Elastin Fibers Research Articles

Biomimetic vascular tissue engineering by decellularized scaffold and concurrent cyclic tensile and shear stresses

Decellularization by chemical approaches has harmful effects on extracellular matrix (ECM) proteins, and damages lots of functional peptides and biomolecules present in the ultrastructure. In this study, we employed a combination of chemical and physical decellularization methods to overcome these disadvantages. The induced osmotic pressure by hypertonic/hypotonic solutions dissociated and removed most of cellular membranes significantly without any detergent or chemical agent. In total, 0.025% trypsin solution was found adequate to remove the remaining debrides, and ultimately 1% Triton X-100 was utilized for final cleansing. In addition, conducting all the decellularization processes at 4 °C yielded an ECM with least damages in the ultrastructure which could be inferred by close mechanical strength and swelling ratio to the native vessel, and high quality and quantity of cell attachment, migration and proliferation which were examined by optical microscopy and scanning electron microscopy (SEM) of the histology samples. Moreover, the obtained biological scaffold (BS) had no cytotoxicity according to the MTT assay, and this scaffold is storable at −20 °C. Employing bioreactor for concurrent cyclic tensile and shear stresses improved the cell migration into pores of the BS and made the cells and the scaffold compact in analogous to native tissue. As opening angle test showed by decellularizing of the blood vessel, the residual stress dropped significantly which revealed the role of cells in the amount of induced stress in the structure. However, intact and healthy ECM explicitly recovered upon recellularization and beat the initial residual stress of the native tissue. The tensile test of the blood vessels in longitudinal and radial directions revealed orthotropic behavior which can be explained by collagen fibers direction in the ECM. Furthermore, by the three regions of the stress–strain curve can be elucidated the roles of cells, elastin and collagen fibers in mechanical behavior of the vascular tissues.Graphical

A survey of elastase-producing bacteria and characteristics of the most potent producer, Priestia megaterium gasm32.

Ninety-one elastase-producing bacterial isolates were recovered from different localities of the Eastern Province of Saudi Arabia. Elastase from the best isolate Priestia megaterium gasm32, from luncheon samples was purified to electrophoretic homogeneity using DEAE-Sepharose CL-6B and Sephadex G-100 chromatographic techniques. The recovery was 17.7%, the purification fold was 11.7x, and the molecular mass was 30 kDa. Enzymatic activity was highly repressed by Ba2+ and almost completely lost by EDTA, but it was greatly stimulated by Cu2+ ions, suggesting a metalloprotease type. The enzyme was stable at 45°C and pH 6.0-10.0 for 2 hours. Ca2+ ions considerably enhanced the stability of the heat-treated enzyme. The Vmax and Km against the synthetic substrate elastin-Congo red were 6.03 mg/mL, and 8.82 U/mg, respectively. Interestingly, the enzyme showed potent antibacterial activity against many bacterial pathogens. Under SEM, most bacterial cells showed loss of integrity, damage, and perforation. SEM micrographs also showed a time-dependent gradual breakdown of elastin fibers exposed to elastase. After 3 hours, intact elastin fibers disappeared, leaving irregular pieces. Given these good features, this elastase may be a promising candidate for treating damaged skin fibers with the inhibition of contaminating bacteria.

Adverse pulmonary effects after oral exposure to copper, manganese and mercury, alone and in mixtures, in a Spraque-Dawley rat model

ABSTRACT The rise in respiratory disease has been attributed to an increase in environmental pollution. Heavy metals contribute to environmental contamination via air, water, soil and food. The effects of atmospheric exposure to heavy metals on pulmonary structure and function have been researched, but the effects through drinking water have been neglected. The aim of this study was to investigate the potential in vivo alterations in the pulmonary tissue of male Sprague-Dawley rats after a 28-day oral exposure to copper (Cu), manganese (Mn) and mercury (Hg), alone and in mixtures, at 100 times the World Health Organization’s (WHO) safety limit for each heavy metal in drinking water. Forty-eight male Sprague-Dawley rats were randomly divided into eight groups (n = 6): control, Cu, Mn, Hg, Cu + Mn, Cu + Hg, Mn + Hg and Cu, Mn + Hg. The morphology of lung tissue and the bronchioles were evaluated using light- and transmission electron microscopy. For all exposed groups, morphological changes included thickened inter- and intra-alveolar spaces, stratified epithelium, disrupted smooth muscle and early fibrosis and desquamation of the epithelia of the bronchioles to varying degrees. In all exposed groups, ultrastructurally, an increase in disarranged collagen and elastin fibers, nuclear membrane detachment, chromatin condensation, indistinct nucleoli and an increase in collagen fiber disarrangement was observed. This study has identified that oral exposure to Cu, Mn and Hg and as part of mixtures caused pathogenesis due to inflammation, cellular damage and fibrosis with Mn + Hg being the most potent heavy metal group.

Mechanical modeling of the maturation process for textile reinforced tissue‐engineered heart valves

AbstractBiohybrid tissue‐engineered implants offer promising possibilities to treat cardiovascular diseases. The ability of tissue‐engineered implants to grow and remodel can be utilized to produce implants that can adapt to changes in the physiological conditions within the patient body. To improve the mechanical properties of the implant, a fibre‐reinforced textile scaffold is used. The embedment of a load‐oriented textile scaffold in the implant acts as biomimetic reinforcement and guides the direction of the extracellular matrix (ECM) growth. Our main objective is to design biohybrid heart valves that can withstand tough physiological loading conditions for decades. That makes it necessary to develop accurate and efficient models to support the design process.In this paper, the focus is on the macro‐mechanical modeling of the maturation process for textile reinforced heart valves. A biohybrid heart valve is modeled as a composite structure. The constitutive model is constructed by defining the total Helmholtz free energy as the sum of energies of the valve constituents. The two main constituents are (i) the extracellular matrix (ECM) and (ii) the fiber‐reinforced textile scaffold. The density of protein fibers such as collagen and elastin fibers are treated as internal variables. We introduce a new approach for modeling the densification of protein fibers during the cultivation process which is capable of considering both static and dynamic cultivation processes. The model considers the density change caused by the immunological response as well as the density change due to mechanical stimulation. The textile scaffold anisotropic behavior is introduced using structural tensors. The constitutive models are then embedded into a special finite element technology with reduced integration that enables efficient computations. The finite element simulation results are then validated using the experimental data provided by BioTex (Institute of Applied Medical Engineering, RWTH Aachen University, Germany). In the end, a finite element simulation for an exemplary valve is presented.

The multiscale characterization and constitutive modeling of healthy and type 2 diabetes mellitus Sprague Dawley rat skin.

In type 2 diabetes mellitus (T2DM), elevated glucose level impairs the biochemistry of the skin which may result in alteration of its mechanical and structural properties. The several aspects of structural and mechanical changes in skin due to T2DM remain poorly understood. To fill these research gaps, we developed a non-obese T2DM rat (Sprague Dawley (SD)) model for investigating the effect of T2DM on the in vivo strain stress state, mechanical and structural properties of skin. In vivo strain and mechanical anisotropy of healthy and T2DM skin were measured using the digital imaging correlation (DIC) technique and DIC coupled bulge experiment, respectively. Fluorescence microscopy and histology were used to assess the collagen and elastin fibers microstructure whereas nanoscale structure was captured through atomic force microscopy (AFM). Based on the microstructural observations, skin was modeled as a multilayer membrane where in and out of plane distribution of collagen fibers and planar distribution of elastin fibers were cast in constitutive model. Further, the state of in vivo stresses of healthy and T2DM were measured using model parameters and in vivo strain in the constitutive model. The results showed that T2DM causes significant loss in in vivo stresses (p < 0.01) and increase in anisotropy (p < 0.001) of skin. These changes were found in good correlation with T2DM associated alteration in skin microstructure. Statistical analysis emphasized that increase in blood glucose concentration (HbA1c) was the main cause of impaired biomechanical properties of skin. The presented data in this study can help to understand the skin pathology and to simulate the skin related clinical procedures. STATEMENT OF SIGNIFICANCE: Our study is significant as it presents findings related to the effect of T2DM on the physiologic stress strain, structural and mechanical response of SD rat skin. In this study, we developed a non-obese T2DM SD rat model which mimics the phenotype of Asian type 2 diabetics (non-obese). Several structural and mechanical characterization techniques were explored for multiscale characterization of healthy and T2DM skin. Further, based on microstructural information, we presented the constitutive models that incorporate the real microstructure of skin. The presented results can be helpful to simulate the realistic mechanical response of skin during various clinical trials.

LC-MS/MS analysis of elastin crosslinker desmosines and microscopic evaluation in clinical samples of patients with hypertrophy of ligamentum flavum

Ligamentum flavum (LF) pathologies often lead to severe myelopathy or radiculopathy characterized by reduced elasticity, obvious thickening, or worsened ossification. Elastin endows critical mechanical properties to tissues and organs such as vertebrae and ligaments. Desmosine (DES) and isodesmosine (IDES) are crosslinkers of elastin monomers called tropoelastin. These crosslinkers are potential biomarkers of chronic obstructive pulmonary disease. As a biological diagnostic tool that supplements existing symptomatic, magnetic resonance imaging scanning or radiological imaging diagnostic measures for LF hypertrophy and associated pathologies, an isotope-dilution liquid chromatography-tandem mass spectrometry method with selected reaction monitoring mode for the quantitation of DESs in human plasma, urine, cerebrospinal fluid (CSF), and yellow ligamentum was investigated. Isotopically labeled IDES-13C3,15N1 was used as an internal standard (ISTD) for DES quantitation for the first time. The samples plus ISTD were hydrolyzed with 6 N hydrochloric acid. Analytes and ISTD were extracted using a solid phase extraction cellulose cartridge column. The assays were repeatable, reproducible, and accurate with % CV ≤ 7.7, ISTD area % RSD of 7.6, and % AC ≤ (101.2 ± 3.90) of the calibrations. The ligamentum samples gave the highest average DES/IDES content (2.38 μg/mg) on a dry-weight basis. A high percentage of the CSF samples showed almost no DESs. Urine and plasma samples of patients showed no significant difference from the control (p-value = 0.0519 and 0.5707, respectively). Microscopy of the yellow ligamentum samples revealed dark or blue-colored zones of elastin fibers that retained the hematoxylin dye and highly red-colored zones of collagen after counterstaining with van Gieson solution. Thus, we successfully developed a method for DES/IDES quantitation in clinical samples.

Characterization of a novel rabbit model of Peyronie's disease.

Peyronie's disease (PD) is a debilitating pathology which is associated with penile curvature and erectile dysfunction due to the formation of fibrotic plaques in the penile tunica albuginea. In the present study, we developed a novel rabbit model of PD via subtunical injection of recombinant transforming growth factor (TGF)-β1 protein and characterized erectile function and histopathological endpoints following plaque formation. Ten adult male, New Zealand white rabbits were randomized into 3 experimental groups including nonsurgical controls (NSC, N = 3) and those receiving subtunical injections of vehicle (N = 3) or TGF-β1 protein (0.5 µg/50 µl; N = 4). Following 1 month post-op, focal fibrous plaques composed of disorganized collagen type I and III bundles as well as fragmented elastin fibers at TGF-β1 injection sites were observed in contrast to control groups. Cavernosometric and cavernosographic evaluations revealed no significant differences in maximum intracorporal pressures or substantial curvature during papaverine-induced erection in either the vehicle or TGF-β1 cohorts. Immunohistochemical and histomorphometric analyses demonstrated significant increases in elastase 2B expression in TGF-β1-induced plaques as well as significant declines in matrix metalloproteinase (MMP)-2 and -9 expression relative to control levels. Our results demonstrate that PD-like fibrotic plaques can be created in the rabbit penile tunica albuginea following TGF-β1 injection.

Murine model of elastase-induced proximal thoracic aortic aneurysm through a midline incision in the anterior neck.

This study was performed to develop a murine model of elastase-induced proximal thoracic aortic aneurysms (PTAAs). The ascending thoracic aorta and aortic arch of adult C57BL/6J male mice were exposed through a midline incision in the anterior neck, followed by peri-adventitial elastase or saline application. The maximal ascending thoracic aorta diameter was measured with high-resolution micro-ultrasound. Twenty-eight days after the operation, the aortas were harvested and analyzed by histopathological examination and qualitative polymerase chain reaction to determine the basic characteristics of the aneurysmal lesions. Fourteen days after the operation, the dilation rate (mean ± standard error) in the 10-min elastase application group (n = 10, 71.44 ± 10.45%) or 5-min application group (n = 9, 42.67 ± 3.72%) were significantly higher than that in the saline application group (n = 9, 7.37 ± 0.94%, P < 0.001 for both). Histopathological examination revealed aortic wall thickening, degradation of elastin fibers, loss of smooth muscle cells, more vasa vasorum, enhanced extracellular matrix degradation, augmented collagen synthesis, upregulated apoptosis and proliferation capacity of smooth muscle cells, and increased macrophages and CD4+ T cells infiltration in the PTAA lesions. Qualitative analyses indicated higher expression of the proinflammatory markers, matrix metalloproteinase-2 and -9 as well as Collagen III, Collagen I in the PTAAs than in the controls. We established a novel in vivo mouse model of PTAAs through a midline incision in the anterior neck by peri-adventitial application of elastase. This model may facilitate research into the pathogenesis of PTAA formation and the treatment strategy for this devastating disease.

Utilizing micro-CT imaging to define collagen modeling in murine aorta.

We aim to demonstrate local aortic tissue biodynamics via collagen and elastin fiber remodeling in murine aorta at varying distension using microcomputed tomography (microCT). Ten week-old C57BL/6 mice were injected via tail vein with in-vivo collagen hybridizing peptide, which reforms the triple-helix structure of denatured collagen, and is visualized via fluorescein tag. Careful dissection and removal of the thoracoabdominal aorta was performed, which was pressurized with formalin at varying distensions. Samples were then prepared via heavy-metal staining, and fixed in epoxy resin. These were subsequently imaged at the microCT scanner at University of Chicago, as well as at the 2-BM-B beamline using the Advanced Photon Source at Argonne National Laboratory to obtain micron and sub-micron resolution images and thus provide multi-level views of the tissue. Clear visualization of distinct collagen and elastin layers was observed with microCT. The images also clearly illustrate the effect on individual collagen and elastin fiber organization created by overdistension and shear-stress on the aorta. Clear demonstration of the geometric structure of aortic elastin fibers was seen upon initial segmentation. Preliminary experiments demonstrate that microCT provides an excellent visualization of murine aorta at micron and submicron levels. Next steps will be to segment and mesh this data in order to simulate local tissue responses to stress via finite element analysis. This method will produce a multi-scale imaging model of aortic failure.

Mapping the 3D remodeling of the extracellular matrix in human hypertrophic scar by multi-parametric multiphoton imaging using endogenous contrast

The hypertrophic scar is an aberrant form of wound healing process, whose clinical efficacy is limited by a lack of understanding of its pathophysiology. Remodeling of collagen and elastin fibers in the extracellular matrix (ECM) is closely associated with scar progression. Herein, we perform label-free multiphoton microscopy (MPM) of both fiber components from human skin specimens and propose a multi-fiber metrics (MFM) analysis model for mapping the structural remodeling of the ECM in hypertrophic scars in a highly-sensitive, three-dimensional (3D) manner. We find that both fiber components become wavier and more disorganized in scar tissues, while content accumulation is observed from elastin fibers only. The 3D MFM analysis can effectively distinguish normal and scar tissues with better than 95% in accuracy and 0.999 in the area under the curve value of the receiver operating characteristic curve. Further, unique organizational features with orderly alignment of both fibers are observed in scar-normal adjacent regions, and an optimized combination of features from 3D MFM analysis enables successful identification of all the boundaries. This imaging and analysis system uncovers the 3D architecture of the ECM in hypertrophic scars and exhibits great translational potential for evaluating scars in vivo and identifying individualized treatment targets.

Tricaprin can prevent the development of AAA by attenuating aortic degeneration

Medical therapeutic options to prevent rupture of abdominal aortic aneurysm (AAA), a critical event, must be developed. Moreover, further understanding of the process of AAA development and rupture is crucial. Previous studies have revealed that aortic hypoperfusion can induce the development of AAA, and we successfully developed a hypoperfusion-induced AAA animal model. In this study, we examined the effects of medium-chain triglycerides (MCTs), tricaprylin (C8-TG) and tricaprin (C10-TG), on hypoperfusion-induced AAA rat model. We estimated the effects of MCTs on aortic pathologies, mechanical properties of the aorta, and development of AAA. C10-TG, but not C8-TG, significantly suppressed AAA development and completely prevented the rupture. We observed that C10-TG prevented the development and rupture of AAA, but not C8-TG. Additionally, regression of AAA diameter was observed in the C10-TG group. Pathological analysis revealed C10-TG improved the hypoperfusion-induced increase in hypoxia-inducible factor-1α levels, medial smooth muscle cells (SMCs) loss, degeneration of aortic elastin and collagen fibers, and loss of aortic wall elasticity. In addition, regression of the formed AAA was observed by administration of C10-TG after AAA formation. C10-TG administration after AAA formation improved degeneration of AAA wall including degradation of aortic elastin and collagen fibers, stenosis of vasa vasorum, and loss of medial SMCs. These data suggest C10-TG can prevent AAA by attenuating aortic hypoperfusion and degeneration. Considering the clinical safety of C10-TG, C10-TG can be a promising AAA drug candidate.

DOP65 T-cell derived TGFβ1 remodels the rectum mesenchyme in Crohn’s Disease patients with perianal fistulizing disease

Abstract Background Perianal fistulizing disease (PFD) is a complication occurring in about 20% of Crohn’s Disease (CD) patients. It consists of the formation of new epithelised tracks connecting the intestine with the outer perianal region, which dramatically worsens a patient’s quality of life. The mechanisms driving fistula formation have not been elucidated and therefore, there are currently no specific treatments for PFD. Methods We collected rectum biopsies of CD patients with and without PFD in the absence of rectal inflammation (CD and CD+PFD), and with active rectal inflammation (CDinf and CD+PFDinf) (Fig.1). Rectal tissue samples were processed for RT-qPCR, or histologic analysis, and single-cell RNA sequencing (scRNAseq) for each patient. Results Differential expression gene (DEG) analysis of CD4+ and CD8+ T cells comparing CD vs CD+PFD and CDinf vs CD+PFDinf patients, respectively, revealed increased expression of TGFB1 in patients with fistulae. To investigate the main cellular subsets TGFB1 was interacting with, we performed ligand-receptor interaction analysis using CellphoneDB, which indicated that T-cell derived TGFB1 was primary interacting with the stromal compartment (Fig.2). 365 DEG were found in lamina propria (LP) fibroblasts of CD+PFD compared to CD, including TGFβ1-inducible genes such as TFPI2, SERPINE2 and MMPs 1 and 3. These changes were validated by bulk RT-qPCR, underscoring their potential use as PFD biomarkers (Fig.3). Moreover, we also identified a signature of elastin fibre assembly genes dysregulated in CD+PFD fibroblasts, suggesting molecular changes in the formation of elastin fibres in these patients. To determine whether the differentiation of fibroblasts was altered in the context of PFD, we conducted trajectory analysis using RNA velocity. Whilst fibroblasts in CD patients preferentially differentiate towards myofibroblasts, patients with PFD are biased towards LP fibroblasts, indicating an overall structural rearrangement of the mesenchyme in the rectum of patients with PFD, regardless of their inflammatory status (Fig.4). Importantly, analysis of an independent scRNAseq dataset of CD and ulcerative colitis (UC) patients showed higher expression of TGFB1 in T cells of active CD compared to active UC patients, suggesting that these alterations are already present in CD patients before the onset of a fistulizing phenotype and might potentially contribute to explain the absence of PFD in UC patients. Conclusion Based on these results, we suggest that the rectum of patients suffering from PFD present cellular and transcriptomic differences compared to CD patients without PFD. These changes are inflammation independent and point towards the TGFβ pathway as the main driver of this complication.

No differences in FBN1 genotype between men with and without abdominal aortic aneurysm

BackgroundAbdominal aortic aneurysm (AAA) is an aortic enlargement in which the transverse diameter reaches at least 30 mm. Certain risk factors, such as age, male gender, and smoking, are well known; however, less is known about the genetic factors involved. Fibrillin-1 (FBN1) is a protein that coordinates the deposition of elastin fibres in the extracellular matrix and is therefore likely to affect the elastic properties in the aortic wall. Previously studies have found associations between the FBN1-2/3 genotype and arterial stiffness, but how different FBN1 genotypes, AAA, and arterial stiffness are related has been less frequently investigated.AimThis study aimed to investigate whether there is a difference in FBN1 genotype between men with and without AAA. A further aim was to study whether the FBN1 genotype affects arterial wall stiffness differently in men with and without AAA.MethodsPulse wave velocity and FBN1 genotyping were performed in 229 men (159 with AAA, 70 without AAA). Participants were recruited from ultrasound AAA surveillance programs or ongoing ultrasound screening programs from 2011 to 2016.ResultsThe distribution of the FBN1 genotype in the AAA and control groups were as follows: FBN1-2/2: 62% vs. 64%; FBN1-2/3: 8% vs. 14%; and FBN1-2/4: 30% vs. 21%, respectively. Men with AAA and FBN1-2/2 had increased central pulse wave velocity (p < 0.005) compared to the control group (those without AAA) with the FBN1-2/2 genotype.ConclusionNo differences were found with respect to FBN1 genotypes between men with and without AAA. The development of AAA in men does not appear to be linked to a specific FBN1 genotype. Nevertheless, men with FBN1-2/2 and AAA have increased central arterial stiffness compared to men with the same FBN1 genotype but without AAA.

Avocado ( Persea americana Mill.) Seed Extract Cream 10% Inhibited The Increase MMP-12 Enzyme Levels And Elastosis In UVA Exposed Hairless Male Wistar Rats Skin

Background: Skin is the main target of environmental influences, especially chronic exposure to the suns UVA rays which will result in wrinkling, decreased skin elasticity, the appearance of loose skin, and a rough clinical appearance. In the dermal tissue, not only affects collagen fibers but also degradation of elastin fibers occurs through an increase in the MMP-12 enzyme levels called photoaging and is characterized by the accumulation of dystrophic elastin fibers throughout the dermal tissue in a process called Elastosis. Avocado seed (Persea americana Mill.) is a part of the fruit that contains high concentrations of flavonoids, phenols, and tannins, it has the potential as a powerful antioxidant. The aim of the present study is to evaluate the effectiveness of avocado (Persea americana Mill.) seed extract cream 10% inhibiting the increase in MMP-12 enzyme levels and elastosis in hairless male Wistar rats (Rattus norvegicus) which were exposed to ultraviolet A rays. Methods: A Randomized post-test-only control group design was conducted among 30 male Wistar rats for 10 consecutive days. They were divided into 3 groups as follows: group (K) as the negative control without any intervention, group (P1) with UVA rays exposure, and group (P2) with application of avocado (Persea americana Mill.) seed extraxt cream 10% and UVA rays exposure. The UVA dosage used is 5J/cm2 twice a day among P1 and P2 groups. Avocado (Persea americana Mill.) seed extract 10% was applied to the hairless Wistar rats 4 hours after the exposure of UVA rays. MMP-12 was calculated with Rat MMP-12 ELISA Test. Elastin fiber density was calculated by Imageraster software. Statistical analysis was carried out using SPSS version 25 in measure means, normality test, homogeneity test, and comparative test. Results: The results showed that the average MMP-12 enzyme level in the 10% avocado seed cream (P2) group 18.138 ± 0.168% was significantly different from the (K) group 1.073 ± 0.1553% as the negative control and the (P1) group 33.454 ± 1.068%. The mean density of elastin fiber in the cream of avocado seed extract group (P2) 12.42 ± 3.672% was significantly different from the group (K) 20.08 ± 4.994% and group (P1) 26.30 ± 6.822%. Comparative analysis using the Kruskal Wallis test for MMP-12 and the One Way Annova test for elastin fibers showed a p-value of < 0.05, thus indicating a significant difference between groups after treatment. The Least Significance Difference (LSD) test showed that there was a significant difference between the cream of avocado seed extract (P2) group and the other groups (p<0.05). Conclusions: The administration of avocado seeds (Persea americana Mill.) extract cream 10% effectively inhibits the increase in MMP-12 enzyme levels and elastosis in hairless male Wistar rat skin which was exposed to ultraviolet A irradiation.

CONTEMPORARY OPINIONS ON THE PECULIARITIES OF ORAL MUCOSA WOUNDS HEALING: A LITERATURE REVIEW

The purpose of the study is to update data on the features of oral mucosa (OM) wound healing through a systematic assessment of sources of scientific and medical information. Materials and Methods. An analysis of the data obtained during the information search in the online databases “PubMed”, “SciELO”, “Medscape”, and “Science of Ukraine: access to knowledge” was performed using the key words (tags): “mucous membrane of the oral cavity”, “oral mucosa”, “wounds of the mucous membrane”, “healing”, “regeneration”. Publications in periodical scientific issues, methodological recommendations, and reports were included in the list of sources of information. Results. According to the results of clinical observations, experimental studies on laboratory animals and volunteer patients, it was established that the healing of the OM wounds is qualitatively different from a similar process on the skin. This fact was established for both humans and animal models. Wound healing in the human body is a well-defined typical process aimed at restoring tissues after damage. Unlike the skin, OM wounds heal relatively quickly and with little or no scar tissue. And all this happens against the background of constant movement of soft tissues, stress (tension), mechanical abrasion, and contact with a large number of microorganisms in oral fluid. The leading factors of higher-quality regeneration of OM can be considered a moist wound healing environment, direct contact with the protective and regenerative systems of oral fluid which contains a high concentration of commensal microorganisms with immunomodulatory properties and more than 1000 protective and regulatory factors of saliva. There are distinct differences in the properties of the germ layer cells between the skin and OM and the cytokine profile of wound healing is also significantly different. Most reactions that take place in the main phases of the wound process in the oral cavity are faster and more intense. The processes of accumulation of collagen and elastin fibers, remodeling of the intercellular matrix (amorphous substance) are more qualitative. Conclusions: the data from the literature and the results of a significant number of studies allow us to state that faster wound closure, presence of saliva, faster immune response, increased release of anti-inflammatory cytokines, matrix metalloproteinase-mediated cleavage of chemokines, and remodeling of the extracellular matrix contribute to better wound healing and reduced scar formation on the OM, which, unfortunately, does not relate to the skin.

Biocompatible and bioactive hydrogels of recombinant fusion elastin with low transition temperature for improved healing of UV-irradiated skin.

Prolonged exposure to UV radiation can cause severe photodamage to the skin, leading to abnormal fragmentation of elastin fibers. As one of the main protein components of the dermal extracellular matrix, elastin plays a critical role in the mechanical behavior and physiological function of the skin. Animal-derived elastin has attracted extensive attention in tissue engineering, however it suffers from severe drawbacks such as a risk of virus transmission, ready degradation, and challenging quality control. Herein, we have for the first time developed a novel recombinant fusion elastin (RFE) and its cross-linked hydrogel for improved healing efficacy for UV-irradiated skin. RFE showed temperature-sensitive aggregation behavior similar to natural elastin. Compared with recombinant elastin without the fusion V-foldon domain, RFE showed a much more ordered secondary structure and lower transition temperature. Furthermore, Native-PAGE results indicated that the addition of the V-foldon domain triggered the formation of remarkable oligomers in RFE, which may result in a more ordered conformation. Tetrakis Hydroxymethyl Phosphonium Chloride (THPC) cross-linking of RFE led to the production of a fibrous hydrogel with uniform three-dimensional porous nanostructures and excellent mechanical strength. The RFE hydrogel showed superior cellular activity, significantly promoting the survival and proliferation of human foreskin fibroblast-1 (HFF-1). Studies of mice models of UV-irradiated skin demonstrated that the RFE hydrogel pronouncedly accelerated their healing process by inhibiting epidermal hyperplasia as well as boosting the regeneration of collagen and elastin fibers. The highly biocompatible and bioactive recombinant fusion elastin and its cross-linked hydrogel provide a potent treatment for photodamaged skin, which may have promising applications in dermatology and tissue engineering.

Elastin remodeling: Does it play a role in priming the malignant phenotype of oral mucosa?

The extracellular matrix (ECM) is a dynamic tissue that provides nutrition and support to overlying epithelium. During tumorigenesis, the tumor microenvironment (TME) dysregulates the ECM. This is reflected by morphological changes seen in collagen and elastic fibers and is thought to facilitate metastasis. To study the degradation of elastic fibers in different grades of oral squamous cell carcinoma (OSCC) and in oral epithelial dysplasia (OED) using histochemistry and to correlate it to the TNM stage of OSCC. Tumor cores from 38 cases of OSCC (well-differentiated[15], moderately differentiated[14], and poorly differentiated[9]) and 15 incisional biopsies of OED were analyzed. Hematoxylin-eosin and Verhoeff's-Van Gieson (VVG) stains were used. The stained sections were assessed for morphological changes in elastic fibers. Data were analyzed using Statistical Package for Social Sciences (SPSS) version 22 software. Fisher's exact, Kruskal-Wallis, one-way ANOVA, and Turkey post hoc tests were used to establish significance (P ≤ 0.05). Spearman's correlation test was used to correlate elastin fiber degradation with TNM stage of OSCC. All grades of OSCC showed absence of elastic fibers around the tumor islands. Elastic fiber degradation (fragmented and clumped type fibers) increased proportionately with the grade and TNM stage of OSCC. In OED, A significant reduction in the amount of elastic fibers with increasing grade was noted. A positive correlation was noted between elastin degradation and grade and stage of OSCC. Therefore, it may be implicated in tumor progression of OSCC.

Investigation of the link between the human skin relief and the dermal fibers network by coupling topographic analysis and LC-OCT imaging before and during folding tests

Knowing the evolution of the skin’s response to mechanical solicitations and understanding its origin is important in medicine, surgery, and cosmetics. Studies performed in vitro and ex vivo show that links exist between the topographic skin properties and the collagen and elastin fibers network in the dermis. But, to our knowledge, no in vivo study shows this link. In this study we propose a combination of experimental tests to demonstrate the link between the topographic skin properties and the fibers network in the dermis in vivo. The first method consists in analyzing the skin relief images. The second method uses a recently developed imaging technique of human skin in vivo with a high spatial resolution: Line-field Confocal Optical Coherence Tomography (LC-OCT). This technology provides two types of images modalities: vertical and horizontal section images. The skin relief images and its internal layers are carried out for the skin at rest and during a folding test. The latter is performed using a folding system developed in this study. From these images, we calculate the density of the skin lines printed on the skin surface and their orientations. Thanks to the two modalities of LC-OCT, we obtain the full 3D image of the skin volume. From these images we extract the fibers density and their orientation in the plans parallel and perpendicular to the outer skin surface. The study is carried out on 42 volunteers aged from 20 to 55 years-old. Skin relief analysis and LC-OCT images are performed on the skin of the forearm and thigh. The results show similar distributions of the skin lines on the surface and of its fibers in the volume. We could observe a correlation between the skin lines at the surface and the structure in depth of its layers in the volume (0.40 &lt; rSpearman &lt; 0.73).

Aging Skin and Anti-aging Strategies

The skin is a physical barrier that protects our body against various environmental, chemical and physical agents, and is the main organ that is easily visible as time progresses. Aging is a dynamic, progressive and undesirable biological process that unfortunately cannot be stopped, according to present knowledge. Intrinsic aging (chronological, spontaneous and biological aging) is a programmed natural process, while extrinsic aging (environmental aging and photoaging) is associated with sun exposure, smoking and malnutrition, which weakens the skin structure and functions. Over time, aging skin starts to lose elastin fibers, collagen and other proteins, which are the basic constituents that make skin healthy, bright, fit and elastic. There has been increasing interest in studies on various molecular and hormonal mechanisms, such as hormone dysfunction, changes in signaling pathways, the downregulation of mitochondrial function with cytokine increase, and mitochondrial DNA mutation. Antiaging treatment strategies can be divided into two parts: primary (basic) preventive antiaging approaches and secondary antiaging approaches after the phenotypic features of aging are revealed. The present study aims to review the literature information on the underlying causes of skin aging, healthy skin aging, and basic protective antiaging approaches. Understanding the extrinsic and intrinsic pathophysiological processes of aging would increase the effectiveness of future treatment-finding efforts.

The prospects of using apples and pears to obtain biologically active substances

Relevance. Apples and apple juices are healthy food products with a large amount of biologically active substances. The polyphenols contained in them are powerful natural antioxidants. They prevent the development of many chronic heart diseases and have many pharmacological properties. Thus, polyphenols increase the resistance of blood vessels, improve blood circulation, protect elastin and collagen fibers, and serve as fundamental elements supporting skin tissues. Apples contain such practically valuable substances as pectins. At the same time, in fresh apples, protopectin prevails over soluble pectin and makes up 52.3– 97.0% of the total amount.Methods. The objects of the study were the fruits of apple varieties: Voskhod, Talgar Bayterek, Sarkyt and Saya, as well as pear varieties: Bostandyk, Nagima, Sylyk, Zhazdyk. The fruits of apples and pears were harvested from September to mid-October 2021 in Saryagash district, in the farm "Tenge". Experimental data were obtained in the laboratory of the South-Kazakhstan University named after M. Auezov. At the first stage of the study, the quality of apples was determined in accordance with the requirements of GOST R 54697–2011. At the second stage, physico-chemical parameters were determined according to standard methods. The content of soluble solids was determined by the refractometric method using a refractometer, at ambient temperature 20±0.5 °C, The mass fraction of dry substances was determined by the refractive index. The sum of sugars — according to the Bertrand method.Result. Studies have established that the fruits of all studied varieties of apples and pears grown in Kazakhstan, according to organoleptic and physico-chemical indicators, contain high levels of chemicals and phenolic compounds, but the most valuable source of biologically active substances were apples of variety Baiterek and pears of variey Zhazdyk.