👤 Chiara Macchi

The relationship between plasma lipoprotein(a) [Lp(a)] levels and metabolic dysfunction-associated steatotic liver disease (MASLD) remains unclear. The aim of this study was to examine the combined effects of Lp(a) levels on liver and vascular damage. The study was conducted using the Liver-Bible cohort of individuals with metabolic dysfunction (n = 859, 808 with genomic information) and the Milan Biobank (n = 6963). Genome-wide association studies (GWAS) and polygenic risk scores (PRS) were used to evaluate the inherited factors influencing plasma Lp(a) levels. In the Liver-Bible cohort, genetic variation in the LPA gene was the strongest determinant of Lp(a), followed by liver stiffness measurement (LSM). Additionally, circulating Lp(a) levels, but not genetic predisposition, were inversely related to LSM, suggesting that MASLD severity may affect Lp(a) secretion. Among participants with more severe insulin resistance (n = 250), Lp(a) levels (odds ratio 6.7, 95% CI 1.0-53.0, p = 0.046) and LSM (odds ratio 13.7, 95% CI 1.4-172.2, p = 0.023) were associated with greater prevalence of carotid atherosclerotic plaques, regardless of traditional cardiovascular risk factors. In the Milan Biobank, genetically predicted higher Lp(a) levels tended to increase the risk of liver-related outcomes, whereas genetically predicted MASLD was associated with lower circulating Lp(a) levels. The results of this study suggest that liver damage is more likely the cause of reduced plasma Lp(a) levels rather than a consequence. Assessing plasma Lp(a) levels and the extent of liver damage could improve the prediction of vascular damage. Show less

The high occurrence of atherosclerotic cardiovascular disease (ASCVD) events is still a major public health issue. Although a major determinant of ASCVD event reduction is the absolute change of low-density lipoprotein-cholesterol (LDL-C), considerable residual risk remains and new therapeutic options are required, in particular, to address triglyceride-rich lipoproteins and lipoprotein(a) [Lp(a)]. In the era of Genome Wide Association Studies and Mendelian Randomization analyses aimed at increasing the understanding of the pathophysiology of ASCVD, RNA-based therapies may offer more effective treatment options. The advantage of oligonucleotide-based treatments is that drug candidates are targeted at highly specific regions of RNA that code for proteins that in turn regulate lipid and lipoprotein metabolism. For LDL-C lowering, the use of inclisiran - a silencing RNA that inhibits proprotein convertase subtilisin/kexin type 9 (PCSK9) synthesis - has the advantage that a single s.c. injection lowers LDL-C for up to 6 months. In familial hypercholesterolemia, the use of the antisense oligonucleotide (ASO) mipomersen, targeting apolipoprotein (apoB) to reduce LDL-C, has been a valuable therapeutic approach, despite unquestionable safety concerns. The availability of specific ASOs lowering Lp(a) levels will allow rigorous testing of the Lp(a) hypothesis; by dramatically reducing plasma triglyceride levels, Volanesorsen (APOC3) and angiopoietin-like 3 (ANGPTL3)-LRx will further clarify the causality of triglyceride-rich lipoproteins in ASCVD. The rapid progress to date heralds a new dawn in therapeutic lipidology, but outcome, safety and cost-effectiveness studies are required to establish the role of these new agents in clinical practice. Show less

The cholesteryl ester transfer protein (CETP) system moves cholesteryl esters (CE) from high density lipoproteins (HDL) to lower density lipoproteins, i.e. very low-density lipoprotein (VLDL) and low-density lipoprotein (LDL) in exchange for triglycerides (TGs). This shuttle process will ultimately form complexes facilitating a bidirectional exchange of CE and TGs, the end process being CE delivery to catabolic sites. The CETP system is generally characteristic of higher animal species; lower species, not provided with this system, have higher and enlarged HDL enriched with apo E, suitable for tissue receptor interaction. Discovery of the CETP system has led to the development of agents interfering with CETP, thus elevating HDL-C and potentially preventing cardiovascular (CV) disease. Activation of CETP leads instead to reduced HDL-C levels, but also to an enhanced removal of CE from tissues. CETP antagonists are mainly small molecules (torcetrapib, anacetrapib, evacetrapib, dalcetrapib) and have provided convincing evidence of a HDL-C raising activity, but disappointing results in trials of CV prevention. In contrast, the CETP agonist probucol leads to HDL-C lowering followed by an increment of tissue cholesterol removal (reduction of xanthomas, xanthelasmas) and positive findings in secondary prevention trials. The drug has an impressive anti-inflammatory profile (markedly reduced interleukin-1β expression). Newer agents, some of natural origin, have additional valuable pharmacodynamic properties. The pharmacological approach to the CETP system remains enigmatic, although the failure of CETP antagonists has dampened enthusiasm. Studies on the system, a crossroad for any investigation on cholesterol metabolism, have however provided crucial contributions and will still be confronting any scientist working on CV prevention. Show less