Abnormally extended ductal tissue into the aorta is indicated by similar histopathology and shared apoptosis in patients with coarctation.
BACKGROUND
The pathogenesis of coarctation of the aorta (CoA) has not been clearly elucidated. It is hypothesized that CoA patients have abnormal extension of ductal tissue into the aorta which plays some pathogenic role. The aim of this study was to investigate the extension of ductal tissue into the aorta in CoA patients by comparative analysis of ductal and aortic tissue histopathology, smooth muscle cell (SMC) phenotypes and apoptosis.


METHODS
Fifteen cases of surgically resected specimens including coarctation segment (CS), ductus arteriosus (DA) and transition zone (TZ) were histologically reviewed. SMC phenotypes were determined by immunohistochemistry for myosin heavy chain isoforms SM1, SM2, SMemb and α-smooth muscle actin. Apoptotic cell death was estimated by the TUNEL method.


RESULTS
A considerable amount of ductal tissue was found in CS and TZ in all investigated cases. CS showed a histologic pattern similar to that of closing DA. CS showed the least differentiated SMC phenotype and TZ intima displayed SMC phenotype more similar to that of DA than that of the normal aorta. TUNEL-positive cell deaths were frequently found in the media of both CS and DA, but absent in TZ.


CONCLUSIONS
Abnormal extension of ductal tissue into the aorta in CoA patients was indicated by similar histology and shared apoptosis. SMC phenotypic modulation may be involved in the formation of CoA. Our results strongly support the hypothesis that abnormal extension of ductal tissue in the aorta plays a crucial role in the pathogenesis of CoA.
Kim
Ji Eun
JE
Department of Pathology, Seoul National University Boramae Hospital, Republic of Korea.
Kim
Ee-Kyung
EK
Department of Pediatrics, Seoul National University Children's Hospital, 103 Daehangno, Jongno-gu Seoul, 110-799, Republic of Korea. Electronic address: kimek@snu.ac.kr.
Kim
Woong-Han
WH
Department of Thoracic and Cardiovascular Surgery, Seoul National University Children's Hospital, Republic of Korea.
Shim
Gyu Hong
GH
Department of Pediatrics, College of Medicine, Inje University, Sanggye Paik Hospital, Republic of Korea.
Kim
Han-Suk
HS
Department of Pediatrics, Seoul National University Children's Hospital, 103 Daehangno, Jongno-gu Seoul, 110-799, Republic of Korea.
Park
June Dong
JD
Department of Pediatrics, Seoul National University Children's Hospital, 103 Daehangno, Jongno-gu Seoul, 110-799, Republic of Korea.
Bae
Eun Jung
EJ
Department of Pediatrics, Seoul National University Children's Hospital, 103 Daehangno, Jongno-gu Seoul, 110-799, Republic of Korea.
Kim
Beyong Il
BI
Department of Pediatrics, Seoul National University Bundang Hospital, Republic of Korea.
Noh
Chung Il
CI
Department of Pediatrics, Seoul National University Children's Hospital, 103 Daehangno, Jongno-gu Seoul, 110-799, Republic of Korea.
Choi
Jung-Hwan
JH
Department of Pediatrics, Seoul National University Children's Hospital, 103 Daehangno, Jongno-gu Seoul, 110-799, Republic of Korea.
D001011:Aorta / Q000002:abnormalities* / Q000473:pathology* / Q000601:surgery; D001017:Aortic Coarctation / Q000473:pathology* / Q000601:surgery; D017209:Apoptosis / Q000502:physiology; D004373:Ductus Arteriosus / Q000002:abnormalities* / Q000473:pathology* / Q000601:surgery; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male