Three-dimensional culture of human nucleus pulposus cells in fibrin clot: comparisons on cellular proliferation and matrix synthesis with cells in alginate

Chondrogenesis of mesenchymal stromal cells on the 3D printed polycaprolactone/fibrin/decellular cartilage matrix hybrid scaffolds in the presence of piascledine

Nowadays, cartilage tissue engineering (CTE) is considered important due to lack of repair of cartilaginous lesions and the absence of appropriate methods for treatment. In this study, polycaprolactone (PCL) scaffolds were fabricated by three-dimensional (3D) printing and were then coated with fibrin (F) and acellular solubilized extracellular matrix (ECM). After extracting adipose-derived stem cells (ADSCs), 3D-printed scaffolds were characterized and compared to hydrogel groups. After inducing the chondrogenic differentiation in the presence of Piascledine and comparing it with TGF-β3 for 28 days, the expression of genes involved in chondrogenesis (AGG, COLII) and the expression of the hypertrophic gene (COLX) were examined by real-time PCR. The expression of proteins COLII and COLX was also determined by immunohistochemistry. Glycosaminoglycan was measured by toluidine blue staining. 3D-printed scaffolds clearly improved cell proliferation, viability, water absorption and compressive strength compared to the hydrogel groups. Moreover, the use of compounds such as ECM and Piascledine in the process of ADSCs chondrogenesis induction increased cartilage-specific markers and decreased the hypertrophic marker compared to TGF-β3. In Piascledine groups, the expression of COLL II protein, COLL II and Aggrecan genes, and the amount of glycosaminoglycan showed a significant increase in the PCL/F/ECM compared to the PCL and PCL/F groups.

Differential effects of rat ADSCs encapsulation in fibrin matrix and combination delivery of BDNF and Gold nanoparticles on peripheral nerve regeneration

Background

Fibrin as an extracellular matrix feature like biocompatibility, creates a favorable environment for proliferation and migration of cells and it can act as a reservoir for storage and release of growth factors in tissue engineering.

Methods

In this study, the inner surface of electrospun poly (lactic-co-glycolic acid) (PLGA) nanofibrous conduit was biofunctionalized with laminin containing brain derived neurotrophic factor (BDNF) and gold nanoparticles in chitosan nanoparticle. The rats were randomly divided into five groups, including autograft group as the positive control, PLGA conduit coated by laminin and filled with DMEM/F12, PLGA conduit coated by laminin and filled with rat-adipose derived stem cells (r-ADSCs), PLGA conduit coated by laminin containing gold-chitosan nanoparticles (AuNPs-CNPs), BDNF-chitosan nanoparticles (BDNF-CNPs) and filled with r-ADSCs or filled with r-ADSCs suspended in fibrin matrix, and they were implanted into a 10 mm rat sciatic nerve gap. Eventually, axonal regeneration and functional recovery were assessed after 12 weeks.

Results

After 3 months post-surgery period, the results showed that in the PLGA conduit filled with r-ADSCs without fibrin matrix group, positive effects were obtained as compared to other implanted groups by increasing the sciatic functional index significantly (p < 0.05). In addition, the diameter nerve fibers had a significant difference mean in the PLGA conduit coated by laminin and conduit filled with r-ADSCs in fibrin matrix groups relative to the autograft group (p < 0.001). However, G-ratio and amplitude (AMP) results showed that fibrin matrix might have beneficial effects on nerve regeneration but, immunohistochemistry and real-time RT-PCR outcomes indicated that the implanted conduit which filled with r-ADSCs, with or without BDNF-CNPs and AuNPs-CNPs had significantly higher expression of S100 and MBP markers than other conduit implanted groups (p < 0.05).

Conclusions

It seems, in this study differential effects of fibrin matrix, could be interfered it with other factors thereby and further studies are required to determine the distinctive effects of fibrin matrix combination with other exogenous factors in peripheral nerve regeneration.

Cartilage Particles can Promote Chondrogenesis of Adipose-Derived Stromal Cells on Poly(ε-Caprolactone)/Fibrin Hybrid Constructs Prepared via Sandwich Model

Electrospun fibers have demonstrated a remarkable potential as a framework structure in the fabrication of cartilage tissue engineering (CTE) scaffolds. Various extracellular matrices have been incorporated into electrospun scaffolds to mimic and simulate the extracellular environment. The objective of this study was to fabricate hybrid constructs using composite electrospun scaffolds based on poly (ε-caprolactone) (PCL) and cartilage-derived matrix (CDM) and fibrin hydrogel to improve the viability and differentiation of human adipose-derived stromal cells (ADSCs) for CTE applications.Initially, PCL and PCL-CDM electrospun mats were fabricated. Fibrin/ ADSCs hydrogel were seeded on PCL- CDM mats and arranged layer-by-layer using sandwich technique. This method has been employed to increase cell seeding and infiltration efficiency through the entire mass of the scaffold. Real-time reverse-transcription polymerase chain reaction (RT- PCR), were performed to examine the expression of collagen types II and X, SOX9 and aggrecan. The production of glycosaminoglycan (GAG) was also tested in vitro by Toluidine blue stain and biochemical assay in the cultured scaffolds.The findings demonstrated that incorporation of CDM in PCL fibers results in improved cell viability. Hematoxylin and eosin staining showed that the sandwich method resulted in homogenous cell seeding within the scaffold. Overall, the RT- PCR, biochemical and histological results, showed that incorporation of the CDM into PCL/fibrin sandwich scaffolds stimulated ADSCs chondrogenesis and produced the products which increased expression of chondrogenic genes. It also, enhanced GAG synthesis compared to PCL/fibrin scaffolds.These findings suggest PCL-CDM/fibrin can be considered as an appropriate hybrid scaffold for CTE applications.

Chondrogenic activity of two herbal products; pomegranate fruit extract and avocado/soybean unsaponifiable

Background and purpose

Articular cartilage defects aren't repaired by itself. Numerous studies have been conducted in the area of cartilage tissue engineering and some of them considered herbal products. An attempt was made in this study to compare the effects of pomegranate fruit extract (PFE), avocado/soybean unsaponifiable (ASU), and their equal proportional mixture on the chondrogenesis of human adipose-derived stem cells (hADSCs).

Experimental approach

PFE was prepared through the percolation method. ASU powder was dissolved in ethanol at 10 μg/mL concentration and was sterilized. The hADSCs first were isolated, expanded in monolayer culture and identified, and next seeded on fibrin scaffolds. The hADSCs/fibrin scaffolds were divided into 4 groups of control, ASU, PFE, and PFE+ ASU and subjected to in vitro induction for 2 weeks. The control group received chondrogenic medium, other groups received chondrogenic medium plus ASU, PFE, or PFE + ASU, respectively. The MTT assay was performed for cell viability evaluation, real-time polymerase chain reaction for expression of cartilage genes, and the toluidine blue, safranin-O, and immunohistochemistry for staining of the constructs.

Findings / Results

Cell viability, cartilage genes expression, matrix staining density, and collagen II protein levels in PFE samples were significantly higher than those of the other groups (P < 0.05). Histological assessments revealed more chondrogenic centers (P < 0.05) in the PFE group compared to the other groups.

Conclusion and implications

In this study, it was revealed that PFE can be considered as an induction factor for future chondrogenic studies.

Cartilage Tissue Engineering Via Icariin and Adipose-derived Stem Cells in Fibrin Scaffold

Background:

Nowadays, cartilage tissue engineering is the best candidate for regeneration of cartilage defects. This study evaluates the function of herbal extracts icariin (ICA), the major pharmacological constituent of herba Epimedium, compared with transforming growth factor β3 (TGFβ3) to prove its potential effect for cartilage tissue engineering.

Materials and Methods:

ICA, TGFβ3, and TGFβ3 + ICA were added fibrin-cell constructions derived from adipose tissue stem cells. After 14 days, cell viability analyzed by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H- tetrazolium bromide assay and the expression of cartilage genes was evaluated with real-time polymerase chain reaction (RT-PCR).

Results:

The results showed ICA, TGFβ3, and TGFβ3 + ICA increased the rate of proliferation and viability of cells; but there were no significant differences between them (P > 0.05). Furthermore, quantitative RT-PCR analysis demonstrated that cooperation of ICA with TGFβ3 showed a better effect in expression of cartilaginous specific genes and increased Sox9, type II collagen, and aggrecan expression significantly. Furthermore, the results of the expression of type I and X collagens revealed that TGFβ3 increased the expression of them (P < 0.01); However, treatment with ICA + TGFβ3 down regulated the expression of these genes significantly.

Conclusion:

The results indicated ICA could be a potential factor for chondrogenesis and in cooperation with TGFβ3 could reduce its hypertrophic effects and it is a promising factor for cartilage tissue engineering.

Evaluation of Electrospun Nanofiber-Anchored Silicone for the Degenerative Intervertebral Disc

The nucleus pulposus (NP) substitution by polymeric gel is one of the promising techniques for the repair of the degenerative intervertebral disc (IVD). Silicone gel is one of the potential candidates for a NP replacement material. Electrospun fiber anchorage to silicone disc, referred as ENAS disc, may not only improve the biomechanical performances of the gel but it can also improve restoration capability of the gel, which is unknown. This study successfully produced a novel process to anchor any size and shape of NP gel with electrospun fiber mesh. Viscoelastic properties of silicone and ENAS disc were measured using standard experimental techniques and compared with the native tissue properties. Ex vivo mechanical tests were conducted on ENAS disc-implanted rabbit tails to the compare the mechanical stability between intact and ENAS implanted spines. This study found that viscoelastic properties of ENAS disc are higher than silicone disc and comparable to the viscoelastic properties of human NP. The ex vivo studies found that the ENAS disc restore the mechanical functionality of rabbit tail spine, after discectomy of native NP and replacing the NP by ENAS disc. Therefore, the PCL ENF mesh anchoring technique to a NP implant can have clinical potential.

Ex vivo observation of human nucleus pulposus chondrocytes isolated from degenerated intervertebral discs

Study Design

We performed an ex vivo study to observe cell morphology and viability of human nucleus pulposus (NP) chondrocytes isolated from degenerated intervertebral discs (IVD).

Purpose

To better understand the biological behavior of NP chondrocytes in monolayer cultures.

Overview of Literature

Biological repair of IVDs by cell-based therapy has been shown to be feasible in clinical trials. As one of the most promising transplanting seeds, how the isolated NP chondrocytes behavior ex vivo has not been fully understood.

Methods

Human NP chondrocytes were harvested from 20 degenerated IVDs and cultured in monolayers. Histological and immunochemistry staining was used to detect cell morphology change. Cell viability was studied by analyzing cell cycle distribution and apoptotic rate in the primary and subculuted cells.

Results

The round or polygonal primary NP chondrocytes had an average adherence time of 7 days and took nearly 31 days to reach 95% confluence. The spindle-shaped P1 NP chondrocytes increased growth kinetics and took about 12 hours to adhere and 6.6 days to get 95% confluent. Immunochemistry staining of collagen II was positive in the cell cytoplasm. Nearly 90% of the confluent NP chondrocytes stayed in G1 phase while 16% underwent apoptosis. No significant difference of the collagen II expression, cell cycle distribution or the apoptosis indices were detected between the primary and subcultured NP chondrocytes.

Conclusions

Human NP chondrocytes undergo significant morphological change in monolayer cultures. Cell cycle distribution pattern and apoptosis index of the cutured NP chondrocytes potentially influence their clinical transplantation or laboratory use.