An Assessment of Blood Vessel Remodeling of Nanofibrous Poly(ε-Caprolactone) Vascular Grafts in a Rat Animal Model

Abstract

The development of an ideal vascular prosthesis represents an important challenge in terms of the treatment of cardiovascular diseases with respect to which new materials are being considered that have produced promising results following testing in animal models. This study focuses on nanofibrous polycaprolactone-based grafts assessed by means of histological techniques 10 days and 6 months following suturing as a replacement for the rat aorta. A novel stereological approach for the assessment of cellular distribution within the graft thickness was developed. The cellularization of the thickness of the graft was found to be homogeneous after 10 days and to have changed after 6 months, at which time the majority of cells was discovered in the inner layer where the regeneration of the vessel wall was found to have occurred. Six months following implantation, the endothelialization of the graft lumen was complete, and no vasa vasorum were found to be present. Newly formed tissue resembling native elastic arteries with concentric layers composed of smooth muscle cells, collagen, and elastin was found in the implanted polycaprolactone-based grafts. Moreover, the inner layer of the graft was seen to have developed structural similarities to the regular aortic wall. The grafts appeared to be well tolerated, and no severe adverse reaction was recorded with the exception of one case of cartilaginous metaplasia close to the junctional suture.

Effective Needleless Electrospinning for the Production of Tubular Scaffolds

“…30 However, this does not necessarily apply in vivo, especially if accompanied by the use of biodegradable materials that support tissue regeneration. 27 As expected, the most significant difference between the two methods concerned their productivity, the investigation of which involved the measurement of the wall thickness and the weight yield of the samples at various electrospinning times (between 3 and 10 min). The results provided in Figure 6 show that the wall thickness, the weight yield, and the productivity increased with the time of fabrication in the case of both electrospinning methods.…”

“…Our previous research involved the changing of the inner diameter according to the needs of the respective study, e.g., for implantation in a rabbit carotid artery�an inner diameter of 2 mm 26 and for implantation in a rat abdominal aorta−an inner diameter of 1.65 mm. 27 The inner diameters required for glaucoma drainage devices are in the range of hundreds of micrometers with shorter lengths of up to 10 mm. 6 Peripheral nerve conduits are of comparable dimensions, i.e., inner diameters of units of micrometers and lengths of up to units of centimeters.…”

“…With respect to both electrospinning methods, the inner diameter can be easily changed via the use of a rotating rod with a different inner diameter. Our previous research involved the changing of the inner diameter according to the needs of the respective study, e.g., for implantation in a rabbit carotid arteryan inner diameter of 2 mm and for implantation in a rat abdominal aorta–an inner diameter of 1.65 mm . The inner diameters required for glaucoma drainage devices are in the range of hundreds of micrometers with shorter lengths of up to 10 mm .…”

“…Generally, the pore sizes of electrospun materials are insufficient for cell penetration in vitro . However, this does not necessarily apply in vivo, especially if accompanied by the use of biodegradable materials that support tissue regeneration …”

Remote Outcomes with Poly-ε-Caprolactone Aortic Grafts in Rats

“…One of the most common ways of polymeric vascular scaffold fabrication is electrospinning. This technology, based on the influence of a high voltage electric field on a stream of a conductive solution or melt (Figure S1), is the easiest way to produce non-woven nanofiber scaffolds with an adjustable fiber diameter, network pattern, porosity, and shape [17][18][19]. This allows the obtaining of sutureless tubular grafts with the desired physical properties and ultrastructure suitable for cell migration and graft vitalization [20][21][22][23][24].…”