Razon M J, Kräling B M, Mulliken J B, Bischoff J
Surgical Research Laboratory, Children's Hospital, Boston, MA 02115, USA.
Microcirculation. 1998;5(2-3):189-95.
Hemangioma is an endothelial cell tumor that grows rapidly during infancy and regresses slowly during childhood. However, little is known about the natural history of this common tumor. To gain insight into the cellular mechanisms that underlie the switch from uncontrolled growth to involution of endothelium, we investigated the extent of cellular apoptosis versus proliferation in hemangioma specimens that spanned the natural life cycle of the tumor.
We analyzed apoptosis and cellular proliferation in frozen sections from 16 hemangioma specimens using the TUNEL assay to detect apoptotic cells and the Ki67 antigen to detect dividing cells.
Apoptosis was low in proliferative phase hemangiomas but increased fivefold in involutive phase specimens obtained from children one to four years of age. Immunofluorescence double-labeling experiments showed that at least one third of the apoptotic cells were endothelial. As expected, cellular proliferation was high in specimens up to 2 years of age but decreased significantly thereafter. Apoptosis was consistently low in nine normal skin tissues (newborn to 4 years of age) obtained from discarded pathology specimens.
These results suggest that increased apoptosis during the second year of life can offset cellular proliferation and may be involved in initiating regression of hemangioma.
血管瘤是一种内皮细胞瘤，在婴儿期生长迅速，在儿童期缓慢消退。然而，对于这种常见肿瘤的自然病程知之甚少。为了深入了解内皮细胞从不受控制的生长转变为退化的细胞机制，我们研究了跨越肿瘤自然生命周期的血管瘤标本中细胞凋亡与增殖的程度。
我们使用TUNEL法检测凋亡细胞，用Ki67抗原检测分裂细胞，分析了16例血管瘤标本冰冻切片中的凋亡和细胞增殖情况。
增殖期血管瘤的凋亡率较低，但在1至4岁儿童的消退期标本中凋亡率增加了五倍。免疫荧光双标记实验表明，至少三分之一的凋亡细胞是内皮细胞。正如预期的那样，2岁以下标本中的细胞增殖率较高，但此后显著下降。从废弃病理标本中获取的9例正常皮肤组织（新生儿至4岁）中的凋亡率一直较低。
这些结果表明，生命第二年凋亡增加可抵消细胞增殖，并可能参与启动血管瘤的消退。
