Objective: To evaluate mechanisms underlying diabetic neuropathy (DN) progression using indices of sural nerve morphometry obtained from two identical randomized placebo-controlled clinical trials.
Research Design and Methods: Sural nerve myelinated fiber density (MFD), nerve conduction velocities, vibration perception thresholds, clinical symptom scores and a visual analogue scale for pain were analyzed in participants with DN. A losee of 500 or more fibers/mm(2) in sural nerve MFD over 52 weeks was defined as progressing DN and a MFD loss of 100 or less fibers/mm(2) during the same time interval as non-progressing DN. The progressing and non-progressing cohorts were matched for baseline characteristics using an O'Brien rank sum and baseline MFD.
• At 52 weeks, the progressing cohort demonstrated a 25% decrease (p < 0.0001) from baseline in myelinated fiber density while the non-progressing cohort remained unchanged.
• Myelinated fiber density was not affected by active drug treatment (p=0.87), diabetes duration (p=0.48), age (p=0.11) or body mass index (BMI) (p=0.30).
• Among all variables tested, elevated triglycerides and decreased peroneal motor NCV at baseline significantly correlated with loss of myelinated fiber density at 52 weeks (p=0.04).
Conclusions: In this cohort of participants with mild/moderate DN, elevated triglycerides correlated with myelinated fiber density loss independent of disease duration, age, diabetes control or other variables. [Note: Dietitians advise that triglycerides, made in the liver from excess sugar not used for energy production, may be controlled by eliminating simple sugar in the diet.]
These data support the evolving concept that hyperlipidemia is instrumental in the progression of diabetic neuropathy.
Source: Diabetes, May 1, 2009. PMID: 19411614, by Wiggin TD, Sullivan KA, Pop-Busui R, Amato A, Sima AA, Feldman EL. University of Michigan Department of Neurology. [E-mail: firstname.lastname@example.org]