3D bioprinting patient-derived induced pluripotent stem cell models of Alzheimer’s disease using a smart bioink

Abstract

Background Alzheimer’s disease (AD), a progressive neurodegenerative disorder, is becoming increasingly prevalent as our population ages. It is characterized by the buildup of amyloid beta plaques and neurofibrillary tangles containing hyperphosphorylated-tau. The current treatments for AD do not prevent the long-term progression of the disease and pre-clinical models often do not accurately represent its complexity. Bioprinting combines cells and biomaterials to create 3D structures that replicate the native tissue environment and can be used as a tool in disease modeling or drug screening. Methods This work differentiated both healthy and diseased patient–derived human induced pluripotent stems cells (hiPSCs) into neural progenitor cells (NPCs) that were bioprinted using the Aspect RX1 microfluidic printer into dome-shaped constructs. The combination of cells, bioink, and puromorphamine (puro)-releasing microspheres were used to mimic the in vivo environment and direct the differentiation of the NPCs into basal forebrain-resembling cholinergic neurons (BFCN). These tissue models were then characterized for cell viability, immunocytochemistry, and electrophysiology to evaluate their functionality and physiology for use as disease-specific neural models. Results Tissue models were successfully bioprinted and the cells were viable for analysis after 30- and 45-day cultures. The neuronal and cholinergic markers β-tubulin III (Tuj1), forkhead box G1 (FOXG1), and choline acetyltransferase (ChAT) were identified as well as the AD markers amyloid beta and tau. Further, immature electrical activity was observed when the cells were excited with potassium chloride and acetylcholine. Conclusions This work shows the successful development of bioprinted tissue models incorporating patient derived hiPSCs. Such models can potentially be used as a tool to screen promising drug candidates for treating AD. Further, this model could be used to increase the understanding of AD progression. The use of patient derived cells also shows the potential of this model for use in personalized medicine applications.

Leveraging Biomaterial Platforms to Study Aging-Related Neural and Muscular Degeneration

“…Other studies have also confirmed the suitability of this technique to generate models of Alzheimer's and Parkinson's disease. Benwood et al differentiated healthy and patient-derived iPSCs into NPCs, and incorporated these cells into dome-shaped constructs that promoted the differentiation of NPCs into basal forebrainresembling cholinergic neurons (BFCN), the first cell type affected in the progression of Alzheimer's disease [186]. With regard to the application of this technology in the production of models of Parkinson's disease, Abdelrahman et al reported the fabrication of a peptide-based model that maintained the activity of encapsulated dopaminergic neurons for more than one month.…”

A review on biopolymer-based bioinks for 3D bioprinting

“…44 Various cell types have been previously used in 3D bioprinting, and Table 3 below shows a summary of the some of the typically used cells and bioinks in relation to its target tissue model. [45][46][47][48][49][50][51][52][53] Bioink selection 3D bioprinting depends significantly on bioinks, biomaterials, and cells for generating 3D cultures, with these bioinks necessitating functionality and biocompatibility to replicate the properties of living tissues. 10 In selecting the appropriate bioink for 3D bioprinting, it is essential to be familiar with their general functions, which are typically categorized into four: structural, functional, sacrificial, and support.…”

“…distilled water, ammonium hydroxide solution, lithium bromide solution, RPMI 1640 medium, deionized water, McCoy's 5A medium) following manufacturer's instructions. [46][47][48][49][50][51][52][53][54][55][56][57][58][59][60][61][62][63][64] Afterwards, if the bioink is multicomponent, an additional material is mixed into the solution to obtain the target concentration. 59,61 Generally, multicomponent bio-inks are favored over single biomaterial-based bioinks because they can maintain maximal cell viability by mitigating the varying toxic effects each biomaterial may have on different cells.…”

“…Summary of commonly used cells and bioinks in various tissue models[45][46][47][48][49][50][51][52][53] …”