Funded Projects

The University of California, San Francisco, as part of the Back Pain Consortium (BACPAC) Research Program, has established a Core Center for Patient-centric Mechanistic Phenotyping in Chronic Low Back Pain (REACH). The main goal of REACH is to define different subtypes (phenotypes) of chronic low back pain as well as to identify underlying pain mechanisms that can lead to effective, personalized treatments for patients across all population subgroups. To achieve this goal, REACH is, or will be, participating in several clinical trials, and it is imperative that the patients participating in these trials reflect the diversity of the U.S. population. Therefore, this project seeks to adapt methods that have successfully improved minority participation in other settings as well as to develop and deploy digital strategies that can promote recruitment and engagement of patients from marginalized populations.

Chronic overlapping pain conditions represent up to half of all chronic pain cases and can be more debilitating than other forms of chronic pain. These conditions include but are not limited to the following: temporomandibular disorders, fibromyalgia, irritable bowel syndrome, vulvodynia, interstitial cystitis/painful bladder syndrome, painful endometriosis, chronic tension type headache, migraine headache, chronic low back pain, and chronic fatigue syndrome. Common neurobiological mechanisms have been suspected to account for the overlap between these conditions, but until recently it has been difficult to efficiently classify each condition within individual patients. A digital classification tool for clinicians has been developed for this purpose, but access to the tool remains limited. Here we propose converting this chronic overlapping pain conditions classification tool into a common web-based application format.

There are numerous non-pharmacological interventions for chronic low back pain, yet no treatment is invariably effective for all. Understanding patient characteristics that predict differential responses to these non-pharmacological interventions will allow for tailored treatments to maximize positive patient impact. This supplement supports a training experience for an individual in clinical pain research, including exploring differential response to psychotherapeutic interventions. The aim of the project is to provide an extensive systematic literature review examining baseline phenotypic factors that predict differential responsiveness to the some of the most commonly used psychotherapeutic interventions for chronic low back pain.

Identifying optimal chronic low back pain treatments on a patient-specific basis is an important and unresolved challenge. Tailoring interventions according to patient movement characteristics is one option. This research is characterizing patients based on spinal motion during functional tasks and daily activities and will use artificial intelligence to objectively characterize motions of the spine during both clinical assessments and day-to-day life. During clinical assessments, participants will be asked to perform functional tasks while wearing motion sensors. Data collected from the sensors will be used to identify tasks of interest, such as activities of daily living and aberrant/painful motions. An artificial intelligence approach will then interpret data collected continuously during assessment in patients’ homes over a 7-day testing period. Ultimately, this data could be used to help clinicians tailor treatments that are responsive to a patient’s real-world functional impairments.

Cesarean deliveries are the most commonly performed surgical procedure in the United States. Opioids are almost universally used for post-cesarean analgesia management. Studies suggest that most women are prescribed more tablets at discharge than needed. These often go unused, providing an important reservoir contributing to the opioid crisis. Physicians struggle to prescribe and dose postoperative opioids appropriately while tackling the real needs of acute pain from surgery. Without literature to guide obstetric providers on appropriate amounts of opioids to prescribe upon discharge, actual prescription amounts nationally vary widely by up to 65 tablets. To improve post-cesarean opioid prescribing practices without compromising pain management, the study will test an individualized, patient-empowered approach for pain management and opioid prescription quantity. This is a noninferiority randomized trial of 5,500 women with a cesarean delivery who will be randomized prior to discharge.

Medications have proven to be effective for treating opioid use disorder (OUD). Increasing accessibility to buprenorphine provides an opportunity for many with OUD to benefit from its proven effectiveness. Adherence to medication-based treatments however is low, in part because of the stigma associated with use of this and other effective drugs and as such, leads to inadequate treatment and poor outcomes. This study aims to understand the effects of stigma on patient engagement, retention, and outcomes of buprenorphine treatment. Knowledge drawn from the HIV Stigma Theory and tools developed to reduce HIV associated stigma will be used to assess OUD stigma and to develop interventions to reduce it in the context of buprenorphine treatment. The study findings may provide resources to address stigma and thus maximize treatment adherence among those affected by OUD.

The primary objective of this project is to de-implement the use of opioid analgesics for the management of postoperative pain following dental extractions and to implement effective alternative pain management. We propose a cluster-randomized trial designin which dental practitioners are randomly assigned to one of three conditions: 1) standard practice as a control condition; 2) a clinical decision support (CDS) tool that will extract patient history and interface with the state prescription drug monitoring program to provide personalized recommendations for analgesic prescribing and offer language for discussing non-opioid pain management; 3) an enhanced version of the CDS (CDS-E) that will also include information regarding optimal, evidence-based non-opioid pain management delivered to the patient both before and following the dental extraction visit. We will examine opioid and non-opioid prescribing data from the electronic health record across study arms as well as other provider- and patient-focused outcomes using mixed methods.

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. 

Opioids and other addictive substances have powerful rewarding properties that drive the development of addiction. They also have aversive properties that motivate their avoidance and protect against addiction. This project will explore the role of Type 2 Taste Receptor proteins (Tas2Rs or T2Rs) in regulating the aversive properties of opioids, potentially establishing an entirely new class of receptors that can be targeted for the development of novel addiction therapeutics.

African American adults are less likely to receive analgesics, particularly opioids. Research in the pediatric surgical population is limited, but the pattern of disparate use of opioids appears consistent with adults. Furthermore, adolescent access to prescribed opioids has increased, both through physician prescribing and misuse of medications prescribed to family members or friends. This study will explore the interrelated impacts of policy, clinical need, and sociodemographic factors by combining Medicaid claims and electronic health record data with findings from a statewide opioid policy inventory. We will focus on discharge prescribing of opioids in three high-volume pediatric surgical procedures: tonsillectomy/adenoidectomy, supracondylar fracture, and appendectomy. We aim to 1) determine the extent of racial disparities in postoperative discharge opioid prescribing since the 2011 onset of enhanced opioid prescription reduction activities and 2) develop an expanded model to assess the linkage between differential opioid use for pediatric postoperative pain and opioid use-related outcomes.

Using neural tissues from pain patients, this project will investigate mechanisms of neuronal and/or immune dysfunction driving chronic pain. The researchers will use spatial transcriptomics on human dorsal root ganglion (DRG) and spinal cord tissues to examine the cellular expression profile for these targets using the 10X Genomics Visium technology. The use of tissues from control surgical patients and organ donors as well as surgical patients with neuropathic pain will enable validation of expression of these targets in human tissue as well as indication of their potential involvement in neuropathic pain. This collaborative effort will use DRGs removed from pain-phenotyped patients during neurological surgery, as well as lumbar DRGs and spinal cord from organ donors. This study will map the spatial transcriptomes at approximately single cell resolution in the human DRG and spinal cord.

Persistent pain states arising from inflammatory conditions, such as in arthritis, diabetes, HIV, and chemotherapy, exhibit a common feature in the release of damage-associated molecular pattern molecules, which can activate toll-like receptor-4 (TLR4). Previous studies suggest that TLR4 is critical in mediating the transition from acute to persistent pain. TLR4 as well as other inflammatory receptors localize to lipid raft microdomains on the plasma membrane. We have found that the secreted apoA-I binding protein (AIBP) accelerates cholesterol removal, disrupts lipid rafts, prevents TLR4 dimerization, and inhibits microglia inflammatory responses. We propose that AIBP targets cholesterol removal to lipid rafts harboring activated TLR4. The aims of this proposal are to: 1) determine whether AIBP targets lipid rafts harboring activated TLR4; 2) test whether AIBP reduces glial activation and neuroinflammation in mouse models of neuropathic pain; and 3) identify the origin and function of endogenous AIBP in the spinal cord.

Spinal cord injury (SCI) impairs sensory transmission and leads to chronic, debilitating neuropathic pain. While our understanding of the development of chronic pain has improved, the available therapeutics provide limited relief. We will examine the peripheral immune and inflammatory response. Secondary inflammation in response to SCI is a series of temporally ordered events: an acute, transient upregulation of chemokines, followed by the recruitment of monocytes/macrophages and generation of an inflammatory environment at the lesion site in the spinal cord, but also surrounding primary nociceptors in the dorsal root ganglia (DRG). These events precede neuropathic pain development. Previous work indicates that after SCI, macrophage presence in the DRG correlates with neuropathic pain. We propose to study: 1) whether the phenotype of macrophages that infiltrate the DRG is different than those that persist chronically after SCI and 2) how manipulation of macrophage phenotype affects nociceptor activity and pain development.