Treatment of digoxin intoxication model by hybrid-kidney with hollowfibre module for clinical haemodialysis

Developments in extracorporeal therapy for the poisoned patient

The modern use of extracorporeal therapies to treat poisoning and drug overdoses dates back to the early 20th century and has evolved along with their use as treatment for acute kidney injury or as maintenance therapy in advanced kidney disease. As our understanding of drug pharmacokinetics and membrane materials has increased, the technologies of extracorporeal therapy and their applications have become more sophisticated. Despite that, there is little robust evidence to guide clinicians on the optimal use of extracorporeal therapy in treating poisoning beyond case reports and series. New efforts are underway to remedy that: the Extracorporeal Treatments in Poisoning Workgroup (EXTRIP) is an international effort on the part of nephrologists, pharmacists and toxicologists to review the available data and formulate evidence-based guidelines on how to use extracorporeal techniques to treat poisoning and improve patient outcomes. Meanwhile, new techniques and membranes are under development. This review will summarize those key scientific and technologic developments, the efforts to optimize their use and new directions in research.

Achievements and challenges in bioartificial kidney development

Bioartificial kidneys (BAKs) combine a conventional hemofilter in series with a bioreactor unit containing renal epithelial cells. The epithelial cells derived from the renal tubule should provide transport, metabolic, endocrinologic and immunomodulatory functions. Currently, primary human renal proximal tubule cells are most relevant for clinical applications. However, the use of human primary cells is associated with many obstacles, and the development of alternatives and an unlimited cell source is one of the most urgent challenges. BAKs have been applied in Phase I/II and Phase II clinical trials for the treatment of critically ill patients with acute renal failure. Significant effects on cytokine concentrations and long-term survival were observed. A subsequent Phase IIb clinical trial was discontinued after an interim analysis, and these results showed that further intense research on BAK-based therapies for acute renal failure was required. Development of BAK-based therapies for the treatment of patients suffering from end-stage renal disease is even more challenging, and related problems and research approaches are discussed herein, along with the development of mobile, portable, wearable and implantable devices.

Present status and perspectives of bioartificial kidneys

Currently, hemodialysis is not adequate as a renal replacement therapy because it provides intermittent treatment and does not provide the metabolic function of renal tubules. The next generation of artificial kidney should replace intermittent hemodialysis with continuous hemofiltration and provide the full metabolic function of renal tubules. The current decade has witnessed the development of bioartificial kidneys using artificial membranes and renal tubular epithelial cells. Active transport and metabolic functions were confirmed in the confluent monolayers of tubular cells on artificial membranes. Bioartificial kidneys have succeeded in improving the prognosis of patients with multiple organ dysfunction, presumably by lowering plasma cytokine levels in patients. For successful treatment of chronic renal failure using bioartificial kidneys, it is necessary to overcome some technical hurdles such as improving the antithrombogenic properties of the surface of artificial membranes and prolonging the function of renal tubule cells on an artificial membrane. Transfection of functional protein genes into renal tubule cells enables bioartificial tubule devices to increase their transport capacity and metabolic functions such as digoxin secretion and water transport. The development of wearable roller pumps is also essential for the clinical application of a continuous treatment system.