Giulia Di Benedetto

Assessment of congenital coronary artery fistulas by transesophageal color Doppler echocardiography

PURPOSE Coronary angiography is the gold standard for imaging the coronary tree, but the relation of coronary artery fistulas to other structures, and their origin and course, may not be apparent. We evaluated the ability of multiplane color Doppler transesophageal echocardiography to identify coronary fistulas. PATIENTS AND METHODS Twenty-one patients with angiographically confirmed coronary artery fistulas were investigated by transesophageal echocardiography in four Italian hospitals between January 1997 and May 2001. RESULTS Transesophageal echocardiography correctly diagnosed fistulous connection in all 21 patients. This included 6 patients with connections from the left circumflex artery (into the right chambers of the heart in 5 patients, and into the left ventricle in 1 patient), 10 patients with a fistula arising from the left anterior descending artery or left main coronary artery (with drainage into the right ventricle or main pulmonary artery), and 5 patients with a fistula from the right coronary artery (with drainage sites in the lateral aspect of the right ventricle, the low posterior right atrium, or the superior vena cava). In 4 of the 21 patients, angiography did not identify the precise site of a fistula into the coronary sinus or right ventricle. CONCLUSION Color Doppler transesophageal echocardiography is useful in the diagnosis and in the precise localization of coronary artery fistulas.

Protective effects of the sigma agonist pre-084 in the rat retina

Aim: With the rationale that amyloid beta (AB) is toxic to the retina, we here assessed the role of TRAIL, a mediator of AB toxicity and related signal transduction, in a rat model. We also attempted to demonstrate possible protective effects of &sgr;1 receptor agonists in these processes. Methods: AB and the &sgr;1 receptor agonist Pre-084 were injected intravitreally in the anaesthetised rat. In additional experiments, the &sgr;1 receptor antagonist BD1047 was administered to assess specificity of the effects of Pre-084. Western blot analysis was performed on retinas to evaluate the expression of TRAIL and TRAIL receptors in the retina, as well as of Bax and phosphorylated JNK following the different treatments. Lactic dehydrogenase (LDH) levels were measured as a cytotoxicity marker. Results: All TRAIL receptors were expressed in rat retinas. Intravitreal injection of AB in rat eyes induced overexpression of TRAIL and the proapoptotic protein Bax, as well as phosphorylation of JNK. All these effects of AB were abrogated by pretreatment with the &sgr;1 receptor agonist Pre-084. Conclusions: It is likely that TRAIL is a mediator of AB effects on the retina. In light of their specific inhibitory effects upon TRAIL expression, it is plausible to hypothesise that &sgr;1 receptor agonists could represent potential pharmacological tools for restraining AB related retinal damage.

Neutralization of Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand Reduces Spinal Cord Injury Damage in Mice

Spinal cord injury (SCI) is a major cause of disability, its clinical outcome depending mostly on the extent of damage in which proapoptotic cytokines have a crucial function. In particular, the inducers of apoptosis belonging to TNF receptor superfamily and their respective ligands are upregulated after SCI. In this study, the function of the proapoptotic cytokine tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) in SCI-induced damage was investigated in the mouse. SCI resulted in severe trauma, characterized by prominent inflammation-related damage and apoptosis. Immunostaining for TRAIL and its receptor DR5 was found in the white and gray matter of the perilesional area, as also confirmed by western blotting experiments. Immunoneutralization of TRAIL resulted in improved functional recovery, reduced apoptotic cell number, modulation of molecules involved in the inflammatory response (FasL, TNF-α, IL-1β, and MPO), and the corresponding signaling (caspase-8 and -3 activation, JNK phosphorylation, Bax, and Bcl-2 expression). As glucocorticoid-induced TNF receptor superfamily-related protein (GITR) activated by its ligand (GITRL) contributes to SCI-related inflammation, interactions between TRAIL and GITRL were investigated. SCI was associated with upregulated GITR and GITRL expression, a phenomenon prevented by anti-TRAIL treatment. Moreover, the expression of both TRAIL and DR5 was reduced in tissues from mice lacking the GITR gene (GITR−/−) in comparison with wild-type mice suggesting that TRAIL- and GITRL-activated pathways synergise in the development of SCI-related inflammatory damage. Characterization of new targets within such molecular systems may constitute a platform for innovative treatment of SCI.

Neutralization of TNFSF10 ameliorates functional outcome in a murine model of Alzheimer’s disease

Alzheimers disease is one of the most common causes of death worldwide, with poor treatment options. A tissue landmark of Alzheimers disease is accumulation of the anomalous protein amyloid-β in specific brain areas. Whether inflammation is an effect of amyloid-β on the Alzheimers disease brain, or rather it represents a cause for formation of amyloid plaques and intracellular tangles remains a subject of debate. TNFSF10, a proapoptotic cytokine of the TNF superfamily, is a mediator of amyloid-β neurotoxicity. Here, we demonstrate that blocking TNFSF10 by administration of a neutralizing monoclonal antibody could attenuate the amyloid-β-induced neurotoxicity in a triple transgenic mouse model of Alzheimers disease (3xTg-AD). The effects of TNFSF10 neutralization on either cognitive parameters, as well as on the expression of TNFSF10, amyloid-β, inflammatory mediators and GFAP were studied in the hippocampus of 3xTg-AD mice. Treatment with the TNFSF10 neutralizing antibody resulted in dramatic improvement of cognitive parameters, as assessed by the Morris water maze test and the novel object recognition test. These results were correlated with decreased protein expression of TNFSF10, amyloid-β, inflammatory mediators and GFAP in the hippocampus. Finally, neutralization of TNFSF10 results in functional improvement and restrained immune/inflammatory response in the brain of 3xTg-AD mice in vivo. Thus, it is plausible to regard the TNFSF10 system as a potential target for efficacious treatment of amyloid-related disorders.

Transesophageal dobutamine stress echocardiography with tissue Doppler imaging for detection and assessment of coronary artery disease.

Abstract Background Transesophageal dobutamine stress echocardiography (T-DSE) has been shown to be a sensitive and specific technique for the detection of myocardial ischemia. A major limitation of echocardiographic study interpretation, however, is the subjective visual analysis of endocardial motion and wall thickening, which is only semiquantitative. Methods To analyze whether T-DSE with the use of tissue Doppler imaging (TDI) during graded dobutamine infusion may be useful to detect and quantify stress-induced myocardial ischemia by changes in myocardial velocities, 70 patients undergoing coronary arteriography were studied with T-DSE and TDI. Midesophageal and transgastric short- and long-axis images were obtained at each level of dobutamine infusion. T-DSE was successful in 67 patients (96%). Baseline resting pulsed and color peak systolic (S) and early diastolic (E) velocities of the anterior, septal, lateral, and inferior walls were examined. Results Pulsed and color TDI correlated well at rest and after stress. Fifteen patients had a normal response to dobutamine, and 52 patients had inducible ischemia by two-dimensional criteria. In the normal group, there was a significant dose-dependent increase in S and E velocities. Compared with those in the normal group, patients with coronary artery disease (CAD) had lower resting S and E velocities and blunted S wave increase or E wave decrease during DSE. Conclusions T-DSE with TDI is a feasible and accurate test for the quantitative assessment of patients with CAD who have impaired augmentation of systolic and diastolic myocardial velocities during dobutamine infusion.

The Proinflammatory Cytokine GITRL Contributes to TRAIL-mediated Neurotoxicity in the HCN-2 Human Neuronal Cell Line

BACKGROUND Cytokines belonging to the TNF superfamily play a relevant role in neurodegenerative processes. Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand (TRAIL), released during neuronal injury, has proven to potently mediate and sustain neurotoxic processes leading to neuronal death. Similarly to TRAIL, the cytokine Glucocorticoid-induced TNF receptor ligand (GITRL) is able to transduce proapoptotic signals. In spite of the array of reports suggesting relationships between TRAIL and other cytokines, scanty data are, so far, available about a GITRL/TRAIL crosstalk. METHODS Here, we investigated possible interactions between TRAIL and the GITRL system in an in vitro model of neurodegeneration, using the human cortical neuronal cell line HCN-2. Cultured HCN-2 neurons were incubated at different times with GITRL and/or TRAIL, and thereafter nucleic acid and protein expression were measured. Real-time PCR analysis showed that the human cortical neuronal cell line HCN-2 does not express GITRL mRNA, but the latter is induced after treatment with TRAIL. In addition, HCN-2 cells did not express the GITRL receptor GITR mRNA, neither in control cultures, nor after treatment with TRAIL. All mRNA data were confirmed by western blot analysis of proteins. Cell viability assay showed that TRAIL, when associated to GITRL, was able to exert additive toxic effects. A counterproof was provided in experiments performed blocking GITRL, in which TRAIL-mediated toxicity appeared significantly reduced. Results suggest that GITRL/TRAIL redundancy during neurodegenerative processes implies extended potentiation of detrimental effects of both cytokines on neurons, eventually leading to larger cell damage and death. CONCLUSION Finally, characterization of novel molecular targets within the TRAIL/GITRL interplay may represent a platform for innovative therapy of neurodegenerative disorders.

Dobutamine stress echocardiography with automated border detection and color kinesis identifies improved diastolic left ventricular function and viable myocardium in ischemic cardiomyopathy

Since the effects of dobutamine on left ventricular systolic and diastolic function are related to the presence of myocardial viability, we attempted to establish if improvement of diastolic wail motion abnormalities assessed with automated border detection (ABD) and color kinesis (CK) has an adjunctive value in detecting hibernating but viable myocardium. 21 patients (pts) with ischemic cardiomyopathy (left ventricular ejection fraction -LVEF-: 0.31-+0.11) were studied with low dose (5-10 mcg/Kg/min) dobutamine stress echocardiography (DSE). ABD waveforms of LV area change and the rate of area change were displayed along with the electrocardiogram and the concurrent cross sectional image. CK digitized LV end-systolic and end-diastolic images were evaluated by reviewing the stored loops obtained in all pts. Endocardial tracking was considered adequate when the visually assessed systolic excursion matched the colorencoded images. Viability was defined as akinetic or hypokinetic segments becoming normokinetic with systolic wall thickening. At baseline and during peak infusion LVEF, peak ejection rate (PER: ml]s), peak filling rate (PFR: ml/s) and mean time of diastolic endocardial motion (tDEM: ms) were calculated. In 10 pts viability was present (group 1), in 11 pts viability was absent (group 2). In group 1 pts there was a significantly increase from baseline to peak infusion in LVEF (0.28-+0.11 vs 0.42_+0.8, p<0.005), PER (1.64-+0.61 vs 2.98--0.97, p<0.005), PFR (1.52--0.53 vs 2.69+0.92, p<0.005) and significant decrease in mean tDEM (304_+41 vs 205--23, p<0.001). In group 2 pts a significantly increase was shown in LVEF (0.27-+0.9 vs 0.38+0.10, p<0.05) and PER (1.41 -+0.72 vs 2.I 1-+0.83, p<0.05); no significant difference was found in PFR (1.39-+0.61 vs 1.74_+0.73, p=NS) and tDEM (315_+39 vs 304_+31, p=NS). Thus, ABD and CK parameters of diastolic function (PFR, tDEM) improved only in pts with hibernating but viable myocardium whereas global systolic function can improve in the presence of both viability and non viability.