Human Tissue Engineered Blood Vessel For Adult Arterial Revascularization

Full text available at:

http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1513140

Abstract available at (PubMed link):

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=16491087&query_hl=9&itool=pubmed_docsum

I chose this article for two main reasons. First of all, I believe that it would be helpful to other Bioengineering 115 students whose projects focus on tissue-engineered blood vessels. Besides that I think this article is a very comprehensive one. It thoroughly describes the technique for preparing and testing one particular type of the TEBV (tissue-engineered blood vessel).

In the experiment described human skin fibroblast cells were isolated from bypass patients and then cultured into sheets. Complex media supplemented with bovine serum, glutamine, penicillin, streptomycin and sodium ascorbate was used to feed the culture. As in natural blood vessels, three distinct cell layers (living adventitia, decellularized internal membrane and endothelium) were formed in the TEBV. Temporary Teflon®-coated stainless steel tube was used as a mechanical support during the formation of the first two layers (adventitia and IM (internal membrane)) and was removed later. When the vessel was ready, the natural conditions were simulated by subjecting the TEBV to the pulsating stream with the flow rate varying from 3ml/min to 150ml/min.

Mechanical testing was conducted to estimate (1) the burst pressure and (2) the suture retention strength of the vessels. Compliance was calculated based on the change in vessel diameter in response to increasing pressure (high resolution digital imaging was used to measure the vessel diameter).

The final phase of the experiment involved canine, nude rats and primate studies. In all trials immunosuppressive drugs were administered prior and following the introduction of the TEBV into the body. Tissue fixation and histology at different time periods were used to examine the condition of the newly incorporated blood vessels. The analysis revealed successful tissue integration, vasa vasorum formation and cell accumulation on the luminal side of the IM. Furthermore, the shape and size of the TEBV was approximately unchanged and proteoglycan expression was suppressed. This is indicative of the relative success of the preclinical trials.

In the end, authors suggest that if clinical trials of the TEBV prove successful further research should focus on decreasing time for the vessel production and other applications of allogeneic TEBVs.