賀!生髮新研究發表:以Fraxel飛梭雷射強化毛囊再生之研究論文

 

台大皮膚科與台大醫學工程研究所林頌然教授團隊新發表的研究題目:
以非剝離式飛梭雷射(即台灣俗稱的Fraxel二代飛梭雷射)強化毛囊再生功能
獲刊登於Lasers in Surgery and Medicine期刊。

王修含醫師有幸參與此研究,特將此論文摘要附錄於下:

 

 

Lasers Surg Med. 2015 Apr;47(4):331-41. doi: 10.1002/lsm.22330. Epub 2015 Apr 10.
 

Enhancing hair follicle regeneration by nonablative fractional laser: Assessment of irradiation parameters and tissue response.

 
 
Authors: Yueh‐Feng Wu, Shiou‐Han Wang, Pei‐Shan Wu, Sabrina Mai‐Yi Fan, Hsien‐Yi Chiu, Tsung‐Hua Tsai, Sung‐Jan Lin
作者:吳岳峰, 王修含, 吳佩珊, 范邁儀, 邱顯鎰, 蔡宗樺, 林頌然
 
 

Background and Objective

Identification of methods to enhance anagen entry can be helpful for alopecia. Recently, nonablative laser has been proposed as a potential treatment for alopecia. However, how the laser parameters affect stem cell activity, hair cycles and the associated side effects have not been well characterized. Here we examine the effects of irradiation parameters of 1,550-nm fractional laser on hair cycles.

Study Design/Materials and Methods

The dorsal skin of eight-week-old female C57BL/6 mice with hair follicles in synchronized telogen was shaved and irradiated with a 1,550-nm fractional erbium-glass laser (Fraxel RE:STORE (SR1500) Laser System, Solta Medical, U.S.A.) with varied beam energies (5–35 mJ) and beam densities (500–3500 microthermal zones/cm2). The cutaneous changes were evaluated both grossly and histologically. Hair follicle stem cell activity was detected by BrdU incorporation and changes in gene expression were quantified by real-time PCR.

Results

Direct thermal injury to hair follicles could be observed early after irradiation, especially at higher beam energy. Anagen induction in the irradiated skin showed an all-or-non change. Anagen induction and ulcer formation were affected by the combination of beam energy and density. The lowest beam energy of 5 mJ failed to promote anagen entry at all beam densities tested. As beam energy increased from 10 mJ to 35 mJ, we found a decreasing trend of beam density that could induce anagen entry within 7–9 days with activation of hair follicle stem cells. Beam density above the pro-regeneration density could lead to ulcers and scarring followed by anagen entry in adjacent skin. Analysis of inflammatory cytokines, including TNF-α, IL-1β, and IL-6, revealed that transient moderate inflammation was associated with anagen induction and intense prolonged inflammation preceded ulcer formation.

 
Fig. 1. Laser irradiation. A. The skin on sides of the trunk was firmly stretched and irradiated with
a 1,550nm fractional erbium-glass laser. B. The red rectangle indicated the irradiated area. C.
Schematic diagram of the post-natal synchronized hair cycles on the back of C57BL/6 mice. The
second telogen started at week 7 and persisted for about 5 weeks. Laser irradiation was performed
on week 8. M: morphogenesis; C: catagen; T: telogen; A: anagen.

 
Fig. 2. Laser beam energy and MTZ. Irradiated skin was sampled 1 day after irradiation. A.
Histology. MTZ could be identified by denatured collagen that showed a homogenized bluish
change. H&E staining. Bar¼100 mm. B. There was an increasing trend of the depth of MTZ as
beam energy was elevated. *P<0.05 compared with 5mJ group (N¼5). C. There was an
increasing trend of the width of MTZ as beam energy was elevated. *P<0.05 compared with 5mJ
group (N¼5).

 
Fig. 3. The effect of laser irradiation parameters on anagen induction and ulcer formation. A. Laser
beam energy was increased from 5 to 35mJ and laser beam density was increased from 500 to
3500MTZ/cm2. Yellow color indicated the therapeutic window in which premature anagen was
induced without ulcer formation. B. Quantification of the dynamics of anagen entry at various
irradiation parameters. P<0.05 compared with day 0 (N=5) in each group. 80103mm.
 

 
Fig. 4. Changes of skin and hair cycles. Laser beam energy was 15 mJ. At beam density of 552 MTZ/
cm2, no premature anagen entry was induced. At beam density of 1048MTZ/cm2, irradiated skin
started to turn grayish on day 9 to day 11(blue arrow head), indicating initiation of anagen. No skin
erosion or ulcer was observed. At beam density of 1600MTZ/cm2 and 2010MTZ/cm2, an ulcer
developed in the center of irradiated skin on day 5 and day 7 respectively (red arrow head).
Premature anagen entry surrounding the scar tissue was observed (yellow arrow head).

 
Fig. 5. Histological changes during hair cycle progression. Beam energy was 15mJ and beam
density was 1048MTZ/cm2. A. Comparison of gross skin change and histology. H&E staining.
Bar?100mm. B. Quantification of anagen entry area. * P<0.05 compared with day 0 (N=5). C.
Quantification of hair follicle length. * P<0.05 compared with day 0 (N=5).


 
Fig. 6(A). Dynamic changes of cell proliferation in hair follicles. Beam energy was 15mJ and beam
density was 1048MTZ/cm2. A. Double staining for BrdU and p-cadherin.
 
 
Fig. 6(B). Dynamic changes of cell proliferation in hair follicles. Beam energy was 15mJ and beam
density was 1048MTZ/cm2. A. Double staining for BrdU and p-cadherin. B. Double staining for
BrdU and K15. Secondary hair germ was positive for p-cadherin and HFSC was identified by K15.
From day 1 to day 5, BrdU was positive above bulge (yellow arrow heads). On day 7, BrdU was
positive in secondary hair germ to lower bulge (white arrow heads). On day 9 and day 11, BrdU was positive in bulge (red arrow heads). Many BrdU positive cells could be found in the hair matrix on day 9 to day 13 (green arrow heads). DP: dermal papilla; SG: secondary hair germ; BG: bulge.
Bar=50mm.
 
Fig. 7. Expression of IL-6 (A), TNF-a (B), and IL-1b (C) after laser
irradiation of varied beam densities. Laser beam energy was
15 mJ. At beam density of 552 MTZ/cm2, very slight increase of IL-
6, TNF-a, and IL-1b was detected after irradiation. At beam
density of 1048MTZ/cm2, a moderate increase of IL-6, TNF-a, and
IL-1b was observed from day 1 to day 3. At beam density of
1600MTZ/cm2, prolonged and higher levels of IL-6, TNF-a, and
IL-1b were observed.
 

Conclusion

To avoid side effects of hair follicle injury and scarring, appropriate combination of beam energy and density is required. Parameters outside the therapeutic window can result in either no anagen promotion or ulcer formation.

Keywords:

  • alopecia;
  • 1,550-nm erbium glass laser;
  • hair follicle regeneration;
  • stem cell;
  • inflammation


Lasers Surg. Med. 47:331–341, 2015. © 2015 Wiley Periodicals, Inc.

 

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