Collagen Cross-linking and Ultimate Tensile Strength in Dentin

2004 ◽  
Vol 83 (10) ◽  
pp. 807-810 ◽  
Author(s):  
P.A. Miguez ◽  
P.N.R. Pereira ◽  
P. Atsawasuwan ◽  
M. Yamauchi
Keyword(s):  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Dental Materials ◽  
Cross Linking ◽  
Anatomical Location ◽  
Dentinal Tubules ◽  
Root Dentin ◽  
Cross Links ◽  
The Difference ◽  
Collagen Cross Linking

Several studies have indicated differences in bond strength of dental materials to crown and root dentin. To investigate the potential differences in matrix properties between these locations, we analyzed upper root and crown dentin in human third molars for ultimate tensile strength and collagen biochemistry. In both locations, tensile strength tested perpendicular to the direction of dentinal tubules (undemineralized crown = 140.4 ± 48.6/root = 95.9 ± 26.1; demineralized crown = 16.6 ± 6.3/root = 29.0 ± 12.4) was greater than that tested parallel to the tubular direction (undemineralized crown = 73.1 ± 21.2/root = 63.2 ± 22.6; demineralized crown = 9.0 ± 3.9/root = 16.2 ± 8.0). The demineralized specimens showed significantly greater tensile strength in root than in crown. Although the collagen content was comparable in both locations, two major collagen cross-links, dehydrodihydroxylysinonorleucine/its ketoamine and pyridinoline, were significantly higher in the root (by ~ 30 and ~ 55%, respectively) when compared with those in the crown. These results indicate that the profile of collagen cross-linking varies as a function of anatomical location in dentin and that the difference may partly explain the site-specific tensile strength.

Biomechanical comparison of the Lim/Tsai tendon repair with a modified method using a single looped suture

2017 ◽  
Vol 42 (9) ◽  
pp. 915-919 ◽  
Author(s):  
Min Kai Chang ◽  
Yoke Rung Wong ◽  
Shian Chao Tay
Keyword(s):  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Mechanical Performance ◽  
Tendon Repair ◽  
Original Method ◽  
Flexor Digitorum Profundus ◽  
Loading Test ◽  
Modified Method ◽  
Cycle Loading ◽  
The Difference

The Lim/Tsai tendon repair technique has been modified clinically to achieve a 6-strand repair using a single looped suture with one extratendinous knot. We compared biomechanical performance of the original and modified methods using 20 porcine flexor digitorum profundus tendons. The ultimate tensile strength, load to 2 mm gap force, mode of failure, and time taken to repair each tendon were recorded during a single cycle loading test in 10 tendons with each repair method. We found that despite having the same number of core strands, the single looped suture modified Lim/Tsai technique possessed significantly greater ultimate tensile strength and load to 2 mm gap force. Also, less repair time was required. We conclude that the modified 6-strand repair using a single looped suture has better mechanical performance than the original method. The difference likely was due to the changes in locations of the knots and subsequent load distribution during tendon loading.

scholarly journals Overhydroxylation of Lysine of Collagen Increases Uterine Fibroids Proliferation: Roles of Lysyl Hydroxylases, Lysyl Oxidases, and Matrix Metalloproteinases

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Marwa Kamel ◽  
Mohamed Wagih ◽  
Gokhan S. Kilic ◽  
Concepcion R. Diaz-Arrastia ◽  
Mohamed A. Baraka ◽  
...  
Keyword(s):  
Matrix Metalloproteinases ◽  
Treatment Options ◽  
Uterine Fibroids ◽  
Cross Linking ◽  
Ki 67 ◽  
Subsequent Formation ◽  
Lysyl Oxidases ◽  
Cross Links ◽  
Collagen Cross Linking

The role of the extracellular matrix (ECM) in uterine fibroids (UF) has recently been appreciated. Overhydroxylation of lysine residues and the subsequent formation of hydroxylysylpyridinoline (HP) and lysylpyridinoline (LP) cross-links underlie the ECM stiffness and profoundly affect tumor progression. The aim of the current study was to investigate the relationship between ECM of UF, collagen and collagen cross-linking enzymes [lysyl hydroxylases (LH) and lysyl oxidases (LOX)], and the development and progression of UF. Our results indicated that hydroxyl lysine (Hyl) and HP cross-links are significantly higher in UF compared to the normal myometrial tissues accompanied by increased expression of LH (LH2b) and LOX. Also, increased resistance to matrix metalloproteinases (MMP) proteolytic degradation activity was observed. Furthermore, the extent of collagen cross-links was positively correlated with the expression of myofibroblast marker (α-SMA), growth-promoting markers (PCNA; pERK1/2;FAKpY397; Ki-67; and Cyclin D1), and the size of UF. In conclusion, our study defines the role of overhydroxylation of collagen and collagen cross-linking enzymes in modulating UF cell proliferation, differentiation, and resistance to MMP. These effects can establish microenvironment conducive for UF progression and thus represent potential target treatment options of UF.

scholarly journals Chemistry of collagen cross-linking: biochemical changes in collagen during the partial mineralization of turkey leg tendon

1997 ◽  
Vol 322 (2) ◽  
pp. 535-542 ◽  
Author(s):  
Lynda KNOTT ◽  
John F. TARLTON ◽  
Allen J. BAILEY
Keyword(s):  
Collagen Matrix ◽  
Cross Linking ◽  
Cross Link ◽  
Lysine Residues ◽  
Collagen Mineralization ◽  
Cross Links ◽  
The Cross ◽  
Calcified Tissues ◽  
Turkey Leg Tendon ◽  
Collagen Cross Linking

With age, the proximal sections of turkey leg tendons become calcified, and this phenomenon has led to their use as a model for collagen mineralization. Mineralizing turkey leg tendon was used in this study to characterize further the composition and cross-linking of collagen in calcified tissues. The cross-link profiles of mineralizing collagen are significantly different from those of other collagenous matrices with characteristically low amounts of hydroxylysyl-pyridinoline and the presence of lysyl-pyridinoline and pyrrolic cross-links. However, the presence of the immature cross-link precursors previously reported in calcifying tissues was not supported in the present study, and was found to be due to the decalcification procedure using EDTA. Analysis of tendons from young birds demonstrated differences in the cross-link profile which indicated a higher level of hydroxylation of specific triple-helical lysines involved in cross-linking of the proximal tendon. This may be related to later calcification, suggesting that this part of the tendon is predestined to be calcified. The minimal changes in lysyl hydroxylation in both regions of the tendon with age were in contrast with the large changes in the cross-link profile, indicating differential hydroxylation of the helical and telopeptide lysine residues. Changes with age in the collagen matrix, its turnover and thermal properties in both the proximal and distal sections of the tendon clearly demonstrate that a new and modified matrix is formed throughout the tendon, and that a different type of matrix is formed at each site.

Collagen cross-linking mediated by lysyl hydroxylase 2: an enzymatic battlefield to combat fibrosis

2019 ◽  
Vol 63 (3) ◽  
pp. 377-387 ◽  
Author(s):  
Bram Piersma ◽  
Ruud A. Bank
Keyword(s):  
Organ Failure ◽  
Molecular Basis ◽  
Repair Process ◽  
Cross Linking ◽  
Collagen Network ◽  
Lysyl Hydroxylase ◽  
Cross Links ◽  
Collagen Cross Linking ◽  
Excessive Accumulation

Abstract The hallmark of fibrosis is an excessive accumulation of collagen, ultimately leading to organ failure. It has become evident that the deposited collagen also exhibits qualitative modifications. A marked modification is the increased cross-linking, leading to a stabilization of the collagen network and limiting fibrosis reversibility. Not only the level of cross-linking is increased, but also the composition of cross-linking is altered: an increase is seen in hydroxyallysine-derived cross-links at the expense of allysine cross-links. This results in irreversible fibrosis, as collagen cross-linked by hydroxyallysine is more difficult to degrade. Hydroxyallysine is derived from a hydroxylysine in the telopeptides of collagen. The expression of lysyl hydroxylase (LH) 2 (LH2), the enzyme responsible for the formation of telopeptidyl hydroxylysine, is universally up-regulated in fibrosis. It is expected that inhibition of this enzyme will lead to reversible fibrosis without interfering with the normal repair process. In this review, we discuss the molecular basis of collagen modifications and cross-linking, with an emphasis on LH2-mediated hydroxyallysine cross-links, and their implications for the pathogenesis and treatment of fibrosis.

scholarly journals Age-related changes in the physical properties, cross-linking, and glycation of collagen from mouse tail tendon

2020 ◽  
Vol 295 (31) ◽  
pp. 10562-10571 ◽  
Author(s):  
Melanie Stammers ◽  
Irina M. Ivanova ◽  
Izabella S. Niewczas ◽  
Anne Segonds-Pichon ◽  
Matthew Streeter ◽  
...  
Keyword(s):  
The Other ◽  
Cross Linking ◽  
Structural Protein ◽  
Cross Link ◽  
Age Related ◽  
Cross Links ◽  
Tail Tendon ◽  
Collagen Cross Linking ◽  
Age Related Changes ◽  
Tendon Collagen

Collagen is a structural protein whose internal cross-linking critically determines the properties and functions of connective tissue. Knowing how the cross-linking of collagen changes with age is key to understanding why the mechanical properties of tissues change over a lifetime. The current scientific consensus is that collagen cross-linking increases with age and that this increase leads to tendon stiffening. Here, we show that this view should be reconsidered. Using MS-based analyses, we demonstrated that during aging of healthy C57BL/6 mice, the overall levels of collagen cross-linking in tail tendon decreased with age. However, the levels of lysine glycation in collagen, which is not considered a cross-link, increased dramatically with age. We found that in 16-week-old diabetic db/db mice, glycation reaches levels similar to those observed in 98-week-old C57BL/6 mice, while the other cross-links typical of tendon collagen either decreased or remained the same as those observed in 20-week-old WT mice. These results, combined with findings from mechanical testing of tendons from these mice, indicate that overall collagen cross-linking in mouse tendon decreases with age. Our findings also reveal that lysine glycation appears to be an important factor that contributes to tendon stiffening with age and in diabetes.

Thermoreversible cross-linking of maleated natural rubber with glycerol

2018 ◽  
Vol 51 (5) ◽  
pp. 406-420 ◽  
Author(s):  
Nuttida Srirachya ◽  
Takaomi Kobayashi ◽  
Kumarjyoti Roy ◽  
Kanoktip Boonkerd
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Natural Rubber ◽  
Succinic Anhydride ◽  
Processing Method ◽  
Cross Linking ◽  
Hydroxyl Groups ◽  
Reactive Processing ◽  
Cross Links ◽  
Maleated Natural Rubber

In this article, thermoreversible covalent cross-linking of maleated natural rubber (MNR) with glycerol was studied. Firstly, NR was grafted with maleic anhydride using a reactive processing method. The result showed that MNR was successfully obtained without the addition of initiator. The highest grafting was 1.76%. Secondly, the obtained MNR was dissolved in toluene and then mixed with glycerol, which is used in this study as the thermoreversible cross-linking agent. Fourier transform infrared spectra of the casted MNR film mixed with glycerol showed that upon heating, covalent ester cross-links were formed via the reaction of succinic anhydride ring with hydroxyl groups of glycerol. The swelling test indicated that the swelling index (%) decreased with increasing glycerol loading. This indicated that the degree of cross-linking directly depended on the amount of glycerol. The tensile strength and modulus were significantly improved upon increasing the level of cross-linking. The MNR cross-linked with glycerol can be remolded at 150°C more than three times. After remolding, the mechanical properties decreased with increasing recycling round.

scholarly journals Non-enzymic glycation of collagen inhibits binding of oxidized low-density lipoprotein

1993 ◽  
Vol 293 (3) ◽  
pp. 661-666 ◽  
Author(s):  
N Kalant ◽  
S McCormick ◽  
M A Parniak
Keyword(s):  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Cross Linking ◽  
Low Density ◽  
Collagen Gels ◽  
Oxidized Low Density Lipoprotein ◽  
Agarose Beads ◽  
Cross Links ◽  
The Difference ◽  
Intermolecular Distances

We have examined the effect of non-enzymic glycation of native soluble collagen, in solution or in gels, on binding of oxidized low-density lipoprotein (LDL). We found the following. (1) Glycation markedly inhibited binding of LDL. This is contrary to results previously reported; the difference may be attributable to the use of detergent- and heat-denatured collagen, covalently bound to agarose beads, in the earlier study. (2) With increased duration of glycation, collagen solution would not gel, and preformed gels dissolved. (3) [14C]Glucose bound to collagen gels dissociated slowly, even at pH 5, suggesting that it was not present as a Schiff's base; in addition, ketoamines, pentosidine and fluorescent advanced glycation products were not detectable in glycated collagen gels, although they accumulated in tendon collagen glycated under the same conditions. It is hypothesized that the difference in glycation effects between gel and tendon may be due to the strength of cross-linking before glycation: the increase in intermolecular distance in collagen fibrils which results from glycation disrupts the fibrils in gels, preventing binding of LDL and formation of glycation-dependent cross-links, whereas the extensive cross-linking in tendon maintains the intermolecular distances within a range which permits formation of glycation cross-links.

scholarly journals Molecular processes of corneal collagen cross-linking in keratoconus therapy

2018 ◽  
Vol 4 (1) ◽  
pp. 489-492
Author(s):  
Steven Melcher ◽  
Eberhard Spörl ◽  
Edmund Koch ◽  
Gerald Steiner
Keyword(s):  
Mechanical Stability ◽  
Attenuated Total Reflection ◽  
Secondary Amines ◽  
Cross Linking ◽  
Therapeutic Effects ◽  
Corneal Tissue ◽  
In Situ Experiments ◽  
Cross Links ◽  
Collagen Cross Linking ◽  
Corneal Collagen

AbstractCorneal collagen cross-linking (CXL) with riboflavin and UVA light is a therapeutic procedure to restore the mechanical stability of corneal tissue. The treatment method applies to pathological tissue changes, such as keratoconus. It induces the photochemical formation of new collagen cross-links. Although therapeutic effects are indisputable, the exact molecular process of CXL and how cross-links are formed is still unclear. In this work, Fouriertransform infrared (FT-IR) spectroscopy is used to investigate the cross-linking process. For that purpose, in-situ experiments with porcine corneas are carried out using attenuated total reflection (ATR) spectroscopy. Furthermore, IR micro-spectroscopic imaging in transmission mode is used to investigate thin tissue sections of the cornea and initial approaches for the distinction of cross-linked and untreated tissue by IR microspectroscopic imaging were performed. Multivariate methods are applied to access changes that occur as a result of CXL. It is shown that spectral changes after cross-linking are caused predominantly by an increase of methyl- and methylene groups as well as primary and secondary amines. In addition, a decrease of carbonyl groups could be observed.

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