Intermediate filament typing of the human embryonic and fetal notochord

Abstract

In order to characterize human notochordal tissue we investigated notochords from 32 human embryos and fetuses ranging between the 5th and 13th gestational week, using immunohistochemistry to detect intermediate filament proteins cytokeratin, vimentin and desmin, the cytokeratin subtypes 7, 8, 18, 19 and 20, epithelial membrane antigen (EMA), and adhesion molecules pan-cadherin and E-cadherin. Strong immunoreactions could be demonstrated for pan-cytokeratin, but not for desmin or EMA. Staining for pan-cadherin and weak staining for E-cadherin was found on cell membranes of notochordal cells. Also it was demonstrated that notochordal cells of all developmental stages contain the cytokeratins 8, 18 and 19, but not 7 or 20. Some cells in the embryonic notochord also contained some vimentin. Vimentin reactivity increased between the 8th and 13th gestational week parallel to morphological changes leading from an epithelial phenotype to the chorda reticulum which represents a mesenchymal tissue within the intervertebral disc anlagen. This coexpression reflects the epithelial-mesenchymal transformation of the notochord, which also loses E-cadherin expression during later stages. Our findings cannot elucidate a histogenetic germ layer origin of the human notochord but demonstrate its epithelial character. Thus, morphogenetic inductive processes between the human notochord and its surrounding vertebral column anlagen can be classified as epithelial-mesenchymal interactions.

Expression of E-cadherin in chordomas: diagnostic marker and possible role of tumor cell affinity

“…These results suggest that the cellular adhesion of chordomas is dominantly mediated by a Ca 2+ -dependent mechanism, and this character may organize the morphological constructs, such as intra-tumorous calcification, noted occasionally in chordomas. Previous immunohistochemical analysis of human embryos revealed expression of E-cadherin in the embryos younger than 9 weeks, although it disappeared in notochords from specimens older than 10-11 weeks [6]. Since chordoma is speculated to originate from the remnants of the embryonic notochord, expression of E-cadherin in chordoma cells seems to simulate that of early to middle embryonic notochordal cells.…”

The Role Of Extracellular Matrix Elasticity and Composition In Regulating the Nucleus Pulposus Cell Phenotype in the Intervertebral Disc: A Narrative Review

“…Cells within the developing and immature NP are derived from embryonic notochord [15, [22][23][24], and exhibit morphologic features that refiect this unique embryonic origin: notochordal NP cells are large in diameter [25][26][27] containing large intracellular vacuoles, are organized in interconnected cell clusters, and exhibit strong cell-cell interactions characterized by gap junctions [26,27], cadherins [28][29][30], and desmosomal cellcell adhesions [31,32]. Recent characterizations of immature NP cells (bovine, rat, juvenile human) via cDNA microarrays, now cytometry, real time PCR, and immunohistochemistry, have identified new phenotype markers that are specific to immature NP cells (Table 1, specific references displayed in table) [28,[33][34][35][36].…”

Comparative study of shape, course, and disintegration of the rostral notochord in some vertebrates, especially humans

“…The formation and composition of the notochordal sheath was particularly investigated by Mookerjee (1953), Carlson and Low (1971), Frederickson and Low (1971), Carlson (1973), Bancroft and Bellairs (1976), Carlson and Kenney (1980), Götz et al (1995). The phenomenon of segmental flexures of the notochord was discussed by Baur (1967), Verbout (1971), Adams et al (1990).…”