Lendothélium

Lendothélium is a term used in speculative biology and in some science fiction contexts to describe a specialized lining tissue proposed to form the inner surface of certain luminal spaces, combining features of endothelial and epithelial tissues. In these concepts, lendothélium acts as a barrier and interface between circulating fluids and surrounding compartments, sometimes spanning channels that resemble blood vessels or tissue cavities.

Histological descriptions in speculative models commonly depict lendothélium as a contiguous sheet of polygonal cells that may be monolayer or lightly stratified. Cells are linked by tight and adherens junctions and rest on a basal lamina. The surface often bears microvilli or other projections to modulate exchange with the lumen, and a glycocalyx-like layer may be present. The tissue is envisioned to express a mix of adhesion molecules and signaling receptors found in both endothelial and epithelial lineages, supporting selective permeability and mechanosensing.

Proposed functions include regulation of fluid and solute exchange, immune signaling, and coordination of local repair processes after injury. Some models also suggest roles in sensing shear stress, controlling microenvironmental chemistry, or guiding cell trafficking within luminal spaces.

Occurrence and status: lendothélium is not recognized as a distinct tissue type in mainstream biology and is mostly found in speculative frameworks or fictional literature. Its definitions and markers vary, and there is limited empirical support. In legitimate research, the term remains controversial and is generally treated as a hypothetical construct requiring rigorous validation.

See also: endothelium; epithelium; basement membrane; barrier tissue.