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Excimer laser treatment combined with riboflavin ultraviolet-A (UVA) collagen crosslinking (CXL) in keratoconus: a literature review
摘要： Purpose To review the clinical outcome of keratoconus patients after excimer laser treatment with combined riboflavin UV-A collagen crosslinking (CXL) treatment was reviewed in light of the UDVA, CDVA and HOA. Methods Following a PubMed-based literature review of studies on excimer laser treatment with combined riboflavin UV-A CXL published between 2009 and 2018, peer-reviewed English-written studies were evaluated using the GRADE approach (www.gradeworkinggroup.org). The current review focused on the change in the (un)corrected distance visual acuity (UDVA; CDVA) and higher-order aberrations (HOA) as well as the prevalence of postoperative complications. Results Five studies with a total of 573 eyes were included, thereby reporting on 479 eyes were treated with the aforementioned combination therapy. The control group consisted of 94 eyes in total. Changes between pre- and postoperative CDVA and/or UDVA were statistically significant in all five studies after at least a 24-month follow-up period for the combined excimer laser-assisted CXL treatment in comparison with the CXL-only treatment option. Three studies described statistically significant reduction in the number of total HOA, in particular, those related to coma and spherical aberration. Corneal haze was reported in four studies, but the condition was successfully treated in all cases. Conclusion Current studies suggest that CDVA, UDVA and HOA in low-to-moderate keratoconic patients improved in a combined treatment without sacrificing biomechanical stability of the cornea. However, long-term results are needed, as the studies in our review have a follow-up period of 68 months or less.
关键词： Refractive surgery,Keratoconus,Collagen-crosslinking,Photorefractive keratectomy
更新于2025-09-23 15:21:01
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Alteration of lens and retina textures from mice embryos with folic acid deficiency: image processing analysis
摘要： Purpose Folic acid (FA) is an essential vitamin for embryonic development. It plays particularly a critical role in RNA, DNA and protein synthesis. On the other hand, the collagen IV and laminin-1 are important proteins during embryonic development. This study was done to find if FA deficiency at a short and a long term in mothers could alter the tissue texture of retina and lens of the progeny. Methods Collagen IVand laminin-1 were localized by immunohistochemistry in the lens and retina of the FA-deficient embryos. To carry out the image processing, texture segmentation was performed through canny edge detection and Fourier transform (FT). We defined a parameter, the grain size, to describe the texture of the lens and retina. A bootstrap method to estimate the distribution and confidence intervals of the mean, standard deviation, skewness and kurtosis of the grain size has been developed. Results Analysis through image processing using Matlab showed changes in the grain size between control- and FA-deficient groups in both studied molecules. Measures of texture based on FT exhibited changes in the directionality and arrangements of type IV collagen and laminin-1. Conclusions Changes introduced by FA deficiency were visible in the short term (2 weeks) and evident in the long term (8 weeks) in both grain size and orientation of fibre structures in the tissues analysed (lens and retina). This is the first work devoted to study the effect of FA deficit in the texture of eye tissues using image processing techniques.
关键词： Matlab texture analysis,Laminin-1,Lens,Type IV collagen,Folic acid deficiency,Retina
更新于2025-09-23 15:21:01
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Topical administration of a ROCK inhibitor prevents anterior subcapsular cataract induced by UV-B irradiation
摘要： The deposition of extracellular matrix (ECM)—which is mainly composed of type I collagen—in anterior subcapsular cataracts (ASCs) during epithelial-to-mesenchymal transition (EMT) of lens epithelial cells (LECs) decreases visual function. Transforming growth factor (TGF)-β is a key factor in the induction of EMT in LECs. Although Rho kinase (ROCK) plays an important role in EMT induced by TGF-β, it is unknown whether ROCK inhibition affects type I collagen expression in TGF-β-stimulated LECs and ASC formation. This was investigated in the present study both in vitro using human lens epithelium (HLE)-B3 cells and in vivo using mice with ultraviolet radiation (UVR)-B-induced cataracts. We found that TGF-β2 increased type I collagen mRNA expression in HLE-B3 cells; this was inhibited in a dose-dependent manner by treatment with the ROCK inhibitor Y-27632. UVR-B exposure caused ASC formation in mice. A histopathological examination revealed that LECs in the anterior subcapsular area were flattened and multi-layered, and had a spindle shape in cross section. Immunohistochemical analysis revealed the presence of α-smooth muscle actin and type I collagen around these flattened LECs; these opacities were reduced by topical instillation of Y-27632. These findings suggest that suppression of TGF-β signaling in LECs by topical application of a ROCK inhibitor can prevent the formation of ASCs.
关键词： lens epithelial cell,ROCK inhibitor,type I collagen,transforming growth factor-β,epithelial-to-mesenchymal transition
更新于2025-09-19 17:15:36
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Resolving Fine Electromechanical Structure of Collagen Fibrils via Sequential Excitation Piezoresponse Force Microscopy
摘要： Collagen is the main protein in extracellular matrix that is found in many connective tissues, and it exhibits piezoelectricity that is expected to correlate with its hierarchical microstructure. Resolving fine electromechanical structure of collagen, however, is challenging, due to its weak piezoresponse, rough topography, and microstructural hierarchy. Here we adopt the newly developed sequential excitation (SE) strategy in combination with piezoresponse force microscopy (PFM) to overcome these difficulties. It excites the local electromechanical response of collagen via a sequence of distinct frequencies, minimizing crosstalk with topography, followed by principal component analysis (PCA) to remove the background noise and simple harmonic oscillator (SHO) model for physical analysis and data reconstruction. These enable us to acquire high fidelity mappings of fine electromechanical response at the nanoscale that correlate with the gap and overlap domains of collagen fibrils, which show substantial improvement over conventional PFM techniques. It also embodies the spirit of big data atomic force microscopy (AFM) that can be readily extended into other applications with targeted data acquisition.
关键词： Principal component analysis,Sequential excitation,Simple harmonic oscillator model,Piezoresponse force microscopy,Collagen
更新于2025-09-19 17:15:36
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A Dermonutrient Containing Special Collagen Peptides Improves Skin Structure and Function: A Randomized, Placebo-Controlled, Triple-Blind Trial Using Confocal Laser Scanning Microscopy on the Cosmetic Effects and Tolerance of a Drinkable Collagen Supplement
摘要： The purpose of this randomized, placebo-controlled, triple-blind trial on 60 healthy female volunteers was to assess the cosmetic effects on skin quality of a food supplement containing special collagen peptides together with acerola extract, vitamin C, vitamin E, biotin, and zinc after an intake of 12 weeks (Elasten(cid:2), QUIRIS Healthcare, Germany). To reduce assessment bias maximally and increase the accuracy and objectivity of the outcomes, the trial design was triple blinded in a manner that neither the subjects nor the person administering the products nor the person who assessed the primary outcomes knew which subjects had received the test product and which had received the placebo. The expert grader assessing the confocal laser scanning microscopy images was additionally blinded regarding the time when the image was taken (on days 1 or 85). The objective, blinded, and validated image analyses using confocal laser scanning microscopy showed a signi?cant improvement of the collagen structure of facial skin (primary endpoint) after intake of the test product, while no improvements were found after intake of the placebo. The proven positive nutritional effect on the collagen structure was fully consistent with positive subjective evaluations of relevant skin parameters such as elasticity, crinkliness/wrinkliness, and evenness in different body areas such as face, hands, de′collete′, neck, backside, legs, and belly, all serving as secondary endpoints. The test product was found to be safe and very well tolerated. A cosmetically relevant improvement of the facial skin was demonstrated after administration of the collagen supplement.
关键词： dermonutrient,antiaging,skin beauty,collagen peptides,dermal collagen structure,oral collagen supplement
更新于2025-09-19 17:13:59
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Ablative fractional laser resurfacing for treatment of sclerosis and contractures in chronic graft-versus-host disease: A pilot study
摘要： To the Editor: Cutaneous sclerosis is a disabling complication of chronic graft-versus-host disease (cGVHD) that leads to joint contractures and reduced range of motion (ROM). Current therapies are limited by adverse effects and poor efficacy, and no systemic treatment successfully reverses cGVHD-induced sclerotic skin changes.1 There is an urgent need for therapies to address the debilitating effects of cutaneous sclerosis in cGVHD. The ablative fractional CO2 laser remodels collagen and reduces fibrosis. It has been used for treatment of scars and contractures secondary to linear morphea, burns, and traumatic injury, conditions resembling the sclerosis of cGVHD.2,3 We evaluated the safety, tolerability, and efficacy of the ablative fractional CO2 laser for cGVHD-related sclerosis and joint contractures. Six patients with cGVHD-related sclerosis were enrolled prospectively and completed the study. Eligible patients had clinically severe, refractory sclerosis from longstanding cGVHD, with demonstrable ROM limitation and contractures across a joint amenable to laser therapy. After administration of topical anesthesia, patients had 3 monthly treatments of an approximately 10 3 6-cm area of skin at the target joint using the 10 600-nm fractional Ultrapulse CO2 laser (Ultrapulse Encore; Lumenis, Inc, Santa Clara, CA) in Deep FX mode (energy settings, 20-25 mJ; density, 5%-15%). Photographs, ROM measurements, and high-resolution ultrasonography were recorded at baseline, 1 week after each laser session, and 3 months after the final session. Punch biopsy and patient and provider assessments, including validated health and disability questionnaires, were performed at baseline and 3 months after the final session. The study was approved by the University of Pennsylvania institutional review board, and all patients provided written informed consent. Before enrollment, patients had received a mean of 5.5 systemic therapies for cGVHD-related sclerosis. Laser treatments were well tolerated, without infectious or other serious complications. ROM measurements, particularly the twisting motions of supination and pronation, improved in all patients (Table I). Immunohistochemical analysis of skin biopsy specimens showed decreased thickened collagen bundles, decreased intensity of collagen staining, and greater abundance of type III collagen in treated areas (Fig 1).3 Dermal echogenicity measured via high-resolution ultrasonography increased after the laser treatment, suggestive of collagen remodeling. Less haphazard organization of collagen is postulated to produce increased echogenicity.4 Patient photographs and disability assessments similarly showed evidence of improvement. The results of this pilot study highlight the safety, tolerability, and potential efficacy of the fractional ablative CO2 laser for treatment of cGVHD-related sclerosis and joint contracture, resulting in small but measurable histologic, radiologic, and functional improvements. Small sample size, small treatment area, and imperfect objective response measures are limitations. Longer follow-up, larger treatment areas, use of other laser settings, and laser-assisted delivery of topical medications should be evaluated in future studies.5 In summary, the fractional ablative CO2 laser was safe and well tolerated in a small group of medically complex patients with treatment-refractory cGVHD. Treatment of a target area of sclerotic skin appeared to induce collagen remodeling, with resulting modest improvement in ROM and joint function. These findings suggest that the fractional ablative CO2 laser may be an effective novel therapy for disabling sclerotic joint contractures in some patients with cGVHD.
关键词： sclerosis,ablative fractional laser resurfacing,contractures,chronic graft-versus-host disease,collagen remodeling
更新于2025-09-16 10:30:52
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Genitourinary syndrome of menopause (GSM) and laser VEL: a review
摘要： The purposeof this publication is to summarize the results of the vaginal erbium:yttrium-aluminum-garnet (Er:YAG) Smooth? laser (VEL) on the vaginal atrophy component of the genitourinary syndrome of menopause (GSM). GSM has two categories of clinical signs related to estrogen deficiency: symptoms of vulvovaginal atrophy (VVA) and urinary symptoms. This symptomatology is chronic, progressive over the years and affects a majority of women concerned by natural menopause but not exclusively: we must also consider the growing number of survivors of gynecological or non-gynecological cancers (breast, cervix, uterus, vagina, anus, etc.). At a time when hormonal treatment of menopause is contested as is the installation of under urethra prosthesis, the innovation provided by the VEL technology has the merit of offering the women concerned an effective therapeutic alternative with the security of a patent. The VEL technology has an original and unique process: acting only by thermal effect and not by ablation on tissue, VEL is a safe solution in terms of side effects and potential complications. Studies have been increasing since 2012 and all demonstrate a significant improvement in the GSM signs and symptoms, as well as an improved sexual life after VEL treatment. Double-blind, placebo-controlled, randomized studies are expected in order to ultimately confirm the safety and effectiveness of VEL.
关键词： dyspareunia,genitourinary syndrome of menopause,gynecological cancers,collagen,vaginal atrophy,menopause,laser erbium Smooth?
更新于2025-09-12 10:27:22
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High- Versus Low-Density Fractional Laser in the Treatment of Hypertrophic Postburn Scars
摘要： BACKGROUND Fractional CO2 laser has been shown effective in improving pigmentation, pruritus, and tightness of hypertrophic burn scars. However, there is no consensus on the optimal treatment parameters. OBJECTIVE To compare effectiveness of different densities of fractional CO2 laser in the treatment of mature hypertrophic burn scars. MATERIALS AND METHODS The study included 25 patients, each with 3 or more mature hypertrophic burn scars. Scars were randomly assigned to treatment with low-, medium-, and high-density fractional CO2 laser. Each scar received 3 sessions of laser at 1-month interval. The degree of improvement was assessed clinically using Vancouver Scar Scale (VSS) and Patient and Observer Scar Assessment Scale (POSAS) scores, and histologically through evaluation of collagen (Masson’s Trichrome stain) before and 1 month after end of therapy. RESULTS High-density parameters showed significant higher improvement in VSS and POSAS assessment scores (p-value < .001). Pliability and relief are the most improved parameters. Histopathological evaluation revealed a significant drop in the mean area percent of collagen in the 3 used parameters, with highest improvement with high-density laser treatment (p-value < .001). CONCLUSION High-density fractional CO2 laser treatment provides more improvement in burn scars both clinically and histopathologically.
关键词： hypertrophic burn scars,collagen,Fractional CO2 laser,Patient and Observer Scar Assessment Scale,Vancouver Scar Scale
更新于2025-09-12 10:27:22
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Transformation of the dermal collagen framework under laser heating
摘要： The aim of this study was to compare between the changes undergone by the framework when dermal collagen heated by IR laser radiation and by traditional means and to reveal the specific features of the dermal matrix modification under moderate IR laser irradiation. Rabbit skin specimens were heated to 50°C, 55°C, 60°C and 65°C in a calorimeter furnace and with a 1.68-μm fiber Raman laser. The proportion of the degraded collagen macromolecules was determined by differential scanning calorimetry. Changes in the architectonics of the collagen framework were revealed by using standard, phase-contrast, polarization optical and scanning electron microscopy techniques. The collagen denaturation and dermal matrix amorphization temperature in the case of laser heating proved to be lower by 10°C than that for heating in the calorimeter furnace. The IR laser treatment of the skin was found to cause a specific low-temperature (45°C-50°C) transformation of its collagen framework, with some collagen macromolecules remaining intact. The transformation reduces to the splitting of collagen bundles and distortion of the course of collagen fibers. The denaturation of collagen macromolecules in the case of traditional heating takes its course in a threshold manner, so that their pre-denaturation morphological changes are insignificant.
关键词： calorimetry,collagen transformation,skin,laser heating
更新于2025-09-11 14:15:04
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Extracellular Collagen Promotes Interleukin-1β–Induced Urokinase-Type Plasminogen Activator Production by Human Corneal Fibroblasts
摘要： PURPOSE. Keratocytes maintain homeostasis of the corneal stroma through synthesis, secretion, and degradation of collagen fibrils of the extracellular matrix. Given that these cells are essentially embedded in a collagen matrix, keratocyte–collagen interactions may play a key role in regulation of the expression or activation of enzymes responsible for matrix degradation including urokinase-type plasminogen activator (uPA), plasmin, and matrix metalloproteinases (MMPs). We examined the effect of extracellular collagen on the production of uPA by corneal fibroblasts (activated keratocytes) stimulated with the proinflammatory cytokine interleukin-1b (IL-1b). METHODS. Human corneal fibroblasts were cultured either on plastic or in a three-dimensional gel of type I collagen. Plasminogen activators were detected by fibrin zymography, whereas the IL-1 receptor (IL-1R) and MMPs were detected by immunoblot analysis. Collagen degradation by corneal fibroblasts was assessed by measurement of hydroxyproline in acid hydrolysates of culture supernatants. RESULTS. Collagen and IL-1b synergistically increased the synthesis and secretion of uPA in corneal fibroblasts. Collagen also upregulated IL-1R expression in the cells in a concentration-dependent manner. The conversion of extracellular plasminogen to plasmin, as well as the plasminogen-dependent activation of MMP-1 and MMP-3 and degradation of collagen apparent in three-dimensional cultures of corneal fibroblasts exposed to IL-1b, were all abolished by a selective uPA inhibitor. CONCLUSIONS. Collagen and IL-1b cooperate to upregulate uPA production by corneal fibroblasts. Furthermore, IL-1b–induced collagen degradation by these cells appears to be strictly dependent on uPA expression and mediated by a uPA–plasmin–MMP pathway.
关键词： corneal wound healing,urokinase,collagen degradation
更新于2025-09-11 14:15:04