Human Amniotic Membrane as a Delivery Matrix for Articular Cartilage Repair

Abstract

The purpose of this study is to evaluate the feasibility of human amniotic membrane (HAM) as a chondrocyte carrier by assessing cell proliferation and maintenance of phenotype in vitro and cartilage regeneration in vivo. Intact HAM was treated with 0.1% trypsin-ethylenediaminetetraacetic acid (EDTA) for 15 min and the epithelial cells removed to make a denuded HAM. Rabbit articular chondrocytes were then seeded on three different HAM substrates: the epithelial side of intact HAM (IHE), basement side of denuded HAM (DHB), and stromal side of denuded HAM (DHS). These cell-substrate specimens were cultured for up to 4 weeks, and cell proliferation rate and phenotypic stability were examined at weeks 1 and 4. While chondrocytes grew in monolayer fashion on the surface of IHE and DHB substrates, the cells seeded in DHS penetrated and spread into the whole thickness of the stromal layer. The proliferating activity of chondrocytes in DHB was continuously up-regulated. A similar proliferating activity was observed in DHS in the first week, which remained stable for up to 4 weeks. The expression of type II collagen gradually increased with time in the DHS group, while it gradually decreased in the DHB group or was not detected at all in the IHE group. These results suggested that denuded HAM was able to support chondrocyte proliferation and maintenance of phenotype in vitro, seemingly more favorable when DHS was used. Based on this data, the DHS with chondrocytes was used to cover rabbit osteochondral defect with the stromal side facing in. The defect area was successfully regenerated with hyaline cartilage in the Safranin-O stain and International Cartilage Repair Society (ICRS) scoring after 8 weeks of implantation. In conclusion, our findings suggest that denuded HAM could be one of the ideal cell carrier matrices for cartilage regeneration.

Rolling the Human Amnion to Engineer Laminated Vascular Tissues

“…A wide range of methods specific for hAM decellularization have been described, including treatment with the ionic surfactant SDS as used in these investigations. 14,20,21,[34][35][36] SEM and histology data confirm previous findings, 20,21 that SDS decellularization was efficient at removing whole cells, with images showing the ECM to be largely free of cellular remnants.…”

“…The hAM is an abundant birthing tissue that, due to its unique structure, composition, and neonatal derivation, has had promising results when used in a number of tissue repair applications. [11][12][13][14][15][16][17]33 Based on these clinical successes and a novel approach that takes advantage of the hAM's unique properties, we have developed a concentric rolling approach that aims at rapidly forming cell-dense and mechanically stable tissue-engineered blood vessels.…”

“…[11][12][13][14][15][16][17] However, all these applications have used the hAM as an acellular material, without taking advantage of the material's capacity to be seeded or used as a layered construct to speed and potentially enhance tissue regeneration. The hAM presents a number of desirable characteristics (advantageous for blood vessel regeneration and a wide range of tissue-engineering applications), including biocompatibility, biostability, noninflammatory, nontoxic, noncarcinogenic, nonimmunogenic, 17 vasoactivity, thromboresistance, 18 ability to remodel, 16 infection resistance, suture-holding capacity, 19 and its wide availability.…”

Time-dependent mechanical behavior of human amnion: Macroscopic and microscopic characterization

“…The amnion is considered to be the load-bearing layer of the FM [9] becoming the focus of mechanical investigations. In addition to its essential physiological function, it was also proposed as a promising candidate to be used as scaffold material for tissue engineering applications [10,11]. The mechanical response of the intact FM and of the separated amnion was investigated in uniaxial tensile tests [7,12,13,14,15,16,17,18], biaxial tensile tests [16,19], puncture tests [9,17,20,21,22,23,24] and inflation tests [3,25,26,27,28,29,30,31].…”

In VitroCharacterization of Patches of Human Mesenchymal Stromal Cells

“…Indeed, AM has been used to construct tissue-engineered products with amnion epithelial cells and amnion mesenchymal cells for prematurely ruptured fetal membrane repair, 15 with fibroblasts and keratinocytes for skin repair, 16 with limbal epithelial cells for corneal damage, 17 with chondrocytes for cartilage repair. 18 In all these studies, amniotic epithelium has been removed to use AM as a scaffold. However, protocols for decellularization of AM are long, complicated, required manual scrapping, and lack standardization.…”