Increased sural nerve epineurial blood flow in human subjects with painful diabetic neuropathy.
OBJECTIVE
The pathogenesis of painful diabetic neuropathy remains unknown. As a consequence we still do not have any effective, rational treatments and a greater understanding of the mechanisms is urgently required. Previous studies have shown no consistent morphological differences in the nerves of patients with and without painful neuropathy. The aim of this study was to compare epineurial haemodynamics in patients with chronic painful and painless neuropathy.


METHODS
The techniques of microlightguide spectrophotometry and fluorescein angiography were used to measure epineurial intravascular oxygen saturation and blood flow respectively. Eleven patients with painful and eight with painless neuropathy were studied, with the groups matched carefully in terms of severity of neuropathy and diabetes control.


RESULTS
Intravascular oxygen saturation was higher in the painful neuropathy group compared to those without pain (median 73.8% vs 67.7%, respectively; p=0.021). Fluorescein rise time was also faster in those with painful symptoms (median 18.3 s vs 53.6 s; p=0.046) indicating higher epineurial blood flow in these subjects.


CONCLUSIONS
These results indicate that there are distinct differences in haemodynamics within the epineurium of the sural nerve in subjects with painful and painless neuropathy. Haemodynamic factors could therefore have an important role in the pathogenesis of neuropathic pain and might offer further insight into potential treatments for this distressing condition.
Eaton
S E M
SE
Diabetes Research Unit, Royal Hallamshire Hospital, Glossop Road, Sheffield, UK.
Harris
N D
ND
Ibrahim
S
S
Patel
K A
KA
Selmi
F
F
Radatz
M
M
Ward
J D
JD
Tesfaye
S
S
D001783:Blood Flow Velocity; D003922:Diabetes Mellitus, Type 1 / Q000503:physiopathology; D003924:Diabetes Mellitus, Type 2 / Q000503:physiopathology; D003929:Diabetic Neuropathies / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009046:Motor Neurons / Q000502:physiology; D009431:Neural Conduction / Q000502:physiology; D009437:Neuralgia / Q000503:physiopathology*; D009475:Neurons, Afferent / Q000502:physiology; D010100:Oxygen / Q000097:blood; D010543:Peroneal Nerve / Q000503:physiopathology*; D012039:Regional Blood Flow; D013497:Sural Nerve / Q000098:blood supply* / Q000503:physiopathology
D010100:Oxygen