Mitochondrial Dysfunction is Associated With an Immune Paralysis Phenotype in Pediatric Sepsis.
Ontology highlight
ABSTRACT: Objective
Immune dysregulation is a defining feature of sepsis, but the role for mitochondria in the development of immunoparalysis in pediatric sepsis is not known. We sought to determine if mitochondrial dysfunction measured in peripheral blood mononuclear cells (PBMCs) is associated with immunoparalysis and systemic inflammation in children with sepsis.Design
Prospective observational study.Setting
Single-academic pediatric intensive care unit (PICU).Patients
One hundred sixty-one children with sepsis/septic shock and 18 noninfected PICU controls.Measurements and main results
Mitochondrial respiration in PBMCs, markers of immune function, and plasma cytokines were measured on days 1 to 2 (T1), 3 to 5 (T2), and 8 to 14 (T3) after sepsis recognition, and once for controls. Immunoparalysis was defined as whole-blood ex vivo lipopolysaccharide-induced tumor necrosis factor-alpha (TNF-α) ≤200 pg/mL or monocyte human leukocyte antigen-DR ≤30%. Mitochondrial respiration was lower in children with versus without immunoparalysis measured at the same timepoint. Mitochondrial respiration measured early (at T1 and T2) was also lower in those with immunoparalysis at T2 and T3, respectively. Although most patients with immunoparalysis exhibited low mitochondrial respiration, this metabolic finding was not specific to the immunoparalysis phenotype. Plasma cytokines, including IL-8, IL-10, TNF-α, and MCP-1, were highest in the subset of sepsis patients with immune paralysis or low mitochondrial respiration at T1.Conclusions
Children with sepsis had lower PBMC mitochondrial respiration when immunoparalysis was present compared with those without immunoparalysis. The subsets with immune paralysis and low mitochondrial respiration exhibited the highest levels of systemic inflammation.
SUBMITTER: Weiss SL
PROVIDER: S-EPMC7325426 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:OBJECTIVES:Limited data exist about the timing and significance of mitochondrial alterations in children with sepsis. We therefore sought to determine if alterations in mitochondrial respiration and content within circulating peripheral blood mononuclear cells were associated with organ dysfunction in pediatric sepsis. DESIGN:Prospective observational study SETTING:: Single academic PICU. PATIENTS:One-hundred sixty-seven children with sepsis/septic shock and 19 PICU controls without sepsis, infection, or organ dysfunction. INTERVENTIONS:None. MEASUREMENTS AND MAIN RESULTS:Mitochondrial respiration and content were measured in peripheral blood mononuclear cells on days 1-2, 3-5, and 8-14 after sepsis recognition or once for controls. Severity and duration of organ dysfunction were determined using the Pediatric Logistic Organ Dysfunction score and organ failure-free days through day 28. Day 1-2 maximal uncoupled respiration (9.7?±?7.7 vs 13.7?±?4.1 pmol O2/s/10 cells; p = 0.02) and spare respiratory capacity (an index of bioenergetic reserve: 6.2?±?4.3 vs 9.6?±?3.1; p = 0.005) were lower in sepsis than controls. Mitochondrial content, measured by mitochondrial DNA/nuclear DNA, was higher in sepsis on day 1-2 than controls (p = 0.04) and increased in sepsis patients who had improving spare respiratory capacity over time (p = 0.005). Mitochondrial respiration and content were not associated with day 1-2 Pediatric Logistic Organ Dysfunction score, but low spare respiratory capacity was associated with higher Pediatric Logistic Organ Dysfunction score on day 3-5. Persistently low spare respiratory capacity was predictive of residual organ dysfunction on day 14 (area under the receiver operating characteristic, 0.72; 95% CI, 0.61-0.84) and trended toward fewer organ failure-free days although day 28 (? coefficient, -0.64; 95% CI, -1.35 to 0.06; p = 0.08). CONCLUSIONS:Mitochondrial respiration was acutely decreased in peripheral blood mononuclear cells in pediatric sepsis despite an increase in mitochondrial content. Over time, a rise in mitochondrial DNA tracked with improved respiration. Although initial mitochondrial alterations in peripheral blood mononuclear cells were unrelated to organ dysfunction, persistently low respiration was associated with slower recovery from organ dysfunction.
| S-EPMC7341116 | biostudies-literature
Project description:OBJECTIVES:To describe the epidemiology, morbidity, and mortality of new or progressive multiple organ dysfunction syndrome in children with severe sepsis. DESIGN:Secondary analysis of a prospective, cross-sectional, point prevalence study. SETTING:International, multicenter PICUs. PATIENTS:Pediatric patients with severe sepsis identified on five separate days over a 1-year period. INTERVENTIONS:None. MEASUREMENTS AND MAIN RESULTS:Of 567 patients from 128 PICUs in 26 countries enrolled, 384 (68%) developed multiple organ dysfunction syndrome within 7 days of severe sepsis recognition. Three hundred twenty-seven had multiple organ dysfunction syndrome on the day of sepsis recognition. Ninety-one of these patients developed progressive multiple organ dysfunction syndrome, whereas an additional 57 patients subsequently developed new multiple organ dysfunction syndrome, yielding a total proportion with severe sepsis-associated new or progressive multiple organ dysfunction syndrome of 26%. Hospital mortality in patients with progressive multiple organ dysfunction syndrome was 51% compared with patients with new multiple organ dysfunction syndrome (28%) and those with single-organ dysfunction without multiple organ dysfunction syndrome (10%) (p < 0.001). Survivors of new or progressive multiple organ dysfunction syndrome also had a higher frequency of moderate to severe disability defined as a Pediatric Overall Performance Category score of greater than or equal to 3 and an increase of greater than or equal to 1 from baseline: 22% versus 29% versus 11% for progressive, new, and no multiple organ dysfunction syndrome, respectively (p < 0.001). CONCLUSIONS:Development of new or progressive multiple organ dysfunction syndrome is common (26%) in severe sepsis and is associated with a higher risk of morbidity and mortality than severe sepsis without new or progressive multiple organ dysfunction syndrome. Our data support the use of new or progressive multiple organ dysfunction syndrome as an important outcome in trials of pediatric severe sepsis although efforts are needed to validate whether reducing new or progressive multiple organ dysfunction syndrome leads to improvements in more definitive morbidity and mortality endpoints.
| S-EPMC7261134 | biostudies-literature
Project description:To determine whether treatment with a protocolized sepsis guideline in the emergency department was associated with a lower burden of organ dysfunction by hospital day 2 compared to nonprotocolized usual care in pediatric patients with severe sepsis.Retrospective cohort study.Tertiary care children's hospital from January 1, 2012, to March 31, 2014.Patients older than 56 days old and younger than 18 years old with international consensus defined severe sepsis and who required PICU admission within 24 hours of emergency department arrival were included.The exposure was the use of a protocolized emergency department sepsis guideline. The primary outcome was complete resolution of organ dysfunction by hospital day 2. One hundred eighty nine subjects were identified during the study period. Of these, 121 (64%) were treated with the protocolized emergency department guideline and 68 were not. There were no significant differences between the groups in age, sex, race, number of comorbid conditions, emergency department triage level, or organ dysfunction on arrival to the emergency department. Patients treated with protocolized emergency department care were more likely to be free of organ dysfunction on hospital day 2 after controlling for sex, comorbid condition, indwelling central venous catheter, Pediatric Index of Mortality-2 score, and timing of antibiotics and IV fluids (adjusted odds ratio, 4.2; 95% CI, 1.7-10.4).Use of a protocolized emergency department sepsis guideline was independently associated with resolution of organ dysfunction by hospital day 2 compared to nonprotocolized usual care. These data indicate that morbidity outcomes in children can be improved with the use of protocolized care.
| S-EPMC5008999 | biostudies-literature
Project description:The initial host immune response to sepsis in children is characterized by a proinflammatory surge that can be associated with fever, capillary leak, and organ dysfunction. There is, however, a concurrent anti-inflammatory response that results in hyporesponsiveness of innate and adaptive immune cells. When severe, this response is termed immunoparalysis and is known to be associated with prolonged organ dysfunction, increased risk for nosocomial infection, and death in septic adults and children. Sepsis-induced immune suppression can be defined in the laboratory by reduced whole blood ex vivo - stimulated cytokine production capacities, reduced expression of human leukocyte antigen (HLA)-DR on circulating monocytes, and reduced absolute cell counts. While anti-inflammatory therapies have largely been unsuccessful at improving outcomes from adult and pediatric sepsis, the use of immunostimulatory therapies such as granulocyte macrophage colony-stimulating factor (GM-CSF) in patients with sepsis-induced immunoparalysis shows promise. A greater understanding of the risk factors for immunoparalysis along with the development and execution of immunophenotype-specific clinical trials of strategies to optimize innate and adaptive immune function are needed to further improve outcomes in septic children.
| S-EPMC6506668 | biostudies-literature
Project description:The Pediatric Sepsis Biomarker Risk Model (PERSEVERE), a pediatric sepsis risk model, uses biomarkers to estimate baseline mortality risk for pediatric septic shock. It is unknown how PERSEVERE performs within distinct septic shock phenotypes. We tested PERSEVERE in children with septic shock and thrombocytopenia-associated multiple organ failure (TAMOF), and in those without new onset thrombocytopenia but with multiple organ failure (MOF).PERSEVERE-based mortality risk was generated for each study subject (n = 660). A priori, we determined that if PERSEVERE did not perform well in both the TAMOF and the MOF cohorts, we would revise PERSEVERE to incorporate admission platelet counts.Multiple PICUs in the United States.Standard care.PERSEVERE performed well in the TAMOF cohort (areas under the receiver operating characteristic curves [AUC], 0.84 [95% CI, 0.77-0.90]), but less well in the MOF cohort (AUC, 0.71 [0.61-0.80]). PERSEVERE was revised using 424 subjects previously reported in the derivation phase. PERSEVERE-II had an AUC of 0.89 (0.85-0.93) and performed equally well across TAMOF and MOF cohorts. PERSEVERE-II performed well when tested in 236 newly enrolled subjects. Sample size calculations for a clinical trial testing the efficacy of plasma exchange for children with septic shock and TAMOF indicated PERSEVERE-II-based stratification could substantially reduce the number of patients necessary, when compared with no stratification.Testing PERSEVERE in the context of septic shock phenotypes prompted a revision incorporating platelet count. PERSEVERE-II performs well upon testing, independent of TAMOF or MOF status. PERSEVERE-II could potentially serve as a prognostic enrichment tool.
| S-EPMC5201138 | biostudies-literature
Project description:Cells of the innate and adaptive immune systems play a critical role in the host response to sepsis. Moreover, their accessibility for sampling and their capacity to respond dynamically to an acute threat increases the possibility that leukocytes might serve as a measure of a systemic state of altered responsiveness in sepsis.The working group of the 14th Acute Dialysis Quality Initiative (ADQI) conference sought to obtain consensus on the characteristic functional and phenotypic changes in cells of the innate and adaptive immune system in the setting of sepsis. Techniques for the study of circulating leukocytes were also reviewed and the impact on cellular phenotypes and leukocyte function of nonextracorporeal treatments and extracorporeal blood purification therapies proposed for sepsis was analyzed.A large number of alterations in the expression of distinct neutrophil and monocyte surface markers have been reported in septic patients. The most consistent alteration seen in septic neutrophils is their activation of a survival program that resists apoptotic death. Reduced expression of HLA-DR is a characteristic finding on septic monocytes, but monocyte antimicrobial function does not appear to be significantly altered in sepsis. Regarding adaptive immunity, sepsis-induced apoptosis leads to lymphopenia in patients with septic shock and it involves all types of T cells (CD4, CD8, and Natural Killer) except T regulatory cells, thus favoring immunosuppression. Finally, numerous promising therapies targeting the host immune response to sepsis are under investigation. These potential treatments can have an effect on the number of immune cells, the proportion of cell subtypes, and the cell function.
| S-EPMC4752878 | biostudies-literature
Project description:High mobility group protein 1 (HMGB1) is considered to be the primary inflammatory factor triggering immune paralysis in late-phase sepsis. In this study, however, we wanted to explore the possibility of using HMGB1 to boost local differentiation of bone marrow cells (BMCs) into regulatory dendritic cells (DCs) in vivo, thereby inducing immune reversal in late-phase sepsis and improving the prognosis. For this purpose, sepsis was induced by cecal ligation and puncture (CLP). Mice were injected intraperitoneally with HMGB1 (10, 50, or 250 μg/kg of body weight) 7 days before CLP. BMCs and liver immune cells were isolated at 0, 3, 5, and 7 days post-CLP. Mice were intranasally infected with Pseudomonas aeruginosa 3 days post-CLP as a secondary pneumonia infection model. BMCs and liver cells isolated from septic mice pretreated with HMGB1 were adoptively transferred into CLP mice. GFP+-C57BL/6 and C3H/HeN-C3H/HeJ parabiosis models were established. We found that HMGB1 pretreatment improved the survival of sepsis and increased the numbers of BMCs and liver immune cells in CLP mice. Furthermore, HMGB1 stimulation improved survival in the secondary pneumonia infection model. HMGB1 increased the number as well as the percentage of CD11c- CD45RBhigh DCs in septic BM and liver. Adoptive transfer of septic cells pretreated with HMGB1 into CLP mice attenuated sepsis. HMGB1 enhanced the redistribution of CD11c- CD45RBhigh DCs through TLR4 signaling in parabiosis models. We conclude that HMGB1 triggers immune reversal through the mobilization, redistribution, and local immune differentiation of BMCs, thereby compensating for impaired immunity and leading to sufficient bacterial eradication.
| S-EPMC6105879 | biostudies-literature
Project description:Sepsis is characterized by a dysregulated immune response, metabolic derangements and bioenergetic failure. These alterations are closely associated with a profound and persisting mitochondrial dysfunction. This however occurs despite increased expression of the nuclear-encoded transcription factor A (TFAM) that normally supports mitochondrial biogenesis and functional recovery. Since this paradox may relate to an altered intracellular distribution of TFAM in sepsis, we tested the hypothesis that enhanced extramitochondrial TFAM expression does not translate into increased intramitochondrial TFAM abundance. Accordingly, we prospectively analyzed PBMCs both from septic patients (n = 10) and lipopolysaccharide stimulated PBMCs from healthy volunteers (n = 20). Extramitochondrial TFAM protein expression in sepsis patients was 1.8-fold greater compared to controls (p = 0.001), whereas intramitochondrial TFAM abundance was approximate 80% less (p < 0.001). This was accompanied by lower mitochondrial DNA copy numbers (p < 0.001), mtND1 expression (p < 0.001) and cellular ATP content (p < 0.001) in sepsis patients. These findings were mirrored in lipopolysaccharide stimulated PBMCs taken from healthy volunteers. Furthermore, TFAM-TFB2M protein interaction within the human mitochondrial core transcription initiation complex, was 74% lower in septic patients (p < 0.001). In conclusion, our findings, which demonstrate a diminished mitochondrial TFAM abundance in sepsis and endotoxemia, may help to explain the paradox of lacking bioenergetic recovery despite enhanced TFAM expression.
| S-EPMC7713186 | biostudies-literature
Project description:Autoimmune Disease, Multisystem, with Facial Dysmorphism (ADMFD) is an autosomal recessive disorder due to pathogenic variants in the ITCH gene. It is characterized by failure to thrive, dysmorphic facial features, developmental delay, and systemic autoimmunity that can manifest variably with autoimmune hepatitis, thyroiditis, and enteropathy, among other organ manifestations. It was originally described in 10 consanguineous Old Order Amish patients, and more recently in two patients of White British and Black German ethnicities. While the role of ITCH protein in apoptosis and inflammation has previously been characterized, a defect in cellular bioenergetics has not yet been reported in ITCH deficiency. Here we present a Caucasian female originally evaluated for possible mitochondrial respiratory chain deficiency, who ultimately was found to have two novel variants in ITCH with absence of ITCH protein in patient derived fibroblasts. Clinical studies of patient muscle showed mitochondrial DNA copy number of 57% compared to controls. Functional studies in skin fibroblasts revealed decreased activity of mitochondrial fatty acid oxidation and oxidative phosphorylation, and decreased overall ATP production. Our findings confirm mitochondrial energy dysfunction in a patient with ITCH deficiency offering the opportunity to assess alternative therapeutic options.
| S-EPMC9634006 | biostudies-literature
Project description:Sepsis causes acute kidney injury (AKI) in critically ill patients, although the pathophysiology remains unclear. The receptor-interacting protein kinase-3 (RIPK3), a cardinal regulator of necroptosis, has recently been implicated in the pathogenesis of human disease. In mice subjected to polymicrobial sepsis, we demonstrate that RIPK3 promotes sepsis-induced AKI. Utilizing genetic deletion and biochemical approaches in vitro and in vivo, we identify a potentially novel pathway by which RIPK3 aggravates kidney tubular injury independently of the classical mixed lineage kinase domain-like protein-dependent (MLKL-dependent) necroptosis pathway. In kidney tubular epithelial cells, we show that RIPK3 promotes oxidative stress and mitochondrial dysfunction involving upregulation of NADPH oxidase-4 (NOX4) and inhibition of mitochondrial complex I and -III, and that RIPK3 and NOX4 are critical for kidney tubular injury in vivo. Furthermore, we demonstrate that RIPK3 is required for increased mitochondrial translocation of NOX4 in response to proinflammatory stimuli, by a mechanism involving protein-protein interactions. Finally, we observed elevated urinary and plasma RIPK3 levels in human patients with sepsis-induced AKI, representing potential markers of this condition. In conclusion, we identify a pathway by which RIPK3 promotes kidney tubular injury via mitochondrial dysfunction, independently of MLKL, which may represent a promising therapeutic target in sepsis-induced AKI.
| S-EPMC6124406 | biostudies-literature