LARGE MOLECULAR SUBSTANCES AS MEDIATORS OF THE INFLAMMATORY REACTION

Estimation of local vital reactions in severely burned tissues of guinea pig skin using C3a or C3a desArg as a marker

We observed changes in levels of anaphylatoxin C3a and/or its desArg (C3a/C3a desArg) peptides in the local site of severely burned skin tissues of guinea pigs using immuno-Western blotting methods. The C3a/C3a desArg peptides, which were probably generated during complement activation, were detected at significant levels from 30 min to 72 h following burn injury in an area limited to 3 mm from the wound edge. Levels of these peptides showed a tendency to be highest in that area 24 h after burn infliction. In postmortem injuries, C3a/C3a desArg peptides could not be detected. These peptides were detected in antemortem wounds up to at least 2 days at 22 degrees C and up to 3 days at 4 degrees C after death, although decreases in levels were found. Lower concentrations of these peptides were also found in postmortem burns in which postmortem hypostasis appeared strongly. These results suggest that, except for injuries of the area with obvious postmortem hypostasis, detection of C3a/C3a desArg can be useful for estimation of vital reactions in many kinds of wounds during inflammation.

A study on the vital reaction in wounded skin: simultaneous determination of histamine and polyamines in injured rat skin by high-performance liquid chromatography

This paper describes a modified method of simultaneous quantitative determination of histamine and polyamines (putrescine, cadaverine, spermidine and spermine) in incised skin wounds of rats using high-performance liquid chromatography (HPLC) with a strong-cation exchange column, shim-pack ISC-05/S0504P, employing a linear gradient of 0.7-2.5 M sodium chloride. There was scarcely any change in the histamine content of the vital wounds throughout the one week experimental period, although content decreased slightly in 1-h-old wounds. On the other hand, concentrations of putrescine and spermidine increased suddenly 12 h after wounding, and spermine content increased slightly in 4-day-old wounds. There was no post-mortem change in the histamine, spermidine and spermine contents of vital wounds allowed to stand at 25 degrees C up to 24 h after death. Based on these results, this HPLC method may be useful for the determination of wound age during the period of healing.

Cytokines and inflammation: modified "Miles-Wilhelm" criteria for assessing the likely roles of these substances in vivo

Cytokines (including lymphokines, interleukins, tumour necrosis factors, interferons and hemopoietic colony-stimulating factors) are a loose group of endogenous proteins which are presently being investigated for an increasingly wide range of bioactivities. Recently, cytokines have been suggested to mediate various aspects of inflammation, but the data on which these suggestions are based are often fragmentary and derive from limited experimental in vitro and in-vivo models of inflammation. Therefore, the roles of cytokines in the mediation of naturally occurring inflammatory lesions in man and animals remain unclear. This article traces the development of notions of endogenous mediators of inflammation over the last hundred years and reviews previously published ways of assessing the relevance of experimental data concerning mediators of inflammation to naturally occurring inflammatory lesions. Emphasis is given to the "criteria" advanced for this purpose by Miles and Wilhelm in the 1950s and 1960s, and additional criteria appropriate to the assessment of data concerning cytokines as mediators of inflammation are discussed.

Plasma exudation and asthma

Several pieces of evidence support the view that exudation of plasma into the airway wall and into the airway lumen occurs in asthma. Vascular leakage of plasma results from inflammatory mediator-induced separation of endothelial cells in postcapillary venules belonging to the tracheobronchial circulation. Whereas proposed mediators of asthma induce reversible leakage, several antiasthma drugs exhibit antileakage effects in animals and humans. Potential consequences of plasma exudation are many. Mucosal/submucosal edema might contribute to airway hyperresponsiveness. Plasma exudate in the airway lumen in asthma may contribute to sloughing of epithelium, impairment of mucociliary transport, narrowing of small airways, and mucus plug formation. Exuded plasma may cause airway inflammation and constriction because of its content of powerful mediators, and chemoattractant factors and plasma proteins may condition the inflammatory cells abundant in asthmatic airways to release mediators in response to stimuli that otherwise would be innocuous to the cells. It is concluded that inflammatory stimulus-induced increase in macromolecular permeability of the tracheobronchial microvasculature and mucosa may be a significant pathogenetic mechanism in asthma and that the postcapillary venular endothelium and airway epithelium that regulate leakage of plasma are important effector cells in this disease.

Identification of a protein in sera of normal humans that inhibits fibroblast chemotactic and random migration in vitro

Normal human serum contains a 230,000 Mr protein that inhibits fibroblast chemotactic and random migration. This serum inhibitor of fibroblast migration (SIFM) is a heat-stable, trypsin-sensitive protein with a pI of 4.8 that reversibly inhibits the random and chemotactic migration of fibroblasts in vitro. Although SIFM effectively inhibits the chemotaxis of fibroblasts to interstitial collagens, fibronectin, lymphocyte-derived chemotactic factor for fibroblasts, and serum-derived chemotactic factor, it does not alter the chemotactic migration of human peripheral blood neutrophils or monocytes, and does not act as a cytotoxin to human dermal fibroblasts. The SIFM appears to act through a cell-directed mechanism to alter the fibroblast's ability to migrate. Serum inhibitor of fibroblast migration may function in vivo to modulate fibroblast migration under physiologic and pathologic conditions.

Mechanisms for the involvement of high molecular weight kininogen in surface-dependent reactions of Hageman factor

The mechanisms by which human high molecular weight kininogen (HMKrK) contributes to the surface-dependent activation of the Hageman factor systems have been studied. The ability of various mixtures of purified human Hageman factor (coagulation factor XII), HMrK, prekallikrein, and kaolin to activate coagulation factor XI was determined with factor XIa (activated factor XI) clotting assays. Hageman factor, HMrK and prekallikrein were required for maximal rates of activation of factor XI. A certain optimal mixture of purified Hageman factor, HMrK, prekallikrein, and kaolin gave the same rapid initial rate of activation of purified factor XI as an equivalent aliquot of factor XI-deficient plasma. This suggests that potent, surface-mediated activation of factor XI in plasma is explicable in terms of Hageman factor, HMrK, and prekallikrein. By studying separately some of the surface-dependent reactions involving Hageman factor, it was found that HMrK accelerated by at least an order of magnitude the following reactions: (i) the activation of factor XI by activated Hageman factor; (ii) the activation of prekallikrein by activated Hageman factor; and (iii) the activation of Hageman factor by kallikrein. Stoichiometric rather than catalytic amounts of HMrK gave optimal activation of factor XI. These results are consistent with the hypothesis that HMrK and Hageman factor form a complex on kaolin which renders Hageman factor more susceptible to proteolytic activation by kallikrein and which facilitates the action of activated Hageman factor on its substrate proteins, factor XI and prekallikrein.

Clinical and physiologic studies of two siblings with prekallikrein (Fletcher factor) deficiency

Two siblings with hereditary Fletcher factor (prekallikrein) deficiency were studied for alterations of fibrinolysis, platelet function, skin inflammatory responses, permeability factor (PF/dil) formation and leukocyte chemotaxis. In vivo stimulation of fibrinolytic activity was normal; the bleeding time and platelet functions (adhesivity, aggregation, release reaction) were also normal. Both immediate (wheal-flare reaction to histamine, bradykinin, prostaglandin E1, physical agents) and delayed sensitivity skin test reactions were within normal limits. Migration of subjects' leukocytes to attractants in skin windows and in Boyden-type chambers was the same as that of control leukocytes. Serum complement components were essentially normal. One subject's leukocytes showed normal tissue factor production on stimulation by endotoxin, although prekallikrein deficiency did impair the endotoxin-stimulated generation of serum procoagulant activity. PF/dil caused increased vessel permeability in human skin; in vitro generation of PF/dil required both the Hageman factor and prekallikrein. The Fletcher factor-deficient subjects responded in a normal manner to PF/dil. Based on the Fletcher factor-coagulation assay, the biologic half-disappearance time of prekallikrein (after the transfusion of normal plasma in one of the subjects) was estimated at 35 hours. Therefore, these studies suggest that severe prekallikrein (Fletcher factor) deficiency in man is not associated with any clinically significant impairment in hemostasis, fibrinolysis, inflammatory responses or leukocyte function.

Further characterization of a factor from endotoxin-treated serum which releases histamine and heparin from mast cells

Upon incubation of hamster serum with bacterial endotoxin, a factor is produced which releases histamine and heparin from hamster mast cells and increases capillary permeability in guinea pig skin. The major histamine-releasing activity derived from hamster serum was characterized by gel filtration, found to have a molecular weight of approximately 60,000, and shown by electrophoresis to migrate with alpha-2- or beta-1-globulins. The ability to increase vascular permeability was not reversed by antihistamine. On the basis of these properties, the histamine-liberating factor generated by endotoxin in hamster serum differed significantly from known anaphylatoxins.

interactions between histamine and bradykinin assessed by continuous recording of increased vascular permeability

1. The responses of the cutaneous blood vessels of the guinea-pig to histamine and bradykinin have been studied in order to determine whether these factors mediate vascular changes by acting on different blood vessel receptors.2. In animals injected intravenously with bovine serum albumin labelled with phosphorus (32)P the reactions to histamine and bradykinin have been studied by continuously recording the local radioactive emission from the skin.3. Histamine increased the intensity of radioactive emission for 7-15 min. The level of radioactivity then remained almost constant for at least 1 hr. Bradykinin increased the rate of emission for 5-7 min but the radioactivity decreased by approx. 30% in 1 hr.4. The intensity of the response to histamine was markedly diminished in sites previously treated with either histamine or bradykinin, compared with the reaction in normal skin. However, a response of similar intensity to that in normal skin was evoked by histamine earlier in sites previously treated with bradykinin than in sites treated with histamine. By contrast, bradykinin evoked a similar reaction to that in normal skin, in sites previously treated with either histamine or bradykinin.5. The dissimilarity of the responses evoked by histamine and bradykinin suggests that there are two types of blood vessel receptors. One type may be activated by both histamine and bradykinin but becomes refractory to further stimulation with histamine. The other type of receptor is activated only by bradykinin and does not become refractory.

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.

Inflammatory changes in tumour vessels after systemic 5-hydroxytryptamine, bradykinin, kallikrein, or lysolecithin

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