Synergistic Effects of Intense Pulsed Light and Glycolic Acid on Photoaging and the Involvement of CD26 in Photoprotection.
Peihong Sun, Dongxin Shi, Ming Cheng et al.
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In 30 seconds
This prospective, randomized split-face study assessed combined intense pulsed light and glycolic acid (IAG) versus IPL alone in 20 people with photoaged skin, alongside mouse and fibroblast experiments examining CD26. On VISIA assessments, IAG significantly improved spots and red areas after one treatment (p < 0.001), while IPL required three treatments for similar results. In mice, IAG and IPL increased dermal thickness and Type I collagen. Cell experiments linked CD26 knockdown with greater DNA-damage and senescence markers and changes in signaling related to collagen synthesis and photoprotection.
Key findings
- IAG improved VISIA spot and red-area scores after one treatment (p < 0.001); IPL required three treatments for similar results.
- In the mouse model, dermal thickness and Type I collagen content increased after IAG and IPL treatment.
- CD26 knockdown in UVA-exposed fibroblasts increased γH2AX and β-galactosidase staining and reduced p-Smad and NRF2 levels.
Why it matters
The findings suggest that combining IPL with glycolic acid may produce earlier visible improvement than IPL alone, while experimental results implicate CD26 in pathways associated with collagen synthesis, DNA damage, and cellular senescence. The mechanistic observations provide a rationale for further study, but do not establish CD26 as a clinical target or demonstrate that its modulation improves patient outcomes.
What to keep in mind
The clinical cohort included only 20 participants, all with Fitzpatrick skin Type IV; the authors note that findings may not extend to other skin types and call for larger multi-ethnic studies.