Sigma-1 receptor as an emerging target for painful diabetic neuropathy—a review

Neuropathic pain (NP) is a significant global health challenge, affecting an estimated 7–10% of the population. Painful diabetic neuropathy (PDN), a severe complication of diabetes, impacts approximately one in every three diabetic patients. With the rising global prevalence of diabetes, PDN is projected to become an increasingly urgent health concern. Current treatments for PDN often provide inadequate pain relief and are associated with adverse side effects, emphasizing the need for safe and effective therapeutic options. This review examines the limitations of existing pharmacological therapies for PDN and presents the sigma-1 receptor (S1R) as a promising therapeutic target. We explore the biological role of S1R, its implication in NP and PDN, its structural biology, and the expanding preclinical and clinical evidence supporting its potential. Furthermore, we present evidence for various S1R antagonists in addressing NP and PDN, with a particular focus on E-52862 and [18F]FTC-146. These compounds represent first-in-class ligands for therapeutic and diagnostic applications, respectively, marking significant advances in the development of S1R antagonists. This review underscores the potential of S1R antagonism as a strategy for developing more effective treatments for PDN, with the ability to significantly improve patient outcomes.