A novel regulatory mechanism network mediated by lncRNA TUG1 that induces the impairment of spiral artery remodeling in Preeclampsia

Preeclampsia (PE) is associated with maternal and fetal perinatal morbidity and mortality, which brings tremendous suffering and imposes an economic burden worldwide. The failure of uterine spiral artery remodeling may be related to the abnormal function of trophoblasts and lead to the occurrence and progression of PE. Aberrant expression of long non-coding RNAs (lncRNAs) is involved in the failure of uterine spiral artery remodeling. However, the regulation of lncRNA expression in PE is poorly characterized. Here, we reported that hypoxia-induced microRNA (miR)-218 inhibited the expression of lncRNA TUG1 by targeting FOXP1. Further RNA sequencing and mechanism analysis revealed that silencing of TUG1 increased the expression of DNA demethylase TET3 and proliferation-related DUSP family, including DUSP2, DUSP4, and DUSP5, via binding to SUV39H1 in the nucleus. Moreover, TUG1 modulated the DUSP family in vitro through a TET3-mediated epigenetic mechanism. Taken together, our results unmask a new regulatory network mediated by TUG1 as an essential determinant of the pathogenesis of PE, which regulates cell growth and possibly the occurrence and development of other diseases.

Elevated Expression of lncRNA MEG3 Induces Endothelial Dysfunction on HUVECs of IVF Born Offspring via Epigenetic Regulation

Cardiovascular dysfunction in children born after in vitro fertilization (IVF) has been of great concern, the potential molecular mechanisms for such long-term outcomes are still unknown. Here, we found that systolic blood pressure was a little higher in IVF born offspring at 2 years old compared to those born after being naturally conceived. Besides, the expression level of maternally expressed gene 3 (MEG3) was higher in human umbilical vein endothelial cells (HUVECs) from IVF offspring than that in spontaneously born offspring. Pearson correlation test showed that MEG3 relative expression is significantly related to the children's blood pressure (Coefficient = 0.429, P = 0.0262). Furthermore, we found decreased expression of endothelial nitric oxide synthase (eNOS) and vascular endothelial growth factor (VEGF) along with elevated expression of endothelial-1(ET1) in HUVECs from IVF offspring, accompanied by lower secretion of nitrite, VEGF, and higher secretion of ET1 in the umbilical cord serum of IVF offspring. Correlation analysis showed MEG3 expression highly correlated with ET1 and Nitrate concentration. With pyrosequencing technology, we found that elevated expression of MEG3 was the result of hypomethylation of the MEG3 promoter. Therefore, our results provide a potential mechanism addressing the high-risk of hypertension in IVF offspring via MEG3 epigenetic regulation.

Hepatic IGF2/H19 Epigenetic Alteration Induced Glucose Intolerance in Gestational Diabetes Mellitus Offspring via FoxO1 Mediation

OBJECTIVE

The offspring of women with gestational diabetes mellitus (GDM) have a high predisposition to developing type 2 diabetes during childhood and adulthood. The aim of the study was to evaluate how GDM exposure in the second half of pregnancy contributes to hepatic glucose intolerance through a mouse model.

METHODS

By creating a GDM mouse model, we tested glucose and insulin tolerance of offspring by intraperitoneal glucose tolerance test (IPGTT), insulin tolerance test (ITT), and pyruvate tolerance test (PTT). In addition, we checked the expression of genes IGF2/H19, FoxO1, and DNMTs in the mouse liver by RT-qPCR. Pyrosequencing was used to detect the methylation status on IGF2/H19 differentially methylated regions (DMRs). In vitro insulin stimulation experiments were performed to evaluate the effect of different insulin concentrations on HepG2 cells. Moreover, we detect the interaction between FoxO1 and DNMT3A by chromatin immunoprecipitation-quantitative PCR (Chip-qPCR) and knock-down experiments on HepG2 cells.

RESULTS

We found that the first generation of GDM offspring (GDM-F1) exhibited impaired glucose tolerance (IGT) and insulin resistance, with males being disproportionately affected. In addition, the expression of imprinted genes IGF2 and H19 was downregulated in the livers of male mice via hypermethylation of IGF2-DMR0 and IGF2-DMR1. Furthermore, increased expression of transcriptional factor FoxO1 was confirmed to regulate DNMT3A expression, which contributed to abnormal methylation of IGF2/H19 DMRs. Notably, different insulin treatments on HepG2 demonstrated those genetic alterations, suggesting that they might be induced by intrauterine hyperinsulinemia.

CONCLUSION

Our results demonstrated that the intrauterine hyperinsulinemia environment has increased hepatic FoxO1 levels and subsequently increased expression of DNMT3A and epigenetic alterations on IGF2/H19 DMRs. These findings provide potential molecular mechanisms responsible for glucose intolerance and insulin resistance in the first male generation of GDM mice.

Fructose levels are elevated in women with polycystic ovary syndrome with obesity and hyperinsulinemia

STUDY QUESTION

Are fructose levels altered in women with polycystic ovary syndrome (PCOS)?

SUMMARY ANSWER

Elevated serum fructose levels are associated with PCOS in Chinese Han women with overweight/obesity and hyperinsulinemia, and fructose levels are higher in follicular fluids from PCOS patients than from control subjects.

WHAT IS KNOWN ALREADY

Both fructose levels and PCOS are closely linked to obesity and insulin resistance. However, the relationship between fructose and PCOS remains largely unknown.

STUDY DESIGN, SIZE, DURATION

A total of 157 Chinese Han women (67 controls and 90 PCOS patients) were recruited at Shengjing Hospital of China Medical University. To systematically study the relationship between serum fructose levels and PCOS, the study population of control subjects and PCOS patients was divided into overweight/obese and lean subgroups, and hyper-fasting serum insulin (FSI) and normal-FSI subgroups, respectively.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Fructose levels were measured in serum samples collected from 80 patients with PCOS (32 lean, 48 overweight/obese) and 59 control subjects (27 lean, 32 overweight/obese) and in follicular fluid samples collected from mature follicles (17-22 mm) and matched immature follicles (8-13 mm) from 10 patients with PCOS and 8 control subjects.

MAIN RESULTS AND THE ROLE OF CHANCE

Serum fructose levels were increased in overweight/obese and hyper-FSI PCOS patients compared with the control subjects. Fructose had an area under the curve (AUC) of 79.7% at a cutoff value of 10.13 pmol/μl, with a sensitivity of 91.7% and a specificity of 59.3% for the prediction of PCOS in overweight/obese patients. In the hyper-FSI group, fructose had an AUC of 72% at a cutoff value of 10.49 pmol/μl, with a sensitivity of 71.1% and a specificity of 64.4% for the prediction of PCOS. There were no differences between fructose, total testosterone, free testosterone or dehydroepiandrosterone sulfate levels with respect to the reliability of predicting PCOS in the overweight/obese or hyper-FSI groups using the method outlined by Hanley and McNeil. Notably, the combination of fructose and total testosterone levels resulted in the highest AUC of 86.0% and high sensitivity (85.4%) and specificity (83.1%) for the prediction of PCOS in overweight/obese patients. The positive predictive value (PPV) and negative predictive value (NPV) were 80.4 and 87.5%, respectively. Similarly, the combination of fructose and total testosterone levels also resulted in a high AUC of 80.2% and moderate sensitivity (73.3%) and high specificity (84.7%) for the prediction of PCOS in hyper-FSI patients. The PPV and NPV were 78.6 and 80.6%, respectively. Furthermore, fructose levels were significantly higher in follicular fluids from PCOS patients than from control subjects, regardless of whether the follicles were mature or immature.

LIMITATIONS, REASONS FOR CAUTION

It remains unclear whether fructose levels contribute directly to follicular development and the pathogenesis of PCOS or are merely a biomarker of these processes.

WIDER IMPLICATIONS OF THE FINDINGS

The results of the present study, together with our previous study, show that monosaccharide status may be a novel marker for PCOS, highlighting the importance of further investigation into the role of monosaccharides, especially fructose, in the pathogenesis of PCOS.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by the National Natural Science Foundation of China (No. 81671423 and No. 81402130), the National Key Research and Development Program of China (No. 2018YFC1003100), Liaoning Provincial Key Research and Development Program (No. 2018225090), the Fok Ying Tung Education Foundation (No. 151039), Distinguished Talent Program of Shengjing Hospital (No. ME76) and Distinguished Teacher Program of China Medical University (No. QGZ2018079). No competing interests were declared.

Second-trimester and third-trimester maternal lipid profiles significantly correlated to LGA and macrosomia

BACKGROUND

According to the theory of fetal-derived adult diseases, abnormal fetal development might affect the occurrence of diseases in adulthood, and appropriate fetal growth status intrauterine might have a beneficial effect on it. To adapt properly for fetal development, there are numerous changes in the maternal physiology during pregnancy, including blood lipid metabolism. The aim of this study is to evaluate the association between lipid profiles in the second and third trimesters of normal pregnancy and fetal birth weight.

MATERIALS AND METHODS

The study population was derived from 5695 pregnant women, who maintained routine prenatal care at the women's hospital of Zhejiang University, School of medicine January 1, 2014, and December 31, 2014. The pregnant women in this study all carried uncomplicated singleton pregnancies to at least 37 weeks.

RESULTS

The mean (standard deviation) birth weight was 3361.00 (385.94) g; 413 (7.3%) of the infants were large for gestational age, and 330 (5.8%) were macrosomia. On multiple linear regression analysis, positive determinants of birth weight were gravidity, parity, gestational age at delivery, male infant, maternal height, and weight before pregnancy, weight gain during pregnancy, fasting blood glucose (FBG) level, second-trimester cholesterol (TC) and third-trimester triglyceride (TG), gestational albumin (ALB), and third-trimester high-density lipoprotein (HDL-C) levels were each negatively associated with birth weight. On logistic regression analysis, the significant metabolic lipid predictors of delivering a large-for-gestational-age infant were second- and third-trimester TG (aOR = 1.178, 95% CI 1.032-1.344, p = 0.015; aOR = 1.106, 95% CI 1.043-1.173, p = 0.001, respectively) and second- and third-trimester HDL-C level (aOR = 0.655, 95% CI 0.491-0.874, p = 0.004; aOR = 0.505, 95% CI 0.391-0.651, p < 0.001, respectively). Third-trimester TG and HDL-C were stable predictors of large-for-gestational-age infants in stratification analysis. High TG and low HDL-C level during third trimester could be considered as indicators of a high risk of large for gestational age (LGA) and macrosomia, regardless of infant gender.

CONCLUSION

These results suggest that future lifestyle programs in women of reproductive age with a focus on lowering TG levels (i.e., diet, weight reduction, and physical activity) may help to reduce the incidence of LGA and macrosomia.

An effective method for trophectoderm biopsy using mechanical blunt dissection: a step-by-step demonstration

OBJECTIVE

To present an effective approach to trophectoderm biopsy for blastocysts of different stages and characteristics by mechanical blunt dissection (MBD).

DESIGN

Stepwise demonstration with still pictures and operational video clips to explain tips and tricks for trophectoderm biopsy. (This demonstration was approved by the Reproductive Study Ethics Committee at Shengjing Hospital of China Medical University.) SETTING: In vitro fertilization laboratory.

PATIENT(S)

Patients who underwent preimplantation genetic testing.

INTERVENTION(S)

The illustrated techniques of blastocyst trophectoderm biopsy using micromanipulation methods include artificial shrinkage, zona pellucida drilling, injecting media from the drilling, aspiration of trophectoderm cells into the biopsy pipette (outer diameter 27 μm for fully expanded blastocysts and peanut-shaped hatching blastocysts; outer diameter 20 μm for 8-shaped hatching and hatched blastocysts), detachment of the trophectoderm cells by laser pulse combined with MBD (performed using the rims of the biopsy and holding pipettes), and release of the biopsy fragment.

MAIN OUTCOME MEASURE(S)

Successful biopsy rate and survival after warming.

RESULT(S)

Our biopsy strategy does not involve assisted hatching on day-3 or day-4 embryos, which can leave the embryo undisturbed in culture up to the expanded blastocyst stage. Notably, this approach demonstrates several noteworthy advantages for sampling blastocysts of different stages and characteristics, and it maintains a desirable successful biopsy rate (95.4%, n = 1,872) and survival rate after warming (100%, n = 440). The MBD method may reduce thermal damage because fewer laser pulses are used, compared with the traditional laser-only biopsy techniques. For noncollapsed blastocysts after artificial shrinkage, the strategy of injecting medium from the zona pellucida drilling helps to separate the trophectoderm cells from the zona pellucida, thus facilitating the biopsy procedure. For peanut-shaped hatching blastocysts, this approach could provide better control over the aspiration of trophectoderm cells into the biopsy pipette. Especially if the inner cell mass is herniating from the zona pellucida, the trophectoderm biopsy can be performed away from the inner cell mass to avoid damaging it. In addition, the MBD approach combined with the biopsy pipette (outer diameter 20 μm) can effectively control the target number of trophectoderm cells, thus simplifying the process of obtaining a biopsy from a hatched blastocyst.

CONCLUSION(S)

Our biopsy approach demonstrates several noteworthy advantages. Considering its benefits and the simplicity of its execution, this systematic biopsy method for blastocysts of different stages and characteristic can be widely applied.

Whole-Exome Sequencing Revealed Mutations of MED12 and EFNB1 in Fetal Agenesis of the Corpus Callosum

Agenesis of the corpus callosum (ACC) is a birth defect in which the corpus callosum is either partially or completely missing. With recent advances in prenatal ultrasound, detection of ACC in obstetric practices is becoming more common. Etiologies of ACC include chromosome errors, genetic factors, prenatal infections, and other factors related to the prenatal environment. In an effort to elucidate more about the genetic influence in the pathogenesis of ACC, we identified, through whole-exome sequencing (WES), two gene mutations in two families with complete agenesis of the corpus callosum. These two mutations are located on chromosome X: one is a hemizygous missense mutation c.3746T>C (p. L1249P) in the gene mediator complex subunit 12 (MED12); the other one is a heterozygous missense mutation c.128+5G>C in gene ephrin B1 (EFNB1). Historically, early diagnosis of complete ACC during pregnancy has been difficult; however, WES has provided us with a creative avenue of diagnosis, combining identification of genetic mutations with prenatal imaging.

Minimally invasive preimplantation genetic testing using blastocyst culture medium

STUDY QUESTION

Is minimally invasive chromosome screening (MICS) using blastocyst culture medium (BCM) sufficiently fast and accurate for preimplantation genetic testing (PGT)

SUMMARY ANSWER

A new assay for MICS, named MICS-Inst achieved high-resolution, comprehensive chromosome ploidy detection using BCM.

WHAT IS KNOWN ALREADY

BCM is a viable source of genomic DNA for use in PGT.

STUDY DESIGN, SIZE, DURATION

Forty-one vitrified blastocysts donated by 22 couples known to carry a chromosome rearrangement and 21 vitrified blastocysts donated from 8 couples with normal karyotypes were used in this study. Good-quality blastocysts, defined as Day 5 and Day 6 embryos ≥ BB (AA, AB, BA, BB) based on the Gardner system were used for analysis. Recruitment took place from May 2018 to August 2018. We performed PGT for structural rearrangements (PGT-SR) on 41 BCM, trophectoderm (TE) biopsy and blastocyst-stage embryo (BE) samples as well as PGT for aneuploidies (PGT-A) on 21 BCM, TE biopsy and BE samples.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We made several significant modifications to the BCM composition (mixing blastocoel fluid and spent blastocyst medium) as well as the pre-existing multiple annealing and looping-based amplification cycles (MALBAC) techniques and library generation procedures. The design of a quasilinear preamplification (Pre-AMP) primer and AMP primers 1 and 2 enables the preparation of a next-generation sequencing library after the exponential amplification stage by introducing the Illumina P5 and P7 primers into the final products, which are then ready for sequencing. Sequencing was performed on the Illumina Hiseq 2500 platform with 2.0 Mb raw reads generated for each sample.

MAIN RESULTS AND THE ROLE OF CHANCE

For PGT-A, BCM and TE biopsy samples showed 90% and 86% clinical concordance with the corresponding BE samples, respectively. In addition, both BCM and TE biopsy samples showed 76% karyotype concordance with the corresponding BE samples. For PGT-SR, we successfully obtained ploidy information for all 23 chromosomes with the exception of any rearrangements involving the Y chromosome. Both BCM and TE biopsy samples showed 100% clinical concordance with the corresponding BE samples in detecting chromosomal rearrangements. BCM and TE biopsy samples showed 90% and 100% karyotype concordance with the corresponding BE samples, respectively. Additionally, no statistically significant differences were detected in the aforementioned values of the BCM and TE biopsy samples in either PGT-A or PGT-SR (P > 0.05). Moreover, we achieved accurate quantification of segmental abnormalities using BCM samples. In addition, MICS-Inst reduced the number of steps required for library preparation through the use of new primer designs, resulting in an overall time reduction of 7.5 h. This time reduction allows for the performance of fresh blastocyst transfers.

LIMITATIONS, REASONS FOR CAUTION

The main limitation is that BE, rather the inner cell mass, was used as the standard to evaluate the chromosome screening results.

WIDER IMPLICATIONS OF THE FINDINGS

These results show that MICS-Inst is effective in procedure and precision for PGT, and that it is possible to achieve fresh blastocyst transfer following PGT. The implications are significant, as these findings may lead to minimally invasive PGT methods in the future.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by the National Natural Science Foundation of China (No. 81671423 and No. 81402130), the National Key Research and Development Program of China (No. 2018YFC1003100), Liaoning Provincial Key Research and Development Program (No. 2018225090), the Fok Ying Tung Education Foundation (No. 151039) and Distinguished Talent Program of Shengjing Hospital (No. ME76). No competing interests declared.

lncRNA HIF1A Antisense RNA 2 Modulates Trophoblast Cell Invasion and Proliferation through Upregulating PHLDA1 Expression

Long noncoding RNAs (lncRNAs) have been reported to be involved in various human diseases, and increasing studies have revealed that lncRNAs can play a vital role in preeclampsia (PE). In our study, lncRNA hypoxia-inducible factor 1 alpha (HIF1A) antisense RNA 2 (HIF1A-AS2) was found to be significantly downregulated in placenta tissues of PE patients by quantitative real-time PCR analysis. Moreover, Cell Counting Kit-8 (CCK-8) assays showed that downregulation of HIF1A-AS2 can impede cell proliferation of HTR-8/SVneo and JAR trophoblasts cells. Ectopic overexpression of HIF1A-AS2 can increase the function of trophoblasts cell migration and invasion in vitro. RNA-sequencing (RNA-seq), RNA immunoprecipitation (RIP), and chromatin immunoprecipitation (ChIP) experiments showed that HIF1A-AS2 can recruit lysine-specific demethylase 1 (LSD1) and epigenetically repress pleckstrin homology-like domain, family A, member 1 (PHLDA1) transcription in human trophoblasts cells. In summary, our findings suggest that downregulated HIF1A-AS2 may play a role in the pathogenesis and progression of PE, and has potential as a novel prognostic marker in PE.

Genetic and epigenetic characteristics in ovarian tissues from polycystic ovary syndrome patients with irregular menstruation resemble those of ovarian cancer

BACKGROUND

Irregular menstruation is clinically associated with an increased risk for ovarian cancer and disease-related mortality. This relationship remains poorly understood, and a mechanism explaining it has yet to be described.

METHODS

Ovarian tissues from women with polycystic ovary syndrome (PCOS) and regular menstruation (n = 10) or irregular menstruation (n = 10) were subjected to DNA methylation sequencing, real-time PCR array, whole-exome sequencing, and bioinformatics analysis.

RESULTS

We demonstrated that ovarian tissue from PCOS patients with irregular menstruation displayed global DNA hypomethylation, as well as hypomethylation at several functionally and oncologically significant regions. Furthermore, we showed that several cancer-related genes were aberrantly expressed in ovarian tissue from patients with irregular menstruation, and that their mRNA and microRNA profiles shared appreciable levels of coincidence with those from ovarian cancer tissue. We identified multiple point mutations in both the BRCA1 and MLH1 genes in patients with irregular menstruation, and predicted the potential pathogenicity of these mutations using bioinformatics analyses.

CONCLUSIONS

Due to the nature of ovarian cancer, it is important to broaden our understanding of the pathogenesis and risk factors of the disease. Herein, we provide the first description of a genetic and epigenetic basis for the clinical relationship between irregular menstruation and an increased risk for ovarian cancer.

Elevated Serum Mannose Levels as a Marker of Polycystic Ovary Syndrome

Background: Recent reports have highlighted the role of monosaccharide biosynthesis in the pathogenesis of polycystic ovary syndrome (PCOS), suggesting that these processes may serve as a biomarker in PCOS. Mannose is the main monosaccharide for protein glycosylation in mammals; however, the correlation between mannose and PCOS remains largely unknown. Materials and Methods: A total of 132 Chinese Han women were recruited at Shengjing Hospital of China Medical University. Mannose levels were measured in serum samples collected from 71 patients with PCOS (29 lean, 42 obese) and 61 control subjects (28 lean, 33 obese). Receiver operating characteristics (ROC) curves were prepared to compare the diagnostic performance of mannose and hormonal parameters, individually or in combination. Multivariate logistic regression analysis was used to assess whether serum mannose levels were associated with PCOS after adjusting for other co-variables. Results: We showed that serum mannose levels were significantly increased in PCOS patients compared with control subjects regardless of obese status, and hyperandrogenic PCOS patients had higher serum mannose levels than normo-androgenic PCOS and control subjects. In addition, serum mannose levels were significantly correlated with serum androgen levels. Mannose had an area under the curve (AUC) of 73% at a cutoff value of 225.79 ng/mL with a sensitivity of 66.2% and specificity of 73.8% for predicting PCOS. There were no differences between mannose, total testosterone, free testosterone, or dehydroepiandrosterone sulfate in the reliability of predicting PCOS using the method outlined by Hanley and McNeil. Combining mannose and total testosterone resulted in a higher AUC of 83.3%, and had moderate sensitivity (78.9%) and specificity (77%) for predicting PCOS. The positive and negative predictive values were 80% and 75.8%, respectively. Multivariate logistic regression revealed that higher serum mannose levels were strongly associated with an increased risk of PCOS (P = 0.016; odds ratio, 5.623; 95% confidence interval, 1.371-23.070). Conclusion: Taken together, substantially elevated serum mannose levels are significantly associated with PCOS, highlighting the importance of further research into the role of mannose in the pathogenesis of PCOS.

Allergic rhinitis, olfactory disorders and secretory IgA

The authors point out the possible relationship between the biochemical and immunological components of nasal mucus in subjects affected by allergic rhinitis and/or olfactory disorders. Fifty seven subjects (33 F, 24 M) aged between 19 and 73 years, (median age 65 SD 14.60) were studied. Twenty seven of them were normosmic affected by allergic rhinitis and taken as control group, (14 were positive to allergometric tests and/or RAST, while the other 13 were negative), 30 were dysosmic, and subdivided into parosmic (n = 6), anosmic (n = 15) and hyposmic (n = 9) (only one was negative both to allergometric tests and to RAST). In all patients we assessed: nasal mucus (it was analysed for: mucus quantity, pH, protein concentration, K+ concentration and the SIgA antibodies, tested both by radian immunodiffusion and by ELISA), allergometric tests, PRIST, RAST, anterior rhinomanometry, evoked olfactory potential. As regard to allergometric tests, we have no observed statistically significant differences between the control and the dysosmic group, although all the dysosmic patients (except one) were positive both to allergometric tests and to RAST. Total (PRIST) and specific (RAST) IgE values (except for the anosmic subjects who had IgE values moderately higher) were similar to the results obtained by allergometric tests. As regards to nasal secretion quantity, it was reduced (p: n.s.), like the pH (p: n.s.), in the parosmic subjects. On the other hand, proteins concentration of nasal secretion was lowered in hyposmic (p: n.s.) and anosmic (p = 0.05) subjects, while there were no differences between parosmic subjects and control group. The values of SIgA in controls and hyposmic subjects were not too different and similar to those observed by other authors; however they were slightly increased in controls affected by allergic rhinitis with positivity both to RAST and/or allergometric tests (p: n.s.), while they were reduced in the parosmic and significantly in the anosmic patients (p < 0.01). On the basis of that data, the authors conclude that, (though related to a limited case reports) being the secretory IgA values inversely proportional to the gravity of olfactory pathology, a their protective role (if the anatomic-functional substratum is efficient), in the pathologies examined, can be easily hypothesized. Besides, that data highlight that their concentration is slightly decreased in those patients affected by allergic rhinitis, without olfactory disorders (p: n.s.).

[Secretory otitis media: current aspects and therapeutic role of adenoidectomy]

The prognostic influence of adenoidectomy on the clinical course of secretory otitis media (S.O.M.) was evaluated in 46 children with abnormal tympanometry, i.e. a flat curve (type B tympanogram) or a middle ear pressure less than 100 mm H2O (type C tympanogram). The children were divided by randomized, blind allocation into one group of 22 subjected to myringotomy with adenoidectomy and another group of 24 subjected to myringotomy without adenoidectomy. All 46 children were followed up by impedance audiometry, pure tone audiometry and otomicroscopy 1, 3, 6 and 15 months after surgery. No significant differences were found between the two groups. Possible pathogenetic mechanisms leading to the development of S.O.M. in the presence of large adenoids are discussed.