Funded Projects

Tens of thousands of people die each year from opioid overdose. Many of these people began taking opioids for pain. A critical treatment goal is to reduce the development of opioid dependence either by enhancing opioid analgesia so lower doses can be used or by blocking withdrawal symptoms. Current pharmacological treatments in these two categories, although effective, present serious limitations. The recent finding that reducing the signaling through mu-delta opioid heterodimers appears to enhance opioid antinociception and reduce dependence suggests that a blocker of mixed mu-delta receptors (MDOR antagonist) could be effective in reducing dependence by limiting opioid tolerance and preventing opioid withdrawal. This research group has developed a compound with that characteristic, called D24M, which preliminary studies have shown could reduce opioid dependence by enhancing opioid antinociception, reducing opioid tolerance, or directly inhibiting opioid withdrawal. They propose to extend this research by investigating whether it can reduce chronic pain in an animal model that mimics the clinical situation of pain patients who transition to dependence. If these studies are successful, they could lead to the development of an optimized drug ready for Investigational New Drug (IND) application and enable translational and clinical testing.

The ongoing opioid crisis has led to renewed concerns about the clinical prescription of addictive opioid analgesics. However, there are currently no suitable alternatives for treating severe or malignant pain. Studies of opioid signaling mechanisms in mice deficient in ?-arrestin have suggested that biased agonists displaying preferential activation of G-protein signaling over ?-arrestin signaling could offer a promising avenue for the development of opioid analgesics with a reduced adverse effects profile. However, there is no concluding evidence showing that such biased signaling can indeed be associated with reduced opioid side effects and, consequently, an improved safety profile. This research will address the need for preclinical data to rigorously evaluate this hypothesis with a program of in vivo studies to compare the effects of “balanced” opioids (morphine, oxycodone, and fentanyl) with that of the “biased” agonists PZM21 and two novel ligands provided by colleagues at the NIDA IRP in nonhuman primates. The results of these studies will provide critical information regarding the dependence liability of “biased” agonists that, in clinical practice, might be given on a repeated, or chronic, basis, potentially adding a powerful new tool for the safer management of severe or malignant pain.

The opioid epidemic continues unabated in the United States, and despite the rapid expansion of this crisis, the nature of the risk factors that contribute to opioid misuse remain poorly understood compared with other substances of abuse. The goal of this project is to examine cannabis use and cannabis identification measures as risk factors for opioid misuse while also developing and evaluating novel implicit measures of opioid associations as risk factors for opioid misuse among an at-risk sample of adolescents. Findings from the proposed research are intended to improve the prediction of opioid misuse among adolescents and to potentially identify novel targets for prevention and intervention strategies that aim to combat the opioid epidemic.

This study will (1) test pharmacologic and behavioral strategies to improve OUD pharmacotherapy treatment retention and to improve outcomes among patients who have been successfully stabilized on OUD medications and want to stop medication and (2) identify predictors of successful outcome and develop a stage model of relapse risk.

Neuropathic pain conditions are exceedingly difficult to treat, and novel non-opioid analgesics are desperately needed. Receptomic and unbiased transcriptomic approaches recently identified the orphan G-protein coupled receptor (oGPCR), GPR160, as a major oGPCR whose transcript is significantly increased in the dorsal horn of the spinal cord (DH-SC) ipsilateral to nerve injury, in a model of traumatic nerve-injury induced neuropathic pain caused by constriction of the sciatic nerve in rats (CCI). De-orphanization of GPR160 led to the identification of cocaine- and amphetamine-regulated transcript peptide (CARTp) as a ligand which activates pathways crucial to persistent pain sensitization. This project will test the hypothesis that CARTp/GPR160 signaling in the spinal cord is essential for the development and maintenance of neuropathic pain states. It will also validate GPR160 as a non-opioid receptor target for therapeutic intervention in neuropathic pain, and characterize GPR160 coupling and downstream molecular signaling pathways underlying chronic neuropathic pain.

Hesperos uses microphysiological systems in combination with functional readouts to establish systems capable of analysis of chemicals and drug candidates for toxicity and efficacy during pre-clinical testing, with initial emphasis on predictive toxicity. The team constructed physiological systems that represent cardiac, muscle and liver function, and demonstrated a multi-organ functional cardiac/liver module for toxicity studies as well as metabolic activity evaluations. In addition, the team demonstrated multi-organ toxicity in a 4-organ system composed of neuronal, cardiac, liver and muscle components. While much is known about the cells and neural circuitry regulating pain modulation there is limited knowledge regarding the precise mechanism by which peripheral and spinal level antinociceptive drugs function, and no available human-based model reproducing this part of the pain pathway. The ascending pain modulatory pathways provide a well characterized neural architecture for investigating pain regulatory physiology. In this project, the research team propose a human-on-a-chip neuron tri-culture system composed of nociceptive neurons, GABAergic interneurons and glutamatergic dorsal projection neurons (DPN) integrated with a MEMS construct. Using this model, investigators will interrogate pain signaling physiology at three levels, 1) at the site of origin by targeting nociceptive neurons with pain modulating compounds including noxious stimuli and inflammatory mediators, 2) at the inhibitory GABAergic interneuron, and 3) at the ascending spinal level by targeting glutamatergic DPNs. These circuits will be integrated utilizing expertise in patterning neurons as well as integration with BioMEMs devices. This system provides scientists with a better understanding of ascending pain pathway physiology and enable clinicians to consider alternative indications for treating pain at peripheral and spinal levels. 

According to SAMHSA’s 2017 National Survey on Drug Use and Health (NSDUH), 11.4 million persons in the U.S. report past-year opioid misuse; out of them, only 2.1 million individuals met criteria for an OUD. Very little is known about efficacious interventions for those who do not meet criteria for moderate/severe OUD (i.e., subthreshold OUD). The prevalence of subthreshold OUD in primary care settings is 5 percent to 10 percent, with higher rates (21 percent to 29 percent) among those receiving prescribed opioids. Although they are at high risk of developing moderate/severe OUD and/or dying from an overdose, little or no empirical evidence exists for pragmatic prevention interventions that can be adopted at integrated general medical settings. To study the efficacy of prevention interventions to arrest the progression from risky opioid use, researchers will test the efficacy of a STOP intervention in primary care settings. STOP adopts an early intervention approach, based on a collaborative care model to prevent progression to moderate/severe OUD, and consists of a practice-embedded nurse care manager who provides patient education and supports the primary care provider (PCP) in engaging, monitoring and guiding patients who have risky opioid use; brief advice delivered to patients by their PCP; and phone counseling of patients by behavioral health providers to motivate and support behavior change. Researchers will determine whether STOP reduces risky opioid use and examine the impact of STOP on progression to moderate/severe OUD, overdose risk behavior and overdose events in adults with risky use of illicit or prescription opioids.

Most of the 200k Americans who undergo thoracotomy each year receive opiates to reduce postoperative pain because clinicians have few non-addictive, cost-effective choices to control the severe pain patients often experience in the first two weeks after surgery. Managing pain post-thoracotomy is critical to enable patients to take deep breaths and remove (via coughing) lung secretions that otherwise significantly increase risk of pneumonia and collapsed lung, hospital re-admission and morbidity. The most severe pain associated with thoracotomy is transmitted along the intercostal nerves, but no long-term analgesic or nerve block device exists that can provide safe and effective long-term reduction of pain. A reversible, patient-controlled, non- addictive, intercostal nerve block device would reduce suffering due to thoracotomy, broken ribs and herpes zoster. In this Phase I project, the team will develop a minimally invasive thermal nerve block device that can control nerve conduction by gently warming and cooling a short nerve segment between room temperature and warm water temperature. This novel approach is based on the discovery that warm and cool temperature mechanisms of nerve block are different and additive, enabling moderate-temperature nerve block by cycling neural tissues slightly above and below body temperature. Reversible thermal nerve blocks represent a completely new approach to managing pain.  

Hospital inpatient stays due to opioid-related health problems are a reachable moment for increasing access to treatment with medications for opioid use disorder (MOUD). Hospitalized patients with opioid use disorder (OUD) are at particularly high risk for morbidity, mortality, and high medical costs in the U.S. This study will substantially inform the care management of OUD in hospitalized patients. The project includes a comparative effectiveness research trial and an implementation research trial, which will lead to models of broad dissemination for treatment approaches to this largely unaddressed population. They will examine whether (1) in hospitals with addiction medicine consultation services, hospital-initiated extended-release buprenorphine (XR-BUP), compared with other OUD medications, results in increased engagement in treatment with MOUD following hospital discharge and (2) training hospitals without such consultation services on best practices for initiating MOUD using consultation service hubs improves medication uptake in hospitals and increased MOUD treatment engagement following discharge.

Correctional settings have the potential to serve as key players in linking individuals with opioid use disorder (OUD) to treatment and health services upon release. Many individuals with OUD are being treated with medications, but these efforts will be ineffective if they fail to connect people to OUD treatment upon release. The Transitions Clinic Network (TCN) program provides enhanced primary care and OUD treatment for people recently released from incarceration. In TCN, formerly incarcerated community health workers are embedded within primary care teams and address social determinants of OUD, provide social support, help patients build trust in the health system, and advocate in interactions with the criminal justice system. This study will assess the effectiveness of the TCN: Post Incarceration Addiction Treatment, Healthcare, and Social Support (TCN PATHS) intervention versus referral to standard primary care on opioid treatment cascade outcomes and whether housing, food access, criminal justice contact, and social support mediate this association.

Opioids like morphine and hydrocodone are generally the most effective therapeutics for treatment of moderate to severe pain. However, their use is limited by serious side effects: tolerance, constipation, respiratory depression, physical dependence, and high addictive potential. Alternative pain relievers with the analgesic potency of conventional opioids, but devoid of narcotic side effects, are an immediate need. The goal of this project is to develop and commercialize an alternative to conventional opioid analgesics with reduced side effects and without the addictive properties common to mu-opioid agonists, targeting a new molecule in the central nervous system. This project will perform the necessary preliminary studies to prepare this new molecule for an investigational new drug application with the FDA.