Acute myocardial infarction in patients with versus without aortic valve sclerosis and effect of statin therapy (from the Heart and Soul Study)

Association between Circulating Omentin-1 Levels and Aortic Valve Sclerosis

BACKGROUND

Aortic valve sclerosis (AVS) is characterized by thickening of the valve leaflets accompanied by increased echogenicity and calcification without significant limitations in valve movements. Omentin-1 is a glycoprotein of the adiponectin family released from visceral adipose tissue, and it can be used as a biomarker of atherosclerosis, obesity, and metabolic syndrome. No studies have demonstrated any relationship between AVS and omentin-1 in the literature. We aimed to explore the association of serum omentin-1 levels with AVS.

METHODS

Eighty-six patients with AVS and 92 age- and sex-matched controls were enrolled into the study. The baseline clinical characteristics of the patients were recorded. Conventional 2-dimensional echocardiography was performed. Omentin-1 levels were measured.

RESULTS

The mean omentin-1 level was significantly lower in the AVS (+) group compared to the control group (78.16 ± 44.95 vs. 163.57 ± 59.84 ng/mL, p < 0.001). Omentin-1 [odds ratio (OR) = 3.45, 95% confidence interval (CI) = 1.88-5.39, p < 0.001,] and LDL-C (OR = 1.82, 95% CI = 1.33-2.16, p = 0.015) were found to be independent predictors of AVS in multivariate logistic regression analysis. An omentin-1 level of < 92.45 ng/mL had 90.5% sensitivity and 71.4% specificity for the prediction of AVS (area under curve: 0.697, p < 0.001).

CONCLUSIONS

Our results indicated that a lower omentin-1 level was associated with an increased risk of AVS. We suggest that omentin-1 could be used as a treatment target as well as to predict AVS.

Aortic Valve Sclerosis in High-Risk Coronary Artery Disease Patients

Background: Current knowledge regarding the relationship between aortic valve sclerosis (AVSc), cardiovascular risk factors, and mortality in patients with known coronary artery disease (CAD) is still unclear. The present study aimed at investigating the prevalence of AVSc as well as its association with long-term all-cause mortality in high-risk CAD patients that has never been explored in large cohorts thus far.

Methods and Results: In this retrospective and observational cohort study we enrolled high-risk CAD patients, hospitalized at Centro Cardiologico Monzino (CCM), Milan, Italy, between January 2006 and December 2016. The morphology and function of the aortic valve were assessed from the recorded echocardiographic images to evaluate the presence of AVSc, defined as a non-uniform thickening of the aortic leaflets with no consequences on hemodynamics. Data on 5-year all-cause mortality was retrieved from a Regional database. Of the 5,489 patients initially screened, 4,938 (mean age 67 ± 11 years, 3,954 [80%] men) were enrolled in the study. In the overall population, AVSc was detected in 2,138 (43%) patients. Multivariable LASSO regression revealed that age, female gender, diabetes mellitus, previous MI, and left ventricular ejection fraction were independently associated with AVSc. All-cause mortality (adjusted hazard ratio: 1.29, 95%CI: 1.05–1.58) was significantly higher in AVSc than in non-AVSc patients.

Conclusions: AVSc is frequently detected in high-risk CAD patients and is associated with long-term mortality. Our findings corroborate the hypothesis that AVSc is an underestimated marker of systemic cardiovascular risk. Thus, AVSc detection may be used to improve long-term risk stratification of high-risk CAD patients.

Are there any subclinical myocardial dysfunctions in subjects with aortic valve sclerosis? A 3D-speckle tracking echocardiography study

Aortic valve sclerosis (AVS) is defined as calcified and thickened aortic leaflets without restriction of leaflet motion. We have not found any studies that previously assessed the effect of AVS on myocardial functions with three dimensional-speckle tracking echocardiography (3D-STE). Therefore, we aimed to identify any early changes in left atrial (LA) myocardial dynamics and/or left ventricular (LV) systolic functions in patients with AVS using 3D-STE. Seventy-five patients with AVS and 80 age- and gender-matched controls were enrolled into the study. The baseline clinical characteristics of the study patients were recorded. Conventional 2D echocardiographic and 3D-STE analyses were performed. The LV-global longitudinal strain (LV-GLS) and LV-global circumferential strain (LV-GCS) were significantly decreased in the AVS (+) group than in the control group (p < 0.001 and p = 0.013, respectively). In multivariate logistic regression analysis; LV-GLS (p < 0.001, odds ratio (OR) = 3.16, 95% confidence interval (CI) 1.42-5.63) and Triglyceride (TG) (p = 0.033, OR = 1.29, 95% CI 1.11-1.72) were found to be independent predictors of AVS. ROC analysis was performed to find out the ideal LV-GLS cut-off value for predicting the AVS. A LV-GLS value of > - 18 has 85.8% sensitivity, 67.5% specificity for the prediction of the AVS. Our results support that subjects with AVS may have subclinical LV deformation abnormalities even though they have not LV pressure overload. According to our findings, patients with AVS should be investigated in terms of atherosclerotic risk factors, their dysmetabolic status should be evaluated and closely followed up for their progression to calcific aortic stenosis.

An echocardiographic predictor of contrast-induced nephropathy following percutaneous coronary intervention in acute coronary syndrome: aortic valve sclerosis

Objective. Aortic valve sclerosis (AVS) is closely related to endothelial dysfunction. The association of AVS with contrast-induced nephropathy (CIN) is unknown. We planned to investigate the relationship of AVS besides known parameters with CIN. Design. Baseline characteristics, biochemical values, and AVS of 292 consecutive patients with acute coronary syndrome (ACS) that underwent percutaneous coronary intervention (PCI) were analyzed. Results. Fifty-three patients (18.2%) had CIN. Patients with CIN were older, less likely to be smokers, and had more prevalent prior bypass surgery, higher Mehran score, creatinine, and uric acid concentrations than those without CIN. AVS was more prevalent in patients with CIN. Logistic regression analysis including all related parameters identified Mehran score (OR = 1.036, p = .033), uric acid concentration (OR = 1.244, p = .023), and AVS (OR: 2.223, p = .027) as independent predictors of CIN. Conclusion. AVS is independently associated with CIN in patients with acute coronary syndrome undergoing percutaneous coronary intervention. AVS may help to identify high-risk patients for CIN, who would benefit from preventive measures.

Aortic Valve Sclerosis Adds to Prediction of Short-Term Mortality in Patients with Documented Coronary Atherosclerosis

Aims: Aortic valve sclerosis (AVSc), a non-uniform thickening of leaflets with an unrestricted opening, is characterized by inflammation, lipoprotein deposition, and matrix degradation. In the general population, AVSc predicts long-term cardiovascular mortality (+50%) even after adjustment for vascular risk factors and clinical atherosclerosis. We have hypothesized that AVSc is a risk-multiplier able to predict even short-term mortality. To address this issue, we retrospectively analyzed 90-day mortality of all patients who underwent isolated coronary artery bypass grafting (CABG) at Centro Cardiologico Monzino over a ten-year period (2006–2016). Methods: We analyzed 2246 patients and 90-day all-cause mortality was 1.5% (31 deaths). We selected only patients deceased from cardiac causes (n = 29) and compared to alive patients (n = 2215). A cardiologist classified the aortic valve as no-AVSc (n = 1352) or AVSc (n = 892). Cox linear regression and integrated discrimination improvement (IDI) analyses were used to evaluate AVSc in predicting 90-day mortality. Results: AVSc 90-day survival (97.6%) was lower than in no-AVSc (99.4%; p < 0.0001) with a hazard ratio (HR) of 4.0 (95%CI: 1.78, 9.05; p < 0.0001). The HR for AVSc, adjusted for propensity score, was 2.7 (95%CI: 1.17, 6.23; p = 0.02) and IDI statistics confirmed that AVSc significantly adds (p < 0.001) to the identification of high-risk patients than EuroSCORE II alone. Conclusion: Our data supports the hypothesis that a risk stratification strategy based on AVSc, added to ESII, may allow better recognition of patients at high-risk of short-term mortality after isolated surgical myocardial revascularization. Results from this study warrant further confirmation.

Impact of Oxidative Stress and Protein S-Glutathionylation in Aortic Valve Sclerosis Patients with Overt Atherosclerosis

Aortic valve sclerosis (AVSc) is characterized by non-uniform thickening of the leaflets without hemodynamic changes. Endothelial dysfunction, also caused by dysregulation of glutathione homeostasis expressed as ratio between its reduced (GSH) and its oxidised form (GSSG), could represent one of the pathogenic triggers of AVSc. We prospectively enrolled 58 patients with overt atherosclerosis and requiring coronary artery bypass grafting (CABG). The incidence of AVSc in the studied population was 50%. The two groups (No-AVSc and AVSc) had similar clinical characteristics. Pre-operatively, AVSc group showed significantly lower GSH/GSSG ratio than No-AVSc group (p = 0.02). Asymmetric dimethylarginine (ADMA) concentration was significantly higher in AVSc patients compared to No-AVSc patients (p < 0.0001). Explanted sclerotic aortic valves presented a significantly increased protein glutathionylation (Pr-SSG) than No-AVSc ones (p = 0.01). In vitro, inhibition of glutathione reductase caused β-actin glutathionylation, activation of histone 2AX, upregulation of α2 smooth muscle actin (ACTA2), downregulation of platelet and endothelial cell adhesion molecule 1 (PECAM1) and cadherin 5 (CDH5). In this study, we showed for the first time that the dysregulation of glutathione homeostasis is associated with AVSc. We found that Pr-SSG is increased in AVSc leaflets and it could lead to EndMT via DNA damage. Further studies are warranted to elucidate the causal role of Pr-SSG in aortic valve degeneration.

Association of Aortic Valve Sclerosis and Clinical Factors in Patients With Acute Myocardial Infarction

BACKGROUND

Since aortic valve sclerosis (AVS) and coronary artery disease (CAD) share similar cardiovascular risk factors, we hypothesized that the clinical profile of patients with acute myocardial infarction (AMI) would be worse in the presence of AVS. The aim of this study was to investigate the association between AVS and clinical factors in patients with AMI.

METHODS

Three hundred and fifteen patients with AMI were consecutively enrolled in the study. Echocardiography was used to assess the aortic valve morphology and left ventricular function. The extent and severity of CAD were assessed by Gensini score and the number of obstructed vessels. The patients were divided into 2 groups according to presence or absence of AVS.

RESULTS

The overall number of patients with AVS was 132 (41.9%). Patients with AVS were older (69.5 ± 11 vs. 59.5 ± 12 years, P < 0.00001). They also had a higher prevalence of hypertension (61% vs. 45%, P = 0.006), prior CAD (33% vs. 23%, P = 0.041), prior AMI (20% vs. 11%, P = 0.019) and a higher percentage were female (32% vs. 19%, P = 0.007) compared with AMI patients without AVS. There was no significant difference between the 2 groups with respect to the Gensini score (P = 0.372). Prior AMI was associated with AVS on age-adjusted logistic regression analyses. A multivariate analysis showed an independent association between the AVS and prior AMI and age (P < 0.0000001, P = 0.022, respectively).

CONCLUSIONS

Our results showed that the presence of AVS is associated with AMI recurrence.

Cardiovascular morbidity and mortality in patients with aortic valve sclerosis: A systematic review and meta-analysis

AIMS

The association between aortic valve sclerosis (AVSc) and cardiovascular (CV) events is not consistent among different studies. We have performed a meta-analysis evaluating the association between AVSc and fatal and/or non-fatal CV and cerebrovascular events.

METHODS AND RESULTS

A systematic search was performed in the electronic databases (PubMed, Web of Science, Scopus, EMBASE). Studies evaluating coronary artery disease (CAD), stroke and CV mortality in AVSc patients and controls were included. Differences among cases and controls were expressed as Odds Ratio (OR) with pertinent 95% Confidence Intervals (CI). Thirty-one studies on 10,537 AVSc patients and 25,005 controls were included in the final analysis. The absolute risk of CAD was 45.8% (95% CI: 32.9-59.3) in AVSc patients and 29.4% (95% CI: 21.8-38.5) in controls with an OR of 2.02 (95% CI: 1.67-2.44) and an attributable risk of 35.8%. Moreover, stroke was reported in 11.8% (95% CI: 4.4-27.7) of AVSc patients and 7.9% (95% CI: 2.5-22.7) of controls (OR: 1.41, 95% CI: 1.16-1.71) with an attributable risk of 33.0%. CV mortality was 6.2% (95% CI: 2.7-13.5) in AVSc patients and 2.0% (95% CI: 0.5-7.9) in controls (OR: 2.70, 95% CI: 1.45-5.01), with an attributable risk of 67.7%. Results were confirmed when pooling together ORs for CAD, stroke and CV mortality obtained by means of multivariate analysis.

CONCLUSIONS

AVSc is associated with CAD, stroke and CV mortality. Taken together, these data suggest that patients with AVSc may benefit from a stricter CV risk monitoring and that AVSc screening may be included in the frame of CV risk stratification protocols.

Usefulness of an Echocardiographic Composite Cardiac Calcium Score to Predict Death in Patients With Stable Coronary Artery Disease (from the Heart and Soul Study)

Mitral annular calcium and aortic valve sclerosis on transthoracic echocardiography (TTE) are independently associated with cardiovascular (CV) events in patients with coronary artery disease (CAD). However, the prognostic value of calcific deposits at multiple sites is unknown. We performed TTEs in a prospective cohort of 595 outpatients with stable CAD and graded the severity of calcific deposition at 6 sites: mitral annulus, aortic valve, aortic ring, sinotubular junction, papillary muscle tip, and left main coronary artery. For each site with moderate calcific deposition or greater, 1 point was given to generate a composite cardiac calcium score (maximum of 6). The primary end point was the occurrence of CV events-a composite of death, myocardial infarction, stroke, transient ischemic attack, and heart failure. The association of the composite calcium score with CV events was evaluated using multivariate Cox proportional hazards models. Over a median follow-up of 4.2 years, 205 CV events occurred. Participants with a composite calcium score ≥2 had a higher risk of CV events (11.1 events/100 person-years) than those with a score of 0 (5.5 events/100 person-years, unadjusted hazard ratio [HR] 2.01, p <0.001), but this association was not significant after multivariate adjustment. The risk of death was higher in participants with a composite calcium score of ≥2 (8.9 events/100 person-years) versus those with a score of 0 (3.6 events/100 person-years, unadjusted HR 2.51, p <0.001). After adjustment for age, diabetes mellitus, previous coronary revascularization, diastolic blood pressure, estimated glomerular filtration rate, and serum phosphorus level, the risk of death remained higher in participants with a composite calcium score of ≥2 compared with those with a score of 0 (adjusted HR 1.76, 95% confidence interval 1.10 to 2.81, p = 0.02). In conclusion, a simple TTE-derived composite cardiac calcium score was independently predictive of death in patients with pre-existing CAD.

Link between aortic valve sclerosis and myocardial no-reflow in ST-segment elevation myocardial infarction

OBJECTIVE

The"no-reflow" phenomenon is associated with a worse prognosis at follow-up for patients with acute ST-segment elevation myocardial infarction (STEMI). Predicting and preventing no-reflow is therefore a crucial step in improving the prognosis of STEMI patients. The purpose of this study was to investigate the association between aortic valve sclerosis (AVS) and myocardial no-reflow in patients with STEMI.

PATIENTS AND METHODS

Patients with a first-time diagnosis of STEMI were enrolled consecutively. No-reflow was defined as a final TIMI 3 flow with a myocardial blush of grade < 2, temporary epicardial coronary no-reflow, and distal coronary occlusion. AVS was defined by echocardiography as thickening and calcification of the normal trileaflet aortic valve without obstruction to the left ventricular outflow.

RESULTS

No-reflow developed in 41 patients. In univariate analysis, age, male gender, smoking, culprit lesion Syntax score (SX score), and hypertension were significantly associated with no-reflow. Multivariate binary logistic regression analyses demonstrated age [95 % confidence interval (CI), 1.024-1.096; p=0.001), AVS (95 % CI, 1.002-1.100; p=0.039], culprit lesion SX score (95 % CI, 1.08-1.021 p=0.008), and symptom-to-balloon time (95 % CI, 1.020-1.097; p=0.002) as independent determinants of myocardial no-reflow.

CONCLUSION

AVS was significantly and independently associated with myocardial no-reflow in STEMI patients.

Mitral and aortic valve sclerosis/calcification and carotid atherosclerosis: results from 1065 patients

This study assesses whether aortic valve sclerosis (AVS) and mitral annulus calcification (MAC) are associated with carotid artery atherosclerosis, independently of traditional cardiovascular risk factors. A total of 1065 patients underwent both echocardiography and carotid artery ultrasound scanning. AVS and MAC were defined as focal areas of increased echogenicity and thickening of the aortic leaflets or mitral valve annulus. Carotid artery atherosclerosis was defined as presence/absence of any atherosclerotic plaque or presence/absence of plaque >50 %. Of 1065 patients (65 ± 9 years; 38 % female) who comprised the study population, 642 (60 %) had at least one atherosclerotic plaque. AVS, but not mitral valve sclerosis; was associated with the presence of carotid atherosclerosis (odds ratio (OR) 1.9, 95 % confidence interval (CI) 1.2-3.9; P = 0.005) and the degree of carotid atherosclerosis (OR 2.1, 95 % CI 1.2-3.9; P = 0.01) in a multivariate model including age, gender, previous ischemic heart disease, hypertension, dyslipidemia, smoking, diabetes, family cardiovascular history, left ventricular size, mass, and ejection fraction, and left atrial size. AVS is a significant predictor of carotid atherosclerosis, independently of other cardiovascular clinical and echocardiographic risk factors.

Calcific aortic valve damage as a risk factor for cardiovascular events

Aortic valve calcification (AVC) is a common disease of the elderly. It is a progressive disease ranging from mild valve thickening to severe calcification with aortic valve stenosis. Risk factors for AVC are similar to those for atherosclerosis: age, gender, hypercholesterolemia, diabetes, hypertension, smoking and renal failure. AVC shares many similarities to atherosclerosis, including inflammatory cells and calcium deposits, and correlates with coronary plaque burden. Presence of AVC is associated with increased risk of adverse cardiovascular events. The objective for this review is to discuss the clinical features, natural history and prognostic significance of aortic valve calcifications, including mechanical and hemodynamic factors of flow distribution.

Aortic and mitral annular calcifications are predictive of all-cause and cardiovascular mortality in patients with type 2 diabetes

OBJECTIVE

To examine the association of aortic valve sclerosis (AVS) and mitral annulus calcification (MAC) with all-cause and cardiovascular mortality in type 2 diabetic individuals.

RESEARCH DESIGN AND METHODS

We retrospectively analyzed the data from 902 type 2 diabetic outpatients, who had undergone a transthoracic echocardiography for clinical reasons during the years 1992-2007. AVS and MAC were diagnosed by echocardiography, and a heart valve calcium (HVC) score was calculated by summing up the AVS and MAC variables. The study outcomes were all-cause and cardiovascular mortality.

RESULTS

At baseline, 477 (52.9%) patients had no heart valves affected (HVC-0), 304 (33.7%) had one valve affected (HVC-1), and 121 (13.4%) had both valves affected (HVC-2). During a mean follow-up of 9 years, 137 (15.2%) patients died, 78 of them from cardiovascular causes. Compared with patients with HVC-0, those with HVC-2 had the highest risk of all-cause and cardiovascular mortality, whereas those with HVC-1 had an intermediate risk (P < 0.0001 by the log-rank test). After adjustment for sex, age, BMI, systolic blood pressure, diabetes duration, A1C, LDL cholesterol, estimated glomerular filtration rate, smoking, history of myocardial infarction, and use of antihypertensive and lipid-lowering drugs, the hazard ratio of all-cause mortality was 2.3 (95% CI 1.1-4.9; P < 0.01) for patients with HVC-1 and 9.3 (3.9-17.4; P < 0.001) for those with HVC-2. Similar results were found for cardiovascular mortality.

CONCLUSIONS

Our findings indicate that AVS and MAC, singly or in combination, are independently associated with all-cause and cardiovascular mortality in type 2 diabetic patients.

Association between aortic valve calcification and myocardial ischemia, especially in asymptomatic patients

Aortic valve calcification (AVC) is recognized as a manifestation of systemic arteriosclerosis. However, it is unclear whether AVC is associated with myocardial ischemia. Stress myocardial perfusion SPECT (MPS) is widely used for the diagnosis of myocardial ischemia. However, routine MPS is not recommended, particularly in asymptomatic patients. Accordingly, we investigated the hypothesis that the presence of AVC is strongly associated with inducible myocardial ischemia, even among asymptomatic patients.

METHODS

We investigated 669 consecutive patients who underwent both adenosine stress (201)Tl MPS and echocardiography. We evaluated the extent and severity of myocardial ischemia by the summed difference score (SDS). We defined the presence of myocardial ischemia as SDS ≥ 3 and moderate to severe ischemia as SDS ≥ 8. We classified the severity of AVC according to the number of affected aortic leaflets. We also compared the mean SDS and the prevalence of SDS ≥ 3 and SDS ≥ 8 among patients stratified by the severity of AVC.

RESULTS

The presence of AVC was significantly associated with myocardial ischemia (odds ratio [OR], 1.56; 95% confidence interval [CI], 1.10-2.23; P = 0.013) and moderate to severe ischemia (OR, 2.16; 95% CI, 1.26-3.80; P = 0.0061). In 311 asymptomatic patients, AVC was strongly associated with moderate to severe ischemia (OR, 4.31; 95% CI, 1.67-12.8; P = 0.0043). However, the SDS value and the prevalence of SDS ≥ 3 and SDS ≥ 8 did not increase with increasing number of affected aortic leaflets.

CONCLUSION

The presence of AVC may be associated with the presence of myocardial ischemia, particularly in asymptomatic patients. However, we found no association between the extent of AVC and inducible myocardial ischemia. The presence of AVC may be a useful anatomic marker to help identify patients at high risk of myocardial ischemia, particularly asymptomatic patients.

Impact of chronic kidney disease on the presence and severity of aortic stenosis in patients at high risk for coronary artery disease

OBJECTIVE

We evaluated the impact of chronic kidney disease (CKD) on the presence and severity of aortic stenosis (AS) in patients at high risk for coronary artery disease (CAD).

METHODS

One hundred and twenty consecutive patients who underwent invasive coronary angiography were enrolled. Aortic valve area (AVA) was calculated by the continuity equation using transthoracic echocardiography, and was normalized by body surface area (AVA index).

RESULTS

Among all 120 patients, 78% had CAD, 55% had CKD (stage 3: 81%; stage 4: 19%), and 34% had AS (AVA < 2.0 cm²). Patients with AS were older, more often female, and had a higher frequency of CKD than those without AS, but the prevalence of CAD and most other coexisting conventional risk factors was similar between patients with and without AS. Multivariate linear regression analysis indicated that only CKD and CAD were independent determinants of AVA index with standardized coefficients of -0.37 and -0.28, respectively. When patients were divided into 3 groups (group 1: absence of CKD and CAD, n = 16; group 2: presence of either CKD or CAD, n = 51; and group 3: presence of both CKD and CAD, n = 53), group 3 had the smallest AVA index (1.19 ± 0.30*# cm²/m², *p < 0.05 vs. group 1: 1.65 ± 0.32 cm²/m², and #p < 0.05 vs. group 2: 1.43 ± 0.29* cm²/m²) and the highest peak velocity across the aortic valve (1.53 ± 0.41*# m/sec; *p < 0.05 vs. group 1: 1.28 ± 0.29 m/sec, and #p < 0.05 vs. group 2: 1.35 ± 0.27 m/sec).

CONCLUSION

CKD, even pre-stage 5 CKD, has a more powerful impact on the presence and severity of AS than other conventional risk factors for atherosclerosis in patients at high risk for CAD.

Aortic valve sclerosis and clinical outcomes: moving toward a definition

The presence of aortic valve sclerosis has been suggested as a marker of increased cardiovascular risk, including increased mortality. However, it remains unclear whether aortic valve sclerosis is independently associated with risk or merely a marker of coexistent cardiovascular risk factors. Aortic valve sclerosis is usually diagnosed on transthoracic echocardiography, the most widely used imaging modality in observational and natural history studies of aortic valve disease. Defining aortic valve sclerosis has remained challenging due to the variable and qualitative nature of its description by ultrasound techniques. Importantly, artifacts common to ultrasound imaging and awareness of demographic and clinical history information may bias the diagnosis of aortic valve sclerosis. Because clinicians may alter treatment recommendations or follow-up based on echocardiographic reporting of aortic valve sclerosis, highlighting pitfalls of the subjective nature by which aortic valve sclerosis is identified and establishing diagnostic criteria are necessary. This review describes the diagnostic criteria for aortic valve sclerosis used in outcome studies, summarizes the epidemiological findings reporting the relationship between aortic valve sclerosis and clinical outcome, and proposes a definition of aortic valve sclerosis based on the literature.

Aortic sclerosis, aortic stenosis and lipid-lowering therapy

Calcific aortic stenosis (AS) is a progressive disease that has, until recently, been considered to be a degenerative and unmodifiable process induced by long-lasting mechanical stress. However, histopathologic studies have now demonstrated that the development and progression of calcific AS is based on an active process, sharing a number of similarities with atherosclerosis. Inflammation, lipid infiltration, dystrophic calcification, ossification, platelet deposition and endothelial dysfunction have been observed in both diseases. In addition, several studies have suggested that AS and atherosclerosis share a number of risk factors, such as hypercholesterolemia, elevated lipoprotein (a), smoking, hypertension and diabetes. These findings suggest that statin therapy could be beneficial in AS by its lipid-lowering and/or anti-inflammatory effects, as is the case in atherosclerosis. Although this concept has been supported by experimental work and by four retrospective clinical studies observing significantly slower rates of hemodynamic progression in statin-treated patients, a prospective randomized trial (Scottish Aortic Stenosis and Lipid Lowering Trial, Impact on Regression [SALTIRE]; 80mg of atorvastatin vs placebo) yielded a negative result. In contrast to the retrospective analyses, according to the study protocol, patients with hyperlipidemia had to be excluded in this trial. A recent prospective study (Rosuvastatin Affecting Aortic Valve Endothelium [RAAVE]) treating hypercholesteremic patients with rosuvastatin, found a significantly slower rate of progression in these patients compared with patients with normal cholesterol levels who were left untreated, suggesting that statin therapy may only be beneficial in patients with hyperlipidemia. Lipid-lowering therapy with statins can, therefore, currently only be recommended in this subgroup of patients with AS.

Olfactory ensheathing cells promote neurite sprouting of injured axons in vitro by direct cellular contact and secretion of soluble factors

Olfactory ensheathing cells (OECs) represent an exciting possibility for promoting axonal regeneration within the injured spinal cord. A number of studies have indicated the ability of these cells to promote significant reactive sprouting of injured axons within the injured spinal cord, and in some cases restoration of functional abilities. However, the cellular and/or molecular mechanisms OECs use to achieve this are unclear. To investigate such mechanisms, we report for the first time the ability of OECs to promote post-injury neurite sprouting in an in vitro model of axonal injury. Using this model, we were able to differentiate between the direct and indirect mechanisms underlying the ability of OECs to promote neuronal recovery from injury. We noted that OECs appeared to act as a physical substrate for the growth of post-injury neurite sprouts. We also found that while post-injury sprouting was promoted most when OECs were allowed to directly contact injured neurons, physical separation using tissue culture inserts (1 mm pore size, permeable to diffusible factors but not cells) did not completely block the promoting properties of OECs, suggesting that they also secrete soluble factors which aid post-injury neurite sprouting. Furthermore, this in vitro model allowed direct observation of the cellular interactions between OECs and sprouting neurites using live-cell-imaging techniques. In summary, we found that OECs separately promote neurite sprouting by providing a physical substrate for growth and through the expression of soluble factors. Our findings provide new insight into the ability of OECs to promote axonal regeneration, and also indicate potential targets for manipulation of these cells to enhance their restorative ability.