Pharmacology of fibrosis and tissue injury

Abstract

Methods controlling tissue fibrosis are classified into those specifically inhibiting various metabolic aspects of collagen selectively in the injured tissue (ascorbic acid deficiency, effect of agent chelating Fe 2+ , proline analogs, lathyrogens). The most promising method seems to be the blocking of crosslinks formation among collagen molecules by β-aminopropionitrile, a competitive inhibitor of a crosslinking enzyme, lysyl oxidase. The second group of methods is called nonspecific, as they affect any stage of inflammatory process preceding the activation of fibroblasts. The importance of activated macrophages in the stimulation of fibroblast is discussed. Finally, a new concept is proposed, indicating the function of zinc ions in the control of the integrity of biomembrances, tissue reactivity to noxious agents. It is suggested that zinc may control NADPH dependent lipid peroxidation at the membrane level by inhibiting NADPH oxidase activity. The implication of these ideas to lung fibrosis induced by silica or asbestos is discussed.

Monitoring of the repair process of surgically created lesions in equine superficial digital flexor tendons by use of computerized ultrasonography

“…Then, in the case of undisturbed repair, structural realignment of fibrils over larger distances should begin (reflected by an increase in the C ratio) through the restoration of incomplete endotendon septa (reflected by a decrease in the B ratio). In some cases, this development appears to be hampered, possibly by the precocious formation of mature cross-links, 43,44 which leads to the formation of an inferior quality of repair tissue that can be assumed to be functionally insufficient. This indicates that the period between 12 and 16 weeks after injury can be considered to be crucial in the process of tendon healing and that any attempts at influencing this process (eg, physical exercise, medication, or approaches such as focused shock wave treatments 45,46 ) should be undertaken before or during that period.…”

Structure-related echoes in ultrasonographic images of equine superficial digital flexor tendons

“…45 Second, because this routine resolves structure-related echoes from the original ultrasonographic image, the presence, amount and mutual arrangement of these echoes provide useful information about the degree of structural integrity and, thus, about the progress of tendon healing, which could be of great use for objective evaluation of treatments that claim to promote a better axial alignment of the structures in the tendon during the remodeling phase, as in the case of β-aminopropionitrile. 19,51 Third, as the correlation routine uses intact boundaries between tendon bundles and the surrounding endotendon septa, which act as continuous acoustic interfaces and result in steady echoes, a fading endotendon septation will be visualized as a reduction or, eventually, a disappearance of resolvable, structure-related echoes. For instance, this loss of intact septation can be seen in cases of localized histopathological changes such as necrosis or remodeling of tendon bundles.…”

Nondestructive Imaging of Live Human Keloid and Facial Tissue Using Multiphoton Microscopy

“…The occlusion produces a local state of hypoxia that could stimulate a fibroblastlike cell to produce an excess amount of collagen. 16 These oc- As a hypertrophic scar matures and flattens over time, these occluded microvessels degenerate. 13 The observation of the degeneration of these microvessels over time could provide a means to monitor therapy directed toward reducing microvessel growth and proliferation.…”