LACTIC ACID

A choline-oxalic acid deep eutectic solvent (DES) was developed for the molecular-weight-controlled extraction of collagen peptides from sturgeon ( Acipenser spp.) skin, a collagen-rich fish-processing by-product containing 78.28% protein and 63.47% collagen. Among three choline-based organic-acid DESs, choline-oxalic acid exhibited the best extraction performance and produced lower-molecular-weight peptide fractions than choline-lactic acid and choline-acetic acid systems. Under the optimized conditions of 70 °C, a solid-to-liquid ratio of 1:80, and 2 h, the extraction rate reached 98.45%. Time-dependent extraction enabled controllable peptide production: a 2 h treatment mainly generated collagen polypeptides in the 1-10 kDa range, whereas extending the reaction to 4 h produced oligopeptides predominantly in the 0.5-1 kDa range. For downstream recovery, isopropanol showed the highest precipitation efficiency, achieving approximately 92% peptide recovery at an extract-to-solvent ratio of 1:6. UV-Vis analysis showed a characteristic collagen peptide absorption band near 230 nm, while FT-IR spectra displayed typical amide bands, including amide I at approximately 1630 cm -1 and amide III at 1240-1300 cm -1 , confirming the collagen-derived nature of the products. Molecular simulation further suggested that oxalic acid competed for backbone hydrogen bonding, while chloride ions interacted with hydroxyproline residues, as indicated by a Hyp-Cl - radial distribution peak at 0.328 nm, promoting collagen swelling, triple-helix loosening, and controlled depolymerization. Overall, this DES-based strategy provides a rapid, tunable, and potentially sustainable route for producing collagen peptides from aquatic by-products.

Poly-L-lactic acid (PLLA) is a well-established facial filler recognized for its ability to stimulate collagen synthesis. While emerging evidence suggests that PLLA modulates the differentiation and lipolysis of dermal adipocytes, its role in autologous fat transplantation remains unclear. In vitro, mature adipocytes were treated with lactate or PLLA during ceiling culture to explore the regulatory mechanisms of PLLA-mediated dedifferentiation. Subsequently, we established a murine model of PLLA and adipose tissue co-transplantation, with grafts harvested at 7, 30, and 90 days. Graft survival was assessed via volumetric analysis, histological evaluation, and qPCR to validate the in vitro findings. PLLA-derived lactate facilitates adipocyte dedifferentiation at low-to-moderate concentrations. This phenotypic reversion was abrogated by pharmacological inhibition of monocarboxylate transporters (MCTs). Additionally, lactate-induced DFATs exhibited enhanced angiogenic potential. In vivo, co-transplantation of PLLA and adipose tissue significantly enhanced volume retention and neovascularization. PLLA implantation triggered only a transient acute inflammatory response that stabilized subsequently without inducing chronic fibrosis, ensuring long-term biocompatibility. As a biocompatible synthetic material, PLLA degrades into lactate and enhances fat graft volume retention by promoting dedifferentiation of adipocytes. This finding indicates that PLLA holds broad application prospects in fat transplantation. This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable.

Skin contact is an important route for human exposure to atmospheric pollutants. Many atmospheric pollutants possess photochemical activity, and skin sweat provides a natural environment for the photogeneration of reactive species (RSs) from pollutants. However, the photochemical transformation of atmospheric pollutants in skin sweat and their toxicological effects on the skin remain poorly understood. Herein, 1-nitronaphthalene (1-NN), a common atmospheric pollutant, was used as a model compound to investigate the influence of key components (i.e., Organic acids, Fe 3 + ) of skin sweat on the degradation and transformation mechanisms of 1-NN, as well as the skin toxicity of its transformation products. Our results show that lactic acid (LA) facilitated the photodegradation of 1-NN. The excited triplet state 1-NN ( 3 1-NN*) can oxidize LA to generate carbon-centered radicals (·CH(CH 3 )OH) that was confirmed by EPR spin trapping and high-resolution mass spectrometry. Histidine (His) further accelerates this process by consuming dissolved oxygen ( 3 O 2 ), thereby inhibiting the quenching of 3 1-NN* as well as carbon-centered radicals by 3 O 2 . Additionally, the presence of Fe 3+ can trigger the generation of carboxyl radicals (CO 2 •- ) via carboxylic acid ligand-to-metal charge transfer, further enhancing the photodegradation of 1-NN. Toxicity assays indicated that the photochemical transformation process of 1-NN can lead to higher cytotoxicity. These findings provide a new strategy for understanding the transformation processes and toxicity evolution of nitrated polycyclic aromatic hydrocarbons on the skin surface.

Dermal senescence is associated with reduced fibroblast activity, decreased extracellular matrix synthesis, and impaired tissue repair. Commercial injectable formulations containing poly-L-lactic acid (PLLA), hyaluronic acid (HA), and polydeoxyribonucleotide (PDRN)-associated compounds have been proposed for dermal remodeling approaches and modulate tissue-response pathways; however, comparative studies evaluating commercially available formulations under standardized experimental conditions remain limited. This study aimed to characterize the morphology of formulations containing PLLA, HA, and PDRN, used alone or in combination, by environmental scanning electron microscopy (ESEM), and to investigate formulation-associated histological and collagen-related molecular responses in a murine model. Formulations containing PLLA, HA, HA + PDRN, and PLLA, HA and PDRN were administered into the dorsal subcutaneous tissue of 14 Mus musculus mice (Swiss strain). After 30 days, tissue response was assessed by ultrasound, histological analysis with Masson's trichrome staining, and RT-qPCR quantification of collagen-related gene expression. ESEM analysis revealed distinct morphological characteristics among the biomaterials, and the combined PLLA, HA and PDRN formulation exhibited a more complex and integrated multiphase structure. Histological analysis showed preserved tissue architecture in all groups, with no evidence of marked inflammatory response or structural disruption. RT-qPCR demonstrated significantly higher COL1A1 expression in the PLLA-only and PLLA, HA, and PDRN groups compared with controls ( p < 0.05), whereas no significant differences were observed for COL2A1 or COL3A1. These findings indicate that PLLA-containing formulations were associated with selective COL1A1 upregulation under the evaluated conditions, suggesting formulation-associated collagen-related molecular responses in this short-term model.

Aesthetic patients are increasingly aware of the contrast between rejuvenated facial skin and untreated aging skin of the décolletage, and frequently request cosmetic enhancement of this area. Poly-L-lactic acid (Sculptra®, Galderma; PLLA-SCA) is a regenerative biostimulator that stimulates collagen and elastin production to help regenerate the skin’s inner structure. This 9-month, open-label study investigated the effectiveness and safety of correcting décolletage wrinkles with PLLA-SCA using 2 reconstitution volumes. Women with moderate/severe wrinkles on the Galderma Décolletage Scale (GDS) were randomized 1:1 to receive PLLA-SCA reconstituted with 8 mL or 17 mL sterile water for injection, plus 1 mL 2% lidocaine (up to 4 treatments, 1 month apart). Assessments included GDS, Global Aesthetic Improvement Scale (GAIS), subject satisfaction, skin quality, and adverse events (AEs). Of 30 randomized subjects, the majority (8 mL: 93.8%; 17 mL: 78.6%) showed a ≥1-point improvement on investigator-assessed GDS at month 9 (primary endpoint), with ≥93% improved also at month 6. GAIS improvement was also great (>90% of subjects) across both groups at months 6 and 9. In both groups, >90% of subjects reported satisfaction with the appearance of their wrinkles by month 3, and this satisfaction was sustained throughout the study. The majority (>80%) of subjects were satisfied with the texture, smoothness, and radiance of their skin at months 6 and 9. One AE was judged as treatment-related; no AEs were serious or led to discontinuation. Treatment of the décolletage area with PLLA-SCA was effective and well tolerated with both reconstitution volumes, with high subject satisfaction.

Glucagon-like peptide-1 (GLP-1) receptor agonists (RAs) used for weight management have introduced unintended facial changes only partially addressed by conventional volumizing fillers. Evaluate the mechanistic rationale and clinical evidence supporting poly-l-lactic acid Sculptra (PLLA-SCA) as a biostimulatory and regenerative treatment for GLP-1 RA-associated facial changes. This narrative review synthesizes mechanistic and clinical data alongside expert opinion regarding PLLA-SCA for GLP-1 RA-driven weight loss, focusing on its biostimulatory and regenerative effects across skin layers. Poly-l-lactic acid Sculptra induces fibroblast recruitment and stimulates regeneration of collagen and elastin, and effects vasculature and adipose tissue, resulting in durable improvements in skin quality, elasticity, facial contour, and perceived age that persist for 2 years or longer. Clinical studies and real-world experiences demonstrate clinically meaningful corrections of midface and perioral volume loss, jawline contour, and radiance, including in patients with GLP-1 RA-related facial changes. Poly-l-lactic acid Sculptra may help address GLP-1 RA-associated facial atrophy by supporting long-term regeneration and restoration of facial definition, contour, and skin quality. The effects potentially extend across all 3 skin layers affected by the GLP-1 RA phenotype, including atrophy and gauntness. Poly-L-lactic acid Sculptra offers clinicians an option to deliver durable regenerative treatment that helps restore facial aesthetics in this patient population.

Treatment modalities for rotator cuff tears are continuously evolving. Augmentation of rotator cuff repair with biocomposite implants with bioinductive properties such as collagen scaffolds, dermal grafts, and synthetic materials are increasingly being used to ensure repair integrity. Ideally, an implant should provide added structural integrity as well as biologic components that augment the final repair tissue quality. A 69-year-old male underwent arthroscopic rotator cuff repair augmented with a BioBrace Reinforced BioInductive Implant (CONMED Corporation), a biocomposite implant containing type 1 bovine collagen with poly-L-lactic acid. With physical therapy, the patient's periscapular and rotator cuff strengthening had progressed by 8 weeks postoperatively, and full return to activities began at 6 months postoperatively. Postoperative magnetic resonance imaging at 1 year demonstrated complete healing of the rotator cuff repair with intact footprint on coronal and sagittal images. This biocomposite implant provides an encouraging option for use in patients with poor tissue quality or tear patterns that are concerning for possible postoperative retear.

Thread lifting has emerged as a minimally invasive alternative to surgical facial rejuvenation, providing mechanical tissue repositioning with shorter recovery times. Advances in biomaterials and thread design have improved safety and lifting capacity; however, variability in clinical outcomes persists due to differences in vector design, thread type, tissue manipulation, and anesthesia techniques. These factors may influence complication rates, procedural tolerance, and postoperative downtime, contributing to ongoing concerns regarding the predictability and reproducibility of thread-lifting procedures. To describe the development of a vector-optimized thread-lifting technique (VectorLift) and to compare its clinical performance in an exploratory, real-world, non-randomized comparative study with two commonly used thread-lifting approaches employing different biomaterials and insertion methods. The VectorLift protocol was developed using anatomically guided vector placement, ligament-oriented reinforcement, and optimized local anesthetic infiltration. Over a three-year period, 44 female patients (mean age 47 years) underwent facial thread-lifting procedures. Eighteen patients were treated using the proposed technique with cannulated polydioxanone (PDO) threads, while the remaining patients were treated with either double-needle poly-L-lactic acid (PLA) plus poly(L-lactide-co-glycolide) (PLGA) cone threads or cannulated PLA/polycaprolactone (PCL) threads. Clinical outcomes included recovery time (days of downtime), intraoperative pain levels, patient satisfaction measured using the FACE-Q scale before treatment and two weeks post-procedure, and complication rates including dimpling, bruising, edema, and transient asymmetry. Standardized clinical photographs were obtained before and immediately after treatment. VectorLift was associated with lower reported intraoperative pain, shorter recovery time and lower rates of early postoperative complications compared with the other techniques, while patient satisfaction scores were comparable among groups. Immediate photographic assessment confirmed visible aesthetic improvement without overcorrection. VectorLift is an anatomically guided thread-lifting technique that, in this real-world non-randomized comparative study, was associated with improved procedural tolerance and shorter postoperative downtime while maintaining high patient satisfaction and effective aesthetic outcomes. Further controlled studies with larger patient populations and longer follow-up periods are warranted to confirm these findings.

The prevailing paradigm in aesthetic medicine is the "antiaging" model, which focuses on correcting and/or reversing visible signs of aging. However, contemporary geroscience reconceptualizes aging as a malleable biological process driven by defined hallmarks, offering an opportunity to align aesthetic practice with the fundamental aging biology. This article explores the concept of "pro-aging" or "longevity aesthetics," a framework that prioritizes tissue function, resilience, and biological integrity alongside phenotypic improvement. The skin is presented as an accessible model organ that reflects key hallmarks of aging and their clinical manifestations. Although conventional aesthetic interventions effectively address structural changes, they often do not target upstream biological drivers of tissue aging. Within this framework, certain surgical and nonsurgical modalities may theoretically support tissue resilience through modulation of inflammation, collagen remodeling, and microvascular health. Importantly, some of these strategies, such as biostimulatory injectables including calcium hydroxylapatite and poly-L-lactic acid, as well as combination treatment approaches, are already integrated into clinical practice, whereas others remain in the translational or research domain. Emerging concepts such as multi-omics, defined as the integration of genomics, transcriptomics, proteomics, metabolomics, and epigenomics, may further enable personalized and predictive approaches in the future. Longevity aesthetics, therefore, represents a conceptual evolution from correction to functional preservation. However, direct clinical evidence supporting its biological impact remains limited, and these concepts should currently be interpreted as hypothesis driven. Advancing this framework will require prospective studies integrating biomarkers with long-term clinical outcomes. Ultimately, this approach positions aesthetic medicine to contribute to translational geroscience, provided innovation is guided by methodological rigor and ethical transparency. Level of Evidence: 5 (Therapeutic).

Biostimulatory fillers, such as poly-L-lactic acid (PLLA), poly-D,L-lactic acid (PDLLA), polycaprolactone (PCL), and calcium hydroxyapatite (CaHA), have transformed aesthetics by promoting neocollagenesis through regulated inflammatory and cytokine-driven cascades. Their clinical effectiveness is well-established, but there is a lack of a synthesis of their mechanisms of action. The proposed comprehensive narrative literature review synthesized the contemporary evidence on the cytokine-modulating mechanisms and pathways of inflammatory responses induced by PLLA, PDLLA, PCL, and CaHA. The study design is a narrative literature review, which is performed using a systematic approach based on PRISMA 2020 guidelines. As a comprehensive literature review incorporating heterogeneous and predominantly non-comparative study designs, a formal risk-of-bias assessment using standardized tools was not performed; however, study limitations were considered qualitatively. It matched the identified mechanistic processes with clinical outcomes and safety profiles. The review included 22 clinical studies published from 1stJanuary 2010 to 28th February 2026, comprising randomized controlled trials, cohort studies, and quasi-experimental designs. Extracted data were systematically categorized into six predefined domains: acute inflammatory profile, macrophage polarization, fibroblast extracellular matrix (ECM) response, angiogenesis, clinical outcomes, and adverse events based on thematic analysis of study endpoints. All four biostimulators elicit a controlled inflammatory response characterized by macrophage infiltration and, in some cases, foreign-body giant cell formation. PLLA and PDLLA promote a transition from pro-inflammatory to pro-regenerative M2 macrophage phenotypes, driving sustained upregulation of Type I and III collagen, elastin, and angiogenesis. PCL induces durable neocollagenesis lasting up to 24 months, supported by neovascularization. CaHA stimulates fibroblast activity and ECM production, with a more pronounced early inflammatory gene signature than PLLA. Clinically, all biostimulators achieve significant and sustained improvements in wrinkle severity, skin quality, and volume restoration, with high patient satisfaction rates. Adverse events were predominantly mild and transient, with nodule formation being most notable with PLLA (4.7-28.6%). The study concluded that PLLA, PDLLA, PCL, and CaHA each elicit distinct yet overlapping inflammatory and cytokine-mediated cascades that culminate in robust neocollagenesis and tissue remodeling. Understanding these mechanistic differences enables clinicians to tailor treatment selection and protocols to achieve optimal, durable aesthetic outcomes with favorable safety profiles.

In this study, chlorine dioxide (ClO₂) was encapsulated within α-cyclodextrin (α-CD) via two approaches: in situ ClO₂ generation (EC) and effervescent tablets (ET). FTIR, XRD, TG-DTG, SEM, and water contact angle (WCA) analyses verified the successful formation of ClO₂/α-CD inclusion complexes and revealed distinct structural, thermal, and morphological differences between EC and ET. EC exhibited superior encapsulation efficiency (2.3% vs. 0.9% in ET), and slower ClO₂ release rates across varying storage temperatures, indicating stronger host - guest interactions and more robust structural integration. Kinetic analysis confirmed that ClO₂ release followed the first-order model for 1% and 5% groups and the zero-order model for the 3% group, with a non-Fickian anomalous diffusion mechanism controlled by both gas diffusion and polymer chain relaxation. The EC complex was incorporated into biodegradable PLA/PBAT composite films at varying concentrations (1-5%) to develop functional packaging materials. The incorporation of EC enhanced surface hydrophilicity but reduced tensile strength and light transmittance due to particle aggregation. At low loadings (1-3%), well-dispersed EC particles created a tortuous diffusion path and improved oxygen barrier properties. At 5% EC, excessive agglomeration induced microstructural defects and increased gas permeability, which was supported by microstructural observations. Grape preservation tests at 25 °C showed that PLA/PBAT/EC films effectively inhibited microbial spoilage and extended shelf life, despite a slight increase in mass loss related to higher water vapor permeability. In vitro antimicrobial evaluation against Rhizopus stolonifer further validated the concentration-dependent antibacterial activity of the films. These results highlight the potential of ClO₂/α-CD inclusion complexes for active food packaging applications. These results support the potential of EC-based ClO₂ complexes in active packaging systems for enhanced food preservation.

Facial laxity is a major aesthetic concern, often managed through energy-based skin-tightening devices. However, safety considerations arise when treating patients with atopic dermatitis (AD), due to barrier dysfunction, and in those with prior aesthetic procedures, where synergistic effects and risks remain unclear. We aimed to assess the safety and efficacy of a dual-mode radiofrequency (RF) device in 2 challenging clinical contexts: atopic-prone skin and previously treated skin. Two female patients underwent single-session treatment with a dual-mode monopolar-bipolar RF system (DENSITY, Jeisys Medical Inc., Seoul, Republic of Korea), with integrated contact cooling. Outcomes were assessed using standardized photography, patient-reported improvement, and monitoring for adverse events. Both patients exhibited clinically significant skin tightening, improved skin texture, and reduced fine lines. The patient with AD tolerated treatment without flares or complications. The previously treated patient (Ultherapy, botulinum toxin, poly-D,L-lactic acid boosters) reported complementary benefits beyond those achieved with earlier procedures. Both rated satisfaction as 4 out of 5. Treatment-related discomfort was reported as 6 out of 10 (AD patient) and 5 out of 10 (previously treated patient). Dual-mode RF seems to be safe and effective for addressing facial laxity in patients with atopic-prone skin and in those who have undergone prior aesthetic treatments. It may serve as a valuable adjunct or maintenance modality in facial rejuvenation.