Background: Many studies have been performed in order to model abdominal aortic aneurysm (AAA) in an experimental animal, most commonly in small laboratory animals. In our study, we tried to find the best AAA model in a pig by using various mechanical and enzymatic mechanisms. Methods: Twenty-two pigs were operated on. We combined 3 mechanisms of creating an AAA, using an intraluminal infusion of porcine pancreatic elastase into the abdominal aortic segment, application of plastic cuff below the renal arteries causing turbulent blood flow, and inserting a patch into the longitudinal aortotomy. Results: We found different results in different groups according to the mechanisms used. In group A, with a combination of the intraluminal elastase infusion and application of a stenosing cuff, AAA developed in all 7 animals (100%). In this group, we also found the largest histological changes in the abdominal aorta samples. Conclusion: The use of intraluminal pancreatic elastase infusion, together with increased turbulent flow caused by the stenosing cuff, seems to be the best model of AAA in pigs. This model is suitable for further research in the etiopathology of AAA. In fact, it is the first successful approach to a large-caliber native aneurysm model.

The use of electrospun polymeric biodegradable materials for medical applications is becoming increasingly widespread. One of the most important parameters regarding the functionality of nanofiber scaffolds during implantation and the subsequent regeneration of damaged tissues concerns their stability and degradation behavior, both of which are influenced by a wide range of factors (the properties of the polymer and the polymer solution, the technological processing approach, the sterilization method, etc.). This study monitored the degradation of nanofibrous materials fabricated from degradable polyesters as a result of the sterilization method applied (ethylene oxide and gamma irradiation) and the solvent system used to prepare the spun polymer solution. Aliphatic polyesters PCL and PLCL were chosen for this study and selected with respect to the applicability and handling in the surgical setting of these nanofibrous materials for vascular bandaging. The results revealed that the choice of solvent system exerts a significant impact on degradation during sterilization, especially at higher gamma irradiation values. The subsequent enzyme-catalyzed degradation of the materials following sterilization indicated that the choice of the sterilization method influenced the degradation behavior of the materials. Whereas wave-like degradation was evident concerning ethylene oxide sterilization, no such behavior was observed following gamma-irradiation sterilization. With concern for some of the tested materials, the results also indicated the potential for influencing the development of degradation within the bulk versus degradation from the surface of the material. Both the sterilization method and the choice of the spinning solvent system were found to impact degradation, which was observed to be most accelerated in the case of PLCL (L-lactide-co-caprolactone copolymer) electrospun from organic acids and subsequently sterilized using gamma irradiation. Since we planned to use these materials in cardiovascular applications, it was decided that their hemocompatibility would also be tested. The results of these tests revealed that changes in the structures of the materials initiated by sterilization may exert thrombogenic and anticoagulant impacts. Moreover, the microscopic analysis suggested that the solvent system used in the preparation of the materials potentially affects the behavior of erythrocytes; however, no indication of the occurrence of hemolysis was detected.

Infection of the aorta is rare but potentially very dangerous. Under normal circumstances the aorta is very resistant to infections. Following some afflictions, the infection can pass to the aorta from blood or the surrounding tissues. The authors present their 5-year experience with therapy of various types of infections of the abdominal aorta. In the 5-year period between January 2008 and December 2012, the Surgical Clinic of the University Hospital in Pilsen treated 17 patients with acute infection of the abdominal aorta. They included 9 males and 8 females. The mean age was 73.05 years (58-90). The most common pathogens were Salmonella (7), Staphylococcus aureus (2), Klebsiella pneumoniae (1), Listeria monocytogenes (1), and Candida albicans (1). Two cases included mixed bacteria and no infectious agent was cultured in three cases. In 14 cases (82.6%) we decided on an open surgical solution, i.e., resection of the affected abdominal aorta, extensive debridement, and vascular reconstruction. In all of these 14 cases we decided on in situ reconstruction. Twelve cases were treated using silver-impregnated prostheses. An antibiotic impregnated graft was used in one case and fresh aortic allograft in one case. In one case (5.9%) we decided on an endovascular solution, i.e., insertion of a bifurcation stent graft and prolonged antibiotic therapy. In two cases (11.8%) we decided on conservative treatment, as both patients refused any surgical therapy. Morbidity was 47.2% (8 patients). In one case we had to perform reoperation of a patient on the 15th postoperative day to evacuate the postoperative hematoma. The 30-day mortality was 5.9% (1 patient). The hospital mortality was 11.8% (2 patients). One patient died on the 42nd postoperative day due to multiorgan failure following resection of perforated aortitis. During follow-up (average 3.5 years), we had no case of infection or thrombosis of the vascular prosthesis. Patients with mycotic aneurysms or acute aortitides face a high risk of death. One can legitimately expect an increase of "aortic infections" to parallel the increase of immunocompromised individuals. Surgical procedures for infectious aortitis are always demanding and require excellent interdisciplinary cooperation, but, as this experience shows, can lead to midterm survival.

Information about the tissue characteristics of abdominal aortic aneurysms (AAAs), some of which may be reflected in the serum, can help to elucidate AAA pathogenesis and identify new AAA biomarkers. This information would be beneficial not only for diagnostics and follow-up but also for potential therapeutic intervention. Therefore, the aim of our study was to compare the expression of structural proteins, immune factors (T and B lymphocytes, macrophages, neutrophils and pentraxin 3 (PTX3)), osteoprotegerin (OPG), microvessels and hypoxic cells in AAA and nonaneurysmal aortic walls. We examined specimens collected during surgery for AAA repair (n = 39) and from the abdominal aortas of kidney donors without AAA (n = 8). Using histochemical and immunohistochemical methods, we quantified the areas positive for smooth muscle actin, desmin, elastin, collagen, OPG, CD3, CD20, MAC387, myeloperoxidase, PTX3, and hypoxia-inducible factor 1-alpha and the density of CD31-positive microvessels. AAA samples contained significantly less actin, desmin, elastin and OPG, more collagen, macrophages, neutrophils, T lymphocytes, B lymphocytes, hypoxic cells and PTX3, and a greater density of vasa vasorum (VV) than those in non-AAA samples. Hypoxia positively correlated with actin and negatively correlated with collagen. Microvascular density was related to inflammatory cell infiltrates, hypoxia, PTX3 expression and AAA diameter. The lower OPG expression in AAAs supports the notion of its protective role in AAA remodeling. AAA contained altered amounts of structural proteins, implying reduced vascular elasticity. PTX3 was upregulated in AAA and colocalized with inflammatory infiltrates. This evidence supports further evaluation of PTX3 as a candidate marker of AAA. The presence of aortic hypoxia, despite hypervascularization, suggests that hypoxia-induced neoangiogenesis may play a role in AAA pathogenesis. VV angiogenesis of the AAA wall increases its vulnerability.