[Role of the innate immune response in sepsis]

The Good and the Bad: Monocytes' and Macrophages' Diverse Functions in Inflammation

Monocytes and macrophages are central players of the innate immune response and play a pivotal role in the regulation of inflammation. Thereby, they actively participate in all phases of the immune response, from initiating inflammation and triggering the adaptive immune response, through to the clearance of cell debris and resolution of inflammation. In this review, we described the mechanisms of monocyte and macrophage adaptation to rapidly changing microenvironmental conditions and discussed different forms of macrophage polarization depending on the environmental cues or pathophysiological condition. Therefore, special focus was placed on the tight regulation of the pro- and anti-inflammatory immune response, and the diverse functions of S100A8/S100A9 proteins and the scavenger receptor CD163 were highlighted, respectively. We paid special attention to the function of pro- and anti-inflammatory macrophages under pathological conditions.

Critical Parameters in Dynamic Network Modeling of Sepsis

In this work, we propose a dynamical systems perspective on the modeling of sepsis and its organ-damaging consequences. We develop a functional two-layer network model for sepsis based upon the interaction of parenchymal cells and immune cells via cytokines, and the coevolutionary dynamics of parenchymal, immune cells, and cytokines. By means of the simple paradigmatic model of phase oscillators in a two-layer system, we analyze the emergence of organ threatening interactions between the dysregulated immune system and the parenchyma. We demonstrate that the complex cellular cooperation between parenchyma and stroma (immune layer) either in the physiological or in the pathological case can be related to dynamical patterns of the network. In this way we explain sepsis by the dysregulation of the healthy homeostatic state (frequency synchronized) leading to a pathological state (desynchronized or multifrequency cluster) in the parenchyma. We provide insight into the complex stabilizing and destabilizing interplay of parenchyma and stroma by determining critical interaction parameters. The coupled dynamics of parenchymal cells (metabolism) and nonspecific immune cells (response of the innate immune system) is represented by nodes of a duplex layer. Cytokine interaction is modeled by adaptive coupling weights between nodes representing immune cells (with fast adaptation timescale) and parenchymal cells (slow adaptation timescale), and between pairs of parenchymal and immune cells in the duplex network (fixed bidirectional coupling). The proposed model allows for a functional description of organ dysfunction in sepsis and the recurrence risk in a plausible pathophysiological context.

Does nano-curcumin supplementation improve hematological indices in critically ill patients with sepsis? A randomized controlled clinical trial

Sepsis is the final common pathway to death for severe infectious diseases worldwide. The present trial aimed to investigate the effects of nano-curcumin supplementation on hematological indices in critically ill patients with sepsis. Fourteen ICU-admitted patients were randomly allocated into either nano-curcumin or placebo group for 10 days. The blood indices, serum levels of inflammatory biomarker and presepsin as well as nutrition status, and clinical outcomes were assessed before the intervention and on days 5 and 10. White blood cells, neutrophils, platelets, erythrocyte sedimentation rate (ESR), and the levels of interleukin-8 significantly decreased in the nano-curcumin group compared to the placebo after 10 days of intervention (p = .024, p = .045, p = .017, p = .041, and p = .004, respectively). There was also a marginal meaningful decrease in serum presepsin levels in the intervention group compared to the placebo at the end of the study (p = .054). However, total lymphocyte count showed a significant increase in the nano-curcumin group compared to the placebo at the end-point (p = .04). No significant differences were found in the level of lymphocyte and the ratios of neutrophil/lymphocyte and platelet/lymphocyte between the study groups. Moreover, no significant between-group differences were observed for other study outcomes, post-intervention. Collectively, nano-curcumin may be a useful adjuvant therapy in critically ill patients with sepsis. However, further trials are suggested to examine the effects of nano-curcumin in the management of sepsis and its complications. PRACTICAL APPLICATIONS: Curcumin (1,7-bis[4-hydroxy-3-methoxyphenyl]-1,6-heptadiene-3,5- dione) or diferuloylmethane is widely used in medicine due to its several biological properties. Recent evidence has shown that curcumin possesses multiple pharmacological activities including immune-modulatory, antioxidant, anti-inflammatory, anti-cancer, and anti-microbial effects. In this study, it was observed that nano-curcumin at a dose of 160 mg for 10 days, without side effects, reduced some inflammatory factors and regulated the immune responses in sepsis patients. For the first time, this trial was conducted to determine the effect of nano-curcumin on hematological indices and the serum levels of presepsin and IL-8.

Aspects of tumor progression

A model is introduced here that for the first time describes carcinogenesis in the context of and interacting with associated inflammatory processes. Central to the model are the control of cytokine production by the innate immune system and its disturbance by additional uncontrolled cytokine sources. The model aims to answer the following questions: Why don't tumors form more often? What drives tumor recurrence after an R0 surgery even in UICC I cases, and what causes tumor progression? Which are the host-tumor-host interactions that ultimately lead to lethal outcome in the disease? The model describes the innate immune system under normal conditions as in a dynamic equilibrium, which is shifted toward pro-inflammation when a tumor forms. That in turn causes tumor-associated symptoms, metastasis, and tumor relapse. The recurrence of the tumor from R0/N0/M0-conditions results from the activation of a memory function of the innate immune system, which is conditioned during the initial tumor growth and survives the tumor removal. If activated, this memory function reestablishes, often irreversibly, the shift of the innate immune system away from dynamic equilibrium toward a pro-inflammatory state characterized by nonspecific symptoms originating from the tumor and by activation of dissemination of tumor cells. Once disseminated, these cells can proliferate and form new metastatic structures. Although elements of the memory function are unclear, some properties can be derived from the relapse behavior of tumors. A therapeutic path to influence the innate immune system could be an element in oncologic therapy: Reducing the deviation from the dynamic equilibrium would diminish the clinical effects of such a disturbance and decouple the presence of tumor cells from the influence they have on the organism, and thus build a resilience to tumor growth. The model presented here could also influence sepsis and SIRS therapy and possibly other diseases for which the innate immune system is disturbed.

Binge-Like Exposure to Ethanol Enhances Morphine's Anti-nociception in B6 Mice

Elevation of the blood ethanol concentration (BEC) to > 80 mg/dL (17.4 mM) after binge drinking enhances inflammation in brain and neuroimmune signaling pathways. Morphine abuse is frequently linked to excessive drinking. Morphine exerts its actions mainly via the seven transmembrane G-protein-coupled mu opioid receptors (MORs). Opioid use disorders (OUDs) include combination of opioids with alcohol, leading to opioid overdose-related deaths. We hypothesized that binge drinking potentiates onset and progression of OUD. Using C57BL/6J (B6) mice, we first characterized time-dependent inflammatory gene expression change as molecular markers using qRT-PCR within 24 h after binge-like exposure to high-dose, high-concentration ethanol (EtOH). The mice were given one injection of EtOH (5 g/kg, 42% v/v, i.g.) and sacrificed at 2.5 h, 5 h, 7.5 h, or 24 h later. Inflammatory cytokines interleukin (IL)-1β, IL-6, and IL-18 were elevated in both the striatum (STr) and the nucleus accumbens (NAc) of the mice. We then investigated the expression profile of MOR in the STr at 2 min, 5 h, or 24 h after the first EtOH injection and at 24 h and 48 h after the third injection. This binge-like exposure to EtOH upregulated MOR expression in the STr and NAc, an effect that could enhance morphine's anti-nociception. Therefore, we examined the impact of binge-like exposure to EtOH on morphine's anti-nociception at the behavioral level. The mice were treated with or without 3-d binge-like exposure to EtOH, and the anti-nociceptive changes were evaluated using the hot-plate test 24 h after the final (3rd) EtOH injection with or without a cumulative subcutaneous dose (0, 0.1, 0.3, 1.0, and 3.0 mg/kg) of morphine at intervals of 30 min. The response curve of the mice given EtOH was shifted to the left, showing enhanced latency to response to morphine up to 3 mg/kg. Furthermore, co-treatment with the MOR antagonist naltrexone blocked morphine's anti-nociception in animals given either EtOH or saline. This confirms that MOR is involved in binge-like exposure to EtOH-induced changes in morphine's anti-nociception. Our results suggest that EtOH enhanced latency to analgesic response to morphine, and such effect might initiate the onset and progression of OUDs.

Blurring borders: innate immunity with adaptive features

Adaptive immunity has often been considered the penultimate of immune capacities. That system is now being deconstructed to encompass less stringent rules that govern its initiation, actual effector activity, and ambivalent results. Expanding the repertoire of innate immunity found in all invertebrates has greatly facilitated the relaxation of convictions concerning what actually constitutes innate and adaptive immunity. Two animal models, incidentally not on the line of chordate evolution (C. elegans and Drosophila), have contributed enormously to defining homology. The characteristics of specificity and memory and whether the antigen is pathogenic or nonpathogenic reveal considerable information on homology, thus deconstructing the more fundamentalist view. Senescence, cancer, and immunosuppression often associated with mammals that possess both innate and adaptive immunity also exist in invertebrates that only possess innate immunity. Strict definitions become blurred casting skepticism on the utility of creating rigid definitions of what innate and adaptive immunity are without considering overlaps.

[The diagnosis of sepsis]

The early diagnosis of sepsis is mandatory for the further reduction of mortality due to sepsis. Current findings exist that accentuate the role of the time factor, comparable with acute myocardial infarction or with ischemic stroke. On the other hand, there are no generally accepted diagnostics for sepsis, realizing the demands of early diagnosis and based on the physician's experience.The diagnostics start with the recognition of the inflammatory reaction caused by infection (at least 2 of 4 criteria of inflammatory reaction have to be fulfilled). This definition has high sensitivity, but remarkably lower specificity and it leads either to too frequent admissions or only to hospitalization in case of a complicating organ failure. Making a careful history and knowledge about sepsis are essential for the out-patient department physicians. In addition to the varying pictures of sepsis, the clinicians have laboratory findings available, most of all procalcitonin. Patients have to be considered as septic with a serum PCT level higher than 1 ng/ml particularly when clinical signs do not exclude sepsis and in cases of positive blood cultures. Initially PCT is a product of macrophages if the defense reaction starts, but it becomes an infection marker, when the serum PCT level declines less than the half life falls.

Die Diagnose der Sepsis

Die frühe Diagnostik der Sepsis ist das Nadelöhr für die weitere Senkung der Sepsissterblichkeit. Inzwischen liegen Befunde vor, dass, vergleichbar mit akutem Myokardinfarkt und Schlaganfall, dem Faktor Zeit eine wichtige Rolle zukommt. Demgegenüber gibt es keine allgemein akzeptierte Sepsisdiagnostik, die der Forderung nach früher Diagnose und der Unabhängigkeit vom Erfahrungsstand des jeweiligen Arztes Rechnung tragen könnte.