Therapeutic Potential of NOS Inhibitors in Septic Shock

SummaryTreatment of hemodynamic instability in septic shock often demands the administration of vasopressor agents, although these may have deleterious effects on microcirculatory homeostasis. Inhibition of nitric oxide synthase (NOS) has been suggested as an alternative therapeutic approach, as NO formation may be excessively increased in sepsis. To compare the effects of epinephrine titration, non-selective NOS inhibition by L-NMMA and selective inhibition of inducible NOS (iNOS) by 1400W on hemodynamics and on the regulation of microcirculation in a rat model of endotoxic shock, we intravenously injected endotoxin (LPS) or saline to male Wist ar rats and after 2 hours randomized LPS treated rats into four different groups that received either saline, norepinephrine, L-NMMA or 1400W (n=6 per group). Three hours after LPS administration, rats presented with severe systemic arterial hypotension (64 ± 3 vs. 115 ± 4 mmHg, p<0.001), unresponsiveness to volume treatment, lactate acidosis and a marked increase in plasmatic nitrite and nitrate levels (15 ±8 vs. 263 ± 47 µM, p<0.001). Measurement of the tissue oxygenation in the ileum mucosal layer by the Erlangen micro-lightguide spectrophotometer (EMPHO) technique demonstrated marked heterogeneity of hemoglobin saturation, with appearance of low oxygenated areas. Norepinephrine, usually stabilizing blood pressure (99 ±7 vs. 67 ±4 mmHg 60 min after infusion, p<0.01), increased lactate formation (7.9± 0.2 vs. 3.7 ± 0.5 mM, p<0.001) and drastically increased low oxygenated regions in the ileum mucosal layer. L-NMMA similarly increased blood pressure (92 ±6 vs. 67 ±4 mmHg 60 min after infusion, p<0.05), but did not enhance lactate acidosis. However, some further deterioration of mucosa oxygenation was again noted. 1400W forwarded stabilization of blood pressure (88 ± 5 vs. 67 ±4 mmHg 60 min after injection, p<0.05), reduced plasmatic nitrite and nitrate levels similar to L-NMMA, without an aggravation of lactate acidosis. In addition, mucosal oxygenation did not deteriorate in response to this agent. Thereby, we conclude that in a rat model of endotoxic shock selective iNOS inhibitors are superior to non-specific NOS inhibitors and in particular to norepinephrine for the treatment of macro-and microcirculatory abnormalities in experimental septic shock.

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The Trend of β3-Adrenergic Receptor in the Development of Septic Myocardial Depression: A Lipopolysaccharide-Induced Rat Septic Shock Model

Cardiology ◽

10.1159/000487126 ◽

2018 ◽

Vol 139 (4) ◽

pp. 234-244 ◽

Cited By ~ 7

Author(s):

Ni Yang ◽

Xiao-Lu Shi ◽

Bing-Lun Zhang ◽

Jian Rong ◽

Tie-Ning Zhang ◽

...

Keyword(s):

Septic Shock ◽

Left Ventricular ◽

Neonatal Rat ◽

Myocardial Depression ◽

Rat Cardiomyocytes ◽

Neonatal Cardiomyocytes ◽

Nos Inhibitors ◽

Lps Treatment

Septic shock with low cardiac output is very common in children. However, the mechanism underlying myocardial depression is unclear. The role of β3-AR in the development of myocardial depression in sepsis is unknown. In the present study, we generated an adolescent rat model of hypodynamic septic shock induced by lipopolysaccharide (LPS). Neonatal cardiomyocytes were also treated with LPS to mimic myocardial depression in sepsis, which was confirmed via an in vivo left ventricular hemodynamic study, and measurements of contractility and the Ca2+ transient in isolated adolescent and neonatal cardiomyocytes. After 16 h of LPS treatment, cultured neonatal cardiomyocytes showed a diminished Ca2+ transient amplitude associated with an increase in the β3-AR level. With the addition of a β3-AR agonist, the Ca2+ transient in LPS-treated neonatal rat cardiomyocytes gradually decreased over time; such a change was absent in cells treated with nitric oxide synthase (NOS) inhibitors prior to treatment with a β3-AR agonist. In adolescent rats with septic myocardial depression, cardiac function declined as indicated by decreased MAP, dP/dtmax, and dP/dtmix for 6 h after LPS injection; however, the β3-AR level first increased 2 h after LPS treatment and then decreased 6 h after LPS treatment in the absence of exogenous catecholamines. The results indicate that, in vitro, at the cellular level β3-AR may be involved in the development of myocardial depression (Ca2+ transient depression) in sepsis through NOS signaling pathways; however, in vivo, a complicated mechanism for modulating β3-AR may exist.

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Apelin-13 in septic shock: effective in supporting hemodynamics in sheep but compromised by enzymatic breakdown in patients

Scientific Reports ◽

10.1038/s41598-021-02087-4 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

David Coquerel ◽

Julie Lamoureux ◽

Frédéric Chagnon ◽

Kien Trân ◽

Michael Sage ◽

...

Keyword(s):

Septic Shock ◽

Time Course ◽

Therapeutic Potential ◽

Systemic Infection ◽

Early Time ◽

Large Animal ◽

Human Sepsis ◽

Enzymatic Systems ◽

Threatening Condition ◽

Organ Failures

AbstractSepsis is a prevalent life-threatening condition related to a systemic infection, and with unresolved issues including refractory septic shock and organ failures. Endogenously released catecholamines are often inefficient to maintain blood pressure, and low reactivity to exogenous catecholamines with risk of sympathetic overstimulation is well documented in septic shock. In this context, apelinergics are efficient and safe inotrope and vasoregulator in rodents. However, their utility in a larger animal model as well as the limitations with regards to the enzymatic breakdown during sepsis, need to be investigated. The therapeutic potential and degradation of apelinergics in sepsis were tested experimentally and in a cohort of patients. (1) 36 sheep with or without fecal peritonitis-induced septic shock (a large animal experimental design aimed to mimic the human septic shock paradigm) were evaluated for hemodynamic and renal responsiveness to incremental doses of two dominant apelinergics: apelin-13 (APLN-13) or Elabela (ELA), and (2) 52 subjects (33 patients with sepsis/septic shock and 19 healthy volunteers) were investigated for early levels of endogenous apelinergics in the blood, the related enzymatic degradation profile, and data regarding sepsis outcome. APLN-13 was the only one apelinergic which efficiently improved hemodynamics in both healthy and septic sheep. Endogenous apelinergic levels early rose, and specific enzymatic breakdown activities potentially threatened endogenous apelin system reactivity and negatively impacted the outcome in human sepsis. Short-term exogenous APLN-13 infusion is helpful in stabilizing cardiorenal functions in ovine septic shock; however, this ability might be impaired by specific enzymatic systems triggered during the early time course of human sepsis. Strategies to improve resistance of APLN-13 to degradation and/or to overcome sepsis-induced enzymatic breakdown environment should guide future works.

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Immunoneutralization of the aminoprocalcitonin peptide of procalcitonin protects rats from lethal endotoxaemia: neuroendocrine and systemic studies

Clinical Science ◽

10.1042/cs20100007 ◽

2010 ◽

Vol 119 (12) ◽

pp. 519-534 ◽

Cited By ~ 23

Author(s):

Eva Tavares ◽

Francisco J. Miñano

Keyword(s):

Septic Shock ◽

Amino Acid ◽

Therapeutic Potential ◽

Shock Therapy ◽

Inflammatory Factor ◽

Central Administration ◽

Term Survival ◽

Mortality And Morbidity ◽

Il Interleukin ◽

Tnf Α

Severe sepsis and septic shock are an important cause of mortality and morbidity. These illnesses can be triggered by the bacterial endotoxin LPS (lipopolysaccharide) and pro-inflammatory cytokines, particularly TNF-α (tumour necrosis factor-α) and IL (interleukin)-1β. Severity and mortality of sepsis have also been associated with high concentrations of N-PCT (aminoprocalcitonin), a 57-amino-acid neuroendocrine peptide derived from ProCT (procalcitonin). Previous studies in a lethal model of porcine polymicrobial sepsis have revealed that immunoneutralization with IgG that is reactive to porcine N-PCT significantly improves short-term survival. To explore further the pathophysiological role of N-PCT in sepsis, we developed an antibody raised against a highly conserved amino acid sequence of human N-PCT [N-PCT-(44–57)]. This sequence differs by only one amino acid from rat N-PCT. First, we demonstrated the specificity of this antibody in a well-proven model of anorexia induced in rats by central administration of human N-PCT-(1–57). Next we explored further the therapeutic potential of anti-N-PCT-(44–57) in a rat model of lethal endotoxaemia and determined how this immunoneutralization affected LPS-induced lethality and cytokine production. We show that this specific antibody inhibited the LPS-induced early release of TNF-α and IL-1β and increased survival, even if treatment began after the cytokine response had occurred. In addition, anti-N-PCT-(44–57) may increase long-term survival in LPS-treated rats by up-regulating the late production of counter-regulatory anti-inflammatory mediators such as ACTH (adrenocorticotropic hormone) and IL-10. In conclusion, these results support N-PCT as a pro-inflammatory factor in both the early and the late stages of lethal endotoxaemia, and suggest anti-N-PCT as a candidate for septic shock therapy.

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Effects of dexamethasone and l-canavanine on the intracellular calcium-contraction relation of the rat tail artery during septic shock

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00997.2005 ◽

2006 ◽

Vol 291 (3) ◽

pp. H1177-H1182 ◽

Cited By ~ 10

Author(s):

Arnaud Mansart ◽

Pierre-Edouard Bollaert ◽

Philippe Giummelly ◽

Christine Capdeville-Atkinson ◽

Jeffrey Atkinson

Keyword(s):

Septic Shock ◽

Vascular Reactivity ◽

Perfusion Pressure ◽

Cecal Ligation ◽

Rat Tail Artery ◽

Tail Artery ◽

Nos Inhibitors ◽

Intracellular Ca ◽

Rat Tail ◽

Inducible Nos

The intracellular mechanism by which sepsis lowers vascular reactivity and the subsequent reversal by dexamethasone or nitric oxide synthase (NOS) inhibitors remain unclear. We measured the sensitivity of contraction of the rat tail artery to intracellular Ca2+ in a model of polymicrobial septic shock. At 22 h after cecal ligation and puncture (CLP), rats were treated with an anti-inflammatory glucocorticoid (dexamethasone, 1 mg/kg ip), an inducible NOS inhibitor (l-canavanine, 100 mg/kg ip), or saline. At 24 h after CLP, endothelium-denuded, perfused segments of tail artery were loaded with the intracellular Ca2+-sensitive dye fura 2 in vitro. Intracellular Ca2+ concentration and perfusion pressure were measured simultaneously. The rightward shift of the perfusion pressure-intracellular Ca2+ mobilization curve after norepinephrine stimulation subsequent to CLP indicates decreased intracellular Ca2+ sensitivity of contraction. The relation was restored by dexamethasone (which also restored in vivo blood pressure and flow), but not by l-canavanine (which restored perfusion pressure by further mobilization of intracellular Ca2+). We conclude that CLP lowers vasomotion by lowering intracellular Ca2+ sensitivity, which can be restored with glucocorticoid treatment. The involvement of inducible NOS does not solely account for the sepsis-induced reduction in Ca2+ sensitivity of contraction.

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Arginine-Based Inhibitors of Nitric Oxide Synthase: Therapeutic Potential and Challenges

Mediators of Inflammation ◽

10.1155/2012/318087 ◽

2012 ◽

Vol 2012 ◽

pp. 1-22 ◽

Cited By ~ 90

Author(s):

Jan Víteček ◽

Antonín Lojek ◽

Giuseppe Valacchi ◽

Lukáš Kubala

Keyword(s):

Nitric Oxide ◽

Drug Design ◽

Therapeutic Potential ◽

Structural Characteristics ◽

Biochemical Properties ◽

Modern Drug ◽

Nos Inhibitors ◽

Specific Inhibitors

In the past three decades, nitric oxide has been well established as an important bioactive molecule implicated in regulation of cardiovascular, nervous, and immune systems. Therefore, it is not surprising that much effort has been made to find specific inhibitors of nitric oxide synthases (NOS), the enzymes responsible for production of nitric oxide. Among the many NOS inhibitors developed to date, inhibitors based on derivatives and analogues of arginine are of special interest, as this category includes a relatively high number of compounds with good potential for experimental as well as clinical application. Though this group of inhibitors covers early nonspecific compounds, modern drug design strategies such as biochemical screening and computer-aided drug design have provided NOS-isoform-specific inhibitors. With an emphasis on major advances in this field, a comprehensive list of inhibitors based on their structural characteristics is discussed in this paper. We provide a summary of their biochemical properties as well as their observed effects bothin vitroandin vivo. Furthermore, we focus in particular on their pharmacology and use in recent clinical studies. The potential of newly designed specific NOS inhibitors developed by means of modern drug development strategies is highlighted.

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NAD+ prevents septic shock by non-canonical inflammasome blockade and IL-10

10.1101/2020.03.29.013649 ◽

2020 ◽

Author(s):

Jasper Iske ◽

Rachid El Fatimy ◽

Yeqi Nian ◽

Siawosh K. Eskandari ◽

Hector Rodriguez Cetina Biefer ◽

...

Keyword(s):

Septic Shock ◽

Signaling Pathway ◽

Inflammatory Cytokine ◽

Cytokine Production ◽

Therapeutic Potential ◽

Endotoxic Shock ◽

Immune Homeostasis ◽

Inflammasome Activation ◽

Specific Inhibition ◽

Inflammatory Cytokine Production

AbstractNon-canonical inflammasome activation is crucial in the development of septic shock promoting pyroptosis and pro-inflammatory cytokine production via caspase-11 and Gasdermin-D (GSDMD). Here, we show that NAD+ treatment protected mice towards bacterial and LPS induced endotoxic shock by blocking the non-canonical inflammasome specifically. NAD+ administration impeded systemic IL-1β and IL-18 production and GSDMD-mediated pyroptosis of macrophages via the IFN-β/STAT-1 signaling machinery. More importantly, NAD+ administration not only improved casp-11-/- survival but rendered WT mice completely resistant to septic shock via the IL-10 signaling pathway that was independent from the non-canonical inflammasome. Here, we delineated a two-sided effect of NAD+ blocking septic shock through a specific inhibition of the non-canonical inflammasome and promoting immune homeostasis via IL-10, underscoring its unique therapeutic potential.SummaryNAD+ protects against septic shock by blocking the non-canonical inflammasome specifically and via a systemic production of IL-10 cytokine

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Chronic Critically Ill Septic Patients Exhibit Persistent Expression of Pro-Inflammatory Lipidomics

Current Developments in Nutrition ◽

10.1093/cdn/nzaa055_004 ◽

2020 ◽

Vol 4 (Supplement_2) ◽

pp. 1119-1119

Author(s):

J Christian Brown ◽

Stacey Kirkpatrick ◽

Dijoia Darden ◽

Tyler Loftus ◽

Amir Kamel ◽

...

Keyword(s):

Septic Shock ◽

Severe Sepsis ◽

Patient Population ◽

Therapeutic Potential ◽

Low Grade ◽

Omega 3 ◽

University Of Florida ◽

Funding Sources ◽

Persistent Inflammation ◽

Sepsis Survivors

Abstract Objectives In order to evaluate the therapeutic potential of resolvins to reduce inflammation in CCI-PICS, we recapitulated Glue Grant leukotriene and resolvin lipidomic scores above to quantify lipidomics in severe sepsis/septic shock survivors. Methods Ongoing University of Florida (UF) Sepsis Critical Illness Research Center (SCIRC) research studies indicate that Persistent Inflammation, Immunosuppression, and Catabolism Syndrome (PICS) occurs as a result of a self-perpetuating cycle of low-grade inflammation. However, specialized pro-resolving mediators (SPMs) – metabolically active lipid byproducts of omega-3 fatty acids – can promote inflammatory deceleration and resolution.,1 Post hoc analysis of the Glue Grant Data developed a mathematical lipidomic expression to better understand genes responsible for production and degradation of resolvins and leukotrienes.,2 Leukotriene Score = (ALOX5 * ALX5AP * LTA4H * LTB4R)/(HPGD + PTGR1 + CYP4F3) Resolvin Score = [(ALOX5 * ALOX15) * (FPR2 + GPR32 + CMKLR1)]/(HPGD + PTGR1) When the targeted genes were scored using a weighted scheme accounting for enzyme and receptor activity, patients with uncomplicated recoveries had higher resolvin scores (P < 0.001) and lower leukotriene scores (P < 0.001). Utilizing our PICS patient data, we recapitulated the aforementioned lipidomic scores above to quantify expression in severe sepsis/septic shock survivors. Results Leukotriene and resolvin scores are depicted in Figure 1 at specific time points 0 (healthy controls), 3 hours, 1 and 14 days. The leukotriene score remains elevated consistent with ongoing inflammatory genotypic expression. Interestingly, the resolvin score also remains elevated in the CCI (Glue Grant complicated cohort) patient population when compared to our Rapid Recovery (RAP or uncomplicated) patients *Accompanied by two graphs depicting correlating numerical values for the aforementioned Leukotriene and Resolvin scores. Conclusions In our patient population of sepsis survivors, the leukotriene score is similarly elevated to the complicated Glue Grant patients of polytrauma. The resolvin score, however, remains elevated in the CCI-PICS population compared to RAP; this is contrary to expected scores if resolution of inflammation is predicted. Funding Sources University of Florida.

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Abstract 21: Endothelial Epsins Promote LPS-Induced Inflammation During Septic Shock

Arteriosclerosis Thrombosis and Vascular Biology ◽

10.1161/atvb.37.suppl_1.21 ◽

2017 ◽

Vol 37 (suppl_1) ◽

Author(s):

Hong Chen

Keyword(s):

Septic Shock ◽

Proinflammatory Cytokine ◽

Cytokine Production ◽

Therapeutic Potential ◽

Lethal Dose ◽

Myeloid Cell ◽

Mutant Mice ◽

Proinflammatory Cytokine Production ◽

Knock Out ◽

Lps Challenge

Introduction: Sepsis is caused by a deleterious host response to infection, which is primarily responsible for further injury of host tissue and cause of organ dysfunction. Despite significant progress, the pathophysiology of sepsis and the underlying regulatory mechanisms are still not fully understood. We have established that endothelial epsins play a pivotal role in mediating internalization and degradation of Thrombomodulin after LPS challenge. Hypothesis: Given LPS triggers “cytokine storm” that causes hyper-permeability in the endothelium of lungs and excessive inflammation, we assessed the hypothesis that epsins play a role in promoting endothelial permeability and augmenting inflammation. Methods and Results: Using innovative tissue-specific inducible epsins double knock out animal models, we investigated the role for epsins during sepsis. We administered lethal dose of LPS into endothelial-specific inducible epsins mutant mice, myeloid cell-specific epsins mutant mice, and platelet-specific epsins mutant mice (n>10). We uncover a potent protective role for endothelial epsins deficiency against the development of LPS-induced sepsis, whereas deletion of epsins in myeloid cells offers 40% ~ 50% of protection, and loss of epsins in platelets exhibits no protection. We further show that endothelial epsin-deficiency upregulates Thrombomodulin surface protein expression by preventing its internalization and subsequent degradation induced by LPS exposure. Sustained surface Thrombomodulin activity subsequently impaired the heightened Tissue Factor expression and activation that usually occurs in response to LPS. Given LPS challenge mimics chronic inflammatory conditions, we show endothelial epsin-deficiency downregulates LPS-induced proinflammatory cytokine production and suppresses endothelial hyper-permeability in lungs assessed by ELSA and Evans Blue perfusion, respectively. Conclusions: Endothelial epsins depletion inhibits septic shock after LPS challenge by protecting Thrombomodulin against internalization and degradation, blocking proinflammatory cytokine production and inhibiting endothelial leakage in the lungs, highlighting the therapeutic potential for targeting epsins during sepsis.

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