Acetyl-L-carnitine Supplementation Reverses the Age-related Decline in Carnitine Palmitoyltransferase 1 (CPT1) Activity in Interfibrillar Mitochondria Without Changing the L-carnitine Content in the Rat Heart
Overview
Authors
Affiliations
The aging heart displays a loss of bioenergetic reserve capacity partially mediated through lower fatty acid utilization. We investigated whether the age-related impairment of cardiac fatty acid catabolism occurs, at least partially, through diminished levels of L-carnitine, which would adversely affect carnitine palmitoyltransferase 1 (CPT1), the rate-limiting enzyme for fatty acyl-CoA uptake into mitochondria for β-oxidation. Old (24-28 mos) Fischer 344 rats were fed±acetyl-L-carnitine (ALCAR; 1.5% [w/v]) for up to four weeks prior to sacrifice and isolation of cardiac interfibrillar (IFM) and subsarcolemmal (SSM) mitochondria. IFM displayed a 28% (p<0.05) age-related loss of CPT1 activity, which correlated with a decline (41%, p<0.05) in palmitoyl-CoA-driven state 3 respiration. Interestingly, SSM had preserved enzyme function and efficiently utilized palmitate. Analysis of IFM CPT1 kinetics showed both diminished V(max) and K(m) (60% and 49% respectively, p<0.05) when palmitoyl-CoA was the substrate. However, no age-related changes in enzyme kinetics were evident with respect to L-carnitine. ALCAR supplementation restored CPT1 activity in heart IFM, but not apparently through remediation of L-carnitine levels. Rather, ALCAR influenced enzyme activity over time, potentially by modulating conditions in the aging heart that ultimately affect palmitoyl-CoA binding and CPT1 kinetics.
The onset and the development of cardiometabolic aging: an insight into the underlying mechanisms.
Sarkar S, Prasanna V, Das P, Suzuki H, Fujihara K, Kodama S Front Pharmacol. 2024; 15:1447890.
PMID: 39391689 PMC: 11464448. DOI: 10.3389/fphar.2024.1447890.
Zhou K, Tang M, Zhang W, Chen Y, Guan Y, Huang R Toxics. 2024; 12(4).
PMID: 38668511 PMC: 11053804. DOI: 10.3390/toxics12040288.
Urinary Metabolomics for the Prediction of Radiation-Induced Cardiac Dysfunction.
Li Y, Bansal S, Sridharan V, Bansal S, Jayatilake M, Fernandez J Metabolites. 2023; 13(4).
PMID: 37110184 PMC: 10146652. DOI: 10.3390/metabo13040525.
An AMP Kinase-pathway dependent integrated stress response regulates ageing and longevity.
Keizer H, Brands R, Seinen W Biogerontology. 2023; 24(4):443-455.
PMID: 36877293 DOI: 10.1007/s10522-023-10024-3.
Inhibits Lipid Deposition in Goat Intramuscular Preadipocytes.
Yang C, Li Q, Lin Y, Wang Y, Shi H, Huang L Genes (Basel). 2023; 14(2).
PMID: 36833367 PMC: 9956415. DOI: 10.3390/genes14020440.