ApoA-1 improves glucose tolerance by increasing glucose uptake into heart and skeletal muscle independently of AMPKα2

Associations of Serum Apolipoprotein A1 and High Density Lipoprotein Cholesterol With Glucose Level in Patients With Coronary Artery Disease

This study determined the associations of apolipoprotein A1 (ApoA1), high-density lipoprotein cholesterol (HDL-C), and HDL-C/ApoA1 ratio with fasting blood glucose (FBG) and evaluated the mediating effects of high-sensitivity C-reactive protein (hsCRP) and body mass index (BMI). A cross-sectional study with 4805 coronary artery disease (CAD) patients was performed. In multivariable analyses, higher ApoA1, HDL-C, and HDL-C/ApoA1 ratio were associated with significantly lower FBG level (Q [quartile] 4 vs Q1: 5.67 vs 5.87 mmol/L for ApoA1; 5.64 vs 5.98 mmol/L for HDL-C; 5.63 vs 6.01 mmol/L for HDL-C/ApoA1 ratio). Moreover, inverse associations of ApoA1, HDL-C, and HDL-C/ApoA1 ratio with abnormal FBG (AFBG) were found with odd ratios (95% confidence interval) of .83 (.70-.98), .60 (.50-.71), and .53 (.45-.64) in Q4 compared with Q1. Path analyses indicated that "ApoA1 (or HDL-C)-FBG" associations were mediated by hsCRP and "HDL-C-FBG" association was mediated by BMI. Our data suggested that higher ApoA1, HDL-C, and HDL-C/ApoA1 ratio were favorably associated with a lower FBG level in CAD patients and these associations might be mediated by hsCRP or BMI. Collectively, higher concentrations of ApoA1, HDL-C, and HDL-C/ApoA1 ratio might decrease the risk of AFBG.

The Pleiotropic Effects of Lipid-Modifying Interventions: Exploring Traditional and Emerging Hypolipidemic Therapies

Atherosclerotic cardiovascular disease poses a significant global health issue, with dyslipidemia standing out as a major risk factor. In recent decades, lipid-lowering therapies have evolved significantly, with statins emerging as the cornerstone treatment. These interventions play a crucial role in both primary and secondary prevention by effectively reducing cardiovascular risk through lipid profile enhancements. Beyond their primary lipid-lowering effects, extensive research indicates that these therapies exhibit pleiotropic actions, offering additional health benefits. These include anti-inflammatory properties, improvements in vascular health and glucose metabolism, and potential implications in cancer management. While statins and ezetimibe have been extensively studied, newer lipid-lowering agents also demonstrate similar pleiotropic effects, even in the absence of direct cardiovascular benefits. This narrative review explores the diverse pleiotropic properties of lipid-modifying therapies, emphasizing their non-lipid effects that contribute to reducing cardiovascular burden and exploring emerging benefits for non-cardiovascular conditions. Mechanistic insights into these actions are discussed alongside their potential therapeutic implications.

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.

Thapsigargin and Tunicamycin Block SARS-CoV-2 Entry into Host Cells via Differential Modulation of Unfolded Protein Response (UPR), AKT Signaling, and Apoptosis

BACKGROUND

SARS-Co-V2 infection can induce ER stress-associated activation of unfolded protein response (UPR) in host cells, which may contribute to the pathogenesis of COVID-19. To understand the complex interplay between SARS-Co-V2 infection and UPR signaling, we examined the effects of acute pre-existing ER stress on SARS-Co-V2 infectivity.

METHODS

Huh-7 cells were treated with Tunicamycin (TUN) and Thapsigargin (THA) prior to SARS-CoV-2pp transduction (48 h p.i.) to induce ER stress. Pseudo-typed particles (SARS-CoV-2pp) entry into host cells was measured by Bright GloTM luciferase assay. Cell viability was assessed by cell titer Glo® luminescent assay. The mRNA and protein expression was evaluated by RT-qPCR and Western Blot.

RESULTS

TUN (5 µg/mL) and THA (1 µM) efficiently inhibited the entry of SARS-CoV-2pp into host cells without any cytotoxic effect. TUN and THA's attenuation of virus entry was associated with differential modulation of ACE2 expression. Both TUN and THA significantly reduced the expression of stress-inducible ER chaperone GRP78/BiP in transduced cells. In contrast, the IRE1-XBP1s and PERK-eIF2α-ATF4-CHOP signaling pathways were downregulated with THA treatment, but not TUN in transduced cells. Insulin-mediated glucose uptake and phosphorylation of Ser307 IRS-1 and downstream p-AKT were enhanced with THA in transduced cells. Furthermore, TUN and THA differentially affected lipid metabolism and apoptotic signaling pathways.

CONCLUSIONS

These findings suggest that short-term pre-existing ER stress prior to virus infection induces a specific UPR response in host cells capable of counteracting stress-inducible elements signaling, thereby depriving SARS-Co-V2 of essential components for entry and replication. Pharmacological manipulation of ER stress in host cells might provide new therapeutic strategies to alleviate SARS-CoV-2 infection.

Exploring Possible Links: Thigh Muscle Mass, Apolipoproteins, and Glucose Metabolism in Peripheral Artery Disease-Insights from a Pilot Sub-Study following Endovascular Treatment

Peripheral artery disease (PAD) compromises walking and physical activity, which results in further loss of skeletal muscle. The cross-sectional area of the thigh muscle has been shown to be correlated with systemic skeletal muscle volume. In our previous pilot study, we observed an increase in thigh muscle mass following endovascular treatment (EVT) in patients with proximal vascular lesions affecting the aortoiliac and femoropopliteal arteries. Considering the potential interactions between skeletal muscle, lipid profile, and glucose metabolism, we aimed to investigate the relationship between thigh muscle mass and apolipoproteins as well as glucose metabolism in PAD patients undergoing EVT. This study is a prespecified sub-study conducted as part of a pilot study. We prospectively enrolled 22 symptomatic patients with peripheral artery disease (PAD) and above-the-knee lesions, specifically involving the blood vessels supplying the thigh muscle. The mid-thigh muscle area was measured with computed tomography before and 6 months after undergoing EVT. Concurrently, we measured levels of apolipoproteins A1 (Apo A1) and B (Apo B), fasting blood glucose, 2 h post-load blood glucose (using a 75 g oral glucose tolerance test), and glycated hemoglobin A1c (HbA1c). Changes in thigh muscle area (delta muscle area: 2.5 ± 8.1 cm2) did not show significant correlations with changes in Apo A1, Apo B, fasting glucose, 2 h post-oral glucose tolerance test blood glucose, HbA1c, or Rutherford classification. However, among patients who experienced an increase in thigh muscle area following EVT (delta muscle area: 8.41 ± 5.93 cm2), there was a significant increase in Apo A1 (pre: 121.8 ± 15.1 mg/dL, 6 months: 136.5 ± 19.5 mg/dL, p < 0.001), while Apo B remained unchanged (pre: 76.4 ± 19.2 mg/dL, 6 months: 80.5 ± 4.9 mg/dL). Additionally, post-oral glucose tolerance test 2 h blood glucose levels showed a decrease (pre: 189.7 ± 67.5 mg/dL, 6 months: 170.6 ± 69.7 mg/dL, p = 0.075). Patients who exhibited an increase in thigh muscle area demonstrated more favorable metabolic changes compared to those with a decrease in thigh muscle area (delta muscle area: -4.67 ± 2.41 cm2). This pilot sub-study provides insights into the effects of EVT on thigh muscle, apolipoproteins, and glucose metabolism in patients with PAD and above-the-knee lesions. Further studies are warranted to validate these findings and establish their clinical significance. The trial was registered on the University Hospital Medical Information Network Clinical Trials Registry (UMIN000047534).

Antioxidant and Anti-Inflammatory Functions of High-Density Lipoprotein in Type 1 and Type 2 Diabetes

(1) Background: high-density lipoproteins (HDLs) exhibit antioxidant and anti-inflammatory properties that play an important role in preventing the development of atherosclerotic lesions and possibly also diabetes. In turn, both type 1 diabetes (T1D) and type 2 diabetes (T2D) are susceptible to having deleterious effects on these HDL functions. The objectives of the present review are to expound upon the antioxidant and anti-inflammatory functions of HDLs in both diabetes in the setting of atherosclerotic cardiovascular diseases and discuss the contributions of these HDL functions to the onset of diabetes. (2) Methods: this narrative review is based on the literature available from the PubMed database. (3) Results: several antioxidant functions of HDLs, such as paraoxonase-1 activity, are compromised in T2D, thereby facilitating the pro-atherogenic effects of oxidized low-density lipoproteins. In addition, HDLs exhibit diminished ability to inhibit pro-inflammatory pathways in the vessels of individuals with T2D. Although the literature is less extensive, recent evidence suggests defective antiatherogenic properties of HDL particles in T1D. Lastly, substantial evidence indicates that HDLs play a role in the onset of diabetes by modulating glucose metabolism. (4) Conclusions and perspectives: impaired HDL antioxidant and anti-inflammatory functions present intriguing targets for mitigating cardiovascular risk in individuals with diabetes. Further investigations are needed to clarify the influence of glycaemic control and nephropathy on HDL functionality in patients with T1D. Furthermore, exploring the effects on HDL functionality of novel antidiabetic drugs used in the management of T2D may provide intriguing insights for future research.

Associations of apolipoproteinA1, high density lipoprotein cholesterol with hemoglobin glycation index and triglyceride-glucose index in Chinese adults with coronary artery disease

AIMS

Scarce data explored the associations of apolipoproteins with hemoglobin glycation index (HGI) and triglyceride-glucose (TyG) index. This study determined associations of serum apolipoproteinA1 (ApoA1) and high density lipoprotein cholesterol (HDL-C) with HGI and TyG index in coronary artery disease (CAD) patients.

METHODS

A total of 10,803 CAD patients were included in this cross-sectional pilot study. Serum concentrations of ApoA1 and HDL-C were measured. Analyses of covariance were used to compare the mean differences in glucose metabolism indices (e.g., HGI, TyG index, hemoglobin glycation [HbA1c], fasting blood glucose [FBG]) among the quartiles of ApoA1, HDL-C and HDL-C/ApoA1 ratio.

RESULTS

In multivariate analysis, higher ApoA1, HDL-C and HDL-C/ApoA1 ratio were associated with significantly lower HGI (Quartile [Q]4 vs. Q1: -0.032 % vs. 0.017 % for ApoA1; -0.072 % vs. 0.079 % for HDL-C; -0.083 % vs. 0.085 % for HDL-C/ApoA1 ratio). Intermediate ApoA1 level was inversely associated with TyG index (Q2 vs. Q1: 296.278 vs. 306.794). The mean TyG index were significantly decreased with increased HDL-C and HDL-C/ApoA1 ratio (Q4 vs. Q1: 298.584 vs. 309.221 for HDL-C; 300.405 vs. 315.218 for HDL-C/ApoA1 ratio). Moreover, the inverse associations of ApoA1, HDL-C and HDL-C/ApoA1 ratio with HbA1c and FBG also were observed. In path analysis, the associations of HDL-C and HDL-C/ApoA1 ratio with TyG index were mediated by obesity.

CONCLUSION

This study provided further support for the hypoglycemic effects of ApoA1 and HDL-C in patients with CAD. Replication of these findings is warranted in further longitudinal studies in different populations.

Utility of apolipoprotein ratio in predicting metabolic risk and microvascular complications in Indian children and young adults with type 1 diabetes mellitus

OBJECTIVES

To assess the relationship of apolipoproteins with glycemic control and insulin resistance (IR) in Indian children and youth with type-1 diabetes (T1D) and to assess its utility in predicting metabolic risk (MR) and microvascular complications in these subjects.

METHODS

This cross-sectional study included 152 participants aged 6-23 years with T1D. Demographic, anthropometric, clinical, biochemical and body composition data were obtained using standard protocols. IR was calculated using estimated glucose disposal rate (eGDR) and metabolic syndrome (MS) was diagnosed using the international diabetes federation consensus definition 2017.

RESULTS

Apolipoprotein ratio in subjects with T1D had negative and positive correlation with eGDR and HbA_1c respectively. Positive correlation of Apolipoproten B and apolipoprotein ratio with urinary albumin creatinine ratio is noted. The ratio had area under curve of 0.766 and 0.737 to predict MR and microvascular complications respectively. The ratio cut-off of 0.536 yielded 77.1 % sensitivity and 61 % specificity to predict MR. On adding the apolipoprotein ratio as a predictor to the regression model developed to predict MR, the R² and accuracy improved.

CONCLUSIONS

The apolipoprotein ratio had significant correlation with IR, microalbuminuria and glycaemic control. The ratio also predicts risk of development of microvascular complications and maybe used to predict MR in subjects with T1D.

Identification of Key Genes and Biological Pathways Associated with Skeletal Muscle Maturation and Hypertrophy in Bos taurus, Ovis aries, and Sus scrofa

The aim of the current study was to identify the major genes and pathways involved in the process of hypertrophy and skeletal muscle maturation that is common for Bos taurus, Ovis aries, and Sus scrofa species. Gene expression profiles related to Bos taurus, Ovis aries, and Sus scrofa muscle, with accession numbers GSE44030, GSE23563, and GSE38518, respectively, were downloaded from the GEO database. Differentially expressed genes (DEGs) were screened out using the Limma package of R software. Genes with Fold Change > 2 and an adjusted p-value < 0.05 were identified as significantly different between two treatments in each species. Subsequently, gene ontology and pathway enrichment analyses were performed. Moreover, hub genes were detected by creating a protein−protein interaction network (PPI). The results of the analysis in Bos taurus showed that in the period of 280 dpc−3-months old, a total of 1839 genes showed a significant difference. In Ovis aries, however, during the period of 135dpc−2-months old, a total of 486 genes were significantly different. Additionally, in the 91 dpc−adult period, a total of 2949 genes were significantly different in Sus scrofa. The results of the KEGG pathway enrichment analysis and GO function annotation in each species separately revealed that in Bos taurus, DEGs were mainly enriched through skeletal muscle fiber development and skeletal muscle contraction, and the positive regulation of fibroblast proliferation, positive regulation of skeletal muscle fiber development, PPAR signaling pathway, and HIF-1 signaling pathway. In Ovis aries, DEGs were mainly enriched through regulating cell growth, skeletal muscle fiber development, the positive regulation of fibroblast proliferation, skeletal muscle cell differentiation, and the PI3K-Akt signaling, HIF-1 signaling, and Rap1 signaling pathways. In Sus scrofa, DEGs were mainly enriched through regulating striated muscle tissue development, the negative regulation of fibroblast proliferation and myoblast differentiation, and the HIF-1 signaling, AMPK signaling, and PI3K-Akt signaling pathways. Using a Venn diagram, 36 common DEGs were identified between Bos taurus, Ovis aries, and Sus scrofa. A biological pathways analysis of 36 common DEGs in Bos taurus, Ovis aries, and Sus scrofa allowed for the identification of common pathways/biological processes, such as myoblast differentiation, the regulation of muscle cell differentiation, and positive regulation of skeletal muscle fiber development, that orchestrated the development and maturation of skeletal muscle. As a result, hub genes were identified, including PPARGC1A, MYOD1, EPAS1, IGF2, CXCR4, and APOA1, in all examined species. This study provided a better understanding of the relationships between genes and their biological pathways in the skeletal muscle maturation process.

Relationship between the ApoB/ApoA-I ratio trajectory and risk of type 2 diabetes in China: a retrospective cohort study

PURPOSE

Little research has investigated the correlation of changes in long-term apolipoprotein B/apolipoprotein A-I (ApoB/ApoA-I) ratio with risk of new-onset type 2 diabetes (T2D) among ordinary people. Therefore, the research took long-term ApoB/ApoA-I ratio trajectories as independent variables for exploring their association with the risk of newly diagnosed T2D.

METHODS

Altogether 5362 non-diabetic participants with a median age of 49 were enrolled in the cohort study. Their ApoB/ApoA-I ratio trajectories from 2016 to 2019 were analyzed and grouped using group-based trajectory modeling. The Kaplan-Meier approach was employed for calculating the newly diagnosed T2D-related incidence with different ApoB/ApoA-I ratio trajectories. A log-rank test was conducted for testing the presence of statistical difference in new-onset T2D incidence among the different ApoB/ApoA-I ratio trajectory groups. A multivariate Cox proportional hazards regression model was adopted for analyzing how ApoB/ApoA-I ratio trajectory changes affected new-onset T2D.

RESULTS

From 2016 to 2019, 199 patients developed T2D (3% in 3 years). The incidence of T2D was 2.0%, 3.28%, 5.86%, and 6.92% for low, middle, upper, and high ApoB/ApoA-I ratio trajectories, respectively. Following adjustment of underlying confounding factors, in contrast to low ApoB/ApoA-I ratio trajectory, new-onset T2D risk ratios and hazard ratio (HR) (95% confidence intervals [CI]) for the middle lower ApoB/ApoA-I ratio trajectory, and upper middle and high ApoB/ApoA-I ratio trajectories were [HR (95% CI)] 1.35(0.88-2.08), 1.98(1.27-3.09) and 2.42(1.35-4.34), respectively, indicating high and statistically significant risks of T2D.

CONCLUSION

Variations of the ApoB/ApoA-I ratio trajectory exerted independent effects on the 3-year incidence of T2D. Long-term monitoring on the ApoB/ApoA-I ratio locus may help improve the identification on patients with T2D.

Serum apolipoprotein A1 rather than apolipoprotein B is associated with hypertension prevalence in Chinese people with coronary artery disease

OBJECTIVE

Studies on the association of apolipoprotein A1 (ApoA1) and apolipoprotein B (ApoB) with hypertension (HTN) prevalence in patients with coronary artery disease (CAD) are limited. This cross-sectional study aimed to investigate this association in Chinese people in Wuhan, China.

METHODS

Serum ApoA1 and ApoB levels were measured by immunoturbidimetry assay. Logistic regression analysis was used to estimate the associations of ApoA1 and ApoB level and ApoB/A1 ratio with HTN prevalence.

RESULTS

We included 5192 individuals (3060 men, mean age 61 years; 4412 HTN cases) in this study. After adjusting for covariates, serum ApoA1 but not ApoB level or ApoB/A1 ratio was inversely associated with HTN prevalence. HTN prevalence was reduced with the fifth versus first quintile of ApoA1 level [odds ratio = 0.78 (95% confidence interval 0.62-0.98)]. In stratified analyses based on sex, the probability of HTN with the fifth versus first ApoA1 level was 0.71 (0.53-0.96) for men. The probability of HTN with the fifth versus first quintile of ApoB/A1 ratio was 1.54 (1.11-2.13) after adjustment. With quintiles 2-5 versus of ApoB level, the probability of HTN did not differ in both men and women. On path analyses, the association of ApoA1 level and ApoB/A1 ratio with HTN was mediated by BMI (β coefficients: -0.179 to 0.133).

CONCLUSION

In general, high serum ApoA1 level may be associated with a reduced probability of HTN prevalence in patients with CAD in China, and this association may be mediated by BMI.

Cross-sectional and longitudinal associations of apolipoprotein A1 and B with glycosylated hemoglobin in Chinese adults

Apolipoproteins exert a key role on glucose metabolism; however, scarce data have examined the relationship between apolipoproteins and glycated haemoglobin (HbA1c) in Chinese adults. This study determined the cross-sectional and longitudinal associations of serum Apolipoprotein A1 (ApoA1), Apolipoprotein B (ApoB) and the ApoB/A1 ratio with HbA1c in Chinese adults. A total of 1448 subjects (584 men and 864 women) aged 54.8 years were included in a baseline survey, and the concentrations of Apo and HbA1c were measured. A total of 826 participants were followed up approximately once after 3.94 ± 0.62 years. In cross-sectional analysis, serum ApoA1 was inversely associated with HbA1c, while ApoB and the ApoB/A1 ratio were positively associated with HbA1c. After further adjusting for the potential covariates, a higher ApoA1 was associated with lower HbA1c (Quartile 4 [Q4] vs. Q1 = 5.673% vs. 5.796%, P-trend = 0.014). In contrast, positive association of ApoB concentration and the ApoB/A1 ratio with HbA1c level were showed (Q4 vs. Q1 = 5.805% vs. 5.589% for ApoB; Q4 vs. Q1 = 5.841% vs. 5.582% for ApoB/A1 ratio). The longitudinal results showed no significant associations of ApoA1, ApoB levels and the ApoB/A1 ratio with HbA1c changes (all P-trends > 0.05). Path analysis suggested that body mass index did not have mediating effect on Apo-HbA1c association. Our findings revealed that higher ApoA1, lower ApoB concentrations and the ApoB/A1 ratio were associated with lower HbA1c level in Chinese adults.

Comprehensive Transcriptome Profiling of NAFLD- and NASH-Induced Skeletal Muscle Dysfunction

Nonalcoholic fatty liver disease (NAFLD), characterized by extensive triglyceride accumulation in hepatocytes, may progress to nonalcoholic steatohepatitis (NASH) with liver fibrosis and inflammation and increase the risk of cirrhosis, cancer, and death. It has been reported that physical exercise is effective in ameliorating NAFLD and NASH, while skeletal muscle dysfunctions, including lipid deposition and weakness, are accompanied with NAFLD and NASH. However, the molecular characteristics and alterations in skeletal muscle in the progress of NAFLD and NASH remain unclear. In the present study, we provide a comprehensive analysis on the similarity and heterogeneity of quadriceps muscle in NAFLD and NASH mice models by RNA sequencing. Importantly, Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway functional enrichment analysis revealed that NAFLD and NASH led to impaired glucose and lipid metabolism and deteriorated functionality in skeletal muscle. Besides this, we identified that myokines possibly mediate the crosstalk between muscles and other metabolic organs in pathological conditions. Overall, our analysis revealed a comprehensive understanding of the molecular signature of skeletal muscles in NAFLD and NASH, thus providing a basis for physical exercise as an intervention against liver diseases.

Plasma Apolipoproteins A1/B and OxLDL Levels in Patients with Covid-19 As Possible Markers of the Disease

The COVID-19 infection is associated with dyslipidemia and cardiovascular complications. The aim of the study was to determine the content of ApoA1, ApoB, and oxidized low-density lipoproteins (oxLDL) in the plasma of patients (n = 81) with COVID-19, diabetes, and cardiovascular disease (CVD). ApoA1, ApoB, and oxLDL were determined using enzyme-linked immunosorbent assay kits (Elabscience, United States). The measurements were performed at an optical wavelength of 450 nm. It was shown that the level of ApoA1 in the blood of patients with type 2 diabetes and especially with COVID-19 was significantly lower than in the blood of healthy people. Blood ApoA1 levels did not show a further decrease in patients with both COVID-19 and diabetes or CVD compared to patients with COVID-19 without concomitant diseases. It was found that the level of ApoB in the blood of patients with diabetes and, especially, with COVID-19 is significantly higher than in the blood of healthy people. Blood levels of ApoB and oxLDL are higher in patients with both COVID-19 and diabetes or CVD compared to patients with COVID-19 without comorbidities. Thus, levels of ApoA1, ApoB, and oxLDL may be promising markers of COVID-19.

HDL and type 2 diabetes: the chicken or the egg?

HDL is a complex macromolecular cluster of various components, such as apolipoproteins, enzymes and lipids. Quality evidence from clinical and epidemiological studies led to the principle that HDL-cholesterol (HDL-C) levels are inversely correlated with the risk of CHD. Nevertheless, the failure of many cholesteryl ester transfer protein inhibitors to protect against CVD casts doubts on this principle and highlights the fact that HDL functionality, as dictated by its proteome and lipidome, also plays an important role in protecting against metabolic disorders. Recent data indicate that HDL-C levels and HDL particle functionality are correlated with the pathogenesis and prognosis of type 2 diabetes mellitus, a major risk factor for CVD. Hyperglycaemia leads to reduced HDL-C levels and deteriorated HDL functionality, via various alterations in HDL particles' proteome and lipidome. In turn, reduced HDL-C levels and impaired HDL functionality impact the performance of key organs related to glucose homeostasis, such as pancreas and skeletal muscles. Interestingly, different structural alterations in HDL correlate with distinct metabolic abnormalities, as indicated by recent data evaluating the role of apolipoprotein A1 and lecithin-cholesterol acyltransferase deficiency in glucose homeostasis. While it is becoming evident that not all HDL disturbances are causatively associated with the development and progression of type 2 diabetes, a bidirectional correlation between these two conditions exists, leading to a perpetual self-feeding cycle.

High Density Lipoproteins and Diabetes

Epidemiological studies have established that a high plasma high density lipoprotein cholesterol (HDL-C) level is associated with reduced cardiovascular risk. However, recent randomised clinical trials of interventions that increase HDL-C levels have failed to establish a causal basis for this relationship. This has led to a shift in HDL research efforts towards developing strategies that improve the cardioprotective functions of HDLs, rather than simply increasing HDL-C levels. These efforts are also leading to the discovery of novel HDL functions that are unrelated to cardiovascular disease. One of the most recently identified functions of HDLs is their potent antidiabetic properties. The antidiabetic functions of HDLs, and recent key advances in this area are the subject of this review. Given that all forms of diabetes are increasing at an alarming rate globally, there is a clear unmet need to identify and develop new approaches that will complement existing therapies and reduce disease progression as well as reverse established disease. Exploration of a potential role for HDLs and their constituent lipids and apolipoproteins in this area is clearly warranted. This review highlights focus areas that have yet to be investigated and potential strategies for exploiting the antidiabetic functions of HDLs.

Association of apolipoproteins A1 and B with type 2 diabetes and fasting blood glucose: a cross-sectional study

BACKGROUND

Apolipoprotein (Apo) may be associated with type 2 diabetes (T2D), however, little is known whether or not serum apolipoproteins are correlated with fasting blood glucose (FBG) and the prevalence of T2D in Chinese populations. In this study, we examined the association of serum ApoA1, ApoB, and the ratio of ApoB/ApoA1 (ApoB/A1 ratio) with T2D and FBG level, and compared apolipoprotein indicators in predicting T2D in Chinese adults.

METHODS

A total of 1027 subjects were enrolled in this cross-sectional study. The association of ApoA1, ApoB, and ApoB/A1 ratio with T2D prevalence was determined using logistic regression models. Multivariate-analysis of covariance (ANCOVA) was performed for comparisons of the mean difference in FBG level.

RESULTS

We found that ApoB and ApoB/A1 ratio were positively associated with T2D prevalence and FBG, while inverse association was noted between ApoA1 and T2D prevalence as well as FBG. Stratified analyses for sex, age, body mass index (BMI), smoking, and alcohol consumption showed no significant difference for the association of ApoA1, ApoB, and ApoB/A1 ratio with the prevalence of T2D among subgroups (all p-interactions> 0.05). Nonetheless, ApoA1 poorly performed in predicting T2D as it provided an AUC value of 0.310 that was significantly lower than those observed for ApoB (AUC value: 0.631) and ApoB/A1 ratio (AUC value: 0.685). Finally, path analyses indicated that the association between ApoB and T2D was mediated by BMI.

CONCLUSIONS

This study reveals the association of serum ApoA1, ApoB, and ApoB/A1 ratio with T2D and FBG in Chinese adults, suggesting that ApoB and ApoB/A1 ratio may be early indicators for predicting T2D. Prospective investigation in large cohort is needed.

APOA1: a Protein with Multiple Therapeutic Functions

PURPOSE OF THE REVIEW

Apolipoprotein (APO) A1, the main apolipoprotein of plasma high-density lipoproteins (HDLs), has several well documented cardioprotective functions. A number of additional potentially beneficial functions of APOA1 have recently been identified. This review is concerned with the therapeutic potential of all of these functions in multiple disease states.

RECENT FINDINGS

Knowledge of the beneficial functions of APOA1 in atherosclerosis, thrombosis, diabetes, cancer, and neurological disorders is increasing exponentially. These insights have led to the development of clinically relevant peptides and APOA1-containing, synthetic reconstituted HDL (rHDL) preparations that mimic the functions of full-length APOA1. APOA1 is a multifunctional apolipoprotein that has therapeutic potential in several diseases. Translation of this knowledge into the clinic is likely to be dependent on the efficacy and bioavailability of small peptides and synthetic rHDL preparations that are currently under investigation, or in development.