N-glycans from serum IgG and total serum glycoproteins specific for endometriosis

Endometriosis is a chronic inflammatory gynaecological disease characterized by the growth of endometrial tissue outside the uterine cavity. There are currently no definitive non-invasive diagnostic tools. Glycosylation is the most common posttranslational modification of proteins and altered glycosylation has been found in many diseases, including chronic inflammatory conditions and cancer. Sialylation and galactosylation on serum IgG have previously been found to be altered in endometriosis and serum sialylation changed after Zoladex (Goserelin Acetate) therapy. Using IgG and whole serum glycoproteins, we investigated N-glycosylation in two clinical cohorts of women with and without endometriosis. PNGase F-digested serum samples were fluorescently labelled and N-glycans were profiled by ultra-performance liquid chromatography. Clinical data was collected to link glycomic findings with metabolic and hormonal profiles. Total serum glycoprotein and IgG glycosylation differed in patients with endometriosis compared to control cases. The most significantly altered was glycan peak 3 from IgG, containing bisected biantennary glycans, which was decreased in the endometriosis cohorts (p = 0.0000005-0.018). In conclusion, this is the first pilot study to identify changes in N-glycans from whole serum glycoproteins associated with endometriosis. A larger validation study is now warranted and such studies should include the follow-up of surgically and pharmacologically treated patients.

P–305 The expression of innate immune factors in the eutopic endometrium of women with endometriosis

Study question

Is the expression of IL–17A and antimicrobial peptides (AMPs) altered in endometriosis?

Summary answer

IL–17A protein levels were similar in the endometrium of women with and without endometriosis but the expression of several AMPs was reduced in endometriosis.

What is known already

Chronic inflammation and aberrant immune signalling in the eutopic endometrium underlies the pathophysiology of endometriosis. Endometrial IL–17 levels have previously been shown by our group to be negatively correlated with successful pregnancy. IL–17 has also been associated with endometriosis. Among its immunomodulatory functions, IL–17 regulates the expression of several antimicrobial peptides (AMPs), highly conserved proteins that are involved in the innate immune response. Despite the well accepted paradigm of immune dysregulation in endometriosis, surprisingly little is known about the relationship between endometrial IL–17, AMPs and endometriosis, particularly in the context of infertility.

Study design, size, duration

This was a prospective cohort study. Endometrial biopsy samples were collected at the time of endometrial scratch testing, or during elective laparoscopy, over a 15-month period. The aim was to evaluate and compare IL–17A protein levels and the expression of specific AMPs (SLPI, elafin, beta-defensin 1, S100A7, S100A8, S100A9) [MW1] , in the endometrium of patients with endometriosis, and those without the disease.

Participants/materials, setting, methods

Thirty-two patients were recruited for the study, with 26 included in the final analysis. Biopsies were obtained at the time of planned endometrial scratch (mid-luteal phase) prior to ART (n = 7), or at the time of laparoscopy (n = 19). RNA was extracted and Q-PCR analysis for AMP transcript levels was performed. ELISA was carried out to quantify levels of IL–17A in endometrial tissue in a subgroup (n = 17). Main results and the role of chance: In our cohort IL–17A protein levels were not significantly different in the endometrium of patients with disease compared to those without (p = 0.3636). The expression of the AMPs elafin, SLPI, BD1 and S100A9, as measured by a Q-PCR transcript profiling approach, were found to be significantly reduced in the eutopic endometrium in cases of endometriosis as compared to cases without endometriosis. There was no significant difference in AMP expression between disease stages. No demonstrable difference in IL–17A protein levels, or AMP expression was detected between the proliferative and secretory phases of the menstrual cycle.

Limitations, reasons for caution

Numbers may not have been large enough to fully evaluate the impact of endometriosis stage or the effect of cycle phase. While all patients with endometriosis had surgical confirmation of disease, not all patients in the control cohort had a laparoscopy, though they had no clinical features suggestive of endometriosis.

Wider implications of the findings: Our findings indicate that the innate immune environment of the eutopic endometrium is altered in endometriosis. Endometrial expression of AMPs was diminished in endometriosis, independent of disease stage. This work supports the model of dysregulated innate immune system in endometriosis, and reveals AMPs as novel immune players in disease pathogenesis.

Trial registration number

Not applicable

P–340 Novel non-invasive diagnostic options for endometriosis - based on glycome analysis

Study question

Could glycosylation changes on serum and/or urine glycoproteins be suitable biomarkers for the non-invasive diagnosis of endometriosis?

Summary answer

The glycosylation pattern on serum and urine glycoproteins differed significantly in endometriosis patients compared to controls, suggesting a novel role as biomarkers of the disease.

What is known already

There is little published on endometriosis and glycosylation, and most of the studies are conducted with tissue or peritoneal fluid samples, collected by invasive means. An Iraqi study draws attention to the importance of serum sialylation, which is dramatically changed in endometriosis patients after zoladex therapy, indicating that changes in serum sialylation may be a new biomarker of the disease. While glycosylation of urine in endometriosis has not been studied so far, in a study of endometrial cancer, the urinary level of two glycoproteins was significantly increased in the patients compared to the control group.

Study design, size, duration

This was a prospective study. In this basic research project, serum and urine samples were collected for glycome analysis in women with and without endometriosis, as diagnosed at laparoscopy. Glycated haemoglobin (HbA1c), fasting glucose levels as well as hormone levels were also collected from the patients to link our glycomic findings with metabolic and hormone profiles. The study was approved by the Research and Ethics Committee of the National Maternity Hospital, Dublin (EC19.2018).

Participants/materials, setting, methods

Samples from 24 cases of endometriosis (patients without previous anti-inflammatory or hormonal therapy, endometriosis was confirmed by laparoscopy) and 27 control patients (patients without endometriosis) were processed to analyse N-glycans (total serum), urine glycoproteins, and IgG. The pre-processed, PNGase F-digested serum and urine samples were labelled with fluorescent tag and then analysed by mass spectrometry, ultra-performance liquid chromatography (UPLC) in combination with exoglycosidase digestions and Glycostore (https://glycostore.org/).

Main results and the role of chance

Glycosylation on total serum and urine glycoproteins and IgG was investigated and differed in endometriosis compared to controls. The N-glycome from the total glycoproteins in serum and urine was also different. The proportion of the galactosylation and sialylation differed between urine and serum IgG and these alterations have an impact on the IgG function. Our preliminary data indicate, that there is an increase in alpha 2–3 sialylation, galactosylation, and fucosylation on urine glycans from endometriosis patients compared to the control pool. Urine is a good source of biomarkers as it can be collected non-invasively. Our group is the first to have developed a protocol for the recovery of N-glycans in urine and to have identified the total N-glycome in urine. The urine N-glycome contains mostly complex N-glycans and also some oligomannosylated and hybrid glycans. Our results may lead to non-invasive biomarkers for the diagnosis of endometriosis and the monitoring of the disease.

Limitations, reasons for caution

The number of participants involved in this basic research is low but this is a pilot study. A larger, validation study, is warranted in the future. Furthermore, the follow-up of treated patients also would be an interesting field of research.

Wider implications of the findings: Glycomics may be a potent source of biomarkers of endometriosis, with a number of glyco-biomarkers already approved by the FDA. Endometriosis-associated glycomic profiles from serum and/or urine glycoproteins may represent viable targets for development of innovative non-invasive or minimally invasive diagnostics in this debilitating disease.

Trial registration number

Not applicable

Holoprosencephaly: antenatal and postnatal diagnosis and outcome

OBJECTIVES

The objectives of this study are to ascertain the clinical outcome and overall survival of holoprosencephaly (HPE) patients diagnosed antenatally and postnatally, to determine the accuracy of antenatal diagnosis and to determine the role of neurosurgical intervention in HPE.

DESIGN

This is a retrospective review over a 10-year period.

PATIENTS

Sixty-three patients were included in the study, 45 were diagnosed by antenatal radiological imaging and 18 were diagnosed by postnatal radiological imaging. Patient data was drawn from Temple Street Children's University Hospital (the national paediatric neurosurgery centre), the National Maternity Hospital in Holle's Street, Dublin, and Our Lady of Sick Children Hospital, Dublin.

METHODS

The study was carried out through a review of antenatal and postnatal radiological imaging and reports, clinical charts, GP letters from patient follow-up and telephone conversations with parents of HPE patients.

RESULTS

Four patients in the antenatal diagnosis group had follow-up foetal MRI confirming HPE. Twelve in this group had radiological follow-up postnatally, and in five of these, HPE was confirmed. The remaining seven were identified as false positive. Alobar HPE constituted 55 % (21/38) of patients with 95 % mortality. Fifty-one percent had a normal karyotype. The overall survival in the antenatal diagnosis group was 13 %. In the postnatal group, 18 patients were identified, 67 % (12/18) lobar and 33 % (6/18) semilobar. Normal karyotype was found in 72 % (13/18), with an overall survival rate of 56 % (10/18). Neurosurgical intervention in both groups mainly consisted of CSF diversion in the form of ventriculoperitoneal (VP) or cystoperitoneal shunt (CP) (13/67).

CONCLUSION

Foetal MRI should be routinely performed in suspected cases of HPE, and reliance on ultrasound alone in the antenatal period may not be sufficient. In our study, there is a high early mortality noted in severe cases of HPE, while milder forms of HPE in children tend to survive beyond infancy albeit with associated complications that required neurosurgical intervention and medical management for other associated systemic anomalies.