Joseph L. Witztum

Oxidized phospholipids (OxPL) are generated at sites of oxidative stress and tissue injury, where they function as prototypic danger-associated molecular patterns that trigger inflammation, cell death, and tissue remodeling. The natural IgM antibody E06, and derivative formats such as E06-scFv, recognize the phosphocholine epitope on OxPL but not on native phospholipids, providing powerful tools to probe the biology of OxPL across cardiovascular and noncardiovascular disease. In this review, we summarize experimental and translational evidence implicating OxPL as mediators of atherogenesis, myocardial ischemia–reperfusion injury, nonalcoholic steatohepatitis and hepatocellular carcinoma, bone loss, lung fibrosis and acute lung injury, sepsis, neuroinflammation, and pain. In multiple murine models, genetic or passive approaches that express or deliver E06-based constructs neutralize OxPL, attenuate inflammation, improve tissue function, and reduce lesion burden, establishing OxPL as an actionable driver rather than a passive byproduct of oxidative stress. We further highlight how E06 has been leveraged to develop sensitive immunoassays for OxPL on apoB-containing lipoproteins and on Lp(a) (lipoprotein[a]; OxPL–apo[a]). These biomarkers consistently associate with incident and recurrent cardiovascular events and link OxPL biology to human lipoprotein metabolism, particularly the preferential enrichment of OxPL on Lp(a). We review emerging data on how established and novel therapies, including statins, PCSK9 (proprotein convertase subtilisin/kexin type 9) inhibitors, lipoprotein apheresis, and Lp(a)-targeted antisense and RNA-based agents, modulate OxPL, and discuss how these interventions may help test the OxPL hypothesis in outcomes trials. Finally, we outline key challenges and opportunities for translating OxPL-directed strategies to the clinic, including issues of specificity, immunogenicity, timing, and patient selection. Collectively, these insights position OxPL and its selective neutralization by E06-like antibodies as a unifying mechanism and promising therapeutic target across diverse inflammatory and cardiometabolic diseases.

BACKGROUND: Oxidized phospholipids on apolipoprotein B-100 (OxPL-apoB) reflect pro-inflammatory properties of Lp(a) (lipoprotein(a)). The effect of OxPL-apoB on major adverse cardiovascular events (MACE) in patients with acute coronary syndrome in recent the era is not known. METHODS: OxPL-apoB levels and Lp(a) were measured in 11 630 participants before and 5185 participants 4 months after randomization to alirocumab or placebo in the ODYSSEY OUTCOMES trial. Proportional hazards models adjusted for baseline covariates evaluated associations between log ₂ -transformed OxPL-apoB and Lp(a) with MACEs. Interactions between the 2 biomarkers and treatment were also evaluated. RESULTS: Participants were followed for a median 2.9 years; the median age was 58 years, and 23.9% were female. Alirocumab reduced median placebo-adjusted OxPL-apoB by 13.0% and Lp(a) by 26.2% (both P P =0.0034) for MACEs. Addition of Lp(a) to the model relegated the relationship of OxPL-apoB insignificant. In the alirocumab group, neither OxPL-apoB nor Lp(a) remained significantly associated with MACEs. A significant 3-way interaction was present among continuous log ₂ OxPL-apoB, Lp(a) stratified at the median, and treatment group on MACEs ( P _interaction =0.0023) so that, in the placebo group, increasing OxPL-apoB was associated with higher risk of MACEs when Lp(a) was below the median concentration but not above. In the alirocumab group, OxPL-apoB was not related to MACE risk irrespective of Lp(a) concentration. CONCLUSIONS: In patients with recent acute coronary syndrome receiving optimized statin treatment, elevated OxPL-apoB levels predicted MACEs, a relationship abrogated by alirocumab. The interaction of OxPL-apoB and Lp(a) in the placebo group indicates that OxPL-apoB independently predicts MACEs when Lp(a) levels are relatively low. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifiers: NCT001747 and NCT01663402.

BACKGROUND: Dyslipidemia increases cardiovascular disease risk, the leading cause of death worldwide. Under time-restricted feeding (TRF), wherein food intake is restricted to a consistent window of <12 hours, weight gain, glucose intolerance, inflammation, dyslipidemia, and hypercholesterolemia are all reduced in mice fed an obesogenic diet. LDLR (low-density lipoprotein receptor) mutations are a major cause of familial hypercholesterolemia and early-onset cardiovascular disease. METHODS: We subjected benchmark preclinical models, mice lacking LDLR-knockout or ApoE knockout to ad libitum feeding of an isocaloric atherogenic diet either ad libitum or 9 hours TRF for up to 13 weeks and assessed disease development, mechanism, and global changes in hepatic gene expression and plasma lipids. In a regression model, a subset of LDLR-knockout mice were ad libitum fed and then subject to TRF. RESULTS: TRF could significantly attenuate weight gain, hypercholesterolemia, and atherosclerosis in mice lacking the LDLR-knockout mice under experimental conditions of both prevention and regression. In LDLR-knockout mice, increased hepatic expression of genes mediating β-oxidation during fasting is associated with reduced VLDL (very-low-density lipoprotein) secretion and lipid accumulation. Additionally, increased sterol catabolism coupled with fecal loss of cholesterol and bile acids contributes to the atheroprotective effect of TRF. Finally, TRF alone or combined with a cholesterol-free diet can reduce atherosclerosis in LDLR-knockout mice. However, mice lacking ApoE, which is an important protein for hepatic lipoprotein reuptake do not respond to TRF. CONCLUSIONS: In a preclinical animal model, TRF is effective in both the prevention and regression of atherosclerosis in LDLR knockout mice. The results suggest TRF alone or in combination with a low-cholesterol diet can be a lifestyle intervention for reducing cardiovascular disease risk in humans.

Prolonged or excessive exposure to oxidized phospholipids (OxPLs) generates chronic inflammation. OxPLs are present in atherosclerotic lesions and can be detected in plasma on apolipoprotein B (apoB)-containing lipoproteins. When initially conceptualized, OxPL–apoB measurement in plasma was expected to reflect the concentration of minimally oxidized LDL, but, surprisingly, it correlated more strongly with plasma lipoprotein(a) (Lp(a)) levels. Indeed, experimental and clinical studies show that Lp(a) particles carry the largest fraction of OxPLs among apoB-containing lipoproteins. Plasma OxPL–apoB levels provide diagnostic information on the presence and extent of atherosclerosis and improve the prognostication of peripheral artery disease and first and recurrent myocardial infarction and stroke. The addition of OxPL–apoB measurements to traditional cardiovascular risk factors improves risk reclassification, particularly in patients in intermediate risk categories, for whom improving decision-making is most impactful. Moreover, plasma OxPL–apoB levels predict cardiovascular events with similar or greater accuracy than plasma Lp(a) levels, probably because this measurement reflects both the genetics of elevated Lp(a) levels and the generalized or localized oxidation that modifies apoB-containing lipoproteins and leads to inflammation. Plasma OxPL–apoB levels are reduced by Lp(a)-lowering therapy with antisense oligonucleotides and by lipoprotein apheresis, niacin therapy and bariatric surgery. In this Review, we discuss the role of role OxPLs in the pathophysiology of atherosclerosis and Lp(a) atherogenicity, and the use of OxPL–apoB measurement for improving prognosis, risk reclassification and therapeutic interventions.