Pain
-
There are few studies that have looked at the occurrence of co-morbid conditions amongst patients with back problems. This study assesses the association between of a range of co-morbidities and the labour force participation rates of 45- to 64-year-old Australians with back problems. Logistic regression models were applied to the 2003 Survey of Disability, Ageing and Carers (SDAC) data to look at the relationship between chronic back problems, labour force participation and comorbidities. ⋯ For example, an individual with back problems and heart disease is more than 10 times more likely to be out of the labour force than those with back problems alone (OR=10.90, 95% CI=2.91-40.79, P=.0004). Amongst conditions that have a significant impact on labour force participation rates, back problems and multiple co-morbidities are significantly more likely to cause persons with these conditions to be out of the labour force than those with back problems alone or those with no chronic health condition. It is important to consider which co-morbidities an individual has when assessing the impact of back problems on labour force participation, as co-morbid conditions vary in their association with labour force participation.
-
Serotonin (5HT) is a pronociceptive mediator in the periphery, and evidence implicates involvement in trigeminal pain processing. However, the mechanism(s) by which 5HT modulates trigeminal nociceptors remains unclear. Trigeminal pain can be evoked by the transient receptor potential V1 channel (TRPV1), which is expressed by nociceptive trigeminal neurons and induces release of proinflammatory calcitonin gene-related peptide (CGRP). ⋯ We report that 5HT induced a significant increase in capsaicin-evoked CGRP release, and that this enhancement was observed only in female dental pulp, with no effect of 5HT on male dental pulp. The greatest amount of CGRP release occurred in dental pulp from women in the luteal phase of the menstrual cycle. These results indicate that 5HT enhances capsaicin-evoked CGRP release from human trigeminal nociceptors in a sexually dimorphic manner providing a mechanistic basis for prevalence of trigeminal pain disorders in women.
-
Although depressive symptoms are common among those living with back pain, there is limited information on the relationship between postsurgical pain reduction and changes in depressive symptoms. The objective of this prospective cohort study was to examine the change in pain and depressive symptoms and to characterize the relationship between pain and depressive symptoms after lumbar spine surgery. We assessed 260 individuals undergoing lumbar spine surgery preoperatively and postoperatively (3 and 6 months) using a pain intensity numeric rating scale and the Patient Health Questionnaire depression scale. ⋯ However, at 6 months, individuals who experienced a reduction in pain (63%) were nearly twice as likely to experience a reduction in depressive symptoms (odds ratio 1.93, 95% CI 1.15 to 3.25) as those who experienced no change or an increase in pain (31%). We found that most individuals experienced clinically important reductions in pain after surgery. We concluded that those whose pain level was reduced at 6 months were more likely to experience a reduction in depressive symptoms.
-
Recently, specific oxidized linoleic acid metabolites (OLAMs) have been identified as transient receptor potential vanilloid 1 (TRPV1) channel agonists that contribute to inflammatory and heat hyperalgesia mechanisms, yet the specific mechanism responsible for OLAM synthesis in sensory neurons is unknown. Here, we use molecular, anatomical, calcium imaging, and perforated patch electrophysiology methods to demonstrate the specific involvement of cytochrome P450 enzymes (CYPs) in the oxidation of linoleic acid leading to neuronal activation and show that this is enhanced under inflammatory conditions. Additional studies evaluated CYP expressions in the native rat trigeminal ganglia (TG) tissue and cultures as well as changes in their expression pattern following the induction of peripheral inflammation. ⋯ In situ hybridization studies demonstrated broad expression pattern of CYP3A23/3A1 and CYP2J4 within TG neurons. Anatomical studies characterized the expression of CYP3A1 and the CYP2J families within TG sensory neurons, including those with TRPV1, with about half of all TRPV1-positive neurons showing more prominent CYP3A1 and CYP2J expression. Together, these findings show that CYP enzymes play a primary role in mediating linoleic acid-evoked activation of sensory neurons and furthermore, implicate the involvement of specific CYPs as contributing to the formation of OLAMs that act as TRPV1 agonists within this subpopulation of nociceptors.
-
A recent cross-sectional study of National Guard troops found that pain and pain catastrophizing were prevalent and highly correlated with posttraumatic stress disorder (PTSD). At issue in the present study was whether pain and catastrophizing before military deployment could account for individual differences in PTSD symptoms after deployment. An anonymous survey was administered to a population sample of New Jersey National Guard troops before they were sent overseas and again when they returned home (1 year later). ⋯ Consistent with previous research, a cross-sectional analysis revealed that postdeployment pain and catastrophizing successfully accounted for unique variance in postdeployment PTSD. The failure of longitudinal predictors in the present study, therefore, cannot be attributed to insensitive screening instruments. These findings offer little or no support for the hypothesis that predeployment pain and catastrophizing can account for individual differences in PTSD after exposure to combat trauma.