Localization of TrkB and p75 receptors in peritoneal and deep infiltrating endometriosis: an immunohistochemical study

摘要

Background The roles of the neurotrophins NGF (Neurotrophic growth factor) and BDNF (brain-derived neurotrophic factor) in neuronal growth and development are already known. Meanwhile, the neurotrophin receptors TrkA (tropomyosin related kinase A), TrkB, and p75 are important for determining the fate of cells. In endometriosis, this complex system has not been fully elucidated yet. The aim of this study was to evaluate the expression and location of these neurotrophins and their receptors in peritoneal (PE) and deep infiltrating endometriotic (DIE) tissues and to measure and compare the density of nerve fibers in the disease subtypes. Methods PE lesions ( n =?20) and DIE lesions ( n =?22) were immunostained and analyzed on serial slides with anti-BDNF, ?NGF, ?TrkA, ?TrkB, ?p75,-protein gene product 9.5 (PGP9.5, intact nerve fibers) and -tyrosine hydroxylase (TH, sympathetic nerve fibers) antibodies. Result There was an equally high percentage (greater than 75?%) of BDNF-positive immunostaining cells in both PE and DIE. TrkB (major BDNF receptor) and p75 showed a higher percentage of immunostaining cells in DIE compared to in PE in stroma only ( p Conclusions While the neurotrophin BDNF is equally present in PE and DIE, its receptors TrkB and p75 are more highly expressed in DIE and may have a potential role in the pathophysiology of DIE, especially in promotion of cell growth. BDNF has a stronger binding affinity than NGF to the p75 receptor, likely inducing sympathetic nerve axonal pruning in DIE, resulting in the lower nerve fiber density seen.