Small fiber neuropathy is associated with the metabolic syndrome.
BACKGROUND
The etiology of sensory neuropathies is often not found. We tested the hypothesis that the metabolic syndrome (MS) may be associated with painful neuropathy, in the absence of frank diabetes.


METHODS
Clinical and quantitative neuropathy assessments were performed on 10 neuropathy patients with MS, 20 with MS with type 2 diabetes (10 recent onset and 10 of >5 years in duration), and 10 healthy, age-matched subjects. Intraepidermal nerve fiber density (IENF) and mean dendrite length (MDL) were determined by quantitative immunofluorescence on skin biopsies using antibody to PGP 9.5.


RESULTS
In metabolic syndrome, MDL was reduced and correlated negatively with sensory symptoms, signs, HDL-C, and sural nerve amplitude. The strongest inverse metabolic correlate of the metabolic syndrome neuropathy was HDL-C, which also correlated negatively with sensory symptoms, signs, and sural nerve amplitudes. The strongest metabolic correlate of diabetic sensorimotor neuropathy was HbA1c, which was associated with reduced IENF in patients with >5 years in duration of disease as well as reduced peroneal nerve amplitudes.


CONCLUSIONS
These data indicate that metabolic features, including HDL-C in metabolic syndrome, are associated with small fiber neuropathy and that MDL is an early marker of sensory neuropathy in patients with MS. Reductions in IENF reflect a longer duration of diabetes, with hyperglycemia leading to a sensorimotor neuropathy. These findings support the possibility that there is a sensory neuropathy with reduced intraepidermal nerve fiber length, which cosegregates with features of metabolic syndrome.
Pittenger
Gary L
GL
The Strelitz Diabetes Institutes, Department of Internal Medicine, and Department of Pathology and Anatomy, Eastern Virginia Medical School, Norfolk, Virginia.
Mehrabyan
Anahit
A
Simmons
Kathryn
K
Amandarice
Dublin
Charlotte
C
Barlow
Patricia
P
Vinik
Aaron I
AI