Pathological evaluation of uterine leiomyomas treated with gonadotropin-releasing hormone agonist (GnRH-a) therapy: role of mast cells and a possible mechanism of GnRH-a resistance in leiomyomas

Mast Cell Dynamics in the Ovary Are Governed by GnRH and Prolactin

Gonadotrophin releasing hormone (GnRH) facilitates the migration of mast cells (MCs) into the involuting mammary gland. As GnRH is also expressed in the ovary, we examined changes in ovarian MCs. MCs in the ovary were mainly in interstitial tissue and their number increased during the estrous cycle to produce 2 peaks, one at diestrus 2 (20:00 hours) and another at proestrus (17:00 hours). Laser microdissection demonstrated that GnRH mRNA is expressed throughout ovarian tissues (corpora lutea, follicles, and interstitial tissues). GnRH immunoreactivity was also ubiquitous, but MCs were the most strongly immunostained. Analysis of GnRH mRNA in the ovary showed it to fluctuate similarly to the variation in MC number during the estrous cycle, and MCs also expressed GnRH. Local administration of a GnRH agonist (GnRHa) into the hemilateral ovarian bursa increased MCs in the administered ovary. MC number and GnRH mRNA were significantly lowered in the pregnant ovary. Prolactin administration suppressed the normal peaks in MC number in the ovary at both diestrus and proestrus. By contrast, a dopamine agonist, administered when prolactin was elevated during pseudopregnancy, increased ovarian MC number. Furthermore, prolactin inhibited GnRHa-induced peritoneal MC migration in a Transwell assay. These data clearly demonstrate that ovarian MC number is regulated positively by local GnRH expression and negatively by prolactin. The suppressive effect of prolactin on GnRH and MCs would be part of its luteotrophic action.

Markers of Inflammation and Vascular Parameters in Selective Progesterone Receptor Modulator (Ulipristal Acetate)-Treated Uterine Fibroids

The exact mechanism of selective progesterone receptor modulator action in leiomyoma still challenges researchers. The aim of the study was to assess the effects of ulipristal acetate (UPA) on immunoexpression of inflammatory markers and vascularization in fibroids. UPA-treated patients were divided into three groups: (1) good response (≥25% reduction in volume of fibroid), (2) weak response (insignificant volume reduction), (3) and no response to treatment (no decrease or increase in fibroid volume). The percentage of TGFβ, IL6, IL10, CD117, and CD68-positive cells were significantly lower in the group with a good response to treatment vs. the control group. Moreover, the percentage of IL10 and CD68-positive cells in the group with a good response to treatment were also significantly lower compared to the no response group. Additionally, a significant decrease in the percentage of IL10-positive cells was found in the good response group vs. the weak response group. There were no statistical differences in the percentage of TNFα-positive cells and vessel parameters between all compared groups. The results of the study indicate that a good response to UPA treatment may be associated with a decrease of inflammatory markers, but it does not influence myoma vascularization.

Comparison of estrogen receptor-α, progesterone receptor and calponin expression in gonadotrophin-releasing hormone agonist-sensitive and -resistant uterine fibroids

Objective

This study was aimed to compare immunohistochemical expression of estrogen receptor (ER)-α, progesterone receptor (PR), and calponin in gonadotrophin-releasing hormone agonist (GnRH-a)-sensitive and -resistant uterine fibroids.

Methods

We collected data retrospectively. The sensitive group consisted of women who had reduction in uterine volume greater than 40% following GnRH-a treatment. Uterine volume was either reduced by less than 10%, or was increased in the resistant group. A tissue microarray was constructed using formalin-fixed, paraffin-embedded tissues, 31 and 26 patients for the sensitive and resistant groups, respectively. Tissue sections were immunostained with antibodies against ER-α, PR, and calponin. The intensity and area of the immunohistochemical reactions were evaluated using a semi-quantitative scoring system. The Mann-Whitney U-test, Fisher's exact test, and Spearman's rank correlation test were used for analysis of data.

Results

PR (P = 0.04) and calponin (P = 0.03) showed a significantly higher staining intensity in the resistant group than in the sensitive group. Both groups showed comparable expression of ER-α (P = 0.23). In correlation analysis between changes in uterine volume after GnRH-a therapy and clinicopathological factors, the immunohistochemical intensity of PR (P = 0.04) and calponin (P = 0.03) was significantly correlated with changes in uterine volume.

Conclusion

This study shows that GnRH-a resistance of uterine fibroids is not related to ER-α content, but the expression of PR and calponin is related with GnRH-a resistance.