Long-acting progestin-only contraceptives enhance human endometrial stromal cell expressed neuronal pentraxin-1 and reactive oxygen species to promote endothelial cell apoptosis.

CONTEXT: Despite the absence of progesterone receptor protein in human endometrial endothelial cells (HEECs), endometria of women receiving long-acting progestin-only contraceptives (LAPCs) display reduced uterine blood flow, elevated reactive oxygen species generation, increased angiogenesis, and irregularly distributed, enlarged, fragile microvessels resulting in abnormal uterine bleeding. OBJECTIVE: We propose that paracrine factors from LAPC-treated human endometrial stromal cells (HESCs) impair HEEC functions by shifting the balance between HEEC viability and death in favor of the latter. DESIGN AND SETTING: Proliferation, apoptosis, and transcriptome analyses were performed in HEECs treated with conditioned medium supernatant (CMS) derived from HESCs treated with estradiol (E2) ± medroxyprogesterone acetate or etonogestrel under normoxia or hypoxia. Mass spectrometry interrogated the CMS secretome while immunostaining for neuronal pentraxin-1 (NPTX1), cleaved caspase-3, and cytochrome c was performed in cultured HEECs and paired endometria from women using LAPCs. MAIN OUTCOME: HEEC apoptosis and its underlying mechanism. RESULTS: HESC CMS from E2 + medroxyprogesterone acetate or E2 + etonogestrel incubations under hypoxia induced HEEC apoptosis (P < .05), whereas mass spectrometry of the CMS revealed increased NPTX1 secretion (P < .05). Endothelial cleaved caspase-3 and stromal NPTX1 immunoreactivity were significantly higher in LAPC-treated endometria (P < .001). Transcriptomics revealed AKT signaling inhibition and mitochondrial dysfunction in HEECs incubated with HESC CMS. In vitro analyses proved that CMS decreased HEEC AKT phosphorylation (P < .05) and that recombinant NPTX1 (P < .05) or NPTX1 + H2O2 (P < .001) increase HEEC apoptosis and cytosolic cytochrome c levels. CONCLUSIONS: LAPC-enhanced NPTX1 secretion and reactive oxygen species generation in HESCs impair HEEC survival resulting in a loss in vascular integrity, demonstrating a novel paracrine mechanism to explain LAPC-induced abnormal uterine bleeding.

Molecular analysis of beta-thalassemia and sickle cell anemia in Antalya.

We have studied 918 chromosomes for mutations leading to beta-thalassemia and sickle cell anemia, which are the two most frequently found monogenic disorders in Antalya, Turkey. Three hundred and seventy-seven postnatal and 82 prenatal cases were studied between 2000 and May 2003 in our center using reverse dot blot hybridization (RDBH) with 22 probes specific for Mediterranean populations. In this study, IVSI-110 (G-->A) appeared to be the most common mutation with an occurrence rate of 44.4% among the 16 different mutations found to be associated with beta-thalassemia. Heterozygosity for IVSI-110 was the most prevalent combination, whereas 34 of our 377 postnatal cases showed homozygosity for this mutation, a genotype leading to beta-thalassemia major. The total percentage of postnatal patients clinically diagnosed as beta-thalassemia major was 18.6%, whereas 5% of the cases were diagnosed clinically as beta-thalassemia intermedia. One new Hb variant, Hb Antalya, and one new mutation, Cod 3 (+T) were found. HbS accounted for 10.3% of all mutations; homozygosity was found in 1.9% of all cases. Of the 82 cases analysed prenatally for beta-globin gene mutations and by cytogenetic techniques for possible chromosomal abnormalities, 21 fetuses were found to be affected with beta-globin gene mutations. One of these fetuses was also found to have a 45,X karyotype, and 1 had a 46,XY/47,XY,+22 karyotype. Quite a high rate of consanguineous marriages in Antalya (35.17%) renders mutation screening, genetic counseling, and educational programs held by our Thalassemia Unit essential. This study was the first to be performed specifically in our region where hemoglobinopathies are most frequent as a consequence of migrations of racially and culturally distinct groups to the area in the distant past.

Regulation of Fas ligand expression by vascular endothelial growth factor in endometrial stromal cells in vitro.

When Fas ligand (FasL) interacts with the Fas receptor, it induces apoptosis through autocrine and/or paracrine signalling. Vascular endothelial growth factor (VEGF) is a potent mitogenic cytokine. VEGF plays a role during remodelling of the endometrium following menstruation. We hypothesized that, by regulating FasL expression, VEGF may play a role in endometrial stromal cell survival by decreasing autocrine apoptotic signalling. We aimed to determine the expression of FasL in cultured endometrial stromal cells and its modulation by VEGF. VEGF induced a decrease in both FasL-positive cell number and FasL intensity as determined by immunocytochemistry and western blot respectively (P < 0.05). These effects of VEGF were observed in a concentration-dependent manner (10-42%; P < 0.05). Anti-VEGF neutralizing antibody alone resulted in an increase in the FasL expression. When combined with VEGF, anti-VEGF reversed the VEGF-induced decrease in FasL level up to 100% (P < 0.05). In addition, western blot analysis showed that FasL expression in endometrial stromal cells demonstrated a cyclic change every 12 h during 48 h of incubation. These results suggest that down-regulation of FasL by VEGF may affect endometrial stromal cell survival in an autocrine or paracrine manner. The decrease in FasL level may be due to a stimulation of its degradation. Our results show that FasL in endometrial stromal cells in culture has a cyclic expression model, suggesting that there may be a regulation at the translation level.

Endocrine-immune interactions in human endometrium.

The immune system is a complex entity designed to eliminate foreign intruding antigens and is influenced by and, in turn, influences the function of the reproductive system. Despite the widespread associations between immunology and reproductive medicine, the study of system interactions remains in its infancy. Many diverse facts are accumulating, and pieces of the puzzle are becoming available to provide a clearer picture. In this review article, we focus on the interactions between endocrine and immune systems in the human endometrium. Understanding the molecular pathways in endocrine-immune interactions in the human endometrium is crucial to understand events such as menstrual bleeding, tissue repair and regeneration, inflammation, angiogenesis, blastocyst implantation, and progression of pregnancy. These events require a balanced regulation of endometrial differentiation, proliferation, cell survival, leukocyte recruitment, apoptosis, and angiogenesis by sex steroids. In this review, we first outline the role of survival factors such as phosphoinositol 3-kinase/protein kinase B, PTEN, NFkappaB, and apoptotic molecules (Fas-FasL, Bcl-2). We then discuss their regulation by estrogen and progesterone in the endometrium. We present evidence for direct and/or indirect roles of steroid hormones on the expression of chemotactic cytokines (interleukin-8 and monocyte chemotactic protein-1) and on the survival versus apoptosis of resident endometrial cells (stromal, epithelial, and endothelial cells) and nonresident cells (leukocytes).