Integrin-linked kinase acts as a pro-survival factor against high glucose-associated osmotic stress in human mesangial cells

BACKGROUND

Integrin-linked kinase (ILK) is a protein that plays an important role in extracellular matrix-mediated signalling. Recent studies implicated ILK dysregulation in the development of diabetic nephropathy. However, little is known about the significance of ILK up-regulation in response to high glucose in mesangial cells.

METHODS

The ILK messenger (m)RNA and protein expression in human mesangial cells were analysed with quantitative real-time polymerase chain reaction (PCR) and western blotting after exposure to either 100, 200, or 500 mg/dl glucose, or 100 mg/dl glucose + 400 mg/dl mannitol. Activation of protein Kinase B (PKB)/Akt was also determined by western blot analysis. Cells were transfected with ILK siRNA to determine the effects of ILK knockdown on PKB/Akt activation and cell death following treatment with high glucose or mannitol.

RESULTS

High concentrations of glucose or mannitol for three days significantly up-regulated ILK mRNA and protein expression (P < 0.05 vs 100 mg/dl glucose). In contrast, ILK expression in cells exposed to the same conditions for seven days was unaffected. The time course of PKB/Akt phosphorylation was similar to that of ILK protein expression. The siRNA-mediated down-regulation of ILK expression inhibited the elevation of PKB/Akt phosphorylation induced by high glucose treatment. Furthermore, the inhibition of ILK expression promoted high glucose- or mannitol-induced apoptosis.

CONCLUSION

The ILK may act as a pro-survival factor and play a role in protecting mesangial cells from hyperglycaemic osmotic stress.

[Anaerobic bacillus pyothorax with the production of gas and severe mediastinal shift]

A 62-year-old man was admitted with the complaints of chronic sputum, dyspnea, and general weakness. Chest X-ray and computed tomographic films disclosed severe mediastinal shift and left lung collapse due to the accumulation of fluid and gas in the left pleural space. A puncture of the thoracic cavity yielded a milk-coffee-like purulent pleural effusion with stool odor, suggesting pyothorax with pneumothorax or broncho-pleural fistula. Chest tube drainage was performed. The elimination of gas was transient; subsequently, no air leaks were observed during deep breathing, suggesting the absence of pneumothorax and broncho-pleural fistula. An anaerobic culture of pleural effusion was prepared and a Bacteroides species was isolated. These clinical findings indicated that the intrathoracic gas could have been produced by anaerobic bacilli. Systemic antibiotic chemotherapy with chest tube drainage achieved recovery. The production of gas in focal lesions is one noted symptom of anaerobic bacillus infection. However, to our knowledge, cases of anaerobic bacillus pyothorax generating large volumes of intrathoracic gas are rare.

[Miliary tuberculosis with atypical radiographic findings after aorto-coronary bypass surgery]

Dry cough and exertional dyspnea developed in a 78-year-old man after aorto-coronary bypass surgery for angina pectoris. Chest X-ray films showed small nodular shadows in the upper and middle fields of both lungs. The patient's condition was exacerbated despite treatment with antibiotics. Chest high-resolution computed tomography disclosed small nodular and reticulo-linear shadows predominantly in the interlobular septa and bronchovascular bundles. Transbronchial lung biopsy specimens revealed micro-granulomas with necrosis, suggesting miliary tuberculosis. Antituberculosis drugs were started and the patient's symptoms and radiographic findings gradually resolved. Cases of cellular immunosuppression have beer reported in patients following open-heart surgery that utilized antifical heart and lung apparatus. Such procedures, together with hemodialysis, deserve consideration as potential risk factors for miliary tuberculosis.

Activated eosinophils stimulate endothelin-1 release from airway epithelial cells by direct adherence via adhesion molecules

Endothelin-1 (ET-1), synthesized in airway epithelial cells, has a potent constrictive action on airway smooth muscle. In this study, we investigated the effect of eosinophils on ET-1 release from guinea pig cultured tracheal epithelial cells. Eosinophils with or without the activation were directly co-cultured with tracheal epithelial cells. Eosinophils activated by GM/CSF or IL-5 potentiated ET-1 release, but non-activated ones did not. Treatment of activated eosinophils with antibodies against macrophage-1 (Mac-1) and/or very late antigen-4 (VLA-4) suppressed the potentiated ET-1 release. However, inhibition of lipid mediators derived from activated eosinophils could not suppress the potentiated ET-1 release. Moreover, separated co-culture of activated eosinophils with tracheal epithelial cells using Millicell-CM had no effect on ET-1 release. These observations suggest that adherence of activated eosinophils to epithelial cells via adhesion molecules such as Mac-1 and VLA-4 was essential for potentiation of ET-1 release. Since presence of eosinophils in the epithelial layer has been commonly demonstrated in bronchial biopsies and autopsy specimens from patients with asthma, epithelial cells would be activated by adherence of eosinophils via adhesion molecules and potentiate ET-1 release in vivo.

[A case of isoniazid-induced pneumonitis]

A 55-year-old man was given a diagnosis of pulmonary tuberculosis. He was treated with isoniazid (INH), rifampicin (RFP), ethmbutol (EB) and pyrazinamide (PZA). After three weeks of treatment, he developed fever, dyspnea and dry cough. A chest X-ray taken at that time showed new reticulo-nodular shadows bilaterally and right pleural effusion. Ga scintigram showed strong uptake in both lungs. Transbronchial lung biopsy revealed alveolitis, suggesting drug-induced pneumonitis. Drug lymphocyte stimulation tests for INH, RFP, EB and PZA were negative. Because his symptoms were severe, all drugs were discontinued and daily predonisolone (30 mg) therapy was started. The symptoms and bilateral reticulo-nodular shadows soon resolved. The antituberculosis drugs were changed to streptomycin and levofloxacin, but these were ineffective. Therefore, EB, RFP and PZA, which only rarely induce pneumonitis, were carefully restarted in that order. Pneumonitis did not recur and the pulmonary tuberculosis improved. This clinical course suggests INH-induced pneumonitis.

[Clinical evaluation on causes of death in patients with pulmonary tuberculosis who died within one year after diagnosing as TB]

We evaluated the cause of death in patients with pulmonary tuberculosis who died within one year after diagnosing as tuberculosis. Of 325 bacillary patients during the past seven years, 43 (13.2%) died within one year. Twenty-three patients (53.5%) died directly of tuberculosis. In this group, 13 patients died in emaciation state. Most of them were aged and under a poor nutritional condition. Some patients died in spite of improvement of tuberculosis. The fact indicates the need to detect tuberculosis as early as possible in elderly persons, and treatment should be initiated immediately. Eight patients died of respiratory failure and their chest X-ray film showed wade-spread tuberculosis. Seven of the patients died in spite of initiating treatment within one month after the onset of symptoms. This fact suggests the importance of regular check up by chest X-ray to detect tuberculosis early. Two patients died of massive hemoptysis. They had an episode of bloody sputum and the laboratory examination showed anemia. On the other hand, 20 patients died due to coexisting diseases unrelated to tuberculosis. Ten patients died of malignant diseases and most of them were lung cancer. Two patients died of hepatic failure possibly caused by the adverse reaction of TB chemotherapy. The interval between the onset of the treatment and death was less than a month, and the fact suggests the need to observe carefully for adverse reactions especially in the early stage of treatment.

[A case of acquired immunodeficiency syndrome with disseminated Mycobacterium avium complex infection in which M. avium was isolated from bone marrow]

A 46-year old man was admitted to a hospital because of cough and dyspnea. He was diagnosed as interstitial pneumonia and was treated with prednisolone (PSL) and antibiotics. The symptoms improved temporarily but he soon developed acute respiratory failure and was transferred to our hospital. Chest X-ray and CT revealed ground-glass opacities in both lung fields. He was treated with methyl PSL, antibiotics, and antimycobacterial drugs but he died on the fourth hospital day. Retrospectively, hematologic laboratory examinations revealed that CD4+ cell count was 0/microliter and serological tests for HIV were positive by both EIA and Western blot methods. The culture of the bone marrow specimens was positive for mycobacteria other than M. tuberculosis, and the bacilli were identified as Mycobacterium avium. Thus, his disease was eventually diagnosed as disseminated Mycobacterium avium complex (MAC) infection. In the past reports, the diagnosis of disseminated MAC infection was most often made by blood cultures, however, the isolation of MAC from bone marrow is another sensitive and specific method for the diagnosis of this infection. In some cases, bone marrow examination would be useful to diagnose disseminated MAC infection.

[Four cases of tuberculous meningitis--clinical significance of pleocytosis with polymorphonuclears as the predominating cell type in CSF]

It has been well known that tuberculous meningitis cases have moderate pleocytosis with mononuclears as predominating cell type in cerebrospinal fluid (CSF). But there are some reports of tuberculous meningitis in which polymorphonuclears was predominant in CSF. In this study, we investigated differential cell counts of CSF in 4 tuberculous meningitis cases. In 3 of the 4 cases, the CSF had a polymorphonuclears preponderance on admission. The elevated ratio of polymorphonuclears seemed to relate with the severity of the disease, and the ratio declined promptly after the initiation of chemotherapy. The 2 cases, which showed extremely high ratio of polymorphonuclears, showed poor prognosis, one died and the other had the severe sequelae such as notable disturbances of consciousness with hydrocephalus. This study suggests that differential cell counts of CSF is a useful measures to predict the prognosis and to follow up patients with tuberculous meningitis. The finding of a polymorphonuclears preponderance in CSF would suggest the severity and activities of the disease and should be considered as an alarm sign in tuberculous meningitis.

Involvement of endothelins in immediate and late asthmatic responses of guinea pigs

To explore the pathophysiological roles of endothelin isopeptides and receptor subtypes in asthmatic responses, a guinea pig model for asthma was used to test the effects of antiendothelin (ET) serum and selective ET receptor antagonists for antigen-induced specific airway conductance changes as measured by whole-body plethysmography. In this model, all of the animals so far tested demonstrated both the immediate and late asthmatic responses. Although preimmune serum had no apparent effects, anti-ET antiserum suppressed the maximal reduction of specific airway conductance in both the immediate and late asthmatic responses, which suggested that ET(s) are involved in the pathophysiology of both the immediate and late asthmatic responses. The ETB selective antagonists, BQ788 and RES701-1, blocked the immediate asthmatic response but not the late asthmatic response, whereas the ETA antagonists, BQ123 and (Shionogi) 97-139, suppressed only the late asthmatic response without influencing the immediate asthmatic response. In vitro constrictive responses of isolated tracheas and bronchi to ET1 were inhibited mainly by BQ123 and BQ788, respectively, which suggested that distribution of ETA and ETB receptors for bronchoconstriction are topographically distinct along airways. Furthermore, thromboxane A2 and platelet activating factor (PAF) antagonists were effective in suppressing the late asthmatic response but not the immediate asthmatic response. Taken together, our present observations suggest that ET(s) influences pulmonary functions by constricting airway smooth muscle via ETB receptors during the immediate asthmatic response and by modulating pulmonary inflammation via ETA receptors during the late asthmatic response, respectively.

[A case of pulmonary tuberculosis associated with tuberculous fistula of anus]

A 39-year old male visited the hospital complaining of perianal pain, swelling and redness. Under the diagnosis of an anal abscess, drainage was performed repeatedly. As the wound failed to heal and fistulae were detected, excision of entire tract was performed. On histopathological examination of the resected fistulae, caseous necrosis, Langhans giant cells, and epithelioid cell infiltration were found and diagnosed as anal tuberculosis. Chest X-ray showed cavitary lesion with infiltrative shadow in right upper lobe. Acid-fast bacilli were positive in sputum, and the diagnosis of pulmonary tuberculosis was confirmed. Anti-tuberculosis therapy was immediately started with good response to treatment. As tuberculosis of anal region is so rare recently and there is no characteristic clinical picture, it is very difficult to diagnose it pre-operatively. In some cases such as ours, pulmonary or other tuberculosis is accompanied with anal tuberculosis. Therefore, accurate diagnosis of anal tuberculosis is needed to find other tuberculosis early. As anal tuberculosis is rarely diagnosed correctly before operation on the basis of the clinical picture, the histopathological examination of the excised fistula is mandatory for the correct diagnosis of anal tuberculosis.

[Antigen-induced dynamic alterations of endothelin receptors--guinea pig lung tissues]

Endothelins (ETs) are a family of peptides with potent constrictive activity in vascular and treacheal smooth muscle. The lung tissues are abundant in these peptides and their receptors; the peptides are produced by endothelial cells and airway epithelial cells, while its receptor is mainly located on smooth muscle. Therefore, it has been proposed that endothelins act in a paracrine fashion on nearby smooth muscle, thus regulating its tone. However, little is known about its physiological and pathological roles in pulmonary functions. We hypothesized that ET plays an important role in bronchoconstriction elicited by antigen challenge. In order to test this hypothesis, we investigated tracheal contractile activities and ET-receptors by employing an animal model in guinea pigs. Here, we report that guinea pigs who were sensitized followed by multiple challenges with the antigens had alterations of ET receptor(s) with respect to number and affinity.

[Enkephalinase activity in the guinea pig model of asthma]

Enkephalinase exists in airway epithelial cells, smooth muscle, and submucosa near glands, and cleaves tachykinins to inactive metabolites, thereby reducing there effects. To study the role of enkephalinase in asthmatic response, we measured its activity in guinea pig model of asthma. When compared with the control values, the enkephalinase activity was reduced during in immediate asthmatic response (IAR) and late asthmatic response (LAR). Compared with the control values (100%), each value was 79.7%, 73.4% in the trachea and 74.3%, 55.7% in the lung respectively. Tracheal muscle preparation taken from the control, IAR, and LAR groups were made and mounted in oxygenated modified Krebs-Ringer solution. The response was monitored by isometric transducer. Concentration response curves to NKA with or without phosphoramidon were obtained. The contractile responses of the LAR groups were enhanced in potency and efficiency. Phosphoramidon potentiated the NKA induced contraction of control and the IAR groups but was less potent in enhancing the contractile response in the LAR group, showing less enkephalinase activity in the LAR. These results suggest that the enkephalinase plays an important role in LAR. In LAR, the enkephalinase activity may be inhibited and the responsiveness of the smooth muscle to some bronchoconstrictor, such as tachykinins, may be increased.

Endothelins constrict guinea pig tracheas by multiple mechanisms

When tracheal rings isolated from guinea pigs were treated with endothelins (ETs), a dose-dependent constriction was observed and measured isometrically. ET potencies were ET-1 = ET-2 greater than ET-3. Dose-response curves of epithelium-denuded tracheas were shifted to the left by approximately one order of magnitude. Lung tissue contained saturable binding sites to 125I-labeled ET-1. These binding sites were replaced by ET-1 = ET-2 greater than ET-3. Because the airway tissue contained primarily ET-1 as measured by immunoassay after high-performance liquid chromatography separation, we investigated the mechanism of ET-1-induced tracheal constriction. Tracheal constriction induced by ET-1 required Ca++ in the medium. Because suppression of the contractile response by nicardipine and diltiazem was small, Ca++ entry appeared to be gated primarily through Ca++ channels rather than via voltage-dependent ones. FPL55712, SC47014A, indomethacin and OKY046 suppressed the dose-response curves, suggesting that lipid mediators are formed in response to ET-1. Diphenhydramine also altered dose-response curves, suggesting that histamine release from mast cells was partially responsible for the constriction. Pretreatment of tracheas with compound 48/80 resulted in suppression of the contractile responses. Furthermore, the combination of indomethacin, FPL55712 and diphenhydramine gave essentially identical effects. Our observations suggest that ET-1 provokes the contractile response of guinea pig tracheas not only by direct actions on smooth muscle but also by indirect actions through production of chemical mediators in mast cells and other inflammatory cells.

[Effect of enkephalinase inhibitor on endothelin-1 induced bronchoconstriction in guinea pigs]

Endothelin-1 (ET-1) is one of the most potent bronchoconstrictors in the guinea pig. The mechanism of its metabolism is still unclear. Phosphoramidon is known to be an enkephalinase inhibitor. We studied the effect of phosphoramidon on bronchoconstriction induced by ET-1. In the first in vitro study, a tracheal preparation was mounted in oxygenated Krebs-Ringer solution. The response was monitored by isometric transducer. Dose-response curves to ET-1 with or without phosphoramidon were obtained. Phosphoramidon potentiated ET-1 induced bronchoconstriction significantly. Next, the specific airway conductance (sGaw) was measured in conscious guinea pigs exposed to an aerosol of phosphoramidon or saline, followed by ET-1 aerosol inhalation. The ET-1 dose was increased by successively doubling the concentration. sGaw, after inhalation of phosphoramidon, was significantly reduced when exposed to ET-1. Phosphoramidon also potentiated ET-1 induced bronchoconstriction in vivo. Next, lung parenchymal tissues were prepared and placed in oxygenated Krebs-Ringer solution with or without phosphoramidon. ET-1 was added and incubated, and samples were injected into a high performance liquid chromatography column. Phosphoramidon inhibited an analysis of ET-1. These data suggest that enkephalinase plays a role in the break down of ET-1 in the airway of the guinea pig. Under the condition of decreased enkephalinase, ET-1 would potentiate bronchoconstriction.

ET-1 induced bronchoconstriction in the early phase but not late phase of anesthetized dogs is inhibited by indomethacin and ICI 198615

Intratracheally injected or aerosolized ET-1 induced quick and long-lasting bronchoconstriction of anesthetized mongrel dogs, thus increasing respiratory resistance(Rrs) with concomitantly decreasing dynamic compliance(Cdyn). As collateral resistance(Rcs) was measured postexposure to aerosolized ET-1 using wedged bronchoscope technique, ET-1 increased Rcs in a dose and time dependent manner. The increase attained maximal in 2 min and then, gradually declined. When the dogs were pretreated with the intravenous injection of 0.1 micrograms/kg ICI 198615, an inhibitor of lipoxygenase, the constrictive response was slowed down. Essentially similar results were also observed with the intravenous injection of 5 mg/kg indomethacin. Our observations suggest that the early phase of the ET-1 induced bronchoconstriction is mediated by eicosanoid metabolites.

[Endothelin-1 induced relaxation of guinea pig trachea after an anaphylactic reaction]

Endothelin-1 (ET-1), one of the most potent constrictors of airway smooth muscles, is reported to act on such inflammatory cells as mast cells and release several chemical mediators. We observed a transient relaxation response to ET-1 after an anaphylactic constriction of guinea pig tracheal smooth muscle. The guinea pig was actively sensitized with ovalbumin, and the tracheal strip was challenged with ovalbumin in vitro. ET-1 induced a transient relaxation followed by a constriction of the tracheal strip. The potency of the relaxation induced by 10(-9) M of ET-1 was 16.0 +/- 1.3%, compared to the response to isoproterenol (2 x 10(-5) M), and the duration of the relaxation was 7.2 +/- 0.7 minutes. Indomethacin (10(-6) M) had no effect on the response, indicated that prostaglandins have no relation. Mechanical denudation of the tracheal epithelium did not reduce the relaxation, but rather augmented it. These results indicate that ET-1 induces a relaxation, associated with a relaxation factor from non-epithelial tissue.

Endothelin-1-induced relaxation of guinea pig trachealis muscles

Our accompanying paper demonstrated that endothelin-1 (ET-1 constricts guinea pig airways directly and indirectly through mediators such as histamine and arachidonate metabolites. In order to exclude the role of mast cells in bronchoconstriction, we sensitized guinea pigs and challenged them in vitro with an antigen (ovalbumin). In the postanaphylactic trachea, ET-1 caused a transient relaxation followed by constriction. Such relaxation by ET was also observed in the tracheas constricted with carbamylcholine. The relaxation was completely blocked by nordihydroguaretic acid and AA861, lipooxygenase inhibitors, but not by indomethacin, a cyclooxygenase inhibitor, and FPL 55712, a leukotriene antagonist. Because the relaxation was not affected even in the presence of methylarginine, an inhibitor of NO synthesis, and superoxide dismutase, an enzyme for destroying NO radical, we concluded that ET-1 induces the relaxation of the tracheal muscles by producing lipooxygenase products, probably hydroperoxides of arachidonic acid.

Multiple mechanisms of bronchoconstrictive responses to endothelin-1

We investigated the mechanism of the endothelin-1 (ET-1)-induced bronchoconstriction of guinea pig tracheal smooth muscles. ET-1 contracted the tracheas in a dose-dependent manner. A combination of FPL55712 (leukotriene antagonist), diphenhydramine (histamine antagonist), and indomethacin (cyclooxygenase inhibitor) shifted the dose-response curve of ET-1 to the right and suppressed the maximal constriction. Azelastine, an antiallergic agent, exerted essentially similar results. The present data suggest that ET-1 constricts the airway smooth muscles not only by direct action on the tracheal smooth muscles but also by indirect action mediated through production of various chemical mediators in cells other than muscles.

Analysis of rRNA operons in Ureaplasma urealyticum

Physical maps of Ureaplasma urealyticum serotypes I and IV were obtained by differential hybridization of DNA restriction fragments to probes derived from the Escherichia coli rrnB operon. Each of the organisms contained two rRNA operons with genes linked in the typical order 5'-16S-23S-5S-3'. There was no BclI site in either of the operons, but there were several internal HindIII and EcoRI sites showing significant heterogeneity in their respective position in both of the serotypes.