Publications by authors named "Peter de Hoff"

Background: SARS-CoV-2 antibody levels have been proposed as a correlate of protection (CoP) from infection. Yet, large-scale prospective studies of cost-effective scalable antibody measures as predictors of infection under real-world conditions are limited. We examined whether antibody levels measured using high-throughput variant-specific SARS-CoV-2 anti-spike immunoglobulin G (IgG) and ACE2-neutralization assays correlate with cell-based neutralizing antibody (NAb) measurements, and whether they can serve as a reasonable CoP from SARS-CoV-2 infection.

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Earlier studies have revealed microRNAs (miRNAs) as potential biomarkers for neurological conditions, however, such evidence on psychiatric outcomes is limited. We utilized the Normative Aging Study (NAS) cohort to investigate the associations between extracellular miRNAs (ex-miRNA) and psychiatric symptoms among a group of older male adults, along with the targeted genes and biological pathways. We studied 569 participants with miRNA profile primarily measured in extracellular vesicles isolated from plasma, and psychiatric symptoms reported over 1996-2014 with repeated measures.

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Background: American Indian populations have experienced marked disparities in respiratory disease burden. Extracellular vesicle-encapsulated microRNAs (EV-miRNAs) are a novel class of biomarkers that may improve recognition of lung damage in indigenous populations in the United States.

Research Question: Are plasma EV-miRNAs viable biomarkers of respiratory health in American Indian populations?

Study Design And Methods: The Strong Heart Study is a prospective cohort study that enrolled American Indian patients aged 45 to 74 years.

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Background: Mechanistic studies of the effects of environmental risk factors have been exploring the potential role of microRNA(miRNAs) as a possible pathway to clinical disease. In this study we examine whether levels of toenail metals are associated with changes in extracellular miRNA(ex-miRNA) expression.

Methods: We used data derived from the Normative Aging Study from 1996 to 2014 to conduct our analyses.

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Antibodies are critical tools for research into extracellular vesicles (EVs) and other extracellular nanoparticles (ENPs), where they can be used for their identification, characterization, and isolation. However, the lack of a centralized antibody platform where researchers can share validation results thus minimizing wasted personnel time and reagents, has been a significant obstacle. Moreover, because the performance of antibodies varies among assay types and conditions, detailed information on assay variables and protocols is also of value.

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Background: Infection prevention (IP) measures are designed to mitigate the transmission of pathogens in healthcare. Using large-scale viral genomic and social network analyses, we determined if IP measures used during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic were adequate in protecting healthcare workers (HCWs) and patients from acquiring SARS-CoV-2.

Methods: We performed retrospective cross-sectional analyses of viral genomics from all available SARS-CoV-2 viral samples collected at UC San Diego Health and social network analysis using the electronic medical record to derive temporospatial overlap of infections among related viromes and supplemented with contact tracing data.

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We report on the identification of extracellular miRNA (ex-miRNA) biomarkers for early diagnosis and prognosis of preeclampsia (PE). Small RNA sequencing of maternal serum prospectively collected from participants undergoing evaluation for suspected PE revealed distinct patterns of ex-miRNA expression among different categories of hypertensive disorders in pregnancy. Applying an iterative machine learning method identified three bivariate miRNA biomarkers (, , and ) that, when applied serially, distinguished between PE cases of different severity and differentiated cases from controls with a sensitivity of 93%, specificity of 79%, positive predictive value (PPV) of 55%, and negative predictive value (NPV) of 89%.

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The maturation of genomic surveillance in the past decade has enabled tracking of the emergence and spread of epidemics at an unprecedented level. During the COVID-19 pandemic, for example, genomic data revealed that local epidemics varied considerably in the frequency of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) lineage importation and persistence, likely due to a combination of COVID-19 restrictions and changing connectivity. Here, we show that local COVID-19 epidemics are driven by regional transmission, including across international boundaries, but can become increasingly connected to distant locations following the relaxation of public health interventions.

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Background: Immune changes that occur during pregnancy may place pregnant women at an increased risk for severe disease following viral infections like SARS-CoV-2. Whether these immunologic changes modify the immune response to SARS-CoV-2 infection during pregnancy is not well understood.

Objective: This study aimed to compare the humoral immune response to SARS-CoV-2 infection in pregnant and nonpregnant women.

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Background: The molecular effects of intermediate and long-term exposure to air pollution and temperature, such as those on extracellular microRNA (ex-miRNA) are not well understood but may have clinical consequences.

Objectives: To assess the association between exposure to ambient air pollution and temperature and ex-miRNA profiles.

Methods: Our study population consisted of 734 participants in the Normative Aging Study (NAS) between 1999 and 2015.

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Background: Schools are high-risk settings for SARS-CoV-2 transmission, but necessary for children's educational and social-emotional wellbeing. Previous research suggests that wastewater monitoring can detect SARS-CoV-2 infections in controlled residential settings with high levels of accuracy. However, its effective accuracy, cost, and feasibility in non-residential community settings is unknown.

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Background: While the health effects of air pollution and temperature are widely studied, the molecular effects are poorly understood. Extracellular microRNAs (ex-miRNAs) have the potential to serve as diagnostic or prognostic biomarkers and/or to act as intercellular signaling molecules that mediate the effects of environmental exposures on health outcomes.

Methods: We examined the relationship between short-term exposure to air pollution and ambient temperature and the ex-miRNA profiles of participants in the Normative Aging Study (NAS) from 1999 to 2015.

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Background: Aging-related cognitive decline is an early symptom of Alzheimer's disease and other dementias, and on its own can have substantial consequences on an individual's ability to perform important everyday functions. Despite increasing interest in the potential roles of extracellular microRNAs (miRNAs) in central nervous system (CNS) pathologies, there has been little research on extracellular miRNAs in early stages of cognitive decline. We leverage the longitudinal Normative Aging Study (NAS) cohort to investigate associations between plasma miRNAs and cognitive function among cognitively normal men.

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The extracellular RNA communication consortium (ERCC) is an NIH-funded program aiming to promote the development of new technologies, resources, and knowledge about exRNAs and their carriers. After Phase 1 (2013-2018), Phase 2 of the program (ERCC2, 2019-2023) aims to fill critical gaps in knowledge and technology to enable rigorous and reproducible methods for separation and characterization of both bulk populations of exRNA carriers and single EVs. ERCC2 investigators are also developing new bioinformatic pipelines to promote data integration through the exRNA atlas database.

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Early detection of respiratory diseases is critical to facilitate delivery of disease-modifying interventions. Extracellular vesicle-enriched microRNAs (EV-miRNAs) may represent reliable markers of early lung injury. Evaluate associations of plasma EV-miRNAs with lung function.

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Article Synopsis
  • Effective detection of SARS-CoV-2 variants through wastewater analysis can complement existing clinical testing methods, especially in resource-limited areas where traditional testing may be biased.* -
  • The study implemented improved virus concentration techniques and software to enhance the sequencing of multiple virus strains from wastewater, resulting in high-resolution data over 295 days at a university and its surrounding county.* -
  • Wastewater surveillance identified emerging variants up to 14 days earlier than clinical methods and revealed instances of virus spread that clinical testing missed, highlighting its potential for public health monitoring.*
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Surface sampling for SARS-CoV-2 RNA detection has shown considerable promise to detect exposure of built environments to infected individuals shedding virus who would not otherwise be detected. Here, we compare two popular sampling media (VTM and SDS) and two popular workflows (Thermo and PerkinElmer) for implementation of a surface sampling program suitable for environmental monitoring in public schools. We find that the SDS/Thermo pipeline shows superior sensitivity and specificity, but that the VTM/PerkinElmer pipeline is still sufficient to support surface surveillance in any indoor setting with stable cohorts of occupants (e.

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  • A study investigates using sentinel cards for monitoring SARS-CoV-2 traces in indoor environments, especially schools, to support safe in-person learning.* -
  • The research tests various cleaning solutions to maintain the effectiveness of these cards while preventing interference from previously detected viral loads.* -
  • RNase Away proved the best cleaner for all conditions, helping differentiate between new infections and residual virus, thereby offering a practical monitoring solution in settings with privacy concerns.*
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Article Synopsis
  • Monitoring SARS-CoV-2 on surfaces can help identify past exposure, especially in places like hospitals and schools, by detecting viral RNA left by infected individuals.
  • A study collected samples from isolation housing units to investigate where SARS-CoV-2 accumulates, finding high viral loads on frequently touched surfaces like light switches but also on untouched ones like floors.
  • The bacterial community in these environments seems to predict the presence of SARS-CoV-2, suggesting a potential link between certain bacterial types and higher viral detection.
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As SARS-CoV-2 continues to spread and evolve, detecting emerging variants early is critical for public health interventions. Inferring lineage prevalence by clinical testing is infeasible at scale, especially in areas with limited resources, participation, or testing/sequencing capacity, which can also introduce biases. SARS-CoV-2 RNA concentration in wastewater successfully tracks regional infection dynamics and provides less biased abundance estimates than clinical testing.

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Throughout the COVID-19 pandemic, massive sequencing and data sharing efforts enabled the real-time surveillance of novel SARS-CoV-2 strains throughout the world, the results of which provided public health officials with actionable information to prevent the spread of the virus. However, with great sequencing comes great computation, and while cloud computing platforms bring high-performance computing directly into the hands of all who seek it, optimal design and configuration of a cloud compute cluster requires significant system administration expertise. We developed ViReflow, a user-friendly viral consensus sequence reconstruction pipeline enabling rapid analysis of viral sequence datasets leveraging Amazon Web Services (AWS) cloud compute resources and the Reflow system.

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Article Synopsis
  • - Monitoring the presence of SARS-CoV-2 on surfaces helps to identify past exposures to infected individuals, assisting in tracking the virus’s spread, particularly in areas like hospitals and schools.
  • - Research indicates that the highest viral loads are found on frequently touched surfaces (e.g., light switches, faucets), with detectable levels also present on non-touched surfaces, making sampling strategies important for environments where people are mask-wearing.
  • - The study also linked SARS-CoV-2 levels to the surrounding bacterial community, finding that certain bacterial species can predict the likelihood of samples being positive for the virus, emphasizing the relationship between surface type and viral presence.
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Article Synopsis
  • - Environmental monitoring can help identify surfaces contaminated with COVID-19, providing crucial data for infection control and quarantine measures.
  • - Research shows that the detection of viral RNA using RT-qPCR on surfaces remains stable for up to 7 days, with differences in signal intensity based on surface material (rough vs. smooth).
  • - These findings highlight the need for cleaning surfaces after sampling to track virus decay and indicate that heat-inactivated viral particles can improve the efficiency of environmental monitoring in public health settings.
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Background: Schools are high-risk settings for SARS-CoV-2 transmission, but necessary for children's educational and social-emotional wellbeing. Previous research suggests that wastewater monitoring can detect SARS-CoV-2 infections in controlled residential settings with high levels of accuracy. However, its effective accuracy, cost, and feasibility in non-residential community settings is unknown.

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Article Synopsis
  • The COVID-19 epidemic in the U.S. went largely unnoticed due to a lack of testing, with New Orleans experiencing one of the earliest outbreaks during Mardi Gras.
  • Researchers sequenced SARS-CoV-2 genomes in Louisiana and found that the virus had limited diversity, indicating a single introduction led to most early cases.
  • The study revealed that SARS-CoV-2 was likely present in New Orleans before Mardi Gras, and the event significantly contributed to the rapid spread of the virus, highlighting the impact of large gatherings on epidemics.
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