A systematic review of experimental treatments for mitochondrial dysfunction in sepsis and multiple organ dysfunction syndrome

Platelet Bioenergetics and Associations With Delirium and Coma in Patients With Sepsis: A Prospective Cohort Study

BACKGROUND

Acute brain dysfunction during sepsis, which manifests as delirium or coma, is common and is associated with multiple adverse outcomes, including longer periods of mechanical ventilation, prolonged hospital stays, and increased mortality. Delirium and coma during sepsis may be manifestations of alteration in systemic metabolism. Because access to brain mitochondria is a limiting factor, measurement of peripheral platelet bioenergetics offers a potential opportunity to understand metabolic changes associated with acute brain dysfunction during sepsis.

RESEARCH QUESTION

Are altered platelet mitochondrial bioenergetics associated with acute brain dysfunction during sepsis?

STUDY DESIGN AND METHODS

We assessed participants with critical illness in the ICU for the presence of delirium or coma via validated assessment measures. Blood samples were collected and processed to isolate and measure platelet mitochondrial oxygen consumption. We used Seahorse extracellular flux to measure directly baseline, proton leak, maximal oxygen consumption rate, and extracellular acidification rate. We calculated adenosine triphosphate-linked, spare respiratory capacity, and nonmitochondrial oxygen consumption rate from the measured values.

RESULTS

Maximum oxygen consumption was highest in patients with coma, as was spare respiratory capacity and extracellular acidification rate in unadjusted analysis. After adjusting for age, sedation, modified Sequential Organ Failure Assessment score without the neurologic component, and preexisting cognitive function, increased spare respiratory capacity remained associated with coma. Delirium was not associated with any platelet mitochondrial bioenergetics.

INTERPRETATION

In this single-center exploratory prospective cohort study, we found that increased platelet mitochondrial spare respiratory capacity was associated with coma in patients with sepsis. Future studies powered to determine any relationship between delirium and mitochondrial respiration bioenergetics are needed.

Impact of Treatment with Antioxidants as an Adjuvant to Standard Therapy in Patients with Septic Shock: Analysis of the Correlation between Cytokine Storm and Oxidative Stress and Therapeutic Effects

Cellular homeostasis is lost or becomes dysfunctional during septic shock due to the activation of the inflammatory response and the deregulation of oxidative stress. Antioxidant therapy administered alongside standard treatment could restore this lost homeostasis. We included 131 patients with septic shock who were treated with standard treatment and vitamin C (Vit C), vitamin E (Vit E), N-acetylcysteine (NAC), or melatonin (MT), in a randomized trial. Organ damage quantified by Sequential Organ Failure Assessment (SOFA) score, and we determined levels of Interleukins (IL) IL1β, Tumor necrosis factor alpha (TNFα), IL-6, monocyte chemoattractant protein-1 (MCP-1), Transforming growth factor B (TGFβ), IL-4, IL-10, IL-12, and Interferon-γ (IFNγ). The SOFA score decreased in patients treated with Vit C, NAC, and MT. Patients treated with MT had statistically significantly reduced of IL-6, IL-8, MCP-1, and IL-10 levels. Lipid peroxidation, Nitrates and nitrites (NO3- and NO2-), glutathione reductase, and superoxide dismutase decreased after treatment with Vit C, Vit E, NAC, and MT. The levels of thiols recovered with the use of Vit E, and all patients treated with antioxidants maintained their selenium levels, in contrast with controls (p = 0.04). The findings regarding oxidative stress markers and cytokines after treatment with antioxidants allow us to consider to future the combined use of antioxidants in a randomized clinical trial with a larger sample to demonstrate the reproducibility of these beneficial effects.

Pretreatment with Kahweol Attenuates Sepsis-Induced Acute Lung Injury via Improving Mitochondrial Homeostasis in a CaMKKII/AMPK-Dependent Pathway

SCOPE

It is well-established that dysregulated mitochondrial homeostasis in macrophages leads to inflammation, oxidative stress, and tissue damage, which are essential in the pathogenesis of sepsis-induced acute lung injury (ALI). Kahweol, a natural diterpene extracted from coffee beans, reportedly possesses anti-inflammatory and mitochondrial protective properties. Herein, the study investigates whether Kahweol can alleviate sepsis-induced ALI and explore the underlying mechanisms.

METHODS AND RESULTS

C57BL/6J mice are intraperitoneally injected with lipopolysaccharide (LPS) for 12 h to induce ALI. Pretreatment with kahweol by gavage for 5 days significantly alleviates lung pathological injury, inflammation, and oxidative stress, accompanied by shifting the dynamic process of mitochondria from fission to fusion, enhancing mitophagy, and activating AMPK. To investigate the underlying molecular mechanisms, differentiated THP-1 cells are cultured in a medium containing Kahweol for 12 h prior to LPS exposure, yielding consistent findings with the in vivo results. Moreover, AMPK inhibitors abrogate the above effects, indicating Kahweol acts in an AMPK-dependent manner. Furthermore, the study explores how Kahweol activates AMPK and finds that this process is mediated by CamKK II.

CONCLUSION

Pretreatment with Kahweol attenuates sepsis-induced acute lung injury via improving mitochondrial homeostasis in a CaMKKII/AMPK-dependent pathway and may be a potential candidate to prevent sepsis-induced ALI.

Optimisation of mitochondrial function as a novel target for resuscitation in haemorrhagic shock: a systematic review

INTRODUCTION

Traumatic injury is one of the leading causes of death worldwide, and despite significant improvements in patient care, survival in the most severely injured patients remains unchanged. There is a crucial need for innovative approaches to improve trauma patient outcomes; this is particularly pertinent in remote or austere environments with prolonged evacuation times to definitive care. Studies suggest that maintenance of cellular homeostasis is a critical component of optimal trauma patient management, and as the cell powerhouse, it is likely that mitochondria play a pivotal role. As a result, therapies that optimise mitochondrial function could be an important future target for the treatment of critically ill trauma patients.

METHODS

A systematic review of the literature was undertaken in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses protocol to determine the potential role of mitochondria in traumatic injury and haemorrhagic shock (HS) and to identify current evidence for mitochondrial optimisation therapies in trauma. Articles were included if they assessed a mitochondrial targeted therapy in comparison to a control group, used a model of traumatic injury and HS and reported a method to assess mitochondrial function.

RESULTS

The search returned 918 articles with 37 relevant studies relating to mitochondrial optimisation identified. Included studies exploring a range of therapies with potential utility in traumatic injury and HS. Therapies were categorised into the key mitochondrial pathways impacted following traumatic injury and HS: ATP levels, cell death, oxidative stress and reactive oxygen species.

CONCLUSION

This systematic review provides an overview of the key cellular functions of the mitochondria following traumatic injury and HS and identifies why mitochondrial optimisation could be a viable and valuable target in optimising outcome in severely injured patients in the future.

Development and Recovery of Liver Injury in Piglets by Incremental Injection of LPS

This study aimed to explore the effects of the incremental injection of lipopolysaccharide (LPS) on liver histopathology, inflammation, oxidative status, and mitochondrial function in piglets. Forty healthy Duroc × Landrace × Yorkshire castrated boars (21 ± 2 days old, weight 6.84 ± 0.11 kg) were randomly assigned to five groups (n = 8) and then slaughtered on days 0 (group 0, without LPS injection), 1 (group 1), 5 (group 5), 9 (group 9), and 15 (group 15) of LPS injection, respectively. The results showed that, compared to the piglets without LPS injection, LPS injection caused liver injury in the early phase, as manifested by the increased activities of serum liver injury-related parameters (aspartate amino transferase, alanine aminotransferase, alkaline phosphatase, cholinesterase, and total bile acid) on day 1, and impaired liver morphology (disordered hepatic cell cord arrangement, dissolved and vacuolized hepatocytes, karyopycnosis, and inflammatory cell infiltration and congestion) on days 1 and 5. Meanwhile, LPS injection caused liver inflammation, oxidative stress, and mitochondrial dysfunction on days 1 and 5, as reflected by the upregulated mRNA expression of TNF-α, IL-6, IL-1β, TLR4, MyD88, and NF-κB; increased MPO and MDA content; and impaired mitochondrial morphology. However, these parameters were ameliorated in the later phase (days 9~15). Taken together, our data indicate that the incremental injection of the LPS-induced liver injury of piglets could be self-repaired.

CoQ10 alleviates hepatic ischemia reperfusion injury via inhibiting NLRP3 activity and promoting Tregs infiltration

Hepatic ischemia-reperfusion injury (IRI) has been concerned as a main complication of liver surgery and transplantation. Previous studies show that reactive oxygen species (ROS) associated inflammation response and contribute to the liver damage during IRI. Coenzyme Q10 (CoQ10) has shown many beneficial effects on abrogating ROS production and ameliorating liver injury. This study found lower CoQ10 level in the process of liver IRI in a mouse model of hepatic IRI. Meanwhile, our results showed that CoQ10 administration significantly attenuate hepatic IRI proved by HE staining, serum ALT/AST. The NOD-like receptor protein 3 (NLRP3) inflammasome is activated by ROS which triggers the activation of inflammatory caspases. In this study, NLRP3 was significantly suppressed by CoQ10 while Foxp3 exhibited increased expression in liver. Furthermore, Kupffer cells (KCs) pretreated with CoQ10 under the condition of hypoxia and reoxygenation contributed to improved CD4⁺CD25⁺Foxp3⁺ regulatory T cells (Tregs) ratio in co-culture system. Furthermore, NLRP3 inflammasome activator treatment in vivo resulted in higher expression of caspase-1 and NLRP3 and reduction of Tregs in liver, which reversed the protection of CoQ10 in the liver injury. Taken together, our study discovered that CoQ10 can suppress NLRP3 activity in KCs and improves Foxp3⁺ Tregs differentiation depending on M2 macrophage polarization of KCs to ameliorate hepatic IRI.

Advances in understanding mechanisms underlying mitochondrial structure and function damage by ozone

Mitochondria are double-membraned organelles found in eukaryotic cells. The integrity of mitochondrial structure and function determines cell destiny. Mitochondria are also the "energy factories of cells." The production of energy is accompanied by reactive oxygen species (ROS) generation. Generally, the production and consumption of ROS maintains a balance in cells. Ozone is a highly oxidizing, harmful substance in ground-level atmosphere. Ozone inhalation causes oxidative injury owing to the generation of ROS, resulting in mitochondrial oxidative stress overload. Oxidative damage to the mitochondria induces a vicious cycle of ROS production which might destroy mitochondrial DNA and mitochondrial structure and function in cells. ROS can alter the phosphorylation of various signaling molecules, triggering a series of downstream signaling pathway reactions. These include inflammatory responses, pyroptosis, autophagy, and apoptosis. Changes involving these molecular mechanisms may be related to the occurrence of disease. According to numerous epidemiological investigations, ozone exposure induces respiratory, cardiovascular, and nervous system diseases in humans. In addition, these systems require large quantities of energy. Hence, the mitochondrial damage caused by ozone may act as a bridge between human diseases. However, the specific molecular mechanisms involved require further investigation. This review discusses our understanding of the structure and function of mitochondria the mechanisms underlying ozone-induced mitochondrial damage.

Biomolecules resveratrol + coenzyme Q10 recover the cell state of human mesenchymal stem cells after 1-methyl-4-phenylpyridinium-induced damage and improve proliferation and neural differentiation

Neurodegenerative disorders are a critical affection with a high incidence around the world. Currently, there are no effective treatments to solve this problem. However, the application of mesenchymal stem cells (MSCs) and antioxidants in neurodegenerative diseases has shown to be a promising tool due to their multiple therapeutic effects. This work aimed to evaluate the effects of a combination of resveratrol (RSV) and coenzyme Q10 (CoQ10) on the proliferation and differentiation of MSC and the protector effects in induced damage. To characterize the MSCs, we performed flow cytometry, protocols of cellular differentiation, and immunocytochemistry analysis. The impact of RSV + CoQ10 in proliferation was evaluated by supplementing 2.5 and 10 μM of RSV + CoQ10 in a cellular kinetic for 14 days. Cell viability and lactate dehydrogenase levels (LDH) were also analyzed. The protective effect of RSV + CoQ10 was assessed by supplementing the treatment to damaged MSCs by 1-methyl-4-phenylpyridinium (MPP+); cellular viability, LDH, and reactive oxygen species (ROS) were evaluated.. MSCs expressed the surface markers CD44, CD73, CD90, and CD105 and showed multipotential ability. The combination of RSV + CoQ10 increased the proliferation potential and cell viability and decreased LDH levels. In addition, it reverted the effect of MPP+-induced damage in MSCs to enhance cell viability and decrease LDH and ROS. Finally, RSV + CoQ10 promoted the differentiation of neural progenitors. The combination of RSV + CoQ10 represents a potential treatment to improve MSCs capacities and protect against neurodegenerative damage.

An Overview on Mitochondrial-Based Therapies in Sepsis-Related Myocardial Dysfunction: Mitochondrial Transplantation as a Promising Approach

Sepsis is defined as a life-threatening organ failure due to dysregulated host response to infection. Despite current advances in our knowledge about sepsis, it is still considered as a major global health challenge. Myocardial dysfunction is a well-defined manifestation of sepsis which is related to worse outcomes in septic patients. Given that the heart is a mitochondria-rich organ and the normal function of mitochondria is essential for successful modulation of septic response, the contribution of mitochondrial damage in sepsis-related myocardial dysfunction has attracted the attention of many scientists. It is widely accepted that mitochondrial damage is involved in sepsis-related myocardial dysfunction; however, effective and potential treatment modalities in clinical setting are still lacking. Mitochondrial-based therapies are potential approaches in sepsis treatment. Although various therapeutic strategies have been used for mitochondrial function improvement, their effects are limited when mitochondria undergo irreversible alterations under septic challenge. Therefore, application of more effective approaches such as mitochondrial transplantation has been suggested. This review highlights the crucial role of mitochondrial damage in sepsis-related myocardial dysfunction, then provides an overview on mitochondrial-based therapies and current approaches to mitochondrial transplantation as a novel strategy, and proposes future directions for more researches in this field.

Antioxidants Attenuate Heat Shock Induced Premature Senescence of Bovine Mesenchymal Stem Cells

Mesenchymal stem cells (MSC) have many roles that are important for the body's proper functioning. When the MSC pool is damaged, it is often correlated with impaired development or health of the organism. MSC are known for their anti-inflammatory, immunomodulatory and trophic characteristics that play an important role in the physiological homeostasis of many tissues. Heat shock impairs MSC capacity by inducing the generation of reactive oxygen species and mitochondrial dysfunction, which, in turn, send the cells into a state of premature senescence. Here, we pre-exposed MSC to melatonin, resveratrol, or curcumin, which are natural antioxidative compounds, and tested the protective effects of these substances from oxidative stress and aging. Our data showed that pre-exposure of MSC to antioxidants decreased reactive oxygen species while mitochondrial damage remained high. Additionally, although the proliferation of the cells was slow, antioxidants protected the cells from premature senescence, and subsequent cytokine release was prevented. We conclude that while elevated temperatures directly cause mitochondrial damage, senescence is induced by elevated ROS levels. We suggest that heat shock alters cell and tissue homeostasis by several independent mechanisms; however, reducing tissue senescence will reduce damage and provide a pathway to overcome physiological challenges in animals.

Regulation of Oxidative Phosphorylation of Liver Mitochondria in Sepsis

The link between liver dysfunction and decreased mitochondrial oxidative phosphorylation in sepsis has been clearly established in experimental models. Energy transduction is plastic: the efficiency of mitochondrial coupling collapses in the early stage of sepsis but is expected to increase during the recovery phases of sepsis. Among the mechanisms regulating the coupling efficiency of hepatic mitochondria, the slipping reactions at the cytochrome oxidase and ATP synthase seem to be a determining element, whereas other regulatory mechanisms such as those involving proton leakage across the mitochondrial membrane have not yet been formally proven in the context of sepsis. If the dysfunction of hepatic mitochondria is related to impaired cytochrome c oxidase and ATP synthase functions, we need to consider therapeutic avenues to restore their activities for recovery from sepsis. In this review, we discussed previous findings regarding the regulatory mechanism involved in changes in the oxidative phosphorylation of liver mitochondria in sepsis, and propose therapeutic avenues to improve the functions of cytochrome c oxidase and ATP synthase in sepsis.

Altered Serum Acylcarnitines Profile after a Prolonged Stay in Intensive Care

A stay in intensive care unit (ICU) exposes patients to a risk of carnitine deficiency. Moreover, acylated derivates of carnitine (acylcarnitines, AC) are biomarkers for metabolic mitochondrial dysfunction that have been linked to post-ICU disorders. This study aimed to describe the AC profile of survivors of a prolonged ICU stay (≥7 days). Survivors enrolled in our post-ICU clinic between September 2020 and July 2021 were included. Blood analysis was routinely performed during the days after ICU discharge, focusing on metabolic markers and including AC profile. Serum AC concentrations were determined by LC-MS/MS and were compared to the reference ranges (RR) established from serum samples of 50 non-hospitalized Belgian adults aged from 18 to 81 years. A total 162 patients (65.4% males, age 67 (58.7−73) years) survived an ICU stay of 9.7 (7.1−19.3) days and were evaluated 5 (3−8) days after discharge. Their AC profile was significantly different compared to RR, mostly in terms of short chain AC: the sum of C3, C4 and C5 derivates reached 1.36 (0.98−1.99) and 0.86 (0.66−0.99) µmol/L respectively (p < 0.001). Free carnitine (C0) concentration of survivors (46.06 (35.04−56.35) µmol/L) was similar to RR (43.64 (36.43−52.96) µmol/L) (p = 0.55). C0 below percentile 2.5 of RR was observed in 6/162 (3.7%) survivors. Their total AC/C0 ratio was 0.33 (0.22−0.42). A ratio above 0.4 was observed in 45/162 (27.8%) patients. In ICU survivors, carnitine deficiency was rare, but AC profile was altered and AC/C0 ratio was abnormal in more than 25%. The value of AC profile as a marker of post-ICU dysmetabolism needs further investigations.

Agomelatine protects heart and aorta against lipopolysaccharide-induced cardiovascular toxicity via inhibition of NF-kβ phosphorylation

The aim of this study was to investigate the possible ameliorating effects of agomelatine (AGO) on lipopolysaccharide (LPS)-induced endothelial and cardiac damage. Twenty-four female Wistar Albino rats divided into 3 groups as follows: Control, LPS and LPS + AGO. Total oxidant status (TOS), total antioxidant status (TAS), nuclear factor kappa beta (NF-kβ)/p65, p-NF-kβ, full caspase-8 (Cas-8) and cleaved cas-8 levels were measured in cardiac tissues and creatine kinase MB (CKMB), aspartate aminotransferase (AST), lactate dehydrogenase (LDH) levels in blood biochemically. In addition; cas-8, sirtuin-1 (SIRT-1), interleukin-4 (IL-4), interleukin-10 (IL-10), haptoglobin measured histopathologically in cardiac and aortic tissues. The levels of CKMB, AST, LDH and TOS were increased and TAS were decreased in the LPS group. In Western blot analyses NF-kβ/p65, p-NF-kβ/p65, full and cleaved cas-8 protein levels increased in cardiac tissues of LPS group. In histopathological and immunohistochemical evaluation of the heart sections; hyperemia, micro-hemorrhages and inflammatory cell infiltrations, increase of cas-8, haptoglobin, IL-4 and IL-10 and decrease of SIRT-1 levels were observed in cardiac and endothelial tissues of LPS groups. AGO treatment reversed all these parameters. It was shown that LPS-induced inflammation, oxidative stress and apoptosis via increasing of NF-kβ/p65 signaling, decreasing of SIRT-1 levels and increase of cas-8 levels in heart and endothelial tissues respectively. AGO corrected all these parameters by its antioxidant, antiinflammatory and antiapoptotic activities.

DNA-PKcs promotes sepsis-induced multiple organ failure by triggering mitochondrial dysfunction

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DNA-PKcs inhibition attenuates sepsis-related MODS by preserving mitochondrial function and homeostasis.

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Organ-specific deletion of DNA-PKcs sustained myocardial contraction, liver function, and kidney performance in LPS-challenged mice.

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DNA-PKcs deficiency supported cardiomyocyte function through improving mitochondrial respiration.

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DNA-PKcs deficiency alleviated liver dysfunction by inhibiting LPS-induced mitochondrial oxidative stress and apoptosis.

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DNA-PKcs deficiency attenuated kidney dysfunction by normalizing mitochondrial dynamics and biogenesis, as well as mitophagy.

Introduction

Multiple organ failure is the commonest cause of death in septic patients.

Objectives

This study was undertaken in an attempt to elucidate the functional importance of DNA-dependent protein kinase catalytic subunit (DNA-PKcs) on mitochondrial dysfunction associated with the development and progression of sepsis-related multiple organ dysfunction syndrome (MODS).

Methods

Cardiomyocyte-specific DNA-PKcs knockout (DNA-PKcs^CKO) mice, liver-specific DNA-PKcs knockout (DNA-PKcs^LKO) mice, and kidney tubular cell-specific DNA-PKcs knockout (DNA-PKcs^TKO) mice were used to generate an LPS-induced sepsis model. Echocardiography, serum biochemistry, and tissue microscopy were used to analyze organ damage and morphological changes induced by sepsis. Mitochondrial function and dynamics were determined by qPCR, western blotting, ELISA, and mt-Keima and immunofluorescence assays following siRNA-mediated DNA-PKCs knockdown in cardiomyocytes, hepatocytes, and kidney tubular cells.

Results

DNA-PKcs deletion attenuated sepsis-mediated myocardial damage through improving mitochondrial metabolism. Loss of DNA-PKcs protected the liver against sepsis through inhibition of mitochondrial oxidative damage and apoptosis. DNA-PKcs deficiency sustained kidney function upon LPS stress through normalization of mitochondrial fission/fusion events, mitophagy, and biogenesis.

Conclusion

We conclude that strategies targeting DNA-PKcs expression or activity may be valuable therapeutic options to prevent or reduce mitochondrial dysfunction and organ damage associated with sepsis-induced MODS.

Sirtuins and Sepsis: Cross Talk between Redox and Epigenetic Pathways

Sepsis and septic shock are the leading causes of death among hospitalized patients in the US. The immune response in sepsis transitions from a pro-inflammatory and pro-oxidant hyper-inflammation to an anti-inflammatory and cytoprotective hypo-inflammatory phase. While 1/3rd sepsis-related deaths occur during hyper-, a vast majority of sepsis-mortality occurs during the hypo-inflammation. Hyper-inflammation is cytotoxic for the immune cells and cannot be sustained. As a compensatory mechanism, the immune cells transition from cytotoxic hyper-inflammation to a cytoprotective hypo-inflammation with anti-inflammatory/immunosuppressive phase. However, the hypo-inflammation is associated with an inability to clear invading pathogens, leaving the host susceptible to secondary infections. Thus, the maladaptive immune response leads to a marked departure from homeostasis during sepsis-phases. The transition from hyper- to hypo-inflammation occurs via epigenetic programming. Sirtuins, a highly conserved family of histone deacetylators and guardians of homeostasis, are integral to the epigenetic programming in sepsis. Through their anti-inflammatory and anti-oxidant properties, the sirtuins modulate the immune response in sepsis. We review the role of sirtuins in orchestrating the interplay between the oxidative stress and epigenetic programming during sepsis.

A metabolomic endotype of bioenergetic dysfunction predicts mortality in critically ill patients with acute respiratory failure

Acute respiratory failure (ARF) requiring mechanical ventilation, a complicating factor in sepsis and other disorders, is associated with high morbidity and mortality. Despite its severity and prevalence, treatment options are limited. In light of accumulating evidence that mitochondrial abnormalities are common in ARF, here we applied broad spectrum quantitative and semiquantitative metabolomic analyses of serum from ARF patients to detect bioenergetic dysfunction and determine its association with survival. Plasma samples from surviving and non-surviving patients (N = 15/group) were taken at day 1 and day 3 after admission to the medical intensive care unit and, in survivors, at hospital discharge. Significant differences between survivors and non-survivors (ANOVA, 5% FDR) include bioenergetically relevant intermediates of redox cofactors nicotinamide adenine dinucleotide (NAD) and NAD phosphate (NADP), increased acyl-carnitines, bile acids, and decreased acyl-glycerophosphocholines. Many metabolites associated with poor outcomes are substrates of NAD(P)-dependent enzymatic processes, while alterations in NAD cofactors rely on bioavailability of dietary B-vitamins thiamine, riboflavin and pyridoxine. Changes in the efficiency of the nicotinamide-derived cofactors' biosynthetic pathways also associate with alterations in glutathione-dependent drug metabolism characterized by substantial differences observed in the acetaminophen metabolome. Based on these findings, a four-feature model developed with semi-quantitative and quantitative metabolomic results predicted patient outcomes with high accuracy (AUROC = 0.91). Collectively, this metabolomic endotype points to a close association between mitochondrial and bioenergetic dysfunction and mortality in human ARF, thus pointing to new pharmacologic targets to reduce mortality in this condition.

Analysis of the Plasma Metabolome after Trauma, Novel Circulating Sphingolipid Signatures, and In-Hospital Outcomes

BACKGROUND

Trauma is the leading cause of death and disability for individuals under age 55. Many severely injured trauma patients experience complicated clinical courses despite appropriate initial therapy. We sought to identify novel circulating metabolomic signatures associated with clinical outcomes following trauma.

STUDY DESIGN

Untargeted metabolomics and circulating plasma immune mediator analysis was performed on plasma collected during 3 post-injury time periods (<6 hours [h], 6 h-24h, day 2-day 5) in critically ill trauma patients enrolled between April 2004 and May 2013 at UPMC Presbyterian Hospital in Pittsburgh, PA. Inclusion criteria were age ≥ 18 years, blunt mechanism, ICU admission, and expected survival ≥ 24 h. Exclusion criteria were isolated head injury, spinal cord injury, and pregnancy. Exploratory endpoints included length of stay (overall and ICU), ventilator requirements, nosocomial infection, and Marshall organ dysfunction (MOD) score. The top 50 metabolites were isolated using repeated measures ANOVA and multivariate empirical Bayesian analysis for further study.

RESULTS

Eighty-six patients were included for analysis. Sphingolipids were enriched significantly (chi-square, p < 10^-6) among the top 50 metabolites. Clustering of sphingolipid patterns identified 3 patient subclasses: nonresponders (no time-dependent change in sphingolipids, n = 41), sphingosine/sphinganine-enhanced (n = 24), and glycosphingolipid-enhanced (n = 21). Compared with the sphingolipid-enhanced subclasses, nonresponders had longer mean length of stay, more ventilator days, higher MOD scores, and higher circulating levels of proinflammatory immune mediators IL-6, IL-8, IL-10, MCP1/CCL2, IP10/CXCL10, and MIG/CXCL9 (all p < 0.05), despite similar Injury Severity Scores (p = 0.12).

CONCLUSIONS

Metabolomic analysis identified broad alterations in circulating plasma sphingolipids after blunt trauma. Circulating sphingolipid signatures and their association with both clinical outcomes and circulating inflammatory mediators suggest a possible link between sphingolipid metabolism and the immune response to trauma.

Impairment of PGC-1 Alpha Up-Regulation Enhances Nitrosative Stress in the Liver during Acute Pancreatitis in Obese Mice

Acute pancreatitis is an inflammatory process of the pancreatic tissue that often leads to distant organ dysfunction. Although liver injury is uncommon in acute pancreatitis, obesity is a risk factor for the development of hepatic complications. The aim of this work was to evaluate the role of PGC-1α in inflammatory response regulation in the liver and its contribution to the detrimental effect of obesity on the liver during acute pancreatitis. For this purpose, we induced acute pancreatitis by cerulein in not only wild-type (WT) and PGC-1α knockout (KO) mice, but also in lean and obese mice. PGC-1α levels were up-regulated in the mice livers with pancreatitis. The increased PGC-1α levels were bound to p65 to restrain its transcriptional activity toward Nos2. Lack of PGC-1α favored the assembly of the p65/phospho-STAT3 complex, which promoted Nos2 expression during acute pancreatitis. The increased transcript Nos2 levels and the pro-oxidant liver status caused by the down-regulated expression of the PGC-1α-dependent antioxidant genes enhanced nitrosative stress and decreased energy charge in the livers of the PGC-1α KO mice with pancreatitis. It is noteworthy that the PGC-1α levels lowered in the obese mice livers, which increased the Nos2 mRNA expression and protein nitration levels and decreased energy charge during pancreatitis. In conclusion, obesity impairs PGC-1α up-regulation in the liver to cause nitrosative stress during acute pancreatitis.

Ultrastructural changes in endothelial cells of buffaloes following in-vitro exposure to Pasteurella multocida B:2

BACKGROUND

Pasteurella multocida B:2 causes haemorrhagic septicaemia in cattle and buffaloes. However, buffaloes are found to be more susceptible to the infection than cattle. Upon infection, the pathogen rapidly spread from the respiratory tract to the blood circulation within 16-72 h, causing septicaemia. So far, limited study has been conducted to evaluate the response of endothelial cells of buffalo towards P. multocida B:2 and its lipopolysaccharide (LPS). This study aimed to evaluate the ultrastructural changes in the aortic endothelium of buffaloes (BAEC) following exposure to P. multocida B:2 and its endotoxin. The endothelial cells were harvested from the aorta of healthy buffaloes and were prepared as monolayer cell cultures. The cultures were divided into 3 groups before Group 1 was inoculated with 10⁷ cfu/ml of whole cell P. multocida B:2, Group 2 with LPS, which was extracted earlier from 10⁷ cfu/ml of P. multocida B:2 and Group 3 with sterile cell culture medium. The cells were harvested at 0, 6, 12, 18, 24, 36, and 48 h post-inoculation for assessment of cellular changes using transmission electron microscopy.

RESULTS

The BAEC of Groups 1 and 2 demonstrated moderate to severe endothelial lysis, suggestive of acute cellular injury. In general, severity of the ultrastructural changes increased with the time of incubation but no significant difference (p > 0.05) in the severity of the cellular changes between Groups 1 and 2 was observed in the first 18 h. The severity of lesions became significant (p < 0.05) thereafter. Both treated Groups 1 and 2 showed significantly (p < 0.05) more severe cellular changes compared to the control Group 3 from 6 h post-inoculation. The severity reached peak at the end of the study period with score 3 for Group 1 and score 2.8 for Group 2.

CONCLUSIONS

This study revealed that both whole cells P. multocida B:2 and LPS endotoxin showed similar moderate to severe cellular damage, but whole-cell P. multocida B:2 appeared to be more potent in causing much severe damage than LPS alone.

Qingyi decoction protects against myocardial injuries induced by severe acute pancreatitis

BACKGROUND

We studied the protective effects of Qingyi decoction (QYD) (a Traditional Chinese Medicine) against severe acute pancreatitis (SAP)-induced myocardial infarction (MI).

AIM

To study the function and mechanism of QYD in the treatment of myocardial injuries induced by SAP.

METHODS

Ultrasonic cardiography, hematoxylin and eosin staining, immunohistochemistry, qRT-PCR, western blot, enzyme-linked immunosorbent assays, and apoptosis staining techniques were used to determine the effects of QYD following SAP-induced MI in Sprague-Dawley rats.

RESULTS

Our SAP model showed severe myocardial histological abnormalities and marked differences in the symptoms, mortality rate, and ultrasonic cardiography outputs among the different groups compared to the control. The expression of serum cytokines [interleukin (IL)-1ß, IL-6, IL-8, IL-12, amyloid β, and tumor necrosis factor-α] were significantly higher in the SAP versus QYD treated group (P < 0.05 for all). STIM1 and Orai1 expression in myocardial tissue extracts were significantly decreased post QYD gavage (P < 0.001). There was no significant histological difference between the 2-aminoethyl diphenylborinate inhibitor and QYD groups. The SAP group had a significantly higher apoptosis index score compared to the QYD group (P < 0.001).

CONCLUSION

QYD conferred cardio-protection against SAP-induced MI by regulating myocardial-associated protein expression (STIM1 and Orai1).

Hypothermia Effects on Liver and Kidney Oxidative Stress Parameters in an Experimental Model of Sepsis in Rats

INTRODUCTION

Oxidative stress (OS) seems to be an important mediator of cellular injury, from which sepsis can proceed. Studies have demonstrated the protective effect of controlled hypothermia in sepsis. This study aimed to evaluate its effects on OS parameters in rat hepatic and renal tissue septic after caecal ligation and puncture (CLP).

MATERIAL AND METHODS

Three groups were appointed (10 rats/group): C (control), SN (sepsis normothermic), and SH (sepsis hypothermic). Ten hours from CLP, the liver and kidneys were harvested and total protein concentration, superoxide dismutase (SOD), glutathione peroxidase (GPx) activities, lipid peroxidation level (malondialdehyde (MDA), carbonylated proteins (2,4-dinitrophenylhydrazine (DNPH), and fatty acid profile were analysed.

RESULTS

Sepsis significantly increased SOD and GPx activities in the liver, regardless of the temperature. In renal tissue, GPx activity increased significantly in normothermic conditions and SOD tended to decrease in hypothermic conditions. MDA and DNPH concentrations increase in both tissues after CLP. Hypothermia significantly lowered MDA in the liver but only changed it insignificantly in the kidneys. The DNPH in the liver and kidneys was significantly lower in hypothermic conditions. The unsaturated-to-saturated fatty acids ratio was significantly lower in sepsis, and the fall in temperature raised this ratio.

CONCLUSION

Experimentally induced sepsis in rats enhances OS in the liver and kidneys. The effect of hypothermia on OS indices is dependent on the type of tissue.

Cerebral edema and liver disease: Classic perspectives and contemporary hypotheses on mechanism

Liver disease is a growing public health concern. Hepatic encephalopathy, the syndrome of brain dysfunction secondary to liver disease, is a frequent complication of both acute and chronic liver disease and cerebral edema (CE) is a key feature. While altered ammonia metabolism is a key contributor to hepatic encephalopathy and CE in liver disease, there is a growing appreciation that additional mechanisms contribute to CE. In this review we will begin by presenting three classic perspectives that form a foundation for a discussion of CE in liver disease: 1) CE is unique to acute liver failure, 2) CE in liver disease is only cytotoxic, and 3) CE in liver disease is primarily an osmotically mediated consequence of ammonia and glutamine metabolism. We will present each classic perspective along with more recent observations that call in to question that classic perspective. After highlighting these areas of debate, we will explore the leading contemporary mechanisms hypothesized to contribute to CE during liver disease.

Multiple Organ Dysfunction Syndrome

Multiple organ dysfunction syndrome (MODS) is one of the most common syndromes of critical illness and the leading cause of mortality among critically ill patients. Multiple organ dysfunction syndrome is the clinical consequence of a dysregulated inflammatory response, triggered by clinically diverse factors with the main pillar of management being invasive organ support. During the last years, the advances in the clarification of the molecular pathways that trigger, mitigate, and determine the outcome of MODS have led to the increasing recognition of MODS as a distinct disease entity with distinct etiology, pathophysiology, and potential future therapeutic interventions. Given the lack of effective treatment for MODS, its early recognition, the early intensive care unit admission, and the initiation of invasive organ support remain the most effective strategies of preventing its progression and improving outcomes.

Comparison of olive leaf, olive oil, palm oil, and omega-3 oil in acute kidney injury induced by sepsis in rats

Background

Hypotension, increased production of reactive oxygen species, and inflammation are all observed in experimental models of sepsis induced by lipopolysaccharide (LPS).

Purpose

The aim of this study was to evaluate the effects of an ethanolic extract of Brazilian olive leaf (Ex), Brazilian olive oil (Olv), Ex + Olv (ExOlv), and palm oil (Pal) in comparison to the effects of omega-3 fish oil (Omg) in a rat model of sepsis-induced acute kidney injury.

Materials

Wistar rats were divided into seven groups (seven per group), which were either untreated (control) or treated with LPS, LPS + Ex, LPS + ExOlv, LPS + Olv, LPS + Omg, or LPS + Pal.

Results

Lower values of creatinine clearance and blood pressure were observed in the LPS-treated group, and these values were not affected by Ex, Olv, ExOlv, Pal, or Omg treatment. Mortality rates were significantly lower in rats exposed to LPS when they were also treated with Ex, ExOlv, Olv, Pal, or Omg. These treatments also decreased oxidative stress and inflammation (Tumor necrosis factor alpha, interleukin-1 beta) and increased interleukin-10 levels and cell proliferation, which were associated with decreased apoptosis in kidney tissue.

Conclusion

Ex and Pal treatments were beneficial in septic rats, since they increased survival rate and did not aggravate inflammation. However, the most effective treatments for septic rats were Olv in comparison to Omg. These natural food substances could enable the development of effective therapeutic interventions to sepsis.

Mitochondrial quality control mechanisms as potential therapeutic targets in sepsis-induced multiple organ failure

Sepsis is a dysregulated response to severe infection characterized by life-threatening organ failure and is the leading cause of mortality worldwide. Multiple organ failure is the central characteristic of sepsis and is associated with poor outcome of septic patients. Ultrastructural damage to the mitochondria and mitochondrial dysfunction are reported in sepsis. Mitochondrial dysfunction with subsequent ATP deficiency, excessive reactive oxygen species (ROS) release, and cytochrome c release are all considered to contribute to organ failure. Consistent mitochondrial dysfunction leads to reduced mitochondrial quality control capacity, which eliminates dysfunctional and superfluous mitochondria to maintain mitochondrial homeostasis. Mitochondrial quality is controlled through a series of processes including mitochondrial biogenesis, mitochondrial dynamics, mitophagy, and transport processes. Several studies have indicated that multiple organ failure is ameliorated by restoring mitochondrial quality control mechanisms and is further amplified by defective quality control mechanisms. This review will focus on advances concerning potential mechanisms in regulating mitochondrial quality control and impacts of mitochondrial quality control on the progression of sepsis.

Whole Blood Redox Potential Correlates With Progressive Accumulation of Oxygen Debt and Acts as A Marker of Resuscitation in A Swine Hemorrhagic Shock Model

INTRODUCTION

Oxidation-reduction reactions involve electron exchanges that require optimal balance for proper cell function. This balance is measured via redox potential and reflects oxidative stress. Despite the critical role of oxidative stress in critical illness and injury, little is known regarding redox potential. We hypothesize redox potential measurements will correlate with accumulation of O2 debt produced by hemorrhage over time.

METHODS

Ten swine were studied using a polytrauma hemorrhagic shock model. Whole blood and plasma redox potential measures were obtained at defined stages of O2 debt (20 mL/kg, 40 mL/kg, 60 mL/kg, 80 mL/kg), and through resuscitation. Redox potential was determined by measuring open circuit potential using novel gold nanoporous electrodes with Ag/AgCl reference.

RESULTS

Whole blood redox potential showed negative change as O2 debt accumulated, exhibiting positive response during resuscitation, and correlated with O2 debt across all animals (P < 0.001). Redox potential changes throughout O2 debt accrual were significant compared with baseline (P≤0.05), and at end resuscitation compared with O2 debt 60 mL/kg (P = 0.05) and 80 mL/kg (P = 0.02). Whole blood redox potential measures also correlated with oxygen extraction ratio, ScvO2, and lactic acid, appearing very sensitive to acute changes. Plasma redox potential showed no correlation with O2 debt.

CONCLUSIONS

Whole blood redox potential demonstrates significant correlation to O2 debt at all stages in this model. These results set the stage for further study of redox potential as a direct measure of oxidative stress and potential clinical tool. Given redox potential plasma performance, these measures should be made in whole blood versus plasma.

Approach of minimal invasive monitoring and initial treatment of the septic patient in emergency medicine

Sepsis and septic shock constitute a complex disease condition that requires the engagement of several medical specialties. A great number of patients with this disease are constantly admitted to the emergency department, which warrants the need for emergency physicians to lead in the recognition and early management of septic patients. Timely and appropriate interventions may help reduce mortality in a disease with an unacceptably high mortality rate. Poor control of cellular hypoperfusion is one of the most influential mechanisms contributing to the high mortality rate in these patients. This article aims to make an evidence-based approach and an algorithm for the active identification of hypoperfusion in patients with suspicion of severe infection, based on both clinical variables (capillary refill, mottling index, left ventricular function by ultrasound, temperature gradient, etc.) and laboratory-measured variables (lactate, central venous oxygen saturation [ScvO₂], and venous-to-arterial carbon dioxide tension difference [P (v-a) CO₂]). Such variables are feasible to use in the emergency department and would help to explain the cause behind the inadequate oxygen use by cells, thereby guiding treatment at the macrovascular, microvascular, or cellular level.

Clinical use of plasma lactate concentration. Part 2: Prognostic and diagnostic utility and the clinical management of hyperlactatemia

OBJECTIVE

To review the current literature pertaining to the use of lactate as a prognostic indicator and therapeutic guide, the utility of measuring lactate concentrations in body fluids other than blood or plasma, and the clinical management of hyperlactatemia in dogs, cats, and horses.

DATA SOURCES

Articles were retrieved without date restrictions primarily via PubMed, Scopus, and CAB Abstracts as well as by manual selection.

HUMAN AND VETERINARY DATA SYNTHESIS

Increased plasma lactate concentrations are associated with increased morbidity and mortality. In populations with high mortality, hyperlactatemia is moderately predictive in identifying nonsurvivors. Importantly, eulactatemia predicts survival better than hyperlactatemia predicts death. Consecutive lactate measurements and calculated relative measures appear to outperform single measurements. The use of lactate as a therapeutic guide has shown promising results in people but is relatively uninvestigated in veterinary species. Increased lactate concentrations in body fluids other than blood should raise the index of suspicion for septic or malignant processes. Management of hyperlactatemia should target the underlying cause.

CONCLUSION

Lactate is a valuable triage and risk stratification tool that can be used to separate patients into higher and lower risk categories. The utility of lactate concentration as a therapeutic target and the measurement of lactate in body fluids shows promise but requires further research.

Continuous blood purification ameliorates clinical signs and corrects the plasma phospholipid levels of patients with multiple organ dysfunction syndromes

BACKGROUND

Multiple organ dysfunction syndromes (MODS) is reported as a leading cause of mortality in intensive care units. Recently, continuous blood purification (CBP) has been mostly applied for MODS treatment. Thus, the purpose of this study was to investigate the effects of CBP on plasma phospholipid level in patients with MODS.

METHODS

A total of 126 patients with MODS and 120 healthy people were collected. The serum cytokine levels, blood biochemical parameters, and blood gas indexes were detected, and the correlation among phospholipid compounds with serum cytokine levels, blood biochemical parameters, and blood gas indexes was analyzed.

RESULTS

Before CBP, levels of body temperature, RR, HR, CVP, IL-6, IL-10, TNF-α, BUN, SCr, PaCO₂ , SM747, and LPC540 were obviously higher, and pH, HCO_3- , PaO₂ , SaO₂ , PE750, PI885, PC792, PC826, PC830, PC854, PC802, and PG747 were lower in the MODS group than those in the control group. During CBP, the MODS group had gradually declined RR, CVP, levels of IL-6, IL-10 and TNF-α, BUN, SCr, PaCO₂ , SM747, and LPC540 and increased HCO_3- , PaO₂ and SaO₂ , PE750, PI885, PC792, PC826, PC830, PC854, PC802, and PG747. Besides, levels of PE750, PI885, PC792, PC826, PC830, PC854, PC802, and PG747 had an obvious negative correlation with levels of TNF-α, IL-10, IL-6, BUN, SCr, and PaCO₂ , and a significant positive correlation with levels of HCO_3- , PaO₂ , and SaO₂ .

CONCLUSION

CBP could effectively ameliorate clinical signs of patients with MODS and correct the plasma phospholipid levels.

Effects of Erdosteine in Experimental Sepsis Model in Rats

Objective

Erdosteine is a mucolytic agent that is known to possess antioxidant effects. This study investigated the effects of erdosteine on endothelin-1 (ET-1) levels and oxidative stress parameters superoxide dismutase (SOD) and malondialdehyde (MDA) in a rat sepsis model.

Methods

Four groups of Wistar albino rats (n=8 per group) were randomly allocated to the following groups: sham (group 1), sepsis (group 2), erdosteine control (group 3) and a sepsis group pretreated with erdosteine (group 4). Sepsis was induced using E. Coli ATCC 25922 inoculation. Serum ET-1, liver tissue SOD and MDA levels were determined in all groups.

Results

ET-1 levels were significantly higher in group 2 compared to groups 1, 3 and 4 (p<0.001, p=0.002 and p<0.001, respectively). Similarly, MDA levels in groups 1, 3 and 4 were significantly lower relative to group 2 (p<0.001, p=0.022 and p=0.010, respectively). Additionally, SOD activities in these same three groups were found to be significantly higher than those in group 2 (p<0.001, p=0.004 and p=0.028, respectively).

Conclusion

In conclusion, erdosteine decreases ET-1 levels and ameliorates oxidative stress parameters induced by sepsis in an experimental rat model of sepsis.

Nitrite administration improves sepsis-induced myocardial and mitochondrial dysfunction by modulating stress signal responses

PURPOSE

A specific therapeutic strategy in sepsis-induced myocardial dysfunction remains to be determined. Nitrite may have cardioprotective effects against sepsis-induced myocardial dysfunction. This study investigated the cardioprotective effects of nitrite on myocardial function, mitochondrial bioenergetics, and its underlying molecular mechanisms in severe septic rats.

METHODS

Sepsis was induced in male Wistar rats by cecal ligation and puncture (CLP). After CLP, we administered normal saline (NS group) or nitrite (nitrite group) subcutaneously. We administered nitrite at different doses (0.1-10 mg/kg) to ascertain the most effective dose and examined cardiac function in an isolated heart experiment 8 h after CLP. We investigated mitochondrial bioenergetics and molecular mechanisms underlying the administration of nitrite in vitro.

RESULTS

In isolated heart experiments, the left ventricular developed pressure (96 ± 5 mmHg) at a moderate nitrite dose (1.0 mg/kg) was significantly higher than that in the NS group (75 ± 4 mmHg, P < 0.05). Mitochondrial oxidative phosphorylation in the nitrite group was significantly higher than that in the NS group (P < 0.01). Immunoblotting revealed that nitrite significantly increased the phosphorylation of Akt (P < 0.05) and reduced the nuclear translocation of NF-κB (P < 0.05) compared with the NS group. Nitrite was also shown to improve the rate of survival in severe septic rats (P < 0.001).

CONCLUSIONS

Our results showed that a moderate nitrite dose improved septic myocardial dysfunction at organ, cellular, and molecular levels via modulation of stress signal responses, which resulted in an improvement in survival.

Integrative model of leukocyte genomics and organ dysfunction in heart failure patients requiring mechanical circulatory support: a prospective observational study

BACKGROUND

The implantation of mechanical circulatory support devices in heart failure patients is associated with a systemic inflammatory response, potentially leading to death from multiple organ dysfunction syndrome. Previous studies point to the involvement of many mechanisms, but an integrative hypothesis does not yet exist. Using time-dependent whole-genome mRNA expression in circulating leukocytes, we constructed a systems-model to improve mechanistic understanding and prediction of adverse outcomes.

METHODS

We sampled peripheral blood mononuclear cells from 22 consecutive patients undergoing mechanical circulatory support device (MCS) surgery, at 5 timepoints: day -1 preoperative, and postoperative days 1, 3, 5, and 8. Clinical phenotyping was performed using 12 clinical parameters, 2 organ dysfunction scoring systems, and survival outcomes. We constructed a strictly phenotype-driven time-dependent non-supervised systems-representation using weighted gene co-expression network analysis, and annotated eigengenes using gene ontology, pathway, and transcription factor binding site enrichment analyses. Genes and eigengenes were mapped to the clinical phenotype using a linear mixed-effect model, with Cox models also fit at each timepoint to survival outcomes.

RESULTS

We inferred a 19-module network, in which most module eigengenes correlated with at least one aspect of the clinical phenotype. We observed a response of advanced heart failure patients to surgery orchestrated into stages: first, activation of the innate immune response, followed by anti-inflammation, and finally reparative processes such as mitosis, coagulation, and apoptosis. Eigengenes related to red blood cell production and extracellular matrix degradation became predictors of survival late in the timecourse corresponding to multiorgan dysfunction and disseminated intravascular coagulation.

CONCLUSIONS

Our model provides an integrative representation of leukocyte biology during the systemic inflammatory response following MCS device implantation. It demonstrates consistency with previous hypotheses, identifying a number of known mechanisms. At the same time, it suggests novel hypotheses about time-specific targets.

The immune system's role in sepsis progression, resolution, and long-term outcome

Sepsis occurs when an infection exceeds local tissue containment and induces a series of dysregulated physiologic responses that result in organ dysfunction. A subset of patients with sepsis progress to septic shock, defined by profound circulatory, cellular, and metabolic abnormalities, and associated with a greater mortality. Historically, sepsis-induced organ dysfunction and lethality were attributed to the complex interplay between the initial inflammatory and later anti-inflammatory responses. With advances in intensive care medicine and goal-directed interventions, early 30-day sepsis mortality has diminished, only to steadily escalate long after "recovery" from acute events. As so many sepsis survivors succumb later to persistent, recurrent, nosocomial, and secondary infections, many investigators have turned their attention to the long-term sepsis-induced alterations in cellular immune function. Sepsis clearly alters the innate and adaptive immune responses for sustained periods of time after clinical recovery, with immune suppression, chronic inflammation, and persistence of bacterial representing such alterations. Understanding that sepsis-associated immune cell defects correlate with long-term mortality, more investigations have centered on the potential for immune modulatory therapy to improve long-term patient outcomes. These efforts are focused on more clearly defining and effectively reversing the persistent immune cell dysfunction associated with long-term sepsis mortality.

Skeletal Muscle and Lymphocyte Mitochondrial Dysfunctions in Septic Shock Trigger ICU-Acquired Weakness and Sepsis-Induced Immunoparalysis

Fundamental events driving the pathological processes of septic shock-induced multiorgan failure (MOF) at the cellular and subcellular levels remain debated. Emerging data implicate mitochondrial dysfunction as a critical factor in the pathogenesis of sepsis-associated MOF. If macrocirculatory and microcirculatory dysfunctions undoubtedly participate in organ dysfunction at the early stage of septic shock, an intrinsic bioenergetic failure, sometimes called "cytopathic hypoxia," perpetuates cellular dysfunction. Short-term failure of vital organs immediately threatens patient survival but long-term recovery is also severely hindered by persistent dysfunction of organs traditionally described as nonvital, such as skeletal muscle and peripheral blood mononuclear cells (PBMCs). In this review, we will stress how and why a persistent mitochondrial dysfunction in skeletal muscles and PBMC could impair survival in patients who overcome the first acute phase of their septic episode. First, muscle wasting protracts weaning from mechanical ventilation, increases the risk of mechanical ventilator-associated pneumonia, and creates a state of ICU-acquired muscle weakness, compelling the patient to bed. Second, failure of the immune system ("immunoparalysis") translates into its inability to clear infectious foci and predisposes the patient to recurrent nosocomial infections. We will finally emphasize how mitochondrial-targeted therapies could represent a realistic strategy to promote long-term recovery after sepsis.

Saturated hydrogen saline ameliorates lipopolysaccharide-induced acute lung injury by reducing excessive autophagy

The pathogenesis of acute lung injury (ALI) induced by lipopolysaccharide (LPS) involves excessive pulmonary inflammation and oxidative stress. In turn, autophagy is associated with inflammatory diseases and organ dysfunction, and studies have demonstrated that LPS treatment may trigger autophagy. Thus, excessive autophagy may stimulate the strong inflammatory response observed in the development of LPS-induced ALI. Saturated hydrogen saline may alleviate LPS-induced ALI by inhibiting autophagy, however its underlying mechanisms of action remain unknown. It has been suggested that saturated hydrogen saline may downregulate expression of nuclear factor (NF)-κB, leading to a decrease in Beclin-1 transcription and inhibition of autophagy. Inhibition of autophagy also occurs via the phosphorylation of Unc-51-like autophagy activating kinase 1 and autophagy-related protein-13 by mechanistic target of rapamycin, which in turn may be upregulated by saturated hydrogen saline. In addition, signaling pathways involving heme oxygenase-1 and p38 mitogen-activated protein kinase are associated with the alleviative effects of saturated hydrogen saline on LPS-induced autophagy. The present review focuses on potential molecular mechanisms regarding the effects of saturated hydrogen saline in the reduction of autophagy during LPS-induced ALI.

Monitoring Severity of Multiple Organ Dysfunction Syndrome: New Technologies

OBJECTIVE

To describe new technologies (biomarkers and tests) used to assess and monitor the severity and progression of multiple organ dysfunction syndrome in children as discussed as part of the Eunice Kennedy Shriver National Institute of Child Health and Human Development MODS Workshop (March 26-27, 2015).

DATA SOURCES

Literature review, research data, and expert opinion.

STUDY SELECTION

Not applicable.

DATA EXTRACTION

Moderated by an experienced expert from the field, investigators developing and assessing new technologies to improve the care and understanding of critical illness presented their research and the relevant literature.

DATA SYNTHESIS

Summary of presentations and discussion supported and supplemented by relevant literature.

CONCLUSIONS

There are many innovative tools and techniques with the potential application for the assessment and monitoring of severity of multiple organ dysfunction syndrome. If the reliability and added value of these candidate technologies can be established, they hold promise to enhance the understanding, monitoring, and perhaps, treatment of multiple organ dysfunction syndrome in children.

Mitochondrial and endoplasmic reticulum dysfunction and related defense mechanisms in critical illness-induced multiple organ failure

Patients with critical illness-induced multiple organ failure suffer from a very high morbidity and mortality, despite major progress in intensive care. The pathogenesis of this condition is complex and incompletely understood. Inadequate tissue perfusion and an overwhelming inflammatory response with pronounced cellular damage have been suggested to play an important role, but interventions targeting these disturbances largely failed to improve patient outcome. Hence, new therapeutic perspectives are urgently needed. Cellular dysfunction, hallmarked by mitochondrial dysfunction and endoplasmic reticulum stress, is increasingly recognized as an important contributor to the development of organ failure in critical illness. Several cellular defense mechanisms are normally activated when the cell is in distress, but may fail or respond insufficiently to critical illness. This insight may open new therapeutic options by stimulating these cellular defense mechanisms. This review summarizes the current understanding of the role of mitochondrial dysfunction and endoplasmic reticulum stress in critical illness-induced multiple organ failure and gives an overview of the corresponding cellular defense mechanisms. Therapeutic perspectives based on these cellular defense mechanisms are discussed. This article is part of a Special Issue entitled: Immune and Metabolic Alterations in Trauma and Sepsis edited by Dr. Raghavan Raju.

Low concentration of uncouplers of oxidative phosphorylation decreases the TNF-induced endothelial permeability and lethality in mice

Mitochondrial dysfunctions occur in many diseases linked to the systemic inflammatory response syndrome (SIRS). Mild uncoupling of oxidative phosphorylation is known to rescue model animals from pathologies related to mitochondrial dysfunctions and overproduction of reactive oxygen species (ROS). To study the potential of SIRS therapy by uncoupling, we tested protonophore dinitrophenol (DNP) and a free fatty acid (FFA) anion carrier, lipophilic cation dodecyltriphenylphosphonium (C₁₂TPP) in mice and in vitro models of SIRS. DNP and C₁₂TPP prevented the body temperature drop and lethality in mice injected with high doses of a SIRS inducer, tumor necrosis factor (TNF). The mitochondria-targeted antioxidant plastoquinonyl decyltriphenylphosphonium (SkQ1) which also catalyzes FFA-dependent uncoupling revealed similar protective effects and downregulated expression of the NFκB-regulated genes (VCAM1, ICAM1, MCP1, and IL-6) involved in the inflammatory response of endothelium in aortas of the TNF-treated mice. In vitro mild uncoupling rescued from TNF-induced endothelial permeability, disassembly of cell contacts and VE-cadherin cleavage by the matrix metalloprotease 9 (ММР9). The uncouplers prevented TNF-induced expression of MMP9 via inhibition of NFκB signaling. Water-soluble antioxidant Trolox also prevented TNF-induced activation and permeability of endothelium in vitro via inhibition of NFκB signaling, suggesting that the protective action of the uncouplers is linked to their antioxidant potential.

Distinct Myocardial Mechanisms Underlie Cardiac Dysfunction in Endotoxemic Male and Female Mice

In male mice, sepsis-induced cardiomyopathy develops as a result of dysregulation of myocardial calcium (Ca) handling, leading to depressed cellular Ca transients (ΔCai). ΔCai depression is partially due to inhibition of sarcoplasmic reticulum Ca ATP-ase (SERCA) via oxidative modifications, which are partially opposed by cGMP generated by the enzyme soluble guanylyl cyclase (sGC). Whether similar mechanisms underlie sepsis-induced cardiomyopathy in female mice is unknown.Male and female C57Bl/6J mice (WT), and mice deficient in the sGC α1 subunit activity (sGCα1), were challenged with lipopolysaccharide (LPS, ip). LPS induced mouse death and cardiomyopathy (manifested as the depression of left ventricular ejection fraction by echocardiography) to a similar degree in WT male, WT female, and sGCα1 male mice, but significantly less in sGCα1 female mice. We measured sarcomere shortening and ΔCai in isolated, externally paced cardiomyocytes, at 37°C. LPS depressed sarcomere shortening in both WT male and female mice. Consistent with previous findings, in male mice, LPS induced a decrease in ΔCai (to 30 ± 2% of baseline) and SERCA inhibition (manifested as the prolongation of the time constant of Ca decay, τCa, to 150 ± 5% of baseline). In contrast, in female mice, the depression of sarcomere shortening induced by LPS occurred in the absence of any change in ΔCai, or SERCA activity. This suggested that, in female mice, the causative mechanism lies downstream of the Ca transients, such as a decrease in myofilament sensitivity for Ca. The depression of sarcomere shortening shortening after LPS was less severe in female sGCα1 mice than in WT female mice, indicating that cGMP partially mediates cardiomyocyte dysfunction.These results suggest, therefore, that LPS-induced cardiomyopathy develops through distinct sex-specific myocardial mechanisms. While in males LPS induces sGC-independent decrease in ΔCai, in female mice LPS acts downstream of ΔCai, possibly via sGC-dependent myofilament dysfunction.

N-acetylcysteine plus deferoxamine for patients with prolonged hypotension does not decrease acute kidney injury incidence: a double blind, randomized, placebo-controlled trial

Background

The aim was to test the primary hypothesis that in patients suffering from shock, treatment with N-acetylcysteine (NAC) plus deferoxamine (DFX) decreases the incidence of acute kidney injury (AKI).

Methods

A double-blind, randomized, placebo-controlled trial was conducted in a general intensive care unit in an academic hospital. Patients were included if they had new-onset hypotension, defined as mean arterial blood pressure <60 mmHg or requirement for vasopressor medication. A loading dose of NAC or placebo of 50 mg/kg in 4 h was administered intravenously. After the loading dose, patients received 100 mg/kg/day for the next 48 h. DFX or placebo was administered once at 1000 mg at a rate of 15/mg/kg/h. The primary outcome was the incidence of AKI.

Results

A total of 80 patients were enrolled in the study. The incidence of AKI was 67 % in the placebo arm and 65 % in the treatment group (relative risk (RR) 0.89 (0.35–2.2)). Furthermore, NAC plus DFX was effective in decreasing the severity and duration of AKI, and patients in the treatment group had lower serum creatinine levels at discharge. No severe adverse event associated with treatment was reported. The effects of NAC plus DFX could be secondary to the attenuation of early inflammatory response and oxidative damage.

Conclusion

The administration of NAC plus DFX to critically ill patients who had a new episode of hypotension did not decrease the incidence of AKI.

Trial registration

Clinicaltrials.gov NCT00870883 (Registered 25 March 2009.)

Cardiac dysfunction, mitochondrial architecture, energy production, and inflammatory pathways: Interrelated aspects in endotoxemia and sepsis

Septic patients with myocardial dysfunction have a 3-fold increase in mortality compared with patients without cardiovascular impairment, and usually show myocarditis, disruption of the contractile apparatus, increased amounts of interstitial collagen, and damaged mitochondria. The presence of nitric oxide and cytokines in cardiac tissue constitute the molecular markers and the intracellular messengers of inflammatory conditions in the heart due to the onset of sepsis and endotoxemia, derived from the nuclear factor-κB pathway activation and proinflammatory gene transcription. Sepsis occurs with an exacerbated inflammatory response that damages tissue mitochondria and impaired bioenergetic processes. The heart consumes 20-30 times its own weight in adenosine triphosphate every day, and 90% of this molecule is derived from mitochondrial oxidative phosphorylation. Cardiac energy management is comprised in sepsis and endotoxemia; both a deficit in energy production and alterations in the source of energy substrates are believed to be involved in impaired cardiac function. Although several hypotheses try to explain the molecular mechanisms underlying the complex condition of sepsis and endotoxemia, the current view is that these syndromes are the result of an intricate balance between prevailing levels of mitochondrial stress, biogenesis/autophagy signaling and mitochondria quality control processes, rather on a single factor. The aim of this review is to discuss current hypothesis of cardiac dysfunction related to energy metabolism and mitochondrial function in experimental models of sepsis and endotoxemia, and to introduce the importance of lipids (mainly cardiolipin) in the mechanism of cardiac energy mismanagement in these inflammatory conditions.

Extrusion of mitochondrial contents from lipopolysaccharide-stimulated cells: Involvement of autophagy

Sepsis/endotoxemia is elicited by the circulatory distribution of pathogens/endotoxins into whole bodies, and causes profound effects on human health by causing inflammation in multiple organs. Mitochondrial damage is one of the characteristics of the cellular degeneration observed during sepsis/endotoxemia. Elimination of damaged mitochondria through the autophagy-lysosome system has been reported in the liver, indicating that autophagy should play an important role in liver homeostasis during sepsis/endotoxemia. An increased appearance of mitochondrial DNA and proteins in the plasma is another feature of sepsis/endotoxemia, suggesting that damaged mitochondria are not only eliminated within the cells, but also extruded through currently unknown mechanisms. Here we provide evidence for the secretion of mitochondrial proteins and DNA from lipopolysaccharide (LPS)-stimulated rat hepatocytes as well as mouse embryonic fibroblasts (MEFs). The secretion of mitochondrial contents is accompanied by the secretion of proteins that reside in the lumenal space of autolysosomes (LC3-II and CTSD/cathepsin D), but not by a lysosomal membrane protein (LAMP1). The pharmacological inhibition of autophagy by 3MA blocks the secretion of mitochondrial constituents from LPS-stimulated hepatocytes. LPS also stimulates the secretion of mitochondrial as well as autolysosomal lumenal proteins from wild-type (Atg5(+/+)) MEFs, but not from atg5(-/-) MEFs. Furthermore, we show that direct exposure of purified mitochondria activates polymorphonuclear leukocytes (PMNs), as evident by the induction of IL1B/interlekin-1β, a pro-inflammatory cytokine. Taken together, the data suggest the active extrusion of mitochondrial contents, which provoke an inflammatory response of immune cells, through the exocytosis of autolysosomes by cells stimulated with LPS.

Multifactorial theory applied to the neurotoxicity of paraquat and paraquat-induced mechanisms of developing Parkinson's disease

Laboratory studies involving repeated exposure to paraquat (PQ) in different animal models can induce many of the pathological features of Parkinson's disease (PD), such as the loss of dopaminergic neurons in the nigrostriatal dopamine system. Epidemiological studies identify an increased risk of developing PD in human populations living in areas where PQ exposure is likely to occur and among workers lacking appropriate protective equipment. The mechanisms involved in developing PD may not be due to any single cause, but rather a multifactorial situation may exist where PQ exposure may cause PD in some circumstances. Multifactorial theory is adopted into this review that includes a number of sub-cellular mechanisms to explain the pathogenesis of PD. The theory is placed into an environmental context of chronic low-dose exposure to PQ that consequently acts as an oxidative stress inducer. Oxidative stress and the metabolic processes of PQ-inducing excitotoxicity, α-synuclein aggregate formation, autophagy, alteration of dopamine catabolism, and inactivation of tyrosine hydroxylase are positioned as causes for the loss of dopaminergic cells. The environmental context and biochemistry of PQ in soils, water, and organisms is also reviewed to identify potential routes that can lead to chronic rates of low-dose exposure that would replicate the type of response that is observed in animal models, epidemiological studies, and other types of laboratory investigations involving PQ exposure. The purpose of this review is to synthesize key relations and summarize hypotheses linking PD to PQ exposure by using the multifactorial approach. Recommendations are given to integrate laboratory methods to the environmental context as a means to improve on experimental design. The multifactorial approach is necessary for conducting valid tests of causal relations, for understanding of potential relations between PD and PQ exposure, and may prevent further delay in solving what has proven to be an evasive etiological problem.

The histopathologic effects of L-carnitine in Sodium Taurocholate Induced Severe Pancreatitis Model

OBJECTIVE

To evaluate the histopathologic effects of L-carnitine (LC) in an experimental severe pancreatitis (SP) model induced with sodium taurocholate (STC).

SUMMARY OF BACKGROUND DATA

LC is an amino acid-like molecule that plays an active role in transporting fatty acids and producing Acetyl CoA in mitochondrial matrix for β-oxidation to provide energy which is needed for metabolism. It has ameliorative effects on cell injury demonstrated in many studies. The present study focuses on evaluating histopathologic effects of LC in an experimental SP model.

METHODS

This experimental study in rats was conducted at the Experimental Animal Research Laboratory of the Faculty of Medicine of Inonu University, Malatya, Turkey. Thirty-two Spraque-dawley male rats were divided into 4 groups in a randomized fashion: control (C) group, L-carnitine (LC) group, pancreatitis (P) group, pancreatitis and L-carnitine (P+LC) group. Pancreatitis was induced by a retrograde pancreatic duct injection of 4% sodium taurocholate and L-carnitine was administered 200 mg/kg/day in treatment group. Rats were euthanized with cardiac puncture under anesthesia at 48th hour of the experiment for biochemical and histopathological examination.

RESULTS

In (P+LC) group, the histopathological findings of the pancreatitis were markedly reduced. Acinar cell degeneration was rarely seen. Interlobular and intralobular inflammation and edema was generally mild. The pancreatic damage score of (P+LC) group was significantly lower than that of the (P) group (p<0.05).

CONCLUSION

This study revealed that l-carnitine has a significant histopathologic protective effect on acinar cell degeneration in STC-induced SP model in rats.

Broad defects in the energy metabolism of leukocytes underlie immunoparalysis in sepsis

The acute phase of sepsis is characterized by a strong inflammatory reaction. At later stages in some patients, immunoparalysis may be encountered, which is associated with a poor outcome. By transcriptional and metabolic profiling of human patients with sepsis, we found that a shift from oxidative phosphorylation to aerobic glycolysis was an important component of initial activation of host defense. Blocking metabolic pathways with metformin diminished cytokine production and increased mortality in systemic fungal infection in mice. In contrast, in leukocytes rendered tolerant by exposure to lipopolysaccharide or after isolation from patients with sepsis and immunoparalysis, a generalized metabolic defect at the level of both glycolysis and oxidative metabolism was apparent, which was restored after recovery of the patients. Finally, the immunometabolic defects in humans were partially restored by therapy with recombinant interferon-γ, which suggested that metabolic processes might represent a therapeutic target in sepsis.