Objective: Interstitial fluid in extracellular matrices may not be totally fixed but partially flow through long-distance oriented fibrous connective tissues via physical mechanisms. We hypothesized there is a long-distance interstitial fluid transport network beyond vascular circulations.
Materials and methods:We first used 20 volunteers to determine hypodermic entrant points to visualize long-distance extravascular pathway by MRI. We then investigated the extravascular pathways initiating from the point of thumb in cadavers by chest compressor. The distributions and structures of long-distance pathways from extremity ending to associated visceral structures were identified.Results: Using fluorescent tracer, the pathways from right thumb to right atrium wall near chest were visualized in seven of 10 subjects. The cutaneous pathways were found in dermic, hypodermic and fascial tissues of hand and forearm. The perivascular pathways were along the veins of arm, axillary sheath, superior vena cava and into the superficial tissues on right atrium. Histological and micro-CT data showed these pathways were neither blood nor lymphatic vessels but long-distance oriented fibrous matrices, which contained the longitudinally assembled micro-scale fibres consistently from thumb to superficial tissues on right atrium.
Lead (Pb) is a well-known neurotoxicant and a risk factor for neurologic disorders. The blood brain barrier (BBB) plays an important role in the maintenance of optimal brain function. BBB is a target of Pb, and studies have shown that Pb induced barrier loss and decreased the expression of tight junction proteins, but the detailed mechanisms are not fully understood. Matrix metalloproteinases (MMPs) are important components of extracellular matrix proteasome and can affect the remodeling and degradation of tight junction (TJ). The role of MMP-2/9 in Pb-induced damage of BBB is not known. In our study, we used an in vitro BBB model by co-culturing human umbilical vascular endothelial cells (ECV304 cells) with rat glioma cells (C6 cells), and detected the expression of related TJ proteins and MMP-2/9. Our results showed that Pb increased the permeability of the in vitro BBB model, and stimulating C6 cells with Pb could decrease the protein level of ZO-1 (zonula occludens-1) and occludin in ECV304 cells. Pb could increase the mRNA and protein level of MMP-2/9 in C6 cells, and inhibition of MMP-2/9 by SB-3CT could partially alleviate Pb-induced down-regulation of TJ proteins in ECV304 cells and Pb-induced barrier damage in the in vitro BBB model. Our research established potential therapeutic targets for modulating and preserving optimal BBB function.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.