Submitted by Nandita Keole, MD, News Science Editorial Board
Edited by Francisco Gomez, MD, News Science Editorial Board
Over the past several months, an ever increasing number of articles on biomarkers have been published. The AANEM News Science Editorial Board is striving to keep our readers abreast of these recent discoveries.
In “Rise of the Biomarkers – Part 4” (final segment of the biomarker series), researchers analyze skin biopsies of patients with diabetes mellitus (with and without diabetic neuropathy) and make some important discoveries.
Doppler K, Frank F, Koschker AC, Reiners K, Sommer C. Nodes of Ranvier in skin biopsies of patients with diabetes mellitus. Journal of the Peripheral Nervous System
2017 Sep. 22(3): 182-190.
Paranodal demyelination has been discussed as a potential mechanism of nerve fiber damage in diabetes mellitus (DM). In this study, the research team analyzed small and large fiber pathology in skin biopsies of patients with DM with and without diabetic neuropathy (DNP) (patients were classified into these subcategories based on established clinical criteria).
Myelinated nerve fibers of skin biopsies of 35 patients with DNP, 17 patients with DM without neuropathy and 30 normal controls were analyzed. Based on sural nerve NCS and the neurological examination, 30/35 patients with DNP were classified as having small and large fiber neuropathy and 5 were categorized as having small fiber neuropathy. Neither nodal/paranodal changes nor loss of myelinated nerve fibers were correlated with age (DNP patients were older).
Immunofluorescence of skin sections with antibodies against Caspr, neurofascin, Na channels and myelin basic protein was performed to analyze nodal structure, segmental demyelination, and nerve fiber myelination. There was an increase in elongated Ranvier nodes and dispersion of neurofascin in DM patients with and without neuropathy and in fingers of patients with DNP supporting the idea that paranodal pathology may precede neuropathy in DNP. The authors also concluded that neurofascin may be a more sensitive marker of paranodal changes than Caspr.
This study had a small sample size. Further studies with larger sample sizes including patients with more severe diseases might be helpful as sometimes pathology may precede overt clinical manifestations of DNP. However, DNP does seem strongly correlated with demonstrable nodal changes.