scholarly journals The chemistry of the collagen cross-links. The absence of reduction of dehydrolysinonorleucine and dehydrohydroxylysinonorleucine in vivo

1971 ◽  
Vol 121 (2) ◽  
pp. 257-259 ◽  
Author(s):  
A. J. Bailey ◽  
Catherine M. Peach
Keyword(s):  
Soft Tissues ◽  
Cross Link ◽  
Collagen Fibres ◽  
Cross Links

Two aldimine bonds have been shown to be present as stabilizing cross-links in intact collagen fibres from soft tissues: dehydrohydroxylysinonorleucine as a major component and dehydrolysinonorleucine being present in trace quantities. In the highly insoluble collagens less dehydrohydroxylysinonorleucine is present but the proportion of dehydrolysinonorleucine increases. In elastin the latter aldimine is reduced in vivo to give a more stable cross-link but no comparable reduction could be detected with either of the aldimines present in collagen.

scholarly journals The chemistry of the collagen cross-links. The characterization of Fraction C, a possible artifact produced during the reduction of collagen fibres with borohydride

1973 ◽  
Vol 135 (4) ◽  
pp. 657-665 ◽  
Author(s):  
Simon P. Robins ◽  
Allen J. Bailey
Keyword(s):  
Aldol Condensation ◽  
Condensation Product ◽  
Reduced Form ◽  
Borohydride Reduction ◽  
Cross Link ◽  
Collagen Fibres ◽  
Isolation And Identification ◽  
Cross Links

The present paper describes the isolation and identification of a major radioactive component of borotritide-reduced collagen, previously designated Fraction C. The derived structure for the compound confirms that it is identical with the ‘post-histidine’ component described by Tanzer et al. (1973) and given the trivial name histidino-hydroxymerodesmosine. Detailed studies of the effects of acid pH on the formation of Fraction C after borohydride reduction demonstrated the apparent lability of the non-reduced form, thus confirming our previous findings (Bailey & Lister, 1968). Inhibition of the formation of this component by the acid treatment appears to be due to protonation of the histidine imidazole group. Since the only new component formed on reduction of the acid-treated fibres was the reduced aldol condensation product, these results indicate that neither the histidine nor the hydroxylysine residues can be involved in covalent linkage with the aldol condensation product in the native fibre. It is suggested therefore that the proposed non-reduced aldimine form of Fraction C does not exist as an intermolecular cross-link in vivo. Thus the presence of histidino-hydroxymerodesmosine as a tetrafunctional cross-link in reduced collagen fibres is a result of a base-catalysed reaction promoted by the borohydride-reduction procedure and this component must therefore be considered as an artifact.

scholarly journals A damage model for collagen fibres with an application to collagenous soft tissues

2020 ◽  
Vol 476 (2236) ◽  
pp. 20190821
Author(s):  
Gerhard A. Holzapfel ◽  
Ray W. Ogden
Keyword(s):  
Soft Tissues ◽  
Damage Model ◽  
Three Dimensional ◽  
Collagen Fibres ◽  
Physiological Loading ◽  
Cross Links ◽  
Complex Boundary ◽  
Tail Tendon ◽  
Similar Basis ◽  
Rat Tail

We propose a mechanical model to account for progressive damage in collagen fibres within fibrous soft tissues. The model has a similar basis to the pseudoelastic model that describes the Mullins effect in rubber but it also accounts for the effect of cross-links between collagen fibres. We show that the model is able to capture experimental data obtained from rat tail tendon fibres, and the combined effect of damage and collagen cross-links is illustrated for a simple shear test. The proposed three-dimensional framework allows a straightforward implementation in finite-element codes, which are needed to analyse more complex boundary-value problems for soft tissues under supra-physiological loading or tissues weakened by disease.

scholarly journals Cross-linking modifications of HDL apoproteins by oxidized phospholipids: structural characterization, in vivo detection, and functional implications

2020 ◽  
Vol 295 (7) ◽  
pp. 1973-1984
Author(s):  
Detao Gao ◽  
Mohammad Z. Ashraf ◽  
Lifang Zhang ◽  
Niladri Kar ◽  
Tatiana V. Byzova ◽  
...  
Keyword(s):  
Density Lipoprotein ◽  
Cross Linking ◽  
Oxidized Phospholipids ◽  
Cross Link ◽  
In Vivo Detection ◽  
Lysine Residues ◽  
Cross Links ◽  
Human Atheroma

Apolipoprotein A-I (apoA-I) is cross-linked and dysfunctional in human atheroma. Although multiple mechanisms of apoA-I cross-linking have been demonstrated in vitro, the in vivo mechanisms of cross-linking are not well-established. We have recently demonstrated the highly selective and efficient modification of high-density lipoprotein (HDL) apoproteins by endogenous oxidized phospholipids (oxPLs), including γ-ketoalkenal phospholipids. In the current study, we report that γ-ketoalkenal phospholipids effectively cross-link apoproteins in HDL. We further demonstrate that cross-linking impairs the cholesterol efflux mediated by apoA-I or HDL3 in vitro and in vivo. Using LC-MS/MS analysis, we analyzed the pattern of apoprotein cross-linking in isolated human HDL either by synthetic γ-ketoalkenal phospholipids or by oxPLs generated during HDL oxidation in plasma by the physiologically relevant MPO-H2O2-NO2− system. We found that five histidine residues in helices 5–8 of apoA-I are preferably cross-linked by oxPLs, forming stable pyrrole adducts with lysine residues in the helices 3–4 of another apoA-I or in the central domain of apoA-II. We also identified cross-links of apoA-I and apoA-II with two minor HDL apoproteins, apoA-IV and apoE. We detected a similar pattern of apoprotein cross-linking in oxidized murine HDL. We further detected oxPL cross-link adducts of HDL apoproteins in plasma and aorta of hyperlipidemic LDLR−/− mice, including cross-link adducts of apoA-I His-165–apoA-I Lys-93, apoA-I His-154–apoA-I Lys-105, apoA-I His-154–apoA-IV Lys-149, and apoA-II Lys-30–apoE His-227. These findings suggest an important mechanism that contributes to the loss of HDL's atheroprotective function in vivo.

scholarly journals The influence of 1-hydroxyethane-1,1-diphosphonate and dichloromethanediphosphonate on lysine hydroxylation and cross-link formation in rat bone, cartilage and skin collagen

1981 ◽  
Vol 196 (1) ◽  
pp. 303-310 ◽  
Author(s):  
H L Guenther ◽  
H E Guenther ◽  
H Fleisch
Keyword(s):  
Condensation Product ◽  
Bone Collagen ◽  
Cross Link ◽  
Skin Collagen ◽  
Cross Links ◽  
The Cross ◽  
Lysine Hydroxylation ◽  
And Cartilage ◽  
Rat Bone

The effects in vivo of dichloromethanediphosphonate and 1-hydroxyethane 1,1-diphosphonate on collagen solubility, hydroxylation of lysine and proline and on the formation of collagen intermolecular cross-links were studied by using rat bone, cartilage and skin tissues. Dichloromethanediphosphonate decreased bone collagen solubility both in acetic acid and after pepsin treatment. Although none of the diphosphonates had any effect on the hydroxylation of proline, dichloromethane-diphosphonate, but not 1-hydroxyethane-1,1-diphosphonate, increased the number of hydroxylysine residues in the alpha-chains of bone, skin and cartilage collagen. The stimulatory effect was dose-dependent. The dichloromethanediphosphonate-mediated increase in hydroxylysine residues in bone and cartilage was manifested in an increase of dihydroxylysinonorleucine, the cross-link that is formed by the condensation of two hydroxylysine residues. The cross-link hydroxylysinonorleucine, a condensation product of hydroxylysine and lysine, on the other hand, was decreased. The total number of intermolecular cross-links was not changed by the diphosphonate.

scholarly journals Instant tough bioadhesive with triggerable benign detachment

2020 ◽  
Vol 117 (27) ◽  
pp. 15497-15503 ◽  
Author(s):  
Xiaoyu Chen ◽  
Hyunwoo Yuk ◽  
Jingjing Wu ◽  
Christoph S. Nabzdyk ◽  
Xuanhe Zhao
Keyword(s):  
Wound Closure ◽  
Soft Tissues ◽  
Ex Vivo ◽  
Adhesion Formation ◽  
Interfacial Water ◽  
Mechanical Compliance ◽  
Tissue Surface ◽  
Potential Applications ◽  
Cross Links

Bioadhesives such as tissue adhesives, hemostatic agents, and tissue sealants have potential advantages over sutures and staples for wound closure, hemostasis, and integration of implantable devices onto wet tissues. However, existing bioadhesives display several limitations including slow adhesion formation, weak bonding, low biocompatibility, poor mechanical match with tissues, and/or lack of triggerable benign detachment. Here, we report a bioadhesive that can form instant tough adhesion on various wet dynamic tissues and can be benignly detached from the adhered tissues on demand with a biocompatible triggering solution. The adhesion of the bioadhesive relies on the removal of interfacial water from the tissue surface, followed by physical and covalent cross-linking with the tissue surface. The triggerable detachment of the bioadhesive results from the cleavage of bioadhesive’s cross-links with the tissue surface by the triggering solution. After it is adhered to wet tissues, the bioadhesive becomes a tough hydrogel with mechanical compliance and stretchability comparable with those of soft tissues. We validate in vivo biocompatibility of the bioadhesive and the triggering solution in a rat model and demonstrate potential applications of the bioadhesive with triggerable benign detachment in ex vivo porcine models.

Habitual side-specific loading leads to structural, mechanical and compositional changes in the patellar tendon of young and senior life-long male athletes

2021 ◽  
Author(s):  
Christian Couppé ◽  
Rene B. Svensson ◽  
Sebastian V. Skovlund ◽  
Jacob Kildevang Jensen ◽  
Christian Skou Eriksen ◽  
...  
Keyword(s):  
Patellar Tendon ◽  
Dna Content ◽  
Knee Extensor ◽  
Young Male ◽  
Cross Link ◽  
Cross Sectional ◽  
Specific Loading ◽  
3 Tesla Mri ◽  
Cross Links

Effects of life-long physical activity on tendon function have been investigated in cross-sectional studies, but these are at risk of "survivorship" bias. Here, we investigate if life-long side-specific loading is associated with greater cross-sectional area (CSA), mechanical properties, cell density (DNA content) and collagen cross-link composition of the male human patellar tendon (PT), in vivo. Nine seniors and six young male life-long elite badminton players and fencers were included. CSA of the PT obtained by 3-tesla MRI, and ultrasonography-based bilateral PT mechanics were assessed. Collagen fibril characteristics, enzymatic cross-links, non-enzymatic glycation (autofluorescence), collagen and DNA content were measured biochemically in PT biopsies. The elite athletes had a ≥15% side-to-side difference in maximal knee extensor strength, reflecting chronic unilateral sport-specific loading patterns. The PT CSA was greater on the lead extremity compared with the non-lead extremity (17 %, p=0.0001). Furthermore, greater tendon stiffness (18 %, p=0.0404) together with lower tendon stress (22 %, p=0.0005) and tendon strain (18 %, p=0.0433) were observed on the lead extremity. No effects were demonstrated from side-to-side for glycation, enzymatic cross-link, collagen, and DNA content (50%, p=0.1160). Moreover, tendon fibril density was 87±28 fibrils/μm2 on the lead extremity and 68±26 fibrils/μm2 on the non-lead extremity (28%, p=0.0544). Tendon fibril diameter was 86±14 nm on the lead extremity and 94±14 nm on the non-lead extremity (-9%, p=0.1076). These novel data suggest that life-long side-specific loading in males yields greater patellar tendon size and stiffness possibly with concomitant greater fibril density but without changes of collagen cross-link composition.

scholarly journals The chemistry of the collagen cross-links. Age-related changes in the reducible components of intact bovine collagen fibres

1973 ◽  
Vol 131 (4) ◽  
pp. 771-780 ◽  
Author(s):  
Simon P. Robins ◽  
Massami Shimokomaki ◽  
Allen J. Bailey
Keyword(s):  
Schiff Bases ◽  
Analytical Techniques ◽  
Growth Period ◽  
Postnatal Growth ◽  
Cross Link ◽  
Bovine Collagen ◽  
Age Related ◽  
Cross Links ◽  
The One

The change in the amounts of the three major reducible cross-links was followed throughout the bovine-life span. The major reducible cross-link in embryonic skin is 6,7-dehydro-Nε -(2-hydroxy-5-amino-5-carboxypentyl)hydroxylysine, but this is gradually replaced in the latter stages of gestation or early postnatal growth period by two other Schiff bases, 6,7-dehydro-Nε-(5-amino-5-carboxypentyl)hydroxylysine and a component not yet identified, designated Fraction C. These latter two Schiff bases increase in amount during the rapid growth period to a maximum, after which they then slowly decrease until at maturity they are virtually absent. The proportion of these Schiff bases closely reflects the rate of growth, i.e. the amount of newly synthesized collagen present at any one time. Similarly, the three Schiff bases present in tendon and the one in cartilage slowly decrease during maturation. No evidence for the possible stabilization of these aldimine bonds during maturation by reduction in vivo was found by three different analytical techniques. Concurrently with the decrease in the proportion of the Schiff bases some new reducible components increased during maturation, but their characterization as Nε-glycosylamines demonstrated that they were not related to the lysine-derived aldehyde components. The significance of these components in the aging process cannot at present be assessed. As no evidence was obtained for any new reducible cross-links replacing the Schiff bases, it is probable that the latter are intermediate cross-links and that during maturation they are stabilized to some as yet unknown non-reducible cross-link as previously proposed (Bailey, 1968).

Biological and biomedical applications of collagenous biomaterials

1990 ◽  
Vol 48 (3) ◽  
pp. 856-857
Author(s):  
Yasushi P. Kato ◽  
Michael G. Dunn ◽  
Frederick H. Silver ◽  
Arthur J. Wasserman
Keyword(s):  
Biomedical Applications ◽  
Soft Tissues ◽  
Collagen Fibers ◽  
Bone Collagen ◽  
Cover Slip ◽  
Fibroblast Migration ◽  
Cellular Expression ◽  
Defect Repair

Collagenous biomaterials have been used for growing cells in vitro as well as for augmentation and replacement of hard and soft tissues. The substratum used for culturing cells is implicated in the modulation of phenotypic cellular expression, cellular orientation and adhesion. Collagen may have a strong influence on these cellular parameters when used as a substrate in vitro. Clinically, collagen has many applications to wound healing including, skin and bone substitution, tendon, ligament, and nerve replacement. In this report we demonstrate two uses of collagen. First as a fiber to support fibroblast growth in vitro, and second as a demineralized bone/collagen sponge for radial bone defect repair in vivo.For the in vitro study, collagen fibers were prepared as described previously. Primary rat tendon fibroblasts (1° RTF) were isolated and cultured for 5 days on 1 X 15 mm sterile cover slips. Six to seven collagen fibers, were glued parallel to each other onto a circular cover slip (D=18mm) and the 1 X 15mm cover slip populated with 1° RTF was placed at the center perpendicular to the collagen fibers. Fibroblast migration from the 1 x 15mm cover slip onto and along the collagen fibers was measured daily using a phase contrast microscope (Olympus CK-2) with a calibrated eyepiece. Migratory rates for fibroblasts were determined from 36 fibers over 4 days.

A Comparative Study of the in vivo Distribution of 32P-Polyphosphates and 32P-Orthophosphate

1972 ◽  
Vol 11 (01) ◽  
pp. 70-78
Author(s):  
Esther Miller ◽  
Leopoldo Anghileri
Keyword(s):  
Radiation Dose ◽  
Comparative Study ◽  
Soft Tissues ◽  
Tumor Bearing ◽  
In Vivo Distribution ◽  
The Cross ◽  
Total Body

SummaryThe distribution of 32P-polyphosphates (lineal and cross-linked) and 32Porthophosphate in normal and tumor bearing animals has been studied. Differences between the cross-linked and the lineal form are related to a different degree of susceptibility to the hydrolysis by the phosphatases. In contrast to orthophosphate, the polyphosphates showed a lower accumulation in soft tissues which gives an advantageous reduction of the total body radiation dose.

scholarly journals Ultra-strong bio-glue from genetically engineered polypeptides

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Chao Ma ◽  
Jing Sun ◽  
Bo Li ◽  
Yang Feng ◽  
Yao Sun ◽  
...  
Keyword(s):  
Soft Tissues ◽  
Covalent Bond ◽  
Genetically Engineered ◽  
Supramolecular Interactions ◽  
Molar Ratio ◽  
High Adhesion ◽  
Strong Adhesion ◽  
Order Of Magnitude

AbstractThe development of biomedical glues is an important, yet challenging task as seemingly mutually exclusive properties need to be combined in one material, i.e. strong adhesion and adaption to remodeling processes in healing tissue. Here, we report a biocompatible and biodegradable protein-based adhesive with high adhesion strengths. The maximum strength reaches 16.5 ± 2.2 MPa on hard substrates, which is comparable to that of commercial cyanoacrylate superglue and higher than other protein-based adhesives by at least one order of magnitude. Moreover, the strong adhesion on soft tissues qualifies the adhesive as biomedical glue outperforming some commercial products. Robust mechanical properties are realized without covalent bond formation during the adhesion process. A complex consisting of cationic supercharged polypeptides and anionic aromatic surfactants with lysine to surfactant molar ratio of 1:0.9 is driven by multiple supramolecular interactions enabling such strong adhesion. We demonstrate the glue’s robust performance in vitro and in vivo for cosmetic and hemostasis applications and accelerated wound healing by comparison to surgical wound closures.

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