No abstract

Serotonergic innervation of the spinal cord in mammals has multiple roles in the control of motor, sensory and visceral functions. In rats, functional consequences of spinal cord injury at thoracic level can be improved by a substitutive transplantation of serotonin (5-HT) neurons or regeneration under the trophic influence of grafted stem cells. Translation to either pharmacological and/or cellular therapies in humans requires the mapping of the spinal cord 5-HT innervation and its receptors to determine their involvement in specific functions. Here, we have performed a preliminary mapping of serotonergic processes and serotonin-lA (5-HT1A) receptors in thoracic and lumbar segments of the human spinal cord. As in rodents and non-human primates, 5-HT profiles in human spinal cord are present in the ventral horn, surrounding motoneurons, and also contact their presumptive dendrites at lumbar level. 5-HT1A receptors are present in the same area, but are more densely expressed at lumbar level. 5-HT profiles are also present in the intermediolateral region, where 5-HT1A receptors are absent. Finally, we observed numerous serotonergic profiles in the superficial part (equivalent of Rexed lamina II) of the dorsal horn, which also displayed high levels of 5-HT1A receptors. These findings pave the way for local specific therapies involving cellular and/or pharmacological tools targeting the serotonergic system.

Chronic subdural hematoma (CSDH) is a common condition necessitating surgery; however, recurrence occurs in 15-25% of cases despite surgical management. The HEMACORT trial was a prospective randomized, double-blind, placebo-controlled, multi-centric study (NCT01380028). The aim of this trial was to determine the effect of corticosteroids as an adjuvant treatment to surgery on CSDH recurrence at 6 months. After surgery, participants were assigned by block-randomization to receive either placebo or oral prednisone at a dose of 1 mg/kg/day followed by weekly stepwise tapering in steps of 10 mg/day. The primary outcome was CSDH recurrence, defined by the need for reoperation and/or radiological progression of CSDH. Secondary outcomes were one-year death, radiological changes, safety, neurological status, and quality of life. The trial was discontinued at midpoint of expected inclusions: 78 participants received prednisone and 77 received placebo controls. In an intention-to-treat analysis, CSDH clinicoradiological recurrence was not different between prednisone and placebo groups (21.8% vs. 35.1%, respectively; hazard ratio 0.56; 95% confidence interval 0.30-1.02; p = 0.06), although post hoc analyses concluded to statistical significance ( p = 0.02). Earlier radiological resolution was observed after prednisone administration, but reoperation rates (reaching 5.8% overall) and functional outcomes were not different at 6 months. Among adverse events, sleep disorders occurred more often in the prednisone group (26.1% vs. 9.1%, p = 0.02). The HEMACORT trial data suggest that prednisone, as an adjuvant treatment to surgery, may reduce early radiological recurrence of CSDH, although clinical benefits are unclear. In view of these findings, the authors suggest that shorter treatment duration should be assessed for safety and efficacy in future trials.