In VitroandIn VivoAssessment of Oral Autologous Artificial Connective Tissue Characteristics That Influence Its Performance as a Graft

Treatment with type-I collagen scaffolds in patients with venous ulcers. Case report

Introduction: Chronic venous insufficiency affects about 5% of the global adult population. Venous leg ulcers are one of the most frequent complications of this pathology, with a global prevalence of 2%. This disease affects both the quality of life of patients and, due to the high cost of the treatment, the health system. Compressive therapy and moist wound healing have been the gold standard treatment. However, when complications occur, they may not be effective.Case report: This is the case of a 66-year-old female patient with venous ulcers on her lower limbs and symptoms of fever and local pain that did not respond to conventional therapies. The patient was treated with a new dermal substitute made of an acellular type-I collagen membrane, which promotes the closure of the ulcer by stimulating the replacement of injured tissue with tissue similar to the healthy one. The condition of the patient improved at 16 weeks, and after 8 months of treatment there was no recurrence of the lesions.Conclusions: Acellular type-I collagen membrane developed by the Tissue Engineering Working Group of the Department of Pharmacy of the Universidad Nacional de Colombia is effective in treating venous ulcers of the lower limbs. Its low cost facilitates the access of the whole population to therapies based on its application.

Preclinical evaluation of collagen type I scaffolds, including gelatin-collagen microparticles and loaded with a hydroglycolic Calendula officinalis extract in a lagomorph model of full-thickness skin wound

Previously, we have developed collagen type I scaffolds including microparticles of gelatin-collagen type I (SGC) that are able to control the release of a hydroglycolic extract of the Calendula officinalis flower. The main goal of the present work was to carry out the preclinical evaluation of SGC alone or loaded with the C. officinalis extract (SGC-E) in a lagomorph model of full-thickness skin wound. A total of 39 rabbits were distributed in three groups, of 13 animals each. The first group was used to compare wound healing by secondary intention (control) with wound healing observed when wounds were grafted with SGC alone. Comparison of control wounds with wounds grafted with SGC-E was performed in the second group, and comparison of wounds grafted with SGC with wounds grafted with SGC-E was performed in the third group. Clinical follow-ups were carried in all animals after surgery, and histological and histomorphometric analyses were performed on tissues taken from the healed area and healthy surrounding tissue. Histological and histomorphometric results indicate that grafting of SGC alone favors wound healing and brings a better clinical outcome than grafting SGC-E. In vitro collagenase digestion data suggested that the association of the C. officinalis extract to SGC increased the SGC-E cross-linking, making it difficult to degrade and affecting its biocompatibility.

Real-time quantification of proteins secreted by artificial connective tissue made from uni- or multidirectional collagen I scaffolds and oral mucosa fibroblasts

Previously, we found that oral autologous artificial connective tissue (AACT) had a different protein secretion profile to that of clot-embedded AACT. Other oral mucosa substitutes, having different cell types and scaffolds, had dissimilar secretion profiles of proteins (including that for AACT) that influence healing outcome; thus, to ascertain the profiles of factors secreted by artificial tissue and whether they are influenced by their microstructure might help in understanding their bioactivity. An important component of tissue microstructure is the fiber orientation of the scaffold used for manufacturing it. This work developed a surface plasmon resonance (SPR) methodology to quantify factors secreted by oral artificial connective tissue (ACT) in culture medium, and a method to manufacture unidirectional laminar collagen I scaffolds. The SPR methodology was used for assessing differences in the protein secretion profile of ACT made with collagen scaffolds having different fiber orientation (unidirectional vs multidirectional). Oral fibroblasts seeded onto unidirectional scaffolds increased the secretion of six factors involved in modulating healing compared to those seeded onto multidirectional scaffolds. Histological analysis of uni- and multidirectional ACT showed that cells differ in their alignment and morphology. This SPR-methodology led to nanoscale detection of paracrine factors and might be useful to study biomarkers of three-dimensional cell growth, cell differentiation, and wound-healing progression.