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Open Access Publications from the University of California

Recent Work

Since its founding in 1983 by California State Legislature, the California HIV/AIDS Research Program (CHRP) has supported excellent, timely, and innovative research that is attentive to the needs of California, accelerating progress towards prevention, care and treatment for HIV/AIDS. During this time over $250M has been awarded for over 2,000 research projects.

CHRP provides start-up funds for the development of cutting edge research in California, providing critical leverage to bring in federal and private dollars to the state. A 2006 survey of California investigators found that more than five dollars in federal and other grant support was generated for every dollar invested by CHRP in California-based research.

Managing HIV During the COVID-19 Pandemic: A Study of Help-Seeking Behaviors on a Social Media Forum

(2023)

Although numerous editorials claim the COVID-19 pandemic has disproportionately impacted vulnerable populations, particularly those affected by HIV, these claims have received limited empirical evaluation. We analyzed posts to Reddit's r/HIVAIDS from January 3, 2012 through April 30, 2022 to (a) assess changes in the volume of posts during the pandemic and (b) determine the needs of HIV affected communities. There were cumulatively 100% (95%CI: 75-126) more posts than expected since the US declared a pandemic emergency. The most prevalent themes in these posts were for obtaining an HIV + diagnosis (representing 34% (95%CI:29-40) of all posts), seeking HIV treatment (20%; 95%CI:16-25), finding psychosocial support (16%; 95%CI:12-20), and tracking disease progression (8%; 95%CI:5-11). Discussions about PrEP and PEP were the least common, representing less than 6% of all posts each. Social media has increasingly become an important health resource for vulnerable populations seeking information, advice, and support. Public health organizations should recognize how the lay public uses social media and collaborate with social media companies to ensure that the needs of help-seekers on these platforms are met.

Randomized Trial of Individualized Texting for Adherence Building (iTAB) Plus Motivational Interviewing for PrEP Adherence in Transgender Individuals: The iM-PrEPT Study.

(2022)

Background

Transgender and nonbinary individuals at risk for HIV may benefit from adherence support for pre-exposure prophylaxis.

Methods

Between June 2017 and September 2020, 255 transgender and nonbinary individuals received daily oral tenofovir disoproxil fumarate/emtricitabine for 48 weeks randomized 1:1 to receive individualized Texting for Adherence Building (iTAB) or iTAB plus motivational interviewing (iTAB + MI) through phone for nonadherence. The primary end point was dried blood spot tenofovir diphosphate concentrations at weeks 12 and 48 (or last on-drug study visit) ≥1246 fmol/punch consistent with ≥7 doses/week (ie, near-perfect adherence). Secondary outcomes included dried blood spot tenofovir diphosphate concentrations ≥719 fmol/punch consistent with ≥4 doses/week (ie, adequate adherence) and self-reported adherence by daily text messages.

Results

Adherence for the outcome ≥1246 fmol/punch and ≥719 fmol/punch, respectively, was 49.1% and 57.9% for transgender men, 37.7% and 47.2% for nonbinary individuals, and 31.0% and 44.1% for transgender women. No difference was seen in iTAB + MI compared with iTAB alone by drug levels except where it approached significance in transgender women for the outcome of ≥719 fmol/punch in the iTAB + MI group compared with iTAB only (52% versus 35.7%, P = 0.065). There was a significant difference in self-reported daily dose adherence in the iTAB + MI group compared with iTAB alone (57.9% of days versus 46.4%, P = 0.009). In transgender women, the mean percentage of daily doses taken was 58.5% with iTAB + MI and 37.3% with iTAB alone ( P < 0.001).

Conclusions

In addition to automated approaches to adherence promotion, phone-based MI triggered by repeatedly missing doses may improve pre-exposure prophylaxis adherence among transgender women.

Cover page of Low incidence and prevalence of hepatitis C in two cohorts of HIV pre-exposure prophylaxis adherence interventions in men who have sex with men in Southern California.

Low incidence and prevalence of hepatitis C in two cohorts of HIV pre-exposure prophylaxis adherence interventions in men who have sex with men in Southern California.

(2022)

HIV pre-exposure prophylaxis (PrEP) has been associated with incident hepatitis C virus (HCV) infection in men who have sex with men (MSM) due to decreased condom use. We examined rates of HCV among MSM and transgender women at high-risk of HIV on PrEP in Southern California using data from two trials (NCT01761643 and NCT01781806). Five of 599 participants (0.84%, 95% CI, 0.27-1.93) had HCV antibodies detected at entry. Factors associated with HCV seropositivity included being older (p = .002) and lower education level (p < .001). HCV-positive participants had no reported cases of sexually transmitted infection (rectal, urethral or pharyngeal gonorrhoea and/or chlamydia) at entry while HCV-negative participants had a prevalence of 18% (95% CI, 15%-21%). There were no significant differences in substance use and sexual risk behaviour between HCV-positive and HCV-negative participants 1-3 months prior to entry. Among early PrEP adopters, incident HCV did not occur despite ongoing condomless intercourse. Screening intervals for HCV in MSM on PrEP should be led by a risk behaviour assessment.

Cover page of Using Microsimulation Modeling to Inform EHE Implementation Strategies in Los Angeles County

Using Microsimulation Modeling to Inform EHE Implementation Strategies in Los Angeles County

(2022)

Background

Pre-exposure prophylaxis (PrEP) is essential to ending HIV. Yet, uptake remains uneven across racial and ethnic groups. We aimed to estimate the impacts of alternative PrEP implementation strategies in Los Angeles County.

Setting

Men who have sex with men, residing in Los Angeles County.

Methods

We developed a microsimulation model of HIV transmission, with inputs from key local stakeholders. With this model, we estimated the 15-year (2021-2035) health and racial and ethnic equity impacts of 3 PrEP implementation strategies involving coverage with 9000 additional PrEP units annually, above the Status-quo coverage level. Strategies included PrEP allocation equally (strategy 1), proportionally to HIV prevalence (strategy 2), and proportionally to HIV diagnosis rates (strategy 3), across racial and ethnic groups. We measured the degree of relative equalities in the distribution of the health impacts using the Gini index (G) which ranges from 0 (perfect equality, with all individuals across all groups receiving equal health benefits) to 1 (total inequality).

Results

HIV prevalence was 21.3% in 2021 [Black (BMSM), 31.1%; Latino (LMSM), 18.3%, and White (WMSM), 20.7%] with relatively equal to reasonable distribution across groups (G, 0.28; 95% confidence interval [CI], 0.26 to 0.34). During 2021-2035, cumulative incident infections were highest under Status-quo (n = 24,584) and lowest under strategy 3 (n = 22,080). Status-quo infection risk declined over time among all groups but remained higher in 2035 for BMSM (incidence rate ratio, 4.76; 95% CI: 4.58 to 4.95), and LMSM (incidence rate ratio, 1.74; 95% CI: 1.69 to 1.80), with the health benefits equally to reasonably distributed across groups (G, 0.32; 95% CI: 0.28 to 0.35). Relative to Status-quo, all other strategies reduced BMSM-WMSM and BMSM-LMSM disparities, but none reduced LMSM-WMSM disparities by 2035. Compared to Status-quo, strategy 3 reduced the most both incident infections (% infections averted: overall, 10.2%; BMSM, 32.4%; LMSM, 3.8%; WMSM, 3.5%) and HIV racial inequalities (G reduction, 0.08; 95% CI: 0.02 to 0.14).

Conclusions

Microsimulation models developed with early, continuous stakeholder engagement and inputs yield powerful tools to guide policy implementation.

Cover page of Opportunities and challenges for the development of “core outcome sets” in neuro-oncology

Opportunities and challenges for the development of “core outcome sets” in neuro-oncology

(2022)

Core Outcome Sets (COS) define minimum outcomes to be measured and reported in clinical effectiveness trials for a particular health condition/health area. Despite recognition as critical to clinical research design for other health areas, none have been developed for neuro-oncology. COS development projects should carefully consider: scope (how the COS should be used), stakeholders involved in development (including patients as both research partners and participants), and consensus methodologies used (typically a Delphi survey and consensus meeting), as well as dissemination plans. Developing COS for neuro-oncology is potentially challenging due to extensive tumor subclassification (including molecular stratification), different symptoms related to anatomical tumor location, and variation in treatment options. Development of a COS specific to tumor subtype, in a specific location, for a particular intervention may be too narrow and would be unlikely to be used. Equally, a COS that is applicable across a wider area of neuro-oncology may be too broad and therefore lack specificity. This review describes why and how a COS may be developed, and discusses challenges for their development, specific to neuro-oncology. The COS under development are briefly described, including: adult glioma, incidental/untreated meningioma, meningioma requiring intervention, and adverse events from surgical intervention for pediatric brain tumors.

Method of Calculating Renal Function Estimates Could Inappropriately Exclude Transgender Patients Receiving Gender-Affirming Hormone Therapy from Pre-Exposure Prophylaxis Eligibility.

(2022)

Purpose: Despite the importance of reliable renal function estimation among the growing transgender population, research describing the variability of existing equations is scarce. Study objectives were to (1) quantify the range of renal function estimates that would be observed if different gender coefficients are used in the estimating equations, (2) compare estimates of renal function (creatinine clearance [CLCR] or estimated glomerular filtration rate [GFR]) between users and nonusers of gender-affirming therapies, and (3) quantify the proportion of subjects who would be deemed ineligible for tenofovir disoproxil fumarate/emtricitabine (TDF/FTC) for pre-exposure prophylaxis (PrEP) based on the gender coefficient used. Methods: A retrospective analysis was performed among transgender PrEP users enrolled in a multicenter observational study between June 2017 and October 2021. The primary outcome was estimated kidney function, defined using calculated CLCR or GFR before initiating TDF/FTC for PrEP based on the three most commonly used estimating equations. Results: A total of 258 participants were evaluated. Median differences in renal function ranged from 13 to 25 mL/min based on which gender coefficient and equation was used. Regardless of the method used to compute renal function, there were significant differences between users and nonusers of gender-affirming therapy. There were 17 (6.6%) participants where at least one of the methods would potentially render them ineligible to receive TDF/FTC for PrEP. Conclusions: Renal function estimates vary considerably with different estimating equations in the transgender population and are modified by use of gender-affirming therapy. These variations could result in exclusion from drug therapies such as TDF/FTC for PrEP.

Cover page of Hypoxia Is a Dominant Remodeler of the Effector T&nbsp;Cell Surface Proteome Relative to Activation and Regulatory T Cell Suppression.

Hypoxia Is a Dominant Remodeler of the Effector T Cell Surface Proteome Relative to Activation and Regulatory T Cell Suppression.

(2022)

Immunosuppressive factors in the tumor microenvironment (TME) impair T cell function and limit the antitumor immune response. T cell surface receptors and surface proteins that influence interactions and function in the TME are proven targets for cancer immunotherapy. However, how the entire surface proteome remodels in primary human T cells in response to specific suppressive factors in the TME remains to be broadly and systematically characterized. Here, using a reductionist cell culture approach with primary human T cells and stable isotopic labeling with amino acids in cell culture-based quantitative cell surface capture glycoproteomics, we examined how two immunosuppressive TME factors, regulatory T cells (Tregs) and hypoxia, globally affect the activated CD8+ surface proteome (surfaceome). Surprisingly, coculturing primary CD8+ T cells with Tregs only modestly affected the CD8+ surfaceome but did partially reverse activation-induced surfaceomic changes. In contrast, hypoxia drastically altered the CD8+ surfaceome in a manner consistent with both metabolic reprogramming and induction of an immunosuppressed state. The CD4+ T cell surfaceome similarly responded to hypoxia, revealing a common hypoxia-induced surface receptor program. Our surfaceomics findings suggest that hypoxic environments create a challenge for T cell activation. These studies provide global insight into how Tregs and hypoxia remodel the T cell surfaceome and we believe represent a valuable resource to inform future therapeutic efforts to enhance T cell function.

Cover page of Sexually transmitted infections among participants in an HIV PrEP adherence trial.

Sexually transmitted infections among participants in an HIV PrEP adherence trial.

(2022)

Background

HIV PrEP effectiveness is highly dependent on adherence. High STI incidence has been reported among PrEP users. We assessed the relationship between STI incidence (CT, NG, and syphilis) and PrEP adherence.

Methods

We performed a subanalysis of a controlled, open-label, two-arm, randomized clinical demonstration project of a text-message based adherence intervention. Participants had 48 weeks of follow-up and had STI testing every 12 or 24 weeks. PrEP adherence was measured at week 48 using intracellular tenofovir-diphosphate drug concentrations. We calculated incidence rate ratios for STIs among those adherent as compared with those not adherent to PrEP.

Results

Of the 381 assessed for CT, NG and syphilis at one or more follow-up visits, there were 16 cases of syphilis or 5.0 per 100 person years (95% CI: 2.6, 7.5); 63 cases of NG or 26.3 per 100 person years (95% CI: 19.8, 32.8); and 81 cases of CT or 36.3 per 100 person years (95% CI: 28.4, 44.2). We found no association between adequate PrEP adherence and STI incidence (aIRR: 0.97 95% CI: 0.67, 1.40).

Conclusions

We found that the incidence of STIs was not significantly different between those adherent to PrEP and those non-adherent. Further research is needed to assess how PrEP use may impact STIs over time.

Cover page of Disparities In Uptake Of HIV Pre-Exposure Prophylaxis Among California Medicaid Enrollees.

Disparities In Uptake Of HIV Pre-Exposure Prophylaxis Among California Medicaid Enrollees.

(2022)

One of the pillars of efforts in the US to curb HIV incidence is pre-exposure prophylaxis (PrEP). We examined racial/ethnic and sex disparities in PrEP uptake among California Medicaid enrollees. Claims data from 2019 identified enrollees and PrEP users in each racial/ethnic, sex, and age group, yielding crude uptake rates. We then predicted age-adjusted uptake rates from multivariable logit regressions and divided PrEP uptake estimates by each group's number of new HIV diagnoses to estimate PrEP-to-need ratios. Predicted uptake was highest for White (0.29 percent) and Black (0.23 percent) males and lowest (0.16 percent) for Hispanic males. Rates for males exceeded those for females; however, Black females had twice the rate of PrEP uptake of White females. Black males and females and Hispanic males had PrEP-to-need ratios that were less than one-third (4.0-6.3) those of Asian and White males and females (14.4-19.9). Low PrEP use rates and disparities in uptake threaten efforts to end the HIV epidemic. Policy makers must craft the rollout of innovations such as PrEP in a manner that narrows HIV disparities instead of widening them.

  • 1 supplemental ZIP
Cover page of CRISPR–Cas9-mediated nuclear transport and genomic integration of nanostructured genes in human primary cells

CRISPR–Cas9-mediated nuclear transport and genomic integration of nanostructured genes in human primary cells

(2022)

DNA nanostructures are a promising tool to deliver molecular payloads to cells. DNA origami structures, where long single-stranded DNA is folded into a compact nanostructure, present an attractive approach to package genes; however, effective delivery of genetic material into cell nuclei has remained a critical challenge. Here, we describe the use of DNA nanostructures encoding an intact human gene and a fluorescent protein encoding gene as compact templates for gene integration by CRISPR-mediated homology-directed repair (HDR). Our design includes CRISPR-Cas9 ribonucleoprotein binding sites on DNA nanostructures to increase shuttling into the nucleus. We demonstrate efficient shuttling and genomic integration of DNA nanostructures using transfection and electroporation. These nanostructured templates display lower toxicity and higher insertion efficiency compared to unstructured double-stranded DNA templates in human primary cells. Furthermore, our study validates virus-like particles as an efficient method of DNA nanostructure delivery, opening the possibility of delivering nanostructures in vivo to specific cell types. Together, these results provide new approaches to gene delivery with DNA nanostructures and establish their use as HDR templates, exploiting both their design features and their ability to encode genetic information. This work also opens a door to translate other DNA nanodevice functions, such as biosensing, into cell nuclei.