Dieter Falkenhagen (1942–2015): A Multifaceted Scientist

A New Integrated Technique for the Supportive Treatment of Sepsis

Although there has been continuous, intensive research for many years in the field of sepsis treatment, currently available treatment options are limited, and there is still a lack of systems that efficiently remove endotoxins as well as mediators. Here, we discuss a newly developed, integrated technique that combines different aspects for their use in extracorporeal blood purification for the supportive treatment of liver failure and sepsis.

The role of ionized calcium and magnesium in regional citrate anticoagulation and its impact on inflammatory parameters

INTRODUCTION

Regional anticoagulation with citrate has been found to be superior to heparin in terms of biocompatibility, and numerous protocols for regional citrate anticoagulation have been published, while a consensus on the target concentration of ionized calcium (Ca2+) in the extracorporeal circuit has not been reached so far.

METHODS

The aim of this in vitro study was to assess the impact of different citrate concentrations on coagulation as well as on complement activation and cytokine secretion and to investigate the impact of ionized magnesium (Mg2+) on these parameters.

RESULTS

We found that citrate effectively reduced coagulation, complement activation, and cytokine secretion in a dose-dependent manner and that a target Ca2+ concentration of 0.2-0.25 mM was required for efficient anticoagulation. Mg2+ triggered complement activation as well as interleukin (IL)-1β secretion in lipopolysaccharide (LPS)-stimulated whole blood in a dose-dependent manner and independently of Ca2+. Additionally, it was found to reduce activated clotting time (ACT) in samples with low Ca2+ levels, but not at physiological Ca2+.

CONCLUSIONS

Taken together, our data support the notion that regional citrate anticoagulation results in decreased release of inflammatory mediators in the extracorporeal circuit, requiring the depletion of both, Ca2+ and Mg2+.

Mechanisms of endothelial activation in sepsis and cell culture models to study the heterogeneous host response

Sepsis is currently viewed as a fundamental disintegration of control functions from intracellular signalling to immunoregulatory and neuroendocrine mechanisms. The immediate threat in sepsis is invasive infection, and the need to activate immune defense mechanisms to clear the pathogen before irreparable damage occurs. In the process of pathogen elimination, however, the systemic host response to infection may cause collateral damage to the endothelium and may lead to the destruction of host tissues.A number of experimental models have been developed to monitor endothelial activation and to study endothelial dysfunction under septic conditions. Here, we review the application of these models to assess the highly variable host response in sepsis and to investigate the efficacy of adsorbent-based extracorporeal therapies. We also highlight the need for efficient diagnostic tools, which are indispensable to select patients who are likely to benefit from distinct adjunctive therapies.

Biomimetic Principles to Develop Blood Compatible Surfaces

Functionalized biomaterial surface patterns capable of resisting nonspecific adsorption while retaining their bioactivity are crucial in the advancement of biomedical technologies, but currently available biomaterials intended for use in whole blood frequently suffer from nonspecific adsorption of proteins and cells, leading to a loss of activity over time. In this review, we address two concepts for the design and modification of blood compatible biomaterial surfaces, zwitterionic modification and surface functionalization with glycans – both of which are inspired by the membrane structure of mammalian cells – and discuss their potential for biomedical applications.