Role of pericytes in the barrier task

Abstract The function of endothelial-blood/tissue barrier is critical for maintaining and controlling tissue homeostasis. The blood-retinal barrier (BRB) is a blood-ocular barrier system, made up of an inner and an outer barrier. BRB is located in the retinal microvasculature and include the microvascular endothelium. The role of the BRB is to control molecule trafficking: ion, protein and water flux, from the blood to the retina. Another barrier is the cochlear blood-labyrinth-barrier, located in the stria vascularis (intrastrial fluid-blood barrier) that controls the permeability and maintains a stable homeostatic system in the inner ear, between the systemic circulation and the fluids inside the stria vascularis, by regulatory mechanisms that are, however, largely unknown. The blood-labyrinth barrier in the stria vascularis is anatomically different from the blood barriers in the retina. In contrast to the high degree of vascularization and loose association with surrounding non vascular tissue present in other barriers, the blood-labyrinth barrier is a multi-layer barrier with a network of dense capillary system of marginal epithelial cells with surrounding pericyte cells (PCs) and a basement membrane of mesodermal basal cells, interconnected by tight junctions. In both barriers the PCs have a crucial role: their functions are linked to regulating cerebral blood flow, barrier permeability, cerebral vascular formation maintenance and regulating. It was seen that PCs are involved in vascular development, integrity, angiogenesis and tissue fibrogenesis. The loss of PCs contributes to the pathogenesis of many disorders such as an early feature of diabetic retinopathy, characterised by retinal microvascular dysfunction and degeneration in the BRB. In the physiology of the cochlea, PCs play a role in numerous cochlear pathologies, including, but not limited to, sudden sensorineural hearing loss, acoustic trauma, and inflammation of the cochlea. Understanding the role of PCs in pathophysiology, particularly how it relates to microvascular degeneration and pathological neovascularisation, is critical in order for the development of novel therapies to complement, or improve upon, current treatment options. This research evaluates the potential of human adipose stem cells (hASCs) in differentiating into the phenotype of PCs and examines the effects of hASC like-pericytes on human retinal endothelial cells (hRECs) for barrier formation by measuring trans-endothelial electric resistance and by immuno-analysis. Therefore, adipose stem cells-based therapeutic approaches may be usefully exploited to restore retinal microvasculature integrity. A second study was carried out to obtain and cultivate primary bovine cochlear pericytes (BCPs) and to test the effects of some ototoxic drugs on these BCPs. The use of BCPs for the analysis of ototoxic drugs can be a model to investigate pharmacological mechanisms and protection systems against different insults.