Maurizio Taurino

Detection of aortic graft infection with leukocytes labeled with technetium 99m—hexametazime

PURPOSE To reduce the rates of morbidity and mortality in aortic graft infection, a new diagnostic approach is needed to help identify low-grade stages, specifically when there are minimal or no clinical signs of overt infection. The aim of this study was to evaluate the role of technetium 99m--hexametazime white blood cell scanning (99mTc scanning) in detecting aortic graft infection, particularly in the low-grade stages. METHODS AND RESULTS Thirty-seven patients with suspected aortic graft infection were categorized into three groups according to their signs and symptoms on readmission. Ten patients (group A) had advanced graft infections that were correctly diagnosed by use of computed tomography (CT) scanning and 99mTc scanning and confirmed by intraoperative findings and culture results. Eighteen patients (group B) had nonspecific signs and symptoms of graft infection. Patients only underwent CT and 99mTc scanning for graft infection after standard clinical work-ups failed to reveal disease processes that accounted for the clinical symptoms. In this group of patients 99mTc scanning identified four cases of low-grade graft infection, which was confirmed by intraoperative findings and graft cultures. None of these four cases was confirmed by results of CT scanning. On an average 18-month follow-up in patients who did not undergo surgery graft infections developed. Nine patients (group C) had anastomotic aneurysms; CT scanning and 99mTc scanning correctly diagnosed five patients as being infected. The result of 99mTc scanning was false-positive in one patient. CONCLUSIONS The diagnostic accuracy of 99mTc scanning in patients who did not have specific signs of graft infection (groups B and C) was 100% for sensitivity, 94.4% for specificity, 90% for the positive predictive value, and 100% for the negative predictive value. 99mTc scanning seems to be a useful diagnostic technique for detecting aortic graft infection, particularly in low-grade stages.

Accelerated Lipid-Induced Atherogenesis in Galectin-3-Deficient Mice Role of Lipoxidation via Receptor-Mediated Mechanisms

Objective—Modified lipoproteins, particularly oxidized LDLs, are believed to evoke an inflammatory response which participates in all stages of atherosclerosis. Disposal of these particles is mediated through receptors which may trigger proinflammatory signaling pathways leading to vascular injury. This study was aimed at assessing the role in atherogenesis of one of these receptors, galectin-3. Methods and Results—Galectin-3–deficient and wild-type mice were fed an atherogenic diet or standard chow for 8 months. Lesion area and length were higher in galectin-3–deficient versus wild-type mice. At the level of the aortic sinus, wild-type animals showed only fatty streaks, whereas galectin-3–deficient mice developed complex lesions, associated with extensive inflammatory changes. This was indicated by the presence of T lymphocytes with activated Th1-phenotype and by more marked monocyte-macrophage infiltration, inflammatory mediator expression, vascular cell apoptosis, and proinflammatory transcription factor activation. Increased accumulation of oxidixed LDLs and lipoxidation products and upregulation of other receptors for these compounds, including the proinflammatory RAGE, were detected in galectin-3–deficient versus wild-type mice. Conclusions—These data suggest a unique protective role for galectin-3 in the uptake and effective removal of modified lipoproteins, with concurrent downregulation of proinflammatory pathways responsible for atherosclerosis initiation and progression.

The galectin-3/RAGE dyad modulates vascular osteogenesis in atherosclerosis

AIMS Vascular calcification correlates with inflammation and plaque instability in a dual manner, depending on the spotty/granular (micro) or sheet-like/lamellated (macro) pattern of calcification. Modified lipoproteins trigger both inflammation and calcification via receptors for advanced lipoxidation/glycation endproducts (ALEs/AGEs). This study compared the roles of galectin-3 and receptor for AGEs (RAGE), two ALEs/AGEs-receptors with diverging effects on inflammation and bone metabolism, in the process of vascular calcification. METHODS AND RESULTS We evaluated galectin-3 and RAGE expression/localization in 62 human carotid plaques and its relation to calcification pattern, plaque phenotype, and markers of inflammation and vascular osteogenesis; and the effect of galectin-3 ablation and/or exposure to an ALE/AGE on vascular smooth muscle cell (VSMC) osteogenic differentiation. While RAGE co-localized with inflammatory cells in unstable regions with microcalcification, galectin-3 was expressed also by VSMCs, especially in macrocalcified areas, where it co-localized with alkaline phosphatase. Expression of galectin-3 and osteogenic markers was higher in macrocalcified plaques, whereas the opposite occurred for RAGE and inflammatory markers. Galectin-3-deficient VSMCs exhibited defective osteogenic differentiation, as shown by altered expression of osteogenic transcription factors and proteins, blunted activation of pro-osteoblastogenic Wnt/β-catenin signalling and proliferation, enhanced apoptosis, and disorganized mineralization. These abnormalities were associated with RAGE up-regulation, but were only in part prevented by RAGE silencing, and were partially mimicked or exacerbated by treatment with an AGE/ALE. CONCLUSION These data indicate a novel molecular mechanism by which galectin-3 and RAGE modulate in divergent ways, not only inflammation, but also vascular osteogenesis, by modulating Wnt/β-catenin signalling, and independently of ALEs/AGEs.

Relationships between risk factors and morphological patterns of human carotid atherosclerotic plaques. A multivariate discriminant analysis

The histological characterization of the fibroatheromatous plaques and their histogenesis are still to be defined. Factors responsible for the evolution of intimal components and the mechanisms and stages of fibroatheromatous plaque formation are still largely obscure. Focusing on symptomatic plaques, the aim of this study is to determine whether plaque heterogeneity is the result of a haphazard clustering of various components or an organized pattern in response to risk factors. To this end, 180 carotid plaques from patients affected by transient ischemic attacks (TIA) or by stroke, with angiographic stenosis greater than 50%, were studied after endoarterectomy. Clinical and morphological data were collected by means of a pre-defined protocol, quantified and correlated, by using the discriminant analysis, with age, sex, hypertension, diabetes, hypercholesterolemia and smoking habit. Our results show that the relationships between plaque components are non-random and consistent with the knowledge derived from studies on human and experimental plaques. Moreover, some plaque patterns can be significantly correlated with single risk factors. The fibrous plaque was correlated with aging and diabetes; the granulomatous plaque, rich in giant cells, with the female sex and hypertension; the xanthomatous plaque, rich in foam cells and with extensive alcianophilia, with hypercholesterolemia. In the smokers, finally, the plaques were frequently complicated by mural thrombosis.

Cerebral Embolization during Transcervical Carotid Stenting with Flow Reversal: A Diffusion-Weighted Magnetic Resonance Study

Transfemoral filter-protected carotid artery stenting (CAS) has emerged as a valid alternative to carotid surgery. To overcome the drawbacks of femoral access for CAS and reduce embolic load, some have proposed cervical access with internal carotid artery (ICA) flow reversal. In a series of patients at high risk for femoral access who underwent transcervical CAS with ICA flow reversal, we report clinical outcome and intraoperative embolization rates measured by diffusion-weighted magnetic resonance imaging (DW-MRI). A series of 48 patients were selected for transcervical CAS with carotid flow reversal from September 2004 to July 2007. The indications used for this technique were age >or=80 years, severe aortic and epiaortic vessel tortuosity, widespread calcification of aortic arch or epiaortic vessels, severe aortoiliac occlusive disease, large abdominal aortic aneurysm, and aortobifemoral prosthesis. During the procedure, no adjunctive maneuvers such as external carotid artery balloon occlusion were used. Of the 48 patients, 43 underwent preoperative and postoperative cerebral DW-MRI. The death/stroke rate in the 48 patients was 2.1% (one transient ischemic attack, one minor stroke, and no deaths). None of the procedures led to carotid dissections or access-site complications. Of the 43 patients who underwent DW-MRI, 16 new ischemic lesions were disclosed in six patients (13.9%), four (9.3%) of whom remained asymptomatic. All ischemic lesions were ipsilateral to the treated carotid artery. In patients at high risk for the transfemoral approach, transcervical carotid stenting with flow reversal achieves good technical and clinical results and seems able to reduce the incidence of postoperative DW-MRI ischemic lesions previously reported for transfemoral filter-protected CAS.

Doppler ultrasonography and exercise testing in diagnosing a popliteal artery adventitial cyst.

We describe popliteal arterial adventitial cystic disease which causes intermittent claudication in a young athletic man, with atypical manifestation, without loss of foot pulses on knee flexion nor murmur in the popliteal fossa. The findings obtained from Magnetic Resonance Imaging were non-diagnostic. The diagnosis resulted from Echo-Doppler ultrasonography along with peak exercise testing. Ultrasonography also provided useful physiopathological informations suggesting that a popliteal artery adventitial cyst can become symptomatic if muscle exertion increases fluid pressure within the cyst, enough to cause hemodynamically significant endoluminal stenosis. Rapid diagnosis is essential to prevent progressive claudication threatening limb viability. To guarantee this professional sportsman a reliable and durable outcome, instead of less aggressive management, we resected the involved arterial segment and interposed an autologous saphenous-vein graft.

Cervical Access for Filter-protected Carotid Artery Stenting: A Useful Tool to Reduce Cerebral Embolisation

BACKGROUND Filter-protected transcervical carotid artery stenting (CAS) has been suggested to reduce the intraoperative cerebral embolisation observed during transfemoral CAS. We therefore evaluated clinical outcome and incidence of ischaemic lesions at diffusion-weighted magnetic resonance imaging (DW-MRI) after transcervical and transfemoral CAS. METHODS From March 2007 to May 2009, we performed filter-protected CAS in 135 patients with symptomatic (30%) or asymptomatic (70%) carotid stenosis above 70% and below 95%. In 44 patients with risky femoral access or unfavourable aortic arch anatomy, access to common carotid artery was achieved by a small cervical incision. In another 91 procedures we used a classic percutaneous femoral access. Preoperative and postoperative DW-MRI scans were obtained after 111 procedures (82%) - 35 transcervical and 76 transfemoral. RESULTS The incidence of clinical events (transient ischaemic attack (TIA) and stroke) was 2.3% after transcervical CAS and 19.8% after transfemoral CAS (P<0.01), without any deaths. DW-MRI disclosed new ischaemic lesions in five patients (5/35, 14.3%) after transcervical CAS and in 28 patients (28/76, 36.8%) after transfemoral CAS (P=0.015). All ischaemic lesions depicted after transcervical procedures were ipsilateral to the treated artery. CONCLUSIONS Transcervical filter-protected CAS, compared with classic percutaneous procedures, seems to reduce clinical events and DW-MRI ischaemic damage and may be useful in selected patients.

The multitasking role of macrophages in Stanford type A acute aortic dissection.

Objectives: The aim of the study was to determine whether the release by macrophages of matrix metalloproteinase (MMP)-12 and vascular endothelial growth factor (VEGF) - leading to inflammation, matrix degradation and neoangiogenesis - represents an effective pathway that underlies aortic wall remodeling in Stanford type A acute aortic dissection (AAD). Methods: Twenty-one consecutive patients with no genetic predisposition, with Stanford type A AAD were selected. In each patient, the levels of serum VEGF, MMP-12, serum interleukin (IL)-6, IL-8 and monocyte chemoattractant protein (MCP)-1 were evaluated using enzyme-linked immunosorbent assay. Ascending aortic specimens were collected for immunohistochemical identification of any presence of inflammatory infiltrate, VEGF and CD31 expression. Results: A significant increase in serum VEGF (p = 0.044), MMP-12 (p = 0.007), IL-6 (p = 0.0001), IL-8 (p = 0.0001) and MCP-1 (p = 0.0001) levels was observed in the AAD group compared to the control group. Furthermore, all AAD samples were positive for VEGF in the tunica media and showed vessel growth and immune-inflammatory infiltrate. A large number of cases (62.79%) showed inflammation at the edge of the dissection and approximately half (51.42%) showed neovessels growing at the edge of the dissection. Conclusions: The results suggest that VEGF-mediated angiogenesis and matrix degradation play a role in AAD. Finally, we believe that MMP-12 should be considered a marker of AAD.

Metalloproteinase Expression in Carotid Plaque and Its Correlation With Plasma Levels Before and After Carotid Endarterectomy

Purpose To assess baseline and follow-up plasma concentrations of metalloproteinase-9 (MMP-9), MMP-2, and tissue inhibitor of metalloproteinase-2 (TIMP-2) in patients undergoing carotid thromboendarterectomy (TEA) in relation to tissue expression and diagnostic features. Basic Methods Using sandwich enzyme-linked immunosorbent assay, plasma levels of enzymes were determined in 15 patients undergoing carotid TEA. Tissue sections were incubated with specific antibodies and fluorescence intensity was analyzed. Principal Findings MMP-9 levels were higher in patients with carotid stenosis versus controls, significantly in those with cerebral lesions at neuroimaging. MMP-9 levels decreased in 93.4% of the patients at 1 month. MMP-2 levels tended to increase 30 days after surgery. TIMP-2 showed no difference. Conclusions High concentrations of MMP-9 found in patients with carotid stenosis and cerebral lesions suggest that MMP-9 assay could be useful in the evaluation of all carotid lesions to help identify those at highest risk of a neurologic event.

Detecting microcalcifications in atherosclerotic plaques by a simple trichromic staining method for epoxy embedded carotid endarterectomies

Atherosclerotic plaques have a high probability of undergoing rapid progression to stenosis, becoming responsible of acute coronary syndrome or stroke. Microcalcifications may act as enhancers of atherosclerotic plaque vulnerability. Considering that calcifications with a diameter smalller than 10 µm in paraffin embedded tissue are rather difficult to detect, our aim was to analyze microcalcifications on semithin sections from epoxy resin embedded samples of carotid endarterectomies using an original trichromic stain (methylene blue-azur B - basic fuchsine - alizarin red). We have compared samples stained either with our method, methylene blue-azur B alone or with Von Kossa staining, and methylene blue-azur B -basic fuchsine alone or with Von Kossa staining. Our method resulted to be simple and fast (ca. 2 min), it gives a sharp general contrast for all structures and allows to easy identify collagen and elastin. In addition, gray-green colour associated to intracellular lipid droplets evidences foam cells, which are particularly abundant in endarterectomies samples. Mast cells and their metachromatic granules are also well recognized. Calcifications over 0,5 µm are clearly recognizable. In conclusion, microcalcifications are clearly distinguished from the extracellular matrix in spite of their reduced dimensions. Methylene blue-azur B-basic fuchsine-alizarin red method is easy to use, reproducible, and is particularly suitable for the identification of microcalcifications in the morphological analysis of atherosclerotic plaques.