Development of a Chitosan Nanofibrillar Scaffold for Skin Repair and Regeneration.
Tchemtchoua Tateu, Victor ; ; Aqil, Abdelhafid et al
in Biomacromolecules (2011), 12
The final goal of the present study was the development of a 3-D chitosan dressing that would shorten the healing time of skin wounds by stimulating migration, invasion, and proliferation of the relevant ... [more ▼]
The final goal of the present study was the development of a 3-D chitosan dressing that would shorten the healing time of skin wounds by stimulating migration, invasion, and proliferation of the relevant cutaneous resident cells. Three-dimensional chitosan nanofibrillar scaffolds produced by electrospinning were compared with evaporated films and freeze-dried sponges for their biological properties. The nanofibrillar structure strongly improved cell adhesion and proliferation in vitro. When implanted in mice, the nanofibrillar scaffold was colonized by mesenchymal cells and blood vessels. Accumulation of collagen fibrils was also observed. In contrast, sponges induced a foreign body granuloma. When used as a dressing covering full-thickness skin wounds in mice, chitosan nanofibrils induced a faster regeneration of both the epidermis and dermis compartments. Altogether our data illustrate the critical importance of the nanofibrillar structure of chitosan devices for their full biocompatibility and demonstrate the significant beneficial effect of chitosan as a wound-healing biomaterial. [less ▲]Detailed reference viewed: 39 (18 ULg)
Pathogenesis of abdominal aortic aneurysm (AAA) formation.
Limet, Raymond ; Richelle, Betty ; VERLOES, Alain et al
in Acta Chirurgica Belgica (1998), 98(5), 195-8Detailed reference viewed: 20 (5 ULg)
Activated forms of MMP2 and MMP9 in abdominal aortic aneurysms.
SAKALIHASAN, Natzi ; Delvenne, Philippe ; Richelle, Betty et al
in Journal of Vascular Surgery (1996), 24(1), 127-33
PURPOSE: This consistent observation of a reduction of the elastin concentration in abdominal aortic aneurysms (AAAs) has led us to investigate in AAA specimens two metalloproteinases that display ... [more ▼]
PURPOSE: This consistent observation of a reduction of the elastin concentration in abdominal aortic aneurysms (AAAs) has led us to investigate in AAA specimens two metalloproteinases that display elastase activity, MMP2 (gelatinase A/72kDa) and MMP9 (gelatinase B/92 kDa). METHODS: Samples of full-thickness aortic wall, adherent thrombus, and serum were collected in 10 patients with AAAs. Samples of normal aortic wall and serum were taken from 6 age-matched control patients. Quantitative gelatin-zymography and gelatinolytic soluble assays after acetyl-phenyl mercuric acid activation were performed on serum and tissue extracts, and the results were expressed in units on a comparative wet-weight basis. Histologic analysis was performed in parallel to score the inflammatory infiltrate. RESULTS: The luminal and parietal parts of the thrombus contained, respectively, 20- and 10-fold more gelantinolytic activity than the serum. The predominate form was MMP9. Although the total gelatinolytic activity was in the same range both in AAAs and in normal walls, a significantly higher proportion of MMP9 was found in the aneurysmal aortic walls. Furthermore, a significant proportion of MMP9 was under its processed active form, which was never observed in normal samples. A significantly higher proportion of MMP2 was also present as processed active form in AAA wall. This latter parameter positively correlated with the inflammatory score. CONCLUSIONS: The presence of activated MMP9 and MMP2 might contribute to the degradation of the extracellular matrix proteins that occurs during the development of aneurysms. [less ▲]Detailed reference viewed: 12 (6 ULg)
Modifications of the extracellular matrix of aneurysmal abdominal aortas as a function of their size.
SAKALIHASAN, Natzi ; HEYERES, Antoine ; Richelle, Betty et al
in European Journal of Vascular Surgery (1993), 7(6), 633-7
Collagen and elastin are the main extracellular matrix proteins providing the aortic wall with adequate mechanical properties and resistance for proper function. Our study aimed at investigating the ... [more ▼]
Collagen and elastin are the main extracellular matrix proteins providing the aortic wall with adequate mechanical properties and resistance for proper function. Our study aimed at investigating the relationship between the elastin concentration of the wall of normal and aneurysmal abdominal aortas (AAA), the collagen concentration, and its extractability, as a function of their size. Infrarenal aortas were collected from 30 patients undergoing operative repair of abdominal aortic aneurysm. Age-matched control samples were obtained from eight autopsies of individuals without vascular disease. Samples were divided into five groups according to the aortic diameter: control group (group N, n = 8); < 50 mm (group I, n = 6; between 50-75 mm (group II, n = 10); > 75 mm (group III, n = 7); and ruptured (group IV, n = 7). The collagen concentration in samples from group I was similar to the controls. An increased collagen concentration was observed in group II and remained at the same level in the largest and ruptured aneurysms. Extractability of collagen was found to be increased in group III and was even higher in group IV. A highly significant reduction in elastin concentration was observed in group I and there was progressive reduction with increasing diameter and rupture. A significant correlation could be established between aortic diameter, increased collagen extractability and decreased elastin content. [less ▲]Detailed reference viewed: 18 (3 ULg)
Experimental hypertension: early changes in collagen metabolism
Foidart, Jean-Michel ; Rorive, Georges ; et al
in Revue Médicale de Liège (1983), 38(12), 537-49Detailed reference viewed: 1 (0 ULg)