HMG-CoA reductase inhibitors deplete circulating classical and non-classical monocytes following human heart transplantation

Optimizing Outcomes in Heart Transplantation: The Role of High-Intensity Statin Therapy

Heart transplantation is a vital procedure for patients with end-stage heart failure, but it faces significant challenges, including graft dysfunction, rejection, and cardiac allograft vasculopathy (CAV), which can compromise long-term graft success. Research suggests that statin therapy may offer significant benefits to heart transplant recipients, such as improved long-term survival and reduced rates of graft rejection and mortality. The aim of this review is to thoroughly examine the recent literature on this topic since 2005. Early use of high-dose statins appears to be particularly effective in preventing vasculopathy and improving outcomes, although a titrated approach may help to reduce side effects. High-dose statins may provide superior cardiovascular benefits, including lower rates of CVD, slower progression of CVD and improved long-term graft survival. Despite potential concerns about adverse effects, evidence suggests that high-intensity statins improve cholesterol levels without increasing serious adverse events after transplantation. The goal of statin therapy in heart transplant recipients is to balance the well-established benefits seen in the general population with the specific needs of this group, with the ultimate goal of improving both longevity and quality of life.

A Systematic Review and Meta-Analysis of the Effects of Statin Therapy on Heart Transplantation

BACKGROUND

Most of the mortality after Heart Transplantation (HT) is attributed to severe cardiac allograft vasculopathy (CAV) and rejection.

OBJECTIVES

This meta-analysis aimed to investigate the effects of postoperative statin therapy on outcomes (mortality, rejection, and CAV in HT patients).

METHODS

This systematic review and meta-analysis was performed on publications between 1980 and October 2023 in Web of Science, Scopus, PubMed, Cochrane, Science Direct, Google Scholar, and Embase databases. Heterogeneity was assessed using Chi-square, I2, and forest plots. Publication bias was evaluated using Begg's and Egger's tests. Analyses were performed in Stata 15 with significance at p < 0.05.

RESULTS

This meta-analysis included 17 studies comprising 4,627 participants and conducted between 1995 to 2021. Compared to non-users, the odds of mortality were lower among statin users (OR= 0.49, 95% CI: 0.32-0.75, p < 0.001). The odds of CAV were also reduced with statin use (OR= 0.71, 95% CI: 0.53-0.96, p = 0.027). The odds of rejection were not significantly different (OR= 0.69, 95% CI: 0.41-1.15, p = 0.152). However, rejection odds were lower with statins in RCTs (OR= 0.42, 95% CI: 0.21-0.82, p = 0.012) but not in case-control studies (OR= 0.87, 95% CI: 0.49-1.52, p = 0.615). No publication bias was observed with Begg's test, but Egger's test showed possible bias.

CONCLUSION

This meta-analysis found postoperative statin use associated with lower mortality and CAV, but not overall rejection, though RCT subgroup analysis showed decreased rejection with statins. Statin therapy may improve prognosis in HT patients.

Effect of Rosuvastatin Therapy on Biomarkers of Inflammation and Immune Activation in People With Human Immunodeficiency Virus at Intermediate Cardiovascular Risk

BACKGROUND

Statins may help prevent cardiovascular disease (CVD) in people with human immunodeficiency virus (PWH) with chronic inflammation owing to their pleotropic lipid-lowering and anti-inflammatory properties.

METHODS

The impact of 48 weeks of rosuvastatin therapy on inflammation and immune activation in a double-blind, placebo-controlled trial in PWH at moderate cardiovascular disease risk was assessed.

RESULTS

Rosuvastatin did not alter plasma levels of interleukin 6, soluble tumor necrosis factor receptor type 2, CXCL10, soluble CD14, or soluble vascular cellular adhesion molecule 1 (P ≥ .1 for all). Proportions of CD16+ monocyte subsets were increased in PWH receiving rosuvastatin.

CONCLUSIONS

The potential benefits of statin use in PWH with normal lipid levels requires further clinical outcome research.

Monocyte-mediated drug delivery systems for the treatment of cardiovascular diseases

Major advances have been achieved in understanding the mechanisms and risk factors leading to cardiovascular disorders and consequently developing new therapies. A strong inflammatory response occurs with a substantial recruitment of innate immunity cells in atherosclerosis, myocardial infarction, and restenosis. Monocytes and macrophages are key players in the healing process that ensues following injury. In the inflamed arterial wall, monocytes, and monocyte-derived macrophages have specific functions in the initiation and resolution of inflammation, principally through phagocytosis, and the release of inflammatory cytokines and reactive oxygen species. In this review, we will focus on delivery systems, mainly nanoparticles, for modulating circulating monocytes/monocyte-derived macrophages. We review the different strategies of depletion or modulation of circulating monocytes and monocyte subtypes, using polymeric nanoparticles and liposomes for the therapy of myocardial infarction and restenosis. We will further discuss the strategies of exploiting circulating monocytes for biological targeting of nanocarrier-based drug delivery systems for therapeutic and diagnostic applications.

Immunotropic Effects and Proposed Mechanism of Action for 3-Hydroxy-3-methylglutaryl-coenzyme A Reductase Inhibitors (Statins)

Inhibitors of HMG-CoA reductase (statins) are the major group of lipid-lowering drugs. Along with hypocholesterolemic activity, statins exhibit anti-inflammatory and immunomodulatory properties that expand their clinical use, particularly, in the treatment of chronic inflammatory and autoimmune disorders. In this review, we critically analyze the data of statin effects on immune cells (e.g., monocytes and T cells) involved in the development of atherosclerosis and other chronic inflammatory diseases. We (i) discuss the properties of statins and routes of cell entry, as well as their major intracellular targets; (ii) evaluate the data on the effects of statins on the subset composition of circulatory monocytes, ability of monocytes to migrate to the site of inflammation (cell motility and expression of adhesion molecules and chemokine receptors), production of cytokines, matrix metalloproteinases, and reactive oxygen species by monocytes/macrophages, and antigen-presenting activity in peripheral blood monocyte-derived dendritic cells; and (iii) summarize the data on the regulation of proliferation and differentiation of various CD4+ T cell subsets (type 1/2/17 helper T cells and regulatory T cells) by statins.

Lymphocyte and monocyte subpopulations in severe aortic stenosis at the time of surgical intervention

INTRODUCTION

Aortic stenosis (AS) is the most common acquired valvular heart disease in adults. Immune system involvement becomes evident during AS development. We sought to investigate the role of different circulating lymphocyte and monocyte subpopulations, with focus on CD4⁺CD8⁺ and natural killer T (NKT) cells, in AS.

MATERIAL AND METHODS

Blood samples and aortic valves were obtained from patients undergoing elective aortic valve surgery. Valves were dissected and underwent genetic analyses and calcium content assessment. Lymphocytes and monocytes subsets were assessed by flow cytometry.

RESULTS

Thirty-eight AS patients were studied. Maximal transvalvular pressure gradient (PG_max) as well as mean transvalvular pressure gradient (PG_mean) correlated with the CD4⁺CD8⁺ lymphocyte count (r=0.35, P=.03 and r=0.43, P=.006, respectively) and fraction (r=0.43, P=.007 and r=0.48, P=.002, respectively). PG_max and PG_mean correlated with CD16⁺CD56⁺CD3⁺ NKT cell count (r=0.39, P=.01 and r=0.43, P=.007, respectively) and fraction (r=0.49, P=.002 and r=0.47, P=.003, respectively). The classical monocyte subpopulation increased after the surgery by 68% (P<.0001). Patients after mini-sternotomy surgery had 47% lower nonclassical monocyte counts than those with full-sternotomy (P=.03). Patients treated with statins had significantly lower postoperative levels of both classical (-25%, P=.04) and nonclassical monocytes (-37%, P=.004) than nontreated individuals.

CONCLUSIONS

In patients with severe isolated AS, CD4⁺CD8⁺ T cells and CD16⁺CD56⁺CD3⁺ NKT cells are associated with AV pressure gradients. Postoperative monocyte levels are affected by procedure invasiveness and use of statins.

Anti-inflammatory and Anti-resorptive Effects of Atorvastatin on Alveolar Bone Loss in Wistar Rats

The aim of this study was to evaluate the anti-inflammatory and anti-resorptive effect of atorvastatin (ATV) in an experimental alveolar bone loss (ABL) model. Wistar rats were subjected to ligature placement around the maxillary second molar for 11 days. The animals received 0.9% saline (2 mL/kg) or ATV (0.3, 3 or 27 mg/kg) daily by gavage. ABL was evaluated by resorption area and histopathological analysis. Serum bone-specific alkaline phosphatase (BALP) activity was also evaluated. Leukogram was performed at 0 h, 6th h, 2nd, 7th and 11th days. Kidney and liver conditions and the body mass variation were analyzed. ATV (3 and 27 mg/kg) inhibited ABL by 39% and 56%, respectively. Histopathological analysis showed that ATV 27 mg/kg prevented ABL and cemental resorption, and inflammatory cell infiltration induced by ligature. ATV (27 mg/kg) prevented serum BALP levels reduction. ATV (27 mg/kg) prevented leukocytosis and did not affect either kidney or liver function nor body mass weight. ATV showed a protecting effect in the ligature-induced periodontitis, without affecting system parameters, by inhibition of inflammatory process and by its anabolic activity on the alveolar bone.

Pediatric Statin Administration: Navigating a Frontier with Limited Data

Increasingly, children and adolescents with dyslipidemia qualify for pharmacologic intervention. As they are for adults, 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase inhibitors (statins) are the mainstay of pediatric dyslipidemia treatment when lifestyle modifications have failed. Despite the overall success of these drugs, the magnitude of variability in dose-exposure-response profiles contributes to adverse events and treatment failure. In children, the cause of treatment failures remains unclear. This review describes the updated guidelines for screening and management of pediatric dyslipidemia and statin disposition pathway to assist the provider in recognizing scenarios where alterations in dosage may be warranted to meet patients' specific needs.

The role of statins in patients after heart transplantation

Numerous studies have shown that statin therapy initiated early after heart transplantation improves the short- and long-term prognosis, leading to a reduction in the incidence of cardiac allograft vasculopathy (CAV), acute rejection episodes and significantly lowers the incidence of cancer in this patient population. The molecular mechanisms responsible for the beneficial effects of statins in patients after heart transplantation are complex; the effectiveness of statins is associated not only with their hypolipemic action, but also with their pleiotropic properties. Statins have been shown to exert protective and therapeutic effects against cancer because they act as antiproliferative agents, promoting apoptosis and inhibiting angiogenesis. Moreover, they reduce the number of circulating monocytes, which inhibits the secretion of proinflammatory cytokines, growth factors, adhesion molecules, chemokines, and matrix metalloproteinases, preventing chronic rejection and CAV. For these reasons, statins should be used as part of standard therapy in patients after heart transplantation.

Oxidative stress and inflammation are differentially affected by atorvastatin, pravastatin, rosuvastatin, and simvastatin on lungs from mice exposed to cigarette smoke

Our aim was to investigate the effects of four different statins on acute lung inflammation induced by cigarette smoke (CS). C57BL/6 male mice were divided into a control group (sham-smoked) and mice exposed to CS from 12 cigarettes/day for 5 days. Mice exposed to CS were grouped and treated with vehicle (i.p.), atorvastatin (10 mg/kg), pravastatin (10 mg/kg), rosuvastatin (5 mg/kg), or simvastatin (20 mg/kg). Treatment with statins differentially improved the pulmonary response when compared to the CS group. Atorvastatin and pravastatin demonstrated slightly effects on inflammation and oxidative stress. Rosuvastatin demonstrated the best anti-inflammatory effect, whereas simvastatin demonstrated the best antioxidant response.

Association of small dense LDL serum levels and circulating monocyte subsets in stable coronary artery disease

Objective

Atherosclerosis is considered to be an inflammatory disease in which monocytes and monocyte-derived macrophages play a key role. Circulating monocytes can be divided into three distinct subtypes, namely in classical monocytes (CM; CD14++CD16-), intermediate monocytes (IM; CD14++CD16+) and non-classical monocytes (NCM; CD14+CD16++). Low density lipoprotein particles are heterogeneous in size and density, with small, dense LDL (sdLDL) crucially implicated in atherogenesis. The aim of this study was to examine whether monocyte subsets are associated with sdLDL serum levels.

Methods

We included 90 patients with angiographically documented stable coronary artery disease and determined monocyte subtypes by flow cytometry. sdLDL was measured by an electrophoresis method on polyacrylamide gel.

Results

Patients with sdLDL levels in the highest tertile (sdLDL≥4mg/dL;T3) showed the highest levels of pro-inflammatory NCM (15.2±7% vs. 11.4±6% and 10.9±4%, respectively; p<0.01) when compared with patients in the middle (sdLDL=2-3mg/dL;T2) and lowest tertile (sdLDL=0-1mg/dL;T1). Furthermore, patients in the highest sdLDL tertile showed lower CM levels than patients in the middle and lowest tertile (79.2±8% vs. 83.9±7% and 82.7±5%; p<0.01 for T3 vs. T2+T1). Levels of IM were not related to sdLDL levels (5.6±4% vs. 4.6±3% vs. 6.4±3% for T3, T2 and T1, respectively). In contrast to monocyte subset distribution, levels of circulating pro- and anti-inflammatory markers were not associated with sdLDL levels.

Conclusion

The atherogenic lipoprotein fraction sdLDL is associated with an increase of NCM and a decrease of CM. This could be a new link between lipid metabolism dysregulation, innate immunity and atherosclerosis.

The effect of statins on cardiac allograft survival

PURPOSE

In addition to having a lipid-lowering effect, statins also have an anti-inflammatory effect that may reduce allograft dysfunction by preventing cardiac allograft vasculopathy (CAV) and play an immunomodulatory role. We studied the effect of statins on cardiac allograft survival at the National Taiwan University Hospital (NTUH).

MATERIALS AND METHODS

We retrospectively reviewed the patients undergoing heart transplantation at NTUH in the last 6 years. After transplantation, all patients received biochemical monitoring every month and echocardiographic examination regularly at NTUH. Protocol biopsy was performed in all except 18 pediatric patients. All patients received immunosuppressants, including tacrolimus or cyclosporine, everolimus or mycophenolate acid, and prednisolone. They were divided into statin and nonstatin groups according to whether or not a statin was taken.

RESULTS

At NTUH, from 2007 to 2012, 168 heart transplantations were performed. The ages of the patients ranged from 6 to 74 years old with male predominance. The etiology was mainly dilated cardiomyopathy (52.4%) and ischemic cardiomyopathy (39.3%), including 7 retransplantations from severe CAV with heart failure. Twenty-three patients (17%) suffered from acute rejection. The overall 1-year actuarial survival rate was 86% ± 2% and the 5-year survival rate was 79% ± 3%. Seventy-eight patients (57.4%) took statins and the statin group has a better 5-year survival rate and freedom from cardiac death survival rate (P < .01).

CONCLUSION

Our study showed that the use of statins after transplantation was associated with better survival.

The role of monocyte phenotype switching in peri-procedural myocardial injury and its involvement in statin therapy

Peri-procedural myocardial injury, which is associated with worse long-term clinical outcome, is a common complication related to inflammatory pathogenetic mechanisms. Monocytes and macrophages play key roles in the initiation and progression of atherosclerosis. Recent studies have demonstrated that monocytes in human peripheral blood are heterogeneous, including CD14⁺CD16⁻ monocytes and CD14⁺CD16⁺ monocytes. Several lines of evidence suggested that CD14⁺CD16⁺ monocytes might contribute to the accelerated atherosclerosis. In view of the heightened appreciation of the heterogeneity of circulating monocytes, we hypothesized that an up-shifting subset of CD14⁺CD16⁺ monocytes might be induced by percutaneous coronary intervention (PCI), which subsequently leads to peri-procedural myocardial injury. Moreover, statins loading before PCI could exert anti-inflammatory effects partly by modulating monocyte phenotype and thus prevent peri-procedural myocardial injury.

Correlation between CD14+CD16++ monocytes in peripheral blood and hypertriglyceridemia after allograft renal transplantation

BACKGROUND

Cardio-cerebrovascular diseases are key factors causing recipient the death after kidney transplantation (KT). Hypertriglyceridemia (HTG), a complication commonly occurring among KT patients, is a major risk factor for cardio-cerebrovascular diseases. The objective of this study was to examine the correlation between peripheral CD14+CD16++ monocytes in KT patients and blood lipids as well as factors affecting hyperglycemia, seeking to understand mechanisms of inflammatory immune reactions.

METHODS

KT patients (n = 60) were divided into subjects with HTG (n = 35) versus without HTG (n = 25). A cohort of healthy participants (55 cases) was divided into the cases without (n = 30) versus with HTG (n = 25). The proportion of peripheral CD14+CD16 ++ monocytes was determined using flow cytometry and hematology, and biochemical indicators were measured by conventional methods. We correlated HTG with these indicators.

RESULTS

The proportion of peripheral blood CD14+CD16++ monocytes among the renal transplant group was significantly lower (P < .05) than that of normal controls. The expression of CD14+CD16++ monocytes among transplant recipients positively correlated with triglycerides (R = 0.449 and R = 0.008, respectively).

CONCLUSION

CD14+CD16++ mononcytes in peripheral blood may represent an independent risk factor for HTG after KT.

Liposomal simvastatin attenuates neointimal hyperplasia in rats

Monocytes, macrophages, and inflammation play a key role in the process of neointimal proliferation and restenosis. The present study evaluated whether systemic and transient depletion of monocytes could be obtained by a single intravenous (IV) injection of simvastatin liposomes, for the inhibition of neointima formation. Balloon-injured carotid artery rats (n = 30) were randomly assigned to treatment groups of free simvastatin, simvastatin in liposomes (3 mg/kg), and saline (control). Stenosis and neointima to media ratio (N/M) were determined 14 days following single IV injection at the time of injury by morphometric analysis. Depletion of circulating monocytes was determined by flow cytometry analyzes of blood specimens. Inhibition of RAW264.7, J774, and THP-1 proliferation by simvastatin-loaded liposomes and free simvastatin was determined by the 3-(4, 5-dimethylthiazolyl-2)-2, 5- diphenyltetrazolium bromide assay. Simvastatin liposomes were successfully formulated and were found to be 1.5-2 times more potent than the free drug in suppressing the proliferation of monocytes/macrophages in cell cultures of RAW 264.7, J774, and THP-1. IV injection of liposomal simvastatin to carotid-injured rats (3 mg/kg, n = 4) resulted in a transient depletion of circulating monocytes, significantly more prolonged than that observed following treatment with free simvastatin. Administration to balloon-injured rats suppressed neointimal growth. N/M at 14 days was 1.56 +/- 0.16 and 0.90 +/- 0.12, control and simvastatin liposomes, respectively. One single systemic administration of liposomal simvastatin at the time of injury significantly suppresses neointimal formation in the rat model of restenosis, mediated via a partial and transient depletion of circulating monocytes.

Ezetimibe and atorvastatin both immunoregulate CD4+ T cells from cardiac transplant recipients invitro

BACKGROUND

Statins are LDL lowering agents that reduce cardiac allograft vasculopathy (CAV) incidence after cardiac transplantation. Furthermore, 'pleiotropic effects' including immunomodulation have been demonstrated by statins following transplantation. It has also been previously suggested that ezetimibe may exert specific effects on the innate immune system in vitro. We compared the effects of ezetimibe and atorvastatin on T lymphocytes in vitro on the justification that these cells are implicated in the pathogenesis of atherosclerosis, allograft rejection and CAV.

METHODS

Peripheral blood mononuclear cells (PBMCs) were isolated from 30 cardiac transplant recipients and co-cultured with the study drug (or placebo) over 48 h. In total, 150 cultures were performed (5 per patient). Drug concentrations were calculated to simulate 10 mg or 100 mg daily in a 70 kg adult. Flow cytometry was performed to analyse T lymphocyte counts and functional characteristics.

RESULTS

Ezetimibe reduced the standard CD3+CD4+ T cell count and CD3+CD4+CD45ro T memory count by dose linear effect (p < 0.001). Atorvastatin also reduced the CD3+CD4+ T cell count and CD3+CD4+CD45ro T memory count by dose linear effect (p = 0.005). Neither drug affected CD3+CD8+ cytotoxic T cells.

DISCUSSION

Both atorvastatin and ezetimibe may have selective immunomodulatory properties independent of their mechanisms of LDL lowering, given that both drugs affect CD4 T helper cells but have no effect on CD8 cytotoxic lymphocytes in vitro. Although speculative, both of these agents could potentially offer benefits to the transplant patient by modulating important components of the adaptive immune system. CD4+ cells in particular are implicated in both CAV and rejection processes.