Patient phenotyping for molecular profiling of neck and low back pain - Study protocol

Chronic neck and low back pain are highly prevalent, leading causes of disability, and associated with long-term opioid use. The development of effective therapeutics is hampered by the limited understanding of the molecular mechanisms underlying these conditions. The Human Nociceptor and Spinal Cord Molecular Signature Center is a consortium within the NIH PRECISION Human Pain Network. The Center aims to fundamentally advance the understanding of the molecular neurobiology and neuroimmunology underlying human neck and low back pain, thereby enabling the discovery of therapeutic targets. We are pursuing this aim by applying bulk, single cell and spatial transcriptomics to tissues recovered from patients with neck and low back pain undergoing C1-2 and lumbar arthrodesis. The C2 dorsal root ganglion, facet joints, muscles, fascia, and intervertebral discs are harvested; control tissues are obtained from organ donors. A critical advantage of human research is the study of molecular neurobiological mechanisms in the context of the phenotypic complexity of chronic pain. The aim of this article is to summarize the rationale and methods used in our project to phenotype patients.

Phenotyping domains include pain-related characteristics such as pain intensity, duration, and location; physical function; psychosocial function; neuropathic components assessed by self-report and quantitative sensory testing; somatosensory functions such as mechanical pain sensitivity and temporal summation; and radiological findings.

We anticipate that comprehensive phenotyping will greatly facilitate the identification of phenotype-specific transcriptional signatures associated with chronic neck and low back pain, revealing new neurobiological and/or neuro-immunological mechanisms of painful diseases.