Cardiovascular disease predictors and adipose tissue macrophage polarization: Is there a link?

Mitochondrial dynamics and metabolism in macrophages for cardiovascular disease: A review

BACKGROUND

Mitochondria regulate macrophage function, affecting cardiovascular diseases like atherosclerosis and heart failure. Their dynamics interact with macrophage cell death mechanisms, including apoptosis and necroptosis.

PURPOSE

This review explores how mitochondrial dynamics and metabolism influence macrophage inflammation and cell death in CVDs, highlighting therapeutic targets for enhancing macrophage resilience and reducing CVD pathology, while examining molecular pathways and pharmacological agents involved.

STUDY DESIGN

This is a narrative review that integrates findings from various studies on mitochondrial dynamics and metabolism in macrophages, their interactions with the endoplasmic reticulum (ER) and Golgi apparatus, and their implications for CVDs. The review also considers the potential therapeutic effects of pharmacological agents on these pathways.

METHODS

The review utilizes a comprehensive literature search to identify relevant studies on mitochondrial dynamics and metabolism in macrophages, their role in CVDs, and the effects of pharmacological agents on these pathways. The selected studies are analyzed and synthesized to provide insights into the complex relationships between mitochondria, the ER, and Golgi apparatus, and their implications for macrophage function and fate.

RESULTS

The review reveals that mitochondrial metabolism intertwines with cellular architecture and function, particularly through its intricate interactions with the ER and Golgi apparatus. Mitochondrial-associated membranes (MAMs) facilitate Ca2+ transfer from the ER to mitochondria, maintaining mitochondrial homeostasis during ER stress. The Golgi apparatus transports proteins crucial for inflammatory signaling, contributing to immune responses. Inflammation-induced metabolic reprogramming in macrophages, characterized by a shift from oxidative phosphorylation to glycolysis, underscores the multifaceted role of mitochondrial metabolism in regulating immune cell polarization and inflammatory outcomes. Notably, mitochondrial dysfunction, marked by heightened reactive oxygen species generation, fuels inflammatory cascades and promotes cell death, exacerbating CVD pathology. However, pharmacological agents such as Metformin, Nitazoxanide, and Galanin emerge as potential therapeutic modulators of these pathways, offering avenues for mitigating CVD progression.

CONCLUSION

This review highlights mitochondrial dynamics and metabolism in macrophage inflammation and cell death in CVDs, suggesting therapeutic targets to improve macrophage resilience and reduce pathology, with new pharmacological agents offering treatment opportunities.

The CaSR/TRPV4 coupling mediates pro-inflammatory macrophage function

AIM

Although calcium-sensing receptor (CaSR) and transient receptor potential vanilloid 4 (TRPV4) channels are functionally expressed on macrophages, it is unclear if they work coordinately to mediate macrophage function. The present study investigates whether CaSR couples to TRPV4 channels and mediates macrophage polarization via Ca²⁺ signaling.

METHODS

The role of CaSR/TRPV4/Ca²⁺ signaling was assessed in lipopolysaccharide (LPS)-treated peritoneal macrophages (PMs) from wild-type (WT) and TRPV4 knockout (TRPV4 KO) mice. The expression and function of CaSR and TRPV4 in PMs were analyzed by immunofluorescence and digital Ca²⁺ imaging. The correlation factors of M1 polarization, CCR7, IL-1β, and TNFα were detected using q-PCR, western blot, and ELISA.

RESULTS

We found that PMs expressed CaSR and TRPV4, and CaSR activation-induced marked Ca²⁺ signaling predominately through extracellular Ca²⁺ entry, which was inhibited by selective pharmacological blockers of CaSR and TRPV4 channels. The CaSR activation-induced Ca²⁺ signaling was significantly attenuated in PMs from TRPV4 KO mice compared to those from WT mice. Moreover, the CaSR activation-induced Ca²⁺ entry via TRPV4 channels was inhibited by blocking phospholipases A2 (PLA2)/cytochromeP450 (CYP450) and phospholipase C (PLC)/Protein kinase C (PKC) pathways. Finally, CaSR activation promoted the expression and release of M1-associated cytokines IL-1β and TNFɑ, which were attenuated in PMs from TRPV4 KO mice.

CONCLUSION

We reveal a novel coupling of the CaSR and TRPV4 channels via PLA2/CYP450 and PLC/PKC pathways, promoting a Ca²⁺ -dependent M1 macrophage polarization. Modulation of this coupling and downstream pathways may become a potential strategy for the prevention/treatment of immune-related disease.

Association of body mass index trajectory and hypertension risk: A systematic review of cohort studies and network meta-analysis of 89,094 participants

Introduction

Body mass index (BMI) trajectories, such as non-linear time trends and nonlinear changes in BMI with age, can provide information on the underlying temporal health patterns. The relationship between BMI trajectories and the risk of hypertension remains controversial.

Methods

PubMed, Embase, Cochrane, Scopus, and Web of Science databases were searched from their inception to January 31, 2022. We categorized BMI trajectories as "Stable high," "table normal," "Stable low," "Fluctuated (sharp increase)," and "Fluctuated (elevated-decrease)." The main outcome was the relative risk for the prevalence of hypertension in the different BMI trajectories. Potential sources of heterogeneity were examined using meta-regression and subgroup analysis. A publication bias test and Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach were also used.

Results

The 18 cohort studies included 89,094 participants. Compared with the "Stable normal" trajectory, "Stable high," "Fluctuated (sharp increase)," and "Fluctuated (elevated-decrease)" trajectories were associated with an increased relative risk of hypertension: [RR (95% CI)]: 1.80 (1.29 2.50), p < 0.001; 1.53 (1.27 1.83), p < 0.001; 1.30 (1.24 1.37), p = 0.001, respectively. The "Stable low" trajectory was associated with a reduced risk of hypertension [0.83 (0.79 0.83), p < 0.001]. The "Stable high" trajectory (surface under the cumulative ranking curve = 88.1%) had the highest probability of developing hypertension in the population. The certainty of the evidence for direct comparisons of the incidence of hypertension between various BMI trajectories was generally very low.

Conclusion

Our findings suggested that "Stable high," "Fluctuated (sharp increase)," and "Fluctuated (elevated-decrease)" trajectories were associated with an increased relative risk of hypertension, with the "Stable high" trajectory most likely associated with hypertension.

Systematic review registration

[https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=308575], identifier [CRD42022308575].

Cholesterol in the Cell Membrane-An Emerging Player in Atherogenesis

Membrane cholesterol is essential for cell membrane properties, just as serum cholesterol is important for the transport of molecules between organs. This review focuses on cholesterol transport between lipoproteins and lipid rafts on the surface of macrophages. Recent studies exploring this mechanism and recognition of the central dogma-the key role of macrophages in cardiovascular disease-have led to the notion that this transport mechanism plays a major role in the pathogenesis of atherosclerosis. The exact molecular mechanism of this transport remains unclear. Future research will improve our understanding of the molecular and cellular bases of lipid raft-associated cholesterol transport.

Association of Chinese Visceral Adiposity Index and Its Dynamic Change With Risk of Carotid Plaque in a Large Cohort in China

Background

We aimed to evaluate the association between the Chinese visceral adiposity index (CVAI) and its dynamic change and risk of carotid plaque based on a large Chinese cohort.

Methods and Results

This cohort included 23 522 participants aged 20 to 80 years without elevated carotid intima‐media thickness and carotid plaque at baseline and who received at least 2 health checkups. CVAI was calculated at baseline and at every checkup. The dynamic change in CVAI was calculated by subtracting CVAI at baseline from that at the last follow‐up. Cox proportional hazard regression model was used to estimate hazard ratios (HRs) and 95% CIs. The restricted cubic spline was applied to model the dose‐response association between CVAI and carotid plaque risk. During the 82 621 person‐years of follow‐up, 5987 cases of carotid plaque developed (7.25/100 person‐years). We observed a significant positive correlation between CVAI and carotid plaque risk (HR, 1.53; 95% CI, 1.48–1.59 [P<0.001]) in a nonlinear dose‐response pattern (P_nonlinearity<0.001). The sensitivity analyses further confirmed the robustness of the results. The association was significant in all subgroup analyses stratified by sex, hypertension, and fatty liver disease except for the diabetes subgroup. The association between CVAI and carotid plaque risk was much higher in men than in women. No significant association was identified between change in CVAI and carotid plaque risk.

Conclusions

CVAI was positively associated with carotid plaque risk in a nonlinear dose‐response pattern in this study. Individuals should keep their CVAI within a normal level to prevent the development of carotid plaque.

Adipose tissue macrophages and atherogenesis – a synergy with cholesterolaemia

Excessive LDL cholesterol concentration together with subclinical inflammation, in which macrophages play a central role, are linked pathologies. The process starts with the accumulation of macrophages in white adipose tissue and the switch of their polarization toward a pro-inflammatory phenotype. The proportion of pro-inflammatory macrophages in adipose tissue is related to the main risk predictors of cardiovascular disease. The cholesterol content of phospholipids of cell membranes seems to possess a crucial role in the regulation of membrane signal transduction and macrophage polarization. Also, different fatty acids of membrane phospholipids influence phenotypes of adipose tissue macrophages with saturated fatty acids stimulating pro-inflammatory whereas ω3 fatty acids anti-inflammatory changes. The inflammatory status of white adipose tissue, therefore, reflects not only adipose tissue volume but also adipose tissue macrophages feature. The beneficial dietary change leading to an atherogenic lipoprotein decrease may therefore synergically reduce adipose tissue driven inflammation.

Extracellular vesicle therapeutics from plasma and adipose tissue

Extracellular vesicles (EVs) are cell-released lipid-bilayer nanoparticles that contain biologically active cargo involved in physiological and pathological intercellular communication. In recent years, the therapeutic potential of EVs has been explored in various disease models. In particular, mesenchymal stromal cell-derived EVs have been shown to exert anti-inflammatory, anti-oxidant, anti-apoptotic, and pro-angiogenic properties in cardiovascular, metabolic and orthopedic conditions. However, a major drawback of EV-based therapeutics is scale-up issues due to extensive cell culture requirements and inefficient isolation protocols. An emerging alternative approach to time-consuming and costly cell culture expansion is to obtain therapeutic EVs directly from the body, for example, from plasma and adipose tissue. This review discusses isolation methods and therapeutic applications of plasma and adipose tissue-derived EVs, highlighting advantages and disadvantages compared to cell culture-derived ones.

Adipose tissue macrophages as a therapeutic target in obesity-associated diseases

Obesity is an increasing problem in developed and developing countries. Individuals with obesity have a higher risk of several diseases, such as cardiovascular disease, increased risk of insulin resistance, type 2 diabetes, infertility, degenerative disorders, and also certain types of cancer. Adipose tissue (AT) is considered an extremely active endocrine organ, and the expansion of AT is accompanied by the infiltration of different types of immune cells, which induces a state of low-grade, chronic inflammation and metabolic dysregulation. Even though the exact mechanism of this low-grade inflammation is not fully understood, there is clear evidence that AT-infiltrating macrophages (ATMs) play a significant role in the pro-inflammatory state and dysregulated metabolism. ATMs represent the most abundant class of leukocytes in AT, constituting 5% of the cells in AT in individuals with normal weight. However, this percentage dramatically increases up to 50% in individuals with obesity, suggesting an important role of ATMs in obesity and its associated complications. In this review, we discuss current knowledge of the function of ATMs during steady-state and obesity and analyze its contribution to different obesity-associated diseases, highlighting the potential therapeutic target of ATMs in these pathological conditions.

Inflammatory Gene Expression in Neck Perivascular and Subcutaneous Adipose Tissue in Men With Carotid Stenosis

The inflammatory phenotype of neck adipose tissue (NAT) might reflect its involvement in the pathogenesis of carotid atherosclerosis. We investigated inflammatory gene expression in the subcutaneous and the perivascular (pericarotid) adipose tissue from patients with carotid stenosis (CS) undergoing endarterectomy and a control group of patients without significant carotid atherosclerosis undergoing thyroid surgery. Only male patients were included (n = 13 in each study group). Clinical and biochemical data along with serum leptin, adiponectin, and monocyte chemoattractant protein 1 (MCP-1) were collected. Adipose tissue samples were obtained from both the subcutaneous and pericarotid compartments. Real-time polymerase chain reaction was used to measure gene expression of macrophage markers and adipokines. The CS group had higher subcutaneous and pericarotid visfatin gene expression and higher pericarotid expression of MCP-1 and CD68 genes. The ratio between pericarotid CD206 and CD68 gene expression was similar between study groups. Adiponectin gene expression in both NAT compartments did not differ between groups, but it was negatively associated with body weight. These observations suggest that NAT, and especially the pericarotid compartment, express enhanced inflammatory properties in patients with CS, but the proportion of anti-inflammatory macrophages in advanced atherosclerosis seems to be maintained.

Statins Directly Influence the Polarization of Adipose Tissue Macrophages: A Role in Chronic Inflammation

Statins represent one of the most widely used classes of drugs in current medicine. In addition to a substantial decrease in atherogenic low density lipoprotein (LDL) particle concentrations, several large trials have documented their potent anti-inflammatory activity. Based on our preliminary data, we showed that statins are able to decrease the proportion of pro-inflammatory macrophages (CD14+16+CD36high) in visceral adipose tissue in humans. In the present study including 118 healthy individuals (living kidney donors), a very close relationship between the pro-inflammatory macrophage proportion and LDL cholesterol levels was found. This was confirmed after adjustment for the most important risk factors. The effect of statins on the proportion of pro-inflammatory macrophages was also confirmed in an experimental model of the Prague hereditary hypercholesterolemia rat. A direct anti-inflammatory effect of fluvastatin on human macrophage polarization in vitro was documented. Based on modifying the LDL cholesterol concentrations, statins are suggested to decrease the cholesterol inflow through the lipid raft of macrophages in adipose tissue and hypercholesterolemia to enhance the pro-inflammatory macrophage phenotype polarization. On the contrary, due to their opposite effect, statins respond with anti-inflammatory activity, affecting the whole organism.

CD36 in Atherosclerosis: Pathophysiological Mechanisms and Therapeutic Implications

PURPOSE OF REVIEW

Atherosclerosis is a chronic disease characterized by lipid retention and inflammation in the artery wall. The retention and oxidation of low-density lipoprotein (LDL) in sub-endothelial space play a critical role in atherosclerotic plaque formation and destabilization. Oxidized LDL (ox-LDL) and other modified LDL particles are avidly taken up by endothelial cells, smooth muscle cells, and macrophages mainly through several scavenger receptors, including CD36 which is a class B scavenger receptor and membrane glycoprotein.

RECENT FINDINGS

Animal studies performed on CD36-deficient mice suggest that deficiency of CD36 prevents the development of atherosclerosis, though with some debate. CD36 serves as a signaling hub protein at the crossroad of inflammation, lipid metabolism, and fatty acid metabolism. In addition, the level of soluble CD36 (unattached to cells) in the circulating blood was elevated in patients with atherosclerosis and other metabolic disorders. We performed a state-of-the-art review on the structure, ligands, functions, and regulation of CD36 in the context of atherosclerosis by focusing on the pathological role of CD36 in the dysfunction of endothelial cells, smooth muscle cells, monocytes/macrophages, and platelets. Finally, we highlight therapeutic possibilities to target CD36 expression/activity in atherosclerosis.

Added sugar intake is associated with pericardial adipose tissue volume

AIM

The purpose of this study was to determine the relationships of pericardial adipose tissue and visceral adipose tissue volume with added sugar and sugar-sweetened beverage intakes. We hypothesized that both added sugar and sugar-sweetened beverages were positively associated with pericardial adipose tissue and visceral adipose tissue volumes in black and white men and women enrolled in the prospective Coronary Artery Risk Development in Young Adults study.

METHODS AND RESULTS

Dietary intake was assessed by diet history at baseline, year 7 and year 20 examinations in 3070 participants aged 18-30 and generally healthy at baseline. After 25 years follow-up, participants underwent a computed tomography scan of chest and abdomen; the computed tomography scans were read, and pericardial adipose tissue, visceral adipose tissue, and subcutaneous adipose tissue volumes were calculated. Quintiles were created for the average of baseline, year 7 and year 20 added sugar and for the average of sugar-sweetened beverages. General linear regression analysis evaluated the associations of pericardial adipose tissue and visceral adipose tissue volumes across quintiles of added sugar and across quintiles of sugar-sweetened beverage intakes adjusted for potential confounding factors. In a multivariable model, pericardial adipose tissue volume was higher across increasing quintiles of added sugar and sugar-sweetened beverage intakes (p_trend = 0.001 and p_trend < 0.001, respectively). A similar relation was observed for visceral adipose tissue (p_trend < 0.001 for both added sugar and sugar-sweetened beverages).

CONCLUSIONS

Long-term intakes of added sugar and sugar-sweetened beverages were associated with higher pericardial adipose tissue, visceral adipose tissue, and subcutaneous adipose tissue volumes. Because these ectopic fat depots are associated with greater risk of disease incidence, these findings support limiting intakes of added sugar and sugar-sweetened beverages.

The effect of cytokines produced by human adipose tissue on monocyte adhesion to the endothelium

Visceral adipose tissue (VAT) may play a critical role in atherosclerotic cardiovascular disease. The goal of this study was to determine the effect of human VAT-released pro‑inflammatory cytokines on monocyte adhesion to the endothelium. The cytokine effects on monocyte adhesion to the endothelial cells (ECs) were tested using adipose tissue-conditioned media (ATCM) prepared by culturing human VAT. The cytokines concentrations in ATCM, the cytokines expression and adhesion molecules in stimulated ECs were measured. The concentrations of IL-1β,TNF-α,MCP-1,IL-10,and RANTES measured in ATCM correlated positively with monocyte adhesiveness to ECs. Additionally, ATCM increased the adhesion molecules (ICAM-1, VCAM-1) gene expression. Selective inhibitors highlighted the importance of IL-1β and TNF-α in the process by a significant decrease in monocyte adhesion compared to ATCM preconditioning without inhibitors. Human VAT significantly increased monocyte adhesion to ECs. It was significantly influenced by IL-1β, TNF-α, MCP-1, IL-10, and RANTES, with IL-1β and TNF‑α having the strongest impact.

Characterization of glucose uptake metabolism in visceral fat by 18 F-FDG PET/CT reflects inflammatory status in metabolic syndrome

Objective

The inflammatory activity of visceral adipose tissue (VAT) is elevated in metabolic syndrome (MS), and associated with vulnerability to atherosclerosis. Inflammation can be assessed by glucose uptake in atherosclerotic plaques. We investigated whether the glucose uptake of VAT, assessed by ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT), is associated with systemic inflammatory status, and related to the number of MS components.

Methods

¹⁸F-FDG PET/CT was performed in a total of 203 participants: 59 without MS component; M(0), 92 with one or two MS components; M(1–2), and 52 with MS. Glucose uptake in VAT was evaluated using the mean standardized uptake value (SUVmean) and the maximum SUV (SUVmax). Glucose uptakes of immune-related organs such as the spleen and bone marrow (BM) were evaluated using the SUVmax.

Results

VAT SUVmax correlated with high-sensitivity C-reactive protein (hsCRP) and the SUVmax of spleen and BM, which reflect the status of systemic inflammation. Both hsCRP and the SUVmax of the spleen and BM were higher in the MS group than in the M(1–2) or M(0) groups. In VAT, SUVmax increased with increasing number of MS components, while SUVmean decreased.

Conclusions

The SUVmax and SUVmean of VAT assessed by ¹⁸F-FDG PET/CT reflected inflammation-driven unique glucose metabolism in the VAT of MS patients, distinct from that of atherosclerotic plaques.

IgE Contributes to Atherosclerosis and Obesity by Affecting Macrophage Polarization, Macrophage Protein Network, and Foam Cell Formation

OBJECTIVE

By binding to its high-affinity receptor FcεR1, IgE activates mast cells, macrophages, and other inflammatory and vascular cells. Recent studies support an essential role of IgE in cardiometabolic diseases. Plasma IgE level is an independent predictor of human coronary heart disease. Yet, a direct role of IgE and its mechanisms in cardiometabolic diseases remain incompletely understood. Approach and Results: Using atherosclerosis prone Apoe^-/- mice and IgE-deficient Ige^-/- mice, we demonstrated that IgE deficiency reduced atherosclerosis lesion burden, lesion lipid deposition, smooth muscle cell and endothelial cell contents, chemokine MCP (monocyte chemoattractant protein)-1 expression and macrophage accumulation. IgE deficiency also reduced bodyweight gain and increased glucose and insulin sensitivities with significantly reduced plasma cholesterol, triglyceride, insulin, and inflammatory cytokines and chemokines, including IL (interleukin)-6, IFN (interferon)-γ, and MCP-1. From atherosclerotic lesions and peritoneal macrophages from Apoe^-/-Ige^-/- mice that consumed an atherogenic diet, we detected reduced expression of M1 macrophage markers (CD68, MCP-1, TNF [tumor necrosis factor]-α, IL-6, and iNOS [inducible nitric oxide synthase]) but increased expression of M2 macrophage markers (Arg [arginase]-1 and IL-10) and macrophage-sterol-responsive-network molecules (complement C3, lipoprotein lipase, LDLR [low-density lipoprotein receptor]-related protein 1, and TFR [transferrin]) that suppress macrophage foam cell formation. These IgE activities can be reproduced in bone marrow-derived macrophages from wild-type mice, but muted in cells from FcεR1-deficient mice, or blocked by anti-IgE antibody or complement C3 deficiency.

CONCLUSIONS

IgE deficiency protects mice from diet-induced atherosclerosis, obesity, glucose tolerance, and insulin resistance by regulating macrophage polarization, macrophage-sterol-responsive-network gene expression, and foam cell formation.

Modular bioinformatics analysis demonstrates that a Toll‑like receptor signaling pathway is involved in the regulation of macrophage polarization

In recent years, an increasing number of studies on the roles of macrophages in tumors, immune responses and metabolism have been published, in which macrophage polarization has been an extensively discussed topic. In the present study, differentially expressed genes in various types of macrophages were analyzed using the Gene Expression Omnibus database. Cluster analysis of differentially expressed genes was conducted, and a protein-protein interaction (PPI) network was constructed. Finally, modular analysis and functional enrichment analysis revealed that a Toll-like receptor (TLR) signaling pathway is involved in the regulation of macrophage polarization. Furthermore, the high-degree proteins in the PPI network that are involved in the molecular regulation of macrophage polarization are closely associated with proteins of the TLR signaling pathway. These results suggested that the TLR signaling pathways may be a principal direction of future research on the regulation of macrophage polarization.

The relation between body fat distribution, plasma concentrations of adipokines and the metabolic syndrome in patients with clinically manifest vascular disease

Introduction

We evaluated the relationship between adipokine plasma concentrations and body fat distribution and the metabolic syndrome.

Methods

In a cohort of 1215 patients with clinically manifest vascular disease the relation between subcutaneous adipose tissue, visceral adipose tissue, waist circumference, body mass index and plasma concentrations of adipsin, chemerin, monocyte chemoattractant protein-1, migration inhibitory factor, nerve growth factor, resistin, plasma amyloid A1, adiponectin, leptin, plasminogen activator inhibitor-1 and hepatic growth factor were cross-sectionally assessed with linear regression and adjusted for age and gender. The relation between adipokines and the metabolic syndrome was cross-sectionally evaluated using logistic regression. An adipokine profile was developed to measure the effect of combined rather than single adipokines.

Results

Adiposity was related to higher nerve growth factor, hepatic growth factor, migration inhibitory factor, leptin and adipsin and with lower chemerin, plasminogen activator inhibitor-1, resistin, plasma amyloid A1 and adiponectin. The strongest positive relations were between body mass index and adipsin (β 0.247; 95% CI 0.137–0.356) and leptin (β 0.266; 95% CI 0.207–0.324); the strongest negative relations were between body mass index and plasma amyloid A1 (β –0.266; 95% CI –0.386 to –0.146) and visceral adipose tissue and adiponectin (β –0.168; 95% CI –0.226 to –0.111). There was no relation between subcutaneous adipose tissue and adipokines. Odds for the metabolic syndrome were higher with each 1 SD higher hepatic growth factor (OR 1.21; 95% CI 1.06–1.38) and leptin (OR 1.26; 95% CI 1.10–1.45) and lower with each 1 SD higher adiponectin (OR 0.73; 95% CI 0.64–0.83) and resistin (OR 0.85; 95% CI 0.74–0.97). The adipokine profile was related to the metabolic syndrome (OR 1.03; 95% CI 1.00–1.06).

Conclusion

Plasma concentrations of adipokines are related to obesity and body fat distribution. The relation between adipokine concentrations and the metabolic syndrome is independent of visceral adipose tissue.

Functional Implications of HMG-CoA Reductase Inhibition on Glucose Metabolism

HMG-CoA reductase inhibitors, i.e. statins, are effective in reducing cardiovascular disease events but also in cardiac-related and overall mortality. Statins are in general well-tolerated, but currently the concerns are raised if statins may increase the risk of new-onset diabetes mellitus (NOD). In this review, the possible effects of statins on organs/tissues being involved in glucose metabolism, i.e. liver, pancreas, adipose tissue, and muscles, had been discussed. The net outcome seems to be inconsistent and often contradictory, which may be largely affected by in vitro experimental settings or/and in vivo animal conditions. The majority of studies point out statin-induced changes of regulations of isoprenoid metabolites and cell-associated cholesterol contents as predisposing factors related to the statin-induced NOD. On the other hand, it should be considered that dysfunctions of isoprenoid pathway and mitochondrial ATP production and the cholesterol homeostasis are already developed under (pre)diabetic and hypercholesterolemic conditions. In order to connect the basic findings with the clinical manifestation more clearly, further research efforts are needed.