Body mass index and the diagnosis of endometriosis: Findings from a national data linkage cohort study

The interplay between endometriosis and obesity

Endometriosis, characterized by uterine-like tissue growth outside the uterus, is a complex disorder with significant clinical implications. This review explores how body composition - both low body mass index (BMI) and obesity - modulates endometriosis progression through metabolic, hormonal, and immune-inflammatory pathways. Obesity-driven leptin signaling emerges as a pivotal link, promoting systemic inflammation, angiogenesis, and lesion persistence via Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathways. Shared molecular mechanisms between endometriosis and obesity highlight opportunities for precision medicine and targeted therapies. By addressing leptin-driven pathways and metabolic dysfunction, we introduce innovative strategies, offering novel insights into the improved management of this multifaceted condition.

Association between exposure to perfluoroalkyl substances (PFAS) and endometriosis in the ENDEA case-control study

BACKGROUND

Perfluoroalkyl substances (PFAS) are environmental contaminants present in a wide range of consumer products and frequently detected in drinking water. They have been linked to adverse reproductive health outcomes in women, but there is limited human evidence on the association of PFAS exposure with endometriosis.

OBJECTIVE/AIM

To explore the association between plasma concentrations of several PFAS, considered individually and as a mixture, and the risk of endometriosis in women of childbearing age.

METHODS

Between 2018 and 2020, 42 patients with endometriosis and 90 controls undergoing abdominal surgery were recruited at two public hospitals in Granada, Spain. The presence or absence of endometriosis was ascertained by laparoscopic inspection of the pelvis and biopsy of suspected lesions (histological diagnosis). Concentrations of 10 PFAS were quantified in plasma samples from participants. Unconditional logistic regression was employed to examine associations of individual PFAS and summed concentrations of short (∑SC) and long-chain (∑LC) PFAS with odds of endometriosis, and quantile g-computation was used to assess their mixture effect.

RESULTS

In models adjusted for age, schooling, and parity, perfluorotridecanoic acid (PFTrDA) was associated with higher odds of endometriosis (odds ratio [OR] = 1.74; 95 % CI = 1.11-2.73 per 2-fold increase in plasma concentrations), while marginally significant associations were found for perfluorohexane sulfonate (PFHxS) (OR = 1.45, 95 % CI = 0.94-2.21) and ∑SC PFAS (OR = 1.48; 95 % CI = 0.96-2.30). No associations were found for the remaining PFAS. The PFAS mixture was non-significantly associated with 1.7-fold higher odds of endometriosis (95 % CI = 0.73-3.80), with perfluorononanoic acid (PFNA), PFHxS, and PFTrDA being the major contributors to this effect.

CONCLUSIONS

These findings suggest that exposure to certain PFAS may increase the odds of endometriosis. However, given the modest sample size, further studies are warranted to verify these results.

A Comprehensive Review of Advanced Diagnostic Techniques for Endometriosis: New Approaches to Improving Women's Well-Being

According to the World Health Organization (WHO), endometriosis affects roughly 10% (190 million) of reproductive-age women and girls in the world (2023). The diagnostic challenge in endometriosis lies in the limited value of clinical tools, making it crucial to address diagnostic complexities in patients with suggestive symptoms and inconclusive clinical or imaging findings. Saliva micro ribonucleic acid (miRNA) signature, nanotechnologies, and artificial intelligence (AI) have opened up new perspectives on endometriosis diagnosis. The aim of this article is to review innovations at the intersection of new technology and AI when diagnosing endometriosis. Aberrant epigenetic regulation, such as DNA methylation in endometriotic cells (ECs), is associated with the pathogenesis and development of endometriosis. By leveraging nano-sized sensors, biomarkers specific to endometriosis can be detected with high sensitivity and specificity. A chemotherapeutic agent with an LDL-like nano-emulsion targets rapidly dividing cells in patients with endometriosis. The developed sensor demonstrated effective carbohydrate antigen 19-9 detection within the normal physiological range. Researchers have developed magnetic iron oxide nanoparticles composed of iron oxide. As novel methods continue to emerge at the forefront of endometriosis diagnostic research, it becomes imperative to explore the impact of nanotechnology and AI on the development of innovative diagnostic solutions.

Evidence of Browning and Inflammation Features in Visceral Adipose Tissue of Women with Endometriosis

BACKGROUND

Patients with endometriosis tend to have a low body mass index, suggesting an inverse relationship between body fat and risk of disease. This is supported by evidence that miRNAs differentially expressed in endometriosis induce browning of pre-adipocytes in vitro. Thus, we hypothesize that endometriosis may underlie adipose tissue (AT) dysfunction and browning.

AIMS

Identify inflammation and browning processes in AT collected from endometriosis patients.

METHODS

Visceral and subcutaneous AT samples were obtained during endometriosis (n = 32) or uterine myoma (n = 14; controls) surgery. Blood catecholamines were determined by high-performance liquid chromatography while IL-6 and TGF-β levels were quantified by ELISA. Adipocyte cross-sectional areas were analyzed in H&E-stained sections by computer-assisted morphometry. Macrophages (F4/80; Galectin-3) and browning activation (UCP-1; PGC-1α) in tissues were identified by dual label immunofluorescence. Expression of inflammatory (IL-6; MCP-1; Galectin-3; CD206; TIMP1; TGF-β) and browning-related (UCP-1; PGC-1α; DIO2; CITED1; CIDEA; TMEM26; TBX1; PRDM16; PPAR-γ) molecules in AT were assessed by RT-PCR and Western blotting.

RESULTS

Compared to controls, patients presented smaller adipocytes, especially in VAT, and lower norepinephrine levels. Serum IL-6, but not TGF-β, was increased in patients. UCP-1, PGC-1α, IL-6, and MCP-1 were upregulated in VAT from endometriosis women, which also evidenced a reduction of CD206, relative to controls. However, no differences were found in mRNA expression of IL-6, TIMP1, and TGF-β nor Galectin-3 protein levels. In SAT, protein expression remained unchanged between patients and controls.

CONCLUSIONS

Our findings support an endometriosis' role as a pro-catabolic state along with local signals of VAT browning and inflammation.

The Molecular Link between Obesity and the Endometrial Environment: A Starting Point for Female Infertility

Female infertility constitutes a growing health problem in developing countries and could be associated with several possible causes including reproductive disorders, congenital malformations, infections and hormonal dysfunction. Nonetheless, a series of additional factors can also negatively impact female fertility and are represented by chronic exposure to environmental pollutants, stress, unhealthy lifestyle choices such as cigarette smoking and, among others, obesity. Excess weight is associated with several chronic diseases, and growing evidence demonstrates that it can compromise reproductive physiology due to its influence on endometrial gene expression and receptivity. Thus, the current review of the literature mainly focused on how obesity can impair uterine receptivity, mostly from a molecular point of view throughout the window of implantation (WOI) period at an endometrial level. It was also highlighted that an obesity-related increase in adipose tissue may lead to a modulation in the expression of multiple pathways, which could cause a hostile endometrial environment with a consequent negative impact on the uterine receptivity and the establishment of pregnancy. Thanks to the use of the endometrial receptivity assay (ERA), a specific microarray that studies the expression of a series of genes, it is now possible to evaluate the endometrial status of patients with infertility problems in a more detailed manner. Moreover, female fertility and endometrial receptivity could be affected by endometriosis, a chronic benign gynecological disease, whose cause-and-effect relationship to obesity is still uncertain. Therefore, further investigations would be required to better elucidate these mechanisms that govern embryo implantation and could be potentially useful for the generation of new strategies to overcome implantation failure and improve the pregnancy rates in obese women.

Is the leptin/BMI ratio a reliable biomarker for endometriosis?

Background

The aim of this study was to analyze the concentration of leptin in peritoneal fluid and plasma and to assess their role as potential biomarkers in the diagnosis of endometriosis.

Materials & methods

Leptin adjusted for BMI (leptin/BMI ratio) was measured using surface plasmon resonance imaging (SPRI) biosensors. Patients with suspected endometriosis were included in the study. Plasma was collected from 70 cases, and peritoneal fluid from 67 cases. Based on the presence of endometriosis lesions detected during laparoscopy, patients were divided into a study group and a control group (patients without endometriosis).

Results

Leptin/BMI ratio in plasma did not differ between women with endometriosis and the control group (0.7159 ± 0.259 vs 0.6992 ± 0.273, p= 0,7988). No significant differences were observed in peritoneal leptin/BMI ratio levels in patients with and without endometriosis (0.6206 ± 0.258 vs 0.6215 ± 0.264, p= 0,9896). Plasma and peritoneal leptin/BMI ratios were significantly lower in women with endometriosis - related primary infertility compared to women with endometriosis without primary infertility (0.640 ± 0.502 vs 0.878 ± 0.623, p < 0.05). The difference was observed in case of primary infertility, but not in terms of the secondary one. No significant differences were noted between leptin/BMI ratio in the proliferative phase and the secretory phase (0.716 ± 0.252 vs 0.697 ± 0.288, p= 0,7785).

Conclusion

The results of present study do not support the relevance of leptin concentration determination as a biomarker of the endometriosis. Due to the limited number of samples in the tested group, further studies are needed to confirm its role.

Down-regulation of the FTO gene in follicular fluid of infertile women with ovarian endometriosis

OBJECTIVE

To evaluate FTO concentrations in follicular fluid (FF) of women with ovarian endometriosis (OE) and controls women without OE undergoing in vitro fertilization-embryo transfer (IVF-ET).

METHODS

FTO concentrations in FF were measured in 74 patients (37 in the control group and 37 in the OE group) by ELISA. We measured the expression of FTO in GCs of 40 patients (19 in the control group and 21 in the OE group) by RT-qPCR. The level of m6A in GCs was measured in 20 patients (10 in the control group and 10 in the OE group) by colorimetry.

RESULTS

Compared with the control group, FTO concentrations in FF (6.92 ± 0.44 vs. 5.67 ± 0.40 ng/ml) (p <.05) and FTO mRNA level in GCs of OE group were decreased significantly (p <.05), and the level of m6A was increased (0.21 ± 0.01 vs. 0.17 ± 0.03 ng) (p >.05).

CONCLUSIONS

The FTO concentrations in FF of infertility women with OE are decreased, which may be related to the impaired oocyte quality in endometriosis patients.

Association between urinary concentrations of polycyclic aromatic hydrocarbons and risk of endometriosis in the NHANES 2003-2006

To explore the association between exposure to polycyclic aromatic hydrocarbons (PAHs) and endometriosis risk. Data were obtained from the 2003-2006 National Health and Nutrition Examination Survey database. Urinary concentrations of PAHs were divided into quartiles, and weighted multivariate logistic regression, restricted cubic spline, and subgroup analyses were performed. An extreme gradient boosting (XGBoost) algorithm was used to screen the most important PAHs. After multivariable adjustments, 9-fluorene, 1-phenanthrene, 2-phenanthrene, and 4-phenanthrene exposure were significantly associated with a risk of endometriosis. Specifically, compared with the reference group, the odds ratios (ORs) of endometriosis for the fourth quartile were 3.52 (95% confidence interval (CI): 1.15, 10.77), 3.10 (95% CI: 1.37, 6.97), 4.86 (95% CI: 1.93, 12.21), and 2.67 (95% CI: 1.02, 7.01) for 9-fluorene, 1-phenanthrene, 2-phenanthrene, and 4-phenanthrene, respectively. In terms of continuous exposure, each one-standard-deviation increase in the urinary concentration of 9-fluorene, 1-phenanthrene, 2-phenanthrene, and 4-phenanthrene was independently associated with a 66% (OR: 1.66, 95% CI: 1.15, 2.40), 62% (OR:1.62, 95% CI: 1.19, 2.20), 68% (OR: 1.68, 95% CI: 1.24, 2.28), and 56% (OR: 1.56, 95% CI: 1.11, 2.19) increase in the risk of endometriosis, respectively, in the fully adjusted model. A significant association between the urinary concentration of 9-fluorene and the risk of endometriosis was also observed in participants who had a high body-mass index (≥25 kg/m2), with a corresponding OR of 2.61 (95% CI: 1.37, 5.00; P for interaction = 0.006). Our findings show that high urinary concentrations of PAHs were associated with a high risk of endometriosis in participants and that the urinary concentration of 9-fluorene was related with a high susceptibility of endometriosis in participants with overweight.

An insight into gut microbiota and metabolites in the mice with adenomyosis

Background

Adenomyosis (AM) is a benign uterine disease characterized pathologically by the invasion of endometrial tissue into the myometrium. The pathogenesis of AM is still far from clear. Although the gut microbiome and metabolomics are thought to contribute to a variety of diseases, the role of them in AM has not been revealed.

Objective

To investigate changes in the gut microbiota and derived metabolites in AM mice.

Method

Female ICR mice were randomly assigned to AM and control groups, and pituitary transplantation was employed to perform AM modeling. Then, the fecal samples were obtained for microbial (16S rRNA gene sequencing) and metabolomic (liquid chromatography mass spectrometry, LC-MS) analysis.

Result

The results of gut microbiota analysis showed that the intestinal microbiota composition of AM mice was altered. The ratio of Firmicutes/Bacteroidetes and the relative abundance of Lactobacillus in AM group increased compared with the control group. Sixty differential expressed metabolites were identified in intestinal metabolites, mainly involved in steroid hormone biosynthesis, cysteine and methionine metabolism, and alanine, aspartate, and glutamate metabolism. Further, correlation analysis verified that L-methionine and L-cystine were negatively correlated with Bacteroides and positively correlated with Desulfovibrio. The Pregnenolone, Androsterone glucuronide, and Testosterone glucuronide were negatively correlated with Unidentified_Ruminococcaceae and Alistipes, whereas they positively correlated with Bacteroides.

Conclusion

AM mice have a unique gut microbiome and intestinal metabolites.

Height and pelvic lesion number: Do they have a positive relationship with postoperative recurrence in adolescent endometriosis?-A retrospective clinical analysis of 89 adolescent endometriosis in China

BACKGROUND

Adolescent endometriosis is a special type of endometriosis. Its diagnosis is often delayed. This study aimed to share the treatment experience of adolescent endometriosis and analyze the clinical manifestation, clinical stage, and risk factors of postoperative recurrence in China.

METHODS

Eighty-nine cases of adolescent endometriosis over 7 years in a single institution were reviewed. Demographic, clinical outcome measures were collected.

RESULT

The cumulative incidence rates of postoperative recurrence at years 1, 2, 3, 4, and 5 were 13.2%, 15.09%, 16.98%, 20.75%, and 20.75%, respectively. The risk factors associated with postoperative recurrence were disease stage, number of lesions, and height. In multivariate analysis, the independent risk factors of postoperative recurrence were height (RR: 1.132, 95% CI: 1.018-1.260) and the number of pelvic lesions (three or more, RR: 4.202, 95% CI: 1.013-17.433).

CONCLUSION

Taller patients and those who had multiple lesion sites (≥3) should receive more attention, because they have a higher possibility of relapse after surgery than their counterparts. This finding can guide the postoperative treatment of adolescent patients with endometrioma.