Management of Acute Renal Dysfunction in Sepsis

The Supporting Role of Combined and Sequential Extracorporeal Blood Purification Therapies in COVID-19 Patients in Intensive Care Unit

Critical clinical forms of COVID-19 infection often include Acute Kidney Injury (AKI), requiring kidney replacement therapy (KRT) in up to 20% of patients, further worsening the outcome of the disease. No specific medical therapies are available for the treatment of COVID-19, while supportive care remains the standard treatment with the control of systemic inflammation playing a pivotal role, avoiding the disease progression and improving organ function. Extracorporeal blood purification (EBP) has been proposed for cytokines removal in sepsis and could be beneficial in COVID-19, preventing the cytokines release syndrome (CRS) and providing Extra-corporeal organ support (ECOS) in critical patients. Different EBP procedures for COVID-19 patients have been proposed including hemoperfusion (HP) on sorbent, continuous kidney replacement therapy (CRRT) with adsorbing capacity, or the use of high cut-off (HCO) membranes. Depending on the local experience, the multidisciplinary capabilities, the hardware, and the available devices, EBP can be combined sequentially or in parallel. The purpose of this paper is to illustrate how to perform EBPs, providing practical support to extracorporeal therapies in COVID-19 patients with AKI.

Extracorporeal renal replacement therapies in the treatment of sepsis: where are we?

Acute kidney injury (AKI) is common among the critically ill, affecting approximately 40% of patients. Sepsis is the cause of AKI in almost 50% of cases of intensive care patients, however, any evidence-based treatment for sepsis-associated AKI is lacking. Furthermore, the underlying pathophysiology of septic AKI is inadequately understood given the disparity between severe functional changes and limited tubular injury. What is clear is that within this complex interplay leading to septic AKI, the inflammatory response plays a pivotal role and hence modulation of this response may translate to improved outcomes. We outline the use of extracorporeal therapies in the treatment of sepsis and septic AKI. We consider the classic aspects of extracorporeal renal replacement therapy including indications, timing, and delivered dose. The various techniques that currently are used to try and achieve immune homeostasis also are outlined. As well as discussing the evidence accumulated to date, we also suggest possibilities for the future treatment of our patients.

HMGB1 Turns Renal Tubular Epithelial Cells into Inflammatory Promoters by Interacting with TLR4 During Sepsis

Our study was undertaken to investigate whether the inflammatory mediator high-mobility group box 1 (HMGB1) can enter the renal tissue and urine and what is the functional change of renal tubular epithelial cells (TECs) interacting with HMGB1 during sepsis. We found that the transcription levels of interleukin 1 (IL-1) and interleukin 6 (IL-6) mRNA in TECs increased significantly during sepsis and these processes can be blocked by splenectomy. We also found out HMGB1 accumulated in the renal tissue and entered urine during sepsis and toll-like receptor 4 (TLR4) was expressed by TECs. In vitro, we demonstrated that HMGB1 induced MAPK and NF-κB activation and G1 cell cycle arrest in TECs. We also found that the mRNA transcription levels of IL-1, IL-6, and tissue inhibitor of metalloproteinases 2 (TIMP2) increased significantly and the IL-1, IL-6, and TIMP2 can be secreted by TECs stimulated by HMGB1. In contrast, LPS RS can block all of the processes above in vitro. In vivo, the increase of the mRNA transcription level of TIMP2 was also observed. These data indicate that HMGB1 accumulates in renal tissue and enters the urine and the interaction between HMGB1 and TLR4 turns TECs into inflammatory promoters during sepsis.

(R)evolution in the Management of Acute Kidney Injury in Newborns

The application of continuous renal replacement therapy (CRRT) in children, before roller pumps and dialysis monitors were available in the intensive care unit, was realized by continuous arteriovenous hemofiltration. Then hemofiltration was coupled with dialysis in order to increase dialytic dose and system efficiency, and the circuit and filters were specifically modified to optimize patency and session life span. After about 30 years, another revolution is ongoing, in that pediatric acute kidney injury (AKI) and fluid accumulation (for which critically ill newborns and children with multiple-organ dysfunction are greatly at risk) are recognized as independently associated with mortality and identified as primary conditions to prevent and aggressively treat. Today, novel technology specifically dedicated for very young patients will allow feasible and straightfoward application of CRRT to infants and children. This article discusses the authors' personal perspectives on how clinical and technical issues of dialysis in children have been addressed and how today, severe pediatric AKI can be managed with accurate and safe CRRT machines that will likely yield outcome improvements in the coming decades.