Cardiovascular-Kidney-Metabolic (CKM) syndrome is a systemic disorder characterized by the intricate interplay between obesity, diabetes, cardiovascular disease, and chronic kidney disease. Due to its multi-organ complexity, the syndrome presents significant therapeutic challenges.

While Sodium-Glucose Cotransporter 2 (SGLT2) inhibitors, such as Empagliflozin (EMPA), have demonstrated cardio-renal benefits, their clinical efficacy is often hindered by poor renal specificity and systemic off-target exposure. Furthermore, high-dose administration can trigger adverse effects, including bone fractures, ketoacidosis, and urinary tract infections.

Additionally, oxidative stress plays a pivotal role in the pathogenesis of CKM, yet SGLT2 inhibitors cannot directly scavenge existing reactive oxygen species (ROS) in the kidneys. Therefore, improving the delivery efficiency of SGLT2 inhibitors while integrating antioxidant therapy has become a critical scientific challenge in managing CKM.

To address these issues, a research team led by Associate Professor Yang Zhe and Professor Tian Zhongmin from the School of Life Science and Technology at Xi'an Jiaotong University (XJTU) has developed a renal tubule-targeted, urea-responsive nanocarrier (T-PAAD NPs).

Building on their previous research into upper critical solution temperature (UCST) polymers, this platform achieves site-specific controlled release of EMPA within the renal proximal tubules. The nanocarrier utilizes the pathological rise of urea concentrations in the proximal tubules during kidney injury (from ~5 mM in healthy states to ~50 mM in terminal stages) as an endogenous trigger.

This urea-rich environment disrupts the intramolecular hydrogen-bonding network of the UCST polymer, causing the nanoparticles to disassemble and rapidly release the drug; at 50 mM urea, the cumulative release rate reaches ~93 percent within 24 hours. Concurrently, the incorporation of DATS (a sulfur-containing compound derived from garlic) into the carrier backbone confers excellent ROS-scavenging properties, synergistically alleviating oxidative stress in the kidneys.

In CKM mouse models, T-PAAD NPs/EMPA reshaped the balance of cardio-renal energy metabolism, reduced blood glucose and blood pressure, improved hemodynamic parameters, and mitigated atherosclerotic burden and hepatic steatosis. This comprehensive therapeutic effect was superior to free EMPA, demonstrating systemic potential for treating the multi-organ lesions associated with CKM syndrome.

This work marks the first application of a urea-responsive controlled-release strategy in renal nanomedicine. By constructing a multifunctional platform that integrates targeted delivery, smart release, and antioxidant therapy, this study provides a brand-new strategy for the comprehensive management of CKM syndrome and other systemic metabolic diseases.

These findings were published in the international multidisciplinary journal Nature Communications under the title A urea-activated nanocarrier for site-specific SGLT2 inhibition and metabolic rescue against cardiovascular-kidney-metabolic syndrome.