The pleiotropic effects of high-density lipoproteins and apolipoprotein A-I

Host Proteins in Echinococcus multilocularis Metacestodes

Metacestodes of Echinococcus multilocularis are the causative agents of alveolar echinococcosis, a neglected, life-threatening, zoonotic disease. To study these metacestodes in vitro, a model system using a culture medium conditioned by rat hepatoma cells is available. A key question is how the parasite interacts with the host and, in particular, which host-derived compounds are taken up. In this study, we focus on the uptake of host-derived proteins. Studies with artificially labeled proteins suggest that this uptake may occur independently of protein size or charge. Closer investigation using proteomics draws, however, a different picture. Of 1170 host (i.e., rat or bovine) proteins as identified by LC-MS/MS-based proteomics present in the culture medium, only 225 are found in metacestode vesicle tissue or fluid. Moreover, their relative abundances differ. Serum albumin, the most abundant culture medium host protein, is only the third most abundant protein in vesicle fluid, where Alpha-2-HS-glycoprotein becomes the most abundant protein. In vesicle fluid obtained ex vivo from experimentally infected mice, the situation is again different, with histone isoforms as the most abundant proteins. This suggests that while maintaining their internal milieu constant, metacestodes may adjust the spectrum of host proteins taken up. Potential uptake mechanisms and functions are discussed.

Correlation Between Uric Acid/High Density Lipoprotein Cholesterol Ratio and Postoperative AKI in Patients with CABG

Objective

This study aims to investigate the association between preoperative serum uric acid to high-density lipoprotein cholesterol ratio (UHR) and the occurrence of postoperative acute kidney injury (AKI) in patients who underwent coronary artery bypass grafting (CABG).

Methods

A prospective observational study was conducted at Fujian Heart Medical Center between May 2022 and December 2023, recruiting patients scheduled for CABG. Participants were categorized into two groups based on AKI occurrence post-surgery. Univariate and multivariate logistic regression analyses were performed to identify predictor variables for AKI after CABG. A nomogram was constructed based on these predictors, and its calibration was evaluated using the receiver operating characteristic curve (ROC) and Hosmer-Lemeshow goodness of fit test. The diagnostic value of UHR in AKI after CABG was explored using the area under the curve (AUC).

Results

The study included 301 CABG patients, of whom 72 (23.92%) developed AKI. After adjusting for age, gender, body mass index, and extracorporeal circulation, binary logistic regression analysis revealed that a higher UHR value was an independent risk factor for developing AKI after CABG (OR=7.410, 95% CI: 3.829-14.855), P <0.05. The prediction nomogram demonstrated excellent discriminability, with an AUC of 0.87 and good calibration (Hosmer-Lemeshow test, P <0.05). Compared with other clinical indicators, ROC analysis indicated that UHR had the largest AUC (0.821), corresponding to 70.8% sensitivity and 79.0% specificity.

Conclusion

Higher UHR was associated with an increased risk of AKI after CABG and may serve as a prospective biomarker for predicting AKI.

Untargeted lipidomics reveals novel HDL metabotypes and lipid-clinical correlates

Plasma high-density lipoprotein (HDL), originally studied for its role in lipid transport, is now appreciated to have wide-ranging biological functions that become defective during disease. While >200 lipids have collectively been detected in HDL, published HDL lipidomic analyses in different diseases have commonly been targeted to prespecified subsets of lipids. Here, we report the results of untargeted lipidomic analysis of HDL isolated from 101 subjects referred for computed tomographic coronary imaging for whom multiple additional clinical and lipoprotein metadata were measured. Unsupervised clustering of the total HDL lipidome revealed that the subjects fell into one of two discrete groups, herein referred to as HDL "metabotypes." Patients in metabotype 1 were likelier to be female and tended to have a less atherogenic lipoprotein profile, higher HDL cholesterol efflux capacity (CEC), and lower-grade non-calcified burden on coronary imaging than metabotype 2 counterparts. Specific lipids were relatively enriched in metabotype 1 HDL. Linear modeling revealed that several of these lipids were positively associated with CEC, statin use, HDL size, and HDL particle number, and positively correlated with HDL apolipoprotein A-1, suggesting that they may be informative HDL biomarkers. Taken together, we posit a novel, clinically relevant categorization for HDL revealed by systems biology.

Intermittent Fasting Regulates Metabolic Homeostasis and Improves Cardiovascular Health

Obesity is a leading cause of morbidity and mortality globally. While the prevalence of obesity has been increasing, the incidence of its related complications including dyslipidemia and cardiovascular disease (CVD) has also been rising. Recent research has focused on modalities aimed at reducing obesity. Several modalities have been suggested including behavioral and dietary changes, medications, and bariatric surgery. These modalities differ in their effectiveness and invasiveness, with dietary changes gaining more interest due to their minimal risks compared to other modalities. Specifically, intermittent fasting (IF) has been gaining interest in the past decade. IF is characterized by cycles of alternating fasting and eating windows, with several different forms practiced. IF has been shown to reduce weight and alleviate obesity-related complications. Our review of clinical and experimental studies explores the effects of IF on the lipid profile, white adipose tissue (WAT) dynamics, and the gut microbiome. Notably, IF corrects dyslipidemia, reduces WAT accumulation, and decreases inflammation, which reduces CVD and obesity. This comprehensive analysis details the protective metabolic role of IF, advocating for its integration into public health practices.

High-density lipoprotein in diabetes: Structural and functional relevance

Low levels of high-density lipoprotein-cholesterol (HDL-C) is considered a major cardiovascular risk factor. However, recent studies have suggested a more U-shaped association between HDL-C and cardiovascular disease. It has been shown that the cardioprotective effect of HDL is related to the functions of HDL particles rather than their cholesterol content. HDL particles are highly heterogeneous and have multiple functions relevant to cardiometabolic conditions including cholesterol efflux capacity, anti-oxidative, anti-inflammatory, and vasoactive properties. There are quantitative and qualitative changes in HDL as well as functional abnormalities in both type 1 and type 2 diabetes. Non-enzymatic glycation, carbamylation, oxidative stress, and systemic inflammation can modify the HDL composition and therefore the functions, especially in situations of poor glycemic control. Studies of HDL proteomics and lipidomics have provided further insights into the structure-function relationship of HDL in diabetes. Interestingly, HDL also has a pleiotropic anti-diabetic effect, improving glycemic control through improvement in insulin sensitivity and β-cell function. Given the important role of HDL in cardiometabolic health, HDL-based therapeutics are being developed to enhance HDL functions rather than to increase HDL-C levels. Among these, recombinant HDL and small synthetic apolipoprotein A-I mimetic peptides may hold promise for preventing and treating diabetes and cardiovascular disease.

Closing the gaps in patient management of dyslipidemia: stepping into cardiovascular precision diagnostics with apolipoprotein profiling

In persons with dyslipidemia, a high residual risk of cardiovascular disease remains despite lipid lowering therapy. Current cardiovascular risk prediction mainly focuses on low-density lipoprotein cholesterol (LDL-c) levels, neglecting other contributing risk factors. Moreover, the efficacy of LDL-c lowering by statins resulting in reduced cardiovascular risk is only partially effective. Secondly, from a metrological viewpoint LDL-c falls short as a reliable measurand. Both direct and calculated LDL-c tests produce inaccurate test results at the low end under aggressive lipid lowering therapy. As LDL-c tests underperform both clinically and metrologically, there is an urging need for molecularly defined biomarkers. Over the years, apolipoproteins have emerged as promising biomarkers in the context of cardiovascular disease as they are the functional workhorses in lipid metabolism. Among these, apolipoprotein B (ApoB), present on all atherogenic lipoprotein particles, has demonstrated to clinically outperform LDL-c. Other apolipoproteins, such as Apo(a) - the characteristic apolipoprotein of the emerging risk factor lipoprotein(a) -, and ApoC-III - an inhibitor of triglyceride-rich lipoprotein clearance -, have attracted attention as well. To support personalized medicine, we need to move to molecularly defined risk markers, like the apolipoproteins. Molecularly defined diagnosis and molecularly targeted therapy require molecularly measured biomarkers. This review provides a summary of the scientific validity and (patho)physiological role of nine serum apolipoproteins, Apo(a), ApoB, ApoC-I, ApoC-II, ApoC-III, ApoE and its phenotypes, ApoA-I, ApoA-II, and ApoA-IV, in lipid metabolism, their association with cardiovascular disease, and their potential as cardiovascular risk markers when measured in a multiplex apolipoprotein panel.

Adipose tissue dysfunction serum markers are associated with high density lipoprotein size and glycation in the early stages of type 2 diabetes

BACKGROUND

High-density lipoproteins (HDLs) have antiatherogenic properties related to their chemical structure. Adipose tissue (AT) influences HDL reverse cholesterol transport and plasma HDL cholesterol levels. However, whether AT dysfunction affects HDL subpopulations and their glycation in early type 2 diabetes (T2D) is still unknown.

OBJECTIVE

To investigate the association of inflammation and AT dysfunction serum markers with the size and glycation of HDLs in normoglycemic, prediabetes, and T2D subjects.

METHODS

We assessed HDL particle size and advanced glycation end-product (AGE) content in HDLs isolated from normoglycemic (n = 17), prediabetes (n = 17), and recently T2D-diagnosed (n = 18) subjects. Insulin, adiponectin, and plasminogen activator inhibitor 1 (PAI-1) were determined using the Bio-Rad Multiplex Platform, and free fatty acids (FFAs) and high sensitivity C-reactive protein (hs-CRP) were determined by standard procedures. The AT insulin resistance (ATIR) index and ATIR/adiponectin and adiponectin/leptin ratios were calculated.

RESULTS

HDL was progressively smaller (nm) and enriched with AGE (mg-BSA-AGE/mg protein) according to the glucose categories: 8.49 and 7.5 in normoglycemic subjects, 8.44 and 12.4 in prediabetic subjects, and 8.32 and 14.3 in T2D subjects (P = 0.033 and P = 0.009 for size and AGE, respectively). In multivariable regression analysis, the ATIR/adiponectin ratio was inversely associated with HDL size (β = -0.257, P = 0.046), and the ATIR ratio was directly associated with HDL glycation (β = 0.387, P = 0.036). In contrast, adiponectin and the adiponectin/leptin ratio were not associated with alterations in HDL particles. Furthermore, HDL size was associated with resistin (β = -0.348, P = 0.007) and PAI-1 (β = -0.324, P = 0.004). HDL and AGE were related to insulin concentrations (β = 0.458, P = 0.015). Analyses were adjusted for age, sex, body mass index, triglycerides, and HDL-cholesterol.

CONCLUSION

HDL size was significantly associated with the ATIR/adiponectin ratio and inflammation, whereas glycation was more strongly related to the ATIR index. These findings have important implications for the management and prevention of cardiovascular disease in T2D patients.