Selective in vivo visualization of immune-cell infiltration in a mouse model of autoimmune myocarditis by fluorine-19 cardiac magnetic resonance.

BACKGROUND: The goal of this study was to characterize the performance of fluorine-19 ((19)F) cardiac magnetic resonance (CMR) for the specific detection of inflammatory cells in a mouse model of myocarditis. Intravenously administered perfluorocarbons are taken up by infiltrating inflammatory cells and can be detected by (19)F-CMR. (19)F-labeled cells should, therefore, generate an exclusive signal at the inflamed regions within the myocardium. METHODS AND RESULTS: Experimental autoimmune myocarditis was induced in BALB/c mice. After intravenous injection of 2×200 µL of a perfluorocarbon on day 19 and 20 (n=9) after immunization, in vivo (19)F-CMR was performed at the peak of myocardial inflammation (day 21). In 5 additional animals, perfluorocarbon combined with FITC (fluorescein isothiocyanate) was administered for postmortem immunofluorescence and flow-cytometry analyses. Control experiments were performed in 9 animals. In vivo (19)F-CMR detected myocardial inflammation in all experimental autoimmune myocarditis-positive animals. Its resolution was sufficient to identify even small inflammatory foci, that is, at the surface of the right ventricle. Postmortem immunohistochemistry and flow cytometry confirmed the presence of perfluorocarbon in macrophages, dendritic cells, and granulocytes, but not in lymphocytes. The myocardial volume of elevated (19)F signal (rs=0.96; P<0.001), the (19)F signal-to-noise ratio (rs=0.92; P<0.001), and the (19)F signal integral (rs=0.96; P<0.001) at day 21 correlated with the histological myocarditis severity score. CONCLUSIONS: In vivo (19)F-CMR was successfully used to visualize the inflammation specifically and robustly in experimental autoimmune myocarditis, and thus allowed for an unprecedented insight into the involvement of inflammatory cells in the disease process.

Bowel ischemia: a rare complication of thiopental treatment for status epilepticus.

BACKGROUND: Refractory status epilepticus (RSE) treatment is usually performed with coma induction using an appropriate general anesthetic. Most frequent complications are represented by hypotension and infection. Other side-effects may however be encountered. OBSERVATIONS: We describe two patients suffering from acute bowel ischemia after thiopental (THP) treatment for RSE. A 73-year-old man with a complex-patial RSE following an acute stroke received THP (303 mg/kg over 48 h); 36 h after THP discontinuation, he presented abdominal tenderness and lactate elevation. Necrosis of the terminal ileum and colon was seen during surgical exploration; he deceased shortly thereafter. A 21 year-old woman had a cryptogenic de novo generalized-convulsive RSE resistant to 5 attempts of EEG burst-suppression. During the 6th attempt, after THP (840 mg/kg over 150 h) together with mild hypothermia, she developed an ileus with elevated serum lactate; caecum necrosis was observed during surgery. Hypernatremia, acidosis and hyperlactatemia heralded this complication in both patients. CONCLUSION: In these two patients, mechanical vascular ischemia may have resulted from drug-induced paralytic ileus. To our knowledge, this is the first report describing this potential fatal side effect in adults with RSE.

Gene transfer of programmed death ligand-1.Ig prolongs cardiac allograft survival.

BACKGROUND: The CD28 homologue programmed death-1 (PD-1) and its ligands, PD-L1 and PD-L2 (which are homologous to B7), constitute an inhibitory pathway of T cell costimulation. The PD-1 pathway is of interest for immune-mediated diseases given that PD-1-deficient mice develop autoimmune diseases. We have evaluated the effect of local overexpression of a PD-L1.Ig fusion protein on cardiac allograft survival. METHODS: Adenovirus-mediated PD-L1.Ig gene transfer was performed in F344 rat donor hearts placed in the abdominal position in Lewis recipients. Inflammatory cell infiltrates in the grafts were assessed by immunohistochemistry. RESULTS: Allografts transduced with the PD-L1.Ig gene survived for longer periods of time compared with those receiving noncoding adenovirus or virus dilution buffer alone: median survival time (MST), 17 (range: 16-20) days vs. 11 (8-14) and 9 (8-13) days, respectively (P < 0.001). PD-L1.Ig gene transfer combined with a subtherapeutic regimen of cyclosporin A (CsA) was superior to CsA alone: MST, 25 (15-42) vs. 15 (13-19) days (P < 0.05). PD-L1.Ig gene transfer was associated with decreased numbers of CD4 cells and monocytes/macrophages infiltrating the graft (P < 0.05). CONCLUSIONS: Localized PD-L1.Ig expression in donor hearts attenuates acute allograft rejection in a rat model. The effect is additive to that of a subtherapeutic regimen of CsA. These results suggest that targeting of PD-1 by gene therapy may inhibit acute cardiac allograft rejection in vivo.

Critical single proximal left arterial descending coronary artery stenosis to mimic chronic myocardial ischemia: a new model induced by minimal invasive technology.

BACKGROUND/AIMS: The present report examines a new pig model for progressive induction of high-grade stenosis, for the study of chronic myocardial ischemia and the dynamics of collateral vessel growth. METHODS: Thirty-nine Landrace pigs were instrumented with a novel experimental stent (GVD stent) in the left anterior descending coronary artery. Eight animals underwent transthoracic echocardiography at rest and under low-dose dobutamine. Seven animals were examined by nuclear PET and SPECT analysis. Epi-, mid- and endocardial fibrosis and the numbers of arterial vessels were examined by histology. RESULTS: Functional analysis showed a significant decrease in global left ventricular ejection fraction (24.5 +/- 1.6%) 3 weeks after implantation. There was a trend to increased left ventricular ejection fraction after low-dose dobutamine stress (36.0 +/- 6.6%) and a significant improvement of the impaired regional anterior wall motion. PET and SPECT imaging documented chronic hibernation. Myocardial fibrosis increased significantly in the ischemic area with a gradient from epi- to endocardial. The number of arterial vessels in the ischemic area increased and coronary angiography showed abundant collateral vessels of Rentrop class 1. CONCLUSION: The presented experimental model mimics the clinical situation of chronic myocardial ischemia secondary to 1-vessel coronary disease.

Diagnostic contribution of cardiac magnetic resonance in patients with acute coronary syndrome and culprit-free angiograms.

BACKGROUND: In spite of robust knowledge about underlying ischemic myocardial damage, acute coronary syndromes (ACS) with culprit-free angiograms raise diagnostic concerns. The present study aimed to evaluate the additional value of cardiac magnetic resonance (CMR) over commonly available non-CMR standard tests, for the differentiation of myocardial injury in patients with ACS and non-obstructed coronary arteries. MATERIAL/METHODS: Patients with ACS, elevated hs-TnT, and a culprit-free angiogram were prospectively enrolled into the study between January 2009 and July 2013. After initial evaluation with standard tests (ECG, echocardiography, hs-TnT) and provisional exclusion of acute myocardial infarction (AMI) in coronary angiogram, patients were referred for CMR with the suspicion of myocarditis or Takotsubo cardiomyopathy (TTC). According to the result of CMR, patients were reclassified as having myocarditis, AMI, TTC, or non-injured myocardium as assessed by late gadolinium enhancement. RESULTS: Out of 5110 patients admitted with ACS, 75 had normal coronary angiograms and entered the study; 69 of them (92%) were suspected for myocarditis and 6 (8%) for TTC. After CMR, 49 patients were finally diagnosed with myocarditis (65%), 3 with TTC (4%), 7 with AMI (9%), and 16 (21%) with non-injured myocardium. The provisional diagnosis was changed or excluded in 23 patients (31%), with a 9% rate of unrecognized AMI. CONCLUSIONS: The study results suggest that the evaluation of patients with ACS and culprit-free angiogram should be complemented by a CMR examination, if available, because the initial work-up with non-CMR tests leads to a significant proportion of misdiagnosed AMI.

Cardiac rotation and relaxation in patients with aortic valve stenosis.

BACKGROUND: Diastolic dysfunction with delayed relaxation and abnormal passive elastic properties has been described in patients with severe pressure overload hypertrophy. The purpose of this study was to evaluate the time course of rotational motion of the left ventricle in patients with aortic valve stenosis using myocardial tagging. METHODS: Myocardial tagging is a non-invasive method based on magnetic resonance which makes it possible to label ('tag') specific myocardial regions. From the motion of the tag's cardiac rotation, radial displacement and translational motion can be determined. In 12 controls and 13 patients with severe aortic valve stenosis systolic and diastolic wall motion was assessed in an apical and basal short axis plane. RESULTS: The normal left ventricle performs a systolic wringing motion around the ventricular long axis with clockwise rotation at the base (-4.4+/-1.6 degrees) and counter-clockwise rotation at the apex (+6.8+/-2.5 degrees) when viewed from the apex. During early diastole an untwisting motion can be observed which precedes diastolic filling. In patients with aortic valve stenosis systolic rotation is reduced at the base (-2.4+/-2.0 degrees; P<0.01) but increased at the apex (+12.0+/-6.0 degrees; P<0.05). Diastolic untwisting is delayed and prolonged with a decrease in normalized rotation velocity (-6.9+/-1.1 s(-1)) when compared to controls (-10.7+/-2.2 s(-1); P<0.001). Maximal systolic torsion is 8.0+/-2.1 degrees in controls and 14.1+/-6.4 degrees (P<0.01) in patients with aortic valve stenosis. CONCLUSIONS: Left ventricular pressure overload hypertrophy is associated with a reduction in basal and an increase in apical rotation resulting in increased torsion of the ventricle. Diastolic untwisting is delayed and prolonged. This may explain the occurrence of diastolic dysfunction in patients with severe pressure overload hypertrophy.

Blood pressure, cardiac, and renal responses to salt and deoxycorticosterone acetate in mice: role of Renin genes.

Several studies have demonstrated that mice are polymorphic for the number of renin genes, with some inbred strains harboring one gene (Ren-1(c)) and other strains containing two genes (Ren-1(d) and Ren-2). In this study, the effects of 1% salt and deoxycorticosterone acetate (DOCA)/salt were investigated in one- and two-renin gene mice, for elucidation of the role of renin in the modulation of BP, cardiac, and renal responses to salt and DOCA. The results demonstrated that, under baseline conditions, mice with two renin genes exhibited 10-fold higher plasma renin activity, 100-fold higher plasma renin concentrations, elevated BP (which was angiotensin II-dependent), and an increased cardiac weight index, compared with one-renin gene mice (all P &lt; 0.01). The presence of two renin genes markedly increased the BP, cardiac, and renal responses to salt. The number of renin genes also modulated the responses to DOCA/salt. In one-renin gene mice, DOCA/salt induced significant renal and cardiac hypertrophy (P &lt; 0.01) even in the absence of any increase in BP. Treatment with losartan, an angiotensin II AT(1) receptor antagonist, decreased BP in two-renin gene mice but not in one-renin gene mice. However, losartan prevented the development of cardiac hypertrophy in both groups of mice. In conclusion, these data demonstrate that renin genes are important determinants of BP and of the responses to salt and DOCA in mice. The results confirm that the Ren-2 gene, which controls renin production mainly in the submaxillary gland, is physiologically active in mice and is not subject to the usual negative feedback control. Finally, these data provide further evidence that mineralocorticoids promote cardiac hypertrophy even in the absence of BP changes. This hypertrophic process is mediated in part by the activation of angiotensin II AT(1) receptors.

Detection of an asymptomatic right-ventricle cardiac metastasis from a small-cell lung cancer by F-18-FDG PET/CT.

A right heart metastasis of a small-cell lung cancer was found on the whole-body F-fluoro-deoxy-glucose positron emission tomography/computed tomography (F-FDG-PET/CT) of a 69-year-old smoker investigated for a right pulmonary mass discovered on chest radiography after a fracture of the right humerus. The PET scan showed an increased FDG uptake by the mass in the right lung and an intense, atypical focal activity of the right ventricle strongly suggestive of a neoplastic process. CT-guided lung biopsy revealed a small-cell lung cancer and myocardial biopsy confirmed the presence of a cardiac metastasis. The patient was treated with six cycles of chemotherapy followed by radiation therapy, which included the heart lesion. At follow-up PET/CT 2 months after the end of treatment, the abnormal cardiac uptake had disappeared, whereas increased FDG uptake persisted in the pulmonary residual mass.

Endogenous protease nexin-1 protects against cerebral ischemia.

The serine protease thrombin plays a role in signalling ischemic neuronal death in the brain. Paradoxically, endogenous neuroprotective mechanisms can be triggered by preconditioning with thrombin (thrombin preconditioning, TPC), leading to tolerance to cerebral ischemia. Here we studied the role of thrombin's endogenous potent inhibitor, protease nexin-1 (PN-1), in ischemia and in tolerance to cerebral ischemia induced by TPC. Cerebral ischemia was modelled in vitro in organotypic hippocampal slice cultures from rats or genetically engineered mice lacking PN-1 or with the reporter gene lacZ knocked into the PN-1 locus PN-1HAPN-1-lacZ/HAPN-1-lacZ (PN-1 KI) exposed to oxygen and glucose deprivation (OGD). We observed increased thrombin enzyme activity in culture homogenates 24 h after OGD. Lack of PN-1 increased neuronal death in the CA1, suggesting that endogenous PN-1 inhibits thrombin-induced neuronal damage after ischemia. OGD enhanced β-galactosidase activity, reflecting PN-1 expression, at one and 24 h, most strikingly in the stratum radiatum, a glial cell layer adjacent to the CA1 layer of ischemia sensitive neurons. TPC, 24 h before OGD, additionally increased PN-1 expression 1 h after OGD, compared to OGD alone. TPC failed to induce tolerance in cultures from PN-1(-/-) mice confirming PN-1 as an important TPC target. PN-1 upregulation after TPC was blocked by the c-Jun N-terminal kinase (JNK) inhibitor, L-JNKI1, known to block TPC. This work suggests that PN-1 is an endogenous neuroprotectant in cerebral ischemia and a potential target for neuroprotection.

From evidence to clinical practice: effective implementation of therapeutic hypothermia to improve patient outcome after cardiac arrest.

OBJECTIVES: Therapeutic hypothermia has been recommended for postcardiac arrest coma due to ventricular fibrillation. However, no studies have evaluated whether therapeutic hypothermia could be effectively implemented in intensive care practice and whether it would improve the outcome of all comatose patients with cardiac arrest, including those with shock or with cardiac arrest due to nonventricular fibrillation rhythms. DESIGN: Retrospective study. SETTING: Fourteen-bed medical intensive care unit in a university hospital. PATIENTS: Patients were 109 comatose patients with out-of-hospital cardiac arrest due to ventricular fibrillation and nonventricular fibrillation rhythms (asystole/pulseless electrical activity). INTERVENTIONS: We analyzed 55 consecutive patients (June 2002 to December 2004) treated with therapeutic hypothermia (to a central target temperature of 33 degrees C, using external cooling). Fifty-four consecutive patients (June 1999 to May 2002) treated with standard resuscitation served as controls. Efficacy, safety, and outcome at hospital discharge were assessed. Good outcome was defined as Glasgow-Pittsburgh Cerebral Performance category 1 or 2. MEASUREMENTS AND MAIN RESULTS: In patients treated with therapeutic hypothermia, the median time to reach the target temperature was 5 hrs, with a progressive reduction over the 18 months of data collection. Therapeutic hypothermia had a major positive impact on the outcome of patients with cardiac arrest due to ventricular fibrillation (good outcome in 24 of 43 patients [55.8%] of the therapeutic hypothermia group vs. 11 of 43 patients [25.6%] of the standard resuscitation group, p = .004). The benefit of therapeutic hypothermia was also maintained in patients with shock (good outcome in five of 17 patients of the therapeutic hypothermia group vs. zero of 14 of the standard resuscitation group, p = .027). The outcome after cardiac arrest due to nonventricular fibrillation rhythms was poor and did not differ significantly between the two groups. Therapeutic hypothermia was of particular benefit in patients with short duration of cardiac arrest (<30 mins). CONCLUSIONS: Therapeutic hypothermia for the treatment of postcardiac arrest coma can be successfully implemented in intensive care practice with a major benefit on patient outcome, which appeared to be related to the type and the duration of initial cardiac arrest and seemed maintained in patients with shock.

Atypical Kawasaki disease with peripheral gangrene and myocardial infarction: therapeutic implications.

We describe a 2-month-old girl with atypical Kawasaki disease (KD) complicated by peripheral gangrene and myocardial infarction. Peripheral ischaemia leading to gangrene is a rare but serious complication of KD in infants younger than 7 months of age. Treatment has been targeted at reducing arterial inflammation, arteriospasm and thrombosis. We report the first patient with incomplete KD and peripheral ischaemia in whom therapy with prostaglandin E1 (PGE1) as vasodilating and antithrombotic agent appeared successful, restoring hand and foot perfusion without significant long-term sequelae. However, PGE1 could have supported development of myocardial infarction by shunting blood away from ischaemic areas distal to a giant coronary artery aneurysm with beginning thrombosis. CONCLUSION. Atypical KD with peripheral gangrene appears to react favourably to treatment with PGE1, but needs careful monitoring to detect early signs of cardiac ischaemia.

No association between herpes simplex virus 1 and cardiac myxoma.

PRINCIPLES: Cardiac myxoma is the most commonly diagnosed cardiac tumour. Infection of herpes simplex virus 1 (HSV1) has been postulated to be a factor for this pathologic entity. The aim of the current study was to evaluate the association between HSV 1 and myxoma occurrence.METHODS: Between 1965 and 2005, 70 patients (36 female, mean age: 52.6 years) underwent a resection of myxoma. Selected variables such as hospital mortality and morbidity were studied. A follow-up (FU; mean FU time: 138 +/- 83 months) was obtained (76% complete). Immunohistological studies with monoclonal antibodies against HSV type 1 were performed on tumour biopsies of 40 patients.RESULTS: The mean age was 53 +/- 16 years (range 23 to 84 years, 51% female). Of the investigated population, 31 (44%) were in New York Heart Association (NYHA) class III-IV. Mitral valve stenosis was identified in 14 patients (20%), and in 25 (36%) patients mitral valve was insufficient. During hospitalisation 3 patients suffered from a transient neurological disorder, and in addition to myxoma resection 18 (25.7%) patients had to undergo an additional intervention. The overall survival rate was 91% at 40 years. There was no early postoperative mortality in follow-up, although 4 patients died and 2 patients had been re-operated on for recurrent myxomas after 2 and 9 years. Immunohistology revealed no positive signals for HSV-1 antigens among the 40 analysed cases.CONCLUSION: Complete surgical resection, septum included, was the treatment of choice and mandatory to prevent relapse. Peri-operative morbidity and mortality over 40 years remained low, and no association between HSV infection and occurrence of cardiac myxoma was found.

Cardiovascular Pathology. 004. Pathomorphological and CT-angiographical characteristics of coronary atherosclerotic plaques in cases of sudden cardiac death

Objective. The goal of this study was to present the pathological and radiological patterns of "vulnerable" atherosclerotic plaques in cases of sudden cardiac death. Method. This retrospective study was performed on forensic cases for which the cause of death was attributed to coronary artery disease. A complete autopsy was performed in all cases, along with either post-mortem CT-angiography, toxicological analyses and/or biochemistry. Results. 89 cases were selected (mean age 55±11.6 years; 75 men and 14 women). In 96.6% of cases a CT-angiography was performed. Acute coronary lesions were found in 60 cases (mean age 53±11.1 years), which included plaque erosion in 26 cases (mean age 47±8.3 years) and ruptures or intraplaque hemorrhage in 33 cases (mean age 58±10.4 years). Erosions were most frequently found in the left ascending artery (61.5 %), while only 36% of ruptures were observed in this artery. Chronic coronary pathology was described in 30 cases (mean age 58±10.4 years). CT-angiographies performed prior to the autopsy enabled an initial evaluation of coronary artery perfusion. Conclusion. In the face of decreasing clinical autopsy rates, postmortem studies on forensic autopsies, including modern radiological examinations, allow for a more thorough understanding of the clinical picture of disease which can result in sudden cardiac death.