Flow Preservation of Umbilical Vein for Autologous Shunt and Cardiovascular Reconstruction

Abstract

Background: Synthetic graft materials are commonly used for shunts and cardiovascular reconstruction in neonates, but are prone to thrombosis and scarring. The umbilical vein is a potential source of autologous, endothelialized tissue for neonatal shunts and tissue reconstruction, but requires preservation before implantation.

Methods: Umbilical cords were collected in UW solution with antibiotics at 4°C until dissection. Umbilical vein segments were tested for burst pressure before and after 2 weeks of preservation. Umbilical veins segments were preserved under static or flow conditions at 4°C in UW solution with 5% human plasma lysate for 7 days. Veins were evaluated with histopathology, scanning electron microscopy, and platelet adhesion testing.

Results: Umbilical veins have no difference in burst pressure at harvest (n = 16) compared with 2 weeks of preservation (n = 11; 431 ± 229 versus 438 ± 244 mm Hg). After 1 week, static and flow-preserved veins showed viability of the vessel segments with endothelium staining positive for CD31, von Willebrand factor, and endothelial nitric oxide synthase. Scanning electron microscopy demonstrated preservation of normal endothelial morphology and flow alignment in the flow-preserved samples compared with cobblestone endothelial appearance and some endothelial cell loss in the static samples. Static samples had significantly more platelet adhesion than flow-preserved samples did.

Conclusions: Umbilical veins have adequate burst strength to function at neonatal systemic pressures. Preservation under flow conditions demonstrated normal endothelial and overall vascular morphology with less platelet adhesion compared with static samples. Preserved autologous umbilical veins are potential source for endothelialized shunts or cardiovascular repair tissue for neonates.

Fig 1.

(A, B) Bioreactor for flow preservation of 5-cm umbilical vein segments with 3 veins secured and preserved in flow conditions. (C, D) Lifeport transporter system with umbilical vein preserved under flow conditions within the Lifeport system.

Fig 2.

Hematoxylin and eosin staining of paraffin samples of (A, D) fresh samples, (B, E) static preservation at 7 days, and (C, F) flow preservation at 7 days. Movat’s staining of paraffin samples of (G) fresh, (H) static preservation at 7 days, and (I) flow preservation at 7 days. Scale bar = 250 μm.

Fig 3.

CD31 staining of paraffin samples of (A, D) fresh samples, (B, E) static preservation at 7 days, and (C, F) flow preservation at 7 days. vWF staining of frozen samples of (G) fresh, (H) static preservation at 7 days, and (I) flow preservation at 7 days. Scale bar = 250 μm.

Fig 4.

Endothelial NOS staining of frozen samples of (A) fresh, (B) static preservation at 7 days, and (C) flow preservation at 7 days. Intercellular adhesion molecule staining of frozen samples of (D) fresh, (E) static preservation at 7 days, and (F) flow preservation at 7 days. Vascular cell adhesion molecule staining of frozen samples of (G) fresh, (H) static preservation at 7 days, and (I) flow preservation at 7 days. Scale bar = 250 μm.

Fig 5.

Platelet adhesion test results of (A–C) collagen control samples, (D–F) static preservation 7-day samples, and (G–I) flow preservation 7-day samples, and (J) graph of counts of platelet adhesion testing. Scale bar = 500 μm.

Fig 6.

Scanning electron microscopy analysis of (A, D) fresh samples, (B, E) static preservation at 7 days, and (C, F) flow preservation at 7 days.

Fig 7.

The α-smooth muscle actin staining for smooth muscle cells with DAPI counterstain of verification samples (A) at delivery and (B) after 7 days of preservation. CD31 staining for endothelium with DAPI counterstain of verification samples(C) at delivery and (D) after 7 days of flow preservation. Scale bar = 50 μm.