In Vitro Study of Human Immune Responses to Hyaluronic Acid Hydrogels, Recombinant Spidroins and Human Neural Progenitor Cells of Relevance to Spinal Cord Injury Repair.

Chenhong Lin,Jan Johansson,Åsa Ekblad-Nordberg,Chia-Chen Hsu,Hua Ye,Jakob Michaëlsson,Anna Rising,Anna Rising,Elisabet Åkesson,Erik Sundström,Cecilia Götherström

doi:10.3390/cells10071713

Chenhong Lin, Jan Johansson + Show 9 more

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https://doi.org/10.3390/cells10071713

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Abstract

Scaffolds of recombinant spider silk protein (spidroin) and hyaluronic acid (HA) hydrogel hold promise in combination with cell therapy for spinal cord injury. However, little is known concerning the human immune response to these biomaterials and grafted human neural stem/progenitor cells (hNPCs). Here, we analyzed short- and long-term in vitro activation of immune cells in human peripheral blood mononuclear cells (hPBMCs) cultured with/without recombinant spidroins, HA hydrogels, and/or allogeneic hNPCs to assess potential host–donor interactions. Viability, proliferation and phenotype of hPBMCs were analyzed using NucleoCounter and flow cytometry. hPBMC viability was confirmed after exposure to the different biomaterials. Short-term (15 h) co-cultures of hPBMCs with spidroins, but not with HA hydrogel, resulted in a significant increase in the proportion of activated CD69+ CD4+ T cells, CD8+ T cells, B cells and NK cells, which likely was caused by residual endotoxins from the Escherichia coli expression system. The observed spidroin-induced hPBMC activation was not altered by hNPCs. It is resource-effective to evaluate human compatibility of novel biomaterials early in development of the production process to, when necessary, make alterations to minimize rejection risk. Here, we present a method to evaluate biomaterials and hPBMC compatibility in conjunction with allogeneic human cells.

Highlights

In order to evaluate if any of the biomaterials applied were cytotoxic to the immune cells, the human peripheral blood mononuclear cells (hPBMCs) were exposed to the respective biomaterials
Cells (80.6% ± 11.0%, p = 0.0104) was significantly increased in the VN–NT2RepCT film group compared to the control with hPBMC, only, while we found no upregulation in the granular hyaluronic acid (HA) hydrogel group applying the same markers and conditions (Figure 2c,e,f)
We further studied if human neural stem/progenitor cells (hNPCs), alone, or encapsulated in bulk or granular HA hydrogels affected the proliferation of hPBMCs after co-culture in vitro for 5 d

Summary

Introduction

Spinal cord injury (SCI) disrupts spinal cord function due to primary neural cell loss, hemorrhage, ischemia and secondary processes such as excitotoxicity, inflammation, demyelination and apoptosis, causing further structural damage. SCI results in vulnerability to secondary complications such as pressure ulcers, pain, urinary tract infections or progressing myelomalacia [1,2]. The local spinal environment after an injury includes multiple obstacles and little support for regeneration [3]. Multiple biomaterials have been tested to support repair, modify and enhance regenerative cues in the microenvironment, and offer drug or cell delivery for regenerative purposes after SCI [4]. Biomaterials aimed to improve structural and functional outcome after SCI require features of regenerative support while presenting low cytotoxicity and high biocompatibility, with no or minor immune reactions

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