Search Results (990)

Background/Objectives: Radiotherapy following mastectomy induces persistent structural alterations in the chest wall, including fibrosis, extracellular matrix disorganization, and vascular changes that compromise reconstructive outcomes. Although autologous fat grafting is widely used to improve tissue quality in irradiated breasts, direct human histological evidence remains limited. The aim of this prospective pilot study was to evaluate intra-patient histological remodeling in irradiated postmastectomy breast tissue before and 4 months after autologous fat grafting using paired core needle biopsies. This study should be considered a hypothesis-generating histological pilot study. Methods: Five female patients with prior mastectomy and adjuvant radiotherapy underwent Tru-Cut core needle biopsy of irradiated chest wall tissue before lipofilling and at approximately four months (range between 3 and 12 months) post-procedure. Specimens were processed using formalin fixation, paraffin embedding, and hematoxylin and eosin staining. Histological assessment focused on collagen density, stromal organization, vascular structures, inflammatory infiltrate, and adipocyte integration. Comparative intra-patient analysis was performed descriptively. Results: Baseline biopsies demonstrated consistent post-radiation alterations, including collagen compaction, stromal disorganization, perivascular fibrosis, and variable inflammatory infiltrate. Post-lipofilling specimens showed heterogeneous remodeling characterized by focal collagen fiber insertion between adipocytes, areas of immature connective tissue formation, and variable preservation of adipose architecture. The extent and pattern of remodeling differed among patients. Inflammatory activity decreased or remained mild in most cases. Conclusions: Autologous fat grafting in irradiated postmastectomy tissue is associated with measurable histological remodeling. Structural adaptation appears heterogeneous and patient-specific, suggesting a dynamic multi-stage process rather than uniform regeneration. Further studies incorporating quantitative and molecular analyses are required to clarify the mechanisms underlying these changes. Full article

To enhance the functionality of collagen (Coll)-based scaffolds, we developed a double-crosslinking strategy incorporating an electroconductive chitosan (Ch) and polypyrrole (Ppy) composite. Successful pre-crosslinking of Ch and Ppy was achieved using glutaraldehyde (GTA) at 100 µM. This facilitated imine linkage formation, confirmed by FTIR, enabling synergistic integration with Coll and successful nanofiber scaffold fabrication via electrospinning. While increasing the Ch-Ppy-GTA ratio affected the spinning process and higher GTA concentrations compromised fiber homogeneity, all other measured properties generally improved with increasing ratios. Crucially, this methodology allowed the membranes to maintain their morphology and significantly extended their degradation profile up to 20–30 days in PBS medium at 37 °C. Furthermore, the scaffolds exhibited electroactivity characterized by pseudocapacitance in the presence of Na⁺ and Ca²⁺ ions. These findings demonstrate a robust, tunable method for creating electroactive and structurally stable nanofiber scaffolds suitable for advanced tissue engineering. Full article

Skin aging is a complex biological process triggered by intrinsic and extrinsic factors, causing structural and functional deterioration, and its mitigation is a priority in cosmetology and functional food science. Skin fibroblasts, which mediate skin repair, wound healing and inflammation, are closely associated with aging. Sea cucumber collagen peptides exhibit prominent anti-aging, immunomodulatory and antioxidant properties, yet their mechanisms in ameliorating skin aging remain elusive, necessitating further exploration. This study verified the anti-skin aging efficacy of sea cucumber collagen peptides in D-galactose-induced aging mice, and explored whether the mechanism involves regulating endoplasmic reticulum (ER) stress in skin fibroblasts. Aging mice were gavaged with sea cucumber collagen peptides; skin moisture, barrier function and hydroxyproline content were measured, and skin morphology was observed. Immunofluorescence and Western Blot were used to detect ER stress-related proteins. Results showed that sea cucumber collagen peptides significantly improved aging mouse skin barrier function, elevated water and collagen fiber contents, and ameliorated the status of fibroblasts and prickle cells. The underlying mechanism may involve inhibiting ER stress in skin fibroblasts and enhancing prickle cell function. These findings confirm the peptides’ high bioavailability and potential as anti-aging functional food ingredients, providing insights for skin aging prevention. Full article

The in vivo effect of platelet-rich plasma (PRP) on supraspinatus tendon morphology and subacromial bursa cell gene expression in degenerative rotator cuff tears remains unclear. This randomized controlled trial evaluated the effect of preoperative leukocyte-poor PRP (LP-PRP) subacromial injection on supraspinatus tendon histology and subacromial bursa gene expression. Sixteen patients with full-thickness supraspinatus tears were randomized to receive an ultrasound-guided LP-PRP injection (n = 8) or no injection (n = 8) six weeks before arthroscopic repair. Tendon biopsies were assessed using the modified Movin score. Gene expression of collagen type I, II and III, metalloproteinase 3 and 13, and interleukin 1β and 6 genes from subacromial bursa cells was quantified using quantitative real-time PCR. The results of the two groups were compared to determine any statistically significant difference regarding all the examined parameters. The PRP group demonstrated a significantly lower total modified Movin score than controls (6.5 vs. 12.1, p = 0.002), with lower scores for fiber structure, fiber arrangement, nuclear rounding, inflammation and cell density (all p < 0.003), while angiogenesis did not differ (p = 0.149), indicating an architecture closer to that of normal tendon. No statistically significant differences in gene expression were observed (all p > 0.05), although collagen II and metalloproteinase 3 and 13 showed biologically relevant downregulation [fold change 0.23 (95%CI 0.05–1.09), 0.24 (95%CI 0.002–26.10), and 0.26 (95%CI 0.02–2.76), respectively]. The LP-PRP injection was associated with improved supraspinatus tendon histological characteristics and biologically relevant reductions in selected bursal genes, in the setting of supraspinatus tendon tear. Full article

In idiopathic azoospermia caused by non-obstructive infertility with AZFc deletion, the testicle usually contains an increased number of mast cells (MCs)—which are responsible for collagen synthesis in the testes—as well as Leydig cell hyperplasia. However, the relationship between MCs and telocytes in this pathology remains unexplored. The aim of this study was to examine ultrastructural changes in the interstitial tissue microenvironment of the convoluted seminiferous tubules in the testis, using clinical specimens from men with genetically determined non-obstructive infertility with AZFc deletion. Histological, immunohistochemical, and electron microscopic (EM) studies were performed on surgical materials from 14 patients with AZFc deletion. The IHC study was performed using a panel of antibodies: tryptase, chymase, carboxypeptidase A3, and αSMA. The EM study was performed on ultrathin sections with a thickness of 100–120 nm. MCs were found to be in a functionally active state and characterized by a variety of secretory activities. For the first time, telocytes and their colocalization with MCs and Leydig cells were visualized. It is possibly the telocytes—interacting with MCs—that synchronize the functional activity of the entire MC population of the testis. The interaction of MCs with telocytes, as well as individual secretory granules associated with loci of tropocollagen and collagen microfibril accumulation, leads to the accumulation of collagen fibrils in the interstitium, as observed in idiopathic infertility with AZFc deletion. Even with a small number of MCs in the interstitium of the convoluted seminiferous tubules in the testis, the telocytes are able to synchronize MCs’ activation and secretory activity, supporting the development of a profibrotic phenotype of the tissue microenvironment. The obtained results advance our understanding of idiopathic infertility with AZFc deletion by delineating the ultrastructural landscape of the testicular interstitium and establishing telocytes as key regulators of cellular crosstalk. Telocytes use complex mechanisms for the spatial integration of MCs and fibroblasts in the profibrotic phenotype formation of the convoluted seminiferous tubule tissue microenvironment. Potentially, telocytes can directly be involved in synchronizing such processes by activating the biogenesis and secretion of collagen monomers by fibroblasts; the MC secretome directly affects the polymerization of collagen monomers and dimers into microfibrils in the extracellular matrix, stimulating excessive collagen fiber formation and the development of fibrotic changes. Full article

Mechanical signals play key roles in the regulation of epidermal homeostasis and regeneration after injury. Integrins are key components of focal adhesions, and these complexes are major contributors to mechanotransduction. In keratinocytes, integrin-linked kinase (ILK) modulates essential processes for epidermal homeostasis and wound repair. However, its functions in the transduction of mechanical stimuli have remained virtually unexplored. In this study, we characterized epidermal tissues and primary keratinocytes from mice with epidermis-restricted inactivation of the Ilk gene (ILK-KO). ILK-deficient epidermis exhibits abnormalities in key components of mechanotransduction cascades, including disruptions in hemidesmosomal Collagen XVII immunoreactivity at the dermal–epidermal junction, and marked reduction in the nuclear localization of the mechanosensitive transcriptional regulator YAP. In wild-type (ILK+), but not in ILK-KO-cultured keratinocytes, exposure to cyclic bidirectional strain induced marked F-actin cytoskeletal rearrangements, characterized by the assembly of thick cortical actin bundles and stress fibers, as well as YAP nuclear translocation and transcriptional activity. Exposure to mechanical strain was additionally accompanied by differential changes in miRNA expression between ILK+ and ILK-KO cells. These findings reveal multiple and previously unappreciated key regulatory roles for ILK in epidermal keratinocyte responses to mechanical signals. Full article

This study explored ultrastructural changes and the expression of oxidative stress-related genes and proteins in the laminar tissue of dairy cows with acute laminitis induced by oligofructose (OF) overload. Twelve clinically healthy, non-pregnant Chinese Holstein cows were randomly allocated into two groups: the OF-overload group (n = 6) and the control group (n = 6). 17 g/kg BW of oligofructose (OF) dissolved in 20 mL/kg BW of deionized water was provided to the OF-treated group, while the control group received 20 mL/kg BW of deionized water via a stomach tube. Laminar tissue samples were collected at 72 h post-OF administration. RT-qPCR revealed significantly increased Keap1 mRNA expression (p = 0.0097) and significantly decreased Nrf2 (p < 0.0001), Ho1 (p < 0.0001), and Nqo1 (p = 0.0101) mRNA expression in the OF group compared to the control group. Western blot analysis confirmed corresponding protein-level changes, with significantly increased Keap1 (p = 0.0062) and significantly decreased Nrf2 (p = 0.0008), Ho1 (p = 0.0297), and Nqo1 (p = 0.0004) in the OF group compared with the control group. Immunohistochemical analysis revealed significantly increased cytoplasmic Keap1 distribution (p = 0.0200) and significantly decreased nuclear Nrf2 localization (p = 0.0032) in the OF group than the control group. Ultrastructural examination revealed significant pathological changes in the OF group, including a reduced number of hemidesmosomes (p < 0.01), an increased distance from epidermal basal cells to the lamina densa (p < 0.01), thickened and damaged lamina densa with disorganized collagen fibers, and deformed basal cell nuclei with reduced chromatin relative to the control group. In conclusion, these findings demonstrate that OF-induced acute laminitis is associated with significant dysregulation of the Keap1-Nrf2 antioxidant pathway and severe ultrastructural damage to the dermal–epidermal interface, suggesting that oxidative stress contributes to laminar tissue injury in dairy cows. Full article

Effective management of acute, complex, and chronic wounds requires constructs that simultaneously support tissue repair and provide sustained infection control. Biologic-derived materials, despite their regenerative potential, are limited by insufficient long-term antibacterial activity and susceptibility to enzymatic degradation. To overcome these limitations, a fully absorbable synthetic matrix composed of electrospun composite fibers functionalized with polyhexamethylene biguanide (PHMB) (hereafter, PHMB Matrix) was developed to mimic extracellular matrix architecture while enabling durable antibacterial performance. Quantitative assessment per AATCC 100 demonstrated robust broad-spectrum efficacy (>99.99% reduction) against six clinically relevant Gram-positive and Gram-negative pathogens, with potency retained after 15 months of real-time aging. The matrix’s interconnected fibrous architecture enables a controlled, biphasic PHMB release coordinated with biodegradation, sustaining antibacterial protection throughout a 28-day healing period. In porcine full-thickness wound models, the PHMB Matrix achieved 63.53% ± 12.0% wound area reduction by Day 22, demonstrating accelerated mid-phase healing compared to an antibacterial collagen control (p < 0.05 on Day 22), with both treatments achieving comparable near-complete closure by Day 28. Pharmacokinetic analysis confirmed localized drug enrichment with negligible systemic exposure. These findings establish the PHMB-functionalized synthetic matrix as a safe, effective, fully absorbable alternative to biologic-derived materials for soft tissue repair, offering sustained antibacterial efficacy and a favorable safety profile. Full article

Hair loss affects over half of adults by age 70 and represents a major determinant of overall hair health, imposing significant psychosocial burden across genders. Nutritional factors play a critical role in follicle biology, yet targeted strategies remain underexplored. This comprehensive review examines five key hair-constituent macromolecules—type I collagen, elastin, keratin, ceramides, and melanin—and their physiological and clinical impacts on hair structure, density, shining, and growth. We conducted a structured literature search in PubMed and Google Scholar through January 2025, selecting in vitro studies, animal experiments, and human clinical trials that evaluated each macromolecule’s effects on follicular function and hair fiber integrity. Type I collagen enhances dermal papilla cell proliferation, upregulates Wnt/β-catenin and growth factors, and improves hair thickness and breakage resistance in randomized controlled trials. Keratin hydrolysates replenish cortical protein, reinforce disulfide cross-links, and reduce telogen shedding, with clinical studies demonstrating 30–50% decreases in hair loss and gains in tensile strength. Oral ceramide formulations restore the cuticular lipid barrier, shift follicles toward anagen, and increase hair density in double-blind trials. Although direct clinical data on melanin supplementation are lacking, ex vivo and animal models confirm its role as a UV-protective pigment, preserving keratin integrity and color fastness. Together, these macromolecules constitute a coherent framework for hair health, and clinical studies increasingly provide evidence that their combined or parallel application can meaningfully enhance hair density, strength, shine, and resilience. Full article

Wounds caused by Vibrio vulnificus (V. vulnificus) infection often exhibit delayed healing and are prone to complications, making them a significant challenge in clinical treatment. Current conventional treatments, such as antibiotics and gauze dressings, have limited effectiveness. To address this, this study developed a multifunctional fiber membrane using electrospinning technology. Micron- or nano-sized Haliotidis Concha (HC) and eugenol (Eu) were loaded onto the membrane to promote healing in V. vulnificus-infected wounds. The prepared fiber membranes exhibited diameters of approximately 0.35 ± 0.01 μm. Membranes loaded with nano-HC demonstrated significant antibacterial efficacy, achieving a 96.2% inhibition rate against V. vulnificus, which was markedly superior to the micron-HC group (p < 0.05). Notably, the nano-HC/Eu membranes exhibited exceptionally high flexibility with an elongation at break of 878.1 ± 35.3%, while maintaining a tensile strength of approximately 2.2 MPa. Furthermore, these membranes exhibited excellent biocompatibility, with cell viability exceeding 85% for fibroblasts, and demonstrated good hemocompatibility. They also effectively promoted cell migration, indicating their potential as wound scaffold materials. In a V. vulnificus-infected skin wound model, the nano-HC/Eu fiber membrane accelerated collagen deposition and promoted wound healing, achieving a wound closure rate of 94.7 ± 1.1% on day 15. In summary, this study developed a multifunctional fiber membrane with antibacterial, antioxidant, and wound healing properties, offering a novel dressing for treating V. vulnificus infections. Full article

Background: The attached gingiva (AG) is the portion of the gingiva firmly bound to the underlying alveolar bone and root cementum, rendering it immobile during functioning. Its dense connective tissue attachment contributes to resistance against mechanical challenges, stabilization of the gingival margin, and dissipation of forces transmitted from the alveolar mucosa. Histologically, AG is characterized by a keratinized epithelium supported by dense collagen fiber bundles, which provide structural integrity to the dento–gingival unit. Clinically, the buccal and lingual width of AG is estimated by subtracting sulcus depth from the total width of keratinized tissue. Although periodontal health may be maintained with minimal AG under optimal plaque control, substantial evidence supports its role in preserving gingival architecture and resisting mechanical trauma. Practical Application: From a clinical perspective, an adequate width of attached gingiva has traditionally been considered necessary to protect the periodontium; however, clinical situations may exist in which its dimension is reduced or absent. Available evidence suggests that a minimal width of approximately 1 mm of attached gingiva may be sufficient to maintain periodontal health under conditions of effective plaque control and absence of inflammation. Nevertheless, when only this minimal dimension is present, the attachment is predominantly derived from the junctional epithelium, which may offer limited mechanical protection to the dento–gingival unit. Within the limits of current evidence, a keratinized tissue width of approximately 3 mm appears to represent a functional threshold associated with increased connective tissue fiber density and enhanced resistance to mechanical trauma. Methods: A narrative review of classical and contemporary literature was conducted to evaluate the morphology, histology, function, and clinical relevance of the attached gingiva. Results: Evidence indicates that when AG width is minimal, reliance on junctional epithelial attachment alone provides limited resistance to mechanical challenges. In contrast, a greater width of AG incorporating connective tissue fiber attachment is associated with improved gingival margin stability, enhanced mechanical protection, and periodontal tissue resilience. Based on this synthesis, a tissue-based clinical categorization of AG is proposed. Conclusions: This review integrates current biological and clinical concepts regarding the functional dimensions of attached gingiva. The proposed categorization offers a practical framework to support clinical decision-making and to identify conditions in which surgical augmentation may be indicated for the management of mucogingival deficiencies. Full article

We evaluated human embryonic stem cell-derived mesenchymal stem cells (ES-MSCs) on collagen scaffolds for meniscus-like neotissue formation and ex vivo repair of human osteoarthritic (OA) meniscal defects. Collagen type I fibrous scaffolds were pneumatospun, and laminate scaffolds were fabricated from electrospun PLA/collagen; crosslinked; heparin conjugated; fibronectin coated; functionalized with TGFβ1, TGFβ3, or PDGFbb; seeded with ES-MSCs; and cultured for 4 weeks, followed by in vitro assessment or ex vivo implantation into 3.5 mm human meniscus defects for 5 weeks. Pneumatospinning generated highly porous scaffolds that supported uniform cell infiltration, while laminate scaffolds demonstrated interlocking fiber interfaces and enhanced mechanical properties. TGFβ1 and TGFβ3 immobilization enhanced scaffold bioactivity, defined as growth factor-mediated increases in meniscus-like matrix deposition, collagen fiber organization, and meniscogenic gene expression, by significantly increasing safranin O staining, collagen type II deposition, collagen fiber polarization, and ACAN expression. TGFβ3 additionally increased COL1A1 expression and pushout shear modulus; TGFβ1 increased peak pushout stress, indicating superior ex vivo mechanical integration. Laminate scaffolds resulted in extensive cell infiltration, robust neotissue formation (elastic modulus ~2.4 MPa), and improved ex vivo tissue integration when functionalized with TGFβ3. The data indicated that ES-MSC-seeded, heparin-conjugated, TGFβ-immobilized pneumatospun/electrospun collagen–PLA scaffolds support meniscogenic differentiation and biomechanical integration, with repair of focal meniscal defects and potential for partial meniscus replacement. Full article

Acute and chronic wounds are a major clinical burden, with persistent inflammation, impaired fibroblast function, defective angiogenesis, and disordered extracellular matrix deposition. The translational potential of existing in vitro models is limited by their poor durability and physiological relevance. The present paper aims to develop a robust in vitro organotypic model to simulate the early phases of both acute and chronic wounds and to validate it by testing the biocompatibility of clinically available wound dressings. Human fibroblasts and vascular endothelial cell lines were cultured at a ratio of 1:1 for 48 h, either on uncoated tissue culture plastic or on tissue culture plastic coated with a synthetic substrate (PhenoDrive-Y) that biomimics the extracellular matrix and promotes cell organization into tissue-like structures on a 2D plane (i.e., angiogenesis sprouting and fibroblast organization around it). Wound conditions were then created by damaging the formed structures using a conventional scratch procedure and introducing U937 human macrophage cells to the model to simulate either the onset of an acute wound or that of a chronic wound through the simultaneous spiking of the culture with relevant cytokines, i.e., IL-6 and TNF-α. The formation of new tissue-like structures in the scratch area was quantified by the extent of scratch closure after a further 24 h of incubation. Morphological analysis of wound healing was performed by light microscopy, while angiogenesis was assessed by CD31 immunostaining by confocal microscopy. The deposition of components of the extracellular matrix was determined both qualitatively and quantitatively by Picrosirius Red staining for collagen production and by Alcian Blue staining for glycosoaminoglycan synthesis on the adhering cells and their supernatants. Macrophage polarization into either M1 or M2 phenotype was studied by immunostaining with iNOS (M1) and CD206 (M2) antibodies by confocal microscopy. The model was validated by studying the gap closure areas in simulated acute and chronic wound-like conditions when incubated with clinically available wound dressings, N-A Ultra and Kaltostat. PhenoDrive-Y allowed the formation of tissue-like structures on the 2D tissue culture plane as opposed to the formation of cell monolayers on the uncoated tissue culture plastic. Upon mechanical damage, cell migration was significantly different; uncoated control co-cultures achieved complete closure as an indistinct monolayer by 24 h, while the organotypic wound models showed a slower percentage of damage closure. A further delay in the closure of the damaged area was observed when chronic wound-like conditions were simulated. Angiogenesis in chronic wound conditions was considerably impaired compared to the acute conditions. The analysis of the extracellular matrix component synthesis, specifically collagen and polysaccharides, revealed the deposition of dense, organized collagen fibers in the acute wound model, in contrast to the thin, fragmented collagen fibers and intracellular polysaccharides observed under chronic wound-like conditions. This corresponded to a statistically significant increase in the levels of both collagen and polysaccharides detected as soluble molecules in the supernatants. Macrophage polarization showed no statistically significant differences in the acute and chronic wound models, though iNOS did significantly decrease after N-A application in acute and chronic models. However, acute wound-like conditions showed a restoration of the vascularized tissue-like structures after treatment with these types of dressings, albeit through different organizational pathways, whereas only minimal improvement was noted under chronic wound conditions, particularly in the case of the N-A dressing. The organotypic dermis model for the onsets of acute and chronic wounds emerges as a highly versatile tool to understand healing mechanisms in the absence or presence of co-morbidities and to assess the biocompatibility of wound dressings as well as the safety, efficacy and dosage of drugs. Full article

Facial aging is primarily characterized by the loss and disorganization of the dermal extracellular matrix (ECM), particularly collagen. Injectable biostimulators, such as calcium hydroxyapatite (CaHA), represent a vital non-surgical strategy to counteract these changes by inducing neocollagenesis. This 90-day clinical trial was designed to comparatively evaluate the efficacy of a novel regenerative solution (RS) diluent, formulated to potentially enhance the biostimulatory effects of standard CaHA (STIIM product), against a conventional diluent (control) for the treatment of facial laxity. Twenty-one subjects (N = 21) were randomized to receive CaHA diluted with either RS or control formulation. Efficacy was assessed using histological analysis (collagen I area percentage), ultrasound (US) for dermal density, and clinical laxity scoring. Histological analysis, although limited by a small subsample size (N = 3), showed qualitative and exploratory evidence of collagen remodeling in both groups. However, the RS group showed enhanced dermal thickening via US (15% increase vs. 5% control, p-value = 0.012), and improvement in clinical laxity. Furthermore, histological findings, including Picrosirius red staining, indicated that the RS group resulted in qualitatively greater ECM organization and more robust type I collagen fibers compared to the control. The novel regenerative solution is safe and demonstrates enhanced neocollagenesis and clinical efficacy over the conventional formulation, validating its potential as a diluent for CaHA for optimized facial rejuvenation. Full article

Background: Surgical tendon rupture repair suffers from scar formation, leading to tendons with inferior mechanics and consequently to re-ruptures, as well as from adhesion formation to the surrounding tissue, reducing the range of motion. In an approach of re-purposing the phytochemical Bakuchiol to be incorporated in the polymer DegraPol^® (DP), we fabricated a novel implant material by emulsion electrospinning. Methods: To characterize the emulsion electrospun novel materials, we used Scanning Electron Microscopy (SEM) to determine the fiber diameter and pore size. In addition, we used Fourier Transformed Infrared Spectroscopy (FTIR). Finally, we planted the materials onto the chorioallantoic membrane of the chicken embryo (CAM assay) to assess tissue integration and collagen expression. Results: While the pure DP meshes were very well integrated in the CAM assay and showed a significantly higher collagen deposition within the scaffold, the DP + Bakuchiol meshes exhibited poor tissue integration, showing rather the beginning of a fibrous encapsulation. Conclusions: The novel electrospun material DP + Bakuchiol could be used as an anti-adhesion barrier to prevent tendon adhesion. Full article