Skull diploë is rich in aquaporin-4

Yuji Suzuki, Hiroki Kitaura, Yukimi Nakamura, Akiyoshi Kakita, Vincent J. Huber, Nicholas Capozzoli, Ingrid L. Kwee, Tsutomu Nakada

Research output: Contribution to journalArticlepeer-review


Aquaporin-4 (AQP4) is a water conducting membrane integral protein channel which is widely expressed in the astrocyte system of the brain. During the development of the AQP4 positron emission tomography (PET) imaging agent [11C]TGN-020 (N-(1,3,4-thiadiazol-2-yl)pyridine-3-[11C]-carboxamide), significant radioligand uptake was observed in the skull, where there was no known distribution of any aquaporin family proteins. Herein we confirmed via a newly developed method for bone-tissue immunohistology, a hitherto unrecognized distribution of AQP4, and not AQP1, in the skull. Other bony structures, by contrast, showed virtually no uptake of [11C]TGN-020, and likewise, do not express either AQP4 or AQP1. Immunohistological analysis demonstrated that the AQP4 expression in the skull is restricted to the diploë. Consequently, we suspect AQP4 plays a pivotal role in the formation and maintenance of yellow marrow and the diploë. However, elucidating the exact nature of that role will require further studies. Anatomy; Pathology; Medical imaging; Nuclear medicine; Radiology; Tissue culture; Bone; Aquaporin 4 (AQP4); Skull; Positron emission tomography(PET); N-(1,3,4-thiadiazol-2-yl) pyridine-3-[11C]-carboxamide ([11C]TGN-020); Immunohistology.

Original languageEnglish (US)
Article numbere03259
Issue number1
StatePublished - Jan 2020


  • Anatomy
  • Aquaporin 4 (AQP4)
  • Bone
  • Immunohistology
  • Medical imaging
  • N-(1,3,4-thiadiazol-2-yl) pyridine-3-[11C]-carboxamide ([11C]TGN-020)
  • Nuclear medicine
  • Pathology
  • Positron emission tomography(PET)
  • Radiology
  • Skull
  • Tissue culture

ASJC Scopus subject areas

  • General


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