"Neuroinflammation": does it have a role in chronic pain? Evidence from human imaging

Investigating the potential of minocycline in reducing brain inflammation in chronic low back pain: a randomized, placebo-controlled mechanistic clinical trial

ABSTRACT

Our group has shown that translocator protein (TSPO) levels, a putative marker of neuroinflammation, are increased in the brain and spinal cord of patients with chronic low back pain (cLBP). Whether neuroinflammation might be a therapeutic target for this condition is unknown. In this phase II double-blind, placebo-controlled, randomized clinical trial, we sought to evaluate whether the tetracycline antibiotic minocycline, which is commonly used as a glial inhibitor in preclinical models, has an effect on brain TSPO levels in adults with cLBP. Participants randomly received 100-mg minocycline or placebo, once a day for 2 weeks. The primary outcome was the change (pretreatment vs posttreatment) in thalamic TSPO levels, measured using [11C]PBR28 positron emission tomography signal (standardized uptake value ratio) and analyzed with a mixed effect model. Secondary outcome measures included the change in Brief Pain Inventory, severity subscore. Among 60 enrolled participants, 48 completed the trial. Of these, 25 received minocycline (age [years], mean ± SD: 44.6 ± 16.9; 9 female), and 23 received placebo (49 ± 17.1; 9 female). The mean thalamic positron emission tomography standard uptake value ratio was very stable across visits in both groups, with no significant group-by-time interaction (P = 0.956). Similarly, both groups demonstrated a comparable decrease over time in Brief Pain Inventory severity scores (P = 0.018) and no significant group-by-time interaction (P = 0.329). Our results suggest that minocycline, at the tested regimen, may neither reduce brain TSPO levels nor have clinically meaningful effects on clinical pain in patients with cLBP.

Biochemical strategies for opioid-sparing pain management in the operating room

The opioid epidemic has highlighted the increasing need for alternative pain relievers in surgical settings. This review explores non-opioid approaches for managing pain in the ever-changing operating room. The review examines the molecular basis of pain perception, with a focus on receptor-targeted treatments that offer effectiveness without the risks associated with opioids. Despite the demonstrated benefits and improved side effect profiles, our literature analysis reveals the challenges that hinder the integration of innovative pain relievers. We explore the potential of neuroimmune modulators, peptide disruptors, and new neurotransmitter analogs in the quest for effective pain relief, paving the way for a future of anesthesia without opioids.

Fibromyalgia and Inflammation: Unrevealing the Connection

Fibromyalgia represents a chronic pain pathology characterized by severe musculoskeletal pain, fatigue, disturbances in sleep, and cognitive issues. Despite its presence, the underlying mechanisms of fibromyalgia remain inadequately understood; however, recent investigations have suggested that inflammation could play a fundamental role in the pathophysiology of this condition. Several studies highlight elevated concentrations of pro-inflammatory cytokines, dysregulation of immune responses, and neuroinflammation in fibromyalgia patients. Furthermore, chronic low-grade inflammation has been proposed as a potential catalyst for the sensitization of pain pathways, which exacerbates the symptoms of fibromyalgia. Understanding the role of inflammation in this disease might open new avenues for therapeutic interventions while providing a more profound insight into the complex nature of this debilitating disorder. Although progress has been made, further research is needed to uncover the complexities involved. This review investigates the intricate relationship between inflammation and fibromyalgia, analyzing the evidence that supports the involvement of both peripheral and central inflammatory processes in the onset and persistence of the disorder.