Gynaecological infections as risk determinants of subsequent cervical neoplasia

Trichomonas vaginalis: a review of epidemiologic, clinical and treatment issues

Trichomonas vaginalis (TV) is likely the most common non-viral sexually transmitted infection (STI) in the world. It is as an important source of reproductive morbidity, a facilitator of HIV transmission and acquisition, and thus it is an important public health problem. Despite its importance in human reproductive health and HIV transmission, it is not a reportable disease and surveillance is not generally done. This is problematic since most persons infected with TV are asymptomatic. Metronidazole (MTZ) has been the treatment of choice for women for decades, and single dose has been considered the first line of therapy. However, high rates of retest positive are found among TV infected persons after single dose MTZ treatment. This has not been explained by drug resistance since in vitro resistance is only 2-5 %. Treatment failure can range from 7-10 % and even higher among HIV+ women. Treatment efficacy may be influenced by vaginal ecology. The origins of repeat positives need further explanation and better treatment options are needed.

Genetic diversity of Trichomonas vaginalis clinical isolates from Henan province in central China

Trichomonas vaginalis is a flagellated protozoan parasite that infects the human urogenital tract, causing the most common non-viral, sexually transmitted disease worldwide. In this study, genetic variants of T. vaginalis were identified in Henan Province, China. Fragments of the small subunit of nuclear ribosomal RNA (18S rRNA) were amplified from 32 T. vaginalis isolates obtained from seven regions of Henan Province. Overall, 18 haplotypes were determined from the 18S rRNA sequences. Each sampled population and the total population displayed high haplotype diversity (Hd), accompanied by very low nucleotide diversity (Pi). In these molecular genetic variants, 91.58% genetic variation was derived from intra-regions. Phylogenetic analysis revealed no correlation between phylogeny and geographic distribution. Demographic analysis supported population expansion of T. vaginalis isolates from central China. Our findings showing moderate-to-high genetic variations in the 32 isolates of T. vaginalis provide useful knowledge for monitoring changes in parasite populations for the development of future control strategies.

Epidemiology and treatment of trichomoniasis

Trichomonas vaginalis is the most common nonviral sexually transmitted infection (STI) in the world. It was once thought to be a nuisance STI, but it is now being recognized as an important source of reproductive morbidity and a facilitator of HIV transmission and acquisition, and thus it is an important public health problem. The prevalence of T. vaginalis varies greatly by geography and risk group, but is more common among persons of African descent and appears to increase with age, though this may be a screening phenomenon. Wet mount and culture are simple diagnostics, but have lower sensitivity than nucleic acid amplification techniques presently approved for women only. Single dose (2 g) metronidazole (MTZ) for both the index patient and their sexual partners is the preferred treatment. High rates of retest positivity are found after single-dose treatment which are likely due to clinical resistance rather than re-infection and/or drug resistance.

Synthesis and in vitro and in vivo biological evaluation of substituted nitroquinoxalin-2-ones and 2,3-diones as novel trichomonacidal agents

Two series of ten novel 7-nitroquinoxalin-2-ones and ten 6-nitroquinoxaline-2,3-diones with diverse substituents at positions 1 and 4 were synthesized and evaluated against the sexually transmitted parasite Trichomonas vaginalis. Furthermore, diverse molecular and drug-likeness properties were analyzed to predict the oral bioavailability following the Lipinski's "rule of five". 7-Nitroquinoxalin-2-one derivatives displayed moderate to high in vitro activity while the efficiency of most nitroquinoxaline-2,3-diones was rather low; both kinds of compounds did not show cytotoxic effects in mammalian cells. 7-Nitro-4-(3-piperidinopropyl)quinoxalin-2-one 9 achieved the highest trichomonacidal activity (IC50 = 18.26 μM) and was subsequently assayed in vivo in a murine model of trichomonosis. A 46.13% and a 50.70% reduction of pathogenic injuries were observed in the experimental groups treated orally during 7 days with 50 mg/kg and 100 mg/kg doses. The results obtained in the biological assays against T. vaginalis indicate that compounds with ω-(dialkylamino)alkyl substituents and a keto group at positions 4 and 2 of quinoxaline ring, respectively, provide interesting structural cores to develop novel prototypes to enhance the nitroquinoxalinones activity as trichomonacidal agents with interesting ADME properties according to virtual screening analysis.

MBL2 polymorphisms in women with atypical squamous cells of undetermined significance

Infection with high risk Human papillomavirus (HPV) is the main known cause of cervical cancer. HPV induces different grades of lesions: among them, Atypical squamous cells of undetermined significance are abnormal lesions that could evolve in pre-cancer lesions or spontaneously regress. The mannose binding lectin (MBL) is an innate immunity serum protein also found in cervico-vaginal mucosa, whose expression is known to be affected by polymorphisms in exon 1 and promoter of the MBL2 gene. In the present study the possible association between MBL2 functional polymorphisms and susceptibility to develop atypical squamous cells of undetermined significance was investigated in a group of women from North-East of Italy, stratified for HPV infection status. The MBL2 D and O alleles and the deficient producer combined genotypes, responsible for low MBL production, were more represented among atypical squamous cells of undetermined significance positive women than healthy controls and the results were confirmed when only HPV negative samples were considered. These results suggest a possible involvement of MBL2 functional polymorphisms in atypical squamous cells of undetermined significance susceptibility.

Prevalence and risk factors for cervical neoplasia: a cervical cancer screening program in Beijing

Background

Cervical cancer is the second most common cancer and cause of cancer-related death for women worldwide. The aims of this study were to investigate the prevalence of cervical neoplasia and examine factors associated with high-grade cervical squamous intraepithelial lesions (HSIL) among women taking part in a cervical cancer screening program in Beijing.

Methods

Women aged 25–65 years were screened using the ThinPrep cytologic test and gynecologic examination. Univariate and multivariate logistic regressions were conducted to investigate factors associated with HSIL.

Results

Among 728,704 women screened, the prevalence of cervical intraepithelial neoplasia (CIN) I, II, III was 50.2, 34.0, and 36.4 per 100,000, respectively. Prevalence of cervical cancer was 12.2 per 100,000. Risk factors for HSIL included being in age group of 46–55 years (adjusted odds ratio [aOR] = 1.15, 95% CI: 1.07–1.44, compared with the 25–35 age group), bleeding after intercourse (aOR = 2.08, 95% CI: 1.40–3.10), and presence of trichomonas vaginalis infection (aOR = 2.62, 95% CI: 1.35–5.07), cervical inflammation (aOR = 4.22, 95% CI: 3.39–5.26), and genital warts (aOR = 3.89, 95% CI: 2.54–7.70). High education level (college and above compared with junior middle school or lower) was found to be protective (aOR = 0.79, 95% CI: 0.37–0.90).

Conclusions

The prevalence of cervical neoplasia is relatively high in Beijing. Women aged 46–55 years, those with a lower education level, those reporting bleeding after intercourse, and those affected by Trichomonas vaginalis infection, cervical inflammation and genital warts are at higher risk for HSIL. Particular efforts should be made to ensure these women are included in cervical cancer screening programs.

An association between Trichomonas vaginalis and high-risk human papillomavirus in rural Tanzanian women undergoing cervical cancer screening

OBJECTIVE

The goal of this study was to determine the prevalence of vaginitis and its association with high-risk human papillomavirus (HR HPV) in women undergoing cervical cancer screening in rural Tanzania.

METHODS

For the purpose of cervical cancer screening, cytology and HR HPV polymerase chain reaction data were collected from 324 women aged between 30 and 60 years. Microscopy and gram stains were used to detect yeast and bacterial vaginosis. Cervical nucleic acid amplification test specimens were collected for the detection of Trichomonas vaginalis (TV), Chlamydia trachomatis, and Neisseria gonorrhoeae.

RESULTS

The majority of women were married (320 of 324) and reported having a single sexual partner (270 of 324); the median age of participants was 41 years. HR HPV was detected in 42 participants. Forty-seven percent of women had vaginitis. Bacterial vaginosis was the most common infection (32.4%), followed by TV (10.4%), and yeast (6.8%). In multivariable logistic regression analysis, TV was associated with an increased risk of HR HPV (odds ratio, 4.2 [95% CI, 1.7-10.3]). Patients with TV were 6.5 times more likely to have HPV type 16 than patients negative for TV (50% vs 13.3%) (odds ratio, 6.5 [95% CI, 1.1-37]).

CONCLUSIONS

Among rural Tanzanian women who presented for cervical cancer screening, Trichomonas vaginitis was significantly associated with HR HPV infection (specifically type 16).

Putrescine-dependent re-localization of TvCP39, a cysteine proteinase involved in Trichomonas vaginalis cytotoxicity

Polyamines are involved in the regulation of some Trichomonas vaginalis virulence factors such as the transcript, proteolytic activity, and cytotoxicity of TvCP65, a cysteine proteinase (CP) involved in the trichomonal cytotoxicity. In this work, we reported the putrescine effect on TvCP39, other CP that also participate in the trichomonal cytotoxicity. Parasites treated with 1,4-diamino-2-butanone (DAB) (an inhibitor of putrescine biosynthesis), diminished the amount and proteolytic activity of TvCP39 as compared with untreated parasites. Inhibition of putrescine biosynthesis also reduced ∼80% the tvcp39 mRNA levels according to RT-PCR and qRT-PCR assays. Additionally, actinomycin D-treatment showed that the tvcp39 mRNA half-life decreased in the absence of putrescine. However, this reduction was restored by exogenous putrescine addition, suggesting that putrescine is necessary for tvcp39 mRNA stability. TvCP39 was localized in the cytoplasm but, in DAB treated parasites transferred into exogenous putrescine culture media, TvCP39 was re-localized to the nucleus and nuclear periphery of trichomonads. Interestingly, the amount and proteolytic activity of TvCP39 was recovered as well as the tvcp39 mRNA levels were restored when putrescine exogenous was added to the DAB-treated parasites. In conclusion, our data show that putrescine regulate the TvCP39 expression, protein amount, proteolytic activity, and cellular localization.

Anti-Trichomonas vaginalis activity from triterpenoid derivatives

Trichomonas vaginalis is a flagellated parasite that causes trichomonosis, the most common non-viral sexually transmitted disease (STD) in the world. Worryingly, trichomonosis is associated to increased transmission of HIV. Due to high frequency of the infection during pregnancy and the development of metronidazole-resistant isolates, therapeutic alternatives to 5-nitroimidazole are being searched. Triterpenes are natural products presenting several biological activities such as anti-protozoal activity. The aim of this study was to evaluate the in vitro anti-T. vaginalis activity from betulinic and ursolic acids, as well as semisynthetic derivatives obtained. Compounds obtained from betulinic acid presented better activity than those from ursolic acid. Piperazine derivatived from betulinic acid presented minimum inhibitory concentration (MIC) value of 91.2 μM, and the kinetic growth curve performed with parasites treated with this most active compound revealed complete inhibition of trophozoite proliferation at 2 h of incubation and total abolition of trophozoite growth in 24 h, revealing that the piperazine derivative is an efficient trichomonacidal molecule. The same compound promoted total erythrocyte lysis and lactate dehydrogenase (LDH) liberation of 83 and 100% (at 45.6 and 91.2 μM, respectively), indicating parasite membrane damage. The piperazine derivative demonstrated cytotoxic effect against the HMVII and HeLa cell lineages at the MIC value. This is the first report of semisynthetic triterpenoid derivatives with anti-T. vaginalis activity, revealing the high potential of these compounds as trichomonacidal agents.

Runs of homozygosity and a cluster of vulvar cancer in young Australian Aboriginal women

OBJECTIVE

A cluster of vulvar cancer exists in young Aboriginal women living in remote communities in Arnhem Land, Australia. A genetic case-control study was undertaken involving 30 cases of invasive vulvar cancer and its precursor lesion, high-grade vulvar intraepithelial neoplasia (VIN), and 61 controls, matched for age and community of residence. It was hypothesized that this small, isolated population may exhibit increased autozygosity, implicating recessive effects as a possible mechanism for increased susceptibility to vulvar cancer.

METHODS

Genotyping data from saliva samples were used to identify runs of homozygosity (ROH) in order to calculate estimates of genome-wide homozygosity.

RESULTS

No evidence of an effect of genome-wide homozygosity on vulvar cancer and VIN in East Arnhem women was found, nor was any individual ROH found to be significantly associated with case status. This study found further evidence supporting an association between previous diagnosis of CIN and diagnosis of vulvar cancer or VIN, but found no association with any other medical history variable.

CONCLUSIONS

These findings do not eliminate the possibility of genetic risk factors being involved in this cancer cluster, but rather suggest that alternative analytical strategies and genetic models should be explored.

Association of Trichomonas vaginalis and cytological abnormalities of the cervix in low risk women

Objective

Is Trichomonas vaginalis (TV) an inducing factor for the development of (pre-)cancerous lesions of the cervix?

Design

Cross sectional study.

Setting

Screening healthy Belgian women with low infection risk.

Sample

63,251 consecutive liquid based cervical samples.

Methods

Real time quantitative PCR for presence of TV, 18 HPV types and Pap smear analysis of cytologic abnormalities.

Main Outcome Measures

Association of TV and HPV with cervix dysplasia

Results

The overall prevalence of TV DNA was 0.37%, of low risk HPV 2%, of high risk HPV 13.2%, and 8.8 % had cytological abnormalities. Both LR-HPV and HR-HPV were significantly associated with all cytological abnormalities. Presence of TV was associated with LR- and HR-HPV, ASC-US and HSIL, but not with other abnormalities. All women with TV and HSIL also had HR-HPV, while the latter was present in only 59% of women with TV and ASC-US. Amongst HPV negative women, TV was found in 1.3% of women with ASC-US, but only in 0.03% of women with normal cytology (OR 4.2, CL95% 2.1-8.6). In HR-HPV positive women, presence of TV increased the likelihood of cytological abnormalities somewhat (P=0.05), mainly due to an increase in ASC-US and LSIL, but not HSIL.

Conclusions

We conclude that TV infection is associated with both LR and HR-HPV infection of the cervix, as well as with ASC-US and HSIL. TV is a concomitant STI, but is not thought to be a co-factor in the causation of HSIL and cervical cancer. However, TV may cause false positive diagnoses of ASC-US.

In vitro anti-Trichomonas vaginalis activity of Pistacia lentiscus mastic and Ocimum basilicum essential oil

Trichomonas vaginalis is a protozoan parasite that causes trichomoniasis; a cosmopolitan sexually transmitted disease. Metronidazole is the drug of choice for T. vaginalis infections. The increase in metronidazole resistant parasites and undesirable side effects of this drug makes the search for an alternative a priority for the management of trichomoniasis. Pistacia lentiscus mastic and Ocimum basilicum oil are known for their antibacterial, antifungal, antiviral and antiprotozoal effects. The present study was carried out to investigate the in vitro effects of P. lentiscus mastic and O. basilicum oil on T. vaginalis trophozoites. The effects of different concentrations of P. lentiscus mastic (15, 10 and 5 mg/ml) and different concentrations of O. basilicum oil (30, 20 and 10 μg/ml) on multiplication of trophozoites at different time points (after 24, 48, 72 and 96 h) were determined, also morphological changes were reported by transmission electron microscopy (TEM). The results showed that both plants caused an inhibition of growth of T. vaginalis trophozoites. The minimal lethal concentration of P. lentiscus mastic was 15 mg/ml after 24 h incubation, 10 mg/ml after 48 h and 5 mg/ml after 96 h. The minimal lethal concentration of O. basilicum oil was 30 μg/ml after 24 h incubation, 20 μg/ml after 48 h and 10 μg/ml after 96 h. TEM study of trophozoites treated by P. lentiscus mastic or by O. basilicum oil showed considerable damage of the membrane system of the trophozoites, and extensive vacuolization of the cytoplasm. These results highly suggest that P. lentiscus mastic and O. basilicum oil may be promising phytotherapeutic agents for trichomoniasis treatment.

TvMP50 is an immunogenic metalloproteinase during male trichomoniasis

Trichomonas vaginalis, a human urogenital tract parasite, is capable of surviving in the male microenvironment, despite of the presence of Zn(2+). Concentrations > 1.6 mM of Zn(2+) have a trichomonacidal effect; however, in the presence of ≤1.6 mM Zn(2+), several trichomonad proteins are up- or down-regulated. Herein, we analyzed the proteome of a T. vaginalis male isolate (HGMN01) grown in the presence of Zn(2+) and found 32 protein spots that were immunorecognized by male trichomoniasis patient serum. Using mass spectrometry (MS), the proteins were identified and compared with 23 spots that were immunorecognized in the proteome of a female isolate using the same serum. Interestingly, we found a 50-kDa metallopeptidase (TvMP50). Unexpectedly, this proteinase was immunodetected by the serum of male trichomoniasis patients but not by the female patient serum or sera from healthy men and women. We analyzed the T. vaginalis genome and localized the mp50 gene in locus TVAG_403460. Using an RT-PCR assay, we amplified a 1320-bp mp50 mRNA transcript that was expressed in the presence of Zn(2+) in the HGMN01 and CNCD147 T. vaginalis isolates. According to a Western blot assay, native TvMP50 was differentially expressed in the presence of Zn(2+). The TvMP50 proteolytic activity increased in the presence of Zn(2+) in both isolates and was inhibited by EDTA but not by ptosyl-L-lysine chloromethyl ketone (TLCK), E64, leupeptin, or phenylmethane sulfonyl fluoride. Furthermore, the recombinant TvMP50 had proteolytic activity that was inhibited by EDTA. These data suggested that TvMP50 is immunogenic during male trichomoniasis, and Zn(2+) induces its expression.

Remarkable anti-trichomonas vaginalis activity of plants traditionally used by the Mbyá-Guarani indigenous group in Brazil

Trichomonas vaginalis, a flagellate protozoan, is the causative agent of trichomonosis, the most common nonviral sexually transmitted disease worldwide. Taking into account the increased prevalence of metronidazole-resistant isolates, alternative drugs are essential for the successful treatment. Natural products are the source of most new drugs, and popular wisdom about the use of medicinal plants is a powerful tool in this search. In this study, the activity of 10 medicinal plants extensively used in daily life by Mbyá-Guarani indigenous group was evaluated against seven different T. vaginalis isolates. Among the aqueous extracts tested, Verbena sp. (Guachu ka'a in Mbyá-Guarani language) and Campomanesia xanthocarpa (Guavira in Mbyá-Guarani language) showed the highest activity against T. vaginalis with MIC value of 4.0 mg/mL reaching 100% of efficacy against the parasite. The kinetic growth assays showed that the extracts promoted complete growth abolishment after 4 h of incubation. In addition, the extracts tested did not promote a significant hemolytic activity against human erythrocytes. Our results show for the first time the potential activity of Verbena sp. and C. xanthocarpa against T. vaginalis. In addition, this study demonstrates that indigenous knowledge is an important source of new prototype antiprotozoal agents.

Trichomonas vaginalis and Tritrichomonas foetus: interaction with fibroblasts and muscle cells - new insights into parasite-mediated host cell cytotoxicity

Trichomonas vaginalis and Tritrichomonas foetus are parasitic, flagellated protists that inhabit the urogenital tract of humans and bovines, respectively. T. vaginalis causes the most prevalent non-viral sexually transmitted disease worldwide and has been associated with an increased risk for human immunodeficiency virus-1 infection in humans. Infections by T. foetus cause significant losses to the beef industry worldwide due to infertility and spontaneous abortion in cows. Several studies have shown a close association between trichomonads and the epithelium of the urogenital tract. However, little is known concerning the interaction of trichomonads with cells from deeper tissues, such as fibroblasts and muscle cells. Published parasite-host cell interaction studies have reported contradictory results regarding the ability of T. foetus and T. vaginalis to interact with and damage cells of different tissues. In this study, parasite-host cell interactions were examined by culturing primary human fibroblasts obtained from abdominal biopsies performed during plastic surgeries with trichomonads. In addition, mouse 3T3 fibroblasts, primary chick embryo myogenic cells and L6 muscle cells were also used as models of target cells. The parasite-host cell cultures were processed for scanning and transmission electron microscopy and were tested for cell viability and cell death. JC-1 staining, which measures mitochondrial membrane potential, was used to determine whether the parasites induced target cell damage. Terminal deoxynucleotidyltransferase-mediated dUTP nick end labelling staining was used as an indicator of chromatin damage. The colorimetric crystal violet assay was performed to ana-lyse the cytotoxicity induced by the parasite. The results showed that T. foetus and T. vaginalis adhered to and were cytotoxic to both fibroblasts and muscle cells, indicating that trichomonas infection of the connective and muscle tissues is likely to occur; such infections could cause serious risks to the infected host.

Analysis of the NTPDase and ecto-5'-nucleotidase profiles in serum-limited Trichomonas vaginalis

Trichomonas vaginalis is a parasite of the human urogenital tract that causes trichomonosis, the most prevalent non-viral sexually transmitted disease. Ectonucleoside triphosphate diphosphohydrolase (NTPDase) family members, which hydrolyse extracellular ATP and ADP and ecto-5'-nucleotidase, which hydrolyses AMP, have been characterised in T. vaginalis. For trichomonad culture, the growth medium is supplemented with 10% serum, which is an important source of nutrients, such as adenosine. Here, we investigated the ATP metabolism of T. vaginalis trophozoites from long-term cultures and clinical isolates under limited bovine serum conditions (1% serum). The specific enzymatic activities were expressed as nmol inorganic phosphate (Pi) released/min/mg protein, the gene expression patterns were determined by reverse transcriptase-polymerase chain reaction, the extracellular adenine nucleotide hydrolysis was analysed by high performance liquid chromatography and the cell cycle analysis was assessed by flow cytometry. Serum limitation led to the profound activation of NTPDase and ecto-5'-nucleotidase activities. Furthermore, the levels of NTPDase A and B transcripts increased and extracellular ATP metabolism was activated, which led to enhanced ATP hydrolysis and the formation of ADP and AMP. Moreover, the cell cycle was arrested at the G0/G1 stage, which suggested adenosine uptake. Our data suggest that under conditions of serum limitation, NTPDase and ecto-5'-nucleotidase play a role in providing the adenosine required for T. vaginalis growth and that this process contributes to the establishment of parasitism.

Prevalence of human papillomavirus and co-existent sexually transmitted infections among female sex workers, men having sex with men and injectable drug abusers from eastern India

BACKGROUND

Human papillomavirus (HPV) is a very common sexually transmitted disease affecting both men and women and is responsible for different ano-genital cancers in either sex. Co-existing sexually transmitted infections (STI) including HIV have been considered as important co-factors for carcinogenesis induced by HPV. The purpose of this study was to determine the prevalence of any HPV, HPV 16 and HPV 18 and also concomitant STIs among female sex workers (FSW), men having sex with men (MSM) and injectable drug users (IDU).

MATERIAL AND METHOD

This cross-sectional study was conducted among 45 FSWs, 26 MSMs and 58 IDUs who attended the STI or de-addiction clinics. Genital scrape samples collected from glans penis and coronal sulcus in males and cervical squamo-columnar junction in females were tested for HPV DNA by PCR using HPV L1 consensus primer. Type specific PCR to detect HPV 16 and 18 was done on the samples positive on consensus PCR. All participants were tested for associated STIs including HIV and hepatitis B and cervical cytology was done on all females.

RESULTS

Among the FSWs, HPV was detected in 73.3% and HPV 16 and 18 was detected in 25.7%. Though the HPV prevalence was similarly high among MSMs (69.2%) and IDUs (72.4%), the prevalence of HPV 16 and 18 was much lower in these groups compared to the FSWs. Prevalence of cervico-vaginal infection with Trichomonas vaginalis and syphilis was significantly higher in the HPV positive women compared to the HPV negative women. There was no statistically significant difference in the prevalence of other STIs among HPV positive and negative women and men.

CONCLUSION

HPV infection is highly prevalent among FSW, MSM and IDUs. Trichomonas vaginalis infection is more frequent in HPV positive women.

Endobiont viruses sensed by the human host - beyond conventional antiparasitic therapy

Wide-spread protozoan parasites carry endosymbiotic dsRNA viruses with uncharted implications to the human host. Among them, Trichomonas vaginalis, a parasite adapted to the human genitourinary tract, infects globally ∼250 million each year rendering them more susceptible to devastating pregnancy complications (especially preterm birth), HIV infection and HPV-related cancer. While first-line antibiotic treatment (metronidazole) commonly kills the protozoan pathogen, it fails to improve reproductive outcome. We show that endosymbiotic Trichomonasvirus, highly prevalent in T. vaginalis clinical isolates, is sensed by the human epithelial cells via Toll-like receptor 3, triggering Interferon Regulating Factor -3, interferon type I and proinflammatory cascades previously implicated in preterm birth and HIV-1 susceptibility. Metronidazole treatment amplified these proinflammatory responses. Thus, a new paradigm targeting the protozoan viruses along with the protozoan host may prevent trichomoniasis-attributable inflammatory sequelae.

Transcriptomic identification of iron-regulated and iron-independent gene copies within the heavily duplicated Trichomonas vaginalis genome

Gene duplication is an important evolutionary mechanism and no eukaryote has more duplicated gene families than the parasitic protist Trichomonas vaginalis. Iron is an essential nutrient for Trichomonas and plays a pivotal role in the establishment of infection, proliferation, and virulence. To gain insight into the role of iron in T. vaginalis gene expression and genome evolution, we screened iron-regulated genes using an oligonucleotide microarray for T. vaginalis and by comparative EST (expressed sequence tag) sequencing of cDNA libraries derived from trichomonads cultivated under iron-rich (+Fe) and iron-restricted (−Fe) conditions. Among 19,000 ESTs from both libraries, we identified 336 iron-regulated genes, of which 165 were upregulated under +Fe conditions and 171 under −Fe conditions. The microarray analysis revealed that 195 of 4,950 unique genes were differentially expressed. Of these, 117 genes were upregulated under +Fe conditions and 78 were upregulated under −Fe conditions. The results of both methods were congruent concerning the regulatory trends and the representation of gene categories. Under +Fe conditions, the expression of proteins involved in carbohydrate metabolism, particularly in the energy metabolism of hydrogenosomes, and in methionine catabolism was increased. The iron–sulfur cluster assembly machinery and certain cysteine proteases are of particular importance among the proteins upregulated under −Fe conditions. A unique feature of the T. vaginalis genome is the retention during evolution of multiple paralogous copies for a majority of all genes. Although the origins and reasons for this gene expansion remain unclear, the retention of multiple gene copies could provide an opportunity to evolve differential expression during growth in variable environmental conditions. For genes whose expression was affected by iron, we found that iron influenced the expression of only some of the paralogous copies, whereas the expression of the other paralogs was iron independent. This finding indicates a very stringent regulation of the differentially expressed paralogous genes in response to changes in the availability of exogenous nutrients and provides insight into the evolutionary rationale underlying massive paralog retention in the Trichomonas genome.

Performance of rapid immunochromatographic assay in the diagnosis of Trichomoniasis vaginalis

Trichomonas vaginalis accounts for nearly half of all curable sexually transmitted diseases worldwide with serious health consequences. Effort to increase the sensitivity of its diagnosis is critical to both control measures and epidemiologic studies. This study was conducted to evaluate the OSOM® Trichomonas Rapid Test (Sekisui Diagnostics, Framingham, MA, USA), a qualitative antigen-detection immunochromatographic (IC) assay in the diagnosis of vaginal trichomoniasis comparable to the conventional methods. The study enrolled 258 females aged 18-50 years classified into symptomatic (185) and asymptomatic (73) groups. Vaginal swab specimens were obtained for wet mount, stained preparation (Giemsa, acridine-orange), culture (InPouch TV™, modified Diamond's), and for rapid OSOM testing. Trichomonas vaginalis was detected in 67, 66, 71, 99, 96, and 97 using wet mount, acridine-orange stain, Giemsa stain, modified Diamond's, InPouch media, and OSOM test, respectively. In comparison to a composite reference standard (CRS) of wet mount microscopy and culture, OSOM test reported 97.98%, 99.37%, 98.98%, 98.75%, and 98.84% for sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy, respectively. The OSOM test proved to be a simple and objective test. This rapid point-of-care-test will contribute significantly in the diagnosis of vaginal trichomoniasis and will increase the understanding of its still vague epidemiology.

Mycoplasma hominis in Cuban Trichomonas vaginalis isolates: association with parasite genetic polymorphism

Trichomonas vaginalis can be naturally infected with intracellular Mycoplasma hominis. This bacterial infection may have implications for trichomonal virulence and disease pathogenesis. The objective of the study was to report the presence of M. hominis in Cuban T. vaginalis isolates and to describe the association between the phenotype M. hominis infected with RAPD genetic polymorphism of T. vaginalis. The Random Amplified Polymorphic DNA (RAPD) technique was used to determine genetic differences among 40 isolates of T. vaginalis using a panel of 30 random primers and these genetic data were correlated with the infection of isolates with M. hominis. The trees drawn based on RAPD data showed no relations with metronidazole susceptibility and significantly association with the presence of M. hominis (P=0.043), which demonstrates the existence of concordance between the genetic relatedness and the presence of M. hominis in T. vaginalis isolates. This result could point to a predisposition of T. vaginalis for the bacterial enters and/or survival.

Lycorine derivatives against Trichomonas vaginalis

Six lycorine derivatives were prepared, characterized, and evaluated for their in vitro anti-Trichomonas vaginalis activity. Compounds bearing an acetyl (2), lauroyl (3), benzoyl (4 and 5), and p-nitrobenzoyl (6 and 7) groups were synthesized. The best activity was achieved with lycorine esterified at C-2 position with lauroyl group. Preliminary structure-activity relationship points that unprotected OH group at C-1 and C-2 is not necessary to the antiparasitic activity, and none of the derivative was less active than lycorine. The lycorine structural requisites required to kill this amitochondriate cell seem to be different in comparison with the derivatives most active against other parasites and tumor cell lines, both mitochondriated cells. This result is an important contribution with our ongoing studies regarding the mechanism of action of the Amaryllidaceae alkaloids on T. vaginalis cell death opening a new perspective to optimize this innovative pharmacological potential.

Involvement of purinergic signaling on nitric oxide production by neutrophils stimulated with Trichomonas vaginalis

Trichomonas vaginalis is a parasite from the human urogenital tract that causes trichomonosis, the most prevalent non-viral sexually transmitted disease. The neutrophil infiltration has been considered to be primarily responsible for cytological changes observed at infection site, and the chemoattractants can play an important role in this leukocytic recruitment. Nitric oxide (NO) is one of the most widespread mediator compounds, and it is implicated in modulation of immunological mechanisms. Extracellular nucleotides and nucleosides are signaling molecules involved in several processes, including immune responses and control of leukocyte trafficking. Ectonucleoside triphosphate diphosphohydrolase members, ecto-5'-nucleotidase, and adenosine deaminase (ectoADA) have been characterized in T. vaginalis. Herein, we investigated the effects of purinergic system on NO production by neutrophils stimulated with T. vaginalis. The trophozoites were able to induce a high NO synthesis by neutrophils through iNOS pathway. The extracellular nucleotides ATP, ADP, and ATPγS (a non-hydrolyzable ATP analog) showed no significant change in NO secretion. In contrast, adenosine and its degradation product, inosine, promoted a low production of the compound. The immunosuppressive effect of adenosine upon NO release by neutrophils occurred due to adenosine A(2A) receptor activation. The ecto-5'-nucleotidase activity displayed by T. vaginalis was shown to be important in adenosine generation, indicating the efficiency of purinergic cascade. Our data suggest the influence of purinergic signaling, specifically adenosinergic system, on NO production by neutrophils in T. vaginalis infection, contributing to the immunological aspects of disease.

Genetic characterization of three Cuban Trichomonas vaginalis virus. Phylogeny of Totiviridae family

Trichomonas vaginalis can be infected with double stranded RNA (dsRNA) viruses known as T. vaginalis virus (TVV). This viral infection may have important implications for trichomonal virulence and disease pathogenesis. In this study we identified and genetic characterized three strains of TVVs isolated from T. vaginalis in Cuba. The three new predicted sequences of capsid protein and RNA-dependent RNA polymerase amounted to the previously determined 20 TVV sequences and other 21 viruses of Totiviridae family were used for a phylogenetic analysis. Four distinct monophyletic clades are shown in a phylogenetic tree. One corresponds with TVVs, other with Victorivirus, Leishmaniavirus and Eimeria brunetti virus and, other with viruses of the genus Totivirus and the last with Giardiavirus. The E. brunetti virus is identified in the phylogenetic tree as independent taxon between Leishmaniavirus and Victorivirus isolates, most closely related to Victorivirus. TVV constitute a monophyletic cluster distinguishable from all other viruses in Totiviridae family. This result suggested that TVV may be grouped in a separated genus and not inside of Giardiavirus. TVVs appear to be more closely related to protozoan viruses in the genus Leishmaniavirus and to fungal viruses in the genus Victorivirus than to other protozoan and fungal viruses in Giardiavirus and Totivirus. Among TVVs, four main groups can be recognized within Trichomonasvirus cluster, which correspond with the previous species classification proposed. Further studies, with more TVV strains, especially TVV3 and 4 strains, are needed in order to determine the phylogenetic relationship among Trichomonasvirus genus and specifically if TVV2 and 3 each also constitute a well-delimited group.

Antibiotic use and risk of gynecological cancer

OBJECTIVES

Several studies addressed the association between antibiotic use and breast cancer risk. The objective of this study was to assess the association between antibiotic use and risk of cervical, ovarian, and uterine cancer.

STUDY DESIGN

We carried out a population-based case-control study using data from Saskatchewan Health administrative databases (Canada) between the years 1981 and 2000. Cases were matched to 4 controls, using incidence density sampling. The effect of dosage and timing of antibiotic use, over a minimum of 15 years before diagnosis, on cervical, ovarian, or uterine cancer risk was assessed. Number of prescriptions and number of pills were used as exposure definitions. The effect of different classes of antibiotics on cancer risk was also studied.

RESULTS

A total of 1225 cancer cases [192 cervical, 445 ovarian, and 588 uterine] and 4900 matched controls were included in this study. Antibiotic exposure (number of prescriptions) during the period of 1-15 years in the past was significantly associated with a reduced risk of cervical cancer; Relative Risk (RR)=0.40, 0.31, 0.26, and 0.29 for the four exposure quartiles, respectively. No association was found for ovarian or uterine cancer. When number of pills was considered, similar results were found. There was no effect of the timing or class of antibiotic exposure on cervical cancer risk.

CONCLUSIONS

Antibiotic exposure up to 15 years in the past was associated with a decreased risk of cervical cancer. The lack of temporal trends and the absence of class specific effects suggest a non-causal relationship.

Lycorine induces cell death in the amitochondriate parasite, Trichomonas vaginalis, via an alternative non-apoptotic death pathway

In this study, the mechanism of action of the pro-apoptotic alkaloid lycorine on an amitochondriate cell, the parasite Trichomonas vaginalis, was investigated. The cytotoxicity of lycorine against T. vaginalis was studied from 2.5 to 1000μM and several important ultrastructural alterations were observed by electron microscopy. Lycorine arrested the T. vaginalis cell cycle, although no hallmarks of apoptosis, such as apoptotic bodies, were observed. Consequently, the underlying mechanism of action fails to completely fulfill the criteria for apoptosis. However, some similarities to paraptotic cell death were observed.

Kinetic characterization and gene expression of adenosine deaminase in intact trophozoites of Trichomonas vaginalis

Trichomonas vaginalis is a parasite that resides in the human urogenital tract and causes trichomonosis, the most prevalent nonviral sexually transmitted disease. Nucleoside triphosphate diphosphohydrolase (NTPDase), which hydrolyzes extracellular di- and triphosphate nucleotides, and ecto-5'-nucleotidase, which hydrolyzes AMP, have been characterized in T. vaginalis. The aim of this study was to characterize the adenosine deaminase (ADA) activity in intact trophozoites of T. vaginalis. A strong inhibition in adenosine deamination was observed in the presence of calcium and magnesium, which was prevented by EDTA. The apparent K(M) value for adenosine was 1.13 ± 0.07mM. The calculated V(max) was 2.61 ± 0.054 nmol NH(3) min(-1) mg(-1) protein. Adenosine deamination was inhibited in the presence of erythro-9-(2-hydroxy-3-nonyl)adenine. Semi-quantitative reverse transcriptase-PCR experiments were performed and both ADA-related genes ada(125) and ada(231) mRNA were expressed, although ada(231) in higher quantity when compared with the ada(125) : α-tubulin ratio. Furthermore, a phylogenetic analysis showed that the T. vaginalis sequences formed a clade with Entamoeba histolytica and Dictyostelium discoideum sequences, and it strongly suggests homologous functions in the T. vaginalis genome. The presence of ADA activity in T. vaginalis may be important to modulate the adenosine/inosine levels during infection and, consequently, to maintain the anti-inflammatory properties through different nucleoside-signalling mechanisms.

Identification and characterization of a surface-associated, subtilisin-like serine protease inTrichomonas vaginalis

Trichomonas vaginalisis a protozoan parasite causing trichomonosis, a sexually transmitted infection in humans. This parasite has numerous proteases, most of which are cysteine proteases that appear to be involved in adherence and cytotoxicity of host cells. In this report we identify and characterize a putative subtilisin-like serine protease (SUB1). Thesub1gene encodes a 101-kDa protein.In silicoanalyses predict signal and pro-peptides at the N-terminus, and a transmembrane helix at the carboxy-terminal region. Thesub1gene was found as single copy by Southern analysis, albeit additional serine protease related genes are annotated in theT. vaginalisgenome. The expression ofsub1could only be detected by RT-PCR and Ribonuclease Protection Assays, suggesting a low abundant mRNA. Thesub1gene transcription start site was correctly assigned by RPA. The transcript abundance was found to be modulated by the availability of iron in the growth medium. Antibodies raised to a specific SUB1 peptide recognized a single protein band (~82 kDa) in Western blots, possibly representing the mature form of the protein. Immunofluorescence showed SUB1 on the trichomonad surface, and in dispersed vesicles throughout the cytoplasm. A bioinformatic analysis of genes annotated as serine proteases in theT. vaginalisgenome is also presented. To our knowledge this is the first putative serine protease experimentally described forT. vaginalis.

Methyl jasmonate induces cell death and loss of hydrogenosomal membrane potential in Trichomonas vaginalis

Trichomonas vaginalis is an important human parasite of the urogenital tract. Jasmonates are a group of small lipids that are produced in plants and function as stress hormones. Naturally occurring methyl jasmonate (MJ) has been used to treat several types of cancer cells and it is cytotoxic to protistan parasites. It has been suggested that mitochondria are the target organelles of jasmonates. Here, we tested this drug against T. vaginalis. Although metronidazole has been the drug of choice for trichomoniasis, side effects from this treatment are common, and nausea and dizziness have been reported in up to 12% of patients. In addition, there has been increased recognition of resistance to metronidazole. We demonstrate here using flow cytometry, JC-1 and scanning and transmission electron microscopy that MJ induced the cell death of T. vaginalis parasites. Our results are discussed with previous findings published by others.

Immunoproteomics of the active degradome to identify biomarkers for Trichomonas vaginalis

Trichomonas vaginalis, a sexually transmitted parasite, has many cysteine proteinases (CPs); some are involved in trichomonal pathogenesis, express during infection, and antibodies against CPs have been detected in patient sera. The goal of this study was to identify the antigenic proteinases of T. vaginalis as potential biomarkers for trichomonosis. The proteases detected when T. vaginalis protein extracts are incubated without protease inhibitors, the trichomonad-active degradome, and the immunoproteome were obtained by using 2-DE, 2-D-zymograms, 2-D-Western blot (WB) assays with trichomonosis patient sera, and MS analysis. Forty-nine silver-stained spots were detected in the region of 200-21 kDa of parasite protease-resistant extracts. A similar proteolytic pattern was observed in the 2-D zymograms. Nine CPs were identified in the 30 kDa region (TvCP1, TvCP2, TvCP3, TvCP4, TvCP4-like, TvCP12, TvCPT, TvLEGU-1, and another legumain-like CP). The major reactive spots to T. vaginalis-positive patient sera by 2-D-WB corresponded to four papain-like (TvCP2, TvCP4, TvCP4-like, TvCPT), and one legumain-like (TvLEGU-1) CPs. The genes of TvCP4, TvCPT, and TvLEGU-1 were cloned, sequenced, and expressed in Escherichia coli. Purified recombinant CPs were recognized by culture-positive patient sera in 1-D-WB assays. These data show that some CPs could be potential biomarkers for serodiagnosis of trichomonosis.

Immunohistochemical study of the vaginal inflammatory response in experimental trichomoniasis

In the present paper, the acute and subchronical inflammatory processes of the vaginal epithelial were studied in mice experimentally infected with two Trichomonas vaginalis strains of different pathogenicity, by means of histological and immunological methods. There was an increase in the stratified epithelium layers as well as edema produced by the increase of vascularization in the propia submucosa and infiltration of leukocytes. The proliferation of the vaginal epithelium favors the settlement and persistence of the parasitic infection. All of the findings corresponded with signs of a systemic disease being observed in the animals, including significant weight loss and also intestinal invasion. The entire inflammatory process has been corroborated by studies of adhesion molecules such as E-Selectin, VCAM-1 and PECAM-1. A correlation between the time of appearance and the perseverance of the inflammatory process with E-Selectin and VCAM-1 expression was observed, but not with PECAM-1. The strain with a higher pathogenicity was able to invade deep vaginal tissues and thus, parasites could not be detected by vaginal washings. This may be an important cause of diagnosis and treatment failure. Also, by the different localization of trichomonads, it appeared that the battle between host and parasite took place in different areas dependent upon the characteristics of the strain.

Metronidazole resistance in Trichomonas vaginalis from highland women in Papua New Guinea

BACKGROUND

The prevalence of the sexually transmissible protozoan parasite Trichomonas vaginalis in the highlands of Papua New Guinea (PNG) has been reported to be as high as 46% and although not previously studied in Papua New Guinea, clinical resistance against metronidazole (Mz), the drug most commonly used to treat trichomoniasis, is well documented worldwide. This study was primarily aimed at assessing resistance to Mz in T. vaginalis strains from the Goroka region.

METHODS

Consenting patients presenting at the Goroka Base Hospital Sexually Transmitted Diseases (STD) Clinic and local women were asked to provide two vaginal swabs: one for culturing of the parasite; and one for polymerase chain reaction detection of T. vaginalis, Chlamydia trachomatis and Neisseria gonorrhoeae. T. vaginalis isolates were assayed for Mz susceptibility and a selection was genotyped.

RESULTS

The prevalence of T. vaginalis was determined to be 32.9% by culture and polymerase chain reaction of swabs among 82 local women and patients from the STD clinic. An unexpectedly high level of in vitro Mz resistance was determined with 17.4% of isolates displaying unexpectedly high resistance to Mz. The ability to identify isolates of T. vaginalis by genotyping was confirmed and the results revealed a more homogeneous T. vaginalis population in Papua New Guinea compared with isolates from elsewhere.

CONCLUSION

T. vaginalis is highly prevalent in the Goroka region and in vitro Mz resistance data suggest that clinical resistance may become an issue.

Identification of two novel Trichomonas vaginalis eif-5a genes

The eukaryotic translation initiation factor 5A (eIF-5A) is highly conserved and is the only protein that is known to contain the unique and essential amino acid residue hypusine. Synthesis of hypusine is essential for the function of eIF5A in eukaryotic cell proliferation and survival. In this study, we identified two novel eukaryotic translation initiation factor 5A (eIF-5A) genes in Trichomonas vaginalis. The tveif-5a1 and tveif-5a2 putative genes were localized in different contigs, both containing ORFs encoding proteins of 168 amino acids that share high sequence identity with eIF-5A sequences from other eukaryotic organisms. A phylogenetic tree constructed with TveIF-5A1 and TveIF-5A2 from T. vaginalis and 13 other eIF-5A sequences of eukaryotic and archaebacterial origin revealed that both trichomonal TveIF-5As show the highest degree of similarity to bacteria. Using an anti-TveIF-5A antibody, we detected two protein bands and spots of 19 and 20kDa with isoelectric points (pI) of 5.2 and 5.5, respectively, by one and two-dimensional Western blot assays. In addition, we used reverse transcription polymerase chain reaction (RT-PCR) to demonstrate that both of these tveif-5a genes are expressed in T. vaginalis. Immunofluorescence assays showed that the TveIF-5A protein was dispersed throughout the parasite cytoplasm. In conclusion, T. vaginalis has two eif-5a genes, and both genes are expressed as highly conserved proteins of 19kDa, which are localized in the cytoplasm of this parasite.

Trichomonas vaginalis nucleoside triphosphate diphosphohydrolase and ecto-5'-nucleotidase activities are inhibited by lycorine and candimine

Drug discovery from plants plays an important role in the pharmaceutical therapy field and the alkaloids lycorine and candimine are candidates for this purpose. Trichomonas vaginalis is a parasite that infects the human urogenital tract and causes trichomonosis, the most prevalent non-viral sexually transmitted disease. Ecto-nucleotidases including nucleoside triphosphate diphosphohydrolase (NTPDase) members, which hydrolyses extracellular ATP (adenosine triphosphate) and ADP (adenosine diphosphate), and ecto-5'-nucleotidase, which hydrolyses AMP (adenosine monophosphate), have been characterized in T. vaginalis. Because purine nucleotides are released from cells under physiological and stress conditions, the goal of this study was to evaluate the effect of lycorine and candimine on T. vaginalis NTPDase and ecto-5'-nculeotidase activities. The alkaloids (50 to 250microM) were tested against both long-term-grown and clinical isolates. Specific enzymatic activities were expressed as nmolPi released/min/mg protein. The effect of both alkaloids at NTPDase A and B expression levels was investigated. When the alkaloids were added directly to the reaction mixture, no effect on ATP, ADP or AMP hydrolysis was observed. NTPDase and ecto-5'-nucleotidase activities were strongly inhibited by candimine and lycorine on 24h-treated parasites. This effect was abolished when 24-treated parasites were innoculated in a culture medium without alkaloid. Transcript levels of NTPDase A or B were not altered by the alkaloids. Considering the cytotoxic and proinflammatory roles of ATP besides the anti-inflammatory effects of adenosine, the regulation of extracellular nucleotide levels could be relevant in increasing susceptibility of T. vaginalis to host immune response in the presence of lycorine and candimine.

Trichomonas vaginalis: dehydroepiandrosterone sulfate and 17beta-estradiol alter NTPDase activity and gene expression

We investigated the effect of dehydroepiandrosterone sulfate (DHEAS) and 17beta-estradiol on NTPDase activity in fresh clinical (VP60) and long-term-grown (30236 ATCC) isolates of Trichomonas vaginalis followed by NTPDase gene transcriptional analysis. ATP hydrolysis was activated in vitro by 17beta-estradiol (0.01-1.0microM) in the VP60 isolate. Treatment for 2h with 17beta-estradiol (0.01-1microM) promoted an inhibition in nucleotide hydrolysis in the 30236 isolate whereas the 12h-treatment promoted an activation of nucleotide hydrolysis in both isolates. ADP hydrolysis was inhibited in vitro by 1.0-5.0microM DHEAS in the ATCC isolate. The treatment with DHEAS (0.01-1.0microM) for 2h inhibited ATP and ADP hydrolysis in VP60; however, during a 12h-treatment with DHEAS, nucleotide hydrolysis was inhibited in both isolates. Two NTPDase orthologous (NTPDaseA and NTPDaseB) were identified and the treatment with DHEAS for 12h was able to inhibit mRNA NTPDaseA transcript levels from the VP60. These findings demonstrate that NTPDase activity and gene expression pattern are modulated by exposure to steroids in T. vaginalis.

Estimates of the direct cost per case and overall burden of trichomoniasis for the employer-sponsored privately insured women population in the United States, 2001 to 2005

BACKGROUND

Little is known about the direct medical cost and overall burden of trichomoniasis among women in the United States.

METHODS

We extracted insurance claims for trichomoniasis for 2001 to 2005 from the MEDSTAT MarketScan database using International Classification of Diseases, ninth revision codes. The analysis was restricted to outpatient care and prescription drug claims for women in 4 age categories; under 15, 15 to 24, 25 to 34, and 35 to 64. We used Current Procedures Terminology codes to analyze diagnostic methodologies. All costs were adjusted to 2005 US dollars.

RESULTS

The average outpatient and prescription drug costs per episode for all ages were 97 dollars and 9 dollars, respectively. The resulting average total cost per episode was 101 dollars (about 50% did not have drug costs). Average total cost among women aged 15 to 24 years (120 dollars) was significantly (P < 0.01) higher than all other age categories. The estimated annual economic burden was 6.8 million dollars among privately insured women and 18.9 million dollars among all women from the United States. The incidence rate for female enrollees (all ages) having claims was 91 per 100,000 enrollees. Incidence rates were highest for women aged 25 to 29 years (185 per 100,000), followed by women aged 20 to 24 years (166 per 100,000). The most common diagnostic procedure seemed to be wet mount, but nonspecificity of Current Procedures Terminology codes inhibited the analysis of diagnostic methodologies.

CONCLUSION

The estimated economic burden was highest among reproductive age women (15-34 years). Our estimated economic burden represents a lower-bound estimate because it was based on direct medical costs only.

Steroid hormones alter AMP hydrolysis in intact trophozoites of Trichomonas vaginalis

Trichomonas vaginalis infection may be influenced by the vaginal concentrations of estrogens. We have investigated the effects of 17beta-estradiol and dehydroepiandrosterone sulfate (DHEAS) on the ecto-5'-nucleotidase activity in fresh clinical (VP60) and in long-term-grown (30236 ATCC) isolates of T. vaginalis. In vitro exposure to DHEAS and 17beta-estradiol did not induce any changes in adenosine monophosphate (AMP) hydrolysis in these isolates. The treatment of parasites in the presence of DHEAS (0.01-1.0 microM) for 2 h inhibited AMP hydrolysis in VP60 isolate, whereas there were no significant changes in nucleotide hydrolysis in the presence of 17beta-estradiol. DHEAS and 17beta-estradiol (0.01-1.0 microM) for 2 h inhibited AMP hydrolysis in 30236 isolate. The 12 treatment with 0.1 microM DHEAS inhibited AMP hydrolysis, whereas 17beta-estradiol did not alter the nucleotide hydrolysis in VP60 isolate. Our findings have shown that the complex effect of steroid hormones and their receptors on T. vaginalis may promote changes in ecto-5'-nucleotidase activity during exposure to these hormones.