Background: A major problem in the treatment of human hypertension is the late diagnosis of hypertension and, hence, the delayed start of treatment. Very often, hypertension has existed for a long time and cardiac damage has already developed. Therefore, we tested whether late- onset antihypertensive treatment is effective in lowering blood pressure (BP) and in reducing or even preventing left ventricular hypertrophy and fibrosis. Methods: Twenty-one male 60-week-old spontaneously hypertensive rats (SHR) were included. Fourteen rats received oral treatment with captopril (CAP) either as monotherapy or combined with nifedipine (CAP + NIF) over 22 weeks. Seven untreated SHR served as controls. We examined the therapeutic effects on BP, heart weight and histological and biochemical markers of left ventricular remodeling and fibrosis. Results: At 82 weeks of age, BP was reduced in the CAP and CAP + NIF groups by 44 and 51 mmHg, respectively (p < 0.001), but not in untreated controls. Despite the late therapy start, cardiac hypertrophy and fibrosis were attenuated compared to controls. Both treatments reduced heart weight by 1.2 mg/g (25%, p = 0.001) and collagens I and III by 66% and 60%, respectively (p < 0.001), thus proving nearly equivalent cardioprotective efficacy. Conclusion: These data clearly emphasize the benefit of antihypertensive treatment in reducing BP and mitigating the development of cardiac amage even when treatment is started late in life.

No description available.

Migratory cells in vivo move within a predominantly fibrous microenvironment through the action of forces. These dynamic interactions facilitate mechanosensing, critical to fundamental biological processes in pathophysiology. Naturally, the field of mechanobiology has evolved over the past several decades to decipher the role of forces in mechanotransduction using a variety of force-measurement platforms. A central challenge that has yet to be overcome in the field is connecting forces with the interplay between cell shape and ever-changing environment. Here, through design of specific fibrous architectures, a mechanobiological understanding of force feed-forward loop accounting for shape shifting of the environment and cells is developed. Using the non-electrospinning Spinneret Tunable Engineered Parameters (STEP) technique, two complementary force measurement platforms of varying physical attributes are developed to investigate how the force feed-forward loop impacts cell fate. Nanonet Force Microscopy (NFM) comprised of aligned nanonets is designed to study anisotropic cell shapes, while Crosshatch Force Microscopy (CM) comprised of orthogonal arrangement of fibers is designed to study cell bodies of broad shapes. The combination of shapes achieved on these networks recapitulate mesenchymal shapes observed in vivo, which are used to describe cell behaviors not reported before. The new findings include (i) discovery of a new biological structure, termed 3D-perpendicular lateral protrusions (3D-PLPs) which is proposed to be the missing biophysical link in the remodeling of the ECM and perpetuation of desmoplasia. Using NFM, seven discreet steps in formation of force-exerting PLPs anywhere along the cell body is documented, which allow cells to spread laterally and increase in contractility. Using a variety of fiber networks, it is shown that aligned fibers are necessary for PLP formation and suitable environments for myofibroblast activation, and (ii) a force dipole that links matrix deformability with cell contractility. Aided by machine learning, CFM automates the process of fiber feature recognition to measure forces as cells change shapes during migration and differentiate to osteogenic and adipogenic lineages. The force platforms are applied to investigate (i) the bioenergetic contributors fueling cellular migration and a surprisingly overwhelming impact of glycolytic energetic pathway over the traditionally thought mitochondrial energy production is found. However, neither pathway has substantial impact over the cellular force production, and (ii) quantitate the migratory and contractile response of enucleated cytoplasmic fragments naturally shed by cells. A peculiar contractility driven oscillatory migratory phenotype is found, capable of lasting over tens of hours, and absent in intact cells. Overall, new high spatiotemporal capabilities are developed in mechanobiology to quantitate the force-feed forward loops between cell shape and ECM in pathophysiology. / Doctor of Philosophy / Pathophysiology is the study of abnormal changes in the regular body functions of an organism that are causes or consequences of disease onset. Research in this area is mainly focused on identifying the different factors that cause and propagate the disease states such as cancer. Central to many of these processes are events such as cell migration and remodeling of their surrounding environment. The native microenvironment surrounding cells is highly complex and is composed of many classes of macromolecules, with fibrous components being one of the most important. How cells interact with these environments through application of forces and how this further regulates cellular behavior is vital to advancing our understanding of many of these pathophysiological processes. Currently, there is a lack in our understanding of how this dynamic process referred to as the "force feed-forward loop", is perpetuated. This limitation in our understanding can be attributed to the lack of an in vivo mimicking platform that captures this dynamic interaction and is capable of measuring the forces. To this end, the development of two novel single cell force measurement platforms: Nanonet Force Microscopy (NFM) and Crosshatch Force Microscopy (CFM) is presented. These platforms are fiber based systems, generated with the utilization of previously established non-electrospinning technique of Spinneret based Tunable Engineered Parameters (STEP) technique. Using NFM and CFM, forces were computed in wide range of cell shapes from anisotropic to all other spread morphologies. These platforms were applied to identify a new biological structure called perpendicular lateral protrusions and shown to have potential role in the spreading of tumor microenvironment. Furthermore, the force dynamics in physiological processes such as stem cell differentiation into fat cells or bone cells is also identified. How cellular processes such as migration and force production is fueled is also investigated and found to be not heavily reliant on the commonly understood mitochondrial activity. Finally, sub-cellular components known as cell fragments, which are devoid of nucleus, are also observed to be contractile and migratory in nature, independent of parent cell body. These platforms and findings can be further utilized to advance our current knowledge of the progression of these physiological and pathological processes and serve as diagnostic tools for the early identification of disease onset. Furthermore, based on these findings, strategies can be developed for early intervention to inhibit disease progression or devise bioengineered scaffolds for applications in tissue engineering.

Peptide-based biomaterials have gained much interest in various applications in drug delivery and tissue engineering in recent years, in large part due to their typically excellent biocompatibility and biodegradability. Composed of different amino acids, peptides can be designed with numerous sequences, providing flexibility and tunability in biomaterials. Peptides are easy to modify with small molecule drugs, inorganic components, and polymer chains to access multiple functions and tune properties relevant to biology and medicine. Stimuli-responsive peptide-based biomaterials can respond to environmental stimuli, such as light and ultrasound, in addition to local environmental factors, such as temperature, enzyme activity, and pH. Under environmental changes, these materials can be triggered to release therapeutic payloads, change conformations, or induce self-assembly in the target sites. In this work, I introduce the design, synthesis, and potential applications of several stimuli-responsive peptide-based biomaterials. The first half of this dissertation is based on enzyme-responsive, peptide-based biomaterials as extracellular matrix (ECM) mimics in tissue engineering. We synthesized linear and dendritic elastin-like peptides (ELPs) as crosslinkers and conjugated them with hyaluronic acid (HA) to form hydrogels. Trypsin was used as the enzyme trigger for cleaving the C-terminal lysine and to study how crosslinker topology affects enzymatic degradation. Hydrogels with dendritic ELPs degraded more slowly than linear ELPs, providing a novel strategy to tune the degradation rate of hydrogels as ECM mimics by the molecular design of crosslinker topology. Building on this peptide-polysaccharide platform for synthetic ECM design, we subsequently prepared hydrogels embedded with bioactive cryptic sites. These novel polymeric hydrogels mimicked native ECM cryptic sites by using depsipeptides that undergo an enzyme-triggered molecular rearrangement, "switching" from a non-functional epitope to a bioactive sequence. Mass spectrometry, 1H and 13C NMR spectroscopy, and fluorescence studies were applied to track structural changes in the peptide. SEM was used to image these polymer-peptide hybrid hydrogels. Finally, in vitro studies were conducted to evaluate cell interactions with the hydrogels. Switch peptide-modified alginate hydrogels showed increased cell adhesion upon induction of enzymatic activity, which provided a "gain of function" of the synthetic ECM. Critically, enzymes associated with the cells themselves could trigger the peptide switch and change in synthetic ECM behavior. With knowledge of stimuli-responsive peptide-based biomaterials applied in tissue engineering, I then studied how this system could be used in drug delivery by designing peptide-hydrogen sulfide (H2S) donor conjugates (PHDCs). H2S is a gasotransmitter that is produced endogenously, which has been explored in recent years with many potential therapeutical applications. We studied H2S release profiles in dual-enzyme-responsive PHDCs, with a further investigation into PHDC–Fe2+ complexes for potential tumor treatments via chemodynamic therapy. The PHDC–Fe2+ complexes were examined in a C6 glioma cell line, exhibiting an improved cell-killing effect compared with controls, by inducing toxic hydroxyl radical generation (•OH) via a Fenton reaction. To this end, we further discovered how side chains influence self-assembling nanostructures, H2S release profiles, and biological activities via three constitutionally isomeric PHDCs. Different morphologies and varied H2S release rates were observed, paving the way for tuning the properties of PHDCs by simple changes in molecular design. Finally, this dissertation discloses conclusions and future directions on stimuli-responsive peptide-based biomaterials using similar platforms with different designs in the drug delivery and tissue engineering fields. / Doctor of Philosophy / Peptides, short sequences of two or more amino acids linked by chemical bonds, are smaller versions of proteins. Forming naturally in nature, peptides are promising candidates in the design of biocompatible and biodegradable materials. To make these peptide-based materials "smart", certain sequences or functional groups are installed in the peptides, making them responsive to environmental changes, or stimuli. These external stimuli include light, ultrasound, temperature, enzyme activity, and pH changes. In this work, we have explored the design and synthesis of stimuli-responsive peptide-based biomaterials and their potential applications in tissue engineering and drug delivery. The first half of this dissertation focuses on the design and synthesis of two enzyme-responsive, peptide-based materials that function as extracellular matrix (ECM) mimics. The ECM is a three-dimensional microenvironment where cells reside, providing structural support and adhesive anchor points for cells. In the first system, we synthesized peptide-polysaccharide hydrogels with different peptide crosslinkers, comparing their enzymatic degradation performance to evaluate how peptide topology (architecture) influences degradation. A more branched topology led to a slower hydrogel degradation rate. To introduce biofunctionality into the ECM mimics, we embedded the second system with a "switchable" peptide sequence, which transformed from a non-functional peptide into a functional, bioactive epitope after being triggered by an enzyme. The functional peptide after the switch provided cell adhesion and increased cell spreading. The latter half of this dissertation explores the possibility of stimuli-responsive peptide-based biomaterials in drug delivery. We designed peptides that release hydrogen sulfide (H2S), a signaling gas is commonly known for its foul smell and toxicity, and studied the biological behaviors in cells. The peptide-H2S donor conjugates (PHDCs) were activated by the enzyme legumain, which cancer cells overproduce, leading to H2S release. With the combined treatment with Fe2+, the PHDC-Fe2+ system reduced cancer cell viability due to the high amount of hydroxyl radicals (•OH) generated by the Fenton reaction. This system may be a potential design platform for precise tumor treatments.

The tissue microenvironment is a complex living system containing heterogeneous mechanical and biophysical cues. Cellular components are surrounded by extracellular matrix and interstitial fluid, while transport of nutrients and biochemical factors is achieved via the vasculature. Each constituent of the tissue microenvironment can play a significant role in its ability to function normally. Many diseases including cancer have been linked with dysfunction in the tissue microenvironment; therefore an improved understanding of interaction between components of this complex system is needed. In vitro platforms mimicking the tissue microenvironment appear to provide the most promising avenue for studies of cell-cell and cell-matrix interactions as well as elucidation of the mechanisms leading to disease phenomena such as tumor metastasis. However, successful recapitulation of all three primary components of the tissue microenvironment in three dimensions has remained challenging. In particular, matching mechanical cues and biochemical transport to in vivo conditions is difficult because of lack of quantitative characterization of the physical properties and parameters of such platforms. In this work, extensive characterization of collagen I hydrogels, popular for use as extracellular matrix mimics, was performed in order to enable tuning to specific in vivo conditions. Additionally, perfusion of blood in a 3D tissue microenvironment platform fabricated using collagen hydrogels was characterized to enable future advances in in vitro modeling of the in vivo microenvironment. Finally, the tissue microenvironment platform is modified to enable biochemical gradients within the hydrogel and used to examine directed migration (chemotaxis) of human breast cancer cells in response to gradients in growth factor combined with varied stiffness and pore diameter of the extracellular matrix. / Ph. D.

The cellular microenvironment in vivo consists of both mechanical and chemical signals, which drive cell function and fate. These signals include the composition, architecture, and mechanical properties of the extracellular matrix (ECM), signaling molecules secreted by cells into their surroundings, as well as physical interactions between neighboring cells. Cells are able to interact with their surroundings through a number of different mechanisms such as remodeling of the ECM through adhesion, contraction, degradation, and deposition of proteins, as well as the secretion of pro- or anti-inflammatory molecules. In diseased states, where homeostasis has been perturbed, inflammatory signals are secreted which can modify the cellular microenvironment. Diseased states such as cancer and fibrosis are often associated with the excessive production of ECM proteins that subsequently lead to an increase in tissue stiffness and changes to ECM architecture. Such changes to the mechanical properties of the cellular microenvironment affect the cytoskeletal arrangement, migration and adhesion of both the parenchymal cells, as well as immune response cells, which migrate to the sites of injury. Further understanding of the inflammatory responses and their relationships to tissue stiffness and ECM architecture could aid in the development of novel strategies to predict diseases as well as to target and monitor therapies. Since inflammation and mechanical properties of the affected tissue are closely interlinked, obtaining a detailed understanding of the interplay between the properties of the microenvironment and the cells that reside within it will be very beneficial to obtain physiologically relevant information. We have investigated the combinatorial effects of matrix stiffness, and architecture in the presence of co-cultures of cells to determine the overall effect on cellular responses and phenotypes. We have conducted studies on co-cultures of cells in 2D and 3D environments to identify how cellular behavior is affected by dimensionality. / PHD / The cellular microenvironment in vivo consists of both mechanical and chemical signals, which drive cell function and fate. These signals include the composition and organization of the extracellular matrix (ECM), signaling molecules secreted by cells into their surroundings, as well as physical interactions between neighboring cells. Cells are able to interact with their surroundings through reorganization of the ECM and secretion of pro- or anti-inflammatory molecules. In diseased states, inflammatory signals are secreted which can modify the cellular microenvironment. Diseased states such as cancer and fibrosis are often associated with the excessive production of ECM proteins that subsequently lead to an increase in tissue stiffness and changes to ECM architecture. Such changes to the mechanical properties of the cellular microenvironment affect the function and behavior of cells within a given tissue. Further understanding of the inflammatory responses and their relationships to tissue stiffness and ECM architecture could aid in the development of novel strategies to predict diseases as well as to target and monitor therapies. Since inflammation and mechanical properties of the affected tissue are closely interlinked, obtaining a detailed understanding of the interplay between the properties of the microenvironment and the cells that reside within it will be very beneficial to obtain physiologically relevant information. We have investigated the combinatorial effects of matrix stiffness, and architecture in the presence of co-cultures of cells to determine the overall effect on cellular responses and phenotypes. We have conducted studies on co-cultures of cells in 2D and 3D environments to identify how cellular behavior is affected by dimensionality.

本研究的目的是針對退休金的長期負債以資產負債管理的方式提出有效的投資避險策略建議。在過去，傳統精算的資產負債管理大多採用確定投資模型（Deterministic Model），即以過去的經驗設立「精算假設」，但是這樣的假設無法精確的呈現未來的趨勢，所以本文的第一部份，便是根據過去的台灣總體經濟資料，建構一個退休基金的隨機投資模型（Stochastic Investment Model）。首先，我們以ECM（Error Correlation Model）模式建構出第一個投資模型，之後在精簡參數的考量下，建構第二個以因果關係為基礎的Causality投資模型，再以模型配適能力與預測能力比較兩模型，結果顯示Causality投資模型優於ECM投資模型。 　　有了投資模型，我們設定不同的退休金負債形式，如固定成長型負債MF、隨通貨膨脹成長M^R負債及隨max{固定成長比例，通貨膨脹}而成長的退休金負債M^L，以靜態避險的方式去求得各資產的最適配適比例。從模擬的結果中發現隨著到期日的增長，投資在風險性高報酬率佳的投資標的物上的比例也越來越高。另外，隨著負債固定成長比例f的增加，其M^L負債之期初資產配置額便越接近M^F負債之期初資產配置額。整體而言，我們由模擬中可得出，使用投資組合的投資方式優於單一資產投資的結論。 / In this study, we investigate the hedging strategies for pension liabilities by using Asset-Liability Management method. In the past, the traditional actuarial valuation usually does not take account of market value for both assets and liabilities. Most of the traditional actuarial valuation adopted the Deterministic Model, that is, setting the assumptions based on the experiences. However, it can not exactly show the trend in the future. In part one of this study, we build a stochastic investment model for the pension funds based on Taiwan Market data. First, we apply the first model : ECM( Error Correlation Model ). And then, we apply the second model : Causality Model under considering parsimonious parameterization. Finally, we compare the results of ECM with Causality Model on fitting and forecasting efficiency, and we find that Causality Model is better than ECM. With the investment model, we set some formulas of pension liabilities calculated to obtain the best fit proportion of each valuation by the static hedging. This involves finding optimal static hedging strategies to minimize riskiness of the investment portfolio relative to the liability. Overall, from the simulation results, for static hedging in these kinds of liabilities, investing in all three assets is a better strategy than investing in a single asset class. This confirms that the more assets we use, the more effectively we can hedge.

Synthetic biomaterials are constantly being developed and play central roles in contemporary strategies in regenerative medicine and tissue engineering as artificial extracellular microenvironments. Such scaffolds provide 2D- and 3D-support for interaction with cells and thus convey spatial and temporal control over their function and multicellular processes, such as differentiation and morphogenesis. A model fibrillar system with tunable viscoelastic properties, comprised of 2 native ECM components like collagen type I and the GAG heparin, is presented here. Although the individual components comply with the adhesive, mechanical and bioinductive requirements for artificial reconstituted ECMs, their interaction and structural characterization remains an intriguing conundrum. The aim of the work was to analyze and structurally characterize a xenogeneic in vitro cell culture scaffold reconstituted from two native ECM components, collagen type I and the highly negatively charged glycosaminoglycan heparin. Utilizing a broad spectrum of structural analysis it could be shown that pepsin-solubilized collagen type I fibrils, reconstituted in vitro in the presence of heparin, exhibit an unusually thick and straight shape, with a non-linear dependence in size distribution, width-to-length ratio, and morphology over a wide range of GAG concentrations. The experiments imply a pronounced impact of the nucleation phase on the cofibril morphology as a result of the strong electrostatic interaction of heparin with atelocollagen. Heparin is assumed to stabilize the collagen-GAG complexes and to enhance their parallel accretion during cofibrillogenesis, furthermore corroborated by the heparin quantitation data showing the GAG to be intercalated as a linker molecule with a specific binding site inside the cofibrils. In addition, the exerted morphogenic effect of the GAG, appears to be influenced by factors as degree of sulfation, charge, and concentration. Further detailed structural analysis of the PSC-heparin gels using TEM and SFM showed a hierarchy involving 3 different structural levels and banding patterns in the system: asymmetric segment longspacing (SLS) fibrils and symmetric segments with an average periodicity (AP) of 250 - 260 nm, symmetric fibrous longspacing (FLS IV) nanofibrils with AP of 165 nm, and cofibrils exhibiting an asymmetric D-periodicity of 67 nm with a striking resemblance to the native collagen type I banding pattern. The intercalation of the high negatively charged heparin in the cofibrils was suggested as the main trigger for the hierarchical formation of the polymorphic structures. We also proposed a model explaining the unexpected presence of a symmetric and asymmetric form in the system and the principles governing the symmetric or asymmetric fate of the molecules. The last section of the experiments showed that the presence of telopeptides and heparin both had significant effects on the structural and mechanical characteristics of in vitro reconstituted fibrillar collagen type I. The implemented structural analysis showed that the presence of telopeptides in acid soluble collagen (ASC) impeded the reconstitution of D-periodic collagen fibrils in the presence of heparin, leaving behind only a symmetric polymorphic form with a repeating unit of 165 nm (FLS IV). Further x-ray diffraction analysis of both telopeptide-free and telopeptide-intact collagen fibrils showed that the absence of the flanking non-helical termini in pepsin-solubilized collagen (PSC) resulted in a less compact packing of triple helices of atelocollagen with an increase of interhelical distance from 1.0 to 1.2 nm in dried samples. The looser packing of the triple helices was accompanied by a decrease in bending stiffness of the collagen fibrils, which demonstrated that the intercalated heparin cannot compensate for the depletion of telopeptides. Based on morphological, structural and mechanical differences between ASC and PSC-heparin fibrils reported here, we endorsed the idea that heparin acts as an intrafibrillar cross-linker which competed for binding sites at places along the atelocollagen helix that are occupied in vivo by telopeptides in the fibrillar collagen type I. The performed studies are of particular interest for understanding and gaining control over a rather versatile and already exploited xenogeneic cell culture system. The reconstituted cofibrils with their unusual morphology and GAG intercalation – a phenomenon not reported in vivo – are expected to exhibit interesting biochemical behavior as a biomaterial for ECM scaffolds. Varying the experimental conditions, extent of telopeptide removal, and heparin concentration provides powerful means to control the kinetics, structure, dimensions, as well as mechanical properties of the system which is particularly important for predicting a certain cell behavior towards the newly developed matrix. The GAG intercalation could be interesting for studies with required long-term 'release upon demand' of the GAG, as well as native binding and stabilization of growth factors, cytokines, chemokines, thus providing a secondary tool to control cell signaling and fate, and later on tissue morphogenesis. / Synthetische Biomaterialien werden stetig weiterentwickelt und spielen als künstliche Mikroumgebungen eine zentrale Rolle in den modernen Strategien der regenerativen Medizin und des Tissue Engineerings. Solche sogenannten Scaffolds liefern eine 2D- und 3D-Struktur zur Interaktion mit Zellen und üben somit eine räumliche und zeitliche Kontrolle auf ihre Funktion und multizelluläre Prozesse aus, wie die Differenzierung und Morphogenese. Obwohl häufig die adhäsiven, mechanischen und bioinduzierenden Eigenschaften von Einzelkomponenten aus natürlichen Bestandteilen der extrazellulären Matrix (ECM) rekonstituierten Trägerstrukturen bekannt sind, bleiben die funktionalen und strukturellen Auswirkungen in Mehrkomponentensystemen eine faszinierende Fragestellung. Das Ziel der Arbeit war die Analyse und die strukturelle Charakterisierung einer xenogenen in vitro Zellkultur-Trägerstruktur, die aus den zwei nativen ECM Komponenten Kollagen Typ I und das stark negativ geladene Glykosaminoglykan (GAG) Heparin rekonstituiert wurde. Unter Nutzung eines breiten Spektrums von Methoden zur strukturellen Analyse konnte gezeigt werden, dass im Beisein von Heparin rekonstituierte Pepsin-gelöste Kollagen Typ I Fibrillen eine ungewöhnlich dicke und gerade Form, mit nichtlinearen Abhängigkeiten der Größenverteilung, des Breite-zu-Länge Verhältnises und der Morphologie für eine Reihe von GAG Konzentrationen, aufweisen. Die Experimente deuten auf eine besondere Wirkung der Nukleierungsphase auf die Kofibrillmorphologie hin, als Folge der starken elektrostatischen Inteaktionen Heparins mit Atelokollagen. Es wird angenommen, dass Heparin die Komplexe aus Kollagen-GAG stabilisiert, die parallele Anlagerung während der Kofibrillogenese verbessert und dass überdies, belegt durch Heparin Quantitätsdaten, als Verbindungsmolekül mit einer spezifischen Anbindungsstelle innerhalb der Kofibrillen eingelagert wird. Darüber hinaus scheint der ausgeübte morphogene Effekt des GAGs Heparins von Faktoren wie Grad der Sulfatierung, Ladung und Konzentration abzuhängen. Weitere detailierte Strukturanalysen der PSC - Heparin Gele mit TEM und SFM zeigten eine Hierarchie mit drei unterschiedlichen strukturellen Ebenen und Bandmustern im System: asymmetrisch segmentierte, weitabständige Fibrillen (SLS) und symmetrische Segmente mit einem AP von 250-260 nm, symmetrische fibrose weitabständige (FLS IV) Nanofibrillen mit einem AP von von 165 nm und Kofibrillen asymmetrischer D-Periodizität von 67 nm, die eine erstaunliche Ähnlichkeit zum natürlichen Kollagen Typ I Bandmuster haben. Die Einlagerung des sehr negativ geladenen Heparins in die Kofibrillen wurde als Hauptauslöser der hierarchischen Formation der polymorphen Strukturen betrachtet. Wir schlugen ebenso ein Model vor, welches sowohl das unerwartete Vorhandensein symmetrischer und asymmetrischer Formen im System als auch die Regeln erklärt, die das symmetrische oder asymmetrische Schicksal der Moleküle steuern. Der letzte Abschnitt der Experimente zeigte, dass die Anwesenheit der Telopeptide und Heparins eine signifikante Wirkung auf die strukturellen und mechanischen Charakteristika der in vitro rekonstituierten Kollagen Typ I Fibrillen hatte. Die durchgeführten Strukturanalysen zeigten außerdem, dass die Anwesenheit der Telopeptide in säurelöslichem Kollagen (ASC) die Rekonstitution D-periodischer Kollagenfibrillen mit Heparin verhinderte, sodass nur symmetrisch polymorphe Formen mit einer Wiederholeinheit von 165 nm möglich waren (FLS IV). Weitere Messungen der Telopeptid-freien und Telopeptid-intakten Kollagenfibrillen mit Röntgendiffraktometrie ergaben, dass die Abwesenheit der nicht-helix-strukturierten Enden in Pepsin-gelöstem Kollagen (PSC) zu einer weniger kompakten Anordnung der Tripelhelices von Atelokollagen führte. Der interhelix Abstand erhöhte sich von 1,0 zu 1,2 nm für getrocknete Proben. Das zeigt, dass die losere Anordnung der Tripelhelices einhergeht mit der Verringerung der Biege-Elastizitäts-module der Kollagenfibrillen,. Basierend auf den hier vorgestellten morphologischen, strukturellen und mechanischen Unterschieden zwischen ASC und PSC-Heparin Fibrillen wird die Idee unterstützt, dass Heparin als intrafibrillärer Vernetzer fungiert und an Bindungsstellen der Helix bindet, welche in vivo bei Kollagen Typ I Fibrillen durch Telopeptide besetzt sind. Die durchgeführten Studien sind von besonderem Interesse für das Verständnis und die Steuerung eines sehr vielseitigen und bereits verwendeten xenogenes Zellkultursystem für das Tissue Engineering. Von den rekonstituierten Kofibrillen mit ihrer ungewöhnlichen Morphologie und GAG Einlagerung - ein in vivo nicht bekanntes Phänomen - erwartet man, dass sie ein intressantes biochemisches Verhalten als Biomaterial für ECM Scaffolds zeigen. Variationen der experimentellen Bedingungen, des Ausmaßes der Telopeptidentfernung und der Heparinkonzentration liefern vielfältige Möglichkeiten um die Kinetik, Struktur, Dimension sowie die mechanischen Eigenschaften des Systems zu kontrollieren. Damit sollte es möglich sein, ein bestimmtes Zellverhalten gegenüber der neu entwickelten Matrix vorherzusagen. Die GAG-Einlagerung bietet interessante Optionen für eine langfristige Freisetzung des GAGs 'on demand', sowie die native Bindung und Stabilisierung von Wachstumsfaktoren, Cytokinen, Chemokinen, womit zusätzlich Zellsignalisierung und -schicksal und später Gewebemorphogenese kontrolliert werden kann.

L’organisation des connaissances est une discipline investie par des bibliothécaires, documentalistes, archivistes spécialistes de l’information, informaticiens et tous professionnels de documents. Elle englobe toutes activités, études et recherches qui élaborent et traitent les processus d’organisation et de présentation des ressources documentaires utiles dans une organisation. Dans ce contexte, le projet ANR Miipa-Doc a pour objectifs d’explorer des nouvelles méthodes d’indexation ascendantes, en utilisant des termes descripteurs formulés par les individus plutôt que choisis parmi une liste préétablie, pour l’organisation des contenus documentaires complexes au sein des entreprises de large taille, et concevoir l’architecture logicielle correspondante.Dans ce projet notre contribution consiste à gérer l’hétérogénéité d’un système d’information d’organisation des contenus documentaires, basé sur une approche orientée métier et un SOC (système d’organisation des connaissances) folksonomique à facette. Nous proposons dans cette gestion une approche incrémentale dirigée par les modèles, issue de l’IDM (ingénierie dirigée par les modèles), basée sur des méta-modèles pour garantir l’aspect d’évolutivité. Après l’implémentation du prototype HyperTaging qui met en place ces deux approches, nous proposons un processus d’évaluation permet de positionner ce prototype et tous SI de classification documentaire dans l’environnement des ECM, en se basant sur des critères d’évaluation fins et particuliers. / The knowledge organization is invested by librarians, archivists, information specialists, IT professionals and all discipline of document. It includes all activities, studies and research which develop and treat organization process and presentation of relevant information resources in an organization. In this context the Miipa-Doc project aims to explore new ascendants indexing methods, using descriptors made by individuals rather than selected given list for complex contained in the organization document, in large size companies, and design the corresponding software architecture.Our contribution in this project is to manage the heterogeneity of an information system of document organization, based on a business-oriented approach and a KOS (knowledge organization system) of folksonomy facet. We propose an incremental approach this management model driven, outcome of MDE (Model Driven Engineering), based on meta-models to ensure scalability appearance. After implementing the HyperTaging prototype, that implements both approaches, we propose an evaluation process used to position the prototype and all IS of documentary classification in the environment of ECM based on purposes of delicate and particular evaluation criteria.

L’organisation des connaissances est une discipline investie par des bibliothécaires, documentalistes, archivistes spécialistes de l’information, informaticiens et tous professionnels de documents. Elle englobe toutes activités, études et recherches qui élaborent et traitent les processus d’organisation et de présentation des ressources documentaires utiles dans une organisation. Dans ce contexte, le projet ANR Miipa-Doc a pour objectifs d’explorer des nouvelles méthodes d’indexation ascendantes, en utilisant des termes descripteurs formulés par les individus plutôt que choisis parmi une liste préétablie, pour l’organisation des contenus documentaires complexes au sein des entreprises de large taille, et concevoir l’architecture logicielle correspondante.Dans ce projet notre contribution consiste à gérer l’hétérogénéité d’un système d’information d’organisation des contenus documentaires, basé sur une approche orientée métier et un SOC (système d’organisation des connaissances) folksonomique à facette. Nous proposons dans cette gestion une approche incrémentale dirigée par les modèles, issue de l’IDM (ingénierie dirigée par les modèles), basée sur des méta-modèles pour garantir l’aspect d’évolutivité. Après l’implémentation du prototype HyperTaging qui met en place ces deux approches, nous proposons un processus d’évaluation permet de positionner ce prototype et tous SI de classification documentaire dans l’environnement des ECM, en se basant sur des critères d’évaluation fins et particuliers. / The knowledge organization is invested by librarians, archivists, information specialists, IT professionals and all discipline of document. It includes all activities, studies and research which develop and treat organization process and presentation of relevant information resources in an organization. In this context the Miipa-Doc project aims to explore new ascendants indexing methods, using descriptors made by individuals rather than selected given list for complex contained in the organization document, in large size companies, and design the corresponding software architecture.Our contribution in this project is to manage the heterogeneity of an information system of document organization, based on a business-oriented approach and a KOS (knowledge organization system) of folksonomy facet. We propose an incremental approach this management model driven, outcome of MDE (Model Driven Engineering), based on meta-models to ensure scalability appearance. After implementing the HyperTaging prototype, that implements both approaches, we propose an evaluation process used to position the prototype and all IS of documentary classification in the environment of ECM based on purposes of delicate and particular evaluation criteria.