Kinins in human disease

Bradykinin augments fibroblast-mediated contraction of released collagen gels

Bradykinin is a multifunctional mediator of inflammation believed to have a role in asthma, a disorder associated with remodeling of extracellular connective tissue. Using contraction of collagen gels as an in vitro model of wound contraction, we assessed the effects of bradykinin tissue on remodeling. Human fetal lung fibroblasts were embedded in type I collagen gels and cultured for 5 days. After release, the floating gels were cultured in the presence of bradykinin. Bradykinin significantly stimulated contraction in a concentration- and time-dependent manner. Coincubation with phosphoramidon augmented the effect of 10(-9) and 10(-8) M bradykinin. A B2 receptor antagonist attenuated the effect of bradykinin, whereas a B1 receptor antagonist had no effect, suggesting that the effect is mediated by the B2 receptor. An inhibitor of intracellular Ca2+ mobilization abolished the response; addition of EGTA to the culture medium attenuated the contraction of control gels but did not modulate the response to bradykinin. In contrast, the phospholipase C inhibitor U-73122 and the protein kinase C inhibitors staurosporine and GF-109203X attenuated the responses. These data suggest that by augmenting the contractility of fibroblasts, bradykinin may have an important role in remodeling of extracellular matrix that may result in tissue dysfunction in chronic inflammatory diseases, such as asthma.

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.

Effect of enalapril on the skin response to bradykinin in man

We tested the effect of oral enalapril on intradermal bradykinin to determine if kininase II inhibition occurs with therapeutic doses in vivo. Six normal male volunteers took either 5 mg enalapril orally or placebo on 2 days. Three hours later bradykinin was injected into the skin of the back in doses increasing from 10(-11) to 10(-9) M. Enalapril increased the bradykinin-induced wheal. Inhibition of kininase II may cause accumulation of endogenous bradykinin. This could be an important mechanism in the occasionally reported side effect of angioedema with the angiotensin converting enzyme (ACE) inhibiting group of drugs.

Bradykinin levels in inflammatory exudates

An enzyme immunoassay was used to measure the levels of bradykinin (BK)-like immunoreactivity in inflammatory exudates provoked by calcium pyrophosphate (CaPP) or carrageenin. BK-like immunoreactivity increased from 4 to 18 ng/ml in exudates provoked by CaPP and collected from 30 min to 3 h after induction of pleurisy. BK levels decreased progressively (from 16 to 3 ng/ml) in the samples collected at 4 and 6 h. BK levels did not increase in exudates provoked by carrageenin. Control samples of exudates provoked by CaPP but not treated with peptidase inhibitors [orthophenanthroline (OPH) or a mixture of EDTA-captopril-thioglycolic acid (ECT)] as well as samples containing one or the other peptidase inhibitors dissolved in saline, were also negative. The present results indicate that an increased production of kinins is detectable only in exudates induced by CaPP and not in those provoked by carrageenin. Our data also suggest that the kinins are rapidly metabolized, both in vitro (in the exudate sample) and in vivo (in the rat pleural cavity).

Monoclonal antibodies to bradykinin inhibit smooth muscle contractile action of bradykinin

Four hybridoma cell lines have been established that secrete monoclonal antibodies to nonapeptide bradykinin. Bradykinin coupled to ovalbumin, using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide as coupling agent, was used to immunize BALB/c mice. Spleen cells from the immunized animals were fused to P3-X63-AG8-653 mouse myeloma cells. The resultant hybrid cells were screened by enzyme-linked immunoassay for production of antibodies to bradykinin. Hybrids from four positive wells were subcloned by limiting dilution and expanded as ascites tumor into pristane-primed mice. All the four hybrids secreted monoclonal antibodies of IgG1 (k) isotype. Unlabeled peptides bradykinin, lysyl-bradykinin (kallidin) and methionyl-lysyl-bradykinin competed with the radiolabeled [Tyr1]kallidin for monoclonal antibody binding sites. These antibodies recognized preferentially either NH2- or COOH-terminals of the nonapeptide bradykinin and can distinguish between des-Arg1-bradykinin and des-Arg9-bradykinin. Bradykinin fragments smaller than eight residues were not recognized by these antibodies. Monoclonal antibodies BK-D6A5, BK-B6C9 and BK-A3D9 neutralized the smooth muscle contractile activity of bradykinin. An enzyme-linked immunoassay developed using these monoclonal antibodies showed the effective range of bradykinin determination between 5 and 150 ng.

The acute inflammatory process, arachidonic acid metabolism and the mode of action of anti-inflammatory drugs

Arachidonic acid is a polyunsaturated fatty acid covalently bound in esterified form in the cell membranes of most body cells. Following irritation or injury, arachidonic acid is released and oxygenated by enzyme systems leading to the formation of an important group of inflammatory mediators, the eicosanoids. It is now recognised that eicosanoid release is fundamental to the inflammatory process. For example, the prostaglandins and other prostanoids, products of the cyclooxygenase enzyme pathway, have potent inflammatory properties and prostaglandin E2 is readily detectable in equine acute inflammatory exudates. The administration of nonsteroidal anti-inflammatory drugs results in inhibition of prostaglandin synthesis and this explains the mode of action of agents such as phenylbutazone and flunixin. Lipoxygenase enzymes metabolise arachidonic acid to a group of noncyclised eicosanoids, the leukotrienes, some of which are also important inflammatory mediators. They are probably of particular importance in leucocyte-mediated aspects of chronic inflammation. Currently available non-steroidal anti-inflammatory drugs, however, do not inhibit lipoxygenase activity. In the light of recent evidence, the inflammatory process is re-examined and the important emerging roles of both cyclo-oxygenase and lipoxygenase derived eicosanoids are explored. The mode of action of current and future anti-inflammatory drugs offered to the equine clinician can be explained by their interference with arachidonic acid metabolism.

Do plain films of the chest and abdomen have a role in the diagnosis of acute pancreatitis?

Radiographs taken on the day of admission on 52 patients with acute pancreatitis have been compared with similar radiographs of 30 patients with acute cholecystitis and 22 patients with perforated duodenal ulcer. Two radiologists, who were unaware of the clinical features, looked specifically for the presence of 30 radiological signs. The only abdominal signs seen more frequently in acute pancreatitis were fluid levels in the stomach and duodenum, usually associated with dilatation. Duodenal abnormalities were seen in 42% of patients with acute pancreatitis and 21% of the controls (P less than 0.05) while gastric dilatation with a fluid level was seen in 29% of cases of acute pancreatitis compared with 12% of controls (P less than 0.05). Seventy per cent of the patients with severe acute pancreatitis had an abnormal chest radiograph on admission compared with 18% of those with mild disease. Left pleural effusion was the most common abnormality in severe pancreatitis (43%) and was seen significantly more often than in mild pancreatitis (P less than 0.01) and the control group (P less than 0.05). Therefore, consideration of the admission chest radiograph may help at an early stage to distinguish patients with severe pancreatitis from those with mild disease.

Cutaneous infections and disorders of inflammation

In 1908, the Nobel Prize in Physiology and Medicine was shared by Elie Metchnikoff and Paul Ehrlich. Their joint commendation acknowledged the vigorous debate which then existed and, in a sense, paved the way for our modern recognition that both cellular and humoral mechanisms might participate in immunity. Of Ehrlich's and Metchnikoff's many accomplishments, those concerning the basic nature of the inflammatory reaction suggested a clinical potential that has been realized only in the last decade. Central to their theories was the implication that normal inflammatory processes were of benefit to the host and that disordered inflammation was likely to lead to disease. Over the past decade or so, we have recognized an extensive set of diseases associated with primary or acquired deficiencies of inflammation, thus beginning to catch up to the genius of Ehrlich and Metchnikoff. Most, if not all, of these disorders demonstrate major cutaneous involvement in their clinical and biologic presentations. It is thus of essential importance that the dermatologist be familiar with this fascinating spectrum of disease, and it is to this end that this review is directed.

The effect of bradykinin on the electrical activity of rat jejunum

Bradykinin increased the potential difference across both the jejunum and colon of the rat. This effect was significantly reduced by indomethacin, suggesting that it was mediated by prostaglandins. The possibility that bradykinin may contribute to the diarrhoea of the carcinoid syndrome by inducing a net secretory state in the intestine is discussed.