Metabolic Responses of Adipose-Derived Stem Cells in Collagen I Hydrogels

Abstract

Peripheral nerve injury affects approximately 44 in 1 million people in the United States every year and can lead to incomplete nerve recovery and loss of motor and sensory function. A significant amount of energy is required for nerve injury repair. A lack of energy allocation to the injury site hinders repair. Current treatments include hollow nerve guidance conduits, decellularized nerve grafts, and autografts. However, they are limited by factors such as donor site morbidity and sustained immunosuppressive treatments. Using three-dimensional collagen I hydrogels laden with adipose-derived stem cells (ASCs) can assist in neural regeneration. Three-dimensional collagen scaffolds aim to mimic the extracellular matrix, while ASCs encourage neural regeneration, providing a platform for nerve injury repair. This project investigated the metabolic activity of ASCs seeded in collagen I hydrogel scaffolds with varying topological properties—warm aligned, warm nonaligned, cold aligned, and cold nonaligned. Metabolic activity was assessed using alamarBlue, adenosine triphosphate (ATP), glutamine/glutamate, and glucose assays. Metabolic assays like alamarBlue showed 2.98% and 5.59% percent reduction values at 3 and 6 hours, respectively, at day 7 for warm stretched hydrogels. In comparison, cold stretched hydrogels exhibited values of 2.55% and 4.62% at the same time points. The ATP assay results showed a luminescence reading of 897,394 Relative Light Units (RLU) for warm nonstretched hydrogels at day 7. The glutamate assay showed a luminescence reading of 310,976.5 RLU for warm stretched hydrogels at day 7. Glucose showed a luminescence reading of 656,380.5 RLU for cold nonstretched hydrogels at day 7. The findings of this project demonstrated that ASC metabolism varies across scaffolds with different topological properties, contributing to a deeper understanding of the changes of ASC metabolism based on microenvironmental differences