Chapters authored
The Link between Environmental Toxicant Exposure and Endometriosis Re-Examined
Endometriosis is widely acknowledged to be an estrogen dependent disease or unknown etiology. Recognition that environmental toxicants can bind with and activate the estrogen receptor, dysregulate steroid metabolism and, in some cases, act as anti-androgenic substances (phthalate esters) has led to proposal that exposure to environmental toxicants are associated with increased risk of endometriosis. Since our last review of the subject in 2008, the literature has expanded with several epidemiological and biomonitoring studies suggesting a potential association, whereas others have been unable to demonstrate a link between exposure and enhanced risk. Therefore, we carried out a systematic review and critical appraisal of the literature published over the past decade (2009–2019). The majority of studies found dealt with exposure to polychlorinated biphenyls (PCBs), dioxins, dioxin-like and non-dioxin-like compounds, bisphenol A and phthalate esters. Several studies suggest a potential association between exposure to environmental toxicants; however, important weaknesses in study design, methodology, and analysis together with many contradictory studies weaken confidence in these associations. Consequently, we conclude that despite a growing literature, evidence for an association between exposure to environmental toxicants and risk of endometriosis remains weak.
Part of the book: Endometriosis
microRNA and Overcoming the Challenges of Their Use in the Diagnosis of Endometriosis
Endometriosis is a common estrogen dependent and inflammatory disease affecting approximately 176 million women worldwide. Currently, the time between onset of symptoms and a definitive diagnosis has been reported by several international studies to range from 6 to 12 years. Presently, laparoscopic surgery followed by histopathological confirmation of lesions remains the gold standard for diagnosis. In part because of cost and invasiveness, current trends favor reduced laparoscopic surgeries in preference of the non-surgical diagnosis of endometriosis. However, the search for a clinical marker or markers of endometriosis that provide equal or similar sensitivity and specificity to laparoscopy has remained elusive. Thus, the search for a diagnostic test for the diagnosis of endometriosis continues to be a high priority research and clinical issue. Recent studies have reported favorable results with microRNA; however, lack of replication and absence of validation suggest that circulating miRNA may not be reliable for clinical use. Use of different screening platforms together with divergent methods may account for some of the lack or reproducibility in the literature. Herein we critically assess the recent literature and explore sources for discrepant findings. We suggest that prospective studies using validated reference miRNA to normalize results together with improved study design may yet reveal a suitable diagnostic marker or panel of markers for the diagnosis of endometriosis.
Part of the book: Endometriosis