The wrinkles soothing effect on the middle and lower face by intradermal injection of botulinum toxin type A.
BACKGROUND
Botulinum toxin type A (BTA) has been used on facial expressive muscles to reduce wrinkles. We assumed that intradermal injection with BTA on the middle and lower face can produce face-lifting and wrinkles-soothing effect by promoting collagen synthesis.


METHODS
Nine volunteers were included to undergo intradermal injections of a total dose of 20~25 U BTA into one-half of the face, and normal saline into the other half as control. Clinical photographs were taken every 4 weeks for 16 weeks, and evaluated by a doctor blinded to the assignments. Patients graded the results of wrinkles elimination on each follow-up. Skin biopsies were taken before the treatment and 8 weeks after the injection. The specimens were assessed by a pathologist using hematoxylin and eosin stain, elastin stain, Masson trichrome stain and immunohistochemical stain with type I procollagen.


RESULTS
By photographic documentation, there was no significant face-lifting effect. However, there was statistical significance in wrinkles reduction on the BTA sides compared to pre-treatment. Subjectively, six subjects noticed better wrinkles soothing effect on the BTA sides. This effect was noted as early as 4 weeks after injection, and lasted for a minimum 8 weeks. The histologic examination revealed slight neocollagen synthesis by Masson trichrome stain on both sides.


CONCLUSIONS
Based on this pilot study, the face-lifting effect of intradermal injection with BTA was not conclusive. Interestingly, BTA showed moderate but significant wrinkles-soothing effect without obvious side effects on the lower face.
Chang
Shao-Ping
SP
Department of Dermatology, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan. joanna.ping@msa.hinet.net
Tsai
Hsiou-Hsin
HH
Chen
Wei-Yu
WY
Lee
Woan-Ruoh
WR
Chen
Ping-Ling
PL
Tsai
Tsung-Hsien
TH
D000328:Adult; D019274:Botulinum Toxins, Type A / Q000008:administration & dosage*; D003357:Cosmetic Techniques; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007271:Injections, Intradermal; D008297:Male; D008875:Middle Aged; D009465:Neuromuscular Agents / Q000008:administration & dosage*; D012867:Skin / Q000166:cytology / Q000187:drug effects; D015595:Skin Aging / Q000187:drug effects*
D009465:Neuromuscular Agents; D019274:Botulinum Toxins, Type A