Aging-associated sensory neuropathy alters pressure-induced vasodilation in humans.
Healthy skin is protected from pressure-induced ischemic damage because of the presence of pressure-induced vasodilation (PIV). PIV relies on small sensory nerve fibers and endothelial function. Since aging alters both nervous and vascular functions, we hypothesized that PIV is altered with aging. We compared PIV in non-neuropathic and neuropathic older subjects (60-75 years) with that of young subjects (20-35 years). Laser Doppler flowmetry was used to evaluate the cutaneous responses to local pressure application, acetylcholine, and local heating. Quantitative sensory tests were used to evaluate sensory-nerve-fiber function. The non-neuropathic older subjects had an impaired PIV (12+/-7% increase in blood flow with pressure) compared with young subjects (62+/-4%, P<0.001). In the presence of peripheral neuropathy, the older subjects were totally deprived of PIV, leading to early pressure-induced cutaneous ischemia (-31+/-10%, P<0.001). This inability of the skin to adapt to localized pressure in older subjects is related to the severity of the sensory-fiber dysfunction rather than to endothelial dysfunction, which was comparable between the non-neuropathic (141+/-19% increased blood flow with acetylcholine, P<0.05) and neuropathic older subjects (145+/-28% increase, P<0.05) compared with young subjects (234+/-25% increase).
Fromy
Bérengère
B
Neurovascular Interactions, FRE CNRS 3075, University Claude Bernard Lyon 1, Département de Physilogie, Lyon, France. berengere.fromy@recherche.univ-lyon1.fr
Sigaudo-Roussel
Dominique
D
Gaubert-Dahan
Marie-Line
ML
Rousseau
Pascal
P
Abraham
Pierre
P
Benzoni
Daniel
D
Berrut
Gilles
G
Saumet
Jean Louis
JL
D000109:Acetylcholine / Q000008:administration & dosage; D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D005260:Female; D006358:Hot Temperature; D006801:Humans; D007511:Ischemia / Q000503:physiopathology; D017078:Laser-Doppler Flowmetry; D008297:Male; D008875:Middle Aged; D009599:Nitroprusside / Q000008:administration & dosage; D010523:Peripheral Nervous System Diseases / Q000503:physiopathology*; D011312:Pressure / Q000009:adverse effects; D003668:Pressure Ulcer / Q000503:physiopathology*; D011984:Sensory Receptor Cells / Q000502:physiology*; D012867:Skin / Q000098:blood supply / Q000294:innervation / Q000503:physiopathology; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology*; D014665:Vasodilator Agents / Q000008:administration & dosage
D014665:Vasodilator Agents; D009599:Nitroprusside; D000109:Acetylcholine