Creating tissue with intervertebral disc-like characteristics using gdf5 functionalized silk scaffolds and human mesenchymal stromal cells

For years, researchers have searched for a suitable biomaterial to regenerate the intervertebral disc (IVD). A promising candidate is silk, as there have been several approaches in the past where silk fibroin was used to repair the IVD’s nucleus pulposus (NP) and annulus fibrosus (AF). However, to date, nobody has attempted to recreate IVD tissue with dimensions and cell densities comparable to a human IVD using silk and human mesenchymal stromal cells (MSC). Therefore, silk scaffolds were produced from Bombyx mori yarn. To mimic the AF, the yarn was embroidered into a ring-like structure or patch. To mimic the NP, fibre-additive manufacturing was applied to create highly porous constructs. Half of the NP scaffolds were functionalized with the growth differentiation factor 5 (GDF5). The scaffolds were seeded with MSCs from five human donors in a density of one-third of the density found in the human IVD and cultured for 7, 14 or 21 days in transforming growth factor β1 (TGF-β1)-enriched medium. All scaffolds were biocompatible as cell numbers increased by a factor 4-5. Furthermore, the scaffolds generally showed an anabolic phenotype, which was positively influenced by GDF5, and tissue-like characteristics were promoted based on the scaffolds’ morphology. In conclusion, the here proposed silk scaffolds showed IVD-like characteristics with a size and cell density comparable to human IVD tissue

Focal neuromyotonia: do I love you?

We present a rare case of focal neuromyotonia in a 73-year-old woman with a follow up of 5years. The clinical picture showed a fixed contraction of the 3rd and 4th finger of the left hand. Similar to other published cases, our patient suffered from COPD and was treated with beta-2-sympathomimetics. This clinical picture shows a rare but rather salient differential diagnosis of Dupuytren's contracture. EMG of the affected muscles may yield a diagnosis and prevent the patient from a long and ineffective treatment "odyssey

Bovine coccygeal intervertebral discs contain multipotent Tie2+ cells which can differentiate into osteogenic and adipogenic lineages

Question: The intervertebral disc (IVD) has a limited regenerative potential and low back pain represents a leading cause of disability [1]. IVD repair strategies require an appropriate cell source that is able to regenerate the damaged tissue such as progenitor stem cells. Recently, progenitor cells that are positive for the angiopoietin re- ceptor (Tie2) in the nucleus pulposus were identified [2]. Here we isolated primary cells from bovine IVD and sorted bovine nucleus pulposus progenitor cells (NPPC) for the marker Tie2. Furthermorewe tested whether Tie2 expressing cells can differentiate into os- teogenic and adipogenic lineages in vitro. Methods: NP cells were obtained from 1 year old bovine tails by sequential digestion with pronase for 1 h and collagenase over- night. Sorted Tie2- and Tie2+ cells were cultured in osteogenic and adipogenic medium for 3 weeks. The formed cell layers from both subpopulations were stained for calcium deposition and fat droplets. Colony forming units were prepared for both cell sus- pensions in methylcellulose-based medium and formed colonies ([10 cells) were analyzed macroscopically after 8 days. Results: After 3 weeks of culture, sorted Tie2+ cells were able to differentiate into osteocytes and adipocytes as characterized by cal- cium deposition and fat droplet formation. By contrast, Tie2- cells generated a weak staining for calcium and no fat droplets were ob- tained (Fig. 1). Sorted Tie2- and Tie2+ subpopulations of cells both formed colonies, however with different morphologies. The colonies formed from Tie2+ cells were spheroid in shape whereas those from Tie2- cells were spread and fibroblastic. Conclusion: Our data showed that Tie2+ cells of the nucleus pul- posus cells are progenitor-like cells that are able to differentiate into osteogenic and adipogenic lineages. Sorting of NPPC for Tie2 may represent a promising strategy with the potential to be used in the clinics for treatment of intervertebral disc damage. References 1. Freemont AJ (2009) The cellular pathobiology of the degenerate intervertebral disc and discogenic back pain. Rheumatology (Oxford) 48:5–10 2. Sakai D, Nakamura Y, Nakai T et al (2012) Exhaustion of nucleus pulposus progenitor cells with ageing and degeneration of the intervertebral disc. Nat Commun 3:1264 Acknowledgments: This project was funded by two projects of the Swiss National Science Foundation grant number #IZK0Z3_154384 and #310030_153411