Recently, a team from PUMCH, led by Du Bin, Vice President and Director of the Department of Medical ICU (under preparation), Zhou Xiang, Director of Information Center and expert in critical care, and Ding Xin, Associate Chief Physician from the Department of Critical Care Medicine, published a “Perspective” article on membrane materials and sorbent design in blood purification in Chem (ranked as Tier 1, or among the top 5%, by the Chinese Academy of Sciences, IF=19.6), a sister journal to Cell. The article systematically reviews recent advances in extracorporeal blood purification technology for sepsis treatment, with particular emphasis on breakthrough innovations in membrane materials and sorbent design, offering comprehensive insights into treating this globally devastating condition.

Sepsis is a clinical syndrome of severe infection-induced multiorgan failure with persistently high mortality rates. The exaggerated inflammatory response—the so-called "cytokine storm"—triggered by sepsis leads to multiorgan failure and may cause patients to become immunoparalyzed, increasing the risk of secondary infections. Extracorporeal blood purification (ECBP) is an important adjunctive therapy for sepsis. This study examines recent innovations in membrane materials and sorbent technologies for ECBP, offering important theoretical insights to enhance treatment efficacy.

Regarding membrane materials, traditional continuous veno-venous hemofiltration membranes have relatively small pore sizes, limiting their ability to remove medium to large cytokines. Novel high-cutoff membranes, by expanding pore sizes, significantly enhance the clearance efficiency of inflammatory mediators while effectively improving patients' hemodynamic parameters, though they result in the loss of essential proteins such as albumin. Membranes with nonselective adsorption can adsorb low-molecular-weight proteins, and clinical studies have confirmed they can improve the prognosis of sepsis patients to some extent. Of particular interest is the three-layer membrane with selective adsorption—the AN69 oXiris membrane. Clinical research has confirmed that continuous veno-venous hemofiltration using this membrane can significantly reduce cytokine and endotoxin levels in septic shock patients, decrease 28-day mortality, and shorten ICU stay.

The research team identified three core sorbent categories targeting different therapeutic objectives. For pathogen clearance, polyethylene beads with end-point attached heparin can adsorb a broad spectrum of bacteria and viruses, showing the ability to alleviate bloodstream infections in both animal experiments and early human studies. For endotoxin clearance, polystyrene fiber sorbents selectively bind endotoxins through immobilized polymyxin B. According to Japanese research, they can reduce risk for hospital mortality by 3%-7%, though large randomized controlled trials did not demonstrate survival benefits associated with them. For cytokine clearance, styrene-divinylbenzene copolymer beads and styrene-divinylbenzene copolymer resin (HA-330/380) adsorbents can efficiently adsorb cytokines such as interleukin-6 and tumor necrosis factor-α. HA-330 combined with continuous blood purification therapy has been proven to improve clinical hemodynamic parameters.

Despite significant advances in ECBP, its clinical application faces several challenges. The study points out that many of these technologies lack robust evidence from large-scale, high-quality randomized controlled trials proving survival benefit; certain techniques carry notable adverse effects, including potential allergic reactions from plasma exchange therapy; and the medical community has not yet established appropriate biomarkers for determining optimal treatment timing and duration, thereby limiting the widespread adoption of ECBP in sepsis management.

In response, the team proposes three directions to further pursue: first, continuous optimization of membrane structure and sorbent materials to enhance selectivity and clearance efficiency while minimizing the loss of essential substances; second, exploration of "sequential ECBP therapy" strategies that adapt treatment protocols to different stages of sepsis progression, enabling multi-target precision clearance; and third, implementation of high-quality randomized controlled trials using indicators of organ function recovery as endpoints, such as mechanical ventilation duration and length of vasoactive medication administration to discover effective biomarkers and establish evidence-based foundations for personalized treatment approaches.

Written by Gan Dingzhu

Edited by Gan Dingzhu and Chen Xiao

Chief Editor Duan Wenli

Supervised by Wu Peixin