Background: Anchoring fibrils were initially described as the arch-like structures that extend from the lamina densa to the sub-lamina densa. Keene et al. proposed a model in which the anchoring fibrils bridge structures called "anchoring plaques", and thus the three-dimensional (3D) structure of the anchoring fibrils remains somewhat controversial.
Objective: The aim of this study is to elucidate the 3D structure of anchoring fibrils in the skin.
Methods: In the present study, we performed electron microscopic 3D reconstruction of the epidermal-dermal junction, including the anchoring fibrils and hemidesmosomes using a personal computer and NIH-image software.
Results: We obtained images showing that anchoring fibrils had both ends inserted into the lamina densa and that interstitial dermal collagen fibers passed through the loops of the anchoring fibrils. "Anchoring plaques" were not observed. Clear images of hemidesmosomal distribution were not obtained due to technical limitations.
Conclusion: These results suggest that the loops of the anchoring fibrils are the most important primary structures that hold the dermal interstitial collagen fibers and bind the basement membrane to the dermis.