Clinical trials to improve outcomes in patients with elevated Lp(a) undergoing PCI: The time has arrived

Reactive Dicarbonyl Scavenging with 2-Hydroxybenzylamine Improves MASH

Background: Products of lipid peroxidation include a number of reactive lipid aldehydes including reactive dicarbonyl electrophiles (DEs) and contribute to disease processes. DEs play a significant role in the development and progression of metabolic-associated steatotic liver disease (MASLD) by contributing to oxidative stress, inflammation, protein dysfunction, and mitochondrial impairment. Reducing DE stress may be a potential strategy for managing MASLD. We hypothesized that the DE scavenger 2-hydroxybenzylamine (2-HOBA) would reduce liver injury by reducing liver protein adduct formation by DE in mouse models of MASLD. Methods: Protein adducts were measured in human livers by immunohistochemistry and immunoblot. The effects of 2-HOBA were assessed in two different mouse models of MASLD. Results: Isolevuglandin (IsoLG) protein adducts were increased in MASH-staged human livers relative to histologically normal controls. Diet-Induced Animal Model of Nonalcoholic Fatty Liver Disease (DIAMOND) mice treated with 2-HOBA exhibited significantly lower fibrosis scores (* p = 0.012) and reduced liver transaminases (AST, p = 0.03) and ALT, p = 0.012) by over 40%. In STAM (Stelic Animal Model) mice, 2-HOBA improved NAFLD activity scores (p = 0.03, NAS), hyperglycemia, and inflammatory cytokines and reduced serum F2-isoprostanes (IsoPs) by 30%, p = 0.05. These improvements were absent mRNA changes in hepatic antioxidant enzymes (Cat, Gpx1, or Sod2) or ROS-generating proteins (p22PHOX, p47PHOX, NOX4 or COX1). Conclusions: DE scavenging with 2-HOBA may be a promising therapeutic strategy for managing MASLD. While findings are currently limited to male mice, a nutraceutical that reduces liver fibrosis could significantly improve the management of MASH by offering a non-invasive treatment option to potentially slow or reverse liver scarring, delay progression to cirrhosis, and improve patient outcomes, while also providing a potential treatment option for patients who may not be suitable for other interventions like liver transplantation.

Lipoprotein(a), platelet function and cardiovascular disease

Lipoprotein(a) (Lp(a)) is associated with atherothrombosis through several mechanisms, including putative antifibrinolytic properties. However, genetic association studies have not demonstrated an association between high plasma levels of Lp(a) and the risk of venous thromboembolism, and studies in patients with highly elevated Lp(a) levels have shown that Lp(a) lowering does not modify the clotting properties of plasma ex vivo. Lp(a) can interact with several platelet receptors, providing biological plausibility for a pro-aggregatory effect. Observational clinical studies suggest that elevated plasma Lp(a) concentrations are associated with worse long-term outcomes in patients undergoing revascularization. Furthermore, in these patients, those with elevated plasma Lp(a) levels derive more benefit from prolonged dual antiplatelet therapy than those with normal Lp(a) levels. The ASPREE trial in healthy older individuals treated with aspirin showed a reduction in ischaemic events in those who had a single-nucleotide polymorphism in LPA that is associated with elevated Lp(a) levels in plasma, without an increase in bleeding events. In this Review, we re-examine the role of Lp(a) in the regulation of platelet function and suggest areas of research to define further the clinical relevance to cardiovascular disease of the observed associations between Lp(a) and platelet function.

Lipoprotein apheresis affects the concentration of extracellular vesicles in patients with elevated lipoprotein (a)

Lipoprotein apheresis (LA) is a therapeutic option for hyperlipoproteinemia(a) (hyper-Lp(a)) and atherosclerotic cardiovascular disease (ASCVD). LA improves blood rheology, reduces oxidative stress parameters and improves endothelial function. The underlying molecular mechanisms of LA beneficial effects are unknown, but it has been suggested that LA exhibits multiple activities beyond simply removing lipoproteins. We hypothesized that LA removes not only lipoproteins, but also extracellular vesicles (EVs). To test this hypothesis, we performed a prospective study in 22 patients undergoing LA for hyper-Lp(a) and ASCVD. Different EVs subtypes were measured before and directly after LA, and after 7 days. We used calibrated flow cytometry to detect total particle concentration (diameter >  ~ 100 nm), total lipoproteins concentration (diameter > 200 nm, RI > 1.51), total EV concentration (diameter > 200 nm, RI < 1.41), concentrations of EVs derived from erythrocytes (CD235a+; diameter > 200 nm, RI < 1.41), leukocytes (CD45+; diameter > 200 nm, RI < 1.41) and platelets (CD61+, PEVs; diameter > 200 nm, RI < 1.41). LA reduced the concentrations of all investigated EVs subtypes and lipoproteins. Lp(a) concentration was lowered by 64.5% [(58% - 71%); p < 0.001]. Plasma concentrations of EVs > 200 nm in diameter derived from platelets (CD61 +), leukocytes (CD45+) and erythrocytes (CD235a+) decreased after single LA procedure by 42.7% [(12.8-54.7); p = 0.005], 42.6% [(29.7-54.1); p = 0.030] and 26.7% [(1.0-62.7); p = 0.018], respectively, compared to baseline. All EV subtypes returned to the baseline concentrations in blood plasma after 7 days. To conclude, LA removes not only Lp(a), but also cell-derived EVs, which may contribute to LA beneficial effects.