Performance of marrow stromal cell-seeded small-caliber multilayered vascular graft in a senescent sheep model

Abstract

Failure of small-caliber grafts, used as bypass or reconstructive grafts in cardiovascular treatments, is often caused by thrombosis and stenosis. We have developed a multilayered, compliant graft with an electrospun heparin-encapsulated core and collagen-chitosan shell. Herein, the performances of acellular and cell-seeded grafts were evaluated in adult sheep for preclinical assessment. Allogeneic ovine marrow stroma cells (MSCs) were uniformly attached to the lumen of cell-seeded grafts. Interposition grafts were used for carotid arteries. Four grafts were tested for each type. Upon implantation, all grafts successfully restored perfusion and rhythmically deformed under pulsatile arterial flow. Weekly ultrasonography and Doppler revealed that all grafts remained patent for perfusion during the course of one-month study. No formation of blood clots or other complications were found. The diameter of graft lumen did not vary significantly over the time or with the graft type, while narrowing at anastomosis and significant thickening of graft wall were found in both types of grafts. More significant neotissue formation was found at anastomotic sections of acellular controls compared to cell-seeded grafts. Results from histological and immunofluorescent analyses revealed moderate intimal hyperplasia (IH) at anastomosis. When compared to cell-seeded grafts, acellular controls presented thicker IH composed of α-smooth muscle actin positive cells and ground substances, which correlated with reduced and more disturbing flow. IH was thickest at anastomosis and tapered off to a minimum in the mid-section. Few PECAM-positive cells appeared on cell-seeded grafts but not acellular controls. Additionally, lesser graft thickening was found in cell-seed grafts, which might be associated with the function of stromal cells in altering the fibrotic process during tissue repair. Results suggest that MSCs held the potential to reduce hyperplasia and improve healing in an aged, large animal model for vascular grafting.

Comparative Evaluation on Impacts of Fibronectin, Heparin–Chitosan, and Albumin Coating of Bacterial Nanocellulose Small-Diameter Vascular Grafts on Endothelialization In Vitro

“…Thereby, heparin–chitosan-coated grafts would be a very interesting option for small-diameter vascular grafts, even if the continuous ingrowth of ECs from the anastomic region could be impaired. It is known that intimal hyperplasia caused by smooth muscle cells at the anastomosis is one of the causes for graft failure [ 109 , 110 ], and interestingly, Chupa et al found impaired proliferation and cell spread of smooth muscle cells on heparin–chitosan-modified surfaces [ 32 ], which is also confirmed by the findings of Clowes et al [ 111 ]. Thus, a heparin–chitosan coating could probably limit the intimal hyperplasia at the anastomosis to the native vessel, while promoting endothelialization with EPCs originating from the donor blood, thereby overcoming the disadvantage of reduced attachment of HSVECs.…”

Systematic Review of Tissue-Engineered Vascular Grafts

“…Each article analyzed in this review created its own TEVG, although there were certain materials that were commonly used, such as biodegradable polymers, or biological materials. Notably, some researchers used heparin in the design of TEVGs ( Jiang et al, 2016 ; Koobatian et al, 2016 ; Hu et al, 2017 ; Ju et al, 2017 ; Madhavan et al, 2018 ; Xu et al, 2018 ; Jin et al, 2019a ; Jin et al, 2019b ; Ran et al, 2019 ; Shi et al, 2019 ; Smith et al, 2019 ; Wang et al, 2019 ). The addition of heparin to materials prevents thrombosis and enhances biocompatibility ( Aslani et al, 2020 ).…”

Synthesis, Applications and Biological Impact of Nanocellulose

“…Hu et al immobilized reactive Co (III) salen species onto sCNCs to produce heterogeneous catalysts for the synthesis of cyclic carbonates from propylene oxide and CO 2 [109]. These catalysts achieved a near quantitative yield in 24 h at low CO 2 pressure of 0.1 MPa with demonstrated reusability in four reaction cycles.…”