Apolipoprotein A-I proteolysis in aortic valve stenosis: role of cathepsin S.

Aortic valve stenosis (AVS) is the most common valvular heart disease in the Western world. Therapy based on apolipoprotein A-I (apoA-I), the major protein component of high-density lipoproteins, results in AVS regression in experimental models. Nevertheless, apoA-I degradation by proteases might lead to suboptimal efficacy of such therapy. An activatable probe using a quenched fluorescently labeled full-length apoA-I protein was generated to assess apoA-I-degrading protease activity in plasma derived from 44 men and 20 women with severe AVS (age 65.0 ± 10.4 years) as well as from a rabbit model of AVS. In human and rabbit AVS plasma, apoA-I-degrading protease activity was significantly higher than in controls (humans: 0.038 ± 0.009 vs 0.022 ± 0.005 RFU/s, p < 0.0001; rabbits: 0.033 ± 0.016 vs 0.017 ± 0.005 RFU/s, p = 0.041). Through the use of protease inhibitors, we identified metalloproteinases (MMP) as exerting the most potent proteolytic effect on apoA-I in AVS rabbits (67%, p < 0.05 vs control), while the cysteine protease cathepsin S accounted for 54.2% of apoA-I degradation in human plasma (p < 0.05 vs control) with the maximum effect seen in women (68.8%, p < 0.05 vs men). Accordingly, cathepsin S activity correlated significantly with mean transaortic pressure gradient in women (r = 0.5, p = 0.04) but not in men (r = - 0.09, p = 0.60), and was a significant independent predictor of disease severity in women (standardized beta coefficient 0.832, p < 0.001) when tested in a linear regression analysis. ApoA-I proteolysis is increased in AVS. Targeting circulating cathepsin S may lead to new therapies for human aortic valve disease.

Beneficial Effects of High-Density Lipoproteins on Acquired von Willebrand Syndrome in Aortic Valve Stenosis.

BACKGROUND: Infusions of apolipoprotein A-I (apoA-I), the major protein component of high-density lipoproteins (HDL), result in aortic valve stenosis (AVS) regression in experimental models. Severe AVS can be complicated by acquired von Willebrand syndrome, a haemorrhagic disorder associated with loss of high-molecular-weight von Willebrand factor (vWF) multimers (HMWM), the latter being a consequence of increased shear stress and enhanced vWF-cleaving protease (ADAMTS-13) activity. Although antithrombotic actions of HDL have been described, its effects on ADAMTS-13 and vWF in AVS are unknown. METHODS AND RESULTS: We assessed ADAMTS-13 activity in plasma derived from a rabbit model of AVS (n = 29) as well as in plasma collected from 64 patients with severe AVS (age 65.0 ± 10.4 years, 44 males) undergoing aortic valve replacement (AVR). In both human and rabbit AVS plasma, ADAMTS-13 activity was higher than that in controls (p < 0.05). Accordingly, AVS patients had less HMWM than controls (66.3 ± 27.2% vs. 97.2 ± 24.1%, p < 0.0001). Both ADAMTS-13 activity and HMWM correlated significantly with aortic transvalvular gradients, thereby showing opposing correlations (r = 0.3, p = 0.018 and r = -0.4, p = 0.003, respectively). Administration of an apoA-I mimetic peptide reduced ADAMTS-13 activity in AVS rabbits as compared with the placebo group (2.0 ± 0.5 RFU/sec vs. 3.8 ± 0.4 RFU/sec, p < 0.05). Similarly, a negative correlation was found between ADAMTS-13 activity and HDL cholesterol levels in patients with AVS (r = -0.3, p = 0.045). CONCLUSION: Our data indicate that HDL levels are associated with reduced ADAMTS-13 activity and increased HMWM. HDL-based therapies may reduce the haematologic abnormalities of the acquired von Willebrand syndrome in AVS.

Morphological and Immunohistochemical Characterization of Canine Osteosarcoma Spheroid Cell Cultures.

Spheroid cell culture emerges as powerful in vitro tool for experimental tumour research. In this study, we established a scaffold-free three-dimensional spheroid system built from canine osteosarcoma (OS) cells (D17). Spheroids (7, 14 and 19 days of cultivation) and monolayer cultures (2 and 7 days of cultivation) were evaluated and compared on light and electron microscopy. Monolayer and spheroid cultures were tested for vimentin, cytokeratin, alkaline phosphatase, osteocalcin and collagen I by means of immunohistochemistry. The spheroid cell culture exhibited a distinct network of collagen I in particular after 19-day cultivation, whereas in monolayer cultures, collagen I was arranged as a lamellar basal structure. Necrotic centres of large spheroids, as observed in 14- and 19-day cultures, were characterized by significant amounts of osteocalcin. Proliferative activity as determined by Ki-67 immunoreactivity showed an even distribution in two-dimensional cultures. In spheroids, proliferation was predominating in the peripheral areas. Metastasis-associated markers ezrin and S100A4 were shown to be continuously expressed in monolayer and spheroid cultures. We conclude that the scaffold-free spheroid system from canine OS cells has the ability to mimic the architecture of the in vivo tumour, in particular cell-cell and cell-matrix interactions.

Gender-Related Differences in Patients Presenting with Suspected Acute Coronary Syndromes: Clinical Presentation, Biomarkers and Diagnosis.

OBJECTIVES: Gender differences in patients presenting with suspected acute coronary syndromes (ACS) have not yet been fully characterized. The aim of this study was to assess gender-related disparities in clinical profiles, biomarkers and diagnoses of patients with suspected ACS. METHODS: This single-centre, prospective cohort study included 377 consecutive patients presenting with suspected ACS to the emergency department. Suspected ACS was defined as a request for conventional troponin T (c-cTnT) measurements on clinical grounds. RESULTS: Women were older than men (p = 0.004), and had a lower prevalence of known coronary artery and peripheral vascular disease (p < 0.05). c-cTnT was positive in 8% of female and in 14% of male patients (p = 0.16), TIMI risk score and cardiac biomarkers including c-cTnT, hs-cTnT, myoglobin, creatine kinase, N-terminal pro-brain natriuretic peptide, myeloid-related protein 8/14 and pregnancy-associated plasma protein A were lower in women (p < 0.05). Women were less frequently diagnosed with ACS (30 vs. 51%), and were not referred for urgent coronary angiography as often as men (p < 0.001). In multivariate analysis, female gender was associated with a lower referral for coronary angiography (HR 0.41, 95% CI 0.23-0.78, p = 0.006). CONCLUSIONS: In patients with suspected ACS, women presented with different biomarker profiles, and were less often diagnosed with ACS and referred to coronary angiography.

[Platelet inhibitors in clinical practice]. / Neue Antiaggregantien - klinische Aspekte.

Despite improvements in the treatment of acute coronary syndromes, cardiovascular disease remains the leading cause of death in Europe and the United States. Antiplatelet agents, such as aspirin and clopidogrel, play an important role in the treatment of those patients. Several new alternatives have been tested in clinical trails and some of them have been approved for routine treatment of patients with ACS in Switzerland and the European Union. The latter include Prasugrel (Efient®) and Ticagrelor (Brilique®). Those substances provide more rapid and consistent platelet inhibition but increase the risk of bleeding in some patient subgroups. Thus, the main challenge is to tailor treatment for each patient by taking into consideration patient characteristics, comorbidities, underlying short- and long-term risk factors, ischemic and bleeding risks, and expected individual responses to different medications. This ambitious new approach will be a challenge for in daily clinical work and may ultimately require prioritization among several treatment alternatives. In this article, we review the new antiplatelet agents being developed as well as their pharmacological characteristics, key interactions and side effects and potential clinical indications in subpopulations.

Coronary computed tomography angiography indicates complexity of percutaneous coronary interventions.

BACKGROUND: Coronary computed tomography angiography (CCTA) provides information regarding lesion morphology and three-dimensional coronary anatomy incremental to coronary angiography. We addressed the question whether preprocedural CCTA bears potential for guiding percutaneous coronary interventions (PCI). METHODS AND RESULTS: Sixty-six coronary lesions attempted with PCI within 6 months of preprocedural CCTA were retrospectively assessed. Lesion parameters from unenhanced computed tomography (CT) for calcium scoring and CCTA were analyzed and compared with PCI complexity. Complex PCI was defined as use of buddy wire, kissing balloon, necessity of high pressure balloons, or rotablator. Complex PCIs were observed in 32 interventions (48%). Median Agatston score and Hounsfield units were higher in lesions with complex as compared to those with non-complex interventions with 130 (interquartile range, 23-276) vs 29 (0-158; P=.01), and 493 (245-631) vs 341 (68-520 Hounsfield Units; P=.04), respectively. Median local plaque volume and plaque mass were higher in complex PCI with 17 (2-39) vs 5 (0-19.5 mm³; P=.007), and 48 (15-99) vs. 16 (1.5-63 mg hydroxyapatite/mm³; P=.03), respectively. Lesions leading to complex PCI were longer [1.8 (1.2-2.8) vs 1.3 (0.8-1.7) cm; P=.03], and had a higher rate of calcified plaques (23% vs 3%; P=.03). There was a significant correlation between CCTA- and angiography-derived local SYNTAX Scores (P<.001); the CCTA-derived score seems to be predictive for failed and complex PCI (area under curve = 0.75 ± 0.13 and 0.66 ± 0.08, respectively). CONCLUSIONS: Preprocedural lesion assessment by CCTA indicates complexity of PCI. In patients with suspected complex coronary anatomy, prior CCTA adds important information for planning PCI.

Prothrombotic gene expression profile in vascular smooth muscle cells of human saphenous vein, but not internal mammary artery.

BACKGROUND: The resistance of internal mammary artery (IMA) toward thrombotic occlusion and accelerated atherosclerosis is not well understood. This study analyzed gene expression profiles of vascular smooth muscle cells (VSMCs) from IMA versus saphenous vein (SV). METHODS AND RESULTS: 54'675 probe sets were examined by Affymetrix microarrays. Thirty-one genes belonged to the coagulation system; 2 were differentially expressed, namely tissue factor (TF) and tissue-type plasminogen activator (tPA). TF was 3.1-fold lower in IMA than SV (P=0.006), whereas tPA was 9.0-fold higher (P<0.001). TF mRNA expression was lower in IMA than SV (P<0.05); tPA was higher (P<0.001). TF protein expression was 4.2+/-0.5-fold lower in IMA than SV (P<0.001); tPA was 2.6+/-0.4-fold higher (P<0.01). In IMA VSMC supernatant, TF protein and activity was lower (P<0.05), TFPI and tPA protein higher (P<0.05 and P<0.005), and clotting time of human plasma prolonged (P<0.05) as compared to SV. Migration to TF/FVIIa (10(-9) mol/L) was 3-fold lower in IMA than SV (P=0.01); PAR-2 protein expression was similar (P=NS), PAR-2 blockade without effect (P=NS). CONCLUSIONS: Among the genes of the coagulation system, TF and tPA are differentially expressed in VSMCs from IMA versus SV. This is consistent with protection of IMA from thrombus formation and vascular remodeling.

Pain management: an organizational commitment.

Although much has been done to promote pain assessment and management, pain remains a major, yet largely preventable, public health problem in the United States. A strategy that has been proposed to assure optimal pain management is the development of formal means within institutions to evaluate pain management practices and foster improved outcomes. In response to a pain-related patient care problem, South Nassau Communities Hospital recognized the need to undertake more formal methods for managing patients with acute, chronic, and cancer pain. A Pain Management Task Force was charged with the development of a comprehensive pain management program. Its efforts to date and plans for the future position this institution as ready for the Joint Commission for the Accreditation of Healthcare Organizations' pain assessment and management standards that were introduced in 2000.

Transplant aspiration cytology for monitoring of kidney xenograft (wolf-dog) under cyclosporin A treatment.

Mongrel dogs receiving wolf kidney grafts were treated with Cyclosporin A. The kinetics of the inflammatory response and the display of major histocompatibility (MHC) antigens on graft tubular cells were analyzed by transplant aspiration cytology. Tubular cells aspirated from grafts that underwent repeated rejection episodes showed a higher degree of MHC antigen expression than cells obtained from a well-functioning graft.