Ccr2 Dependent Monocytes Exacerbate Intestinal Inflammation and Modulate Gut Serotonergic Signaling Following Traumatic Brain Injury.

BACKGROUND: Traumatic brain injury (TBI) leads to acute gastrointestinal dysfunction and mucosal damage, resulting in feeding intolerance. Ccr2+ monocytes are crucial immune cells that regulate the gut's inflammatory response via the brain-gut axis. Using CCR2KO mice, we investigated the intricate interplay between these cells to better elucidate the role of systemic inflammation after TBI. METHODS: A murine-controlled cortical impact model was utilized, and results were analyzed on post-injury days (PID) 1 and 3. The experimental groups included (1) Sham C57Bl/6 wild-type (WT), (2) TBI WT, (3) Sham CCR2KO and (4) TBI CCR2KO. Mice were euthanized on PID 1 and 3 to harvest the ileum and study intestinal dysfunction and serotonergic signaling using a combination of quantitative real-time PCR (qRT-PCR), immunohistochemistry, FITC-dextran motility assays, and flow cytometry. Student's t-test and one-way ANOVA were used for statistical analysis, with significance achieved when p < 0.05. RESULTS: TBI resulted in severe dysfunction and dysmotility of the small intestine in WT mice as established by significant upregulation of inflammatory cytokines iNOS, Lcn2, TNFα, and IL1ß and the innate immunity receptor toll-like receptor 4 (Tlr4). This was accompanied by disruption of genes related to serotonin synthesis and degradation. Notably, CCR2KO mice subjected to TBI showed substantial improvements in intestinal pathology. TBI CCR2KO groups demonstrated reduced expression of inflammatory mediators (iNOS, Lcn2, IL1ß, and Tlr4) and improvement in serotonin synthesis genes, including tryptophan hydroxylase 1 (Tph1) and dopa decarboxylase (Ddc). CONCLUSION: Our study reveals a critical role for Ccr2+ monocytes in modulating intestinal homeostasis after TBI. Ccr2+ monocytes aggravate intestinal inflammation and alter gut-derived serotonergic signaling. Therefore, targeting Ccr2+ monocyte-dependent responses could provide a better understanding of TBI-induced gut inflammation. Further studies are required to elucidate the impact of these changes on brain neuroinflammation and cognitive outcomes. STUDY TYPE: Original Article (Basic Science, level of evidence N/A).

Pharmacologic Toll-like receptor 4 inhibition skews toward a favorable A1/A2 astrocytic ratio improving neurocognitive outcomes following traumatic brain injury.

BACKGROUND: Astrocytes are critical neuroimmune cells that modulate the neuroinflammatory response following traumatic brain injury (TBI) because of their ability to acquire neurotoxic (A1) or neuroprotective (A2) phenotypes. Using C34, a novel pharmacologic Toll-like receptor (TLR) 4 inhibitor, we explored their respective polarization states after TBI. METHODS: A murine controlled cortical impact model was used, and the results were analyzed on postinjury days (PIDs) 1, 7, and 28. The experimental groups are as follows: (1) sham, (2) sham + C34, (3) TBI, and (4) TBI + C34. Quantitative real-time polymerase chain reaction was used to quantify gene expression associated with proinflammatory (A1) and anti-inflammatory (A2) phenotypes. Morris water maze was used to assess neurocognitive outcomes. Fixed frozen cortical samples were sectioned, stained for myelin basic protein and 4',6-diamidino-2-phenylindole, and then imaged. Student t test and one-way analysis of variance were used for statistical analysis with significance achieved when p < 0.05. RESULTS: On quantitative real-time polymerase chain reaction, C34-treated groups showed a significant decrease in the expression of A1 markers such as Gbp2 and a significant increase in the expression of A2 markers such as Emp1 when compared with untreated groups on PID 1. On PIDs 7 and 28, the expression of most A1 and A2 markers was also significantly decreased in the C34-treated groups. On immunohistochemistry, C34-treated groups demonstrated increased myelin basic protein staining into the lesion by PID 28. C34-treated groups showed more platform entries on Morris water maze when compared with untreated groups on PID 7 and PID 28. CONCLUSION: Following TBI, early TLR4 blockade modulates astrocytic function and shifts its polarization toward the anti-inflammatory A2-like phenotype. This is accompanied by an increase in myelin regeneration, providing better neuroprotection and improved neurocognitive outcomes. Targeting A1/A2 balance with TLR4 inhibition provides a potential therapeutic target to improve neurobehavioral outcomes in the setting of TBI.

Infiltrating anti-inflammatory monocytes modulate microglial activation through toll-like receptor 4/interferon-dependent pathways following traumatic brain injury.

BACKGROUND: Traumatic brain injury (TBI) is the leading cause of morbidity and mortality in the pediatric population. Microglia and infiltrating monocyte-derived macrophages are crucial immune cells that modulate the neuroinflammatory response following TBI. Using C34, a novel pharmacologic toll-like receptor 4 inhibitor, we investigated the intricate interactions between these cells in a murine TBI model. METHODS: A murine controlled cortical impact model was used, and the results were analyzed on postinjury days 1, 7, 28, and 35. The experimental groups are as follows: (1) sham C57BL/6 wild-type (WT), (2) TBI WT, (3) sham WT + C34, and (4) TBI WT + C34. Quantitative real-time polymerase chain reaction was used to quantify gene expression associated with microglial activation, apoptotic pathways, and type 1 interferon pathway. Flow cytometry was used to isolate microglia and infiltrating monocytes. Brain lesion volumes were assessed using magnetic resonance imaging. Last, neurocognitive outcomes were evaluated using the Morris Water Maze test. Student's t test and one-way analysis of variance were used for statistical analysis with significance achieved when p < 0.05. RESULTS: Toll-like receptor 4 inhibition leads to improved neurological sequela post-TBI, possibly because of an increase in infiltrating anti-inflammatory monocytes and a decrease in IFN regulatory factor 7 during acute inflammation, followed by a reduction in apoptosis and M2 microglial expression during chronic inflammation. CONCLUSION: Toll-like receptor 4 inhibition with C34 skews infiltrating monocytes toward an anti-inflammatory phenotype, leading to enhanced neurocognitive outcomes. Moreover, although M2 microglia have been consistently shown as inducers of neuroprotection, our results clearly demonstrate their detrimental role during the chronic phases of healing post-TBI.

Incidental Meckel's Diverticulum With Neuroendocrine Tumor.

Meckel's diverticulum (MD), the most common congenital disease of the small bowel, commonly presents with symptoms of painless rectal bleeding and intestinal obstruction. The treatment of symptomatic MD involves resection of the lesion regardless of patient age; however, the excision of asymptomatic and incidentally identified MDs in adults remain controversial. On one hand, the complications arising from MDs decrease with age, leading to a lower benefit than risk ratio with prophylactic resection. On the other hand, malignancies, such as neuroendocrine tumors, may arise over time from untreated MDs. This can lead to poor prognostic complications, such as liver or lymph node metastases. In this case report, we describe an incidental Meckel's diverticulum discovered during an exploratory laparotomy for acute sigmoid diverticulitis in an adult male. Later biopsy findings discovered the lesion to contain a grade 1 neuroendocrine tumor. Based on our literature review findings, resection of the incidental Meckel's diverticulum was a reasonable approach given the low complication risks of the procedure and the possibility of malignant transformation and progression.

The administration of a pre-digested fat-enriched formula prevents necrotising enterocolitis-induced lung injury in mice.

Necrotising enterocolitis (NEC) is a devastating gastrointestinal disease of prematurity that typically develops after the administration of infant formula, suggesting a link between nutritional components and disease development. One of the most significant complications that develops in patients with NEC is severe lung injury. We have previously shown that the administration of a nutritional formula that is enriched in pre-digested Triacylglyceride that do not require lipase action can significantly reduce the severity of NEC in a mouse model. We now hypothesise that this 'pre-digested fat (PDF) system' may reduce NEC-associated lung injury. In support of this hypothesis, we now show that rearing newborn mice on a nutritional formula based on the 'PDF system' promotes lung development, as evidenced by increased tight junctions and surfactant protein expression. Mice that were administered this 'PDF system' were significantly less vulnerable to the development of NEC-induced lung inflammation, and the administration of the 'PDF system' conferred lung protection. In seeking to define the mechanisms involved, the administration of the 'PDF system' significantly enhanced lung maturation and reduced the production of reactive oxygen species (ROS). These findings suggest that the PDF system protects the development of NEC-induced lung injury through effects on lung maturation and reduced ROS in the lung and also increases lung maturation in non-NEC mice.

A Central Role for Lipocalin-2 in the Adaptation to Short-Bowel Syndrome Through Down-Regulation of IL22 in Mice.

BACKGROUND & AIMS: In short-bowel syndrome (SBS), inadequate intestinal adaptation is responsible for the majority of complications, including sepsis, liver failure, and death. In this study, we sought to further delineate the adaptive response to identify potential therapeutic targets. METHODS: We performed a 75% small-bowel resection (SBR) or sham operation on C57Bl/6J wild-type (WT), lipocalin-2 (LCN2)-/-, and interleukin 22 (IL22)-/- mice. Exogenous IL22 was administered to SBR WT mice. Cecal fecal matter from SBR WT and SBR LCN2-/- mice were transplanted into germ-free mice. Intestinal permeability, inflammation, proliferation, and the microbiome were evaluated 1 week after surgery. CD4+IL22+ laminal propria lymphocytes were sorted by flow cytometry. Naïve T cells were polarized to T-helper cells with or without LCN2. RESULTS: A 75% SBR in a mouse re-creates the increased intestinal permeability, enterocyte proliferation, and intestinal dysbiosis seen in SBS. LCN2 expression increases after 75% SBR, and this increase can be abrogated with broad-spectrum antibiotic treatment. LCN2-/- mice have less intestinal inflammation, increased IL22 expression, and greater adaptation as evidenced by less intestinal permeability, increased carbohydrate enzyme expression, less weight loss, and less dysbiosis after 75% SBR than WT mice. The proinflammatory and anti-adaptive effects of LCN2 can be transferred to germ-free mice via a fecal transplant. Administration of exogenous IL22 improves adaptation and restores the normal microbiome after 75% SBR in WT mice. CONCLUSIONS: LCN2 promotes inflammation and slows intestinal adaptation through changes in the microbiome and IL22 inhibition in a mouse SBS model. Strategies to reduce LCN2 may offer novel therapeutic approaches to enhance adaptation in SBS.

Machine Learning Can Improve Estimation of Surgical Case Duration: A Pilot Study.

Operating room (OR) utilization is a significant determinant of hospital profitability. One aspect of this is surgical scheduling, which depends on accurate predictions of case duration. This has been done historically by either the surgeon based on personal experience, or by an electronic health record (EHR) based on averaged historical means for case duration. Here, we compare the predicted case duration (pCD) accuracy of a novel machine-learning algorithm over a 3-month period. A proprietary machine learning algorithm was applied utilizing operating room factors such as patient demographic data, pre-surgical milestones, and hospital logistics and compared to that of a conventional EHR. Actual case duration and pCD (Leap Rail vs EHR) was obtained at one institution over the span of 3 months. Actual case duration was defined as time between patient entry into an OR and time of exit. pCD was defined as case time allotted by either Leap Rail or EHR. Cases where Leap Rail was unable to generate a pCD were excluded. A total of 1059 surgical cases were performed during the study period, with 990 cases being eligible for the study. Over all sub-specialties, Leap Rail showed a 7 min improvement in absolute difference between pCD and actual case duration when compared to conventional EHR (p < 0.0001). In aggregate, the Leap Rail method resulted in a 70% reduction in overall scheduling inaccuracy. Machine-learning algorithms are a promising method of increasing pCD accuracy and represent one means of improving OR planning and efficiency.

Toll Like Receptor 4 Mediated Lymphocyte Imbalance Induces Nec-Induced Lung Injury.

Necrotizing enterocolitis (NEC) is the leading cause of death from gastrointestinal disease in premature infants, and is associated with the development of severe lung inflammation. The pathogenesis of NEC-induced lung injury remains unknown, yet infiltrating immune cells may play a role. In support of this possibility, we now show that NEC in mice and humans was associated with the development of profound lung injury that was characterized by an influx of Th17 cells and a reduction in T regulatory lymphocytes (Tregs). Importantly, the adoptive transfer of CD4 T cells isolated from lungs of mice with NEC into the lungs of immune incompetent mice (Rag1 mice) induced profound inflammation in the lung, while the depletion of Tregs exacerbated NEC induced lung injury, demonstrating that imbalance of Th17/Treg in the lung is required for the induction of injury. In seeking to define the mechanisms involved, the selective deletion of toll-like receptor 4 (TLR4) from the Sftpc1 pulmonary epithelial cells reversed lung injury, while TLR4 activation induced the Th17 recruiting chemokine (C-C motif) ligand 25 (CCL25) in the lungs of mice with NEC. Strikingly, the aerosolized inhibition of both CCL25 and TLR4 and the administration of all trans retinoic acid restored Tregs attenuated NEC-induced lung injury. In summary, we show that TLR4 activation in Surfactant protein C-1 (Sftpc1) cells disrupts the Treg/Th17 balance in the lung via CCL25 leading to lung injury after NEC and reveal that inhibition of TLR4 and stabilization of Th17/Treg balance in the neonatal lung may prevent this devastating complication of NEC.

Cognitive impairments induced by necrotizing enterocolitis can be prevented by inhibiting microglial activation in mouse brain.

Necrotizing enterocolitis (NEC) is a severe gastrointestinal disease of the premature infant. One of the most important long-term complications observed in children who survive NEC early in life is the development of profound neurological impairments. However, the pathways leading to NEC-associated neurological impairments remain unknown, thus limiting the development of prevention strategies. We have recently shown that NEC development is dependent on the expression of the lipopolysaccharide receptor Toll-like receptor 4 (TLR4) on the intestinal epithelium, whose activation by bacteria in the newborn gut leads to mucosal inflammation. Here, we hypothesized that damage-induced production of TLR4 endogenous ligands in the intestine might lead to activation of microglial cells in the brain and promote cognitive impairments. We identified a gut-brain signaling axis in an NEC mouse model in which activation of intestinal TLR4 signaling led to release of high-mobility group box 1 in the intestine that, in turn, promoted microglial activation in the brain and neurological dysfunction. We further demonstrated that an orally administered dendrimer-based nanotherapeutic approach to targeting activated microglia could prevent NEC-associated neurological dysfunction in neonatal mice. These findings shed light on the molecular pathways leading to the development of NEC-associated brain injury, provide a rationale for early removal of diseased intestine in NEC, and indicate the potential of targeted therapies that protect the developing brain in the treatment of NEC in early childhood.

Pulmonary Epithelial TLR4 Activation Leads to Lung Injury in Neonatal Necrotizing Enterocolitis.

We seek to define the mechanisms leading to the development of lung disease in the setting of neonatal necrotizing enterocolitis (NEC), a life-threatening gastrointestinal disease of premature infants characterized by the sudden onset of intestinal necrosis. NEC development in mice requires activation of the LPS receptor TLR4 on the intestinal epithelium, through its effects on modulating epithelial injury and repair. Although NEC-associated lung injury is more severe than the lung injury that occurs in premature infants without NEC, the mechanisms leading to its development remain unknown. In this study, we now show that TLR4 expression in the lung gradually increases during postnatal development, and that mice and humans with NEC-associated lung inflammation express higher levels of pulmonary TLR4 than do age-matched controls. NEC in wild-type newborn mice resulted in significant pulmonary injury that was prevented by deletion of TLR4 from the pulmonary epithelium, indicating a role for pulmonary TLR4 in lung injury development. Mechanistically, intestinal epithelial TLR4 activation induced high-mobility group box 1 release from the intestine, which activated pulmonary epithelial TLR4, leading to the induction of the neutrophil recruiting CXCL5 and the influx of proinflammatory neutrophils to the lung. Strikingly, the aerosolized administration of a novel carbohydrate TLR4 inhibitor prevented CXCL5 upregulation and blocked NEC-induced lung injury in mice. These findings illustrate the critical role of pulmonary TLR4 in the development of NEC-associated lung injury, and they suggest that inhibition of this innate immune receptor in the neonatal lung may prevent this devastating complication of NEC.

Extracorporeal fetal support: a new animal model with preservation of the placenta.

BACKGROUND: Previous models of support for premature sheep fetuses have consisted of cesarean delivery followed by catheterization of umbilical or central vessels and support with extracorporeal membrane oxygenation (ECMO). The limitations of these models have been insufficient blood flow, significant fetal edema, and hemorrhage related to anticoagulation. METHODS: We performed a gravid hysterectomy on 13 ewes between 135 and 145days gestational age. The uterine vessels were cannulated bilaterally and circulatory support was provided via ECMO. Successful transition was defined as maintenance of fetal heart rate for 30minutes after establishing full extracorporeal support. Circuit flow was titrated to maintain mixed venous oxygen saturation (SvO2) of 70-75%. RESULTS: Seven experiments were successfully transitioned to ECMO, with an average survival time of 2hours 9minutes. The longest recorded time from cannulation to death was 6hours 14minutes. By delivering a circuit flow of up to 2120ml/min, all but one of the transitioned uteri were maintained within the desired SvO2 range. CONCLUSION: We report a novel animal model of fetal ECMO support that preserves the placenta, mitigates the effects of heparin, and allows for increased circuit flow compared to prior techniques. This approach may provide insight into a technique for future studies of fetal physiology.

Pressure induced lung injury in a novel in vitro model of the alveolar interface: protective effect of dexamethasone.

PURPOSE: The lungs of infants born with congenital diaphragmatic hernia suffer from immaturity as well as the short and long term consequences of ventilator-induced lung injury, including chronic lung disease. Antenatal and postnatal steroids are among current strategies promoted to treat premature lungs and limit long term morbidity. Although studied in whole-animal models, insight into ventilator-induced injury at the alveolar-capillary interface as well as the benefits of steroids, remains limited. The present study utilizes a multi-fluidic in vitro model of the alveolar-interface to analyze membrane disruption from compressive aerodynamic forces in dexamethasone-treated cultures. METHODS: Human alveolar epithelial cell lines, H441 and A549, were cultured in a custom-built chamber under constant aerodynamic shear followed by introduction of pressure stimuli with and without dexamethasone (0.1µM). On-chip bioelectrical measurements were noted to track changes to the cellular surface and live-dead assay to ascertain cellular viability. RESULTS: Pressure-exposed alveolar cultures demonstrated a significant drop in TEER that was less prominent with an underlying extracellular-matrix coating. Addition of dexamethasone resulted in increased alveolar layer integrity demonstrated by higher TEER values. Furthermore, dexamethasone-treated cells exhibited faster recovery, and the effects of pressure appeared to be mitigated in both cell types. CONCLUSION: Using a novel in vitro model of the alveolus, we demonstrate a dose-response relationship between pressure application and loss of alveolar layer integrity. This effect appears to be alleviated by dexamethasone and matrix sub-coating.

Hydrogen sulfide [corrected] increases survival during sepsis: protective effect of CHOP inhibition.

Sepsis is a major cause of mortality, and dysregulation of the immune response plays a central role in this syndrome. H2S, a recently discovered gaso-transmitter, is endogenously generated by many cell types, regulating a number of physiologic processes and pathophysiologic conditions. We report that H2S increased survival after experimental sepsis induced by cecal ligation and puncture (CLP) in mice. Exogenous H2S decreased the systemic inflammatory response, reduced apoptosis in the spleen, and accelerated bacterial eradication. We found that C/EBP homologous protein 10 (CHOP), a mediator of the endoplasmic reticulum stress response, was elevated in several organs after CLP, and its expression was inhibited by H2S treatment. Using CHOP-knockout (KO) mice, we demonstrated for the first time, to our knowledge, that genetic deletion of Chop increased survival after LPS injection or CLP. CHOP-KO mice displayed diminished splenic caspase-3 activation and apoptosis, decreased cytokine production, and augmented bacterial clearance. Furthermore, septic CHOP-KO mice treated with H2S showed no additive survival benefit compared with septic CHOP-KO mice. Finally, we showed that H2S inhibited CHOP expression in macrophages by a mechanism involving Nrf2 activation. In conclusion, our findings show a protective effect of H2S treatment afforded, at least partially, by inhibition of CHOP expression. The data reveal a major negative role for the transcription factor CHOP in overall survival during sepsis and suggest a new target for clinical intervention, as well potential strategies for treatment.

A multiphase fluidic platform for studying ventilator-induced injury of the pulmonary epithelial barrier.

Mechanical ventilation has been a critical part of basic life support for many years, with almost one-third of all patients in the intensive care unit requiring the aid. However studies over the past two decades have indicated that ventilators have the potential to cause or aggravate pulmonary injury. The lung with its anatomically complex architecture and unique amalgam of cell types and interfaces is very difficult to replicate in vitro. This study is focused on mimicking the distal unit of the alveolus in developing an analytical platform for evaluating cellular interactions and response to mechanostimulation. The prototype developed incorporates the ability to expose alveolar cells to sustained periods of supra-physiological pressure when cultured at an air-liquid interface with constant air-flow on the apical side and medium replenishment on basolateral surfaces. The in vitro evaluation of the alveolar, A549 and H441, cells indicated disruption of the cell layer integrity in response to sustained pressure application. The results indicate a magnitude- and duration-dependent response among both the cell types.

Engineering an artificial alveolar-capillary membrane: a novel continuously perfused model within microchannels.

INTRODUCTION: Pulmonary hypoplasia is a condition of the newborn that is characterized by underdeveloped lungs and poor outcome. One strategy in the treatment of patients with hypoplasia is to augment underdeveloped lungs using biocompatible artificial lung tissue. However, one central challenge in current pulmonary tissue engineering efforts remains the development of a stable bio-mimetic alveolar-capillary membrane. Accordingly, we have built a series of bio-mimetic microfluidic devices that specifically model the alveolar-capillary membrane. Current designs include a single-layer microchip that exposes alveolar and endothelial cell types to controlled fluidic stimuli. A more advanced multi-layered device allows for alveolar cells to be cultured at an air interface while allowing constant media nourishment and waste removal, thus better mimicking the physiologic milieu of the alveolar-capillary interface. Both devices possess the benefit of parallel testing. MATERIAL AND METHODS: Microdevices were fabricated using soft lithography in a biocompatible transparent polymeric material, polydimethyl siloxane, sealed covalently to glass. The multistage microdevice also integrated a suspended polyethylene terephthalate membrane connected via microfluidic channels to constant media and air access. Pulmonary endothelial (HMEC-1) and alveolar epithelial (A549) cell lines, along with fetal pulmonary cells (FPC) harvested from Swiss Webster mice at day 18 gestational age, were studied under multiple hydrodynamic shear conditions and liquid-to-cell ratio regimes. Cultures were examined for cell viability, function and proliferation to confluent monolayers. A549 cells cultured at an air-interface in a microdevice was also tested for their ability to maintain cell phenotype and function. RESULTS: The single-layer differential flow microdevice allowed for a systematic determination of the optimal growth conditions of various lung-specific cell types in a microfluidic environment. Our device showed a greater surfactant based decrease in surface tension of the alveolar hypophase in A549 cultures exposed to air as compared to submerged cultures. CONCLUSIONS: We have successfully developed biomimetic microfluidic devices that specifically allow stable alveolar cell growth at the air-liquid interface. This work serves prerequisite towards an implantable artificial alveolar membrane.

Characterization of pulmonary cell growth parameters in a continuous perfusion microfluidic environment.

In vitro models of the alveolo-pulmonary barrier consist of microvascular endothelial cells and alveolar epithelial cells cultured on opposing sides of synthetic porous membranes. However, these simple models do not reflect the physiological microenvironment of pulmonary cells, wherein cells are exposed to a complex milieu of mechanical and soluble stimuli. In this report, we studied alveolar epithelial (A549) and microvascular endothelial (HMEC-1) cells within varying microfluidic environments as a first step towards building a microfluidic analog of the gas-exchange interface. We fabricated polydimethylsiloxane (PDMS) microdevices for parallel studies of cell growth under multiple flow rates. Cells adhered and proliferated in the microculture chambers for shear stresses up to approximately 2 x 10(-3) dynes/cm(2), corresponding to media turnover rates of approximately 53 seconds. Proliferation of these cells into confluent monolayers and expression of cell-specific markers (SP-A and CD-31) demonstrated successful pulmonary cell culture in microscale devices, a first for alveolar epithelial cells. These results represent the initial steps towards the development of microfluidic analogs of the alveolo-pulmonary barrier and tissue engineering of the lung.

General anesthesia delays the inflammatory response and increases survival for mice with endotoxic shock.

Anesthesia is an indispensable component of any operative procedure. In this study, we demonstrate that continuous isoflurane anesthesia for 1 h after a lethal dose (20 mg/kg of body weight) of Escherichia coli lipopolysaccharide (LPS) results in a significant increase in survival of C57BL/6J (B6) mice in comparison with survival of nonanesthetized mice. Protection by anesthesia correlates with a delay in plasma LPS circulation, resulting in a delayed inflammatory response, particularly DNA binding activity of NF-kappaB and serum levels of tumor necrosis factor alpha, interleukin-6 (IL-6), and IL-10. Disparate classes of anesthetic agents produce the same effects on the inflammatory response, which is also independent of the inbred mouse strain used. These results suggest that anesthesia has an important impact on the outcome from endotoxemia. Moreover, the immunomodulatory effects of anesthetics should be considered when interpreting data from experimental animal models.

Genetic contribution to the septic response in a mouse model.

The response to injury is dependent on several factors, including the type and extent of the injury, genetics, and the environment. In the present study, the genetic contribution to sepsis was evaluated in a mouse model. Sepsis was induced in two inbred mouse strains, C57BL/6J (B6) and A/J, by cecal ligation and single puncture (CLP). Frequency of mortality was significantly higher in B6 than A/J mice from 36 to 132 h after CLP. Plasma TNF-alpha, IL-1beta, and IL-6 levels were similar in both strains after CLP. IL-10 plasma levels were significantly higher in B6 mice as opposed to A/J mice after 24 h of CLP. Similarly, hepatic myeloperoxidase activity, an index of polymorphonuclear leukocytes, was elevated in B6 mice as compared with A/J mice after 24 h of CLP. On the contrary, metallothionein mRNA levels were higher in A/J mice compared with B6 mice. Finally, leptin levels were also higher in A/J than B6 mice within 19 h of CLP. This study demonstrates a genetic contribution in the response to sepsis.