Available online 5 December 2022, 101651

Reactive dicarbonyl scavenging with PPM prevents atherosclerosis in Ldlr-/- mice.

PPM improves insulin sensitivity and decreases hepatic fat in male Ldlr-/- mice.

PPM increases the net cholesterol capacity of HDL from Ldlr-/- mice.

PPM promotes plaque stability as evidenced by increased efferocytosis, Tregs, and collagen.

PPM prevents monocytosis by impairing CD11b+monocyte and CD34+HSPC proliferation.

Oxidative stress contributes to the development of insulin resistance (IR) and atherosclerosis. Peroxidation of lipids produces reactive dicarbonyls such as Isolevuglandins (IsoLG) and malondialdehyde (MDA) that covalently bind plasma/cellular proteins, phospholipids, and DNA leading to altered function and toxicity. We examined whether scavenging reactive dicarbonyls with 5'-O-pentyl-pyridoxamine (PPM) protects against the development of IR and atherosclerosis in Ldlr-/- mice.

Male or female Ldlr-/- mice were fed a western diet (WD) for 16 weeks and treated with PPM versus vehicle alone. Plaque extent, dicarbonyl-lysyl adducts, efferocytosis, apoptosis, macrophage inflammation, and necrotic area were measured. Plasma MDA-LDL adducts and the in vivo and in vitro effects of PPM on the ability of HDL to reduce macrophage cholesterol were measured. Blood Ly6Chi monocytes and ex vivo 5-ethynyl-2’-deoxyuridine (EdU) incorporation into bone marrow CD11b+ monocytes and CD34+ hematopoietic stem and progenitor cells (HSPC) were also examined. IR was examined by measuring fasting glucose/insulin levels and tolerance to insulin/glucose challenge.

PPM reduced the proximal aortic atherosclerosis by 48% and by 46% in female and male Ldlr-/- mice, respectively. PPM also decreased IR and hepatic fat and inflammation in male Ldlr-/- mice. Importantly, PPM decreased plasma MDA-LDL adducts and prevented the accumulation of plaque MDA- and IsoLG-lysyl adducts in Ldlr-/- mice. In addition, PPM increased the net cholesterol efflux capacity of HDL from Ldlr-/- mice and prevented both the in vitro impairment of HDL net cholesterol efflux capacity and apoAI crosslinking by MPO generated hypochlorous acid. Moreover, PPM decreased features of plaque instability including decreased proinflammatory M1-like macrophages, IL-1β expression, myeloperoxidase, apoptosis, and necrotic core. In contrast, PPM increased M2-like macrophages, Tregs, fibrous cap thickness, and efferocytosis. Furthermore, PPM reduced inflammatory monocytosis as evidenced by decreased blood Ly6Chi monocytes and proliferation of bone marrow monocytes and HSPC from Ldlr-/- mice.

PPM has pleotropic atheroprotective effects in a murine model of familial hypercholesterolemia, supporting the therapeutic potential of reactive dicarbonyl scavenging in the treatment of IR and atherosclerotic cardiovascular disease.

Cholesterol efflux

high-density lipoprotein (HDL)

malondialdehyde (MDA)

macrophage

myeloperoxidase (MPO)

5'-O-pentyl-pyridoxamine (PPM)

C-C chemokine receptor 2

5-ethynyl-2’-deoxyuridine

Familial hypercholesterolemia

Glucose tolerance test

Hematopoietic stem and progenitor cells

High density lipoprotein

Homeostatic model assessment for insulin resistance

Insulin tolerance test

Isolevuglandins LDL, Low density lipoprotein

neutrophil extracellular traps

5'-O-pentyl-pyridoxamine

Reactive oxygen species

Reverse cholesterol transport

© 2022 The Author(s). Published by Elsevier GmbH.