Gerald F Watts1, Dick C Chan2, Jing Pang2, Louis Ma2, Qidi Ying2, Shashi Aggarwal3, Santica M Marcovina4, P Hugh R Barrett5. 1. Lipid Disorders Clinic, Department of Cardiology, Royal Perth Hospital, Perth, Australia; School of Medicine, Faculty of Health and Medical Sciences, University of Western Australia, Perth, Australia. Electronic address: gerald.watts@uwa.edu.au. 2. School of Medicine, Faculty of Health and Medical Sciences, University of Western Australia, Perth, Australia. 3. Linear Clinical Research Ltd, Perth, Australia. 4. Northwest Lipid Metabolism and Diabetes Research Laboratories, Division of Metabolism, Endocrinology, and Nutrition, Seattle, USA; Department of Medicine, University of Washington, Seattle, USA. 5. Faculty of Medicine and Health, University of New England, Armidale, Australia.
Abstract
BACKGROUND: Lipoprotein(a) (Lp(a)) is a low-density lipoprotein (LDL) particle containing apolipoprotein(a) (apo(a)) covalently linked to apolipoprotein B-100 (apoB). Statin-treated patients with elevated Lp(a) have an increased risk of atherosclerotic cardiovascular disease (ASCVD). Recent trials show that proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibition decreases Lp(a) and cardiovascular events, particularly in high risk patients with elevated Lp(a). We investigated the kinetic mechanism whereby alirocumab, a PCSK9 inhibitor, lowers Lp(a) in statin-treated patients with high Lp(a) and ASCVD. METHODS: The effects of 12-week alirocumab treatment (150 mg every 2 weeks) on apo(a) kinetics were studied in 21 patients with elevated Lp(a) concentration (>0.5 g/L). Apo(a) fractional catabolic rate (FCR) and production rate (PR) were determined using intravenous D3-leucine administration, mass spectrometry and compartmental modelling. All patients were on long-term statin treatment. RESULTS: Alirocumab significantly decreased plasma concentrations of total cholesterol (-39%), LDL-cholesterol (-67%), apoB (-56%), apo(a) (-25%) and Lp(a) (-22%) (P< 0.001 for all). Alirocumab also significantly lowered plasma apo(a) pool size (-26%, P <0.001) and increased the FCR of apo(a) (+28%, P< 0.001), but did not alter apo(a) PR, which remained significantly higher relative to a reference group of patients on statins with normal Lp(a) (P< 0.001). CONCLUSIONS: In statin-treated patients, alirocumab lowers elevated plasma Lp(a) concentrations by accelerating the catabolism of Lp(a) particles. This may be consequent on marked upregulation of hepatic receptors (principally for LDL) and/or reduced competition between Lp(a) and LDL particles for these receptors; the mechanism could contribute to the benefit of PCSK9 inhibition with alirocumab on cardiovascular outcomes.
BACKGROUND:Lipoprotein(a) (Lp(a)) is a low-density lipoprotein (LDL) particle containing apolipoprotein(a) (apo(a)) covalently linked to apolipoprotein B-100 (apoB). Statin-treated patients with elevated Lp(a) have an increased risk of atherosclerotic cardiovascular disease (ASCVD). Recent trials show that proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibition decreases Lp(a) and cardiovascular events, particularly in high risk patients with elevated Lp(a). We investigated the kinetic mechanism whereby alirocumab, a PCSK9 inhibitor, lowers Lp(a) in statin-treated patients with high Lp(a) and ASCVD. METHODS: The effects of 12-week alirocumab treatment (150 mg every 2 weeks) on apo(a) kinetics were studied in 21 patients with elevated Lp(a) concentration (>0.5 g/L). Apo(a) fractional catabolic rate (FCR) and production rate (PR) were determined using intravenous D3-leucine administration, mass spectrometry and compartmental modelling. All patients were on long-term statin treatment. RESULTS:Alirocumab significantly decreased plasma concentrations of total cholesterol (-39%), LDL-cholesterol (-67%), apoB (-56%), apo(a) (-25%) and Lp(a) (-22%) (P< 0.001 for all). Alirocumab also significantly lowered plasma apo(a) pool size (-26%, P <0.001) and increased the FCR of apo(a) (+28%, P< 0.001), but did not alter apo(a) PR, which remained significantly higher relative to a reference group of patients on statins with normal Lp(a) (P< 0.001). CONCLUSIONS: In statin-treated patients, alirocumab lowers elevated plasma Lp(a) concentrations by accelerating the catabolism of Lp(a) particles. This may be consequent on marked upregulation of hepatic receptors (principally for LDL) and/or reduced competition between Lp(a) and LDL particles for these receptors; the mechanism could contribute to the benefit of PCSK9 inhibition with alirocumab on cardiovascular outcomes.
Authors: Soo Ghee Yeoh; Jia Siang Sum; Jing Yi Lai; W Y Haniff W Isa; Theam Soon Lim Journal: J Cardiovasc Transl Res Date: 2021-08-31 Impact factor: 3.216
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Authors: Michael Szarek; Vera A Bittner; Philip Aylward; Marie Baccara-Dinet; Deepak L Bhatt; Rafael Diaz; Zlatko Fras; Shaun G Goodman; Sigrun Halvorsen; Robert A Harrington; J Wouter Jukema; Patrick M Moriarty; Robert Pordy; Kausik K Ray; Peter Sinnaeve; Sotirios Tsimikas; Robert Vogel; Harvey D White; Doron Zahger; Andreas M Zeiher; Ph Gabriel Steg; Gregory G Schwartz Journal: Eur Heart J Date: 2020-11-21 Impact factor: 29.983