Elastin-targeted nanoparticles delivering doxycycline mitigate cytokine storm and reduce immune cell infiltration in LPS-mediated lung inflammation.

Background And Purpose: Cytokine storm invoked during acute and chronic lung injury promotes alveolar damage and remodeling. The current study shows that degraded elastin-targeted nanoparticles releasing doxycycline (Doxy NPs) are potent in mitigating cytokines storm, migration of immune cells in the lungs, and inhibiting inflammasome pathways in the LPS mouse model.

Experimental Approach: Cytokine storm and lung injury were induced using LPS and elastase in C57BL/6 mice (rodent model for emphysema).

Full-field strain mapping of healthy and pathological mouse aortas using stereo digital image correlation.

The murine aorta is a complex, heterogeneous structure that undergoes large and sometimes asymmetrical deformations under loading. For analytical convenience, mechanical behavior is predominantly described using global quantities that fail to capture critical local information essential to elucidating aortopathic processes. Here, in our methodological study, we used stereo digital image correlation (StereoDIC) to measure the strain profiles of speckle-patterned healthy and elastase-infused, pathological mouse aortas submerged in a temperature-controlled liquid medium.

Increased TGFβ1 and SMAD3 Contribute to Age-Related Aortic Valve Calcification.

Aims: Calcific aortic valve disease (CAVD) is a progressive heart disease that is particularly prevalent in elderly patients. The current treatment of CAVD is surgical valve replacement, but this is not a permanent solution, and it is very challenging for elderly patients. Thus, a pharmacological intervention for CAVD may be beneficial.

Targeted delivery of pentagalloyl glucose inhibits matrix metalloproteinase activity and preserves elastin in emphysematous lungs.

Background: Elastin degradation has been established as one of the driving factors of emphysema. Elastin-derived peptides (EDPs) are shown to act as a chemoattractant for monocytes. Effectively shielding elastin from elastolytic damage and regenerating lost elastin are two important steps in improving the mechanical function of damaged lungs.

Osteoclast-Mediated Cell Therapy as an Attempt to Treat Elastin Specific Vascular Calcification.

Inflammation and stiffness in the arteries is referred to as vascular calcification. This process is a prevalent yet poorly understood consequence of cardiovascular disease and diabetes mellitus, comorbidities with few treatments clinically available. Because this is an active process similar to bone formation, it is hypothesized that osteoclasts (OCs), bone-resorbing cells in the body, could potentially work to reverse existing calcification by resorbing bone material.

Effect of all-trans retinoic acid and pentagalloyl glucose on smooth muscle cell elastogenesis.

Background: The main objective of tissue engineering is to fabricate a tissue construct that mimics native tissue both biologically and mechanically. A recurring problem for tissue-engineered blood vessels (TEBV) is deficient elastogenesis from seeded smooth muscle cells. Elastin is an integral mechanical component in blood vessels, allowing elastic deformation and retraction in response to the shear and pulsatile forces of the cardiac system.

Null strain analysis of submerged aneurysm analogues using a novel 3D stereomicroscopy device.

To measure the inhomogeneous 3D-strain fields present during inflation-extension testing of physiologically submerged micro-aneurysms, a Stereo Digital Image Correlation (StereoDIC) microscopy system is developed that revolves 15 stereo-angle cameras around a centrally-mounted target. Calibration is performed using submerged dot patterns and system accuracy verified using strain and deformation analyses for rigid body motions of speckle-patterned, micro-aneurysmal surrogates. In terms of the Green-Lagrange strain tensor and the 3D displacement fields, the results are stable even after 120 minutes, with maxima in both strain bias and strain standard deviation less than 2E-03 for all components, and micron-level displacement standard deviation.

Reversal of Vascular Calcification and Aneurysms in a Rat Model Using Dual Targeted Therapy with EDTA- and PGG-Loaded Nanoparticles.

Degeneration of elastic lamina and vascular calcification are common features of vascular pathology such as aortic aneurysms. We tested whether dual therapy with targeted nanoparticles (NPs) can remove mineral deposits (by delivery of a chelating agent, ethylene diamine tetraacetic acid (EDTA)) and restore elastic lamina (by delivery of a polyphenol, pentagalloyl glucose (PGG)) to reverse moderate aneurysm development. EDTA followed by PGG NP delivery led to reduction in macrophage recruitment, matrix metalloproteinase (MMP) activity, elastin degradation and calcification in the aorta as compared to delivery of control blank NPs.

Nitric oxide stimulates matrix synthesis and deposition by adult human aortic smooth muscle cells within three-dimensional cocultures.

Vascular diseases are characterized by the over-proliferation and migration of aortic smooth muscle cells (SMCs), and degradation of extracellular matrix (ECM) within the vessel wall, leading to compromise in cell-cell and cell-matrix signaling pathways. Tissue engineering approaches to regulate SMC over-proliferation and enhance healthy ECM synthesis showed promise, but resulted in low crosslinking efficiency. Here, we report the benefits of exogenous nitric oxide (NO) cues, delivered from S-Nitrosoglutathione (GSNO), to cell proliferation and matrix deposition by adult human aortic SMCs (HA-SMCs) within three-dimensional (3D) biomimetic cocultures.

Osteogenic responses in fibroblasts activated by elastin degradation products and transforming growth factor-beta1: role of myofibroblasts in vascular calcification.

Our objective was to establish the role of fibroblasts in medial vascular calcification, a pathological process known to be associated with elastin degradation and remodeling. Rat dermal fibroblasts were treated in vitro with elastin degradation products and transforming growth factor (TGF)-beta1, factors usually present in deteriorated matrix environments. Cellular changes were monitored at the gene and protein level by reverse transcriptase-polymerase chain reaction, enzyme-linked immunosorbent assay, immunofluorescence, and von Kossa staining for calcium deposits.

Elastin stabilization for treatment of abdominal aortic aneurysms.

Background: Maintaining the integrity of arterial elastin is vital for the prevention of abdominal aortic aneurysm (AAA) development. We hypothesized that in vivo stabilization of aortic elastin with pentagalloyl glucose (PGG), an elastin-binding polyphenol, would interfere with AAA development.

Methods And Results: Safety and efficacy of PGG treatment were first tested in vitro using cytotoxicity, elastin stability, and PGG-elastin interaction assays.

In vivo cellular repopulation of tubular elastin scaffolds mediated by basic fibroblast growth factor.

In vivo tissue engineering has been explored as a method to repopulate scaffolds with autologous cells to create a functional, living, and non-immunogenic tissue substitute. In this study, we describe an approach to in vivo cellular repopulation of a tissue-derived tubular elastin scaffold. Pure elastin scaffolds were prepared from porcine carotid arteries (elastin tubes).

Toward cell therapy for vascular calcification: osteoclast-mediated demineralization of calcified elastin.

Background: Elastin-oriented vascular calcification is a clinically significant feature, which involves formation of ectopic bone-like structures. Taking advantage of the similarities between arterial calcification and bone regulation, our hypothesis was that therapeutic approaches for limitation of vascular calcification could be developed using site-specific delivery of autologous osteoclasts. In the present paper, we tested the hypothesis that bone-marrow-derived osteoclasts have the ability to demineralize calcified elastin, without significant alterations in elastin integrity.

Glycosaminoglycan-targeted fixation for improved bioprosthetic heart valve stabilization.

Numerous crosslinking chemistries and methodologies have been investigated as alternative fixatives to glutaraldehyde (GLUT) for the stabilization of bioprosthetic heart valves (BHVs). Particular attention has been paid to valve leaflet collagen and elastin stability following fixation. However, the stability of glycosaminoglycans (GAGs), the primary component of the spongiosa layer of the BHV, has been largely overlooked despite recent evidence provided by our group illustrating their structural and functional importance.

Structural requirements for stabilization of vascular elastin by polyphenolic tannins.

Elastin-associated degeneration and calcification are potential causes of long-term failure of glutaraldehyde (Glut) fixed tissue bioprostheses used in cardiovascular surgery. This vulnerability may be attributed to the inability of Glut to cross-link and adequately protect vascular elastin from enzymatic attack. Tannic acid (TA), a poly galloyl glucose (Glc), is compatible with Glut fixation, binds to vascular elastin, improves resistance to degradation and reduces in vivo calcification.

Elastin calcification in the rat subdermal model is accompanied by up-regulation of degradative and osteogenic cellular responses.

Calcification of vascular elastin occurs in patients with arteriosclerosis, renal failure, diabetes, and vascular graft implants. We hypothesized that pathological elastin calcification is related to degenerative and osteogenic mechanisms. To test this hypothesis, the temporal expression of genes and proteins associated with elastin degradation and osteogenesis was examined in the rat subdermal calcification model by quantitative real-time reverse transcription-polymerase chain reaction and specific protein assays.

Stability and function of glycosaminoglycans in porcine bioprosthetic heart valves.

Glycosaminoglycans (GAGs) are important structural and functional components in native aortic heart valves and in glutaraldehyde (Glut)-fixed bioprosthetic heart valves (BHVs). However, very little is known about the fate of GAGs within the extracellular matrix of BHVs and their contribution to BHV longevity. BHVs used in heart valve replacement surgery have limited durability due to mechanical failure and pathologic calcification.

Elastin-derived peptides and TGF-beta1 induce osteogenic responses in smooth muscle cells.

Elastin degradation associated with matrix metalloproteinase activity is a cell-mediated process, observed in almost all types of vascular calcification. In this study, we tested the hypothesis that elastin-derived peptides induce an osteogenic response in vascular smooth muscle cells (SMCs) in vitro. Using RT-PCR and specific protein assays, we demonstrated that rat aortic SMCs incubated with elastin peptides exhibited an increased expression of the 67 kDa elastin laminin receptor (ELR) and matrix metalloproteinase-2 and typical bone proteins, such as core binding factor alpha-1, osteocalcin, and alkaline phosphatase.

Triglycidylamine crosslinking of porcine aortic valve cusps or bovine pericardium results in improved biocompatibility, biomechanics, and calcification resistance: chemical and biological mechanisms.

We investigated a novel polyepoxide crosslinker that was hypothesized to confer both material stabilization and calcification resistance when used to prepare bioprosthetic heart valves. Triglycidylamine (TGA) was synthesized via reacting epichlorhydrin and NH(3). TGA was used to crosslink porcine aortic cusps, bovine pericardium, and type I collagen.

Elastin degradation and calcification in an abdominal aorta injury model: role of matrix metalloproteinases.

Background: Elastin calcification is a widespread feature of vascular pathology, and circumstantial evidence exists for a correlation between elastin degradation and calcification. We hypothesized that matrix metalloproteinase (MMP)-mediated vascular remodeling plays a significant role in elastin calcification.

Methods And Results: In the present studies, we determined that short-term periadventitial treatment of the rat abdominal aorta with low concentrations of calcium chloride (CaCl2) induced chronic degeneration and calcification of vascular elastic fibers in the absence of aneurysm formation and inflammatory reactions.

Novel porous aortic elastin and collagen scaffolds for tissue engineering.

Decellularized vascular matrices are used as scaffolds in cardiovascular tissue engineering because they retain their natural biological composition and three-dimensional (3-D) architecture suitable for cell adhesion and proliferation. However, cell infiltration and subsequent repopulation of these scaffolds was shown to be unsatisfactory due to their dense collagen and elastic fiber networks. In an attempt to create more porous structures for cell repopulation, we selectively removed matrix components from decellularized porcine aorta to obtain two types of scaffolds, namely elastin and collagen scaffolds.

Involvement of matrix metalloproteinases and tenascin-C in elastin calcification.

Elastin degeneration and calcification occur in many cardiovascular diseases, including medial arterial elastocalcinosis, atherosclerosis, and bioprosthetic heart valve mineralization. In the present study, we tested the hypothesis that the onset and progression of elastin-oriented calcification is associated with matrix remodeling and elastin degradation events. We studied whether aluminum ions inhibit elastin calcification by reducing elastin degradation and altering remodeling events.

Construction of high-density bacterial colony arrays and patterns by the ink-jet method.

We have developed a method for fabricating bacterial colony arrays and complex patterns using commercially available ink-jet printers. Bacterial colony arrays with a density of 100 colonies/cm(2) were obtained by directly ejecting Escherichia coli (E. coli) onto agar-coated substrates at a rapid arraying speed of 880 spots per second.

Extracellular matrix degrading enzymes are active in porcine stentless aortic bioprosthetic heart valves.

Glutaraldehyde-fixed porcine aortic valve tissues are widely used for heart valve replacement surgery in the form of bioprosthetic heart valves (BHVs). The durability of BHVs in the clinical setting is limited by tissue degeneration, mechanical failure, and calcification. BHVs rely on the putative ability of glutaraldehyde to render biologic tissues metabolically inert and fully resistant to enzymatic attack.

Degeneration of bioprosthetic heart valve cusp and wall tissues is initiated during tissue preparation: an ultrastructural study.

Background And Aim Of The Study: Chronic tissue degeneration is a major factor in the failure of porcine bioprosthetic heart valves. Stabilization with glutaraldehyde (GA) has become the standard in preparation of bioprosthetic heart valves, but there is increasing evidence that GA does not effectively stabilize all tissue structures, specifically glycosaminoglycans (GAGs). The study aim was to establish the status of GAGs in bioprosthetic heart valves and to ascertain whether degeneration of the extracellular matrix (ECM) is initiated during preparation of porcine tissues for use as bioprosthetic heart valves.