Immunohistochemical detection of myocardial necrosis in stillbirth and neonatal death

Confirmation of Heart Malformations in Fetuses in the First Trimester Using Three-Dimensional Histologic Autopsy

BACKGROUND

We aimed to evaluate the usefulness of three-dimensional (3D) reconstruction of histology slides to confirm congenital heart disease (CHD) detected by first-trimester fetal cardiac ultrasonography. Conventional autopsy is hindered by the small size of the first-trimester fetal heart, and current CHD confirmation studies employ the use of highly specialized and expensive methods.

TECHNIQUE

An extended first-trimester ultrasound examination protocol was used to diagnose fetal heart anomalies. Medical termination of pregnancies was followed by fetal heart extraction. The specimens were sliced, and the histology slides were stained and scanned. The resulting images were processed, and volume rendering was performed using 3D reconstruction software. The volumes were analyzed by a multidisciplinary team of maternal-fetal medicine subspecialists and pathologists and compared with ultrasound examination findings.

EXPERIENCE

Six fetuses with heart malformations were evaluated using histologic 3D imaging: two with hypoplastic left heart syndrome, two with atrioventricular septal defects, one with an isolated ventricular septal defect, and one with transposition of the great arteries. The technique allowed us to confirm ultrasound-detected anomalies and also identified additional malformations.

CONCLUSION

After pregnancy termination or loss, histologic 3D imaging can be used to confirm the presence of fetal cardiac malformations detected during first-trimester ultrasound examination. Additionally, this technique has the potential to refine the diagnosis for counseling regarding recurrence risk and retains the advantages of standard histology.

Diagnosis and intervention of severe tricuspid regurgitation secondary to rupture of the chordae tendineae: A case report and literature review

Unguarded severe tricuspid regurgitation caused by rupture of papillary muscle or chordae tendineae is rare but fatal in neonates. The experience in the management of these patients is still limited. A newborn presenting severe cyanosis after delivery was diagnosed with severe tricuspid regurgitation secondary to rupture of chordae tendineae by echocardiography (Echo), then treated by surgical reconstruction of chordae/papillary muscle connection without artificial materials. A takeaway lesson from this case is that Echo is an important method to diagnose a rupture of chordae tendineae or papillary muscle and that prompt diagnosis and timely surgery can be life-saving.

Cardiac ion channels associated with unexplained stillbirth - an immunohistochemical study

OBJECTIVES

Despite the use of post-mortem investigations, approximately 20% of stillbirths remain unexplained. Cardiac ion channelopathies have been identified as a cause of death in Sudden Infant Death Syndrome (SIDS) and could be associated with unexplained stillbirths. This study aimed to understand if the expression or localisation of cardiac ion channels associated with channelopathies were altered in cases of unexplained stillbirths.

METHODS

A case control study was conducted using formalin-fixed cardiac tissue from 20 cases of unexplained stillbirth and a control group of 20 cases of stillbirths from intrapartum hypoxia. 4 µm tissue sections were stained using haematoxylin and eosin, Masson's trichrome (MT) and Elastic van Gieson (EVG). Immunohistochemistry (IHC) was performed using antibodies against CACNA1G, KCNJ2, KCNQ1, KCNH2 and KCNE1. The cardiac conduction system in samples stained with MT and EVG could not be identified. Therefore, the levels of immunoperoxidase staining were quantified using QuPath software.

RESULTS

The nuclear-cytoplasmic ratio of sections stained with haematoxylin and eosin was higher for the hypoxia group (hypoxia median 0.13 vs. 0.04 unexplained, p < 0.001). CACNA1G (unexplained median 0.26 vs. hypoxia 0.30, p=0.009) and KCNJ2 (unexplained median 0.35 vs. hypoxia 0.41, p=0.001) had lower staining intensity in the unexplained stillbirth group. There were no statistically significant differences in the staining intensity of KCNQ1, KCNH2 and KCNE1.

CONCLUSIONS

Two ion channels associated with channelopathies demonstrated lower levels of expression in cases of unexplained stillbirth. Further genetic studies using human tissue should be performed to understand the association between channelopathies and otherwise unexplained stillbirths.

Field investigation of perinatal mortality in friesian cattle associated with myocardial degeneration and necrosis

Perinatal mortality and stillbirths were investigated in an extensively managed herd of Friesian cows and heifers calving over a 2-year period: 504 cows were calved and 215 heifers. Cows were bred to Friesian and Jersey bulls using natural service. The perinatal fetal mortality rate was 7.5% for cows and 30% for heifers. An experienced stockman managed these calvings and veterinary assistance was required only on nine occasions. All stillborn fetuses were examined post-mortem by the Veterinary Laboratories Agency, Carmarthen and no infectious agent was identified on any occasion. Thyroid hyperplasia was found in two fetuses. In blood samples taken from 10 late pregnant heifers, mean glutathione peroxidase values were 7.9 +/- 1.7 IU/ml Packed Cell Volume (PCV). Tissues from eight fetuses were submitted to the University of Liverpool for histopathological examination; all presented lesions consistent with myocardial degeneration and necrosis of the left ventricle. Following treatment of 205 late pregnant heifers with sodium selenite and vitamin E, the overall perinatal mortality rate in these cattle fell to below 11%.

Neonatal mitral and tricuspid valve repair for in utero papillary muscle rupture

BACKGROUND

Papillary muscle rupture in the fetus and neonate is a rare event that leads to severe mitral or tricuspid insufficiency and is associated with high perinatal mortality. We undertook surgical repair of this lesion in the neonatal period and report on our midterm results.

METHODS

Three neonates with tricuspid insufficiency and 1 infant with mitral insufficiency, all due to papillary muscle or chordal rupture, underwent surgical repair with artificial chordal replacement and a modification of the de Vega annuloplasty technique that allowed external adjustment of the annulus size under transesophageal echocardiographic guidance after separation from cardiopulmonary bypass.

RESULTS

All patients recovered well from the operation. There have been no late deaths and no valve-related complications. On discharge, all 3 patients had evidence of trace to mild atrioventricular valve regurgitation. At a median follow-up of 33 months (range, 7 to 50; 123 patient-months), all 4 patients are growing normally. Three patients have had no change in the degree of tricuspid or mitral regurgitation. One patient required reoperation at 54 months postoperatively for acute mitral insufficiency secondary to separation of an artificial chorda from the ventricular wall.

CONCLUSIONS

Surgical repair of critical neonatal tricuspid and mitral insufficiency associated with papillary muscle or chordal rupture is feasible and can result in good early and midterm results. Our modification of the De Vega annuloplasty technique with the ability to externally adjust the size of the annulus under echocardiographic guidance may improve the accuracy of the repair in the neonate.

Diagnostic utility of tenascin-C for evaluation of the activity of human acute myocarditis

Tenascin-C (TN-C) is an extracellular matrix protein that is expressed transiently in close association with tissue remodelling in various body sites. In the heart, TN-C is only present during early stages of development, is not expressed in the normal adult, but reappears in pathological states. The purpose of this study was to analyse the expression of TN-C in myocardial tissue from myocarditis patients, and to evaluate the diagnostic value of immunostaining for TN-C in the assessment of inflammatory activity in biopsy specimens. A total of 113 biopsy specimens obtained from 32 patients with a clinical diagnosis of acute myocarditis were examined by immunohistochemistry and in situ hybridization for TN-C. The immunostaining was semi-quantified and compared with histological diagnosis according to the Dallas criteria. Furthermore, serial biopsies from 22 patients were taken during convalescence, and sequential changes in TN-C levels were analysed. Expression of TN-C was specifically detected in endomyocardial biopsy specimens from patients with active-stage inflammation, and disappeared in healed stages. The degree of expression of TN-C correlated with the severity of histological lesions. These data suggest that TN-C reflects disease activity in cases of human myocarditis. Immunostaining for TN-C could enhance the sensitivity and accuracy of diagnosis using biopsy specimens.

Intrauterine left chamber myocardial infarction of the heart and hydrops fetalis in the recipient fetus due to twin-to-twin transfusion syndrome

A rare complication of twin-to-twin transfusion syndrome (TTTS) is described: myocardial infarction of the recipient fetus. Myocardial infarction and hydrops are considered to be consequences of hypertension in the recipient. No other organs were affected. Pathological signs of intrauterine hypertension were estimated by the thickness of vessel walls and signs of hypertrophied myocardial cells. In the heart of the recipient fetus there was a chronic myocardial infarction near the apex cordis on the anterior wall with an aneurysm 4x5 mm in diameter. Diagnosis was based on light microscopic examination. The poor myocardial systolic function resulted in hydrops. Since the mother was administered beta sympathomimetics in therapeutic doses the contribution of the drug to the myocardial infarction is uncertain, but we would like to suggest this as a possible adverse effect in TTTS. The present case is the first reported myocardial infarction in connection with the syndrome.