Aleksandra Policha

eNOS transfection of adipose‐derived stem cells yields bioactive nitric oxide production and improved results in vascular tissue engineering

This study evaluates the durability of a novel tissue engineered blood vessel (TEBV) created by seeding a natural vascular tissue scaffold (decellularized human saphenous vein allograft) with autologous adipose‐derived stem cells (ASC) differentiated into endothelial‐like cells. Previous work with this model revealed the graft to be thrombogenic, likely due to inadequate endothelial differentiation as evidenced by minimal production of nitric oxide (NO). To evaluate the importance of NO expression by the seeded cells, we created TEBV using autologous ASC transfected with the endothelial nitric oxide synthase (eNOS) gene to produce NO. We found that transfected ASC produced NO at levels similar to endothelial cell (EC) controls in vitro which was capable of causing vasorelaxation of aortic specimens ex vivo. TEBV (n = 5) created with NO‐producing ASC and implanted as interposition grafts within the aorta of rabbits remained patent for two months and demonstrated a non‐thrombogenic surface compared to unseeded controls (n = 5). Despite the xenograft nature of the scaffold, the TEBV structure remained well preserved in seeded grafts. In sum, this study demonstrates that upregulation of NO expression within adult stem cells differentiated towards an endothelial‐like lineage imparts a non‐thrombogenic phenotype and highlights the importance of NO production by cells to be used as endothelial cell substitutes in vascular tissue engineering applications. Copyright

Autologous human plasma in stem cell culture and cryopreservation in the creation of a tissue-engineered vascular graft

OBJECTIVE Previous work demonstrated the effectiveness of autologous adipose-derived stem cells (ASCs) as endothelial cell (EC) substitutes in vascular tissue engineering. We further this work toward clinical translation by evaluating ASC function after (1) replacement of fetal bovine serum (FBS) with autologous human plasma (HP) in culture and (2) cryopreservation. METHODS Human ASCs and plasma, isolated from periumbilical fat and peripheral blood, respectively, were collected from the same donors. ASCs were differentiated in endothelial growth medium supplemented with FBS (2%) vs HP (2%). Proliferation was measured by growth curves and MTT assay. Endothelial differentiation was measured by quantitative polymerase chain reaction, assessment of acetylated low-density lipoprotein uptake, and cord formation after plating on Matrigel (BD Biosciences, San Jose, Calif). Similar studies were conducted before and after cryopreservation of ASCs and included assessment of cell retention on the luminal surface of a vascular graft. RESULTS ASCs expanded in HP-supplemented medium showed (1) similar proliferation to FBS-cultured ASCs, (2) consistent differentiation toward an EC lineage (increases in CD31, von Willebrand factor, and CD144 message; acetylated low-density lipoprotein uptake; and cord formation on Matrigel), and (3) retention on the luminal surface after seeding and subsequent flow conditioning. Cryopreservation did not significantly alter ASC viability, proliferation, acquisition of endothelial characteristics, or retention after seeding onto a vascular graft. CONCLUSIONS This study suggests that (1) replacement of FBS with autologous HP--a step necessary for the translation of this technology into human use--does not significantly impair proliferation or endothelial differentiation of ASCs used as EC substitutes and (2) ASCs are tolerant to cryopreservation in terms of maintaining EC characteristics and retention on a vascular graft.

Coral reef aorta: case report and review of the literature.

Coral reef aorta (CRA) is a rare form of atherosclerosis that affects the paravisceral and pararenal aorta and its branches. Patients typically present with arterial insufficiency of the bowels, kidneys and lower extremities. The current mainstay of treatment is operative, typically involving transaortic endarterectomy. Herein, we describe a 54-year-old woman with incapacitating lower extremity claudication secondary to a paravisceral coral reef atheroma treated successfully with transaortic endarterectomy via a left retroperitoneal approach. In addition, we present a complete review of modern English literature on CRA.