PATHOGENESIS OF INFLAMMATION. II. IN VIVO OBSERVATIONS OF THE INFLAMMATORY EFFECTS OF ACTIVATED HAGEMAN FACTOR AND BRADYKININ

Beneficiary effect of a-lipoic acid supplementation on C-reactive protein level among adults

Purpose

Clinical evidence has suggested that alpha-lipoic acid (ALA), a potent antioxidant, seems to have some effects on inflammatory process. However, these results are equivocal. The purpose of this paper is to investigate the nature of association between ALA and serum C-reactive protein (CRP) level by pooling the results from clinical trial studies.

Design/methodology/approach

Relevant studies were identified by systematic literature search of PubMed/MEDLINE, Scopus, Web of Sciences and Cochrane library up to September 2016 for randomized controlled trials (RCTs) evaluating the impact of ALA supplementation on CRP. The pooled data were summarized as weighted mean difference (WMD) and 95 per cent confidence interval (CI). Effect sizes of eligible studies were pooled using random- or fixed-effects (the DerSimonian–Laird estimator) depending on the results of heterogeneity tests.

Findings

Of 212 papers, 15 were eligible RCTs according to inclusion criteria. The selected studies comprised 1,408 cases and 457 controls. The dose of ALA supplement ranged from 300 to 1,200 mg, and the duration of follow-up was from 1 to 48 weeks. ALA supplementation significantly reduced the levels of circulating CRP (WMD: −0.088, 95 per cent CI: −0.131, −0.045, p < 0.001) with significant heterogeneity (I2 = 73.4 per cent, p < 0.001). Populations with age younger than 50 years (PMD: −0.060 mg/dl), receiving doses less than 600 mg/day (PMD: −0.057 mg/dl), having cardiovascular disease (PMD: −0.105 mg/dl), hemodialysis (PMD: −0.209 mg/dl), diabetes (PMD: −0.021 mg/dl) and otherwise healthy subjects (PMD: −0.045 mg/dl) were sources of heterogeneity.

Originality/Value

This meta-analysis of RCTs suggests that ALA supplementation seems to significantly reduce circulating CRP level.

Effect of a kinin B2 receptor antagonist on LPS- and cytokine-induced neutrophil migration in rats

1 This study examines the involvement of kinins in neutrophil migration into rat subcutaneous air pouches triggered by lipopolysaccharide (LPS), as well as the putative roles played by kinin B(1) and B(2) receptors, tumour necrosis factor alpha (TNF-alpha), interleukin-1 beta (IL-1beta) and selectins in this response. 2 LPS (5 ng to 10 micro g cavity(-1)) injected into the 6-day-old pouch induced a dose- and time-dependent neutrophil migration which peaked between 4 and 6 h, and was maximal following the dose of 100 ng cavity(-1) (saline: 0.46+/-0.1; LPS: 43+/-3.70 x 10(6) cells cavity(-1) at 6 h). 3 Bradykinin (BK) (600 nmol) injected into the pouch of saline-treated rats induced only modest neutrophil migration (0.73+/-0.16 x 10(6) cells cavity(-1)). A more robust response to BK (3.2+/-0.25 x 10(6) cells cavity(-1)) was seen in animals pretreated with captopril, but this was still smaller than the responses to IL-1beta or TNF-alpha (15 pmol: 23+/-2.2 x 10(6) and 75 pmol: 29.5+/-2 x 10(6) cells cavity(-1), respectively). Nevertheless, the B(1) agonist des-Arg(9)-BK (600 nmol) failed to induce neutrophil migration. 4 HOE-140 (1 and 2 mg kg(-1)), a B(2) receptor antagonist, reduced LPS-induced neutrophil migration. HOE-140 also reduced the neutrophil migration induced by BK, but had no effect on the migration promoted by IL-1beta or TNF-alpha. des-Arg(9)-[Leu(8)]-BK, B(1) receptor antagonist was ineffective in changing neutrophil migration caused by any of these stimuli. 5 Neutrophil migration induced by LPS or BK was reduced by interleukin-1 receptor antagonist (IL-1ra) (1 mg kg(-1)), sheep anti-rat TNF serum (anti-TNF serum) (0.3 ml cavity(-1)), and the nonspecific selectin inhibitor fucoidin (10 mg kg(-1)). 6 TNF-alpha levels in the pouch fluid were increased by LPS or BK injection, peaking at 0.5-1 h and gradually declining thereafter up to 6 h. IL-1beta levels increased steadily throughout the 6 h period. HOE-140 markedly inhibited the rise in IL-1beta and TNF-alpha levels in pouch fluid triggered by both stimuli. 7 These results indicate that BK participates importantly in selectin-dependent neutrophil migration into the air pouch triggered by LPS in the rat, by stimulating B(2) receptors coupled to synthesis/release of TNF-alpha and IL-1beta.

Neutrophils contribute to sympathetic nerve terminal-dependent plasma extravasation in the knee joint of the rat

Infusion of bradykinin or 6-hydroxydopamine into the knee joint of the rat activates sympathetic postganglionic nerve terminals and increases plasma extravasation, a major sign of acute inflammation. Since bradykinin attracts and activates neutrophils in vivo and since neutrophils can release factors leading to plasma extravasation, we evaluated the contribution of the neutrophil to bradykinin-induced plasma extravasation. We report that perfusion of bradykinin into the rat knee joint produces a prolonged increase in plasma extravasation which is markedly reduced not only by sympathectomy (chronic pretreatment with systemic 6-hydroxydopamine) but also by depletion of circulating polymorphonuclear leukocytes (intravenous infusion of hydroxyurea combined with intraperitoneal glycogen). Depletion of polymorphonuclear leukocytes also reduced the plasma extravasation induced by intra-articular infusion of 6-hydroxydopamine, which acutely activates sympathetic postganglionic terminals. We next tested whether attraction of neutrophils into the joint, in the absence of bradykinin, was sufficient to enhance plasma extravasation. Although the classical neutrophil attractant glycogen attracted neutrophils into the knee joint, it did not increase plasma extravasation. Co-infusion of bradykinin and glycogen into the knee joint, however, provoked plasma extravasation that was significantly greater than that produced by bradykinin alone. We hypothesize, therefore, that bradykinin not only attracts neutrophils but also activates them, by an as yet undefined mechanism that requires the sympathetic terminal. The activated neutrophils release factors that lead to plasma extravasation. The next series of studies evaluated the role of the sympathetic nervous system in neutrophil attraction in vivo by bradykinin and glycogen. Since quantification of neutrophil attraction was not possible in the knee joint, we performed these studies in the peritoneal cavity, a site where neutrophils are readily attracted.(ABSTRACT TRUNCATED AT 250 WORDS)

Plasma prostaglandin E2 level in Kawasaki disease

Plasma levels of prostaglandin E2 and prostaglandin F2 alpha were determined in 15 patients in the acute and recovery stages of Kawasaki disease, 10 patients with anaphylactoid purpura, 16 with bacterial and viral infections and 10 healthy children. Plasma levels of prostaglandin E2 were markedly increased in the acute stage of Kawasaki disease, and these levels were decreased in the recovery stage. The prostaglandin F2 alpha/prostaglandin E2 ratio in the acute stage of Kawasaki disease was markedly decreased. Plasma levels of prostaglandin E2 in patients with anaphylactoid purpura, bacterial and viral infections were within the normal range. In Kawasaki disease which is associated with systemic vasculitis with a severe inflammatory reaction, prostaglandin E2 is considered to be more selectively produced and released than prostaglandin F2 alpha, suggesting that prostaglandin E2 plays an important role in the immunological and inflammatory reaction.

Skin blister immunocytology. A new method to quantify cellular kinetics in vivo

A method is described using tuberculin purified protein derivative (PPD) as a model to follow the in vivo cellular immune response. This combines induction of a local response, formation of skin blisters, and staining of the cells appearing in the sterile exudate over time, using standard cytopreparatory and immunoperoxidase techniques. Skin blisters were induced over sites previously injected intradermally with PPD or control saline using suction over a template on the forearm. The cells which appeared in the exudate at 24, 36, 48 and 72 h were collected on small cellulose filters which were divided into several parts. The cells on the filter segments were then stained using a biotin-avidin immunoperoxidase method with a panel of monoclonal antibodies, and with enzyme histochemical techniques. This allowed quantitative estimation over an extended period of total numbers of each cell type responding as a local expression of cellular immunity. The kinetics of an early, non-specific inflammatory response could be distinguished from the later immune response using total cell counts. Maximal cell counts correlated well with PPD induced induration at 48 h, showing an overwhelming predominance of mononuclear cells. Over 72 h, the number of non-specific esterase (NSE) positive cells (macrophage) declined while Leu4 positive cells (T cells) increased. OKT4 positive cells (T helper) outnumbered OKT8 positive cells (T suppressor) as the response developed. This method enables the direct quantitative assessment of cell populations arriving at the site of an immune response using a simple inexpensive technique which is painless, non-invasive and non-scarring.

Bradykinin causes a prolonged increase in skin microvascular permeability

Bradykinin is an endogenous inflammatory mediator, and its mechanism of action is incompletely understood. It is controversial whether bradykinin causes a sustained increase in microvascular permeability, or has only a transient effect. In anesthetized dogs intraarterial infusion of bradykinin (0.14 to 0.54 micrograms/kg/min) produced an immediate increase in flow of protein-rich, hindpaw lymph. After 210 min of bradykinin infusion lymph flow was threefold greater than baseline, lymph protein concentration remained doubled, and in a dose-related fashion bradykinin produced a sustained increase in lymph protein flux. Lymph flow was then further increased with venous hypertension, and after 4 hr lymph protein flux remained greater from the bradykinin paws than from the control paws. This sustained increase in protein flux indicates that bradykinin produces an increase in permeability at the microvascular membrane by a mechanism that is different from how the initial increase in permeability was produced.

Induction of acute cholecystitis by activation of factor XII

Acute, acalculous cholecystitis is seen among patients suffering with bacterial sepsis, burns, trauma, or cancer; clinical conditions that could lead to activation of factor XII-dependent pathways and result in inflammation of the gall bladder. To test this hypothesis, dogs were injected intravenously with ellagic acid or rutin, known polyphenol activators of factor XII, or with Escherichia coli endotoxin, also known to activate factor XII, and monkeys were injected intravenously with ellagic acid. In both species, in vivo activation of factor XII-dependent pathways with polyphenol activator resulted in rapid and selective development of acute vasculitis in the serosa and muscularis of the gallbladder and margination of polymorphonuclear neutrophils in pulmonary blood vessels. Intravenous injection of E. coli endotoxin in dogs resulted in necrosis and thrombosis of vessels that were especially severe in the serosa and muscularis of the gallbladder but also present in vessels of many other organs. These observations indicate that blood vessels of the gall bladder and, to a lesser degree, the lung are especially sensitive to injury consequent to in vivo activation of factor XII-dependent pathways and, in view of the common ingestion of plant polyphenols, may provide important insight into the pathogenesis of cholecystitis in man.

The leucocoyte disappearance reaction in non-immune acute inflammation

Injection of a variety of irritants (saline, ovalbumin, compound 48/80 and powdered glass) into the rat pleural cavity induced the disappearance of pleural leucocytes during the first two hours of the reaction. This phenomenon, termed the leucocyte disappearance reaction (LDR), was suppressed by treatment with the anticoagulants heparin and warfarin. The in-vitro incubation of normal, or inflammatory pleural leucocytes resulted in the deposition of dense interconnecting meshwork of fibrin only upon addition of fibrinogen to the culture medium. It is suggested from these results that the LDR is related to the clotting system, involving leucocyte-derived enzyme(s) analogous to those of the clotting system (e.g., tissue thromboplastin), which convert fibrogen to fibrin, resulting in cell-trapping and subsequent "disappearance" of pleural leuococytes. Similarities were observed betweeen the LDR in non-immune inflammation and the macrophage disappearance reaction of cell-mediated immunity. The significance of these phenomena in the inflammatory process, both immune and non-immune, is discussed.

Studies of intercellular invasion in vitro using rabbit peritoneal neutrophil granulocytes (PMNS). I. Role of contact inhibition of locomotion

Intercellular invasion is the active migration of cells on one type into the interiors of tissues composed of cells of dissimilar cell types. Contact paralysis of locomotion is the cessation of forward extension of the pseudopods of a cell as a result of its collision with another cell. One hypothesis to account for intercellular invasion proposes that a necessary condition for a cell type to be invasive to a given host tissue is that it lack contact paralysis of locomotion during collision with cells of that host tissue. The hypothesis has been tested using rabbit peritoneal neutrophil granulocytes (PMNs) as the invasive cell type and chick embryo fibroblasts as the host tissue. In organ culture, PMNs rapidly invade aggregates of fibroblasts. The behavior of the pseudopods of PMNs during collision with fibroblasts was analyzed for contact paralysis by a study of time-lapse films of cells in mixed monolayer culture. In monolayer culture, PMNs show little sign of paralysis of the pseudopods upon collision with fibroblasts and thus conform in their behavior to that predicted by the hypothesis.

Participation of components of the blood coagulation system in the inflammatory response

Images

The role of chemical mediators in the inflammatory response induced by foreign bodies: comparison with the schistosome egg granuloma

Both divinyl benzene copolymer (plastic) beads and schistosome eggs produce inflammatory reactions after intravenous deposition into the lung of a mouse. As reported previously, the schistosome egg granuloma is an immunologic reaction of the delayed hypersensitivity type; this inflammatory process is prevented by immunosuppressive measures, and characteristically demonstrates an anamnestic response. In contradistinction, the plastic bead granuloma appears to be characteristic of a foreign body reaction; it is unaffected by immunosuppressive measures and does not demonstrate an anamnestic response with repeated exposure. The data in this report suggest that the granuloma formation around plastic beads is a nonimmunologic reaction induced by chemical mediators of inflammation. This proposal is supported by the following findings: the plastic beads activate Hageman factor in normal human and mouse plasma; the plastic beads induce vascular permeability-enhancing activity as measured in guinea pig skin and kinin-like activity in normal human and mouse plasma that is dependent on Hageman factor; ellagic acid, an agent that activates Hageman factor in vivo and is reported to diminish kininogen by consumptive depletion, markedly depresses the plastic bead granuloma. These data are consistent with the idea that the plastic bead granuloma and perhaps other foreign body inflammatory reactions are in major part dependent on kinin formation. Ellagic acid also suppressed the schistosome egg granuloma, but not to the same degree as the plastic bead granuloma. The implications of this observation are discussed in the text. Silicosis and "blue velvet disease", pathologic processes associated with the deposition of silica and magnesium trisilicate, respectively, in the lung, and the induction of a foreign body reaction may also be dependent on the activation of chemical mediators of inflammation by the silica and magnesium trisilicate particles with immunologic mechanisms participating in only a minor way, if at all. The marked suppression of experimental silicosis and blue velvet disease in mice by ellagic acid supports this idea.

The anticoagulant activity of lysosomal cationic proteins from polymorphonuclear leukocytes

A cationic protein fraction from rabbit polymorphonuclear leukocyte lysosomes has been shown to exert a potent anticoagulant effect on human blood in vitro. The anticoagulant activity is detectable in the whole blood clotting time, the recalcification time of platelet-rich plasma, the prothrombin time, the partial thromboplastin time, and the thromboplastin generation test. The lysosomal cationic proteins do not inhibit any of the known specific procoagulants. They appear to inhibit clotting by blocking the formation of intrinsic thromboplastin possibly by interfering with the role of phospholipids in the reaction involving Factors V and X and calcium.

The acute inflammatory reaction in the rabbit ear chamber with particular reference to the phenomenon of leukocytic migration

Responses to injections of various materials into rabbit ear chambers were studied by in vivo microscopy. The acute inflammatory responses provoked by injections of antibody-antigen complexes were both quantitatively and qualitatively different from the responses obtained after injections of either homologous sera or the antigens alone. The sticking of leukocytes to endothelium during these responses occurred only in the venules draining the injection sites and was frequently present only on the sides of the venules towards the injection sites. An explanation of this finding was proposed in terms of absorption by the minute vessels related to the injection sites of postulated mediator(s) with specific activity on venular endothelium. Analysis of the rates and direction of movement of leukocytes during the reactions produced by the antibody-antigen complexes was performed with the aid of time-lapse cinemicroscopy. The leukocytes that were sticking to the venular endothelium frequently exhibited amoeboid locomotion within the vessels. Twice as many of these cells moved against the direction of blood flow as with it. This finding was discussed and an explanation proposed. A method for detecting a drift in the overall population of emigrated leukocytes within the inflamed tissue was described and revealed that four times as many amoeboid cells moved away from the injection sites as towards them. This result was discussed in the light of the in vitro chemotactic properties of antibody-antigen complexes demonstrated for rabbit leukocytes. An alternative explanation was proposed in terms of variation in the population density of these cells and their random movements and collisions. The rates of amoeboid movement of leukocytes during the acute inflammatory reactions produced by antibody-antigen complexes were similar to the rates found during turpentine inflammation and were compared to other published values.