Pain
-
Age- and gender-matched reference values are essential for the clinical use of quantitative sensory testing (QST). To extend the standard test sites for QST-according to the German Research Network on Neuropathic Pain-to the trunk, we collected QST profiles on the back in 162 healthy subjects. Sensory profiles for standard test sites were within normal interlaboratory differences. ⋯ Compared to trunk reference data, patients with postherpetic neuralgia exhibited thermal and tactile deficits and dynamic mechanical allodynia, mostly without reduced mechanical pain thresholds. This pattern deviates from other types of neuropathic pain. QST reference data for the trunk will also be useful for patients with postthoracotomy pain or chronic back pain.
-
The blood-nerve barrier (BNB) is a selectively permeable barrier that creates an immunologically and biochemically privileged space for peripheral axons and supporting cells. The breakdown of the BNB allows access of blood-borne (hematogenous) cells and molecules to the endoneurium to engage in the local inflammatory cascade. This process was examined in a mouse model of trauma-associated neuropathic pain. ⋯ These results demonstrate that blood-borne molecules may play a role in the generation of neuropathic pain, suggesting that pain may be driven from infection or injury, at a distance from the nervous system. Furthermore, the breakdown of the BNB in neuropathic conditions was exploited to permit the entry of analgesic molecules that typically cannot pass the BNB, such as ProToxin-II, a BNB-impermeable Nav1.7 inhibitor. Therapeutics utilizing this mechanism could have selective access to injured nerves over healthy tissues.
-
Randomized Controlled Trial
A randomized, double blind, double dummy comparison of short- and long-acting dihydrocodeine in chronic non-malignant pain.
Guidelines for opioid treatment of chronic non-malignant pain recommend long-acting over short-acting opioid formulations. The evidence for this recommendation is weak. This study is a randomized, double-blind, double-dummy, 8-week comparison of long-acting dihydrocodeine tablets (DHC-Continus) with short-acting dihydrocodeine tablets in 60 patients with chronic non-malignant pain who were referred to a multidisciplinary pain clinic. ⋯ Breakthrough pain was experienced in both groups during the trial. Long-acting dihydrocodeine was not observed to be superior for any of the outcomes in this trial. The results of this study do not support current guidelines recommending long-acting opioids.
-
Randomized Controlled Trial
Safety, Tolerability, Pharmacokinetics, and Effects on Human Experimental Pain of the Selective Ionotropic Glutamate Receptor 5 (iGluR5) Antagonist LY545694 in Healthy Volunteers.
The objective of this study was to establish in healthy volunteers the maximally tolerated multiple dose (MTMD) of the ionotropic glutamate receptor 5 antagonist LY545694 (part A), and to investigate whether that dose had analgesic or antihyperalgesic effects in the brief thermal stimulation (BTS) pain model (Part B). Part A was a double-blind, placebo-controlled study in 3 groups of 10 healthy men. To simulate an extended-release formulation, study drug was administered orally over 6hours (12 equally divided aliquots at 30-minute intervals). ⋯ Neither gabapentin nor LY545694 reduced the painfulness of skin heating during BTS model induction. The most common treatment-emergent adverse event was dizziness. The results of this study suggest that LY545694 should be explored further as a potential treatment for chronic pain involving neuronal sensitization.
-
The role of psychosocial and physical factors in the development of musculoskeletal pain (MSP) has now been clearly demonstrated. However, it is unclear whether these factors contribute to specific regional MSP or to multisite pain. The main goal of this study was to assess the impact of work-related factors according to gender on the development of regional and multisite MSP. ⋯ Only for women, psychological factors were risk factors predictive of upper limb pain and in 3 or 4 painful anatomical sites. These results support the hypothesis that some physical and psychological work-related factors are predictive of regional or multisite MSP but differ according to gender. Gender differences and risk factors for work-related musculoskeletal pain should be also taken into account to more effectively target preventive measures.