Ongoing foreign body reaction to subcutaneous implanted (heparin) modified Dacron in rats

Abstract

Dacron-containing heart valve repair devices trigger chronic inflammation characterized by the presence of activated macrophages, foreign body giant cells, and capsule formation. Upon blood contact, proinflammatory proteins adsorb to the material and provide a substrate for monocyte binding and differentiation. Various heparin-coated polymers have been shown to reduce adsorption of proinflammatory proteins in vitro and in vivo. In this study, the effect of knitted, heparin-coated Dacron on the foreign body reaction was tested subcutaneously in rats. We hypothesized that the anti-inflammatory effect of heparin would reduce monocyte recruitment and differentiation and therefore limit the inflammatory reaction. An ongoing foreign body reaction, characterized by the presence of foreign body giant cells and high vascularization, was observed in uncoated as well as (heparin-)coated Dacron at up to 180 days of implantation. Also, a thin capsule was formed around each material up to this time. In conclusion, although heparin coatings might have an effect on the acute inflammatory response, we were not able to show a difference between heparin-coated and uncoated Dacron after 180 days' implantation in rats. Further research needs to be conducted to assess the difference in proinflammatory protein adsorption between the tested materials and the effect this has on the long-term foreign body reaction.

High 18F-FDG Uptake in Synthetic Aortic Vascular Grafts on PET/CT in Symptomatic and Asymptomatic Patients

“…The basis for this 18 F-FDG accumulation may be the chronic inflammation known to occur on the surface of synthetic graft material (13)(14)(15). Although not statistically significant, the 18 F-FDG accumulation appears to be less prominent in endovascular grafts than in conventional grafts.…”

“…The chronic aseptic inflammation in synthetic graft material, mediated primarily by macrophages, fibroblasts, and foreign-body giant cells, constitutes a potential base for 18 F-FDG uptake, even a long time after the operation (13)(14)(15).…”

“…However, synthetic grafts provoke a chronic low-grade inflammation (13)(14)(15). This chronic inflammation constitutes a potential site for 18 F-FDG uptake and, therefore, a risk for false-positive results.…”

18F-FDG Uptake in Noninfected Prosthetic Vascular Grafts: Incidence, Patterns, and Changes over Time

“…18 F-FDG is also taken up by scar tissue and native vessels. Synthetic grafts often induce a foreign-body chronic low-grade inflammatory reaction, which can also exhibit increased 18 F-FDG activity, thus representing potential causes for false-positive results and erroneous interpretation of 18 F-FDG PET/CT studies (21)(22)(23). At present, there is only limited information regarding the incidence and patterns of 18 F-FDG uptake in noninfected vascular grafts, mainly in relationship to type and location of the implants.…”

Evaluation of biodegradable synthetic scaffold coated on arterial prostheses implanted in rat subcutaneous tissue

“…Instead of replacing or bypassing a segment of blood vessel, the specimens were implanted subcutaneously in rats. The rat subcutaneous model has been widely used to evaluate biocompatibility and biodegradation of synthetic polymers that will ultimately used in other locations such as nerve guidance channel [44] or blood contacting heart valve [45]. The results obtained in this experiment were expected to be useful as the initial step of an in vivo evaluation of synthetic scaffold within a vascular prosthetic structure.…”