scholarly journals Model Systems for Evidencing the Mediator Role of Riboflavin in the UVA Cross-Linking Treatment of Keratoconus

Molecules ◽  
2021 ◽  
Vol 27 (1) ◽  
pp. 190
Author(s):  
Mihaela Monica Constantin ◽  
Cătălina Gabriela Corbu ◽  
Sorin Mocanu ◽  
Elena Irina Popescu ◽  
Marin Micutz ◽  
...  
Keyword(s):  
Hyaluronic Acid ◽  
Type I Collagen ◽  
Tear Film ◽  
Model Systems ◽  
Cross Linking ◽  
Type I ◽  
Paramagnetic Resonance ◽  
Uva Irradiation ◽  
Physico Chemical ◽  
Mediator Role

Riboflavin under UVA radiation generates reactive oxygen species (ROS) that can induce various changes in biological systems. Under controlled conditions, these processes can be used in some treatments for ocular or dermal diseases. For instance, corneal cross-linking (CXL) treatment of keratoconus involves UVA irradiation combined with riboflavin aiming to induce the formation of new collagen fibrils in cornea. To reduce the damaging effect of ROS formed in the presence of riboflavin and UVA, the CXL treatment is performed with the addition of polysaccharides (dextran). Hyaluronic acid is a polysaccharide that can be found in the aqueous layer of the tear film. In many cases, keratoconus patients also present dry eye syndrome that can be reduced by the application of topical solutions containing hyaluronic acid. This study presents physico-chemical evidence on the effect of riboflavin on collagen fibril formation revealed by the following methods: differential scanning microcalorimetry, rheology, and STEM images. The collagen used was extracted from calf skin that contains type I collagen similar to that found in the eye. Spin trapping experiments on collagen/hyaluronic acid/riboflavin solutions evidenced the formation of ROS species by electron paramagnetic resonance measurements.

Electroacupuncture Ameliorates Subchondral Bone Deterioration and Inhibits Cartilage Degeneration in Ovariectomised Rats

2018 ◽  
Vol 36 (1) ◽  
pp. 37-43 ◽  
Author(s):  
Jun Zhou ◽  
Peirui Zhong ◽  
Ying Liao ◽  
Jing Liu ◽  
Yuan Liao ◽  
...  
Keyword(s):  
Subchondral Bone ◽  
Type I Collagen ◽  
Cartilage Degeneration ◽  
Cross Linking ◽  
Control Group ◽  
Sham Operation ◽  
Type I ◽  
Trabecular Thickness ◽  
Ovx Rats ◽  
Time Point

Objectives To investigate the effects of electroacupuncture (EA) on subchondral bone mass and cartilage degeneration in an experimental animal model of osteoarthritis (OA) induced by ovariectomy (OVX). Methods Ninety 3-month-old female Sprague-Dawley rats were randomly divided into the following three groups (n = 30 each): sham operation without treatment (control group); OVX without treatment (OVX group);, and ovariectomy with EA treatment (EA group). Rats in the EA group received EA treatment from the day of OVX. Ten rats in each group were randomly killed at 4, 8 and 12 weeks after operation. Results EA reduced urine C-terminal cross-linking telopeptide of type I collagen from 4 weeks after OVX, reduced C-terminal cross-linking telopeptide of type II collagen and body weight from 8 weeks after OVX, and increased serum 17β-oestradiol from 4 weeks after OVX compared with the OVX group (all p<0.01). In the EA group, trabecular bone volume ratio, trabecular thickness and trabecular number increased, and trabecular separation were reduced at each time point compared with the OVX group (p<0.05, p<0.01, respectively). In the EA group, osteoprotegerin (OPG) expression was increased and receptor activator of nuclear factor kappa-B ligand (RANKL) expression was reduced at each time point compared with the OVX group (p<0.05, p<0.01, respectively). Mankin scores and mRNA expression of matrix metalloproteinase-13 (MMP-13) were lower in EA versus OVX groups at 12 weeks after OVX (both p<0.01). Conclusion The results suggest that EA inhibits subchondral bone loss by regulating RANK/RANKL/OPG signalling and protects articular cartilage by inhibiting MMP-13 in OVX rats.

Histologic Characterization of Rat Vocal Fold Scarring

2005 ◽  
Vol 114 (3) ◽  
pp. 183-191 ◽  
Author(s):  
Tomoko Tateya ◽  
Jin Ho Sohn ◽  
Ichiro Tateya ◽  
Diane M. Bless
Keyword(s):  
Hyaluronic Acid ◽  
Vocal Fold ◽  
Type I Collagen ◽  
Collagen Type ◽  
Control Level ◽  
Vocal Folds ◽  
Collagen Type I ◽  
Type I ◽  
Type Iii ◽  
Blue Stain

This study aimed to clarify the characteristics of rat vocal fold scarring by examining the alteration of key components in the extracellular matrix: hyaluronic acid, collagen, and fibronectin. Under monitoring with a 1.9-mm-diameter telescope, unilateral vocal fold stripping was performed, and larynges were harvested at 2, 4, 8, and 12 weeks after operation. The vocal folds were histologically analyzed with Alcian blue stain, trichrome stain, and immunofluorescence of collagen type I, collagen type III, and fibronectin. The scarred vocal folds showed less hyaluronic acid and more collagen types I and III than did the controls at all time points. Type III was stable for 12 weeks, while type I declined until 8 weeks and thereafter remained unchanged. Fibronectin increased for 4 weeks and then decreased; it was close to the control level at 8 and 12 weeks. These results suggest that the tissue remodeling process in scarred vocal folds slows down around 2 months after wounding.

scholarly journals Ιδιοπαθής υπερασβεστιουρία στην παιδική ηλικία

2017 ◽  
Author(s):  
Μαρία Παύλου
Keyword(s):  
Type I Collagen ◽  
Cross Linking ◽  
Type I ◽  
Nuclear Factor ◽  
Soluble Receptor ◽  
Calcium Sensing Receptor ◽  
Calcium Sensing ◽  
Receptor Activator ◽  
Carboxy Terminal ◽  
Nuclear Factor Kb

Η ιδιοπαθής υπερασβεστιουρία (ΙΥΑ) στα παιδιά έχει επιπολασμό 2,2-17,7%. Ποσοστό 2635% των ασθενών εμφανίζει μειωμένη οστική πυκνότητα, που αποδίδεται μάλλον σε αυξημένη οστική απορρόφηση και/ή οστικό ανασχηματισμό, καθώς καταγράφεται φυσιολογική κατά μήκος αύξηση των οστών στα περισσότερα παιδιά με ΙΥΑ. Περιορισμένες είναι οι μελέτες εκτίμησης βιοχημικών δεικτών οστικού μεταβολισμού, αλλά και γονιδιακού ελέγχου σε παιδιά με ΙΥΑ στην διεθνή βιβλιογραφία και καμία στην ελληνική. Επίσης, δεν πραγματοποιήθηκαν μελέτες εκτίμησης των κυτταροκινών οστεοκλαστογένεσης οστεοπροτεγερίνη (osteoprotegerin, OPG) και sRANKL (soluble receptor activator of nuclear factor kB ligand) σε ασθενείς με ΙΥΑ. Σκοπός της μελέτης ήταν η εκτίμηση των βιοχημικών δεικτών οστικής παραγωγής, αλκαλική φωσφατάση (alkaline phosphatase, ALP) και οστεοκαλσίνη (osteocalcin, OC) και οστικής απορρόφησης β-Crosslaps (serum Carboxy-terminal cross-linking telopeptide of type I collagen) και της OPG και sRANKL στον ορό σε παιδιά με ΙΥΑ. Επίσης έγινε γονιδιακή ανάλυση των πολυμορφισμών του γονιδίου του ασβεστιοευαίσθητου υποδοχέα (Calcium sensing Receptor, CaSR). Πενήντα παιδιά με ΙΥΑ αποτέλεσαν την ομάδα ασθενών και 60 υγιή παιδιά την ομάδα ελέγχου. Οι ασθενείς εκτιμήθηκαν κατά τον χρόνο της διάγνωσης και 3 μήνες μετά την εφαρμογή διαιτητικών οδηγιών αντιμετώπισης της ΙΥΑ. Οι ασθενείς της μελέτης μας είχαν σχετικά ήπια προς μέτρια υπερασβεστιουρία (6,49±2,03 mg/Kg/day) κατά την ένταξη στην μελέτη. Μετά την εφαρμογή των διατροφικών οδηγιών, μείωσαν σημαντικά τα επίπεδα του Ca στα ούρα 24ώρου και τον λόγο του Ca προς κρεατινίνη στα δείγματα ούρων, χωρίς όμως να φτάνουν τις φυσιολογικές τιμές. Τα επίπεδα της ALP και OC και το ύψος των ασθενών δεν διέφεραν από της ομάδας ελέγχου, που δείχνει ανεπηρέαστη οστική παραγωγή στους ασθενείς. Τα επίπεδα των β-Crosslaps των ασθενών, στους δύο χρόνους εκτίμησης, ήταν υψηλότερα από των μαρτύρων, ενώ καταγράφηκε τάση μείωσης της μέσης τιμής μετά την τρίμηνη παρέμβαση. Το εύρημα δείχνει αυξημένη οστική απορρόφηση στους ασθενείς με τάση βελτίωσης κατά τον επανέλεγχο. Ο λόγος β-Crosslaps/OC στους ασθενείς κατά την ένταξη στην μελέτη ήταν αυξημένος συγκριτικά με των μαρτύρων, καταγράφοντας υψηλότερο ρυθμό οστικής απορρόφησης συγκριτικά με οστικής παραγωγής. Τα επίπεδα των OPG και sRANKL των ασθενών, στους δύο χρόνους εκτίμησης δε διέφεραν από των μαρτύρων. Ωστόσο, ο λόγος sRANKL/OPG στους ασθενείς κατά την ένταξη στην μελέτη ήταν ελαφρά χαμηλότερος, πιθανά σαν απάντηση αντιρρόπησης του υψηλότερου ρυθμού οστεοκλαστογένεσης. Από την γονιδιακή ανάλυση των πολυμορφισμών A986S, R990G και Q1011E του CaSR, καταγράφηκε συσχέτιση μόνο του A986S με την ΙΥΑ στα παιδιά της μελέτης. Συμπερασματικά οι ασθενείς της μελέτης μας φαίνεται να έχουν φυσιολογική οστική παραγωγή, αλλά αυξημένη οστική απορρόφηση, που βελτιώθηκε μετά την παρέμβαση. Βρέθηκε συσχέτιση μόνο του πολυμορφισμού A986S του CaSR με την ΙΥΑ. Θεωρούμε χρήσιμη την εκτίμηση των βιοχημικών δεικτών οστικής παραγωγής ALP και OC και απορρόφησης β-Crosslaps στον ορό στα παιδιά με ΙΥΑ, ως μια μη επεμβατική μέθοδο ανίχνευσης διαταραχών οστικού μεταβολισμού και παρακολούθησης της αντιμετώπισης της.

Abstract 17388: Loss of Bone Morphogenetic Protein 9 (BMP9) Limits Survival and Paradoxically Increases Collagen Abundance, but Limits Collagen Cross-Linking in a Murine Model of Acute Myocardial Infarction

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Shreyas Bhave ◽  
Michele Esposito ◽  
Lija Swain ◽  
Xiaoying QIAO ◽  
Gregory Martin ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Bone Morphogenetic Protein ◽  
Murine Model ◽  
Cardiac Remodeling ◽  
Type I Collagen ◽  
Cross Linking ◽  
Type I ◽  
Morphogenetic Protein ◽  
Bone Morphogenetic Protein 9 ◽  
Collagen Cross Linking

Myocardial infarction (MI) is a major cause of heart failure (HF). HF is associated with adverse cardiac remodeling that is primarily driven by Transforming growth factor beta (TGFb1) mediated fibrosis and myocyte hypertrophy. We previously reported that loss of bone morphogenetic protein 9 (BMP9) promotes cardiac fibrosis in pressure-overload induced HF. No studies have explored a role for BMP9 in post MI cardiac remodeling. We hypothesize that loss of BMP9 may promote cardiac healing by stabilizing LV scar formation. To test this hypothesis, we subjected whole body BMP9 knockout (-/-) mice to left coronary artery ligation for two weeks followed by PV loop analysis and studied indices of cardiac remodeling. Compared to wild type (WT) controls BMP9-/- mice had significantly lower survival (83% vs 61%, p<0.001, respectively) with a higher rate of cardiac rupture(15% vs 90%). Compared to WT controls, surviving BMP9-/- mice had higher LVEDP, reduced LV dP/dt, and higher lung weight. Compared to WT mice, BMP9-/- mice had significantly higher levels of Type I collagen (2 fold p<0.05). Compared to WT mice, BMP9-/- mice had increased matrix metalloproteinases (MMP)-2 and MMP-9 (2.5 fold p<0.05) activity levels in the LV. Treatment of cultured primary human cardiac fibroblasts with recombinant BMP9 attenuated TGFb1-mediated Type I collagen and MMP-9 protein expression. To assess collagen content and cross-linking, two-photon excitation fluorescence imaging was performed and identified an increase in collagen abundance, but a trend towards lower collagen cross-linking in the LV of BMP9-/- mice compared to WT mice 2 weeks after MI. Our central finding is that loss of BMP9 is associated with reduced survival, increased propensity towards cardiac rupture, and increased LV collagen abundance, but reduced collagen integrity in a murine model of acute MI. These identify a potentially important functional role for BMP9 in post-infarct cardiac remodeling.

scholarly journals Hyaluronic acid, HAS1, and HAS2 are significantly upregulated during muscle hypertrophy

2012 ◽  
Vol 303 (5) ◽  
pp. C577-C588 ◽  
Author(s):  
Sarah Calve ◽  
Jahdonna Isaac ◽  
Jonathan P. Gumucio ◽  
Christopher L. Mendias
Keyword(s):  
Skeletal Muscle ◽  
Hyaluronic Acid ◽  
Type I Collagen ◽  
Muscle Growth ◽  
Type I ◽  
Muscle Adaptation ◽  
Cell Recruitment ◽  
Regeneration In Vitro ◽  
Muscle Progenitor Cell

Hyaluronic acid (HA) is a component of the extracellular matrix (ECM) in most vertebrate tissues and is thought to play a significant role during development, wound healing, and regeneration. In vitro studies have shown that HA enhances muscle progenitor cell recruitment and inhibits premature myotube fusion, implicating a role for this glycosaminoglycan in functional repair. However, the spatiotemporal distribution of HA during muscle growth and repair was unknown. We hypothesized that inducing hypertrophy via synergist ablation would increase the expression of HA and the HA synthases (HAS1–HAS3). We found that HA and HAS1–HAS3 were significantly upregulated within the plantaris muscle in response to Achilles tenectomy. HA concentration significantly increased 2.8-fold after 2 days but decreased towards levels comparable to age-matched controls by 14 days. Using immunohistochemistry, we found the colocalization of HAS1–HAS3 with macrophages, blood vessel epithelia, and fibroblasts varied in response to time and/or tenectomy. At the level of gene expression, only HAS1 and HAS2 significantly increased with respect to both time and tenectomy. The profiles of additional genes that influence ECM composition during muscle repair, tenascin-C, type I collagen, the HA-degrading hyaluronidases (Hyal) and matrix metalloproteinases (MMP) were also investigated. Hyal1 and Hyal2 were highly expressed in skeletal muscle but did not change after tenectomy; however, indicators of hypertrophy, MMP-2 and MMP-14, were significantly upregulated from 2 to 14 days. These results indicate that HA levels dynamically change in response to a hypertrophic stimulus and various cells may participate in this mechanism of skeletal muscle adaptation.

scholarly journals Dynamic Stretching of Fibrillar Collagen Enhances Cross-linking by Transglutaminas

2019 ◽  
Vol 4 (4) ◽  
pp. 2473011419S0038
Author(s):  
Nicolas Shealy ◽  
James Rex ◽  
Amy Bradshaw ◽  
Christopher Gross
Keyword(s):  
Molecular Weight ◽  
Type I Collagen ◽  
Cross Linking ◽  
Type I ◽  
Fibrillar Collagen ◽  
Collagen Gels ◽  
Cross Link ◽  
Dynamic Stretching ◽  
Insoluble Collagen ◽  
Static Conditions

Category: Basic Sciences/Biologics Introduction/Purpose: New approaches to improve tendon repair after injury are an active area of research. Critical properties of tendons are governed by the production and assembly of fibrillar collagens. Cross-linking of fibrillar collagen is a primary factor in determining the function and mechanical properties of the collagen fibers comprising Enzymatic cross-linking by lysyl oxidase in the telopeptide domain of collagen I and III is one determinant of collagen fibril assembly and is the best characterized biochemical cross-link. Transglutaminase catalyzes the modification of lysine residues that in turn form an n-e-glutamyl lysine bond between proteins in the extracellular space. We hypothesize that transglutaminase-dependent modification of collagen in tendons is also a principal determinant of tendon strength and function and is dependent upon tension. Methods: 3-D collagen gels were generated from acid solubilized type I collagen with telopeptides (Advanced BioMatrix). Collagen gels were plated and loaded into a MechanoCulture FX apparatus (CellScale). Gels were subjected to a 10% stretch for 24 hrs at 37°C at 2hz (dynamic) or no stretch, static controls. Gels exposed to enzymatic cross-linking were incubated with either 2.4 ng of recombinant Transglutaminase 2 (Axxora) in a 10 mM Ca2+ solution. Inhibition and labeling of transglutaminase substrates was performed by incubation of collagen gels with 0.2 mM aminopentyl biotinamide in DMSO. Soluble collagen was separated from insoluble collagen by centrifugation at 10,000G. Insoluble fractions were boiled in SDS-Laemmli buffer prior to separation by SDS-PAGE. Collagen in soluble and insoluble fractions was evaluated by Coomassie stain whereas transglutaminase modification was detected via western blot using streptavidin conjugated horse radish peroxidase to detect biotinylated proteins. Results: Evaluation of collagen gels subjected to dynamic versus static stretch revealed minor differences in insoluble collagen incorporation in the two conditions. Notably, higher molecular weight cross-linked forms of collagen appeared to be higher in dynamic versus static gels. In the presence of transglutaminase, differences in higher molecular weight cross-linked forms of collagen, beta-bands, were also detected. Finally, incorporation of biotinylated transglutaminase substrate into collagen alpha bands was enriched in dynamic versus static cultures. Hence, preliminary results support a differential role for transglutaminase modification in collagen under cyclic tension versus static conditions. Conclusion: A better understanding of the role of dynamic stretching and differential tension in the regulation of collagen cross- link formation is predicted to contribute to improved strategies to treat injured tendons.

Evaluation of plasma carboxy-terminal cross-linking telopeptide of type I collagen concentration in horses

2004 ◽  
Vol 65 (1) ◽  
pp. 104-109 ◽  
Author(s):  
Bianca Carstanjen ◽  
Nicholas R. Hoyle ◽  
Annick Gabriel ◽  
Olaf Hars ◽  
Charlotte Sandersen ◽  
...  
Keyword(s):  
Type I Collagen ◽  
Cross Linking ◽  
Type I ◽  
Collagen Concentration ◽  
Carboxy Terminal
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