Daily Cosmetic Research Analysis
Analyzed 18 papers and selected 3 impactful papers.
Summary
Mechanistic skin biology advances and pragmatic aesthetic safety data lead today's highlights. A PNAS study identifies PACC1 as the primary proton sensor that converts epidermal acidification into a desquamation signal. Clinically, combining ALA-PDT with surgery shows promising keloid control with mechanistic YAP/EN1 suppression, while a multicenter retrospective series suggests a favorable long-term safety profile for a novel PVA-based facial filler.
Research Themes
- Acid sensing and desquamation mechanisms in skin
- Keloid therapy optimization via PDT-surgery combination and YAP/EN1 modulation
- Long-term safety of novel facial filler materials (PVA composite)
Selected Articles
1. Proton-activated chloride channel PACC1 as acid sensor in epidermal desquamation.
This mechanistic study identifies PACC1 as the predominant proton sensor in keratinocytes, linking acidification to chloride efflux, JNK/AP-1 activation, KLK5/7 upregulation, and corneodesmosomal degradation. Genetic loss, pharmacologic inhibition, and rescue experiments converge to establish causality.
Impact: It pinpoints the core acid sensor that initiates epidermal desquamation, a foundational advance for barrier biology and targeted cosmetic/therapeutic modulation of exfoliation.
Clinical Implications: While preclinical, targeting PACC1-JNK/AP-1-KLK signaling could enable precise control of exfoliation and barrier repair in disorders of desquamation and in cosmetic formulations for controlled peeling.
Key Findings
- PACC1 is the predominant acid-sensitive ion channel in keratinocytes.
- Proton-activated PACC1 triggers chloride efflux and JNK/AP-1 signaling, upregulating KLK5/7.
- Acid-induced KLK upregulation is abolished by PACC1 knockdown/knockout, proton-sensing–deficient mutants, and pharmacologic inhibition.
- Functional reconstitution of PACC1 restores the acid response and desquamation signaling.
Methodological Strengths
- Convergent validation with genetic perturbation, pharmacology, and rescue reconstitution.
- Mechanistic linkage from ion flux to transcriptional program (JNK/AP-1) and protease output (KLK5/7).
Limitations
- Preclinical mechanistic work without clinical or in vivo human validation reported in the abstract.
- Specificity and safety of PACC1 modulation in intact skin require further study.
Future Directions: Develop selective PACC1 modulators; test efficacy and safety in skin disease models and human explants; delineate structural basis of proton sensing for drug design.
The acidic microenvironment of the stratum corneum is crucial for epidermal desquamation and barrier homeostasis, yet the primary proton sensor that triggers this process remains unknown. Here, we report that the proton-activated chloride channel PACC1 is essential for acid-induced upregulation of kallikreins (KLKs) and desmosomal degradation, two key steps in skin exfoliation. Functional and protein expression analyses revealed that PACC1 is the predominant acid-sensitive ion channel in keratinocytes. Proton-mediated PACC1 activation evokes chloride efflux and initiates a signaling cascade via the c-Jun N-terminal Kinase/AP-1 (JNK/AP-1) pathway. This cascade significantly enhances the expression and secretion of KLKs (KLK5/7), thereby facilitating desquamation through corneodesmosomal degradation. Notably, acid-induced KLK upregulation was abolished by PACC1 knockdown, knockout, or mutants that are deficient in proton sensing. This effect was also observed with pharmacological channel inhibition and was specifically restored by reconstitution with functional PACC1. These findings establish PACC1 as the core sensor that converts epidermal acidification into a desquamation signal, providing a mechanistic foundation for developing targeted therapeutic and cosmetic strategies that modulate skin barrier function.
2. Photodynamic Therapy Combined with Surgery: An Effective Treatment for Keloids via the YAP/Engrailed-1 Signaling Pathway.
Preoperative 20% ALA-PDT with a 0.5-cm margin, followed by excision at 24 hours and postoperative PDT, was associated with reduced YAP and Engrailed-1 expression and no keloid recurrence at ≥6 months. Results suggest a mechanistic role for YAP suppression and EN1 downregulation in clinical efficacy.
Impact: Introduces a biologically informed combination protocol for keloids with early outcome and mechanistic signals, addressing high recurrence rates in a cosmetically impactful condition.
Clinical Implications: PDT as an adjunct to excision may lower recurrence risk in keloids; standardized perioperative PDT could be considered in difficult cases, while acknowledging the need for controlled trials and pigmentation risk management.
Key Findings
- 20% ALA-PDT with a 0.5-cm preoperative margin, excision at 24 hours, and postoperative PDT formed the treatment protocol.
- Immunohistochemistry showed significant reductions in YAP and Engrailed-1 after PDT.
- No infections, scar exacerbations, or recurrences were observed over at least 6 months; postoperative hyperpigmentation occurred.
- Findings support a mechanistic link between YAP suppression, EN1 downregulation, and clinical response.
Methodological Strengths
- Integration of mechanistic biomarker assessment (IHC for YAP/EN1) with clinical outcomes.
- Protocolized perioperative PDT parameters enabling reproducibility.
Limitations
- Uncontrolled, small interventional case series with unspecified sample size.
- Short to intermediate follow-up (≥6 months); durability beyond this period is unknown.
Future Directions: Prospective controlled trials comparing surgery with vs. without perioperative PDT; longer follow-up; quantitative recurrence endpoints; assessment of pigmentary adverse events and patient-reported outcomes.
OBJECTIVE: Keloid, a unique human ailment, poses challenges in scar treatment due to variable efficacy and lengthy therapy and follow-up periods. Therefore, there is a need for a novel approach to address all forms of abnormal scarring. Photodynamic therapy (PDT), although slow-acting, shows promise, particularly when combined with surgery. This study aims to assess the efficacy and potential mechanism of PDT in conjunction with surgery for keloid treatment. METHODS: Keloid patients were identified through pathological examination, and the expression of YAP and Engrailed-1 in keloid tissue was determined via immunohistochemistry. Initially, all keloids underwent treatment with 20% ALA-PDT as the initial therapeutic step (the preoperative photodynamic therapy margin extends 0.5 cm beyond the visible lesion edge to ensure full target tissue coverage), using red LED light with specific parameters. Subsequently, keloids were surgically excised 24 hours post-PDT, followed by another PDT session. RESULTS: Immunohistochemistry assays revealed a significant reduction in YAP and Engrailed-1 levels in keloid tissues post-PDT. Over a minimum 6-month follow-up period, no infections, scar exacerbations, or recurrences were observed, except for postoperative hyperpigmentation. CONCLUSION: The combination of PDT and surgical therapy demonstrates promising results for keloid treatment. The suppression of YAP leading to reduced Engrailed-1 expression may represent a mechanism underlying the successful treatment of keloids with PDT.
3. A Retrospective Case Series Reporting the Safety of a Polyvinyl Alcohol (PVA) Composite Filler for Facial Augmentation.
In 279 patients (mean follow-up 24.5 months), a PVA composite filler was associated with a 1.07% rate of early, mild, self-resolving injection-site AEs and no late-onset complications. Descriptive efficacy in a small subset showed sustained improvement and high satisfaction.
Impact: Provides multicenter, longer-term real-world safety data for a novel filler class, informing risk counseling and product selection in aesthetic practice.
Clinical Implications: Suggests a low incidence of early mild AEs and no observed late-onset events up to roughly two years, supporting cautious adoption with ongoing surveillance; emphasizes need for prospective comparative data.
Key Findings
- Multicenter retrospective review of 279 patients with mean follow-up of 24.5 ± 7.2 months.
- Overall AE rate 1.07% (4 events in 3 patients), all early-onset, mild, and self-resolving injection-site reactions.
- No late-onset adverse events were documented.
- Descriptive efficacy (n=18) showed 72.2% GAIS improvement and high FACE-Q satisfaction.
Methodological Strengths
- Multicenter real-world dataset with extended follow-up.
- Systematic AE classification by onset, type, and severity.
Limitations
- Retrospective design with potential under-reporting and no comparator.
- Efficacy assessment limited to a small, selected subset (n=18) and descriptive only.
Future Directions: Prospective, controlled head-to-head studies versus established fillers; standardized outcome measures including ultrasound/histology; registry-based long-term surveillance for delayed granulomas or migration.
BACKGROUND: A novel polyvinyl alcohol (PVA)-based filler has been developed for durable facial augmentation. Despite its clinical application, long-term real-world data regarding its safety profile remain limited. OBJECTIVE: This study aimed to retrospectively assess the long-term safety profile and clinical outcomes of this PVA-based filler for facial augmentation. METHODS: A multi-center, retrospective case series was conducted across eight aesthetic clinics in China. Medical records of patients who received the PVA-based filler for facial augmentation between January 2022 and January 2025 with a follow-up of at least 18 months were reviewed. Adverse events (AEs) were extracted from the original medical charts and follow-up logs and were classified by time of onset, type, and severity. A post hoc descriptive efficacy assessment using the Global Aesthetic Improvement Scale (GAIS) and FACE-Q was performed on a sub-cohort with complete photographic documentation exceeding 12 months. RESULTS: A total of 279 patient charts were included, with a mean follow-up period of 24.5 ± 7.2 months. Three patients (1.07%) reported at least one AE (totaling 4 events), all of which were early-onset, transient, and mild injection site reactions that resolved spontaneously. No late-onset adverse events were reported in this cohort. The descriptive efficacy analysis (n = 18) demonstrated sustained corrective effects, with a 72.2% improvement rate on GAIS and high patient satisfaction scores on FACE-Q. CONCLUSION: In this retrospective cohort, the PVA-based composite filler demonstrated a low incidence of adverse events, with absence of documented late-onset complications in 279 patients. Descriptive observations of long-term efficacy are encouraging; further prospective, controlled studies are warranted to objectively substantiate its durability and performance.