Dan Simionescu

Biocom

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Agneta Simionescu

Clemson University

Marius Harpa

Universitatea de Medicină, Farmacie, Științe și Tehnologie „George Emil Palade” din Târgu Mureș

Horațiu Suciu

Universitatea de Medicină, Farmacie, Științe și Tehnologie „George Emil Palade” din Târgu Mureș

Jun Liao

The University of Texas at Arlington

Radu Deac

Universitatea de Medicină, Farmacie, Științe și Tehnologie „George Emil Palade” din Târgu Mureș

Ionela Movileanu

Universitatea de Medicină, Farmacie, Științe și Tehnologie „George Emil Palade” din Târgu Mureș

Leslie Neil Sierad

Clemson University

Ovidiu Simion Cotoi

Universitatea de Medicină, Farmacie, Științe și Tehnologie „George Emil Palade” din Târgu Mureș

Narendra Vyavahare

Clemson University

Megan Casco

Clemson University

Cooperative Institutions

Clemson University

Universitatea de Medicină, Farmacie, Științe și Tehnologie „George Emil Palade” din Târgu Mureș

Eindhoven University of Technology

University of California, Irvine

Medizinische Hochschule Hannover

Aarhus University Hospital

Biocom

Romanian Academy

Bakulev Scientific Center for Cardiovascular Surgery Russian Academy of Medical Sciences

Pontifícia Universidade Católica do Paraná

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Mapping of glutaraldehyde‐treated bovine pericardium and tissue selection for bioprosthetic heart valves

Journal of Biomedical Materials Research (1993)

Dan Simionescu Agneta Simionescu Radu Deac

Abstract Glutaraldehyde‐crosslinked bovine pericardium is widely used in bioprosthetic heart valve fabrication. In an attempt to set a scientific basis for more reproducible tissue selection, we produced and analyzed topographical maps of glutaraldehyde‐treated bovine pericardium. Whole pericardia were divided into specific anatomical areas and their thickness was measured and mapped on templates. In each area, the suture holding power was determined in both parallel and perpendicular (to the base‐apex line) directions; analyses of the tearing patterns in each fragment were used to evaluate predominant fiber orientation, and observations were confirmed by polarized light microscopy. Complete maps were superimposed graphically to aid in the selection of certain areas that would have known fiber orientation, high suture holding power, and suitable thickness. Our results describe regional heterogeneity of bovine pericardial structure and mechanical properties, specifically demonstrating variations in thickness, suture holding power, and collagen fiber orientation. Two areas of choice (representing about 35% of the total) were described as suitable for use in bioprosthetic heart valve fabrication. © 1993 John Wiley & Sons, Inc.

Glutaraldehyde

Tearing

10.1002/jbm.820270602

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Citations (53)

Prevention of calcification in bioprosthetic heart valves: challenges and perspectives

Expert Opinion on Biological Therapy (2004)

Dan Simionescu

AbstractSurgical replacement with artificial devices has revolutionised the care of patients with severe valvular diseases. Mechanical valves are very durable, but require long-term anticoagulation. Bioprosthetic heart valves (BHVs), devices manufactured from glutaraldehyde-fixed animal tissues, do not need long-term anticoagulation, but their long-term durability is limited to 15 – 20 years, mainly because of mechanical failure and tissue calcification. Although mechanisms of BHV calcification are not fully understood, major determinants are glutaraldehyde fixation, presence of devitalised cells and alteration of specific extracellular matrix components. Treatments targeted at the prevention of calcification include those that target neutralisation of the effects of glutaraldehyde, removal of cells, and modifications of matrix components. Several existing calcification-prevention treatments are in clinical use at present, and there are excellent mid-term clinical follow-up reports available. The purpose of this review is to appraise basic knowledge acquired in the field of prevention of BHV calcification, and to provide directions for future research and development.bioprosthetic heart valvecalcificationcollagenelastinglutaraldehydemineralisation

Glutaraldehyde

10.1517/14712598.4.12.1971

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Citations (108)

Structural requirements for stabilization of vascular elastin by polyphenolic tannins

Biomaterials (2006)

Jason C. Isenburg N KARAMCHANDANI Dan Simionescu Naren Vyavahare

Tannic acid

10.1016/j.biomaterials.2006.02.016

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Citations (106)

Interobserver variability in physician-modified endograft planning by comparison with a three-dimensional printed aortic model

Journal of Vascular Surgery (2015)

Issam Koleilat Michael Jaeggli Joseph A. Ewing Mark P. Androes Dan Simionescu

Inferior mesenteric artery

Computed Tomography Angiography

10.1016/j.jvs.2015.09.044

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Citations (32)

Longitudinal Stretching for Maturation of Vascular Tissues Using Magnetic Forces

Bioengineering (2016)

Timothy R. Olsen Megan Casco Austin Herbst Grace Evans Taylor Rothermel

Cellular spheroids were studied to determine their use as "bioinks" in the biofabrication of tissue engineered constructs. Specifically, magnetic forces were used to mediate the cyclic longitudinal stretching of tissues composed of Janus magnetic cellular spheroids (JMCSs), as part of a post-processing method for enhancing the deposition and mechanical properties of an extracellular matrix (ECM). The purpose was to accelerate the conventional tissue maturation process via novel post-processing techniques that accelerate the functional, structural, and mechanical mimicking of native tissues. The results of a forty-day study of JMCSs indicated an expression of collagen I, collagen IV, elastin, and fibronectin, which are important vascular ECM proteins. Most notably, the subsequent exposure of fused tissue sheets composed of JMCSs to magnetic forces did not hinder the production of these key proteins. Quantitative results demonstrate that cyclic longitudinal stretching of the tissue sheets mediated by these magnetic forces increased the Young's modulus and induced collagen fiber alignment over a seven day period, when compared to statically conditioned controls. Specifically, the elastin and collagen content of these dynamically-conditioned sheets were 35- and three-fold greater, respectively, at seven days compared to the statically-conditioned controls at three days. These findings indicate the potential of using magnetic forces in tissue maturation, specifically through the cyclic longitudinal stretching of tissues.

Vascular tissue

Matrix (chemical analysis)

10.3390/bioengineering3040029

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Citations (10)

Immunomodulatory effects of adipose tissue-derived stem cells on elastin scaffold remodeling in diabetes

Tissue Engineering and Regenerative Medicine (2016)

James Chow Dan Simionescu Anna L. Carter Agneta Simionescu

10.1007/s13770-016-0018-x

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Decellularization in Heart Valve Tissue Engineering

Springer eBooks (2018)

Katherine M. Copeland Bo Wang Xiaodan Shi Dan Simionescu Yi Hong

Decellularization

10.1007/978-3-030-01993-8_12

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Diabetes-induced early molecular and functional changes in aortic heart valves in a murine model of atherosclerosis

Diabetes and Vascular Disease Research (2019)

Monica Mădălina Tucureanu Alexandru Filippi Nicoleta Alexandru Cristina Ana Constantinescu Letiția Ciortan

Diabetes contributes directly to the development of cardiovascular aortic valve disease. There is currently no drug therapy available for a dysfunctional valve and this urges the need for additional research to identify distinctive mechanisms of cardiovascular aortic valve disease evolution. The aim of this study was to evaluate changes of valvular aortic lesions induced in a hyperlipemic ApoE −/− mouse model by early type 1 diabetes onset (at 4 and 7 days after streptozotocin induction). The haemodynamic valve parameters were evaluated by echography and blood samples and aortic valves were collected. Plasma parameters were measured, and inflammatory, remodelling and osteogenic markers were evaluated in the aortic valves. Next, correlations between all parameters were determined. The results showed early aortic valve dysfunction detected by echography after 1 week of diabetes; lesions were found in the aortic root. Moreover, increased expression of cell adhesion molecules, extracellular matrix remodelling and osteogenic markers were detected in hyperlipemic ApoE −/− diabetic mice. Significant correlations were found between tissue valve biomarkers and plasmatic and haemodynamic parameters. Our study may help to understand the mechanisms of aortic valve disease in the diabetic milieu in order to discover and validate new biomarkers of cardiovascular aortic valve disease in diabetes and reveal new possible targets for nanobiotherapies.

10.1177/1479164119874469

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Citations (19)

Macrophage differentiation and polarization on a decellularized pericardial biomaterial

Biomaterials (2010)

Marianne B. Ariganello Dan Simionescu Rosalind S. Labow J. Michael Lee

Decellularization

Biomaterial

Macrophage polarization

M2 Macrophage

Osteopontin

10.1016/j.biomaterials.2010.09.004