Trichomonas vaginalis and cervical epithelial changes

Trichomonas vaginalis infection and risk of cervical neoplasia: A systematic review and meta-analysis

OBJECTIVES

The evidence in the literature regarding the relationship between Trichomonas vaginalis (TV) infection and cervical neoplasia is conflicting. The main aim of this study was to evaluate the magnitude of the risk of cervical neoplasia associated with TV infection.

METHODS

A meta-analysis of observational studies, which provided raw data on the association of TV infection with cervical neoplasia, was performed. For this aim, we searched scientific databases (PubMed/Medline, Scopus, the Web of Sciences, and Embase) from inception to March 15, 2023. A random-effects model was applied by Stata 17.0 to calculate the pooled and adjusted odds ratios (ORs) with 95% confidence intervals (CI), including subgroup, sensitivity, and cumulative analyses to explore sources of heterogeneity.

RESULTS

Of the 2584 records initially identified, 35 eligible studies contributed data for 67,856 women with cervical neoplasia, and 933,697 healthy controls from 14 countries were included. The pooled (2.15; 1.61-2.87; I2 = 87.7%) and adjusted (2.17; 1.82-2.60; I2 = 31.27%) ORs indicated a significant positive association between TV infection and the development of cervical neoplasia. There was no significant change in pooled and adjusted ORs by applying sensitivity and cumulative analyses, indicating the robustness of our findings. The pooled OR was significant in most sub-group analyses. There was no publication bias in the included studies.

CONCLUSION

Our findings indicated that women with a TV infection are at significantly greater risk of cervical neoplasia. Future research, particularly longitudinal and experimental studies, should be done to better understand the various aspects of this association.

Association between high risk human papillomavirus infection and co-infection with Candida spp. and Trichomonas vaginalis in women with cervical premalignant and malignant lesions

BACKGROUND

Human papillomavirus (HPV) is the necessary cause of cervical cancer. Cervico-vaginal infection with pathogens like Chlamydia is a likely cofactor. The interactions between HPV, Trichomonas vaginalis (TV) and Candida spp. are less understood, though inflammation induced by these pathogens has been demonstrated to facilitate oncogenesis.

OBJECTIVE

Our study aimed to evaluate the association between Candida spp. and TV co-infection with HPV in cervical oncogenesis.

STUDY DESIGN

Women with normal cervix who were high-risk HPV-negative (N=104) and HPV-positive (N=105); women with CIN 1 (N=106) and CIN 2/CIN 3 (N=62) were recruited from a community based cervical cancer screening program. Cervical cancer patients (N=106) were recruited from a tertiary care oncology clinic. High-risk HPV was detected by Hybrid Capture II technique; Candida spp. and TV were detected by culturing the high vaginal swabs followed by microscopic examination in all. The disease status was established by histopathology in all the women.

RESULT

HPV-positive women had significantly higher risk of having precursor lesions (of any grade) and cancer compared to HPV-negative women. Candida spp. or TV infection did not alter the risk of low grade or high grade lesions among HPV- positive women. HPV positive women co-infected with TV had higher risk of cervical cancer but not those co-infected with Candida spp.

CONCLUSION

The higher risk of cancer observed in the women co-infected with HPV and TV without any enhanced risk of CIN 3 suggests secondary infection of the malignant growth by TV rather than any causal role. Co-infection with Candida spp. and/or TV infection did not increase the carcinogenic effect of HPV on cervix.

Association of Genital Infections Other Than Human Papillomavirus with Pre-Invasive and Invasive Cervical Neoplasia

Human papillomavirus (HPV) is a well-established causative agent of malignancy of the female genital tract and a common Sexually Transmitted Infection. The probable co-factors that prevent spontaneous clearance of HPV and progression to neoplasia are genital tract infections from organisms like Chlamydia, Trichomonas vaginalis etc, smoking, nutritional deficiencies and multiparity. Inflammatory conditions can lead to pre-neoplastic manifestations in the cervical epithelium; however their specific role in cervical carcinogenesis is not yet established. Therefore it is imperative to study the likely association between HPV and co-infection with various common pathogens in the genital tract of women having cervical precancer or cancer. A "Pubmed" search was made for articles in Literature on this topic using the words: Cervical neoplasia, HPV, co-infections, Cervical Intraepithelial Neoplasia (CIN), Trichomonas vaginalis, Candida, Chlamydia and the relevant information obtained was used to draft the review.

Epidemiology of trichomonas vaginalis. A prospective study in China

BACKGROUND AND OBJECTIVES

Trichomonas vaginalis infection is probably one of the most common sexually transmitted diseases. The epidemiology of this disease has long been ignored, and not much is known about its natural history and risk factors.

GOALS

The authors conducted this study to define the incidence rates of T. vaginalis infection and to investigate risk factors for the infection.

STUDY DESIGN

A prospective study was carried out on a cohort of 16,797 women followed up from 1974 to 1985 within the framework of a cervical screening program in Jingan, China. Personal interviews were conducted by trained interviewers.

RESULTS

A total of 1489 new cases of T. vaginalis infection were diagnosed with 132,946 person-years of observation. In a multivariate analysis, the increased risk was associated with multiple sexual partners (P = 0.0124) and greater number of induced abortions (P = 0.0028). The relative risks were 1.3 (95% confidence interval [CI], 1.1 to 1.5) for smokers and 1.5 (95% CI, 1.2 to 2.0) for those who drink alcohol. An inverse relationship was observed in older women and in women with cervical atrophy.

CONCLUSIONS

This study confirmed the relationship between T. vaginalis and multiple sexual partners and suggests that the risk for T. vaginalis also may be related to life-style risk factors.

Trichomonas vaginalis and Tritrichomonas foetus secrete neuraminidase into the culture medium

Supernatants taken from axenic cultures of Trichomonas vaginalis and Tritrichomonas foetus contain a neuraminidase activity, the detection of which is augmented when the trichomonad culture media are supplemented with 30% supernatant of confluent epithelial cultures. The enzyme was active against human erythrocytes, which became highly reactive to peanut agglutinin lectin. The specificity of the enzyme was checked by using a substrate specific to neuraminidase: 2'-(4-methylumbelliferyl)-alpha-D-N-acetylneuramic acid.

Presence of laminin-binding proteins in trichomonads and their role in adhesion

Adhesion is regarded as an important feature in the pathogenesis of various microorganisms. Ability to recognize extracellular matrix proteins, such as laminin or fibronectin, has been correlated with invasiveness. We report that laminin enhances the adhesion of the parasitic protozoa Trichomonas vaginalis and Tritrichomonas foetus to a polystyrene substrate and to the surface of epithelial cells (Madin-Darby canine kidney cell line) in vitro. The enhancement was higher for T. vaginalis than for T. foetus. Addition of anti-laminin antibodies to medium significantly inhibited the adhesion of parasites to polystyrene substrate. Indirect immunofluorescence and transmission electron microscopy of replicas of the parasite's surface labeled with antibody-gold complexes showed laminin-binding sites distributed over the parasite surface. Iodinated P1 fragment of laminin, which retains the laminin-binding site, binds saturably to the parasite surface with a Kd of 19.5 nM, for about 3 X 10(5) binding sites per cell. Immunoblotting analysis of whole parasite extracts showed that a protein of 118 kDa is responsible for laminin binding.

Isolation and differentiation of herpes simplex virus and Trichomonas vaginalis in cell culture

During the period January 1982 to January 1985, 2,234 specimens were cultured for isolation of herpes simplex virus (HSV). HSV was isolated from 23% of these, Trichomonas vaginalis was isolated from 1.6%, and 75.3% were negative. In 0.2% of these, HSV and T. vaginalis were isolated from the same specimen. Cytopathic effects produced by HSV were identified by their sensitivity to arabinosylthymine, whereas those produced by T. vaginalis were identified by their lack of sensitivity to arabinosylthymine and by observation of motility. Cytopathic effects produced by T. vaginalis were reproduced by trophozoites from axenic cultures of T. vaginalis as well as by lysates of T. vaginalis added to serum-free BHK cells.

Pathogenic Trichomonas vaginalis cytotoxicity to cell culture monolayers

Exposure of monolayer cultures of human urogenital and vaginal (HeLa), human epithelial (HEp-2), normal baboon testicular (NBT), and monkey kidney (Vero) cells to live pathogenic Trichomonas vaginalis resulted in extensive disruption of monolayers. Trypan blue was taken up by all host cells released from cell monolayers, which indicated irreversible damage of these cell types by trichomonads. Time and dose related data on cytotoxicity kinetics were obtained using increasing ratios of parasites to cells. All cell types were most sensitive to trichomonads at a multiplicity of infection of one. Release of tritiated thymidine (3H-thymidine) of the deoxyribonucleic acid (DNA) of prelabelled host cells after incubation with T vaginalis corroborated that extensive cytotoxicity was caused by pathogenic trichomonads in man. Only living parasites were cytotoxic, and no trichomonal toxic products were implicated in disruption of the cell monolayer cultures. A pathogenic bovine trichomonad, Tritrichomonas foetus KV-1, produced half as much cell damage as did T vaginalis. Trichomonas tenax, a non-pathogenic member of the normal flora of the oral cavity in man, produced no measurable cytotoxicity to HeLa cells when compared with the pathogenic human trichomonads.

Antibody to Trichomonas vaginalis in human cervicovaginal secretions

Human cervicovaginal secretions were obtained from patients at the Gynecology and Obstetrics Clinics at National Taiwan University Hospital and Cathay General Hospital, Republic of China. Among the 500 patients examined, 33 (6.6%) were infected with Trichomonas vaginalis as determined by the culture method. Secretions from 24 of the infected patients and 30 noninfected women were assayed for anti-T. vaginalis immunoglobulins by the indirect immunofluorescent antibody technique. A few serum samples from both infected and noninfected persons were also included in this study. Immunoglobulin G (IgG) antibody against T. vaginalis was detected in 17 (70.8%) secretions from the infected women. Among the 17 positive secretions, anti-parasite IgA was found in two specimens, IgE was found in three, and IgM was found in one. Of the 30 secretions, 7 (23.3%) from noninfected women also contained anti-parasite IgG. Low levels of natural anti-trichomonad IgG and IgM were detected in the sera of normal persons. Infection with T. vaginalis caused an increase in the serum IgG antibody titer. Cross-reaction between T. vaginalis and Pentatrichomonas hominis was also observed.

Host plasma proteins on the surface of pathogenic Trichomonas vaginalis

Sodium dodecyl sulfate-gel electrophoresis and fluorography and fluorography technology revealed that pathogenic Trichomonas vaginalis was able to acquire numerous loosely associated plasma proteins during incubation in normal human plasma. These proteins were readily removed by repeated washing of the parasite in phosphate-buffered saline. Plasma proteins avidly bound to the surface of T. vaginalis were also detected using a highly sensitive and specific agglutination assay with protein A-bearing Staphylococcus aureus pretreated with monospecific antiserum directed against individual human serum proteins. These avidly associated plasma proteins could not be removed by repeated washing in phosphate-buffered saline or by treatment of washed, live organisms with surface-modifying reagents such as trypsin and periodate. A combined radioimmunoprecipitation-gel electrophoresis-fluorography methodology indicated that parasite biosynthesis of hostlike macromolecules was not responsible for the observed agglutination and reinforced the idea of trichosomal acquisition of plasma components. Finally, incubation of trichomonads with plasma in various buffers at different pH values did not alter the agglutination patterns. These and other data suggest that specific membrane sites trichomonal binding of host proteins. The biological significance of our results is discussed.