Elisabetta Faggin

Expression of Interleukin-10 in Advanced Human Atherosclerotic Plaques: Relation to Inducible Nitric Oxide Synthase Expression and Cell Death

Inflammation is a major feature of human atherosclerosis and is central to development and progression of the disease. A variety of proinflammatory cytokines are expressed in the atherosclerotic plaque and may modulate extracellular matrix remodeling, cell proliferation, and cell death. Little is known, however, about the expression and potential role of anti-inflammatory cytokines in human atherosclerosis. Interleukin-10 (IL-10) is a major anti-inflammatory cytokine whose expression and potential effects in advanced human atherosclerotic plaques have not been evaluated. We studied 21 advanced human atherosclerotic plaques. IL-10 expression was analyzed by use of reverse transcription-polymerase chain reaction and immunohistochemical techniques. Inducible nitric oxide synthase expression was assessed by using immunohistochemistry, and cell death was determined by use of the TUNEL method. Reverse transcription-polymerase chain reaction identified IL-10 mRNA in 12 of 17 atherosclerotic plaques. Immunohistochemical staining of serial sections and double staining identified immunoreactive IL-10 mainly in macrophages, as well as in smooth muscle cells. Consistent with its anti-inflammatory properties, high levels of IL-10 expression were associated with significant decrease in inducible nitric oxide synthase expression (P<0.0001) and cell death (P<0. 0001). Hence, IL-10, a potent anti-inflammatory cytokine, is expressed in a substantial number of advanced human atherosclerotic plaques and might contribute to the modulation of the local inflammatory response and protect from excessive cell death in the plaque.

Myosin Heavy-Chain Isoform Composition and Distribution in Developing and Adult Human Aortic Smooth Muscle

The myosin heavy-chain (MHC) composition of developing and adult human aortic smooth muscle (SM) was studied by SDS-polyacrylamide gel electrophoresis, Western blotting and indirect immunofluorescence using a panel of anti-MHC antibodies. On 5% SDS gels, three bands of 204, 200 and 196 kDa apparent molecular mass were identified in fetal, infant and adult stages of development. In the extracts from thoracic aorta (upper level), the 204, and 200-kDa bands (designated as SM-1 and SM-2, respectively) were recognized by SM-G4 and SMMS-1 antibodies, raised against a SM antigen, whereas the 196-kDa band was reactive with nonmuscle (NM)-F6 and NM-G2 antiplatelet MHC antibodies. Western blotting and immunofluorescence tests performed on bovine brain and other human NM tissues using NM-F6 and NM-G2 indicated that antigenic targets of the two antibodies resembled that of so-called IIB and IIA NM myosin found in the bovine system, respectively. In the aortic media, SM-1 was expressed throughout development, while SM-2 was upregulated during late fetal and postnatal development. Similarly, the 196-kDa band showed two distinct patterns of immunoreactivity with the anti-NM-MHC antibodies: with NM-G2, antigenicity was equal at all the developmental stages examined, whereas with NM-F6, it diminished during postnatal development. In the upper level, the cellular distribution of NM-G2 and NM-F6 immunoreactivities was similar in the early fetus but quite distinct at later stages of development. In infant and adult subjects, SM cells (SMC) reactive with NM-F6 accumulated predominantly within the intimal layer as well as in some areas of the underlying media as cell foci, whereas NM-G2 homogeneously stained the two layers. In the aorta near the diaphragm (lower level), both antibodies stained the thickened intima but not the underlying media. These data are consistent with the existence of developmental, stage-specific molecular and cellular transitions during vascular SMC maturation in human aortic media. In addition, these data suggest that IIB-like myosin may be expressed in SMC involved specifically in intimal thickening.

Myosin Isoform Expression in Smooth Muscle Cells during Physiological and Pathological Vascular Remodeling

There is substantial evidence indicating that the study of cytoskeletal and cytocontractile protein composition in vascular smooth muscle cells (SMCs) can be valuable in tracing structural changes during vascular remodeling. Recent nucleic acid and protein investigations suggest that myosin can be used as a new specific marker for the identification of SMC phenotypes in some pathological conditions affecting the vascular wall. In view of this new information, it would seem timely to review the structural bases of myosin isoform expression in the vascular smooth muscle system as well as the factors involved in its regulation. A puzzling feature has arisen in recent studies on this topic: the presence of non-muscle myosin variants in SMCs during physiological and pathological vascular remodeling. In the response to injury caused by mechanical, chemical and hormonal factors in animals, characterized by proliferation and migration of vascular SMCs from the media to the intima, there is a partial or complete recapitulation of a myosin isoform pattern pertinent to developing vascular smooth muscle tissue. Analysis of myosin isoform content in the vascular wall also demonstrates that: (1) changes in SMC composition may occur independent of medial SMC migration into intima, and (2) the presence of fetal-type SMCs in the neointima is not necessarily related to specific positional changes of medial SMCs.

Atorvastatin Reduces Macrophage Accumulation in Atherosclerotic Plaques A Comparison of a Nonstatin-Based Regimen in Patients Undergoing Carotid Endarterectomy

Background and Purpose— The object of our study was to compare the effect of high-dose vs low-dose atorvastatin vs nonstatin-based treatment (cholestyramine plus sitosterol) on cell composition of carotid plaque. Methods— We recruited 60 hypercholesterolemic patients (total cholesterol, 5.83-7.64 mmol/L) eligible for carotid endarterectomy. Three months before surgery, patients were randomized into 3 groups (n=20) receiving atorvastatin 10 mg/day (AT-10) or atorvastatin 80 mg/day (AT-80) or cholestyramine 8 g/day plus sitosterol 2.5 g/day. Analysis of cell composition was performed on endarterectomy specimens. Results— The 3 treatments resulted in a significant reduction of total cholesterol and low-density lipoprotein cholesterol (LDL-C), although the decrease in total cholesterol and LDL-C was of smaller magnitude in the cholestyramine plus sitosterol group. The 3 regimens did not influence the levels of inflammatory markers (including high-sensitivity C-reactive protein). Macrophage content was significantly lower in the AT-10 group plaques compared to the cholestyramine plus sitosterol group. It was further reduced in the AT-80 group plaques. These differences were no longer significant after adjustment for changes in LDL-C. No difference in lymphocyte number was observed among treatments, whereas the content of smooth muscle cells was higher in the AT- 80 group. An inverse association was observed between LDL-C changes in the 3 groups and macrophage content in the plaques. Conclusions— Short-term treatment with high-dose statin is superior to a nonstatin lipid-lowering regimen in reducing the macrophage cell content within atherosclerotic lesions, but this effect was determined by the degree of LDL-C-lowering.

Specific Cellular Features of Atheroma Associated With Development of Neointima After Carotid Endarterectomy The Carotid Atherosclerosis and Restenosis Study

BACKGROUND The purpose of this study was to investigate whether some cellular and molecular features of tissue retrieved at carotid endarterectomy are associated with the extent of neointima formation at ultrasound follow-up. METHODS AND RESULTS One hundred fifty patients were studied. Endarterectomy specimens were tested by immunocytochemistry with the use of (1) monoclonal antibodies that identify smooth muscle cells (SMCs) and fetal-type SMCs on the basis of smooth muscle and nonmuscle myosin content, (2) the anti-macrophage HAM 56, and (3) the anti-lymphocyte CD45RO. The maximum intima-media thickness (M-IMT) of the revascularized vessel was assessed by the use of B-mode ultrasonography 6 months after surgery. The M-IMT values were related positively to the number of SMCs (r=0.534, P<0.0005) and negatively to that of macrophages and lymphocytes (r=-0.428, P<0.0005, and -0.538, P=0.001, respectively). Patients were classified as class 1 (M-IMT </=1.0 mm), class 2 (1. 01.3 mm). An abundance of SMCs, mostly of fetal type, was found in the plaque of class 3 patients, whereas lesions from class 1 patients were rich in macrophages and lymphocytes. In the multivariate analysis, factors related to M-IMT were the number of SMCs and the percentage of fetal-type SMCs present in the plaque. CONCLUSIONS Although the classic risk factors did not play a role, an abundance of SMCs and a scarcity of macrophages characterized the primary lesion of patients in whom neointima developed after surgery. In patients in whom neointima did not develop, lesions were rich in macrophages and lymphocytes. This approach can be useful in defining patients at risk of restenosis.

Hypertension and vascular calcification: a vicious cycle?

It is now well established that hypertension is accompanied by remodeling of the arterial wall with significant modifications in extracellular matrix composition and in vascular cell phenotype. Some of these changes, particularly elastin fragments generation, increased proteases activity and activation of transforming growth factor-&bgr; signaling together with deposition of collagen and proteoglycans might generate a permissive soil for vascular calcification. On the other hand, calcium deposits within large arterial conduits can reduce vessels elasticity and contribute to the generation of blood pressure pattern associated with vascular stiffness, namely isolated systolic hypertension. Hence, a hypothetical vicious cycle exists between hypertensive arterial damage and vascular calcification. Herein, we revised clinical and basic science findings supporting this possibility.

Clones of Interstitial Cells From Bovine Aortic Valve Exhibit Different Calcifying Potential When Exposed to Endotoxin and Phosphate

Objective—Our purpose was to study in vitro whether phenotypically-distinct interstitial cell clones from bovine aortic valve (BVIC) possess different calcifying potential in response to endotoxin (lipopolysaccharide [LPS]) and phosphate (Pi). Methods and Results—Among various clones of BVIC obtained by limited dilution technique we selected 4 clones displaying different growth patterns and immunophenotypes. Uncloned and cloned cells were treated with combinations of LPS (100 ng/mL) and Pi (2.4 mmol/L). Uncloned BVIC showed increased alkaline phosphatase activity (ALP) after treatment with LPS, which resulted in calcification after addition of Pi. Among BVIC clones, only Clone 1 (fibroblast-like phenotype) showed a relevant increase in ALP after LPS treatment in parallel with prevention of smooth muscle (SM) α-actin accumulation. No effect was observed in clonal cells harboring a more stable SM cell-like profile (Clone 4). None of the isolated clones calcified but mineralization was induced in the presence of LPS plus Pi when Clone 1 was cocultured with Clone 4 or after seeding on type I collagen sponges. Conclusion—Endotoxin and phosphate can act as valve calcification promoters by targeting specific fibroblast-like interstitial valve cells that possess a unique procalcific potential.

Association between the −514 c→t polymorphism of the hepatic lipase gene promoter and unstable carotid plaque in patients with severe carotid artery stenosis ☆

OBJECTIVE We investigated the potential association between -514 C-->T polymorphism in the promoter of the hepatic lipase gene (LIPC) and the prevalence of inflammatory cells in the plaque of patients with severe carotid artery stenosis. BACKGROUND This common LIPC polymorphism has been related to the presence of an atherogenic lipoprotein pattern. METHODS We studied 68 consecutive patients undergoing carotid endarterectomy. The LIPC genotype was determined by polymerase chain reaction. Endarterectomy specimens were examined by immunocytochemistry using monoclonal antibodies for smooth muscle cells, macrophages, or lymphocytes. RESULTS In 50 of 68 patients who had evidence of previous ipsilateral ischemic events, 36 (72%) were carriers of the CC genotype, whereas only 14 (28%) were carriers of the CT/TT genotype (p = 0.002). Among the 18 patients without evidence of events, the two genotypes were equally distributed (9 vs. 9). The low-density lipoprotein (LDL) particles were denser in CC than in CT/TT genotype carriers (flotation rate: 0.315 +/- 0.025 vs. 0.356 +/- 0.019, p < 0.0005). The CC genotype was associated with an abundance of macrophages (6.7 +/- 3.5 vs. 2.1 +/- 2.1 cells/area unit in the CT/TT group, p < 0.0005) and a reduced number of smooth muscle cells (6.9 +/- 6.2 vs. 14.5 +/- 6.4 in the CT/TT group, p < 0.0005) in the plaque. An inverse relationship was found between LDL buoyancy and the number of macrophages in the plaque (r = -0.639, p < 0.0005). CONCLUSION We provide evidence, for the first time, that LIPC promoter -514 C-->T polymorphism, by modulating LDL density, significantly affects the number of macrophages in the plaque and possibly affects the occurrence of cerebrovascular events in patients with carotid artery stenosis.

Atherosclerosis progression in psoriatic arthritis patients despite the treatment with tumor necrosis factor-alpha blockers: A two-year prospective observational study

OBJECTIVE To evaluate the progression of subclinical atherosclerosis in Psoriatic Arthritis (PsA) patients treated with anti-tumor necrosis factor (TNF)-α agents. METHODS Thirty-two PsA patients classified according to the CASPAR criteria and attending the Rheumatology Unit of the University of Padua Medical Center were enrolled in a two-year prospective, observational study. In accordance with the ASAS/EULAR recommendations on the management of these patients, those studied were prescribed biological agents [etanercept (n=21), adalimumab (n=6), infliximab (n=5)]. Plasma lipids, inflammatory biomarkers, including C-reactive protein (CRP), interleukin-6 (IL-6), vessel endothelium growth factor (VEGF), osteoprotegerin (OPG), and TNF-α, as well as Disease Activity Score 28 calculated with CRP (DAS 28-CRP) were evaluated at baseline and after two years of treatment. Bilateral carotid B-mode ultrasound measurements [the mean-intima media thickness (mean-IMT), the mean maximum-IMT (M-Max)] of each carotid artery segment (common, bulb, and internal carotid artery) and the post-occlusion flow-mediated dilation (FMD) of the brachial artery were also assessed at baseline and after two years. RESULTS Despite an improvement in the DAS 28-CRP score (P<0.0005) and lower low-density lipoprotein cholesterol (P<0.013) and triglyceride (P<0.036) values, there was a significant progression in both the mean-IMT (P<0.0005) and M-Max (P<0.0005). Moreover, no recovery in FMD (P=ns) was observed after two years of anti TNF-α treatment. Serum TNF-α levels were increased (P=0.003) and OPG values were decreased (P=0.011) at the end of follow- up with respect to baseline values. CONCLUSIONS Despite improvement in clinical status, arterial remodelling was observed in the PsA patients who were treated with anti TNF-α agents for two years.

Amiodarone impairs trafficking through late endosomes inducing a Niemann-Pick C-like phenotype

Abstract Patients treated with amiodarone accumulate lysobisphosphatidic acid (LBPA), also known as bis(monoacylglycero)phosphate, in airway secretions and develop in different tissues vacuoles and inclusion bodies thought to originate from endosomes. To clarify the origin of these changes, we studied in vitro the effects of amiodarone on endosomal activities like transferrin recycling, Shiga toxin processing, ESCRT-dependent lentivirus budding, fluid phase endocytosis, proteolysis and exosome secretion. Furthermore, since the accumulation of LBPA might point to a broader disturbance in lipid homeostasis, we studied the effect of amiodarone on the distribution of LBPA, unesterified cholesterol, sphingomyelin and glycosphyngolipids. Amiodarone analogues were also studied, including the recently developed derivative dronedarone. We found that amiodarone does not affect early endosomal activities, like transferrin recycling, Shiga toxin processing and lentivirus budding. Amiodarone, instead, interferes with late compartments of the endocytic pathway, blocking the progression of fluid phase endocytosis and causing fusion of organelles, collapse of lumenal structures, accumulation of undegraded substrates and amassing of different types of lipids. Not all late endocytic compartments are affected, since exosome secretion is spared. These changes recall the Niemann-Pick type-C phenotype (NPC), but originate by a different mechanism, since, differently from NPC, they are not alleviated by cholesterol removal. Studies with analogues indicate that basic pKa and high water-solubility at acidic pH are crucial requirements for the interference with late endosomes/lysosomes and that, in this respect, dronedarone is at least as potent as amiodarone. These findings may have relevance in fields unrelated to rhythm control.