Biomarker Validation of a New Case Definition of Menstrual Cycle-Associated Syndrome (MCAS) Opinion Paper

There are different case definitions of premenstrual syndrome, one proposed by the American College of Obstetricians and Gynecologists (ACOG) and another based on the Daily Record of Severity of Problems (DRSP) scores. Here we review our recent findings indicating that the gold-standard methods to assess PMS, including ACOG, provide a high degree of false-negative findings. We propose a new case definition of the Menstrual Cycle-Associated Syndrome (MCAS), which is characterized by increased DRSP scores during the menstrual cycle and symptom that increases the week prior to the menses. The MCAS case definition was externally validated by diverse biomarkers including plasma levels of progesterone and estradiol, chemokines (e.g. CCL2, CCL5 and CCL11), epidermal growth factor, hydroperoxides, paraoxonase 1 activity and complement C4. These biomarkers as well as IgA responses to Gram-negative bacteria are significantly associated with the DRSP and its subdomains including depression, anxiety, and physiosomatic symptoms(fatigue, pain). In conclusion, we propose, a) to use the MCAS diagnosis as an indicant of menstrual cycle-related symptoms; and b) to examine the associations of the time series in the DRSP and its subdomains and those in biomarkers including distributed lag models. Aberrations in the uterine-chemokine-brain-axis underpin the pathophysiology of MCAS whereby suboptimal pre-ovulatory follicular development coupled with a relative corpus luteum insufficiency may drive increased chemokine production, lowered antioxidant defenses, neuro-oxidative stress pathways, and increased bacterial translocation. As such, we have delineated new drug targets for the treatment of MCAS. This opinion paper reviews new possible treatments that should be trialed in MCAS.