Pain
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Oral sucrose is administered routinely to reduce pain of minor procedures in premature infants and is recommended as standard care in international guidelines. No human or animal studies on effects of early repeated sucrose exposure on long-term brain development have been done in the context of pain. We evaluated the effects of repeated neonatal sucrose treatment before an intervention on long-term brain structure in mouse pups. ⋯ Cortical and subcortical gray matter was also affected by sucrose with smaller volumes of hippocampus and cerebellum (P < 0.0001). These significant changes in adult brain were found irrespective of the type of intervention in the neonatal period. This study provides the first evidence of long-term adverse effects of repetitive sucrose exposure and raises concerns for the use of this standard pain management practice during a period of rapid brain development in very preterm infants.
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The aim of this study was to examine a possible relationship between early puberty and chronic nonspecific pain in 13- to 18-year-old girls. All adolescents in Nord-Trøndelag County, Norway, were invited to participate in the Young-HUNT3 study (2006-2008). Of the invited girls, 81% answered the questionnaire and of these 3982 were 13 to 18 years of age. ⋯ A similar association was found between girls that perceived themselves as earlier physically matured than their peers and chronic nonspecific pain. Headache/migraine was the most common type of chronic nonspecific pain regardless of menarcheal age. In all reported locations, pain was more prevalent in the group with early menarche compared to normal or late menarche.
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Previous data suggest that persistent back pain may be associated with genetic variability. In this study, we assessed the correlation between 8 genetic polymorphisms (VDR, COL11, MMP1, MMP9, IL-1α, IL-1RN, OPRM1, COMT) and pain recovery in patients with low back pain (LBP) and lumbar radicular pain (LRP). In total, 296 patients with LBP or LRP were followed for 5 years. ⋯ In particular, the present study suggested that the OPRM1 rs179971 A>G in men was associated with better long-term pain recovery. In men, the OPRM1 rs1799971 explained 4.7% of the variance of pain intensity. We conclude that the MMP9 rs17576 and OPRM1 rs1799971 genotypes may affect 5-year recovery in patients with LBP and LRP.
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The human commensal microflora plays an essential role in modulating the immune response to control homeostasis. Staphylococcus epidermidis, a commensal bacterium most commonly associated with the skin exerts such effects locally, modulating local immune responses during inflammation and preventing superinfection by pathogens such as Staphylococcus aureus. Although the prostate is considered by many to be sterile, multiple investigations have shown that small numbers of gram-positive bacterial species such as S. epidermidis can be isolated from the expressed prostatic secretions of both healthy and diseased men. ⋯ Here, we report that intraurethral instillation of a specific S. epidermidis strain (designated NPI [non-pain inducing]), isolated from the expressed prostatic secretion of a healthy human male, into EAP-treated mice reduced the pelvic tactile allodynia responses and increased CD4+ve IL17A+ve T-cell numbers associated with EAP. Furthermore, a cell wall constituent of NPI, lipoteichoic acid, specifically recapitulates these effects and mediates increased expression of CTLA4-like ligands PDL1 and PDL2 on prostatic CD11b+ve antigen-presenting cells. These results identify a new potential therapeutic role for commensal S. epidermidis NPI lipoteichoic acid in the treatment of prostatitis-associated pain.
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Delayed-onset muscle soreness is typically observed after strenuous or unaccustomed eccentric exercise. Soon after recovery, blunted muscle soreness is observed on repeated eccentric exercise, a phenomenon known as repeated bout effect (RBE). Although regular physical activity decreases muscle hyperalgesia, likely because of increased production of the anti-inflammatory cytokine interleukin-10 (IL-10) in the skeletal muscle, whether IL-10 also contributes to the antinociceptive effect of RBE is unknown. ⋯ Although knockdown of IL-10R1 protein in nociceptors innervating the gastrocnemius muscle by intrathecal antisense oligodeoxynucleotide did not change nociceptive threshold in naive rats, it unveiled latent muscle hyperalgesia in rats submitted to eccentric exercise 12 days ago. Furthermore, antisense also prevented the reduction of muscle hyperalgesia observed after a second bout of eccentric exercise. These data indicate that recovery of nociceptive threshold after eccentric exercise and RBE-induced analgesia depend on a local effect of IL-10, acting on its canonical receptor in muscle nociceptors.