35 research outputs found
Hypoxyprobe™ reveals dynamic spatial and temporal changes in hypoxia in a mouse model of endometrial breakdown and repair
BACKGROUND: Menstruation is the culmination of a cascade of events, triggered by the withdrawal of progesterone at the end of the menstrual cycle. Initiation of tissue destruction and endometrial shedding causes spiral arteriole constriction in the functional layer of the endometrium. Upregulation of genes involved in angiogenesis and immune cell recruitment, two processes that are essential to successful repair and remodelling of the endometrium, both thought to be induced by reduced oxygen has been reported. Evidence for stabilisation/increased expression of the transcriptional regulator hypoxia inducible factor in the human endometrium at menses has been published. The current literature debates whether hypoxia plays an essential role during menstrual repair, therefore this study aims to delineate a role for hypoxia using a sensitive detection method (the Hypoxyprobe™) in combination with an established mouse model of endometrial breakdown and repair. RESULTS: Using our mouse model of menses, during which documented breakdown and synchronous repair occurs in a 24 h timeframe, in combination with the Hypoxyprobe™ detection system, oxygen tensions within the uterus were measured. Immunostaining revealed striking spatial and temporal fluctuations in hypoxia during breakdown and showed that the epithelium is also exposed to hypoxic conditions during the repair phase. Furthermore, time-dependent changes in tissue hypoxia correlated with the regulation of mRNAs encoding for the angiogenic genes vascular endothelial growth factor and stromal derived factor (Cxcl12). CONCLUSIONS: Our findings are consistent with a role for focal hypoxia during endometrial breakdown in regulating gene expression during menses. These data have implications for treatment of endometrial pathologies such as heavy menstrual bleeding
The Online Bingo Boom in the UK: A Qualitative Examination of Its Appeal
Online bingo has seen significant growth in recent years. This study sought to increase understanding of this growth by exploring the appeal of online bingo. Our aim was to examine the content of ten online bingo websites in the UK and analyse a qualitative secondary dataset of 12 female bingo players to investigate the appeal of online bingo. Using two distinct data sources allowed us to assess how the key messages online websites are trying to convey compare with actual players' motivation to play bingo. Our analysis of bingo websites found a common theme where websites were easy to navigate and structured to present a light-hearted, fun, reassuring, social image of gambling. In addition, the design decisions reflected in the bingo sites had the effect of positioning online bingo as a benign, child-like, homely, women-friendly, social activity. Comparison of the website content with our participants' reasons to play bingo showed congruence between the strategies used by the bingo websites and the motivations of bingo players themselves and the benefits which they seek; suggesting that bingo websites strive to replicate and update the sociability of traditional bingo halls. Online bingo differs from traditional forms of bingo in its ability to be played anywhere and at any time, and its capacity to offer a deeply immersive experience. The potential for this type of online immersion in gambling to lead to harm is only just being investigated and further research is required to understand how the industry is regulated, as well as the effects of online bingo on individual gambling ‘careers'
Regulation of endometrial regeneration; mechanisms contributing to repair and restoration of tissue integrity following menses
The human endometrium is a dynamic, multi-cellular tissue that lines the inside of the
uterine cavity. During a woman’s reproductive lifespan the endometrium is subjected to
cyclical episodes of proliferation, angiogenesis, differentiation/decidualisation, shedding
(menstruation), repair and regeneration in response to fluctuating levels of oestrogen and
progesterone secreted by the ovaries. The endometrium displays unparalleled, tightly
regulated, tissue remodelling resulting in a healed, scar-free tissue following menses or
parturition. Mechanisms responsible for initiation of menses have been well documented:
following progesterone withdrawal there is an increase in inflammatory mediators, focal
hypoxia and induction and activation of matrix-degrading enzymes. In contrast, the
molecular and cellular changes responsible for rapid, regulated, tissue repair at a time when
oestrogen and progesterone are low are poorly understood.
Histological studies using human menstrual phase endometrium have revealed that tissue
destruction and shedding occur in close proximity to re-epithelialisation/repair. It has been
proposed that re-epithelialisation involves proliferation of glandular epithelial cells in the
remaining basal compartment; there is also evidence for a contribution from the underlying
stroma. A role for androgens in the regulation of apoptosis of endometrial stromal cells has
been proposed but the impact of androgens on tissue repair has not been investigated. Studies
using human xenografts and primates have been used to model some aspects of the impact of
progesterone withdrawal but simultaneous shedding (menses) and repair have not been
modelled in mice; the species of choice for translational biomedical research.
In the course of the studies described in this thesis, the following aims have been addressed:
1. To establish a model of menses in the mouse which mimics menses in women,
namely; simultaneous breakdown and repair, overt menstruation, immune cell
influx, tissue necrosis and re-epithelialisation.
2. To use this model to determine if the stromal cell compartment contributes to
endometrial repair.
3. To examine the impact of androgens on the regulation of menses (shedding) and
repair.
An informative mouse model of endometrial breakdown that was characterised by overt
menses, as well as rapid repair, was developed. Immunohistological evidence for extensive
tissue remodelling including active angiogenesis, transient hypoxia, epithelial cell-specific
proliferation and re-epithelialisation were obtained by examining uterine tissues recovered
during an “early window of breakdown and repair” (4 to 24 hours after progesterone
withdrawal). Novel data included identification of stromal cells that expressed epithelial cell
markers, close to the luminal surface following endometrial shedding, suggesting a role for
mesenchymal to epithelial transition (MET) in re-epithelialisation of the endometrium. In
support of this idea, array and qRTPCR analyses revealed dynamic changes in expression of
mRNAs encoded by genes known to be involved in MET during the window of breakdown
and repair. Roles for hypoxia and tissue-resident macrophages in breakdown and tissue
remodelling were identified.
Treatment of mice with dihydrotestosterone to mimic concentrations of androgens circulated
in women at the time of menses had an impact on the timing and duration of endometrial
breakdown. Array analysis revealed altered expression of genes implicated in MET and
angiogenesis/inflammation highlighting a potential, previously unrecognised role for
androgens in regulation of tissue turnover during menstruation.
In summary, using a newly refined mouse model new insights were obtained, implicating
androgens and stromal MET in restoration of endometrial tissue homeostasis during
menstruation. These findings may inform development of new treatments for disorders
associated with aberrant repair such as heavy menstrual bleeding and endometriosis
Para-infectious brain injury in COVID-19 persists at follow-up despite attenuated cytokine and autoantibody responses
To understand neurological complications of COVID-19 better both acutely and for recovery, we measured markers of brain injury, inflammatory mediators, and autoantibodies in 203 hospitalised participants; 111 with acute sera (1–11 days post-admission) and 92 convalescent sera (56 with COVID-19-associated neurological diagnoses). Here we show that compared to 60 uninfected controls, tTau, GFAP, NfL, and UCH-L1 are increased with COVID-19 infection at acute timepoints and NfL and GFAP are significantly higher in participants with neurological complications. Inflammatory mediators (IL-6, IL-12p40, HGF, M-CSF, CCL2, and IL-1RA) are associated with both altered consciousness and markers of brain injury. Autoantibodies are more common in COVID-19 than controls and some (including against MYL7, UCH-L1, and GRIN3B) are more frequent with altered consciousness. Additionally, convalescent participants with neurological complications show elevated GFAP and NfL, unrelated to attenuated systemic inflammatory mediators and to autoantibody responses. Overall, neurological complications of COVID-19 are associated with evidence of neuroglial injury in both acute and late disease and these correlate with dysregulated innate and adaptive immune responses acutely
Identifying the role of androgens in endometrial function
The endometrium is a complex multicellular tissue that undergoes dynamic alterations under
the control of ovarian-derived sex steroid hormones. During the proliferative phase of the
human menstrual cycle, oestrogen induces proliferation of the endometrial epithelium while
during the progesterone-dominated secretory phase, the endometrial stromal compartment
differentiates in preparation for pregnancy. This differentiation event is termed decidualisation
and it is accompanied by immune cell infiltration, vascular remodelling and secretion of
cytokines and growth factors, as well as a newfound capacity of active steroid synthesis in the
endometrium. Defective decidualisation has been described in several endometrial-associated
disorders such as endometriosis, a pathology of ectopic endometrial tissue in the peritoneal
cavity, often associated with infertility. Rodent models have been used for the investigation of
endometrial physiology and pathology due to the similarity in uterine tissue architecture,
appropriate endometrial responses to steroid hormones and the opportunity to inform cellular
mechanisms using genetic manipulation.
While the impact of 17β-oestradiol and progesterone on endometrial function have been
extensively studied, androgens have only recently emerged as potent potential regulators of
the endometrium, however, their impact on cell function has not been fully elucidated.
The aims of this study were to:
Identify the impact of androgens on endometrial function using a mouse model of steroid
depletion (ovariectomy) followed by administration of the potent androgen
dihydrotestosterone (DHT).
Investigate the capacity of endometrial stromal cells to synthesise androgens during
decidualisation using human primary endometrial stromal cells (hESCs) decidualised in vitro.
Elucidate the decidualisation response of hESCs from women with endometriosis after
modulation of androgen receptor (AR) function during decidualisation.
Novel results obtained provided evidence of a role for androgens in inducing a trophic effect
in the mouse uterus characterised by: pronounced endometrial epithelial proliferation, altered
expression pattern of AR, changes in the expression of genes involved in cell-cycle
progression and stromal-epithelial cross-talk. In addition, androgen treatment resulted in a
striking and unexpected increase in the number of endometrial glands. Decidualisation of
hESCs resulted in time-dependent changes in expression of the androgen synthesising
enzymes AKR1C3 and 5α-reductase (accompanied by biosynthesis of both testosterone and
DHT in a dynamic time-dependent manner). Notably, blocking of AR action arising from local
androgen signalling during decidualisation of hESCs culminates in sub-optimal
decidualisation as detected by the expression of the classical decidualisation markers IGFBP1
and PRL.
Women with endometriosis are reported to exhibit defective decidualisation, which may be
accompanied with infertility. Treatment of hESCs from women with endometriosis with an
AR agonist (DHT) or antagonist (flutamide) during decidualisation resulted in striking
differences in decidualisation response as demonstrated in a case-study approach.
Taken together, these findings highlight novel roles of androgens in regulating endometrial
function by impacting on cell proliferation, gland formation and decidualisation. These
striking new findings have implications for endometrial disorders such as endometriosis.
Future studies will focus on the use of selective androgen receptor modulators, a novel class
of compounds, with tissue-selective actions and without the undesired side-effects of potent
androgens. The use of AR modulators would benefit from a personalised medicine approach,
instructed by patient profiling to direct therapeutic targeting of endometrial disorders