Hospital Careful Hand Feeding Program Reduced Feeding Tube Use in Patients with Advanced Dementia.

OBJECTIVES: Tube feeding is prevalent among patients with advanced dementia despite empirical data that suggest its lack of benefit. To provide an alternative to tube feeding for end-of-life patients, a careful hand feeding program was launched in a Hong Kong geriatric convalescent hospital in February 2017. We aim to compare the rates of feeding tube insertion before and after program implementation and determine risk factors for feeding tube insertion. For patients on careful hand feeding, we evaluated their sustainability on oral feeding and the rates of hospital readmissions compared with tube feeding patients over the next 12 months. DESIGN: Retrospective cohort study. SETTING AND PARTICIPANTS: Advanced dementia patients ≥60 years with indication for tube feeding due to feeding problems admitted from January 2015-June 2019. METHODS: Data was collected on demographic and clinical variables, initial feeding mode (careful hand feeding vs. tube feeding), subsequent feeding mode changes, and hospital admissions over the next 12 months. Rates of feeding tube insertion, sustainability on oral feeding, and hospital readmissions were compared using Chi-square test. Risk factors for feeding tube insertion were assessed using logistic regression models. RESULTS: Among 616 advanced dementia patients admitted with feeding problems, feeding tube insertion rate declined significantly after careful hand feeding program implementation (72% vs 51% p<.001). Independent risk factors for feeding tube insertion were admission prior to program implementation, presence of dysphagia alone, dysphagia combined with poor intake, and lack of advance care planning. Among patients on careful hand feeding, 91% were sustained on oral feeding over the next twelve months and did not differ significantly before or after careful hand feeding program implementation (p=.67). There was no significant difference in hospital readmission rates between careful hand feeding patients and tube feeding patients before (83% vs 86%, p=.55) and after careful hand feeding program implementation (87% vs 85%, p=.63). CONCLUSIONS AND IMPLICATIONS: A hospital careful hand feeding program significantly reduced the feeding tube insertion rate among advanced dementia patients with feeding problems. The vast majority of patients on careful hand feeding were sustained on oral feeding over the next 12 months but their rate of hospital readmissions remained similarly high after program implementation.

Effectiveness of Partially Hydrolyzed Guar Gum in Reducing Constipation in Long Term Care Facility Residents: A Randomized Single-Blinded Placebo-Controlled Trial.

OBJECTIVES: To assess the effectiveness of partially hydrolyzed guar gum (PHGG) in improving constipation and reducing the use of laxatives among long term care facility (LTCF) residents. DESIGN: A single-center, prospective, randomized, placebo-controlled, single-blinded parallel-group trial from September 2021 to November 2021. SETTING: Four LTCF in Hong Kong. PARTICIPANTS: Fifty-two LTCF residents with chronic constipation (mean age: 83.9±7.6 years, male 38%). INTERVENTION: 5g PHGG mixed with 200ml water per day for 4 weeks was given to intervention group participants. Control group received 200ml water for 4 weeks. Participants continued their usual as-needed laxative (lactulose, senna or dulcolax) on their own initiative. MEASUREMENTS: Baseline measurements included age, gender, Charlson comorbidity index, Roackwood's Clinical Frailty Scale, body mass index and daily dietary fiber intake. Outcome measures were fecal characteristics assessed by Bristol Stool Form Scale, bowel opening frequency and laxative use frequency at baseline, first, second, third and fourth week of trial. Adverse events were measured. The study was registered on ClinicalTrial.gov; identifier: NCT05037565. RESULTS: There was no significant difference in bowel frequency and stool characteristics between the treatment group and control group. However, there was a significantly lower frequency of lactulose, senna, and total laxative use in the treatment group compared with controls in the third and fourth week. There was no significant difference in adverse effects between the two groups. CONCLUSION: This study showed that daily dietary fibre supplementation by using PHGG for 4 weeks in LTCF residents results in significantly less laxative use than placebo. It may be an effective way to reduce laxative dependence among older people living in LTCFs.

A spatial causal network approach for multi-stressor risk analysis and mapping for environmental impact assessments.

Environmental impact assessment (EIA) relies on rigorous scientific assessment of all potential causal pathways by which large-scale developments may impact on valued assets in a region. Despite their importance to informed decision-making, many EIAs are flawed by incomplete analysis of causal pathways, limited spatial assessment and a lack of transparency about how risks have been evaluated across the region. To address these, we describe an EIA methodology based on network analysis of potential causal pathways in a given region. This network approach is coupled with a systematic evaluation of the likelihood, consequence and mitigation options for each causal pathway from one or more human activities to multiple valued assets. The method includes analysis of the confidence in these evaluations, recognizing where knowledge gaps constrain assessments of risks to particular assets. The causal network approach is complemented by a spatially explicit analysis of the region that allows residual risk (i.e. risk remaining after all feasible mitigations) to be mapped for all valued assets. This identifies which activities could lead to potential impacts of varying concern (rated from 'very low' to 'very high'), their likely pathways, which valued assets are at risk and where these residual risks are greatest. The output maps reveal 'risk hotspots' where more detailed local-scale assessments and monitoring should focus. The method is demonstrated by application to potential impacts on 8 valued assets (aquifers, ecosystems and protected species) due to unconventional gas resource development in the Cooper Basin, central Australia. Results show which activities and causal pathways are of potential concern to different valued assets and where residual risk is greatest for particular species and ecosystems. This spatial causal network provides a systematic, consistent and transparent assessment of potential impacts, improving the quality of decision-making about planned developments and their environmental risks.

Frailty and sarcopenia-from theory to practice.

Frailty and sarcopenia have emerged as important syndromes in geriatrics. Their impact is far reaching and are associated with many poor outcomes in older adults. Assessment of frailty and sarcopenia should form part of the assessment in older adults at all encounters between healthcare staff and older adults, coupled with comprehensive geriatric assessment. Early interventions are warranted based on existing consensus guideline recommendations. Recently, strict lockdown measures to protect at-risk groups during the coronavirus disease 2019 pandemic may have led to worsening of frailty and sarcopenia among older adults, owing to social isolation, reduced access to care, and physical inactivity. Assessment and prevention of frailty and sarcopenia are of particular importance during pandemics. Further study is warranted to find the best strategies for managing frailty and sarcopenia.

Podocalyxin inhibits human embryo implantation in vitro and luminal podocalyxin in putative receptive endometrium is associated with implantation failure in fertility treatment.

OBJECTIVE: To study whether endometrial epithelial podocalyxin (PCX) inhibits implantation of human embryos in vitro and in patients undergoing in vitro fertilization (IVF). DESIGN: We have recently identified PCX as a key negative regulator of endometrial epithelial receptivity. Podocalyxin is expressed in all epithelial cells in the nonreceptive endometrium, but is selectively downregulated in the luminal epithelium (LE) for receptivity. In the current study, we first investigated whether high levels of PCX in Ishikawa monolayer inhibit attachment and/or penetration of human blastocysts in in vitro models. We then examined PCX by immunohistochemistry in putative receptive endometrial tissues biopsied from 81 IVF patients who underwent frozen embryo transfer in the next natural cycle and retrospectively analyzed the association between PCX staining in LE and clinical pregnancy as a proxy of successful implantation. SETTING: RMIT University, Australia; Vrije Universiteit Brussel, Belgium. PATIENT(S): In vitro fertilization patients undergoing frozen/thawed embryo transfer. INTERVENTION(S): N/A. MAIN OUTCOME MEASURE(S): Endometrial epithelial PCX inhibits implantation of human embryos in vitro and in IVF patients. RESULT(S): High levels of PCX in Ishikawa monolayer significantly inhibited blastocyst attachment and penetration. Among the 81 putative receptive tissues, 73% were negative, but 27% were heterogeneously positive for PCX in LE. The clinical pregnancy rate was 53% in those with a PCX-negative LE but only 18% in those with a PCX-positive LE. If LE was positive for PCX, the odds ratio of no clinical pregnancy was 4.95 (95% Confidence interval, 1.48-14.63). CONCLUSION(S): Podocalyxin inhibits embryo implantation. Assessment of PCX may aid the evaluation and optimization of endometrial receptivity in fertility treatment.

Podocalyxin is a key negative regulator of human endometrial epithelial receptivity for embryo implantation.

STUDY QUESTION: How is endometrial epithelial receptivity, particularly adhesiveness, regulated at the luminal epithelial surface for embryo implantation in the human? SUMMARY ANSWER: Podocalyxin (PCX), a transmembrane protein, was identified as a key negative regulator of endometrial epithelial receptivity; specific downregulation of PCX in the luminal epithelium in the mid-secretory phase, likely mediated by progesterone, may act as a critical step in converting endometrial surface from a non-receptive to an implantation-permitting state. WHAT IS KNOWN ALREADY: The human endometrium must undergo major molecular and cellular changes to transform from a non-receptive to a receptive state to accommodate embryo implantation. However, the fundamental mechanisms governing receptivity, particularly at the luminal surface where the embryo first interacts with, are not well understood. A widely held view is that upregulation of adhesion-promoting molecules is important, but the details are not well characterized. STUDY DESIGN, SIZE, DURATION: This study first aimed to identify novel adhesion-related membrane proteins with potential roles in receptivity in primary human endometrial epithelial cells (HEECs). Further experiments were then conducted to determine candidates' in vivo expression pattern in the human endometrium across the menstrual cycle, regulation by progesterone using cell culture, and functional importance in receptivity using in vitro human embryo attachment and invasion models. PARTICIPANTS/MATERIALS, SETTING, METHODS: Primary HEECs (n = 9) were isolated from the proliferative phase endometrial tissue, combined into three pools, subjected to plasma membrane protein enrichment by ultracentrifugation followed by proteomics analysis, which led to the discovery of PCX as a novel candidate of interest. Immunohistochemical analysis determined the in vivo expression pattern and cellular localization of PCX in the human endometrium across the menstrual cycle (n = 23). To investigate whether PCX is regulated by progesterone, the master driver of endometrial differentiation, primary HEECs were treated in culture with estradiol and progesterone and analyzed by RT-PCR (n = 5) and western blot (n = 4). To demonstrate that PCX acts as a negative regulator of receptivity, PCX was overexpressed in Ishikawa cells (a receptive line) and the impact on receptivity was determined using in vitro attachment (n = 3-5) and invasion models (n = 4-6), in which an Ishikawa monolayer mimicked the endometrial surface and primary human trophoblast spheroids mimicked embryos. Mann-Whitney U-test and ANOVA analyses established statistical significance at *P ≤ 0.05 and **P ≤ 0.01. MAIN RESULTS AND THE ROLE OF CHANCE: PCX was expressed on the apical surface of all epithelial and endothelial cells in the non-receptive endometrium, but selectively downregulated in the luminal epithelium from the mid-secretory phase coinciding with the establishment of receptivity. Progesterone was confirmed to be able to suppress PCX in primary HEECs, suggesting this hormone likely mediates the downregulation of luminal PCX in vivo for receptivity. Overexpression of PCX in Ishikawa monolayer inhibited not only the attachment but also the penetration of human embryo surrogates, demonstrating that PCX acts as an important negative regulator of epithelial receptivity for implantation. LIMITATIONS, REASONS FOR CAUTION: Primary HEECs isolated from the human endometrial tissue contained a mixture of luminal and glandular epithelial cells, as further purification into subtypes was not possible due to the lack of specific markers. Future study would need to investigate how progesterone differentially regulates PCX in endometrial epithelial subtypes. In addition, this study used primary human trophoblast spheroids as human embryo mimics and Ishikawa as endometrial epithelial cells in functional models, future studies with human blastocysts and primary epithelial cells would further validate the findings. WIDER IMPLICATIONS OF THE FINDINGS: The findings of this study add important new knowledge to the understanding of human endometrial remodeling for receptivity. The identification of PCX as a negative regulator of epithelial receptivity and the knowledge that its specific downregulation in the luminal epithelium coincides with receptivity development may provide new avenues to assess endometrial receptivity and individualize endometrial preparation protocols in assisted reproductive technology (ART). The study also discovered PCX as progesterone target in HEECs, identifying a potentially useful functional biomarker to monitor progesterone action, such as in the optimization of progesterone type/dose/route of administration for luteal support. STUDY FUNDING/COMPETING INTEREST(S): Study funding was obtained from ESHRE, Monash IVF and NHMRC. LR reports potential conflict of interests (received grants from Ferring Australia; personal fees from Monash IVF Group and Ferring Australia; and non-financial support from Merck Serono, MSD, and Guerbet outside the submitted work. LR is also a minority shareholder and the Group Medical Director for Monash IVF Group, a provider of fertility preservation services). The remaining authors have no potential conflict of interest to declare. TRIAL REGISTRATION NUMBER: NA.

Rapid Estimate of Inadequate Health Literacy (REIHL): development and validation of a practitioner-friendly health literacy screening tool for older adults.

INTRODUCTION: This study aimed to develop and validate a brief practitioner-friendly health literacy screening tool, called Rapid Estimate of Inadequate Health Literacy (REIHL), that estimates patients' health literacy inadequacy in demanding clinical settings. METHODS: This is a methodological study of 304 community-dwelling older adults recruited from one community health centre and five district elderly community centres. Logistic regression models were used to identify the coefficients of the REIHL score's significant factors. Receiver operating characteristic (ROC) curve analysis was then used to assess the REIHL's sensitivity and specificity. Path analysis was employed to examine the REIHL's criterion validity with the Chinese Health Literacy Scale for Chronic Care and concurrent validity with self-rated health scale and the Geriatric Depression Scale-15. RESULTS: The REIHL has scores ranging from 0 to 23. It had 76.9% agreement with the Chinese Health Literacy Scale for Chronic Care. The area under the ROC curve for predicting health literacy inadequacy was 0.82 (95% confidence interval=0.78-0.87, P<0.001). The ROC curve of the REIHL showed that scores ≥11 had a sensitivity of 77.8% and specificity of 75.6% for predicting health literacy inadequacy. The path analysis model showed excellent fit (Chi squared [2, 304] 0.16, P=0.92, comparative fit index 1.00, root mean square error of approximation <0.001, 90% confidence interval=0.00-0.04), indicating that the REIHL has good criterion and concurrent validity. CONCLUSION: The newly developed REIHL is a practical tool for estimating older adults' inadequate health literacy in clinical care settings.

Genome sequencing of human in vitro fertilisation embryos for pathogenic variation screening.

Whole-genome sequencing of preimplantation human embryos to detect and screen for genetic diseases is a technically challenging extension to preconception screening. Combining preconception genetic screening with preimplantation testing of human embryos facilitates the detection of de novo mutations and self-validates transmitted variant detection in both the reproductive couple and the embryo's samples. Here we describe a trio testing workflow that involves whole-genome sequencing of amplified DNA from biopsied embryo trophectoderm cells and genomic DNA from both parents. Variant prediction software and annotation databases were used to assess variants of unknown significance and previously not described de novo variants in five single-gene preimplantation genetic testing couples and eleven of their embryos. Pathogenic variation, tandem repeat, copy number and structural variations were examined against variant calls for compound heterozygosity and predicted disease status was ascertained. Multiple trio testing showed complete concordance with known variants ascertained by single-nucleotide polymorphism array and uncovered de novo and transmitted pathogenic variants. This pilot study describes a method of whole-genome sequencing and analysis for embryo selection in high-risk couples to prevent early life fatal genetic conditions that adversely affect the quality of life of the individual and families.

Assessment and diagnosis of dementia: a review for primary healthcare professionals.

Dementia is one of the most costly, disabling diseases associated with ageing, yet it remains underdiagnosed in primary care. In this article, we present the comprehensive approach illustrated with a classical case for diagnosing dementia which can be applied by healthcare professionals in primary care. This diagnostic approach includes history taking and physical examination, cognitive testing, informant interviews, neuropsychological testing, neuroimaging, and the utility of cerebrospinal fluid biomarkers. For the differential diagnosis of cognitive impairment, the differences and similarities among normal ageing, mild cognitive impairment, depression, and delirium are highlighted. As primary care physicians are playing an increasingly prominent role in the caring of elderly patients in an ageing population, their role in the diagnosis of dementia should be strengthened in order to provide a quality care for patients with dementia.

Assessment of potential biomarkers of pre-receptive and receptive endometrium in uterine fluid and a functional evaluation of the potential role of CSF3 in fertility.

The endometrium lines a women's uterus becoming receptive, and allowing embryo implantation to occur, for just a few days during the post-ovulatory mid-secretory phase of each menstrual cycle. We investigated whether concentrations of proposed receptivity biomarkers (VEGF, IL8, FGF2, CSF3 sFlt-1, sGP130 and PlGF) secreted by the endometrium into the uterine cavity and forming the microenvironment for embryo implantation is altered among a population of age-matched women with unexplained (idiopathic) infertility compared to fertile women during the receptive mid-secretory phase (n = 16 fertile, 18 infertile) and the prior pre-receptive early secretory phase (n = 19 fertile, 18 infertile) of their cycle. In the mid-secretory cohort significantly elevated concentrations of five biomarkers; PlGF (p = 0.001), IL8 (p = 0.004), sGP130 (p = 0.009), sFlt-1 (p = 0.021), and CSF3 (p = 0.029) was present in uterine fluid of infertile women during the mid-secretory phase, but only CSF3 was significantly elevated in the pre-receptive early secretory phase (p = 0.006). In vitro studies of glycosylated and non-glycosylated forms of CSF3 at representative fertile (20 ng/mL) and infertile (70 ng/mL) effects on endometrium and embryo behaviour were performed. Non-glycosylated CSF3 at fertile concentrations significantly (p < 0.001) elevated endometrial epithelial cell proliferation however chronic treatment or elevated (infertile) concentrations of CSF3 in glycosylated form abrogated the positive effects. Both forms of CSF3 increased trophoblast cell invasion (p < 0.001) regardless of concentration. Mouse embryo outgrowth was significantly (p < 0.01) increased at fertile but not at infertile concentrations. The study confirmed potential utility of five biomarkers of endometrial receptivity for future application in the mid-secretory phase while highlighting CSF3 is elevated in the earlier pre-receptive phase. Our data provides evidence that CSF3 acts on both human endometrium and embryo in a manner that is concentration and glycosylation dependent.

Idiopathic infertility in women is associated with distinct changes in proliferative phase uterine fluid proteins.

The regenerative, proliferative phase of a woman's menstrual cycle is a critical period which lays the foundation for the subsequent, receptive secretory phase. Although endometrial glands and their secretions are essential for embryo implantation and survival, the proliferative phase, when these glands form, has been rarely examined. We hypothesized that alterations in the secreted proteome of the endometrium of idiopathic infertile women would reflect a disturbance in proliferative phase endometrial regeneration. Our aim was to compare the proteomic profile of proliferative phase uterine fluid from fertile (n = 9) and idiopathic infertile (n = 10) women. Proteins with ≥2-fold change (P < 0.05) were considered significantly altered between fertile and infertile groups. Immunohistochemistry examined the endometrial localization of identified proteins. Western immunoblotting defined the forms of extracellular matrix protein 1 (ECM1) in uterine lavage fluid. Proteomic analysis identified four proteins significantly downregulated in infertile women compared to fertile women, including secreted frizzled-related protein 4 (SFRP4), CD44, and ECM1: two proteins were upregulated. Seven proteins were unique to the fertile group and six (including isoaspartyl peptidase/L-asparaginase [ASRGL1]) were unique to the infertile group. Identified proteins were classified into biological processes of tissue regeneration and regulatory processes. ASRGL1, SFRP4, and ECM1 localized to glandular epithelium and stroma, cluster of differentiation 44 (CD44) to stroma and immune cells. ECM1 was present in two main molecular weight forms in uterine fluid. Our results indicate a disturbance in endometrial development during the proliferative phase among infertile women, providing insights into human endometrial development and potential therapeutic targets for infertility.

End-of-life services for older people in residential care homes in Hong Kong.

Good end-of-life care is needed for older people living in residential care homes with advanced irreversible chronic medical illnesses and cancers. At present, the usual practice of residential care homes is to send older residents to acute care hospitals when they are unwell, and some residents will die in hospital. Dying in hospital without choice for older people may not be in alignment with the principle of 'good death'. There are many barriers for older people to die in the place of their choice, particularly in a residential care home. In the community, to enhance end-of-life care for elderly people living in residential care homes, pilot end-of-life programmes have been organised by community geriatric assessment teams. In 2015, the Hong Kong Hospital Authority started the 'Enhance community geriatric assessment team support to end-of-life patients in residential care homes for the elderly' programme in four clusters. In the hospital setting, an end-of-life clinical plan and end-of-life ward in geriatric step-down hospitals may improve the quality of death of elderly people. In September 2015, the Hospital Authority guideline on life-sustaining treatment for terminally ill people was updated. Among other key end-of-life issues, careful (comfort) hand feeding was first mentioned in the guideline. The possible establishment of enduring powers of attorney for health care decision-making and enhancement of careful (comfort) hand feeding are new developments in the coming years.

Health outcomes of school-aged children conceived using donor sperm.

The use of donor sperm is increasing, yet limited information is available about the health and development of children conceived from donor sperm. This retrospective descriptive study aimed to assess health and development in a cohort of school-aged children who were conceived using donor sperm. Participants included 224 children, aged 5-11 years, who were conceived using donor sperm. Participants' mothers completed a questionnaire comprising validated scales examining their child's current and past physical, psychosocial and mental health, healthcare needs and child development, as well as the mothers' health and wellbeing. At the conclusion of the study, the response rate was 296 out of 407 (72.7%), with a participation rate of 224 out o 407 (55.0%). Compared with the normative Australian population, sperm donor-conceived children had similar physical, psychosocial and mental health and development. A modest increase in healthcare needs was evident. The study concludes that in school-aged children conceived using donor sperm, most aspects of child health and wellbeing are similar to the general population.

The feeding paradox in advanced dementia: a local perspective.

Feeding problems are common in older people with advanced dementia. When eating difficulties arise tube feeding is often initiated, unless there is a valid advance directive that refuses enteral feeding. Tube feeding has many pitfalls and complications. To date, no benefits in terms of survival, nutrition, or prevention of aspiration pneumonia have been demonstrated. Careful hand feeding is an alternative to tube feeding with advanced dementia. In Hong Kong, the Hospital Authority has established clear ethical guidelines for careful hand feeding. Notwithstanding, there are many practical issues locally if tube feeding is not used in older patients with advanced dementia. Training of doctors, nurses, and other members of the health care team is vital to the promulgation of careful hand feeding. Support from the government and Hospital Authority policy, health care staff training, public education, and promotion of advance care planning and advance directive are essential to reduce the reliance on tube feeding in advanced dementia.

The proliferative phase underpins endometrial development: Altered cytokine profiles in uterine lavage fluid of women with idiopathic infertility.

Endometrial gland development occurs during the proliferative phase of a woman's menstrual cycle, laying the foundation for the subsequent receptive, secretory phase when pregnancy is established. Idiopathic infertility has been rarely investigated with respect to the proliferative phase endometrium. We investigated whether gland development and/or altered secretion of cytokines during the proliferative phase is associated with infertility. Area of the glandular epithelium (GE) was measured in proliferative phase endometrial tissue collected from fertile (n=18) and infertile (n=14) women. Cytokines were measured in proliferative phase uterine lavage of fertile (n=15) and infertile (n=15) women. Immunohistochemistry determined cellular localisation of transforming growth factor alpha (TGFα) and interferon gamma (IFNγ) in proliferative phase endometrial tissue. For statistical analysis the cohort was divided into women <35years and ⩾35years. There were no significant differences in GE area of infertile and fertile women. C-C motif chemokine 11 (P=0.048), TGFα (P=0.049), IFNγ (P=0.033) and interleukin-1 alpha (P=0.047) were significantly elevated in uterine lavage from infertile women <35years compared to fertile but not in women ⩾35years. TGFα and IFNγ localised predominantly to GE in both the fertile and infertile endometrium. The potential impact of this altered proliferative phase environment on subsequent receptivity is discussed.

A High-Throughput Assay for the Detection of α-Dystroglycan N-Terminus in Human Uterine Fluid to Determine Uterine Receptivity.

Embryo implantation requires a healthy embryo and a receptive uterus. In women, the uterus remains a hostile environment and must undergo functional changes to convert to a receptive state for embryo implantation. Determining uterine receptivity is vital in IVF treatment, as the timing of embryo transfer needs to be synchronized with uterine receptivity. However, to date, no reliable biochemical tests are available to determine uterine receptivity. We recently established that removal of α-dystroglycan N-terminus (α-DG-N) from the uterine surface plays an important role in the establishment of uterine receptivity. Importantly, the α-DG-N removed from the uterine tissue enters into the uterine fluid, and the levels correlate with the tissue status of receptivity. Detection of α-DG-N in uterine fluid may therefore provide a nonsurgical approach to assess uterine receptivity. In this study, we first validated three monoclonal antibodies raised against α-DG-N in our system, and then established a sandwich ELISA suitable for the detection of α-DG-N in human uterine fluid. This ELISA detected significantly higher concentrations of α-DG-N in uterine fluid of women in the receptive phase. We believe this newly established α-DG-N ELISA may provide an important tool in the development of noninvasive strategies to detect uterine receptivity in women.

Posttranslational removal of α-dystroglycan N terminus by PC5/6 cleavage is important for uterine preparation for embryo implantation in women.

Embryo implantation requires a healthy embryo and a receptive endometrium (inner lining of the uterus); endometrial receptivity acquisition involves considerable epithelial surface remodeling. Dystroglycan (DG), a large cell surface glycoprotein, consists of α- and ß-subunits; ß-DG anchors within the plasma membrane whereas α-DG attaches extracellularly to ß-DG. The glycosylated central α-DG mediates adhesion, but it is obstructed by its large N terminus (α-DG-N); α-DG-N removal enables DG's adhesive function. We demonstrate here that full-length α-DG in the human endometrial epithelium is a barrier for embryo attachment and that removal of α-DG-N by proprotein convertase 5/6 (PC6; a protease critical for implantation) regulates receptivity. This was evidenced by: 1) α-DG contains a PC6-cleavage site near α-DG-N, and PC6 cleaves a peptide harboring such a site; 2) PC6 knockdown reduces α-DG-N removal from endometrial epithelial cell surface and blastocyst adhesion; 3) mutating the PC6-cleavage site prevents α-DG-N removal, causing cell surface retention of full-length α-DG and loss of adhesiveness; 4) α-DG-N is removed from endometrial tissue in vivo for receptivity and uterine fluid α-DG-N reflects tissue removal and receptivity. We thus identified α-DG-N removal as an important posttranslational control of endometrial receptivity and uterine fluid α-DG-N as a potential biomarker for receptivity in women.