Pulmonary expression of inducible heme-oxygenase after ischemia/reperfusion of the lower extremities in rats

BACKGROUND

Expression of inducible heme-oxygenase (HO-1) has been shown to be increased in various inflammatory disorders, which may confer a protective role. The aim of our study was to assess pulmonary expression of HO-1 after ischemia/reperfusion (I/R) of the lower limbs in rats.

MATERIALS AND METHODS

We compared three groups of rats (n = 5/group): one Sham group, and two I/R groups (aorta cross-clamped for 2 h followed by 2 h of reperfusion), one of which pre-treated with Zn-protoporphyrin (Zn-PP), a competitive inhibitor of HO (50 micromol/kg, i.p.). At the end of experiment, lungs were harvested for determination of HO activity and HO-1 expression by Western blot and immunohistochemistry. Lung injury was assessed by bronchoalveolar lavage, histological study, and determination of the lung Evans Blue dye content, an index of microvascular permeability.

RESULTS

I/R of the lower limbs was responsible for acute lung injury (ALI), characterized by neutrophilic infiltration (87 +/- 20 x 10(3) neutrophils/mm(3), Sham group versus 191 +/- 38 x 10(3) neutrophils/mm(3), I/R group; P < 0.002) and an increase in lung Evans blue dye content: (74 +/- 6 microg/g, Sham group versus 122 +/- 48 microg/g, I/R group; P < 0.05). Pre-treatment with Zn-PP further increases the Evans Blue content (122 +/- 48 microg/g, I/R group versus 179 +/- 23 microg/g Zn-PP group P < 0.05) and the neutrophilic infiltration. Pulmonary heme-oxygenase activity, and HO-1 content were increased after I/R. (10.5 +/- 12 pmol bilirubin/mg protein/h, Sham group versus 101.2 +/- 66 pmol bilirubin/mg protein/h, I/R group; P < 0.02). Immunohistochemistry revealed that the expression of HO-1 was mainly localized to inflammatory cells.

CONCLUSIONS

ALI following I/R of the lower limbs in rats is associated with an increase of pulmonary expression of HO-1, inhibition of this expression increase the severity of ALI.

Age and gender effects on apoptosis in the human coronary arterial wall

The relationship between aging and apoptosis remains unclear. We wondered whether apoptosis could be enhanced in arterial aging in the absence of overt or advanced arterial disease. Apoptosis-related proteins were investigated using three methods: TdT-mediated dUTP digoxigenin nick end labeling (TUNEL) technique, active cysteine-dependant aspartate specific proteases (caspase)-3 and poly ADP-ribose polymerase (PARP) in coronary arteries of human subjects ranging from 25 to 92 years. We found no significant correlation between age and the apoptotic index using the three methods. The percentage of active caspase-3 positive cells was found to be significantly higher in men than in women (9.11 +/- 12.3 cells/mm(2) versus 2.01 +/- 4.55 cells/mm(2), respectively, p = 0.017). These sex-related differences did not reach statistical significance using TUNEL (9.93 +/- 17 and 2.61 +/- 4.58 cells/mm(2), p = 0.32) and PARP methods (3.42 +/- 7.74 and 0.86 +/- 0.95 cells/mm(2), p < 0.49). This is the first report of detection of apoptotic cells in the human arterial wall in adult subjects free from arterial diseases. Apoptosis is an attractive hypothesis to account for organ aging, but our study suggests that apoptosis is not a key factor in aging of the arterial wall.

Preliminary ex vivo 3D microscopy of coronary arteries using a standard 1.5 T MRI scanner and a superconducting RF coil

This paper presents the feasibility of three-dimensional (3D) magnetic resonance (MR) histology of atheromatous coronary lesions in the entire human heart ex vivo using a standard 1.5 T scanner and a 12 mm high-temperature superconducting (HTS) surface coil. The HTS coil was a five-turn transmission-line resonator operated at 77 K, affording a signal-to-noise ratio (SNR) gain of about ninefold as compared to a similar, room-temperature copper coil. Local microscopy at the surface of an explanted, entire heart was achieved by a 3D spoiled gradient echo sequence and assessed by comparison with conventional histology. One hundred and twenty four adjacent cross sections of the coronary artery, with voxels of 59 x 59 x 100 microm3 and an SNR of about 20, were obtained in 25 min. Consecutive data sets were combined to reconstruct extended views along the artery. Compared to histology, MR microscopy allowed precise nondestructive 3D depiction of the architecture of the atheromatous plaques. This is the first report of microscopic details (less than 10(-3) mm3 voxels) of diseased arteries obtained in an entire human heart preserving the arterial integrity and the spatial geometry of atheroma. This noninvasive microscopy approach using a HTS surface coil might be applied in vivo to study the architecture and components of superficial human structures, using routine MR scanners.

[Arrhythmogenic right ventricular dysplasia]

Congestive cardiac failure could be as important as cardiac arrhythmias in the natural history of arrhythmogenic right ventricular dysplasia. This can be related to the progressive replacement of myocardium by fat and fibrosis of the right ventricle. The left ventricle may also be involved by the same disease process. Moreover, inflammation can be superimposed on ARVD, resulting in a wide spectrum of clinical presentation which can mimick idiopathic dilated cardiomyopathy. Right ventricular cardiac failure has been controlled by anterior dynamic cardiomyoplasty.

Acute vascular humoral rejection in a sensitized cardiac graft recipient: diagnostic value of C4d immunofluorescence

A 37-year-old female patient had a cardiac transplantation for dilated cardiomyopathy. She was sensitized by two pregnancies showing anti-human leukocyte antigen I and II antibodies. The pretransplantation crossmatch was negative, but she developed acute humoral rejection characterized by vascular C4d deposits, arteriolitis, and intravascular leukocyte accumulation and adhesion in venules. Although C4d deposits disappeared in 4 weeks, she had persistent endothelial cell activation (endothelial expression of ELAM-1, VCAM-1, or human leukocyte antigen class II) throughout the 6 months of follow-up. Although she received intensive immunosuppression, she presented three episodes of acute cellular rejection during that period of time. This case shows that C4d deposits represent a sensitive marker of acute humoral rejection in cardiac transplantation. Therefore, C4d immunofluorescence should be more frequently assessed in endomyocardial biopsies.

Fulminant invasive pulmonary aspergillosis in immunocompetent patients--a two-case report

Two cases of invasive aspergillosis (IA) in immunocompetent patients with a fulminant fatal outcome are reported. Both patients were elderly and had a history of chronic lung disease treated with prolonged inhaled corticosteroids and a short course of systemic corticosteroids. They presented with dyspnea and fever, their respiratory function deteriorated rapidly, and they died 7 days after admission. Aspergillus fumigatus was cultured from respiratory samples. IA was confirmed in one case by necropsy that showed diffuse bilateral necrotizing pneumonitis and myocarditis. In the other case, IA diagnosis was established by thoracic CT scan plus detection of Aspergillus antigen in two blood samples. These two cases demonstrate that short-term corticosteroid therapy in immunocompetent patients with underlying chronic lung conditions is a risk factor for IA, and that its evolution can be fulminant.

Myocarditis associated with Hashimoto’s disease: a case report

We report on a sudden cardiac death case involving a 40-year-old man with no known medical history. Forensic autopsy showed lymphocytic myocarditis associated with lymphocytic thyroiditis. In both the heart and the thyroid gland, the inflammatory foci often had a nodular pattern with a germinal centre. Virological and toxicological analyses were negative. Postmortem biochemistry showed a slight increase in TSH in combination with normal T3 and T4 blood levels suggesting hypothyroidism. High titres of antiperoxidase and antithyroglobulin antibodies with normal levels of TSH receptor antibodies, in addition to biological hypothyroidism and lymphocytic inflammation were consistent with the diagnosis of Hashimoto's thyroiditis. Immunohistochemical studies excluded a lymphoma and showed no evidence of viral myocarditis. In contrast to Grave's disease, Hashimoto's thyroiditis has never been reported in association with myocarditis as a cause of sudden death. We conclude that the cardiac immunological and histological pattern, similar to that found in the thyroid gland suggests an autoimmune myocarditis.

Effects of angiotensin II type 1 receptor blockade in ApoE-deficient mice with post-ischemic heart failure

We investigated in mice whether atherosclerosis exacerbates the development of post-ischemic heart failure and alters the beneficial effects of long-term angiotensin II type 1 receptor blockade in this model. ApoE-deficient (ApoE(-/-)) and C57BL/6J (C57) mice with myocardial infarction (coronary ligation) received vehicle (C57 and ApoE(-/-)) or irbesartan (Ir, 50mg/kg/d orally, C57-Ir and ApoE(-/-)-Ir). Ten months post myocardial infarction, survival rates were similar in C57 (58%) and ApoE(62%). Atherosclerosis induced no significant alteration in blood pressure, cardiac output (fluospheres), total peripheral resistance, or shortening fraction (echocardiography) but increased renal resistance (+50%, P<0.05). Chronic Ir treatment significantly improved survival to a similar extent in both C57-Ir (85%) and ApoE(-/-)-Ir (86%). It also decreased blood pressure to a similar extent in both strains (-16% and -18%, both P<0.05). In C57-Ir mice, Ir did not modify cardiac output or total peripheral resistance, but it decreased renal resistance (-28%, P<0.001) and left-ventricular weight (-28%, P<0.05). In ApoE(-/-)-Ir mice, Ir limited atherosclerotic lesions (-13%, P<0.05), increased cardiac output (+28%, P<0.05) and shortening fraction (+24%, P<0.05), and decreased total peripheral resistance (-33%, P<0.01), renal resistance (-61%, P<0.001), and left-ventricular weight (-27%, P<0.001). In conclusion, atherosclerosis does not worsen heart failure development in mice and, although the beneficial cardiovascular effects of AT1 receptor blockade are greater in ApoE(-/-) than in C57, reduction in mortality is similar in both strains.

Long-term evaluation of the replacement of the trachea with an autologous aortic graft

BACKGROUND

Tracheal reconstruction after extensive resection remains a challenge in thoracic surgery. The goal of this experimental study was to analyze the long-term evolution of tracheal replacement using an autologous aortic graft.

METHODS

In 21 sheep, a 5-cm segment of the cervical trachea was replaced by a segment of the descending thoracic aorta that was reconstructed to a prosthetic graft. Because of the airway collapse reported in a previous series, a permanent (n = 13) or temporary (n = 8) stent was systematically placed in the lumen of the graft. Clinical, bronchoscopic, and histologic examinations were performed up to 3 years after implantation.

RESULTS

All animals survived the operation with no paraplegia. In the group with a permanent stent, three complications occurred: one stent displacement, one laryngeal edema, and one infection. Stent removal was tolerated after 6 months in the group with a temporary stent. Histologic examination showed a progressive transformation of the arterial segment into first extensive inflammatory tissue with a squamous epithelium, and after 6 to 36 months well-differentiated tracheal tissue including a continuous mucociliary epithelium and regular rings of newly formed cartilage.

CONCLUSIONS

An autologous aortic graft used as a substitute for extensive tracheal replacement in sheep remained functional for periods up to 3 years. The progressive transformation of the graft into a structure resembling tracheal tissue seems to be a key factor in long-term patency. The mechanism of this regenerative process and the possibility of using arterial homografts, which would make clinical application easier, remain to be evaluated.

Pathology of sudden death during recreational sports activity: an autopsy study of 31 cases

A growing number of people are involved in recreational physical activity. It is therefore not uncommon for a medical examiner to encounter sports-related sudden deaths and to be faced with the legal implications. The authors examined the clinical and cardiac pathologic patterns in 31 persons who died suddenly during sports activities and underwent autopsy at the Institute of Forensic Medicine of Paris between 1991 and 2001. Twenty-nine male subjects, ranging in age from 7 to 57 years (mean 30 years) and two female subjects, 8 and 60 years old, died suddenly during sports activities. The sports involved were various, with running the most frequent: 13 cases. Cardiomyopathies (10 cases) and coronary artery disease (9 cases) were the most frequent causes of deaths. Despite the severity of lesions, only 4 subjects had a known cardiovascular disease. In conclusion, with regard to prevention, efforts should be continued to improve the sensitivity and specificity of diagnostic tools and screening strategies. In this regard, medicolegal autopsies should be systematically performed in cases of sudden death during sports activities, because they provide accurate and useful information for a better knowledge of sports-related mortality.

Growth factors improve latissimus dorsi muscle vascularization and trophicity after cardiomyoplasty

BACKGROUND

Dynamic cardiomyoplasty consists of wrapping the electrostimulated latissimus dorsi muscle (LDM) around the failed heart. Partial ischemia followed by atrophy of the middle and distal part of the LDM were observed in 30% of clinical cases after LDM flap elevation from its origin. In the current study, we hypothesized that local administration of growth factors at the LDM/epicardial interface could improve muscle vascularization and trophicity.

METHODS

In 24 sheep, dynamic cardiomyoplasty was performed using the left LDM. A multiperforated catheter was positioned at the LDM/epicardial interface for a weekly administration, during a 1-month period, of the following factors: basic fibroblast growth factor (bFGF, n = 6), vascular endothelial growth factor (VEGF, n = 6), and regenerating agent (RGTA, n = 6). Six sheep injected with phosphate-buffered saline (used for dilution of the growth factors) were used as a control group. At 3 months, angiographic, histologic, and histomorphometric studies were performed.

RESULTS

Angiographic studies of the animals treated with growth factors demonstrated hypervascularization due to the development of new vessels. Histomorphometric and histologic studies showed a significant increase in the number of capillaries and arterioles (100 fields/muscle) in the groups treated with bFGF (443.0 +/- 101.2, p < 0.01), RGTA (293.2 +/- 29.3, p < 0.05), and VEGF (246.5 +/- 45.9, p < 0.05), as compared with the control group (81.5 +/- 11.4). A significantly lower atrophy score was observed in the groups treated with bFGF (1.4 +/- 0.18, p < 0.05), RGTA (1.59 +/- 0.17, p < 0.05), and VEGF (1.96 +/- 0.14, NS), as compared with the control group (2.48 +/- 0.16).

CONCLUSIONS

Local administration at the heart/muscle interface of growth factors increases muscle vascularization and avoids muscle atrophy in an experimental cardiomyoplasty model, both of which are advantageous to the contracting LDM. The local growth factors delivery system used in this study appears efficient, easy to implant, and manipulate and safe.

Survival, haemodynamics and cardiac remodelling follow up in mice after myocardial infarction

1. In the present study, the time-course, over a 1 year period, of postischaemic dilated cardiomyopathy and/or development of congestive heart failure was investigated in mice in terms of survival and cardiac functional and structural characteristics. 2. C57BL/6 mice with myocardial infarction (MI mice; coronary ligation n = 78) or sham-operated animals (n = 45) were used and echocardiographic, haemodynamic and histomorphometric parameters were assessed at 3, 6 and 12 months post-MI. 3. At 12 months, the survival rate was 70% in MI mice. Left ventricular dysfunction was evidenced by a strong decrease in ejection fraction (EF; -48 and -53% at 6 and 12 months, respectively; both P < 0.05) and an increase in left ventricular end-diastolic pressure (+100% at both 6 and 12 months; both P < 0.05). There was no major worsening in cardiac function between 6 and 12 months, suggesting strong compensatory mechanisms. Cardiac remodelling was observed, characterized by strong left ventricular hypertrophy (+38 and +62% at 6 and 12 months, respectively; both P < 0.05) and dilatation (+53% at 6 months; P < 0.05), but collagen was not significantly increased. Significant correlations were found between EF (echocardiography) and dP/dtmax, between end-diastolic volume (echocardiography) and left ventricular internal perimeter (histomorphometry) and between left ventricular mass (echocardiography) and weight. 4. In conclusion, despite a high survival rate, the MI mouse model displays most of the hallmarks of postischaemic dilated cardiomyopathy and/or congestive heart failure, thus affording the necessary background for the subsequent evaluation of gene manipulation and/or drug effects. In addition, two-dimensional echocardiography appears to be a suitable tool for the long-term follow up of cardiac function and remodelling in this model.

Intermediate follow-up of a composite stentless porcine valved conduit of bovine pericardium in the pulmonary circulation

BACKGROUND

In the pediatric population, glutaraldehyde-preserved bovine pericardium conduit containing a stentless porcine valve has been proposed as an alternative to homografts for right ventricular outflow tract reconstruction.

METHODS

Between June 1996 and March 2000, a total of 55 patients, 20 with truncus arteriosus, 21 with pulmonary atresia with ventricular septal defect, and 14 with miscellaneous defects, received this conduit. Median age at implantation was 3.4 months (range, 3 days to 19 years), and 27 patients (50%) were less than 3 months old. Clinical outcome, echocardiographic data, and pathologic analysis were recorded. End points for conduit failure were conduit replacement or dilation. A mean follow-up of 27 months (range, 2 to 46 months) was available for 47 survivors.

RESULTS

Procedure for conduit obstruction was required in 13 patients. The most common procedure was operation, and all but 3 patients had an unsuccessful balloon angioplasty before reoperation. Actuarial freedom from conduit dilation or reoperation was 93.6% (95% confidence limits, 82% to 99%), 81.9% (95% confidence limits, 64% to 91%), 77.8% (95% confidence limits, 39% to 78%), and 64.3% (95% confidence limits, 26% to 73%) at 1, 2, 3, and 4 postoperative years, respectively. Univariate analysis identified small conduit size as a risk factor for conduit obstruction.

CONCLUSIONS

Although this new conduit was not free from progressive obstruction, our clinical results (easy to work and good valvular function) and the availability in small sizes encouraged us to use it as an alternative to small-size homografts when those were not available.

Cardiomyoplasty: ventricular reconstruction after tumor resection

OBJECTIVE

Although cardiac transplantation has been performed for complete removal of ventricular tumors, complete surgical resection with ventricular reconstruction is desirable. Thus patients with benign tumors would probably be cured, and those with malignant tumors would have a better prognosis. In this study extensive and complete surgical resection of ventricular tumors is followed by anatomic and functional ventricular reconstruction with a dynamic cardiomyoplasty procedure.

METHODS

Seven patients (mean age, 32.7 years) underwent complete resection of ventricular tumors. Histologic types were distributed as follows: fibroma in 2 patients and sarcoma, lymphosarcoma, hemangioma, lipoma, and metastatic angiosarcoma, respectively, in the remaining 5 patients. Six of the patients were considered candidates for heart transplantation because of the extent of tumor invasion. Surgery consisted of 4 steps: (1) tumor resection; (2) coronary artery resection (when invaded by the tumor) and coronary artery bypass grafting; (3) valvular reconstruction (when possible) or replacement; and (4) ventricular wall reconstruction with a pericardial patch for closure of the ventricular defect (neoendocardium) covered by the electrostimulated latissimus dorsi muscle flap (neomyocardium).

RESULTS

All patients survived surgical intervention, but 2 late postoperative deaths are reported. Among the surviving patients, early complications played a major role in their postoperative course and consisted of arrhythmias, atrioventricular block necessitating a dual-chamber pulse generator, respiratory insufficiency, and heart failure. Two patients were assisted postoperatively with an intra-aortic balloon pump. On postoperative follow-up (mean, 72.4 +/- 8.5 months), an improvement in the patients' functional status was observed. Patients moved from a mean New York Heart Association functional class of 2.8 to a mean functional class of 1.2.

CONCLUSIONS

The excellent long-term evolution without recurrence, ventricular dysfunction, and/or thromboembolic complications implies that cardiomyoplasty could be recommended as an alternative to heart transplantation for the therapy of large ventricular tumors.

Thoracic calcifications in childhood

Thoracic calcifications are found in the following locations: mediastinum, lung, pleura, cardiovascular system, and thoracic wall. The calcifications of the mediastinum include mostly inflammatory lesions and malignant neoplasms. Pulmonary calcifications are mainly inflammatory lesions and metastases of osteosarcomas. Where the cardiovascular system is concerned, the most common calcifications are those of the heart relating to tumors or surgery. Calcifications of the aortic wall and valve calcifications can be found. In the thoracic wall there are calcifications of the bone and of soft tissues. The knowledge of shape and location is very useful for the diagnosis of the underlying disease. Calcifications in the thorax are frequently manifestations of previous infectious processes. Less often, they may be due to neoplasms, metabolic disorders, or previous medical therapy.

Coronary dilatation reserve in experimental hypertension and chronic heart failure: effects of blockade of the renin-angiotensin system

1. The aim of the present study was to investigate left and right ventricular (LV and RV, respectively) coronary vasodilatation reserve (CVR; fluorescent microsphere technique) in rats with hypertension (spontaneously hypertensive rats (SHR)) or congestive heart failure (CHF) and the effects of early and chronic renin-angiotensin system (RAS) blockade thereupon. 2. In adult SHR, both LV and RV CVR were impaired, especially in the non-hypertrophied RV, the main factor involved being coronary vascular remodelling. Blockade of the RAS normalized both LV and RV CVR, mainly through the prevention of hypertension and suppression of the resulting pericoronary fibrosis. 3. In postischaemic CHF rats, there was an early and severe degradation of LV and RV CVR that developed before any significant vascular remodelling and appeared to be linked to the deterioration of cardiac hypertrophy and haemodynamics. This degradation in CVR further worsened over the longer term due to late-developing pericoronary fibrosis and endothelial dysfunction. Blockade of the RAS had no early effects on LV and RV CVR, but improved RV CVR over the long term, mainly by limiting RV hypertrophy and by preventing the development of pericoronary fibrosis and coronary endothelial dysfunction. 4. In kallikrein-kinin system-deficient mice, CVR was not different from that of wild-type mice, suggesting that this system is not implicated in normal CVR regulation.

Age and gender effects on cardiomyocyte apoptosis in the normal human heart

BACKGROUND

Animal studies have suggested that apoptosis could play a significant role in the myocardial aging process. Although no information is available in humans, the paradigm that cardiomyocyte apoptosis is increased in the aged human heart has been widely propagated. Moreover, it is unknown whether gender differences may influence cardiomyocyte apoptosis.

METHODS

Cardiomyocyte apoptosis was compared between subjects ranging in age from 21 to 93 years (22 men and 19 women), free of any cardiovascular disease, who died of either violent or natural causes. Strict inclusion and exclusion criteria were used to ensure that the selected hearts accurately represented normal aging.

RESULTS

Apoptosis was detected using the TdT-mediated dUTP digoxigenin nick end labeling (TUNEL) technique (controls for TUNEL included negative staining for splicing factor SC-35 and for Ki-67 antigen). The percentage of cardiomyocyte death ranged from 0% to 0.0437%, with no correlation with the age of the subject (p =.85). However, the percentage of apoptosis was threefold higher in men than in women (0.0133% +/- 0.0030% vs 0.0042% +/- 0.0008%, respectively; p <.01).

CONCLUSIONS

Our results in humans do not support the hypothesis that aging influences the percentage of cardiomyocyte apoptosis. However, gender appears to be an important determinant of the occurrence of apoptosis.