Study summary · research use only
Hyperpolarized [1-(13)C]Acetyl-l-Carnitine Probes Tricarboxylic Acid Cycle Activity In Vivo
Plain-language summary
Paraphrased from the published abstract below — not a verdict on whether anything works.
This study in rats used hyperpolarized [1-13C]acetyl-L-carnitine (ALCAR) as a noninvasive probe of cardiac tricarboxylic acid (TCA) cycle activity. The labeled substrate showed a 13C T1 value of 50.1 ± 0.8 s at 3 T and polarization levels of 21.3 ± 5.3%. The probe was used to analyze OXPHOS in rats under fed and fasted conditions, with [5-13C]glutamate detected and used to assess TCA cycle activity, compared to analogous experiments using hyperpolarized [1-13C]pyruvate. The authors describe this as the first study to demonstrate that hyperpolarized [1-13C]ALCAR enables direct analysis of mitochondrial function and TCA cycle activity in vivo.
Abstract
Mitochondrial oxidative phosphorylation (OXPHOS) is sensitive to a variety of biological factors, and dysregulated OXPHOS is observed during the development of numerous pathological conditions. ATP production via OXPHOS is intrinsically dependent on the availability of acetyl-coenzyme A (CoA), which can enter the tricarboxylic acid (TCA) cycle to drive the oxidative pathway. Acetyl-l-carnitine (ALCAR) is an interchangeable endogenous source of acetyl-CoA, and therefore, ALCAR-derived probes are uniquely positioned for the assessment of OXPHOS. In this report, we develop hyperpolarized (HP) [1-13C]ALCAR as a noninvasive probe to investigate cardiac TCA cycle activity in vivo. We initially synthesized the isotopically labeled substrate and demonstrated that the 13C nucleus maintained a suitable T1 value (50.1 ± 0.8 s at 3 T) and polarization levels (21.3 ± 5.3%) to execute in vivo metabolic measurements. HP [1-13C]ALCAR was employed for cardiac analyses of OXPHOS in rats under fed and fasted conditions. [5-13C]Glutamate was successfully detected, and the metabolite was used to analyze the TCA cycle activity in both nutritional states. These assessments were compared to analogous experiments with the HP [1-13C]pyruvate. Our report represents the first study to demonstrate that HP methods using [1-13C]ALCAR enable direct analyses of mitochondrial function and TCA cycle activity, which are fundamental to cardiac cell homeostasis.
pepmg summarizes the peer-reviewed literature and links to every source — it sells nothing, ships nothing, and gives no medical, dosing, or human-use guidance. Don't just trust this summary: follow the citation to its source and read it yourself. Research use only.