The therapeutic efficacy of intensive medical therapy in ameliorating high-density lipoprotein dysfunction in subjects with type two diabetes

Alterations of HDL's to piHDL's Proteome in Patients with Chronic Inflammatory Diseases, and HDL-Targeted Therapies

Chronic inflammatory diseases, such as rheumatoid arthritis, steatohepatitis, periodontitis, chronic kidney disease, and others are associated with an increased risk of atherosclerotic cardiovascular disease, which persists even after accounting for traditional cardiac risk factors. The common factor linking these diseases to accelerated atherosclerosis is chronic systemic low-grade inflammation triggering changes in lipoprotein structure and metabolism. HDL, an independent marker of cardiovascular risk, is a lipoprotein particle with numerous important anti-atherogenic properties. Besides the essential role in reverse cholesterol transport, HDL possesses antioxidative, anti-inflammatory, antiapoptotic, and antithrombotic properties. Inflammation and inflammation-associated pathologies can cause modifications in HDL's proteome and lipidome, transforming HDL from atheroprotective into a pro-atherosclerotic lipoprotein. Therefore, a simple increase in HDL concentration in patients with inflammatory diseases has not led to the desired anti-atherogenic outcome. In this review, the functions of individual protein components of HDL, rendering them either anti-inflammatory or pro-inflammatory are described in detail. Alterations of HDL proteome (such as replacing atheroprotective proteins by pro-inflammatory proteins, or posttranslational modifications) in patients with chronic inflammatory diseases and their impact on cardiovascular health are discussed. Finally, molecular, and clinical aspects of HDL-targeted therapies, including those used in therapeutical practice, drugs in clinical trials, and experimental drugs are comprehensively summarised.

A systematic review: the appraisal of the effects of metformin on lipoprotein modification and function

AIMS

Metformin is a commonly prescribed anti-hyperglycaemic pharmacological agent, and it remains a staple in the management of type II diabetes. In addition to metformin's glucose lowering effects, research has indicated that metformin inhibits glycation-mediated and oxidative modification of lipoprotein residues. The purpose was to discuss the effects of metformin as it relates to high-density lipoprotein (HDL) and low-density lipoprotein (LDL) modification.

MATERIALS AND METHODS

The purpose was to conduct a narrative and pragmatic review on the effects of metformin as it pertains to HDL and LDL modification.

RESULTS

High-density lipoprotein (HDL) concentration is a quantitative measure and therefore does not provide insight into its function, which is a qualitative property. Dysfunctional HDLs are unable to carry out functions normally associated with HDL because they can be modified by glycating agents. Metformin may counteract HDL dysfunction by abating HDL modification. Reductions in HDL modification may improve reverse cholesterol transport ability and thus possibly diminish cardiovascular risk. Similarly, metformin-mediated attenuations in LDL modification may reduce their atherogenic potency.

CONCLUSION

Metformin may partially ameliorate HDL dysfunction and reduce LDL modification by inhibiting alpha-dicarbonyl-mediated modification of apolipoprotein residues; consequently, the results are salient because cardiovascular disease incidence may be reduced given that reverse cholesterol transport activity predicts risk, and modified LDL are proatherogenic.

Glycation Reduces the Stability of ApoAI and Increases HDL Dysfunction in Diet-Controlled Type 2 Diabetes

CONTEXT

Hyperglycemia plays a key role in the pathogenesis of cardiovascular complications of diabetes. Type 2 diabetes mellitus (T2DM) is associated with high-density lipoprotein (HDL) dysfunction and increased degradation of apolipoprotein I (ApoAI). The mechanism(s) of these changes is largely unknown.

OBJECTIVE

To study the role of hyperglycemia-induced glycation on ApoAI kinetics and stability in patients with diet-controlled T2DM.

DESIGN

2H2O-metabolic labeling approach was used to study ApoAI turnover in patients with diet-controlled T2DM [n = 9 (5 F); 59.3 ± 8.5 years] and matched healthy controls [n = 8 (4 F); 50.7 ± 11.6 years]. The effect of Amadori glycation on in vivo ApoAI stability and the antioxidant and cholesterol efflux properties of HDL were assessed using a proteomics approach and in vitro assays.

RESULTS

Patients with T2DM had increased turnover of ApoAI and impaired cholesterol efflux and antioxidant properties of HDL. Glycated hemoglobin was negatively correlated with the half-life of ApoAI and cholesterol efflux function of HDL. Proteomics analysis identified several nonenzymatic early (Amadori) glycations of ApoAI at lysine sites. The kinetics analysis of glycated and native ApoAI peptides in patients with T2DM revealed that glycation resulted in a threefold shorter ApoAI half-life.

CONCLUSIONS

The 2H2O method allowed the detection of early in vivo impairments in HDL metabolism and function that were related to hyperglycemia-induced glycation of ApoAI in T2DM.