P–238 Impaired oocyte fertilization is associated with a proinflammatory M1 phenotype of macrophages and the activation of the NLRC4 inflammasome

Study question

Are inflammatory signatures in the blood of clinically asymptomatic patients predictive for oocyte fertilization success in ART treatment?

Summary answer

The proinflammatory M1 phenotype of macrophages combined with increasing numbers of cytotoxic T-cells and an upregulated inflammasome NLRC4 is associated with impaired oocyte fertilization.

What is known already

Oocyte fertilization is an indispensable step towards embryogenesis and reproductive success. Patients with acute or chronic inflammation are at risk of reduced fertilization rates and failure of assisted reproductive technology (ART) treatment. Inflammasomes are intracellular multiprotein complexes that mediate inflammatory tissue remodeling. They can be activated by endogenous and exogenous stimuli and result in maturation of the cytokines IL–1βand IL–18. Appropriate inflammasome activation serves for pathogen defense and tissue damage repair, while aberrant activation of inflammasomes can enhance uncontrolled tissue damage.

Study design, size, duration

This a prospective study including 39 patients stratified by fertilization rate (cut off 66%) of mature M II oocytes after ICSI procedure, compares 20 patients with high (mean 84,8%, range 67 –100%) versus 19 patients with low (mean 29.4%, range 0–65%) rates.

Participants/materials, setting, methods

We performed FACS analysis of immune cell composition (leukocytes, neutrophils, monocytes, macrophage types M1 and M2, cytotoxic T-cells, T-helper cells) and utilized RT-qPCR analysis of three inflammasomes (AIM 2, NLRP3 and NLRC4) and their down-streaming proteins caspase 1 and IL–1ß. We focused on an initial and a late state during controlled ovarian stimulation (COS) procedure.

Main results and the role of chance

This study reports a cellular and molecular inflammatory signature associated with reduced oocyte fertilization rates after ICSI treatment in clinically asymptomatic patients.

On a cellular level proinflammatory M1 macrophages were significantly elevated in the low fertilization group (p < 0.01), additionally the ratio of proinflammatory M1 macrophages to anti-inflammatory M2 phenotype was inversely associated with oocyte fertilization rate (p < 0.001). Cytotoxic T cells (p < 0.05) and the inflammasome NLRC4 (p < 0.01) revealed identical patterns of association with fertilization rates in the group comparison.

In line with this pattern, there was a significant upregulation of Caspase 1 with a consecutive increase in IL–1ß activity in women with low fertilization rates (p < 0.05).

No significant association was shown for the other tested immune cells (leukocytes, neutrophils, monocytes, T-helper cells) and inflammasomes (NLRC3, AIM2).

Limitations, reasons for caution

The preliminary results in this small study indicate an activation of the inflammasome NLRC4. This, however, has to be assessed on the protein level in a larger group of patients.

Wider implications of the findings: Systemic macrophage augmentation of M1 phenotype and cytotoxic T cell presence in combination with upregulated inflammasome NLRC4 are associated with impaired oocyte fertilization. The predictive information of the identified immunologic signature could indicate targeted treatment to down regulate systemic inflammation and the use of oocyte activators in the ART laboratory.

Trial registration number

none

Steroid hormones and human choriogonadotropin influence the distribution of alpha6-integrin and desmoplakin 1 in gland-like endometrial epithelial spheroids

In human glandular endometrial epithelial cells, desmosomal and adherens junction proteins have been shown to extend from a subapically restricted lateral position to the entire lateral membrane during the implantation window of the menstrual cycle. Similarly, a menstrual cycle stage-dependent redistribution of the extracellular matrix adhesion protein α6-integrin has been reported. These changes are believed to be important for endometrial receptiveness and successful embryo implantation. To prove the hypothesis that steroid hormones and human choriogonadotropin can induce the redistribution of these adhesion molecules, we used the human endometrial cell line Ishikawa in a 3D culture system. Gland-like spheroids were grown in reconstituted basement membrane (Matrigel™). The lumen-bearing spheroids were treated for 2 or 4 days with ovarian steroids or human choriogonadotropin and then assessed by immunofluorescence microscopy. In addition, human endometrial biopsies were obtained from patients, who were in therapy for assisted reproductive technology, and were examined in parallel. Lateral redistribution of the desmosomal plaque protein desmoplakin 1 was observed in the spheroids treated either with progesterone, medroxyprogesterone acetate or human choriogonadotropin. Furthermore, the extracellular matrix adhesion protein α6-integrin showed an increased lateral membrane localization upon gestagen stimulation in the 3D culture system. The results of this study demonstrate that the 3D endometrial Ishikawa cell culture might be suited as an experimental model system to prove the effect of hormonal changes like those occurring during the window of implantation.

Oocyte zona birefringence intensity is associated with embryonic implantation potential in ICSI cycles

A retrospective study recently showed that oocytes presenting with a high birefringence of the inner zona layer were more often associated with conception cycles. To further investigate these findings, a prospective study was conducted between September 2005 and September 2006 including intracytoplasmic sperm injection (ICSI) cycles presenting with at least two embryos for transfer. Using a polarization imaging system, oocytes were classified prior to ICSI treatment as having either a high zona birefringence (HZB) or a low zona birefringence (LZB) of the zona pellucida. Using zona birefringence as the only selection criterion, two fertilized oocytes, preferably derived from HZB oocytes, were selected for further culture and transfer. The required criteria were met by 135 ICSI cycles (124 patients; 34.9 +/- 4.1 years of age). Embryos for transfer were used in 20 cycles derived from HZB/HZB oocytes, in 50 cycles from HZB/LZB oocytes and in 65 from LZB/LZB oocytes. The corresponding implantation (P < 0.025), pregnancy (P < 0.005) and live birth (P < 0.025) rates were significantly different between HZB/HZB and HZB/LZB versus LZB/LZB group. Embryo development was superior in embryos derived from HZB oocytes. This study concludes that oocyte zona birefringence is a good selection criterion and a good predictive criterion for embryo implantation potential.

Orofaciodigital syndrome Type IV (Mohr-Majewski): early prenatal diagnosis in siblings

We report the sonographic and autopsy findings in two sibling fetuses with autosomal recessive orofaciodigital syndrome (OFDS) Type IV (Mohr-Majewski) diagnosed at 11-13 weeks' gestation. The first-trimester anomaly scan showed a markedly increased nuchal translucency (NT) thickness in both fetuses (4.7 mm and 5.1 mm). Both fetuses had multiple anomalies involving the brain, cranium, heart and skeletal system and their karyotypes were normal. The pregnancies were terminated and the autopsies showed findings consistent with Mohr-Majewski syndrome. These cases show the overlap between OFDS Type II (Mohr) and lethal short-rib-polydactyly syndrome Type II (Majewski) and confirm both the autosomal recessive inheritance of the condition and our ability to diagnose it early in pregnancy using detailed fetal ultrasonography.

First-trimester treatment of fetal anemia secondary to parvovirus B19 infection

Here we report two cases of first-trimester parvovirus B19 (PV-B19) infection that were successfully treated by intrauterine blood transfusion into the umbilical vein. At 13 weeks' gestation both fetuses presented with increased nuchal translucency (NT) and cardiomegaly. In both cases pulsed Doppler ultrasound examination of the fetal middle cerebral artery (MCA) revealed increased peak systolic velocity (PSV), which led to a suspicion of fetal anemia. Maternal PV infection was confirmed by a positive polymerase chain reaction result. Each fetus received a 3-mL intravenous transfusion of packed red blood cells into the umbilical vein, using a 25-G spinal needle. Follow-up ultrasound and Doppler examination demonstrated fetal well-being, decline of the MCA-PSV and resolution of the NT. Case 1 was readmitted at 25 weeks' gestation with severe hydrops fetalis, and both mother and fetus still tested positive for PV-B19 DNA. Three more intrauterine blood transfusions were performed and the fetal hydrops resolved. In Case 2 no additional transfusions were needed. Both babies had a good neonatal outcome and uneventful follow-up. Our findings demonstrate that the MCA-PSV is helpful in establishing the diagnosis of first-trimester fetal anemia. Intravasal transfusion can be attempted as early as the first trimester.