Does programmed cell death (apoptosis) play a role in the development of multiple organ dysfunction in critically ill patients? a review and a theoretical framework

Inflammation, coagulation, and cellular injury in heat-induced shock

BACKGROUND

The number of heatstroke victims hit record numbers in 2022 as global warming continues. In heat-induced injuries, circulatory shock is the most severe and deadly complication. This review aims to examine the mechanisms and potential approaches to heat-induced shock and the life-threatening complications of heatstroke.

METHODS

A computer-based online search was performed using the PubMed database and Web of Science database for published articles concerning heatstroke, shock, inflammation, coagulopathy, endothelial cell, cell death, and heat shock proteins.

RESULTS

Dehydration and heat-induced cardiomyopathy were reported as the major causes of heat-induced shock, although other heat-induced injuries are also involved in the pathogenesis of circulatory shock. In addition to dehydration, the blood volume decreases considerably due to the increased vascular permeability as a consequence of endothelial damage. Systemic inflammation is induced by factors that include elevated cytokine and chemokine levels, dysregulated coagulation/fibrinolytic responses, and the release of damage-associated molecular patterns (DAMPs) from necrotic cell death that cause distributive shock. The cytoprotective heat shock proteins can also facilitate circulatory disturbance under excess heat stress.

CONCLUSIONS

Multiple mechanisms are involved in the pathogenesis of heat-induced shock. In addition to dehydration, heat stress-induced cardiomyopathy due to the thermal damage of mitochondria, upregulated inflammation via damage-associated molecular patterns released from oncotic cells, unbalanced coagulation/fibrinolysis, and endothelial damage are the major factors that are related to circulatory shock.

Alamandine alleviates hypertension and renal damage via oxidative-stress attenuation in Dahl rats

Alamandine (Ala) is a novel member of the renin-angiotensin-system (RAS) family. The present study aimed to explore the effects of Ala on hypertension and renal damage of Dahl salt-sensitive (SS) rats high-salt diet-induced, and the mechanisms of Ala on renal-damage alleviation. Dahl rats were fed with high-salt diets to induce hypertension and renal damage in vivo, and HK-2 cells were treated with sodium chloride (NaCl) to induce renal injury in vitro. Ala administration alleviated the high-salt diet-induced hypertension, renal dysfunction, and renal fibrosis and apoptosis in Dahl SS rats. The HK-2 cells' damage, and the increases in the levels of cleaved (c)-caspase3, c-caspase8, and c-poly(ADP-ribose) polymerase (PARP) induced by NaCl were inhibited by Ala. Ala attenuated the NaCl-induced oxidative stress in the kidney and HK-2 cells. DETC, an inhibitor of SOD, reversed the inhibitory effect of Ala on the apoptosis of HK-2 cells induced by NaCl. The NaCl-induced increase in the PKC level was suppressed by Ala in HK-2 cells. Notably, PKC overexpression reversed the moderating effects of Ala on the NaCl-induced apoptosis of HK-2 cells. These results show that Ala alleviates high-salt diet-induced hypertension and renal dysfunction. Ala attenuates the renal damage via inhibiting the PKC/reactive oxygen species (ROS) signaling pathway, thereby suppressing the apoptosis in renal tubular cells.

Role of pro-inflammatory cytokines in the pathophysiology of herpes simplex virus superinfection in Darier's disease

Darier's disease (DD) and Hailey-Hailey disease (HHD), belonging to a hereditary acantholytic dermatosis caused by mutations in ATP2A2 and ATP2C1, respectively, are easily affected by eczema herpeticum (EH) induced by mostly herpes simplex virus (HSV) superinfection. However, the mechanisms by which those patients with DD or HHD are susceptible to HSV are not well elucidated. Here, we experienced two cases with DD, including three episodes of the exacerbation of DD after the development of severe EH. We serially measured serum cytokines before and after the development of EH and DD in these patients. Furthermore, we analyzed the effect of pro-inflammatory cytokines on the mRNA expression of ATP2A2 and ATP2C1, and HSV growth. The timing of EH onset in these patients was coincident with the increase in serum interleukin (IL)-6 and tumor necrosis factor (TNF)-α levels. Moreover, the exacerbation of DD occurred in the non-lesional skin of EH after EH remission (mean 24 days, ranging 15-30 days after EH onset). IL-6 and TNF-α enhanced HSV-1 growth, and ATP2A2 and ATP2C1 mRNA levels were downregulated by IL-6 stimulation in cultured differentiated keratinocytes. Increased pro-inflammatory cytokines IL-6 and TNF-α lead to development of severe EH lesions via accentuation of HSV growth. IL-6 acts as an exacerbating factor of DD and HHD by downregulating the expression of responsible genes.

Impact of Postoperative Complications on Long-Term Survival After Resection of Hepatocellular Carcinoma: A Systematic Review and Meta-Analysis

BACKGROUND

Controversy exists over the relationship between postoperative complications (POCs) and long-term survival for hepatocellular carcinoma (HCC) after hepatectomy. This study aimed to evaluate the impact of POCs on overall survival (OS) and disease-free survival (DFS) for HCC after liver resection.

PATIENTS AND METHODS

The PubMed, EMBASE, and Cochrane Library databases were used to search for eligible studies published through 18 April 2020, and studies comparing the long-term outcomes between HCC patients with and without POCs after hepatectomy were included. A random-effects model was used to calculate the pooled hazard ratio (HR) with a 95% confidence interval (CI). Subgroup analysis and meta-regression were performed to assess the potential influence of study-, patient-, and tumor-related factors on the relationship between POCs and oncologic outcomes and to adjust their effect. This study was registered at the International Prospective Register of Systematic Reviews (CRD42019136109).

RESULTS

Thirty-seven studies, including 14,096 patients, were deemed eligible and included in this study. Compared with those without POCs, patients who developed POCs had a significant reduction in OS (HR 1.39, 95% CI 1.28-1.50, P < 0.001; prediction interval 1.04-1.85) and tended to have worse DFS (HR 1.25, 95% CI 1.16-1.35, P < 0.001; prediction interval 0.98-1.60). Contour-enhanced funnel plots suggested a risk of publication bias. Subgroup analysis and meta-regression showed that POCs remained a threat to OS and DFS regardless of the influence of clinicopathological factors.

CONCLUSION

This study demonstrated that POCs had an adverse impact on OS and DFS in HCC patients after liver resection.

Paediatrics: how to manage septic shock

Background

Septic shock is a common critical illness associated with high morbidity and mortality in children. This article provides an updated narrative review on the management of septic shock in paediatric practice.

Methods

A PubMed search was performed using the following Medical Subject Headings: "sepsis", "septic shock" and "systemic inflammatory response syndrome". The search strategy included meta-analyses, randomized controlled trials, clinical trials, observational studies and reviews. The search was limited to the English literature and specific to children.

Results

Septic shock is associated with high mortality and morbidity. The outcome can be improved if the diagnosis is made promptly and treatment initiated without delay. Early treatment with antimicrobial therapy, fluid therapy and vasoactive medications, and rapid recognition of the source of sepsis and control are the key recommendations from paediatric sepsis management guidelines.

Conclusion

Most of the current paediatric sepsis guideline recommendations are based on the adult population; therefore, the research gaps in paediatric sepsis management should be addressed.

Association of Plasma Levels of FAS Ligand with Severity and Outcome of Sepsis

INTRODUCTION

Levels of the apoptosis regulator Fas ligand (FasL) are associated with severity of sepsis, but its association with the mortality of sepsis and necroptosis, a regulated cell death mechanism, is not yet clear. We aimed to assess the association of FasL level with outcomes of sepsis and receptor interacting protein kinase-3 (RIPK3), an essential necroptosis mediator, for determining the relationship between FasL and necroptosis.

METHODS

Plasma FasL and RIPK3 levels were measured by ELISA from prospectively enrolled critically-ill adult patients. The best cut-off level of FasL for 28-day mortality prediction was determined by Youden's index. The association between plasma levels of FasL and RIPK3 was assessed by a linear regression method.

RESULTS

Among 188 patients, 58 (30.9%) were diagnosed with sepsis and 84 (44.7%) with septic shock, respectively. Plasma levels of FasL increased in the group order of control, sepsis, and septic shock groups (P for trend < 0.001). For 142 patients with sepsis, organ dysfunction and septic shock were more prevalent in the group with plasma FasL levels that were higher than the best cut-off level. A significant difference in mortality between high and low FasL patients was observed up to 90 days (Log-rank P = 0.013). FasL levels did not significantly change over day 3 and day 7. FasL levels were not correlated with those of RIPK3.

CONCLUSIONS

The plasma level of FasL was associated with severity of sepsis and was predictive of mortality. However, it was not correlated with RIPK3 level.

Multiple organ dysfunction syndrome: Contemporary insights on the clinicopathological spectrum

Multiorgan dysfunction syndrome (MODS) remains a major complication and challenge to treat patients with critical illness in different intensive care unit settings. The exact mechanism and pathophysiology of MODS is complex and remains unexplored. We reviewed the literature from January 2011 to August 2019 to analyze the underlying mechanisms, prognostic factors, MODS scoring systems, organ systems dysfunctions, and the management of MODS. We used the search engines PubMed, MEDLINE, Scopus, and Google Scholar with the keywords "multiple organ dysfunction syndrome," "intensive care units," "multiorgan failure," "MODS scoring system," and "MODS management." The initial search yielded 3550 abstracts, of which 91 articles were relevant to the scope of the present article. A better understanding of a disease course will help differentiate the signs of an intense inflammatory response from the early onset of sepsis and minimize the inappropriate use of medications. This, in turn, will promote organtargeted therapy and prevent occurrence and progression of MODS.

Phagocytosis-Inflammation Crosstalk in Sepsis: New Avenues for Therapeutic Intervention

Phagocytosis is a complex process by which cells within most organ systems remove pathogens and cell debris. Phagocytosis is usually followed by inflammatory pathway activation, which promotes pathogen elimination and inhibits pathogen growth. Delayed pathogen elimination is the first step in sepsis development and a key factor in sepsis resolution. Phagocytosis thus has an important role during sepsis and likely contributes to all of its clinical stages. However, only a few studies have specifically explored and characterized phagocytic activity during sepsis. Here, we describe the phagocytic processes that occur as part of the immune response preceding sepsis onset and identify the elements of phagocytosis that might constitute a predictive marker of sepsis outcomes. First, we detail the key features of phagocytosis, including the main receptors and signaling hallmarks associated with different phagocytic processes. We then discuss how the initial events of phagosome formation and cytoskeletal remodeling might be associated with known sepsis features, such as a cytokine-driven hyperinflammatory response and immunosuppression. Finally, we highlight the unresolved mechanisms of sepsis development and progression and the need for cross-disciplinary approaches to link the clinical complexity of the disease with basic cellular and molecular mechanisms.

miR-1247-3p mediates apoptosis of cerebral neurons by targeting caspase-2 in stroke

Brain stroke is one of the leading causes of death worldwide. We explored a potential stroke-related role for a newly found microRNA, miR-1247-3p, and one of its target genes, caspase-2, predicted by TargetScanVert. In the present study, we found that miR-1247-3p was downregulated during ischemia/reperfusion (I/R) and that LV-miR-1247-3p overexpression attenuated brain impairment induced by I/R. Similar results were observed in neuro2a (N2a) cells treated with oxygen-glucose deprivation/reoxygenation (OGD/R). Caspase-2 was upregulated in the I/R and OGD/R model, while Z-VDVAD-FMK - the inhibitor of caspase-2-inhibited apoptosis of N2a cells induced by OGD/R. An miR-1247-3p mimic inhibited caspase-2 expression and attenuated apoptosis of N2a cells induced by OGD/R. Myocardin-related transcription factor-A (MRTF-A) overexpression upregulated miR-1247 and mature miR-1247-3p levels and attenuated apoptosis induced by OGD/R, whereas its anti-apoptotic function could be blocked by a miR-1247-3p inhibitor. Hence, we conclude that miR-1247-3p may protect cells during brain stroke. This study offers insights for the development of effective therapeutics for promoting the survival of cerebral neurons during brain I/R injury.

FSAP, a new player in inflammation?

Factor VII-activating protease (FSAP) is a serine protease in plasma that has a role in coagulation and fibrinolysis. FVII could be activated by purified FSAP in a tissue factor independent manner and pro-urokinase has been demonstrated to be a substrate for purified FSAP in-vitro. However, the physiological role of FSAP in haemostasis remains unclear. More recently FSAP is suggested to be involved in inflammation. It modulates vascular permeability directly and indirectly by the generation of bradykinin. Furthermore, FSAP is activated by dead cells induced by the inflammatory response and subsequently removes nucleosomes from apoptotic cells. FSAP activation can be detected in sepsis patients as well. However, whether FSAP activation upon inflammation is beneficial or detrimental remains an open question.

In this review the structure, activation mechanisms and the possible role of FSAP in inflammation are discussed.

Deficiency in cold-inducible RNA-binding protein attenuates acute respiratory distress syndrome induced by intestinal ischemia-reperfusion

BACKGROUND

Intestinal ischemia-reperfusion can occur in shock and mesenteric occlusive diseases, causing significant morbidity and mortality. Aside from local injury, intestinal ischemia-reperfusion can result in remote organ damage, particularly in the lungs. Cold-inducible RNA-binding protein (CIRP) was identified as a novel inflammatory mediator. We hypothesized that a deficiency in CIRP would protect the lungs during intestinal ischemia-reperfusion injury.

METHODS

Intestinal ischemia was induced in adult male C57BL/6 wild-type and CIRP knock-out (CIRP^-/-) mice via clamping of the superior mesenteric artery for 60 minutes. Reperfusion was allowed for 4 hours or 20 hours, and blood, gut, and lung tissues were harvested for various analyses.

RESULTS

After intestinal ischemia-reperfusion, the elevated levels of serum lactate dehydrogenase and inflammatory cytokine interleukin-6 were reduced by 68% and 98%, respectively, at 20 hours after ischemia-reperfusion in CIRP^-/- mice compared with the wild-type mice. In the gut, mRNA levels of inflammatory cytokine interleukin-6 were reduced by 67% at 4 hours after ischemia-reperfusion in CIRP^-/- mice. In the lungs, inflammatory cytokine interleukin-6 protein and myeloperoxidase activity were reduced by 78% and 26% at 20 hours and 4 hours after ischemia-reperfusion, respectively, in CIRP^-/- mice. Finally, the elevated lung caspase-3 was significantly decreased by 55%, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling-positive cells decreased by 91%, and lung injury score decreased by 37% in CIRP^-/- mice at 20 hours after ischemia-reperfusion.

CONCLUSION

Increased levels of proinflammatory cytokines, myeloperoxidase, and apoptosis are the hallmarks of acute respiratory distress syndrome. We noticed after intestinal ischemia-reperfusion the proinflammatory milieu in lungs was elevated significantly, while the CIRP^-/- mice had significantly decreased levels of proinflammatory cytokine, myeloperoxidase, and apoptotic cells leading to decreased lung injury. These findings strongly established a causal link between CIRP and acute respiratory distress syndrome during intestinal ischemia-reperfusion injuries. Targeting CIRP may therefore be beneficial for treatment of intestinal ischemia-reperfusion-associated acute respiratory distress syndrome acute respiratory distress syndrome.

Critical Care Medicine: Major Changes in Dogma of the Past Decade

Critical care medicine is a young specialty that has experienced an expansion of research efforts in the last decade. Many physiologic and therapeutic principles or “dogmas” have been challenged, resulting in major “shifts” and minor “drifts” in thinking. This article reviews the available literature about some of these important and sometimes controversial changes, with emphasis on the practical implications of the concepts. Specific areas discussed include supply-dependent oxygen consumption in critical illness, manipulation of the cytokine cascade in sepsis, ventilation in the acute respiratory distress syndrome (ARDS), blood transfusion in the critically ill, the concept of the multiple organ dysfunction syndrome (MODS), the need for nutritional support in the critically ill, and others. Many of the changes discussed involve the recognition that the host response to a severe insult is exceedingly complex, and the understanding of this response and the effects of it at a tissue and cellular level are incomplete. As a result, the ability to impact the outcome of sepsis and MODS has thus far been disappointing, with the possible exception of “lung-protective” ventilation. The final challenge in critical care medicine is to gain information that will allow the practitioner to better understand, prevent, and treat the complex events that result in organ and cellular dysfunction. Future changes in dogma are welcome if they help achieve these goals.

Blockade of PKCβ protects against remote organ injury induced by intestinal ischemia and reperfusion via a p66shc-mediated mitochondrial apoptotic pathway

Intestinal ischemia-reperfusion (I/R) is a serious clinical dilemma with high morbidity and mortality. Remote organ damage, especially acute lung injury and liver injury are common complications that contribute to the high mortality rate. We previously demonstrated that activation of PKCβII is specifically involved in the primary injury of intestinal I/R. Considering the tissue-specific features of PKC activation, we hypothesized that some kind of PKC isoform may play important roles in the progression of secondary injury in the remote organ. Mice were studied in in vivo model of intestinal I/R. The activation of PKC isoforms were screened in the lung and liver. Interestingly, we found that PKCβII was also activated exclusively in the lung and liver after intestinal I/R. PKCβII suppression by a specific inhibitor, LY333531, significantly attenuated I/R-induced histologic damage, inflammatory cell infiltration, oxidative stress, and apoptosis in these organs, and also alleviated systemic inflammation. In addition, LY333531 markedly restrained p66shc activation, mitochondrial translocation, and binding to cytochrome-c. These resulted in the decrease of cytochrome-c release and caspase-3 cleavage, and an increase in glutathione and glutathione peroxidase. These data indicated that activated PKC isoform in the remote organ, specifically PKCβII, is the same as that in the intestine after intestinal I/R. PKCβII suppression protects against remote organ injury, which may be partially attributed to the p66shc-cytochrome-c axis. Combined with our previous study, the development of a specific inhibitor for prophylaxis against intestinal I/R is promising, to prevent multiple organ injury.

Paeoniflorin reduced BLP-induced inflammatory response by inhibiting the NF-κB signal transduction in pathway THP-1 cells

Sepsis is a severe illness in which the bloodstream is overwhelmed by bacteria. Despite effective antibiotic treatment, the mortality of septic shock remains high. In this study, we examined a potential usage of paeoniflorin, anti-inflammatory component for the treatment of sepsis. We established an inflammatory cell line by stimulating human THP-1 cell line with bacterial lipoprotein (BLP), which resulted in an activation of nuclear factor κB (NF-κB) p65 dependent-signal pathway, and in consequence, an increase in tumor necrosis factor α (TNF-α) and interleukin (IL)-6 expression. With this model, we studied the effect of paeoniflorin on the expression of NF-κB and Toll-like receptor 2 (TLR2) mediated signal transduction. Our data indicated that paeoniflorin directly inhibited activation of NF-κB p65, thereby reduced the expression of TNF-α and IL-6 in the BLP stimulated THP-1 cells. Paeoniflorin was also found to inhibit IκB phosphorylation and degradation. However, no significant differences in TLR2 and myeloid differentiation factor 88 (MyD88) expression were observed; therefore, these signaling molecules may not have much anti-inflammatory effect in our cellular model. As such, our current study provided a molecular base for the potential use of paeoniflorin in therapeutic treatment of sepsis induced by bacterial lipoprotein.

Nonhematopoietic β-Arrestin-1 inhibits inflammation in a murine model of polymicrobial sepsis

β-Arrestin-1 (βArr1), a scaffolding protein critical in G-protein coupled receptor desensitization has more recently been found to be important in the pathogenesis of various inflammatory diseases. We sought to understand the role of βArr1 in sepsis pathogenesis using a mouse model of polymicrobial sepsis. Although in previous studies we established that βArr1 deficiency protects mice from endotoxemia, here we demonstrate that the absence of βArr1 remarkably renders mice more susceptible to mortality in polymicrobial sepsis. In accordance with the mortality pattern, early production of inflammatory mediators was markedly enhanced in βArr1 knockout mice systemically and locally in various organs. In addition, enhanced inflammation in the heart was associated with increased NFκB activation. Compared to these effects, immune cell infiltration, thymic apoptosis, and immune suppression during polymicrobial sepsis were unaffected by a deficiency of βArr1. Additionally, enhanced inflammation and consequent higher mortality were not observed in heterozygous mice, suggesting that one allele of βArr1 was sufficient for this protective negative regulatory role. We further demonstrate that, unexpectedly, βArr1 in nonhematopoietic cells is critical and sufficient for inhibiting sepsis-induced inflammation, whereas hematopoietic βArr1 is likely redundant. Taken together, our results reveal a novel and previously unrecognized negative regulatory role of the nonhematopoietic βArr1 in sepsis-induced inflammation.

The long-term effects of postoperative complications

PURPOSE OF REVIEW

This review examines the long-term influence of postoperative complications on survival. Although it is intuitive that complications after surgery worsen short-term outcomes, it is not clear to what extent and why a longer-term relationship may exist.

RECENT FINDINGS

Most studies have focused on outcomes after cancer surgery. Despite mixed results in smaller cohorts, large multicentre analyses consistently identify an association between postoperative complications and long-term mortality. In part, this phenomenon may be due to unmeasured confounding factors or insufficient separation of short and long-term consequences. Nevertheless, functional and biological imprints established during postoperative complications are likely to be relevant, and are the subject of ongoing research.

SUMMARY

Patients that develop postoperative complications and survive the immediate risk period, demonstrate worsened long-term mortality. The field of perioperative medicine is increasingly mandated to identify vulnerable individuals, develop and implement strategies to prevent and treat complications, and provide better care pathways after hospital discharge.

The role of protein C in sepsis

During the past 15 years, several anti-inflammatory treatments have failed to reduce mortality in patients with severe sepsis. However, recent evidence indicates that coagulation abnormalities in sepsis may play a major role in the pathogenesis of multiple organ failure and the high mortality rate in patients with severe sepsis. Interestingly, blockade of the coagulant pathway can inhibit both procoagulant and proinflammatory pathways in sepsis. Protein C, a natural anticoagulant, interrupts several of the pathophysiologic pathways in sepsis. Acquired protein C deficiency is present in the majority of septic patients and is associated with unfavorable outcomes. Protein C replacement therapy was effective in preclinical animal models of sepsis in reducing end-organ damage and mortality. Recent clinical trials of protein C replacement in human meningococcemia resulted in a markedly decreased morbidity and mortality. And, most importantly, in a recently completed large, randomized trial of activated protein C treatment in severe sepsis, mortality was reduced from 30.8% in the placebo group to 24.7% in the treatment group at 28 days. Thus, there is new evidence that mortality can be reduced among patients with severe sepsis through the use of a new therapy that inhibits the procoagulant and the inflammatory cascades.

Early trauma-hemorrhage-induced splenic and thymic apoptosis is gut-mediated and toll-like receptor 4-dependent

Immune depression after trauma-hemorrhage has been implicated as an important factor in the pathogenesis of sepsis and septic-organ failure. Although recent studies have implicated immune-cell apoptosis as an important factor in the evolution of this posttrauma immune-suppressed state, neither the initial triggers that induce this response nor the cellular pathways through which these triggering pathways act have been fully defined. Thus, the current study tests the hypothesis that acute splenic and thymic immune-cell apoptosis developing after trauma-hemorrhagic shock (T/HS) is due to gut-derived factors carried in intestinal lymph and that this T/HS lymph-induced immune depressed state is mediated through Toll-like receptor 4 (TLR4). The first set of experiments documented that T/HS caused both thymic and splenic immune-cell apoptosis as measured by TUNEL (terminal deoxynucleotidyl transferase dUTP nick end labeling) and caspase-3 immunohistochemistry and that this increase in apoptosis was totally abrogated by mesenteric lymph duct ligation. In subsequent experiments, mesenteric lymph collected from animals subjected to T/HS or trauma-sham shock were injected into TLR4-deficient (TLR4mut) mice or their wild-type (WT) littermates. Trauma-hemorrhagic shock, but not trauma-sham shock, lymph caused splenic apoptosis in the WT mice. However, the TLR4mut mice were resistant to T/HS lymph-induced splenic apoptosis. Furthermore, the WT, but not the TLR4mut mice developed splenic apoptosis after actual T/HS. In conclusion, gut-derived factors appear to initiate a sequence of events that leads to an acute increase in splenic and thymic immune-cell apoptosis, and this process is TLR4-dependent.

Impact of fluid therapy on apoptosis and organ injury during haemorrhagic shock in an oxygen-debt-controlled pig model

INTRODUCTION

Apoptosis, or programmed cell death, seems to play a role in the physiology of shock. The influence of fluid resuscitation on the occurrence of apoptosis during haemorrhage is still unclear. Using an experimental randomised study, the goal of this investigation was to find a relation between different frequently used resuscitation fluids and evidence of apoptosis.

MATERIALS AND METHODS

Sixty female pigs with a mean body weight of 20 kg were randomised into six groups, each receiving a different resuscitation fluid therapy: malated Ringer, lactated Ringer, hypertonic saline, hypertonic saline solution/Dextran 60, carbonate/gelatine and a sham group (no shock, no resuscitation). A haemorrhagic shock with a predefined oxygen debt with high mortality expected was induced for a period of 60 min. Then, the resuscitation fluid therapy within each group was initiated. At the beginning, after 1 h of shock and 1 and 2 h after resuscitation, biopsies from the liver were taken, as one of the most important metabolism organs of shock. Three hours after the beginning of the resuscitation period, the animals were allowed to recover under observation for 3 days. At the end of this period, a state of narcosis was induced and another liver biopsy was taken. Finally, the animals were sacrificed and samples were taken from the liver, kidney, heart and hippocampus. The TUNEL method was used for identifying apoptosis. Impairment of liver function was indicated by the measurement of transaminase levels.

RESULTS

There was no observed difference in the rate of apoptosis in all groups and a low number of apoptotic cells were found in all the organs sampled. The sham group also showed a low count of apoptosis. The hypoxia-sensitive neurons within the hippocampus did not show any signs of apoptosis. The high oxygen debt during haemorrhage led to a high mortality. The non-treated animals died very quickly, as an indicator for severe shock. Animals treated with hypertonic saline showed a significant increase in aspartate transaminase (AST) plasma levels on the first day after shock.

CONCLUSION

The different resuscitation fluids used in the treatment of haemorrhagic shock in this experimental model showed no evidence of a different apoptosis rate in the end organs.

Survival in Critically Ill Patients with Acute Kidney Injury Treated with Early Hemodiafiltration

Purpose

Early renal replacement therapy (RRT) initiation should theoretically influence many physiological disorders related to acute kidney injury (AKI). Currently, there is no consensus about RRT timing in intensive care unit (ICU) patients.

Methods

We performed a retrospective analysis of all critically ill patients who received RRT in our ICU during a 3 year-period. Our goal was to identify mortality risk factors and if RRT initiation timing had an impact on survival. RRT timing was calculated from the moment the patient was classified as having acute kidney injury in the RIFLE classification.

Results

A hundred and ten patients received RRT. We identified four independent mortality risk factors: need for mechanical ventilation (OR = 12.82 (1.305 - 125.868, p = 0.0286); RRT initiation timing >16 h (OR = 5.66 (1.954 - 16.351), p = 0.0014); urine output on admission <500 ml/day (OR = 4.52 (1.666 - 12.251), p = 0.003); and SAPS II on admission >70 (OR = 3.45 (1.216 - 9.815), p = 0.02). The RRT initiation <16 h and RRT initiation >16 h groups presented the same baseline characteristics, except for more severe gravity scores and kidney failure in the early RRT group.

Conclusions

Early RRT in ICU patients with acute kidney injury or failure was associated with increased survival.

Post-cardiac arrest syndrome: Mechanisms and evaluation of adrenal insufficiency

Cardiac arrest is one of the leading causes of death and represents maximal stress in humans. After restoration of spontaneous circulation, post-cardiac arrest syndrome is the predominant disorder in survivors. Besides the post-arrest brain injury, the post-resuscitation myocardial stunning, and the systemic ischemia/reperfusion response, this syndrome is characterized by adrenal insufficiency, a disorder that often remains undiagnosed. The pathophysiology of adrenal insufficiency has not been elucidated. We performed a comprehensive search of three medical databases in order to describe the major pathophysiological disturbances which are responsible for the occurrence of the disorder. Based on the available evidence, this article will help physicians to better evaluate and understand the hidden yet deadly post-cardiac arrest adrenal insufficiency.

Progression of apoptic signaling from mesenteric ischemia-reperfusion injury to lungs: correlation in the level of ER chaperones expression

Multiple organ dysfunction syndrome (MODS) is characterized by the development of probably reversible, progressive dysfunction of vital systems in two or more organs, directly undamaged by surgery or other trauma. The organs which have the most common potential dysfunction are lungs, liver, kidneys, heart and gastrointestinal tract. The small intestine is the source of production of proinflammatory mediators leading and contributing to multiorgan failure. The endoplasmic reticulum (ER), after ischemia and post-ischemic reperfusion, is significantly involved in the activation of enterocyte apoptosis. The purpose of this study was to determine the stage of apoptosis in the lungs, initiated through inflammatory response from the small intestine. We analyzed changes in mRNA levels of pro-apoptotic genes Gadd153 (Chop) and anti-apoptotic genes Grp78 (Bip) in the small intestine wall and lung parenchyma. During experimental procedure the rats underwent 60 min of ischemia, caused by complete occlusion of the mesenteric arteria cranialis, with subsequent reperfusion and evaluation after 1 h, 24 h and 30 days (from R1, R24 to R30, respectively, each group n = 8). The gene expression levels were measured using RT-PCR followed by electrophoresis and visualization under UV. In the lungs we detected significantly lower level of expression Grp78 by 45 ± 6.9%. This suggests that ischemic attack and subsequent reperfusion did not promote ER stress in the lungs through induction of Gadd153 expression in the small intestine. There is still no effective approach to the treatment of affected ischemic intestine tissue, to stop the processes with could eventually lead to MODS. Therefore it is necessary to study changes in the damaged tissue at the molecular level and try to suggest possible therapeutic defined routes to the protection of tissue.

Use of physiologic reasoning to diagnose and manage shock States

Shock states are defined by stereotypic changes in well-known physiologic parameters. While these well-known changes provide a convenient entry point into further evaluation of patients in shock or at risk for shock, use of such physiologic evaluation is not commonly seen in clinical medicine. A formal description of physiologic reasoning in the diagnosis of shock states is presented in this paper. Included with this conceptual framework is a discussion of key tests or findings that can be used to differentiate between possible diagnoses, and the pairing of treatment strategies to distinct classes of physiologic abnormalities. It is hoped that the methodology presented here will demonstrate the primacy of physiologic reasoning in the diagnosis and treatment of hemodynamic instability. Advantages of this method are speed and accuracy, efficient use of resources, and mitigation against sources of medical errors.

Fatal outcome in bacteremia is characterized by high plasma cell free DNA concentration and apoptotic DNA fragmentation: a prospective cohort study

INTRODUCTION

Recent studies have shown that apoptosis plays a critical role in the pathogenesis of sepsis. High plasma cell free DNA (cf-DNA) concentrations have been shown to be associated with sepsis outcome. The origin of cf-DNA is unclear.

METHODS

Total plasma cf-DNA was quantified directly in plasma and the amplifiable cf-DNA assessed using quantitative PCR in 132 patients with bacteremia caused by Staphylococcus aureus, Streptococcus pneumoniae, ß-hemolytic streptococcae or Escherichia coli. The quality of cf-DNA was analyzed with a DNA Chip assay performed on 8 survivors and 8 nonsurvivors. Values were measured on days 1-4 after positive blood culture, on day 5-17 and on recovery.

RESULTS

The maximum cf-DNA values on days 1-4 (n = 132) were markedly higher in nonsurvivors compared to survivors (2.03 vs 1.26 ug/ml, p<0.001) and the AUCROC in the prediction of case fatality was 0.81 (95% CI 0.69-0.94). cf-DNA at a cut-off level of 1.52 ug/ml showed 83% sensitivity and 79% specificity for fatal disease. High cf-DNA (>1.52 ug/ml) remained an independent risk factor for case fatality in a logistic regression model. Qualitative analysis of cf-DNA showed that cf-DNA displayed a predominating low-molecular-weight cf-DNA band (150-200 bp) in nonsurvivors, corresponding to the size of the apoptotic nucleosomal DNA. cf-DNA concentration showed a significant positive correlation with visually graded apoptotic band intensity (R = 0.822, p<0.001).

CONCLUSIONS

Plasma cf-DNA concentration proved to be a specific independent prognostic biomarker in bacteremia. cf-DNA displayed a predominating low-molecular-weight cf-DNA band in nonsurvivors corresponding to the size of apoptotic nucleosomal DNA.

Activation of factor VII-activating protease in human inflammation: a sensor for cell death

INTRODUCTION

Cell death is a central event in the pathogenesis of sepsis and is reflected by circulating nucleosomes. Circulating nucleosomes were suggested to play an important role in inflammation and were demonstrated to correlate with severity and outcome in sepsis patients. We recently showed that plasma can release nucleosomes from late apoptotic cells. Factor VII-activating protease (FSAP) was identified to be the plasma serine protease responsible for nucleosome release. The aim of this study was to investigate FSAP activation in patients suffering from various inflammatory diseases of increasing severity.

METHODS

We developed ELISAs to measure FSAP-C1-inhibitor and FSAP-α2-antiplasmin complexes in plasma. FSAP-inhibitor complexes were measured in the plasma of 20 adult patients undergoing transhiatal esophagectomy, 32 adult patients suffering from severe sepsis and 8 from septic shock and 38 children suffering from meningococcal sepsis.

RESULTS

We demonstrate plasma FSAP to be activated upon contact with apoptotic and necrotic cells by an assay detecting complexes between FSAP and its target serpins α2-antiplasmin and C1-inhibitor, respectively. By means of that assay we demonstrate FSAP activation in post-surgery patients, patients suffering from severe sepsis, septic shock and meningococcal sepsis. Levels of FSAP-inhibitor complexes correlate with nucleosome levels and correlate with severity and mortality in these patients.

CONCLUSIONS

These results suggest FSAP activation to be a sensor for cell death in the circulation and that FSAP activation in sepsis might be involved in nucleosome release, thereby contributing to lethality.

The grade-response relation between severity of peritonitis and serum cytokine concentrations explains Mannheim Peritonitis Index threshold

AIM

To explore the gradient between the acute-phase response (APR) and peritonitis of differing severity.

METHODS

In 202 patients with peritonitis, we determined serum concentrations of interleukin (IL)-6, IL-10, IL-13, tumor necrosis factor (TNF)-alpha, and C-reactive protein (CRP). The severity of peritonitis was graded in accordance with the Mannheim Peritonitis Index (MPI). The grade-response relation between the severity of peritonitis and each analyte was explored.

RESULTS

A statistically significant association was found between the medians of severity of peritonitis and IL-6 (p < 0.025), TNF-alpha (p < 0.01), CRP (p < 0.033), IL-10 (p < 0.0001), and IL-13 (p < 0.004). Both TNF-alpha and IL-10 had a direct, and IL-13 an indirect, relation to severity, whereas CRP and IL-6 tended toward linear behavior in equilibrium. A significant association persisted between individual MPI scores and IL-6 (p < 0.002), TNF-alpha (p < 0.002), CRP (p < 0.002), and IL-10 (p < 0.001), but not IL-13 (p = 0.646).

CONCLUSION

Around the mean value of grade II peritonitis, the equilibrium between pro-inflammatory and anti-inflammatory cytokines is lost. This change coincides with the 26-point threshold for the MPI.

Pharmacotherapy for prevention and treatment of acute respiratory distress syndrome: current and experimental approaches

The acute respiratory distress syndrome (ARDS) arises from direct and indirect injury to the lungs and results in a life-threatening form of respiratory failure in a heterogeneous, critically ill patient population. Critical care technologies used to support patients with ARDS, including strategies for mechanical ventilation, have resulted in improved outcomes in the last decade. However, there is still a need for effective pharmacotherapies to treat ARDS, as mortality rates remain high. To date, no single pharmacotherapy has proven effective in decreasing mortality in adult patients with ARDS, although exogenous surfactant replacement has been shown to reduce mortality in the paediatric population with ARDS from direct causes. Several promising therapies are currently being investigated in preclinical and clinical trials for treatment of ARDS in its acute and subacute, exudative phases. These include exogenous surfactant therapy, β₂-adrenergic receptor agonists, antioxidants, immunomodulating agents and HMG-CoA reductase inhibitors (statins). Recent research has also focused on prevention of acute lung injury and acute respiratory distress in patients at risk. Drugs such as captopril, rosiglitazone and incyclinide (COL-3), a tetracycline derivative, have shown promising results in animal models, but have not yet been tested clinically. Further research is needed to discover therapies to treat ARDS in its late, fibroproliferative phase. Given the vast number of negative clinical trials to date, it is unlikely that a single pharmacotherapy will effectively treat all patients with ARDS from differing causes. Future randomized controlled trials should target specific, more homogeneous subgroups of patients for single or combination therapy.

[Acute perioperative disturbances of renal function. Strategies for prevention and therapy]

The increasing life expectancy in industrial nations leads to an increase in the number of elderly and aged persons treated in hospital. Increasingly more complex operations are being carried out on this group of patients. Renal dysfunction in the preoperative situation increases morbidity and mortality. Acute kidney injury (AKI) is nearly always part of a multi-organ dysfunction syndrome in critically ill patients. The treatment strategy of the AKI should be oriented to the degree of organ dysfunction. However, the stage of organ dysfunction is mostly unknown so that the therapeutically exploitable interval is often missed. The same therapy is practically always used for all patients: administration of fluids and diuretics often under the premise of "the kidneys must be rinsed". A unified classification of the continuation of kidney function disorders using the RIFLE criteria (risk, injury, failure, loss, endstage kidney disease) can assist recognition of early stages of kidney failure in order to react correspondingly with therapeutic measures and to critically question or optimize the use of conservative treatment strategies.

Compartmental apoptosis and neutrophil accumulation in severe peritonitis

BACKGROUND

Migration and activation of polymorphonuclear neutrophils (PMN) and apoptosis are central to inflammatory tissue damage. This study examines the relation of these processes, and their expression in the abdominal, systemic, and bronchoalveolar compartments in patients with severe peritonitis.

MATERIALS AND METHODS

Thirty-one consecutive patients undergoing laparotomy for severe secondary peritonitis. Eight operated patients without peritonitis and 10 long-term mechanically ventilated noninfected patients served as controls. Peritoneal fluid, blood, and bronchoalveolar lavage fluid (BALF) was obtained on d 0 (day of initial laparotomy), 2, and 3. Levels of chemokines (interleukin (IL)-8 and monocyte chemotactic protein (MCP)-1), PMN-counts, PMN activation [myeloperoxidase (MPO), elastase] and apoptosis (nucleosomes) were determined.

RESULTS

In peritonitis patients, levels of chemokines and markers of PMN sequestration were increased in all compartments. IL-8 levels were higher in BALF than in plasma, and did not originate from the circulation or from lysis of alveolar cells. Pulmonary nucleosome levels were higher in patients who died (P=0.020), and corresponded with PMN-count in BALF (P<0.001), levels of chemokines (IL-8, P=0.003; MCP-1, P=0.001), and PMN-activation (MPO, P<0.001; elastase P=0.007).

CONCLUSION

Severe peritonitis produces an early pulmonary expression of chemoattractants creating a gradient for PMN sequestration and activation into the lung. These parameters are associated with expression of apoptosis in the lung, which is increased in nonsurviving peritonitis patients.

Uncoupling protein-2 deficiency provides protection in a murine model of endotoxemic acute liver failure

OBJECTIVE

Liver injury and cell death are prominent features in the pathogenesis of acute liver failure. Mitochondrial uncoupling protein 2 plays a controversial role in liver cell death through its involvement in the production of reactive oxygen species and adenosine triphosphate.

DESIGN

This randomized controlled animal study was designed to investigate the exact role of uncoupling protein 2 in the pathogenesis of endotoxemic acute liver failure.

SETTING

Research laboratory of an academic institution. SUBJECTS, INTERVENTIONS, AND MEASUREMENTS: Uncoupling protein 2+/+ and uncoupling protein 2-/- mice were challenged with D-galactosamine (Gal, 720 mg/kg intraperitoneally) and Escherichia coli lipopolysaccharide (10 microg/kg intraperitoneally) and studied 6 hrs thereafter (n = 5 per group). Control mice received physiologic saline (n = 5 per group). Analysis included in vivo fluorescence microscopy of hepatic microcirculation and hepatocellular apoptosis as well as plasma malondialdehyde concentrations as reactive oxygen species-dependent lipid peroxidation product and hepatic adenosine triphosphate levels.

MAIN RESULTS

Administration of Gal-lipopolysaccharide in uncoupling protein 2+/+ mice caused systemic cytokine release and malondialdehyde production. Further, it provoked marked hepatic damage, characterized by intrahepatic leukocyte recruitment (10.5 +/- 1.3 n/mm2 vs. 3.3 +/- 0.5 n/mm2), microvascular perfusion failure (33.1% +/- 1.6% vs. 2.3% +/- 0.4%), and adenosine triphosphate depletion (3.4 +/- 0.9 micromol/g vs. 6.4 +/- 0.9 micromol/g). Furthermore, uncoupling protein +/+ mice revealed a huge rise in cell apoptosis, given by high numbers of hepatocytes exhibiting nuclear chromatin fragmentation (44.9 +/- 11.5 n/mm2 vs. 0.0 +/- 0.0 n/mm2) and cleaved caspase-3 expression (1.24 +/- 0.24 vs. 0.06 +/- 0.04). Liver injury was coexistent with enzyme release (alanine aminotransferase 442 +/- 126 U/L vs. 57 +/- 12 U/L) and necrotic cell death. Of interest, Gal-lipopolysaccharide-exposed uncoupling protein 2-/- mice exhibited higher rates of hepatocellular apoptosis (135.6 +/- 46.0 n/mm2) as well as cleaved caspase-3 expression (1.75 +/- 0.25), however, preserved hepatic adenosine triphosphate (6.4 +/- 1.7), milder perfusion failure (24.5 +/- 2.4) and decreased leukocyte recruitment (2.7 +/- 0.2), less necrotic injury, lower transaminase levels (340 +/- 91), and finally better survival rates.

CONCLUSION

The higher adenosine triphosphate availability in uncoupling protein 2-deficient mice might allow hepatocytes to undergo apoptosis as an energy-consuming mode of cell death, while at the same time cellular adenosine triphosphate levels seem to increase hepatic resistance against harmful effects upon Gal-lipopolysaccharide exposure. As net result, uncoupling protein 2 deficiency provided protection under endotoxemic stress conditions, underlining the significant role of the bioenergetic status in critical illness.

Multiple organ dysfunction syndrome pathogenesis and care: a complex systems' theory perspective

AIMS AND OBJECTIVES

To discuss multiple organ dysfunction syndrome (MODS) from a complex systems' theory perspective and to delineate a conceptual framework for the development and care of MODS.

BACKGROUND

MODS is an intricate and devastating manifestation of critical illness characterized by widespread aberrant molecular, cellular and systemic responses.

DESIGN AND METHODS

Narrative literature review (MEDLINE, CINAHL databases) and knowledge synthesis with the theoretical assertions of chaos and complex systems' theory. Cellular and systemic response paradoxes in MODS (including cellular hypoxia, cell death and signalling) are reviewed.

RESULTS

The diseased person is depicted as a complex adaptive system. The relevancy of some of the principles of complex chaotic systems' theory to the proposed model is illustrated, including sensitive dependence on initial conditions, emergence, attractors, self-organization, self-organized criticality and emerging order. The transition from life-supporting to death-related organismic responses is illustrated as a critical event in MODS and care implications are drawn.

CONCLUSIONS

Patient responses in MODS appear to conform to the principles of chaotic systems. Death is illustrated not as a consequence of homeostatic failure but as a 'deliberate' self-organized phenomenon entailing multiple dynamically evolving mechanisms.

RELEVANCE TO CLINICAL PRACTICE

Some of the principles of chaotic complex systems may need to be taken into account to advance care in MODS. An alternative theoretical perspective may support nurses to conceptualize both MODS and their role in a way that will help them to cope better with this devastating syndrome and develop practice.

Iron behaving badly: inappropriate iron chelation as a major contributor to the aetiology of vascular and other progressive inflammatory and degenerative diseases

BACKGROUND

The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular 'reactive oxygen species' (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation.

REVIEW

We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation).The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible.This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, since in some circumstances (especially the presence of poorly liganded iron) molecules that are nominally antioxidants can actually act as pro-oxidants. The reduction of redox stress thus requires suitable levels of both antioxidants and effective iron chelators. Some polyphenolic antioxidants may serve both roles.Understanding the exact speciation and liganding of iron in all its states is thus crucial to separating its various pro- and anti-inflammatory activities. Redox stress, innate immunity and pro- (and some anti-)inflammatory cytokines are linked in particular via signalling pathways involving NF-kappaB and p38, with the oxidative roles of iron here seemingly involved upstream of the IkappaB kinase (IKK) reaction. In a number of cases it is possible to identify mechanisms by which ROSs and poorly liganded iron act synergistically and autocatalytically, leading to 'runaway' reactions that are hard to control unless one tackles multiple sites of action simultaneously. Some molecules such as statins and erythropoietin, not traditionally associated with anti-inflammatory activity, do indeed have 'pleiotropic' anti-inflammatory effects that may be of benefit here.

CONCLUSION

Overall we argue, by synthesising a widely dispersed literature, that the role of poorly liganded iron has been rather underappreciated in the past, and that in combination with peroxide and superoxide its activity underpins the behaviour of a great many physiological processes that degrade over time. Understanding these requires an integrative, systems-level approach that may lead to novel therapeutic targets.

Glycogen synthase kinase-3 negatively regulates anti-inflammatory interleukin-10 for lipopolysaccharide-induced iNOS/NO biosynthesis and RANTES production in microglial cells

The inflammatory effects of glycogen synthase kinase-3 (GSK-3) have been identified; however, the potential mechanism is still controversial. In this study, we investigated the effects of GSK-3-mediated interleukin-10 (IL-10) inhibition on lipopolysaccharide (LPS)-induced inflammation. Treatment with GSK-3 inhibitor significantly blocked LPS-induced nitric oxide (NO) production as well as inducible NO synthase (iNOS) expression in BV2 murine microglial cells and primary rat microglia-enriched cultures. Using an antibody array and enzyme-linked immunosorbent assay, we found that GSK-3-inhibitor treatment blocked LPS-induced upregulation of regulated on activation normal T-cell expressed and secreted (RANTES) and increased IL-10 expression. The time kinetics and dose-response relations were confirmed. Reverse transcription-polymerase chain reaction showed changes on the messenger RNA level as well. Inhibiting GSK-3 using short-interference RNA, and transfecting cells with dominant-negative GSK-3beta, blocked LPS-elicited NO and RANTES expression but increased IL-10 expression. In contrast, GSK-3beta overexpression upregulated NO and RANTES but downregulated IL-10 in LPS-stimulated cells. Treating cells with anti-IL-10 neutralizing antibodies to prevent GSK-3 from downregulating NO and RANTES showed that the anti-inflammatory effects are, at least in part, IL-10-dependent. The involvement of Akt, extracellular signal-regulated kinase, p38 mitogen-activated protein kinase and nuclear factor-kappaB that positively regulated IL-10 was demonstrated. Furthermore, inhibiting GSK-3 increased the nuclear translocation of transcription factors, that all important for IL-10 expression, including CCAAT/enhancer-binding protein beat (C/EBPbeta), C/EBPdelta, cAMP response binding element protein and NF-kappaB. Taken together, these findings reveal that LPS induces iNOS/NO biosynthesis and RANTES production through a mechanism involving GSK-3-mediated IL-10 downregulation.

The complement anaphylatoxin C5a induces apoptosis in adrenomedullary cells during experimental sepsis

Sepsis remains a poorly understood, enigmatic disease. One of the cascades crucially involved in its pathogenesis is the complement system. Especially the anaphylatoxin C5a has been shown to have numerous harmful effects during sepsis. We have investigated the impact of high levels of C5a on the adrenal medulla following cecal ligation and puncture (CLP)-induced sepsis in rats as well as the role of C5a on catecholamine production from pheochromocytoma-derived PC12 cells. There was significant apoptosis of adrenal medulla cells in rats 24 hrs after CLP, as assessed by the TUNEL technique. These effects could be reversed by dual-blockade of the C5a receptors, C5aR and C5L2. When rats were subjected to CLP, levels of C5a and norepinephrine were found to be antipodal as a function of time. PC12 cell production of norepinephrine and dopamine was significantly blunted following exposure to recombinant rat C5a in a time-dependent and dose-dependent manner. This impaired production could be related to C5a-induced initiation of apoptosis as defined by binding of Annexin V and Propidium Iodine to PC12 cells. Collectively, we describe a C5a-dependent induction of apoptotic events in cells of adrenal medulla in vivo and pheochromocytoma PC12 cells in vitro. These data suggest that experimental sepsis induces apoptosis of adrenomedullary cells, which are responsible for the bulk of endogenous catecholamines. Septic shock may be linked to these events. Since blockade of both C5a receptors virtually abolished adrenomedullary apoptosis in vivo, C5aR and C5L2 become promising targets with implications on future complement-blocking strategies in the clinical setting of sepsis.

The role of P38 MAPK and PKC in BLP induced TNF-alpha release, apoptosis, and NFkappaB activation in THP-1 monocyte cells

BACKGROUND

P38 mitogen activated protein kinase (p38 MAPK) is a critical mediator of the inflammatory response, which makes it a suitable candidate as a novel therapeutic strategy for inflammatory conditions. In this study, we set out to examine the precise role of both protein kinase C (PKC) and P38 MAPK signaling kinases in bacterial lipoprotein (BLP) induced nuclear factor-kappa B (NFkappaB) activation and tumor necrosis factor-alpha (TNFalpha) release in THP-1 monocytic cell line.

MATERIALS AND METHODS

THP-1 cells were incubated with BLP(0-1000 ng/mL), phorbol myristate acetate (PMA; 0-100 microg/mL) or a combination of both for 6 and 24 h, with or without pretreatment with SB202190, a specific inhibitor of p38 MAPK and bisindolylmaleimide I, a specific inhibitor of PKC (0-200 microm). Cell supernatants were analyzed for TNF-alpha release and apoptosis. NFkappaB activity was analyzed by electromobility supershift assay.

RESULTS

BLP induced TNF-alpha release was significantly reduced by pretreatment with SB202190 at all concentrations (428.7 +/- 5.9 versus 51 +/- 0.8 rhog/mL, P < 0.05). Pretreatment with bis I significantly inhibited TNF-alpha release at higher concentrations (200 microM) (429.7 +/- 5.9 versus 194.9 +/- 42.68 rhog/mL, P < 0.05) but this was much less effective than SB202190. PMA induced TNF-alpha release was not inhibited at 6 h by either SB202190 or bis I, but was significantly so at 24 h (148.5 +/- 9.8 versus 24 +/- 1.7 and 25.1 +/- 4.4 rhog/mL, P < 0.05). BLP or lipopolysaccharide (LPS) did not result in apoptosis in THP-1 cells (P > 0.05) with PMA inducing apoptosis in a time- and dose-dependent manner. In combination with BLP (1000 ng/mL) but not LPS (1000 ng/mL), low dose PMA resulted in a significant increase in apoptosis, 6% +/- 0.5% (Control) versus 9.2% +/- 0.3% (P < 0.05) and 7% +/- 2.2% (Control) versus 7.7% +/- 0.3% (P > 0.05), respectively. This synergistic effect was inhibited by bisindolylmaleimide 100 nm, 8.9% +/- 0.9% (Control) versus 9.8% +/- 0.2% (P > 0.05). PMA and BLP induced rapid nuclear translocation of NFkappaB, which was inhibited by pretreatment with both SB-202190 and bis I, and SB202190 but not bis I, respectively.

CONCLUSIONS

P38 is a critical mediator of BLP induced TNF-alpha release and NFkappaB activation, whereas PKC is only partially responsible for its response. P38 and PKC are both critical mediators of PMA induced TNF-alpha release and NFkappaB activation.

Macrophage migration inhibitory factor governs endothelial cell sensitivity to LPS-induced apoptosis

Human endothelial cells (EC) are typically resistant to the apoptotic effects of stimuli associated with lung disease. The determinants of this resistance remain incompletely understood. Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine produced by human pulmonary artery EC (HPAEC). Its expression increases in response to various death-inducing stimuli, including lipopolysaccharide (LPS). We show here that silencing MIF expression by RNA interference (MIF siRNA) dramatically reduces MIF mRNA expression and the LPS-induced increase in MIF protein levels, thereby sensitizing HPAECs to LPS-induced cell death. Addition of recombinant human MIF (rhMIF) protein prevents the death-sensitizing effect of MIF siRNA. A common mediator of apoptosis resistance in ECs is the death effector domain (DED)-containing protein, FLIP (FLICE-like inhibitory protein). We show that LPS induces a transcription-independent increase in the short isoform of FLIP (FLIP(s)). This increase is blocked by MIF siRNA but restored with the addition of recombinant MIF protein (rHMIF). While FLIP(s) siRNA also sensitizes HPAECs to LPS-induced death, the addition of rhMIF does not affect this sensitization, placing MIF upstream of FLIP(s) in preventing HPAEC death. These studies demonstrate that MIF is an endogenous pro-survival factor in HPAECs and identify a novel mechanism for its role in apoptosis resistance through the regulation of FLIP(s). These results show that MIF can protect vascular endothelial cells from inflammation-associated cell damage.

Apoptosis in Critical Illness: A Primer for the Intensivist

The complexities of the cell cycle have occupied a prominent place in the history of cellular biology. Recognition of the process of mitosis dates back over a century, when Fol, Butschli, and Strasburger identified a network of intracellular points and lines, then called the karyokinetic figure, and today known as the mitotic apparatus. This discovery, dating to 1873, laid the foundation for the discovery of chromosomes and, later, the fundamental biologic processes of mitosis and meiosis [1]. But, while cellular growth and proliferation were understood to be essential to the emergence of multicellular organisms, the corollary — that controlled cell death must be part of this calculus of cellular homeostasis — was not appreciated until quite recently. Although cell death was first described in 1859 by Virchow, it took more than a century to appreciate the importance of programmed cell death as a physiological process that eliminated unwanted cells [2]. The term ‘apoptosis’ was coined in 1972 by Kerr, Wyllie, and Currie to describe a distinct type of cell death characterized by the degradation of cellular constituents into membrane-bound apoptotic bodies [3]. Since then, recognition of the importance of apoptosis in health and disease, and an understanding of its cellular mechanisms, has increased exponentially.

Apoptosis in Critical Illness: A Primer for the Intensivist

The complexities of the cell cycle have occupied a prominent place in the history of cellular biology. Recognition of the process of mitosis dates back over a century, when Fol, Butschli, and Strasburger identified a network of intracellular points and lines, then called the karyokinetic figure, and today known as the mitotic apparatus. This discovery, dating to 1873, laid the foundation for the discovery of chromosomes and, later, the fundamental biologic processes of mitosis and meiosis [1]. But, while cellular growth and proliferation were understood to be essential to the emergence of multicellular organisms, the corollary — that controlled cell death must be part of this calculus of cellular homeostasis — was not appreciated until quite recently. Although cell death was first described in 1859 by Virchow, it took more than a century to appreciate the importance of programmed cell death as a physiological process that eliminated unwanted cells [2]. The term ‘apoptosis’ was coined in 1972 by Kerr, Wyllie, and Currie to describe a distinct type of cell death characterized by the degradation of cellular constituents into membrane-bound apoptotic bodies [3]. Since then, recognition of the importance of apoptosis in health and disease, and an understanding of its cellular mechanisms, has increased exponentially.

Local interaction of apoptotic hepatocytes and Kupffer cells in a rat model of systemic endotoxemia

AIM

There is strong evidence that hepatocellular apoptosis is not only initiated by circulating blood cells which become adherent within the endotoxemic liver, but also contributes to further sustain the inflammatory cell-cell response.

METHODS

Because previous studies assumed the importance of the role of cellular cross-talk in mediating inflammatory liver injury, we herein examined the activation of Kupffer cells (KCs) and their spatial coincidence with intrahepatic leukocyte adherence and hepatocellular apoptosis at 6 h after intraperitoneal exposure of rats with lipopolysaccharide (10 mg/kg).

RESULTS

In vivo multifluorescence microscopy revealed liver injury including nutritive perfusion failure, tissue hypoxia, leukocyte accumulation, as well as KC activation and parenchymal apoptotic cell death. Detailed spatial analysis revealed frequent colocalization of activated KCs with apoptotic hepatocytes. Colocalization was absent in saline-treated controls.Colocalization was confirmed by histochemistry, which showed ED1-positive KCs neighboring and engulfing TUNEL-positive hepatocytes. Colocalization of KCs with leukocytes ranged between 4% and 5% and did not increase in endotoxemic animals. Taken together, the present results indicate that apoptotic cell death of hepatocytes may stimulate phagocytosis by neighboring KCs. Direct KC-leukocyte contact seems not to be mandatory for cellular communication in the process of hepatocellular apoptosis.

CONCLUSION

With respect to the fundamental importance of cell apoptosis, improved knowledge of these cell-cell interactions might allow the development of new therapeutic strategies through the regulation of apoptotic cell death.

Emerging therapies for treatment of acute lung injury and acute respiratory distress syndrome

Acute lung injury/acute respiratory distress syndrome (ALI/ARDS) is a life-threatening form of respiratory failure that affects a heterogeneous population of critically ill patients. Although overall mortality appears to be decreasing in recent years due to improvements in supportive care, there are presently no proven, effective pharmacological therapies to treat ARDS and prevent its associated complications. The most common cause of death in ARDS is not hypoxemia or pulmonary failure, but rather multiple organ dysfunction syndrome (MODS), suggesting that improving survival in patients with ARDS may be linked to decreasing the incidence or severity of MODS. The key to developing novel treatments depends, in part, on identifying and understanding the mechanisms by which ARDS leads to MODS, although the heterogeneity and complexity of this disorder certainly poses a challenge to investigators. Novel therapies in development for treatment of ALI/ARDS include exogenous surfactant, therapies aimed at modulating neutrophil activity, such as prostaglandin and complement inhibitors, and treatments targeting earlier resolution of ARDS, such as beta-agonists and granulocyte macrophage colony-stimulating factor. From a clinical perspective, identifying subpopulations of patients most likely to benefit from a particular therapy and recognising the appropriate stage of illness in which to initiate treatment could potentially lead to better outcomes in the short term.

Recombinant activated protein C induces dose-dependent changes in inflammatory mediators, tissue damage, and apoptosis in in vivo rat model of sepsis

BACKGROUND

Sepsis is the tenth leading cause of death in the U.S. and creates a $16.7 billion burden on the healthcare system every year. Sepsis is characterized by a severe uncontrolled inflammatory response to the infection. Various cells and mediators are activated, and the result is a complex interaction between the inflammation and coagulation cascades leading to capillary leakage and end-organ ischemia. Current therapeutic strategies, such as recombinant human activated protein C, focus on this interplay. However, this drug's precise mechanism of action is not well understood. The aim of this study was to assess cytokine production, tissue damage, and apoptosis in a rat model of sepsis in response to various doses of this drug.

METHODS

Sprague-Dawley rats were divided into eight groups, including negative control, sham, sepsis only, and five treatment groups. The sepsis and treatment groups were given Escherichia coli. Each of the treatment groups received a different dose of recombinant activated protein C to complete 30-min or 270-min infusion times from the onset of sepsis. Serum and tissue samples were collected. Interleukin (IL)-6 concentrations were measured, and serum malondialdehyde (MDA) concentrations were determined to assess generalized tissue damage. Apoptosis in the lung was evaluated using a semi-quantitative ligation-mediated polymerase chain reaction assay.

RESULTS

The physiologic effects of recombinant activated protein C are dose dependent and determined by the duration of infusion. Higher doses of the drug were associated with less inflammation, apoptosis, and generalized tissue damage. Sepsis increased the mean concentration of MDA (2.1 vs. 10.9 pmol/mg of protein) and IL-6 (0 vs. 10,763 pg/mL) compared with sham-treated animals, as well as the magnitude of apoptosis in lung (2,037 vs. 8,709 pixels) (all p < 0.05). Infusion of recombinant activated protein C attenuated these responses in a dose-response manner. Interleukin-6 and MDA concentrations were increased by lower-dose therapy, but attenuated significantly by the higher-dose infusion at 5 mg/kg/h. Apoptosis was attenuated by both the lower and the higher dose, but more so with the higher dose.

CONCLUSIONS

These data can assist in establishing an optimal dose and infusion time of this drug for extrapolation to therapy of human beings. The goal now is to elucidate these findings further so that the maximum benefit of the drug may be achieved with the least possible harmful effects.

Microcirculatory function monitoring at the bedside--a view from the intensive care

Microcirculatory dysfunction plays a key role in the pathophysiology of various disease states and may consequently impact patient outcome. Until recently, the evaluation of the microcirculation using different measurement techniques has been mostly limited to animal and human research. With technical advances, microcirculatory monitoring nowadays becomes more and more available for application in clinical praxis. Unfortunately, measurements within the microcirculation are mostly limited to easily accessible surfaces, such as skin, muscle and tongue. Due to major differences in the physiologic regulation of microcirculatory blood flow and in metabolism between organs and even within different tissues in one organ, the clinical importance of regional microcirculatory measurements remains to be determined. In addition, technical methods available demonstrate large differences in the measured parameters and sampling volume, making interpretation of data even more difficult. Nonetheless, the monitoring of the microcirculation may, ahead of time, alert physicians that tissue oxygen supply becomes compromised and it may lead to a better understanding of basic pathophysiological aspects of disease. In the present review, we describe available non-invasive microcirculatory measurement techniques which can be applied clinically at the bedside. After a short discussion of physiologic and pathophysiologic basics related to microcirculatory monitoring, the measuring principles, applications, strengths and limitations of different monitoring systems are discussed.