Terms Of Collagen Research Articles

Influence of surface engineering on 3D printed Ti lattice structure towards enhanced tissue integration: An in vitro and in vivo study

Reconstruction of segmental defects are popularly approached with surface engineered additively manufactured scaffolds owing to its enhanced post-surgery tissue integration properties. The present work is aimed at fabrication of Ti lattice structures using 3D printing, with a novel approach of silane chemistry-based surface modification of those Ti-surfaces with osteogenic peptides (OGP). The lattice structures with 0.6 mm strut-diameter having 0.5 mm inter-strut distance were chosen for fabrication using an extrusion-based 3D printing. Based on the evidence, it could be concluded that extrusion-based 3D printing is an optimal alternative as compared to those high cost incurring additive manufacturing processes. Therefore, OGP were grafted on the pristine Ti-surfaces using a silane chemistry based novel vapour deposition process. In vitro assessments of the surface modified scaffolds using human amniotic derived mesenchymal stem cells showed evidence of enhanced cell adhesion and viability. In vivo subcutaneous study in rat models of the surface modified Ti-scaffolds also showed enhanced tissue integration in terms of Collagen I deposition around the boundary of the tissue-integrated struts as compared to those of pristine scaffolds. The study has established that the novel surface modification technique is capable to engineer the Ti-surfaces towards enhanced tissue integration in vivo.

Enhanced Skin Permeation of Anti‐Aging Peptides Using Bioactive Ionic Liquids at Low Concentrations

AbstractDelaying aging is an eternal goal for humanity. Acetyl hexapeptide‐8 (AHP‐8) is an effective skin anti‐aging drug that locally interrupts the signal transmission of muscle contractions and promotes collagen production, thus smoothening wrinkles. However, its high molecular weight and strong hydrophilicity limit its skin permeation capacity. To solve this problem, an ionic liquid with excellent bioactivity, MAC, is synthesized from l‐malic acid and l‐carnitine and used as a permeation enhancer to improve the anti‐aging effects of AHP‐8. The ratio of MAC's components is optimized based on density functional theory calculations and cytotoxicity experiments. Low concentrations of MAC significantly increase AHP‐8 transdermal delivery, reaching a maximum at 5‐10 wt% MAC. The pro‐permeation mechanism of MAC is investigated using molecular dynamics simulations, and the penetration enhancement and anti‐aging performance of AHP‐8 are demonstrated by conducting cellular, animal, and clinical experiments. The results show that MAC/AHP‐8 outperforms AHP‐8 in terms of collagen and hyaluronic acid synthesis, anti‐inflammation, anti‐oxidation, and inhibition of muscle contraction, thus significantly reducing the number and area of wrinkles and increasing skin moisture and elasticity. This study presents MAC as a simple and efficient transdermal vehicle for the clinical application of AHP‐8.

Natural biopolymer scaffold for meniscus tissue engineering.

Meniscal injuries caused by trauma, degeneration, osteoarthritis, or other diseases always result in severe joint pain and motor dysfunction. Due to the unique anatomy of the human meniscus, the damaged meniscus lacks the ability to repair itself. Moreover, current clinical treatments for meniscal injuries, including meniscal suturing or resection, have significant limitations and drawbacks. With developments in tissue engineering, biopolymer scaffolds have shown promise in meniscal injury repair. They act as templates for tissue repair and regeneration, interacting with surrounding cells and providing structural support for newly formed meniscal tissue. Biomaterials offer tremendous advantages in terms of biocompatibility, bioactivity, and modifiable mechanical and degradation kinetics. In this study, the preparation and composition of meniscal biopolymer scaffolds, as well as their properties, are summarized. The current status of research and future research prospects for meniscal biopolymer scaffolds are reviewed in terms of collagen, silk, hyaluronic acid, chitosan, and extracellular matrix (ECM) materials. Overall, such a comprehensive summary provides constructive suggestions for the development of meniscal biopolymer scaffolds in tissue engineering.

The deep fascia and its role in chronic pain and pathological conditions: A review.

The deep fascia is a three-dimensional continuum of connective tissue surrounding the bones, muscles, nerves and blood vessels throughout our body. Its importance in chronically debilitating conditions has recently been brought to light. This work investigates changes in these tissues in pathological settings. A state-of-the-art review was conducted in PubMed and Google Scholar following a two-stage process. A first search was performed to identify main types of deep fasciae. A second search was performed to identify studies considering a deep fascia, common pathologies of this deep fascia and the associated alterations in tissue anatomy. We find that five main deep fasciae pathologies are chronic low back pain, chronic neck pain, Dupuytren's disease, plantar fasciitis and iliotibial band syndrome. The corresponding fasciae are respectively the thoracolumbar fascia, the cervical fascia, the palmar fascia, the plantar fascia and the iliotibial tract. Pathological fascia is characterized by increased tissue stiffness along with alterations in myofibroblast activity and the extra-cellular matrix, both in terms of collagen and Matrix Metalloproteases (MMP) levels. Innervation changes such as increased density and sensitization of nociceptive nerve fibers are observed. Additionally, markers of inflammation such as pro-inflammatory cytokines and immune cells are documented. Pain originating from the deep fascia likely results from a combination of increased nerve density, sensitization and chronic nociceptive stimulation, whether physical or chemical. The pathological fascia is characterized by changes in innervation, immunology and tissue contracture. Further investigation is required to best benefit both research opportunities and patient care.

Inactivated Nevus Tissue with High Hydrostatic Pressure Treatment Used as a Dermal Substitute after a 28-Day Cryopreservation Period.

Background Giant congenital melanocytic nevi (GCMN) treatment remains controversial. While surgical resection is the best option for complete removal, skin shortage to reconstruct the skin defect remains an issue. We report a novel treatment using a high hydrostatic pressurization (HHP) technique and a cryopreservation procedure. However, cryopreservation may inhibit revascularization of implanted nevus tissue and cultured epidermal autograft (CEA) take. We aimed to investigate the influence of the cryopreservation procedure on the HHP-treated dermis specimen and CEA take on cryopreserved tissue. Methods Nevus tissue harvested from a patient with GCMN was inactivated with HHP of 200 MPa and then cryopreserved at -30°C for 28 days. The cryopreserved specimen was compared with fresh (HHP-treated without cryopreservation) tissue and with untreated (without HHP treatment) tissue to evaluate the extracellular matrix, basal membranes, and capillaries. Cultured epidermis (CE) take on the cryopreserved tissue was evaluated following implantation of the cryopreserved nevus tissue with CE into the subcutis of nude mice. Results No difference was observed between cryopreserved and fresh tissue in terms of collagen or elastic fibers, dermal capillaries, or basement membranes at the epidermal-dermal junction. In 4 of 6 samples (67%), applied CE took on the nevus tissues and regenerated the epidermis in the cryopreserved group compared with 5 of 6 samples (83%) in the fresh group. Conclusion Cryopreservation at -30°C for 28 days did not result in significant damage to inactivated nevus tissue, and applied CE on the cryopreserved nevus tissues took and regenerated the epidermis. Inactivated nevus tissue with HHP can be used as a dermal substitute after 28-day cryopreservation.

PCL/collagen blends prepared by solution blow spinning as potential materials for skin regeneration

AbstractSolution blow spinning (SBS), is used to prepare biocompatible fibrous materials based on poly‐ε‐caprolactone (PCL), modified with collagen. Materials with different compositions in terms of collagen are prepared. Structure, morphology, topography, wettability behavior, and cytotoxicity are studied in order to investigate the potentiality of these materials for medical applications in the field of tissue repairing and regeneration. Structure is studied by Fourier transformed infrared spectroscopy, morphology by scanning electron microscopy, topography by optical profilometry and wettability behavior by contact angle measurements. The addition of small amounts of collagen to PCL by SBS can induce important variations in the morphology and topography of the materials that, in turns, lead to changes in the wettability behavior and ability ofHaCatcells adhesion and proliferation. The analysis of surface characteristics together with the use of a model based on mats constituted by cylinders disposed perpendicularly to each other point out that, under the compositions considered, the main factor leading to higher adhesion and proliferation of cells on the PCL/collagen is the presence of more available surface area.

A microstructure-based model for time-dependent mechanics of multi-layered soft tissues and its application to intervertebral disc annulus

In recent experimental studies an unusual time-dependent transversal behavior of the annulus fibrosus of the intervertebral disc mainly caused by the coupling between mechanics and electro-chemical activity was disclosed. In this contribution, a microstructure-based model is proposed to connect structural features, intrinsic mechanics and electro-chemical properties of multi-layered soft tissues with a special attention to disc annulus. A hybrid experimental/modeling decoupling strategy is proposed to obtain the constitutive representation of each layer of the disc annulus thanks to full-field strain data. The layers are then reconnected to each other to get the overall time-dependent response considering inter-layer ionic diffusion as well as stress/strain continuity along the interfaces. The final constitutive model is shown to describe the experimentally observed behavior of bovine tissues under free swelling immediately followed by quasi-static stretching, deviating from chemical equilibrium and provoking auxeticity, and then relaxation, allowing equilibrium return. The model/experiments comparison demonstrates that the evaluation of the overall time-dependent response involves considering stress, volumetric change and auxetic feature simultaneously in relation to diffusion-mechanics and structural features in terms of collagen orientation/content, interlamellar matrix inter-spacing fiber-reinforced layers and gradual thickness of layers. The effective contribution of fiber-reinforced and unreinforced interlamellar layers on the coupling is discussed with respect to the model. Using the model, microstructure and coupling effects are independently investigated in order to highlight their role on the damage-related annulus shearing.

Regional collagen turnover and composition of the human patellar tendon.

Tendon pathology (tendinopathy) typically occurs in specific regions of a tendon, and growth in response to exercise also appears to be more pronounced in specific regions. In a previous study in animals we found evidence of regional differences in tendon turnover, but whether the turnover of human patellar tendon differs in different regions still remains unknown. Patellar tendons were obtained from cadavers of healthy men and women (body donation program, n = 5 donors, >60 yr of age). Samples were taken from 10 different regions along the length, width, and thickness of the tendon. Turnover was measured by 14C bomb pulse dating and also estimated from the accumulation of advanced glycation end products (AGEs) by fluorescence (340/460 nm) in addition to measurement of specific AGEs by mass spectrometry. Composition in terms of collagen, glycosaminoglycans (GAGs), and DNA was also assessed in each region. 14C results showed that all tendon regions had a similar 14C concentration, which was equal to the average atmospheric 14C concentration during the first 15 yr of the person's life. Fluorescence normalized to dry weight did not differ between regions, nor did specific AGEs. Higher GAG content was observed in the proximal and near the distal insertion of the tendon. In conclusion, healthy human patellar tendon displays no regional differences in collagen turnover throughout life.NEW & NOTEWORTHY Tendon injuries and tendinopathies typically occur in specific regions of the tendon, but the reason for this specificity is not well understood. A potential factor in injury susceptibility is tissue turnover, and previous work suggests that the tendon core has practically no turnover during adult life; however, it is not known whether this is true for other regions of the tendon. Our present results on healthy human patellar tendon clearly demonstrate that turnover does not differ between regions and thereby cannot explain differences in injury susceptibility. The findings also indicate that all regions of the tendon are formed simultaneously during skeletal maturation and do not turn over appreciably during adulthood. This is an important finding because little is known about tendon growth during maturation in humans.

Biocompatibility of Ionomeric Cements Modified by Red Propolis: A Morphological and Immunohistochemical Analysis.

To evaluate the biocompatibility in rat subcutaneous tissue of conventional orthodontic cements, Riva (R) and Meron (M), modified by the addition of ethanolic extract of red propolis (EERP), at different concentrations and time intervals. One hundred eight male adult Wistar rats were used, distributed in nine groups of cements with added EERP at the concentrations used (C-control, MC, M10, M25, M50, RC, R10, R25, and R50). The rats were sacrificed after 3 time intervals (7, 15, and 30 days). Histological and immunohistochemical analyses were performed. The findings were statistically analyzed using the Kruskal-Wallis test followed by Dunn's test (p < 0.05). The highest concentrations led to a higher level of inflammation at the initial times (p < 0.05), but without differences after 30 days. In terms of collagen, there was less collagenization at the initial times in comparison with the control group C. However, over time, the addition of propolis resulted in healing compatible with that of group C. The level of CD68 immunostaining was statistically significantly higher in the groups with the highest concentrations (R50 and M50) (p = 0.001). Orthodontic cements with the addition of EERP were found to be biocompatible in rat subcutaneous tissue. Riva cement with the addition of 50% EERP showed the highest tissue inflammation, but with satisfactory tissue repair.

Electromechanical-Conductive Natural Rubber Doped Eggshell and Eggshell Membrane for Drug Delivery and Actuator Applications

Natural rubber composite materials were prepared by using sulfur curing system of STR 5L added with hen eggshell and eggshell membrane to increase electrical and mechanical properties for biomimetic actuator and artificial muscle applications. Samples were vulcanized at temperature 150°C. Hen eggshells and eggshell membrane powder (0, 20, 40, and 60 phr) were added into natural rubber. The main composition of hen eggshells composed of 96.35 wt% calcium carbonate (CaCO3) while mostly composition of hen eggshell membrane is fibrous protein in terms of collagen. The best condition is addition of eggshell 40 phr (formula 3) and eggshell membrane 20 phr (formula 5) to obtain the highest storage modulus response equal to 2.85 x 106 and 2.97 x106 Pa, respectively. The curing time (Tc90) of pure natural rubber (formula 1), formula 3, and formula 5 are 8.22, 6.73, and 5.67 min, respectively. Furthermore, the curing time, rheology, and electrical field response of natural rubber composite materials were measured by moving die rheometer and impedance analyzer, and reported here.

ELECTROMECHANICAL-CONDUCTIVE NATURAL RUBBER DOPED EGGSHELL AND EGGSHELL MEMBRANE FOR DRUG DELIVERY AND ACTUATOR APPLICATIONS

Natural rubber composite materials were prepared from vulcanization STR 5L in sulfur curing system by being added with eggshell and eggshell membrane in order to increase electrical and mechanical properties for biomimetic actuator and artificial muscle applications. Samples were vulcanized at temperature 150°C. Hen eggshells and eggshell membrane powder (0, 20, 40, and 60 phr) were added in natural rubber. The main composition of eggshells is calcium carbonate (CaCO 3 ) of high purity more than 96.35 wt% whereas the main composition of eggshell membrane is fibrous protein in terms of collagen. The best condition is addition of eggshell 40 phr (formula 3) and eggshell membrane 20 phr (formula 5) to obtain the highest storage modulus response equal to 2.85 x 10 6 and 2.97 x10 6 Pa, respectively. The curing time (Tc 90 ) of pure natural rubber (formula 1), formula 3, and formula 5 are 8.22, 6.73, and 5.67 min, respectively. Furthermore, the curing time, rheology, and electric field response of natural rubber composite materials are investigate by moving die rheometer and compression set , and the results are reported here.

A novel engineered dermis for in vitro photodamage research.

The realization of biologically relevant human tissue equivalents as an in vitro model to investigate human diseases, as well as to test the efficacy or toxicity of novel compounds, is emerging as a new challenge in tissue engineering. Currently, the in vitro three-dimensional (3D) dermis model mainly involves the use of cells embedded in exogenous non-human matrices. However, such models feature biological and functional disparities with native dermis, therefore limiting their relevance to the in vivo situation. The purpose of this study was to provide a reliable endogenous human dermal equivalent (HDE) able to recapitulate the extracellular matrix (ECM) remodelling of the native dermis occurring after external damage. To this end, UVA irradiation was used to induce photodamage to both the HDE and to a fibroblast-populated collagen matrix. The photodamage was investigated at the cellular and ECM level and the results showed that, although a cellular response was detected in both systems, no ECM reorganization characteristic of the in vivo photo-aged dermis could be detected in the fibroblast-populated collagen matrix. In contrast in the HDE, the neosynthesized ECM recapitulated the characteristic ageing behaviour of the dermis found in vivo, in terms of collagen and hyaluronic acid synthesis as well as collagen organization remodelling. This study therefore demonstrates the role of the endogenous ECM in recapitulating in vitro the functionality of the human dermis and the proposed HDE as a novel tool for photoprotection trials. Copyright © 2016 John Wiley & Sons, Ltd.

Expression Collagen I and III in Anterior Vaginal Women with and without Pelvic Organ Prolapse

Objective: To find out the expression of collagen [ and III in the anterior vaginal wall of women with and without pelvic organ prolapse (POP).&#x0D; Method: The research was a cross sect ional study, conducted in Dr. Wahidin Sudiro Husodo hospital and its networks from January 1, 2011 to April 1, 2012. The case group consisted of 35 women with POPlevel III and IV.The contro l group consisted of35 women without POP. The expression of collagen I and III were examined by immunohistochemical test with the stain ing of antibody of collagen I (mouse monoclonal collagen lab 90395 ) and the antibody collagen III (Mu167 4i).The data was then analyzed by using a computer statistic program with a significance level of 0.05.&#x0D; Result: It was found that in the group of women with POP, there were 28 cases of expression collagen III (84%), which is significantly higher than in women without POP, found in only 20 cases (58.8%), with p=0.02. Meanwhile, in the group of POP, 9.1% of subjects showed moderate expre ssion of collagen I, significantly less compared to the expressio n in the contro l group (35.3%), with p=0.007. For the ratio of collagen I and III, the result was weak in women with POP(58.5% ) while in the control group, the result was high (85.7%).&#x0D; Conclu sion: In terms of collagen I and III expression, there was no significant difference between the two groups.&#x0D; Keywords: collagen I, collagen III, pelvic organ prolapse, vaginal wall

Comparison of Chondrocytes Produced from Adipose Tissue–Derived Stem Cells and Cartilage Tissue

Spontaneous cartilage regeneration is poor after a cartilage defect occurs by trauma, surgical, and other reasons. Importance of producing chondrocytes from stem cells and using tissues to repair a defect is getting popular. The aim of this study was to compare the effects of injectable cartilage produced by chondrocytes differentiated from adipose tissue-derived mesenchymal stem cells and chondrocyte cells isolated directly from cartilage tissue. Mesenchymal stem cells were isolated from rat adipose tissue and characterized by cell-surface markers. Then, they were differentiated to chondrocyte cells. The function of differentiated chondrocyte cells was compared with chondrocyte cells directly isolated from cartilage tissue in terms of collagen and glycosaminoglycan secretion. Then, both chondrocyte cell types were injected to rats' left ears in liquid and gel form, and histologic evaluation was done 3 weeks after the injection. Adipose-derived stem cells were strongly positive for the CD44 and CD73 mesenchymal markers. Differentiated chondrocyte cells and chondrocyte cells directly isolated from cartilage tissue had relative collagen and glycosaminoglycan secretion results. However, histologic evaluations did not show any cartilage formation after both chondrocyte cell types were injected to rats. Strong CD44- and CD73-positive expression indicated that adipose-derived cells had the stem cell characters. Collagen and glycosaminoglycan secretion results demonstrated that adipose-derived stem cells were successfully differentiated to chondrocyte cells.

Effect of pancreatectomy, with and without hypophysectomy, and of insulin treatment on the composition of canine aorta.

The chemical composition of aorta from normal and endocrine deficient dogs was studied in terms of collagen, elastin, calcium, “water plus lipid” and mucopolysaccharide (MPS) content. The latter component was resolved into four fractions: hyaluronic acid (HA), heparan sulfate (HS), dermatan sulfate (DS), and the isomeric chondroitin sulfates (CS). The results were compared in the following way: (1) normal versus pancreatectomized; (2) hypophysectomized versus hypophysectomized and pancreatectomized (Houssay); and (3) Houssay with and without insulin treatment. Pancreatectomy affected the content of two constituents only: the HS and CS levels were lowered. The low content could be raised by insulin treatment. These results indicate that except for the sulfated MPS, insulin does not appreciably alter the composition of the aortic wall.