Scaffolds from surgically removed kidneys as a potential source of organ transplantation

Bioengineering strategies for restoring vision

Late-stage retinal degenerative disease involving photoreceptor loss can be treated by optogenetic therapy, cell transplantation and retinal prostheses. These approaches aim to restore light sensitivity to the retina as well as visual perception by integrating neuronal responses for transmission to the cortex. In age-related macular degeneration, some cell-based therapies also aim to restore photoreceptor-supporting tissue to prevent complete photoreceptor loss. In the earlier stages of degeneration, gene-replacement therapy could attenuate retinal-disease progression and reverse loss of function. And gene-editing strategies aim to correct the underlying genetic defects. In this Review, we highlight the most promising gene therapies, cell therapies and retinal prostheses for the treatment of retinal disease, discuss the benefits and drawbacks of each treatment strategy and the factors influencing whether functional tissue is reconstructed and repaired or replaced with an electronic device, and summarize upcoming technologies for enhancing the restoration of vision.

Renal bioengineering with scaffolds prepared from discarded human kidneys by human mesenchymal stem cells

AIMS

Regeneration of discarded human kidneys has been considered as an ideal approach to overcome organ shortage for the end-stage renal diseases (ESRDs). The aim of this study was to develop an effective method for preparation of kidney scaffolds that retain the matrix structure required for proliferation and importantly, differentiation of human adipose-derived mesenchymal stem cells (hAd-MSCs) into renal cells.

MAIN METHODS

we first compared two different methods using triton X-100 and sodium dodecyl sulfate (SDS) for human kidney decellularization; and characterized developed human renal extracellular matrix (ECM) scaffolds. Then, hAd-MSCs were seeded on human decellularized kidney scaffolds and cultured for up to 3 weeks. Next, viability, proliferation, and migration of seeded hAd-MSCs within the scaffolds, underwent histological and scanning electron microscopy (SEM) assessments. Moreover, differentiation of hAd-MSCs into kidney-specific cell types was examined using immunohistochemistry (IHC) staining and qRT-PCR.

KEY FINDINGS

Our results indicated that triton X-100 was a more effective detergent for decellularization of human kidneys compared with SDS. Moreover, attachment and proliferation of hAd-MSCs within the recellularized human kidney scaffolds, were confirmed. Seeded cells expressed epithelial and endothelial differentiation markers, and qRT-PCR results indicated increased expression of platelet and endothelial cell adhesion Molecule 1 (PECAM-1), paired box 2 (PAX2), and e-cadherine (E-CDH) as factors required for differentiation of hAd-MSCs into epithelial and endothelial cells.

SIGNIFICANCE

These observations indicate effectiveness of decellularization by triton X-100 to generate suitable human ECM renal scaffolds, which supported adhesion and proliferation of hAd-MSCs and could induce their differentiation towards a renal lineage.

Experimental Evaluation of Kidney Regeneration by Organ Scaffold Recellularization

The rising number of patients needing renal replacement therapy, alongside the significant clinical and economic limitations of current therapies, creates an imperative need for new strategies to treat kidney diseases. Kidney bioengineering through the production of acellular scaffolds and recellularization with stem cells is one potential strategy. While protocols for obtaining organ scaffolds have been developed successfully, scaffold recellularization is more challenging. We evaluated the potential of in vivo and in vitro kidney scaffold recellularization procedures. Our results show that acellular scaffolds implanted in rats cannot be repopulated with host cells, and in vitro recellularization is necessary. However, we obtained very limited and inconsistent cell seeding when using different infusion protocols, regardless of injection site. We also obtained experimental and theoretical data indicating that uniform cell delivery into the kidney scaffolds cannot be obtained using these infusion protocols, due to the permeability of the extracellular matrix of the scaffold. Our results highlight the major physical barriers that limit in vitro recellularization of acellular kidney scaffolds and the obstacles that must be investigated to effectively advance this strategy for regenerative medicine.