Arterial wall elastic fibers, made of 90% elastin, are arranged into elastic lamellae which are responsible for the resilience and elastic properties of the large arteries (aorta and its proximal branches). Elastin is synthesized only in early life and adolescence mainly by the vascular smooth muscles cells (VSMC) through the cross-linking of its soluble precursor, tropoelastin. In normal aging, the elastic fibers become fragmented and the mechanical load is transferred to collagen fibers, which are 100-1000 times stiffer than elastic fibers. Minoxidil, an ATP-dependent K+ channel opener, has been shown to stimulate elastin expression in vitro, and in vivo in the aorta of male aged mice and young adult hypertensive rats. Here, we have studied the effect of a 3-month chronic oral treatment with minoxidil (120 mg/L in drinking water) on the abdominal aorta structure and function in adult (6-month-old) and aged (24-month-old) male and female mice. Our results show that minoxidil treatment preserves elastic lamellae integrity at both ages, which is accompanied by the formation of newly synthesized elastic fibers in aged mice. This leads to a generally decreased pulse pressure and a significant improvement of the arterial biomechanical properties in female mice, which present an increased distensibility and a decreased rigidity of the aorta. Our studies show that minoxidil treatment reversed some of the major adverse effects of arterial aging in mice and could be an interesting anti-arterial aging agent, also potentially usable for female-targeted therapies.

Decellularized porcine heart valves offer promising potential as biocompatible prostheses. However, this procedure alter matrix fibres and glycans, leading to lower biomechanical resistance and increased their thrombotic potential. Therefore, their durability is limited due to calcification and weak regeneration in vivo. Surface modifications are highly requested to improve the scaffolds re-endothelialization required to restore functional and haemocompatible heart valve. Fucoidan, a natural sulphated polysaccharide, carries antithrombotic and anti-inflammatory properties and is known to enhance endothelial adhesion and proliferation when associated with vascular endothelial growth factor (VEGF). Based on these features, we constructed fucoidan/VEGF polyelectrolyte multilayer film (PEM) coated valve scaffold in an attempt to develop functional heart valve bioprosthesis. We investigated the haemocompatibility of the PEM coated valve scaffolds, the adhesion and growth potential of endothelial cells (HUVECs) in flow, as well as long term culture with stem cells. Fucoidan/VEGF PEM coated scaffolds demonstrated antithrombotic and non-calcifying properties. The PEM application increased HUVECs adhesion in flow (6 h) and HUVECs viability over time (72 h). HUVECs were well spread and aligned in flow direction. Interestingly, stem cells infiltration was improved by the PEM coating at 21 days. Thus, the fucoidan/VEGF PEM is a promising surface modification to obtain valve bioprostheses for clinical applications with increased antithrombotic and re-endothelialization potential.

The aim of this study was to determine the plasma levels of Matrix metalloproteinases (MMPs): MMP-2, MMP-3, MMP-9, and their inhibitors (TIMPs): TIMP-1, and TIMP-2 in hypertensive patients and healthy subjects The study has involved 60 hypertensive patients and 61 adult healthy controls. Activity of pro-MMP-9 and pro-MMP-2, was carried by gelatin zymography method and MMP-3, TIMP-1, and TIMP-2 levels were determined by ELISA methods. The mean plasma activity of pro-MMP-9 in the hypertensive group and the control group were significantly different (153.33 ± 129.33 vs 90.38 ± 97.49x103 densitometric units/μl; p < 0.01). The plasma concentration of MMP-3 was significantly higher in hypertensive subjects then healthy subjects (20.24 ± 8.63 vs 16.41 ± 6.8ng/ml; p < 0.05). Whereas the plasma concentration of TIMP-1 in the hypertensive group was lower than that in the control group 88.96 ± 26.9 vs 93.96 ± 27.28ng/ml. The MMP-3/TIMP-1 and the MMP-3/TMP-2 ratios were higher in hypertensive subjects than healthy subjects. We found significant positive correlation between systolic blood pressure and pro-MMP-9 (r = 0.311, p < 0.001). The present study identified abnormalities in plasma markers for extracellular matrix metabolism in hypertensive patients.

Objective: Hypertension is an important cause of cardiovascular disease. In hypertensive patients the vascular remodeling is associated with changes in plasma levels of matrix metalloproteinases (MMPs), and tissue inhibitor of metalloproteinases (TIMPs). The aim of this study was to determine the plasma levels of MMP-2, MMP-3, MMP-9, and their TIMPs: TIMP-1 and TIMP-2 in hypertensive patients and healthy subjects. Design and method: The study has involved 40 hypertensive patients and 41 adult healthy controls. Pro-MMP-3 and active form MMP-3, TIMP-1, and TIMP-2 levels were determined in citrate plasma by ELISA methods using commercial reagents (R&D Systems, Lille France). To detect pro-MMP-9 and pro-MMP-2 as well as their conversion into active MMP-9 and MMP-2, was carried by gelatin zymography method. Results: The mean plasma activity of pro-MMP-9 in the hypertensive group and the control group were significantly different (153.33 ± 129.33 vs 90.38 ± 97.49 × 103 densitometric units/μl; p < 0.01). The plasma concentration of MMP-3 was significantly higher in hypertensive subjects then healthy subjects (20.24 ± 8.63 vs 16.41 ± 6.8 ng/ml; p < 0.05). The plasma concentration of TIMP-1 in the hypertensive group was lower than that in the control group 88.96 ± 26.9 vs 93.96 ± 27.28 ng/ml. Conclusions: These differential plasma matrix metalloproteinase and tissue inhibitors of metalloproteinase profile suggest a more aggressive proteolytic milieu exists in hypertensive patients which in turn would promote a more rapidly progressive vascular remodeling. While additional studies are necessary, these distinct differences in determinants of vascular matrix structure, and may be potentially useful as biomarkers for diagnosis and prognosis in hypertension.

Objective: Hypertension is an important cause of cardiovascular disease. In hypertensive patients the vascular remodeling is associated with changes in plasma levels of matrix metalloproteinases (MMPs), and tissue inhibitor of metalloproteinases (TIMPs). The aim of this study was to determine the plasma levels of MMP-2, MMP-3, MMP-9, and their TIMPs: TIMP-1 and TIMP-2 in hypertensive patients and healthy subjects. Design and method: The study has involved 40 hypertensive patients and 41 adult healthy controls. Pro-MMP-3 and active form MMP-3, TIMP-1, and TIMP-2 levels were determined in citrate plasma by ELISA methods using commercial reagents (R&D Systems, Lille France). To detect pro-MMP-9 and pro-MMP-2 as well as their conversion into active MMP-9 and MMP-2, was carried by gelatin zymography method. Results: The mean plasma activity of pro-MMP-9 in the hypertensive group and the control group were significantly different (153.33 ± 129.33 vs 90.38 ± 97.49 × 103 densitometric units/μl; p < 0.01). The plasma concentration of MMP-3 was significantly higher in hypertensive subjects then healthy subjects (20.24 ± 8.63 vs 16.41 ± 6.8 ng/ml; p < 0.05). The plasma concentration of TIMP-1 in the hypertensive group was lower than that in the control group 88.96 ± 26.9 vs 93.96 ± 27.28 ng/ml. Conclusions: These differential plasma matrix metalloproteinase and tissue inhibitors of metalloproteinase profile suggest a more aggressive proteolytic milieu exists in hypertensive patients which in turn would promote a more rapidly progressive vascular remodeling. While additional studies are necessary, these distinct differences in determinants of vascular matrix structure, and may be potentially useful as biomarkers for diagnosis and prognosis in hypertension.

The main components of elastic fibers, elastin and fibrillin-containing microfibrils play a structural and mechanical role in the arteries and their essential function is to provide elasticity and resilience to the tissues. However, through control of the quiescent contractile phenotype of arterial smooth muscle cells, elastin also acts as an autocrine factor and, via the binding of 'latent transforming growth factor (TGF)-beta binding protein (LTBP) - latency-associated peptide (LAP) - TGF-beta' complexes, fibrillins regulate the activation and availability of TGF-beta s. These recent discoveries are detailed in this review. (C) 2014 Elsevier Masson SAS. All rights reserved.

Aims: Age-related arterial alterations affecting cells, matrix and biomolecules are the main culprit for initiation and progression of cardiovascular disease (CVD). Despite decreasing trends since around 1970 in industrialized countries, CVD is the leading cause of death in developing countries. The objective of this study is to gain further insights into the complex mechanism of elastic tissue ageing in human aortic blood vessels.

Le vieillissement des vaisseaux sanguins recouvre un ensemble d’événements touchant aussi bien les cellules que la matrice extracellulaire de la paroi vasculaire. Le vieillissement normal est associé à des processus dégénératifs multiples, tels que : rigidification artérielle liée à la fragmentation des fibres élastiques et l’accumulation de collagènes pariétaux, pontage progressif des fibres de collagène et dérégulation de la vasomotricité liée à un dysfonctionnement des cellules musculaires lisses ou endothéliales. Le vieillissement pathologique, c’est-à-dire n’affectant qu’une partie de la population, peut avoir des conséquences sur tout l’organisme, comme dans l’hypertension, ou avoir des effets plus localisés, comme dans le cas des anévrismes, de l’athérosclérose ou des varices. Certains travaux suggèrent que le mode de vieillissement vasculaire pourrait aussi être lié à l’état initial du système vasculaire. En particulier, il a été montré que des modifications structurales et fonctionnelles de la paroi artérielle liées au déficit en élastine sont capables de modifier à long terme les processus normaux du vieillissement. L’expression précoce de l’élastine apparaît ainsi comme un régulateur du vieillissement artériel. La fonction cardiovasculaire de l’adulte et son évolution au cours du vieillissement, ainsi que la susceptibilité à développer des pathologies cardiovasculaires, dépendent donc étroitement des conditions initiales et notamment du bon déroulement de l’élastogenèse. Ces aspects seront sans doute à prendre en compte dans les futures stratégies thérapeutiques.

La quantité et/ou la qualité des fibres élastiques artérielles sont modifiées dans plusieurs situations pathologiques (anévrisme, athérosclérose,…) et au cours du vieillissement. C'est la raison pour laquelle nous étudions les gènes qui régulent la composition de la matrice extracellulaire artérielle et plus particulièrement les gènes régulateurs de la synthèse de l'élastine. Comparé à plusieurs autres souches de rat, le rat Brown Norway (BN) a une quantité réduite d'élastine dans son aorte ; ceci est liée à une synthèse déficiente de tropoélastine chez le rat en croissance (Sauvage et al, 1997 et 1999 ; Behmoaras et al, 2004). En utilisant des rats F2 BN × LOU, la mesure de la quantité d'élastine dans leur aorte thoracique et l'analyse de 200 marqueurs polymorphiques sur leur ADN, trois "Quantitative Trait Loci (QTL)" contrôlant la quantité d'élastine artérielle ont été mis en évidence : deux sur le chromosome 2 et un sur le chromosome 14 (Gauguier et al, 2005). Parallèlement, l'utilisation de puces a permis l'analyse des ARNm différentiellement exprimés dans l'aorte des rats BN et des rats LOU de 6 semaines. Ces deux méthodes complémentaires nous ont permis de mettre en évidence les gènes potentiellement régulateurs de la synthèse de l'élastine. Plusieurs gènes candidats régulent les concentrations de potassium intracellulaire. Nous avons donc testé in vitro et in vivo des agents anti-hypertenseurs ouvreurs de canaux potassiques ATP-dépendants tel le minoxidil (Mx) : des CML d'aorte de rat BN ont été traitées avec le minoxidil sulfate avant de mesurer la quantité d'ARNmE, la transcription du gène élastine et la stabilité des ARNmE ; des rats BN de 3 semaines ont été traités pendant 10 semaines avec le Mx (22 mg/kg/j) avant d'analyser la quantité d'élastine dans l'aorte. Nous avons ainsi démontré que le Mx stimule la synthèse de l'élastine via l'augmentation simultanée de la transcription du gène et de la stabilité des ARNm. Le traitement des rats BN avec Mx induit une augmentation de la quantité d'élastine artérielle. Le minoxidil peut donc être potentiellement utilisée chez les patients déficients en élastine artérielle.

Williams-Beuren syndrome (WBS) (OMIM# 194050) is a rare, most often sporadic, genetic disease caused by a chromosomal microdeletion at locus 7q11.23 involving 28 genes. Among these, the elastin gene codes for the essential component of the arterial extracellular matrix. Developmental disorders usually associate an atypical face, cardiovascular malformations (most often supravalvular aortic stenosis and/or pulmonary artery stenosis) and a unique neuropsychological profile. This profile is defined by moderate mental retardation, relatively well-preserved language skills, visuospatial deficits and hypersociability. Other less known or rarer features, such as neonatal hypercalcemia, nutrition problems in infancy, ophthalmological anomalies, hypothyroidism, growth retardation, joint disturbances, dental anomalies and hypertension arising in adolescence or adulthood, should be treated. The aim of this paper is to summarize the major points of WBS regarding: (i) the different genes involved in the deletion and their function, especially the elastin gene and recent reports of rare forms of partial WBS or of an opposite syndrome stemming from a microduplication of the 7q11.23 locus, (ii) the clinical features in children and adults with a focus on cardiovascular injury, and (iii) the specific neuropsychological profile of people with WBS through its characteristics, the brain structures involved, and learning.

Introduction. - Our goal is to study the effects of tennis practice in pre-pubescent boys on bone remodeling, by means of enzyme activity involved in balance of matrix remodeling (MMP2 and MMP9).Results. - Mineral bone density has been found higher in the dominant arm (P < 0.0001) as well as MMP2 and MMP9 levels in plasma (P < 0.05).Conclusion. - Tennis practice in children increases bone remodeling, which can be assessed by MMP dosage, in addition of densitometry technique. (c) 2007 Elsevier Masson SAS. All rights reserved.

Adaptation to pregnancy involves major maternal anatomical, physiological and metabolic modifications to support the mother's metabolic needs and those of the growing foetus. Invasion of embryonic territories and implantation in humans and other mammals is the result of an active biochemical process. The invasive faculty of cytotrophoblastic cells depends on their capacity to secrete proteolytic enzymes such as matrix metalloproteinases (MMPs). Many studies have addressed the variations in MMPs in placental tissues, but few have reported on their measurements in plasma. Furthermore, the Pregnancy-Associated Glycoproteins (PAGs), which are synthesized in the syncytiotrophoblast and used as early markers of pregnancy in domestic and wild animals, have not yet been studied in rabbits. In this study, we attempt to purify PAGs from rabbit placenta using a previously described methodology and to measure their concentrations as well as those of MMP-2 and MMP-9 in the plasma throughout pregnancy. In the course of the work, we noted certain modifications of the biochemical parameters in plasma during gestation, essentially in glycemia and lipemia. We detected proteins immunologically-related to PAGs in placental extracts between D-14 to D-21. Until now, it has been impossible to develop a homologous RIA in order to measure PAGs in rabbit plasma, as the recovery of PAGs during the purification procedure was very low and PAGs were undetectable in rabbit plasma using heterologous RIAs. Finally, we demonstrated a rise in MMP-2 and -9 at the middle and the end of the gestation. However, the small variations presented by these matrix metalloproteinases preclude the use of plasma levels of these enzymes as early markers of pregnancy progress in the rabbit.

Objective— Ferumoxtran-10 is an MRI contrast agent, which accumulates in macrophages and induces magnetic susceptibility artifacts (MSAs). We evaluated the ability of ferumoxtran-10–enhanced MRI to quantify focal macrophage infiltration in the aortic wall of hypercholesterolemic rabbits. Methods and Results— Six weeks after a double-balloon injury of the infrarenal aorta, 12 hypercholesterolemic rabbits underwent MRI of the aorta before (first MRI) and after (second MRI) intravenous injection of ferumoxtran-10 (n=10) or saline (n=2). A third MRI was performed 5 days later to detect ferumoxtran-10–induced MSA in the aortic wall. Aortas were subsequently processed for histology, immunohistochemistry, and gelatin zymography studies. Injured aortas displayed a macrophage-rich neointima with high-matrix metalloproteinase 2 and 9 activities. Iron stain of injured aortas showed massive accumulation of ferumoxtran-10 in neointimal macrophages. Five days after the injection of ferumoxtran-10, MSAs were detected only in the injured aortas by in vivo MRI and were quantified indirectly using the percentage reduction of luminal area attributable to the extension of these MSAs in the aortic lumen. This parameter correlated with macrophage infiltration on corresponding aortic cross-sections ( r =0.82; P <0.05). Conclusion— Ferumoxtran-10–enhanced MRI allows quantitative assessment of macrophage infiltration induced by balloon angioplasty in the aorta of hypercholesterolemic rabbits.

The extracellular matrix provides a structural framework essential for the functional properties of tissues. In each tissue, the three-dimensional organisation of the extracellular matrix molecules--elastin, collagens, proteoglycans and structural glycoproteins--synthesized during development and growth is optimal for these functions. In adult tissues, proteases are constitutively expressed but have a very low activity and the turn-over of elastic and collagen fibers is very low. During ageing, the interaction of environmental factors (glucose, lipids, calcium...) and modifications of the biosynthesis and degradation processes lead to modifications of extracellular matrix homeostasis and consequently to alterations of tissue functionality. These alterations are increased during pathological processes such as cardiovascular diseases.

Left ventricular (LV) remodeling following myocardial infarction (MI) is a complex process involving extracellular matrix degradation and fibrosis. While early remodeling is beneficial, chronic remodeling leads to decompensated heart failure (HF). We assessed the hypothesis that activation of the plasminogen–MMP system is involved in the remodeling of the infarct scar and compared it to the remaining viable myocardium. MI was induced by coronary artery ligature in 42 male Wistar rats. Three months following surgery, animals were divided into compensated (n = 26) or decompensated (n = 16) groups and compared to sham-operated rats (n = 17). Scar and remaining viable LV myocardium (LVM) were separately analyzed for MMP-2, -7, -9, urokinase type and tissue type plasminogen activator (uPA and tPA) mRNA levels by RT-PCR. Their protein or activity levels, plus those of plasminogen/plasmin, tissue inhibitor of metalloproteinase-1, -2, -4 (TIMP-1, -2, -4) and plasminogen activator inhibitor-1 (PAI-1) were analyzed in tissue conditioned media by Western blot, ELISA and/or zymography. MMP and plasmin proteolytic activities were increased in the scar as compared to paired LVM thus indicating that activation of plasminogen and pro-MMPs is a key event in scar tissue remodeling. MMP and plasminogen activators (uPA, tPA) mRNAs were increased accordingly. Furthermore, inhibitors of the proteolytic enzymes, TIMP-1 and PAI-1 were increased in the scars from failing hearts and LVM thus suggesting a dynamic interplay between proteolysis and its inhibitors. This study shows a high degree of activation of the MMP–plasminogen system and the balance with their inhibitors in the infarcted myocardium, and suggests that this activation participates more to the remodeling of the scar tissue than to the remaining myocardium.