Evidence that human cardiac myocytes divide after myocardial infarction

BACKGROUND

The scarring of the heart that results from myocardial infarction has been interpreted as evidence that the heart is composed of myocytes that are unable to divide. However, recent observations have provided evidence of proliferation of myocytes in the adult heart. Therefore, we studied the extent of mitosis among myocytes after myocardial infarction in humans.

METHODS

Samples from the border of the infarct and from areas of the myocardium distant from the infarct were obtained from 13 patients who had died 4 to 12 days after infarction. Ten normal hearts were used as controls. Myocytes that had entered the cell cycle in preparation for cell division were measured by labeling of the nuclear antigen Ki-67, which is associated with cell division. The fraction of myocyte nuclei that were undergoing mitosis was determined, and the mitotic index (the ratio of the number of nuclei undergoing mitosis to the number not undergoing mitosis) was calculated. The presence of mitotic spindles, contractile rings, karyokinesis, and cytokinesis was also recorded.

RESULTS

In the infarcted hearts, Ki-67 expression was detected in 4 percent of myocyte nuclei in the regions adjacent to the infarcts and in 1 percent of those in regions distant from the infarcts. The reentry of myocytes into the cell cycle resulted in mitotic indexes of 0.08 percent and 0.03 percent, respectively, in the zones adjacent to and distant from the infarcts. Events characteristic of cell division--the formation of the mitotic spindles, the formation of contractile rings, karyokinesis, and cytokinesis--were identified; these features demonstrated that there was myocyte proliferation after myocardial infarction.

CONCLUSIONS

Our results challenge the dogma that the adult heart is a postmitotic organ and indicate that the regeneration of myocytes may be a critical component of the increase in muscle mass of the myocardium.

Spectrum of clinicopathologic manifestations of arrhythmogenic right ventricular cardiomyopathy/dysplasia: a multicenter study

OBJECTIVES

The aim of the present investigation was to redefine the clinicopathologic profile of arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC), with special reference to disease progression and left ventricular (LV) involvement.

BACKGROUND

Long-term follow-up data from clinical studies indicate that ARVC is a progressive heart muscle disease that with time may lead to more diffuse right ventricular (RV) involvement and LV abnormalities and culminate in heart failure.

METHODS

Forty-two patients (27 male, 15 female; 9 to 65 years old, mean [+/-SD] age 29.6 +/- 18) from six collaborative medical centers, with a pathologic diagnosis of ARVC at autopsy or heart transplantation, and with the whole heart available, were studied according to a specific clinicomorphologic protocol.

RESULTS

Thirty-four patients died suddenly (16 during effort); 4 underwent heart transplantation; 2 died as a result of advanced heart failure; and 2 died of other causes. Sudden death was the first sign of disease in 12 patients; the other 30 had palpitations, with syncope in 11, heart failure in 8 and stroke in 3. Twenty-seven patients experienced ventricular arrhythmias (ventricular tachycardia in 17), and 5 received a pacemaker. Ten patients had isolated RV involvement (group A); the remaining 32 (76%) also had fibrofatty LV involvement that was observed histologically only in 15 (group B) and histologically and macroscopically in 17 (group C). Patients in group C were significantly older than those in groups A and B (39 +/- 15 years vs. 20 +/- 8.8 and 25 +/- 9.7 years, respectively), had significantly longer clinical follow-up (9.3 +/- 7.3 years vs. 1.2 +/- 2.1 and 3.4 +/- 2.2 years, respectively) and developed heart failure significantly more often (47% vs. 0 and 0, respectively). Patients in groups B and C had warning symptoms (80% and 87%, respectively, vs. 30%) and clinical ventricular arrhythmias (73% and 82%, respectively, vs. 20%) significantly more often than patients in group A. Hearts from patients in group C weighed significantly more than those from patients in groups A and B (500 +/- 150 g vs. 328 +/- 40 and 380 +/- 95 g, respectively), whereas hearts from both group B and C patients had severe RV thinning (87% and 71%, respectively, vs. 20%) and inflammatory infiltrates (73% and 88%, respectively, vs. 30%) significantly more often than those from group A patients.

CONCLUSIONS

LV involvement was found in 76% of hearts with ARVC, was age dependent and was associated with clinical arrhythmic events, more severe cardiomegaly, inflammatory infiltrates and heart failure. ARVC can no longer be regarded as an isolated disease of the right ventricle.

Cardiac metastases

Tumours metastatic to the heart (cardiac metastases) are among the least known and highly debated issues in oncology, and few systematic studies are devoted to this topic. Although primary cardiac tumours are extremely uncommon (various postmortem studies report rates between 0.001% and 0.28%), secondary tumours are not, and at least in theory, the heart can be metastasised by any malignant neoplasm able to spread to distant sites. In general, cardiac metastases are considered to be rare; however, when sought for, the incidence seems to be not as low as expected, ranging from 2.3% and 18.3%. Although no malignant tumours are known that diffuse preferentially to the heart, some do involve the heart more often than others--for example, melanoma and mediastinal primary tumours. This paper attempts to review the pathophysiology of cardiac metastatic disease, epidemiology and clinical presentation of cardiac metastases, and pathological characterisation of the lesions.

Echocardiographic findings in myocarditis

This study analyzes morphologic and functional alterations detected by M-mode and 2-dimensional echocardiography in 41 patients with histologically proven myocarditis and different clinical presentations: congestive heart failure (63%), atrioventricular block (17%), chest pain (15%) and supraventricular arrhythmias (5%). Left ventricular dysfunction was common (69%), particularly in patients with congestive heart failure (88%), often without or with minor cavity dilatation. Patients with atrioventricular block or chest pain had usually preserved ventricular function. Right ventricular dysfunction was present in 23%. Additional findings included asynergic ventricular areas (64%), left ventricular "hypertrophy" sometimes reversible (20%), hyperrefractile myocardial areas (23%), ventricular thrombi (15%) and "restrictive" ventricular filling (7%). It is concluded that echocardiographic features of myocarditis are polymorphous and nonspecific. The echocardiographic pattern can simulate alternatively dilated, hypertrophic, restrictive or "right" ventricular cardiomyopathy, as well as coronary artery disease. In an appropriate clinical context, echocardiography can be helpful in the diagnosis of myocarditis and in the selection of patients for endomyocardial biopsy.

Electrocardiography of myocarditis revisited: clinical and prognostic significance of electrocardiographic changes

To clarify the clinical and prognostic value of the ECG, an ECG review was undertaken in 45 consecutive patients with a histologic diagnosis of active myocarditis (29 men and boys and 16 women and girls; age, 36.8 +/- 15 years; idiopathic myocarditis, 39 cases). In patients (21) with symptoms of recent onset (less than or equal to 1 month) AV block and repolarization abnormalities were the prevailing ECG features at the time of admission, and a pseudoinfarction pattern (Q waves plus ST-segment elevation) frequently heralded a rapidly fatal course ("fulminant myocarditis"). Left atrial enlargement and atrial fibrillation, left ventricular hypertrophy and LBBB, which prevailed in patients who had symptoms for longer periods, corresponded to the most severe degree of left ventricular dysfunction during the initial hemodynamic and echocardiographic evaluation. The overall mortality rate after 58 +/- 24 months from the time of diagnosis was 29%. Abnormal QRS complexes and LBBB were markers of poor survival, independently of initial indexes of left and right ventricular function, both of which indicate an increased propensity for sudden cardiac death.

Articular cartilage repair in rabbits by using suspensions of allogenic chondrocytes in alginate

The feasibility of allogenic implants of chondrocytes in alginate gels was tested for the reconstruction in vivo of artificially full-thickness-damaged articular rabbit cartilage. The suspensions of chondrocytes in alginate were gelled by the addition of calcium chloride solution directly into the defects giving in situ a construct perfectly inserted and adherent to the subchondral bone and to the walls of intact cartilage. The tissue repair was controlled at 1, 2, 4 and 6 months after the implant by NMR microscopy, synchrotron radiation induced X-ray emission to map the sulfur of glycosaminoglycans and by histochemistry. Practically a complete repair of the defect was observed 4-6 months from the implant of the chondrocytes with the recovery of a normal tissue structure. Controls in which Ca-alginate alone was implanted developed only a fibrous cartilage.

Left ventricular involvement in right ventricular dysplasia

Right ventricular dysplasia, a heart muscle disease of unknown cause, anatomically characterized by variable replacement of myocardial muscle with adipose or fibroadipose tissue, is usually considered a selective disorder of the right ventricle. However, concomitant left ventricular involvement has been noted in a few cases. The aim of this study was to evaluate the prevalence and characteristics of left ventricular involvement in right ventricular dysplasia, as well as possible progression of the disease. Thirty-nine patients with right ventricular dysplasia were studied by M-mode and two-dimensional echocardiography; 28 of them also underwent cardiac catheterization, and in 25 endomyocardial biopsy was performed. On first examination the left ventricle was normal in 25 patients, whereas in the remaining 14 right ventricular abnormalities were associated with left ventricular involvement, characterized by asynergic areas (12 patients) or diffuse mild hypokinesis (two patients). During follow-up (27 patients, 84.1 +/- 66.1 months) 10 patients showed worsening of right ventricular function; in nine the appearance or worsening of left ventricular abnormalities was observed. Five patients died (four in congestive heart failure and one suddenly). Results of postmortem examination (available in two patients) showed atrophy of myocells and a massive fatty and fibrous infiltration of the right ventricular wall, associated with degenerative changes and fibrosis of the left ventricle. In conclusion, right ventricular dysplasia may be associated with left ventricular involvement and the disorder appears to be progressive in some instances.

Magnetic resonance imaging in right ventricular dysplasia

Fifteen patients with right ventricular dysplasia were investigated by T1-weighted spin- and gradient-echo pulse sequences, using a protocol that enabled both a subjective analysis of myocardial signal intensity and a quantitative/qualitative analysis of right and left ventricular function. In 8 patients, 3 investigators independently recognized abnormally hyperintense areas in the anatomic sites usually affected by the disease. In 7 of these patients, these areas showed an overlap with a-dyskinetic areas imaged by both magnetic resonance imaging (MRI) and echocardiography. In 1 patient who underwent a cardiac transplant, MRI of the explanted heart showed an excellent correlation between the distribution of the lesions and the in vivo/in vitro features. The data were compared with those from an equivalent sample of patients affected by dilated cardiomyopathy. In the latter patients, no focal hyperintensities were attributed to any anatomic sites in the right ventricule, and no focal a-dyskinetic foci were observed. Furthermore, the 2 groups of patients were significantly different in regard to dimensional and functional quantitative parameters. The results suggest that MRI is useful in integrating echocardiographic data and can be helpful in diagnosing this disease in late stages.

Laparoscopic management of acute small-bowel obstruction

BACKGROUND

A retrospective review is given of the authors' experience with a consecutive series of acute small-bowel obstruction unresponsive to medical management.

METHODS

There were 33 exploratory laparoscopies. The etiology was accurately diagnosed in 100% of the cases. Twenty-five (76%) were secondary to postoperative adhesions, of which 18 (72%) were successfully treated by laparoscopic lysis of adhesions. Minilaparotomy was needed to treat iatrogenic perforation (two), gangrenous bowel (one), and Meckel's diverticulectomy (one). Formal laparotomy was utilized for small-bowel resection (two), malignant adhesions (two), and intolerance of pneumoperitoneum (one). Four cases of incarcerated hernias were treated by conventional herniorrhaphy.

RESULTS

Overall, 67% of our cases were spared formal laparotomy.

CONCLUSION

We conclude that laparoscopy is an excellent diagnostic modality in acute small-bowel obstruction, the majority of which can be simultaneously managed laparoscopically. Laparotomy should be reserved for malignant adhesions, surgical misadventure, or when the pathology dictates.

Morphological findings in apparently idiopathic ventricular tachycardia. An echocardiographic haemodynamic and histologic study

In order to investigate the anatomic substrate of 'idiopathic' ventricular tachycardia (VT) 10 patients with chronic recurrent VT and no apparent sign of heart disease underwent an echocardiographic, haemodynamic and histologic study (5 males, 5 females: mean age = 40 +/- 11 years). In the patients with a left bundle branch block morphology of VT (7 cases), four showed findings compatible with an arrhythmogenic right ventricular dysplasia or a right ventricular cardiomyopathy. In the other three all examinations were normal with the exception of endomyocardial biopsy, which showed slight non specific changes in two. Of the remaining 3 cases (characterized by a right bundle branch block morphology of VT or by the presence of polymorphic VT) one had histologic evidence of myocarditis while another developed dilated cardiomyopathy. Macroscopic and/or microscopic ventricular abnormalities are frequently found in patients with VT which appears idiopathic. In these cases myocardial disease is frequently progressive, despite optimal control of VT.

Epidemiology of dilated cardiomyopathy. A prospective post-mortem study of 5252 necropsies. The Heart Muscle Disease Study Group

Dilated cardiomyopathy is a heart muscle disease of unknown aetiology, characterized by left ventricular dilatation and impaired systolic function. Data on the incidence and prevalence of the disease is ambiguous, due to geographic variations, patient selection and the diagnostic criteria adopted.

METHODS

All the post-mortem and clinical cases observed in a consecutive series of 5252 patients resident in Trieste during the period November 1987-November 1989 were studied.

RESULTS

Incidence of the disease discovered at autopsy was estimated at 4.5/100,000/year (24 cases), while clinical incidence in the same period was 2.45/100,000/year (13 cases). This is a total incidence of 6.95/100,000 new cases a year. A possible family history of heart muscle disease was found in three patients (12.5%). In 15 patients (62.5%) deaths were due to cardiological complications. Endocardial thickening (P = 0.03), fatty infiltration (P = 0.01) and arterial involvement (P = 0.04) were found more frequently in older patients (> 65 years).

CONCLUSIONS

The study confirms that dilated cardiomyopathy in Europe has a higher incidence than previously suggested and emphasizes the need for greater diagnostic sensitivity, particularly since pharmacological treatment is now so effective.

Clinical and pathologic study of familial dilated cardiomyopathy

To evaluate the occurrence of familial cases of dilated cardiomyopathy (DC), 165 consecutive patients were studied. Diagnosis of myocardial disease was based on clinical, hemodynamic, bioptic, postmortem or a combination of these criteria. Twelve patients (7% of cases) showed evidence of myocardial disease in greater than or equal to 1 relative; 27 patients with myocardial disease were detected in the 12 families, but a suspected history of myocardial involvement was present in a further 16 cases. In 6 families proband and relatives were affected by DC (total 14 cases); in 1 of these families the disease began with an atrioventricular block. In 4 families the relatives showed the presence of myocarditis at the endomyocardial biopsy. In 2 families the relatives presented a right ventricular cardiomyopathy. The mode of inheritance was autosomal dominant in 7 families, recessive in 4; X-linked pattern may be hypothesized in 1. Nine patients died under the age of 45 years: 2 of sudden death, 6 of chronic heart failure and 1 of cerebral embolism. Familial transmission is not rare. Different modes of genetic transmission (autosomal dominant, recessive and X-linked) and different forms of myocardial disease suggest that familial DC may be a multifactorial disease.

Right precordial ST and QRS changes in the diagnosis of right ventricular infarction

Two groups of patients with anatomically proved acute myocardial infarction were compared in order to study specificity and sensitivity of the ECG criteria previously described in clinical and experimental right ventricular infarction ( RVI ). Group 1 included 21 patients with left inferior infarction and with a variable degree of right ventricular involvement; group 2 included nine patients with myocardial infarction confined to the left inferior wall. In both groups the presence of ST elevation (at least 0.05 mV) and the morphology of the QRS complex in V4R , V3R, and V1 were assessed in ECGs performed at the time of admission. Also, in order to evaluate the morphology of the ST segment and QRS complex in right precordial leads in normal subjects, an ECG with 12 standard and four right precordial leads ( V6R to V3R) was performed in 82 subjects (group 3) without clinical and ECG evidence of heart disease. Our data reveal that in normal subjects an rS pattern is always present in V3R and frequently (91%) in V4R . On the contrary, the presence of QS or QR complexes in both V4R and V3R are specific markers of right ventricular necrosis (specificity 100%; sensitivity 78%). The presence of injury and necrosis waves in V4R or V4R to V3R during inferior infarction is a useful diagnostic criterion in that it insures a highly specific diagnosis of acute RVI in the great majority (76 and 71%, respectively) of the cases with autopsy evidence of right ventricular involvement.

Lamivudine allows completion of chemotherapy in lymphoma patients with hepatitis B reactivation

Reactivation of hepatitis B virus in patients receiving chemotherapy for non-Hodgkin's lymphoma (NHL) may give rise to hepatitis, hepatic failure and death, and prevent further chemotherapy. We report four patients with NHL in whom hepatitis flare-up was observed after two (three patients) and six (one patient) cycles of chemotherapy. After spontaneous recovery, they were treated with Lamivudine (100 mg/day), which enabled completion of chemotherapy without further hepatitis B reactivation. In one patient, high-dose chemotherapy and autologous stem cell transplantation was also performed. These data suggest a possible role for Lamivudine in preventing hepatitis B reactivation during chemotherapy administration to chronic carriers of the hepatitis B virus. Moreover, it enabled the completion of both standard and high-dose chemotherapy in patients with previous hepatitis B reactivation.

Wound closure technique and acute wound complications in gastric surgery for morbid obesity: a prospective randomized trial

BACKGROUND

During the past 10 years, numerous clinical studies have supported the use of continuous monofilament fascial closure after laparotomy. Because of the increased incidence of surgical-site infections and other acute wound complications in the morbidly obese, these patients are well suited for a study of technical factors that may affect the frequency of these wound complications.

STUDY DESIGN

A prospective, randomized study of the midline fascial closure technique in gastric bariatric operations was conducted between 1991 and 1998 in 331 consecutive morbidly obese patients. At the time of closure of the upper midline laparotomy wound, the patients were randomized into two groups: Group I patients (n = 172) underwent continuous fascial closure and group II patients (n = 159) underwent interrupted fascial closure. All patients received prophylactic antibiotics in a similar fashion. Wounds were monitored for 30 days postoperatively, and acute wound complications were classified as superficial or deep. Superficial complications included superficial surgical-site infections, seromas, and hematomas. In all superficial complications, the fascia remained uninvolved and intact. Deep wound complications included deep surgical-site infections and fascial dehiscence.

RESULTS

A total of 49 acute wound complications occurred (15%). There were 22 superficial (7%) and 27 deep (8%) wound complications in the 331 in the patients studied. Group I patients experienced fewer total wound complications than group II patients (18 versus 31; p=0.021). Group I patients also experienced fewer deep wound complications than group II (5 versus 22; p = 0.003).

CONCLUSIONS

Continuous fascial closure reduces major acute wound complications in morbidly obese patients undergoing gastric operations for obesity.

Cyclo-oxygenase-2 (COX-2) expression at the site of recent myocardial infarction: friend or foe?

BACKGROUND

Cyclo-oxygenase-2 (COX-2) is induced in cardiomyocytes only in response to stress, such as ischaemia.

OBJECTIVE

To assess COX-2 expression at the site of recent myocardial infarction.

METHODS

COX-2 expression was evaluated by specific immunostaining in cardiomyocytes from 23 subjects who died 10-60 days after acute myocardial infarction. The relation between COX-2 myocardial expression and apoptotic rate was investigated. Cardiomyocyte apoptotic rate was defined as the number of cells co-expressing in situ end labelling of DNA fragmentation (TUNEL) and immunostaining for activated caspase-3.

RESULTS

COX-2 expression was found in cardiomyocytes at the site of infarction in nine of 23 cases (39%). It was associated with fivefold higher apoptotic rates (median 17.9% (interquartile range 11.0-25.4%) v 3.7% (0.6-12.8%); p = 0.016), and apoptotic rate increased progressively from mild to intense COX-2 staining (p for trend 0.009). COX-2 expression co-localised with TUNEL nuclear staining in myocytes, and there was a high concordance between COX-2 and hypoxia induced factor 1-alpha staining (78%, p = 0.021) and between COX-2 and bax (83%, p = 0.014). Subjects showing myocardial COX-2 expression were more likely to have enlarged hearts (p = 0.050), and intense COX-2 staining was strictly associated with symptomatic heart failure (p = 0.035).

CONCLUSIONS

COX-2 is expressed in cardiomyocytes in nearly 40% of cases at the site of recent acute myocardial infarction, even late after the index event. Its expression was associated with extremely high apoptotic rates. These findings suggest a potential cause-effect link between COX-2 expression and enhanced myocardial apoptosis in ischaemic cardiomyopathy.

The genotype of the hepatitis C virus in patients with HCV-related B cell non-Hodgkin's lymphoma

Increasing evidence suggests that the hepatitis C virus (HCV) might be involved in the pathogenesis of B cell non-Hodgkin's lymphomas (NHL). Since several HCV genotypes are currently identifiable and might be involved in the pathogenesis of different diseases (with different severity and responsiveness to therapy), the aim of our study was to assess the prevalence of viral genotypes in a group of patients with HCV-related NHL. Among 470 consecutive patients, 42 HCV Ab-positive cases were identified. HCV RNA could be detected by reverse transcriptase-polymerase chain reaction and genotyping performed in 31 of these cases. As compared to our control group (211 healthy blood donors and patients with chronic liver disease), a striking high prevalence of genotype 2ac was detected among B cell NHL (48.4 vs 9.0%), with a relative risk of infection of 5.37 (P < 0.0001). No major differences were observed in the distribution of NHL histotypes and in the clinical features among patients with genotype 1b (the other most frequent genotype) or 2ac, a part from a trend towards a higher percentage of liver disease and a lower likelihood of response to interferon for patients with genotype 1b. The same high prevalence of genotype 2ac has been recently reported in patients with mixed cryoglobulinemia (MC), monoclonal gammopathies, B cell NHL complicating MC and autoimmune hepatitis. All these data taken together suggest that genotype 2ac might be involved in the pathogenesis of lymphoproliferative and autoimmune disorders.

Meningeal and cerebral involvement in multiple myeloma patients

Cerebral involvement is an unusual complication in multiple myeloma: herein four patients who presented myelomatous meningitis with multiple intraparenchymal lesions or a localized cerebral plasmacytoma are described. Two of these patients relapsed with meningeal involvement and a very limited disease outside the central nervous system after an initial complete remission obtained with induction chemotherapy. In the other two cases, the cerebral tumor appeared during first-line treatment. Cytological examination of the cerebrospinal fluid and magnetic resonance were essential for diagnosis. Different modalities of treatment were used, including intrathecal chemotherapy, cranial irradiation, and systemic chemotherapy with high-dose methotrexate and cytarabine, achieving improvement of neurological symptoms in three of four patients.

Incidence and diagnosis of EDTA-dependent pseudothrombocytopenia in a consecutive outpatient population referred for isolated thrombocytopenia

Among 111 patients referred to our outpatient clinic for isolated thrombocytopenia during a 24-month period, 17 (15.3%) cases of EDTA-dependent pseudothrombocytopenia (EDTA-PTCP) were identified. EDTA-PTCP represented the second most frequent cause of thrombocytopenia in this population. The diagnosis was confirmed by the following findings: (a) normal platelet numbers immediately after blood withdrawal; (b) progressive fall of platelet counts and evident platelet clumping over time, only in EDTA-anticoagulated blood. A simple, inexpensive and quick diagnostic method was devised, that consists in evaluating the platelet number in a blood sample anticoagulated with EDTA immediately after blood withdrawal and 4 h later.

Surviving acute myocardial infarction: survivin expression in viable cardiomyocytes after infarction

BACKGROUND

Apoptosis is a key feature in postinfarction remodelling leading to progressive myocyte loss. Both proapoptotic and antiapoptotic factors contribute to the delicate balance between death and survival. The survivin pathway has emerged as essential in the control of apoptosis, although its role in heart disease is unknown.

AIM

To evaluate survivin expression after acute myocardial infarction (AMI).

METHODS

Survivin expression was assessed immunohistochemically in the peri-infarct and remote viable myocardium in 17 consecutive patients who died 1-30 weeks after AMI and in four control hearts.

RESULTS

Survivin was expressed by myocytes in the peri-infarct area in eight patients and in the remote region in 13 patients. The rate of survivin expression after AMI was significantly higher in the remote versus peri-infarct regions and compared with control hearts. Its expression was inversely associated with the presence of dilated cardiopathy and of apoptosis, independently from the gross pathology infarct size.

CONCLUSIONS

Survivin myocardial expression after AMI may be associated with the survival of at risk myocardium and may be indicative of more favourable remodelling after AMI. These findings identify a potential new target for the treatment of postinfarction remodelling.