Sphingosine-1-Phosphate in Ovarian Hyperstimulation Syndrome: Biomarker Promise and Therapeutic Peril

To the Editor,
Ovarian hyperstimulation syndrome (OHSS) is a serious, potentially life-threatening iatrogenic complication of excessive ovarian response to stimulation during fertility treatments like in vitro fertilization (IVF), which is a part of assisted reproductive technology (ART). It is often triggered by human chorionic gonadotropin (hCG) when used to induce oocyte maturation. Due to its prolonged luteotropic effect compared to LH, hCG induces vasodilation, increases vascular permeability, and causes fluid shift into the third space, leading to ascites, pericardial and pleural effusions, and generalized edema. Severe cases may result in complications like adult respiratory distress syndrome, thromboembolism, and acute renal failure. Clinically, OHSS presents with enlarged cystic ovaries, abdominal distention, and pain (1).
OHSS is a serious complication with unclear pathophysiology. Lipids play important roles in cellular function and various diseases; hence, the alterations of lipids were investigated by lipidomic analysis using follicular fluid samples obtained from OHSS patients, showing a significant reduction in some classes of lipids, including LPC, dMePE, LdMePE, PI, PE, PC, TG and sphingomyelin (SM) and elevation of ChE in the OHSS group. These differential lipids might serve as potential biomarkers. Notably, sphingosine 1-phosphate (S1P) is a bioactive lipid mediator produced from sphingomyelin. S1P is found abundantly in blood and regulates vascular permeability, cell recruitment, and clotting during inflammatory processes. This role of S1P is achieved through a signaling pathway, which is mediated through S1PR1, a family of G protein-coupled receptors. Hence, S1P emerges as a promising biomarker and therapeutic target (2). Future randomized controlled studies should focus on refining the S1P role as a predictive marker for OHSS.
Studies suggest that women with OHSS have lower sphingosine-1-phosphate (S1P) levels in their follicular fluid compared to those without risk. This drop in S1P could act as an early warning sign, allowing timely intervention.