Parenchima innervation of human white adipose tissue studied by digital deconvolution,for optical three-dimensional reconstruction of fluorescent imagines and transmission electron microscopy

In humans there is a lack of morphological evidence of white adipose tissue (WAT) innervation also if electrophysiological study in human suggests it. Therefore we search for parenchyma innervation of human subcutaneous WAT by fluorescence immunohistochemistry for protein gene product 9.5 (PGP 9.5) a pan axonal marker. Considering the low percentage of adipocytes innervated, we use digital deconvolution of wide-field fluorescence threedimensional image stacks of thick sections .We employed Transmission Electron Microscopy (TEM) to examine at high resolution the morphology of nerve fiber terminal and neuroeffector junction in adipose tissue. We use an indirect immunofluorescence method to show nerve fibers immunoreactive in frozen sections .The primary antibody employed was a Rabbit anti- PGP 9.5 before characterized. For immunofluorescence we utilized a sample of skin taken in the course of a diagnostic quadriceps muscle biopsy from an adult patient (age: 40 years) and 3 archival skin biopsies from the child’s forearm (age 1–3 years) , for TEM observation. PGP .9.5 immunoreactive varicose nerve fibers appear in close apposition with single adipocyte. The nerve fibers often were at the boundary between flanking adipocytes and unrelated from contiguous blood vessels .Tem observation shows unmyelinated nerve fibers near single adipocytes. Terminal axons containing mostly small dense core vesicles face fat cell membrane, which did not present any specialization.Our results show the existence in human WAT of a parenchyma innervation for the first time. The innervation is already present in children adipose tissue and appears unambiguously of adrenergic type from ultrastrucure.