Displaying publications 21 - 40 of 277 in total

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  1. Recent Development in the Fabrication of Collagen Scaffolds for Tissue Engineering Applications: A Review
    Busra MFM, Lokanathan Y
    Curr Pharm Biotechnol, 2019;20(12):992-1003.
    PMID: 31364511 DOI: 10.2174/1389201020666190731121016
    Tissue engineering focuses on developing biological substitutes to restore, maintain or improve tissue functions. The three main components of its application are scaffold, cell and growthstimulating signals. Scaffolds composed of biomaterials mainly function as the structural support for ex vivo cells to attach and proliferate. They also provide physical, mechanical and biochemical cues for the differentiation of cells before transferring to the in vivo site. Collagen has been long used in various clinical applications, including drug delivery. The wide usage of collagen in the clinical field can be attributed to its abundance in nature, biocompatibility, low antigenicity and biodegradability. In addition, the high tensile strength and fibril-forming ability of collagen enable its fabrication into various forms, such as sheet/membrane, sponge, hydrogel, beads, nanofibre and nanoparticle, and as a coating material. The wide option of fabrication technology together with the excellent biological and physicochemical characteristics of collagen has stimulated the use of collagen scaffolds in various tissue engineering applications. This review describes the fabrication methods used to produce various forms of scaffolds used in tissue engineering applications.
    Matched MeSH terms: Collagen/chemistry*
  2. Fulltext Mechanical Strain-Mediated Tenogenic Differentiation of Mesenchymal Stromal Cells Is Regulated through Epithelial Sodium Channels
    Nam HY, Murali MR, Ahmad RE, Pingguan-Murphy B, Raghavendran HRB, Kamarul T
    Stem Cells Int, 2020;2020:5385960.
    PMID: 32908542 DOI: 10.1155/2020/5385960
    It has been suggested that mechanical strain may elicit cell differentiation in adult somatic cells through activation of epithelial sodium channels (ENaC). However, such phenomenon has not been previously demonstrated in mesenchymal stromal cells (MSCs). The present study was thus conducted to investigate the role of ENaC in human bone marrow-derived MSCs (hMSCs) tenogenic differentiation during uniaxial tensile loading. Passaged-2 hMSCs were seeded onto silicone chambers coated with collagen I and subjected to stretching at 1 Hz frequency and 8% strain for 6, 24, 48, and 72 hours. Analyses at these time points included cell morphology and alignment observation, immunocytochemistry and immunofluorescence staining (collagen I, collagen III, fibronectin, and N-cadherin), and gene expression (ENaC subunits, and tenogenic markers). Unstrained cells at similar time points served as the control group. To demonstrate the involvement of ENaC in the differentiation process, an ENaC blocker (benzamil) was used and the results were compared to the noninhibited hMSCs. ENaC subunits' (α, β, γ, and δ) expression was observed in hMSCs, although only α subunit was significantly increased during stretching. An increase in tenogenic genes' (collagen1, collagen3, decorin, tenascin-c, scleraxis, and tenomodulin) and proteins' (collagen I, collagen III, fibronectin, and N-cadherin) expression suggests that hMSCs underwent tenogenic differentiation when subjected to uniaxial loading. Inhibition of ENaC function resulted in decreased expression of these markers, thereby suggesting that ENaC plays a vital role in tenogenic differentiation of hMSCs during mechanical loading.
    Matched MeSH terms: Collagen; Collagen Type I
  3. Fulltext The immunohistochemical and urodynamic evaluation towards the collagen-coated and non-coated polypropylene meshes implanted in the pelvic wall of the rats
    Lo TS, Lin YH, Yusoff FM, Chu HC, Hsieh WC, Uy-Patrimonio MC
    Sci Rep, 2016 12 19;6:38960.
    PMID: 27991501 DOI: 10.1038/srep38960
    Our aim is to study the inflammatory response towards the collagen-coated and non-coated polypropylene meshes in rats and the urodynamic investigation post-operatively. Forty-two female Sprague Dawley were divided into 7 groups of 6 rats; Control, Day 7 and 30 for Sham, Avaulta Plus (MPC), Perigee (MP). UDS were taken at days 7 and 30. Mesh with the vagina and bladder wall was removed and sent for immunohistochemical examination. Results showed intense inflammatory reaction on day 7 in the study groups which decreased on day 30. IL-1, TNF-α, MMP-2 and CD31 were observed to decrease from day 7 to day 30. NGF was almost normal on day 30 in all groups. UDS showed no difference in voiding pressure. Both Study and Sham groups had shorter voiding interval (VI) on day 7 but significantly lower in MPC. VI had significantly increased on day 30 in all groups. Voided volume was significantly lower in the mesh groups even when an increase was seen on day 30. In conclusion, the higher levels of IL-1, TNF-α and MMP-2 in collagen-coated polypropylene mesh imply greater inflammation than the non-coated polypropylene mesh. Mesh implantation can lead to shorter voiding interval and smaller bladder capacity.
    Matched MeSH terms: Collagen*
  4. In Vitro Evaluation of Human Hand Tendon Ingrowth into A Synthetic Scaffold
    Abdullah S, Mohtar F, Abdul Shukor N, Sapuan J
    J Hand Surg Asian Pac Vol, 2017 Dec;22(4):429-434.
    PMID: 29117830 DOI: 10.1142/S0218810417500459
    BACKGROUND: Synthetic scaffold has been used for tissue approximation and reconstructing damaged and torn ligaments. This study explores the ability of tendon ingrowth into a synthetic scaffold in vitro, evaluate growth characteristics, morphology and deposition of collagen matrix into a synthetic scaffold.

    METHODS: Upper limb tendons were harvested with consent from patients with crush injuries and non-replantable amputations. These tendons (both extensor and flexor) measuring 1 cm are sutured to either side of a 0.5 cm synthetic tendon strip and cultured in growth medium. At 2, 4, 6 and 8 weeks, samples were fixed into paraffin blocks, cut and stained with haematoxylin-eosin (H&E) and Masson's trichrome.

    RESULTS: Minimal tendon ingrowth were seen in the first 2 weeks of incubation. However at 4 weeks, the cell ingrowth were seen migrating towards the junction between the tendon and the synthetic scaffold. This ingrowth continued to expand at 6 weeks and up to 8 weeks. At this point, the demarcation between human tendon and synthetic scaffold was indistinct.

    CONCLUSIONS: We conclude that tendon ingrowth composed of collagen matrix were able to proliferate into a synthetic scaffold in vitro.

    Matched MeSH terms: Collagen/analysis
  5. Liver Extracellular Matrix-Based Nanofiber Scaffolds for the Culture of Primary Hepatocytes and Drug Screening
    Vasudevan A, Majumder N, Sharma I, Kaur I, Sundarrajan S, Venugopal JR, et al.
    ACS Biomater Sci Eng, 2023 Nov 13;9(11):6357-6368.
    PMID: 37847169 DOI: 10.1021/acsbiomaterials.3c01216
    Immortalized liver cell lines and primary hepatocytes are currently used as in vitro models for hepatotoxic drug screening. However, a decline in the viability and functionality of hepatocytes with time is an important limitation of these culture models. Advancements in tissue engineering techniques have allowed us to overcome this challenge by designing suitable scaffolds for maintaining viable and functional primary hepatocytes for a longer period of time in culture. In the current study, we fabricated liver-specific nanofiber scaffolds with polylactic acid (PLA) along with a decellularized liver extracellular matrix (LEM) by the electrospinning technique. The fabricated hybrid PLA-LEM scaffolds were more hydrophilic and had better swelling properties than the PLA scaffolds. The hybrid scaffolds had a pore size of 38 ± 8 μm and supported primary rat hepatocyte cultures for 10 days. Increased viability (2-fold increase in the number of live cells) and functionality (5-fold increase in albumin secretion) were observed in primary hepatocytes cultured on the PLA-LEM scaffolds as compared to those on conventional collagen-coated plates on day 10 of culture. A significant increase in CYP1A2 enzyme activity was observed in hepatocytes cultured on PLA-LEM hybrid scaffolds in comparison to those on collagen upon induction with phenobarbital. Drugs like acetaminophen and rifampicin showed the highest toxicity in hepatocytes cultured on hybrid scaffolds. Also, the lethal dose of these drugs in rodents was accurately predicted as 1.6 g/kg and 594 mg/kg, respectively, from the corresponding IC50 values obtained from drug-treated hepatocytes on hybrid scaffolds. Thus, the fabricated liver-specific electrospun scaffolds maintained primary hepatocyte viability and functionality for an extended period in culture and served as an effective ex vivo drug screening platform to predict an accurate in vivo drug-induced hepatotoxicity.
    Matched MeSH terms: Collagen/metabolism
  6. Genotoxicity and cytotoxicity of ovine collagen on human dermal fibroblasts
    Busra FM, Chowdhury SR, Saim AB, Idrus RB
    Saudi Med J, 2011 Dec;32(12):1311-2.
    PMID: 22159390
    Matched MeSH terms: Collagen/toxicity*
  7. Fulltext Collagen-related genes influence the glaucoma risk factor, central corneal thickness
    Vithana EN, Aung T, Khor CC, Cornes BK, Tay WT, Sim X, et al.
    Hum Mol Genet, 2011 Feb 15;20(4):649-58.
    PMID: 21098505 DOI: 10.1093/hmg/ddq511
    Central corneal thickness (CCT) is a risk factor of glaucoma, the most common cause of irreversible blindness worldwide. The identification of genetic determinants affecting CCT in the normal population will provide insights into the mechanisms underlying the association between CCT and glaucoma, as well as the pathogenesis of glaucoma itself. We conducted two genome-wide association studies for CCT in 5080 individuals drawn from two ethnic populations in Singapore (2538 Indian and 2542 Malays) and identified novel genetic loci significantly associated with CCT (COL8A2 rs96067, p(meta) = 5.40 × 10⁻¹³, interval of RXRA-COL5A1 rs1536478, p(meta) = 3.05 × 10⁻⁹). We confirmed the involvement of a previously reported gene for CCT and brittle cornea syndrome (ZNF469) [rs9938149 (p(meta) = 1.63 × 10⁻¹⁶) and rs12447690 (p(meta) = 1.92 × 10⁻¹⁴)]. Evidence of association exceeding the formal threshold for genome-wide significance was observed at rs7044529, an SNP located within COL5A1 when data from this study (n = 5080, P = 0.0012) were considered together with all published data (reflecting an additional 7349 individuals, p(Fisher) = 1.5 × 10⁻⁹). These findings implicate the involvement of collagen genes influencing CCT and thus, possibly the pathogenesis of glaucoma.
    Matched MeSH terms: Collagen/genetics*; Collagen Type VIII/genetics
  8. Fulltext Common laboratory tests for rheumatological disorders: how do they help the diagnosis?
    Das Gupta E
    Malays Fam Physician, 2009;4(2-3):48-50.
    PMID: 25606162 MyJurnal
    No screening test is ideal for detecting rheumatic diseases; diagnosis depends on appropriate history and thorough physical examination. Sometimes, laboratory investigations may be useful in confirming or ruling out rheumatic disease after a clinical diagnosis is considered. Once a rheumatic disease has been diagnosed, certain laboratory tests can help in assessing prognosis or determining the extent of the disease. Laboratory tests may also help the physician monitor certain rheumatic diseases, guide treatment or assess potential drug toxicity.
    Matched MeSH terms: Collagen Diseases
  9. Fulltext Current Insight of Collagen Biomatrix for Gingival Recession: An Evidence-Based Systematic Review
    Naomi R, Ardhani R, Hafiyyah OA, Fauzi MB
    Polymers (Basel), 2020 Sep 13;12(9).
    PMID: 32933133 DOI: 10.3390/polym12092081
    Collagen (Col) is a naturally available material and is widely used in the tissue engineering and medical field owing to its high biocompatibility and malleability. Promising results on the use of Col were observed in the periodontal application and many attempts have been carried out to inculcate Col for gingival recession (GR). Col is found to be an excellent provisional bioscaffold for the current treatment in GR. Therefore, the aim of this paper is to scrutinize an overview of the reported Col effect focusing on in vitro, in vivo, and clinical trials in GR application. A comprehensive literature search was performed using EBSCOhost, Science Direct, Springer Link, and Medline & Ovid databases to identify the potential articles on particular topics. The search query was accomplished based on the Boolean operators involving keywords such as (1) collagen OR scaffold OR hybrid scaffold OR biomaterial AND (2) gingiva recession OR tissue regeneration OR dental tissue OR healing mechanism OR gingiva. Only articles published from 2015 onwards were selected for further analysis. This review includes the physicochemical properties of Col scaffold and the outcome for GR. The comprehensive literature search retrieved a total of 3077 articles using the appropriate keywords. However, on the basis of the inclusion and exclusion criteria, only 15 articles were chosen for further review. The results from these articles indicated that Col promoted gingival tissue regeneration for GR healing. Therefore, this systematic review recapitulated that Col enhances regeneration of gingival tissue either through a slow or rapid process with no sign of cytotoxicity or adverse effect.
    Matched MeSH terms: Collagen
  10. Extraction, anti-tyrosinase, and antioxidant activities of the collagen hydrolysate derived from Rhopilema hispidum
    Ab Aziz NA, Salim N, Zarei M, Saari N, Yusoff FM
    Prep Biochem Biotechnol, 2021;51(1):44-53.
    PMID: 32701046 DOI: 10.1080/10826068.2020.1789991
    The study was conducted to determine anti-tyrosinase and antioxidant activities of the extracted collagen hydrolysate (CH) derived from Malaysian jellyfish, Rhopilema hispidum. Collagen was extracted using 1:1 (w:v) 0.1 M NaOH solution at temperature 25 °C for 48 hr followed by treatment of 1:2 (w:v) distilled water for another 24 hr and freeze-dried. The extracted collagen was hydrolyzed using papain at optimum temperature, pH and enzyme/substrate ratio [E/S] of 60 °C, 7.0 and 1:50, respectively. CH was found to exhibit tyrosinase inhibitory activity, DPPH radical scavenging and metal ion-chelating assays up to 64, 28, and 83%, respectively, after 8 hr of hydrolysis process. The molecular weight of CH was found <10 kDa consisting of mainly Gly (19.219%), Glu (10.428%), and Arg (8.848%). The UV-visible spectrum analysis showed a major and minor peak at 218 and 276 nm, accordingly. The FTIR spectroscopy confirmed the amide groups in CH. The SEM images demonstrated spongy and porous structure of CH. In the cytotoxicity study, CH has no cytotoxicity against mouse embryonic 3T3 fibroblast cell line with IC50 value >500 µg/ml. Results revealed that the CH generated from this study has a potential to be developed as active ingredient in cosmeceutical application.
    Matched MeSH terms: Collagen/isolation & purification*; Collagen/pharmacology*; Collagen/chemistry
  11. Fulltext Molecular Mechanisms of Stress-Responsive Changes in Collagen and Elastin Networks in Skin
    Aziz J, Shezali H, Radzi Z, Yahya NA, Abu Kassim NH, Czernuszka J, et al.
    Skin Pharmacol Physiol, 2016;29(4):190-203.
    PMID: 27434176 DOI: 10.1159/000447017
    Collagen and elastin networks make up the majority of the extracellular matrix in many organs, such as the skin. The mechanisms which are involved in the maintenance of homeostatic equilibrium of these networks are numerous, involving the regulation of genetic expression, growth factor secretion, signalling pathways, secondary messaging systems, and ion channel activity. However, many factors are capable of disrupting these pathways, which leads to an imbalance of homeostatic equilibrium. Ultimately, this leads to changes in the physical nature of skin, both functionally and cosmetically. Although various factors have been identified, including carcinogenesis, ultraviolet exposure, and mechanical stretching of skin, it was discovered that many of them affect similar components of regulatory pathways, such as fibroblasts, lysyl oxidase, and fibronectin. Additionally, it was discovered that the various regulatory pathways intersect with each other at various stages instead of working independently of each other. This review paper proposes a model which elucidates how these molecular pathways intersect with one another, and how various internal and external factors can disrupt these pathways, ultimately leading to a disruption in collagen and elastin networks.
    Matched MeSH terms: Collagen/metabolism*; Collagen/radiation effects; Collagen/ultrastructure*
  12. Fulltext Identification polypeptide biomarkers of porcine skin gelatin by two-dimensional electrophoresis
    Aina, M.A., Amin, I., Raja Mohd Hafidz, R.N., Yaakob, C.M.
    International Food Research Journal, 2013;20(3):1395-1399.
    MyJurnal
    The peptide composition of gelatin is known to vary very common that the electrophoretic pattern of gelatin from one source differs from another source even for the same raw material. Therefore, the present study aimed to use proteomics field to identify gelatin polypeptides biomarker for depending on the condition under which collagen is hydrolyzed. Hence, it is porcine skins. The polypeptides obtained for porcine skin gelatins can be used as reference in future to detect the origins of gelatin added in the processed food. We compared porcine skin gelatin samples obtained from three producers. Total average numbers of polypeptides of porcine skin gelatins from company A, B and C were 303 ± 2.8, 285.5 ± 3.5 and 270.5 ± 4.9 spots respectively. 10 biomarkers were identified and presented in all different companies. We also did a mixture of porcine and bovine skin gelatin to detect the presence of these 10 biomarkers. The level of adulteration that could be detected was as low as 1.0% w/w
    Matched MeSH terms: Collagen
  13. Fulltext Isolation and characterization of acid soluble collagen (ASC) and pepsin soluble collagen (PSC) extracted from silver catfish (Pangasius sp.) skin
    Hukmi, N.M.M., Sarbon, N.M.
    International Food Research Journal, 2018;25(6):2601-2607.
    MyJurnal
    The aims of this study are to isolate and characterize acid soluble collagen (ASC) and pepsin soluble collagen (PSC) extracted from silver catfish (Pangasius sp.) skin. Isolated ASC and PSC collagen were characterized in terms of chemical composition (moisture, protein, fat and ash content), protein concentration, functional group, solubility, and morphological properties as compared to commercial collagen. Yields of ASC and PSC were 4.27% and 2.27%, respectively. The chemical compositions of raw skin were 34.64%, 2.81%, 3.68%, and 0.31%, while the chemical compositions of ASC and PSC were 94.21%, 3.48%, 0.81%, 59.15%, and 88.25%, 3.46%, 0.92%, and 29.24%, for moisture, protein, fat, and ash, respectively. ASC and PSC had protein concentrations of 2.27 mg/mL and 2.70 mg/mL, respectively. Functional group analysis revealed that both isolated collagens exhibited Amide A, II and III as a fingerprint for collagen structure. The highest solubility was found at pH 4 for ASC, pH 1 for PSC, and pH 5 for commercial collagen. The morphology of the isolated collagens was porous and they contained fibril. In conclusion, the characteristics of the isolated ASC and PSC from silver catfish (Pangasius sp.) skin indicate that value-added collagen can be produced from the alternative source of freshwater fish.
    Matched MeSH terms: Collagen
  14. pH as analytical indicator for managing pork meat quality
    Kim TW, Kim CW, Kwon SG, Hwang JH, Park DH, Kang DG, et al.
    Sains Malaysiana, 2016;45:1097-1103.
    In order to examine differences of meat quality traits depending on pH values post-mortem, the pH range was classified
    according to initial pH (pH45min) and ultimate pH (pH24hr) post-mortem. The differences of meat quality traits depending
    on sex were not changed by a number of amount, except for backfat thickness and fat content. The value of pH45min was
    positively correlated with pHdif, whereas pH24hr was negatively associated with lightness (CIE L*) and protein content. At
    pH45min post-slaughter, collagen content, fat content, shear force, water holding capacity and yellowness (CIE b*) showed
    lower values at the higher pH range of pH>6.7 than those of other ranges, but CIE L* and redness (CIE a*) presented
    the lowest value at the intermediate pH range of pH6.3~6.7. Conversely, at pH24hr post-slaughter, fat and moisture
    contents maintained the highest average values at the higher pH range of pH>6.1, but protein content showed higher
    value at the lower pH range of pH<5.7. Higher pH24hr appeared significantly lower shear force, but higher water holding
    capacity. CIE L*, a*, and b* values showed significantly higher values at the lowest region of pH24hr. Since meat quality
    characteristics seemed to be favored by consumers in rather than at the range of pH5.7~6.1, which showed significant
    differences of meat color, appearance, and meat juiciness, it is suggested that production of pork meat to appropriate
    pH value is performed by pig breeders and control measures taken during pre- and post-slaughters.
    Matched MeSH terms: Collagen
  15. Electrophoretic deposition of collagen/chitosan films with copper-doped phosphate glasses for orthopaedic implants
    Deen I, Selopal GS, Wang ZM, Rosei F
    J Colloid Interface Sci, 2022 Feb;607(Pt 1):869-880.
    PMID: 34536940 DOI: 10.1016/j.jcis.2021.08.199
    Coatings with bioactive properties play a key role in the success of orthopaedic implants. Recent studies focused on composite coatings incorporating biocompatible elements that can increase the nucleation of hydroxyapatite (HA), the mineral component of bone, and have promising bioactive and biodegradable properties. Here we report a method of fabricating composite collagen, chitosan and copper-doped phosphate glass (PG) coatings for biomedical applications using electrophoretic deposition (EPD). The use of collagen and chitosan (CTS) allows for the co-deposition of PG particles at standard ambient temperature and pressure (1 kPa, 25 °C), and the addition of collagen led to the steric stabilization of PG in solution. The coating composition was varied by altering the collagen/CTS concentrations in the solutions, as well as depositing PG with 0, 5 and 10 mol% CuO dopant. A monolayer of collagen/CTS containing PG was obtained on stainless steel cathodes, showing that deposition of PG in conjunction with a polymer is feasible. The mass of the monolayer varied depending on the polymer (collagen, CTS and collagen/CTS) and combination of polymer + PG (collagen-PG, CTS-PG and collagen/CTS-PG), while the presence of copper led to agglomerates during deposition at higher concentrations. The deposition yield was studied at different time points and showed a profile typical of constant voltage deposition. Increasing the concentration of collagen in the PG solution allows for a higher deposition yield, while pure collagen solutions resulted in hydrogen gas evolution at the cathode. The ability to deposit polymer-PG coatings that can mimic native bone tissue allows for the potential to fabricate orthopaedic implants with tailored biological properties with lower risk of rejection from the host and exhibit increased bioactivity.
    Matched MeSH terms: Collagen
  16. Collagens for surimi gel fortification: Type-dependent effects and the difference between type I and type II
    Zhao Y, Lu K, Piao X, Song Y, Wang L, Zhou R, et al.
    Food Chem, 2023 May 01;407:135157.
    PMID: 36529012 DOI: 10.1016/j.foodchem.2022.135157
    Surimi products have unsatisfactory gel properties. Hence, this study evaluates the effect of collagen-adding on surimi gel properties and provides the first observation results regarding collagen type influence. With higher water solubility and more charged amino acids than type II, collagen type I intertwines with surimi myofibrillar proteins better to induce higher exposure of protein functional domains, more sufficient conformational changes of myosin and greater formation of chemical forces among proteins. These enhancements accelerate the gelation rate, leading to a well-stabilized surimi gel. The collagen I-containing surimi gels show more compact structures with uniformly distributed smaller pores than those containing collagen II, thereby providing the final products with higher water holding capacity and better textural profiles. As such, the surimi gel fortification performance of collagen I and the well-elucidated collagen-myofibrillar protein interaction mechanism will guide the further exploitation of collagen as an effective additive in the food industry.
    Matched MeSH terms: Collagen
  17. Clinical and radiographic periodontal parameters and release of collagen degradation biomarkers in naswar dippers
    Daood U, Abduljabbar T, Al-Hamoudi N, Akram Z
    J Periodontal Res, 2018 Feb;53(1):123-130.
    PMID: 28940417 DOI: 10.1111/jre.12496
    BACKGROUND AND OBJECTIVE: The aim of the present study was to compare clinical periodontal parameters and to assess the release of C-telopeptides pyridinoline cross-links (ICTP) and C-terminal crosslinked telopeptide (CTX) from gingival collagen of naswar (NW) and non-naswar (control) dippers.

    MATERIAL AND METHODS: Eighty-seven individuals (42 individuals consuming NW and 45 controls) were included. Clinical (plaque index, bleeding on probing, probing depth and clinical attachment loss) and radiographic (marginal bone loss) periodontal parameters were compared among NW and control groups. Gingival specimens were taken from subjects in NW and control groups, assessed for ICTP and CTX levels (using ELISA) and analyzed using micro-Raman spectroscopy. The significance of differences in periodontal parameters between the groups was determined using Kruskal-Wallis and Mann-Whitney U tests. The percent loss of dry mass over exposure time and the rate of release of ICTP and CTX from all groups were compared using the paired t-test to examine the effects of exposure time.

    RESULTS: Clinical and radiographic periodontal parameters were significantly higher in the NW group than the control group (P collagen breakdown in the connective tissue of subjects in the NW group as a result of naswar usage.

    Matched MeSH terms: Collagen/metabolism*; Collagen Type I/metabolism*
  18. Characterization of the effect of chromium salts on tropocollagen molecules and molecular aggregates
    Sergeeva IA, Klinov DV, Schäffer TE, Dubrovin EV
    Int J Biol Macromol, 2023 Jul 01;242(Pt 2):124835.
    PMID: 37201883 DOI: 10.1016/j.ijbiomac.2023.124835
    Though the capability of chromium treatment to improve the stability and mechanical properties of collagen fibrils is well-known, the influence of different chromium salts on collagen molecules (tropocollagen) is not well characterized. In this study, the effect of Cr3+ treatment on the conformation and hydrodynamic properties of collagen was studied using atomic force microscopy (AFM) and dynamic light scattering (DLS). Statistical analysis of contours of adsorbed tropocollagen molecules using the two-dimensional worm-like chain model revealed a reduction of the persistence length (i.e., the increase of flexibility) from ≈72 nm in water to ≈56-57 nm in chromium (III) salt solutions. DLS studies demonstrated an increase of the hydrodynamic radius from ≈140 nm in water to ≈190 nm in chromium (III) salt solutions, which is associated with protein aggregation. The kinetics of collagen aggregation was shown to be ionic strength dependent. Collagen molecules treated with three different chromium (III) salts demonstrated similar properties such as flexibility, aggregation kinetics, and susceptibility to enzymatic cleavage. The observed effects are explained by a model that considers the formation of chromium-associated intra- and intermolecular crosslinks. The obtained results provide novel insights into the effect of chromium salts on the conformation and properties of tropocollagen molecules.
    Matched MeSH terms: Collagen; Tropocollagen*
  19. Characteristics and Young's Modulus of Collagen Fibrils from Expanded Skin Using Anisotropic Controlled Rate Self-Inflating Tissue Expander
    Manssor NA, Radzi Z, Yahya NA, Mohamad Yusof L, Hariri F, Khairuddin NH, et al.
    Skin Pharmacol Physiol, 2016;29(2):55-62.
    PMID: 26836267 DOI: 10.1159/000431328
    Mechanical properties of expanded skin tissue are different from normal skin, which is dependent mainly on the structural and functional integrity of dermal collagen fibrils. In the present study, mechanical properties and surface topography of both expanded and nonexpanded skin collagen fibrils were evaluated. Anisotropic controlled rate self-inflating tissue expanders were placed beneath the skin of sheep's forelimbs. The tissue expanders gradually increased in height and reached equilibrium in 2 weeks. They were left in situ for another 2 weeks before explantation. Expanded and normal skin samples were surgically harvested from the sheep (n = 5). Young's modulus and surface topography of collagen fibrils were measured using an atomic force microscope. A surface topographic scan showed organized hierarchical structural levels: collagen molecules, fibrils and fibers. No significant difference was detected for the D-banding pattern: 63.5 ± 2.6 nm (normal skin) and 63.7 ± 2.7 nm (expanded skin). Fibrils from expanded tissues consisted of loosely packed collagen fibrils and the width of the fibrils was significantly narrower compared to those from normal skin: 153.9 ± 25.3 and 106.7 ± 28.5 nm, respectively. Young's modulus of the collagen fibrils in the expanded and normal skin was not statistically significant: 46.5 ± 19.4 and 35.2 ± 27.0 MPa, respectively. In conclusion, the anisotropic controlled rate self-inflating tissue expander produced a loosely packed collagen network and the fibrils exhibited similar D-banding characteristics as the control group in a sheep model. However, the fibrils from the expanded skin were significantly narrower. The stiffness of the fibrils from the expanded skin was higher but it was not statistically different.
    Matched MeSH terms: Collagen/physiology*; Collagen/ultrastructure
  20. Fulltext Quantitative intrinsic auto-cathodoluminescence can resolve spectral signatures of tissue-isolated collagen extracellular matrix
    Zielinski MS, Vardar E, Vythilingam G, Engelhardt EM, Hubbell JA, Frey P, et al.
    Commun Biol, 2019;2:69.
    PMID: 30793047 DOI: 10.1038/s42003-019-0313-x
    By analyzing isolated collagen gel samples, we demonstrated in situ detection of spectrally deconvoluted auto-cathodoluminescence signatures of specific molecular content with precise spatial localization over a maximum field of view of 300 µm. Correlation of the secondary electron and the hyperspectral images proved ~40 nm resolution in the optical channel, obtained due to a short carrier diffusion length, suppressed by fibril dimensions and poor electrical conductivity specific to their organic composition. By correlating spectrally analyzed auto-cathodoluminescence with mass spectroscopy data, we differentiated spectral signatures of two extracellular matrices, namely human fibrin complex and rat tail collagen isolate, and uncovered differences in protein distributions of isolated extracellular matrix networks of heterogeneous populations. Furthermore, we demonstrated that cathodoluminescence can monitor the progress of a human cell-mediated remodeling process, where human collagenous matrix was deposited within a rat collagenous matrix. The revealed change of the heterogeneous biological composition was confirmed by mass spectroscopy.
    Matched MeSH terms: Collagen/metabolism*; Collagen/ultrastructure
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