Immunohistochemical comparison of vascular and sinusoidal adherens junctions in cavernosal endothelium.
OBJECTIVE
To characterize endothelial cell-to-cell junctions in the sinusoids and microvasculature of the corpus cavernosum.


METHODS
Corporal tissue was obtained from 6 potent human subjects, cut into 5-microm cryosections, and double-labeled with consecutive applications of primary and secondary antibodies. Laser scanning confocal microscopy identified subcellular localization of endothelial anchoring and adhesion molecules. Fluorescence intensity was rated as strong, weak, or absent by two observers.


RESULTS
The cavernosal endothelial adherens junction was composed of vascular endothelial cadherin, alpha-catenin, plakoglobin, vinculin, and the regulatory proteins beta-catenin and ZO-1. Adherens junctions in sinusoids were elongated, redundant, and narrow versus short, dense, linear cell-to-cell contacts in small arterioles and venules. Vinculin expression along the basal interface of the endothelium and stroma was weak in the sinusoids and strong in the arterioles. Definite sinusoidal expression of CD31 and CD34 was noted. P-selectin was only expressed within the cavernosal microvessels.


CONCLUSIONS
The regulatory and structural proteins extending from vascular endothelial cadherin provide immunohistochemical evidence of a role for adherens junctions in cavernosal endothelial barrier function and cellular homeostasis. The sinusoidal endothelium has a unique junctional phenotype consistent with its blood trapping function. Differential expression of functional proteins in sinusoidal and microvascular endothelium may reflect segmental variation in hemodynamic exposure to pressure, stretch, or flow.
Wessells
Hunter
H
Department of Urology, University of Washington School of Medicine and Harborview Medical Center, Seattle, Washington 98104, USA.
King
Stephen H
SH
Schmelz
Monika
M
Nagle
Raymond B
RB
Heimark
Ronald L
RL
D022005:Adherens Junctions / Q000737:chemistry / Q000648:ultrastructure*; D000328:Adult; D018952:Antigens, CD34 / Q000032:analysis; D001808:Blood Vessels / Q000737:chemistry / Q000166:cytology; D015820:Cadherins / Q000032:analysis; D003598:Cytoskeletal Proteins / Q000032:analysis; D051180:Desmoplakins; D042783:Endothelial Cells / Q000737:chemistry / Q000648:ultrastructure; D004730:Endothelium, Vascular / Q000737:chemistry / Q000166:cytology*; D006801:Humans; D008297:Male; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D008875:Middle Aged; D019007:P-Selectin / Q000032:analysis; D051419:Paxillin; D010413:Penis / Q000098:blood supply / Q000737:chemistry / Q000166:cytology*; D010750:Phosphoproteins / Q000032:analysis; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000032:analysis; D017154:Stromal Cells / Q000737:chemistry / Q000648:ultrastructure; D015534:Trans-Activators / Q000032:analysis; D014746:Vimentin / Q000032:analysis; D016596:Vinculin / Q000032:analysis; D051178:alpha Catenin; D051176:beta Catenin; D051185:gamma Catenin; D014841:von Willebrand Factor / Q000032:analysis
D018952:Antigens, CD34; C495273:CTNNA1 protein, human; C495270:CTNNB1 protein, human; D015820:Cadherins; D003598:Cytoskeletal Proteins; D051180:Desmoplakins; D019007:P-Selectin; C496061:PXN protein, human; D051419:Paxillin; D010750:Phosphoproteins; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D015534:Trans-Activators; D014746:Vimentin; D051178:alpha Catenin; D051176:beta Catenin; D051185:gamma Catenin; D014841:von Willebrand Factor; D016596:Vinculin