A review of MPTP-induced parkinsonism in adult zebrafish to explore pharmacological interventions for human Parkinson's disease.

Novel work in adult zebrafish, Danio rerio, to recapitulate human neurodegenerative disease has proven useful in both pharmaceutical development and research on genetic disease. Due to high genetic homology to humans, affordable husbandry, relatively quick life cycle breeding times, and robust embryo production, zebrafish offer a promising model to test pharmaceutical performance in a high throughput, in vivo setting. Currently, most research in zebrafish models of Parkinson's disease induces the disease in larval or embryonic stage organisms due to ease of administration, with advancement through developmental stages taking only a matter of days. The use of early-stage organisms limits the usability of zebrafish as models for adult disease and specifically age-related neurodegenerative conditions. Recently, researchers have sought to extend the usability of zebrafish into models for Parkinson's disease. Specifically, 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) has emerged as a prodrug that upon injection well-encompasses the biochemical mechanisms and symptomology associated with Parkinson's disease. By utilizing MPTP in an adult zebrafish model, advancements in Parkinson's disease research may be achieved. This paper highlights the recent research on this model, comparing it to the human form of Parkinson's disease.

Therapeutic developments for neurodegenerative GM1 gangliosidosis.

GM1 gangliosidosis (GM1) is a rare but fatal neurodegenerative disease caused by dysfunction or lack of production of lysosomal enzyme, ß-galactosidase, leading to accumulation of substrates. The most promising treatments for GM1, include enzyme replacement therapy (ERT), substrate reduction therapy (SRT), stem cell therapy and gene editing. However, effectiveness is limited for neuropathic GM1 due to the restrictive nature of the blood-brain barrier (BBB). ERT and SRT alleviate substrate accumulation through exogenous supplementation over the patient's lifetime, while gene editing could be curative, fixing the causative gene, GLB1, to enable endogenous enzyme activity. Stem cell therapy can be a combination of both, with ex vivo gene editing of cells to cause the production of enzymes. These approaches require special considerations for brain delivery, which has led to novel formulations. A few therapeutic interventions have progressed to early-phase clinical trials, presenting a bright outlook for improved clinical management for GM1.

Bridging clinical radiotherapy and space radiation therapeutics through reactive oxygen species (ROS)-triggered delivery.

This review explores the convergence of clinical radiotherapy and space radiation therapeutics, focusing on ionizing radiation (IR)-generated reactive oxygen species (ROS). IR, with high-energy particles, induces precise cellular damage, particularly in cancer treatments. The paper discusses parallels between clinical and space IR, highlighting unique characteristics of high-charge and energy particles in space and potential health risks for astronauts. Emphasizing the parallel occurrence of ROS generation in both clinical and space contexts, the review identifies ROS as a crucial factor with dual roles in cellular responses and potential disease initiation. The analysis covers ROS generation mechanisms, variations, and similarities in terrestrial and extraterrestrial environments leading to innovative ROS-responsive delivery systems adaptable for both clinical and space applications. The paper concludes by discussing applications of personalized ROS-triggered therapeutic approaches and discussing the challenges and prospects of implementing these strategies in clinical radiotherapy and extraterrestrial missions. Overall, it underscores the potential of ROS-targeted delivery for advancing therapeutic strategies in terrestrial clinical settings and space exploration, contributing to human health improvement on Earth and beyond.

Optimizing enzyme-responsive polymersomes for protein-based therapies.

Aims: Stimuli-responsive polymersomes are promising tools for protein-based therapies, but require deeper understanding and optimization of their pathology-responsive behavior. Materials & methods: Hyaluronic acid (HA)-poly(b-lactic acid) (PLA) polymersomes self-assembled from block copolymers of varying molecular weights of HA were compared for their physical properties, degradation and intracellular behavior. Results: Major results showed increasing enzyme-responsivity associated with decreasing molecular weight. The major formulation differences were as follows: the HA(5 kDa)-PLA formulation exhibited the most pronounced release of encapsulated proteins, while the HA(7 kDa)-PLA formulation showed the most different release behavior from neutral. Conclusion: We have discovered design rules for HA-PLA polymersomes for protein delivery, with lower molecular weight leading to higher encapsulation efficiency, greater release and greater intracellular uptake.

Nanoparticle-mediated delivery of non-viral gene editing technology to the brain.

Neurological disorders pose a significant burden on individuals and society, affecting millions worldwide. These disorders, including but not limited to Alzheimer's disease, Parkinson's disease, and Huntington's disease, often have limited treatment options and can lead to progressive degeneration and disability. Gene editing technologies, including Zinc Finger Nucleases (ZFN), Transcription Activator-Like Effector Nucleases (TALEN), and Clustered Regularly Interspaced Short Palindromic Repeats-associated Protein 9 (CRISPR-Cas9), offer a promising avenue for potential cures by targeting and correcting the underlying genetic mutations responsible for neurologic disorders. However, efficient delivery methods are crucial for the successful application of gene editing technologies in the context of neurological disorders. The central nervous system presents unique challenges to treatment development due to the blood-brain barrier, which restricts the entry of large molecules. While viral vectors are traditionally used for gene delivery, nonviral delivery methods, such as nanoparticle-mediated delivery, offer safer alternatives that can efficiently transport gene editing components. Herein we aim to introduce the three main gene editing nucleases as nonviral treatments for neurologic disorders, the delivery barriers associated with brain targeting, and the current nonviral techniques used for brain-specific delivery. We highlight the challenges and opportunities for future research in this exciting and growing field that could lead to blood-brain barrier bypassing therapeutic gene editing.

Complex Coacervates as a Promising Vehicle for mRNA Delivery: A Comprehensive Review of Recent Advances and Challenges.

Messenger RNA (mRNA)-based therapies have gained significant attention, following the successful deployment of mRNA-based COVID-19 vaccines. Compared with traditional methods of genetic modification, mRNA-based therapies offer several advantages, including a lower risk of genetic mutations, temporary and controlled therapeutic gene expression, and a shorter production time, which facilitates rapid responses to emerging health challenges. Moreover, mRNA-based therapies have shown immense potential in treating a wide range of diseases including cancers, immune diseases, and neurological disorders. However, the current limitations of non-viral vectors for efficient and safe delivery of mRNA therapies, such as low encapsulation efficiency, potential toxicity, and limited stability, necessitate the exploration of novel strategies to overcome these challenges and fully realize the potential of mRNA-based therapeutics. Coacervate-based delivery systems have recently emerged as promising strategies for enhancing mRNA delivery. Coacervates, which are formed by the aggregation of two or more macromolecules, have shown great potential in delivering a wide range of therapeutics due to their ability to form a separated macromolecular-rich fluid phase in an aqueous environment. This phase separation enables the entrapment and protection of therapeutic agents from degradation as well as efficient cellular uptake and controlled release. Additionally, the natural affinity of coacervates for mRNA molecules presents an excellent opportunity for enhancing mRNA delivery to targeted cells and tissues, making coacervate-based delivery systems an attractive option for mRNA-based therapies. This review highlights the limitations of current strategies for mRNA delivery and the advantages of coacervate-based delivery systems to enable mRNA therapeutics. Coacervates protect mRNA from enzymatic degradation and enhance cellular uptake, leading to sustained and controlled gene expression. Despite their promising properties, the specific use of coacervates as mRNA delivery vehicles remains underexplored. This review aims to provide a comprehensive overview of coacervate-mediated delivery of mRNA, exploring the properties and applications of different coacervating agents as well as the challenges and optimization strategies involved in mRNA encapsulation, release, stability, and translation via coacervate-mediated delivery. Through a comprehensive analysis of recent advancements and recommended future directions, our review sheds light on the promising role of coacervate-mediated delivery for RNA therapeutics, highlighting its potential to enable groundbreaking applications in drug delivery and gene therapy.

The Impact of MiR-33a-5p Inhibition in Pro-Inflammatory Endothelial Cells.

Evidence suggests cholesterol accumulation in pro-inflammatory endothelial cells (EC) contributes to triggering atherogenesis and driving atherosclerosis progression. Therefore, inhibiting miR-33a-5p within inflamed endothelium may prevent and treat atherosclerosis by enhancing apoAI-mediated cholesterol efflux by upregulating ABCA1. However, it is not entirely elucidated whether inhibition of miR-33a-5p in pro-inflammatory EC is capable of increasing ABCA1-dependent cholesterol efflux. In our study, we initially transfected LPS-challenged, immortalized mouse aortic EC (iMAEC) with either pAntimiR33a5p plasmid DNA or the control plasmid, pScr. We detected significant increases in both ABCA1 protein expression and apoAI-mediated cholesterol efflux in iMAEC transfected with pAntimiR33a5p when compared to iMAEC transfected with pScr. We subsequently used polymersomes targeting inflamed endothelium to deliver either pAntimiR33a5p or pScr to cultured iMAEC and showed that the polymersomes were selective in targeting pro-inflammatory iMAEC. Moreover, when we exposed LPS-challenged iMAEC to these polymersomes, we observed a significant decrease in miR-33a-5p expression in iMAEC incubated with polymersomes containing pAntimR33a5p versus control iMAEC. We also detected non-significant increases in both ABCA1 protein and apoAI-mediated cholesterol in iMAEC exposed to polymersomes containing pAntimR33a5p when compared to control iMAEC. Based on our results, inhibiting miR-33a-5p in pro-inflammatory EC exhibits atheroprotective effects, and so precisely delivering anti-miR-33a-5p to these cells is a promising anti-atherogenic strategy.

A randomized controlled trial for a peer-facilitated telemedicine hepatitis c treatment intervention for people who use drugs in rural communities: study protocol for the "peer tele-HCV" study.

BACKGROUND: Hepatitis C virus (HCV) transmission is primarily driven by injection drug use, and acute HCV infection rates are increased in rural communities with substantial barriers to care. Treatment of HCV in persons who use drugs (PWUD) is cost effective, decreases high risk behaviors and HCV transmission, and achieves high rates of treatment completion and sustained viral response. Adapting HCV care delivery to utilize peer support specialists, telemedicine technology, and streamlined testing and treatment strategies can better reach rural populations living with HCV. METHODS: This is an open label, two-arm, non-blinded, randomized controlled trial designed to test the superiority of peer-facilitated and streamlined telemedicine HCV care (peer tele-HCV) compared to enhanced usual care (EUC) among PWUD in rural Oregon. In the intervention arm, peers conduct HCV screening in the community, facilitate pretreatment evaluation and linkage to telemedicine hepatitis C treatment providers, and support participants in HCV medication adherence. For participants assigned to EUC, peers facilitate pretreatment evaluation and referral to community-based treatment providers. The primary outcome is sustained virologic response at 12 weeks post treatment (SVR12). Secondary outcomes include: (1) HCV treatment initiation, (2) HCV treatment completion, (3) engagement with harm reduction resources, (4) rates of substance use, and (5) engagement in addiction treatment resources. The primary and secondary outcomes are analyzed using intention-to-treat (ITT) comparisons between telemedicine and EUC. A qualitative analysis will assess patient, peer, and clinician experiences of peer-facilitated telemedicine hepatitis C treatment. DISCUSSION: This study uses a novel peer-based telemedicine delivery model with streamlined testing protocols to improve access to HCV treatment in rural communities with high rates of injection drug use and ongoing disease transmission. We hypothesize that the peer tele-HCV model will increase treatment initiation, treatment completion, SVR12 rates, and engagement with harm reduction services compared to EUC. Trial registration This trial has been registered with ClinicalTrials.gov (clinicaltrials.gov NCT04798521).

Polymeric Metal Contrast Agents for T1-Weighted Magnetic Resonance Imaging of the Brain.

Imaging plays an integral role in diagnostics and treatment monitoring for conditions affecting the brain; enhanced brain imaging capabilities will improve upon both while increasing the general understanding of how the brain works. T1-weighted magnetic resonance imaging is the preferred modality for brain imaging. Commercially available contrast agents, which are often required to render readable brain images, have considerable toxicity concerns. In recent years, much progress has been made in developing new contrast agents based on the magnetic features of gadolinium, iron, or magnesium. Nanotechnological approaches for these systems allow for the protected integration of potentially harmful metals with added benefits like reduced dosage and improved transport. Polymeric enhancement of each design further improves biocompatibility while allowing for specific brain targeting. This review outlines research on polymeric nanomedicine designs for T1-weighted contrast agents that have been evaluated for performance in the brain.

Knowledge, attitudes, and behaviors related to the fentanyl-adulterated drug supply among people who use drugs in Oregon.

INTRODUCTION: Nonpharmaceutical fentanyl has reconfigured the U.S. illicit drug market, contributing to a drastic increase in overdose drug deaths. While illicit fentanyl has subsumed the drug supply in the Northeast and Midwest, it has more recently reached the West. For this study, we explored knowledge, attitudes, and behaviors among people who use drugs in Oregon in the context of the emergence of fentanyl in the drug supply. METHODS: We conducted in-depth interviews by phone with 34 people who use drugs in Oregon from May to June 2021. We used thematic analysis to analyze transcripts and construct themes. RESULTS: People who use drugs knew about fentanyl, expressed doubt that fentanyl could be found in methamphetamine; believed those who were younger or less experienced were at higher risk for harm; and received information about fentanyl from drug dealers, syringe service programs, or peers (other people who use drugs). Preference for fentanyl's presence in drugs like heroin or methamphetamine was mixed. Some felt that their preference was irrelevant since fentanyl was unavoidable. Participants reported engaging in harm reduction practices, including communicating about fentanyl with dealers and peers, testing for fentanyl, using smaller quantities of drugs, switching from injecting to smoking, and using naloxone. CONCLUSION: People who use drugs are responding to the rise of fentanyl on the West Coast and are concerned about the increasing uncertainty and hazards of the drug supply. They are willing and motivated to adopt harm reduction behaviors. Harm reduction promotion from syringe service programs and public health agencies is essential to reduce injury and death from nonpharmaceutical fentanyl.

"It wasn't here, and now it is. It's everywhere": fentanyl's rising presence in Oregon's drug supply.

BACKGROUND: Illicit fentanyl has contributed to a drastic increase in overdose drug deaths. While fentanyl has subsumed the drug supply in the Northeastern and Midwestern USA, it has more recently reached the Western USA. For this study, we explored perspectives of people who use drugs (PWUD) on the changing drug supply in Oregon, experiences of and response to fentanyl-involved overdose, and recommendations from PWUD to reduce overdose risk within the context of illicit fentanyl's dramatic increase in the recreational drug supply over the past decade. METHODS: We conducted in-depth interviews by phone with 34 PWUD in Oregon from May to June of 2021. We used thematic analysis to analyze transcripts and construct themes. RESULTS: PWUD knew about fentanyl, expressed concern about fentanyl pills, and were aware of other illicit drugs containing fentanyl. Participants were aware of the increased risk of an overdose but remained reluctant to engage with professional first responders due to fear of arrest. Participants had recommendations for reducing fentanyl overdose risk, including increasing access to information, harm reduction supplies (e.g., naloxone, fentanyl test strips), and medications for opioid use disorder; establishing drug checking services and overdose prevention sites; legalizing and regulating the drug supply; and reducing stigma enacted by healthcare providers. CONCLUSION: PWUD in Oregon are aware of the rise of fentanyl and fentanyl pills and desire access to tools to reduce harm from fentanyl. As states in the Western USA face an inflection point of fentanyl in the drug supply, public health staff, behavioral health providers, and first responders can take action identified by the needs of PWUD.

COVID-19 Vaccination Status and Concerns Among People Who Use Drugs in Oregon.

OBJECTIVES: The objective of this study was to examine COVID-19 vaccination acceptance and explore reasons for COVID-19 vaccine hesitancy among people who use drugs (PWUDs), a population with increased COVID-19 transmission and morbidity. METHODS: We conducted semi-structured in-depth interviews with PWUDs in 7 Oregon counties from May 11 to June 25, 2021. Participants (n = 34) were recruited in partnership with syringe service programs and local community organizations staff, participant-referrals, and flyer advertising. Research staff conducted interviews via telephone to assess participants' acceptance of the COVID-19 vaccine, find knowledge gaps where new educational information about vaccination would be helpful, and identify who would be perceived as a trustworthy source of information. Interviews were transcribed and coded using thematic analysis with a deductive approach. RESULTS: Most participants had not received the COVID-19 vaccine and were not planning on or were unsure about receiving it. Participants were mistrustful of the rapid COVID-19 vaccine development process, the agencies involved in the development, and vaccines in general. Participants shared varied and contrasting responses about who they would trust to provide information about the COVID-19 vaccine, including peer recovery support specialists, doctors, or other health care professionals, and specified federal agencies or media outlets. CONCLUSIONS: As addiction medicine and public health staff continue to respond to the evolving impacts of COVID-19, vaccination planning should be tailored to the unique needs of PWUD to increase COVID-19 vaccine acceptance in this high-risk population.

Toward enzyme-responsive polymersome drug delivery.

In drug delivery, enzyme-responsive drug carriers are becoming increasingly relevant because of the growing association of disease pathology with enzyme overexpression. Polymersomes are of interest to such applications because of their tunable properties. While polymersomes open up a wide range of chemical and physical properties to explore, they also present a challenge in developing generalized rules for the synthesis of novel systems. Motivated by this issue, in this perspective, we summarize the existing knowledge on enzyme-responsive polymersomes and outline the main design choices. Then, we propose heuristics to guide the design of novel systems. Finally, we discuss the potential of an integrated approach using computer simulations and experimental studies to streamline this design process and close the existing knowledge gaps.

Prenatal maternal posttraumatic stress disorder as a risk factor for adverse birth weight and gestational age outcomes: A systematic review and meta-analysis.

BACKGROUND: Although not routinely assessed, prenatal posttraumatic stress disorder (PTSD) is associated with poor maternal mental health and mother-infant bonding. Prenatal PTSD may also be associated with birth weight and gestational age outcomes, but this remains unclear. This systematic review and meta-analysis investigated the association of prenatal PTSD with risk of low birth weight (LBW) or preterm birth (PTB) (dichotomous medically-defined cut-offs) or with birth weight (BW) or gestational age (GA) (continuous variables). METHODS: A comprehensive literature search was conducted in Web of Science, MedLine, PubMed, and PsychInfo. Data were collected and processed according to Meta-analysis of Observational Studies in Epidemiology (MOOSE) guidelines. Study quality was assessed with the Newcastle-Ottowa Quality Assessment Scale. Pooled effect sizes were estimated with random-effects models (correlation for continuous and odds ratios for dichotomous outcomes). RESULTS: Sixteen studies with 51,470 participants (prenatal PTSD 8%) were included in 4 meta-analyses. Maternal prenatal PTSD was associated with higher risks of LBW (OR = 1.96; 95% CI, 1.26, 3.03; P = .003), PTB (OR = 1.42; 95% CI, 1.16, 1.73; P = .001), and reduced GA (r = -0.04; 95% CI, -0.06, -0.01; P = .002). LIMITATIONS: Different designs across studies, variety of PTSD assessment practices, and a small pool of studies were noted. CONCLUSIONS: Findings suggest prenatal PTSD presents increased risks of LBW, PTB, and reduced GA. Evidence of physical harm to neonates from prenatal PTSD provides a powerful rationale to increase prenatal PTSD screening and identify effective prenatal interventions to improve maternal and child outcomes.

Modulating Shape of Polyester Based Polymersomes using Osmotic Pressure.

Polymersomes are membrane-bound, bilayer vesicles created from amphiphilic block copolymers that can encapsulate both hydrophobic and hydrophilic payloads for drug delivery applications. Despite their promise, polymersomes are limited in application due to their spherical shape, which is not readily taken up by cells, as demonstrated by solid nanoparticle scientists. This article describes a salt-based method for increasing the aspect ratios of spherical poly(ethylene glycol) (PEG)- based polymersomes. This method can elongate polymersomes and ultimately control their final shape by adding sodium chloride in post-formation dialysis. Salt concentration can be varied, as described in this method, based on the hydrophobicity of the block copolymer being used as the base for the polymersome and the target shape. Elongated nanoparticles have the potential to better target the endothelium in larger diameter blood vessels, like veins, where margination is observed. This protocol can expand therapeutic nanoparticle applications by utilizing elongation techniques in tandem with the dual-loading, long-circulating benefits of polymersomes.

Harm Reduction and Adaptations Among PWUD in Rural Oregon During COVID-19.

Coronavirus Disease 2019 (COVID-19) may influence HIV/HCV transmission risk behaviors in rural communities. We conducted semi-structured qualitative interviews with people who use drugs (PWUD) in five rural Oregon counties and asked about COVID-19 impact on substance use and harm reduction practices and their advice for improving public health responses. Participants (n = 36) reported using only methamphetamine (52.8%), only heroin (16.7%), or both (30.6%); 75% of participants reported recent injection. Three thematic categories emerged: SSP adaptations and accessibility, PWUD harm reduction practices, and policy suggestions. Participants noted the importance of SSPs to COVID-19 prevention and wellbeing, though some experienced increased barriers, leading to increased risky injection practices. Participants suggested need-based rather than one-for-one exchange, increasing syringe delivery services, encouraging secondary exchange by PWUD, and peers as trusted voices for information exchange. Rapid implementation of policy and practice changes are urgently required to improve SSP access, reinforce safer use, and prevent HIV/HCV and COVID-19 transmission.

Current Advances Toward the Encapsulation of Cas9.

Genetic diseases present formidable hurdles in maintaining a good quality of life for those suffering from these ailments. Often, patients look to inadequate treatments to manage symptoms, which can result in harmful effects on the body. Through genetic engineering, scientists utilize the clustered regularly short palindromic repeat (CRISPR)-associated protein, known as Cas9, to treat the root of the problem. The Cas9 protein is often codelivered with guide RNAs or in ribonucleoprotein complexes (RNP) to ensure targeted delivery of the genetic tool as well as to limit off-target effects. This paper provides an overview of the current advances made toward the encapsulation and delivery of Cas9 to desired locations in the body through encapsulating nanoparticles. Several factors must be considered when employing the Cas9 system to allow gene editing to occur. Material selection is crucial to protect the payload of the delivery vector. Current literature indicates that lipid- and polymer-based nanoparticles show the most potential as delivery vessels for Cas9. Lipid nanoparticles greatly outpace polymer-based nanoparticles in the clinic, despite the benefits that polymers may introduce. When developing translatable systems, there are factors that have not yet been considered that are relevant to Cas9 delivery that are highlighted in this Viewpoint. The proper functioning of Cas9 is dependent on maintaining a proper internal environment; however, there are gaps in the literature regarding these optimal conditions. Interactions between charges of the Cas9 protein, codelivered molecules, and delivery vehicles could impact the effectiveness of the gene editing taking place. While the internal charges of nanoparticles and their effects on Cas9 are presently undetermined, nanoparticles currently offer the ideal delivery method for the Cas9 protein due to their adequate size, modifiable external charge, and ability to be modified. Overall, a cationic lipid-/polymer-based nanoparticle system was found to have the most prospects in Cas9 delivery thus far. By understanding the successes of other systems, translatable, polymer-based delivery vehicles may be developed.

Combining Nanoparticle Shape Modulation and Polymersome Technology in Drug Delivery.

This paper highlights the potential benefits of using self-assembled polymeric nanoparticles of various shapes to enhance drug uptake. First, we highlight the growth and development of the polymersome, using a liposome as a blueprint for amphiphilic codelivery. Then, we focus on the advantages of nanoparticle elongation, drawing from the field of solid nanoparticles, as opposed to self-assembled vesicles which have not yet been extensively explored in shape-modulated drug delivery applications. Notably, regardless of the material used in the solid nanoparticle systems, more elongated shapes lead to greater cellular uptake, decreased interaction with the reticuloendothelial system macrophages, and increased circulation times. Finally, we highlight the methods currently being developed to modulate polymersome shape, thus providing a drug delivery system with the benefits derived from amphiphilicity and elongated structures. Current methods employed to modulate polymersome shape involve osmotic pressure gradients, solvent switching, and the use of cross-linking agents. Although these methods are successful in modulating polymersome shapes and the benefits of elongated nanoparticles in therapeutic targeting are clear, these methods have not yet been explored for applications in drug delivery.

The Impacts of COVID-19 on Mental Health, Substance Use, and Overdose Concerns of People Who Use Drugs in Rural Communities.

OBJECTIVES: The objective of this study was to investigate the impact of COVID-19 on the mental health, substance use, and overdose concerns among people who use drugs (PWUDs) in rural communities to explore reasons for changes and ways to mitigate COVID-19 impact in the future. METHODS: We conducted semi-structured in-depth interviews with PWUDs in 5 rural Oregon counties with high overdose rates. Participants were identified through participant-driven sampling along with flyer and text advertising (n = 36). Research staff conducted audio-recorded in-depth interviews via telephone, assessing COVID-19 effects on substance use, mental health, and overdose risk. Transcribed interviewers were coded for themes using a semantic approach. RESULTS: Participants reported various mental health symptoms and experiences due to COVID-19, including increased feelings of boredom, loneliness, and depression; increased worry and stress; and increased suicidal ideation. Participants described varying impacts of COVID-19 on substance use. Overall, participants who used only methamphetamine reported decreased use and people who used only heroin or heroin with methamphetamine reported increased use. Most participants reported that they were not concerned about overdose and that COVID-19 did not impact their concerns about overdose, despite increases in risky use and suicidal ideations. CONCLUSIONS: As rural communities respond to the evolving impacts of COVID-19, there is increasing need to identify strategies to address PWUD's mental, physical, and social health needs during COVID-19.