Evaluation of dermal myelinated nerve fibers in diabetes mellitus

Skin biopsies have primarily been used to study the non‐myelinated nerve fibers of the epidermis in a variety of neuropathies. In this study, we have expanded the skin biopsy technique to glabrous, non‐hairy skin to evaluate myelinated nerve fibers in the most highly prevalent peripheral nerve disease, diabetic polyneuropathy (DPN). Twenty patients with DPN (Type I, n = 9; Type II, n = 11) and 16 age‐matched healthy controls (age 29–73) underwent skin biopsy of the index finger, nerve conduction studies (NCS), and composite neuropathy scoring. In patients with DPN, we found a statistically significant reduction of both mechanoreceptive Meissner corpuscles (MCs) and their afferent myelinated nerve fibers (p = 0.01). This myelinated nerve fiber loss was correlated with the decreased amplitudes of sensory/motor responses in NCS. This study supports the utilization of skin biopsy to quantitatively evaluate axonal loss of myelinated nerve fibers in patients with DPN.