Project description:In this experiment we compare the effect of tibial nerve transection on gene expression within the dorsal root ganglion (DRG) of rats.
Project description:Neuropathic pain is caused by a lesion or disease of the somatosensory system, including peripheral fibres (Aβ, Aδ and C fibres) and central neurons, and affects 7-10% of the general population. Multiple causes of neuropathic pain have been described and its incidence is likely to increase owing to the ageing global population, increased incidence of diabetes mellitus and improved survival from cancer after chemotherapy. Indeed, imbalances between excitatory and inhibitory somatosensory signalling, alterations in ion channels and variability in the way that pain messages are modulated in the central nervous system all have been implicated in neuropathic pain. The burden of chronic neuropathic pain seems to be related to the complexity of neuropathic symptoms, poor outcomes and difficult treatment decisions. Importantly, quality of life is impaired in patients with neuropathic pain owing to increased drug prescriptions and visits to health care providers, as well as the morbidity from the pain itself and the inciting disease. Despite challenges, progress in the understanding of the pathophysiology of neuropathic pain is spurring the development of new diagnostic procedures and personalized interventions, which emphasize the need for a multidisciplinary approach to the management of neuropathic pain.
Project description:This program addresses the gene signature associated with DRG in the Chung rat model for neuropathic pain. The Chung neuropathic pain profiling data was analyzed by identifying genes that were up- and down-regulated at selected p value and fold change in DRG of the Sprague Dawley rats following spinal nerve ligation compared to the sham-operated controls.
Project description:ObjectivesThis is a prospective, blinded, case-control study of patients with chronic pain using body diagrams and colored markers to show the distribution and quality of pain and sensory symptoms (aching, burning, tingling, numbness, and sensitivity to touch) experienced in affected body parts.MethodsTwo pain physicians, blinded to patients' clinical diagnoses, independently reviewed and classified each colored pain drawing (CPD) for presence of neuropathic pain (NeuP) vs. non-neuropathic pain (NoP). A clinical diagnosis (gold standard) of NeuP was made in 151 of 213 (70.9%) enrolled patients.ResultsCPD assessment at "first glance" by both examiners resulted in correctly categorizing 137 (64.3% by examiner 1) and 156 (73.2% by examiner 2) CPDs. Next, classification of CPDs by both physicians, using predefined criteria of spatial distribution and quality of pain-sensory symptoms, improved concordance to 212 of 213 CPDs (Kappa = 0.99). The diagnostic ability to correctly identify NeuP and NoP by both examiners increased to 171 (80.2%) CPDs, with 80.1% sensitivity and 80.6% specificity (Kappa = 0.56 [95% confidence interval: 0.44-0.68]). The severity scores for pain and sensory symptoms (burning, tingling, numbness, and sensitivity to touch) on the Neuropathic Pain Questionnaire were significantly elevated in NeuP vs. NoP (P < 0.001).ConclusionsThis study demonstrates good performance characteristics of CPDs in identifying patients with NeuP through the use of a simple and easy-to-apply classification scheme. We suggest use of CPDs as a bedside screening tool and as a method for phenotypic profiling of patients by the quality and distribution of pain and sensory symptoms.
Project description:BackgroundDiagnosis and management of neuropathic pain (NP) in foot and ankle patients remain challenging. We investigated the plausibility of using Patient-Reported Outcomes Measurement Information System (PROMIS) Neuropathic Pain Quality (PQ-Neuro) as an initial screening tool to detect NP and track the treatment effects.MethodsPatients with heel pain were prospectively recruited and grouped to no-NP, mild-NP, and severe-NP based on the initial PROMIS PQ-Neuro t scores. Pain Interference (PI), Physical Function (PF), and Self-Efficacy (SE) scores were evaluated at baseline, 30-day, and 90-day follow-up. Other factors such as age, smoking, body mass index (BMI), low back/neck pain, anxiety/depression, and medications were analyzed. Linear mixed modeling was used to assess the main effects of time and NP on PROMIS t scores, comparing minimal clinically important difference (MCID).ResultsForty-eight patients with mean age of 52.4 years were recruited. Using the PROMIS PQ-Neuro as the assessment tool, 33 patients (69%) were detected to have NP at baseline-23 (48%) mild and 10 (21%) severe. BMI was the only independent factor associated with NP (P = .011). Higher baseline PQ-Neuro t score was significantly associated with higher follow-up PQ-Neuro (P < .001), PI (P = .005), and lower SE (P = .04) across time points. Patients with NP showed lower PF at baseline with significantly less improvement in PF (3 vs 9.9, P = .035) and did not meet MCID.ConclusionBaseline PROMIS PQ-Neuro ≥46 was significantly associated with worse PI and SE across all time points, with less clinically significant improvements in PF. Prevalence of NP in heel pain patients was high. The PROMIS PQ-Neuro may serve as a valuable tool for detection of NP and guiding clinical treatment decision pathways for heel pain patients.Level of evidenceLevel III, prospective cohort study.
Project description:Dry eye is a common, multifactorial disease currently diagnosed by a combination of symptoms and signs. Its epidemiology and clinical presentation have many similarities with neuropathic pain outside the eye. This review highlights the similarities between dry eye and neuropathic pain, focusing on clinical features, somatosensory function, and underlying pathophysiology. Implications of these similarities on the diagnosis and treatment of dry eye are discussed.
Project description:• Project description: Why only half of the idiopathic peripheral polyneuropathy (IPN) patients develop neuropathic pain is unknown. By conducting a proteomics analysis on IPN patients, we aimed to discover proteins and new pathways that are associated with neuropathic pain. We conducted unbiased mass-spectrometry proteomics analysis on blood plasma from 31 IPN patients with severe neuropathic pain and 29 IPN patients with no pain, to investigate protein biomarkers and protein-protein interactions associated with neuropathic pain. Univariate modeling was done with Linear mixed modeling (LMM) and corrected for multiple testing. Multivariate modelling was performed using elastic net analysis and validated with internal cross validation and bootstrapping.
Project description:Microglia have been implicated in the pathophysiology of neuropathic pain. Here, we sought to investigate whether cerebrospinal fluid (CSF) might be used as a proxy-measure of microglial activation in human participants. For this, we preformed fluorescent-activated cell sorting (FACS) of CSF immune cell populations derived from individuals who experienced pain with neuropathic features. We sorted CD4+, CD8+ T cells and monocytes and analyzed their transcriptome using RNA sequencing. We also performed Cellular Indexing of Transcriptomes and Epitopes (CITE)-seq to characterize the expression of all CSF immune cells in a patient with postherpetic neuralgia and in a patient with neuropathic pain after failed back surgery. Immune cell numbers and phenotypes were not obviously different between individuals regardless of the etiology of their pain. This was true when examining our own dataset, as well as when comparing it to previously published single-cell RNA sequencing data of human CSF. In all instances, CSF monocytes showed expression of myeloid cell markers commonly associated with microglia (P2RY12, TMEM119 and OLFML3), which will make it difficult to ascertain the origin of CSF proteins: do they derive directly from circulating CSF monocytes or could some originate in spinal cord microglia in the parenchyma? We conclude that it will not be straightforward to use CSF as a biomarker for microglial function in humans.