Biofilters and biosensors

Sepsis is the leading cause of morbidity and mortality in intensive care units (ICU). Acute renal failure (ARF) is a common condition, affecting approximately 5% of all hospitalized patients and up to 20% of critically ill patients. The combination of ARF and sepsis is associated with 75% mortality. Hyperglycemia and an increase in plasma lactate concentration are markers of poor prognosis in patients with sepsis; they often precede the onset of multiple organ dysfunction and ARF. Direct online measurement by means of amperometric biosensors would allow the early detection of increasing levels of both glucose and lactate, as well as the possibility to maintain glucose within a well-defined range. Current standards of care in ARF require synthetic membranes that substitute the small solute clearance function of the renal glomerulus, but they do not replace the transport, metabolic and endocrine functions of the renal proximal tubule cells. The application of cell therapy to the successful process of hemofiltration may therefore improve the poor prognosis of patients with ARF in the ICU. An extracorporeal bioartificial kidney consisting of a conventional hemofilter connected to a renal tubule assist device has demonstrated both in animal models of ARF and in phase I/II clinical trials its ability to successfully replace the filtration, transport, metabolic, and endocrine functions of the kidney. To improve the outcome of septic patients with ARF, multidisciplinary interactions and cooperation between basic, clinical and industrial researchers are mandatory; the development of new artificial or biological devices may allow online monitoring of biological parameters and better treatment of septic syndrome and related systemic complications.