The Effect of Fluid Shear Stress on Chondrocytes in Endochondral Ossification

Tad is doing his PhD proposal today and that is the title. I can't really answer any other questions about it. He practiced for me last night and I now have no doubt in my mind that he is smarter than me. In this field anyway. But the last month has been very hard as he has been so busy getting it ready and he has had very little sleep, so hopefully today it will all pay off. Whether it goes well or not though, I am just going to be glad its over! We have been waiting for this day for quite some time. We are hoping just two years more and he will be finished. If you are really interested, you can ask him more, but here is a random slide and some paragraphs I stole from his paper.

Figure 6. Inorganic Phosphate and 24, 25(OH)₂D₃ cause an apparent increase in the levels of collagen II production when compared to the untreated control on day 11 post confluence. This, therefore, confirms that the ATDC5 cells exhibited a chondrogenic phenotype. The negative control was not treated with the primary antibody as a control for possible nonspecific binding of the secondary antibody.

The overall goal of this project is to contribute to the understanding of how fluid shear stress effects the differentiation of chondrocytes in an endochondral ossification pathway. A better understanding in this area will contribute to the basic understanding of the growth plate and developmental biology, as well as potentially progress tissue engineering strategies that involve the growth plate, bone fracture callus healing[6], osteochondral plugs[7], or even developmental biology of joints[2]. This project will focus on the general hypothesis that fluid shear stress modulates the differentiation resting zone chondrocytes.

Significance of the proposed work

This work is significant because understanding how mechanical stresses influence processes of natural development such as endochondral ossification offers better enabling tools to further develop clinical therapies. An individual will regulate endochondral ossification throughout much of his or her lifespan. It begins in the embryo with skeletal formation but occurs naturally throughout adolescence in the long bone growth plates, and perhaps throughout life in secondary growth plates like the temporal-mandibular joint. It also is a process that is utilized for healing large bone fractures via development of a cartilaginous callus. Incidents joint and cartilage injury are rising among young athletes in increasingly competitive sports programs, but little is understood how this over-exertion may affect their active growth plates. On the other spectrum, some youth suffer from an overly sedentary lifestyle and perhaps the lack of exercising their musculoskeletal system could influence their growth plate activity. The proper loading of a fracture callus could help improve bone healing. Osteochondral tissue engineering implants may be enhanced by understanding how to promote mechanically stimulated differentiation of the chondrocytes near the subchondral interface, like those found naturally in the growth plate. This study will directly address some of the basic fundamental challenges of these areas where basic understanding is lacking. The proposed studies are worthwhile to offer future benefits to these varied applications.

So while he has been grueling over that, I have finally finished SM's scrapbook. I know, it only took me two years! At least its done before the new baby comes. If you want to see it, you can view the PDF at baby book and put in my project ID # of 248592.