Article
One-way Street Disc Degeneration? An Investigation of Hydrogel and Fibroblast Growth Factor 18 (FGF-18) for Intervertebral Disc Regeneration
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Authors
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Sonja Häckel
- Wirbelsäulenchirurgie, Dep. Orthopädie und Traumatologie, Inselspital, Universitätsspital Bern, Bern, Switzerland
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Zhen Li
- AO Forschungsinstitut, Biochemie & Zellbiologie, Davos, Switzerland
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Mona Zolfaghar
- Islamic Azad University, Pharmaceutical Sciences Branch, Teheran, Iran
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Avner Yayon
- procore-bio med ltd., Ness Ziona, Israel
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Sven Hoppe
- Wirbelsäulenchirurgie, Dep. Orthopädie und Traumatologie, Inselspital, Universitätsspital Bern, Bern, Switzerland
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Lorin Benneker
- Inselspital Bern, Department für Orthopädie und Unfallchirurgie, Universität Bern, Bern, Switzerland
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Mauro Alini
- AO Forschungsinstitut, Biochemie & Zellbiologie, Davos, Switzerland
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Sibylle Grad
- AO Forschungsinstitut, Biochemie & Zellbiologie, Davos, Switzerland
| Published: | October 22, 2019 |
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Outline
Text
Objectives: The intervertebral disc (IVD), has a low supply of nutrients and oxygen, and therefore a limited self-healing capacity. The healthy nucleus pulposus (NP) is rich in Collagen 2 (COL 2) and water binding proteoglycans like Aggrecan (ACAN). During disc degeneration, Collagen 1 (COL 1) is increasing in the NP tissue which leads to a more fibrous and resistant tissue. This degenerative process is still a one-way street, because treatment strategies focusing on biological regeneration of the IVD are still missing.
Therefore, we investigated a hyaluronic acid hydrogel (HA:FBG, RegenoGelTM), and the fibroblast growth factor 18 (FGF-18), which has been subject of clinical studies promoting cell differentiation and proliferation in cartilage tissue (which represents a similar situation as found in the avascular disc tissue).
The aims of the present work were to investigate the regenerative effect of
- 1.
- HA:FBG hydrogel, and
- 2.
- FGF-18 on human and bovine NP cells in vitro.
Methods: Healthy bovine NP cells (n=4, age 8-12 month) and human mildly degenerated NP cells (n=4, age 30-55 years, Pfirrmann grade 2-3) were cultured for 14 days in a Fibrinogen-Hyaluronic acid (Fibrin-HA) hydrogel (RegenoGelTM, provided by ProCore, Israel). Cells were stimulated by adding FGF-18 (1, 10, and 100 ng/ml) in the culture medium. At day 7 and day 14, gene expression was measured by real-time RT-PCR; Glycosaminoglycan (GAG) content in the gel and medium was evaluated by DMMB assay, and histology was performed by cryosection followed by safranin-o/fast green staining.
Results and conclusion:
- Aim (1): Both bovine and human NP cells, encapsulated in the HA:FBG hydrogel, showed a donor dependent up-regulation in gene expression for the anabolic marker COL 2 ([+]: 24x p<0.01 in human NP cells) and ACAN([+]: 13x, ns). Furthermore, an increase of glycosaminoglycans content in hydrogel over the time (p<0.001) was detected.
- Aim (2): No significant difference upon addition of FGF-18 were seen. In contrast to the biochemical analysis, histological samples revealed an increase in proteoglycan content in a dose dependent manner. This was more evident in bovine NP cells compared to the human NP cells.
Analysis showed that the Fibrin-HA hydrogel supports cell function in already degenerated human disc cells. By adding FGF-18, we could not see a significant improvement of this effect at the tested experimental conditions. More pronounced matrix synthesis may be observed in longer term studies.
The hydrogel might be a promising treatment option and could also be loaded with other drugs, with or without FGF-18.
