Circadian clock genes and respiratory neuroplasticity genes oscillate in the phrenic motor system.

Circadian rhythms are endogenous and entrainable daily patterns of physiology and behavior. Molecular mechanisms underlie circadian rhythms, characterized by an ~24-h pattern of gene expression of core clock genes. Although it has long been known that breathing exhibits circadian rhythms, little is known concerning clock gene expression in any element of the neuromuscular system controlling breathing. Furthermore, we know little concerning gene expression necessary for specific respiratory functions, such as phrenic motor plasticity. Thus, we tested the hypotheses that transcripts for clock genes (Bmal1, Clock, Per1, and Per2) and molecules necessary for phrenic motor plasticity (Htr2a, Htr2b, Bdnf, and Ntrk2) oscillate in regions critical for phrenic/diaphragm motor function via RT-PCR. Tissues were collected from male Sprague-Dawley rats entrained to a 12-h light-dark cycle at 4 zeitgeber times (ZT; n = 8 rats/group): ZT5, ZT11, ZT17, and ZT23; ZT0 = lights on. Here, we demonstrate that 1) circadian clock genes (Bmal1, Clock, Per1, and Per2) oscillate in regions critical for phrenic/diaphragm function, including the caudal medulla, ventral C3-C5 cervical spinal cord, and diaphragm; 2) the clock protein BMAL1 is localized within CtB-labeled phrenic motor neurons; 3) genes necessary for intermittent hypoxia-induced phrenic/diaphragm motor plasticity (Htr2b and Bdnf) oscillate in the caudal medulla and ventral C3-C5 spinal cord; and 4) there is higher intensity of immunofluorescent BDNF protein within phrenic motor neurons at ZT23 compared with ZT11 (n = 11 rats/group). These results suggest local circadian clocks exist in the phrenic motor system and confirm the potential for local circadian regulation of neuroplasticity and other elements of the neural network controlling breathing.

Targeted transgenesis identifies Gαs as the bottleneck in ß2-adrenergic receptor cell signaling and physiological function in airway smooth muscle.

G protein-coupled receptors are the most pervasive signaling superfamily in the body and act as receptors to endogenous agonists and drugs. For ß-agonist-mediated bronchodilation, the receptor-G protein-effector network consists of the ß2-adrenergic receptor (ß2AR), Gs, and adenylyl cyclase, expressed on airway smooth muscle (ASM). Using ASM-targeted transgenesis, we previously explored which of these three early signaling elements represents a limiting factor, or bottleneck, in transmission of the signal from agonist binding to ASM relaxation. Here we overexpressed Gαs in transgenic mice and found that agonist-promoted relaxation of airways was enhanced in direct proportion to the level of Gαs expression. Contraction of ASM from acetylcholine was not affected in Gαs transgenic mice, nor was relaxation by bitter taste receptors. Furthermore, agonist-promoted (but not basal) cAMP production in ASM cells from Gαs-transgenic mice was enhanced compared with ASM from nontransgenic littermates. Agonist-promoted inhibition of platelet-derived growth factor-stimulated ASM proliferation was also enhanced in Gαs mouse ASM. The enhanced maximal ß-agonist response was of similar magnitude for relaxation, cAMP production, and growth inhibition. Taken together, it appears that a limiting factor in ß-agonist responsiveness in ASM is the expression level of Gαs. Gene therapy or pharmacological means of increasing Gαs (or its coupling efficiency to ß2AR) thus represent an interface for development of novel therapeutic agents for improvement of ß-agonist therapy.

The use of quantitative clinical pharmacology approaches to support moxidectin dosing recommendations in lactation.

Moxidectin is approved by the US Food and Drug Administration (US FDA) for the treatment of onchocerciasis (river-blindness) due to Onchocerca volvulus in patients aged 12 years and older. In onchocerciasis-endemic areas, mass drug administration (MDA) programs with ivermectin, with or without vector control, aim to control the disease, reduce morbidity, interrupt transmission, and more recently, achieve elimination. Moxidectin has the potential to be used in MDA programs. In countries where onchocerciasis is endemic, infants are often breastfed up to the age of 2 years, suggesting that some women are likely to be lactating during such periodic MDA programs. Quantitative analyses of non-clinical and clinical data using non-compartmental analysis and population based pharmacokinetic (popPK) modeling as well as physiologically based pharmacokinetic modeling (PBPK) were performed to determine the amount of moxidectin excreted in breast milk and subsequent exposures in the infant. The results of the analyses were similar. Concentrations of moxidectin in breast milk followed a similar pattern to those in plasma, with maximum concentrations occurring approximately 4 hours after dosing followed by a rapid decline in both breast milk and plasma. As early as two days after dosing, concentrations of moxidectin in breast milk were below the threshold for acceptable daily intake levels established by the European Medicines Agency (EMA) and FDA for secondary exposures from veterinary use, and below the WHO recommended relative infant dose (RID) safety threshold. The analyses were conducted to support prescribers and policy makers on dosing recommendations for moxidectin in lactation.

Male circumcision and prevalence of genital human papillomavirus infection in men: a multinational study.

BACKGROUND: Accumulated evidence from epidemiological studies and more recently from randomized controlled trials suggests that male circumcision (MC) may substantially protect against genital HPV infection in men. The purpose of this study was to assess the association between MC and genital HPV infection in men in a large multinational study. METHODS: A total of 4072 healthy men ages 18-70 years were enrolled in a study conducted in Brazil, Mexico, and the United States. Enrollment samples combining exfoliated cells from the coronal sulcus, glans penis, shaft, and scrotum were analyzed for the presence and genotyping of HPV DNA by PCR and linear array methods. Prevalence ratios (PR) were used to estimate associations between MC and HPV detection adjusting for potential confounders. RESULTS: MC was not associated with overall prevalence of any HPV, oncogenic HPV types or unclassified HPV types. However, MC was negatively associated with non-oncogenic HPV infections (PR 0.85, 95% confident interval: 0.76-0.95), in particular for HPV types 11, 40, 61, 71, and 81. HPV 16, 51, 62, and 84 were the most frequently identified genotypes regardless of MC status. CONCLUSIONS: This study shows no overall association between MC and genital HPV infections in men, except for certain non-oncogenic HPV types for which a weak association was found. However, the lack of association with MC might be due to the lack of anatomic site specific HPV data, for example the glans penis, the area expected to be most likely protected by MC.

Genital human papillomavirus (HPV) concordance in heterosexual couples.

BACKGROUND: Few studies have assessed genital human papillomavirus (HPV) concordance and factors associated with concordance among asymptomatic heterosexual couples. METHODS: Genotyping for HPV was conducted with male and female sex partners aged 18-70 years from Tampa, Florida. Eligibility included no history of HPV-associated disease. Type-specific positive concordance (partners with ≥ 1 genotype in common) and negative concordance (neither partner had HPV) were assessed for 88 couples. Factors associated with concordance were assessed with Fisher exact tests and tests for trend. RESULTS: Couples reported engaging in sexual intercourse for a median of 1.7 years (range, 0.1-49 years), and 75% reported being in the same monogamous relationship for the past 6 months. Almost 1 in 4 couples had type-specific positive concordance, and 35% had negative concordance for all types tested, for a total concordance of 59%. Concordance was not associated with monogamy. Type-specific positive concordance was associated with an increasing difference in partners' lifetime number of sex partners and inversely associated with an increasing difference in age. Negative concordance was inversely associated with both the couple's sum of lifetime number of sex partners and the difference in the partners' lifetime number of sex partners. CONCLUSIONS: Genital HPV concordance was common. Viral infectiousness and number of sex partners may help explain concordance among heterosexual partners.

Race and prevalence of human papillomavirus infection among men residing in Brazil, Mexico and the United States.

Human papillomavirus (HPV) causes anal, penile and oropharyngeal cancers in men. Genital HPV prevalence in men appears to vary by world region with men residing in Asia having among the lowest prevalence. Unfortunately, there is little information on prevalence of HPV infection in men by race. The purpose of this study was to examine HPV prevalence by race across three countries. 3,909 men ages 18-70 years enrolled in an ongoing prospective cohort study of the natural history of HPV in men (The HIM Study) were included in the analysis. Participants completed risk factor questionnaires and samples were taken from the penile epithelium and scrotum for HPV detection. HPV testing of the combined DNA extract was conducted using PCR and genotyping. Asian/Pacific Islanders had the lowest HPV prevalence of 42.2% compared to Blacks (66.2%), and Whites (71.5%). The Asian/Pacific Islander race was strongly protective in univariate analysis (prevalence ratio (PR) = 0.59; 95% confidence interval (CI): 0.48-0.74) and multivariate analysis for any HPV infection (PR = 0.65; 95% CI: 0.52-0.8). Stratified analysis by lifetime number of female partners also showed strong inverse associations with the Asian/Pacific Islander race. We consistently observed the lowest prevalence of HPV infection among Asian/Pacific Islanders with moderate inverse associations even after various adjustments for potential confounding factors. Unmeasured behavioral factors, sexual mixing with low risk women, and/or race-specific differences in the frequency of germline variations among immune regulating genes may underlie these associations. Further studies among Asian populations that incorporate measures of immuno-genetics are needed to understand this phenomenon.

Incidence and clearance of genital human papillomavirus infection in men (HIM): a cohort study.

BACKGROUND: Human papillomaviruses (HPVs) cause genital warts and cancers in men. The natural history of HPV infection in men is largely unknown, and that information is needed to inform prevention strategies. The goal in this study was to estimate incidence and clearance of type-specific genital HPV infection in men, and to assess the associated factors. METHODS: Men (aged 18-70 years), residing in Brazil, Mexico, and the USA, who were HIV negative and reported no history of cancer were recruited from the general population, universities, and organised health-care systems. They were assessed every 6 months for a median follow-up of 27·5 months (18·0-31·2). Specimens from the coronal sulcus, glans penis, shaft, and scrotum were obtained for the assessment of the status of HPV genotypes. FINDINGS: In 1159 men, the incidence of a new genital HPV infection was 38·4 per 1000 person months (95% CI 34·3-43·0). Oncogenic HPV infection was significantly associated with having a high number of lifetime female sexual partners (hazard ratio 2·40, 1·38-4·18, for at least 50 partners vs not more than one partner), and number of male anal-sexual partners (2·57, 1·46-4·49, for at least three male partners vs no recent partners). Median duration of HPV infection was 7·52 months (6·80-8·61) for any HPV and 12·19 months (7·16-18·17) for HPV 16. Clearance of oncogenic HPV infection decreased in men with a high number of lifetime female partners (0·49, 0·31-0·76, for at least 50 female partners vs not more than one partner), and in men in Brazil (0·71, 0·56-0·91) and Mexico (0·73, 0·57-0·94) compared with the USA. Clearance of oncogenic HPV was more rapid with increasing age (1·02, 1·01-1·03). INTERPRETATION: The data from this study are useful for the development of realistic cost-effectiveness models for male HPV vaccination internationally. FUNDING: National Cancer Institute.

Clustering of human papillomavirus (HPV) types in the male genital tract: the HPV in men (HIM) study.

OBJECTIVE: To evaluate clustering patterns of prevalent infection with multiple human papillomavirus (HPV) types in 3677 men from the HPV in Men (HIM) study. METHODS: HPV testing was performed in samples combined from the glans penis/coronal sulcus, the shaft, and the scrotum by Linear Array methodology. Linear Array uses a mixed probe to assess HPV52 positivity, which limits the assay's ability to determine HPV52 status in the presence of HPV33, 35, or 58. Logistic regression was used to model type-specific HPV positivity, adjusted for age, study area, lifetime number of sexual partners, and specific HPV type prevalence. Participant-level random effects were added to represent unobservable risk factors common to all HPV types. RESULTS: The observed-to-expected ratio for infections with ≥ 3 types was 1.09 (95% credible interval, 1.04-1.14). For the majority of 2-type combinations, no evidence was found of a significant departure of the observed from the expected number. An apparent clustering of HPV52 with HPV35 or 58 was observed, because of limitation in the ability of Linear Array to define HPV52 positivity. CONCLUSIONS: Our study showed that, despite obvious anatomical differences, HPV coinfections do seem to occur at random in the male external genitalia as in the female cervix.

Age-specific prevalence of and risk factors for anal human papillomavirus (HPV) among men who have sex with women and men who have sex with men: the HPV in men (HIM) study.

BACKGROUND: An increasing incidence of anal cancer among men suggests a need to better understand anal canal human papillomavirus (HPV) infection among human immunodeficiency virus-negative men. METHODS: Genotyping for HPV was conducted on cells from the anal canal among men who have sex with women (MSW) and men who have sex with men (MSM), aged 18-70 years, from Brazil, Mexico, and the United States. Factors associated with anal HPV infection were assessed using multivariable logistic regression. RESULTS: The prevalence of any HPV type and oncogenic HPV types did not differ by city. Anal canal HPV prevalence was 12.2% among 1305 MSW and 47.2% among 176 MSM. Among MSW, reporting a lifetime number of ≥ 10 female sex partners, a primary sexual relationship <1 year in duration, and a prior hepatitis B diagnosis were independently associated with detection of any anal HPV in multivariable analysis. Among MSM, a younger age, reporting ≥ 2 male anal sex partners in the past 3 months, and never using a condom for anal sex in the past 6 months were independently associated with detection of any anal HPV in multivariable analysis. CONCLUSIONS: Number of sex partners was associated with anal HPV infection in both MSW and MSM. Anal HPV infection in men may be mediated by age, duration of sexual relationship, and condom use.

Six-month incidence, persistence, and factors associated with persistence of anal human papillomavirus in men: the HPV in men study.

BACKGROUND: Although there are limited numbers of incidence and persistence estimates for anal human papillomavirus (HPV) in women and in men who have sex with men (MSM), there are no such reports for men who have sex with women (MSW). METHODS: Genotyping was performed on anal samples from men, aged 18-70, from São Paulo, Brazil; Cuernavaca, Mexico; and Tampa, Florida, who provided specimens at enrollment and the 6-month visit of a 4-year prospective study. Eligibility included no history of genital warts or human immunodeficiency virus. A total of 954 MSW and 156 MSM provided evaluable specimens at both visits. Persistence was defined as type-specific infection at each visit. RESULTS: Incident anal infection was common among both MSM and MSW but generally higher for MSM for HPV groups and specific genotypes. A total of 5.1% of MSM and 0.0% of MSW had a persistent HPV-16 infection at the 6-month visit. Cigarette smoking among MSM and age among MSW were associated with persistent infection with any HPV genotype. CONCLUSIONS: Although anal HPV infection is commonly acquired by both MSW and MSM, incident events and persistence occurred more often among MSM. Cigarette smoking is a modifiable risk factor that may contribute to HPV persistence among MSM.

The prevalence of genital HPV and factors associated with oncogenic HPV among men having sex with men and men having sex with women and men: the HIM study.

BACKGROUND: Comparative studies of genital human papillomavirus (HPV) among men having sex with men (MSM), men having sex with women and men (MSWM), and men having sex with women (MSW) have not been conducted so far; however, such comparisons may be important for planning prevention strategies like vaccination. METHODS: Men, aged 18 to 70 years, were enrolled in a study of genital HPV in São Paulo, Brazil; Cuernavaca, Mexico; and Tampa, FL. Men were classified as MSM (n = 170), MSWM (n = 214), and MSW (n = 3326) based on self-reported sexual behavior. Genotyping for HPV was conducted on cells from the penis and scrotum. Prevalence data were adjusted by country. Factors potentially associated with genital HPV were assessed using multivariable Poisson regression. RESULTS: Genital HPV prevalence was typically higher among MSWM than among MSM or MSW for groups of HPV genotypes including nononcogenic types (51%, 36%, and 42%, respectively), and multiple types (37%, 24%, and 29%, respectively). Age and alcohol consumption in the past month were associated with oncogenic HPV among both MSM and MSWM; however, there were no statistically significant associations between sexual behaviors and genital HPV among MSM or MSWM. CONCLUSIONS: Prevalence of genital HPV may be higher among MSWM than among MSW or MSM. Number of female sex partners was associated with genital HPV among MSW, but number of male anal sex partners was not associated with genital HPV among MSM and MSWM.

Prevalence of and risk factors for anal human papillomavirus infection in men who have sex with women: a cross-national study.

BACKGROUND: Although the primary cause of anal cancer is human papillomavirus (HPV) infection in the anal canal, little attention has been paid to the epidemiology of anal HPV infection in men who have sex with women (MSW). METHODS: Exfoliated cells from the anal canal of 902 MSW in Brazil (São Paulo), Mexico (Cuernavaca), and the United States (Tampa) were tested for HPV DNA. RESULTS: The prevalence of HPV infection in the anal canal (12.0%) was similar among MSW in each city (P=.77), whereas 7.0% had infection with oncogenic types. Men in Tampa had a 4-fold higher prevalence of infection with HPV type 16 (HPV-16) than that among men in São Paulo or Cuernavaca (P<.001). Duration of relationship with a primary sex partner and ever having oral or anal sex with a man was associated with infection with any HPV type and with any oncogenic type, whereas lifetime number of female sex partners was associated with infection with any HPV type. CONCLUSIONS: Anal canal HPV infection is commonly found among MSW, and the prevalence of infection with HPV-16 may differ substantially by geography. Men who have a larger lifetime number of female sex partners, who are in a sexual relationship of <1 year in duration, and who have a history of oral or anal sex with men were most likely to have an anal HPV infection.

Using gene expression profiling to differentiate benign versus malignant thyroid tumors.

DNA microarrays allow quick and complete evaluation of a cell's transcriptional activity. Expression genomics is very powerful in that it can generate expression data for a large number of genes simultaneously across multiple samples. In cancer research, an intriguing application of expression arrays includes assessing the molecular components of the neoplastic process and utilizing the data for cancer classification (Miller LD, et al. Cancer Cell 2002;2:353-61). Classification of human cancers into distinct groups based on their molecular profile rather than their histological appearance may prove to be more relevant to specific cancer diagnoses and cancer treatment regimes. Several attempts to formulate a consensus about classification and treatment of thyroid carcinoma based on standard histopathological analysis have resulted in published guidelines for diagnosis and initial disease management (Sherman SI. Lancet 2003;361:501-11). In the past few decades, no improvement has been made in the differential diagnosis of thyroid tumors by fine needle aspiration biopsy, specifically suspicious or indeterminate thyroid lesions, suggesting that a new approach to this should be explored. Therefore, in this study, we developed a gene expression approach to diagnose benign versus malignant thyroid lesions in 73 patients with thyroid tumors. We successfully built a 10 and 6 gene model able to differentiate benign versus malignant thyroid tumors. Our results support the premise that a molecular classification system for thyroid tumors is possible, and this in turn may provide a more accurate diagnostic tool for the clinician managing patients with suspicious thyroid lesions.

Human telomerase reverse transcriptase gene expression and the surgical management of suspicious thyroid tumors.

PURPOSE: Patients with a preoperative cytologic diagnosis of a suspicious thyroid nodule present a therapeutic dilemma because surgery differs for benign and malignant lesions. To address this issue, several molecular markers, including human telomerase reverse transcriptase (TERT), have been tested as markers of thyroid cancer. Because most studies select cases falling into well-defined categories to test new markers, they may overestimate their discriminatory power when applied to samples that are difficult to classify. Fine-needle aspirates (FNAs) of the thyroid with indeterminate cytology are an example of such cases. EXPERIMENTAL DESIGN: We examined whether assessing TERT mRNA by reverse transcription-PCR could have improved the surgical management in a cohort of 100 patients undergoing thyroidectomy for indeterminate FNA results. RESULTS: Ninety percent of 48 cancers were TERT positive, as were 35% of 52 benign lesions. When 10 cases with concomitant lymphocytic thyroiditis were excluded, the overall sensitivity of TERT was 91% (95% confidence interval, 80-98%) and specificity was 79% (64-90%). No clinical or tumor variable contributed to the predictive ability of TERT except for tumor size, which added only marginally. Basing the surgical approach on the TERT assay alone would have reduced lobectomies performed for malignant disease from 11 to 4 cases and reduced total thyroidectomies for benign lesions from to 15 to 9, an overall 50% reduction in suboptimal treatment. CONCLUSIONS: The overall performance of preoperative differential diagnosis for thyroid tumors with indeterminate FNA results can be substantially improved by the inclusion of molecular markers such as TERT.

Pleiotropic Effects of Bitter Taste Receptors on [Ca2+]i Mobilization, Hyperpolarization, and Relaxation of Human Airway Smooth Muscle Cells.

Asthma is characterized by airway inflammation and airflow obstruction from human airway smooth muscle (HASM) constriction due to increased local bronchoconstrictive substances. We have recently found bitter taste receptors (TAS2Rs) on HASM, which increase [Ca2+]i and relax the muscle. We report here that some, but not all, TAS2R agonists decrease [Ca2+]i and relax HASM contracted by G-protein coupled receptors (GPCRs) that stimulate [Ca2+]i. This suggests both a second pathway by which TAS2Rs relax, and, a heterogeneity of the response phenotype. We utilized eight TAS2R agonists and five procontractile GPCR agonists in cultured HASM cells. We find that heterogeneity in the inhibitory response hinges on which procontractile GPCR is activated. For example, chloroquine inhibits [Ca2+]i increases from histamine, but failed to inhibit [Ca2+]i increases from endothelin-1. Conversely, aristolochic acid inhibited [Ca2+]i increases from endothelin-1 but not histamine. Other dichotomous responses were found when [Ca2+]i was stimulated by bradykinin, angiotensin, and acetylcholine. There was no association between [Ca2+]i inhibition and TAS2R subtype, nor whether [Ca2+]i was increased by Gq- or Gi-coupled GPCRs. Selected studies revealed a correlation between [Ca2+]i inhibition and HASM cell-membrane hyperpolarization. To demonstrate physiologic correlates, ferromagnetic beads were attached to HASM cells and cell stiffness measured by magnetic twisting cytometry. Consistent with the [Ca2+]i inhibition results, chloroquine abolished the cell stiffening response (contraction) evoked by histamine but not by endothelin-1, while aristolochic acid inhibited cell stiffening from endothelin-1, but not from histamine. In studies using intact human bronchi, these same differential responses were found. Those TAS2R agonists that decreased [Ca2+]i, promoted hyperpolarization, and decreased HASM stiffness, caused relaxation of human airways. Thus TAS2Rs relax HASM in two ways: a low-efficiency de novo [Ca2+]i stimulation, and, a high-efficiency inhibition of GPCR-stimulated [Ca2+]i. Furthermore, there is an interaction between TAS2Rs and some GPCRs that facilitates this [Ca2+]i inhibition limb.

Seroprevalence of human papillomavirus (HPV) type 6 and 16 vary by anatomic site of HPV infection in men.

BACKGROUND: It is largely unknown if antihuman papillomavirus (HPV) serum antibody responses vary by anatomic site of infection in men. METHODS: This study assessed type-specific anti-HPV serum antibody prevalence associated with corresponding HPV DNA detection in the external genitalia and the anal canal of 1,587 heterosexual men and 199 men who have sex with men (MSM). RESULTS: We observed that HPV 6 and 16 seroprevalence was higher in the presence of same HPV-type infection in the anal canal compared with same HPV-type infection in the external genitalia only, and among MSM compared with the heterosexual men. Seropositivity to HPV 6 was strongly associated with HPV 6 DNA detection in the anal canal but not in the external genitalia alone among both heterosexual men [adjusted prevalence ratio (APR), anal+/genital+ vs. anal-/genital-: 4.2, 95% confidence interval (CI), 11.7-10.5; anal+/genital- vs. anal-/genital-: 7.9 (95% CI, 3.7-17.0)] and MSM [APR, anal+/genital+ vs. anal-/genital-: 5.6 (95% CI, 2.7-11.9); anal+/genital- vs. anal-/genital-: 3.2 (95% CI, 2.1-4.9)]. Similar associations between seropositivity to HPV 16 and anal HPV 16 DNA detection were only observed in MSM [anal+/genital+ vs. anal-/genital-: 3.1 (95% CI, 2.0-5.0); anal+/genital- vs. anal-/genital-: 2.2 (95% CI, 1.3-3.5)]. CONCLUSION: Our data showed that seroprevalence varied by anatomic site of HPV infection, suggesting differences in epithelium type present at these anatomic sites may be relevant. IMPACT: Our finding is instrumental in advancing our understanding of immune mechanism involved in anatomic site-specific antibody response.

Prevalent serum antibody is not a marker of immune protection against acquisition of oncogenic HPV16 in men.

In women, naturally induced anti-human papilloma virus (HPV) serum antibodies are a likely marker of host immune protection against subsequent HPV acquisition and progression to precancerous lesions and cancers. However, it is unclear whether the same is the case in men. In this study, we assessed the risk of incident genital infection and 6-month persistent genital infection with HPV16 in relation to baseline serostatus in a cohort of 2,187 men over a 48-month period. Genital swabs were collected every 6 months and tested for HPV presence. Incidence proportions by serostatus were calculated at each study visit to examine whether potential immune protection attenuated over time. Overall, incidence proportions did not differ statistically between baseline seropositive and seronegative men at any study visit or over the follow-up period. The risk of incident and 6-month persistent infection was not associated with baseline serostatus or baseline serum antibody levels in the cohort. Our findings suggest that baseline HPV seropositivity in men is not associated with reduced risk of subsequent HPV16 acquisition. Thus, prevalent serum antibodies induced by prior infection may not be a suitable marker for subsequent immune protection against genital HPV16 acquisition in men.

The epidemiology of oral HPV infection among a multinational sample of healthy men.

BACKGROUND: Oral human papillomavirus type-16 (HPV16) infection is a risk factor for oropharyngeal cancer. We examined oral HPV infection among healthy men. METHODS: Oral rinse/gargle specimens and questionnaire data were collected from 1,688 healthy men aged 18 to 74 (median = 31 years), from the United States, Mexico, and Brazil. HPV16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58 and 59, and noncarcinogenic HPV types were detected using Roche Linear Array. RESULTS: Oral HPV DNA was detected in 67 of 1,680 (4.0%, 95% CI = 3.1%-5.0%) ß-globin-positive specimens; carcinogenic HPVs were detected in 1.3% (95% CI = 0.8%-2.0%; n = 22) and HPV16 was the most commonly detected carcinogenic HPV type (0.6%, 95% CI = 0.2%-1.1%; n = 10). The prevalence of oral HPV infection was similar by country except for HPV55, which had notably higher prevalence in Mexico (3.0%) than Brazil (0%) or the United States (0.2%). Oral HPV prevalence nonsignificantly increased over increasing age categories (P(trend) = 0.096). The strongest predictor of oral HPV was current tobacco use, which increased the odds 2.5-fold (95% CI = 1.4-4.4). Oral sexual behaviors were not associated with oral HPV infection. CONCLUSIONS: Oral HPV16 infection was rare in healthy men, especially at younger ages, and was positively associated with current tobacco use. IMPACT: Oral HPV appears to be about 10-fold less prevalent than infection at genital sites in men (4% vs. ∼40%, respectively). It remains unclear whether this reflects reduced exposure or if the oral region is more resistant to HPV infection compared with anogenital sites.

Human papillomavirus (HPV) 6, 11, 16, and 18 seroprevalence is associated with sexual practice and age: results from the multinational HPV Infection in Men Study (HIM Study).

BACKGROUND: Few human papillomavirus (HPV) serology studies have evaluated type-specific seroprevalence of vaccine HPV types in men. This study investigates seroprevalence of HPV 6, 11, 16, and 18, and associated risk factors in men residing in three countries (United States, Mexico, and Brazil). METHODS: Data from 1,477 men aged 18 to 70 enrolled in the HPV Infection in Men Study (HIM Study) were analyzed. Serum antibody testing was performed with virus-like particle-based ELISA. Potential risk factors were assessed for individual HPV types by the use of logistic regression. RESULTS: Overall, HPV-6, 11, 16, and 18 seroprevalence was 14.8%, 17.3%, 11.2%, and 5.8%, respectively. Thirty-four percent of men were seropositive to one or more HPV types. When examined by sexual practice, 31.2% of men who had sex with women, 65.6% of men who had sex with men (MSM), and 59.4% of men who had sex with both men and women (MSMW) were seropositive to one or more HPV types. Seroprevalence increased with age among young-to-middle-aged men with significant upward age trends observed for HPV 11, 16, and 18. Men with multiple lifetime male anal sex partners were 2 to 4 times more likely to be HPV 6 or 11 seropositive and 3 to 11 times more likely to be HPV 16 or 18 seropositive. CONCLUSION: Our data indicate that exposures to vaccine HPV types were common in men and highly prevalent among MSM and MSMW. IMPACT: Our study provides strong evidence that the practice of same-sex anal intercourse is an independent risk factor for seroprevalence of individual vaccine HPV types. Examination of antibody responses to HPV infections at various anatomic sites in future studies is needed to elaborate on the mechanism.

The optimal anatomic sites for sampling heterosexual men for human papillomavirus (HPV) detection: the HPV detection in men study.

Background. Human papillomavirus (HPV) infection in men contributes to infection and cervical disease in women as well as to disease in men. This study aimed to determine the optimal anatomic site(s) for HPV detection in heterosexual men.Methods. A cross-sectional study of HPV infection was conducted in 463 men from 2003 to 2006. Urethral, glans penis/coronal sulcus, penile shaft/prepuce, scrotal, perianal, anal canal, semen, and urine samples were obtained. Samples were analyzed for sample adequacy and HPV DNA by polymerase chain reaction and genotyping. To determine the optimal sites for estimating HPV prevalence, site-specific prevalences were calculated and compared with the overall prevalence. Sites and combinations of sites were excluded until a recalculated prevalence was reduced by <5% from the overall prevalence.Results. The overall prevalence of HPV was 65.4%. HPV detection was highest at the penile shaft (49.9% for the full cohort and 47.9% for the subcohort of men with complete sampling), followed by the glans penis/coronal sulcus (35.8% and 32.8%) and scrotum (34.2% and 32.8%). Detection was lowest in urethra (10.1% and 10.2%) and semen (5.3% and 4.8%) samples. Exclusion of urethra, semen, and either perianal, scrotal, or anal samples resulted in a <5% reduction in prevalence.Conclusions. At a minimum, the penile shaft and the glans penis/coronal sulcus should be sampled in heterosexual men. A scrotal, perianal, or anal sample should also be included for optimal HPV detection.