Ex-Vivo Stimulation of Adipose Stem Cells by Growth Factors and Fibrin-Hydrogel Assisted Delivery Strategies for Treating Nerve Gap-Injuries

Abstract

Peripheral nerve injuries often result in lifelong disabilities despite advanced surgical interventions, indicating the urgent clinical need for effective therapies. In order to improve the potency of adipose-derived stem cells (ASC) for nerve regeneration, the present study focused primarily on ex-vivo stimulation of ASC by using growth factors, i.e., nerve growth factor (NGF) or vascular endothelial growth factor (VEGF) and secondly on fibrin-hydrogel nerve conduits (FNC) assisted ASC delivery strategies, i.e., intramural vs. intraluminal loading. ASC were stimulated by NGF or VEGF for 3 days and the resulting secretome was subsequently evaluated in an in vitro axonal outgrowth assay. For the animal study, a 10 mm sciatic nerve gap-injury was created in rats and reconstructed using FNC loaded with ASC. Secretome derived from NGF-stimulated ASC promoted significant axonal outgrowth from the DRG-explants in comparison to all other conditions. Thus, NGF-stimulated ASC were further investigated in animals and found to enhance early nerve regeneration as evidenced by the increased number of β-Tubulin III+ axons. Notably, FNC assisted intramural delivery enabled the improvement of ASC’s therapeutic efficacy in comparison to the intraluminal delivery system. Thus, ex-vivo stimulation of ASC by NGF and FNC assisted intramural delivery may offer new options for developing effective therapies.

Modulation of Human Adipose Stem Cells’ Neurotrophic Capacity Using a Variety of Growth Factors for Neural Tissue Engineering Applications: Axonal Growth, Transcriptional, and Phosphoproteomic Analyses In Vitro

“…Nerve tissue engineering holds promise for developing a viable new strategy subjective to the availability of effective neurotrophic cell sources [ 68 ]. MSC derived from variety of tissues have been widely known to possess multilineage capacity and multifunctional potency [ 28 , 37 , 51 , 68 ]. The ability of these cells to support the trophic needs of the neuronal cells for survival, development, and plasticity can be defined as “neurotrophic capacity” within the context of functional multipotency of the stem cells.…”

“…Cell with improved trophic capacity for addressing the complex needs of severed nerves would circumvent the side effects associated with application of large number of exogenous factors [ 29 ]. ASC and SCLC were shown to support nerve regeneration by releasing a variety of biological factors with mitotic and neuritogenic activity, although neurotrophic capacity of ASC is still inferior to SC [ 51 ]. Growth factors and related receptors play key role in the SC lineage and their autocrine survival loop [ 52 ].…”

“…Interestingly, ASC were found to express most of the receptors for NTF [ 35 , 37 , 53 , 54 , 55 , 56 ] suggesting that ASC may operate like SC in response to NTF stimulation. Within this context, we recently demonstrated enhanced neurotrophic capacity of ASC in response to nerve growth factor (NGF) stimulation in vitro and in vivo [ 51 ].…”

“…Therefore, it is fundamental to understand the role of variety of NTF individually on the fate of ASC at cellular and molecular levels. However, studies elucidating the influence of NTF on ASC biology (neurotrophic capacity) are largely missing, thus there is a great need for shedding light on this key topic [ 51 ].…”

Stem Cell Bioprocessing and Manufacturing

“…In addition to the increasing demand for large-scale cell manufacturing protocols, there is a critical need to establish potency assays for stem cell therapy products and their derivatives. Katharina M. Prautsch and colleagues [ 7 ] developed a strategy to improve the potency of ASC for nerve regeneration through ex vivo stimulation of ASC with nerve growth factor (NGF). The authors found that the secretome from NGF-stimulated ASC promoted significant axonal outgrowth in an in vitro setting.…”