Mechanisms of actions and roles of 5α-reduced glucocorticoids during inflammation and wound repair

Topical inflammatory diseases are most commonly treated with glucocorticoids, such as hydrocortisone, which have debilitating side effects including a range of systemic metabolic side effects as well as local effects such as to thin the skin and delay wound healing. Safer anti-inflammatory therapies are required and this thesis investigates a novel drug called 5α-tetrahydrocorticosterone (5α-THB) as a safer topical anti-inflammatory treatment. The main foci of this thesis are to assess the effects of 5αTHB on wound repair, as well as to characterise its mechanisms of action. Defective angiogenesis accounts for impaired wound healing brought about by steroids in many cases. 5αTHB suppressed vessel growth in a mouse ex vivo model of angiogenesis, but was less potent in this action than hydrocortisone, suggesting a safer therapeutic profile. To understand the underlying mechanisms, the effect of 5αTHB on gene expression in the mouse aorta during angiogenesis was compared with that of dexamethasone (a selective GR agonist) and hydrocortisone. Whereas dexamethasone and hydrocortisone caused differential expression of genes involved in inflammatory signalling and extracellular matrix remodelling, 5αTHB did not and instead selectively regulated Pecam1, involved in vasculature remodelling. This suggested that 5αTHB suppresses angiogenesis through different mechanisms of action in comparison to dexamethasone, and thus may not act through GR. Supporting this, dexamethasone increased the abundance of GR responsive transcripts (Per1, Hsd11b1, Fkbp51) whereas 5αTHB only increased the abundance of Per1. Furthermore, whereas the GR antagonist RU486 attenuated dexamethasone-regulation of genes, it had no effect on gene regulation by 5αTHB. To assess GR-mediation of 5αTHB effects, model systems were used to investigate whether 5αTHB is able to bind GR, stimulate its nuclear translocation, and initiate changes in its interaction with co regulator peptides. In a competitive binding assay, dexamethasone and hydrocortisone both decreased the fluorescence polarisation of a GR specific ligand, consistent with GR binding. In contrast, 5αTHB only displaced the specific GR ligand at very high concentrations. In terms of nuclear translocation, 5αTHB also did not have an effect on the ratio of GR in the nucleus and cytoplasm (N/C) of A549 cells, suggesting that GR remained predominantly in the cytoplasm after 5αTHB treatment and did not translocate into the nucleus, whereas dexamethasone increased the N/C ratio at three different time points. Likewise, whereas dexamethasone stimulated changes in the interaction between GR and many co regulator peptides, 5αTHB had no effect. Collectively these results from model systems suggest that 5αTHB does not work through the conventional GR mechanism of action. Finally, a hypothesis generating approach was taken in order to gain hints into how 5αTHB may be working. A microarray was performed to compare the effects of 5αTHB and dexamethasone on gene expression in human peripheral blood derived macrophages. Both dexamethasone and 5αTHB were able to cause differential expression of genes in these cells. However unexpectedly, out of the 350 genes regulated by dexamethasone, and the 165 genes regulated by 5αTHB, only 35 genes were commonly regulated by both steroids. This suggested that 5αTHB mainly acts through different mechanisms to dexamethasone also in macrophages. In an enrichment analysis of the differentially expressed genes, whereas the NFκB signalling pathway was the top enriched pathway in genes only regulated by dexamethasone, enriched pathways in genes only regulated by 5αTHB included those related to phagocytosis, the TGF-beta signalling pathway, and Th1-Th2 cell differentiation. This thesis therefore provides evidence to suggest that 5αTHB may provide a safer topical anti-inflammatory steroid, less harmful to wound repair processes. In addition, the mechanisms underlying the action of 5αTHB differ from those of classical GCs, consistent with its reduced side-effect profile. Other potential mechanisms, such as actions through the mineralocorticoid receptor, must now be explored

Safer topical treatment for inflammation using 5α-tetrahydrocorticosterone in mouse models

Use of topical glucocorticoid for inflammatory skin conditions is limited by systemic and local side-effects. This investigation addressed the hypothesis that topical 5α-tetrahydrocorticosterone (5αTHB, a corticosterone metabolite) inhibits dermal inflammation without affecting processes responsible for skin thinning and impaired wound healing. The topical anti-inflammatory properties of 5αTHB were compared with those of corticosterone in C57Bl/6 male mice with irritant dermatitis induced by croton oil, whereas its effects on angiogenesis, inflammation, and collagen deposition were investigated by subcutaneous sponge implantation. 5αTHB decreased dermal swelling and total cell infiltration associated with dermatitis similarly to corticosterone after 24 h, although at a five fold higher dose, but in contrast did not have any effects after 6 h. Pre-treatment with the glucocorticoid receptor antagonist RU486 attenuated the effect of corticosterone on swelling at 24 h, but not that of 5αTHB. After 24 h 5αTHB reduced myeloperoxidase activity (representative of neutrophil infiltration) to a greater extent than corticosterone. At equipotent anti-inflammatory doses 5αTHB suppressed angiogenesis to a limited extent, unlike corticosterone which substantially decreased angiogenesis compared to vehicle. Furthermore, 5αTHB reduced only endothelial cell recruitment in sponges whereas corticosterone also inhibited smooth muscle cell recruitment and decreased transcripts of angiogenic and inflammatory genes. Strikingly, corticosterone, but not 5αTHB, reduced collagen deposition. However, both 5αTHB and corticosterone attenuated macrophage infiltration into sponges. In conclusion, 5αTHB displays the profile of a safer topical anti-inflammatory compound. With limited effects on angiogenesis and extracellular matrix, it is less likely to impair wound healing or cause skin thinning

Species-specific regulation of angiogenesis by glucocorticoids reveals contrasting effects on inflammatory and angiogenic pathways

<div><p>Glucocorticoids are potent inhibitors of angiogenesis in the rodent <i>in vivo</i> and <i>in vitro</i> but the mechanism by which this occurs has not been determined. Administration of glucocorticoids is used to treat a number of conditions in horses but the angiogenic response of equine vessels to glucocorticoids and, therefore, the potential role of glucocorticoids in pathogenesis and treatment of equine disease, is unknown. This study addressed the hypothesis that glucocorticoids would be angiostatic both in equine and murine blood vessels.The mouse aortic ring model of angiogenesis was adapted to assess the effects of cortisol in equine vessels. Vessel rings were cultured under basal conditions or exposed to: foetal bovine serum (FBS; 3%); cortisol (600 nM), cortisol (600nM) plus FBS (3%), cortisol (600nM) plus either the glucocorticoid receptor antagonist RU486 or the mineralocorticoid receptor antagonist spironolactone. In murine aortae cortisol inhibited and FBS stimulated new vessel growth. In contrast, in equine blood vessels FBS alone had no effect but cortisol alone, or in combination with FBS, dramatically increased new vessel growth compared with controls. This effect was blocked by glucocorticoid receptor antagonism but not by mineralocorticoid antagonism. The transcriptomes of murine and equine angiogenesis demonstrated cortisol-induced down-regulation of inflammatory pathways in both species but up-regulation of pro-angiogenic pathways selectively in the horse. Genes up-regulated in the horse and down-regulated in mice were associated with the extracellular matrix. These data call into question our understanding of glucocorticoids as angiostatic in every species and may be of clinical relevance in the horse.</p></div

'Because we can spend quality time together': Year 10 students' experiences and perceptions of 'family meals'

This paper reports the findings of a study investigating beliefs and practices surrounding the ‘family meal’. Using data from a sample of 415 Year 10 students, the paper challenges current media driven concerns about the loss of the ‘family meal’, instead finding that while, for some, it may look rather different from the traditional ideal, for a vast majority, meals are: eaten together, rather than in isolation; are home made, rather than store bought or fast food; and are the sites for conversation. While television watching is a common practice, it does not appear to preclude conversation. For these young people, opinion was equally divided on the value of the ‘family meal’, with those who saw it as important regarding its value as in the opportunity for family communication. The findings of the current study go some way to dispelling the myth that traditional notions of the family meal no longer exist. It also suggests that socialisation can still occur in non-traditional meal practices

The demise of the family meal? Evidence from the Antipodes

Popular discourse suggests that family meals are becoming increasingly rare and that their disappearance is contributing to the rising level of childhood obesity and to diminished family functioning, with negative psychosocial outcomes for children and adolescents. Evidence from research studies on the function of family mealtimes has failed to support such strong claims. What little is known about the social, cultural, nutritional and psychosocial impact of family meals is based on the mealtime practices of American families. This paper presents data from a survey of 625 adolescents drawn from schools in the metropolitan region of Perth, Western Australia . Using an online questionnaire, adolescents were asked about their current family meal practices and their ideas about family meals, as well as about their own activities, their health and wellbeing, and their sense of family connectedness. Relationships between various demographic factors, family and individual level variables, health indicators and eating practices are presented and issues regarding the methodology are described

Eating with your mouth shut: Family meals and etiquette

The table and the family meal as sites for the socialisation of children and adolescents are widely accepted. One of the ordinary manifestations of this socialisation is the reproduction of table manners or etiquette, which iterates and reiterates social ties and kinship, social roles and power relationships, especially for children. The table is the place children are taught the rules of the social community in which they live. Given that the family meal has morphed so that it no longer necessarily occurs with the constraint of the table, are rules about eating still observed? This study of 625 adolescents in Perth, Western Australia, illustrates that etiquette surrounding the family meal is, in fact, still evident. Many of the rules relating to bodily functions and movement around the table have deep historical ties; others, particularly those around where the meal should and should not be consumed, reflect the changing dynamics of family meal consumption. Whether or not adolescents conform to, or even acknowledge, the rules is partly due to the internalisation of behaviour codes so that they no longer seem like rules, and to the nature of adolescence itself as a time of questioning rules to establish autonomy and independence

Specimen of an intended travelling map of the roads of the State of South Carolina, from actual survey /

Shows householders' names.Alternate title at lower left: Road to Watboo Bridge, from Charleston, by Goose Creek Bridge & Strawberry Ferry.Hand col.Map in 3 strips and 6 sections.Orientation of sections varies.Wheat & Brun. Maps and Charts (1978 ed.) 597

Society, the person and the secular soul: A Durkheimian perspective

Orthodox readings of Durkheim’s work place great emphasis upon his hypotheses concerning society, social structure and social order. Here, discussion is generally based upon his presupposition of the primacy of some ‘thing’ names society over the discrete individual. This thesis, however, argues that within Durkheim’s fundamentally sociological framework of social realism there is no such ‘thing’ as the discrete, isolated individual or society. Instead, society and its constituting individuals are revealed as being involved in both a necessary and reciprocal relationship. It is through an examination of a relatively neglected aspect of Durkheim’s work, namely his constitution of the human person (as distinguished from the individual), that further insight into his perception of the relationship between a society and its constituting persons is gained. This requires the development of a deeper understanding of both Durkheim's idea that everything that is social consists in representations and his particular conception of the person as an individual plus a soul (itself a fragment of the collective soul). This, in turn, allows the development of three important arguments. First, Durkheim, as a resolutely sociological theorist of the person and of society, sees the relationship between society and the person as inherently reciprocal and in such a way that allows for the subjective and the objective world to be formed in relation to each other. Second, the particular vehicle for this person/society formation and mutual implication is the soul, which, for Durkheim, is a secular entity in the modem world. Third, as the need for order, harmony and social solidarity is generally considered a moral concern, Durkheim's conception of the person and the soul allows for the possibility of a morally autonomous individual existing within a moral, solidary society. That is, to be a moral, autonomous person is not to reject social solidarity. They are no longer contradictory or antagonistic states. The soul, as a complex element of both the individual person and of society, becomes the mechanism that facilitates the resolution of tensions in the individual/society relationship. Through the explication of these arguments, this thesis demonstrates that it is more appropriate to talk of the person (or the individual person) than of the individual per se. Furthermore, it is the notion of the person that should be borne in mind in any discussion of Durkheim's concern for society, social structure and social order. Society, by this reading, becomes a community of persons, rather than a society of discrete, atomistic, external individuals