Cartilage tissue engineering using decellularized biomatrix hydrogel containing TGF-ß-loaded alginate microspheres in mechanically loaded bioreactor.

Physiochemical tissue inducers and mechanical stimulation are both efficient variables in cartilage tissue fabrication and regeneration. In the presence of biomolecules, decellularized extracellular matrix (ECM) may trigger and enhance stem cell proliferation and differentiation. Here, we investigated the controlled release of transforming growth factor beta (TGF-ß1) as an active mediator of mesenchymal stromal cells (MSCs) in a biocompatible scaffold and mechanical stimulation for cartilage tissue engineering. ECM-derived hydrogel with TGF-ß1-loaded alginate-based microspheres (MSs) was created to promote human MSC chondrogenic development. Ex vivo explants and a complicated multiaxial loading bioreactor replicated the physiological conditions. Hydrogels with/without MSs and TGF-ß1 were highly cytocompatible. MSCs in ECM-derived hydrogel containing TGF-ß1/MSs showed comparable chondrogenic gene expression levels as those hydrogels with TGF-ß1 added in culture media or those without TGF-ß1. However, constructs with TGF-ß1 directly added within the hydrogel had inferior properties under unloaded conditions. The ECM-derived hydrogel group including TGF-ß1/MSs under loading circumstances formed better cartilage matrix in an ex vivo osteochondral defect than control settings. This study demonstrates that controlled local delivery of TGF-ß1 using MSs and mechanical loading is essential for neocartilage formation by MSCs and that further optimization is needed to prevent MSC differentiation towards hypertrophy.

Production and evaluation of decellularized extracellular matrix hydrogel for cartilage regeneration derived from knee cartilage.

Cartilage tissue engineering is the interdisciplinary science that will help to improve cartilage afflictions, such as arthrosis, arthritis, or following joints traumatic injuries. In the present work, we developed an injectable hydrogel which derived from decellularized extracellular matrix of sheep cartilage. Successful decellularization was evaluated by measuring the DNA, glycosaminoglycans (GAG), collagen contents, and histological analyses. There was a minor difference in GAG and collagen contents among natural cartilage and decellularized tissue as well as ultimate hydrogel. Rheological analysis showed that the temperature and gelation time of prepared hydrogel were 37°C and between 5 and 7 min, respectively. Mechanical properties evaluation indicated a storage modulus of 20 kPa. The results show that prepared hydrogel possessed cell-friendly microenvironment as confirmed via calcein staining and MTT assay. Also, cells were able to proliferate which observed by H&E and alcian blue staining. Cell attachment and proliferation at the surface of the decellularized hydrogel was apparent by Scanning Electron Microscope (SEM) images and microphotographs. Furthermore, the cells embedded within the hydrogel were able to differentiate into chondrocyte with limited evidence of hypertrophy and osteogenesis in utilized cells which proved by SOX9, CoL2, ACAN, and also CoL1 and CoL10 gene expression levels. In summary, the results suggest that developed novel injectable hydrogel from decellularized cartilage could be utilized as a promising substrate for cartilage tissue engineering applications.

Correction to: Photobiomodulation with single and combination laser wavelengths on bone marrow mesenchymal stem cells: proliferation and differentiation to bone or cartilage.

In the originally published article, the name of the 3rd and 4th authors were labeled incorrectly. The correct names are Mohammadreza Baghaban Eslaminejad and Leila Taghiyar. Also, affiliation 4 has been corrected.

Photobiomodulation with single and combination laser wavelengths on bone marrow mesenchymal stem cells: proliferation and differentiation to bone or cartilage.

Tissue engineering aims to take advantage of the ability of undifferentiated stem cells to differentiate into multiple cell types to repair damaged tissue. Photobiomodulation uses either lasers or light-emitting diodes to promote stem cell proliferation and differentiation. The present study aimed to investigate single and dual combinations of laser wavelengths on mesenchymal stem cells (MSCs). MSCs were derived from rabbit iliac bone marrow. One control and eight laser irradiated groups were designated as Infrared (IR, 810 nm), Red (R, 660 nm), Green (G, 532 nm), Blue (B, 485 nm), IR-R, IR-B, R-G, and B-G. Irradiation was repeated daily for 21 days and cell proliferation, osseous, or cartilaginous differentiation was then measured. RT-PCR biomarkers were SOX9, aggrecan, COL 2, and COL 10 expression for cartilage and ALP, COL 1, and osteocalcin expression for bone. Cellular proliferation was increased in all irradiated groups except G. All cartilage markers were significantly increased by IR and IR-B except COL 10 which was suppressed by IR-B combination. ALP expression was highest in R and IR groups during osseous differentiation. ALP was decreased by combinations of IR with B and with R, and also by G alone. R and B-G groups showed stimulated COL 1 expression; however, COL 1 was suppressed in IR-B, IR-R, and G groups. IR significantly increased osteocalcin expression, but in B, B-G, and G groups it was reduced. Cartilage differentiation was stimulated by IR and IR-B laser irradiation. The effects of single or combined laser irradiation were not clear-cut on osseous differentiation. Stimulatory effects on osteogenesis were seen for R and IR lasers, while G laser had inhibitory effects.

Bone marrow mesenchymal stem cell and vein conduit on sciatic nerve repair in rats.

BACKGROUND: Peripheral nerve repair with sufficient functional recovery is an important issue in reconstructive surgery. Stem cells have attracted extensive research interest in recent years. OBJECTIVES: The purpose of this study was to compare the vein conduit technique, with and without the addition of mesenchymal stem cells in gap-less nerve injury repair in rats. MATERIALS AND METHODS: In this study, 36 Wistar rats were randomly allocated to three groups: In the first group, nerve repair was performed with simple neurorrhaphy (control group), in the second group, nerve repair was done with vein conduit over site (vein conduit group) and in the third group, bone marrow stem cells were instilled into the vein conduit (stem cell group) after nerve repair with vein conduit over site. Six weeks after the intervention, the sciatic function index, electrophysiological study and histological examination were performed. RESULTS: All animals tolerated the surgical procedures and survived well. The sciatic function index and latency were significantly improved in the vein conduit (P = 0.04 and 0.03, respectively) and stem cell group (P = 0.02 and 0.03, respectively) compared with the control group. No significant difference was observed in sciatic function and latency between the vein conduit and stem-cell groups. Moreover, histological analysis showed no significant difference in regenerative density between these two groups. CONCLUSIONS: The results of this study showed that the meticulous microsurgical nerve repair, which was performed using the vein tubulization induced significantly better sciatic nerve regeneration. However, the addition of bone marrow mesenchymal stem cell to vein conduit failed to promote any significant changes in regeneration outcome.