Current therapies reduce workload on the failing heart but do not address the underlying metabolic dysfunction. SLU-PP-332 represents a mechanistically distinct approach: instead of reducing demand, it restores the cellular capacity to meet it.

Cardiomyocytes are among the highest-expressing cells for both ERRα and ERRγ in the human body. This means the heart is exquisitely primed to respond to ERR agonism - making it one of the most promising therapeutic targets for this class of compounds.

Caution and Context

All data to date are preclinical (mouse models). Translation to human cardiac physiology requires rigorous clinical trials. Nonetheless, the mechanistic coherence - high ERR expression in the heart, well-characterised metabolic dysfunction in failure, and demonstrated functional rescue with SLU-PP-332 - provides a compelling scientific rationale for further investigation.

Warning:
SLU-PP-332 is a research compound not approved for human use. This content is produced exclusively for educational and informational purposes. Nothing contained herein constitutes or should be interpreted as medical advice, a clinical recommendation, a diagnostic opinion, or an endorsement of any specific treatment, supplement, or intervention. Always consult a qualified and licensed medical professional before making decisions regarding your health, supplementation, or medical care. The author and publisher of this content accept no liability for any actions taken or not taken based on the information provided herein.

Bibliography & Sources

Xu W, Billon C, Li H, et al. Novel Pan-ERR Agonists Ameliorate Heart Failure Through Enhancing Cardiac Fatty Acid Metabolism and Mitochondrial Function. Circulation. 2024;149(3):227–250. doi:10.1161/CIRCULATIONAHA.123.066542. PMID: 37961903. 

Billon C, Sitaula S, Banerjee S, et al. Synthetic ERRα/β/γ Agonist Induces an ERRα-Dependent Acute Aerobic Exercise Response and Enhances Exercise Capacity. ACS Chemical Biology. 2023;18(4):756–771. doi:10.1021/acschembio.2c00720. PMID: 36988910. 

Billon C, Schoepke E, Avdagic A, et al. A Synthetic ERR Agonist Alleviates Metabolic Syndrome. Journal of Pharmacological and Experimental Therapeutics. 2024;388(2):232–240. doi:10.1124/jpet.123.001733. PMID: 37739806. 

Okda HE, Zhao P, Hayes M, et al. Chemical Optimization of the Exercise Mimetic SLU-PP-332 Enables Insight into Estrogen-Related Receptor Signaling. International Journal of Biological Macromolecules. 2026;355:151450. doi:10.1016/j.ijbiomac.2026.151450. PMID: 41850449. 

de Souza-Lima J, Astrosa-Martin BD, et al. Pharmacological Activation of ERRα/β/γ as an Exercise Mimetic: Potential Therapeutic Applications. Revista Médica de Chile. 2026;154(2):237–245. doi:10.4067/s0034-98872026000200237. PMID: 42024694.

This article is for informational purposes only and is not intended as medical advice. It should not replace professional medical assessment, diagnosis, or treatment. If you have health concerns, please consult a qualified healthcare professional.