Investigation of biofunctionalized electrospunscaffolds for kidney tissue engineering

Abstract

Kidney disease is a highly prevalent condition among the world population amounting to almost 1 in 10 people. The mortality rate associated with it has risen over the past two decades affecting mostly low- and middle-income countries due to the privation in their health system. It brings a heavy burden to society not only in terms of human loss but also economic cost for which a great deal of the healthcare budget of countries is directed to the treatment of kidney diseases. Currently, there is no cure but limited treatment options for chronic kidney disease including dialysis and transplantation. These replacement therapies offer help only to relieve the symptoms and to prevent the disease from getting worse. Longterm drug therapy given alongside these is another problem since it leads to drug-induced toxicity which is responsible for up to 20% of renal failure. The paucity of current treatment options prompts new solutions to these problems.

Tissue engineering emerges as a new avenue to create a niche for cells so that new ways to understand disease progression and enhance renal replacement therapies can be found. It brings scaffolds, cells and signals to a common point to provide a functional membrane. This PhD focuses on fabricating biofunctionalized scaffolds for kidney tissue engineering (KTE). Three chapters have been presented in this thesis to improve the bioactivity of polymeric electrospun scaffolds through different methodologies and biomolecules incorporated. In the first chapter, the effect of laminin addition into polycaprolactone (PCL) scaffolds with two methods and concentrations was investigated. In the second chapter, the effect of the addition of rat kidney extracellular matrix (rkECM) in emulsion form was investigated. In the last chapter, the effect of human kidney ECM (hkECM) with direct blending was investigated.

Decellularization of rat and human kidneys was performed in different settings, both yielded successful outcomes confirmed by quantitative and qualitative analyses. Electrospun scaffolds were manufactured with similar morphologies to test only the desired variable and interpret the results independently. All scaffolds have been characterized for physical, mechanical and chemical properties before seeding with human kidney epithelial cells (RC- 124). Cell seeded scaffolds were then cultured for 2 weeks, and assessed through proliferation, immunohistochemistry and gene expression. Results from laminin incorporation demonstrated that the type of inclusion has an impact on the cell attachment, DNA content and transcriptional activity. Rat kidney ECM blended scaffolds were successfully produced with emulsion electrospinning, showing the potential of the technique to be used with different bioactive agents. Human kidney ECM supported cell survival and functions throughout the culture period. This work proposes that the composition of electrospun scaffolds has a measurable effect on cell culture, and hybrid scaffolds have potential as a platform in kidney tissue engineering.