Contemporary scientific investigation is exploring effects of PPIs that are independent of their acid-suppressing function, potentially uncovering new therapeutic applications or complications.

• Anti-Tumor Potential: Studies are actively investigating a possible direct anti-cancer activity for some PPIs. This is based on observations that PPIs may interfere with specific tumor-cell pathways, potentially by targeting acidic compartments within cancer cells.

• Interference with Vascular Biology: Research suggests that certain PPIs may interact with biological mechanisms regulating vascular health. Specifically, some compounds may interfere with enzymes involved in the body's ability to create nitric oxide, which is important for blood vessel function, offering a possible explanation for some observed cardiovascular associations.

• Targeting Cysteine Proteases: New studies have demonstrated that certain PPIs can directly inhibit other enzymes, called cysteine proteases (like legumain and cathepsin B), which are involved in various cellular functions, including inflammation and immune response. This finding suggests a broader biological influence beyond the parietal cell.