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Reversal of established CD4+ type 2 T helper-mediated allergic airway inflammation and eosinophilia by therapeutic treatment with DNA vaccines limits progression towards chronic inflammation and remodelling.

Immunostimulatory DNA-based vaccines can prevent the induction of CD4(+) type 2 T helper (Th2) cell-mediated airway inflammation in experimental models, when administered before or at the time of allergen exposure. Here we demonstrate their efficacy in limiting the progression of an established response to chronic pulmonary inflammation and airway remodelling on subsequent allergen challenge. Mice exhibiting Th2-mediated airway inflammation induced following sensitization and challenge with group 1 allergen derived from Dermatophagoides pteronyssinus group species (Der p 1), a major allergen of house dust mite, were treated with pDNA vaccines. Their airways were rechallenged and the extent of inflammation assessed. In plasma DNA (pDNA)-vaccinated mice, infiltration of inflammatory cells, goblet cell hyperplasia and mucus production were reduced and subepithelial fibrosis attenuated. The reduction in eosinophil numbers correlated with a fall in levels of the profibrotic mediator transforming growth factor (TGF)-beta1 in bronchoalveolar lavage (BAL) and lung tissue. In addition to lung epithelial cells and resident alveolar macrophages, infiltrating eosinophils, the principle inflammatory cells recruited following allergen exposure, were a major source of TGF-beta1. Protection, conferred irrespective of the specificity of the pDNA construct, did not correlate with a sustained increase in systemic interferon (IFN)-gamma production but in a reduction in levels of the Th2 pro-inflammatory cytokines. Notably, there was a reduction in levels of interleukin (IL)-5 and IL-13 produced by systemic Der p 1 reactive CD4(+) Th2 cells on in vitro stimulation as well as in IL-4 and IL-5 levels in BAL fluid. These data suggest that suppression of CD4(+) Th2-mediated inflammation and eosinophilia were sufficient to attenuate progression towards airway remodelling. Immunostimulatory DNA may therefore have a therapeutic application in treatment of established allergic asthma in patients.

Allergens↗

Prolonged methylprednisolone treatment suppresses systemic inflammation in patients with unresolving acute respiratory distress syndrome: evidence for inadequate endogenous glucocorticoid secretion and inflammation-induced immune cell resistance to glucocorticoids.

Nuclear factor-kappaB (NF-kappaB) and glucocorticoid receptor-alpha (GR-alpha) have diametrically opposed functions in regulating inflammation. We investigated whether unresolving acute respiratory distress syndrome (ARDS) is associated with systemic inflammation- induced glucocorticoid resistance and whether prolonged methylprednisolone administration accelerates the suppression of systemic inflammatory indices and normalizes the sensitivity of the immune system to glucocorticoids. Patients enrolled into a randomized trial evaluating prolonged methylprednisolone administration in unresolving ARDS had serial plasma samples collected before and after randomization. In the plasma, we measured the concentrations of tumor necrosis factor-alpha (TNF-alpha), interleukins (IL) IL-1beta and IL-6, adrenocorticotropic hormone (ACTH), and cortisol. The ability of patient plasma to influence the NF-kappaB and GR-signal transduction systems of normal peripheral blood leukocytes (PBL) was examined. Patients treated with methylprednisolone had progressive and sustained reductions of TNF-alpha, IL-1beta, IL-6, ACTH, and cortisol concentrations over time. Normal PBL exposed to plasma samples collected during methylprednisolone exhibited significant progressive increases in all aspects of GR-mediated activity and significant reductions in NF-kappaB DNA-binding and transcription of TNF-alpha and IL-1beta. These findings provide support for the presence of endogenous glucocorticoid inadequacy in the control of inflammation and systemic inflammation-induced peripheral glucocorticoid resistance in ARDS. Prolonged methylprednisolone administration accelerated the resolution of both systemic inflammation and peripheral acquired glucocorticoid resistance in ARDS.

Adrenocorticotropic Hormone↗

Orbital inflammation and optic neuropathies associated with chronic sinusitis of intranasal cocaine abuse. Possible role of contiguous inflammation.

Three cases of long-standing intranasal cocaine abuse were associated with orbitopathy or optic neuropathy. All three cases were characterized by chronic sinusitis. Histopathologic examination of involved sinus and orbital tissues revealed chronic and acute nonspecific inflammation, with no evidence of unusual infections or of idiopathic midline destructive disease. In two of the cases, there was radiographic evidence of contiguous orbital inflammation associated with sinusitis. The inflammatory orbital process in these two cases was steroid responsive, but in one case recurrent inflammation occurred in response to steroid tapering. One patient suffered a complete loss of vision in the involved eye due to fulminant orbital inflammation and optic nerve dysfunction.

Adult↗

Acute phase reaction in rats: independent change of acute phase protein plasma concentration and macroscopic inflammation in primary rat adjuvant inflammation.

Experiments in rats suffering from primary acute adjuvant inflammation showed independent changes in serum acute phase protein concentration and macroscopic paw inflammation during antiinflammatory treatment: soybean trypsin inhibitor and horse-radish peroxidase caused antiinflammatory effects but simultaneously produced increased alpha 2 macroglobulin levels. On the other hand, cycloheximide significantly inhibited the increase of alpha 2 macroglobulin concentration in adjuvant inflammation, however, it had no antiinflammatory effect. All forms of treatment caused even some change in protein plasma levels of healthy rats which probably relates to an activation of cells producing interleukin-1, interleukin-6, and/or hepatocyte stimulating factor which trigger the synthesis of acute phase proteins in the liver. In inflamed rats, the snake venom batroxobin caused a significant decrease in the fibrinogen level whereas the paw swelling remained completely unaffected. Therefore, it seems to be doubtful whether acute phase proteins essentially contribute to the modulation of acute inflammatory reaction in primary rat adjuvant inflammation.

Acute-Phase Proteins↗

Seminal elastase-inhibitor complex, a marker of genital tract inflammation, and negative IVF outcome measures: role for a silent inflammation?

There is no consensus on whether and how male genital tract inflammation affects sperm fertilizing potential. The aims of this prospective study were to evaluate the elastase-inhibitor complex in seminal plasma (s-EI) level, a marker of male genital tract inflammation, in men undergoing in vitro fertilization (IVF) having no clinical signs of inflammation, and its association with semen characteristics, and the predictive role of s-EI for the outcome of IVF in terms of fertilization, embryo development to the blastocyst stage and pregnancy. The study involved 104 male partners of infertile couples with normal spermiogram undergoing IVF. On the day of oocyte retrieval, spermiogram and s-EI assessment using homogeneous immunoassay were performed. The outcome of IVF according to the s-EI level was assessed in 85 cycles with two or more oocytes. In 67 cycles embryos were cultured to the blastocyst stage. Spearman's and Pearson's correlation tests, chi-square test, and multiple linear and logistic regression analyses were used for statistical evaluation. Increased s-EI level (> or =250 microg/L) was detected in semen of 32% of men, and in 24% of men without leucocytospermia. We found an association between the s-EI level and semen leucocytes (r = 0.49, p = 0.004) but not with classical sperm characteristics. No correlation between the s-EI level and fertilization was observed. Increased s-EI levels were associated with a poorer blastocyst development rate (p = 0.03) and a higher number of arrested embryos (p = 0.04). Extended embryo culture to the blastocyst stage shows a negative effect of clinically silent male genital tract inflammation on embryo developmental potential.

Enzyme Inhibitors↗

Exploring inflammation in hemodialysis patients: persistent and superimposed inflammation. A longitudinal study.

BACKGROUND: Inflammation is frequently elevated, and seems to be episodic in hemodialysis (HD) patients. Whether, its episodic character is due to the temporal variability, in periods free of clinical events, of the inflammatory indices or due, to the acute phase response induced by common inflammatory stimuli, has not been investigated yet in a longitudinal study. This study explores inflammation forms, characteristics and causes which are probably related to the high cardiovascular disease (CVD) morbidity in HD patients. METHODS: In 37 HD patients, high-sensitivity C-reactive protein (hs-CRP), serum amyloid A (SAA) and interleukin-6 (IL-6) were weekly measured for 16 consecutive weeks. Inflammatory clinical events, in the week before every measurement, were recorded. Repeated measures ANOVA were applied for statistical analysis. RESULTS: Fifty-one of 533 patient-weeks were positive for a clinical event. Mean +/- SD (range) hs-CRP was 7.01 +/- 16.06 (0.2-169) mg/l for all the weeks of the study, 38.25 +/- 39.35 (2.1-169) mg/l for the weeks with clinical events and 3.70 +/- 3.86 (0.2-26.1) mg/l for the weeks free of events. Variations for SAA and IL-6 were similar. 'Clinical events' strongly influenced acute-phase proteins and IL-6 levels. The effect of the factor 'time' (as assessed by inflammatory indices variation in weekly repeated measurements) was significant for all the 3 indices measured, independently of the factor 'clinical events'. CONCLUSIONS: In periods free of clinical events, microinflammation characterizes HD patients and fluctuates in time. Inflammation due to common clinical events is added, periodically, to this microinflammation. The high level persistent microinflammation as well as the superimposed--due to clinical events--inflammation could be related to the CVD in these patients.

Adult↗

Nuclear factor-kappaB- and glucocorticoid receptor alpha- mediated mechanisms in the regulation of systemic and pulmonary inflammation during sepsis and acute respiratory distress syndrome. Evidence for inflammation-induced target tissue resistance to glucocorticoids.

To test the hypothesis that the interaction between nuclear factor-kappaB (NF-kappaB) and glucocorticoid receptor alpha (GRalpha) is a key pathogenetic mechanism regulating the progression of systemic and pulmonary inflammation in sepsis and acute respiratory distress syndrome (ARDS), we used an ex vivo model of systemic inflammation. Naïve peripheral blood leukocytes (PBL) were exposed to longitudinal (days 1-10) plasma samples from ARDS patients divided into three groups based on physiological improvement and clinical outcome by days 7-10: improvers, nonimprovers-survivors, and nonimprovers-nonsurvivors. In a separate group of nonimprovers-survivors, we correlated the severity of lung histopathology with the intensity of NF-kappaB and GRalpha nuclear staining in immunohistochemistry analysis of lung tissue obtained by open lung biopsy. We found that exposure of naïve cells to longitudinal plasma samples led to divergent directions in NF-kappaB and GRalpha activation that reflected the severity of systemic inflammation. Plasma samples from improvers with declining cytokine levels over time elicited a progressive increase in all measured aspects of glucocorticoid (GC)-induced GRalpha-mediated activity (p = 0.0001) and a correspondent reduction in NF-kappaB nuclear binding (p = 0.0001) and transcription of TNF-alpha and IL-1beta (regulated, GRalpha-driven response). In contrast, plasma samples from nonimprovers with sustained elevation in cytokine levels over time elicited only a modest longitudinal increase in GC-GRalpha-mediated activity (p = 0.04) and a progressive increase in NF-kappaB nuclear binding over time (p = 0.0001) that was most striking in nonsurvivors (dysregulated, NF-kappaB-driven response). By days 3-5, no overlap was observed between groups for NF-kappaB and GC-GRalpha nuclear binding. In immunohistochemistry analyses, lung tissues of patients with severe versus mild ARDS had a higher intensity of NF-kappaB nuclear staining (13 +/- 1.3 vs. 7 +/- 2.9; p = 0.01) and a lower ratio of GRalpha:NF-kappaB in nuclear staining (0.5 +/- 0.2 vs. 1.5 +/- 0.2; p = 0.007). In conclusion, we demonstrated that the ability of GC-GRalpha to downregulate NF-kappaB activation is critical for the resolution of systemic and pulmonary inflammation in ARDS. The findings provide a rationale for the use of prolonged GC treatment in early ARDS.

Adult↗

Neurogenic inflammation, vascular permeability, and mast cells. II. Additional evidence indicating that mast cells are not involved in neurogenic inflammation.

Activation of cutaneous sensory nerves induces vasodilatation and vascular permeability, i.e., neurogenic inflammation. We examined the histology and possible mast cell involvement in cutaneous neurogenic inflammation induced by electrical nerve stimulation (ENS). Three lines of evidence indicated that mast cells were not involved in rodent cutaneous neurogenic inflammation induced by electrical stimulation of the saphenous nerve. 1) Most mast cells (86.5% of all mast cells in the dorsal skin of the paw) were found in the deep dermis, whereas vessels developing increased vascular permeability after nerve stimulation (visualized with the supravital dye Monastral blue B, a macro-molecular tracer) were localized predominantly in the superficial dermis. By contrast, i.v. substance P, which also causes increased cutaneous vascular permeability, predominantly caused deeper vessels to leak. As analyzed by electron microscopy, the vessels that developed permeability in response to nerve stimulation, and were thereby stained with Monastral blue B, were found to be exclusively postcapillary venules. 2) Disodium cromoglycate (DSCG), a mast cell stabilizing compound, inhibited the cutaneous vascular permeability induced by intradermal injections of anti-IgE in a dose-dependent manner. By contrast, vascular permeability induced by ENS was not influenced by disodium cromoglycate treatment. 3) ENS and i.v. substance P both induced cutaneous vascular permeability in mast cell-deficient W/Wv mice, despite the fact that their skin contained only 4.7% of the mast cells present in their normal +/+ litter mates. The magnitude of ENS-induced vascular permeability responses in W/Wv mice were similar to control +/+ and BALB/c mice. This study supports our earlier observations suggesting that mast cell activation is not essential for the initial, vascular permeability phase of neurogenic inflammation in rodent skin.

Animals↗

Studies on the effect of inflammation on rat liver and serum sialyltransferase. Evidence that inflammation causes release of Gal beta 1 leads to 4GlcNAc alpha 2 leads to 6 sialyltransferase from liver.

Turpentine induced inflammation has been shown to elevate liver sialyl- and galactosyltransferase activities (Turchen, B., Jamieson, J.C., Huebner, E., and van Caeseele, L. (1977) Can. J. Zool. 55, 1567-1571; Lombart, C., Sturgess, J., and Schachter, H. (1980) Biochem. Biophys. Acta 629, 1-12). We now report that serum sialyl-, but not galactosyltransferase activities are significantly elevated in turpentine inflammation. A liver slice system is used to demonstrate that liver releases large amounts of sialyltransferase activity into medium after inflammation, whereas only a low level of galactosyltransferase activity is released. Studies with rat and human asialo-alpha 1-acid glycoprotein as acceptors, coupled with the use of lactose to confirm the nature of the linkages formed, showed that Gal beta 1 leads to 4GlcNAc alpha 2 leads to 6 sialyltransferase is released from liver in turpentine inflammation and is mainly responsible for the elevated sialyltransferase activity found in serum. The alpha 2 leads to 6 sialyltransferase is exhibiting the properties of a typical acute phase reactant.

Animals↗

Role of angiotensin-converting enzyme in Bacille Calmette-Guérin-induced granulomatous inflammation. Increased angiotensin-converting enzyme levels in lung lavage and suppression of inflammation with captopril.

Lung lavage levels of angiotensin-converting enzyme (ACE)-like activity were increased in C57BL/6 mice with Bacille Calmette-Guérin (BCG)-induced chronic granulomatous pulmonary inflammation and splenomegaly. Contrariwise, ACE activity was not increased in lung lavage fluids of CBA mice that developed only minimal pulmonary inflammation in response to BCG. ACE-like activity correlated with the intensity of inflammation and Captopril, a specific competitive inhibitor of ACE activity, markedly suppressed the induction and maintenance of the BCG-induced inflammatory response in both lungs and spleen. It was necessary, however, to provide sustained treatment with large doses of Captopril in order to reduce the inflammatory response. After a single intraperitoneal injection of Captopril, ACE levels in lung lavage of BCG-injected mice were reduced but returned to preinjection levels or greater within 24 h. The highest dose of Captopril was more effective in reducing the lung fluid level of ACE in BCG-inflamed lungs. This suggests that sustained daily injections of Captopril were necessary to maintain reduced ACE levels. In vitro studies indicated that high concentrations of Captopril did not affect macrophage mobility or chemotactic activity for macrophages. Thus, ACE may act as a molecular mediator of BCG-induced granulomatous inflammation in the lung.

Animals↗

Heterogeneity of airway inflammation in persistent asthma : evidence of neutrophilic inflammation and increased sputum interleukin-8.

STUDY OBJECTIVES: To identify the characteristics of airway inflammation in persistent asthma and to examine the role of neutrophilic inflammation in noneosinophilic persistent asthma. METHODS: Nonsmoking adults (n = 56) with persistent asthma and healthy control subjects (n = 8) underwent hypertonic saline solution challenge and sputum induction. Selected sputum portions were dispersed with dithiothreitol and assayed for total cell count, cellular differential, supernatant eosinophil cationic protein (ECP), myeloperoxidase, and interleukin (IL)-8. RESULTS: We identified two distinct inflammatory patterns. Typical eosinophilic inflammation occurred in 41% of subjects, whereas the remainder exhibited noneosinophilic asthma (59%). Both neutrophil percentage and absolute neutrophil counts were increased in subjects with noneosinophilic asthma (64%, 283 x 10(6)/mL) compared to eosinophilic asthma (14%, 41 x 10(6)/mL) and control subjects (34%, 49 x 10(6)/mL; p = 0.0001). Myeloperoxidase was elevated in both noneosinophilic (280 ng/mL) and eosinophilic groups (254 ng/mL) compared with control subjects (82 ng/mL; p = 0.002). Sputum IL-8 levels were highest in subjects with noneosinophilic asthma (45 ng/mL) compared to eosinophilic asthma (9.6 ng/mL) and control subjects (3.5 ng/mL; p = 0.0001). Neutrophils correlated with IL-8 levels (r = 0.72). ECP was highest in subjects with eosinophilic asthma (2,685 ng/mL) compared with noneosinophilic asthma (1,081 ng/mL) and control subjects (110 ng/mL; p = 0.0001). CONCLUSION: Induced-sputum analysis in persistent asthma identifies two different inflammatory patterns. The most common pattern is noneosinophilic, associated with a neutrophil influx and activation, which may be mediated by IL-8 secretion. There is heterogeneity of airway inflammation in persistent asthma, which indicates differing mechanisms and may impact on treatment responses.

Adult↗

Effects of experimental joint inflammation on bone marrow and periarticular bone. A study of two types of arthritis, using variable degrees of inflammation.

The effects of joint inflammation on bone marrow and periarticular bone were studied in mice using antigen-induced arthritis and zymosan-induced arthritis as models for an immune and a non-immune-mediated chronic inflammation. To allow for a comparison of the two types of arthritis care was taken to induce comparable degrees of inflammation as evaluated with 99mTechnetium uptake and histology. The antigen-induced arthritis caused a significant suppression of the mitotic activity in the bone marrow close to the inflammatory focus during the first days of arthritis. The zymosan-induced arthritis did not produce alterations of the bone marrow activity. Both types of arthritis were able to induce long-lasting and irreversible damage to cartilaginous and bony structures. Apposition of bone was observed in both types of arthritis although much earlier in the antigen-induced arthritis. The apposition of bone was found to emerge largely from the periosteum and not from the epiphyseal plates, as shown by 125I-deoxyuridine autoradiography. Qualitative and quantitative differences suggest that joint inflammation which is immunologically mediated, results in more severe (peri)articular tissue damage than a non-immunological arthritis.

Animals↗

On the relation of inflammation to the chemical constitution of injurious agents. On the pharmacology of inflammation.

Changes characteristic of an inflammatory reaction caused by the injection of an injurious agent into the peritoneal cavity were measurable by the quantity of peritoneal fluid, by the number of leucocytes that entered the cavity, and by the abundance of exuded protein. Inflammation increased in severity along with ion dissociation and increase of the valence of electrolytes. With chlorides, sulfates, and nitrates it increased in each instance with the valence of their basic ions. The reactions caused by sodium chloride, sodium sulfate, and sodium citrate increased with the valence of their acid ions. Salts of heavy metals which fix and precipitate proteins caused more active inflammation than did other electrolytes. Histamine and arginine caused active inflammatory reactions with similar characteristics. The amino compounds, urea, citrulline, and creatinine, glycine, alanine, histidine, arginine, and histamine, produced inflammatory reaction in the order of severity with which, in foregoing experiments, they had caused necrosis when injected into the dermis. The acids and alkalis that were tested caused active inflammation when their acidity approached pH 1 or their alkalinity pH 11 respectively, but with approximate neutrality the inflammatory reaction became scant. These changes were in accord with the extent of necrosis when acid or alkalis, in foregoing experiments, were injected into the dermis. When histamine or arginine combines with hydrochloric acid to form histamine dihydrochloride or arginine monohydrochloride alkalinity is lost and inflammatory reactions caused by the hydrochlorides are relatively mild. The characteristic changes which accompany histamine and arginine do not occur. The combination of histamine with phosphoric acid to form histamine acid phosphate has similar relation to histamine. Inflammatory reactions caused by monobasic, dibasic, and tribasic sodium phosphate increased in activity in accord with increasing alkalinity referable to the basic ions of these salts. The activity of inflammatory reactions has been found to vary in accord with the chemical constitution of the injurious agents that have been tested.

Acids↗

[Tissue factor expression at the site of inflammation: a cross-talk between inflammation and the blood coagulation system].

Recent studies have revealed a close association of the blood coagulation system with inflammation and immune reactions. The products of the cascade reaction of blood coagulation can work as inflammatory mediators or immune modulators, and, vice versa, some inflammatory or immune stimuli are linked to induction of blood coagulation. First, tissue factor (the blood coagulation initiator), the monocyte/macrophage tissue factor expression regulatory factors associated with inflammation and immune reactions, and the assembly of coagulation factors on leukocytes were reviewed. Second, evidence of leukocyte tissue factor expression and subsequent fibrin deposition were demonstrated at sites of infection or allergic reactions, using immunohistochemical staining. Third, the progress in the investigation of thrombin was reviewed from the viewpoint of its effects on inflammation (vascular permeability enhancement, leukocyte chemotaxis, chemical mediator release, etc.) and immune reactions (T-cell proliferation, cytokine production, etc.). The evidence presented here indicates a cross-talk between blood coagulation and inflammatory and immune reactions, suggesting that the products of the clotting reaction (e.g., thrombin) in lesions are real-time markers of inflammatory diseases.

Biomarkers↗

Morphological characteristics of total joint arthroplasty-derived ultra-high molecular weight polyethylene (UHMWPE) wear debris that provoke inflammation in a murine model of inflammation.

It is recognized that the chronic inflammation in peri-prosthetic tissue that contributes to implant failure frequently is provoked by the presence of wear debris. Some wear debris is inevitable because of the nature of the prosthesis, but not all patients develop severe inflammatory responses. The precise factors that mediate the severity of tissue inflammation to wear debris has yet to be fully defined. Because wear debris retrieved from peri-prosthetic tissue consists of a heterogeneous mixture of materials with various sizes and shapes, this study evaluated the influence of two major physical aspects of ultra-high molecular weight polyethylene (UHMWPE) wear debris (shape and surface texture) using a model of tissue inflammation. UHMWPE debris particulates recovered from 50 peri-prosthetic tissue samples were examined by scanning electron microscopy and categorized into four groups based upon aspect ratio and surface texture of the material. The four groups were defined as: 1) smooth and globular, 2) smooth and fibular, 3) rough and globular, and 4) rough and fibular. Histological analysis and ELISA assays were conducted to evaluate variations in cellular responses and cytokine production between the groups. The strongest expression of tumor necrosis factor alpha and interleukin-1 beta was found in tissues exposed to UHMWPE debris with both a rough surface texture and fibular shape, and this response was significantly elevated over debris particles with a smooth surface texture and globular shape. The data suggest that both shape and texture influence the severity of specific inflammatory responses and that rough debris surface texture exerts a marked effect on adverse tissue responses when combined with particles that have a sharp, elongated shape.

Animals↗

Rabbit vascular endothelial adhesion molecules: ELAM-1 is most elevated in acute inflammation, whereas VCAM-1 and ICAM-1 predominate in chronic inflammation.

Activation of the microvasculature is a major component of the inflammatory response. During inflammation the vascular endothelium not only becomes more permeable to plasma proteins but also develops adhesion molecules that initiate the local immigration of leukocytes. We describe herein the in vivo changes in the three major vascular adhesion molecules during the development and healing of two types of rabbit dermal inflammatory lesions: (1) acute lesions produced in rabbits by the topical application of 1% sulfur mustard (SM, the military irritant/toxicant); and (2) chronic (immune-mediated) lesions produced in rabbits by intradermal injections of Mycobacterium bovis (BCG), the vaccine strain of tubercle bacillus. In each case, frozen tissue sections were made from lesions of various ages and stained immunohistochemically for von Willebrand (vW) factor to measure the total functional microvasculature. The sections were also stained immunohistochemically for the vascular endothelial adhesion molecules ICAM-1, ELAM-1 (E-selectin), and VCAM-1, and for the leukocyte ligands for ICAM-1: LFA-1 (CD11a/CD18) and Mac-1 (CD11b/CD18). Infiltrating monocytes and lymphocytes expressed the LFA-1 ligand and infiltrating PMN expressed the MAC-1 ligand. The area of stained microvasculature per square millimeter of tissue section was determined with the use of a computerized image analyzer. Edema and cell infiltration spread apart the microvessels, changing the number of microvessels per square millimeter of tissue section. Three methods of assessing such changes are presented. In SM lesions, endothelial ICAM levels were decreased from normal by about 50% at 1 and 2 days (when the lesions reached their peak size) and returned to normal at 3 and 6 days (during the healing process). ELAM rose in peak SM lesions and remained high during healing. VCAM levels, however, were only elevated in the 6-day (almost healed) lesions. In BCG lesions the levels of endothelial ICAM and VCAM (and to a lesser extent ELAM) were increased at 9 days and remained so as the size of the lesions peaked at 23 days. During the healing phase at 37 days, the elevated ICAM and VCAM levels decreased but the slightly increased ELAM levels persisted. These findings indicate that ELAM plays a major role in acute inflammation and that VCAM and ICAM play major roles in chronic inflammation. VCAM is known to be monocyte and lymphocyte selective.

Acute Disease↗

Swine as a model of skin inflammation. Phospholipase A2-induced inflammation.

A predictive animal model of skin inflammation is needed for the development of potential therapeutic agents. The existing models of inflammation rely on animals whose skin physiology or biochemistry differs significantly from human. The objective of this investigation was to evaluate the swine as a potential model of inflammation, because its skin has been recognized to exhibit morphologic and functional similarities to human skin. In the swine, an inflammatory response was produced following intradermal injection of snake venom phospholipase A2 (PLA2). This response was characterized by transient erythema (2-3 h) and microscopic changes of cell infiltration, epidermal hyperplasia, and dermal damage, which were apparent two days after PLA2 and peaked by day 7. In general, these microscopic changes persisted up to 21 days. Treatment with the antiinflammatory steroid, betamethasone dipropionate (Diprolene), gave a significant reduction of the inflammatory responses. Heat-inactivated PLA2, ovalbumin, or saline did not provoke this reaction, although PLA2 inactivated by bromophenacyl bromide alkylation did produce an inflammatory response. The alkylated PLA2 was also able to provoke an inflammatory response in the mouse paw edema assay. These results demonstrate that PLA2 can stimulate an inflammatory response in the swine skin, but that phospholipid hydrolytic activity is not required.

Administration, Topical↗

Inflammation-mediated osteopenia (IMO) during acute inflammation in rats is due to a transient inhibition of bone formation.

Local inflammation was induced in rats through the subcutaneous injection of magnesium silicate. Trabecular bone volume of the tibia decreased progressively during a 3 week observation period following the inflammatory stimulus. The trabecular bone surface covered with osteoblasts was strikingly reduced during the first week but had normalized by the end of the third week. Calcification rate in the cortical bone of the tibia was reduced with a parallel reduction in endosteal osteoid seam width. Both calcification rate and tetracycline double-labeled surface of vertebral trabecular bone were reduced during the first 2 weeks. Neither total bone resorption surface nor active bone resorption surface were increased. There was a decrease in osteoclast numbers/mm2 bone tissue associated with decreasing bone volume. Our data demonstrate a transient inhibition of bone formation during acute inflammation in the rat and indicate that changes in osteoblast function are part of the acute phase response following local inflammation.

Acute-Phase Reaction↗