Atherosclerotic Plaque Regression: Fact or Fiction?

Effectiveness of statins on outcomes of patients with Embolic Stroke of Undetermined Source (ESUS)

BACKGROUND

Statins are highly recommended as a secondary prevention strategy after a stroke. Embolic Stroke of Undetermined Source (ESUS) accounts for up to one fifth of cases of ischemic stroke. There is a lack of studies investigating the effectiveness of statins in this subgroup of patients.

METHODS

We designed a longitudinal cohort study involving patients properly diagnosed with ESUS. Data about statin therapy included information about the time of initiation of the treatment, pre-stroke statin use, statin withdrawal, and the type and dosage of the statin prescribed. Patients were followed for 48 months after the index stroke. The primary endpoints included stroke recurrence, major cardiovascular events, and death from all causes. The secondary endpoint was the functional outcome, assessed in a standardized and systematic way using the modified Rankin Scale (mRS).

RESULTS

Patients who were not taking any statin after ESUS have significantly increased odds of stroke recurrence (OR = 3.29, 95% CI 1.27 - 8.55) or presenting the composite outcome of stroke recurrence, major cardiovascular events, and death (OR = 3.70, 95% CI 1.44 - 9.50) in the multivariate analysis. No statin therapy was directly associated with the functional outcome as well (OR = 3.32, 95% CI = 1.58 - 6.96). The early initiation of the statin therapy was estimated to reduce the risk of a second stroke and the composite outcome by 89% and 87%.

CONCLUSIONS

Our pioneering study provides evidence that patients with ESUS may benefit from statin therapy, especially if prescribed early and at higher dosages.

Prognostic value of statin therapy in patients with myocardial infarction with nonobstructive coronary arteries (MINOCA): a meta-analysis

BACKGROUND

Given the complex aetiology and a limited amount of evidence, the medical treatment (including statin use) of myocardial infarction with non-obstructive coronary artery disease (MINOCA) remains uncertain. The objective of the present study was to evaluate the effect of statin therapy on major cardiovascular events (MACE) and mortality in MINOCA patients.

METHODS

A systematic review and meta-analysis of time-to-event outcomes were performed of studies of statin therapy on MINOCA patients, reporting data from MACE or mortality, after searching the PubMed/MEDLINE, Embase, Science Direct, Scopus, Google Scholar, and Cochrane databases. A fixed-effects meta-analysis model was then applied.

RESULTS

Six observational studies of statin therapy on MINOCA, involving a total of 11,171 patients, were identified and considered eligible for analysis (9129 subjects received statin therapy while 2042 patients were part of the respective control arms). Quantitative analysis (5 studies were included) showed that statin use was associated with lower mortality (HR: 0.65; 95% CI: 0.56-0.75, I²: 0%). Also, the meta-analysis showed that statin therapy was associated with a lower incidence of MACE (HR: 0.78; 95% CI: 0.69-0.88, I²:27%).

CONCLUSION

Our data suggest that in a population with MINOCA, the use of statin therapy results in significant reduction on MACE and mortality. These results must be confirmed in future clinical trials.

The association between carotid atherosclerosis and treatment with lithium and antipsychotics in patients with bipolar disorder

OBJECTIVES

Patients with bipolar disorder are at high risk of cardiovascular diseases. Among cardiovascular diseases, coronary heart disease and stroke are the leading causes of premature death and both share the pathogenesis of arterial atherosclerosis. Increased carotid intima-media thickness is sensitive for detecting early atherosclerosis and a practical index for predicting cardiovascular diseases. However, few studies investigated carotid intima-media thickness in adults with bipolar disorder. We attempted to determine the factors associated with carotid intima-media thickness in adults with bipolar disorder.

METHODS

The euthymic out-patients with bipolar I disorder aged over 20 years were recruited to measure the carotid intima-media thickness value through B-mode carotid ultrasound. Those with any psychiatric disorder, acute or life-threatening medical condition were excluded. All clinical information was obtained by reviewing medical records and directly interviewing patients with reliable others.

RESULTS

Of the 106 participants with a mean age of 44.5 years, 40.6% (N = 43) had concurrent cardiovascular/endocrine/metabolic diseases. A multivariate regression indicated that higher assumed daily lithium dosage was significantly associated with a decreased carotid intima-media thickness in the whole sample. In the young subgroup (⩽45 years old, N = 63), higher current daily lithium dosage and lower body mass index were associated with lower carotid intima-media thickness. In those without concurrent cardiovascular/endocrine/metabolic diseases, higher ratio of first-generation antipsychotics exposure in relation to illness chronicity was associated with higher carotid intima-media thickness, after controlling for body mass index or age.

CONCLUSION

Lithium treatment may be associated with less progression in carotid intima-media thickness and the reduced risk for atherosclerosis in adults with bipolar disorder, including those with high cardiovascular disease risk. In addition to age and body mass index, antipsychotics may increase carotid intima-media thickness even in the low cardiovascular disease-risk patients.

Pattern of organ remodeling in chronic non-communicable diseases is due to endogenous regulations and falls under the category of Kauffman's self-organization: A case of arterial neointimal pathology

Clinical diagnosis is based on analysis of pathologic findings that may result in perceived patterns. The same is true for diagnostic pathology: Pattern analysis is a foundation of the histopathology-based diagnostic system and, in conjunction with clinical and laboratory findings, forms a basis for the classification of diseases. Any histopathology diagnosis is based on the explicit assumption that the same diseased condition should result in formation of the same (or highly similar) morphologic patterns in different individuals; it is a standard approach in microscopic pathology, including that of non-communicable chronic diseases with organ remodeling. During fifty years of examining diseased tissues under microscopy, I keep asking the same question: Why is a similarity of patterns expected for chronic organ remodeling? For infection diseases, xenobiotic toxicity and deficiencies forming an identical pathologic pattern in different individuals is understandable and logical: The same infection, xenobiotic, or deficiency strikes the same target, which results in identical pathology. The same is true for Mendelian diseases: The same mutations lead to the same altered gene expressions and the same pathologic pattern. But why does this regularity hold true for chronic diseases with organ remodeling? Presumable causes (or risk factors) for a particular chronic disease differ in magnitude and duration between individuals, which should result in various series of transformations. Yet, mysteriously enough, pathological remodeling in a particular chronic disease always falls into a main dominating pattern, perpetuating and progressing in a similar fashion in different patients. Furthermore, some chronic diseases of different etiologies and dissimilar causes/risk factors manifest as identical or highly similar patterns of pathologic remodeling. HYPOTHESIS: I hypothesize that regulations governing a particular organ's chronic remodeling were selected in evolution as the safest response to various insults and physiologic stress conditions. This hypothesis implies that regulations directing diseased chronic remodeling always preexist but normally are controlled; this control can be disrupted by a diverse range of non-specific signals, liberating the pathway for identical pathologic remodeling. This hypothesis was tested in an analysis of arterial neointimal formation, the identical pathology occurring in different diseases and pathological conditions: graft vascular disease in organ transplantation, in-stent restenosis, peripheral arterial diseases, idiopathic intimal hyperplasia, Kawasaki disease, coronary atherosclerosis and as reaction to drugs. The hypothesis suggests that arterial intimal cells are poised between only two alternative pathways: the pathway with controlled intimal cell proliferation or the pathway where such control is disrupted, ultimately leading to the progressive neointimal pathology. By this property the arterial neointimal formation constitutes a special case of Kauffman's self-organization. This new hypothesis gives a parsimonious explanation for identical pathological patterns of arterial remodeling (neointimal formation), which occurs in diseases of different etiologies and due to dissimilar causes/risk factors, or without any etiology and causes/risk factors at all. This new hypothesis also suggests that regulation facilitating intimal cell proliferation cannot be overwritten or annulled because this feature is vital for arterial differentiation, cell renewal, and integrity. This hypothesis suggests that studying numerous, and likely interchangeable, non-specific signals that disrupt regulation controlling intimal cell proliferation is unproductive; instead, a study of the controlling regulation(s) itself should be a priority of our research.

Effect of dietary supplement from mono-culture fermentation of Moringa oleifera seeds by Rhizopus stolonifer on hematology and markers linked to hypercholesterolemia in rat model

Mono-culture fermentation by Rhizopus stolonifer could promote the healthiness of immune systems and cholesterol levels. Hence, we examined the effect of diet from mono-culture fermentation of Moringa oleifera seeds by R. stolonifer (MCF-MORS) on hematological parameters and fundamental indicators of hypercholesterolemia in rat. The animals were divided into six groups (n = 6). Group 1 was placed on basal diet. Group II, III, IV and V were placed on a basal diets supplemented with 7.5%, 15%, 22.5% and 30%, respectively, of MCF-MORS. Group VI was placed on basal diet fed with unfermented M. oleifera seeds (UF-MOS). The experiment lasted for eight weeks. The results revealed 7.5% MCF-MORS as better biological method to augment PCV, RBC and Hb count in animal model. Also, 7.5% and/or 15% MCF-MORS demonstrated highest levels in centrophils, neutrophils and eosinophils, whereas the levels of lymphocytes, basophils and monocytes showed no significant difference. Similarly, 7.5% and 15% MCF-MORS modulated LDL and HDL, respectively, better than UF-MOS; but showing no difference in cholesterol level. MCF-MORS also maintained architectural integrity of villi and splenocytes better than UF-MOS. We therefore concluded that diet from MCF-MORS at 7.5% and 15% modulates HDL, LDL, cholesterol and immune system-related disorders better than UF-MOS in rat model.

Submaximal angioplasty for symptomatic intracranial atherosclerosis: a prospective Phase I study

OBJECTIVE

Intracranial atherosclerotic disease (ICAD) accounts for approximately 10% of ischemic strokes. The recent Stenting and Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis (SAMMPRIS) study demonstrated a high incidence of perioperative complications (15%) for treatment of ICAD with stenting. Although the incidence of stroke was lower in the medical arm, recurrent stroke was found in 12% of patients despite aggressive medical management, suggesting that intervention may remain a viable option for ICAD if perioperative risk is minimized. Angioplasty without stenting represents an alternative and understudied revascularization treatment for ICAD. Submaximal angioplasty limits the risks of thromboembolism, vessel perforation, and reperfusion hemorrhage that were frequently reported with stenting in the SAMMPRIS trial. The authors conducted a prospective Phase I trial designed to assess the safety of submaximal angioplasty in patients with symptomatic ICAD.

METHODS

This study was approved by the local institutional review board. Demographic and clinical data were prospectively collected. Angioplasty was performed with a balloon undersized to approximately 50%–70% of the nondiseased vessel diameter in patients with symptomatic ICAD who had angiographically significant stenosis of ≥ 70%. The primary outcome measure was the incidence of periprocedural complications (combined rate of death, stroke, and hemorrhage occurring within 30 days and at 1 year).

RESULTS

Among the 65 patients with symptomatic ICAD who were screened, 24 had significant angiographic stenosis that met the inclusion criteria of this study. The mean age was 64.08 years (median 65 years; SD ± 11.24 years), most were men (62.5%), and most were white (66.67%). Many patients had concomitants of vascular disease, including hypertension (95.8%), hyperlipidemia (70.83%), smoking history (54.1%), and diabetes mellitus (50.0%). Coronary artery disease (41.66%) and previous stroke or transient ischemic attack (45.83%) were frequently present. Most patients (75%) had anterior circulation stenosis. The mean preprocedure stenosis was 80.16% (median 80%, range 70%–95%). Submaximal angioplasty was performed in patients who met the inclusion criteria, with a mean postangioplasty stenosis rate of 54.62% (median 55.5%, range 31%–78%). Rates of ischemic stroke in the territory of the treated artery were 0% within 30 days and 5.55% (in the only patient who presented with recurrent stroke) at 1 year. The mortality and hemorrhage rates in this series were 0%.

CONCLUSIONS

This study demonstrates the safety of the submaximal angioplasty technique, with no permanent periprocedural complications in 24 treated patients.

Statin pretreatment is associated with better outcomes in large artery atherosclerotic stroke

OBJECTIVE

Even though statin pretreatment is associated with better functional outcomes and lower risk of mortality in acute ischemic stroke, there are limited data evaluating this association in acute ischemic stroke due to large artery atherosclerosis (LAA), which carries the highest risk of early stroke recurrence.

METHODS

Consecutive patients with acute LAA were prospectively evaluated from 7 tertiary-care stroke centers during a 3-year period. Statin pretreatment, demographics, vascular risk factors, and admission and discharge stroke severity were recorded. The outcome events of interest were neurologic improvement during hospitalization (quantified as the relative decrease in NIH Stroke Scale score at discharge in comparison to hospital admission), favorable functional outcome (FFO) (defined as modified Rankin Scale score of 0-1), recurrent stroke, and death at 1 month. Statistical analyses were performed using univariable and multivariable Cox regression models adjusting for potential confounders. All analyses were repeated following propensity score matching.

RESULTS

Statin pretreatment was documented in 192 (37.2%) of 516 consecutive patients with LAA (mean age: 65 ± 13 years; 60.8% men; median NIH Stroke Scale score: 9 points, interquartile range: 5-18). Statin pretreatment was associated with greater neurologic improvement during hospitalization and higher rates of 30-day FFO in unmatched and matched (odds ratio for FFO: 2.44; 95% confidence interval [CI]: 1.07-5.53) analyses. It was also related to lower risk of 1-month mortality and stroke recurrence in unmatched and matched analyses (hazard ratio for recurrent stroke: 0.11, 95% CI: 0.02-0.46; hazard ratio for death: 0.24, 95% CI: 0.08-0.75).

CONCLUSION

Statin pretreatment in patients with acute LAA appears to be associated with better early outcomes regarding neurologic improvement, disability, survival, and stroke recurrence.

Long-term exposure to traffic-related air pollution and progression of carotid artery atherosclerosis: a prospective cohort study

OBJECTIVES

Epidemiological studies have demonstrated associations between long-term exposure to traffic-related air pollution and coronary heart disease (CHD). Atherosclerosis is the principal pathological process responsible for CHD events, but effects of traffic-related air pollution on progression of atherosclerosis are not clear. This study aimed to investigate associations between long-term exposure to traffic-related air pollution and progression of carotid artery atherosclerosis.

SETTING

Healthy volunteers in metropolitan Vancouver, Canada.

PARTICIPANTS AND OUTCOME MEASURES

509 participants aged 30-65 years were recruited and followed for approximately 5 years. At baseline and end of follow-up, participants underwent carotid artery ultrasound examinations to assess atherosclerosis severity, including carotid intima-media thickness, plaque area, plaque number and total area. Annual change of each atherosclerosis marker during the follow-up period was calculated as the difference between these two measurements divided by years of follow-up. Living close to major roads was defined as ≤150 m from a highway or ≤50 m from a major road. Residential exposures to traffic-related air pollutants including black carbon, fine particles, nitrogen dioxide and nitric oxide were estimated using high-resolution land-use regression models. The data were analysed using general linear models adjusting for various covariates.

RESULTS

At baseline, there were no significant differences in any atherosclerosis markers between participants living close to and those living away from major roads. After follow-up, the differences in annual changes of these markers between these two groups were small and not statistically significant. Also, no significant associations were observed with concentrations of traffic-related air pollutants including black carbon, fine particles, nitrogen dioxide and nitric oxide.

CONCLUSIONS

This study did not find significant associations between traffic-related air pollution and progression of carotid artery atherosclerosis in a region with lower levels and smaller contrasts of ambient air pollution.

Hyperglycemia impairs atherosclerosis regression in mice

Diabetic patients are known to be more susceptible to atherosclerosis and its associated cardiovascular complications. However, the effects of hyperglycemia on atherosclerosis regression remain unclear. We hypothesized that hyperglycemia impairs atherosclerosis regression by modulating the biological function of lesional macrophages. HypoE (Apoe(h/h)Mx1-Cre) mice express low levels of apolipoprotein E (apoE) and develop atherosclerosis when fed a high-fat diet. Atherosclerosis regression occurs in these mice upon plasma lipid lowering induced by a change in diet and the restoration of apoE expression. We examined the morphological characteristics of regressed lesions and assessed the biological function of lesional macrophages isolated with laser-capture microdissection in euglycemic and hyperglycemic HypoE mice. Hyperglycemia induced by streptozotocin treatment impaired lesion size reduction (36% versus 14%) and lipid loss (38% versus 26%) after the reversal of hyperlipidemia. However, decreases in lesional macrophage content and remodeling in both groups of mice were similar. Gene expression analysis revealed that hyperglycemia impaired cholesterol transport by modulating ATP-binding cassette A1, ATP-binding cassette G1, scavenger receptor class B family member (CD36), scavenger receptor class B1, and wound healing pathways in lesional macrophages during atherosclerosis regression. Hyperglycemia impairs both reduction in size and loss of lipids from atherosclerotic lesions upon plasma lipid lowering without significantly affecting the remodeling of the vascular wall.

Poor maternal nutrition programmes a pro-atherosclerotic phenotype in ApoE-/- mice

Numerous animal studies have consistently shown that early life exposure to LP (low-protein) diet programmes risk factors for CVD (cardiovascular disease) such as dyslipidaemia, high BP (blood pressure) and cardiac dysfunction in the offspring. However, studies on the effect of maternal under-nutrition on offspring development of atherosclerosis are scarce. Applying our LP model to the ApoE(-/-) atherosclerosis-prone mouse model, we investigated the development of atherosclerotic lesions in the aortic root of 6-month-old offspring. In addition, markers of plaque progression including SMA (smooth muscle actin) and Mac3 (macrophage marker 3) were studied. Pregnant dams were fed on a control (20% protein) or on an isocaloric LP diet (8% protein) throughout pregnancy and lactation. After weaning, male offspring were maintained on 20% normal laboratory chow. At 6 months of age, LP offspring showed a significantly greater plaque area (P<0.05) with increased cholesterol clefts and significantly higher indices of DNA damage compared with controls (P<0.05). The expression of HMG-CoA reductase (3-hydroxy-3-methyl-glutaryl-CoA reductase) (P<0.05) and LDL (low-density lipoprotein) receptor in the liver of LP offspring were increased. Furthermore, LP offspring had higher LDL-cholesterol levels (P<0.05) and a trend towards elevated insulin. There were no differences in other lipid measurements and fasting glucose between groups. These observations suggest that early exposure to an LP diet accelerates the development and increases the progression of atherosclerotic lesions in young adult offspring. Future studies are needed to elucidate the specific mechanisms linking in utero exposure to a diet low in protein to the development of atherosclerosis.

Neovascularization of coronary tunica intima (DIT) is the cause of coronary atherosclerosis. Lipoproteins invade coronary intima via neovascularization from adventitial vasa vasorum, but not from the arterial lumen: a hypothesis

BACKGROUND

An accepted hypothesis states that coronary atherosclerosis (CA) is initiated by endothelial dysfunction due to inflammation and high levels of LDL-C, followed by deposition of lipids and macrophages from the luminal blood into the arterial intima, resulting in plaque formation. The success of statins in preventing CA promised much for extended protection and effective therapeutics. However, stalled progress in pharmaceutical treatment gives a good reason to review logical properties of the hypothesis underlining our efforts, and to reconsider whether our perception of CA is consistent with facts about the normal and diseased coronary artery.

ANALYSIS

To begin with, it must be noted that the normal coronary intima is not a single-layer endothelium covering a thin acellular compartment, as claimed in most publications, but always appears as a multi-layer cellular compartment, or diffuse intimal thickening (DIT), in which cells are arranged in many layers. If low density lipoprotein cholesterol (LDL-C) invades the DIT from the coronary lumen, the initial depositions ought to be most proximal to blood, i.e. in the inner DIT. The facts show that the opposite is true, and lipids are initially deposited in the outer DIT. This contradiction is resolved by observing that the normal DIT is always avascular, receiving nutrients by diffusion from the lumen, whereas in CA the outer DIT is always neovascularized from adventitial vasa vasorum. The proteoglycan biglycan, confined to the outer DIT in both normal and diseased coronary arteries, has high binding capacity for LDL-C. However, the normal DIT is avascular and biglycan-LDL-C interactions are prevented by diffusion distance and LDL-C size (20 nm), whereas in CA, biglycan in the outer DIT can extract lipoproteins by direct contact with the blood. These facts lead to the single simplest explanation of all observations: (1) lipid deposition is initially localized in the outer DIT; (2) CA often develops at high blood LDL-C levels; (3) apparent CA can develop at lowered blood LDL-C levels. This mechanism is not unique to the coronary artery: for instance, the normally avascular cornea accumulates lipoproteins after neovascularization, resulting in lipid keratopathy.

HYPOTHESIS

Neovascularization of the normally avascular coronary DIT by permeable vasculature from the adventitial vasa vasorum is the cause of LDL deposition and CA. DIT enlargement, seen in early CA and aging, causes hypoxia of the outer DIT and induces neovascularization. According to this alternative proposal, coronary atherosclerosis is not related to inflammation and can occur in individuals with normal circulating levels of LDL, consistent with research findings.

Arterial pathology in canine mucopolysaccharidosis-I and response to therapy

Mucopolysaccharidosis-I (MPS-I) is an inherited deficiency of α-L-iduronidase (IdU) that causes lysosomal accumulation of glycosaminoglycans (GAG) in a variety of parenchymal cell types and connective tissues. The fundamental link between genetic mutation and tissue GAG accumulation is clear, but relatively little attention has been given to the morphology or pathogenesis of associated lesions, particularly those affecting the vascular system. The terminal parietal branches of the abdominal aorta were examined from a colony of dogs homozygous (MPS-I affected) or heterozygous (unaffected carrier) for an IdU mutation that eliminated all enzyme activity, and in affected animals treated with human recombinant IdU. High-resolution computed tomography showed that vascular wall thickenings occurred in affected animals near branch points, and associated with low endothelial shear stress. Histologically these asymmetric 'plaques' entailed extensive intimal thickening with disruption of the internal elastic lamina, occluding more than 50% of the vascular lumen in some cases. Immunohistochemistry was used to show that areas of sclerosis contained foamy (GAG laden) macrophages, fibroblasts and smooth muscle cells, with loss of overlying endothelial basement membrane and claudin-5 expression. Lesions contained scattered cells expressing nuclear factor-κβ (p65), increased fibronectin and transforming growth factor β-1 signaling (with nuclear Smad3 accumulation) in comparison to unaffected vessels. Intimal lesion development and morphology was improved by intravenous recombinant enzyme treatment, particularly with immune tolerance to this exogenous protein. The progressive sclerotic vasculopathy of MPS-I shares some morphological and molecular similarities to atherosclerosis, including formation in areas of low shear stress near branch points, and can be reduced or inhibited by intravenous administration of recombinant IdU.