Pupillocynetic activity of substance P in systemic sclerosis.
OBJECTIVE
In systemic sclerosis (SSc), dysfunctions of peripheral nervous system (PNS) have been observed. Substance P (SP) instillation in human eye induces a cholinergic-independent pupil myosis. Pupil basal diameters (PBD) and pupil responsiveness to SP, expressed as area under the curve (AUC), were studied by pupillometry to assess SP-ergic fiber state and function in SSc.


METHODS
Forty SSc patients [24 with limited (lSSc), 16 with diffuse (dSSc) disease] and 40 controls underwent pupillometric evaluation. After evaluation of PBD, SP 10-3 M was instilled in one eye and placebo in the contralateral eye. Antinuclear (ANA), anticentromere (ACA), and anti-Scl-70 autoantibodies were correlated with PBD and AUC.


RESULTS
PBD was significantly lower in SSc patients versus controls (p < 0.001). PBD was minor in lSSc versus both dSSc and controls (p < 0.05), but no difference was found between dSSc and controls. In SSc, SP 10-3 M induced greater myosis compared to controls (p < 0.001). SP 10-3 M-induced myosis was higher in lSSc versus both dSSc and controls (p < 0.05). ACA significantly correlated with decreased values of PBD and AUC (p < 0.001).


CONCLUSIONS
Our results show that PBD is reduced in patients with SSc and that SP induces a more intense myosis in SSc than controls. Moreover, in lSSc PBD is lower and SP increases the myosis in lSSc compared to dSSc and controls. This suggests a peculiar dysfunction of PNS in patients with the limited subset of SSc.
Del Rosso
Angela
A
Department of Medicine, Section of Rheumatology, Headache, and Nephrology, University of Florence, Italy.
Bertinotti
Luca
L
Pietrini
Umberto
U
Messori
Andrea
A
Fanciullacci
Marcello
M
Casale
Roberto
R
Giacomelli
Roberto
R
Generini
Sergio
S
Sicuteri
Riccardo
R
Pignone
Alberto
A
Cozzi
Franco
F
Matucci-Cerinic
Marco
M
D000368:Aged; D001323:Autoantibodies / Q000032:analysis; D005260:Female; D006801:Humans; D007498:Iris / Q000294:innervation; D008297:Male; D008875:Middle Aged; D009475:Neurons, Afferent / Q000187:drug effects / Q000502:physiology; D011680:Pupil; D012025:Reflex, Pupillary / Q000187:drug effects*; D012595:Scleroderma, Systemic / Q000175:diagnosis* / Q000276:immunology / Q000503:physiopathology*; D013373:Substance P
D001323:Autoantibodies; D013373:Substance P