Myocardial T-Lymphocytes as a Prognostic Risk-Stratifying Marker of Dilated Cardiomyopathy　- Results of the Multicenter Registry to Investigate Inflammatory Cell Infiltration in Dilated Cardiomyopathy in Tissues of Endomyocardial Biopsy (INDICATE Study).

BACKGROUND: Dilated cardiomyopathy (DCM) associated with inflammation is diagnosed by endomyocardial biopsy; patients with this have a poorer prognosis than patients without inflammation. To date, standard diagnostic criteria have not been established.Methods and Results: This study analyzed clinical records and endomyocardial biopsy samples of 261 patients with DCM (201 males, median left ventricular ejection fraction; 28%) from 8 institutions in a multicenter retrospective study. Based on the European Society of Cardiology criteria and CD3 (T-lymphocytes) and CD68 (macrophages) immunohistochemistry, 48% of patients were categorized as having inflammatory DCM. For risk-stratification, we divided patients into 3 groups using Akaike Information Criterion/log-rank tests, which can determine multiple cut-off points: CD3+-Low, <13/mm2(n=178, 68%); CD3+-Moderate, 13-24/mm2(n=58, 22%); and CD3+-High, ≥24/mm2(n=25, 10%). The survival curves for cardiac death or left ventricular assist device implantation differed significantly among the 3 groups (10-year survival rates: CD3+-Low: 83.4%; CD3+-Moderate: 68.4%; CD3+-High: 21.1%; Log-rank P<0.001). Multivariate Cox analysis revealed CD3+count as a potent independent predictive factor for survival (fully adjusted hazard ratio: CD3+-High: 5.70, P<0.001; CD3+-Moderate: 2.64, P<0.01). CD3+-High was also associated with poor left ventricular functional and morphological recovery at short-term follow up. CONCLUSIONS: Myocardial CD3+T-lymphocyte infiltration has a significant prognostic impact in DCM and a 3-tiered risk-stratification model could be helpful to refine patient categorization.

A New Mouse Model of Chronic Myocarditis Induced by Recombinant Bacille Calmette-Guèrin Expressing a T-Cell Epitope of Cardiac Myosin Heavy Chain-α.

Dilated cardiomyopathy (DCM) is a potentially lethal disorder characterized by progressive impairment of cardiac function. Chronic myocarditis has long been hypothesized to be one of the causes of DCM. However, owing to the lack of suitable animal models of chronic myocarditis, its pathophysiology remains unclear. Here, we report a novel mouse model of chronic myocarditis induced by recombinant bacille Calmette-Guérin (rBCG) expressing a CD4+ T-cell epitope of cardiac myosin heavy chain-α (rBCG-MyHCα). Mice immunized with rBCG-MyHCα developed chronic myocarditis, and echocardiography revealed dilation and impaired contraction of ventricles, similar to those observed in human DCM. In the heart, CD62L-CD4+ T cells were increased and produced significant amounts of IFN-γ and IL-17 in response to cardiac myosin. Adoptive transfer of CD62L-CD4+ T cells induced myocarditis in the recipient mice, which indicated that CD62L-CD4+ T cells were the effector cells in this model. rBCG-MyHCα-infected dendritic cells produced proinflammatory cytokines and induced MyHCα-specific T-cell proliferation and Th1 and Th17 polarization. This novel chronic myocarditis mouse model may allow the identification of the central pathophysiological and immunological processes involved in the progression to DCM.

Correction to: Performance of 99mTc-aprotinin scintigraphy for diagnosing light chain (AL) cardiac amyloidosis confirmed by endomyocardial biopsy.

This prospective study was conducted according to the principles outlined within the Declaration of Helsinki, and approved by the Ethics Review Board of National Center for Global Health and Medicine (NCGM-G-00839-01, NCGM-G-00839-02).

Performance of 99mTc-aprotinin scintigraphy for diagnosing light chain (AL) cardiac amyloidosis confirmed by endomyocardial biopsy.

BACKGROUND: Light chain (AL) cardiac amyloidosis is associated with a poor prognosis. Diagnosing at an early stage is critical for treatment and the management of cardiac complication. PURPOSE: We aimed to evaluate the diagnostic performance of 99mTc-aprotinin images in patients with AL cardiac amyloidosis. METHODS AND RESULTS: 99mTc-aprotinin scintigraphy and endomyocardial biopsy were performed in 10 patients with suspected amyloidosis. Endomyocardial biopsy showed amyloid deposits in 5 of 10 patients. 99mTc-aprotinin (planer image) was positive in 4 of 5 patients who had amyloid deposits in endomyocardial biopsy. On the other hand, all 5 patients without amyloid deposits were negative in planer image. 99mTc-aprotinin (SPECT/CT image) was positive in all 5 patients who had amyloid deposits. CONCLUSIONS: 99mTc-aprotinin scintigraphy is valuable for the non-invasive diagnosis of AL cardiac amyloidosis.

Radionuclide Imaging of Cardiac Amyloidosis and Sarcoidosis: Roles and Characteristics of Various Tracers.

Amyloidosis and sarcoidosis are systemic diseases that affect multiple organ systems. Accurate diagnosis of cardiac amyloidosis and sarcoidosis is particularly important because cardiac involvement can be fatal. Amyloidosis is characterized by the deposition of amyloid fibrils, and cardiac amyloidosis is classified into amyloid immunoglobulin light chain (AL) and amyloid transthyretin (ATTR) types. Radionuclide tracers for amyloidosis include (a) bone tracers, (b) amyloid-directed molecules, and (c) PET amyloid agents. Bone tracers are particularly sensitive in detection of ATTR type amyloidosis, whereas PET amyloid agents show a higher affinity for the AL type. In sarcoidosis, gallium 67 (67Ga) citrate scintigraphy and fluorine 18 (18F) fluorodeoxyglucose (FDG) PET are pivotal to diagnosis of cardiac sarcoidosis, and 18F-FDG PET/CT has particularly high efficacy in detection of sarcoidosis and monitoring of response to therapy. A major limitation of 18F-FDG is physiologic uptake in the myocardium, which can remain in approximately 20% of patients even after elaborate preparation (eg, prolonged fasting >12-18 hours, modification to a high-fat and low-carbohydrate diet, and injection of unfractionated heparin). This limitation has led to a search for potential new tracers. Recently introduced tracers that show promise include those used in somatostatin receptor imaging and cellular proliferation imaging, which provide detectability as high as that for 18F-FDG without requiring dietary restrictions and have potential for monitoring disease activity. ©RSNA, 2020.

Postconditioning Accelerates Myocardial Inflammatory Resolution Demonstrated by 14C-Methionine Imaging and Attenuates Ventricular Remodeling After Ischemia and Reperfusion.

BACKGROUND: Methionine uptake after myocardial infarction has been proven to reflect myocardial inflammation. The effect of postconditioning on the post-infarction inflammatory process, however, remains to be elucidated.Methods and Results:In control (n=22) and postconditioning rats (n=23), the left coronary artery was occluded for 30 min, followed by reperfusion for 1, 3, 7, and 14 days. Postconditioning was performed immediately following the reperfusion. 14C-methinine (0.74 MBq) and 201Tl (14.8 MBq) were injected 20 and 10 min prior to sacrifice, respectively. One minute before sacrifice, 150-180 MBq of 99 mTc-MIBI was injected immediately following the re-occlusion of the left coronary artery to verify the area at risk, and left ventricular triple-tracer autoradiography was performed. To examine the ventricular remodeling, echocardiography was performed 2 months after reperfusion in both groups (n=6 each). In the control rats, the methionine uptake ratios on days 1, 3, 7, and 14 were 0.74±0.12, 1.85±0.16, 1.48±0.10, 1.25±0.04, respectively. With postconditioning, methionine uptake was similar on day 3 (1.90±0.21), but was lower on day 7 (1.23±0.22, P<0.05) and day 14 (1.08±0.09, P<0.005). Echocardiography revealed that postconditioning reduced the ventricular end-diastolic (0.97±0.16 to 0.78±0.12 cm, P<0.05) and systolic (0.85±0.21 to 0.55±0.23 cm, P<0.05) dimensions and improved ventricular percentage fractional shortening (12±6.2 to 29±12 %, P=0.01). CONCLUSIONS: 14C-methinine imaging revealed that postconditioning accelerated resolution of inflammation and attenuated ventricular remodeling.

A multicenter trial of extracorporeal cardiac shock wave therapy for refractory angina pectoris: report of the highly advanced medical treatment in Japan.

We have previously demonstrated that cardiac shock wave therapy (CSWT) effectively improves myocardial ischemia through coronary neovascularization both in a porcine model of chronic myocardial ischemia and in patients with refractory angina pectoris (AP). In this study, we further addressed the efficacy and safety of CSWT in a single-arm multicenter study approved as a highly advanced medical treatment by the Japanese Ministry of Health, Labour and Welfare. Fifty patients with refractory AP [mean age 70.9 ± 12.6 (SD) years, M/F 38/12] without the indications of percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG) were enrolled in 4 institutes in Japan. Ischemic myocardial regions in the left ventricle (LV) were identified by drug-induced stress myocardial perfusion imaging (MPI). Shock waves (200 shots/spot at 0.09 mJ/mm2) were applied to 40-60 spots in the ischemic myocardium 3 times in the first week. The patients were followed up for 3 months thereafter. Forty-one patients underwent CSWT and completed the follow-up at 3 months. CSWT markedly improved weekly nitroglycerin use [from 3.5 (IQR 2 to 6) to 0 (IQR 0 to 1)] and the symptoms [Canadian Cardiovascular Society functional class score, from 2 (IQR 2 to 3) to 1 (IQR 1 to 2)] (both P < 0.001). CSWT also significantly improved 6-min walking distance (from 384 ± 91 to 435 ± 122 m, P < 0.05). There were no significant changes in LV ejection fraction evaluated by echocardiography and LV stroke volume evaluated by cardiac magnetic resonance imaging (from 56.3 ± 14.7 to 58.8 ± 12.8%, P = 0.10, and from 52.3 ± 17.4 to 55.6 ± 15.7 mL, P = 0.15, respectively). Percent myocardium ischemia assessed by drug-induced stress MPI tended to be improved only in the treated segments (from 16.0 ± 11.1 to 12.1 ± 16.2%, P = 0.06), although no change was noted in the whole LV. No procedural complications or adverse effects related to the CSWT were noted. These results of the multicenter trial further indicate that CSWT is a useful and safe non-invasive strategy for patients with refractory AP with no options of PCI or CABG.

Successful Inflammation Imaging of Non-Human Primate Hearts Using an Antibody Specific for Tenascin-C.

Inflammation after myocardial infarction (MI) may be a major factor influencing ventricular remodeling, leading to congestive heart failure and arrhythmia. Therefore, inflammation in the heart needs to be monitored. Tenascin-C (TNC) is an extracellular matrix molecule not normally expressed, but it is strongly upregulated when associated with active inflammation. Based on this characteristic, we successfully imaged in vivo inflammatory lesions in rat models using 111Indium (111In)-labeled anti-TNC antibodies. The aim of the present study was to further assess the applicability of this molecular imaging probe to detect inflammatory activity in primate hearts.We generated an MI model of cynomolgus monkeys (Macaca fascicularis) by coronary artery ligation and performed dual-isotope single-photon emission computed tomography (SPECT) imaging with an 111In-labeled anti-TNC antibody Fab' fragment (111In-TNC Fab') and 99mtechnetium methoxy-isobutyl isonitrile (99mTc-MIBI). Dual autoradiography was used to compare the uptake of 111In-TNC Fab' with histology and immunostaining for TNC. Dual-isotope SPECT showed the regional myocardial uptake of 111In-TNC Fab' complementary to a defect in the perfusion image by 99mTc-MIBI. The high radioactivity of 111In-TNC Fab' by autoradiography corresponded to immunostaining for TNC, which was observed in inflammatory lesions at the border zone between the infarcted and non-infarcted areas of the left ventricle and at the epi/pericarditis lesions of the right ventricle. These results demonstrate the potential of 111In-TNC-Fab' imaging to monitor myocardial injury and inflammation and suggest the feasibility of the non-invasive detection of cardiac inflammation following acute MI in a preclinical stage before testing in humans.

Serum Tenascin-C as a Novel Predictor for Risk of Coronary Artery Lesion and Resistance to Intravenous Immunoglobulin in Kawasaki Disease　- A Multicenter Retrospective Study.

BACKGROUND: Tenascin-C (TN-C) is an extracellular matrix glycoprotein that is heavily upregulated at sites of inflammation. We conducted a retrospective study to assess the utility of TN-C as a novel biomarker to predict the risk of developing coronary artery lesions (CAL) and resistance to intravenous immunoglobulin (IVIG) in patients with Kawasaki disease (KD).Methods and Results:We collected blood samples of 111 KD patients (IVIG-responder: 89, IVIG-resistant: 22; CAL: 8) and 23 healthy controls, and measured the serum levels of TN-C. TN-C levels on admission were significantly higher in patients than in healthy controls and in patients during convalescence after IVIG administration (69.6 vs. 20.4 vs. 39.7 ng/ml, respectively; P<0.001), and correlated positively with C-reactive protein (P<0.001), neutrophil (percentage; P=0.005), and ALT (P<0.001), and negatively with platelet count (P=0.023) and sodium level (P=0.025). On admission, TN-C levels in patients who later developed CAL were significantly higher than in those without CAL (P=0.010), and significantly higher in IVIG-resistant subjects than in IVIG-responders (P=0.003). The accuracy of TN-C testing for the prediction of IVIG resistance was comparable to that of the Kobayashi score. CONCLUSIONS: Serum TN-C could be a biomarker for predicting the risk of developing CAL and IVIG resistance during the acute phase of KD. (Circ J 2016; 80: 2376-2381).

Suppressor of cytokine signaling 1 DNA administration inhibits inflammatory and pathogenic responses in autoimmune myocarditis.

Myocarditis and subsequent dilated cardiomyopathy are major causes of heart failure in young adults. Myocarditis in humans is highly heterogeneous in etiology. Recent studies have indicated that a subgroup of myocarditis patients may benefit from immune-targeted therapies, because autoimmunity plays an important role in myocarditis as well as contributing to the progression to cardiomyopathy and heart failure. Suppressor of cytokine signaling (SOCS) 1 plays a key role in the negative regulation of both TLR- and cytokine receptor-mediated signaling, which is involved in innate immunity and subsequent adaptive immunity. In this study, we investigated the therapeutic effect of SOCS1 DNA administration on experimental autoimmune myocarditis (EAM) in mice. EAM was induced by s.c. immunization with cardiac-specific peptides derived from α myosin H chain in BALB/c mice. In contrast to control myocarditis mice, SOCS1 DNA-injected mice were protected from development of EAM and heart failure. SOCS1 DNA administration was effective for reducing the activation of autoreactive CD4(+) T cells by inhibition of the function of Ag-presenting dendritic cells. Our findings suggest that SOCS1 DNA administration has considerable therapeutic potential in individuals with autoimmune myocarditis and dilated cardiomyopathy.

Pitavastatin regulates helper T-cell differentiation and ameliorates autoimmune myocarditis in mice.

PURPOSE: Experimental autoimmune myocarditis (EAM) is a mouse model of inflammatory cardiomyopathy, and the involvement of T helper (Th) 1 and Th17 cytokines has been demonstrated. Accumulated evidence has shown that statins have anti-inflammatory and immunomodulatory effects; however, the mechanism has not been fully elucidated. This study was designed to test the hypothesis that pitavastatin affects T cell-mediated autoimmunity through inhibiting Th1 and Th17 responses and reduces the severity of EAM in mice. METHODS: The EAM model was established in BALB/c mice by immunization with murine α-myosin heavy chain. Mice were fed pitavastatin (5 mg/kg) or vehicle once daily for 3 weeks from day 0 to day 21 after immunization. RESULTS: Pitavastatin reduced the pathophysiological severity of the myocarditis. Pitavastatin treatment inhibited the phosphorylation of signal transducer and activator of transcription (STAT)3 and STAT4, which have key roles in the Th1 and Th17 lineage commitment, respectively, in the heart, and suppressed production of Th1 cytokine interferon-γ and Th17 cytokine interleukin-17 from autoreactive CD4(+) T cells. In in vitro T-cell differentiation experiments, pitavastatin-treated T cells failed to differentiate into Th1 and Th17 cells through inhibiting the transcription of T-box expressed in T-cells (T-bet) and RAR-related orphan receptor γt (RORγT) which have critical roles in the development of Th1 and Th17 cells, respectively, and this failure was rescued by adding mevalonate. CONCLUSIONS: Pitavastatin inhibits Th1 and Th17 responses and ameliorates EAM. These results suggest that statins may be a promising novel therapeutic strategy for the clinical treatment of myocarditis and inflammatory cardiomyopathy.

Atrial natriuretic peptide exerts protective action against angiotensin II-induced cardiac remodeling by attenuating inflammation via endothelin-1/endothelin receptor A cascade.

We aimed to investigate whether atrial natriuretic peptide (ANP) attenuates angiotensin II (Ang II)-induced myocardial remodeling and to clarify the possible molecular mechanisms involved. Thirty-five 8-week-old male Wistar-Kyoto rats were divided into control, Ang II, Ang II + ANP, and ANP groups. The Ang II and Ang II + ANP rats received 1 µg/kg/min Ang II for 14 days. The Ang II + ANP and ANP rats also received 0.1 µg/kg/min ANP intravenously. The Ang II and Ang II + ANP rats showed comparable blood pressure. Left ventricular fractional shortening and ejection fraction were lower in the Ang II rats than in controls; these indices were higher (P < 0.001) in the Ang II + ANP rats than in the Ang II rats. In the Ang II rats, the peak velocity of mitral early inflow and its ratio to atrial contraction-related peak flow velocity were lower, and the deceleration time of mitral early inflow was significantly prolonged; these changes were decreased by ANP. Percent fibrosis was higher (P < 0.001) and average myocyte diameters greater (P < 0.01) in the Ang II rats than in controls. ANP decreased both myocardial fibrosis (P < 0.01) and myocyte hypertrophy (P < 0.01). Macrophage infiltration, expression of mRNA levels of collagen types I and III, monocyte chemotactic protein-1, and a profibrotic/proinflammatory molecule, tenascin-C (TN-C) were increased in the Ang II rats; ANP significantly decreased these changes. In vitro, Ang II increased expression of TN-C and endothelin-1 (ET-1) in cardiac fibroblasts, which were reduced by ANP. ET-1 upregulated TN-C expression via endothelin type A receptor. These results suggest that ANP may protect the heart from Ang II-induced remodeling by attenuating inflammation, at least partly through endothelin 1/endothelin receptor A cascade.

Prognostic value of serum tenascin-C levels on long-term outcome after acute myocardial infarction.

BACKGROUND: Tenascin-C (TN-C), an extracellular matrix glycoprotein, is not normally expressed in the adult heart but transiently reappears under various pathologic conditions to play important roles in tissue remodeling. It is unclear whether serum TN-C levels add prognostic information independent from traditional prognostic markers. METHODS AND RESULTS: We assessed 239 patients with first ST-segment elevation myocardial infarction who underwent successful percutaneous coronary intervention. We measured serum TN-C and plasma B-type natriuretic peptide (BNP) levels on day 5 after admission and compared long-term clinical outcome. During the follow-up period (24.3 ± 13 months), 54 patients experienced primary composite cardiac events (cardiac death or hospitalization for worsening heart failure). Multivariable Cox proportional hazards analysis indicated that serum TN-C (hazard ratio 2.92, 95% confidence interval [CI] 1.55-5.67; P < .001) and plasma BNP levels (hazard ratio 1.84, 95% CI 1.17-2.97; P = .008) were significant independent predictors for cardiac events after adjustment for multiple confounders. The combination of TN-C and BNP resulted in an increase of the c-statistic from 0.821 to 0.877 (P < .001) and an integrated discrimination improvement gain of 14.0% (P < .001). CONCLUSIONS: Serum TN-C level on day 5 after admission is potentially useful for early risk stratification after AMI beyond established prognostic markers.

Comprehensive assessment of metabolic syndrome among rural Bangladeshi women.

BACKGROUND: Metabolic syndrome (MS), defined as a constellation of cardiovascular disease (CVD) risk factors, is one of the fastest growing public health burdens in the Asia-Pacific region. This trend is despite the fact that people in this region are no more overweight than Europeans and Americans. Unfortunately, in South Asia, MS screening has only been performed in a few countries other than Bangladesh. Therefore the present study is designed to conduct a comprehensive screening of MS in Bangladeshi rural women, which includes estimation of prevalence and assessment of risk factor. METHODS: A total of 1535 rural Bangladesh women aged ≥ 15 years were studied using a population based cross-sectional survey. The prevalence of MS was estimated using NCEP ATP III, modified NCEP ATP III and IDF criteria. RESULTS: The prevalence rates of MS were 25.60% (NCEP ATP III), 36.68% (modified NCEP ATP III), and 19.80% (IDF), as revealed by the present study. Furthermore, based on the NCEP ATP III criteria, 11.60% of the subjects were found to have excess waist circumference; 29.12% had elevated blood pressure, 30.42% had elevated fasting plasma glucose level, 85.47% had low HDL values and 26.91% had increased triglyceride values. Low plasma HDL level was found to be the most common abnormality in the target population and elevated waist circumference was the least frequent component. CONCLUSIONS: The present study reveals a high prevalence of MS and its associated risk factors in rural Bangladeshi women. These findings are important in that they provide insights that will be helpful in formulating effective public health policy, notably the development of future health prevention strategies in Bangladesh.

Role of coronary CT angiography in asymptomatic patients with type 2 diabetes mellitus.

Diabetic patients with coronary artery disease are often asymptomatic, making appropriate care of such patients difficult. The purpose of this study was to investigate the prevalence of coronary lesions in asymptomatic diabetic patients. Coronary computed tomography (CT) angiography was performed in 120 consecutive diabetic patients (90 of whom were men, mean age 65, mean HbA1c 7.2%). Images from patients whose coronary artery calcium scores (CAC scores) were less than 400 were subjected to stenosis and plaque analysis. Significant stenosis was defined as coronary artery stenosis > 70%. High-risk plaque was defined as plaque having both a CT density < 30 Hounsfield Units (HU) and showing positive remodeling. Significant stenoses were identified in 30.5% of the patients. High-risk plaques were identified in 17.1% of the patients. Less than half of the high-risk plaques were obstructive plaques. There was a statistically significant association between significant stenosis and high-risk plaque by chi-square test (P = 0.022). We found significant stenosis even in patients whose CAC score = 0 at a rate of 5.0%. Using univariate logistic-regression analysis, we found that coronary risk factors associated with significant stenosis and high-risk plaque were dyslipidemia (P = 0.033) and current smoking (P = 0.030), respectively. We report for the first time, the prevalence of high-risk plaques in the arteries of patients with asymptomatic diabetes, as assessed by coronary CT angiography.

Effects of anemia correction by erythropoiesis-stimulating agents on cardiovascular function in non-dialysis patients with chronic kidney disease.

Anemia is a significant risk factor for patients with chronic kidney disease (CKD). Here, we investigated the effects of anemia correction on cardiac functions in CKD patients. Pre-dialysis CKD patients (n = 171) without known risk factors for cardiovascular disease (CVD) other than CKD with hemoglobin (Hb) concentrations < 10.0 g/dL were enrolled for evaluation of cardiac functions and biomarkers before and after the 16-week treatment of erythropoiesis-stimulating agents. The treatment significantly increased Hb concentrations in all patients who completed the study (n = 143, 8.91 ± 0.87 versus 11.27 ± 1.31 g/dL; n < 0.001) and among patients whose echocardiograms were available for evaluation (n = 77, 8.92 ± 0.94 versus 11.24 ± 1.13 g/dL; P < 0.001). The left ventricular mass index (LVMI) was decreased (121.3 ± 25.8 versus 114.7 ± 25.1 g/m(2), n = 77, P = 0.012) and significant correlation between the change in the LVMI and Hb concentration was noted (P = 0.011). The levels of B-type natriuretic peptide and human atrial natriuretic peptide, and the cardio-thoracic ratio were significantly increased among subjects with Hb concentrations < 11.0 g/dL at completion of the study. The changes in these parameters were significantly correlated with the Hb concentrations (P = 0.033, P = 0.011, and P < 0.001, respectively). No significant differences were observed in the electrocardiographic parameters. Correcting Hb levels higher than those conventionally recommended reduced left ventricular hypertrophy and myocardial stress, lowering risks for CVD in pre-dialysis CKD patients.

Toward in vivo imaging of heart disease using a radiolabeled single-chain Fv fragment targeting tenascin-C.

Antibodies specific to a particular target molecule can be used as analytical reagents, not only for in vitro immunoassays but also for noninvasive in vivo imaging, e.g., immunoscintigraphies. In the latter case, it is important to reduce the size of antibody molecules in order to achieve suitable in vivo "diagnostic kinetics" and generate higher-resolution images. For these purposes, single-chain Fv fragments (scFvs; M(r) < 30 kDa) have greater potential than intact immunoglobulins (~150 kDa) or Fab (or Fab') fragments (~50 kDa). Our recent observation of enhanced tenascin-C (Tnc) expression at sites of cardiac repair after myocardial infarction prompted us to develop a radiolabeled scFv against Tnc for in vivo imaging of heart disease. We cloned the genes encoding the heavy and light chain variable domains of the mouse anti-Tnc monoclonal antibody 4F10, and combined them to create a single gene. The resulting scFv-4F10 gene was expressed in E. coli cells to produce soluble scFv proteins. scFv-4F10 has an affinity for Tnc (K(a) = 3.5 × 10(7) M(-1)), similar to the Fab fragment of antibody 4F10 (K(a) = 1.3 × 10(7) M(-1)) and high enough to be of practical use. A cysteine residue was then added to the C-terminus to achieve site-specific (111)In labeling via a chelating group. The resulting (111)In-labeled scFv was administered to a rat model of acute myocardial infarction. Biodistribution and quantitative autoradiographic studies indicated higher uptake of the radioactivity at the infarcted myocardium than the noninfarcted one. Single photon emission computed tomography (SPECT) provided in vivo cardiac images that coincided with the ex vivo observations. Our results will promote advances in diagnostic strategies for heart disease.

Tenascin-C is expressed in abdominal aortic aneurysm tissue with an active degradation process.

Abdominal aortic aneurysm (AAA) is a common disease caused by segmental weakening of the aortic walls and progressive aortic dilation leading to the eventual rupture of the aorta. Currently no biomarkers have been established to indicate the disease status of AAA. Tenascin-C (TN-C) is a matricellular protein that is synthesized under pathological conditions. In the current study, we related TN-C expression to the clinical course and the histopathology of AAA to investigate whether the pattern of TN-C expression could indicate the status of AAA. We found that TN-C and matrix metalloproteinase (MMP)-9 were highly expressed in human AAA. In individual human AAA TN-C deposition associated with the tissue destruction, overlapped mainly with the smooth muscle actin-positive cells, and showed a pattern distinct from macrophages and MMP-9. In the mouse model of AAA high TN-C expression was associated with rapid expansion of the AAA diameter. Histological analysis revealed that TN-C was produced mainly by vascular smooth muscle cells and was deposited in the medial layer of the aorta during tissue inflammation and excessive destructive activities. Our findings suggest that TN-C may be a useful biomarker for indicating the pathological status of smooth muscle cells and interstitial cells in AAA.

Case Report: Acute Eosinophilic Myocarditis With a Low-Flow Heart Failure With Preserved Ejection Fraction Phenotype.

Eosinophilic myocarditis is a rare subtype of myocarditis characterized by myocardial eosinophilic infiltration, and it is potentially fatal if left untreated. Although endomyocardial biopsy (EMB) is a cornerstone for the histological diagnosis of acute eosinophilic myocarditis (AEM), as it is an invasive procedure and has a low diagnostic accuracy, the diagnosis of AEM with hemodynamic instability remains challenging. We describe a case of AEM presenting as low-flow heart failure with preserved ejection fraction (HFpEF), with rapid progression to cardiogenic shock. The constellation of peripheral eosinophilia, increased left ventricular wall thickness, and HFpEF raised the suspicion of AEM. Contrast-enhanced computed tomography (CT) scan revealed heterogeneous hypoenhancement localized in the basal-to-mid septal and mid anterolateral walls of the left ventricle, strongly suggestive of acute inflammation. Based upon these findings, we performed CT-guided EMB, which lead to a definitive diagnosis. Subsequent high-dose corticosteroids allowed a rapid and dramatic recovery and normalization of cardiac structure and function. This case highlights the clinical importance of assessing AEM as a rare cause of HFpEF and the usefulness of CT-guided EMB in patients with hemodynamic instability.