Acta Neuropathologica
Acta Neuropathol. (Berl.) 45, 159- 160 (1979)
Springer-Verlag 1979
Tight Junctions in Choroid Plexus Papillomas S. Wakai, M. Matsutani, H. Mizutani, and K. Sano Department of Neurosurgery, Faculty of Medicine, University of Tokyo, Hongo, Tokyo, 113 Japan
Summary. F o u r cases o f choroid plexus papilloma (CPP) obtained at the time o f surgical excision were examined by electron microscopy and c o m p a r e d with normal choroid plexus (CP) of mouse and chick. In apical tight junctions fusion o f the two outer leaflets o f the adjacent cytoplasmic m e m b r a n e was verified as in CP. This fact suggests that there is a b l o o d - C S F barrier not only in CP but also in CPP.
3 h (Luff, 1971), and then, or after immersion in 1% uranyl acetate for 2 h at room temperature, they were dehydrated in graded series of ethanols and embedded in Araldite or Epon. Histologic sections were prepared by standard laboratory procedures. Ultrathin sections were cut with an LKB ultramicrotome, stained both with uranyl acetate and lead citrate and examined in an Hitachi HU-I1DS electron microscope.
Results and Discussion Key words: Tight j u n c t i o n -- C h o r o i d plexus papill o m a - Ultrastructure
The ultrastructure o f the choroid plexus papilloma (CPP) has been reported by Luse (1960), Carter et al., (1972), G h a t a k and M c W h o r t e r (1976), Milhorat et al. (1976), and Wolfson and Brown (1977) that in almost every point it is the same as in n o r m a l choroid plexus o f any species previously examined (Davis et al., 1973; Milhorat, 1977). We examined electron microscopically four cases o f CPPs obtained at the time o f surgical excision and c o m p a r e d them with n o r m a l choroid plexus (CP) o f mouse and chick. In this paper we describe the fusion o f the two outer leaflets o f the adjacent cytoplasmic membrane. There are some reports that CPPs have tight junctions at the apical end, as does CP, but the fusion has not yet been made clear till now.
Light microscopically our four cases were clearly choroid plexus papollomas (Fig. 1). General ultrastructural findings in 4 CPPs and normal CP o f mouse and chick were the same as previously described by other authors listed in the first part of this paper. In apical tight junctions fusion o f the outer leaflet of the two adjacent cytoplasmic membranes was clearly detected in uranyl acetate and ruthenium red block stained cases in choroid plexus papillomas as also in normal CP o f mouse and chick (Fig. 2). Since the study
Material and Methods Tissues obtained at the time of surgical excision and normal CP of mouse and chick were fixed by immersion in 2 % formaldehyde and 2.5 % glutaraldehyde in 0.1 M sodium cacodylate buffer (pH 7.3) for 4 h or overnight, and fixed in 1% OsO4 in 0.1 M sodium cacodylate buffer (pH 7.3) for 11/2 h or 1% OsO4 with 0.3 ~ ruthenium red for
Offprint requests to: Dr. S. Wakai (address see above)
Fig. 1. Choroid plexus papilloma. Single-layered columnar or high cuboidal cells arranged in a papillary pattern resembling normal choroid plexus. Pleomorphism and mitosis are not observed, H-E, x 198
0001-6322/79/0045/0159/$1.00
160
Acta Neuropathol. (Berl.) 45 (1979)
Fig. 2 Apical tight junction of the normal choroid plexus of mouse. Arrows indicate points of fusion of the two outer leaflets. Immersion in uranyl acetate before dehydration, x 80,000
Fig. 3 Apical tight junction of the choroid plexus papilloma. Arrows indicate points of fusion of the two adjacent cytoplasmic membranes. Ruthenium red. Immersion in uranyl acetate before dehydration, x 95,000
of the intimately apposed cell membranes of the nervous/system by Brightman and Reese (1969), it has been v,/ell known that in tight junctions fusion of the two outer leaflets of the adjacent cell membrane can be observed in the uranyl acetate block stained specimens by transmission electron microscopy. Until now it has not yet been clear whether in CPP the apical tight junction has true fusion of the two outer leaflets. In this report we made this fusion clear in four cases of choroid plexus papillomas. Therefore, it is speculated that CPP has the same barrier function (blood-CSF barrier) as normal CP has. In addition to this function, it is also speculated that our four cases of CPP have ability of CSF production based on electron microscopical features such as apical tight junctions described above, lysosomes and other structures observed also in normal CP (Milhorat et al., 1976; Milhorat, 1977; Ghatak and McWhorter, 1976). In the future the difference between tight junctions of the CPP and the CP may be revealed by freezefracturing technique. Acknowledgements.The authors wish to thank to Prof. T. Yohro and Dr. N. Hirokawa (Department of Anatomy) for their encouragement and valuable discussion.
References Brightman, M. W., Reese, T. S. : Junctions between intimately apposed cell membranes in the vertebrate brain. J. Cell Biol. 40, 6 4 8 - 677 (1969) Carter, L. P., Beggs, J., Waggener, J. D.: Ultrastructure of three choroid plexus papilloma. Cancer 30, 1130-1136 (1972) Davis, D. A., Lloyd, B. J., Jr., Milhorat, T. H.: A comparative ultrastructural study of the choroid plexuses of the immature pig. Anat. Rec. 176, 443-454 (1973) Ghatak, N. R., McWhorter, J. M. : Ultrastructural evidence for CSF production by a choroid plexus papilloma. J. Neurosurg. 45, 409-415 (1976) Luft, J. H.: Ruthenium red and violet. Anat. Rec. 171, 347-442 (1971) Luse, S. A. : Electron microscopic studies of brain tumor. Neurology (Minneap.) 10, 881-905 (1960) Milhorat, T. H., Davis, D. A., Hammock, M. K. : Choroid plexus papilloma. II. Ultrastructure and ultracytochemical localization of Na-K-ATPase. Childs Brain 2, 290-303 (1976) Milhorat, T. H. : Structure and function of the choroid plexus and other sites of cerebrospinal fluid formation. Int. Rev. Cytol. 47, 225-288 (1977) Wolfson, W. L., Brown, W. J.: Disseminated choroid plexus papilloma. Arch. Pathol. Lab. Med. 101, 366-368 (1977)
Received September 11, 1978/Accepted October 27, I978
Acta Neuropathol. (Berl.) 45, 159- 160 (1979)
Springer-Verlag 1979
Tight Junctions in Choroid Plexus Papillomas S. Wakai, M. Matsutani, H. Mizutani, and K. Sano Department of Neurosurgery, Faculty of Medicine, University of Tokyo, Hongo, Tokyo, 113 Japan
Summary. F o u r cases o f choroid plexus papilloma (CPP) obtained at the time o f surgical excision were examined by electron microscopy and c o m p a r e d with normal choroid plexus (CP) of mouse and chick. In apical tight junctions fusion o f the two outer leaflets o f the adjacent cytoplasmic m e m b r a n e was verified as in CP. This fact suggests that there is a b l o o d - C S F barrier not only in CP but also in CPP.
3 h (Luff, 1971), and then, or after immersion in 1% uranyl acetate for 2 h at room temperature, they were dehydrated in graded series of ethanols and embedded in Araldite or Epon. Histologic sections were prepared by standard laboratory procedures. Ultrathin sections were cut with an LKB ultramicrotome, stained both with uranyl acetate and lead citrate and examined in an Hitachi HU-I1DS electron microscope.
Results and Discussion Key words: Tight j u n c t i o n -- C h o r o i d plexus papill o m a - Ultrastructure
The ultrastructure o f the choroid plexus papilloma (CPP) has been reported by Luse (1960), Carter et al., (1972), G h a t a k and M c W h o r t e r (1976), Milhorat et al. (1976), and Wolfson and Brown (1977) that in almost every point it is the same as in n o r m a l choroid plexus o f any species previously examined (Davis et al., 1973; Milhorat, 1977). We examined electron microscopically four cases o f CPPs obtained at the time o f surgical excision and c o m p a r e d them with n o r m a l choroid plexus (CP) o f mouse and chick. In this paper we describe the fusion o f the two outer leaflets o f the adjacent cytoplasmic membrane. There are some reports that CPPs have tight junctions at the apical end, as does CP, but the fusion has not yet been made clear till now.
Light microscopically our four cases were clearly choroid plexus papollomas (Fig. 1). General ultrastructural findings in 4 CPPs and normal CP o f mouse and chick were the same as previously described by other authors listed in the first part of this paper. In apical tight junctions fusion o f the outer leaflet of the two adjacent cytoplasmic membranes was clearly detected in uranyl acetate and ruthenium red block stained cases in choroid plexus papillomas as also in normal CP o f mouse and chick (Fig. 2). Since the study
Material and Methods Tissues obtained at the time of surgical excision and normal CP of mouse and chick were fixed by immersion in 2 % formaldehyde and 2.5 % glutaraldehyde in 0.1 M sodium cacodylate buffer (pH 7.3) for 4 h or overnight, and fixed in 1% OsO4 in 0.1 M sodium cacodylate buffer (pH 7.3) for 11/2 h or 1% OsO4 with 0.3 ~ ruthenium red for
Offprint requests to: Dr. S. Wakai (address see above)
Fig. 1. Choroid plexus papilloma. Single-layered columnar or high cuboidal cells arranged in a papillary pattern resembling normal choroid plexus. Pleomorphism and mitosis are not observed, H-E, x 198
0001-6322/79/0045/0159/$1.00
160
Acta Neuropathol. (Berl.) 45 (1979)
Fig. 2 Apical tight junction of the normal choroid plexus of mouse. Arrows indicate points of fusion of the two outer leaflets. Immersion in uranyl acetate before dehydration, x 80,000
Fig. 3 Apical tight junction of the choroid plexus papilloma. Arrows indicate points of fusion of the two adjacent cytoplasmic membranes. Ruthenium red. Immersion in uranyl acetate before dehydration, x 95,000
of the intimately apposed cell membranes of the nervous/system by Brightman and Reese (1969), it has been v,/ell known that in tight junctions fusion of the two outer leaflets of the adjacent cell membrane can be observed in the uranyl acetate block stained specimens by transmission electron microscopy. Until now it has not yet been clear whether in CPP the apical tight junction has true fusion of the two outer leaflets. In this report we made this fusion clear in four cases of choroid plexus papillomas. Therefore, it is speculated that CPP has the same barrier function (blood-CSF barrier) as normal CP has. In addition to this function, it is also speculated that our four cases of CPP have ability of CSF production based on electron microscopical features such as apical tight junctions described above, lysosomes and other structures observed also in normal CP (Milhorat et al., 1976; Milhorat, 1977; Ghatak and McWhorter, 1976). In the future the difference between tight junctions of the CPP and the CP may be revealed by freezefracturing technique. Acknowledgements.The authors wish to thank to Prof. T. Yohro and Dr. N. Hirokawa (Department of Anatomy) for their encouragement and valuable discussion.
References Brightman, M. W., Reese, T. S. : Junctions between intimately apposed cell membranes in the vertebrate brain. J. Cell Biol. 40, 6 4 8 - 677 (1969) Carter, L. P., Beggs, J., Waggener, J. D.: Ultrastructure of three choroid plexus papilloma. Cancer 30, 1130-1136 (1972) Davis, D. A., Lloyd, B. J., Jr., Milhorat, T. H.: A comparative ultrastructural study of the choroid plexuses of the immature pig. Anat. Rec. 176, 443-454 (1973) Ghatak, N. R., McWhorter, J. M. : Ultrastructural evidence for CSF production by a choroid plexus papilloma. J. Neurosurg. 45, 409-415 (1976) Luft, J. H.: Ruthenium red and violet. Anat. Rec. 171, 347-442 (1971) Luse, S. A. : Electron microscopic studies of brain tumor. Neurology (Minneap.) 10, 881-905 (1960) Milhorat, T. H., Davis, D. A., Hammock, M. K. : Choroid plexus papilloma. II. Ultrastructure and ultracytochemical localization of Na-K-ATPase. Childs Brain 2, 290-303 (1976) Milhorat, T. H. : Structure and function of the choroid plexus and other sites of cerebrospinal fluid formation. Int. Rev. Cytol. 47, 225-288 (1977) Wolfson, W. L., Brown, W. J.: Disseminated choroid plexus papilloma. Arch. Pathol. Lab. Med. 101, 366-368 (1977)
Received September 11, 1978/Accepted October 27, I978
