Most cited article - PubMed ID 34907746
Three-layer collagen-based vascular graft designed for low-flow peripheral vascular reconstructions
INTRODUCTION: This study examines the mechanical properties of thoracic aortic false aneurysms (TAFA) and how the use of vascular prostheses, native vessels, and anastomoses affects their development. This is done through tensile testing, simulating a Bentall procedure, which is the most common surgery leading to TAFA development. METHODS: We conducted uniaxial tensile tests on the native right and left coronary arteries from five cadaveric donors. They were anastomosed to two vascular prostheses in the longitudinal and circumferential directions to assess their mechanical responses under load. RESULTS AND DISCUSSION: All anastomosis specimens ruptured on the native vessel side, with no breaches occurring on the prosthesis side. The P2 prosthesis exhibited a mechanical response closer to that of the native vessel compared to the P1 prosthesis. There were no statistically significant differences in wall thickness or mechanical properties between the left and right coronary artery samples, leading to the merging of these groups. The strain of the anastomosis in the longitudinal direction was significantly higher than in the circumferential direction. In both directions, the strain at the onset of rupture was greater than that of the native vessel, with a particularly notable difference in the longitudinal direction. Although there was no significant difference in stress values between the longitudinal and circumferential directions, forces per suture were slightly higher in the circumferential direction. CONCLUSION: Using the "endo-button buttress technique" with a double-layer anastomosis can help distribute the load and reduce stress. An alternative option is to use a Carrel patch to reinforce the connection between the target site and the conduit. Additionally, autologous pericardium can be employed for reinforcement.
- Keywords
- Aortic pseudoaneurysm, Bentall procedure, Coronary arteries, Tensile testing, Thoracic aortic false aneurysm,
- MeSH
- Anastomosis, Surgical MeSH
- Aortic Aneurysm, Thoracic * surgery physiopathology MeSH
- Aorta, Thoracic * surgery physiopathology MeSH
- Blood Vessel Prosthesis * MeSH
- Coronary Vessels surgery physiopathology MeSH
- Middle Aged MeSH
- Humans MeSH
- Stress, Mechanical MeSH
- Cadaver MeSH
- Aneurysm, False * surgery physiopathology MeSH
- Tensile Strength MeSH
- Aged MeSH
- Check Tag
- Middle Aged MeSH
- Humans MeSH
- Male MeSH
- Aged MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
Cardiovascular diseases are the most important cause of morbidity and mortality in the civilized world. Stenosis or occlusion of blood vessels leads not only to events that are directly life-threatening, such as myocardial infarction or stroke, but also to a significant reduction in quality of life, for example in lower limb ischemia as a consequence of metabolic diseases. The first synthetic polymeric vascular replacements were used clinically in the early 1950s. However, they proved to be suitable only for larger-diameter vessels, where the blood flow prevents the attachment of platelets, pro-inflammatory cells and smooth muscle cells on their inner surface, whereas in smaller-diameter grafts (6 mm or less), these phenomena lead to stenosis and failure of the graft. Moreover, these polymeric vascular replacements, like biological grafts (decellularized or devitalized), are cell-free, i.e. there are no reconstructed physiological layers of the blood vessel wall, i.e. an inner layer of endothelial cells to prevent thrombosis, a middle layer of smooth muscle cells to perform the contractile function, and an outer layer to provide innervation and vascularization of the vessel wall. Vascular substitutes with these cellular components can be constructed by tissue engineering methods. However, it has to be admitted that even about 70 years after the first polymeric vascular prostheses were implanted into human patients, there are still no functional small-diameter vascular grafts on the market. The damage to small-diameter blood vessels has to be addressed by endovascular approaches or by autologous vascular substitutes, which leads to some skepticism about the potential of tissue engineering. However, new possibilities of this approach lie in the use of modern technologies such as 3D bioprinting and/or electrospinning in combination with stem cells and pre-vascularization of tissue-engineered vascular grafts. In this endeavor, sex-related differences in the removal of degradable biomaterials by the cells and in the behavior of stem cells and pre-differentiated vascular cells need to be taken into account. Key words: Blood vessel prosthesis, Regenerative medicine, Stem cells, Footprint-free iPSCs, sr-RNA, Dynamic bioreactor, Sex-related differences.
AIM: To assess the systemic and local immunological response to subcutaneous implants of a vascular graft covered with collagen extracted from the European carp (freshwater fish) or with collagen of bovine origin. METHODS: Pieces of a vascular graft covered by pure bovine (Bos taurus, BOV, n=14) or carp (Cyprinus carpio, CYP, n=14) collagen 5 mm in size were implanted subcutaneously in the dorsum of a Balb/cOla mice. A sham operation group of 12 animals served as the control. At 7 and 14 days after the operation, one-half of each group was terminated and blood for serum, spleen, and implant with surrounding tissue were collected. Mean cytokine (TNF-α, IL-10, IL-4, IL-1β, IL-13, and IFN-γ) levels in serum were determined using ELISA. Spleen cell cultures were used for in vitro testing of lymphocyte proliferation and cytokine secretion. Local expressions of IL-6, IL-10, TNF-α, TGF-β, CCL-2, and CCL-3 were determined using PCR. RESULTS: We found no significant difference among control, BOV, and CYP groups in mean cytokine serum levels at seven days. At day 14, the BOV group had higher levels of TNF-α (P=.018) and both the BOV and CYP groups had lower levels of IL-4 (P=.011 and P=.047, respectively) compared with the control group. Both tested implants showed only a minimal effect on the production of selected cytokines. Cell proliferation in the CYP group stimulated by CYP gel at 14 days was significantly lower than by BOV gel in BOV group (P=.0031) or by CYP gel in the control group (P=.041). The difference between the groups in the local RNA expression of all the tested mediators both at 7 and at 14 days was not significant apart from a lower level of TNF-α in the BOV group compared to CYP at 14 days (P=.013). CONCLUSIONS: Implants covered with carp collagen induce an immunological response that is comparable to that of bovine collagen covered implants in a mouse model.
- MeSH
- Cellular Microenvironment MeSH
- Blood Vessel Prosthesis * MeSH
- Cytokines blood MeSH
- Carps MeSH
- Collagen immunology MeSH
- RNA, Messenger genetics metabolism MeSH
- Mice, Inbred BALB C MeSH
- Cell Proliferation MeSH
- Cattle MeSH
- Spleen cytology MeSH
- Animals MeSH
- Check Tag
- Cattle MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Names of Substances
- Cytokines MeSH
- Collagen MeSH
- RNA, Messenger MeSH