Using [1-(13) C]lactic acid for hyperpolarized (13) C MR cardiac studies

Area of Science:

• Metabolic Imaging
• Cardiovascular Magnetic Resonance Spectroscopy
• Hyperpolarized Contrast Agents

Background:

• Investigating cardiac metabolism in real-time is crucial for understanding heart disease.
• Hyperpolarized magnetic resonance (MR) techniques offer a non-invasive window into metabolic pathways.
• Lactate, a readily available metabolite, has potential as a substrate for these studies.

Purpose of the Study:

• To explore the feasibility of using hyperpolarized [1-(13) C]lactate for in vivo cardiac metabolism studies.
• To assess [1-(13) C]lactate as a potential alternative to [1-(13) C]pyruvate for cardiac MR.
• To evaluate the safety and clinical relevance of hyperpolarized [1-(13) C]lactate.

Main Methods:

• Neat [1-(13) C]lactic acid was hyperpolarized using dynamic nuclear polarization (DNP).
• Cardiac MR spectroscopy was performed in vivo in rats using hyperpolarized [1-(13) C]lactate and [1-(13) C]pyruvate.
• Dose-dependent responses of [1-(13) C]bicarbonate signal were analyzed.

Main Results:

• High polarization (16.7%) was achieved for [1-(13) C]lactate.
• [13]C-Bicarbonate was detected in vivo after infusion of both hyperpolarized [1-(13) C]lactate and [1-(13) C]pyruvate.
• A lower bicarbonate-to-substrate ratio was observed with [1-(13) C]lactate, and signal saturation occurred at higher doses.

Conclusions:

• Neat [1-(13) C]lactic acid is a viable alternative to [1-(13) C]pyruvate for cardiac hyperpolarized (13)C MR.
• Hyperpolarized [1-(13) C]lactate holds potential for non-invasive assessment of cardiac pyruvate dehydrogenase flux.
• This technique may be applicable to cardiac patients in the near future.