A Phase 1 Clinical Trial to Assess the Safety and Pharmacokinetics of a Tenofovir Alafenamide/Elvitegravir Insert Administered Rectally for HIV Prevention.

BACKGROUND: On-demand topical products could be an important tool for human immunodeficiency virus (HIV) prevention. We evaluated the safety, pharmacokinetics, and ex vivo pharmacodynamics of a tenofovir alafenamide/elvitegravir (TAF/EVG, 20 mg/16 mg) insert administered rectally. METHODS: MTN-039 was a phase 1, open-label, single-arm, 2-dose study. Blood, rectal fluid, and rectal tissue were collected over 72 hours following rectal administration of 1 and 2 TAF/EVG inserts for each participant. RESULTS: TAF/EVG inserts were safe and well tolerated. EVG and tenofovir (TFV) were detected in blood plasma at low concentrations: median peak concentrations after 2 inserts were EVG 2.4 ng/mL and TFV 4.4 ng/mL. Rectal tissue EVG peaked at 2 hours (median, 2 inserts = 9 ng/mg) but declined to below limit of quantification in the majority of samples at 24 hours, whereas tenofovir diphosphate (TFV-DP) remained high >2000 fmol/million cells for 72 hours with 2 inserts. Compared to baseline, median cumulative log10 HIV p24 antigen of ex vivo rectal tissue HIV infection was reduced at each time point for both 1 and 2 inserts (P < .065 and P < .039, respectively). DISCUSSION: Rectal administration of TAF/EVG inserts achieved high rectal tissue concentrations of EVG and TFV-DP with low systemic drug exposure and demonstrable ex vivo inhibition of HIV infection for 72 hours. Clinical Trials Registration . NCT04047420.

Tenofovir Douche as HIV Preexposure Prophylaxis for Receptive Anal Intercourse: Safety, Acceptability, Pharmacokinetics, and Pharmacodynamics (DREAM 01).

BACKGROUND: Despite highly effective HIV preexposure prophylaxis (PrEP) options, no options provide on-demand, nonsystemic, behaviorally congruent PrEP that many desire. A tenofovir-medicated rectal douche before receptive anal intercourse may provide this option. METHODS: Three tenofovir rectal douches-220 mg iso-osmolar product A, 660 mg iso-osmolar product B, and 660 mg hypo-osmolar product C-were studied in 21 HIV-negative men who have sex with men. We sampled blood and colorectal tissue to assess safety, acceptability, pharmacokinetics, and pharmacodynamics. RESULTS: The douches had high acceptability without toxicity. Median plasma tenofovir peak concentrations for all products were several-fold below trough concentrations associated with oral tenofovir disoproxil fumarate (TDF). Median colon tissue mucosal mononuclear cell (MMC) tenofovir-diphosphate concentrations exceeded target concentrations from 1 hour through 3 to 7 days after dosing. For 6-7 days after a single product C dose, MMC tenofovir-diphosphate exceeded concentrations expected with steady-state oral TDF 300 mg on-demand 2-1-1 dosing. Compared to predrug baseline, HIV replication after ex vivo colon tissue HIV challenge demonstrated a concentration-response relationship with 1.9 log10 maximal effect. CONCLUSIONS: All 3 tenofovir douches achieved tissue tenofovir-diphosphate concentrations and colorectal antiviral effect exceeding oral TDF and with lower systemic tenofovir. Tenofovir douches may provide a single-dose, on-demand, behaviorally congruent PrEP option, and warrant continued development. Clinical Trials Registration . NCT02750540.

Tenofovir, emtricitabine, lamivudine and dolutegravir concentrations in plasma and urine following drug intake cessation in a randomized controlled directly observed pharmacokinetic trial to aid point-of-care testing.

BACKGROUND: Poor adherence to ART and pre-exposure prophylaxis (PrEP) can impact patient and public health. Point-of-care testing (POCT) may aid monitoring and adherence interventions. OBJECTIVES: We report the pharmacokinetics of tenofovir [dosed as tenofovir disoproxil (TDF) and tenofovir alafenamide (TAF)], emtricitabine (FTC), lamivudine (3TC) and dolutegravir (DTG) in plasma and urine following drug cessation to evaluate adherence targets in urine for POCT. METHODS: Subjects were randomized (1:1) to receive DTG/FTC/TAF or DTG/3TC/TDF for 15 days. Plasma and spot urine were collected on Day 15 (0-336 h post final dose). Drug concentrations were quantified using LC-MS, and non-linear mixed-effects models applied to determine drug disposition between matrices and relationship with relevant plasma [dolutegravir protein-adjusted 90% inhibitory concentration (PA-IC90 = 64 ng/mL) and minimum effective concentration (MEC = 324 ng/mL)] and urinary thresholds [tenofovir disoproxil fumarate 1500 ng/mL]. RESULTS: Of 30 individuals enrolled, 29 were included (72% female at birth, 90% Caucasian). Median (range) predicted time to plasma dolutegravir PA-IC90 and MEC were 83.5 (41.0-152) and 49.0 h (23.7-78.9), corresponding to geometric mean (90%) urine concentrations of 5.42 (4.37-6.46) and 27.4 ng/mL (22.1-32.7). Tenofovir in urine reached 1500 ng/mL by 101 h (58.6-205) with an equivalent plasma concentration of 6.20 ng/mL (4.21-8.18). CONCLUSIONS: These data support use of a urinary tenofovir threshold of <1500 ng/mL (tenofovir disoproxil fumarate-based regimens) as a marker of three or more missed doses for a POCT platform. However, due to low dolutegravir concentrations in urine, POCT would be limited to a readout of recent dolutegravir intake (one missed dose).

MTN-033: a Phase 1 Study Comparing Applicator versus "as Lubricant" Delivery of Rectal Dapivirine Gel.

Data to inform behaviorally congruent delivery of rectal microbicides as lubricants are scant. Dapivirine (DPV) is a nonnucleoside reverse transcriptase inhibitor which has been demonstrated to be well-tolerated and efficacious in multiple clinical trials when used in a vaginal ring formulation. DPV gel administered rectally with an applicator was found to be well-tolerated in a phase 1 clinical trial. MTN-033, a single site, open label, sequence randomized, crossover study, enrolled HIV-negative men to receive 0.05% DPV gel intrarectally using an applicator (2.5 g) and self-administered on an artificial phallus as lubricant (up to 10 g). The study evaluated the pharmacokinetics (in plasma, rectal fluid, and mucosal rectal tissue), safety, acceptability, and pharmacodynamics of DPV gel when applied rectally. Statistical comparisons between methods of application were performed using mixed effects models or Wilcoxon's signed rank tests. Sixteen participants used DPV gel by applicator and 15/16 participants used gel as lubricant (mean, 1.8 g; SD, 0.8). DPV plasma AUC0-24h after use as lubricant was estimated to be 0.41 times the AUC0-24h (95% CI 0.24, 0.88) after use with applicator. While DPV was quantifiable in plasma and luminal fluid, it was not quantifiable in tissue for both applicator and as lubricant administration. No related adverse events (AE) were reported, and 15/15 participants felt the gel was easy to use. Evidence of local delivery and systemic absorption of DPV when dosed as an anal lubricant supports the feasibility and potential for development of lubricant-delivered rectal microbicides. There were no safety concerns associated with use of DPV gel and participants reported finding it easy to use. However, lower DPV exposure in plasma and lack of quantifiable DPV in rectal tissue indicate that higher potency, concentration, and longer half-life antiretrovirals with optimized formulations will be needed to achieve protective tissue concentrations.

Tofacitinib inhibits inflammatory cytokines from ulcerative colitis and healthy mucosal explants and is associated with pSTAT1/3 reduction in T-cells.

Poor translatability of animal disease models has hampered the development of new inflammatory bowel disorder (IBD) therapeutics. We describe a preclinical, ex vivo system using freshly obtained and well-characterized human colorectal tissue from patients with ulcerative colitis (UC) and healthy control (HC) participants to test potential therapeutics for efficacy and target engagement, using the JAK/STAT inhibitor tofacitinib (TOFA) as a model therapeutic. Colorectal biopsies from HC participants and patients with UC were cultured and stimulated with multiple mitogens ± TOFA. Soluble biomarkers were detected using a 29-analyte multiplex ELISA. Target engagement in CD3+CD4+ and CD3+CD8+ T-cells was determined by flow cytometry in peripheral blood mononuclear cells (PBMCs) and isolated mucosal mononuclear cells (MMCs) following the activation of STAT1/3 phosphorylation. Data were analyzed using linear mixed-effects modeling, t test, and analysis of variance. Biomarker selection was performed using penalized and Bayesian logistic regression modeling, with results visualized using uniform manifold approximation and projection. Under baseline conditions, 27 of 29 biomarkers from patients with UC were increased versus HC participants. Explant stimulation increased biomarker release magnitude, expanding the dynamic range for efficacy and target engagement studies. Logistic regression analyses identified the most representative UC baseline and stimulated biomarkers. TOFA inhibited biomarkers dependent on JAK/STAT signaling. STAT1/3 phosphorylation in T-cells revealed compartmental differences between PBMCs and MMCs. Immunogen stimulation increases biomarker release in similar patterns for HC participants and patients with UC, while enhancing the dynamic range for pharmacological effects. This work demonstrates the power of ex vivo human colorectal tissue as preclinical tools for evaluating target engagement and downstream effects of new IBD therapeutic agents.NEW & NOTEWORTHY Using colorectal biopsy material from healthy volunteers and patients with clinically defined IBD supports translational research by informing the evaluation of therapeutic efficacy and target engagement for the development of new therapeutic entities. Combining experimental readouts from intact and dissociated tissue enhances our understanding of the tissue-resident immune system that contribute to disease pathology. Bayesian logistic regression modeling is an effective tool for predicting ex vivo explant biomarker release patterns.

A Pilot Study of the Immunologic, Virologic, and Pathologic Consequences of Intra-anal 5% Imiquimod in HIV-1-Infected Men With High-Grade Squamous Intraepithelial Lesions.

BACKGROUND: Imiquimod can be used to treat internal anal high-grade squamous intraepithelial lesions. In HIV-1-infected individuals there is a theoretical concern for increased HIV replication in anorectal tissue secondary to imiquimod-induced mucosal inflammation. OBJECTIVE: The purpose of this study was to assess local virologic, immunologic, and pathologic effects of imiquimod treatment in HIV-infected individuals. DESIGN: This was a pilot study at a single academic center. SETTINGS: The study was conducted at the University of Pittsburgh Anal Dysplasia Clinic. PATIENTS: HIV-1-infected individuals with biopsy-confirmed internal anal high-grade squamous intraepithelial lesions were included. INTERVENTION: Imiquimod cream was prescribed for intra-anal use 3 times per week for 9 weeks. MAIN OUTCOME MEASURES: Anal human papillomavirus typing, anal and rectal tissue HIV-1 RNA and DNA quantification, cytokine gene expression, and anal histology were measured. RESULTS: Nine evaluable participants (1 participant was lost to follow-up) were all white men with a median age of 46 years (interquartile range = 12 y) and a median CD4 T-cell count of 480 cells per cubic millimeter (interquartile range = 835). All were taking antiretroviral therapy, and 7 of 9 had HIV-1 RNA <50 copies per milliliter. The median dose of imiquimod used was 27.0 (interquartile range = 3.5), and there was a median of 11 days (interquartile range = 10 d) from last dose to assessment. There was no progression to cancer, no significant change in the number of human papillomavirus types detected, and no significant change in quantifiable cytokines/HIV-1 RNA or DNA levels in anal or rectal tissue. Seven (35%) of 20 high-grade lesions resolved to low-grade squamous intraepithelial lesions. LIMITATIONS: The study was limited by the small number of participants and variable time to final assessment. CONCLUSIONS: Intra-anal imiquimod showed no evidence of immune activation or increase in HIV-1 viral replication in anal and rectal tissue and confirmed efficacy for intra-anal high-grade squamous intraepithelial lesion treatment morbidity. See Video Abstract at http://links.lww.com/DCR/A498.

Ex-vivo rectal tissue infection with HIV-1 to assess time to protection following oral preexposure prophylaxis with tenofovir disoproxil/emtricitabine.

OBJECTIVES: We wished to assess time to protection from HIV-1 infection following oral tenofovir disoproxil and emtricitabine (TDF/FTC) as preexposure prophylaxis (PrEP), using ex-vivo rectal tissue infections and drug concentration measures in blood and rectal tissue. DESIGN/METHODS: Participants from the ANRS PREVENIR study (NCT03113123) were offered this sub-study after a 14-day wash-out. We used an ex-vivo model to evaluate rectal tissue HIV-1 susceptibility before and after PrEP, 2 h after two pills or 7 days of a daily pill of TDF/FTC. PrEP efficacy was expressed by the difference (after-before) of 14-day cumulative p24 antigen levels. TFV-DP and FTC-TP levels were measured in rectal tissue and PBMCs and correlated with HIV-1 infection. RESULTS: Twelve and 11 men were analyzed in the 2 h-double dose and 7 days-single dose groups, respectively. Cumulative p24 differences after-before PrEP were -144 pg/ml/mg (IQR[-259;-108]) for the 2 h-double dose group ( P  = 0.0005) and -179 pg/ml/mg (IQR [-253;-86]) for the 7 days-single dose group ( P  = 0.001), with no differences between groups ( P  = 0.93). Rectal TFV-DP was below quantification after a double dose, but FTC-TP levels were similar to levels at 7 days. There was a significant correlation between rectal FTC-TP levels and p24 changes after a double dose ( R  = -0.84; P  = 0.0001). CONCLUSION: Oral TDF/FTC provided similar protection against HIV-1 infection of rectal tissue 2 h after a double dose or 7 days of a daily dose. At 2 h, this protection seems driven by high FTC-TP concentrations in rectal tissue. This confirms the importance of combining TDF and FTC to achieve early protection.

UNSEG: unsupervised segmentation of cells and their nuclei in complex tissue samples.

Multiplexed imaging technologies have made it possible to interrogate complex tissue microenvironments at sub-cellular resolution within their native spatial context. However, proper quantification of this complexity requires the ability to easily and accurately segment cells into their sub-cellular compartments. Within the supervised learning paradigm, deep learning-based segmentation methods demonstrating human level performance have emerged. However, limited work has been done in developing such generalist methods within the unsupervised context. Here we present an easy-to-use unsupervised segmentation (UNSEG) method that achieves deep learning level performance without requiring any training data via leveraging a Bayesian-like framework, and nucleus and cell membrane markers. We show that UNSEG is internally consistent and better at generalizing to the complexity of tissue morphology than current deep learning methods, allowing it to unambiguously identify the cytoplasmic compartment of a cell, and localize molecules to their correct sub-cellular compartment. We also introduce a perturbed watershed algorithm for stably and automatically segmenting a cluster of cell nuclei into individual nuclei that increases the accuracy of classical watershed. Finally, we demonstrate the efficacy of UNSEG on a high-quality annotated gastrointestinal tissue dataset we have generated, on publicly available datasets, and in a range of practical scenarios.

Pharmacokinetic Modeling to Guide Preclinical Development of an Islatravir-Eluting Reservoir-Style Biodegradable Implant for Long-Acting HIV PrEP.

Long-acting injectable cabotegravir is more effective than daily oral PrEP at preventing HIV transmission due to improved adherence, but requires bi-monthly large-volume intramuscular injections. Subcutaneous (SC) contraceptive implants can be formulated with antiretrovirals for extended-duration HIV PrEP. Islatravir (ISL) is a first-in-class, investigational antiretroviral with pharmacologic properties well-suited for implant delivery. We performed preclinical studies for the development of a reservoir-style, poly(ε-caprolactone) ISL-eluting implant by conducting a single-dose SC ISL dose-ranging pharmacokinetic (PK) study of 0.1, 0.3, and 1 mg/kg in adult Wistar rats. Non-compartmental analysis was conducted, and dose proportionality assessed for ISL plasma and intracellular islatravir-triphosphate (ISL-tp). Population PK models estimated ISL's unit impulse response to deconvolve ISL-implant in vivo absorption rate (mg/day) and cumulative mass (mg) from published rat plasma PK (n = 10). Drug release was interpreted using four kinetic models. Dose proportionality was affirmed for ISL and ISL-tp. A first-order, two-compartment model fitted the SC ISL bolus data. Mean (SD) absorption rate from 0 to 154 days was 0.072 ± 0.024 mg/day, and cumulative mass at 154 days was 8.67 ± 3.22 mg. ISL absorption was well-described by zero-order (r2 = 0.95) and Ritger-Peppas (r2 = 0.98). Our zero-order ISL-release poly(ε-caprolactone) implant is projected to achieve clinical PK above ISL-tp's PrEP efficacy threshold. Continued development for HIV PrEP applications is warranted.

Mirroring UC care pathways in refractory immune checkpoint inhibitor (ICI)-mediated colitis: distinct features and common pathways.

Immune checkpoint inhibitors (ICI) have transformed the management of cancer, producing durable responses in a subset of treated patients across multiple malignancies. Immune-mediated diarrhea and colitis (imDC) occurs in up to 20% of ICI-treated patients. The risk of ICI imDC is dependent upon the agent and is commoner with anti-CTLA-4 compared to anti-PD-1 ICIs. Generally, imDC is treated with steroids and agents targeting TNFα or α4ß7 integrin. However, the management of steroids and/or biologic refractory imDC is unclear. We present a case of imDC in a 68-year-old female who failed to respond clinically, biochemically and immunohistochemically to corticosteroids, infliximab and vedolizumab. A trial of tofacitinib, a pan-JAK inhibitor, led to rapid clinical, biochemical and immunohistochemical control of imDC. ICIs result in a striking accumulation of cytotoxic and proliferative CD8 + T cells within tumor. However, the cellular and molecular mechanisms underlying imDC remain unclear. Herein, we observed significant T cell enrichment; and the successful treatment with tofacitinib highlights the potential of multiple convergent inflammatory pathways in imDC and inflammatory colitis.

rxCOV is a quantitative metric for assessing immunoassay analyte fidelity.

Immunoassay based bioanalytical measurements are widely used in a variety of biomedical research and clinical settings. In these settings they are assumed to faithfully represent the experimental conditions being tested and the sample groups being compared. Although significant technical advances have been made in improving sensitivity and quality of the measurements, currently no metrics exist that objectively quantify the fidelity of the measured analytes with respect to noise associated with the specific assay. Here we introduce ratio of cross-coefficient-of-variation (rxCOV), a fidelity metric for objectively assessing immunoassay analyte measurement quality when comparing its differential expression between different sample groups or experimental conditions. We derive the metric from first principles and establish its feasibility and applicability using simulated and experimental data. We show that rxCOV assesses fidelity independent of statistical significance, and importantly, identifies when latter is meaningful. We also discuss its importance in the context of averaging experimental replicates for increasing signal to noise ratio. Finally, we demonstrate its application in a Lynch Syndrome case study. We conclude by discussing its applicability to multiplexed immunoassays, other biosensing assays, and to paired and unpaired data. We anticipate rxCOV to be adopted as a simple and easy-to-use fidelity metric for performing robust and reproducible biomedical research.

Immune Microenvironment Profiling of Normal Appearing Colorectal Mucosa Biopsied Over Repeat Patient Visits Reproduciably Separates Lynch Syndrome Patients Based on Their History of Colon Cancer.

Introduction: Lynch syndrome (LS) is the most common hereditary cause of colorectal cancer (CRC), increasing lifetime risk of CRC by up to 70%. Despite this higher lifetime risk, disease penetrance in LS patients is highly variable and most LS patients undergoing CRC surveillance will not develop CRC. Therefore, biomarkers that can correctly and consistently predict CRC risk in LS patients are needed to both optimize LS patient surveillance and help identify better prevention strategies that reduce risk of CRC development in the subset of high-risk LS patients. Methods: Normal-appearing colorectal tissue biopsies were obtained during repeat surveillance colonoscopies of LS patients with and without a history of CRC, healthy controls (HC), and patients with a history of sporadic CRC. Biopsies were cultured in an ex-vivo explant system and their supernatants were assayed via multiplexed ELISA to profile the local immune signaling microenvironment. High quality cytokine signatures were identified using rx COV fidelity metric. These signatures were used to perform biomarker selection by computing their selection probability based on penalized logistic regression. Results: Our study demonstrated that cytokine based local immune microenvironment profiling was reproducible over repeat visits and sensitive to patient LS-status and CRC history. Furthermore, we identified sets of biomarkers whose differential expression was predictive of LS-status in patients when compared to sporadic CRC patients and in identifying those LS patients with or without a history of CRC. Enrichment analysis based on these biomarkers revealed an LS and CRC status dependent constitutive inflammatory state of the normal appearing colonic mucosa. Discussion: This prospective pilot study demonstrated that immune profiling of normal appearing colonic mucosa discriminates LS patients with a prior history of CRC from those without it, as well as patients with a history of sporadic CRC from HC. Importantly, it suggests existence of immune signatures specific to LS-status and CRC history. We anticipate that our findings have the potential to assess CRC risk in individuals with LS and help in preemptively mitigating it by optimizing surveillance and identifying candidate prevention targets. Further studies are required to validate our findings in an independent cohort of LS patients over multiple visits.

Immune microenvironment profiling of normal appearing colorectal mucosa biopsied over repeat patient visits reproducibly separates lynch syndrome patients based on their history of colon cancer.

Introduction: Lynch syndrome (LS) is the most common hereditary cause of colorectal cancer (CRC), increasing lifetime risk of CRC by up to 70%. Despite this higher lifetime risk, disease penetrance in LS patients is highly variable and most LS patients undergoing CRC surveillance will not develop CRC. Therefore, biomarkers that can correctly and consistently predict CRC risk in LS patients are needed to both optimize LS patient surveillance and help identify better prevention strategies that reduce risk of CRC development in the subset of high-risk LS patients. Methods: Normal-appearing colorectal tissue biopsies were obtained during repeat surveillance colonoscopies of LS patients with and without a history of CRC, healthy controls (HC), and patients with a history of sporadic CRC. Biopsies were cultured in an ex-vivo explant system and their supernatants were assayed via multiplexed ELISA to profile the local immune signaling microenvironment. High quality cytokines were identified using the rxCOV fidelity metric. These cytokines were used to perform elastic-net penalized logistic regression-based biomarker selection by computing a new measure - overall selection probability - that quantifies the ability of each marker to discriminate between patient cohorts being compared. Results: Our study demonstrated that cytokine based local immune microenvironment profiling was reproducible over repeat visits and sensitive to patient LS-status and CRC history. Furthermore, we identified sets of cytokines whose differential expression was predictive of LS-status in patients when compared to sporadic CRC patients and in identifying those LS patients with or without a history of CRC. Enrichment analysis based on these biomarkers revealed an LS and CRC status dependent constitutive inflammatory state of the normal appearing colonic mucosa. Discussion: This prospective pilot study demonstrated that immune profiling of normal appearing colonic mucosa discriminates LS patients with a prior history of CRC from those without it, as well as patients with a history of sporadic CRC from HC. Importantly, it suggests the existence of immune signatures specific to LS-status and CRC history. We anticipate that our findings have the potential to assess CRC risk in individuals with LS and help in preemptively mitigating it by optimizing surveillance and identifying candidate prevention targets. Further studies are required to validate our findings in an independent cohort of LS patients over multiple visits.

A topical rectal douche product containing Q-Griffithsin does not disrupt the epithelial border or alter CD4+ cell distribution in the human rectal mucosa.

To reduce HIV transmission, locally applied pre-exposure prophylaxis (PrEP) products for anorectal use will be important complements to oral and injectable PrEP products already available. It is critical to preserve an intact rectal epithelium and avoid an influx of mucosal HIV target cells with such product use. In this phase 1 clinical trial, we evaluated application of a topical rectal douche product containing Q-Griffithsin (Q-GRFT). Colorectal tissue samples were obtained via sigmoidoscopy at baseline, 1 and 24 h after single-dose exposure in 15 healthy volunteers. In situ staining for epithelial junction markers and CD4+ cells were assessed as an exploratory endpoint. A high-throughput, digitalized in situ imaging analysis workflow was developed to visualize and quantify these HIV susceptibility markers. We observed no significant differences in epithelial distribution of E-cadherin, desmocollin-2, occludin, claudin-1, or zonula occludens-1 when comparing the three timepoints or Q-GRFT versus placebo. There were also no differences in %CD4+ cells within the epithelium or lamina propria in any of these comparisons. In conclusion, the rectal epithelium and CD4+ cell distribution remained unchanged following topical application of Q-GRFT. In situ visualization of HIV susceptibility markers at mucosal sites could be useful to complement standard product safety assessments.

UNSEG: unsupervised segmentation of cells and their nuclei in complex tissue samples.

Multiplexed imaging technologies have made it possible to interrogate complex tumor microenvironments at sub-cellular resolution within their native spatial context. However, proper quantification of this complexity requires the ability to easily and accurately segment cells into their sub-cellular compartments. Within the supervised learning paradigm, deep learning based segmentation methods demonstrating human level performance have emerged. Here we present an unsupervised segmentation (UNSEG) method that achieves deep learning level performance without requiring any training data. UNSEG leverages a Bayesian-like framework and the specificity of nucleus and cell membrane markers to construct an a posteriori probability estimate of each pixel belonging to the nucleus, cell membrane, or background. It uses this estimate to segment each cell into its nuclear and cell-membrane compartments. We show that UNSEG is more internally consistent and better at generalizing to the complexity of tissue samples than current deep learning methods. This allows UNSEG to unambiguously identify the cytoplasmic compartment of a cell, which we employ to demonstrate its use in an example biological scenario. Within the UNSEG framework, we also introduce a new perturbed watershed algorithm capable of stably and accurately segmenting a cell nuclei cluster into individual cell nuclei. Perturbed watershed can also be used as a standalone algorithm that researchers can incorporate within their supervised or unsupervised learning approaches to replace classical watershed. Finally, as part of developing UNSEG, we have generated a high-quality annotated gastrointestinal tissue dataset, which we anticipate will be useful for the broader research community. Segmentation, despite its long antecedents, remains a challenging problem, particularly in the context of tissue samples. UNSEG, an easy-to-use algorithm, provides an unsupervised approach to overcome this bottleneck, and as we discuss, can help improve deep learning based segmentation methods by providing a bridge between unsupervised and supervised learning paradigms.

Ultrastructural visualization of chromatin in cancer pathogenesis using a simple small-molecule fluorescent probe.

Imaging chromatin organization at the molecular-scale resolution remains an important endeavor in basic and translational research. Stochastic optical reconstruction microscopy (STORM) is a powerful superresolution imaging technique to visualize nanoscale molecular organization down to the resolution of ~20 to 30 nm. Despite the substantial progress in imaging chromatin organization in cells and model systems, its routine application on assessing pathological tissue remains limited. It is, in part, hampered by the lack of simple labels that consistently generates high-quality STORM images on the highly processed clinical tissue. We developed a fast, simple, and robust small-molecule fluorescent probe-cyanine 5-conjugated Hoechst-for routine superresolution imaging of nanoscale nuclear architecture on clinical tissue. We demonstrated the biological and clinical significance of imaging superresolved chromatin structure in cancer development and its potential clinical utility for cancer risk stratification.

An Open-Label Pharmacokinetic and Pharmacodynamic Assessment of Tenofovir Gel and Oral Emtricitabine/Tenofovir Disoproxil Fumarate.

The Microbicide Trials Network-017 study was undertaken to characterize the safety, acceptability, pharmacokinetic (PK), and pharmacodynamic profile of the reduced-glycerin (RG) 1% tenofovir (RG-TFV) gel compared to oral emtricitabine/tenofovir disoproxil fumarate (FTC/TDF). The study was a Phase 2, three-period, randomized sequence, open-label, expanded safety and acceptability crossover study. In each 8-week study period, HIV-1-uninfected participants were randomized to RG-TFV rectal gel daily or RG-TFV rectal gel before and after receptive anal intercourse (RAI) (or at least twice weekly in the event of no RAI), or daily oral FTC/TDF. A mucosal substudy was conducted at sites in the United States and Thailand. Samples were collected to evaluate PK and ex vivo biopsy challenge with HIV-1. A total of 195 men who have sex with men and transgender women were enrolled in the parent study and 37 in the mucosal substudy. As previously reported, both products were found to be safe and acceptable. Systemic TFV concentrations were significantly higher following oral exposure and daily rectal administration compared to RAI-associated product use (p < .001). All three routes of pre-exposure prophylaxis (PrEP) administration resulted in the inhibition of explant infection (p < .05), and there was a significant inverse correlation between explant HIV-1 p24 and tissue concentrations of TFV and FTC (p < .0001). Despite significant differences in systemic and mucosal drug concentrations, all three PrEP regimens were able to protect rectal explants from ex vivo HIV infection. These data suggest that there is a rationale for co-development of oral and topical antiretroviral PrEP for HIV prevention. Clinical Trial Registration number: NCT01687218.

A Randomized, Double Blind, Placebo-Controlled, Phase 1 Safety, and Pharmacokinetic Study of Dapivirine Gel (0.05%) Administered Rectally to HIV-1 Seronegative Adults (MTN-026).

Dapivirine (DPV), formulated as vaginal ring, demonstrated HIV risk reduction. MTN-026 explored DPV, formulated as rectal gel, for safety, pharmacokinetics (PK), and acceptability. HIV-uninfected men and women aged 18-45 years were enrolled at United States and Thailand sites and randomized 2:1 to receive DPV 0.05% or placebo gel via rectal applicator. A single-dose phase was followed by seven observed daily doses. Plasma and fluid and tissue from both rectum and cervix were collected at baseline and after the final dose over 72 h for PK, ex-vivo HIV-1 biopsy challenge, histology, and flow cytometry. Twenty-eight participants were randomized; 2 terminated early; 9 were female and 19 male; 12 were white, 11 Asian, 4 black, and 1 other race/ethnicity. Mean age was 28.5 and 34.2 years in the DPV and placebo arms, respectively. Thirty adverse events occurred (all Grade 1 or 2, except one unrelated Grade 3) without study arm differences. DPV rectal tissue concentrations [median (interquartile range)] 0.5-1 and 2 h after a single dose were 256 ng/g [below the lower limit of quantification (BLQ)-666] and BLQ (BLQ-600), respectively, then BLQ (BLQ-BLQ) from 24 to 72 h; concentrations following multiple doses were similar. The largest median DPV plasma concentrations were 0.33 ng/mL (0.15-0.48) after one dose and 0.40 (0.33-0.49) after seven doses. The DPV rectal gel was acceptable and without safety concerns. While DPV plasma concentrations were similar to the vaginal ring, rectal tissue concentrations were well below vaginal ring tissue concentrations, suggesting need for reformulation. Clinical trial number: NCT03239483.

A Randomized, Open-Label, Crossover Phase 1 Safety and Pharmacokinetic Study of Oral Maraviroc and Maraviroc 1% Gel (the CHARM-03 Study).

The Combination HIV Antiretroviral Rectal Microbicide-3 (CHARM-03) study was a randomized, open-label, crossover Phase 1 safety and pharmacokinetic (PK) study of oral maraviroc (MVC) and MVC 1% gel. At a single site, healthy HIV-uninfected men and women were enrolled and randomized to an open label crossover sequence of eight consecutive daily exposures to MVC 300 mg dosed orally, MCV 1% gel dosed rectally, and MVC 1% gel dosed vaginally. Male participants received oral and rectal dosing and female participants received oral, rectal, and vaginal dosing. Assessments were undertaken at baseline and following each 8-day period and included collection of plasma, rectal/cervical tissue (CT), and rectal/endocervical/vaginal fluids. Eleven men and nine women were enrolled. Two participants withdrew from the study before receiving study product. There were 25 adverse events, of which 24 were Grade 1 (G1) and one was G2 (unrelated). After eight doses, MVC was quantifiable in all samples following oral, rectal, or vaginal product administration. The highest drug concentrations in plasma, rectal tissue (RT), and CT were associated with oral, rectal, and vaginal drug delivery, respectively. There were significant reductions in tissue drug concentrations when rectal and cervical biopsies were incubated in media before tissue processing for PK (p < .0001). Only oral MVC was associated with limited protection in the rectal explant HIV challenge model (p < .05). There were no immunological changes in RT, and all products were acceptable to participants. In conclusion, all products were found to be safe and acceptable and did not induce local inflammation. The lack of ex vivo efficacy demonstrated in study samples may be due to rapid disassociation of MVC from the explant tissue. ClinicalTrials.gov Identifier: NCT02346084.

Ethanol consumption synergistically increases ultraviolet radiation induced skin damage and immune dysfunction.

BACKGROUND: Excessive UV radiation disrupts skin homeostasis by multiple mechanisms that extend beyond the simple erythema associated with sunburns including reduction of antioxidants, increased DNA damage, and impairment of skin immune responses. Recreational UV exposure frequently occurs concurrently with excessive ethanol (EtOH). Epidemiological studies suggest a harmful, dose-dependent impact of EtOH in the setting of high UV exposure, leading to increased severity of sunburns relative to those generated in the absence of EtOH. Furthermore, EtOH consumption and UV radiation have multiple overlapping effects on the skin that could account for the epidemiological association. OBJECTIVE: To elucidate the relationship between excessive EtOH ingestion and UV exposures on early skin damage and downstream immune dysfunction. METHODS: We examined the impact of UVB on local skin damage, including inflammation, sunburned cells, apoptotic cells, melanin and antioxidant levels, DNA damage and immune dysfunction in the presence or absence of EtOH ingestion by combining standard mouse models of EtOH consumption and UVB exposure models. To confirm that the observed changes in mouse skin were relevant to human skin, we investigated the effects of EtOH on UV-induced skin damage with human skin explants. RESULTS: We demonstrated that EtOH consumption and UV exposure act synergistically to increase the severity of local skin damage resulting in impaired melanin responses, reduced antioxidants, greater DNA damage, and immune dysfunction as measured by reduced contact hypersensitivity. CONCLUSIONS: The results support incorporation of the risks of combined UV exposure and excessive alcohol consumption into public health campaigns.