Tumor necrosis factor-alpha-angiotensin interactions and regulation of blood pressure

OBJECTIVES

To compare the levels of tumor necrosis factor-alpha (TNF) produced by medullary thick ascending limb tubules (MTAL) obtained from normotensive and angiotensin II (Ang II)-dependent hypertensive rats and determine whether TNF participates in a mechanism that opposes elevation of blood pressure by Ang II.

DESIGN

We have previously demonstrated that in-vitro administration of Ang II increases production of TNF and prostaglandin E2 (PGE2) by the MTAL. We hypothesize that production of TNF and PGE2 by the MTAL is elevated in in-vivo models of Ang II-dependent hypertension and acts to modulate the pressor effects of Ang II. Thus, inhibition of TNF should disclose whether this cytokine acts to modulate Ang II-induced hypertension.

METHODS

MTAL tubules obtained from normotensive and Ang II-dependent hypertensive rats were isolated by enzymatic digestion and sieving. Tubules were cultured in the absence of exogenous Ang II. TNF and PGE2 levels were measured by enzyme-linked immunosorbent assay. Anti-TNF antiserum was administered intravenously to normotensive and Ang II-dependent hypertensive rats and their mean arterial pressures were measured.

RESULTS

Production of TNF and PGE2 was significantly greater in MTAL tubules isolated from Ang II hypertensive rats than it was in those from normotensive controls. Administration of anti-TNF antiserum exacerbated the Ang II-mediated increase in mean arterial pressure.

CONCLUSIONS

The higher levels of production of TNF and PGE2 by MTAL tubules isolated from Ang II hypertensive rats compared with those of normotensive controls are consistent with results of in-vitro experiments showing that administration of Ang II increases production of TNF and PGE2 by the MTAL. TNF and PGE2 participate in a counter-regulatory mechanism that opposes the pressor actions of Ang II.

Selective depletion of neutrophils by a monoclonal antibody, RP-3, suppresses dextran sulphate sodium-induced colitis in rats

Administration of dextran sulphate sodium to animals induces acute colitis characterized by infiltration of large numbers of neutrophils into the colonic mucosa, which histologically resembles human active ulcerative colitis. It has been reported that neutrophils and the reactive oxygen metabolites produced by them are involved in the progress of ulcerative colitis. This study was intended to clarify their roles by using this animal model. First, possible sources and species of reactive oxygen metabolites were determined using luminol-dependent chemiluminescence with addition of enzyme inhibitors and reactive oxygen metabolite scavengers. Next, to examine whether neutrophils and hypochlorous acid derived from them contribute to tissue injury, we administered RP-3, a monoclonal antibody capable of selectively depleting neutrophils, and taurine, a hypochlorous acid scavenger, to rats treated with dextran sulphate sodium. Addition of azide, taurine, catalase, superoxide dismutase and dimethyl sulphoxide into colonic mucosal scrapings significantly inhibited chemiluminescence production, but allopurinol and indomethacin had no effects. These results suggest that excessive hypochlorous acid, hydrogen peroxide, superoxide anion and hydroxyl radical are generated by the inflamed colonic mucosa. Intraperitoneal injections of RP-3 significantly suppressed bleeding, tissue myeloperoxidase activity, chemiluminescence production and erosion formation. On the other hand, administration of taurine tended to inhibit bleeding and erosion formation to some extent, although it could not significantly suppress them. These data suggest that neutrophils play an important role in the development of this colitis and that hypochlorous acid might be one of the causes of tissue injury induced by neutrophils.

[The effects of pulmonary rehabilitation combined with inspiratory muscle training on pulmonary function and inspiratory muscle strength in elderly patients with chronic obstructive pulmonary disease]

It has been suggested that pulmonary rehabilitation compined with inspiratory muscle training (IMT) might improve pulmonary function and respiratory muscle strength in elderly patients with chronic obstructive pulmonary disease (COPD). To test this hypothesis, inspiratory muscle strength (PImax), expiratory muscle strength (PEmax) and resting pulmonary function were measured in 13 elderly patients with COPD (aged 70.3 +/- 2.7 years). Inspiratory muscle training (IMT) was performed for 15 min twice a day, using a pressure threshold device, for a total of 12 weeks. The inspiratory threshold was set at 15% of maximal inspiratory pressure (PImax) for each individual. Pulmonary rehabilitation was performed for 12-h sessions over a 12-week period. Patients with COPD were assigned randomly to two groups: pulmonary rehabilitation combined with IMT (group A) (n = 7), and conventional pulmonary rehabilitation only (group B) (n = 6). Functional residual capacity (FRC) decreased significantly from 4.3 +/- 0.4 L at baseline to 3.9 +/- 0.4 L after rehabilitation (p < 0.01), Vp significantly increased from 4.6 +/- 0.8 L/sec at baseline to 5.1 +/- 0.7 L/sec after rehabilitation (p < 0.05) and the PImax increased significantly from 51.5 +/- 5.4 cmH2O at baseline to 80.9 +/- 7.0 cmH2O after rehabilitation (p < 0.02) in group A. However, these variables did not change in group B. There was no improvement in the 10-minutes walking distance of group A, but there was a significant increase in that of group B. It can be concluded that pulmonary rehabilitation combined with IMT improves pulmonary function and inspiratory muscle strength in elderly patients with COPD.

Transcription of human ABO histo-blood group genes is dependent upon binding of transcription factor CBF/NF-Y to minisatellite sequence

We have studied the transcriptional regulatory mechanism of the human histo-blood group ABO genes, and identified DNA cis-elements and trans-activating protein that control the expression of these genes which are important in blood transfusion and organ transplantation. We introduced the 5'-upstream sequence of ABO genes into the promoterless reporter vector and characterized the promoter activity of deletion constructs using transient transfection assays with gastric cancer cell line KATO III cells. The sequence just upstream of the transcription start site (cap site), and an enhancer element, which is located further upstream (between -3899 and -3618 base pairs (bp) from the transcription initiation site) and contains 4 tandem copies of a 43-bp repeat unit, were shown in gastric cancer cells to be responsible for the transcriptional activity of the ABO genes. DNA binding studies have demonstrated that a transcription factor, CBF/NF-Y, bound to the 43-bp repeat unit in the minisatellite. Functional importance of these CBF/NF-Y-binding sites in enhancer activity was confirmed by transfection experiments using reporter plasmids with mutated binding sites. Thus, transcriptional regulation of the human ABO genes is dependent upon binding of CBF/NF-Y to the minisatellite.

Homicide patterns in the Toyama Prefecture, Japan

Homicides occurring in the Toyama prefecture, Japan, during the past 10 years were reviewed. Between 1985 and 1994, 56 offenders committed 63 homicides. The mean death rate for homicide was 0.55 per 100,000. The ratio of male to female victims was 1:1, while 82% of the assailants were male and 18% were female. The victim and the assailant had a close family relationship in 58.7% of the cases. Dyadic death (homicide followed by suicide) accounted for 27% of all victims. Twenty-nine per cent of the victims were murdered by mentally unstable offenders, and in almost half (44%) of the cases the offender was convicted. Homicides during robbery were rare (only two cases), and there was only one homicide during sexual assault. Death was caused by blunt instrument injury in 38.1% of cases, asphyxia in 31.7%, stabbing in 17.5%, burns in 9.5% and shooting in 3.2% (only two cases). The majority (80%) of homicides occurred at the residence of the victim(s). None of the victims had a history of drug abuse. Social conditions in Toyama prefecture, and their possible relevance to local homicide patterns, are discussed briefly.

Mechanisms involved in Helicobacter pylori-induced interleukin-8 production by a gastric cancer cell line, MKN45

Accumulating evidence suggests an important role of interleukin-8 (IL-8) in Helicobacter pylori infection-associated chronic atrophic gastritis and peptic ulcer. We observed in this study that a gastric cancer-derived cell line, MKN45, produced a massive amount of IL-8 upon coculture with live H. pylori but not with killed H. pylori, H. pylori culture supernatants, or live H. pylori separated by a permeable membrane, indicating that IL-8 production requires a direct contact between the cells and live bacteria. Moreover, the tyrosine kinase inhibitor herbimycin but neither a protein kinase C inhibitor (staurosporine) nor a protein kinase A inhibitor (H89) inhibited IL-8 production by MKN45 cells cocultured with live bacteria, suggesting the involvement of a tyrosine kinase(s) in H. pylori-induced IL-8 production. In addition, coculture of H. pylori induced IL-8 mRNA expression in MKN45 cells and an increase in luciferase activity in cells which were transfected with a luciferase expression vector linked with a 5'-flanking region of the IL-8 gene (bp -133 to +44), indicating that the induction of IL-8 production occurred at the transcriptional level. This region contain three cis elements important for induction of IL-8 gene expression: AP-1 (-126 to -120 bp), NF-IL6 (-94 to -81 bp), and NF-kappaB (-80 to -70 bp) binding sites. Mutation of the NF-kappaB binding site abrogated completely the induction of luciferase activity, whereas that of the AP-1 site partially reduced the induction. However, mutation of the NF-IL6 binding site resulted in no decrease in the induction of luciferase activity. Moreover, specific NF-kappaB complexes were detected in the nuclear proteins extracted from MKN45 cells which were infected with H. pylori. Collectively, these results suggest that H. pylori induced the activation of NF-kappaB as well as AP-1, leading to IL-8 gene transcription.

Erythromycin modulates IL-8 expression in normal and inflamed human bronchial epithelial cells

Erythromycin (EM) and its 14-member macrolide analogues have attracted attention for its effectiveness in a variety of airway diseases, including diffuse panbronchiolitis (DPB), sinobronchial syndrome, and chronic sinusitis. However, its mechanisms of action remain unelucidated. We evaluated the effects of several antibiotics on IL-8 expression by normal and transformed human bronchial epithelial cells, an important source of this potent chemokine involved in cell recruitment into the airways. EM and clarithromycin (CAM) uniquely suppressed mRNA levels as well as the release of IL-8 at the therapeutic and noncytotoxic concentrations (% inhibition of IL-8 protein release: 25.0 +/- 5.67% and 37.5 +/- 8.99%, respectively, at 10(-6) M). The other antimicrobes, including a 16-member macrolide josamycin, showed no effect. Bronchial epithelial cells from very peripheral airways as well as from main bronchi were obtained from patients with chronic airway inflammatory diseases, and EM and CAM inhibited IL-8 release from these cells. Among five patients who underwent bronchoscopy before and after macrolide treatment, four showed decreased levels of IL-8 expression in airway epithelium as assessed by reverse transcription and polymerase chain reaction. Our findings showed these 14-member macrolides had inhibitory effect on IL-8 expression in human bronchial epithelial cells, and this new mode of action may have relevance to their clinical effectiveness in airway diseases.

Urinary kallikrein in Dahl-Iwai salt-sensitive and -resistant rats

This study was designed to evaluate the differences between the renal kallikrein in newly established Dahl-Iwai rats under salt loading and that of Sprague-Dawley rats (SD). Urinary kallikrein quantity and activity was markedly lower in Dahl-Iwai rats than in SD even during the control period. Moreover, kallikrein quantity and activity in Dahl-Iwai salt-sensitive rats (SS) were clearly diminished in comparison with salt-resistant rats (SR). The kallikrein activity/ quantity ratio was also lower in SS and SR than in SD during the control period. After salt loading, systolic blood pressure increased only in SS. Kallikrein activity in SS and SR, and kallikrein quantity in SS were increased, whereas those in SD did not change. Although the kallikrein activity/quantity ratio in SR reached the same level in SD after salt loading, that in SS was lower throughout the experiment. These results suggest that Dahl-Iwai rats are less able hereditarily to produce renal kallikrein and that there may exist structurally abnormal kallikrein that may have a lower activity. Different kinetics of renal kallikrein between SS and SR by salt loading might be explained by kallikrein inhibitors or abnormal kallikrein or nonkallikrein kininogenase. These different kinetics of renal kallikrein may play some role on blood pressure elevation in SS.

Intravenous immunoglobulin (IVIG) treatment of experimental colitis induced by dextran sulfate sodium in rats

We investigated the therapeutic effect and immunological action mechanism of IgG in experimental colitis induced by 3% dextran sulfate sodium in rats. Intravenous injection of homologous (rat) IgG (400 mg/kg per day) caused a significant suppression of occult blood discharge and ulcerative lesions in the colon, while no suppressive effect was observed in the case of heterologous (human) IgG. The positive effect of rat IgG on the lesions was also clearly shown by the histological examinations. Generation of proinflammatory cytokines, i.e. tumour necrosis factor-alpha (TNF-alpha) and IL-1alpha, in the lesions was found to be inhibited by administration of rat IgG. Little or no suppressive action was exerted by human IgG. Careful examination of recruited T cells and macrophages, both of which are thought to play important roles in the development of ulcerative colitis, indicated that rat IgG, but not its human counterpart, decreased the number of immunocompetent cells in colonic mucosa. Meanwhile, in an in vitro study, both forms of IgG were shown to suppress production of TNF-alpha and IL-1alpha from lamina propria mononuclear cells isolated from rat colon. These findings suggest that, mainly by suppressing recruitment of immunocompetent cells into the lesions, homologous IgG may reduce the occurrence of colitis.

Eosinophil adhesion to human bronchial epithelial cells: regulation by cytokines

BACKGROUND

Eosinophil infiltration into the airways and interaction with bronchial epithelial cells are important in the pathogenesis of asthma. The purpose of the present study was to elucidate the regulatory mechanisms of eosinophil adhesion to human bronchial epithelial cells.

METHODS

We cultured a human bronchial epithelial cell line, BEAS-2B, on a collagen-coated glass slide. Highly purified human eosinophils were added to each well to allow attachment to epithelium for 30 min. The number of attached eosinophils was counted.

RESULTS

Eosinophil adhesion to epithelial cells was increased when the BEAS-2B cells were pretreated with interferon-gamma (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha). Although IFN-gamma upregulated ICAM-1 expression as shown by flow cytometry, specific neutralizing antibody to ICAM-1 failed to block eosinophil adhesion. Dexamethasone significantly suppressed eosinophil adhesion to bronchial epithelial cells.

CONCLUSION

Eosinophil adhesion to bronchial epithelium was dynamically regulated by cytokines, and this process might be a target for therapeutic intervention in the treatment of asthma.

[Effect of imipenem/cilastatin combined with vancomycin for MRSA infection]

Therapeutic efficacy of the combined regimen, imipenem/cilastatin (IPM/CS) plus vancomycin (VCM), was examined in a total of 13 patients infected with MRSA (10 patients with pneumonia, 2 with sepsis and 1 with urinary tract infection). Based on the results of determination of FIC indices, in vitro combined effects were synergistic in 4 strains and additive in 3 strains. There was, however, no apparent correlation between the in vitro combined effect in terms of FIC index and clinical outcome. No side effects or abnormal laboratory findings were observed. The average daily doses of IPM/CS and VCM were 1.2 g and 1.25 g and the average administration periods were 17.5 and 14.9 days, respectively. The present results suggested that simultaneous use of IPM/CS and VCM at the standard doses could yield an enhancement of both bacteriological and clinical efficacies in treatment of the patients with MRSA infection.

[Interstitial pneumonia with Sjögren's syndrome: successful treatment with steroids and an immunosuppressant]

A 44-year-old woman was admitted to our hospital complaining of dyspnea. A chest X-ray film obtained on admission showed bilaterally shrunken lungs, and peripheral bundle-like and linear shadows. A chest CT scan revealed marked thickening of bronchovascular bundles and low lung volumes. Mild dryness of the mouth, and the results of a Rose-Bengal test, Schirmer test, and sialography led to the diagnosis of primary Sjögren's syndrome. Corticosteroid pulse therapy was followed by slight improvement. To determine the pathological diagnosis and to plan further therapy, video-assisted thoracoscopic lung biopsy was done. Examination of the biopsy specimen revealed alveolitis and infiltration of lymphocytes, which suggested active interstitial pneumonia. Therapy with corticosteroids and the immunosuppressant azathioprine was followed by marked improvement.

A novel antiallergic drug epinastine inhibits IL-8 release from human eosinophils

Eosinophils are believed to be one of the important sources of cytokines at the site of allergic inflammation. A novel antiallergic agent epinastine showed a dose- and time-dependent suppressive effect on IL-8, one of the chemokines for eosinophils, released from eosinophils isolated from atopic diseases. The time-dependent accumulation of IL-8 inhibited by cycloheximide and the evaluation of the IL-8 mRNA levels by reverse transcriptase-polymerase chain reaction suggested that its action occurred in the posttranscriptional processes. It was suggested that epinastine might prevent the autocrine cycle for recruitment of human eosinophils by inhibiting IL-8 release from these cells.

Increased IL-6 and IL-8 in bronchoalveolar lavage fluids (BALF) from patients with sarcoidosis: correlation with the clinical parameters

A variety of cytokines have been implicated in the pathogenesis of pulmonary sarcoidosis, but the exact roles of IL-6 and IL-8 are not yet clear. We studied these cytokine levels in BALF from patients with pulmonary sarcoidosis, idiopathic pulmonary fibrosis (IPF), systemic screlosis (SSc) with interstitial lung disease and control subjects. IL-6 and IL-8 levels were significantly elevated in sarcoidosis, IPF and SSc with interstitial lung disease compared with control subjects. Subjects with sarcoidosis had significantly increased levels of both cytokines compared with controls when the cytokine values were corrected by the total albumin content and the two cytokine levels correlated with each other (r = 0.876). BALF IL-6 levels correlated with percent lymphocytes and percent CD3+ cells. Moreover, when sarcoidosis patients were divided into three groups, those who needed steroid therapy or had progressive disease showed increased cytokine levels in BALF over stable or improved patients. These observations suggest that locally derived IL-6 and IL-8 were increased in sarcoidosis and correlated with activity of this granulomatous lung disease.

[Importance of interstitial lung disease in collagen vascular disease: analysis of outcome]

We studied length of survival and related clinical findings in 715 inpatients with collagen-vascular diseases (1984 through 1994), the diagnostic Kaplan-Meier analysis showed that patients with polymyositis/dermatomyositis and those with systemic sclerosis did not survive as long as those with other types of collagen-vascular disease. Of the patients who died 37% died of respiratory failure due to interstitial lung disease. Patients with interstitial lung disease had better outcomes than did those with idiopathic interstitial pneumonia: they were younger, had higher initial vital capacities, and fewer episodes of acute exacerbation of lung disease than did those with idiopathic interstitial pneumonia. Among patients with interstitial lung disease, those who died of polymyositis/dermatomyositis did so within 1 year, but those who died of systemic sclerosis lived longer. Interstitial lung disease is an important prognostic factor in collagen-vascular disease, and needs further evaluation.

A variant CD30 protein lacking extracellular and transmembrane domains is induced in HL-60 by tetradecanoylphorbol acetate and is expressed in alveolar macrophages

We identified and cloned cDNAs for two novel CD30 mRNAs of 2.3 kb that are induced by 12-O-tetradecanoylphorbol 13-acetate (TPA) in the human myeloid leukemia cell line HL-60. These transcripts were transcribed from the intronic region just upstream of the exon coding for the transmembrane domain of the CD30 protein. The shorter cDNA had a deletion of 54 nucleotides corresponding to the 3' region of the transmembrane domain of the CD30 and which was probably caused by alternative splicing. Translation of these transcripts appeared to start from the internal methionine codon at nucleotide position 289 that corresponds to that of 1612 in the CD30 cDNA, and encode a protein of 132 amino acid residues which corresponds exactly to the C-terminal cytoplasmic domain of CD30 protein. The calculated molecular mass of this variant CD30 (CD30v) protein was 14,087. Thus, the predicted CD30v protein retains most of the cytoplasmic region, but lacks the extracellular and transmembrane domains. Northern blots detected the expression of CD30v transcripts only in the lung and the TPA-stimulated HL-60 cell line. Translation of this mRNA in vitro produced a protein of 25 kD. Immunoblotting analysis with HCD30C1, a rabbit polyclonal antibody raised against the cytoplasmic domain of CD30 protein, detected proteins with an apparent Mr 25 kD expressed in TPA-stimulated HL-60 and COS-7 cells that were transfected with both types of CD30v cDNAs. Constitutive phosphorylation of the CD30v protein was demonstrated by in vitro labeling with [32P]. Immunohistochemical studies demonstrated CD30v protein was in alveolar macrophages. Cotransfection experiments using a kappa B-site-dependent reporter construct showed that CD30v can transactivate gene expression through activation of NF kappa B, as was noted on the authentic CD30 protein. Overexpression of the CD30v induced differentiation of HL-60 cells as evidenced by an increased NBT reduction activity. These observations provided new insights into the molecular heterogeneity and biological function of CD30 in myeloid cells.

T lymphocytes and silica-induced pulmonary inflammation and fibrosis in mice

BACKGROUND

Silica-induced pulmonary inflammation and fibrosis in animals provides a good model for chronic pulmonary inflammation and fibrosis. Although lymphocytes are implicated in the pathogenesis of pulmonary fibrosis, experimental models using silica-treated athymic nude mice have not been successful in showing the fibrogenic mechanism regulated by T cells. The aim of this study was to re-evaluate the role of T lymphocytes in the development of silicosis by comparing the response to silica administration of nude athymic mutants with that of euthymic animals.

METHODS

Suspensions of silica particles were transnasally administered to nude athymic mice (Balb/c nu/nu) as well as to their euthymic littermates (Balb/c nu/+). The degree of pulmonary inflammation and fibrosis was assessed on days 14, 28, and 56 based upon histological observation, analysis of collagen deposition in the lungs, and analysis of the cellular constituent, protein, and phospholipid content in the bronchoalveolar lavage fluid.

RESULTS

Histologically, athymic mice developed less severe interstitial pneumonitis than euthymic mice. In euthymic mice the lung hydroxyproline content increased with time after silica administration from 6.48 (0.38) micrograms hydroxyproline/mg dry lung weight on day 0 to 8.87 (0.41) micrograms/mg on day 56. A gradual increase in lung hydroxyproline content was also observed in athymic mice but the increase was significantly smaller than in euthymic mice (6.63 (0.43) micrograms/mg on day 0, 7.90 (0.19) micrograms/mg on day 56). Administration of silica resulted in an increase in the number of macrophages and neutrophils and in the total protein and phospholipid content of the bronchoalveolar lavage (BAL) fluid in both mouse strains. No significant difference was detected between athymic and euthymic mice in the numbers of macrophages, but the increase in neutrophils in the BAL fluid of athymic mice was significantly smaller than in euthymic mice on days 14 and 56. The total protein and phospholipid content of the BAL fluid from athymic mice was lower than that from euthymic mice.

CONCLUSIONS

T lymphocytes appear to be involved in the pathogenesis of silica-induced pneumonitis. Since pulmonary fibrosis develops even in nude athymic mice, T cells do not seem to play a primary part in fibrogenic response but they regulate, at least to some extent, the response of inflammatory cells and fibrogenesis of the lung.

[Outcome in patients with interstitial lung disease and polymyositis-dermatomyositis--a subgroup with poor prognosis]

To determine the role of interstitial lung disease (ILD) in the outcome of polymyositis-dermatomyositis (PM/DM), we studied 41 patients who had radiographic evidence of ILD among 51 patients with PM/DM. The patients were divided into 3 groups according to therapy: progressive, no change, or improved. Those classified as progressive had significantly higher rates of skin and lung symptoms, milder muscle symptoms, and lower levels of muscle enzymes than the other 2 groups, and none was positive for the anti-Jo-1 autoantibody. Nine patients with DM died of respiratory failure; they had low serum creatine kinase levels, no anti-Jo-1 antibodies, and a rapidly progressive course before death. Autopsy findings were obtained in 7 patients, and all had diffuse alveolar damage as the main pulmonary histological finding. A subgroup of patients with PM/DM-ILD have a poor prognosis, and ILD in PM/DM is an important prognostic factor.