Model Of Systemic Inflammation Research Articles

Iron-Dependent Apoptosis Causes Embryotoxicity in Inflamed and Obese Pregnancy

Since iron is essential for pregnancy, iron supplements are routinely prescribed to pregnant women without screening for iron deficiency. Most women in developed countries have sufficient iron stores, prompting concerns of the potential risks of iron supplementation in iron-replete women. A signal of potential harm of this practice is the association of maternal iron marker ferritin and pregnancy complications. Since ferritin is also induced by inflammation, it is unclear whether iron excess, inflammation, or their interaction cause fetal injury. We used mouse models to address this question. Two mouse models of maternal iron excess were used and compared to mice with normal iron status. To model dietary iron supplementation, C57BL/6 females were fed high-iron diet (2500-5000ppm iron) for 1 week prior to and during pregnancy. To model genetic iron loading, hepcidin knockout females were used and fed standard chow (185ppm iron). Two models of maternal inflammation were used. Acute systemic maternal inflammation was induced by a single subcutaneous injection of LPS on E8.5 or 15.5. Obesity was used as a model of mild chronic systemic maternal inflammation and was induced by feeding female mice Western diet. We evaluated the maternal, placental, and embryo response to iron excess in LPS- and obesity-induced inflammation at various time points. In the model of acute inflammation, we observed an adverse synergistic effect on embryo development when dams were both iron-loaded and LPS-injected, but not with either condition alone. On E8.5, LPS injection in iron-loaded dams caused embryo loss and encephalic malformations (Fig 1a) and on E15.5, LPS injection in iron-loaded dams caused embryo demise and resorption (Fig 1b). Western blotting and immunostaining showed increased apoptotic marker cleaved caspase-3 protein localized to endothelia in placentas and embryos, only when the dam was both iron-loaded and LPS-injected. Cytokine screen in vitro identified TNFα as the signal that synergized with iron to potentiate apoptosis of endothelial cells. Treatment of iron-loaded dams with TNFα-neutralizing antibody protected embryos from LPS-induced death, demonstrating the embryotoxic role of maternal TNFα in iron-loaded dams. Furthermore, RNA-Seq analysis of placental endothelial cells showed enrichment in oxidative stress pathways with maternal iron loading. Treatment of iron-loaded dams with antioxidant α-tocopherol protected against LPS-induced embryo death, attenuated placental inflammation and cleaved caspase-3 expression, and prevented endothelial apoptosis in the placenta and embryo. These data show that iron loading causes endothelial oxidative stress, which sensitizes endothelial cells to inflammation-induced apoptosis. In the obesity model, iron loading worsened embryotoxicity, causing subcutaneous hemorrhaging and eye malformations (Fig 1c), and potentiated placental cleaved caspase-3 expression. Iron loading increased TNFα levels in maternal serum. Importantly, treatment of obese iron-loaded dams with neutralizing TNFα antibody throughout pregnancy reduced the incidence of embryo eye malformations, confirming the role of TNFα in causing embryo injury in iron-loaded obese pregnancy. In summary, maternal iron excess worsened inflammation-induced embryo injury. Iron-dependent embryotoxicity was mediated by TNFα causing lethal apoptotic damage to embryo and placental endothelium which was prevented by antioxidant therapy. Our models raise the possibility that women exposed to both excessive iron and inflammation could be at risk for preventable pregnancy complications. Figure 1. Embryo outcomes in mouse pregnancies with maternal iron loading and inflammation. Figure 1 Disclosures Ganz: Akebia: Consultancy; Vifor: Consultancy; Ionis Pharmaceuticals: Consultancy; Silarus Therapeutics: Current equity holder in private company; Intrinsic LifeSciences: Current equity holder in private company; Global Blood Therapeutics: Consultancy; Ambys: Consultancy; Gossamer Bio: Consultancy; Astellas: Consultancy; Rockwell: Consultancy; Sierra Oncology: Consultancy; Disc Medicine: Consultancy; American Regent: Consultancy. Nemeth:Intrinsic LifeSciences: Current equity holder in private company; Vifor: Consultancy; Protagonist: Consultancy; Silarus Therapeutics: Current equity holder in private company; Ionis Pharmaceuticals: Consultancy.

Human recombinant interleukin-38 suppresses inflammation in mouse models of local and systemic disease

Interleukin (IL)–38 belongs to the IL–1 family and is part of the IL–36 subfamily due to its binding to the IL–36 Receptor (IL–1R6). In the current study, we assessed the anti-inflammatory properties of IL–38 in murine models of arthritis and systemic inflammation. First, the anti-inflammatory properties of mouse and human IL–38 precursors were compared to forms with a truncated N–terminus. In mouse bone marrow derived dendritic cells (BMDC), human and mouse IL–38 precursors with a truncation of the two N-terminal amino acids (3–152) suppressed LPS-induced IL–6. Recombinant human IL–38 (3–152) was further investigated for its immunomodulatory potential using four murine models of inflammatory disease: streptococcal cell wall (SCW)-induced arthritis, monosodium urate (MSU) crystal-induced arthritis, MSU crystal-induced peritonitis, and systemic endotoxemia. In each of these models IL–38 significantly reduced inflammation. In SCW and MSU crystal-induced arthritis, joint swelling, inflammatory cell influx, and synovial levels of IL–1β, IL–6, and KC were reduced by 50% or greater. These suppressive properties of IL–38 in SCW-induced arthritis were independent of the anti-inflammatory co-receptor IL–1R8, as IL–38 reduced arthritis equally in IL–1R8 deficient and WT mice. In MSU crystal-induced peritonitis, IL–38 reduced hypothermia, while plasma IL–6 and KC and peritoneal KC levels were reduced by 65–70%. In the LPS endotoxemia model, IL–38 pretreatment reduced systemic IL–6, TNFα and KC. Furthermore, in ex vivo cultured bone marrow, LPS-induced IL–6, TNFα and KC were reduced by 75–90%. Overall, IL–38 exhibits broad anti-inflammatory properties in models of systemic and local inflammation and therefore may be an effective cytokine therapy.

Impact of Physical Activity and Weight Loss on Fat Mass, Glucose Metabolism, and Inflammation in Older African Americans with Osteoarthritis.

(1) Background: There are currently very few interventions performed within a community setting that compare the effects of physical activity (PA) versus PA plus weight loss on cancer and chronic disease risk in older African Americans. Therefore, we investigated the impact of an 8 week (24 session) PA intervention compared to a PA plus weight loss intervention on fat mass, glucose metabolism, and markers of inflammation in older, overweight and obese African Americans. (2) Methods: Subjects were randomized to a PA (n = 83) or PA plus weight loss (n = 72) intervention that met three times weekly for 8 weeks. At baseline and post-intervention, anthropometrics, body composition, systemic inflammation (high-sensitivity C-reactive protein, tumor necrosis factor-α, and interleukin 6), fasting glucose, insulin and homeostasis model assessment-insulin resistance (HOMA-IR) were determined. (3) Results: Subjects had a mean age of 67 years (SD = 5.3) and were mostly women (88%). The PA plus weight loss group lost more total and visceral fat than the PA group (−4.0% vs. +0.6% and −4.1% vs. +3.7%, respectively, p < 0.01 for both). Changes in inflammation and glucose metabolism were similar between groups post-intervention. Within the PA plus weight loss group only, serum insulin and HOMA-IR decreased significantly. (4) Conclusions: PA combined with weight loss can decrease total and visceral fat mass and improve insulin sensitivity, confirming that these cancer- and chronic disease-related risk factors are influenced by relatively modest lifestyle changes in the short term.

Mesenchymal Stromal Cell‐Mediated Treatment of Local and Systemic Inflammation through the Triggering of an Anti‐Inflammatory Response

AbstractThe emergence of cell‐based therapeutics, specifically the use of mesenchymal stromal/stem cells (MSCs), stands to significantly affect the future of targeted drug delivery technologies. MSCs represent a unique cell type, offering more than only regenerative potential but also site‐specific inflammatory targeting and tissue infiltration. In this study, a versatile multicomponent delivery platform, combining MSC tropism with multistage nanovector (MSV)‐mediated payload delivery, is debuted. It is demonstrated that the incorporation of drug‐loaded MSVs bestows MSCs with the ability to transport anti‐inflammatory payloads, achieving a fivefold increase in payload release without negatively impacting cellular functions, viability, extravasation, and inflammatory homing. When incorporated within MSCs, MSVs avoid rapid sequestration by filtering organs and conserve a 15‐fold increase in local inflammatory targeting compared to healthy ears. Furthermore, this MSC‐mediated MSV platform (M&amp;Ms) rapidly triggers a 4.5‐fold reduction of local inflammation compared to free drug and extends survival to 100% of treated mice in a lethal model of systemic inflammation.

Mice Deficient in NOX2 Display Severe Thymic Atrophy, Lymphopenia, and Reduced Lymphopoiesis in a Zymosan-Induced Model of Systemic Inflammation

Patients with chronic granulomatous disease (CGD) who have mutated phagocyte NADPH oxidase are susceptible to infections due to reduced reactive oxygen species production and exhibit autoimmune and inflammatory diseases in the absence of evident infection. Neutrophils and macrophages have been extensively studied since phagocyte NADPH oxidase is mainly found only in them, while the impact of its deficiency on lymphocyte cellularity is less well characterized. We showed herein a zymosan-induced systemic inflammation model that CGD mice deficient in the phagocyte NADPH oxidase gp91phox subunit (NOX2) exhibited more severe thymic atrophy associated with peripheral blood and splenic lymphopenia and reduced lymphopoiesis in the bone marrow in comparison with the wild-type mice. Conversely, the zymosan-exposed CGD mice suffered from more remarkable neutrophilic lung inflammation, circulating and splenic neutrophilia, and enhanced granulopoiesis compared with those in zymosan-exposed wild-type mice. Overall, this study provided evidence that NOX2 deficiency exhibits severe thymic atrophy and lymphopenia concomitant with enhanced neutrophilic inflammation in a zymosan-induced systemic inflammation model.

Paternal systemic inflammation induces offspring programming of growth and liver regeneration in association with Igf2 upregulation

Recent studies suggest that stress can lead to variations in offspring development. However, whether paternal systemic inflammation induces phenotypic changes in the offspring remains unclear. Here, we established an in vivo mouse model of systemic inflammation and investigated the long-term consequences on the offspring. Male, but not female offspring derived from inflammatory fathers (LPS-F1) grew faster than those derived from the control fathers (CON–F1). Moreover, the LPS-F1 males had higher capacity for liver regeneration after injury, as indicated by decreased hepatic fibrosis, apoptosis, and increased hepatocyte proliferation upon carbon tetrachloride challenge. Insulin-like growth factor 2 (Igf2), a key mitogen that drives growth and liver regeneration, was significantly upregulated in the livers of male, but not female offspring from fathers with inflammation. Taken together, paternal inflammation alters the hepatic Igf2 expression and reprograms growth and liver regeneration in male but not female offspring.

Activation of Cannabinoid Receptor 2 Prevents Colitis-Associated Colon Cancer through Myeloid Cell De-activation Upstream of IL-22 Production.

SummaryIntestinal disequilibrium leads to inflammatory bowel disease (IBD), and chronic inflammation predisposes to oncogenesis. Antigen-presenting dendritic cells (DCs) and macrophages can tip the equilibrium toward tolerance or pathology. Here we show that delta-9-tetrahydrocannabinol (THC) attenuates colitis-associated colon cancer and colitis induced by anti-CD40. Working through cannabinoid receptor 2 (CB2), THC increases CD103 expression on DCs and macrophages and upregulates TGF-β1 to increase T regulatory cells (Tregs). THC-induced Tregs are necessary to remedy systemic IFNγ and TNFα caused by anti-CD40, but CB2-mediated suppression of APCs by THC quenches pathogenic release of IL-22 and IL-17A in the colon. By examining tissues from multiple sites, we confirmed that THC affects DCs, especially in mucosal barrier sites in the colon and lungs, to reduce DC CD86. Using models of colitis and systemic inflammation we show that THC, through CB2, is a potent suppressor of aberrant immune responses by provoking coordination between APCs and Tregs.

Inhibition of the prostaglandin EP2 receptor prevents long-term cognitive impairment in a model of systemic inflammation

Long-term cognitive and affective impairments are common problems in the survivors of sepsis, which weakens their vocational and daily life ability. Neuroinflammation has been reported to exert a key role in the development of cognitive deficit in different disorders including epilepsy, Alzheimer’s disease (AD) and stroke. Mice treated with lipopolysaccharide (LPS), an endotoxin produced by gram-negative bacteria, show a robust but short-lived neuroinflammation and develop long-term memory and affective problems. In this study, we test the hypothesis that pharmacological blockade of the EP2 receptor for prostaglandin E2 reduces neuroinflammation and prevents long-term affective and memory deficits in a mouse model of LPS-induced, sepsis-associated encephalopathy (SAE). Our results show that an EP2 antagonist, TG6-10-1, promotes the recovery of body weight, mitigates neuroinflammation as judged by inflammatory cytokines and microgliosis, prevents the loss of synaptic proteins, and ameliorates depression-like behavior in the sucrose preference test as well as memory loss in the novel object recognition test. Our results point to a new avenue to ameliorate neuroinflammation and long-term affective and cognition problems of sepsis survivors.

Application and Efficacy of Vitamin E-Bonded Polysulfone Membrane in Acute Blood Purification Therapy

Introduction: Acute blood purification therapy (BPT) has been evaluated in the context of intensive care for serious conditions related to systemic inflammation, but its mechanism and efficacy are not fully understood. Objective: This study examined the feasibility of using vitamin E-bonded polysulfone membranes (VEPS) for BPT in a LPS-induced rat model of systemic inflammation. Methods: To evaluate the efficacy of BPT with a VEPS membrane, polysulfone (PS) membranes conventionally used in intensive care were bonded with the antioxidant vitamin E and used in a rat model of lipopolysaccharide (LPS)-induced systemic inflammation. BPT using a PS membrane (PS group) or a VEPS membrane (VEPS group) was performed 6 h after administration of LPS. Extracorporeal circulation was established in normal rats as a control (sham group). Survival rates, histology of lung specimens, and levels of myeloperoxidase (MPO) and high mobility group box-1 (HMGB-1) were examined in each group. Results: Survival rates at 24 h after LPS administration were 100% in the VEPS group and 50% in the PS group. Pulmonary architecture was largely maintained and the level of infiltration of inflammatory cells remained moderate in the VEPS group. Levels of active MPO before and after BPT were significantly higher in the PS and VEPS groups than in the sham group, with no significant differences between the PS and VEPS groups. HMGB-1 levels were significantly elevated after BPT in the PS group. Conclusions: This study demonstrated that use of the VEPS membrane for BPT increased survival rate and reduced lung injury in a rat model of systemic inflammatory response syndrome (SIRS), suggesting the possible use of VEPS membranes in the treatment of serious conditions related to systemic inflammation.

Overview: Systemic Inflammatory Response Derived From Lung Injury Caused by SARS-CoV-2 Infection Explains Severe Outcomes in COVID-19.

Most SARS-CoV2 infections will not develop into severe COVID-19. However, in some patients, lung infection leads to the activation of alveolar macrophages and lung epithelial cells that will release proinflammatory cytokines. IL-6, TNF, and IL-1β increase expression of cell adhesion molecules (CAMs) and VEGF, thereby increasing permeability of the lung endothelium and reducing barrier protection, allowing viral dissemination and infiltration of neutrophils and inflammatory monocytes. In the blood, these cytokines will stimulate the bone marrow to produce and release immature granulocytes, that return to the lung and further increase inflammation, leading to acute respiratory distress syndrome (ARDS). This lung-systemic loop leads to cytokine storm syndrome (CSS). Concurrently, the acute phase response increases the production of platelets, fibrinogen and other pro-thrombotic factors. Systemic decrease in ACE2 function impacts the Renin-Angiotensin-Kallikrein-Kinin systems (RAS-KKS) increasing clotting. The combination of acute lung injury with RAS-KKS unbalance is herein called COVID-19 Associated Lung Injury (CALI). This conservative two-hit model of systemic inflammation due to the lung injury allows new intervention windows and is more consistent with the current knowledge.

Elucidating vulnerability to inflammation-induced hyperalgesia: Predictors of increased musculoskeletal pain sensitivity during experimental endotoxemia

Despite broad clinical implications, the mechanisms linking inflammation and pain remain incompletely understood. Using human experimental endotoxemia as a translational model of systemic inflammation, we aimed to elucidate putative vulnerability factors of inflammation-induced musculoskeletal hyperalgesia.We pooled data from three published randomized controlled trials, resulting in a sample of N = 98 healthy volunteers who received either low-dose endotoxin (lipopolysaccharide) or vehicle (saline) intravenously. As measure of musculoskeletal pain sensitivity, pressure pain thresholds (PPTs) were assessed at baseline and 3 h post injection with a handheld algometer for the low back (erector spinae muscle), calf (gastrocnemius muscle), and shoulder region (deltoid muscle). Implementing multiple regression models, we tested the contribution of putative vulnerability factors on musculoskeletal hyperalgesia during systemic inflammation, including acute changes in pro-inflammatory cytokines, state anxiety and mood, as well as pre-existing symptoms of anxiety and depression.Endotoxin application led to significant increases in plasma cytokines, state anxiety, and negative mood, and significantly decreased PPTs for all muscle groups. Regression models revealed that greater M. erector spinae PPT changes were predicted by higher HADS-anxiety scores. Higher TNF-α concentration emerged as predictor for M. gastrocnemius PPT changes, and more pronounced TNF-α increase and higher HADS-anxiety were predictive for M. deltoideus PPTs. HADS scores emerged as predictor for a mean PPT score (computed across all body sites).Together, our results indicate that musculoskeletal hyperalgesia during systemic inflammation is related to pro-inflammatory cytokines, specifically TNF-α. Importantly, subclinical anxiety symptoms (even though in a low and normal range in this cohort of healthy volunteers) may contribute to inflammation-induced hyperalgesia, making individuals more vulnerable to the detrimental effects of systemic inflammation.

Cardiorespiratory Alterations in a Newborn Ovine Model of Systemic Inflammation Induced by Lipopolysaccharide Injection.

Although it is well known that neonatal sepsis can induce important alterations in cardiorespiratory control, their detailed early features and the mechanisms involved remain poorly understood. As a first step in resolving this issue, the main goal of this study was to characterize these alterations more extensively by setting up a full-term newborn lamb model of systemic inflammation using lipopolysaccharide (LPS) injection. Two 6-h polysomnographic recordings were performed on two consecutive days on eight full-term lambs: the first after an IV saline injection (control condition, CTRL); the second, after an IV injection of 2.5 μg/kg Escherichia coli LPS 0127:B8 (LPS condition). Rectal temperature, locomotor activity, state of alertness, arterial blood gases, respiratory frequency and heart rate, mean arterial blood pressure, apneas and cardiac decelerations, and heart-rate and respiratory-rate variability (HRV and RRV) were assessed. LPS injection decreased locomotor activity (p = 0.03) and active wakefulness (p = 0.01) compared to the CTRL. In addition, LPS injection led to a biphasic increase in rectal temperature (p = 0.01 at ∼30 and 180 min) and in respiratory frequency and heart rate (p = 0.0005 and 0.005, respectively), and to an increase in cardiac decelerations (p = 0.05). An overall decrease in HRV and RRV was also observed. Interestingly, the novel analysis of the representations of the horizontal and vertical visibility network yielded the most statistically significant alterations in HRV structure, suggesting its potential clinical importance for providing an earlier diagnosis of neonatal bacterial sepsis. A second goal was to assess whether the reflexivity of the autonomic nervous system was altered after LPS injection by studying the cardiorespiratory components of the laryngeal and pulmonary chemoreflexes. No difference was found. Lastly, preliminary results provide proof of principle that brainstem inflammation (increased IL-8 and TNF-α mRNA expression) can be shown 6 h after LPS injection. In conclusion, this full-term lamb model of systemic inflammation reproduces several important aspects of neonatal bacterial sepsis and paves the way for studies in preterm lambs aiming to assess both the effect of prematurity and the central neural mechanisms of cardiorespiratory control alterations observed during neonatal sepsis.

Iron Chelation in Murine Models of Systemic Inflammation Induced by Gram-Positive and Gram-Negative Toxins

Iron is an essential element for various physiological processes, but its levels must remain tightly regulated to avoid cellular damage. Similarly, iron plays a dual role in systemic inflammation, such as with sepsis. Leukocytes utilize iron to produce reactive oxygen species (ROS) to kill bacteria, but pathologically increased iron-catalyzed ROS production in sepsis can lead to damage of host cells, multi-organ failure and death. Temporary reduction in bioavailable iron represents a potential therapeutic target in sepsis. This study investigates the effect of the novel iron chelator, DIBI, in murine models of systemic (hyper-)inflammation: C57BL/6 mice were challenged with toxins from Gram-positive (Staphylococcus aureus: lipoteichoic acid, peptidoglycan) and Gram-negative bacteria (Escherichia coli and Klebsiella pneumoniae: lipopolysaccharide). Intravital microscopy (IVM) was performed to assess immune cell activation and its impact on microvascular blood flow in vivo in the microcirculation of the gut. Plasma inflammatory mediators were measured via multiplex assay, and morphologic change in intestinal tissue was evaluated. DIBI treatment decreased leukocyte (hyper-)activation induced by Gram-positive and Gram-negative toxins. In some cases, it preserved capillary perfusion, reduced plasma inflammatory markers and attenuated tissue damage. These findings support the utility of DIBI as a novel treatment for systemic inflammation, e.g., sepsis.

Therapeutic effects of IkB kinase inhibitor during systemic inflammation

Animal models of inflammatory diseases support the idea that nuclear factor κB (NF-κB) activation plays a pathophysiological role and is widely implicated in multiple organ dysfunction (MOD). Indeed, the inhibition of the IκB kinase (IKK) complex, involved in the NF-κB pathway, can represent a promising approach to prevent MOD. The present work employed a rat model of systemic inflammation to investigate the preventive effects of Inhibitor of IKK complex (IKK16).In male Wistar rats, systemic inflammation was induced by a tail vein injection of lipopolysaccharides (LPS challenge; 12 mg/kg). Treatment with IKK16 (1 mg/kg body weight) was administered, by tail vein, 15 min post-LPS. Age- and sex-matched healthy rats and LPS rats without treatment were used as controls. At 24 h post-IKK16 treatment, serum enzyme levels indicative of liver, kidney, pancreas and muscle function were evaluated by biochemical analysis, and RT-PCR technique was used to analyze gene expression of pro-inflammatory cytokines. Hemodynamic parameters were also considered to assess the LPS-induced inflammation.IKK16 treatment yielded a strong therapeutic effect in preventing LPS-induced elevation of serological enzyme levels, attenuating hepatic, renal, pancreatic and muscular dysfunction after LPS challenge. Moreover, as expected, LPS promoted a significantly overexpression of TNF-α, IL-6 and IL-1β in the heart, kidney, and liver; which was diminished by IKK16 treatment.The present study provides convincing evidence that selective inhibition of the IκB kinase complex through the action of IKK16, plays a protective role against LPS-induced multiple organ dysfunction by reducing the acute inflammatory response induced by endotoxin exposure.

Vitamin D3 attenuates lipopolysaccharide-induced cognitive impairment in rats by inhibiting inflammation and oxidative stress

AimsVitamin D is a well-known endocrine regulator of calcium/phosphate homeostasis and has been reported as having a wide range of activities that are potentially beneficial for human health. This study aimed to investigate the effects of pretreatment of vitamin D3 (100, 1000, and 10,000 IU/kg) against lipopolysaccharide (LPS)-induced cognitive impairment in rats. Main methodsMale Wistar rats were divided into five groups. The passive avoidance test and Morris water maze (MWM) test were conducted to evaluate the learning and memory function. Oxidative stress markers including malondialdehyde (MDA), catalase (CAT), superoxide dismutase (SOD), total thiol content as well as interleukin (IL)-6 were evaluated in the hippocampus tissue. Key findingsThe intraperitoneal (i.p.) injection of LPS (1 mg/kg) correlates with deficits in passive avoidance and spatial learning in the systemic inflammation model. However, pretreatment with vitamin D3 improved LPS-induced cognitive impairment. In addition, vitamin D3 decreased IL-6 and MDA levels, whereas the activities of CAT, SOD, and total thiol content in the hippocampus tissue were significantly increased. SignificanceIn conclusion, our results suggest that vitamin D3 plays a protective role against memory dysfunction caused by LPS-induced inflammation through inhibition of oxidative stress and inflammation in the hippocampus. Vitamin D may be a promising potential therapeutic supplement for the treatment or prevention of learning and memory disorders.

The Reflex Sympathetic Activation Attenuates Systemic Inflammation in Unanesthetized Rats

The literature reports that electrical activation or surgical denervation of the sympathetic nerves elicits anti‐inflammatory effects. Our previous study (American Heart Association’s Council on Hypertension 2016 Scientific Sessions: AP305) also indicated that sympathetic activation, by bilateral carotid occlusion (BCO) in unanesthetized rats, attenuates the release of pro‐inflammatory cytokines in an experimental model of sepsis. However, to expand the knowledge about the anti‐inflammatory potential of this arm of the autonomic nervous system, the objective of the present study was to investigate the role of global reflex sympathetic activation by BCO in a systemic inflammation induced by a low dose of lipopolysaccharide (LPS). For this, femoral artery and vein catheters were inserted into anesthetized Wistar Hannover male rats, for arterial pressure recording and LPS administration, respectively. Moreover, the subjects were implanted with pneumatic cuffs around the common carotid arteries for performing the BCO. On the next day, under unanesthetized rats, the arterial pressure was recorded continuously during 7 hours, including the baseline period. After baseline parameters recording, the BCO was performed for 20 s; and immediately after, LPS (60 μg/kg, i.v.) or saline was administrated. Blood samples were collected under different moments (90, 180, 270 and 360 min), after LPS or saline injection, for analyzing plasma cytokines (TNF, IL‐6, IL‐1β, and IL‐10) levels over time. As expected, BCO was effective to increase the arterial pressure, confirming the reflex sympathetic activation. Over time, no difference was observed among all groups concerning the arterial pressure; however, the groups which received LPS showed an increase in heart rate at 180, 270 and 360 min, compared with the saline group. However, the BCO did not change this response. Concerning the plasma cytokine levels, 90 min after LPS, BCO attenuated TNF and IL‐1β levels, as compared to LPS treated rats [TNF: 1831 ± 290 (n = 8) vs. 1326 ± 180 pg/mL (n = 8); IL‐1β: 212 ± 74 (n = 8) vs. 104 ± 39 pg/mL, (n = 8)]. BCO also increased the IL‐10 levels at 90 min [410 ± 55 (n = 8) vs. 730 ± 66 pg/mL (n = 8)]. Nevertheless, BCO did not change IL‐6 levels [IL‐6: 8389 ± 1480 (n = 8) vs. 8546 ± 1560 pg/mL (n = 8)]. No differences in plasma cytokine levels were observed at 180, 270 or 360 min after LPS, comparing the LPS group with the LPS+BCO group. In conclusion, these results suggest that the reflex sympathetic activation, in unanesthetized rats, attenuates plasma pro‐inflammatory cytokines and increase the anti‐inflammatory cytokine release in a model of systemic inflammation. These data provide support to previous evidence concerning the anti‐inflammatory effects of the sympathetic arm of the autonomic nervous system.Support or Funding InformationFAPESP (2017/05163‐6; 2013/20549‐7) and CNPq (402076/2016‐8).

Effect of Vasopressors on the Macro- and Microcirculation During Systemic Inflammation in Humans In Vivo

Comparing the effects of different vasopressors in septic shock patients is hampered by high heterogeneity and the fact that current guidelines dictate the use of norepinephrine. Herein, we studied the effects of three vasopressor agents, norepinephrine, phenylephrine, and vasopressin, on the macro- and microcirculation during experimental human endotoxemia, a standardized, controlled model of systemic inflammation in humans in vivo. We performed a randomized controlled study in which 40 healthy male volunteers were assigned to a 5-h infusion of either 0.05 μg/kg/min norepinephrine (n = 10), 0.5 μg/kg/min phenylephrine (n = 10), 0.04 IU/min vasopressin (n = 10), or saline (n = 10), starting 1 h before intravenous administration of 2 ng/kg lipopolysaccharide (LPS). The macrocirculation was monitored using arterial catheter-derived parameters with additional blood pressure waveform contour analysis (PCA) until 4.5 h following LPS administration. Sublingual microcirculatory density and flow were assessed using a handheld video microscope until 6 h post-LPS. LPS administration affected all macrocirculatory and microcirculatory parameters. The LPS-induced decrease in blood pressure and systemic vascular resistance (SVR) was refractory to low-dose norepinephrine and phenylephrine, and to a lesser extent, to vasopressin. Only vasopressin exerted effects on PCA parameters compared with placebo, by mitigating the LPS-induced decrease in diastolic blood pressure by stabilizing SVR and cardiac output. The endotoxemia-induced decreased indices of microvascular flow and density were not influenced by vasopressor therapy. In a highly controlled model of systemic inflammation in humans in vivo, a 5-h infusion of various vasopressors revealed distinctive effects on macrohemodynamic variables without affecting the sublingual microcirculation.

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In This Issue

Chronic Systemic Inflammation Exacerbates Neurotoxicity in a Parkinson's Disease Model.

Systemic inflammation is a crucial factor for microglial activation and neuroinflammation in neurodegeneration. This work is aimed at assessing whether previous exposure to systemic inflammation potentiates neurotoxic damage by the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and how chronic systemic inflammation participates in the physiopathological mechanisms of Parkinson's disease. Two different models of systemic inflammation were employed to explore this hypothesis: a single administration of lipopolysaccharide (sLPS; 5 mg/kg) and chronic exposure to low doses (mLPS; 100 μg/kg twice a week for three months). After three months, both groups were challenged with MPTP. With the sLPS administration, Iba1 staining increased in the striatum and substantia nigra, and the cell viability lowered in the striatum of these mice. mLPS alone had more impact on the proinflammatory profile of the brain, steadily increasing TNFα levels, activating microglia, reducing BDNF, cell viability, and dopamine levels, leading to a damage profile similar to the MPTP model per se. Interestingly, mLPS increased MAO-B activity possibly conferring susceptibility to MPTP damage. mLPS, along with MPTP administration, exacerbated the neurotoxic effect. This effect seemed to be coordinated by microglia since minocycline administration prevented brain TNFα increase. Coadministration of sLPS with MPTP only facilitated damage induced by MPTP without significant change in the inflammatory profile. These results indicate that chronic systemic inflammation increased susceptibility to MPTP toxic effect and is an adequate model for studying the impact of systemic inflammation in Parkinson's disease.

Y-RNA subtype ratios in plasma extracellular vesicles are cell type- specific and are candidate biomarkers for inflammatory diseases

ABSTRACT Major efforts are made to characterize the presence of microRNA (miRNA) and messenger RNA in blood plasma to discover novel disease-associated biomarkers. MiRNAs in plasma are associated to several types of macromolecular structures, including extracellular vesicles (EV), lipoprotein particles (LPP) and ribonucleoprotein particles (RNP). RNAs in these complexes are recovered at variable efficiency by commonly used EV- and RNA isolation methods, which causes biases and inconsistencies in miRNA quantitation. Besides miRNAs, various other non-coding RNA species are contained in EV and present within the pool of plasma extracellular RNA. Members of the Y-RNA family have been detected in EV from various cell types and are among the most abundant non-coding RNA types in plasma. We previously showed that shuttling of full-length Y-RNA into EV released by immune cells is modulated by microbial stimulation. This indicated that Y-RNAs could contribute to the functional properties of EV in immune cell communication and that EV-associated Y-RNAs could have biomarker potential in immune-related diseases. Here, we investigated which macromolecular structures in plasma contain full length Y-RNA and whether the levels of three Y-RNA subtypes in plasma (Y1, Y3 and Y4) change during systemic inflammation. Our data indicate that the majority of full length Y-RNA in plasma is stably associated to EV. Moreover, we discovered that EV from different blood-related cell types contain cell-type-specific Y-RNA subtype ratios. Using a human model for systemic inflammation, we show that the neutrophil-specific Y4/Y3 ratios and PBMC-specific Y3/Y1 ratios were significantly altered after induction of inflammation. The plasma Y-RNA ratios strongly correlated with the number and type of immune cells during systemic inflammation. Cell-type-specific “Y-RNA signatures” in plasma EV can be determined without prior enrichment for EV, and may be further explored as simple and fast test for diagnosis of inflammatory responses or other immune-related diseases.