RNA-based drugs are an emerging class of therapeutics. They have the potential to regulate proteins, chromatin, as well as bind to specific proteins of interest in the form of aptamers. These ...aptamers are protected from nuclease attack by chemical modifications that enhance their stability for in vivo usage. However, nucleases are ubiquitous, and as we have yet to characterize the entire human microbiome it is likely that many nucleases are yet to be identified. Any novel, unusual enzymes present in vivo might reduce the efficacy of RNA-based therapeutics, even when they are chemically modified. We have previously identified an RNA-based aptamer capable of neutralizing a broad spectrum of clinical HIV-1 isolates and are developing it as a vaginal and rectal microbicide candidate. As a first step we addressed aptamer stability in the milieu of proteins present in these environments. Here we uncover a number of different nucleases that are able to rapidly degrade 2'-F-modified RNA. We demonstrate that the aptamer can be protected from the nuclease(s) present in the vaginal setting, without affecting its antiviral activity, by replacement of key positions with 2'-O-Me-modified nucleotides. Finally, we show that the aptamer can be protected from all nucleases present in both vaginal and rectal compartments using Zn²⁺ cations. In conclusion we have derived a stable, antiviral RNA-based aptamer that could form the basis of a pre-exposure microbicide or be a valuable addition to the current tenofovir-based microbicide candidate undergoing clinical trials.
Background: Use of lubricant products is extremely common during receptive anal intercourse (RAI) yet has not been assessed as a risk for acquisition of sexually transmitted infections (STIs). ...Methods: Between 2006 and 2008, a rectal health and behavior study was conducted in Baltimore and Los Angeles as part of the University of California, Los Angeles Microbicide Development Program (NIAID IPCP# #0606414). Participants completed questionnaires, and rectal swabs were tested for Neisseria gonorrhoeae and Chlamydia trachomatis with the Aptima Combo 2 assay, and blood was tested for syphilis (for RPR and TPHA with titer) and HIV. Of those reporting lubricant use and RAI, STI results were available for 380 participants. Univariate and multivariate regressions assessed associations of lubricant use in the past month during RAI with prevalent STIs. Results: Consistent lubricant use during RAI in the past month was reported by 36% (137/380) of participants. Consistent past month lubricant users had a higher prevalence of STI than inconsistent users (9.5% vs. 2.9%; P = 0.006). In a multivariable logistic regression model, testing positive for STI was associated with consistent use of lubricant during RAI in the past month (adjusted odds ratio: 2.98 95% confidence interval: 1.09, 8.15) after controlling for age, gender, study location, HIV status, and numbers of RAI partners in the past month. Conclusions: Findings suggest some lubricant products may increase vulnerability to STIs. Because of wide use of lubricants and their potential as carrier vehicles for microbicides, further research is essential to clarify if lubricant use poses a public health risk.
The association between oral human papillomavirus 16 (HPV16) DNA load and infection clearance was evaluated among 88 individuals with oral HPVI6 infection who were identified within a prospective ...cohort of 1470 HIV-infected and uninfected individuals. Oral rinse specimens were collected semiannually for up to 5 years. The oral HPV16 load at the time of the first positive test result was significantly associated with the time to clearance of infection (continuous P trends <.01). Notably, clearance rates by 24 months were 41% and 94% in the highest and lowest HPV16 load tertiles (P = .03), respectively. High oral HPV16 load warrants consideration as a biomarker for infection persistence, the presumed precursor of HPV16-associated oropharyngeal cancer.
We examined product adherence among 187 men who have sex with men and transgender women enrolled in a phase II, crossover trial comparing safety and acceptability of an oral tablet and a rectal gel ...used daily for HIV prevention. Participants reported adherence via daily text messages during 8-week periods. Trajectory analysis identified weekly patterns. Polytomous logistic regression identified characteristics associated with higher probability of trajectory group membership. We identified 3 groups per product: high-adherers (72% daily oral, 70% daily gel); decreasing-adherers (20% daily oral, 22% daily gel); and low-adherers (8% daily oral, 9% daily gel). Daily oral high-adherers (compared with low-adherers) were more likely to self-identify as male (OR = 4.76, 95% CI:1.35-16.67), to have more sexual partners (OR = 1.67, 95% CI:1.04-2.63), and to find the tablet easy to swallow (OR = 2.22, 95% CI:1.08-4.76). Daily gel high-adherers (compared with low-adherers) were more likely to be older (OR = 1.16, 95% CI:1.05-1.28), to find gel application easier at the last few applications (OR = 2.27, 95% CI:1.01-5.00), and to report a change in routine if gel was not used (OR = 5.26, 95% CI:1.23-100.00). Characteristics of participants likely to be high-adherers to product use vary according to product. Evaluation of acceptability prior to phase II/III trials could identify participants likely to maintain high adherence.
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Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, OILJ, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK, VSZLJ
Rectal use of a 1% tenofovir (TFV) gel is currently being evaluated for HIV prevention. While careful assessment of mucosal safety of candidate microbicides is a primary concern, tools to assess ...mucosal toxicity are limited. Mass spectrometry-based proteomics is a sensitive and high-throughput technique that can provide in-depth information on inflammation processes in biological systems. In this study, we utilized a proteomics approach to characterize mucosal responses in study participants involved in a phase 1 clinical trial of a rectal TFV-based gel. Project Gel was a phase 1 randomized (1:1), double-blind, multisite, placebo-controlled trial in which 24 participants received rectal TFV or a universal placebo hydroxyethyl cellulose (HEC) over a course of 8 daily doses. Rectal mucosal swabs were collected after 0, 1, and 8 doses and were analyzed by label-free tandem mass spectrometry. Differential protein expression was evaluated using a combination of paired (time-effects) and unpaired (across study arm) t-tests, and multivariate least absolute shrinkage and selection operator (LASSO) modeling. Within the TFV arm, 7% (17/249, p < .05) and 10% (25/249, p < .05) of total proteins changed after 1 and 8 daily applications of TFV gel, respectively, compared to 3% (7/249, p < .05) and 6% (16/249, p < .05) in the HEC arm. Biofunctional analysis associated TFV use with a decrease in epidermal barrier proteins (adj. p = 1.21 × 10
). Multivariate modeling identified 13 proteins that confidently separated TFV gel users (100% calibration and 96% cross-validation accuracy), including the epithelial integrity factors (FLMNB, CRNN, CALM), serpins (SPB13, SPB5), and cytoskeletal proteins (VILI, VIME, WRD1). This study suggested that daily rectal applications of a 1% TFV gel may be associated with mucosal proteome changes involving epidermal development. Further assessment of more extended use of TFV-gel is recommended to validate these initial associations.
BACKGROUNDThe quadrivalent human papillomavirus (qHPV) and 9 valent (nHPV) vaccine are licensed for males to prevent anal HPV–associated dysplasia and cancer caused by HPV types 6, 11, 16, and 18 ...(qHPV) and additional types 33, 35, 45, 52, and 58 (nHPV), respectively. Both conditions are common in HIV-infected and HIV-uninfected men who have sex with men (MSM). It is not well documented which anal HPV vaccine types are most prevalent in Southeast Asia.
METHODSA convenience sample of 400 anal swabs were obtained from 200 HIV-infected and 200 HIV-uninfected sexually active Bangkok MSM Cohort Study participants. After swab collection in PreservCyt (Cytyc Corp, Marlborough, MA), the media was stored at −80°C until processing. DNA was extracted, amplified by polymerase chain reaction, denatured, and then hybridized to probes for 37 HPV types and β-globin.
RESULTSThe mean participant age was 25.6 years (range, 18–55 years); the mean CD4 T-cell count was 410 cells/mm in the HIV-infected participants. Among all swab samples, 386 (192 HIV-positive and 194 HIV-negative) had adequate β-globin for HPV genotype testing. Anal HPV type was detected in 44.3% of participants whose samples underwent genotype testing. Both qHPV and nHPV types were more frequently detected in HIV-infected compared with HIV-uninfected (42.2% vs. 23.2% P < 0.01, 50.0% vs. 24.2% P < 0.01), respectively). There were no significant relationships between social behaviors (alcohol use, drug use) or sexual behaviors (number of partners, condom usage, sexual positioning) and anal HPV prevalence.
CONCLUSIONSThe prevalence of anal vaccine HPV types in Thai MSM was similar to that reported in MSM from Western populations and has a similar distribution by HIV status. Targeting young MSM with vaccination could offer protection against HPV vaccine types.
BACKGROUND:For women, the order of penile insertion, condom use, and ejaculation by orifice during sexual events affects the probability of HIV transmission and design of HIV prevention methods.
...METHODS:From October 2006 to June 2009, 431 women in Los Angeles and Baltimore in a rectal health study reported the sequence of penile insertion, condom use, and ejaculation by orifice location by computer-assisted self-interview. Multinomial logistic regression identified predictors of condom use by orifice among women who reported vaginal intercourse (VI) during their last anal intercourse (AI) event.
RESULTS:Of the 192 reporting on a last AI event, 96.3% (180/187) reported VI. Of these, 83.1% had VI before AI. Including the 36% who ejaculated in both the rectum and vagina, 66% report any ejaculation in the vagina and 45% in the rectum. One-third used a condom for both VI and AI, <10% for VI only or AI only, and half used no condoms. After adjusting for race, partner type, and substance use, compared with women who used condoms for both VI and AI at last AI, being older (units = 5 years) adjusted odds ratio (AOR) = 0.76; 95% confidence interval (CI)0.60 to 0.96, with serodiscordant partners (AOR = 0.22; 95% CI0.08 to 0.61), and HIV-positive with seroconcordant partners (AOR = 0.15; 95% CI0.04 to 0.54) were associated with not using condoms.
CONCLUSIONS:For most of the women in our study VI accompanied AI, with AI usually occurring after VI. This evidence for use of multiple orifices during the same sexual encounter and low use of condoms across orifices supports the need for a multicompartment HIV prevention strategy.
The ex vivo mucosal explant model is frequently used to test the efficacy of microbicides that have the potential for preventing HIV-1 transmission. The conventional assessment of product efficacy ...has been the extent of HIV-1 p24 suppression in supernatant fluids sampled up to day 14 after HIV-1 challenge ex vivo. The purpose of this study was to determine if measurement of HIV-1 nucleic acids by real-time PCR and HIV-1 integration by Alu-gag PCR provides advantages with regard to monitoring HIV-1 infection in explants. Rectal biopsies from HIV-1-negative individuals were challenged with 1 × 10(5) virions/ml of HIV-1BaL or HIV-1CH077 ex vivo. HIV-1 RNA and HIV-1 p24 in supernatant fluids and HIV-1 nucleic acids and integrated provirus in individual biopsies were measured at days 1-14 after infection. HIV-1 RNA and proviral DNA were measured by quantitative real-time PCR (qRT-PCR) while integrated virus was detected by Alu-gag PCR. Real-time PCR assays detecting HIV-1 DNA and RNA performed similarly provided that the infecting virus sequences were a good match with the sequences of the assay primers and probes. Increased HIV-1 nucleic acid levels and DNA integration were measurable on days 11 and 14 after infection. The magnitude of explant infection was similar after challenge with HIV-1BaL and HIV-1CH077, although the trajectory of infection was delayed in the HIV-1CH077-infected biopsies. In the majority of experiments, qRT-PCR did not appreciably shorten the time necessary to detect evidence of HIV-1 infection.
During Phase 1 pharmacokinetic/pharmacodynamics studies, participants may undergo multiple sigmoidoscopies, with a collection of 10-20 biopsies during each procedure. This article characterizes the ...safety of flexible sigmoidoscopies in clinical trial participants. We determined the number of flexible sigmoidoscopies and rectal biopsies that participants underwent and analyzed the frequency, duration, and severity of flexible sigmoidoscopy-related adverse events (AEs). During the study period, 278 participants underwent 1,004 flexible sigmoidoscopies with the collection of 15,930 rectal biopsies. The average number of procedures per participant was 3.6 (median 3; range 1-25), with an average time interval between procedures of 61.8 days (median 28 days; range 1-1,159). There were no serious AEs. Sixteen AEs were related to flexible sigmoidoscopy and occurred in 16 participants, leading to an overall 1.6% (16/1,004) AE rate per procedure and 0.1% (16/15,930) AE rate per biopsy. Of the 16 AEs, 8 (50%) involved abdominal pain, diarrhea, bleeding, flatulence, and bloating, with an average duration of 4.7 days (median 1 day; range 1-28). Most (14/16) AEs were categorized as Grade 1 (mild), whereas two of the AEs were Grade 2 (moderate). No participant withdrew due to procedure-related AEs. Overall, the number of AEs caused by flexible sigmoidoscopy with multiple biopsies was low and the severity was mild, suggesting that this procedure can be safely integrated into protocols requiring repeated intestinal mucosal sampling.
This study examined how acceptability of placebo gel with receptive anal intercourse (RAI) and likelihood of future rectal microbicide use varied across partner types. Because no rectal microbicide ...is available yet, use of placebo permitted the study of gel use behavior in real-life circumstances. A total of 87 men who have sex with men (MSM) aged 18 to 30 years inserted placebo gel rectally before RAI during 12 weeks. Using mixed-methods design, participants completed a behavioral questionnaire and in-depth interview. In all, 62 men (71.3%) reported gel use with a lover (i.e., spouse equivalent, boyfriend), 32 (36.8%) with a one-night stand (i.e., man with whom you had sex once), and 29 (33.3%) with an "other" male partner. While gel acceptability was high across partner types, use with lovers was facilitated by trust and familiarity; yet trust made participants believe protection was less necessary. Conversely, participants expressed high likelihood of using gel with one-night stands, whom they perceived as riskier; yet they felt less comfortable discussing gel with them, often resorting to covert use or forgoing gel. A successful microbicide will be positioned as a sexual pleasure enhancer so that men can present it to their lovers and other partners as a gel that improves sex and secondarily prevents human immunodeficiency virus (HIV).
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