Endometriosis diagnostics : meta-analysis implementation to develop a conceivable protocol for early detection : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Physiology at Massey University, Palmerston North, New Zealand
Background: Endometriosis is a common gynaecological condition affecting at least 10% of women globally. It is a common cause for infertility in women and can be asymptomatic. This condition can also cause chronic pain and include symptoms such as dysuria, dysmenorrhea, fatigue, and nausea. Currently, invasive laparoscopy is the gold standard for diagnosis. Endometriosis occurs when endometrial stem cells (EnSCs) invade the body, implant and grow into ectopic lesions. These lesions can be found in many areas of the body including the peritoneal cavity, lungs, and the brain. There are currently four theories surrounding the process of endometriosis: retrograde menstruation, lymphovascular metastasis, embryonic rest, and coelomic metaplasia. Objectives: The main objective of this analysis was to discover a novel method to diagnose endometriosis at the earliest possible stage that could be used as a new gold standard procedure. Methods: Primarily, reviewing the growth, structure, and function of the endometrium was necessary to investigate how EnSCs can migrate to various areas of the body, attach, and grow into painful ectopic lesions. Following this, a PRISMA compliant random-effects meta-analysis was performed on 21 studies of peritoneal fluid (PF) of TNF-α, a cytokine that changes concentrations in the menstrual cycle, and could therefore possess potential differences in endometriosis patients as well. Finally, a study protocol was developed that could validate an early stage endometriosis diagnostics procedure for future implementation. Results: The meta-analysis of PF TNF-α yielded a significant difference (p<0.05). Although this study could not account for menstrual cycle stages, it has displayed support that protein concentration differences exist between endometriotic and non-endometriotic patients. Therefore, further analyses could be performed on different proteins in PF or serum to discover diagnostic candidates for endometriosis. This further supports the ideas described in the Study Protocol that possess the potential for implementation into diagnostic procedures. Conclusions: There appear to be enough studies within the literature to perform similar PRISMA compliant random-effects meta-analyses of various endometriosis associated proteins. When these analyses are performed, the proteins with significant differences will be revealed and their potential explored further for diagnostic implementation.