Influence of Different Growth Factors on Chondrogenic Differentiation of Adipose-Derived Stem Cells in Polyurethane-Fibrin Composites

Introduction Chondrogenic differentiation of adipose-derived stem cells (ASCs) has proven to be feasible. To compensate for laryngeal palsy or cartilage defects after surgery or trauma using tissue engineering, a formable and stable scaffold material is mandatory. Methods ASCs were seeded in fibrin-polyurethane scaffolds and cultured in chondrogenic differentiation medium adding the growth factors TGF-□1, TGF-□3, and BMP-2 for up to 35 days. Results Histological examination showed acid glycosaminoglycans in the extracellular matrix in all groups. Immunofluorescence presented positive staining for collagen II, aggrecan, and SOX-9 in the TGF-□1–, TGF-□3–, and BMP-2-group. With Real-time PCR analyses, chondrogenic differentiation became apparent by the expression of the specific genes COL2A1 (collagen II), AGC 1 (aggrecan), and SOX-9, whereas collagen II expression was low in all groups compared to bone marrow-derived stem cells (BMSC) due to reduced chondrogenic ability. Conclusions These findings demonstrate the general ability of ASCs to differentiate into matrix-producing chondrocytes in fibrin-polyurethane scaffolds. However, further experiments are necessary to enhance this chondrogenic potential of ASCs seeded in fibrin-polyurethane scaffolds in order to produce a suitable regeneration method for treating cartilage defects or an implantable medialization material for vocal cord palsy.

Microscopic organisation of the oviducal gland of the holocephalan elephant fish, Callorhynchus milii

The study of chondrichthyan reproductive biology has a long history, but the structure and function of the holocephalan oviducal glands (OG) is poorly known; these organs are a vital component in the understanding of chondrichthyan life history. Histochemical techniques revealed that a fundamental zonation was evident in the OG of Callorhynchus milii, similar to most elasmobranchs. In sexually mature females, the following zones occurred (anterior to posterior): (1) club zone, periodic acid–Schiff positive (PAS+), indicating glycoprotein or any mucus substance containing neutral sugars, and Alcian blue positive, pH 2.5 (AB+), indicating the presence of sulfated and unsulfated acid glycosaminoglycans and sialoglycoproteins; (2) papillary zone (AB+); (3) baffle zone (PAS–, AB–); and (4) terminal zone (AB++). Using histological and histochemical techniques not used previously with the holocephalan group, we demonstrated that the structure and function of the OG zones were equivalent between oviparous elasmobranchs and C. milii, even though their final egg capsule morphologies differed. It was also evident that the club and papillary zones produce the egg jelly that surrounds the egg and the baffle zone formed the multilaminate egg capsule. Furthermore, the terminal zone had functions associated with sperm storage and the production of fine hairs that decorate the surface of the egg capsule.

Role of hyaluronic acid glycosaminoglycans in shear-induced endothelium-derived nitric oxide release

Endothelium-derived nitric oxide (NO) is synthesized in response to chemical and physical stimuli. Here, we investigated a possible role of the endothelial cell glycocalyx as a biomechanical sensor that triggers endothelial NO production by transmitting flow-related shear forces to the endothelial membrane. Isolated canine femoral arteries were perfused with a Krebs-Henseleit solution at a wide range of perfusion rates with and without pretreatment with hyaluronidase to degrade hyaluronic acid glycosaminoglycans within the glycocalyx layer. NO production rate was evaluated as the product of nitrite concentration in the perfusate and steady-state perfusion rate. The slope that correlates the linear relation between perfusion rate and NO production rate was taken as a measure for flow-induced NO production. Hyaluronidase treatment significantly decreased flow-induced NO production to 19 ± 9% of control (mean ± SD; P < 0.0001 vs. control; n = 11), whereas it did not affect acetylcholine-induced NO production (88 ± 17% of pretreatment level, P = not significant; n = 10). We conclude that hyaluronic acid glycosaminoglycans within the glycocalyx play a pivotal role in detecting and amplifying the shear force of flowing blood that triggers endothelium-derived NO production in isolated canine femoral arteries.