Shorter Anogenital Distance in Women with Ovarian Endometriomas and Adenomyosis, but Not Uterine Leiomyomas

Hypermethylation of Klotho and Peroxisome Proliferator-Activated Receptor γ Concomitant with Overexpression of DNA Methyltransferase 1 in Adenomyosis

Cellular senescence is known to be involved in tissue repair, but its role in adenomyosis remains unclear. This study was tasked to evaluate the expression of Klotho, a well-known aging-suppressing protein, as well as PPARγ and DNMT1 in adenomyotic lesions (AD) in comparison with that of control endometrium (CT). We performed immunohistochemistry analysis of markers of cellular senescence p16 and p21, along with Klotho, PPARγ and DNMT1 in CT and AD samples, followed by the quantification of gene expression of Klotho, PPARγ and DNMT1 in epithelial organoids derived from AD and CT samples and methylation-specific PCR to evaluate promoter methylation status. The effect of forced expression and knockdown of DNMT1 on Klotho and PPARγ expression in ectopic endometrial epithelial cells was evaluated. We found that both p16 and p21 immunoreactivity in AD was significantly higher while that of Klotho and PPARγ was significantly lower than CT samples, which was concomitant with elevated immunoexpression of DNMT1. The results were confirmed by transcriptional analysis using epithelial organoids derived from AD and CT samples. In addition, the promoter regions of both Klotho and PPARγ genes were hypermethylated in AD as compared with CT, and treatment with HDAC and DNMT inhibitors reactivated the expression of both Klotho and PPARγ. Forced expression of DNMT1 resulted in downregulation of both Klotho and PPARγ but its knockdown increased their expression. Thus, overexpression of DNMT1 seems to facilitate the promoter hypermethylation of both Klotho and PPARγ in AD, resulting in their reduced expression that is suggestive of the role of senescence in adenomyosis.

Are Adenomyosis and Endometriosis Phenotypes of the Same Disease Process?

In recent literature reviews, we concluded that the possibility that endometrial molecular aberrations are the sole or a necessary determinant of endometriosis and the Tissue Injury and Repair (TIAR) theory are yet to be convincingly proven. Here, we critically examine the theory that adenomyosis and endometriosis represent different phenotypes of a single disease. A common etiopathology for adenomyosis and endometriosis has been suggested because both conditions entail the presence of endometrial tissue at locations other than the lining of the uterus. There are wide differences in reported disease incidence and prevalence and, consequently, in estimates of the coexistence of both conditions. There are some similarities but also differences in their clinical features and predisposing factors. Each condition has a range of subtypes. These differences alone pose the question of whether subtypes of endometriosis and adenomyosis have different etiopathologies, and, in turn, this raises the question of whether they all share a common etiology. It is debatable whether the recognized differences between the eutopic endometrium in adenomyosis and endometriosis compared to those in unaffected women are the cause or the effect of the disease. The finding of common mutations, particularly of KRAS, lend support to the notion of shared predisposing factors, but this alone is insufficient evidence of causation.