Inhibition of exercise-induced bronchospasm by zileuton: a 5-lipoxygenase inhibitor

Recent evidence suggests that leukotrienes may have a causative role in exercise-induced asthma. Twenty-four subjects with exercise-induced asthma received either 600 mg zileuton, a 5-lipoxygenase inhibitor, or a placebo four times daily for 2 d prior to exercise challenge (a total of nine doses). The last dose was administered in the laboratory 2 h before the exercise challenge. There was no bronchodilation after nine doses of the 5-lipoxygenase inhibitor (p=0.95). The administration of zileuton inhibited bronchospasm after exercise challenge by 40.75% as compared with placebo. Five minutes after the completion of exercise, the zileuton group's FEV1 was 85.76% of the preexercise value, compared with 73.92% of the preexercise value in the placebo group (p<0.01). The maximum percent change in baseline FEV1 after zileuton was a 15.58% decrement from the preexercise level, as compared with a 28.1% decrease after placebo (p<0.001). Five minutes after exercise, the FVC after zileuton was 92.76% of the preexercise value, as compared with 86.26% after placebo (p<0.05). This is the first study in which a 5-lipoxygenase inhibitor has been shown to attenuate exercise-induced asthma. These results suggest that leukotrienes are important biochemical mediators in the development of exercise-induced bronchospasm, and that leukotriene inhibit may have a role in the treatment of this disorder.

Acute inflammatory response in the mouse: exacerbation by immunoneutralization of lipocortin 1

1. An immuno-neutralization strategy was employed to investigate the role of endogenous lipocortin 1 (LC1) in acute inflammation in the mouse. 2. Mice were treated subcutaneously with phosphate-buffered solution (PBS), non-immune sheep serum (NSS) or with one of two sheep antisera raised against LC1 (LCS3), or its N-terminal peptide (LCPS1), three times over a period of seven days. Twenty four hours after the last injection several parameters of acute inflammation were measured including zymosan-induced inflammation in 6-day-old air-pouches, zymosan-activated serum (ZAS)-induced oedema in the skin, platelet-activating factor (PAF)-induced neutrophilia and interleukin-1 beta (IL-1 beta)-induced corticosterone (CCS) release. 3. At the 4 h time-point of the zymosan inflamed air-pouch model, treatment with LCS3 did not modify the number of polymorphonuclear leucocytes (PMN) recruited: 7.84 +/- 1.01 and 7.00 +/- 0.77 x 10(6) PMN per mouse for NSS- and LCS3 group, n = 7. However, several other parameters of cell activation including myeloperoxidase (MPO) and elastase activities were increased (2.2 fold, P < 0.05, and 6.5 fold, P < 0.05, respectively) in the lavage fluids of these mice. Similarly, a significant increase in the amount of immunoreactive prostaglandin E2 (PGE2; 1.81 fold, P < 0.05) and IL-1 alpha (2.75 fold, P < 0.05), but not tumour necrosis factor-alpha (TNF-alpha), was also observed in LCS3-treated mice. 4. The recruitment of PMN into the zymosan inflamed air-pouches by 24 h had declined substantially (4.13 +/- 0.61 x 10(6) PMN per mouse, n = 12) in the NSS-treated mice, whereas high values were still measured in those treated with LCS3 (9.35 +/- 1.20 x 10(6) PMN per mouse, n = 12, P < 0.05). A similar effect was also found following sub-chronic treatment of mice with LCPS1: 6.48 +/- 0.10 x 10(6) PMN per mouse, vs. 2.77 +/- 1.20 and 2.64 +/- 0.49 x 10(6) PMN per mouse for PBS- and NSS-treated groups (n = 7, P < 0.05). Most markers of inflammation were also increased in the lavage fluids of LCS3-treated mice: MPO and elastase showed a 2.47 fold and 17 fold increase, respectively (P < 0.05 in both cases); TNF-alpha showed a 11.1 fold increase (P < 0.05) whereas the IL-1 alpha levels were not significantly modified. PGE2 was still detectable in most (5 out of 7) of the mice treated with LCS3 but only in 2 out of 7 of the NSS-treated mice. 5. Intradermal injection of 50% ZAS caused a significant increase in the 2 hoedema formation in the skin of LCS3-treated mice in comparison to PBS- and NSS-treated animals: 16.7 +/- 1.5 microliters vs. 10.8 +/- 1.2 microliters and 10.2 +/- 1.0 microliters, respectively (n = 14 mice per group, P < 0.05). ZAS-induced oedema had subsided by 24 h in control animals but a residual significant amount of extravasation was still detectable in LCS3-treated mice: 4.4 +/- 0.8 microliters (P < 0.05). 6. A recently described model driven by endogenous glucocorticoids is the blood neutrophilia observed following administration of PAF. In our experimental conditions, a single bolus of PAF (100 ng, i.v.) provoked a marked neutrophilia at 2 h (2.43 and 2.01 fold) in NSS- and PBS-treated mice (n = 11), respectively, which was significantly attenuated in the animals treated with LCS3: 1.26 fold increase in circulating PMN (n = 11, P < 0.01 vs. NSS- and PBS-groups). 7. Intraperitoneal injection of IL-1 beta (5 micrograms kg-1) caused a marked increase in circulating plasma CCS by 2 h, to a similar extent in all experimental groups. In contrast, measurement of CCS levels in the plasma of mice bearing air-pouches inflamed with zymosan revealed significant differences between LCS3 and NSS-treated mice at the 4 h time-point: 198 +/- 26 ng ml-1 vs. 110 +/- 31 ng ml-1 (n = 8, P < 0.05). 8. In conclusion, we found a remarkable exacerbation of the inflammatory process with respect to both humoral and cellular components in mice passively immunised agains

The impact of new technologies to diagnose and treat periodontal disease. A look to the future

The last 25 years have brought unprecedented advances to our understanding of periodontal disease. Consider that in 1970 periodontitis was believed to effect most individuals over the age of 35 years, to progress steadily in an individual once initiated until teeth were lost, to be the primary cause of tooth loss in adults, to be caused by the bacterial mass accumulating on the tooth surface and subgingivally, and to involve the host in some fashion or another. In the 25 years since then, impressive research advances in the epidemiology of periodontal disease, the specific bacterial etiology of periodontal disease and the immunoinflammatory mediators of periodontal tissue destruction have greatly altered our view of periodontal disease. Thus, given these research advances in the understanding of periodontitis, what may the future hold for improved diagnosis and treatment of periodontal disease? Impressive research into new ways to diagnose the periodontal diseases is well underway. Investigators are seeking new ways to diagnose an individual's degree of risk for periodontal disease initiation, susceptibility to disease progression, level of disease "activity" and the likely response to treatment and recurrence of active disease. New diagnostic tests should greatly advance our ability to more accurately and specifically diagnose periodontal disease. The future also looks promising for new treatment strategies to slow or arrest periodontal disease progression. The bacterial specificity of periodontal disease etiology revealed since 1970 has logically led to the use of antibiotics in periodontitis treatment. In the late 1980s the concept of locally delivering antibiotics to the periodontal pocket was introduced, and subsequent clinical trials have indicated that it is possible to reduce pocket depth and inflammation with tetracycline locally delivered to the periodontal pocket. Likely, we have barely scratched the surface in studying the efficacy of locally delivery antimicrobial agents to alter the progression of periodontal disease. As new agents are developed and better delivery systems to the periodontal pocket are developed, the future should see a variety of antimicrobial agents available which can slow periodontal disease progression. The future also holds promise for slowing periodontal disease progression by blocking inflammatory pathways important in periodontal tissue destruction. Clinical trials of flubiprofen, naproxen and ketoprofen indicate that it is possible to slow periodontal disease progression with non-steroidal anti-inflammatory drugs which inhibit one destructive pathway. In addition, data from animal models indicate that chemically modified tetracycline as an inhibitor of collagenase can slow disease progression in animals. Again, we have likely only just begun to explore the wide range of molecular mediators of tissue destruction which may be targeted for blocking and thereby slow or arrest periodontal disease progression. Last, research into regenerating periodontal structures lost as a result of disease has had a noteworthy record of progress in the past 25 years. Techniques that utilize bone grafts, root treatments, tissue guiding membranes or polypeptide growth factors have ably indicated that it is possible to regenerate new attachment structures in humans. As investigators continue to unravel the mysteries of the embryonic development of the periodontium, the ability to predictably regenerate lost periodontal attachment structures holds great promise for the future.

Alterations in calcium signaling and cellular responses in septic injury

The immune and endocrine mediators that are released during sepsis (e.g., tumor necrosis factor [TNF] alpha, interleukin [IL]-1, IL-6, transforming growth factor [TGF] beta, prostaglandin [PG] E2, catecholamines, vasopressin, glucagon, insulin, and glucocorticoids) can produce inappropriate detrimental cellular responses contributing to exacerbation of septic injury. Examples of such sepsis-related inappropriate responses are: exaggerated hepatic acute-phase protein (APP) expression and release skeletal muscle insulin resistance, and suppressed T-lymphocyte proliferation. The studies discussed in this article present evidence that the generation of the sepsis-related hepatic, skeletal muscle, and T-lymphocyte responses emanate from alterations in intracellular Ca2+ (Ca2+i) homeostasis. In hepatocytes, there is indication of a sepsis-mediated increase in Ca2+ influx from the extracellular milieu leading to a sustained increase in the apparent resting cell Ca2+i concentration ([Ca2+]i) and its depressed elevation on stimulation with Ca2+-mobilizing hormones such as catecholamines and vasopressin. These Ca(2+)- related changes can affect not only the signaling pathways in which Ca2+i itself serves as a signaling component, but also the signaling systems turned on by other sepsis-induced agonists which may not be dependent on Ca2+ signaling. TGF-beta, IL-1, TNF alpha, and IL-6 activate a primarily protein kinase C (PKC)-dependent intracellular signal system for the elicitation of a normal hepatic APP response (APPR). The increased apparent basal [Ca2+]i in sepsis can hypersensitize PKC activation and thus lead to an exaggerated APPR. In the skeletal muscle, an evident increase in Ca2+ membrane flux during sepsis pointed to an increase in the basal [Ca2+]i resulting from a plausible cytokine-mediated overactivation of the voltage-sensitive Ca2+ channels. The increased basal [Ca2+]i can negatively modulate the insulin-mediated stimulation of GLUT4-dependent glucose transport despite the possibility that Ca2+i might not participate as a component in the insulin-receptor-regulated signaling pathway. Increased [Ca2+]i in skeletal myocytes can either directly promote the phosphorylation of GLUT4 or prevent its dephosphorylation, both of which effectively block insulin stimulation of glucose uptake, thereby contributing to insulin resistance. In T lymphocytes, septic injury appears to induce an attenuation in the mitogen and, thus, presumably a T-cell antigen receptor (TCR)-mediated elevation in [Ca2+]i without affecting the basal [Ca2+]i. This decrease in TCR-related Ca2+i mobilization evidently contributes to the suppression of T lymphocyte proliferation during sepsis, probably via an in vivo action of prostaglandin (PG) E2 on the T cells during sepsis. The blockade of PGE2 production after indomethacin administration to septic animals prevents alterations in both T-cell Ca2+i mobilization and proliferation. PGE2 probably acts through its second messenger, cyclic adenosine 3'5'-monophosphate, which can antagonize Ca2+i signaling in T cells.

Calcium: a regulator of the inflammatory response in endotoxemia and sepsis

Calcium functions as a critical intracellular second messenger and regulates many cellular processes such as muscle contractility, glycogen and protein turnover, hormone secretion, and vascular smooth muscle tone which are markedly abnormal during sepsis/endotoxemia. There also is increasing recognition of the role of calcium in the production of a variety of cytokines such as tumor necrosis factor alpha and interleukin-1 beta, which are important mediators of sepsis. Our hypothesis is that disturbances in cellular calcium regulation are responsible for or contribute to many of the metabolic manifestations of sepsis/endotoxemia and may be the driving force behind the development of multiorgan failure. In this article, we focus on a) new insights into calcium's regulation of the inflammatory cascade, b) the controversy concerning whether free cytosolic calcium concentration ([Ca2+]i) is increased in the disorder, and c) the potential therapeutic uses of calcium antagonists. An important message is that there are fundamental differences in the pathophysiology of the endotoxin model versus the cecal ligation and perforation (CLP) model of sepsis. Although calcium antagonists improve survival in the endotoxin model, they increase mortality in the CLP model of sepsis. Possible reasons for the differences in the effect of the drugs in the two different models and insight into the mechanisms of cell injury in endotoxin versus sepsis are presented.

Regulation of endothelial permeability by second messengers

The mechanisms by which mediators such as oxidants released by neutrophil (PMN) activation increase endothelial permeability are poorly understood. The focus of this article is to identify some of these mechanisms. Studies using endothelial cell monolayers in culture have shown that PMN activation increases endothelial permeability both in the presence and absence of PMN-endothelial monolayer contact. Hydrogen peroxide (H2O2), an oxidant released by PMN activation, plays an important role in PMN-induced increases in endothelial permeability. The results of these studies suggest that, as with other mediators of inflammation (e.g., histamine, thrombin) the mechanism of H2O2-induced increase in endothelial permeability involves activation of endothelial protein kinase C (PKC) and increase in endothelial cytosolic Ca2+.

Inflammatory mechanisms in Alzheimer's disease

In recent years many studies have indicated an involvement of inflammatory mechanisms in Alzheimer's disease (AD). Acute-phase proteins such as alpha 1-antichymotrypsin and c-reactive protein, elements of the complement system, and activated microglial and astroglial cells are consistently found in brains of AD patients. Most importantly, also cytokines such as interleukin-6 (IL-6) have been detected in the cortices of AD patients, indicating a local activation of components of the unspecific inflammatory system. Up to now it has remained unclear whether inflammatory mechanisms represent a primary event or only an unspecific reaction to brain tissue damage. Therefore, we investigated whether IL-6 immunoreactivity could be found in plaques prior to the onset of neuritic changes, or whether the presence of this cytokine is restricted to later stages of plaque pathology. We confirmed our previous observation that IL-6 is detectable in a significant proportion of plaques in the brains of demented patients. In AD patients IL-6 was found in diffuse plaques in a significant higher ratio as would have been expected from a random distribution of IL-6 among all plaque types. This observation suggests that IL-6 may precede neuritic changes, and that immunological mechanism may be involved both in the transformation from diffuse to neuritic plaques in AD and in the development of dementia.

Inflammation of the brain after ischemia

Cytokines which promote emigration of leukocytes from the vascular lumen into the injured brain tissue are produced at the site of incipient cerebral infarction. The blood-borne invaders then accelerate the decomposition of brain cells by their toxic by-products, phagocytic action, and by the immune reaction. Recently accumulated data in our laboratories and other research facilities show that depleting the amount of circulating leukocytes or administering anti-inflammatory chemicals such as cytokine blocking agents, anti-adhesion molecule antibodies, and immunosuppressants effectively minimize the size of ischemia induced cerebral infarction. Based on the fact the leukocyte invasion of the affected brain tissue occurs 6 to 24 hours after onset of ischemia, administration of an anti-inflammatory therapy may widen the therapeutic window against stroke.

Current treatment of severely burned patients

OBJECTIVE

The authors provide an update on a multidisciplinary approach to the treatment of severely burned patients. A review of studies and clinical trials from the past to the present include fluid resuscitation, sepsis, immune function, hypermetabolism, early excision, wound healing, scar formation, and inhalation injury.

SUMMARY BACKGROUND DATA

Advances in treating initial burn shock, infection control, early wound closure, and modulation of the hypermetabolic response have decreased morbidity and mortality in the last two decades. Specialized burn care centers, using a multidisciplinary approach, not only successfully treat large burns and their complications, but provide the necessary rehabilitation and psychological support required for readjustment back into society.

CONCLUSIONS

Thermal injury results in a number of physiologic alterations that can be minimized by adequate fluid resuscitation to maintain tissue perfusion, early excision of burn wounds, and rapid wound coverage. These measures, in combination with antibiotic coverage and nutritional support in the form of early enteral tube feedings, will decrease the hypermetabolic response and the incidence of sepsis that can lead to hemodynamic instability and organ failure. Ongoing clinical trials using anabolic agents (e.g., recombinant human growth hormone) and pharmacologic agents that modulate inflammatory and endocrine mediators (e.g., ibuprofen and propranolol) show promise in the treatment of severe burn injuries.

Mediators of inflammation in chronic inflammatory bowel disease

A distinguishing feature of inflammatory bowel disease (IBD) is its apparently spontaneous, chronic relapsing course. Despite extensive research over several decades the etiology of IBD remains unknown, but evidence has accumulated to suggest that the mucosal inflammatory response may be caused by (i) a defective mucosal barrier function resulting in an abnormally increased exposure to luminal antigens and toxins, (ii) an appropriate immunologic response to an unusual infection, antigen or toxin, or (iii) an inappropriate immunological response to ubiquitous antigens or stimuli. In recent years, the identification of established and potential mediators of inflammation has expanded to include eicosanoids, platelet activating factor, biogenic amines, kinins, complement-derived peptides, chemotactic peptides, cytokines, neuropeptides, and reactive metabolites of oxygen and nitrogen. Thus, the study of the inflammatory process has become ever more complex. Until the predisposing and trigger factors have been identified the achievement of a more rational and effective approach to therapy in IBD relies on interruption of the mechanisms responsible for excess mediator formation. As summarized in this review on the role of soluble mediators of inflammation, several Danish gastroenterologists have been profoundly engaged in basic and clinical research in the past 25 years to place some pieces of the confusing puzzle of IBD.

[Is albumin administration useful in critical care for burnt patients?]

The most typical reaction of the organism after a major burn consists in transcapillary shift from plasma into interstitial space. Capillary hyperpermeability, but also changes in colloid osmotic gradient and decrease in interstitial hydrostatic pressure, explain the fluid shift to burned and, at minor importance, non burned areas during the first post-burn day. The extent of capillary hyperpermeability results in inefficiency of colloid infusions in reducing fluid shift to burned areas. Some groups advocate colloid supply from the eighth post-burn hour, on when hyperpermeability decreases, in non burned sites. However, for most groups, restoration of a functional interstitial space has priority during the 24 first post-burn hours, justifying crystalloid supply without colloids. Furthermore, colloid infusion could be responsible for delayed pulmonary oedema, in the first days following initial fluid replacement. After 24 post-burn hours, in patients experiencing severe albumin depletion, infusion of human albumin is justified, in order to favour oedema resorption.

Role of inflammatory mediators and adhesion molecules in the pathogenesis of aseptic loosening in total hip arthroplasties

Concentrations of prostaglandin E2, interleukin-6, and interleukin-8 were determined in the hip joint synovial fluid of 20 patients undergoing primary (n = 12) and revision (n = 8) total hip arthroplasties. Levels of soluble adhesion molecules were also investigated in these patients. There was a significant and marked increase in levels of prostaglandin E2 (P < .001), interleukin-6 (P < .011), interleukin-8 (P < .0002), soluble intercellular adhesion molecule 1 (P < .07), soluble vascular adhesion molecule 1 (P < .0006), and soluble endothelial leukocyte adhesion molecule 1 (P < .0003) in joint fluid of patients undergoing revision. On the basis of these observations, it is suggested that synovial fluid and its inflammatory contents could play a significant role in the pathogenesis of aseptic loosening in total hip arthroplasties.

Aggregatory characteristics and expression of the collagen adhesion receptor in fetal porcine platelets

Fetal wound healing differs significantly from that of the adult by its rapidity, the paucity of an inflammatory response, and the lack of scarring. In the adult, activation and aggregation of platelets at the site of injury result in the release of cytokines and inflammatory mediators that stimulate wound healing by initiating an acute inflammatory response. The aim of this study was to characterize the activity of midtrimester (day 60) and third-trimester (day 95) fetal porcine platelets (full term, 114 days) compared with that of adults in an attempt to understand the lack of inflammation in fetal wounds. The aggregatory capabilities of adult and fetal platelets were analyzed after exposure to adenosine diphosphate (ADP) concentrations of 10 mumol/L and 40 mumol/L concentrations, collagen of 0.19 mg/mL, and arachidonic acid of 0.5 mg/mL. Expression of the alpha 2 subunit of the collagen receptor (alpha 2 beta 1) was evaluated by Western blot analysis. The aggregation of day-60 fetal platelets when exposed to ADP (10 mumol/L and 40mumol/L) and collagen was significantly lower than that of the adult. The aggregation of third-trimester platelets to 10 mumol/L of ADP was similar to that of the adult and significantly greater than that of midtrimester fetuses at higher concentrations (40 mumol/L). Both fetal groups responded suboptimally to collagen, and the response was significantly less than that of adults. In contrast, arachidonic acid caused rapid and complete aggregation of both fetal platelet groups, suggesting that both mid- and late-trimester fetal platelets possessed the ability to fully aggregate with the appropriate stimulus. The different aggregatory responses to collagen could not be explained by differences in collagen receptor expression, because these were found to be similar in adults and midtrimester fetuses. It is concluded that although fetal platelets have the potential to aggregate effectively, they aggregate poorly to collagen and exhibit improved aggregation to ADP with increasing maturity. There is a transition to "adultlike" platelet aggregatory activity in the third trimester, which correlates with the period of transition to adultlike wound healing in utero. Similar expression of the alpha 2 beta 1 collagen receptor in the fetus and adult cannot explain the differences observed in their responses to collagen.

Biochemical mediators of meningeal inflammatory response to group B streptococcus in the newborn piglet model

The meningeal inflammatory response to a heat-killed mutant unencapsulated strain of type III group B Streptococcus (GBS) was studied in a newborn piglet model. GBS (10(9) colony-forming unit equivalents) or saline (control) was inoculated intraventricularly. Serial cerebrospinal fluid measurements were done at baseline and over the course of the next 24 h for cytochemical changes and production of tumor necrosis factor (TNF) and prostaglandins. In separate experiments, we defined the time course of early changes during the first 6 h and dose response relationship over a range of inocula 10(6) to 10(9) colony-forming unit equivalents. The intraventricular inoculation of the heat-killed unencapsulated GBS induced marked leukocytosis and increased protein by 6 h. These changes were preceded by a several hundredfold increase in TNF (maximum at 2 h) and prostaglandins (maximum at 2-4 h). The early and sharp rise in TNF suggests its pivotal role in initiating the inflammatory cascade. The magnitude of the inflammatory response increased with increasing bacterial dose over the range studied. To study the effect of encapsulation of GBS in the induction of meningeal inflammation, we compared the response to the unencapsulated mutant strain with that to the encapsulated parent strain. The encapsulated strain produced much smaller inflammatory changes, and only with high doses of bacteria. The GBS cell wall appeared to be the primary bacterial product triggering inflammation. Intraventricular injection of the heat-killed unencapsulated GBS with exposed cell wall can serve as a valid model for studying neonatal meningitis.

Synthesis of proinflammatory cytokines by human gingival fibroblasts in response to lipopolysaccharides and interleukin-1 beta

We have examined the ability of gingival fibroblasts (GF) to participate in inflammatory response and function as accessory immune cells. The accessory immune function of GF cells was evaluated by their ability to elaborate proinflammatory cytokines following stimulation with lipopolysaccharides and interleukin-1 beta (IL-1 beta). Using three separate clonally derived and characterized human gingival fibroblast (GF) cell lines, we demonstrate that LPS from Actinobacillus actinomycetemcomitans (Aa) and Escherichia coli (Ec) induce mRNA and synthesis of proinflammatory cytokines, IL-1 beta, IL-6 and IL-8. IL-1 beta activation of GF cells showed that IL-1 beta non only induces the expression of IL-6, IL-8 and TNF-alpha, but also acts in an autocrine manner of GF cells and induces IL-1 beta expression. Furthermore, the continuous presence of IL-1 beta in GF cell cultures did not down regulate the response of GF cells to IL-1 beta. Pretreatment of GF cells with IL-1 beta resulted in the enhanced synthesis of TNF-alpha in response to additional IL-1 beta. These findings indicate that GF cells, in addition to providing structural support, may also function as accessory immune cells and play an important role in the initial inflammatory reaction as well as in the amplification of immune response.

The inflammatory response to cardiopulmonary bypass and its impact on postoperative myocardial function

Cardiopulmonary bypass triggers a generalized inflammatory response that is largely mediated by activation of polymorphonuclear neutrophils, their adhesion to endothelial cells, and the subsequent release of cytotoxic products. It has been known for several years that the inflammatory response to extracorporeal circulation underlies the occasional development of postoperative organ--in particular, lung--dysfunction. It is now increasingly recognized that this response can adversely affect myocardial function as well. These harmful effects are exerted by a wide spectrum of compounds, regardless of whether they act as triggers (complement-derived anaphylatoxins), mediators (cytokines, adhesion molecules), or effectors (proteolytic enzymes, oxygen free radicals, leukotrienes) of the inflammatory cascade. These considerations suggest that future strategies of myocardial protection must not be limited to interventions targeted at the heart itself but should also encompass those designed to blunt the inflammatory response to cardiopulmonary bypass.

Hemorrhagic shock

A great deal has been learned about the pathophysiologic condition of hemorrhagic shock. The response of the hormonal and inflammatory mediator systems in patients in hemorrhagic shock appears to represent a distinct set of responses different from those of other forms of shock. The classic neuroendocrine response to hemorrhage attempts to maintain perfusion to the heart and brain, often at the expense of other organ systems. This intense vasoconstriction occurs via central mechanisms. The response of the peripheral microcirculation is driven by local tissue hypoperfusion that results in vasodilation in the ischemic tissue bed. Activation of the systemic inflammatory response by hemorrhage and tissue injury is an important component of the pathophysiologic condition of hemorrhagic shock. Activators of this systemic inflammatory response include ischemia/reperfusion injury and neutrophil activation. Capillary "no-flow" with prolonged ischemia and "no-reflow" with reperfusion may initiate neutrophil activation in patients in hemorrhagic shock. The mechanisms that lead to decompensated and irreversible hemorrhagic shock include (1) "arteriolar hyposensitivity" as manifested by progressive arteriolar vasodilation and decreased responsiveness of the microcirculation to alpha-agonists, and (2) cellular injury and activation of both proinflammatory and counterinflammatory mechanisms. These changes represent a failure of the microcirculation. Redistribution of cardiac output and persistent gut ischemia after adequate resuscitation may also contribute to the development of irreversible hemorrhagic shock. Treatment of hemorrhagic shock includes rapid operative resuscitation to limit activation of the mediator systems and abort the microcirculatory changes that result from hemorrhagic shock. Volume resuscitation and control of hemorrhage, should occur simultaneously. The end point in volume resuscitation of hemorrhagic shock must be maintenance of organ system and cellular function. Whether we use adequate urine output, correction of lactic acidemia, optimization of oxygen delivery, or oxygen consumption as our specific goal, the general objective is to provide adequate crystalloid solution and packed red blood cells to achieve and maintain normal organ and cellular perfusion and function.

Role of leukotrienes in coronary artery surgery

In recent years there has been a heightened awareness of the importance of inflammatory processes in both coronary artery disease and cardiopulmonary bypass. Leukotrienes are a group of proinflammatory metabolites of arachidonic acid whose biologic effects have led to the postulation that they have a role in a broad number of functions and inflammatory disease processes. There is evidence to suggest a putative role of leukotrienes in coronary artery disease. In particular, the cysteinyl leukotrienes are potent vasoconstrictors of coronary arteries and can be generated by cell types known to be found in atherosclerotic arteries and that can participate in the process of atherosclerosis. In addition, leukotrienes are elevated in patients with cardiac ischemia, and following coronary artery bypass graft surgery, suggesting that the leukotrienes as well as other inflammatory mediators participate in the pathogenesis of cardiac ischemic syndromes. Understanding of the role of mediators involved in coronary heart disease and cardiopulmonary bypass could be of great value in managing these patients as well as developing new strategies for treatment.

Nitric oxide and interleukin-8 as inflammatory components of cystic fibrosis

We examined the production of reactive nitrogen intermediates in the tracheo-bronchial tree of patients with cystic fibrosis (CF). Examination of the soluble phase of sputa from 17 CF patients revealed the presence of high levels of NO2-/NO3- assayed by the Greiss reaction. We also examined the presence of the chemotactic cytokine interleukin-8 (IL-8) in these samples so as to assess another important inflammatory marker; high levels of IL-8 were present in the sputa of cystic fibrosis subjects. The elevated nitrite was not produced by the presence of Pseudomonas bacteria in the sputa, inasmuch as bacteria in culture released undetectable amounts of nitrite in culture media. Neutrophils from the sputa of CF patients with disease exacerbation released higher amounts of nitrite and IL-8. Neutrophils from the sputa were also shown to spontaneously release substantial amounts of nitrite in the supernatants, and this release was partly blocked by the antagonist NG-mono-methyl-L-arginine (L-NMMA). Blood neutrophils were shown to release nitrite only in response to challenge with CF-associated strains of Pseudomonas, and not exposure to cytokines. There was no significant differences in nitrite release between normal and CF blood polymorphonuclear leucocytes (PMNs). A study of upper airway epithelial cell lines showed that these cells released low amounts of nitrite after infection with CF-associated strains of Pseudomonas but not after cytokine exposure. Epithelial cell lines with CF or normal phenotypes were shown to release similar quantities of nitrite, upon stimulation with Pseudomonas. These data demonstrate that elevated levels of reactive nitrogen intermediates and IL-8 are produced in the tracheo-bronchial tree of subjects with CF. Levels of IL-8 and nitrite were higher in the secretions of CF subjects with disease exacerbation. The involvement of nitric oxide and other reactive nitrogen intermediates produced by neutrophils and other cells in the tissue damaging processes in CF deserves further investigation.

Comparative analysis of transcription and protein release of the inflammatory cytokines interleukin-1 beta (IL-1 beta) and interleukin-8 (IL-8) following major burn and mechanical trauma

The precondition for the systematic modulation of host impairing behavior of hyperactivated monocytes following trauma is to fully understand the mechanistic basis of cellular dysfunction. It was the objective of this study to scrutinize the synthesis patterns and the level of regulation of the functionally related inflammatory cytokines interleukin (IL)-1 beta and IL-8 under stressful conditions. We compared the quantity of cytokine protein release in lipopolysaccharide-stimulated in vitro cultures of peripheral blood mononuclear leukocytes with the signal intensity of the corresponding detectable mRNAs. Fourteen patients with major burn or multiple trauma on consecutive days post-trauma and healthy volunteers were studied. We saw an almost identical pattern of synthesis for both monokines during the time of observation, with a considerable impairment until day 5 post-trauma and recovery thereafter. In contrast to IL-1 beta, a clear concurrence between mRNA signal intensity and the quantity of protein release was found in the majority of patients for IL-8. From these data we conclude that the launching mechanisms for the de novo synthesis for both monokines under stress differ greatly, with IL-8 being clearly regulated on the transcriptional level, whereas the downregulation of IL-1 beta occurs, most likely, on the post-transcriptional level.

Wound healing: the role of the macrophage and other immune cells

The tissue macrophage has been shown to play a critical role in the wound healing process. Through the generation of bioactive substances, macrophages orchestrate the complex processes of cellular proliferation and functional tissue regeneration within wounds. Recent investigations have enumerated many of the specific proteins that are produced by wound macrophages at the site of injury. These include the following: 1) chemoattractants that recruit and activate additional macrophages at the site of injury, 2) growth factors that promote cellular proliferation and protein synthesis, 3) proteases and extra-cellular matrix molecules, and 4) factors that may restrain tissue growth once repair is completed. The development of therapeutic strategies to modulate wound repair continues to utilize key macrophage secretory products.

Attenuation of hepatic neutrophil sequestration by anti-CINC antibody in endotoxic rats

Cytokine-induced neutrophil chemoattractant (CINC) is a member of the chemokine alpha sub-family. It is induced in rats by tumor necrosis factor-alpha (TNF-alpha), interleukin-1, and lipopolysaccharide and is implicated in neutrophil infiltration in response to inflammatory stimuli. We tested the hypothesis that pretreatment with anti-CINC antibody or by cobra venom factor attenuates hepatic neutrophil accumulation induced by a 90 min infusion of Escherichia coli endotoxin. Changes in the expression of CD11b/c and CD18 and in plasma TNF-alpha levels were also investigated. Cultured hepatocytes and Kupffer cells of endotoxic rats produced significantly more CINC than those of saline-infused controls. CINC generation by Kupffer cells was much lower than generation by hepatocytes. Pretreatment with anti-CINC antibody or cobra venom factor significantly reduced hepatic neutrophil sequestration, but did not affect the up-regulation of CD11b/c and CD18 expression on liver-sequestered neutrophils or plasma TNF-alpha levels. We conclude that CINC-mediated hepatic neutrophil accumulation may not be necessarily associated with up-regulation of neutrophil adhesion molecules or elevated circulating TNF-alpha levels. Attenuation of hepatic neutrophil sequestration by anti-CINC antibody is likely based on blocking of the chemotactic activity of CINC and thus diminishing the chemotactic gradient established in the liver.

Pain due to nerve damage: are inflammatory mediators involved?

Damage to peripheral nerves often results in pain and hyperalgesia. We suggest that nerve damage causes an inflammatory response in which cells associated with the nerve release inflammatory mediators such as eicosanoids; these mediators may contribute to the hyperalgesia which results from nerve injury. The cell types most likely to be responsible include macrophages and postganglionic sympathetic neurones. A better understanding of the mechanisms involved should lead to improved therapies for neuropathic pain.

[Molecular and cellular mechanisms in inflammatory reactions]

Inflammation is a complex stereotypical reaction of the body expressing the response to damage of its cells and/or vascularized tissues. It is the body's reaction to invasion by an infectious agent, antigen challenge or even just physical, chemical, or traumatic damage. The development of inflammatory reactions is controlled by a number of cellular and molecular components. Leukocytes (namely neutrophils and macrophages) belong to the key inflammatory cells. Their accumulation in inflamed tissue results from adhesive interactions between leukocytes and endothelial cells within the microcirculation. The nature and magnitude of the adhesive interactions that take place within postcapillary venules are determined by a variety of factors, of which the contribution of different adhesion molecules (selectins, integrins, members of immunoglobulin superfamily) to leukocyte rolling, adherence, and emigration in venules is discussed. The main purpose of inflammation seems to be to bring fluids, proteins and cells from the blood into the damaged tissues for the elimination of injuring agent and triggering the healing and repairing processes. This is under the control of inflammation mediators which include vasoactive substances, proinflammatory and antiinflammatory cytokines, chemokines, acute phase reactants, bioactive lipids (prostanoids, platelet activating factor--PAF) and products of the plasma enzyme systems (complement, the coagulation clothing, kinin and fibrinolytic pathways) which are shortly reviewed. Several neuroendocrine hormones, neuropeptides, neurotransmitters and mainly glucocorticoids also play an important role of endogenous regulators of any inflammatory process. (Tab. 4, Fig. 1, Ref. 52.).

Major basic protein and topical administration of ketotifen in pollinosis under natural allergen provocation

In this study we investigated the potential relation among subjective symptoms, blood eosinophil counts and the levels of major basic protein (MBP) in serum throughout the pre- to postpollen season. In addition, we compared the effects of topical administration of ketotifen on these parameters between the prophylactic treatment group (n = 10) and the postsymptomatic treatment group (n = 10). We found that (1) the levels of MBP in serum during the season were significantly higher than those before the season and (2) the levels of the above three parameters in the prophylactic treatment group were significantly lower than those in the postsymptomatic treatment group during the season. It was concluded from these results that the action of MBP may be involved in the pathogenesis of allergic rhinitis. Furthermore, for the first time we provided evidence that topical ketotifen administration could suppress the systemic upregulation of the blood eosinophil count and MBP level in subjects with pollinosis.

[Postoperative homeostatic imbalance after trauma surgical interventions of various degrees in polytrauma]

The objective of this study was to evaluate and compare the derangement of body homeostatis and the inflammatory response after different types of traumatological operations in patients with multiple injuries. These were determined in a total of 60 operations. The procedures comprised osteosynthesis of the femur (n = 28), the pelvic girdle (n = 11) the spine (n = 8), and facial and basal skull reconstructions (n = 13). Specific and unspecific parameters of the inflammatory response were determined on the morning of the operation, immediately after the procedure, every 6 h on the 1st day and 48 h after the end of surgery. After all types of operations (pelvis, femur, spine, face/basal skull) significant alterations were observed for neutrophil elastase, C-reactive protein, interleukin 6, interleukin 8, antithrombin III, partial thromboplastin time and other parameters. The degree of postoperative changes differed significantly (Kruskal-Wallis test, P < 0.05) among the four types of operations for lactate, heart rate, PO2/FiO2 ratio and nitrogen excretion and showed a strong discriminating tendency for neutrophil elastase and C-reactive protein. The changes were most pronounced after operations on the pelvic girdle, followed by procedures in the femoral, spinal, and facial/basal skull regions. We conclude that a considerable inflammatory response and pronounced disturbance of body homeostasis follow traumatological operative procedures, varying in severity with the type of surgery. Several parameters allow quantitation of the surgical trauma and differentiation between different operations/regions. Further research should focus on the interrelationship between pre-existing preoperative inflammation and the additional trauma inflicted by surgery in patients with severe injuries.(ABSTRACT TRUNCATED AT 250 WORDS)

Current concepts of the etiology and pathogenesis of ulcerative colitis and Crohn's disease

Although the causes, events initiating and triggering inflammation, and the precise immunoregulatory defects of IBD are still not known, investigations have provided a better understanding of the mechanisms of perpetuation of inflammation, genetic susceptibility, tissue injury, and symptoms. Ulcerative colitis and Crohn's disease are related disorders that probably share susceptibility genes and have similar nonspecific inflammatory mediator profiles. These diseases, however, almost certainly have different causes and respond to different antigenic stimuli. It is probable that both ulcerative colitis and Crohn's disease represent heterogenic groups of diseases that share similar mechanisms of tissue damage but have different initiating events and immunoregulatory abnormalities. Rodent models demonstrate that a wide variety of initial injuries or perturbations of immunoregulatory pathways can lead to similar phenotypes of intestinal injury, and human studies show evidence of genetic heterogeneity. It is equally apparent from these models that initiating and perpetuating mechanisms are entirely distinct and that the intestine has a remarkable ability to heal. Chronicity of disease depends on continued exposure to toxic luminal components, most commonly of bacterial origin, and genetically determined host susceptibility. Precise mechanisms of differential genetic susceptibility remain unclear, but defective down-regulation of inflammation is consistent with clinical and experimental observations. The author proposes the following sequence of events (Fig. 9). Nonspecific intestinal inflammation can be induced by a wide variety of enteric infections or ingested toxins. Resultant increased mucosal permeability leads to enhanced uptake of toxic luminal bacterial products, which potentiate local injury. The vast majority of hosts respond to these injurious events by promptly down-regulating the inflammatory response and rapidly healing the mucosal damage without residual scarring. The genetically susceptible host, however, who lacks the ability to suppress the inflammatory response efficiently, has inappropriate amplification of the immune cascade. In response to constant exposure to phlogistic luminal constituents, these patients develop an unrestrained inflammatory response, leading to tissue destruction, chronic inflammation, and fibrosis. Thus, IBD is caused by a genetically determined defective down-regulation of inflammation driven by ubiquitous antigens. Luminal anaerobic bacterial antigens are the stimuli in Crohn's disease, but ulcerative colitis may be caused by functionally abnormal aerobic bacteria or primary defects in epithelial cell physiology. Spontaneous or therapy-induced remissions can be achieved, but the risk of reactivation of inflammation is high because of the frequent exposure to triggering episodes that can reignite the inflammatory cascade. [formula: see text] This theory suggests that the intestine is in a constant state of controlled inflammation, mediated by a balance between aggressive luminal forces and host protective mechanisms (Fig. 10). This delicate balance can be deranged by any number of environmental triggering events and is in dysequilibrium in IBD. Amplification of the inflammatory response activates effector cells and cascades of soluble inflammatory molecules, which mediate tissue injury and physiologic responses leading to symptoms of IBD. These relatively nonspecific events are the target of most current therapeutic agents, which can inhibit but not completely block intestinal inflammation because of the overwhelming number of parallel pathways involved. Specific inhibition of selected effector molecules is intellectually intriguing but is less likely to paralyze the inflammatory response during clinically apparent inflammation than is blockade of key immunoregulatory cells and molecules. Better understanding of initiating, perpetuating, and immunoregulatory mechanisms should provide more

Cysteinyl leukotrienes in asthma: old mediators up to new tricks

The cysteinyl leukotrienes have long been suspected to play a role in the pathogenesis of asthma. This speculation was based largely on their release in human lung following antigen challenge as well as their potent bronchoconstrictor activity. However, there is increasing evidence that the cysteinyl leukotrienes also produce several pro-inflammatory effects and alter the activity of neuronal pathways in the airways. Douglas Hay, Theodore Torphy and Bradley Undem review these recent data and discuss the therapeutic possibilities of cysteinyl leukotriene receptor antagonists and 5-lipoxygenase inhibitors.

[Pathogenesis of bronchopulmonary dysplasia]

Bronchopulmonary dysplasia of preterm infants has a multifactorial etiology. Pulmonary immaturity, oxygen toxicity, formation of oxygen radicals and mechanical lung trauma as well as additional factors (pulmonary hyperhydration, infection a.o.) may contribute to pulmonary damage. A pulmonary inflammatory reaction is thought to play a central role in the pathogenesis of chronic lung disease. It is characterized by the presence of inflammatory cells and various inflammatory mediators including proteases, chemoattractants, cytokines, leukotrienes and others. Due to the immaturity of several protective systems (antiproteases, antioxidants, surfactant system) the inflammatory response seems to be aggravated. Moreover, the magnitude and persistence of inflammation may eventually lead to pulmonary fibrosis.