Effect of glycemic control on sudomotor denervation in type 2 diabetes.
OBJECTIVE
Sudomotor symptoms are a common component of diabetic autonomic neuropathy, but the pathology of sudomotor innervation and its relationship with glycemic control have remained obscured.


METHODS
We enrolled 42 patients (26 males and 16 females aged 56.64 ± 12.67 years) with diabetic neuropathy defined by symmetric distally predominant sensory symptoms, abnormal nerve conduction studies, and reduced intraepidermal nerve fiber density in the leg. Skin biopsies of the distal leg were immunostained with antiprotein gene product 9.5 for nerve fibers and counterstained with Congo red for sweat glands. Sweat gland innervation index (SGII) was quantified with a new computerized area-based morphometric system.


RESULTS
Protein gene product 9.5(+) nerve terminals surrounded secretory coils of the sweat glands in the skin of control subjects. Sudomotor denervation was present in diabetic patients, manifesting as depletion of periglandular nerve fibers with lower SGII compared with 42 age- and sex-matched control subjects (2.54 ± 1.87 vs. 4.68 ± 1.51%, P < 0.001). The SGII was correlated with HbA(1c) (P = 0.011) and was lower in patients with anhidrosis of the feet compared with those with normal sweating of the feet (0.82 ± 0.69 vs. 3.00 ± 1.81%, P = 0.001). Sudomotor denervation was concordant with cardiac autonomic dysfunction as assessed with reduced heart rate variability (P = 0.003).


CONCLUSIONS
Sudomotor denervation is a significant presentation of diabetic neuropathy, and the SGII was associated with HbA(1c). A skin biopsy offers a structural assessment of sudomotor innervation.
Department of Anatomy and Cell Biology, College of Medicine, National Taiwan University, Taipei, Taiwan.
Kai-Ren
KR
Luo
Chi-Chao
CC
Chao
Paul-Chen
PC
Hsieh
June-Horng
JH
Lue
Sung-Tsang
ST
Hsieh
D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000378:metabolism* / Q000502:physiology; D003924:Diabetes Mellitus, Type 2 / Q000097:blood*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009412:Nerve Fibers / Q000473:pathology* / Q000502:physiology*; D011446:Prospective Studies; D012867:Skin / Q000294:innervation; D013545:Sweat Glands / Q000294:innervation
D001786:Blood Glucose