中性粒细胞弹力蛋白酶在肺组织损伤修复中的作用

中性粒细胞弹力蛋白酶是中性粒细胞溶酶体内多种蛋白酶中最主要的一种中性蛋白酶,能够水解支气管周围组织,损伤支气管纤毛及上皮细胞,降解弹力蛋白、破坏肺泡结构,在急性肺损伤、支气管扩张、肺气肿及肺纤维化形成过程中均起着重要作用。本文就中性粒细胞弹力蛋白酶在肺组织损伤修复中的作用和机制进行综述。     

Characterisation of elastin and collagen in aortic bioprostheses

Porcine aortic valves used as cardiac valve bioprostheses are well adapted to physiological functions in the short term, but they lack long-term durability. Several multi-step extractions have been performed to obtain a perfectly acellular matrix. A new physical methodology is proposed to evaluate the resulting fibrous protein damage after biochemical extraction (TRI-COL and SDS). Thermal analysis techniques are adapted to collagen and elastin characterisation in the solid state. The aortic tissue thermal transitions are determined by differential scanning calorimetry (DSC): elastin glass transition is observed around 200°C, and collagen denaturation is observed around 230°C. These parameters are characteristic of the elastin network arrangement and of collagen triple-helix stability. The technique of thermostimulated currents (TSC) is well suited to specify the chain dynamics of proteins. The lowtemperature relaxations observed in both collagen and elastin are associated with localised motions, whereas the high-temperature modes are attributed to more delocalised motions of the chains. Therefore TSC and DSC spectrometries allow physical parameters specific to collagen and elastin to be obtained and their interaction in aortic tissues to be determined. According to the significant evolution of these parameters on SDS samples, the destabilising effect of this detergent is highlighted.     

Elastic system fibers in rat incisor periodontal ligament - immunohistochemical study using sections of fresh-frozen un-demineralized tissues

The aim of this study was to examine the localization and distribution of the components of elastic system fibers in the periodontal ligament of continuously erupting rat incisors in an effort to understand the mechanism of the eruption of the tooth. Sections of fresh-frozen, un-demineralized incisors of the rat mandible were prepared for immunohistochemical localization of elastin, fibrillin-2 and microfibril-associated glycoprotein-1 (MAGP-1). The structure of the periodontal ligament was well preserved in sections of fresh-frozen tissues. At the basal region of the ligament, intense immunolabelling for fibrillin-2 and MAGP-1 was observed as dot-like structures (transversely sectioned fibers) mainly on the tooth side of the ligament close to the cementum. These dot-like structures gradually increased in number towards the incisal area and were distributed throughout the tooth side of the ligament. This pattern of distribution was the same as that of reported oxytalan fibers. Elastin-immunopositive fibers were also detected in the ligament, although the labelling was limited and distribution was sparse. In conclusion, both fibrillin-2 and MAGP-1 immunopositive fibers may serve as a scaffold for deposition of tropoelastin during elastogenesis in the periodontal ligament. They may also provide guidance for the migration of fibroblasts to the occlusive side, which generates contractile forces for the movement of the tooth for continuous eruption of incisors.     

Biochemical,morphological and immunological findings in a patient with a cutis laxa-associated inborn disorder (De Barsy syndrome)

Clinical symptoms of a male infant are described and compared with cases now classified as the De Barsy syndrome, a distinct disorder related to cutis laxa. Morphologically, clastic fibres in skin were frayed and reduced in number and density. The collagen fibril network was normal. Biochemical studies on collagen metabolism in a skin specimen and in cultured skin fibroblasts showed a normal amino acid content and a normal electrophoretic pattern of collagen constituents. The chemotactic migration of cultured fibroblasts was diminished when compared with fibroblasts from donors of different age groups. Immunological investigations revealed an impaired granulocyte function.Abbreviations PNC polymorphonuclear cells - RBC red blood cells     

Development of a Tissue‐Engineered Artificial Ligament: Reconstruction of Injured Rabbit Medial Collateral Ligament With Elastin‐Collagen and Ligament Cell Composite Artificial Ligament

Ligament reconstruction using a tissue‐engineered artificial ligament (TEAL) requires regeneration of the ligament‐bone junction such that fixation devices such as screws and end buttons do not have to be used. The objective of this study was to develop a TEAL consisting of elastin‐coated polydioxanone (PDS) sutures covered with elastin and collagen fibers preseeded with ligament cells. In a pilot study, a ring‐type PDS suture with a 2.5 mm (width) bone insertion was constructed with/without elastin coating (Ela‐coat and Non‐coat) and implanted into two bone tunnels, diameter 2.4 mm, in the rabbit tibia (6 cases each) to access the effect of elastin on the bond strength. PDS specimens taken together with the tibia at 6 weeks after implantation indicated growth of bone‐like hard tissues around bone tunnels accompanied with narrowing of the tunnels in the Ela‐coat group and not in the Non‐coat group. The drawout load of the Ela‐coat group was significantly higher (28.0 ± 15.1 N, n = 4) than that of the Non‐coat group (7.6 ± 4.6 N, n = 5). These data can improve the mechanical bulk property of TEAL through extracellular matrix formation. To achieve this TEAL model, 4.5 × 10⁶ ligament cells were seeded on elastin and collagen fibers (2.5 cm × 2.5 cm × 80 µm) prior to coil formation around the elastin‐coated PDS core sutures having ball‐shape ends with a diameter of 2.5 mm. Cell‐seeded and cell‐free TEALs were implanted across the femur and the tibia through bone tunnels with a diameter of 2.4 mm (6 cases each). There was no incidence of TEAL being pulled in 6 weeks. Regardless of the remarkable degradation of PDS observed in the cell‐seeded group, both the elastic modulus and breaking load of the cell‐seeded group (n = 3) were comparable to those of the sham‐operation group (n = 8) (elastic modulus: 15.4 ± 1.3 MPa and 18.5 ± 5.7 MPa; breaking load: 73.0 ± 23.4 N and 104.8 ± 21.8 N, respectively) and higher than those of the cell‐free group (n = 5) (elastic modulus: 5.7 ± 3.6 MPa; breaking load: 48.1 ± 11.3 N) accompanied with narrowed bone tunnels and cartilage matrix formation. These data suggest that elastin increased the bond strength of TEAL and bone. Furthermore, our newly developed TEAL from elastin, collagen, and ligament cells maintained the strength of the TEAL even if PDS was degraded.     

Design of Fibrin Matrix Composition to Enhance Endothelial Cell Growth and Extracellular Matrix Deposition for In Vitro Tissue Engineering

Tissue-engineered blood vessel substitutes should closely resemble native vessels in terms of structure, composition, mechanical properties, and function. Successful cardiovascular tissue engineering requires optimization of in vitro culture environment that would produce functional constructs. The extracellular matrix (ECM) protein elastin plays an essential role in the cardiovascular system to render elasticity to blood vessel wall, whereas collagen is responsible for providing mechanical strength. The objective of this study was to understand the significance of various ECM components on endothelial cell (EC) growth and tissue generation. We demonstrate that, even though fibrin is a good matrix for EC growth, fibronectin is the crucial component of the fibrin matrix that enhances EC adhesion, spreading, and proliferation. Vascular EC growth factor is known to influence in vitro growth of EC, but, so far, ECM deposition in in vitro culture has not been reported. In this study, it is shown that incorporation of a mixture of hypothalamus-derived angiogenic growth factors with fibrin matrix enhances synthesis and deposition of insoluble elastin and collagen in the matrix, within 10 days of in vitro culture. The results suggest that a carefully engineered fibrin composite matrix may support EC growth, survival, and remodeling of ECM in vitro and impart optimum properties to the construct for resisting the shear stress at the time of implantation.     

Contribution of extracellular matrix to the mechanical properties of the heart

Extracellular matrix (ECM) components play essential roles in development, remodeling, and signaling in the cardiovascular system. They are also important in determining the mechanics of blood vessels, valves, pericardium, and myocardium. The goal of this brief review is to summarize available information regarding the mechanical contributions of ECM in the myocardium. Fibrillar collagen, elastin, and proteoglycans all play crucial mechanical roles in many tissues in the body generally and in the cardiovascular system specifically. The myocardium contains all three components, but their mechanical contributions are relatively poorly understood. Most studies of ECM contributions to myocardial mechanics have focused on collagen, but quantitative prediction of mechanical properties of the myocardium, or changes in those properties with disease, from measured tissue structure is not yet possible. Circumstantial evidence suggests that the mechanics of cardiac elastin and proteoglycans merit further study. Work in other tissues used a combination of correlation, modification or digestion, and mathematical modeling to establish mechanical roles for specific ECM components; this work can provide guidance for new experiments and modeling studies in myocardium.     

Histologic and Ultrastructural Evaluation of Sutures Used for Surgical Fixation of the SMAS

In extensive SMAS face-lift surgery, retaining ligaments are released, and the SMAS is resutured to the deep fascia to maintain the advanced position. The suture used to reattach the SMAS should replicate the quality of support provided by the original ligaments. Nonabsorbable sutures (monofilament and braided) retrieved intraoperatively from 22 patients undergoing secondary face-lift procedures were examined by light microscopy and transmission electronmicroscopy. A distinctive enclosure of dense collagen and elastin formed around both types of suture. Based on the presence of inflammatory cells, fibroblasts, collagen, and elastin, the tissue reaction to monofilament suture was less than with the braided suture. The collagen and elastin were thicker around the braided suture, and, additionally the collagen matrix infiltrated between the individual filaments. Ultrastructural analysis of the braided suture showed significant collagen binding around each individual filament. The greater quantity of connective tissue around the thread which continued into the interstices of the braided suture has the characteristics of a ligament. This suggests a stronger and more lasting tissue fixation.     

Development of HLA-matched vascular grafts utilizing decellularized human umbilical artery

Worldwide, there is a great need of small diameter vascular grafts that can be used in human disorders such as cardiovascular and peripheral vascular disease. Until now, severe adverse reactions are caused from the use of synthetic or animal derived grafts, while the use of autologous vessels is restricted only in a small number of patients. The limited availability of the vessels might be resolved by the use of HLA-matched vascular grafts utilizing the decellularized human umbilical arteries. In this study, human umbilical arteries were decellularized and then repopulated with Mesenchymal Stem Cells. The HLA-genotype of the repopulated grafts, analyzed by Next Generation Sequencing technology, indicated their successful production. The HLA-matched vascular grafts could be generated efficiently and might be used in personalized medicine.