Peripheral Autonomic Neuropathy: Diagnostic Contribution of Skin Biopsy

Abstract

Skin biopsy has gained widespread use for the diagnosis of somatic small-fiber neuropathy, but it also provides information on sympathetic fiber morphology. We aimed to ascertain the diagnostic accuracy of skin biopsy in disclosing sympathetic nerve abnormalities in patients with autonomic neuropathy. Peripheral nerve fiber autonomic involvement was confirmed by routine autonomic laboratory test abnormalities. Punch skin biopsies were taken from the thigh and lower leg of 28 patients with various types of autonomic neuropathy for quantitative evaluation of skin autonomic innervation. Results were compared with scores obtained from 32 age-matched healthy controls and 25 patients with somatic neuropathy. The autonomic cutoff score was calculated using the receiver operating characteristic curve analysis. Skin biopsy disclosed a significant autonomic innervation decrease in autonomic neuropathy patients versus controls and somatic neuropathy patients. Autonomic innervation density was abnormal in 96% of patients in the lower leg and in 79% of patients in the thigh. The abnormal findings disclosed by routine autonomic tests ranged from 48% to 82%. These data indicate the high sensitivity and specificity of skin biopsy in detecting sympathetic abnormalities; this method should be useful for the diagnosis of autonomic neuropathy, together with currently available routine autonomic testing.

Chronic stress, sympathetic activation and skeletal metastasis of breast cancer cells

“…48 These effects of sympathetic nerves on primary tumors are consistent with the known innervation of the prostate, 49,50 ovaries 51 and the skin. 52 It is still unclear whether these direct effects of catecholamines on primary tumor cells have any repercussion on their ability to disseminate to secondary sites, although studies on prostate and ovarian cancer support a role for the b2AR and b3AR in tumor development and dissemination to distant organs. 42,53 It is possible that the activation of sympathetic nerves in the primary tumor leads not only to increased tumor growth but also to Influence of neuroendocrine factors on breast cancer bone metastasis F Elefteriou remodeling of the host stroma to lead to a tissue, cell and cytokine profile that is favorable for cancer cell egress and dissemination to distant organs.…”

Skin nerve α-synuclein deposits

“…Autonomic innervation density was quantified using the previously described automated method showing a high Table 2 Laboratory findings Skin innervation score interobserver and intraobserver reliability. 16,19 Briefly, this method is based on a technique known as the "unsharp mask filter," which creates a composite image by subtracting the background color in the out-of-focus image from the base image expressing the autonomic innervation staining (Image-Pro Plus; Media Cybernetics, Rockville, MD). Target autonomic structures included muscle arrector pilorum (MAP) and sweat gland (SG).…”

“…Twelve free-floating sections were incubated overnight with a panel of primary antibodies, including the mouse or rabbit panneuronal marker protein gene product (PGP) 9.5 (1:800; Biogenesis, Poole, UK), mouse collagen IV (1:800; Chemicon, Temecula, CA), and autonomic markers such as rabbit dopamine-b-hydroxylase (DbH) (1:150; Chemicon) to identify the noradrenergic fibers 17 and rabbit vasoactive intestinal peptide (VIP) (1:1,000; Incstar, Stillwater, MN), colocalized in the sudomotor cholinergic fibers. 16 Sections were then washed and secondary antibodies, labeled with cyanine dye fluorophores 2 and 3.18 (1:400; Jackson ImmunoResearch, West Grove, PA), were added for an overnight incubation (see Donadio et al 18 for further details). Sections were initially viewed under a Zeiss fluorescent microscope (model Axioskop 40; Zeiss, Jena, Germany).…”

“…The corresponding innervations were quantified by PGP staining, which provided a stronger staining easier to quantify than the specific autonomic markers, but which was correlated with the innervation quantified by the specific autonomic markers. 16 Autonomic innervation score in each skin site usually represented the mean of 3 different target structures. Epidermal nerve fiber density (number of unmyelinated fibers per linear millimeter of epidermis) was calculated by considering a single epidermal nerve fiber marked by PGP 9.5 crossings of the dermal-epidermal junction.…”

“…The second skin sample was taken in all skin sites of patients with IPD (i.e., cervical, thigh, and leg) but only in the cervical site in controls and PAR patients. According to previously published procedures, 16 skin samples were immediately fixed in cold Zamboni fixative and kept at 4°C overnight.…”