**6. Endometriosis and Fallopian tube function**

Women with endometriosis have an increased incidence of tubal ectopic pregnancy, suggesting that endometriosis results in impairment of tubal transport of gametes and embryos. Previous *in vitro* studies have revealed that peritoneal fluid collected from women with endometriosis caused a decrease in the Fallopian tube ciliary beat frequency (Lyons *et al.,* 2006), which supports the increased incidence of implantation of the embryo within the Fallopian tubes of these women. The pelvic inflammation associated with endometriosis can also cause adhesion and scar tissue formation within the Fallopian tubes creating a physical obstruction to embryo transport (Halis & Arici 2004). The pathogenesis of endometriosis involves changes both in cellular and in humoral immunity. Impaired natural killer cell activity results in inadequate removal of debris following retrograde menstruation. Elevated primary inflammatory mediators, which are characterised by increased numbers of macrophages, result in the production of secondary inflammatory mediators such as cytokines, chemokines and growth factors (Harada *et al.,* 2001) However, the secretion of primary inflammatory mediators can also be induced by microbial stimuli (Wira *et al.,* 2005). This highlights the relevance of a non-sterile endometrium in this aetiology. It may be that the retrograde menstruation of colonised or contaminated (by microorganisms) menstrual blood enhances the pathology of endometriosis by recruiting macrophages, which then secrete elevated levels of pro-inflammatory cytokines.

A small study investigating eutopic and ectopic endometrium, identified DNA with a 96% homology to the Gram-negative bacterium *Shigella* spp. in ectopic but not in eutopic endometrium. Therefore, an infection hypothesis was proposed for the pathogenesis of endometriosis (Kodati *et al.,* 2008). Recently, Khan *et al.,*. (Khan *et al.,* 2010) reported a significant increase in the number of colony forming units of *E*. *coli* recovered from the menstrual blood of women with endometriosis when compared to women without the disease. In their study, the bacterial endotoxin concentration was also higher both in the menstrual blood and in the peritoneal fluid samples from women with endometriosis. The relative level of *E*. *coli* within the peritoneal fluid of women with endometriosis was likely due to retrograde menstruation through the Fallopian tubes and into the pelvic cavity. The 'open' nature of the female genital tract makes it unlikely that secretions from the uterus, Fallopian tubes and peritoneal cavity remain compartmentalised. Transport of microorganisms within the upper genital tract may well be an area requiring further investigation in the pathogenesis of endometriosis and its increased association with tubal ectopic pregnancy.

Interestingly, *E*. *coli* has also been cultured from tubo-ovarian abscesses in women with ovarian endometriomas and pelvic endometriosis (Kavoussi *et al.,* 2006; Lin *et al.,* 2010).The fluid-filled ovarian endometrioma may provide an excellent growth medium for

Tubal Damage, Infertility and Tubal Ectopic Pregnancy:

have profound effects on fertility in women.

*Immunol*., 130 (3): 347-54

Chlamydia trachomatis. *Int J STD AIDS* 19:283

ectopic pregnancy. *Fertil Steril.* 94(3):833-40.

**8. Conclusions** 

**9. References** 

*Chlamydia trachomatis* and Other Microbial Aetiologies 31

there was no relationship between the ectopic pregnancy rate and the ovarian hyperstimulation protocol used for ovulation induction (Dubuisson *et al.,* 1991). This is despite some studies suggesting that the hormonal protocols used in IVF contribute to

The ectopic pregnancy rate for women having IVF with natural and stimulated cycles was around 11% (Dubuisson et al., 1991), this is consistent with previous reports (Yovich *et al.,* 1985) indicating that in infertile women undergoing IVF and embryo transfer, the rate of tubal ectopic pregnancy is significantly higher compared to women conceiving naturally.

Infectious agents can damage biological functions of the female reproductive tract with devastating consequences. Among the most common microorganisms involved in sexually transmitted infections and interfering with female fertility are *C*. *trachomatis* and *N*. *gonorrhoeae*. These two pathogens are involved in damage to the cervix, Fallopian tubes and tubal luminal architecture in infected women. Tubo-peritoneal damage seems to be the leading cause of microbial interference with human fertility. *C. trachomatis* is considered the most important cause of tubal obstruction and PID. Screening for repeat chlamydial infections using randomised control trials and prevalence of *Chlamydia* rather than PID as an end point should provide information useful for controlling morbidity associated with these infections. Infection of the female genital tract with other bacterial organisms including *M*. *genitalium,* Ureaplasma spp., anaerobes and aerobes/microaerophiles can also affect the precise functioning of components of this site resulting in tubal occlusion and infertility. Bacterial vaginosis is strongly linked to tubal infertility as causative agents can produce ascending infections of the female upper genital tract. The role of bacterial infections particularly those caused by *C*. *trachomatis* and immune responses to these infections as causes of damage to sperm function require further investigation. Finally, continued efforts in vaccine development to control *C. trachomatis* genital infections would seem prudent to prevent sequelae of unresolved or untreated infections of the female genital tract that can

Aghaizu A, Atherton H, Mallinson H, Simms I, Kerry S, Oakeshott P, Hay PE. 2008.

Agrawal, T., Gupta, R., Dutta, R. Srivastava, P.,Bhengraj, A. R., Salha, S. and Mittal, A.,

Al-Azemi M, Refaat B, Amer S, Ola B, Chapman N, W. L. 2010. The expression of inducible

Alpay Z, Saed GM, Diamond MP. 2006. Female infertility and free radicals: potential role in

adhesions and endometriosis. *J Soc Gynecol Investig* 13:390-8

Incidence of pelvic inflammatory disease in untreated women infected with

(2009) Protective or pathogenic immune response to genital chlamydial infection in women--a possible role of cytokine secretion profile of cervical mucosal cells. *Clin* 

nitric oxide synthase in the human fallopian tube during the menstrual cycle and in

ectopic pregnancy possibly by alterations in tubal muscle contractions or ciliary beat.

microorganisms, and endometriomas have been identified as a risk factor for tubo-ovarian abscess formation (Kubota *et al.,* 1997; Lin *et al.,* 2010). Women with endometriosis appear to represent a population at increased risk of infection and subsequent tubo-ovarian abscess due to an altered local immune environment (Chen *et al.,* 2004; Lebovic *et al.,* 2001). The risk of endometriosis is also increased in women with shorter menstrual cycles and an increased menstrual flow (Halme *et al.,* 1984). Again, the retrograde menstruation of non-sterile menstrual blood into the peritoneal cavity provides a route for microbial transport. The menstrual debris may also promote continued survival and persistence of these microorganisms in the upper genital tract. Microorganisms have been detected in the endometrium of 83% of women during the post-partum period (Andrews *et al.,* 2005). However, both vaginal and endocervical cultures demonstrated low concordance with endometrial cultures (Cicinelli *et al.,* 2009). This may suggest that tropisms exist in the genital tract that can modulate microbial survival. In studies investigating women with chronic endometritis, Cicinelli *et al.,*. (Cicinelli *et al.,* 2008) reported isolation aerobic bacteria in over 73% of cases in symptomatic women but in only 5% of women without clinical evidence of endometritis. A shortcoming if their study was that they did not screen endometrial samples for the presence of anaerobes, which dominate the genital microflora. Together, these studies suggest that the endometrial cavity is not sterile, and that the presence of microorganisms does not necessarily result on overt inflammation. The possibility exists that in women with endometriosis, who have an impaired genital tract immune response, that (1) these microorganisms may replicate causing increased pathology, including tubal damage and (2) the microflora represent a stimulus for the enhanced chemotaxis of macrophages and the subsequent secretion of secondary inflammatory mediators identified in this condition.

Other chemical mediators have also been investigated in women with endometriosis. Inducible nitric oxide synthase, activated by cytokines and growth factors (Morris and Billiard, 1994; Nussler and Billiar, 1993), regulates embryo transport within the Fallopian tube. What is interesting is that in women with endometriosis and PID, nitric oxide levels are increased (Alpay *et al.,* 2006; Bouyer *et al.,* 2002; Sioutas *et al.,* 2008). Lipopolysaccharide was capable of *in vitro* activation of macrophages in the peritoneal fluid of women with endometriosis, increasing inducible nitric oxide synthase and nitric oxide production in these women but not in women without disease (Osborn *et al.,* 2002). If endometriosis is part of an infectious condition, then these results may be evidence of the activity f polarised macrophages in this population. A macromolecular ovum capture inhibitor, causing formation of a membrane over the fimbrial cilia, has been also detected in the peritoneal fluid from women with endometriosis (Suginami & Yano 1988).

Studies investigating ectopic pregnancy following IVF are limited however, it has been suggested that the hormonal stimulation protocol and the infertility history may also be mechanisms predisposing women to ectopic pregnancy (Chang & Suh 2010).

### **7. IVF**

Hydrosalpinx is associated with decreased IVF success (Wainer *et al.,* 1997). Approximately 30% of women undergoing IVF for tubal factor infertility have hydrosalpinges (Blazar *et al.,* 1997; Murray 1997). The incidence of ectopic pregnancy was significantly higher in patients having IVF treatment for tubal factor infertility than in those diagnosed with infertility die to endometriosis or idiopathic infertility (Dubuisson *et al.,* 1991). It has been reported that there was no relationship between the ectopic pregnancy rate and the ovarian hyperstimulation protocol used for ovulation induction (Dubuisson *et al.,* 1991). This is despite some studies suggesting that the hormonal protocols used in IVF contribute to ectopic pregnancy possibly by alterations in tubal muscle contractions or ciliary beat.

The ectopic pregnancy rate for women having IVF with natural and stimulated cycles was around 11% (Dubuisson et al., 1991), this is consistent with previous reports (Yovich *et al.,* 1985) indicating that in infertile women undergoing IVF and embryo transfer, the rate of tubal ectopic pregnancy is significantly higher compared to women conceiving naturally.
