surgical-technique-for-implantation-tissue-engineered-vascular-grafts

Surgical Technique for the Implantation of Tissue Engineered Vascular Grafts and Subsequent <em>In Vivo </em>Monitoring

The development of Tissue Engineered Vessels (TEVs) is advanced by the ability to routinely and effectively implant TEVs (4-5 mm in diameter) into a large ...

State University of New York Buffalo School of Medicine

We examined the effects of senescence on the proliferation and leiomyogenic differentiation potential of mesenchymal stem cells (MSCs) isolated from bone marrow (BM-MSCs) or hair follicles (HF-MSCs). To this end, we compared ovine HF-MSCs and BM-MSCs in terms of their proliferation and differentiation potential to the smooth muscle cell lineage. We discovered that HF-MSCs are less susceptible to culture senescence compared with BM-MSCs. We hypothesized that application of mechanical forces may enhance the contractility and mechanical properties of vascular constructs prepared from senescent MSCs. Interestingly, HF-MSCs and BM-MSCs responded differently to changes in the mechanical microenvironment, suggesting that despite phenotypic similarities, MSCs from different anatomic locations may activate different pathways in response to the same microenvironmental factors. In turn, this may also suggest that cell-based tissue regeneration approaches may need to be tailored to the stem cell origin, donor age, and culture time for optimal results.

Differential Effects of Culture Senescence and Mechanical Stimulation on the Proliferation and Leiomyogenic Differentiation of MSC from Different Sources: Implications for Engineering Vascular Grafts.

We demonstrate the ability of immobilized vascular endothelial growth factor (VEGF) to capture endothelial cells (EC) with high specificity under fluid flow. To this end, we engineered a surface consisting of heparin bound to poly-l-lysine to permit immobilization of VEGF through the C-terminal heparin-binding domain. The immobilized growth factor retained its biological activity as shown by proliferation of EC and prolonged activation of KDR signaling. Using a microfluidic device we assessed the ability to capture EC under a range of shear stresses from low (0.5 dyne/cm(2)) to physiological (15 dyne/cm(2)). Capture was significant for all shear stresses tested. Immobilized VEGF was highly selective for EC as evidenced by significant capture of human umbilical vein and ovine pulmonary artery EC but no capture of human dermal fibroblasts, human hair follicle derived mesenchymal stem cells, or mouse fibroblasts. Further, VEGF could capture EC from mixtures with non-EC under low and high shear conditions as well as from complex fluids like whole human blood under high shear. Our findings may have far reaching implications, as they suggest that VEGF could be used to promote endothelialization of vascular grafts or neovascularization of implanted tissues by rare but continuously circulating EC.

Article	Year
Differential Effects of Culture Senescence and Mechanical Stimulation on the Proliferation and Leiomyogenic Differentiation of MSC from Different Sources: Implications for Engineering Vascul... Tissue engineering. Part A\| PubMed ID: 25517657	2015
Capture of endothelial cells under flow using immobilized vascular endothelial growth factor. Biomaterials\| PubMed ID: 25771020	2015

Maxwell T. Koobatian

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