Physiology of Upward Transport in the Human Female Genital Tract

Widespread microbial invasion of the chorioamniotic membranes is a consequence and not a cause of intra-amniotic infection

Acute chorioamnionitis is a response to amniotic fluid (AF) infection. However, it remains unclear whether substantial bacterial propagation in the chorioamniotic membranes (CAMs) precedes microbial invasion of the amniotic cavity (MIAC), which is inconsistent with characteristic 'amniotropic neutrophil migration' in acute chorioamnionitis. This study was performed to determine whether CAMs have widespread bacterial infection during MIAC and whether bacteria normally colonize CAMs. AF pellets and CAMs from the following groups were studied: group 1, patients with positive (n=18) or negative (n=22) AF cultures; group 2, patients with or without acute chorioamnionitis in which the amnion and chorion were studied separately (n=60); and group 3, patients at term who underwent a cesarean delivery (n=30). SYTO 9/propidium iodide fluorescent staining and fluorescent in situ hybridization for 16S rRNA were performed. Real-time quantitative PCR for 16S rDNA and PCR for genital mycoplasmas were also conducted. Bacteria were more frequently detected in AF than in CAMs of patients with positive AF culture (100 vs. 33%; P<0.0001). Bacteria were detected more frequently in CAMs as the severity of chorioamnionitis increased (P<0.01). The median 16S rRNA gene copy number in the amnion was significantly greater than in the chorion (group 2; P<0.0001). Bacteria were not detected in CAMs or AF in women at term before labor (group 3). A fraction of patients with chorioamnionitis or MIAC did not have bacteria in CAMs. Collectively, the findings herein indicate that MIAC does not follow widespread infection of CAMs, but precedes it. We propose a model of MIAC: the initial stage is intra-amniotic bacterial invasion through a discrete region of the CAMs, followed by intra-amniotic proliferation, and bacterial invasion of CAMs primarily extends from the amniotic fluid. This study emphasizes the importance of assessing the intra-amniotic compartment for diagnosis and treatment of preterm birth.

Uterine mechanisms of ipsilateral directed spermatozoa transport: Evidence for a contribution of the utero-ovarian countercurrent system

OBJECTIVE

Spermatozoa transport into uterus and fallopian tubes is directed to the side of the dominant follicle and seems to be controlled by the ipsilateral ovary. The objective of this study was to evaluate the temperature in the fallopian tubes as well as the concentrations of estradiol and progesterone in the utero-ovarian veins draining the ipsilateral ovary and compare these to the contralateral side of the uterus.

STUDY DESIGN

A prospective clinical study.

SETTING

Academic-assisted reproductive technology program.

SUBJECTS

Temperature was measured in both oviducts of 10 patients each in the early phase as well as during the late follicular phase during the course of examination of tubal patency and function. Blood samples of the ovarian veins were obtained during hysterectomy in 10 premenopausal patients with regular menstrual cycles. Five of the women were in the early follicular phase and 5 were in the late follicular phase.

RESULTS

Late follicular phase temperature as well as concentrations of estradiol and progesterone were significantly higher in the ipsilateral tube and the utero-ovarian veins draining the ipsilateral ovary as compared to the contralateral side. No such differences were found during the early follicular phase of the cycle.

CONCLUSIONS

These data support our view that the uterus and fallopian tubes during the late follicular phase immediately before ovulation are composed of two functional units with different functional properties acting as a peristaltic pump resulting in increased transport of spermatozoa into the oviduct ipsilateral to the ovary bearing the dominant follicle and that this effect is mediated in part by the utero-ovarian countercurrent system.

Localization of plasma membrane bound NTPDases in the murine reproductive tract

Extracellular nucleotides might influence aspects of the biology of reproduction in that ATP affects smooth muscle contraction, participates in steroidogenesis and spermatogenesis, and also regulates transepithelial transport, as in oviducts. Activation of cellular nucleotide purinergic receptors is influenced by four plasma membrane-bound members of the ectonucleoside triphosphate diphosphohydrolase (E-NTPDase) family, namely NTPDase1, NTPDase2, NTPDase3, and NTPDase8 that differ in their ecto-enzymatic properties. The purpose of this study was to characterize the expression profile of the membrane-bound NTPDases in the murine female and male reproductive tracts by immunological techniques (immunolabelling, Western blotting) and by enzymatic assays, in situ and on tissue homogenates. Other than the expected expression on vascular endothelial and smooth muscle cells, NTPDase1 was also detected in Sertoli cells and interstitial macrophages in testes, in ovarian granulosa cells, and in apical cells from epididymal epithelium. NTPDase2 was largely expressed by cells in the connective tissue; NTPDase3 in secretory epithelia, and finally, NTPDase8 was not detected in any of the tissues studied here. In addition, NTPDase6 was putatively detected in Golgi-phase acrosome vesicles of round spermatids. This descriptive study suggests close regulation of extracellular nucleotide levels in the genital tract by NTPDases that may impact specific biological functions.

The frequency of microbial invasion of the amniotic cavity and histologic chorioamnionitis in women at term with intact membranes in the presence or absence of labor

OBJECTIVE

The amniotic cavity is normally sterile for bacteria. However, experimental evidence indicates that regular uterine contractions exert a suction-like effect whereby vaginal fluid ascends into the uterine cavity with contractions (demonstrated by sonohysterography contrast media). Consequently, this study was conducted to determine whether the presence and progress of labor are associated with an increased risk of microbial invasion of the amniotic cavity (MIAC), intraamniotic inflammation, and histologic chorioamnionitis in women with term pregnancies with intact membranes.

STUDY DESIGN

Amniotic fluid (AF) was obtained from term singleton pregnant women with intact membranes at the time of cesarean delivery. AF was cultured for aerobic and anaerobic bacteria and genital mycoplasmas, and white blood cell (WBC) count was determined. Patients were divided into 3 groups according to the presence or absence of labor and the progress of labor. Nonparametric statistics were used for analysis.

RESULTS

Results included: (1) a total of 884 pregnant women were enrolled and divided into 3 groups: group 1, not in labor (n = 775); group 2, in early labor (cervical dilatation less than 4 cm) (n = 86); and group 3, in active labor (cervical dilatation 4 cm or greater) (n = 23); (2) the frequency of MIAC was 1% (6 of 775) in women not in labor, 3.5% (3 of 86) in patients with early labor, and 13% (3 of 23) in patients with active labor; and (3) the median AF WBC count and the frequency of histologic chorioamnionitis were also higher in the presence of labor than in the absence of labor.

CONCLUSION

We came to the following conclusions: (1) labor is associated with an increased risk of MIAC, a higher median AF WBC count, and histologic chorioamnionitis in term pregnancy with intact membranes; (2) the more advanced the cervical dilatation, the greater the risk of MIAC, a higher median AF WBC count, and histologic chorioamnionitis; and (3) in contrast, fetal inflammation (funisitis) did not increase with the presence of labor or as a function of cervical dilatation. We propose that labor predisposes to MIAC, a higher median AF WBC count, and histologic chorioamnionitis.

Beta-defensin 126 on the surface of macaque sperm mediates attachment of sperm to oviductal epithelia

Beta-defensin 126 (DEFB126) coats the entire surface of macaque sperm until sperm become capacitated, and the removal of DEFB126 from over the head of sperm is required for sperm-zona recognition. Viable sperm collected from cervix and the uterine lumen of mated female macaques had DEFB126 coating the entire surface, suggesting that DEFB126 is retained on sperm en route to the oviduct. DEFB126 plays a major role in attachment of sperm to oviductal epithelial cells (OECs). Following treatment to either remove or alter DEFB126, sperm were coincubated with explants of OECs, which were assessed for sperm binding following rinsing to remove superficially attached sperm. Sperm treated with either 1 mM caffeine + 1 mM dibutyryl cyclic adenosine monophosphate (dbcAMP) (induces capacitation and complete release of DEFB126 from sperm), 2 mM caffeine (removes DEFB126 from over the head and midpiece but does not induce capacitation), anti-DEFB126 immunoglobulin, or neuraminidase (cleaves sialic acid from terminal positions on glycosylation sites of DEFB126) resulted in similar and significant levels of inhibition of sperm-OEC binding. Preincubation of OECs with soluble DEFB126 also resulted in significantly reduced sperm-OEC binding. Furthermore, reduced OEC binding capability of sperm lacking DEFB126 could be restored by addition of soluble DEFB126 to the sperm surface prior to incubation with OECs. Finally, purified DEFB126, infused into oviducts in situ, associated primarily with the apical membranes of secretory-type epithelial cells. In summary, treatments of macaque sperm that result in either removal, masking, or alteration of DEFB126 result in loss of sperm-OEC binding that is independent of changes in sperm motility. DEFB126 may be directly involved in the formation of a reservoir of sperm in the oviduct of macaques.