Alterations in zinc binding capacity, free zinc levels and total serum zinc in a porcine model of sepsis.

Zinc is crucial for immune function. In addition, the redistribution of zinc and other nutrients due to infection is an integral part of the host immune response to limit availability to pathogens. However, the major zinc binding protein albumin is down regulated during the acute phase response, implicating a decrease in zinc binding capacity. A prospective animal study with eight female German landrace pigs was conducted to investigate alterations in zinc binding capacity, total serum zinc and free zinc levels in the initial phase of sepsis. Sepsis was induced by instillation of autologous feces via midline laparotomy. Total serum zinc declined significantly after 1 h (10.89 ± 0.42 µM vs. 7.67 ± 0.41 µM, p < 0.001), total serum copper and iron reached a significant reduction at 4 h. Urinary excretion of zinc declined in line with total serum zinc. In comparison to total serum zinc, free zinc levels declined to a lesser, though significant, extent. Zinc binding capacity of serum decreased over time, whereby free zinc levels after addition of zinc correlated negatively with total serum protein and albumin levels. In addition IL-6 and TNF-α concentrations were measured and increased significantly 2 h after induction of sepsis. Hence, total serum zinc was the first marker of inflammation in our experiment, and might therefore be a promising biomarker for the early diagnosis of sepsis. Furthermore the observation of a substantially different serum free zinc homeostasis during sepsis provides valuable information for a potential therapeutic zinc supplementation, which has to take buffering capacity by serum proteins into account.

The anti-inflammatory effect of the synthetic antimicrobial peptide 19-2.5 in a murine sepsis model: a prospective randomized study.

INTRODUCTION: Increasing rates of multi-resistant bacteria are a major problem in the treatment of critically ill patients. Furthermore, conventional antibiotics lead to the release of bacterial derived membrane parts initiating pro-inflammatory cascades with potential harm to the patient. Antimicrobial peptides (AMP) may kill bacteria without releasing pro-inflammatory factors. Thus, we compared three newly developed synthetic anti-lipopolysaccharide peptides (SALPs) with a broader range of efficacy to suppress cytokine release in plasma and CD14 mRNA expression in organ tissue in a murine, polymicrobial sepsis model. METHODS: A randomized, experimental trial was conducted in an animal research facility. Male NMRI mice (n = 90; 8- to 12-weeks old) were randomized to the following six groups: (i) sham operation and parenteral vehicle (NaCl 0.9%) administration (sham); (ii) cecal ligation and puncture (CLP) and vehicle infusion (sepsis-control), (iii) CLP and polymyxin B infusion (polyB), or (iv to vi) CLP and infusion of three different synthetic antimicrobial peptides Peptide 19-2.5 (Pep2.5), Peptide 19-4 (Pep4) or Peptide 19-8 (Pep8). All animals underwent arterial and venous catheterization for hemodynamic monitoring 48 hours prior to CLP or sham-operation. Physical appearance and behavior (activity), plasma cytokine levels, and CD14 mRNA expression in heart, lung, liver, spleen and kidney tissue were determined 24 hours after CLP or sham operation. RESULTS: Only Pep2.5 significantly enhanced the activity after CLP, whereas none of the therapeutic regimens elevated the mean arterial pressure or heart rate. The strongly elevated IL-6, IL-10 and monocyte chemoattractant protein serum levels in septic animals were significantly reduced after Pep2.5 administration (P < 0.001, P < 0.001, and P < 0.001, respectively). Similarly, Pep2.5 significantly reduced the sepsis-induced CD14 mRNA expression in heart (P = 0.003), lung (P = 0.008), and spleen tissue (P = 0.009) but not in kidney and liver. CONCLUSIONS: Structurally variable SALPs exhibit major differences in their anti-inflammatory effect in vivo. Continuous parenteral administration of Pep2.5 is able to reduce sepsis-induced cytokine release and tissue inflammation.

Plasma adrenomedullin in critically ill patients with sepsis after major surgery: A pilot study.

PURPOSE: Adrenomedullin is released by different tissues in hypoxia, oxidative stress, and inflammation and is found in general and medical patients and, recently, in sepsis patients in emergency departments. The aim of this study was to evaluate biologically active adrenomedullin that mirrors directly the active peptide levels in plasma of surgical intensive care unit (ICU) patients with sepsis. MATERIALS AND METHODS: In this single-center observational pilot trial, 42 ICU patients with sepsis and 14 patients after major surgery were included after sepsis diagnosis or ICU admission. RESULTS: Patients (66% male) were 70 (median) (interquartile range [IQR], 61-77]) years old and had a body mass index of 26.2 (24.2-29.4) kg/m2. The ICU and hospital length of stay was 8 (1-22) and 17 (8-21) days, respectively. Eight patients had sepsis, 19 developed severe sepsis, and 15 suffered from septic shock. Adrenomedullin increased with severity (sepsis: 25.8 pg/mL [IQR 20.3-40.2], severe sepsis: 84.2 pg/mL [IQR 42.7-118.5], septic shock: 119.7 pg/mL [IQR 83.8-172.6]; P<.0001). Higher adrenomedullin was associated with poor 90-day outcomes (P=.019) and more frequent vasopressor use (P=.001). CONCLUSIONS: This is the first study investigating adrenomedullin in patients with sepsis following major surgery. Higher adrenomedullin on admission is associated with increased vasopressor need and mortality after 90 days. Thus, adrenomedullin may be a useful additional parameter in surgical patients with sepsis.

Antimicrobial Peptides in Human Sepsis.

Nearly 100 years ago, antimicrobial peptides (AMPs) were identified as an important part of innate immunity. They exist in species from bacteria to mammals and can be isolated in body fluids and on surfaces constitutively or induced by inflammation. Defensins have anti-bacterial effects against Gram-positive and Gram-negative bacteria as well as anti-viral and anti-yeast effects. Human neutrophil peptides (HNP) 1-3 and human beta-defensins (HBDs) 1-3 are some of the most important defensins in humans. Recent studies have demonstrated higher levels of HNP 1-3 and HBD-2 in sepsis. The bactericidal/permeability-increasing protein (BPI) attenuates local inflammatory response and decreases systemic toxicity of endotoxins. Moreover, BPI might reflect the severity of organ dysfunction in sepsis. Elevated plasma lactoferrin is detected in patients with organ failure. HNP 1-3, lactoferrin, BPI, and heparin-binding protein are increased in sepsis. Human lactoferrin peptide 1-11 (hLF 1-11) possesses antimicrobial activity and modulates inflammation. The recombinant form of lactoferrin [talactoferrin alpha (TLF)] has been shown to decrease mortality in critically ill patients. A phase II/III study with TLF in sepsis did not confirm this result. The growing number of multiresistant bacteria is an ongoing problem in sepsis therapy. Furthermore, antibiotics are known to promote the liberation of pro-inflammatory cell components and thus augment the severity of sepsis. Compared to antibiotics, AMPs kill bacteria but also neutralize pathogenic factors such as lipopolysaccharide. The obstacle to applying naturally occurring AMPs is their high nephro- and neurotoxicity. Therefore, the challenge is to develop peptides to treat septic patients effectively without causing harm. This overview focuses on natural and synthetic AMPs in human and experimental sepsis and their potential to provide significant improvements in the treatment of critically ill with severe infections.

Peptide 19-2.5 inhibits heparan sulfate-triggered inflammation in murine cardiomyocytes stimulated with human sepsis serum.

Myocardial dysfunction in sepsis has been linked to inflammation caused by pathogen-associated molecular patterns (PAMPs) as well as by host danger-associated molecular patterns (DAMPs). These include soluble heparan sulfate (HS), which triggers the devastating consequences of the pro-inflammatory cascades in severe sepsis and septic shock. Thus, there is increasing interest in the development of anti-infective agents, with effectiveness against both PAMPs and DAMPs. We hypothesized that a synthetic antimicrobial peptide (peptide 19-2.5) inhibits inflammatory response in murine cardiomyocytes (HL-1 cells) stimulated with PAMPs, DAMPs or serum from patients with septic shock by reduction and/or neutralization of soluble HS. In the current study, our data indicate that the treatment with peptide 19-2.5 decreases the inflammatory response in HL-1 cells stimulated with either PAMPs or DAMPs. Furthermore, our work shows that soluble HS in serum from patients with Gram-negative or Gram-positive septic shock induces a strong pro-inflammatory response in HL-1 cells, which can be effectively blocked by peptide 19-2.5. Based on these findings, peptide 19-2.5 is a novel anti-inflammatory agent interacting with both PAMPs and DAMPs, suggesting peptide 19-2.5 may have the potential for further development as a broad-spectrum anti-inflammatory agent in sepsis-induced myocardial inflammation and dysfunction.