Nonspecific or axial-chronic low back pain is not attributed to specific pathology yet accounts for 80%- 90% of all chronic low back pain cases and is a major cause of disability affecting one in four adults with treatment costs and lost wages totaling $100-200 billion. Despite its prevalence, there is a knowledge gap around the underlying mechanisms driving susceptibility to this type of chronic pain. Gut microbial colonization plays a role in shaping host physiology directly through interactions with host tissues and indirectly through the production of metabolites, but the role of the microbiome in the etiology of axial-low back pain is unclear. Using a cross-sectional design, in this preliminary study, patients with axial-chronic low back pain and healthy controls completed the NIH minimal dataset for chronic low back pain from the PROMIS short form followed by collection of rectal swabs and 16S rRNA sequencing and determination of microbiome composition differences between controls and patients. Our findings suggest a distinct pattern of altered colonization in axial-chronic low back pain, characterized by a specific pattern of increased formate- and succinate- producing bacterial abundance along with reduced abundance of key taxa associated with butyrate, propionate, and acetate production. A review of the literature available on metabolite production from differentially abundant bacteria suggests a proinflammatory/ pronociceptive shift in microbial colonization. These preliminary findings identify a gut dysbiosis pattern that may contribute to chronic low back pain through pro-inflammatory and pronociceptive mechanisms; however, larger, longitudinal, and metabolically profiled studies are needed to confirm causality. Perspective Chronic low back pain is associated with gut dysbiosis characterized by reduced abundance of butyrate and/or propionate producing bacteria combined with increased succinate- and formate-producing bacterial colonization. These data suggest a proinflammatory/pronociceptive microbial signature that may contribute to development and/or maintenance of chronic low back pain.

Many chronic pain patients report co-occurring sleep disturbances, like insomnia, which have been linked to chronic pain development and exacerbation. Though these two complex conditions frequently co-occur, it is unclear whether these are distinct conditions or whether a common mechanism may underlie development of both. Using a bioinformatics approach, we identified potential pleiotropic genes associated with both phenotypes. As a first step, we developed a pipeline to prioritize genes implicated via single nucleotide variants (SNVs) associated with both insomnia and chronic pain phenotypes in genome-wide association studies (GWAS). This search resulted in 8 SNVs located in or between 11 genes. Using the Functional Mapping and Annotation database, FUMA v1.5.6, we identified 29 genes associated with our phenotypes of interest and then mapped these to their mouse orthologs using the DRSC integrative ortholog prediction tool (DIOPT v9.0) resulting in a final list of 26 mouse genes. Using previously published whole genome-sequencing data generated from multiple inbred mouse strains, we identified 86 variants within our prioritized mouse genes. Leveraging differential expression data between closely related mouse sub-strains to narrow this list to 5 genes, Mapt, Kansl1, Uqcc2, Grm4, and Dcc, implicated in insomnia and chronic pain in humans that contained 47 variants differing between sub-strains warranting further investigation. This pipeline facilitates the generation of novel hypotheses centered around common genetic mechanisms of risk for both insomnia and chronic pain. Follow-up studies examining how these genes interact together or independently as well as potential for these genes to encode pharmaceutical targets are warranted.

Metabolomics, the study of small-molecule metabolites within biological systems, has become a potent instrument for understanding cellular processes. Despite its profound insights into health, disease, and drug development, identifying the protein partners for metabolites, especially dietary phytochemicals, remains challenging. In the present study, we introduced an innovative in silico, structure-based target prediction approach to efficiently predict protein targets for metabolites. We analyzed 27 blood serum metabolites from nutrition intervention studies’ blueberry-rich diets, known for their health benefits, yet with elusive mechanisms of action. Our findings reveal that blueberry-derived metabolites predominantly interact with Carbonic Anhydrase (CA) family proteins, which are crucial in acid-base regulation, respiration, fluid balance, bone metabolism, neurotransmission, and specific aspects of cellular metabolism. Molecular docking showed that these metabolites bind to a common pocket on CA proteins, with binding energies ranging from −5.0 kcal/mol to −9.0 kcal/mol. Further molecular dynamics (MD) simulations confirmed the stable binding of metabolites near the Zn binding site, consistent with known compound interactions. These results highlight the potential health benefits of blueberry metabolites through interaction with CA proteins.

Visceral hypersensitivity (VH) is commonly cited as a driver of chronic abdominal pain in disorders of gut-brain interactions (DGBI) where persistent and/or recurrent abdominal pain is a primary symptom regardless of any alterations in bowel habits. Development of VH is influenced by genetic, environmental, and gut microbial colonization factors, yet specific mechanisms that generate VH are incompletely understood. Correspondingly, current pain treatments for DGBI, including irritable bowel syndrome (IBS), primarily focus on symptom management and severity rather than targeting the pathophysiological mechanisms underlying pain. We have begun to examine the role of genetic susceptibility and microbiome response dynamics in VH development using intracolonic zymosan (ZYM), which is a preclinical model of post-inflammatory IBS. Preliminary data reveals differential susceptibility between ZYM-induced VH in two closely related C57BL/6 sub strains; one from Taconic Biosciences (C57BL/6NTac) and the other from Jackson Laboratory (C57BL/6J). Using genomic comparisons, we have identified a VH candidate gene that encodes the arginine-vasopressin receptor 1A (Avpr1a/AVPR1A) protein. We have subsequently observed dynamic strain differences in the location and composition of the gut microbiome in response to ZYM corresponding to VH susceptibility. Further, we’ve identified colon-specific alterations in enteric neuron response properties that covary with gene expression and the pattern of microbial colonization corresponding to VH development. Through manipulation of the expression of Avpr1a and of the microbiome in the colon, we can develop novel tissue-specific pharmacological interventions designed to the target the mechanisms underlying chronic VH.

Estimates suggest that only 24.9% of infants born in 2019 were exclusively breastfed before 6 months of age, despite the known health benefits of exclusive breastfeeding. Breast and nipple pain is one of the primary determinants of exclusive breastfeeding. Environmental contributions to breastfeeding success have been reported extensively in the literature, but the contribution(s) of maternal genetics has yet to be discovered. The purpose of the study was to identify an association between pain and lactation-related gene variants with exclusive breastfeeding determinants. We selected 4 genes having single nucleotide polymorphisms (SNPs) with potential functional significance in breastfeeding and pain: prolactin receptor (PRLR), oxytocin receptor (OXTR), catechol-O-methyltransferase (COMT), and milk fat globule epidermal growth factor and factor V/VIII domain containing (MFGE8). We performed a cross-sectional secondary analysis of a longitudinal randomized controlled trial study, Promoting Self-Management of Breast and Nipple Pain with Biomarkers and Technology for Breastfeeding Women (NCT05262920). Breast and nipple pain, perceived insufficient milk, and breastfeeding self-efficacy were examined using total scale scores for the Brief Pain Inventory, Visual Analog Scale, H&H Lactation Scale, and the Breastfeeding Self-efficacy Scale-short form, respectively. Of the candidate genes examined, SNPs within COMT were significantly associated with breastfeeding-related outcomes. Specifically, COMT rs4633 and rs4680 minor allele carriers (T, A) reported higher breast and nipple pain intensity than women homozygous for the major allele (C, G). COMT is the most widely researched "pain gene" and has been linked to cold, postoperative, and postpartum pain. This study is the first to identify a contribution of COMT variants to breast and nipple pain and, as a result, to breastfeeding exclusivity. PERSPECTIVE: Two SNPs in the pain gene COMT are associated with breast and nipple pain. Clinically, a minor allele in COMT rs4633 and rs4680 may increase a woman's rating of moderate breast and nipple pain. TRIAL REGISTRATION: PROMPT was registered in ClinicalTrials.gov (protocol #NCT05262920).

Spinal cord injury (SCI) is associated with the development of treatment-resistant chronic pain that most commonly presents below the level of injury. Novel therapeutics are essential to reduce risk of chronic pain development and improve functional recovery. We and others have shown that SCI causes an increase in below-level nociceptor hyperactivity that is associated with the development and persistence of below-level pain. The mechanism responsible for this increase in below-level nociceptor activity is not well understood, but whole transcriptome RNA sequencing of the spinal cord and DRG has suggested that SCI increases expression and release proinflammatory cytokine, IL-1β, at the site of injury, while its expression of its receptor, IL-1R1, is increased in below-level DRG. To test our hypothesis that spinal release of IL-1β causes below-level nociceptor hyperactivity and pain via activation of IL-1R1, we quantified SCI-induced changes in IL-1b and IL-1R1 protein expression in the spinal cord, DRG, and hind paw glabrous skin, DRG over time, and whether treatment with IL-1β neutralizing antibody (nAb) attenuates IL-1R1 expression in female mice with moderate thoracic contusion injuries. Immunohistochemical (IHC) analysis showed that nAb treatment at the time of SCI reduces IL-1R1 expression in below-level DRG neurons. However, nAb treatment did not significantly reduce spontaneous pain as measured by facial grimace. Interestingly, conditional deletion of Il1r1 from sensory neurons reduced spontaneous pain in male, but not female, mice. Collectively, our data suggest attenuating afferent-specific IL-1β signaling reduces SCI pain in male mice. Funding: NIH grants R03 NS096454 (KMB), R21 NS104789 (KMB), the Rita Allen Foundation Award in Pain (KMB), The Craig H. Neilson Foundation (KMB, EEY, SNV), the KUMC Biomedical Research Training Program, and core support from the Kansas IDDRC P30 HD 000228, Administrative Supplement to P20 GM103418 (Awarded to EEY and KMB).

Background and aimsSpinal cord injury (SCI) affects roughly 300,000 Americans with 17,000 new cases added annually. In addition to paralysis, 60% of people with SCI develop neurogenic bowel (NB), a syndrome characterized by slow colonic transit, constipation, and chronic abdominal pain. The knowledge gap surrounding NB mechanisms after SCI means that interventions are primarily symptom-focused and largely ineffective. The goal of the present studies was to identify mechanism(s) that initiate and maintain NB after SCI as a critical first step in the development of evidence-based, novel therapeutic treatment options.MethodsFollowing spinal contusion injury at T9, we observed alterations in bowel structure and function reflecting key clinical features of NB. We then leveraged tissue-specific whole transcriptome analyses (RNAseq) and fecal 16S rRNA amplicon sequencing in combination with histological, molecular, and functional (Ca2+ imaging) approaches to identify potential mechanism(s) underlying the generation of the NB phenotype.ResultsIn agreement with prior reports focused on SCI-induced changes in the skin, we observed a rapid and persistent increase in expression of calcitonin gene-related peptide (CGRP) expression in the colon. This is suggestive of a neurogenic inflammation-like process engaged by antidromic activity of below-level primary afferents following SCI. CGRP has been shown to disrupt colon homeostasis and negatively affect peristalsis and colon function. As predicted, contusion SCI resulted in increased colonic transit time, expansion of lymphatic nodules, colonic structural and genomic damage, and disruption of the inner, sterile intestinal mucus layer corresponding to increased CGRP expression in the colon. Gut microbiome colonization significantly shifted over 28 days leading to the increase in Anaeroplasma, a pathogenic, gram-negative microbe. Moreover, colon specific vagal afferents and enteric neurons were hyperresponsive after SCI to different agonists including fecal supernatants.ConclusionsOur data suggest that SCI results in overexpression of colonic CGRP which could alter colon structure and function. Neurogenic inflammatory-like processes and gut microbiome dysbiosis can also sensitize vagal afferents, providing a mechanism for visceral pain despite the loss of normal sensation post-SCI. These data may shed light on novel therapeutic interventions targeting this process to prevent NB development in patients.

Objectives: Metabolomics explores complex relationships between small-molecule metabolites and biological systems, and has evolved into a potent tool for unraveling the intricacies of cellular processes. Even though it offers profound insights into complex relationships between metabolites and health, a crucial hurdle remains in identifying the associated protein companions that interact with these metabolites, especially in the vast, uncharted territory of dietary phytochemicals. In the present study, our main objective is to employ a structure-based target prediction workflow by introducing an innovative in-silico approach that systematically and efficiently predicts protein targets for metabolites. Methods: We develop a workflow to determine the protein targets for the dietary metabolites and utilize docking to predict the binding of these metabolites to the protein targets. Although this methodology encompasses a multi-faceted process, ranging from the analysis of untargeted and targeted metabolomics data to molecular modeling and exploration of interaction networks, our focus is directed towards a specific set of blood serum metabolites derived from nutrition intervention studies feeding diets rich in blueberries, which are known to have health benefits. In addition to engaging with multiple protein targets, the findings indicate that gut metabolites derived from blueberry consumption predominantly interact with carbonic anhydrase family proteins and play a crucial role in various physiological processes, including acid-base regulation, fluid balance, bone metabolism, neurotransmission, and specific aspects of cellular metabolism. Results: The molecular docking of these dietary metabolites with predicted carbonic anhydrase protein family as major protein targets and has revealed a common binding pocket, exhibiting binding energies comparable to those of experimentally validated compounds. Conclusions: This research sheds additional light on the molecular mechanisms underlying the health benefits of blueberries and provided a novel insights into precision nutrition strategies by integrating a structural and computational metabolomics workflow. Funding Sources: This work was supported in part through USDA-ARS project 6026-51000-012-000D, and Kansas IDeA Network of Biomedical Research Excellence (K-INBRE) P20GM103418.

Chronic abdominal pain in the absence of ongoing disease is the hallmark of disorders of gut-brain interaction (DGBIs), including irritable bowel syndrome (IBS). While the etiology of DGBIs remains poorly understood, there is evidence that both genetic and environmental factors play a role. In this study, we report the identification and validation of arginine-vasopressin receptor 1A (Avpr1a) as a novel candidate gene for visceral hypersensitivity (VH), a primary peripheral mechanism underlying abdominal pain in DGBI/IBS. Comparing 2 C57BL/6 (BL/6) substrains (C57BL/6NTac and C57BL/6J) revealed differential susceptibility to the development of chronic VH following intrarectal zymosan instillation, a validated preclinical model for postinflammatory IBS. Using whole-genome sequencing, we identified a single-nucleotide polymorphism differentiating the 2 strains in the 5' intergenic region upstream of Avpr1a, encoding the protein Avpr1a. We used behavioral, histological, and molecular approaches to identify distal colon-specific gene expression and neuronal hyperresponsiveness covarying with Avpr1a genotype and VH susceptibility. While the 2 BL/6 substrains did not differ across other gastrointestinal phenotypes (eg, fecal water retention), VH-susceptible BL/6NTac mice had higher colonic Avpr1a mRNA and protein expression. These results parallel findings that patients' colonic Avpr1a mRNA expression corresponded to higher pain ratings. Moreover, neurons of the enteric nervous system were hyperresponsive to the Avpr1a agonist arginine-vasopressin, suggesting a role for enteric neurons in the pathology underlying VH. Taken together, these findings implicate differential regulation of Avpr1a as a novel mechanism of VH susceptibility as well as a potential therapeutic target specific to VH. PERSPECTIVE: This article presents evidence of Avpr1a as a novel candidate gene for VH in a mouse model of IBS. Avpr1a genotype and/or tissue-specific expression represents a potential biomarker for chronic abdominal pain susceptibility.

Chronic abdominal pain in the absence of ongoing disease is the hallmark of disorders of gut- brain interaction (DGBIs), including irritable bowel syndrome (IBS). While the etiology of DGBIs remains poorly understood, there is evidence that both genetic and environmental factors play a role. In this study, we report the identification and validation of arginine-vasopressin receptor 1A ( Avpr1a ) as a novel candidate gene for visceral hypersensitivity (VH), a primary peripheral mechanism underlying abdominal pain in DGBI/IBS. Comparing 2 C57BL/6 (BL/6) substrains (C57BL/6NTac and C57BL/6J) revealed differential susceptibility to the development of chronic VH following intrarectal zymosan instillation, a validated preclinical model for postinflammatory IBS. Using whole-genome sequencing, we identified a single-nucleotide polymorphism differentiating the 2 strains in the 5 ' intergenic region upstream of Avpr1a, , encoding the protein Avpr1a. . We used behavioral, histological, and molecular approaches to identify distal colon-specific gene expression and neuronal hyperresponsiveness covarying with Avpr1a genotype and VH susceptibility. While the 2 BL/6 substrains did not differ across other gastrointestinal phenotypes (eg, fecal water retention), VH-susceptible BL/6NTac mice had higher colonic Avpr1a mRNA and protein expression. These results parallel findings that patients' colonic Avpr1a mRNA expression corresponded to higher pain ratings. Moreover, neurons of the enteric nervous system were hyperresponsive to the Avpr1a agonist arginine-vasopressin, suggesting a role for enteric neurons in the pathology underlying VH. Taken together, these findings implicate differential regulation of Avpr1a as a novel mechanism of VH susceptibility as well as a potential therapeutic target specific to VH. Perspective: This article presents evidence of Avpr1a as a novel candidate gene for VH in a mouse model of IBS. Avpr1a genotype and/or tissue-specific expression represents a potential biomarker for chronic abdominal pain susceptibility. (c) 2024 The Author(s). Published by Elsevier Inc. on behalf of United States Association for the Study of Pain, Inc This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Neurogenic bowel (NB) affects 60% of people with spinal cord injury (SCI) and is characterized by slow colonic transit, constipation, and chronic abdominal pain. NB rarely resolves and tends to worsen over time, making it a long-term challenge. The knowledge gap surrounding NB mechanisms after SCI means that interventions are primarily symptom-focused and largely ineffective. Identifying the mechanism(s) that initiate and maintain NB after SCI is critically important to the development of evidence-based, novel therapeutic options for NB after SCI. We employed tissue-specific, multi-omics approaches in a T8-10 mouse model of contusion SCI to characterize NB pathogenesis. Preliminary analyses indicate a rapid and persistent increase in expression of the inflammatory mediator, calcitonin gene-related peptide (CGRP), suggestive of neurogenic inflammation engaged by SCI. Intrarectal antagonism of CGRP activity significantly prevents NB-like phenotypes including colonic dysmotility, neoplastic lymphoid hyperplasias, and other structural defects of the colon. Interestingly, the effect of gut microbial dysbiosis including primary afferent hyperresponsiveness to fecal supernatants was also prevented by CGRP antagonism. This suggests that CGRP overexpression not only precedes microbiome dysbiosis but also that dysbiosis can be prevented by targeting CGRP at the time of injury. These data support the role for CGRP as a biological substrate for NB after SCI and a potential novel therapeutic target for the prevention of maladaptive colonic inflammation and gut dysbiosis in NB.

Treatment of carbapenemase-producing carbapenem-resistant Pseudomonas aeruginosa (CP-CRPA) infections is challenging because of antibiotic resistance. CP-CRPA infections are highly transmissible in health care settings because they can spread from person to person and from environmental sources such as sink drains and toilets. During September 2021-January 2022, an Idaho hospital (hospital A) isolated CP-CRPA from sputum of two patients who stayed in the same intensive care unit (ICU) room (room X), 4 months apart. Both isolates had active-on-imipenem metallo-beta-lactamase (IMP) carbapenemase gene type 84 (blaIMP-84) and were characterized as multilocus sequence type 235 (ST235). A health care-associated infections team from the Idaho Division of Public Health visited hospital A during March 21-22, 2022, to discuss the cluster investigation with hospital A staff members and to collect environmental samples. CP-CRPA ST235 with blaIMP- 84 was isolated from swab samples of one sink in room X, suggesting it was the likely environmental source of transmission. Recommended prevention and control measures included application of drain biofilm disinfectant, screening of future patients who stay in room X (e.g., the next 10 occupants) upon reopening, and continuing submission of carbapenemresistant P. aeruginosa (CRPA) isolates to public health laboratories. Repeat environmental sampling did not detect any CRPA. As of December 2022, no additional CP-CRPA isolates had been reported by hospital A. Collaboration between health care facilities and public health agencies, including testing of CRPA isolates for carbapenemase genes and implementation of sink hygiene interventions, was critical in the identification of and response to this CP-CRPA cluster in a health care setting.

group) and the effects were blocked by a pan-alpha1 ADR antagonist.These results suggest 1) tumor-induced sensory and sympathetic nerve injury may underly oral cancer pain, and 2) sensory and sympathetic ADR plasticity allows for NE released by SCG axons in the TG to act on alpha1-ADRs on nociceptors contributing to sympathetically-maintained pain.NIH NIDCR R01DE030892.

Chronic abdominal pain in the absence of ongoing disease is the hallmark of disorders of gut-brain interaction (DGBIs), including irritable bowel syndrome (IBS). While the etiology of DGBIs remains poorly understood, there is evidence that both genetic and environmental factors play a role. In this study, we report the identification and validation of Avpr1a as a novel candidate gene for visceral hypersensitivity (VH), a primary peripheral mechanism underlying abdominal pain in DGBI/IBS. Comparing two C57BL/6 (BL/6) substrains (C57BL/6NTac and C57BL/6J) revealed differential susceptibility to the development of chronic VH following intrarectal zymosan (ZYM) instillation, a validated preclinical model for post-inflammatory IBS. Using whole genome sequencing, we identified a SNP differentiating the two strains in the 5' intergenic region upstream of Avpr1a, encoding the protein arginine-vasopressin receptor 1A (AVPR1A). We used behavioral, histological, and molecular approaches to identify distal colon-specific gene expression differences and neuronal hyperresponsiveness covarying with Avpr1a genotype and VH susceptibility. While the two BL/6 substrains did not differ across other gastrointestinal (GI) phenotypes (e.g., GI motility), VH-susceptible BL/6NTac mice had higher colonic Avpr1a mRNA and protein expression. Moreover, neurons of the enteric nervous system were hyperresponsive to the AVPR1A agonist AVP, suggesting a role for enteric neurons in the pathology underlying VH. These results parallel our findings that patients' colonic Avpr1a mRNA expression was higher in patients with higher pain ratings. Taken together, these findings implicate differential regulation of Avpr1a as a novel mechanism of VH-susceptibility as well as a potential therapeutic target specific to VH.