Elastin Levels Research Articles

Abstract 657: Inhibition Of MMPs In Hypertensive Cerebropathy Protects Blood-Brain Barrier In Dahl-Salt Sensitive Rats

Hypertensive cerebropathy is a pathological condition associated with cerebral edema and breakdown of the blood-brain barrier (BBB). Previous studies have shown that increased activity of matrix metalloproteinases (MMPs) leads to alteration in the extracellular matrix (ECM) which is associated with impairment of the neurovasculature, resulting in destruction of the BBB. However, the molecular pathways leading to this condition remains obscure. In this study, we hypothesize that pharmacological inhibition of MMPs modulates BBB disruption by decreasing MMP activity and thus ameliorating hypertensive cerebropathy. Methods: We used Dahl-salt sensitive (Dahl-SS) and Lewis rats which were fed a high salt diet. The groups were 1) Dahl-SS, 2) Dahl-SS+GM6001 (non-specific MMP inhibitor), 3) Lewis, and 4) Lewis+GM6001. GM6001 was given at 0.5mg/mL by intra-peritoneal injection on alternate days for 3 weeks. Blood pressure was measured by tail-cuff. The brain tissues were analyzed for oxidative stress, matrix metalloproteinase-9 (MMP-9) activity and tight junction proteins by Western blot and Zymography. Immunohistochemistry was used to determine the collogen/elastion ratio. Results: Mean arterial blood pressure was 169.10 ± 0.57 mm Hg in hypertensive Dahl-SS rats compared to 134.12 ± 1.2 mm Hg in Dahl-SS+GM6001 rats. The mean arterial pressures in Lewis and Lewis+GM6001 groups were 96.66 ± 0.54 and 87.69 ± 2.9 mm Hg respectively. There was an up-regulation in p47 (oxidative stress) and nitrotyrosine protein expression but down-regulation in super oxide dismutase-1(SOD-1) and tight junction proteins levels (zonula-occluden-1 and occludin) in hypertensive Dahl-SS and Lewis rats compared to GM6001 treated rats. MMP-9 protein expression as well activity was increased in hypertensive Dahl-SS and Lewis rats compared to GM6001 treated rats. Brain section stained for collagen and elastin showed an increase in collagen level in hypertensive Dahl-SS and Lewis rats compared to GM6001 treated rats, whereas the elastin level decreased in hypertensive Dahl-SS and Lewis rats compared to GM6001 treated rats. Conclusion: Our results suggest that in hypertensive Dahl-SS rats, pharmacological inhibition of MMPs attenuates high blood pressure and prevents disruption of blood brain barrier.

O001 Regulation of tissue remodelling by Oncostatin M in mouse lung is IL-6- and SMAD3-independent

Introduction Remodeling of extracellular matrix (ECM) in lungs occurs with various chronic inflammatory conditions including idiopathic pulmonary fibrosis and allergic airway disease. Although TGFbeta/SMAD signaling and other molecules are recognized as important in controlling ECM deposition, the gp130 cytokine (or IL-6/LIF cytokine) family including Oncostatin M (OSM) and IL-6 have also been implicated. OSM is a potent regulator of ECM in Balb/C and C57Bl/6 mouse lungs. Since OSM markedly induces IL-6 in vivo, here we tested the requirement for IL-6 using IL-6-/- mice and, in parallel, effects in SMAD3-/- mice in this system. Methods We used Adenovirus vector encoding murine OSM (AdOSM), to over-express OSM (endotracheal administration) and examined accumulation of collagen in lung tissue by histology, mRNA levels, chemokine levels in lung lavage and recruitment of CD45 + collagen1 + fibrocytes using Flow cytometry of whole lung mononuclear cell populations, with an n = 5 for each treatment in the separate mouse lines. Results In wild type mice, using empty vector Addel70 as a control treatment, AdOSM markedly induced mRNA levels of collagen1A1, 1A2, elastin, fibronectin, MMP13, TIMP-1, and IL-6 at Days 5 and 7 while TIMP-3 was reduced. Activated STAT3 was evident at day 2 and 7 as assessed by Western blots of individual mouse lung homogenates and immuno-histochemistry of tissue sections. Analysis of tissue at Day 7 and 14 showed increased collagen (picrosirus red stain) in parenchyma as well as around smaller airways. Collagen accumulation was still evident in IL-6-/- as well as SMAD3-/- lungs. FACS analysis showed significant elevation of CD45 + coll1 + fibrocyte accumulation in lung at day 7, however the fibrocyte chemokine SDF-1 (CXCL12) expression was reduced at the RNA and protein level in lungs. Conclusion Over-expression of OSM induces ECM in lungs that did not require IL-6 ligand nor SMAD3 signaling systems. ECM deposition was associated with increased fibrocyte accumulation that appeared independent of the chemokine SDF-1. The results suggest unique activities of OSM in lung tissue remodeling and a potential role in inflammatory lung diseases. (Supported by the Canadian Institutes for Health Research).

Regulation of aortic extracellular matrix synthesis via noradrenergic system and angiotensin II in juvenile rats

Context: Extracellular matrix (ECM) synthesis regulation by sympathetic nervous system (SNS) or angiotensin II (ANG II) was widely reported, but interaction between the two systems on ECM synthesis needs further investigation.Objective: We tested implication of SNS and ANG II on ECM synthesis in juvenile rat aorta.Materials and methods: Sympathectomy with guanethidine (50 mg/kg, subcutaneous) and blockade of the ANG II AT1 receptors (AT1R) blocker with losartan (20 mg/kg/day in drinking water) were performed alone or in combination in rats. mRNA and protein synthesis of collagen and elastin were examined by Q-RT-PCR and immunoblotting.Results: Collagen type I and III mRNA were increased respectively by 62 and 43% after sympathectomy and decreased respectively by 31 and 60% after AT1R blockade. Combined treatment increased collagen type III by 36% but not collagen type I. The same tendency of collagen expression was observed at mRNA and protein levels after the three treatments. mRNA and protein level of elastin was decreased respectively by 63 and 39% and increased by 158 and 15% after losartan treatment. Combined treatment abrogates changes induced by single treatments.Discussion and conclusion: The two systems act as antagonists on ECM expression in the aorta and combined inhibition of the two systems prevents imbalance of mRNA and protein level of collagen I and elastin induced by single treatment. Combined inhibition of the two systems prevents deposit or excessive reduction of ECM and can more prevent cardiovascular disorders.

Development and evaluation of axially aligned nanofibres for blood vessel tissue engineering

Biodegradable polymers have been extensively used as scaffolds to regenerate lost tissues. The geometry of the three-dimensional (3D) scaffolds has an influence on the cellular behaviour. In this study, we have developed 3D-scaffolds of axially aligned nanofibres of poly(lactic acid) (PLA), poly(caprolactone) (PCL) and PLA:CL (50:50) with diameters in the range 100-400 nm, internal diameter 4 mm, length 4 cm and wall thickness 0.2 mm, by using a dynamic collector. PCL and PLA:CL nanofibres were significantly less hydrophobic than PLA nanofibres. The porosity of PCL (16.23 ± 9.88%) and PLA:CL nanofibres (14.77 ± 3.41%) were comparable, while PLA (6.57 ± 1.54%) nanofibres had lower porosity. The tensile strength and Young's modulus of PLA was significantly lower than PCL and PLA:CL nanofibres and the suture retention strengths of all three scaffolds were comparable. After 4 weeks, the molecular weight of PLA nanofibres was reduced by 53% compared to 44% and 41% for PCL and the PLA:CL nanofibres, respectively. However, the PLA:CL nanofibres maintained their structural integrity even after 28 days. Platelet adhesion studies showed that PCL nanofibres had least tendency to be thrombogenic, while PLA:CL blend nanofibres were highly thrombogenic. Further, in vitro responses such as cell adhesion, proliferation and gene expression of human umbilical vascular endothelial cells (HUVECs) were evaluated. After 6 days of culture, the surfaces of all the three scaffolds were completely covered with cells. Our results demonstrate that expression levels of elastin, angiopoietin, laminin-4α and -5α were upregulated in PCL and PLA:CL nanofibres without the addition of any exogenous factors.

Prenatal tracheal reconstruction with a hybrid amniotic mesenchymal stem cells–engineered construct derived from decellularized airway

PurposeThis study was aimed at examining an airway construct engineered from autologous amniotic mesenchymal stem cells (aMSCs) and a xenologous decellularized airway scaffold as a means for tracheal repair. MethodsFetal lambs (N = 13) with a tracheal defect were divided into 2 groups. One group (acellular, n = 6) was repaired with a decellularized leporine tracheal segment. The other group (engineered, n = 7) received an identical graft seeded with expanded/labeled autologous aMSCs. Newborns were euthanized for multiple analyses. ResultsEleven lambs survived to term, 10 of which could breathe at birth. Engineered grafts showed a significant increase in diameter in vivo (P = .04) unlike acellular grafts (P = .62), although variable stenosis was present in all implants. Engineered constructs exhibited full epithelialization, compared with none of the acellular grafts (P = .002). Engineered grafts had a significantly greater degree of increase in elastin levels after implantation than acellular implants (P = .04). No such differences were noted in collagen and glycosaminoglycan contents. Donor cells were detected in engineered grafts, which displayed a pseudostratified columnar epithelium. ConclusionsConstructs engineered from aMSCs and decellularized airway undergo enhanced remodeling and epithelialization in vivo when compared with equivalent acellular implants. Amniotic mesenchymal stem cell–engineered airways may become an alternative for perinatal airway repair.

Multiple minimally invasive Erbium: Yttrium Aluminum Garnet laser mini-peels for skin rejuvenation: an objective assessment

As the demand for minimally invasive rejuvenation is increasing, micropeel resurfacing using Erbium:Yttrium Aluminum Garnet (Er:YAG) laser 2940 nm has been reported for the treatment of photoaged skin without ablation of the epidermis. However, little is known about the efficacy and underlying histologic changes associated with this type of treatment. The aims of this study are to evaluate the clinical effect and objectively quantify the histological changes in response to multiple sessions of Er:YAG laser 2940 nm mini-peels. Six female volunteers of Fitzpatrick skin type III-IV and Glogau's class I-III wrinkles were subjected to six microresurfacing peels at 2-week intervals using Er:YAG 2940 nm laser at subablative fluences of 2-3 J/cm(2) to treat periorbital rhytides. Quantitative evaluation of collagen types I, III, and VII, newly synthesized collagen, total elastin, and tropoelastin was performed by histochemistry and immunohistochemistry coupled with computerized morphometric analysis at base line, end of treatment, and 3 months post-treatment. Compared to the base line, evaluation of volunteers revealed obvious clinical improvement in response to Er:YAG mini-peels. Collagen types I, III, and VII, as well as newly synthesized collagen, together with tropoelastin showed a statistically significant increase in response to treatment, while the mean level of total elastin was significantly decreased in response to treatment. However, this was followed by regression of improvement at 3 months post-treatment but was still better than baseline. This study revealed that multiple Er:YAG mini-peels is a promising treatment option for photoaging as it reverses the signs of photoaged skin with little downtime and side effects. However, to maintain the short-term improvement achieved after treatment, continued Er:YAG 2940 nm laser mini-peels is required.

Transdermal administration of lactoferrin with sophorolipid1This article is part of a Special Issue entitled Lactoferrin and has undergone the Journal's usual peer review process.

Lactoferrin (Lf), a multifunctional glycoprotein, is known to activate dermal fibroblasts. Enhancing percutaneous absorption without decreasing the activity of Lf is critical in making the dermal administration of Lf beneficial. Sophorolipid (SL), a glycolipid-type biosurfactant, is known to form assemblies that may elevate the efficiency of the transdermal delivery of active ingredients. Here, we investigated the role of SL in the transdermal absorption of bovine Lf (bLf) and the effect of SL on the bLf activity on dermal fibroblasts. Transdermal absorption of bLf through a model skin was enhanced by 1.3-fold to 1.7-fold when SL was added. The effects of SL on the bLf activities on dermal fibroblasts were examined by cell proliferation activities and by gene expression levels of elastic fiber components, collagen IV, and hyaluronan synthases, revealing that SL did not depress the effect of bLf to any extent. Instead, the tropoelastin gene expression was upregulated ∼60-fold by bLf alone, which was further increased to ∼160-fold by bLf and SL together, suggesting a significant synergism between bLf and SL. Protein levels of elastin, assessed by immunohistochemistry, correlated well with the results of gene expressions. These results indicate the feasibility of the transdermal administration of bLf with SL.

Abstract 233: Quantification of Histological and Biomechanical Properties of Tissue-Engineered Vascular Graft in Inferior Vena Cava

Background: We developed the first tissue engineered vascular graft (TEVG) for use in congenital heart surgery and confirmed its significant potential via an initial clinical trial (Shinoka et al., JTCVS 2005). The primary complication of TEVG at medium term was stenosis attributed to suboptimal neovessel remodeling, which necessitated an investigation of the mechanics and mechanobiology to predict diverse aspects of the neovessel formation. Here we present the novel tools to investigate the evolving biomechanical properties of TEVG in a mouse inferior vena cava (IVC) replacement model. Hypothesis: The biomechanical properties of a TEVG evolve nonlinearly in time from a construct-dominated stiffness to a neovessel dominated stiffness. Novel biaxial biomechanical tests are required to quantify such changes rigorously. Method: Thirty-six CB17 SCID/beige mice were implanted with TEVG (PGA + P[CL/LA]) as IVC interposition graft. Twelve tissue engineered neovessels were harvested at 2, 6, and 12 weeks after implantation. Neovessels were characterized biomechanically using a custom, computer-controlled biaxial testing device, and compared with native veins. Extracellular matrix (ECM) remodeling of the neovessel was characterized histologically, biochemically, and molecular biologically. Result: The biaxial data revealed an improved compliance of the neovessel over time. Similarly, the axial stretch response of the TEVG became more like the native vein at 12 weeks. This response was quantified as a ratio of neo-vessel to native vein and improved to reach 52% at 12 weeks from 11% at 2 weeks. Scaffold mass in vivo, estimated by remaining scaffold on histology, showed a significant decline at 6 and 12 weeks. Gene expression of both type I and III collagen peaked at 2 weeks, and total collagen mass quantified by a Sircol™ assay revealed that total collagen peaked at 2 weeks but decreased gradually to the level of native vein. Gene expression of both tropoelastin and fibrillin-1 peaked at 2 weeks, whereas elastin mass quantified by Fastin™ assay showed a delayed peak level of elastin at 6 weeks. Gene expression of MMP-2 and 9 peaked at 6 and 2 weeks, respectively, implicating robust ECM remodeling at early time points. Conclusion: Our novel histo-mechanical approach is the first to show that neovessel formation is a dynamic process characterized by progressive degradation of the scaffold and increased ECM remodeling, which yields biomechanical properties of the TEVG similar to native vessel within 12 weeks in vivo.

Aberrant keratinization of reticular oral lichen planus is related to elastolysis

Aberrant keratinization is common in oral lichen planus (OLP) on buccal mucosa. Because elastin is crucial for maintaining the nonkeratinized phenotype of oral mucosa, we examined whether inflammatory elastases and the accompanying elastolysis were related to this feature. Protein and mRNA levels of keratinization-associated keratins (K1/10), nonkeratinization-associated keratins (K4/13), elastin, neutrophil elastase, and macrophage metalloelastase (MMP-12) were compared between normal alveolar mucosa and reticular OLP from buccal mucosa. Normal alveolar mucosae were cultured ex vivo on an organ culture system with and without elastase treatment. After 14 days, the mucosae were examined for 4 keratin expressions. The expressions of K1/10 and elastases increased, whereas those of K4/13 and elastin decreased in OLP. The nonkeratinized mucosa in the organ culture began to express K1/10 when elastase degraded the inherent elastin. Our study demonstrated that elastolysis in reticular OLP may be related to its aberrant keratinization.

Time-Dependent Alterations in Rat Macrovessels with Type 1 Diabetes

Vascular complications are associated with the progressive severity of diabetes, resulting in significant morbidity and mortality. This study quantifies functional vascular parameters and macrovascular structure in a rat model of type 1 diabetes. While there was no difference in the systemic arterial elastance (Ea) with 50 days of diabetes, changes were noted in the aorta and femoral artery including increased tunica media extracellular matrix content, decreased width of both the media and individual smooth muscle cell layers, and increased incidence of damaged mitochondria. Extracellular matrix proteins and elastin levels were significantly greater in the aorta of diabetic animals. These differences correlated with diminished matrix metalloprotease activity in the aorta of the diabetic animals. In conclusion, diabetes significantly altered the structure and ultrastructure of the aorta and femoral artery before systemic changes in arterial elastance could be detected.

Inhibition of MicroRNA-29 Enhances Elastin Levels in Cells Haploinsufficient for Elastin and in Bioengineered Vessels—Brief Report

The goal of this study was to determine whether antagonizing microRNA (miR)-29 enhances elastin (ELN) levels in cells and tissues lacking ELN. miR-29 mimics reduced ELN levels in fibroblasts and smooth muscle cells, whereas miR-29 inhibition increased ELN levels. Antagonism of miR-29 also increased ELN levels in cells from patients haploinsufficient for ELN and in bioengineered human vessels. miR-29 antagonism may promote increased ELN levels during conditions of ELN deficiencies.

The Effect of Cigarette Smoke in Bleomicyn Induced Pulmonary Fibrosis in the Rat Model

The role of cigarette smoking in the development and outcome of pulmonary fibrosis is uncertain. In this study, we aimed to assess the effect of route of bleomycin exposure in the development of pulmonary fibrosis and the effects of cigarette smo- ke on bleomycin-induced lung fibrosis. We studied five groups of rats; 1-control group, 2-intratracheal bleomycin (IT), 3- int- ratracheal bleomycin plus cigarette smoke for 4 wk (IT-S), 4- inhaled bleomycin (IN), 5- inhaled bleomycin plus cigarette smo- ke for 4 wk (IN-S). According to Aschoft's criteria, fibrosis score was higher in IT and IT-S compared to control, IN and IN- S groups. There was no significant difference between IT and IT-S groups. Histopathological evaluation of the lungs of rats revealed that neutrophils, macrophages, plasma cells and lymphocytes in alveolar interstitial space were significantly higher in IT and IT-S compared to IN and IN-S (p< 0.001). IT and IT-S showed a severe collagen, laminin, elastin, fibronectin and proteoglican levels in alveolar, vascular, airway and interstitial space. IN and IN-S showed mild inflammation in lung. There were alveolitis, edema, peribronchial fibrosis, fibroblast proliferation and emphysematous lesions in all groups except for the control group. In this study, we showed that in the development of pulmonary fibrosis in rats, intratracheal administration of bleomycin is more effective than bleomycin inhalation and smoking has no additional effect on development of fibrosis.

Cigarette smoke inhibits lung fibroblast proliferation by translational mechanisms

Cigarette smoke is a major cause of chronic obstructive pulmonary disease (COPD) and emphysema. Although cigarette smoke represses cellular proliferation, the molecular mechanisms underlying this phenomenon are unknown. CCAAT/enhancer-binding proteins (C/EBPs) are key regulators of cell cycle progression, differentiation and pro-inflammatory gene expression, are regulated predominantly at the translational level and may be involved in the pathogenesis of COPD. The aim of this study was to assess the effect of cigarette smoke on proliferation and the expression and translational regulation of C/EBPα and C/EBPβ in nondiseased primary human lung fibroblasts. Fibroblasts were exposed to cigarette smoke-conditioned medium (10% and 20% for 24 h). Proliferation was determined by [(3)H]thymidine incorporation. Protein expression levels were determined by immunoblotting and translation was monitored using a translation control reporter system. Cigarette smoke significantly reduced fibroblast proliferation and significantly upregulated full-length C/EBPα and C/EBPβ proteins due to a shift in the translational control of CEBPA and CEBPB mRNAs. This shift involved the re-initiation of mRNA translation via the regulatory upstream open reading frame, which coincided with increased interleukin-8 release and a decrease in functional elastin level. These findings provide a novel mechanism to understanding the tissue remodelling observed in the lungs of COPD patients.

Matrix metalloproteinase-12 leads to elastin degradation in BALB/c mice with eosinophilic meningitis caused by Angiostrongylus cantonensis

The rat lugworm Angiostrongylus cantonensis can cause eosinophilic meningitis. The purpose of this study was to determine whether matrix metalloproteinase (MMP)-12 and its substrate elastin participate in this inflammatory response. We showed that the MMP-12/tissue inhibitor of metalloproteinase-1 ratio was significantly increased in the CSF of A. cantonensis-infected mice from day 10 p.i., and reached high levels on days 20 and 25 p.i. MMP-12 production was correlated with elastin degradation, eosinophil count, blood–CSF barrier permeability and pathological changes in the subarachnoid space. Also, MMP-12 might contribute to elastin degradation in the meningeal vessel of the subarachnoid space. Simultaneous administration of albendazole and doxycycline significantly reduced the levels of MMP-12, elastin and Evans blue in mice with meningitis. These results imply that MMP-12 contributes to the elastin degradation that occurs in angiostrongyliasis meningitis, and doxycycline can reverse related inflammatory events by inhibition of MMP-12.

Reduction of reactive oxygen species prevents hypoxia-induced CREB depletion in pulmonary artery smooth muscle cells.

Hypoxia-induced pulmonary arterial hypertension (PAH) is a deadly disease characterized by progressive remodeling and persistent vasoconstriction of the pulmonary arterial system. Remodeling of the pulmonary artery (PA) involves smooth muscle cell (SMC) proliferation, hypertrophy, migration, and elevated extracellular matrix (ECM) production elicited by mitogens and oxidants produced in response to hypoxic insult. We previously reported that the transcription factor cAMP response element binding protein (CREB) is depleted in medial PA SMCs in remodeled, hypertensive vessels in rats or calves exposed to chronic hypoxia. In culture, CREB loss can be induced in PA SMCs by exogenous oxidants or platelet-derived growth factor. Forced depletion of CREB with small interfering RNA (siRNA) in PA SMCs is sufficient to induce their proliferation, hypertrophy, migration, dedifferentiation, and ECM production. This suggests that oxidant and/or mitogen-induced loss of CREB in medial SMCs is, in part, responsible for PA thickening. Here, we tested whether oxidant scavengers could prevent the loss of CREB in PA SMCs and inhibit SMC proliferation, migration, and ECM production using in vitro and in vivo models. Exposure of PA SMCs to hypoxia induced hydrogen peroxide (H2O2) production and loss of CREB. Treatment of SMCs with exogenous H2O2 or a second oxidant, Sin-1, elicited CREB depletion under normoxic conditions. Exogenous H2O2 also induced SMC proliferation, migration, and increased elastin levels as did forced depletion of CREB. In vivo, hypoxia-induced thickening of the PA wall was suppressed by the superoxide dismutase mimetic, Tempol, which also prevented the loss of CREB in medial SMCs. Tempol also reduced hypoxia-induced SMC proliferation and elastin deposition in the PA. The data indicate that CREB levels in the arterial wall are regulated in part by oxidants produced in response to hypoxia and that CREB plays a crucial role in regulating SMC phenotype and PA remodeling.

Comparison of the Compression Anastomosis Ring (EndoCAR) With a Circular Stapled Anastomosis in a Porcine Model

The aim of this study was to compare characteristics of rectal compression and stapled anastomoses at multiple time points. A total of 50 domestic pigs underwent a rectal anastomosis with a compression device or a circular stapler. They were sacrificed at zero-time, 2 days, 1 week, 1 month, and 3 months. Burst and maximal tolerated pressure and sites of failure, internal diameters, and radiographic leak rates were assessed. Desmosine (elastin) levels were determined. There were no clinical or radiographic leaks. Overall, 10 out of 27 (37%) compression anastomoses burst at higher pressures than the 14 out of 24 (58%) stapled anastomoses. Mean circumference and anastomotic index were greater for the EndoCAR at 1 week and 3 months. Desmosine levels were similar. In the porcine model, compression rectal anastomoses with the EndoCAR had improved bursting pressures and internal circumference compared with circular stapled anastomoses.

Effects of the Nd:YAG 1320-nm laser on skin rejuvenation: Clinical and histological correlations

The neodymium:yttrium-aluminum-garnet (Nd:YAG) laser is a popular non-ablative treatment used for skin rejuvenation. The purpose of this prospective study was to evaluate the clinical effects, coupled with a quantitative assessment, of the histological changes in response to Nd:YAG 1320-nm laser treatment of periocular wrinkles. Six volunteers with Fitzpatrick skin types III and IV and Glogau class I–II wrinkles were subjected to 3 months of Nd:YAG 1320-nm treatment in the periocular area (six sessions at 2-week intervals). Volunteers were photographed, and skin biopsies were obtained at baseline as well as 3 and 6 months after the start of treatments. Quantitative evaluation of total elastin, newly synthesized tropoelastin, collagen types I, III and VII, and newly synthesized collagen was performed using a computerized morphometric analysis. A noticeable clinical and histological improvement was observed after Nd:YAG 1320-nm treatment. Collagen types I, III and VII, as well as newly synthesized collagen, together with tropoelastin showed a statistically significant increase in response to treatment, while the mean level of total elastin was significantly decreased after treatment. Our data suggest that Nd:YAG 1320 nm is an effective treatment for skin rejuvenation as it stimulates the repair processes, and reverses the clinical, as well as the histopathological, signs of skin aging.

Decreased aortic diameter and compliance precedes blood pressure increases in postnatal development of elastin-insufficient mice

Increased arterial stiffness and blood pressure are characteristic of humans and adult mice with reduced elastin levels caused by aging or genetic disease. Direct associations have been shown between increased arterial stiffness and hypertension in humans, but it is not known whether changes in mechanical properties or increased blood pressure occur first. Using genetically modified mice with elastin haploinsufficiency (Eln(+/-)), we investigated the temporal relationship between arterial mechanical properties and blood pressure throughout postnatal development. Our results show that some mechanical properties are maintained constant regardless of elastin amounts. The peak diameter compliance for both genotypes occurs near the physiologic pressure at each age, which acts to provide maximum pulse dampening. The stress-strain relationships are similar between genotypes and become nonlinear near the systolic pressure for each age, which serves to limit distension under high pressure. Our results also show that some mechanical properties are affected by reduced elastin levels and that these changes occur before measurable changes in blood pressure. Eln(+/-) mice have decreased aortic diameter and compliance in ex vivo tests that are significant by postnatal day 7 and increased blood pressure that is not significant until postnatal day 14. This temporal relationship suggests that targeting large arteries to increase diameter or compliance may be an effective treatment for human hypertension.

Pulmonary fibroblasts from COPD patients show an impaired response of elastin synthesis to TGF-β1

Insufficiency of tissue repair by pulmonary fibroblasts may contribute to the decrease in elastic fibres in chronic obstructive pulmonary disease (COPD). In this study, the repair function of COPD fibroblasts was assessed by examining the response to transforming growth factor (TGF)-β1. Primary pulmonary fibroblasts were cultured from lung tissue of COPD patients and smoking control subjects. Cellular proliferation was measured with Alamar Blue reduction method. Levels of tropoelastin mRNA and soluble elastin was measured using real-time RT-PCR and Fastin elastin assay respectively. The percentage of increase in proliferation and elastin production after TGF-β1 (1 ng/ml) treatment was calculated for fibroblasts from each subject. COPD fibroblasts showed slower proliferation than control fibroblasts, and a reduced response to TGF-β1 stimulation. The promotive effect of TGF-β1 on elastin synthesis in control fibroblasts was significantly diminished in fibroblasts from COPD patients. Our findings indicate that COPD lung fibroblasts have a significantly decreased response to TGF-β1 in terms of proliferation and elastin production.

Angiotensin Type 1 Receptor Blocker Reduces Intimal Neovascularization and Plaque Growth in Apolipoprotein E–Deficient Mice

The interactions between the renin-angiotensin system and neovascularization in atherosclerotic plaque development are unclear. We investigated the effects of angiotensin II type 1 receptor antagonism in the pathogenesis of atherosclerosis in apolipoprotein E-deficient (ApoE(-/-)) mice with a special focus on plaque neovascularization. ApoE(-/-) mice fed a high-fat diet were randomly assigned to 1 of 2 groups and administered vehicle or olmesartan for 12 weeks. Quantification of plaque areas at the aortic root and in the thoracic and abdominal aorta revealed that, in all 3 of the regions, olmesartan reduced intimal neovessel density and the mRNA levels of toll-like receptor (TLR) 2 and TLR4. Olmesartan increased the levels of collagen and elastin, reduced the level of macrophages in the aortic root, and reduced the mRNA and the activity of matrix metalloproteinase (MMP) 2 in aortic roots and thoracic aortas. Aortic ring assay revealed that olmesartan-treated ApoE(-/-) mice had a markedly lower angiogenic response than that of untreated ApoE(-/-) mice. Bone marrow-derived endothelial progenitor cell-like c-Kit(+) cells from olmesartan-treated ApoE(-/-) mice showed marked impairment of cellular functions and lower expression of TLR2/TLR4 and MMP-2 compared with those of untreated controls. MMP-2 deficiency reduced intimal neovessel density and atherosclerotic lesion formation. Olmesartan and small-interfering RNA targeting TLR2 reduced the levels of TLR2, and MMP-2 mRNA induced angiotensin II in cultured endothelial cells. Angiotensin II type 1 receptor antagonism appears to inhibit intimal neovascularization in ApoE(-/-) mice, partly by reducing TLR2/TLR4-mediated inflammatory action and MMP activation, thus decreasing atherosclerotic plaque growth and increasing plaque instability.