Expression of Endo180 is spatially and temporally regulated during wound healing

AIMS

Interactions of cells with the extracellular matrix are important for normal wound healing and may play a role in scar formation. Remarkably, wound healing in human gingiva does not result in scar formation and serves as a model for wound regeneration. Endo180 (CD280) is a cell surface receptor that has novel functions to regulate cell migration and bind and internalize collagens that are key processes in wound healing. The aim of this study was to examine the expression of Endo180 during gingival wound regeneration.

METHODS AND RESULTS

Biopsies were collected from normal human gingiva and 1-60 days after wounding and expression of Endo180 was analysed by immunostaining. Expression of Endo180 by cultured fibroblasts and keratinocytes was studied by immunoblotting and semiquantitative reverse transcriptase-polymerase chain reaction. In normal gingiva, Endo180 was expressed by basal epithelial cells, fibroblasts, myofibroblasts, pericytes, macrophages and endothelial cells. In wounds, Endo180 expression was spatiotemporally increased in the migrating and differentiating wound epithelium, in subsets of myofibroblasts, pericytes, macrophages and endothelial cells. Growth factors involved in wound healing up-regulated the expression of Endo180 in keratinocytes and fibroblasts.

CONCLUSIONS

The findings suggest that Endo180 plays a role in re-epithelialization and connective tissue remodelling during wound regeneration.

B7-H1 expression is upregulated in peripheral blood CD14+ monocytes of patients with chronic hepatitis B virus infection, which correlates with higher serum IL-10 levels

Chronicity in hepatitis B virus (HBV) infection is maintained by increased type 2 T-helper cell response, possibly because of increased interleukin-10 (IL-10) productions. B7-H1 can negatively regulate T-cell responses via its receptor, programmed death 1. Ligation of B7-H1 to T-cells can result in the preferential secretion of IL-10. In this study, we investigated whether there was an upregulated expression of B7-H1 in peripheral blood mononuclear cells in patients chronically infected by HBV and further explored the correlation between B7-H1 expression and serum interleukin 2, interferon-gamma, IL-10, HBeAg, alanine aminotransferase (ALT) levels and viral load. Fifty-five patients with chronic HBV infection and 20 healthy controls (HCs) were enrolled in the present study. The results showed that in patients with chronic hepatitis B CD14+ monocytes but not CD3+ and CD19+ cells had a significantly increased expression of B7-H1 compared with HCs, which positively correlates with serum IL-10 levels and the presence of HBeAg and negatively correlates with serum ALT levels. In conclusion, chronic HBV patients harbour an increased B7-H1 expression in CD14+ monocytes compared with controls, which may be responsible for the increased serum IL-10 levels. This might be an important way by which HBV evades an adequate immune response, leading to viral persistence and disease chronicity.

Mycophenolic Acid Upregulates B7-DC Expression on Dendritic Cells, Which Is Associated With Impaired Allostimulatory Capacity of Dendritic Cells

In addition to its effects on lymphocytes, mycophenolic acid (MPA) may inhibit the allostimulatory capacity of dendritic cells (DC) via unknown mechanisms. B7-H1 and B7-DC surface markers on DC negatively regulate T-cell responses via the receptor PD-1. In this study, we sought to investigate whether B7-H1 and B7-DC are responsible for the inhibitory functions of MPA on DC. Mouse bone marrow-derived DC were cultured with recombinant granulocyte macrophage colony-stimulating factor (GM-CSF) and interleukin (IL)-4 in the presence or absence of MPA (0.01 micromol and 0.1 micromol). The DC phenotype was assessed by flow cytometry, their immunostimulatory capacity measured by mixed lymphocyte reaction (MLR), and cytokine production by ELISA. The results showed that MPA not only inhibited the expression of major histocompatibility complex (MHC) class II and costimulatory molecules CD80 and CD86 but upregulated B7-DC expression on mature DC induced by LPS. These findings were associated with a reduced allostimulatory ability and an altered cytokine secretion pattern of DC. Thus, we suggest that MPA upregulates B7-DC expression during DC maturation induced by LPS in vitro, an effect that may be responsible for MPA-mediated inhibitory effects on the allostimulatory capacity of DC.

New metabolically stabilized analogues of lysophosphatidic acid: agonists, antagonists and enzyme inhibitors

Lysophosphatidic acid (LPA) is a metabolically labile natural phospholipid with a bewildering array of physiological effects. We describe herein a variety of long-lived receptor-specific agonists and antagonists for LPA receptors. Several LPA and PA (phosphatidic acid) analogues also inhibit LPP (lipid phosphate phosphatase). The sn-1 or sn-2 hydroxy groups have been replaced by fluorine, difluoromethyl, difluoroethyl, O-methyl or O-hydroxyethoxy groups to give non-migrating LPA analogues that resist acyltransferases. Alkyl ether replacement of acyl esters produced lipase and acyltransferase-resistant analogues. Replacement of the bridging oxygen in the monophosphate by an alpha-monofluoromethylene-, alpha-bromomethylene- or alpha,alpha-difluoromethylenephosphonate gave phosphatase-resistant analogues. Phosphorothioate analogues with O-acyl and O-alkyl chains are potent, long-lived agonists for LPA1 and LPA3 receptors. Most recently, we have (i) prepared stabilized O-alkyl analogues of lysobisphosphatidic acid, (ii) explored the structure-activity relationship of stabilized cyclic LPA analogues and (iii) synthesized neutral head group trifluoromethylsulphonamide analogues of LPA. Through collaborative studies, we have collected data for these stabilized analogues as selective LPA receptor (ant)agonists, LPP inhibitors, TREK (transmembrane calcium channel) K+ channel agonists, activators of the nuclear transcription factor PPAR-gamma (peroxisome-proliferator-activated receptor-gamma), promoters of cell motility and survival, and radioprotectants for human B-cells.

Influence of baseline deformity definition on subsequent vertebral fracture risk in postmenopausal women

INTRODUCTION

Approaches for recognizing vertebral fractures remain controversial.

METHODS

An age-stratified population sample of 512 postmenopausal women was followed with serial radiographs for up to 12 years (4455 person-years).

RESULTS

112 women experienced a new vertebral fracture (20% reduction in any vertebral height from baseline) within this study period, for an annual age-adjusted (to US white women > or =50 years of age in 2000) incidence of 23 per 1000. Depending on the morphometric definition used, the prevalence of vertebral deformities at baseline ranged from 3 to 90%. A recent method to standardize vertebral heights produced the best agreement with a qualitative clinical reading of the films [kappa (kappa), 0.53]. Almost all of the different baseline definitions predicted future vertebral fractures, but most of the predictive power was attributable to the severe (e.g., 4 SD) deformities included within more generous (e.g., 3 SD) classifications. Whereas the generous definitions were more sensitive, and the restrictive ones more specific, their overall abilities to predict a new vertebral fracture were roughly comparable as evaluated by the c-index (analogous to the area under an ROC curve).

CONCLUSION

This result suggests that the choice of a morphometry definition depends on the particular application and, in particular, on whether it is more important to maximize sensitivity or specificity.

An expressed sequence tag SSR map of tetraploid alfalfa (Medicago sativa L.)

A genetic map constructed from a population segregating for a trait of interest is required for QTL identification. The goal of this study was to construct a molecular map of tetraploid alfalfa (Medicago sativa.) using simple sequence repeat (SSR) markers derived primarily from expressed sequence tags (ESTs) and bacterial artificial chromosome (BAC) inserts of M. truncatula. This map will be used for the identification of drought tolerance QTL in alfalfa. Two first generation backcross populations were constructed from a cross between a water-use efficient, M. sativa subsp. falcata genotype and a low water-use efficient M. sativa subsp. sativa genotype. The two parents and their F(1) were screened with 1,680 primer pairs designed to amplify SSRs, and 605 single dose alleles (SDAs) were amplified. In the F(1), 351 SDAs from 256 loci were mapped to 41 linkage groups. SDAs not inherited by the F(1), but transmitted through the recurrent parents and segregating in the backcross populations, were mapped to 43 linkage groups, and 44 of these loci were incorporated into the composite maps. Homologous linkage groups were joined to form eight composite linkage groups representing the eight chromosomes of M. sativa. The composite maps consist of eight composite linkage groups with 243 SDAs from M. truncatula EST sequences, 38 SDAs from M. truncatula BAC clone sequences, and five SDAs from alfalfa genomic SSRs. The total composite map length is 624 cM, with average marker density per composite linkage group ranging from 1.5 to 4.4 cM, and an overall average density of 2.2 cM. Segregation distortion was 10%, and distorted loci tended to cluster on individual homologues of several linkage groups.

Assessment of PCBs and PCDD/Fs along the Chinese Bohai Sea coastline using mollusks as bioindicators

Mollusk samples such as bivalves and gastropods were collected from eight sampling sites along Bohai Sea coastline from northeastern China. The samples were analyzed for polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs) by high-resolution gas chromatography/high-resolution mass spectrometry (HRGC-HRMS) to elucidate bioaccumulation of persistent organic pollutants in benthon. Residue levels of sigmaPCBs and sigmaPCDD/Fs were in the ranges of 66.1 to 583.6 ng/g and 0.9 to 15317 pg/g on a lipid-weight basis, respectively, The pollution source was identified using principal component analysis (PCA) in some coastal areas. It indicated that the typical pollution sources were characterized by PCB3, which was one Chinese technical product of PCBs. PCA also revealed the similarity patterns of PCBs between identical species collected from the different sites. The higher gastropod PCB concentrations were related to a former capacitor factory and the paint factories in some coastal areas, but this was not the case with the bivalves. The results of this study suggest that some gastropod species may be a potential bioindicator or "sentinel" organism for marine PCBs monitoring.

Modulation of insulin signalling by insulin sensitizers

Insulin resistance is a hallmark of Type II diabetes. It is well documented that insulin sensitizers such as peroxisome-proliferator-activated receptor gamma agonists and aspirin improve insulin action in vivo. The detailed mechanisms by which the insulin sensitizers promote insulin signalling, however, are not completely understood and remain somewhat controversial. In the present review, we summarize our studies attempting to explore the molecular mechanisms underlying the effects of insulin sensitizers in cells and in animal models of insulin resistance. In 3T3-L1 adipocytes and/or in HEK-293 cells stably expressing recombinant IRS1 protein (insulin receptor substrate protein 1), the peroxisome-proliferator-activated receptor gamma agonist rosiglitazone and aspirin promote insulin signalling by decreasing inhibitory IRS1 serine phosphorylation. Increased IRS1 Ser-307 phosphorylation and concomitant decreased insulin signalling as measured by insulin-stimulated IRS1 tyrosine phosphorylation and Akt threonine phosphorylation were observed in adipose tissues of Zucker obese rats compared with lean control rats. Treatment with rosiglitazone for 24 and 48 h increased insulin signalling and decreased IRS1 Ser-307 phosphorylation concomitantly. Treatment of the Zucker obese rats with rosiglitazone for 24 h also reversed the high circulating levels of free fatty acids, which have been shown to correlate with increased IRS1 serine phosphorylation. Taken together, the results suggest that IRS1 inhibitory serine phosphorylation is a key component of insulin resistance and its reversal may be physiologically relevant to insulin sensitization in vivo.

Identification of vertebral fractures: an update

Osteoporotic vertebral fracture is associated with increased morbidity and mortality. As a powerful predictor of future fracture risk, the identification of vertebral fracture helps target individuals who will benefit from anti-fracture therapy. The identification of vertebral fractures is problematic because (1) "normal" radiological appearances in the spine vary greatly both among and within individuals; (2) "normal" vertebrae may exhibit misleading radiological appearances due to radiographic projection error; and (3) "abnormal" appearances due to non-fracture deformities and normal variants are common, but can be difficult to differentiate from true vertebral fracture. Various methods of vertebral fracture definition have been proposed, but there is no agreed gold standard. Quantitative methods of vertebral fracture definition are objective and reproducible, but the major limitation of these methods is their inability to differentiate between vertebral deformity and vertebral fracture. The qualitative visual approach draws on the expertise of the reader, but it is a subjective method with poor interobserver agreement. Semiquantitative assessment of vertebral fracture is a standardized visual method, which is commonly applied in research studies as a surrogate gold standard. This method is more objective and reproducible than a purely qualitative approach, but can be difficult to apply. The established methods focus primarily on the identification of "reduced" or short vertebral height as an indication of vertebral fracture, but this is also a feature of some non-fracture deformities and normal variants. A modified visual approach known as algorithm-based qualitative assessment of vertebral fracture (ABQ) has recently been introduced, and this focuses on radiological evidence of change at the vertebral endplate as the primary indicator of fracture. Preliminary testing of the ABQ method has produced promising results, but the method requires further evaluation. Vertebral imaging by means of dual energy X-ray absorptiometry (DXA) scanner produces images of near-radiographic quality at a fraction of the radiation dose incurred by conventional radiography. There is growing interest in vertebral fracture assessment using this technique as a means of assessing a patient's fracture risk. Given the increasing availability of new technology and the importance of accurate diagnosis of vertebral fracture, there is an urgent need for better awareness of and training in the definition of vertebral fracture. Methods of vertebral fracture definition should be validated by testing the association with clinical outcomes of vertebral fracture, in particular the prediction of incident fractures.

Preparation of poly(ε-caprolactone)/continuous bioglass fibre composite using monomer transfer moulding for bone implant

Poly(epsilon-caprolactone) (PCL)/continuous bioglass fibre composite was prepared using the monomer transfer moulding technique coupled with a surface initiated polymerisation. The bioglass fibres were surface treated with an amine ended silane in order to initiate polymerisation of epsilon-caprolactone from the fibre surface. Surface initiated polymerisation significantly improved the Young's modulus and flexural strength and water resistance of the composite. Initial in vitro biocompatibility assessment suggests that amine ended silane treatment of bioglass fibres before their inclusion in the composite does not have a negative effect on the biological responses in terms of macrophage activation as measured by IL-1beta release and craniofacial osteoblast attachment.

Accuracy of height loss during prospective monitoring for detection of incident vertebral fractures

Vertebral fractures are the most common type of osteoporotic fracture, but more than two-thirds remain undetected. We have examined the relationship between height loss and the development of new vertebral fractures to determine whether there is a height loss threshold that has useful clinical accuracy to detect new fractures. We studied 985 postmenopausal women with osteoporosis in the placebo arms of the Vertebral Efficacy with Risedronate Therapy studies. Height was measured annually for 3 years using a wall-mounted stadiometer. New fractures were determined using quantitative and semi-quantitative radiographic morphometry. The relationship between height loss over three years and the number of new vertebral fractures was: height loss (cm) = 0.95 x number of new vertebral fractures-0.4 cm (r = 0.33). The odds ratio for the development of a new fracture increased up to 20.6 (95% confidence interval, 9.3, 45.8) when height loss was greater than 4.0 cm. At a threshold of > 2.0 cm height loss over 3 years, sensitivity was 35.5% for detecting new vertebral fractures and specificity was 93.6%. These findings show that there is a strong relationship between the amount of height loss and the risk of a new vertebral fracture. While there is no cut-off that can reliably rule in a new fracture, height loss of < or = 2.0 cm over 1-3 years has acceptable accuracy for ruling out an incident fracture.

Molecular cloning, localization and circadian expression of chicken melanopsin (Opn4): differential regulation of expression in pineal and retinal cell types

The avian retina and pineal gland contain autonomous circadian oscillators and photo-entrainment pathways, but the photopigment(s) that mediate entrainment have not been definitively identified. Melanopsin (Opn4) is a novel opsin involved in entrainment of circadian rhythms in mammals. Here, we report the cDNA cloning of chicken melanopsin and show its expression in retina, brain and pineal gland. Like the melanopsins identified in amphibians and mammals, chicken melanopsin is more similar to the invertebrate retinaldehyde-based photopigments than the retinaldehyde-based photopigments typically found in vertebrates. In retina, melanopsin mRNA is expressed in cells of all retinal layers. In pineal gland, expression was strong throughout the parenchyma of the gland. In brain, expression was observed in a few discrete nuclei, including the lateral septal area and medial preoptic nucleus. The retina and pineal gland showed distinct diurnal expression patterns. In pineal gland, melanopsin mRNA levels were highest at night at Zeitgeber time (ZT) 16. In contrast, transcript levels in the whole retina reached their highest levels in the early morning (ZT 0-4). Further analysis of melanopsin mRNA expression in retinal layers isolated by laser capture microdissection revealed different patterns in different layers. There was diurnal expression in all retinal layers except the ganglion cell layer, where heavy expression was localized to a small number of cells. Expression of melanopsin mRNA peaked during the daytime in the retinal pigment epithelium and inner nuclear layer but, like in the pineal, at night in the photoreceptors. Localization and regulation of melanopsin mRNA in the retina and pineal gland is consistent with the hypothesis that this novel photopigment plays a role in photic regulation of circadian function in these tissues.

Comparison of methods for the visual identification of prevalent vertebral fracture in osteoporosis

The identification of vertebral fracture in osteoporosis is based mainly on the identification of abnormal variation in vertebral shape, but this can be misleading in the presence of a non-fracture deformity or normal variant of vertebral shape. Qualitative identification of vertebral fracture (Qual) is influenced by the subjectivity of the approach, and although more objective, the semiquantitative method (SQ) can be difficult to apply. In addition, there has been little independent evaluation of SQ in relation to other approaches. We aimed to evaluate a new algorithm-based approach for the qualitative identification of vertebral fracture (ABQ) and to compare it with SQ and Qual. Two radiologists reported spinal radiographs for 372 postmenopausal women using Qual (reader 1), and SQ and ABQ (reader 2). Non-fracture deformities and normal variants were also reported using Qual and ABQ. The prevalence of vertebral fracture by subjects was higher for SQ (24%) than for Qual (11%) and ABQ (7%). Agreement was poor between SQ and the other methods, and moderate between Qual and ABQ. Twenty-two women with vertebral fracture were agreed by all three methods, similar to the total identified by ABQ (25 women). Seventeen women diagnosed with fracture by Qual, had non-fracture deformity or normal variant (but no fracture) according to ABQ. Of the women with SQ fractures, 53% and 70% were identified negative for fracture but positive for non-fracture deformity or normal variant by ABQ and Qual. The main sources of discrepancy between SQ and the other methods were Scheuermann's disease, normal variation, and degenerative change accompanied by short anterior vertebral height. For all methods, bone mineral density (BMD) and BMD Z-scores were lower in women with vertebral fractures than in those with no fractures. Bone mineral density and BMD Z-scores were also lower at the lumbar spine and total body in women with vertebral fractures according to Qual and ABQ than they were for SQ, and were lower in women with SQ fractures agreed by Qual and ABQ, compared with those diagnosed negative for fracture by Qual and ABQ (p<0.01). We conclude that poor agreement between methods arises mainly from difficulties in differentiating true fracture from non-fracture deformity. Our new approach attempts to address this problem but requires further testing in a larger study population.