Zukunftstechnologie Tissue-Engineering

Abstract

Limbal stem cells reside in a highly specialized complex microenvironment that is known as the stem cell niche, an anatomically protected region at the bottom of the Palisades of Vogt, where the stem cells are located and where their quiescence, proliferation and differentiation are maintained in balance. Besides the epithelial stem and progenitor cell clusters, the limbal niche comprises several types of supporting niche cells and a specific extracellular matrix mediating biochemical and biophysical signals. Stem cell-based tissue engineering aims to mimic the native stem cell niche and to present appropriate microenvironmental cues in a controlled and reproducible fashion in order to maintain stem cell function within the graft. Current therapeutic approaches for ex vivo expansion of limbal stem cells only take advantage of surrogate niches. However, new insights into the molecular composition of the limbal niche and innovative biosynthetic scaffolds have stimulated novel strategies for niche-driven stem cell cultivation. Promising experimental approaches include collagen-based organotypic coculture systems of limbal epithelial stem cells with their niche cells and biomimetic hydrogel platforms prefunctionalized with appropriate biomolecular and biophysical signals. Future translation of these novel regenerative strategies into clinical application is expected to improve long-term outcomes of limbal stem cell transplantation for ocular surface reconstruction.

Promises and Challenges of Cell-Based Therapies to Promote Lung Regeneration in Idiopathic Pulmonary Fibrosis

“…Stem cells and endogenous lung progenitor cells have been studied for many years as a therapy to promote tissue repair in chronic diseases because of their regenerative potential including their self-renewal capacity and ability to differentiate into different cell types of their tissue [ 140 ]. Remarkably, stem cell-based tissue engineering aims to mimic the native stem cell niche and maintain stem cell function within the graft by providing appropriate microenvironmental cues in a controlled and reproducible fashion to facilitate its application into human diseases including IPF [ 141 ].…”

Opening the Soul Window Manually: Limbal Tissue Scaffolds with Electrospun Polycaprolactone/Gelatin Nanocomposites

“…[ 1 ] More concretely, cultured limbal epithelial transplantation (CLET), [ 2 ] using tissue engineering techniques to extract a few limbal stem cells (LSCs) from the eye, and then culture and amplify LSC in vitro, proved to be an effective way to treat LSCD. [ 3 ] However, the existing two‐dimensional (2D) cell culture system is insufficient to mimic the limbal microenvironment, [ 4 ] and it is difficult to constitute a multilayer structure mimicking the limbus in vivo. [ 5 ] Compared with traditional 2D anchorage‐dependent cell culture methods, [ 6 ] 3‐dimensional (3D) culture system can better maintain the original characteristics of cells and facilitate their function in cell morphology, function, migration, and differentiation.…”