Cicatrice

Résumé

thumb|Cicatrice mineure au bras, environ un an après la blessure Une cicatrice est la partie visible d'une lésion du derme après la réparation du tissu, à la suite d'une blessure, ou une incision effectuée au cours d'une opération. La cicatrisation fait partie intégrante du processus de guérison. À part les lésions très mineures, chaque blessure (après un accident, une maladie, ou un acte chirurgical) engendre une cicatrice plus ou moins importante. Le tissu cicatriciel n'est pas identique au tissu qu'il remplace et est habituellement de qualité fonctionnelle inférieure. Par exemple, les cicatrices cutanées sont plus sensibles au rayonnement ultraviolet, les glandes sudoripares et les follicules pileux ne se développent pas sous la cicatrice ; la formation de cicatrices consécutives à un infarctus du myocarde provoque une perte de puissance du muscle cardiaque et augmente les risques d'arrêt cardiaque. Cependant, quelques tissus (par exemple l'os) peuvent guérir sans détérioration str

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Biologicals and fetal cell therapy for wound healing and scar management

Nathalie Hirt-Burri, Lee Ann Laurent-Applegate, Dominique Pioletti, Corinne Scaletta

Few biopharmaceutical preparations developed from biologicals are available for tissue regeneration and scar management. When developing biological treatments with cellular therapy, selection of cell types and establishment of consistent cell banks are crucial steps in whole-cell bioprocessing. Various cell types have been used in treatment of wounds to reduce scar to date including autolog and allogenic skin cells, platelets, placenta and amniotic extracts. Experience with fetal cells show that they may provide an interesting cell choice due to facility of out-scaling and known properties for wound healing without scar. Differential gene profiling has helped to point to potential indicators of repair which include cell adhesion, extracellular matrix, cytokines, growth factors and development. Safety has been evidenced in Phase I & II clinical fetal cell use for burn and wound treatments with different cell delivery systems. Overall fetal cells present technical and therapeutic advantages compared to other cell types for effective cell-based therapy for wound and scar management.

2011

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Objective: The MRL mouse strain shows extraordinary wound healing capacities. Some years ago, Leferovich et al. (Proc Natl Acad Sci U. S. A. 2001;98:9830-35) have reported the absence of scar formation after cryogenically-induced right ventricular myocardial infarcts in adult MRL mice. An independent group (Oh et al., Cardiovasc Pathol 2004; 13:203-6) found that MRL mice repair left ventricular ischemic infarcts after coronary artery ligation with regular scar formation. Given the divergent outcomes in infarct healing in MRL mice reported by those two studies, we have investigated whether MRL mice heal myocardial infarcts, without scar both in the cryoinjury and in the coronary ligation model. Methods and Results: Four different protocols of cryogenically induced right and left ventricular injury, as well as permanent ligation of the left anterior descending coronary artery, were tested in adult MRL and control C57Bl/6 mice. At 60 days after experimental infarction, MRL mice showed pronounced scarring of the affected right and left ventricular areas, with no significant differences in infarct size and thickness between MRL and C57Bl/6 mice using any of the five experimental protocols. Analysis of cell proliferation by 5-bromo-2' -deoxyuridine (BrdU) incorporation into the DNA did not show any difference between the two strains of mice after infarction. Histological analysis of infarct areas using picrosirius red staining did not show differences in extent of collagen and distribution between the two mouse strains. Conclusions: NIRL mice heal myocardial infarcts with scar formation in response to ischemic as well as to cryogenic injuries. (c) 2008 Elsevier Inc. All rights reserved.

Elsevier2008

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Photodynamic therapy (PDT) for cancer in the esophagus and bronchi with red (630 nm) light may occasionally lead to wall perforation and fistula. Therefore, the clin. use of a less penetrating wavelength (514 nm) was investigated for the curative treatment of nine superficial carcinomas in the esophagus and bronchi after photosensitization with Photofrin II. Tumors without infiltration beyond the submucosa in the esophagus and beyond the lamina propria in the bronchi were considered as superficial cancers. The outcome and complications were compared with those of 13 superficial cancers treated with PDT and 630 nm light. In addn., we evaluated histol. the extent of the long-term tissue damage and scarring following treatment of six esophageal cancers with either green or red light. At first endoscopic control, 7-10 days after PDT, tissue necrosis simply matched the illuminated area, without evidence of selective tumor damage. Six of nine tumors treated with 514 nm light had a complete response compared with nine of 13 after 630 nm irradn. No perforation or fistula occurred in either treatment group. However, severe chest pain and fever with or without pleural effusion, consistent with occult perforation, were obsd. in three patients after 630 nm illumination in the esophagus. Histol., fibrous scarring in the three distinct sites treated with green light was limited to the superficial layers of the esophagus. After red light treatment, transmural fibrosis with marked thinning of the esophageal wall was evident in two of the three specimens available for inspection. These results indicate that PDT with 514 nm light has the potential to cure superficial cancer in the esophagus and bronchi with essentially the same probability of success as red light. In the esophagus, green light prevents deep tissue damage, thus reducing the risk of perforation.

1998

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