Regenerative medicine of cornea by cell sheet engineering using temperature-responsive culture surfaces

Abstract

Recently, regenerative medicine has been focused on as next-generation definitive therapies for several diseases or injuries for which there are currently no effective treatments. These therapies have been rapidly developed through the effective fusion between different fields such as stem cell biology and biomaterials. So far, we have proposed "cell sheet engineering" through our core technology that simply applies alterations of the temperature which allows regulation of the attachment or detachment of living cells on the culture surfaces grafted with the temperature-responsive polymer "poly(N-isoproplyacrylamide)". This technology enables us to construct bioengineered sheet-like tissues, termed "cell sheets", without the need of using biodegradable scaffolds and protease treatments that are traditionally used. Therefore, our carrier-free cell sheets not only are independent of the issues observed in conventional methods, but also showed further advantages in the reconstruction of the corneal epithelium or endothelium (e.g. improvement of optical transparency and cell-cell interactions to host stroma in reconstructed tissues). Moreover, our approach does not have issues such as immune rejection or limited number of donors, due to the use of cell sheets derived from autologous limbal (in patients with unilateral disease) or oral mucosal epithelial cells (in patients with bilateral disorders). Indeed, we have successfully performed the clinical application for the reconstruction of ocular surfaces through the transplantation of our carrier-free corneal epithelial cell sheets, as evidenced by improved visual acuity as well as long-term maintenance of postoperative health conditions on ocular surfaces in all patients. We have also proposed a novel approach for the reconstruction of the corneal endothelium using corneal endothelial cell sheets by demonstrating its successful application. Thus, our cell sheet engineering technique provides a breakthrough in the field of regenerative medicine applied to the cornea. cell sheet, temperature-responsive, carrier-free Citation:Umemoto T, Yamato M, Nishida K, et al. Regenerative medicine of cornea by cell sheet engineering using temperature-responsive culture surfaces. Chin Sci Bull, 2013, 58: 43494356,

Bioengineered corneal epithelial cell sheet from mesenchymal stem cells—A functional alternative to limbal stem cells for ocular surface reconstruction

“…Thermoresponsive polymers fall into the class of “smart” polymer materials which respond to change in temperature by phase change due to the shift in the solvation state of the polymers caused by changes in inter and intramolecular hydrogen bonding. Poly( N ‐isopropylacrylamide) (pNIPAAm) is the most prominent candidate in this class and is widely utilized for various biomedical application (Nishida et al, ; Umemoto, Yamato, Nishida, & Okano, ). The other polymers in this class include poly( N , N ‐diethylacrylamide) (PDEAM), poly( N ‐vinyl caprolactam) (PVC), poly( N ‐ethyl oxazoline) (PEtOx), poly(methyl vinyl ether) (PMVE), and other poly(acrylic acid‐ co ‐acrylamide) systems (Gandhi, Paul, Sen, & Sen, ).…”

“…Cell sheet technique for corneal epithelial reconstruction has been successfully implemented in human patients using various other cell types including limbal epithelial cells, oral mucosal cells (Nishida et al, ; Umemoto et al, ) etc. Long term effects of this mesenchymal cell sheets in case of LSCD are warranted to identify the efficacy of MSCs in functional replacement of limbal stem cells in case of LSCD patients and their role in replenishing the stem cells pool.…”

Super macroporous poly(N‐isopropyl acrylamide) cryogel for separation purpose

“…Stimuli‐responsive or smart polymers have the ability to respond to environmental stimuli such as temperature, pH, ion, electric field, and magnetic field, which have attracted great attentions for applications in several fields as tissue engineering, enzyme immobilization, protein‐ligand recognition, drug delivery, and cell‐sheet technology . The most widely used temperature sensitive polymers are poly( N ‐isopropyl acrylamide) (p(NIPAM)), poly( N , N ‐diethyl acrylamide), and poly (t‐butyl acrylamide), and they all possess hydrophobic groups such as methyl, ethyl, and propyl groups along with amide hydrophilic group .…”

Decellularized human corneal stromal cell sheet as a novel matrix for ocular surface reconstruction

“…It was also used to reconstruct defects of the esophagus (Yamaguchi et al, 2017), middle cavity of the ear (Yamamoto et al, 2017), lung (Kanzaki, Takagi, Washio, Kokubo, & Yamato, 2017), periodontal tissue (Iwata et al, 2018), and the cornea (Nishida et al, 2004). For the cornea, this method has mostly been used for corneal epithelial cell and limbal epithelial stem cell transplantation in patients with unilateral stem cell deficiency (Umemoto, Yamato, Nishida, & Okano, 2013). Limitations of these cell sheets include the limited thickness and-if artificial polymers are used as carrier for cell sheet growth-that their surface can affect cell behavior (Chen, Yan, & Zheng, 2018) and therefore the quality of the cell sheet.…”