The blood–brain barrier is playing a critical role in controlling the influx and efflux of
biological substances essential for the brain's metabolic activity as well as neuronal function …

Tight junctions (TJs) are intercellular junctions critical for building the epithelial barrier and
maintaining epithelial polarity. The claudin family of membrane proteins play central roles in …

Proteins and peptides (PPs) have gradually become more attractive therapeutic molecules
than small molecular drugs due to their high selectivity and efficacy, but fewer side effects …

The presence of barriers, such as the blood–brain barrier (BBB) and brain–tumor barrier
(BTB), limits the penetration of antineoplastic drugs into the brain, resulting in poor response …

A fundamental function of the intestinal epithelium is to act as a barrier that limits interactions
between luminal contents such as the intestinal microbiota, the underlying immune system …

Spermatogenesis is the cellular process by which spermatogonia develop into mature
spermatids within seminiferous tubules, the functional unit of the mammalian testis, under …

Claudins are tight junction membrane proteins that are expressed in epithelia and
endothelia and form paracellular barriers and pores that determine tight junction …

Maintaining a healthy gut environment is a prerequisite for sustainable animal production.
The gut plays a key role in the digestion and absorption of nutrients and constitutes an initial …

The gastrointestinal epithelium forms the boundary between the body and external
environment. It effectively provides a selective permeable barrier that limits the permeation …

Intercellular tight junctions represent a formidable barrier against paracellular drug
absorption at epithelia (eg, nasal, intestinal) and the endothelium (eg, blood–brain barrier) …