Anti-inflammatory Effects of Statins in Patients with Aortic Stenosis

Intermedin1-53 Ameliorates Homocysteine-Promoted Atherosclerotic Calcification by Inhibiting Endoplasmic Reticulum Stress

Aim:

Vascular calcification (VC) is thought to be an independent predictor of cardiovascular morbidity and mortality. Intermedin1-53 (IMD) is a cardiovascular protective peptide and can inhibit vascular medial calcification in rats. In this study, we investigated the effect of IMD on atherosclerotic calcification induced by a high-fat diet plus homocysteine (Hcy) and the potential mechanisms.

Methods:

ApoE−/− mice were fed a high-fat diet with Hcy in drinking water to induce atherosclerotic calcification.

Results:

As compared to the high-fat diet alone, Hcy treatment significantly increased atherosclerotic lesion areas and the number of calcified nodules in aortic roots and was reduced by IMD infusion or 4-phenylbutyric acid (PBA) treatment. In vitro, as compared to calcifying medium alone, Hcy treatment further increased alkaline phosphatase activity, calcium content, and calcium nodule number in human aorta vascular smooth muscle cells (HA-VSMCs), all blocked by IMD or PBA pretreatment. Mechanistically, IMD or PBA significantly alleviated endoplasmic reticulum stress (ERS) activation compared with Hcy treatment. In parallel, IMD or PBA attenuated the messenger RNA levels of osteogenic markers and inflammatory cytokines in aortas and their protein levels in lesions of aortic roots. In vitro, Hcy treatment significantly increased the protein levels of osteoblast-like cell markers in primary rat VSMCs and inflammation markers in mouse peritoneal macrophages, all decreased with IMD or PBA pretreatment. Intermedin1-53 pretreatment also markedly reduced the protein levels of ERS markers in rat VSMCs and mouse peritoneal macrophages.

Conclusions:

Intermedin1-53 protects against Hcy-promoted atherosclerotic calcification in ApoE−/− mice by inhibiting ERS.

Statins and Progression of Calcified Aortic Stenosis

Objective:

To review the evidence evaluating the efficacy of statins in reducing the progression of calcified aortic stenosis (AS).

Data Sources:

MEDLINE, EMBASE, and PubMed were searched (all up to November 2006) for studies evaluating the use of statins to reduce the progression of calcified AS. Search terms included statin, HMG CoA reductase inhibitor, calcified AS, valve stenosis, and calcified stenosis. Additional primary trials were located by searching references noted in review articles.

Study Selection and Data Extraction:

Clinical trials published in the English language were selected for review. Primary efficacy outcomes evaluated were changes in aortic valve measurements, hemodynamic measures of AS, and change in measures of AS severity.

Data Synthesis:

TWO prospective clinical trials and 5 retrospective studies were included in this review. All of the retrospective studies demonstrated that statin use was associated with a statistically significant delay in the progression of AS. One prospective observation trial showed benefit of statin use; however, a large, randomized, double-blind, prospective trial showed no benefit of statin use in decreasing the progression of AS.

Conclusions:

An association between statin use and a delay in AS progression has been observed in retrospective studies; however, prospective trials showed conflicting results. Currently, statins cannot be recommended for medical treatment of AS until larger trials are conducted.

Do statins have a role in reduction/prevention of post-PCI restenosis?

The pathophysiology of post-PCI restenosis involves neointimal formation that consists of three phases: thrombosis (within 24 h), recruitment (3-8 days), and proliferation, which starts on day 8 of PCI. Various factors suggested to be predictors/risks for restenosis include C-reactive protein (CRP), inflammatory mediators (cytokines and adhesion molecules), oxygen radicals, advanced glycation end products (AGEs) and their receptors (RAGE), and soluble RAGE (sRAGE). The earlier noted factors produce thrombogenesis, vascular smooth muscle cell proliferation, and extracellular matrix formation. Statins have pleiotropic effects. Besides lowering serum cholesterol, they have various other biological effects including antiinflammatory, antithrombotic, CRP-lowering, antioxidant, antimitotic, and inhibition of smooth muscle cell proliferation. They inhibit matrix metalloproteinase and cyclooxygenase-2, lower AGEs, decrease expression of RAGE and increase levels of serum sRAGE. They also increase the synthesis of nitric oxide (NO) by increasing endothelial NO synthase expression and activity. Preprocedural statin therapy is known to reduce peri- and post-PCI myonecrosis and reduce the need for repeat revascularization. There is evidence that statin-eluting stents inhibit in-stent restenosis in animal models. It is concluded that because of the above attributes of statins, they are suitable candidates for reduction of post-PCI restenosis and post-PCI myonecrosis. The future directions for the use of statins in reduction of post-PCI restenosis and myonecrosis have been discussed.

Optimal management of familial hypercholesterolemia: treatment and management strategies

Familial hypercholesterolemia is an autosomally dominant disorder caused by various mutations in low-density lipoprotein receptor genes. This will lead to elevated levels of total and low-density lipoprotein cholesterol, which may in turn lead to premature coronary atherosclerosis and cardiac-related death. The symptoms are more severe in the homozygous type of the disease. Different options for the treatment of affected patients are now available. Diet therapy, pharmacologic therapy, lipid apheresis, and liver transplantation are among the various treatments. We clinically review the treatment and management strategies for the disease in order to shed light on the optimal management of familial hypercholesterolemia.

Iron behaving badly: inappropriate iron chelation as a major contributor to the aetiology of vascular and other progressive inflammatory and degenerative diseases

BACKGROUND

The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular 'reactive oxygen species' (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation.

REVIEW

We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation).The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible.This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, since in some circumstances (especially the presence of poorly liganded iron) molecules that are nominally antioxidants can actually act as pro-oxidants. The reduction of redox stress thus requires suitable levels of both antioxidants and effective iron chelators. Some polyphenolic antioxidants may serve both roles.Understanding the exact speciation and liganding of iron in all its states is thus crucial to separating its various pro- and anti-inflammatory activities. Redox stress, innate immunity and pro- (and some anti-)inflammatory cytokines are linked in particular via signalling pathways involving NF-kappaB and p38, with the oxidative roles of iron here seemingly involved upstream of the IkappaB kinase (IKK) reaction. In a number of cases it is possible to identify mechanisms by which ROSs and poorly liganded iron act synergistically and autocatalytically, leading to 'runaway' reactions that are hard to control unless one tackles multiple sites of action simultaneously. Some molecules such as statins and erythropoietin, not traditionally associated with anti-inflammatory activity, do indeed have 'pleiotropic' anti-inflammatory effects that may be of benefit here.

CONCLUSION

Overall we argue, by synthesising a widely dispersed literature, that the role of poorly liganded iron has been rather underappreciated in the past, and that in combination with peroxide and superoxide its activity underpins the behaviour of a great many physiological processes that degrade over time. Understanding these requires an integrative, systems-level approach that may lead to novel therapeutic targets.

Anesthetic Considerations in the Patient With Valvular Heart Disease Undergoing Noncardiac Surgery

Valvular heart disease can be an important finding in patients presenting for noncardiac surgery. Valvular heart disease and resulting comorbidity, such as heart failure or atrial fibrillation, significantly increase the risk for perioperative adverse events. Appropriate preoperative assessment, adequate perioperative monitoring, and early intervention, should hemodynamic disturbances occur, may help prevent adverse events and improve patient outcome. This review article aims to guide the practitioner in the various aspects of anesthetic management in the perioperative care of patients with valvular heart disease. The pharmacological approach to optimization of patient outcome with drugs, such as βblockers and lipid-lowering medications (statins), is an evolving field, and recent developments are discussed in this article.

Ongoing clinical trials of the pleiotropic effects of statins

BACKGROUND

The multiple effects (ie, pleiotropic effects of statins) have received increasing recognition and may have clinical applicability across a broad range of cardiovascular and noncardiovascular conditions.

OBJECTIVE

To determine the relevance and significance of ongoing clinical trials of the pleiotropic effects of statins, focusing on nonlipid effects.

METHOD

Ongoing trials were identified through personal communication, reports presented at scientific meetings (2000-2004), and queries made to AstraZeneca, Bristol-Myers Squibb Co, Merck & Co, Novartis, and Pfizer, manufacturers of the currently marketed statins. Published trials and other source material were identified through electronic searches on MEDLINE (1990-2003), abstract books, and references identified from bibliographies of pertinent articles. Eligible studies were the clinical trials of statins currently under way in which primary or secondary outcomes included the statins' nonlipid (ie, pleiotropic) effect(s). Data were extracted and trial quality was assessed by the authors.

RESULTS

Of the 22 ongoing trials of the nonlipid effects of statins identified, 10 assessed inflammatory markers and plaque stabilization, 4 assessed oxidized low density lipoprotein/vascular oxidant stress, 3 assessed end-stage renal disease, 3 assessed fibrinogen/viscosity, 2 assessed endothelial function, 2 assessed acute coronary syndrome, 2 assessed aortic stenosis progression, and 1 each assessed hypertension, osteoporosis, ischemic burden, Alzheimer's disease, multiple sclerosis, and stroke (outcomes often overlapped).

CONCLUSION

Given the excellent safety and tolerability of statins as a class, full exploration of their pleiotropic effects has the potential to provide additional benefits to many patients.

Supravalvular and valvular aortic stenosis in heterozygous familial hypercholesterolemia

OBJECTIVES

To report calcified aortic stenosis due to hypercholesterolemia in two siblings.

CASE PRESENTATION AND INTERVENTION

A 13-year-old boy with a history of dyspnea on exertion and a systolic murmur of aortic stenosis was referred to our center. Echocardiography showed combined valvular and supravalvular aortic stenoses with a good left ventricle systolic function and severe left ventricular hypertrophy. Two years later his 17-year-old sister was referred to the clinic with similar symptoms. Severe valvular aortic stenosis was detected by echocardiography. Selective coronary angiography showed significant involvement. The father had a history of hypercholesterolemia and confirmed coronary artery disease involving 3 vessels. Angiography showed anterioapical and inferiobasal hypokinesis with preserved left ventricle systolic function. The mother and the other two siblings did not have hyperlipidemia, thereby indicating heterozygous familial hypercholesterolemia in the two affected siblings. The siblings were managed with atrovastatin and nicotinic acid and cholestyramine was added stepwise. The father was treated with lovostatin.

CONCLUSION

This report shows that severe hyperlipidemia in very young patients may be a risk factor for valvulopathy.

A high fat/high carbohydrate diet induces aortic valve disease in C57BL/6J mice

OBJECTIVES

The purpose of this study was to compare aortic valve function and morphology in adult wild-type (WT) mice and in low-density lipoprotein receptor-deficient (LDLr-/-) mice fed or not fed a high-fat/high-carbohydrate (HF/HC) diet.

BACKGROUND

Observations suggest a link between degenerative aortic valve stenosis (AS) and atherosclerosis. Aortic valve stenosis has been successfully induced in animal models of extreme hypercholesterolemia, but these models are less relevant to humans. It is not known if a proatherogenic HF/HC diet without added cholesterol could have the same negative impacts.

METHODS

Forty C57BL/6J mice were divided into four groups: WT + normal diet, WT + HF/HC diet, LDLr-/- with a normal diet, and LDLr-/- with a HF/HC diet. Aortic valve function and histology were evaluated by echocardiography after four months.

RESULTS

Wild-type mice on a HF/HC diet became mildly hypercholesterolemic, obese, and hyperglycemic. As expected, LDLr-/- mice became severely hypercholesterolemic. Both WT and LDLr-/- mice on a HF/HC diet displayed smaller valve areas and higher transvalvular velocities (p < 0.01) after four months. Aortic valve leaflets were thicker and infiltrated with lipids and macrophages in both HF/HC groups.

CONCLUSIONS

A HF/HC diet in mice results in significant aortic valve abnormalities. Putting WT mice on a HF/HC diet reproduced a combination of atherogenic factors (obesity, mild dyslipidemia, and hyperglycemia) more commonly encountered in humans than isolated severe hypercholesterolemia. Severe hypercholesterolemia was not a prerequisite in our model. This experimental model suggests that AS development is multifactorial and that hypercholesterolemia should not be the only target in this disease.

Statin therapy of calcific aortic stenosis: hype or hope?

Calcific aortic stenosis, with a prevalence of 3-9%, is the most frequent heart valve disease and the main cause for valve replacement in patients over 60 years of age. Once thought to be caused by a passive calcium precipitate within the aortic valve leaflets, there is now increasing evidence that development and progression of calcific aortic valve disease may be triggered by underlying genetic and cardiovascular risk factors, and is regulated by an active cellular process involving inflammatory pathways. Targeted drug therapy to prevent the progression of calcific aortic valve disease should ideally be based on the knowledge of risk factors and the molecular pathogenesis of the disease. Conflicting data exists on the potency of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors (i.e. statins) to influence both risk factors and inflammatory pathways by lowering lipid levels and exerting anti-inflammatory properties, respectively. In this review, various aspects of the molecular pathogenesis of calcific aortic stenosis will be summarized and connected with recent experimental and clinical studies that address the potential benefit of the targeted drug therapy by statins in order to prevent the progression of the disease.

Is it time to prescribe statins to patients with calcified aortic stenosis?

Aortic stenosis (AS) is a common disease especially in the older population. It is associated with high mortality and morbidity. Recent data suggest that coronary artery disease and AS share common risk factors. Retrospective studies suggest that statins might slow the progression of AS but there are no randomized clinical trial data available. It would seem that statins can be considered for medical treatment of AS; however, this needs to be investigated in future randomized clinical trials.

The bisphosphonate acute phase response: rapid and copious production of proinflammatory cytokines by peripheral blood gd T cells in response to aminobisphosphonates is inhibited by statins

The bisphosphonates are a novel class of drug that have been registered for various clinical applications worldwide. Bisphosphonates, and in particular the aminobisphosphonates (nBPs), are known to have a number of side-effects including a rise in body temperature and accompanying flu-like symptoms that resemble a typical acute phase response. The mechanism for this response has been partially elucidated and appears to be associated with the release of tumour necrosis factor (TNF)alpha and interleukin (IL)6, although the effector cells that release these cytokines and the mechanism of action remain enigmatic. Here, we show that the nBP-induced acute phase response differs from the typical acute phase response in that CD14+ cells such as monocytes and macrophages are not the primary cytokine producing cells. We show that by inhibiting the mevalonate pathway, nBPs induce rapid and copious production of TNFalpha and IL6 by peripheral blood gammadelta T cells. Prior treatment with statins, which inhibit 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase, blocks nBP-induced production of these proinflammatory cytokines by gammadelta T cells and may offer a means of avoiding the associated acute phase response. In addition, our findings provide a further mechanism for the anti-inflammatory effects attributed to inhibitors of HMG CoA reductase.