Impact of Cyclic Strain on Elastin Synthesis in a 3D Human Myometrial Culture Model.

The synthesis and assembly of mature, organized elastic fibers remains a limitation to the clinical use of many engineered tissue replacements. There is a critical need for a more in-depth understanding of elastogenesis regulation for the advancement of methods to induce and guide production of elastic matrix structures in engineered tissues that meet the structural and functional requirements of native tissue. The dramatic increase in elastic fibers through normal pregnancy has led us to explore the potential role of mechanical stretch in combination with pregnancy levels of the steroid hormones 17ß-estradiol and progesterone on elastic fiber production by human uterine myometrial smooth muscle cells in a three-dimensional (3D) culture model. Opposed to a single strain regimen, we sought to better understand how the amplitude and frequency parameters of cyclic strain influence elastic fiber production in these myometrial tissue constructs (MTC). Mechanical stretch was applied to MTC at a range of strain amplitudes (5%, 10%, and 15% at 0.5 Hz frequency) and frequencies (0.1 Hz, 0.5 Hz, 1 Hz, and constant 0 Hz at 10% amplitude), with and without pregnancy-level hormones, for 6 days. MTC were assessed for cell proliferation, matrix elastin protein content, and expression of the main elastic fiber genes, tropoelastin (ELN) and fibrillin-1 (FBN1). Significant increases in elastin protein and ELN and FBN1 mRNA were produced from samples subjected to a 0.5 Hz, 10% strain regimen, as well as samples stretched at higher amplitude (15%, 0.5 Hz) and higher frequency (1 Hz, 10%); however, no significant effects because of third-trimester mimetic hormone treatment were determined. These results establish that a minimum level of strain is required to stimulate the synthesis of elastic fiber components in our culture model and show this response can be similarly enhanced by increasing either the amplitude or frequency parameter of applied strain. Further, our results demonstrate strain alone is sufficient to stimulate elastic fiber production and suggest hormones may not be a significant factor in regulating elastin synthesis. This 3D culture model will provide a useful tool to further investigate mechanisms underlying pregnancy-induced de novo elastic fiber synthesis and assembly by uterine smooth muscle cells.

A non-canonical role of ELN protects from cellular senescence by limiting iron-dependent regulation of gene expression.

The ELN gene encodes tropoelastin which is used to generate elastic fibers that insure proper tissue elasticity. Decreased amounts of elastic fibers and/or accumulation of bioactive products of their cleavage, named elastokines, are thought to contribute to aging. Cellular senescence, characterized by a stable proliferation arrest and by the senescence-associated secretory phenotype (SASP), increases with aging, fostering the onset and progression of age-related diseases and overall aging, and has so far never been linked with elastin. Here, we identified that decrease in ELN either by siRNA in normal human fibroblasts or by knockout in mouse embryonic fibroblasts results in premature senescence. Surprisingly this effect is independent of elastic fiber degradation or elastokines production, but it relies on the rapid increase in HMOX1 after ELN downregulation. Moreover, the induction of HMOX1 depends on p53 and NRF2 transcription factors, and leads to an increase in iron, further mediating ELN downregulation-induced senescence. Screening of iron-dependent DNA and histones demethylases revealed a role for histone PHF8 demethylase in mediating ELN downregulation-induced senescence. Collectively, these results unveil a role for ELN in protecting cells from cellular senescence through a non-canonical mechanism involving a ROS/HMOX1/iron accumulation/PHF8 histone demethylase pathway reprogramming gene expression towards a senescence program.

Liquid to solid transition of elastin condensates.

Liquid-liquid phase separation of tropoelastin has long been considered to be an important early step in the complex process of elastin fiber assembly in the body and has inspired the development of elastin-like peptides with a wide range of industrial and biomedical applications. Despite decades of study, the material state of the condensed liquid phase of elastin and its subsequent maturation remain poorly understood. Here, using a model minielastin that mimics the alternating domain structure of full-length tropoelastin, we examine the elastin liquid phase. We combine differential interference contrast (DIC), fluorescence, and scanning electron microscopy with particle-tracking microrheology to resolve the material transition occurring within elastin liquids over time in the absence of exogenous cross-linking. We find that this transition is accompanied by an intermediate stage marked by the coexistence of insoluble solid and dynamic liquid phases giving rise to significant spatial heterogeneities in material properties. We further demonstrate that varying the length of the terminal hydrophobic domains of minielastins can tune the maturation process. This work not only resolves an important step in the hierarchical assembly process of elastogenesis but further contributes mechanistic insight into the diverse repertoire of protein condensate maturation pathways with emerging importance across biology.

Globule and fiber formation with elastin-like polypeptides: a balance of coacervation and crosslinking.

Elastic fiber assembly is a complex process that requires the coacervation and cross-linking of the protein building block tropoelastin. To date, the order, timing, and interplay of coacervation and crosslinking is not completely understood, despite a great number of advances into understanding the molecular structure and functions of the many proteins involved in elastic fiber assembly. With a simple in vitro model using elastin-like polypeptides and the natural chemical crosslinker genipin, we demonstrate the strong influence of the timing and kinetics of crosslinking reaction on the coacervation, crosslinking extent, and resulting morphology of elastin. We also outline a method for analyzing elastin droplet network formation as a heuristic for measuring the propensity for elastic fiber formation. From this we show that adding crosslinker during peak coacervation dramatically increases the propensity for droplet network formation.

Visualization of elastin using cardiac magnetic resonance imaging after myocardial infarction as inflammatory response.

The aim of this study was to investigate the merits of magnetic resonance imaging (MRI) using an elastin-binding contrast agent after myocardial infarction in mouse models with deletions of monocyte populations. Permanent ligation of the left anterior descending (LAD) artery was conducted in 10 wild-type mice and 10 each of three knockout models: CX3CR-/-, CCR2-/-, and MCP-1-/-. At 7 days and 30 days after permanent ligation, cardiac MRI was performed with a 7 T-Bruker horizontal scanner for in vivo detection of elastin with an elastin/tropoelastin-specific contrast agent (ESMA). Histology was performed with staining for elastin, collagen I and III, and F4/80. Real-time PCR was conducted to quantify the expression of genes for collagen I and III, F4/80, and tumor necrosis factor alpha (TNFα). Histological and ESMA-indicated elastin areas were strongly correlated (r = 0.8). 30 days after permanent ligation, CCR2-deficient mice demonstrated higher elastin levels in the scar relative to MCP-1-/- (p < 0.04) and wild-type mice (p < 0.02). The ejection fraction was lower in CCR2-deficient mice. In vivo MRI in mouse models of MI can detect elastin deposition after myocardial infarction, highlighting the pivotal role of elastin in myocardial remodeling in mouse models with deletions of monocyte populations.

Domains 12 to 16 of tropoelastin promote cell attachment and spreading through interactions with glycosaminoglycan and integrins alphaV and alpha5beta1.

Elastin is an extracellular matrix component with key structural and biological roles in elastic tissues. Interactions between resident cells and tropoelastin, the monomer of elastin, underpin elastin's regulation of cellular processes. However, the nature of tropoelastin-cell interactions and the contributions of individual tropoelastin domains to these interactions are only partly elucidated. In this study, we identified and characterized novel cell-adhesive sites in the tropoelastin N-terminal region between domains 12 and 16. We found that this region interacts with αV and α5ß1 integrin receptors, which mediate cell attachment and spreading. A peptide sequence from within this region, spanning domains 14 to mid-domain 16, binds heparan sulfate through electrostatic interactions with peptide lysine residues and induces conformational ordering of the peptide. We propose that domains 14-16 direct initial cell attachment through cell-surface heparan sulfate glycosaminoglycans, followed by αV and α5ß1 integrin-promoted attachment and spreading on domains 12-16 of tropoelastin. These findings advance our mechanistic understanding of elastin matrix biology, with the potential to enhance tissue regenerative outcomes of elastin-based materials.

The evolutionary background and functional consequences of the rs2071307 polymorphism in human tropoelastin.

Elastin is a major polymeric protein of the extracellular matrix, providing critical properties of extensibility and elastic recoil. The rs2071307 genomic polymorphism, resulting in the substitution of a serine for a glycine residue in a VPG motif in tropoelastin, has an unusually high minor allele frequency in humans. A consequence of such allelic heterozygosity would be the presence of a heterogeneous elastin polymer in up to 50% of the population, a situation which appears to be unique to Homo sapiens. VPG motifs are extremely common in hydrophobic domains of tropoelastins and are the sites of transient ß-turns that are essential for maintaining the conformational flexibility required for its function as an entropic elastomer. Earlier data demonstrated that single amino acid substitutions in tropoelastin can have functional consequences for polymeric elastin, particularly when present in mixed polymers. Here, using NMR and molecular dynamics approaches, we show the rs2071307 polymorphism reduces local propensity for ß-turn formation, with a consequent increase in polypeptide hydration and an expansion of the conformational ensemble manifested as an increased hydrodynamic radius, radius of gyration and asphericity. Furthermore, this substitution affects functional properties of polymeric elastin, particularly in heterogeneous polymers mimicking allelic heterozygosity. We discuss whether such effects, together with the unusually high minor allele frequency of the polymorphism, could imply some some evolutionary advantage for the heterozygous state.

Elastases and elastokines: elastin degradation and its significance in health and disease.

Elastin is an important protein of the extracellular matrix of higher vertebrates, which confers elasticity and resilience to various tissues and organs including lungs, skin, large blood vessels and ligaments. Owing to its unique structure, extensive cross-linking and durability, it does not undergo significant turnover in healthy tissues and has a half-life of more than 70 years. Elastin is not only a structural protein, influencing the architecture and biomechanical properties of the extracellular matrix, but also plays a vital role in various physiological processes. Bioactive elastin peptides termed elastokines - in particular those of the GXXPG motif - occur as a result of proteolytic degradation of elastin and its non-cross-linked precursor tropoelastin and display several biological activities. For instance, they promote angiogenesis or stimulate cell adhesion, chemotaxis, proliferation, protease activation and apoptosis. Elastin-degrading enzymes such as matrix metalloproteinases, serine proteases and cysteine proteases slowly damage elastin over the lifetime of an organism. The destruction of elastin and the biological processes triggered by elastokines favor the development and progression of various pathological conditions including emphysema, chronic obstructive pulmonary disease, atherosclerosis, metabolic syndrome and cancer. This review gives an overview on types of human elastases and their action on human elastin, including the formation, structure and biological activities of elastokines and their role in common biological processes and severe pathological conditions.

Lysyl oxidase-like 2 (LOXL2)-mediated cross-linking of tropoelastin.

Lysyl oxidases (LOXs) play a central role in extracellular matrix remodeling during development and tumor growth and fibrosis through cross-linking of collagens and elastin. We have limited knowledge of the structure and substrate specificity of these secreted enzymes. LOXs share a conserved C-terminal catalytic domain but differ in their N-terminal region, which is composed of 4 repeats of scavenger receptor cysteine-rich (SRCR) domains in LOX-like (LOXL) 2. We investigated by X-ray scattering and electron microscopy the low-resolution structure of the full-length enzyme and the structure of a shorter form lacking the catalytic domain. Our data demonstrate that LOXL2 has a rod-like structure with a stalk composed of the SRCR domains and the catalytic domain at its tip. We detected direct interaction between LOXL2 and tropoelastin (TE) and also LOXL2-mediated deamination of TE. Using proteomics, we identified several allysines together with cross-linked TE peptides. The elastin-like material generated was resistant to trypsin proteolysis and displayed mechanical properties similar to mature elastin. Finally, we detected the codistribution of LOXL2 and elastin in the vascular wall. Altogether, these data suggest that LOXL2 could participate in elastogenesis in vivo and could be used as a means of cross-linking TE in vitro for biomimetic and cell-compatible tissue engineering purposes.-Schmelzer, C. E. H., Heinz, A., Troilo, H., Lockhart-Cairns, M.-P., Jowitt, T. A., Marchand, M. F., Bidault, L., Bignon, M., Hedtke, T., Barret, A., McConnell, J. C., Sherratt, M. J., Germain, S., Hulmes, D. J. S., Baldock, C., Muller, L. Lysyl oxidase-like 2 (LOXL2)-mediated cross-linking of tropoelastin.

Soluble matrix protein is a potent modulator of mesenchymal stem cell performance.

We challenge the conventional designation of structural matrix proteins primarily as supporting scaffolds for resident cells. The extracellular matrix protein tropoelastin is classically regarded as a structural component that confers mechanical strength and resilience to tissues subject to repetitive elastic deformation. Here we describe how tropoelastin inherently induces a range of biological responses, even in cells not typically associated with elastic tissues and in a manner unexpected of typical substrate-dependent matrix proteins. We show that tropoelastin alone drives mesenchymal stem cell (MSC) proliferation and phenotypic maintenance, akin to the synergistic effects of potent growth factors such as insulin-like growth factor 1 and basic fibroblast growth factor. In addition, tropoelastin functionally surpasses these growth factors, as well as fibronectin, in allowing substantial media serum reduction without loss of proliferative potential. We further demonstrate that tropoelastin elicits strong mitogenic and cell-attractive responses, both as an immobilized substrate and as a soluble additive, via direct interactions with cell surface integrins αvß3 and αvß5. This duality of action converges the long-held mechanistic dichotomy between adhesive matrix proteins and soluble growth factors and uncovers the powerful, untapped potential of tropoelastin for clinical MSC expansion and therapeutic MSC recruitment. We propose that the potent, growth factor-like mitogenic and motogenic abilities of tropoelastin are biologically rooted in the need for rapid stem cell homing and proliferation during early development and/or wound repair.

Exposure of tropoelastin to peroxynitrous acid gives high yields of nitrated tyrosine residues, di-tyrosine cross-links and altered protein structure and function.

Elastin is an abundant extracellular matrix protein in elastic tissues, including the lungs, skin and arteries, and comprises 30-57% of the aorta by dry mass. The monomeric precursor, tropoelastin (TE), undergoes complex processing during elastogenesis to form mature elastic fibres. Peroxynitrous acid (ONOOH), a potent oxidising and nitrating agent, is formed in vivo from superoxide and nitric oxide radicals. Considerable evidence supports ONOOH formation in the inflamed artery wall, and a role for this species in the development of human atherosclerotic lesions, with ONOOH-damaged extracellular matrix implicated in lesion rupture. We demonstrate that TE is highly sensitive to ONOOH, with this resulting in extensive dimerization, fragmentation and nitration of Tyr residues to give 3-nitrotyrosine (3-nitroTyr). This occurs with equimolar or greater levels of oxidant and increases in a dose-dependent manner. Quantification of Tyr loss and 3-nitroTyr formation indicates extensive Tyr modification with up to two modified Tyr per protein molecule, and up to 8% conversion of initial ONOOH to 3-nitroTyr. These effects were modulated by bicarbonate, an alternative target for ONOOH. Inter- and intra-protein di-tyrosine cross-links have been characterized by mass spectrometry. Examination of human atherosclerotic lesions shows colocalization of 3-nitroTyr with elastin epitopes, consistent with TE or elastin modification in vivo, and also an association of 3-nitroTyr containing proteins and elastin with lipid deposits. These data suggest that exposure of TE to ONOOH gives marked chemical and structural changes to TE and altered matrix assembly, and that such damage accumulates in human arterial tissue during the development of atherosclerosis.

Lactoferrin induces tropoelastin expression by activating the lipoprotein receptor-related protein 1-mediated phosphatidylinositol 3-kinase/Akt pathway in human dermal fibroblasts.

Dermal fibroblasts generate the extracellular matrix component elastin, which is synthesized as tropoelastin (TE) and play a critical role in maintaining skin elasticity. Lactoferrin (Lf), an 80-kDa iron-binding glycoprotein, has biological functions such as anti-bacterial, -inflammatory, and -cancer activities. We previously reported that bovine Lf increases TE mRNA expression in human dermal fibroblasts. However, it remains unclear how Lf up-regulates TE expression. Here, we investigated molecular mechanisms underlying this effect. Lf promoted the phosphorylation of Akt1 and extracellular signal-regulated protein kinase (ERK)1/2. As expected, the phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 and the MAPK inhibitor U0126 inhibited Lf-induced phosphorylation of Akt1 and ERK1/2, respectively. In contrast, LY294002, but not U0126, inhibited Lf-induced TE expression. Human dermal fibroblasts expressed lipoprotein receptor-related protein 1 (LRP-1) mRNA, and the LRP1 inhibitor receptor-associated protein attenuated Lf-induced increases in TE expression. Furthermore, siRNA-mediated knockdown of LRP-1 significantly suppressed Lf-increased TE expression and Lf-induced Akt1 phosphorylation. Iron-saturated Lf (holo-Lf) increased TE expression and promoted Akt1 phosphorylation, when compared to those parameters in cells treated with iron-free Lf (apo-Lf). Transforming growth factor (TGF)-ß1 also increased TE expression. LY294002 inhibited TGF-ß1-mediated TE upregulation, whereas TGF-ß1 activated Akt2, but not Akt1, phosphorylation. These results indicate that holo-Lf, but not apo-Lf, increases TE expression through LRP-1 in human dermal fibroblasts and suggest that holo-Lf and TGF-ß1 enhance TE expression by activating the PI3K/Akt1 and PI3K/Akt2 pathways, respectively.

Inhibition of Receptor-Interacting Protein Kinase 1 with Necrostatin-1s ameliorates disease progression in elastase-induced mouse abdominal aortic aneurysm model.

Abdominal aortic aneurysm (AAA) is a common aortic disease with a progressive nature. There is no approved pharmacological treatment to effectively slow aneurysm growth or prevent rupture. Necroptosis is a form of programmed necrosis that is regulated by receptor-interacting protein kinases (RIPs). We have recently demonstrated that the lack of RIP3 in mice prevented aneurysm formation. The goal of the current study is to test whether perturbing necroptosis affects progression of existing aneurysm using the RIP1 inhibitors Necrostatin-1 (Nec-1) and an optimized form of Nec-1, 7-Cl-O-Nec-1 (Nec-1s). Seven days after aneurysm induction by elastase perfusion, mice were randomly administered DMSO, Nec-1 (3.2 mg/kg/day) and Nec-1s (1.6 mg/kg/day) via intraperitoneal injection. Upon sacrifice on day 14 postaneurysm induction, the aortic expansion in the Nec-1s group (64.12 ± 4.80%) was significantly smaller than that of the DMSO group (172.80 ± 13.68%) (P < 0.05). The mean aortic diameter of Nec-1 treated mice appeared to be smaller (121.60 ± 10.40%) than the DMSO group, though the difference was not statistically significant (P = 0.1). Histologically, the aortic structure of Nec-1s-treated mice appeared normal, with continuous and organized elastin laminae and abundant αActin-expressing SMCs. Moreover, Nect-1s treatment diminished macrophage infiltration and MMP9 accumulation and increased aortic levels of tropoelastin and lysyl oxidase. Together, our data suggest that pharmacological inhibition of necroptosis with Nec-1s stabilizes pre-existing aneurysms by diminishing inflammation and promoting connective tissue repair.

Prevention of abdominal aortic aneurysm progression by oral administration of green tea polyphenol in a rat model.

OBJECTIVE: Inflammation-mediated elastin destruction in the aortic medial layer is related to progression of abdominal aortic aneurysm (AAA). Epigallocatechin-3-gallate (EGCG), a major component of green tea polyphenols, reportedly increases elastin synthesis in vitro and may possess anti-inflammatory effects. We used a rat model to investigate whether EGCG could prevent AAA progression. METHODS: AAA was induced with administration of intraluminal elastase and extraluminal CaCl2 in male rats. Rats were randomly divided into a control group (n = 30) and an EGCG group (n = 30). In the EGCG group, an EGCG solution (20 mg/d) was administered orally to each rat from 2 weeks before AAA induction and continued 4 weeks beyond induction. RESULTS: The abdominal aortic diameter was significantly smaller in the EGCG group than in the control group on day 28 (2.9 ± 0.2 vs 2.3 ± 0.1 mm; P < .0001). The medial layer wall thickness and elastin content were significantly greater in the EGCG group than in the control group on day 28 (68.4 ± 13.6 vs 46.7 ± 13.4 µm [P < .001] and 20.3 ± 4.6 vs 9.5 ± 3.6% [P < .0001], respectively). Gene expression levels of tropoelastin and lysyl oxidase were significantly higher in the EGCG group immediately before AAA induction, indicating promoted elastoregeneration by EGCG administration (tropoelastin: 0.59 ± 0.36 control vs 1.24 ± 0.36 EGCG [P < .05], lysyl oxidase: 0.77 ± 0.45 control vs 1.34 ± 0.4 EGCG [P < .05]) (fold increase). Gene expression levels of inflammatory cytokines, including tumor necrosis factor-α and interleukin-1ß, were significantly downregulated in the EGCG group (1.82 ± 0.71 vs 0.97 ± 0.59 [P < .05] and 3.91 ± 3.24 vs 0.89 ± 0.59 [P < .05], respectively). On day 7, gene expression levels and gelatinolytic activity of matrix metalloproteinase 9 were significantly lower in the EGCG group (1.41 ± 0.86 vs 0.51 ± 0.42 [P < .05] and 1.00 ± 0.17 vs 0.29 ± 0.12 [P < .0001], respectively), whereas gene expression levels of tissue inhibitors of metalloproteinase-1 were significantly higher in the EGCG group (0.96 ± 0.11 vs 1.14 ± 0.09; P < .05). CONCLUSIONS: EGCG attenuated AAA progression in a rat model by preserving the aortic thickness and elastin content of the medial layer through regeneration of elastin, as mediated by anti-inflammatory effects, and subsequent reduction of matrix metalloproteinase activity.

Single nucleotide polymorphisms and domain/splice variants modulate assembly and elastomeric properties of human elastin. Implications for tissue specificity and durability of elastic tissue.

Polymeric elastin provides the physiologically essential properties of extensibility and elastic recoil to large arteries, heart valves, lungs, skin and other tissues. Although the detailed relationship between sequence, structure and mechanical properties of elastin remains a matter of investigation, data from both the full-length monomer, tropoelastin, and smaller elastin-like polypeptides have demonstrated that variations in protein sequence can affect both polymeric assembly and tensile mechanical properties. Here we model known splice variants of human tropoelastin (hTE), assessing effects on shape, polymeric assembly and mechanical properties. Additionally we investigate effects of known single nucleotide polymorphisms in hTE, some of which have been associated with later-onset loss of structural integrity of elastic tissues and others predicted to affect material properties of elastin matrices on the basis of their location in evolutionarily conserved sites in amniote tropoelastins. Results of these studies show that such sequence variations can significantly alter both the assembly of tropoelastin monomers into a polymeric network and the tensile mechanical properties of that network. Such variations could provide a temporal- or tissue-specific means to customize material properties of elastic tissues to different functional requirements. Conversely, aberrant splicing inappropriate for a tissue or developmental stage or polymorphisms affecting polymeric assembly could compromise the functionality and durability of elastic tissues. To our knowledge, this is the first example of a study that assesses the consequences of known polymorphisms and domain/splice variants in tropoelastin on assembly and detailed elastomeric properties of polymeric elastin.

Molecular-level insights into aging processes of skin elastin.

Skin aging is characterized by different features including wrinkling, atrophy of the dermis and loss of elasticity associated with damage to the extracellular matrix protein elastin. The aim of this study was to investigate the aging process of skin elastin at the molecular level by evaluating the influence of intrinsic (chronological aging) and extrinsic factors (sun exposure) on the morphology and susceptibility of elastin towards enzymatic degradation. Elastin was isolated from biopsies derived from sun-protected or sun-exposed skin of differently aged individuals. The morphology of the elastin fibers was characterized by scanning electron microscopy. Mass spectrometric analysis and label-free quantification allowed identifying differences in the cleavage patterns of the elastin samples after enzymatic digestion. Principal component analysis and hierarchical cluster analysis were used to visualize differences between the samples and to determine the contribution of extrinsic and intrinsic aging to the proteolytic susceptibility of elastin. Moreover, the release of potentially bioactive peptides was studied. Skin aging is associated with the decomposition of elastin fibers, which is more pronounced in sun-exposed tissue. Marker peptides were identified, which showed an age-related increase or decrease in their abundances and provide insights into the progression of the aging process of elastin fibers. Strong age-related cleavage occurs in hydrophobic tropoelastin domains 18, 20, 24 and 26. Photoaging makes the N-terminal and central parts of the tropoelastin molecules more susceptible towards enzymatic cleavage and, hence, accelerates the age-related degradation of elastin.

ASSOSIATION ANALYSYS OF 11 POLYMORPHISMS OF SNPS WITH ENDOTHELIUM DEPENDENT VASODILATATION IN CHILDREN WITH DIABETES MELLITUS TYPE 1.

We have studied the association with the level of the endothelium dependent vasodilatation (EDVD) among 11 single nucleotide polymorphisms (SNPs) of 10 genes in 45 children suffering from diabetes mellitus type 1. Following polymorphisms have been studied: G894→T of the eNOS exon 7 and Т-786→С of the eNOS promotor, А1266→G of the Eln exon 16, Т-381→C of the NPPB promotor, І\D of the ACE, Arg60→His of the LMP2, Met235→Thr of the AGT, A1166→C of the ATR1, C-1562→T of the MMP9, C-1306→T of the MMP2, and С-8→G of the PSMA6. It was shown that children with genotypes G/T by eNOS (G894→T), G/G by Eln (А1266→G), C/C by NPPB (Т-381→C) and І/D by ACE genes have lower EDVD (Р<0,05) than patients with others allelic variants of these genes, and this does not depend on duration of the disease, level of glicated hemoglobin and initial diameter of a humeral (brachial) artery. The combination of the above-stated genotypes influences most significantly on EDVD decrease (r=0,61; Р<0,01), comparing to each genotype separately.

Background differences in baseline and stimulated MMP levels influence abdominal aortic aneurysm susceptibility.

OBJECTIVE: Evidence has demonstrated profound influence of genetic background on cardiovascular phenotypes. Murine models in Marfan syndrome (MFS) have shown that genetic background-related variations affect thoracic aortic aneurysm formation, rupture, and lifespan of mice. MFS mice with C57Bl/6 genetic background are less susceptible to aneurysm formation compared to the 129/SvEv genetic background. In this study, we hypothesize that susceptibility to abdominal aortic aneurysm (AAA) will be increased in 129/SvEv mice versus C57Bl/6 mice. We tested this hypothesis by assessing differences in aneurysm size, tissue properties, immune response, and MMP expression. METHODS: Mice of C57Bl/6 or 129/SvEv background underwent AAA induction by periaortic application of CaCl2. Baseline aortic diameters, tissue properties and MMP levels were measured. After aneurysm induction, diameters, MMP expression, and immune response (macrophage infiltration and bone marrow transplantation) were measured. RESULTS: Aneurysms were larger in 129/SvEv mice than C57Bl/6 mice (83.0% ± 13.6 increase compared to 57.8% ± 6.4). The aorta was stiffer in the 129/SvEv mice compared to C57Bl/6 mice (952.5 kPa ± 93.6 versus 621.4 kPa ± 84.2). Baseline MMP-2 and post-aneurysm MMP-2 and -9 levels were higher in 129/SvEv aortas compared to C57Bl/6 aortas. Elastic lamella disruption/fragmentation and macrophage infiltration were increased in 129/SvEv mice. Myelogenous cell reversal by bone marrow transplantation did not affect aneurysm size. CONCLUSIONS: These data demonstrate that 129/SvEv mice are more susceptible to AAA compared to C57Bl/6 mice. Intrinsic properties of the aorta between the two strains of mice, including baseline expression of MMP-2, influence susceptibility to AAA.

Multiple microneedling sessions for minimally invasive facial rejuvenation: an objective assessment.

BACKGROUND: Microneedling or percutaneous collagen induction is a new modality used for skin rejuvenation, tightening, and scar remodeling. It offers a simple and effective treatment for photoaged skin with minimal disruption of the epidermis, thus limiting adverse effects and minimizing downtime. OBJECTIVES: To evaluate the efficacy, coupled with quantitative assessment, of the histological changes in response to multiple sessions of skin microneedling in the treatment of aging skin. PATIENTS AND METHODS: Ten patients with Fitzpatrick skin type III and IV and Glogau class II to III wrinkles were subjected to six skin microneedling sessions at 2-week intervals. Standard photographs and skin biopsy specimens were obtained at baseline and at one and three months after the start of treatment. Histometry for epidermal thickness and quantitative evaluation of collagen types I, III, and VII, newly synthesized collagen, total elastin, and tropoelastin were performed for all skin biopsies. RESULTS: Skin microneedling produced noticeable clinical improvement of photoaged skin, with corresponding histological enhancement. Compared to the baseline, collagen types I, III, and VII, as well as newly synthesized collagen, together with tropoelastin showed a statistically significant increase (P < 0.05) in response to treatment, while the mean level of total elastin was significantly decreased (P < 0.05) after treatment. CONCLUSIONS: Skin microneedling is a promising minimally invasive treatment option with the advantage of increased collagen production. However, multiple sessions are usually needed to maintain the improvement achieved.

Curcumin enhances the production of major structural components of elastic fibers, elastin, and fibrillin-1, in normal human fibroblast cells.

Curcumin is the major component of the yellow extract derived from the rhizome of the Curcuma longa, which is also a main bioactive polyphenol and has been generally used as a spice, food additive, and herbal medicine. In this presented study, we found that curcumin can enhance the production of major structural components of elastic fibers, elastin, and fibrillin-1, in normal human fibroblast cells via increasing ELN and FBN1 promoters' activities. With 2 µM curcumin treatment, the enhanced tropoelastin and fibrillin-1 protein amounts in Detroit 551 cells were approximately 134 and 130% of control, respectively. Therefore, our results demonstrated that curcumin may be used as a functional compound and applied to drugs, foods, and cosmetics in the future.