Clusters of proliferating endothelial cells and smooth muscle cells in rabbit carotid arteries.
Schwarz and Benditt found clustering of replicating cells in aortic endothelium in 1976 and discussed how homeostasis of the arterial wall is maintained through this nonrandom distribution of replicating cells. However, it is still unclear how cells of vascular walls turnover. In order to address this issue, we evaluated distribution of the cells in mitotic cycle, labeled by Ki67-immunostaining, in serial histological sections of twelve carotid arteries of six adult male Japanese rabbits. As a result, a total of 1713 Ki67-positive endothelial cells (ECs) and 1247 Ki67-positive smooth muscle cells (SMCs) were identified. The Ki67-positivity rate in ECs and SMCs were about 0.048% and 0.0027%, respectively. Many of the Ki67-positive cells clustered in two (EC, 37%; SMC, 33%), three to four (EC, 8%; SMC, 28%), and five to eight cells (EC, 5%; SMC, 10%). Clusters having more than eight cells were not found. Thus, it can be speculated that the cell division of proliferating ECs and SMCs occur four times at most. These novel findings offer great insights for better understanding of the mechanism that underlies cell number regulation of the blood vessel.
Diagnostic Pathology, Akita Kosei Medical Center, Akita City, Japan.
Masato
M
Takahashi
Department of Clinical Laboratory, Ogachi Central General Hospital, Yuzawa City, Japan.
Hirotake
H
Masuda
Department of Cellular and Organ Pathology, Graduate School of Medicine, Akita University, Akita City, Japan.
Makoto
M
Yoshida
Department of Cellular and Organ Pathology, Graduate School of Medicine, Akita University, Akita City, Japan.
Yukinobu
Y
Ito
Department of Surgical Pathology, Akita University Hospital, Akita City, Japan.
Hiroshi
H
Nanjo
Diagnostic Pathology, Akita Karyology and Histology Research Center, Yurihonjo City, Akita, Japan.
Tatsuo
T
Sugiyama
Department of Cellular and Organ Pathology, Graduate School of Medicine, Akita University, Akita City, Japan.
Daichi
D
Maeda
Department of Cellular and Organ Pathology, Graduate School of Medicine, Akita University, Akita City, Japan.
Akiteru
A
Goto
D000818:Animals; D002339:Carotid Arteries / Q000166:cytology*; D002455:Cell Division / Q000502:physiology; D049109:Cell Proliferation / Q000502:physiology*; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000166:cytology*; D004730:Endothelium, Vascular / Q000166:cytology; D009131:Muscle, Smooth, Vascular / Q000166:cytology*; D032389:Myocytes, Smooth Muscle / Q000166:cytology*; D011817:Rabbits
Ki67; carotid artery; endothelial cells; rabbit; serial section; smooth muscle cells