Pregnancy-associated plasma protein-A and placental protein 5 in human ovarian follicular fluid

Tissue factor pathway inhibitor 2: Current understanding, challenges, and future perspectives

AIM

Tissue factor pathway inhibitor 2 (TFPI2) is a structural homolog of tissue factor pathway inhibitor 1 (TFPI1). Since TFPI2 is a placenta-derived protein, dynamic changes in TFPI2 levels may be related to pregnancy-related diseases. Furthermore, TFPI2 has been reported to be a novel serum biomarker for detecting ovarian cancer, especially clear cell carcinoma (CCC). This review aims to summarize the current knowledge on the biological function of TFPI2, highlight the major challenges that remain to be addressed, and discuss future research directions.

METHODS

Papers published up to March 31, 2023 in the PubMed and Google Scholar databases were included in this review. We also provide novel complementary information to what is known about the action of TFPI2.

RESULTS

Since TFPI2 concentrations in the blood of pregnant women, preeclampsia patients, and cancer patients vary greatly, its pathophysiological functions have attracted attention. Downregulation of TFPI2, a tumor-suppressor gene, by hypermethylation may contribute to the progression of several cancers. On the other hand, TFPI2 overexpressed in CCC is a risk factor for the development of thrombosis, possibly through inhibition of plasmin activity. However, agreement on the biological function of TFPI2 is still lacking and there are many scientific questions to be addressed. In particular, the lack of international standardization for the quantification of TFPI2 concentrations makes it difficult for researchers and clinicians to evaluate, pool, and compare data from different studies across countries.

DISCUSSION

This review summarizes current understandings and challenges in TFPI2 research and discusses future perspectives.

Pain Symptoms and Peritoneal Fluid Cytokine and Marker Concentrations in Women with and without Endometriosis

Purpose

Endometriosis is not only associated with infertility, it is also a common cause of pain in women, leading to work absenteeism and a reduced quality of life. The objective of this study was to confirm the increased peritoneal fluid (PF) concentration of several cytokines in endometriosis patients, to investigate their association with pain levels, and to identify new biological markers in the PF which are neurostimulatory and thus responsible for the appearance and severity of different types of pain.

Methods

Our sample group included 111 patients with histologically confirmed endometriosis and 47 controls undergoing laparoscopy for reasons of abdominal pain or infertility. They rated their pain during menstruation, during sexual intercourse and general lower abdominal pain prior to undergoing surgery in our clinic using a visual analogue scale. During laparoscopy, PF was aspirated. Marker cytokine concentrations were measured by immunoassay and correlated to the Revised American Fertility Society (rAFS) stage of endometriosis and to the pain level using non-parametric methods.

Results

Differences were found between the correlations of the peritoneal fluid levels of many cytokines with dysmenorrhea or lower abdominal pain, and with the presence of severe endometriosis (rAFS III+IV). Glycodelin and osteoprotegerin (OPG) show the strongest associations with menstrual pain, while IL-8, MCP-1 and OPG were correlated to the stage of endometriosis. Low density cytokine protein arrays did not contribute to finding new markers for endometriosis and pain.

Conclusions

These findings illustrate the large variation of cytokine levels between patients. Glycodelin, IL-8 and OPG are the most likely targets for further investigations towards their future clinical use.

Correlation between symptoms of pain and peritoneal fluid inflammatory cytokine concentrations in endometriosis

Endometriosis affects 10-20% of women during reproductive age and is a common cause of infertility and pain leading to work absenteeism and reduced quality of life.The objective of this study was to investigate the association between the presence and concentration of interleukin-8 (IL-8), RANTES, osteoprotegerin (OPG), pregnancy-associated plasma protein A (PAPP-A), tumour necrosis factor-alpha (TNF-alpha), midkine and glycodelin in the peritoneal fluid (PF) and the intensity of pain reported by patients undergoing laparoscopy in our clinic. They rated their pain during menstruation, intercourse and lower abdominal using a visual analogue scale. During laparoscopy, PF was aspirated. Pain scores were correlated to the concentration of the above substances in the PF and to the stage of endometriosis. Endometriosis was histologically confirmed in 41 of 68 participating women; 27 without such evidence were considered as controls. TNF-alpha and glycodelin correlated positively with the level of menstrual pain. For IL-8, RANTES, OPG and PAPP-A no correlation between their PF concentration and the menstrual pain scores was observed. Patients with severe dysmenorrhoea had increased PF cytokine and marker levels; the difference was significant for TNF-alpha and glycodelin when compared with the other patients (no or moderate pain). TNF-alpha and glycodelin may thus play a role in endometriosis and the severity of menstrual pain.

Ryudocan expression by luteinized granulosa cells is associated with the process of follicle atresia

OBJECTIVE

To evaluate the presence of ryudocan in follicular fluid (FF) and its possible correlation with FF E(2) and P, and to study the levels of ryudocan in granulosa-lutein cells stimulated with hCG.

DESIGN

Controlled clinical study and in vitro experiment.

SETTING

University teaching hospital.

PATIENT(S)

One hundred seven patients undergoing IVF.

INTERVENTION(S)

The FF and granulosa-lutein cells were aspirated from follicles 34 hours after an ovulatory gonadotropin bolus.

MAIN OUTCOME MEASURE(S)

FF ryudocan, E(2), and P levels as well as hCG-mediated induction of ryudocan.

RESULT(S)

Ryudocan was abundant in the FF; the concentration of ryudocan in human FF was estimated to be 305.5 +/- 200.8 ng/mL (mean +/- SD). Atretic follicles had higher concentrations of ryudocan (559.1 +/- 156.5 ng/mL). FF ryudocan levels were inversely correlated with FF E(2) (r = -0.5023) and P concentrations (r = -0.4459). A detectable amount of ryudocan was found in pooled granulosa-lutein cells. Ryudocan production was augmented by surge levels of hCG.

CONCLUSION(S)

Ryudocan is expressed in luteinized granulosa cells in vitro. The higher concentrations of ryudocan in FF of atretic follicles suggest an involvement of ryudocan in the process of atresia.

Immunological heterogeneity of pregnancy-associated plasma protein-A (PAPP-A). Effects on the radioimmunoassay of PAPP-A

Pregnancy-associated plasma protein-A (PAPP-A) is a macromolecular glycoprotein produced by the trophoblast during pregnancy. Because the presence of PAPP-A in non-pregnant females is controversial, we re-evaluated our own radioimmunoassay technique for PAPP-A in the light of new observations about its immunological heterogeneity. Irrespective of the antibody (Geneva anti-PAPP-A or Dako anti-PAPP-A) the use of EDTA pregnancy plasma instead of pregnancy serum as a standard yielded different slopes of the standard curves and estimated significantly different amounts of PAPP-A in test samples. Moreover, highly purified tracers, isolated from maternal EDTA pregnancy plasma or pregnancy serum also produced significantly different results. So that the use of a tracer purified from EDTA plasma and EDTA pregnancy plasma as a standard will yield measurable levels of PAPP-A in non-pregnant female serum whereas the use of a tracer purified from maternal pregnancy serum and maternal pregnancy serum as a standard will not detect PAPP-A in the same samples. We conclude that, irrespective of the antiserum used, but depending on the biological origin of the tracer and the standard, different results will be obtained. PAPP-A is clearly immunologically heterogeneous, and the immunorecognition of PAPP-A will depend on whether or not blood coagulation has taken place.

Intraovarian markers of follicular and oocyte maturation

The use of ovulation induction for multiple follicular growth in in vitro fertilization (IVF) has introduced the problem of follicular asynchrony. As a consequence of the asynchrony, the parameters most commonly used by IVF groups to assess follicular and oocyte quality within those follicles are not sufficiently sensitive or specific. Thus, each follicle must be considered separately, and specific markers of follicular and/or oocyte maturation must be sought from within the follicle. In this review we analyze previous reports of potential markers of follicular and oocyte maturation. In regards to the follicular fluid constituents, the level of estradiol in follicular fluid correlates with fertilization and pregnancy in stimulated cycles. Other steroids are only helpful when specific stimulation protocols are used. The level of some follicular proteins such as alpha-1-antitrypsin and fibrinogen also correlates with fertilization and pregnancy outcome. Cyclic AMP levels in follicular fluid are significantly reduced in follicles leading to conception. Regulators of oocyte maturation, such as the Oocyte Maturation Inhibitor (OMI) or the Meiosis Inducing Substance (MIS) have also been correlated with IVF outcome, but their exact structure remains still unknown. In addition, other sophisticated parameters, such as chemotactic activity of human leukocytes, or simple methods, such as the presence of intrafollicular echoes, have also been used as successful markers in predicting IVF outcome.