Tumor necrosis factor soluble receptors circulate during experimental and clinical inflammation and can protect against excessive tumor necrosis factor alpha in vitro and in vivo.
ABSTRACT Tumor necrosis factor alpha (TNF alpha), a primary mediator of systemic responses to sepsis and infection, can be injurious to the organism when present in excessive quantities. Here we report that two types of naturally occurring soluble TNF receptors (sTNFR-I and sTNFR-II) circulate in human experimental endotoxemia and in critically ill patients and demonstrate that they neutralize TNF alpha-induced cytotoxicity and immunoreactivity in vitro. Utilizing immunoassays that discriminate between total sTNFR-I and sTNFR-I not bound to TNF alpha, we show that sTNFR-I-TNF alpha complexes may circulate even in the absence of detectable free TNF alpha. To investigate the therapeutic possibilities of sTNFR-I, recombinant protein was administered to nonhuman primates with lethal bacteremia and found to attenuate hemodynamic collapse and cytokine induction. We conclude that soluble receptors for TNF alpha are inducible in inflammation and circulate at levels sufficient to block the in vitro cytotoxicity associated with TNF alpha levels observed in nonlethal infection. Administration of sTNFR-I can prevent the adverse pathologic sequelae caused by the exaggerated TNF alpha production observed in lethal sepsis.
SourceAvailable from: Javier Díaz-Castro[Show abstract] [Hide abstract]
ABSTRACT: The objective of the current study was to investigate for the first time and simultaneously the oxidative stress and inflammatory signaling induced during the delivery in healthy mothers and their neonates. 56 mothers with normal gestational course and spontaneous delivery were selected. Blood samples were taken from mother (before and after delivery) both from vein and artery of umbilical cord. Lower antioxidant enzymes activities were observed in neonates compared with their mothers and lower oxidative stress in umbilical cord artery with respect to vein. There was an overexpression of inflammatory cytokines in the mother, such as IL-6 and TNF-α, and, in addition, PGE2 was also increased. Neonates showed lower levels of IL-6 and TNF-α and higher values of sTNF-RII and PGE2 in comparison with their mothers. Parturition increases oxidative damage in the mother, although the indicators of oxidative damage were lower in umbilical cord artery with respect to umbilical vein. The overexpression of inflammatory cytokines reveals that fetus suffers its own inflammatory process during parturition.Oxidative medicine and cellular longevity 02/2015; 2015:178536. DOI:10.1155/2015/178536 · 3.36 Impact Factor
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ABSTRACT: To determine the effect of severe sepsis on monocyte tumor necrosis factor-α-converting enzyme baseline and inducible activity profiles. Observational clinical study. Mixed surgical/medical teaching hospital ICU. Sixteen patients with severe sepsis, 15 healthy volunteers, and eight critically ill patients with noninfectious systemic inflammatory response syndrome. None. Monocyte expression of human leukocyte antigen-D-related peptide, sol-tumor necrosis factor production, tumor necrosis factor-α-converting enzyme expression and catalytic activity, tumor necrosis factor receptor 1 and 2 expression, and shedding at 48-hour intervals from day 0 to day 4, as well as p38-mitogen activated protein kinase expression. Compared with healthy volunteers, both sepsis and systemic inflammatory response syndrome patients' monocytes expressed reduced levels of human leukocyte antigen-D-related peptide and released less sol-tumor necrosis factor on in vitro lipopolysaccharide stimulation, consistent with the term monocyte deactivation. However, patients with sepsis had substantially elevated levels of basal tumor necrosis factor-α-converting enzyme activity that were refractory to lipopolysaccharide stimulation and this was accompanied by similar changes in p38-mitogen activated protein kinase signaling. In patients with systemic inflammatory response syndrome, monocyte basal tumor necrosis factor-α-converting enzyme, and its induction by lipopolysaccharide, appeared similar to healthy controls. Changes in basal tumor necrosis factor-α-converting enzyme activity at day 0 for sepsis patients correlated with Acute Physiology and Chronic Health Evaluation II score and the attenuated tumor necrosis factor-α-converting enzyme response to lipopolysaccharide was associated with increased mortality. Similar changes in monocyte tumor necrosis factor-α-converting enzyme activity could be induced in healthy volunteer monocytes using an in vitro two-hit inflammation model. Patients with sepsis also displayed reduced shedding of monocyte tumor necrosis factor receptors upon stimulation with lipopolysaccharide. Monocyte tumor necrosis factor-α-converting enzyme catalytic activity appeared altered by sepsis and may result in reduced shedding of tumor necrosis factor receptors. Changes seemed specific to sepsis and correlated with illness severity. A better understanding of how tumor necrosis factor-α-converting enzyme function is altered during sepsis will enhance our understanding of sepsis pathophysiology, which will help in the assessment of patient inflammatory status and ultimately may provide new strategies to treat sepsis.Critical care medicine 04/2015; DOI:10.1097/CCM.0000000000000992 · 6.15 Impact Factor
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ABSTRACT: The role of IL-6 in hyperthermia and heat stroke is poorly understood. Plasma IL-6 is elevated following hyperthermia in animals and humans, and IL-6 knockout mice are more intolerant of severe hyperthermia. We evaluated the effect of IL-6 supplementation on organ injury following severe hyperthermia exposure in anesthetized mice. Two hours prior to hyperthermia, mice were treated with 0.6 μg intraperitoneal IL-6, or identical volumes of saline in controls. Mice were anesthetized, gavaged with a FITC dextran for measures of gastrointestinal permeability, and exposed to incremental (0.5°C/30 min) increases in temperature. Heating stopped when maximum core temperature (Tc) of 42.4°C was attained (Tc,max). The mice recovered at room temperature (≈22 °C) for 30 min or 120 min, at which time plasma and tissues were collected. IL-6-treated mice, on average, required ≈25 min longer to attain Tc,max. Injury and swelling of the villi in the duodenum was present in untreated mice after 30 min recovery. These changes were blocked by IL-6 treatment. IL-6 also reduced gastrointestinal permeability, assayed by the accumulation of FITC dextran in plasma. Plasma cytokines were also attenuated in IL-6 treated animals, including significant reductions in TNFα, MCP-1 (CXCL2), RANTES (CCL5) and KC (CCL5). The results demonstrate that IL-6 has a protective influence on the pattern of physiological responses to severe hyperthermia, suggesting that early endogenous expression of IL-6 may provide a protection from the development of organ damage and inflammation.This article is protected by copyright. All rights reservedThe Journal of Physiology 11/2014; 593(3). DOI:10.1113/jphysiol.2014.283416 · 4.54 Impact Factor