Acne is a common chronic inflammatory disorder of the sebaceous gland in the hair follicle. Commonly used external medications cause skin irritation, and the transdermal capacity is weak, making it difficult to penetrate the cuticle skin barrier. Hair follicles can aid in the breakdown of this barrier. As nanomaterials progress, polymer-based nanocarriers are routinely used for hair follicle drug delivery to treat acne and other skin issues. Based on the physiological and anatomical characteristics of hair follicles, this paper discusses factors affecting hair follicle delivery by polymer nanocarriers, summarizes the common combination technology to improve the targeting of hair follicles by carriers, and finally reviews the most recent research progress of different polymer nanodrug-delivery systems for the treatment of acne by targeting hair follicles.

BACKGROUND: Prior research has explored the relationship between inflammatory skin disorders and breast cancer (BC), yet the causality of this association remains uncertain.
METHODS: Utilizing a bidirectional two-sample Mendelian randomization (MR) approach, this study aimed to elucidate the causal dynamics between various inflammatory skin conditions-namely acne, atopic dermatitis, psoriasis vulgaris, urticaria, and rosacea-and BC. Genetic variants implicated in these disorders were sourced from comprehensive genome-wide association studies representative of European ancestry. In the forward MR, BC was posited as the exposure, while the reverse MR treated each inflammatory skin disease as the exposure. A suite of analytical methodologies, including random effects inverse variance weighted (IVW), weighted median (WME), and MR-Egger, were employed to probe the causative links between inflammatory skin diseases and BC. Sensitivity analyses, alongside evaluations for heterogeneity and pleiotropy, were conducted to substantiate the findings.
RESULTS: The MR analysis revealed an increased risk of acne associated with BC (IVW: OR = 1.063, 95% CI = 1.011-1.117, p = 0.016), while noting a decreased risk of atopic dermatitis (AD) in BC patients (IVW: OR = 0.941, 95% CI = 0.886-0.999, p = 0.047). No significant associations were observed between BC and psoriasis vulgaris, urticaria, or rosacea. Conversely, reverse MR analyses detected no effect of BC on the incidence of inflammatory skin diseases. The absence of pleiotropy and the consistency of these outcomes strengthen the study\'s conclusions.
CONCLUSIONS: Findings indicate an elevated incidence of acne and a reduced incidence of AD in individuals with BC within the European population.

Cutibacterium acnes is the most abundant bacterium of the human skin microbiome since adolescence, participating in both skin homeostasis and diseases. Here, we demonstrate individual and niche heterogeneity of C. acnes from 1,234 isolate genomes. Skin disease (atopic dermatitis and acne) and body site shape genomic differences of C. acnes, stemming from horizontal gene transfer and selection pressure. C. acnes harbors characteristic metabolic functions, fewer antibiotic resistance genes and virulence factors, and a more stable genome compared with Staphylococcus epidermidis. Integrated genome, transcriptome, and metabolome analysis at the strain level unveils the functional characteristics of C. acnes. Consistent with the transcriptome signature, C. acnes in a sebum-rich environment induces toxic and pro-inflammatory effects on keratinocytes. L-carnosine, an anti-oxidative stress metabolite, is up-regulated in the C. acnes metabolome from atopic dermatitis and attenuates skin inflammation. Collectively, our study reveals the joint impact of genes and the microenvironment on C. acnes function.

UNASSIGNED: Acne vulgaris, a chronic inflammatory skin condition predominantly seen in teenagers, impacts more than 640 million people worldwide. The potential use of lipid-lowering medications as a treatment for acne vulgaris remains underexplored. This study seeks to investigate the impact of lipid-lowering therapies on the risk of developing acne vulgaris using two-sample Mendelian randomization (MR) analysis.
UNASSIGNED: The two-sample MR method was employed for analysis, and information on lipid-lowering drugs was obtained from the DrugBank and ChEMBL databases. The summary data for blood low-density lipoprotein (LDL) and triglycerides were sourced from the Global Lipids Genetics Consortium, while genome-wide association studies (GWAS) summary data for acne vulgaris were obtained from the FinnGen database. Heterogeneity was examined using the Q-test, horizontal pleiotropy was assessed using MR-Presso, and the robustness of analysis results was evaluated using leave-one-out analysis.
UNASSIGNED: The MR analysis provided robust evidence for an association between lowering LDL cholesterol through two drug targets and acne vulgaris, with PCSK9 showing an odds ratio (OR) of 1.782 (95%CI: 1.129-2.812, p = 0.013) and LDL receptor (LDLR) with an OR of 1.581 (95%CI: 1.071-2.334, p = 0.021). Similarly, targeting the lowering of triglycerides through lipoprotein lipase (LPL) was significantly associated with an increased risk of acne vulgaris, indicated by an OR of 1.607 (95%CI: 1.124-2.299, p = 0.009).
UNASSIGNED: The current MR study presented suggestive evidence of a positive association between drugs targeting three genes (PCSK9, LDLR, and LPL) to lower lipids and a reduced risk of acne vulgaris.

OBJECTIVE: To investigate ocular surface disorders and tear function changes in patients with acne vulgaris and explore the potential relationship between acne vulgaris and dry eye.
METHODS: This cross-sectional study included right eyes of 53 patients with acne vulgaris and 54 healthy controls. The participants completed the Ocular Surface Disease Index (OSDI) questionnaire. The following ocular surface-related parameters were measured: tear meniscus height (TMH), noninvasive tear breakup time (NIBUT), Schirmer I test (SIT), lipid layer thickness (LLT) score of the tear film, meibum score, meibomian gland orifice obstruction score, the ratio of meibomian gland loss, conjunctival hyperemia score, and corneal fluorescein staining (CFS) score.
RESULTS: The stability of the tear film decreased in acne vulgaris patients. In the acne group, the TMH and NIBUT were lower, whereas the OSDI, meibum score, meibomian gland orifice obstruction score, ratio of meibomian gland loss, and conjunctival hyperemia score were higher compared with controls (P<0.05). There were no significant differences in the CFS score, SIT, or LLT score between the groups (P>0.05). In two dry eye groups, the TMH, NIBUT, and LLT score were lower in the acne with dry eye (acne-DE) group, and the meibum score, meibomian gland orifice obstruction score, ratio of meibomian gland loss and conjunctival hyperemia score in the acne-DE group were higher (P<0.05). There were no significant differences between OSDI, SIT, and CFS score (P>0.05).
CONCLUSIONS: Patients with moderate-to-severe acne vulgaris are more likely to experience dry eye than those without acne vulgaris. Reduced tear film stability and meibomian gland structure dysfunction are more pronounced in patients with moderate-to-severe acne and dry eye.

UNASSIGNED: Acne vulgaris is a chronic inflammatory skin disorder centered on hair follicles, making hair follicle-targeted delivery of anti-acne drugs a promising option for acne treatment. However, current researches have only focused on the delivering to healthy hair follicles, which are intrinsically different from pathologically clogged hair follicles in acne vulgaris.
UNASSIGNED: Azelaic acid (AZA) micro/nanocrystals with different particle sizes were prepared by wet media milling or high-pressure homogenization. An experiment on AZA micro/nanocrystals delivering to healthy hair follicles was carried out, with and without the use of physical enhancement techniques. More importantly, it innovatively designed an experiment, which could reveal the ability of AZA micro/nanocrystals to penetrate the constructed clogged hair follicles. The anti-inflammatory and antibacterial effects of AZA micro/nanocrystals were evaluated in vitro using a RAW264.7 cell model stimulated by lipopolysaccharide and a Cutibacterium acnes model. Finally, both the anti-acne effects and skin safety of AZA micro/nanocrystals and commercial products were compared in vivo.
UNASSIGNED: In comparison to commercial products, 200 nm and 500 nm AZA micro/nanocrystals exhibited an increased capacity to target hair follicles. In the combination group of AZA micro/nanocrystals and ultrasound, the ability to penetrate hair follicles was further remarkably enhanced (ER value up to 9.6). However, toward the clogged hair follicles, AZA micro/nanocrystals cannot easily penetrate into by themselves. Only with the help of 1% salicylic acid, AZA micro/nanocrystals had a great potential to penetrate clogged hair follicle. It was also shown that AZA micro/nanocrystals had anti-inflammatory and antibacterial effects by inhibiting pro-inflammatory factors and Cutibacterium acnes. Compared with commercial products, the combination of AZA micro/nanocrystals and ultrasound exhibited an obvious advantage in both skin safety and in vivo anti-acne therapeutic efficacy.
UNASSIGNED: Hair follicle-targeted delivery of AZA micro/nanocrystals provided a satisfactory alternative in promoting the treatment of acne vulgaris.

BACKGROUND: Acne vulgaris is a species-specific human disease. To date, there has been no established human sebocyte cell line of Asian origin. Our previous study has demonstrated the efficacy of 5-aminolevulinic acid photodynamic therapy (ALA-PDT) in the treatment of acne vulgaris, primarily attributed to its cytotoxic properties; however, its regulatory mechanism remains largely unknown.
OBJECTIVE: To establish an immortalized human sebocyte cell line derived from Chinese population and investigate the underlying mechanism of ALA-PDT.
METHODS: Human primary sebocytes were transfected with the human tert gene (h‑tert). The biological characteristics, including cell proliferation, cell markers, and sebum secretion function, were compared between primary sebocytes and the immortalized sebocytes (XL-i-20). Stimulations such as ALA-PDT, were applied respectively to both primary sebocytes and XL-i-20 cells to assess changes in their cellular functions. The transcriptome differences between primary sebocytes and XL-i-20 sebocytes were investigated using RNA-seq analysis. The XL-i-20 cell line was used to establish a sebaceous gland (SG) organoid culture, serving as a representative model of SG for the investigation of ALA-PDT.
RESULTS: The h‑tert immortalized sebocyte cell line exhibited the ability to be consecutively cultured for more than fifty passages. Both primary and immortalized cells expressed sebocyte markers such as epithelial membrane antigens (EMA, or MUC-1), Cytokeratin 7 (CK7) and adipose differentiation-related protein associated antigens (ADRP), and maintained sebum secretion function. The proliferative capacity of XL-i-20 was found to be significantly higher than that of primary sebocytes. The responses of XL-i-20 to ALA-PDT were indistinguishable from those elicited by primary sebocytes. Cell viability and sebum secretion were decreased after ALA-PDT in both two cell lines, and lipid-related proteins (SREBP-1/PPARγ) were down-regulated. The transcriptome data consistently demonstrated upregulation of genes related to inflammatory responses and downregulation of genes involved in lipid metabolism in both cell types following PDT. The analysis of common differential genes of primary sebocytes and XL-i-20 sebocytes post ALA-PDT showed that TNF signaling pathways, MAPK signaling pathways and JAK-STAT signaling pathways were activated. The SG organoids were spherical, which expressed markers of FANS and PLET1. Ki-67 was down-regulated after ALA-PDT.
CONCLUSIONS: We have developed an h‑tert immortalized sebocyte cell line from an Asian population. The cell line, XL-i-20, maintains the essential characteristics of its parent primary sebocytes. Moreover, XL-i-20 sebocyte exhibited a significant respond to ALA-PDT, demonstrating comparable phenotypic and molecular changes to primary sebocytes. Therefore, XL-i-20 and its derived SG organoid serve as appropriate in vitro models for investigating the efficacy and mechanisms of ALA-PDT in SG-related diseases.

OBJECTIVE: A 6-month interval between systemic isotretinoin (ISO) and the initiation of energy-based interventions has been recommended, due to concerns about keloid formation and delayed wound healing. While this postponement goes against the current trend of early intervention for acne scarring. This systematic review evaluates the efficacy, safety, and patient satisfaction of combinations of ISO with energy-based devices (EBD).
UNASSIGNED: PubMed, Embase, Web of Science, Cochrane Library, and Cochrane Central Register of Controlled Trials were comprehensively searched up to April 2023 according to PRISMA guidelines. Two independent reviewers screened the titles and abstracts to select articles. The quality of the literature was assessed for each study design.
RESULTS: A total of 16 studies addressing the efficacy and safety of energy-based modalities combined with ISO were identified, including six randomized controlled trials (RCTs), two case series, seven cohort studies, and one case report. ISO combinations with intense pulsed light (IPL), fractional ablative CO2 laser, pulsed dye laser (PDL), non-ablative fractional laser (NAFL) and fractional microneedle radiofrequency (FMRF) have been tested for improving acne severity, acne scarring and erythema.
CONCLUSIONS: The current evidence does not justify delaying the use of EBDs for patients who have recently undergone or are currently receiving ISO treatment. Evidence-based treatments such as PDL, NAFL, and FMRF etc. are suggested relatively safe and effective in treating acne and acne scarring.

Glycyrrhizae Radix et rhizome/licorice is a precious herb in traditional Chinese medicine (TCM). TCM\'s polysaccharides are medicinally active. But herbal polysaccharides pose some limitations for topical applications. Therefore, this study aimed to utilize licorice polysaccharide via mesoporous silica nanoparticles (MSN) for anti-acne efficacy in topical delivery. The polysaccharide (GGP) was extracted with a 10 % NaOH solution. Chemical characterization suggested that GGP possesses an Mw of 267.9 kDa, comprised primarily of Glc (54.1 %) and Ara (19.12 %), and probably 1,4-linked Glc as a backbone. Then, MSN and amino-functionalized MSN were synthesized, GGP entrapped, and coated with polydopamine (PDA) to produce nanoparticle cargo. The resulted product exhibited 76 % entrapment efficiency and an in vitro release of 89 % at pH 5, which is usually an acne-prone skin\'s pH. Moreover, it significantly increased Sebocytes\' cellular uptake. GGP effectively acted as an anti-acne agent and preserved its efficacy in synthesized nanoparticles. In vivo, the results showed that a 20 % gel of MSN-NH2-GGP@PDA could mediate an inflammatory response via inhibiting pro-inflammatory cytokines and regulating anti-inflammatory cytokines. The MSN-NH2-GGP@PDA inhibited TLR2-activated-MAPK and NF-κB pathway triggered by heat-killed P. acnes. In conclusion, fabricated MSN entrapped GGP for biomimetic anti-acne efficacy in topical application.

Glycyrrhetinic acid (GA) is a saponin compound, isolated from licorice (Glycyrrhiza glabra), which has been wildly explored for its intriguing pharmacological and medicinal effects. GA is a triterpenoid glycoside displaying an array of pharmacological and biological activities, including anti-inflammatory, anti-bacterial, antiviral and antioxidative properties. In this study, we investigated the underlying mechanisms of GA on acne vulgaris through network pharmacology and proteomics. After the intersection of the 154 drug targets and 581 disease targets, 37 therapeutic targets for GA against acne were obtained. A protein-protein interaction (PPI) network analysis highlighted TNF, IL1B, IL6, ESR1, PPARG, NFKB1, STAT3 and TLR4 as key targets of GA against acne, which is further verified by molecular docking. The experimental results showed that GA inhibited lipid synthesis in vitro and in vivo, improved the histopathological damage of skin, prevented mast cell infiltration and decreased the level of pro-inflammatory cytokines, including TNF-α, IL-1β and IL-6. This study indicates that GA may regulate multiple pathways to improve acne symptoms, and the beneficial effects of GA against acne vulgaris might be through the regulation of sebogenesis and inflammatory responses.