Micromechanical Modeling Study of Mechanical Inhibition of Enzymatic Degradation of Collagen Tissues

Abstract

This study investigates how the collagen fiber structure influences the enzymatic degradation of collagen tissues. We developed a micromechanical model of a fibrous collagen tissue undergoing enzymatic degradation based on two central hypotheses. The collagen fibers are crimped in the undeformed configuration. Enzymatic degradation is an energy activated process and the activation energy is increased by the axial strain energy density of the fiber. We determined the intrinsic degradation rate and characteristic energy for mechanical inhibition from fibril-level degradation experiments and applied the parameters to predict the effect of the crimped fiber structure and fiber properties on the degradation of bovine cornea and pericardium tissues under controlled tension. We then applied the model to examine the effect of the tissue stress state on the rate of tissue degradation and the anisotropic fiber structures that developed from enzymatic degradation.

Non‐enzymatic cross‐linking of collagen type II fibrils is tuned via osmolality switch

“…In contrast to hyper‐osmolality, hypo‐osmolality showed restrictive effects on the non‐enzymatic glycation cross‐linking, indicating that expanded collagen fibrils are less susceptible to react with l ‐threose. Our observations are in line with findings of previous research that underscored the importance of stretching the collagen molecules in various forms of molecular, fibrillary and tissue level, to protect them against enzymatic activity 7, 8, 9, 10. Sufficient compressive strain of the extracellular matrix, that is, 25% strain, has been shown to buckle the collagen fibrils23 and consequently affect the conformation of collagen building blocks, that is, amino acids, which is believed to affect the susceptibility to enzymatic degradation.…”

“…There is some evidence that stretching of collagen fibrils decelerates MMPs enzymatic activity 7, 9, 10, 11. This could be due to the 3D orientation of the amino acids that form the cleavage sites in the backbone of collagen fibrils, which might only interact with enzymes in a specific (low stretched) conformation.…”

“…[7][8][9] There is some evidence that stretching of collagen fibrils decelerates MMPs enzymatic activity. 7,[9][10][11] This could be due to the 3D orientation of the amino acids that form the cleavage sites in the backbone of collagen fibrils, which might only interact with enzymes in a specific (low stretched) conformation. Similarly, the essential amino acids involved in advanced glycation, namely arginine and lysin, 12 may need a specific 3D conformation to interact with sugars and create cross-links.…”

Manifestation of Pathological States of Numerous Diseases in the Largest Organ of the Human Body: (I) Basics and the Diseases of Tendon

“…To show the idea of their discoveries, in Figure 10 we show three lines of best fit (roughly) based on the data presented in Fig. 2 of [114]. International Journal of Clinical Medicine Such data suggest that tension may generally pull the collagen alpha chains into a tighter apposition, limiting enzyme access all along the molecule.…”

“…Therefore, there is evidence that the collagen monomer has an intrinsic protection against enzymatic digestion. Using the data of [111], incorporating mathematical model analysis (which is omitted here) the effective diameter (of the collagen monomer) versus time graphs for the zero load, a load of 46 nN, and a large load of 1054 nN was plotted with discrete points in [114]. To show the idea of their discoveries, in Figure 10 we show three lines of best fit (roughly) based on the data presented in Fig.…”