Hydrogen sulfide: a target to modulate oxidative stress and neuroplasticity for the treatment of pathological anxiety.

Introduction: Anxiety disorders result inhigh patient burden and utilization of healthcare resources. Evidence-based treatments for pathological anxiety include targeted psychotherapy and use of serotonin-augmenting agents. Limitations in access to cognitive behavioral therapy and potential disadvantages to the use of psychotropics make the need for novel approaches to therapeutics for pathological anxiety salient.Areas Covered: Neuroplasticity mechanisms, as well as managing oxidative stress and inflammatory cellular allostatic loads can decrease anxiety. The gasotransmitter hydrogen sulfide (H2S) can impact these mechanisms through a) maintaining intracellular reduced glutathione in the CNS to decrease oxidative stress; b) facilitating neuroplasticity in amygdalar regions via the 2B subunit of n-methyl-d-aspartate (NMDA) receptors, in conjunction with the cAMP messenger system and a CNS kinase, PKC-γ; and c) regulating intracellular Ca2+ homeostasis in neurons and glial cells, among others.Expert Opinion: Given the mounting evidence for the role of H2S in neuronal health and its potential to decrease pathological anxiety, the current challenge in H2S therapeutics remains finding an efficient delivery system of this gasotransmitter in a reliable, safe and nontoxic form to engage in clinical trials. Current efforts include H2S-delivering moieties attached to known drugs, natural sulfide-releasing compounds such as garlic, and the regulation of dysfunctional breathing through breathing retraining.