Current opinion in lipidology最新文献

Purpose of review: Sphingolipids are structurally diverse membrane lipids localized in lipid bilayers. Sphingolipids are not only important structural components of cellular membranes, but they are also important regulators of cellular trafficking and signal transduction and are implicated in several diseases. Here, we review the latest insights into sphingolipids and their role in cardiac function and cardiometabolic disease.

Recent findings: The underlying mechanisms linking sphingolipids to cardiac dysfunction are still not fully clarified. Sphingolipids, and in particular ceramides, have emerged as important players in lipotoxicity, mediating inflammation, impaired insulin signalling and apoptosis. In addition, recent findings highlight the importance of glycosphingolipid homeostasis in cardiomyocyte membranes, where they are required to maintain β-adrenergic signalling and contractile capacity to preserve normal heart function. Thus, glycosphingolipid homeostasis in cardiac membranes characterizes a novel mechanism linking sphingolipids to cardiac disease.

Summary: Modulation of cardiac sphingolipids may represent a promising therapeutic approach. Sustained investigation of the link between sphingolipids and cardiomyocyte function is therefore needed and we hope that this review may inspire researchers to further elucidate the action of these lipids.

Purpose of review: Patients with heterozygous familial hypercholesterolemia (HeFH) are at increased risk for COVID-19 cardiovascular complications in the acute phase of the infection. Elevated levels of LDL-C and often lipoprotein(a) are present from birth and lead to endothelial dysfunction, which is aggravated by a direct viral attack of the endothelial cells and their exposure to the toxic levels of circulating proinflammatory and prothrombotic mediators during the hyperinflammatory reaction typical of COVID-19.

Recent findings: Evidence to date shows the benefit of lipid-lowering therapy in patients with COVID-19. In HeFH patients who are at much higher cardiovascular risk, the focus should, therefore, be on the effective lowering of LDL-C levels, the root cause of the greater cardiovascular vulnerability to COVID-19 infection in these patients. The ongoing use of statins and other lipid-lowering therapies should be encouraged during the ongoing COVID pandemic to mitigate the risk of cardiovascular complications from COVID-19, particularly in HeFH patients.

Summary: Epidemiologic registry data show that the incidence of myocardial infarction is increased in SARS-CoV-2-infected HeFH patients. There is a need to study whether the risk for acute cardiovascular events is increased in the long-term and if there are changes in lipid metabolism after SARS-CoV infection(s) in patients with HeFH.

Purpose of review: To describe the uses of vessel wall volume (VWV) and measurement of carotid plaque burden, as total plaque area (TPA) and total plaque volume (TPV), and to contrast them with measurement of carotid intima-media thickness (IMT) and coronary calcium (CAC).

Recent findings: Measurement of carotid plaque burden (CPB) is useful for risk stratification, research into the genetics and biology of atherosclerosis, for measuring effects of new therapies for atherosclerosis, and for treatment of high-risk patients with severe atherosclerosis. It is as predictive of risk as CAC, with important advantages. IMT is only a weak predictor of risk and changes so little over time that it is not useful for assessing effects of therapy.

Summary: Measurement of CPB and VWV are far superior to measurement of carotid IMT in many ways, and should replace it. Vessel wall volume can be measured in persons with no plaque as an alternative to IMT. There are important advantages of CPB over coronary calcium; CPB should be more widely used in vascular prevention.

Purpose of review: Despite indisputable role of LDL-C lowering, a considerable residual risk for atherosclerotic cardiovascular disease (ASCVD) persists. The precise mechanism(s) underlying this phenomenon remain unclear. Triglyceride-rich lipoproteins (TRL) appear to be one of the main mediators, based on the genetic and epidemiologic data. However, whether this is caused by direct effects of Triglycerides or other components of TRL remains uncertain. The cholesterol component of TRL remnants (Rem-C) has been proposed as a more pertinent mediator of the increased risk associated with high triglycerides.

Recent findings: Several long-term observational studies have shown a significant relationship between Rem-C and ASCVD events, compared with other triglyceride-related parameters. Recent trials have shown that lowering of triglyceride levels by various agents, including fibrates and omega-3 fatty acids, in statin-treated subjects, did not explain the reduction in ASCVD events. In a large clinical trial with pemafibrate, a highly selective PPAR-α agonist, in type 2 diabetes and elevated triglycerides, the reduction in triglycerides was accompanied by a significant increase in LDL-C and Apo-B levels, despite a reduction in Rem-C, and no effect on ASCVD events.

Summary: Elevated Rem-C as a risk determinant, with LDL-C at goal, requires additional studies in clinical trials. Standardization and accuracy of Rem-C assays (calculated versus direct method) is also needed.

Purpose of review: We discuss two recent controversial issues in the research field of fatty liver: the proposal to replace nonalcoholic fatty liver disease (NAFLD) with metabolically associated fatty liver disease (MAFLD) and the suggestion to extend to primary care the noninvasive testing for liver fibrosis that was developed for secondary care.

Recent findings: There is preliminary evidence that MAFLD-only patients are at greater risk of fibrosis than NAFLD-only patients. There are a large number of false positives associated with the downshift of noninvasive testing for liver fibrosis from secondary to primary care.

Summary: More studies are needed to compare the MAFLD and NAFLD operational definitions. Noninvasive testing of liver fibrosis also needs further evaluation before it can be used in primary care or in the general population.

Purpose of review: Inflammation is gaining attention as a target for prevention of atherosclerotic cardiovascular disease (ASCVD). The purpose of this review is to compare the evidence for inflammation with the evidence for low-density lipoprotein (LDL) cholesterol in ASCVD.

Recent findings: Evidence from human genetic studies and randomized controlled trials implicate the inflammatory pathway from the inflammasome through interleukin (IL)-1 to IL-6 as a cause of ASCVD. Higher levels of IL-6 may lead to proportionally increased risk of ASCVD, and randomized controlled trials of IL-6 inhibitors are underway. The causal evidence for LDL cholesterol in ASCVD is overwhelming and recent important findings instead revolve around development of improved LDL cholesterol lowering therapy through RNA and DNA based therapeutics. Even though some lipid-lowering therapies lower IL-6, the IL-6 inflammatory pathway and LDL cholesterol are two separate causes of ASCVD.

Summary: IL-6 mediated inflammation most likely causes ASCVD, in parallel with LDL cholesterol. However, fewer individuals in the general population are exposed to high IL-6 than high LDL cholesterol. For inflammation, future research should focus on improving efficacy and safety of anti-inflammatory therapy, and for LDL cholesterol, future research should focus on wider and more effective implementation of LDL cholesterol lowering therapy.

Purpose of review: Exosomes are lipid-bound particles that carry lipids, protein, and nucleic acid and affect cellular function. This review highlights the current knowledge on the crosstalk between exosomes and lipid metabolism and their impact on cardiometabolic disease.

Recent findings: Recent studies revealed that lipids and lipid metabolizing enzymes are important for exosome biogenesis and internalization and conversely how exosomes affect lipid metabolism, secretion, and degradation. The interplay between exosomes and lipid metabolism affects disease pathophysiology. More importantly, exosomes and lipids might function as biomarkers for diagnosis and prognosis or possibly therapies.

Summary: Recent advances in our understanding of exosomes and lipid metabolism have implications for our understanding of normal cellular and physiological functions as well as disease pathogenesis. Exosome and lipid metabolism have implications in novel diagnostic tests and treatments of cardiometabolic disease.

Purpose of review: Genetic lecithin:cholesterol acyltransferase (LCAT) deficiency is a rare, inherited, recessive disease, which manifests as two different syndromes: Familial LCAT deficiency (FLD) and Fish-eye disease (FED), characterized by low HDL-C and corneal opacity. FLD patients also develop anaemia and renal disease. There is currently no therapy for FLD, but novel therapeutics are at different stages of development. Here, we summarize the most recent advances and the opportunities for and barriers to the further development of such therapies.

Recent findings: Recent publications highlight the heterogeneous phenotype of FLD and the uncertainty over the natural history of disease and the factors contributing to disease progression. Therapies that restore LCAT function (protein and gene replacement therapies and LCAT activators) showed promising effects on markers of LCAT activity. Although they do not restore LCAT function, HDL mimetics may slow renal disease progression.

Summary: The further development of novel therapeutics requires the identification of efficacy endpoints, which include quantitative biomarkers of disease progression. Because of the heterogeneity of renal disease progression among FLD individuals, future treatments for FLD will have to be tailored based on the specific clinical characteristics of the patient. Extensive studies of the natural history and biomarkers of the disease will be required to achieve this goal.