Low levels of ApoA1 improve risk prediction of type 2 diabetes mellitus

Cholesterol transport and beyond: Illuminating the versatile functions of HDL apolipoproteins through structural insights and functional implications

High-density lipoproteins (HDLs) play a vital role in lipid metabolism and cardiovascular health, as they are intricately involved in cholesterol transport and inflammation modulation. The proteome of HDL particles is indeed complex and distinct from other components in the bloodstream. Proteomics studies have identified nearly 285 different proteins associated with HDL; however, this review focuses more on the 15 or so traditionally named "apo" lipoproteins. Important lipid metabolizing enzymes closely working with the apolipoproteins are also discussed. Apolipoproteins stand out for their integral role in HDL stability, structure, function, and metabolism. The unique structure and functions of each apolipoprotein influence important processes such as inflammation regulation and lipid metabolism. These interactions also shape the stability and performance of HDL particles. HDLs apolipoproteins have multifaceted roles beyond cardiovascular diseases (CVDs) and are involved in various physiological processes and disease states. Therefore, a detailed exploration of these apolipoproteins can offer valuable insights into potential diagnostic markers and therapeutic targets. This comprehensive review article aims to provide an in-depth understanding of HDL apolipoproteins, highlighting their distinct structures, functions, and contributions to various physiological processes. Exploiting this knowledge holds great potential for improving HDL function, enhancing cholesterol efflux, and modulating inflammatory processes, ultimately benefiting individuals by limiting the risks associated with CVDs and other inflammation-based pathologies. Understanding the nature of all 15 apolipoproteins expands our knowledge of HDL metabolism, sheds light on their pathological implications, and paves the way for advancements in the diagnosis, prevention, and treatment of lipid and inflammatory-related disorders.

The neutrophil-to-apolipoprotein A1 ratio is associated with adverse outcomes in patients with acute decompensated heart failure at different glucose metabolic states: a retrospective cohort study

BACKGROUND

The present study was performed to assess the association between the neutrophil-to-apolipoprotein A1 ratio (NAR) and outcomes in patients with acute decompensated heart failure (ADHF) at different glucose metabolism states.

METHODS

We recruited 1233 patients with ADHF who were admitted to Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University from December 2014 to October 2019. The endpoints were defined as composites of cardiovascular death, nonfatal myocardial infarction, nonfatal ischemic stroke and exacerbation of chronic heart failure. The restricted cubic spline was used to determine the best cutoff of NAR, and patients were divided into low and high NAR groups. Kaplan-Meier plots and multivariable Cox proportional hazard models were used to investigate the association between NAR and the risk of adverse outcomes.

RESULTS

During the five-year follow-up period, the composite outcome occurred in 692 participants (56.1%). After adjusting for potential confounding factors, a higher NAR was associated with a higher incidence of composite outcomes in the total cohort (Model 1: HR = 1.42, 95% CI = 1.22-1.65, P<0.001; Model 2: HR = 1.29, 95% CI = 1.10-1.51, P = 0.002; Model 3: HR = 1.20, 95% CI = 1.01-1.42, P = 0.036). At different glucose metabolic states, a high NAR was associated with a high risk of composite outcomes in patients with diabetes mellitus (DM) (Model 1: HR = 1.54, 95% CI = 1.25-1.90, P<0.001; Model 2: HR = 1.40, 95% CI = 1.13-1.74, P = 0.002; Model 3: HR = 1.31, 95% CI = 1.04-1.66, P = 0.022), and the above association was not found in patients with prediabetes mellitus (Pre-DM) or normal glucose regulation (NGR) (both P>0.05).

CONCLUSIONS

The NAR has predictive value for adverse outcomes of ADHF with DM, which implies that the NAR could be a potential indicator for the management of ADHF.

How is Obstructive Sleep Apnea Associated with High Blood Pressure and Diabetes Mellitus Type 2? Clues from a Two-Step Mendelian Randomized Study

Background

Obstructive sleep apnea (OSA), high blood pressure (HBP), and type 2 diabetes mellitus (T2DM) have a close clinical relationship, but whether and how OSA affects HBP and T2DM is unclear.

Study Design and Methods

Two-step, two-sample Mendelian randomization techniques were applied using single-nucleotide polymorphisms as genetic instruments for exposure and mediators, thus minimizing bias due to confounding factors and reverse causality. The total effect of OSA on HBP and T2DM was categorized into direct and mediating effects based on the mediating factors.

Results

Two-sample MR analysis showed that OSA increased the risk of HBP (odds ratio [OR] = 1.010, 95% confidence interval [CI], 1.002-1.018; P = 0.0121) and T2DM (OR = 1.140, 95% CI, 1.059-1.228; P = 0.0005). In the process of OSA caused by HBP, sex hormone-binding globulin (SHBG) (female, 4.47% mediation; male, 2.76% mediation), total testosterone (TT) (male, 3.72% mediation), bioavailable testosterone (BioT) (female, 7.74% mediation), high-density lipoprotein cholesterol (HDL-C) (3.25% mediation), and apolipoprotein A1 (ApoA1) (1.31% mediation) were individual contributors. SHBG (female, 4.10% mediation; male, 1.58% mediation), TT (male, 3.69% mediation), BioT (female, 2.58% mediation), HDL-C (3.32% mediation), ApoA1 (2.14% mediation), and omega-6 fatty acids (2.33% mediation) may have mediating roles to varying degrees in the process of OSA caused by T2DM.

Interpretation

This MR study showed that OSA is a risk factor for HBP and T2DM, and the evaluation of mediators may help further reveal the specific mechanism by which OSA causes HBP and T2DM.

Waste Clearance in the Brain and Neuroinflammation: A Novel Perspective on Biomarker and Drug Target Discovery in Alzheimer's Disease

Alzheimer’s disease (AD) is a multifactorial disease with a heterogeneous etiology. The pathology of Alzheimer’s disease is characterized by amyloid-beta and hyperphosphorylated tau, which are necessary for disease progression. Many clinical trials on disease-modifying drugs for AD have failed to indicate their clinical benefits. Recent advances in fundamental research have indicated that neuroinflammation plays an important pathological role in AD. Damage- and pathogen-associated molecular patterns in the brain induce neuroinflammation and inflammasome activation, causing caspase-1-dependent glial and neuronal cell death. These waste products in the brain are eliminated by the glymphatic system via perivascular spaces, the blood-brain barrier, and the blood–cerebrospinal fluid barrier. Age-related vascular dysfunction is associated with an impairment of clearance and barrier functions, leading to neuroinflammation. The proteins involved in waste clearance in the brain and peripheral circulation may be potential biomarkers and drug targets in the early stages of cognitive impairment. This short review focuses on waste clearance dysfunction in AD pathobiology and discusses the improvement of waste clearance as an early intervention in prodromal AD and preclinical stages of dementia.

Severe types of fetopathy are associated with changes in the serological proteome of diabetic mothers

ABSTRACT

Pregestational or gestational diabetes are the main risk factors for diabetic fetopathy. There are no generalized signs of fetopathy before the late gestational age due to insufficient sensitivity of currently employed instrumental methods. In this cross-sectional observational study, we investigated several types of severe diabetic fetopathy (cardiomyopathy, central nervous system defects, and hepatomegaly) established in type 2 diabetic mothers during 30 to 35 gestational weeks and confirmed upon delivery. We examined peripheral blood plasma and determined a small proportion of proteins strongly associated with a specific type of fetopathy or anatomical malfunction. Most of the examined markers participate in critical processes at different stages of embryogenesis and regulate various phases of morphogenesis. Alterations in CDCL5 had a significant impact on mRNA splicing and DNA repair. Patients with central nervous system defects were characterized by the greatest depletion (ca. 7% of the basal level) of DFP3, a neurotrophic factor needed for the proper specialization of oligodendrocytes. Dysregulation of noncanonical wingless-related integration site signaling pathway (Wnt) signaling guided by pigment epithelium-derived factor (PEDF) and disheveled-associated activator of morphogenesis 2 (DAAM2) was also profound. In addition, deficiency in retinoic acid and thyroxine transport was exhibited by the dramatic increase of transthyretin (TTHY). The molecular interplay between the identified serological markers leads to pathologies in fetal development on the background of a diabetic condition. These warning serological markers can be quantitatively examined, and their profile may reflect different severe types of diabetic fetopathy, producing a beneficial effect on the current standard care for pregnant women and infants.

Spectrum of Apolipoprotein AI and Apolipoprotein AII Proteoforms and Their Associations With Indices of Cardiometabolic Health: The CARDIA Study

Background

ApoAI (apolipoproteins AI) and apoAII (apolipoprotein AII) are structural and functional proteins of high‐density lipoproteins (HDL) which undergo post‐translational modifications at specific residues, creating distinct proteoforms. While specific post‐translational modifications have been reported to alter apolipoprotein function, the full spectrum of apoAI and apoAII proteoforms and their associations with cardiometabolic phenotype remains unknown. Herein, we comprehensively characterize apoAI and apoAII proteoforms detectable in serum and their post‐translational modifications and quantify their associations with cardiometabolic health indices.

Methods and Results

Using top‐down proteomics (mass‐spectrometric analysis of intact proteins), we analyzed paired serum samples from 150 CARDIA (Coronary Artery Risk Development in Young Adults) study participants from year 20 and 25 exams. Measuring 15 apoAI and 9 apoAII proteoforms, 6 of which carried novel post‐translational modifications, we quantified associations between percent proteoform abundance and key cardiometabolic indices. Canonical (unmodified) apoAI had inverse associations with HDL cholesterol and HDL‐cholesterol efflux, and positive associations with obesity indices (body mass index, waist circumference), and triglycerides, whereas glycated apoAI showed positive associations with serum glucose and diabetes mellitus. Fatty‐acid‒modified ApoAI proteoforms had positive associations with HDL cholesterol and efflux, and inverse associations with obesity indices and triglycerides. Truncated and dimerized proteoforms of apoAII were associated with HDL cholesterol (positively) and obesity indices (inversely). Several proteoforms had no significant associations with phenotype.

Conclusions

Associations between apoAI and AII and cardiometabolic indices are proteoform‐specific. These results provide “proof‐of‐concept” that precise chemical characterization of human apolipoproteins will yield improved insights into the complex pathways through which proteins signify and mediate health and disease.

Heterogeneity of Lipid and Protein Cartilage Profiles Associated with Human Osteoarthritis with or without Type 2 Diabetes Mellitus

Osteoarthritis (OA) is a multifactorial pathology and comprises a wide range of distinct phenotypes. In this context, the characterization of the different molecular profiles associated with each phenotype can improve the classification of OA. In particular, OA can coexist with type 2 diabetes mellitus (T2DM). This study investigates lipidomic and proteomic differences between human OA/T2DM- and OA/T2DM+ cartilage through a multimodal mass spectrometry approach. Human cartilage samples were obtained after total knee replacement from OA/T2DM- and OA/T2DM+ patients. Label-free proteomics was employed to study differences in protein abundance and matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) for spatially resolved-lipid analysis. Label-free proteomic analysis showed differences between OA/T2DM- and OA/T2DM+ phenotypes in several metabolic pathways such as lipid regulation. Interestingly, phospholipase A2 protein was found increased within the OA/T2DM+ cohort. In addition, MALDI-MSI experiments revealed that phosphatidylcholine and sphingomyelin species were characteristic of the OA/T2DM- group, whereas lysolipids were more characteristic of the OA/T2DM+ phenotype. The data also pointed out differences in phospholipid content between superficial and deep layers of the cartilage. Our study shows distinctively different lipid and protein profiles between OA/T2DM- and OA/T2DM+ human cartilage, demonstrating the importance of subclassification of the OA disease for better personalized treatments.

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.

Prospection of plasma proteins as biomarkers for diabetes mellitus monitoring

Purpose

This prospective study aimed to detect and identify plasma proteins differentially expressed between groups of Brazilian diagnosed with type 1 (T1DM), type 2 (T2DM) diabetes with good and poor glycemic control and the non-diabetic group denominated control group (CG).

Methods

Patients with T1DM and T2DM were subdivided according to their glycated haemoglobin (HbA_1c) level: ≥ 53 mmol/mol and < 53 mmol/mol. Each subgroup was composed of ten subjects (n = 10). The plasma from each subgroup was pooled and depleted of albumin and IgG. The reminiscent proteins were quantified and separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The relative volume of protein bands was determined by densitometry analysis, and those with differential abundance were identified by MALDI-TOF mass spectrometry.

Results

Alpha 2 - Macroglobulin (AMG) was 1.3-fold more abundant in T1DM with HbA_1c ≥ 53 mmol/mol and < 53 mmol/mol and 1.4-fold more abundant in T2DM with HbA_1c ≥ 53 mmol/mol compared to CG. Ceruloplasmin (Cp) and Haptoglobin (Hp) were overexpressed above 1.5-fold in all DM subgroups. Cp in T1DM and Hp in both types of DM were more expressed in HbA_1c ≥ 53 mmol/mol than <53 mmol/mol. Apolipoprotein A-I (Apo A-I) was upregulated only in T2DM subgroups.

Conclusion

In summary, three positive acute-phase proteins, AMG, Cp and Hp were more abundant in diabetic individuals regardless of the diabetes type. The highest Hp abundance in both types of DM with HbA_1c ≥ 53 mmol/mol, reinforces Hp as a possible biomarker associated with diabetic complications.

Apolipoprotein B and non-high-density lipoprotein cholesterol reveal a high atherogenicity in individuals with type 2 diabetes and controlled low-density lipoprotein-cholesterol

Background

Lipid-lowering therapy is guided by Low-density-lipoprotein cholesterol (LDL-c) levels, although the cardiovascular disease (CVD) risk could be better reflected by other lipid parameters. This study aimed at comparing a comprehensive lipid profile between patients with type 2 diabetes mellitus (T2DM) with LDL-c concentration within and above target.

Methods

A comprehensive lipid profile was characterized in 96 T2DM patients. The European Society of Cardiology/European Atherosclerosis Society (ESC/EAS) 2016 and 2019 Guidelines for the Management of Dyslipidemias were used to define LDL-c targets.

Results

In this population, only 28.1 and 16.7% of patients had mean LDL-c levels within target, as defined by the 2016 and 2019 guidelines, respectively. Applying the 2016 guidelines criteria, in patients with LDL-c within target, 22, 25 and 44% presented non-high-density lipoprotein cholesterol (non-HDL-c), Apolipoprotein B (ApoB) and oxidized LDL-c levels above the recommended range, respectively, whereas according to the 2019 guidelines criteria, 50, 39 and 44% of the patients with LDL-c within target had elevated high-density lipoprotein cholesterol (HDL-c), ApoB and oxidized LDL-c levels, respectively. LDL-c was strongly correlated with non-HDL-c (r = 0.850), ApoB (r = 0.656) and oxidized LDL-c (r = 0.508). Similarly, there was a strong correlation between non-HDL-c with both ApoB (r = 0.808) and oxidized LDL-c (r = 0.588).

Conclusions

These findings emphasize the limitations of only considering LDL-c concentration for cardiovascular (CV) risk assessment. Targeting only LDL-c could result in missed opportunities for CV risk reduction in T2DM patients. These data suggest that non-HDL-c, ApoB and oxidized LDL-c levels could be considered as an important part of these patients’ evaluation allowing for a more accurate estimation of CV risk and hopefully better management of these high-risk patients.

A Review of Recent Evidence from Meal-Based Diet Interventions and Clinical Biomarkers for Improvement of Glucose Regulation

In recent decades, the prevalence of diabetes has rapidly increased worldwide. Medical nutrition therapy has been identified as a major therapeutic support for diabetic patients, while preventive strategies in prediabetic or high-risk individuals have mainly focused on supplementation with bioactive compounds. Recently, meal-based interventions have been investigated as novel and safe long-term strategies for improving glucose regulation. However, evaluation of meal-based interventions is difficult since it requires analysis of sensitive markers. Biomarkers can also be used to identify individuals at risk for diabetes, which is important for disease prevention. In this review, we summarize current evidence from meal-based intervention studies conducted with the aim of improving glucose homeostasis in individuals at risk of diabetes using clinical biomarkers currently used to assess diabetic risk. Very low-calorie diets have significantly improved glucose regulation in obese adults and in adults with type 2 diabetes mellitus. In particular, changing the ratios of macronutrients through calorie restriction reduces fasting glucose level and hemoglobin A1c levels in patients with diabetes mellitus. However, this effect is limited in both obese and healthy adults. To date, multiple glucose-related markers have been identified as clinical biomarkers of diabetes. Additional clinical biomarkers include cholesterol levels, hematological markers, and inflammatory markers. Taken together, the evidence presented in this review may help for selection of clinical biomarkers for meal-based preventive approaches for non- or pre-diabetic individuals to prevent onset of diabetes.

Apolipoprotein A-I primes beta cells to increase glucose stimulated insulin secretion

The increase of plasma levels of high-density lipoproteins and Apolipoprotein A-I (ApoA-I), its main protein component, has been shown to have a positive action on glucose disposal in type 2 diabetic patients. The current study investigates the unexplored function of ApoA-I to prime beta cells for improved insulin secretion. INS-1E rat clonal beta cells as well as isolated murine islets were used to study the effect of ApoA-I on responsiveness of the beta cells to high glucose challenge. Confocal and transmission electron microscopy were used to dissect ApoA-I mechanisms of action. Chemical endocytosis blockers were used to understand the role of ApoA-I internalization in mediating its positive effect. Pre-incubation of beta cells and isolated murine islets with ApoA-I augmented glucose stimulated insulin secretion. This effect appeared to be due to an increased reservoir of insulin granules at the cell membrane, as confirmed by confocal and transmission electron microscopy. Moreover, ApoA-I induced pancreatic and duodenal homeobox 1 (PDX1) shuttling from the cytoplasm to the nucleus, with the subsequent increase in the proinsulin processing enzyme protein convertase 1 (PC1/3). Finally, the blockade of ApoA-I endocytosis in beta cells resulted in a loss of ApoA-I positive action on insulin secretion. The proposed mechanisms of the phenomenon here described include ApoA-I internalization into beta cells, PDX1 nuclear translocation, and increased levels of proinsulin processing enzymes. Altogether, these events lead to an increased number of insulin granules.

[Antidiabetic role of high density lipoproteins]

Disturbance in lipid metabolism can be both a cause and a consequence of the development of diabetes mellitus (DM). One of the most informative indicator of lipid metabolism is the ratio of atherogenic and antiatherogenic fractions of lipoproteins and their protein components. The review summarizes literature data and own results indicating the important role of high-density lipoprotein (HDL) and their main protein component, apolipoprotein A-I (apoA-I), in the pathogenesis of type 2 DM. On the one hand, HDL are involved in the regulation of insulin secretion by b-cells and insulin-independent absorption of glucose. On the other hand, insulin resistance and hyperglycemia lead to a decrease in HDL levels and cause modification of their protein component. In addition, HDL, possessing anti-inflammatory and mitogenic properties, provide anti-diabetic protection through systemic mechanisms. Thus, maintaining a high concentration of HDL and apoA-I in blood plasma and preventing their modification are important issues in the context of prevention and treatment of diabetes.

Multivariate analysis of genomics data to identify potential pleiotropic genes for type 2 diabetes, obesity and dyslipidemia using Meta-CCA and gene-based approach

Previous studies have demonstrated the genetic correlations between type 2 diabetes, obesity and dyslipidemia, and indicated that many genes have pleiotropic effects on them. However, these pleiotropic genes have not been well-defined. It is essential to identify pleiotropic genes using systematic approaches because systematically analyzing correlated traits is an effective way to enhance their statistical power. To identify potential pleiotropic genes for these three disorders, we performed a systematic analysis by incorporating GWAS (genome-wide associated study) datasets of six correlated traits related to type 2 diabetes, obesity and dyslipidemia using Meta-CCA (meta-analysis using canonical correlation analysis). Meta-CCA is an emerging method to systematically identify potential pleiotropic genes using GWAS summary statistics of multiple correlated traits. 2,720 genes were identified as significant genes after multiple testing (Bonferroni corrected p value < 0.05). Further, to refine the identified genes, we tested their relationship to the six correlated traits using VEGAS-2 (versatile gene-based association study-2). Only the genes significantly associated (Bonferroni corrected p value < 0.05) with more than one trait were kept. Finally, 25 genes (including two confirmed pleiotropic genes and eleven novel pleiotropic genes) were identified as potential pleiotropic genes. They were enriched in 5 pathways including the statin pathway and the PPAR (peroxisome proliferator-activated receptor) Alpha pathway. In summary, our study identified potential pleiotropic genes and pathways of type 2 diabetes, obesity and dyslipidemia, which may shed light on the common biological etiology and pathogenesis of these three disorders and provide promising insights for new therapies.

Site-specific glycations of apolipoprotein A-I lead to differentiated functional effects on lipid-binding and on glucose metabolism

Prolonged hyperglycemia in poorly controlled diabetes leads to an increase in reactive glucose metabolites that covalently modify proteins by non-enzymatic glycation reactions. Apolipoprotein A-I (apoA-I) of high-density lipoprotein (HDL) is one of the proteins that becomes glycated in hyperglycemia. The impact of glycation on apoA-I protein structure and function in lipid and glucose metabolism were investigated. ApoA-I was chemically glycated by two different glucose metabolites (methylglyoxal and glycolaldehyde). Synchrotron radiation and conventional circular dichroism spectroscopy were used to study apoA-I structure and stability. The ability to bind lipids was measured by lipid-clearance assay and native gel analysis, and cholesterol efflux was measured by using lipid-laden J774 macrophages. Diet induced obese mice with established insulin resistance, L6 rat and C2C12 mouse myocytes, as well as INS-1E rat insulinoma cells, were used to determine in vivo and in vitro glucose uptake and insulin secretion. Site-specific, covalent modifications of apoA-I (lysines or arginines) led to altered protein structure, reduced lipid binding capability and a reduced ability to catalyze cholesterol efflux from macrophages, partly in a modification-specific manner. The stimulatory effects of apoA-I on the in vivo glucose clearance were negatively affected when apoA-I was modified with methylglyoxal, but not with glycolaldehyde. The in vitro data showed that both glucose uptake in muscle cells and insulin secretion from beta cells were affected. Taken together, glycation modifications impair the apoA-I protein functionality in lipid and glucose metabolism, which is expected to have implications for diabetes patients with poorly controlled blood glucose.