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1

Elastin and collagen fibres alterations for abdominal aortic aneurysms population with constant maximum diameter size

Kobielarz M., Maksymowicz K., Będziński R.

Engineering of Biomaterials

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2011

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Vol. 14, no. 102

2--6

EN

Development of abdominal aortic aneurysm (AAA) is a dynamic process proceeding as a result of the multi-factor pathological remodelling of elastin and collagen fibres, results an aneurysm expansion. In clinical practice, development of AAA is identified with aneurysm growth. Hence, the aim of this paper is to propose a taxonomy of load-bearing structural components alterations for AAA with relatively constant maximum diameter (average diameter 6.9±0.8 cm). Structural investigations of normal (n=47) and aneurismal (n=46) vessels were carried out on the basis of histological and ultrastructural examinations. The histological preparations were subjected to histometric evaluation; the number of collagen and elastin fibres and additionally the thickness of the particular vascular wall layers. A qualitative analysis of the abdominal aortic wall, mainly estimation of fibres arrangement, based on histological and ultrastructural (SEM) examinations were additionally performed. Using a cluster analysis, three stages of load-bearing fibres alterations for AAA population were distinguished. The clusters were systematized according to NAA results. For AAA population with relatively constant maximum diameter in the first stage of load-bearing fibres remodeling was observed a substantial loss of elastin fibres. The second stage is characterized by an increase in the number of collagen fibres. In the final stage the number of collagen is dramatically reduced. Presented results provide evidence to risk of AAA rupture is not connected with AAA size but a remodelling of extra-cellular matrix proteins. The remodelling is accompanied by changes in the AAA wall thickness, which should be taken into consideration when evaluating the degree of advancement of this disease.

2

Ocena histologiczna i ultrastrukturalna ścian tętniaków aorty brzusznej

Kobielarz M., Maksymowicz K., Kaleta K., Kuropka P., Marycz K., Będziński R.

Engineering of Biomaterials

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2010

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Vol. 13, no. 99-101

83--87

PL

Rozwój tętniaków, w tym aorty brzusznej (AAA) jest dynamicznym procesem, który zachodzi w wyniku wieloczynnikowego, patologicznego remodelingu tkanki łącznej ściany aorty. Badania strukturalne ścian naczyń tętniczych (zdrowych i z tętniakiem) przeprowadzono w oparciu o analizę histologiczną i ultrastrukturalną. Analiza porównawcza wyników wykazała, że w przypadku preparatów ścian tętniaków aorty brzusznej odnotowano cały szereg zmian, które są charakterystyczne dla rozważanego schorzenia, w tym: wzmożony proces neowaskularyzacji oraz obecność nacieku zapalnego. Ponadto, odnotowano zatarcie granic między warstwami oraz redukcję ich grubości, co szczególnie zaznaczyło się w przypadku błony wewnętrznej. Zaobserwowano istotny ubytek włókien elastynowych oraz zmienny co do intensywności w poszczególnych przypadkach ubytek włókien kolagenowych. Wykazano także, że zmiany w liczbie włókien tkanki łącznej odgrywają kluczową rolę w procesie rozwoju AAA.

EN

The development of abdominal aortic aneurysm (AAA) is a dynamic process proceeding as a result of the multi-factor pathological remodelling of the connective tissue. Structural investigations of normal and aneurismal vessels were carried out on the basis of histological and ultrastructural examinations. A comparative analysis of the experimental results revealed a whole series of changes characteristic of the AAA walls (intensified neovascularisation and inflammatory infiltrations). In addition, the boundaries between the layers were found to be blurred and the thickness of the layers was reduced. A substantial loss of elastin fibres and a case-specific loss of collagen fibres were observed. The number of connective tissue fibres play a key role in the AAA development.

3

CFD simulations of blood flow through abdominal part of aorta

Polanczyk A., Piechota A.

Challenges of Modern Technology

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2010

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Vol. 1, no. 1

34--39

EN

The aim of this research was to show superiority of using real geometries in simulations of blood fl ow through cardiovascular system. Our model compared blood fl ow through an abdominal part of aorta reconstructed with a use of data from an AngioTK research with the 3DDoctor software to geometries with the same diameters at inlet and outlet as mention before but created only with the Gambit 2.2.30 software without data from AngioTK. Blood fl ow simulations were prepared with the Fluent 6.2.16 software. Calculations of fl ow through a real geometry allows to obtain realistic results of values connected with process of blood fl ow. Results showed that calculations blood fl ow through a virtual geometry lasted two times longer than for a real geometry. Mesh for a real geometry consist about 600.000 elements and for a virtual geometry about 900.000 elements. Wall shear stress and blood velocity was higher for a real geometry and closer to that in human organism. It was shown that calculating a virtual geometry vessel was to big simplifi cation when investigating blood fl ow through a vessel. Application of mathematical models based on real geometries gives more realistic results than artifi cial geometries. Virtual models have lots of simplifi cations which results are far away from expectations. Simplifi cations depend on the model that is used.

4

Analiza porównawcza składu pierwiastkowego ścian aorty brzusznej i tętniaka aorty brzusznej

Kobielarz M., Marycz K., Szotek S., Będziński R.

Engineering of Biomaterials

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2009

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Vol. 12, no. 89-91

185--187

PL

Głównym celem pracy było określenie procentowego składu pierwiastkowego ścian zdrowej aorty brzusznej (NAA) i tętniaka aorty brzusznej (AAA) na podstawie mikroanalizy rentgenowskiej (Rtg) dla dużej populacji materiału badawczego, ażeby sprawdzić użyteczność metody do różnicowania (na poziomie molekularnym) materiału biologicznego pod kątem zmian chorobowych. Dla żadnego z analizowanych pierwiastków nie odnotowano, na poziomie istotności p=0,05, istotnych statystycznie zmian w procentowym rozkładzie pierwiastków między preparatami ścian zdrowych aort brzusznych oraz tętniaków. Na podstawie uzyskanych wyników wykazano, biorąc pod uwagę wielkość grup badawczych, że zastosowana metoda nie umożliwia różnicowania materiału biologicznego na założonym poziomie istotności.

EN

The main aim of paper was evaluation of chemical elements composition of normal abdominal aortic walls (NAA) and abdominal aortic aneurysms walls (AAA) based on X-ray microanalysis for a numerous and diversified population in order to differentiate (on molecular level) biological materials according pathological changes. For neither of analyzed elements were noticed statistically significant on the confidence level p=0,05 differences between NAA walls and AAA walls. On the basis of the obtained results it can be concluded that used methods isn’t sufficient to differentiation of biological materials according pathological changes.