Microglial TNFR2 signaling regulates the inflammatory response after CNS injury in a sex-specific fashion

Microglia, the resident immune cells of the central nervous system (CNS), play a major role in damage progression and tissue remodeling after acute CNS injury, including ischemic stroke (IS) and spinal cord injury (SCI). Understanding the molecular mechanisms regulating microglial responses to injury may thus reveal novel therapeutic targets to promote CNS repair. Here, we investigated the role of microglial tumor necrosis factor receptor 2 (TNFR2), a transmembrane receptor previously associated with pro-survival and neuroprotective responses, in shaping the neuroinflammatory environment after CNS injury. By inducing experimental IS and SCI in Cx3cr1CreER:Tnfrsf1bfl/fl mice, selectively lacking TNFR2 in microglia, and corresponding Tnfrsf1bfl/fl littermate controls, we found that ablation of microglial TNFR2 significantly reduces lesion size and pro-inflammatory cytokine levels, and favors infiltration of leukocytes after injury. Interestingly, these effects were paralleled by opposite sex-specific modifications of microglial reactivity, which was found to be limited in female TNFR2-ablated mice compared to controls, whereas it was enhanced in males. In addition, we show that TNFR2 protein levels in the cerebrospinal fluid (CSF) of human subjects affected by IS and SCI, as well as healthy donors, significantly correlate with disease stage and severity, representing a valuable tool to monitor the inflammatory response after acute CNS injury. Hence, these results advance our understanding of the mechanisms regulating microglia reactivity after acute CNS injury, aiding the development of sex- and microglia-specific, personalized neuroregenerative strategies.

Cryoneurolysis for the management of chronic pain in patients with knee osteoarthritis; a double-blinded randomized controlled sham trial

Objective

Pain is the principal symptom in knee osteoarthritis (OA). Current non-operative treatment options have only moderate effects and often patients experience persistent pain or side-effects. Novel advances in the field of cryoneurolysis applies low temperatures to disrupt nerve signaling at the painful area, providing pain relief. The primary aim of this randomized controlled trial (RCT) is to investigate if cryoneurolysis is superior to sham at decreasing pain intensity 2 weeks after the intervention in patients with knee OA. Secondary aims are to explore effects on pain, quality of life and functional performance over 24 months.

Methods

This two-arm, parallel-group RCT, approved by the Regional Ethics Committee, will randomly allocate patients (n = 94) to a cryoneurolysis intervention group + standardized education and exercise (CRYO) or a sham group + standardized education and exercise (SHAM) (1:1 ratio). Both groups will be assessed at baseline, 2 weeks post intervention, post education and exercise and at 6, 12 and 24 months after cryoneurolysis. The primary outcome is the NRS knee pain intensity score assessed 2 weeks post the intervention. Secondary outcome measures include functional performance (chair-stand test, 40 m walk, stair test and maximum voluntary contraction of the knee), patient reported outcomes (quality of life (EQ5D), Knee and osteoarthritis outcome scores (KOOS), among others), use of analgesics, and adverse events over 24 months.

Impact statement

Cryoneurolysis could potentially provide an effective, safe and non-pharmacological therapeutic option to treat pain in OA patients. The potential benefits include increased functional capacity and quality of life as a result of significant pain relief and improved benefits of physical exercise.

Trial registration

Clinicaltrials.gov, NCT03774121, registered 3 March 2018, http://www.clinicaltrials.gov