ABSTRACT
Background and objective: The mechanism by which iodopovidone achieves pleurodesis is unknown. This study investigated whether iodopovidone is as effective as doxycycline in producing ...pleurodesis and whether systemic corticosteroids diminish its efficacy.
Methods: Four groups of seven New Zealand rabbits were assigned to the following intrapleural treatment groups: 2 mL of 2% iodopovidone, 2 mL of 4% iodopovidone, 2 mL of 4% iodopovidone plus 0.8 mg/kg triamcinolone intramuscularly weekly and 10 mL/kg doxycycline in 2 mL. Pleural fluid was collected 24, 48 and 72 h after intrapleural injections and analysed for WCC, protein and LDH levels. The rabbits were killed 2 weeks after the injections. Pleurodesis was graded macroscopically on a scale from 1 to 8. The degree of microscopic pleural fibrosis and pleural inflammation was graded from the HE stain slides.
Results: The mean volume of pleural fluid as well as the mean total WCC was significantly lower in the steroid‐treated group than in the other groups. The degree of the resulting pleurodesis was similar in the 2% iodopovidone (7.00 ± 1.29), 4% iodopovidone (7.71 ± 0.76) and doxycycline (7.14 ± 0.90) groups (P > 0.05) whereas the pleurodesis score of the steroid group (3.71 ± 1.98) was significantly lower than all other groups (P < 0.05). The degree of microscopic pleural fibrosis and pleural inflammation was significantly lower in the steroid group than in the 2% iodopovidone or 4% iodopovidone group.
Conclusions: Both 2% and 4% iodopovidone can induce pleurodesis as efficaciously as doxycycline in rabbits. Systemic corticosteroids significantly decrease the efficacy of iodopovidone in producing pleurodesis.
This study used a rabbit model to compare the effectiveness of iodopovidone in causing pleurodesis with that of doxycycline and investigated the mechanism by which iodopovine acts. Iodopovidone produced effective pleurodesis via an inflammatory mechanism and corticosteroids significantly decreased its efficacy.
Background and objective: The diagnosis of the cause of pleural effusions caused by cardiovascular diseases such as congestive heart failure (CHF) and acute pulmonary embolism is sometimes ...difficult. The purpose of the present study was to evaluate the utility of pleural fluid levels of N‐terminal pro‐brain natriuretic peptide (NT‐proBNP) in differentiating pleural effusions due to CHF, pulmonary embolism and post‐coronary artery bypass graft (CABG) surgery.
Methods: The levels of pleural fluid NT‐proBNP were measured by ELISA in a total of 40 patients: 10 with CHF, 10 with pulmonary embolism, 10 post‐CABG and 10 with carcinoma.
Results: The median level of NT‐proBNP in the pleural fluid of patients with CHF was 5390 pg/mL (25th to 75th percentiles, 4566 to 8158 pg/mL), which was significantly higher than that in patients with post‐CABG effusions (424 pg/mL, 352 to 873), with pulmonary embolism (311 pg/mL, 212 to 1159), or with carcinoma (302 pg/mL, 208 to 626) (P < 0.001, CHF group vs all other groups). In receiver‐operating curve analysis, an NT‐proBNP level of ≥2220 pg/mL demonstrated a sensitivity of 100% and a specificity of 96.7% for the identification of CHF.
Conclusions: Measurement of the NT‐proBNP level in pleural fluid is accurate in diagnosing the etiology of the effusion as CHF. Pleural fluid levels above 2220 pg/mL are essentially diagnostic that the pleural effusion is due to CHF.
The intrapleural injection of transforming growth factor (TGF)-β2 produces pleurodesis in rabbits associated with large pleural effusions. This study investigated whether anti-vascular endothelial ...growth factor (VEGF) antibody has any effect on the fluid production or the pleurodesis induced by TGF-β2.
Three groups of seven New Zealand white rabbits were administered TGF-β2 5.0 μg intrapleurally. Two groups received anti-VEGF antibody (10 mg/kg and 25 mg/kg) IV 24 h before TGF-β2 injection, and the third group received no antibody. The rabbits were killed at 2 weeks, and the macroscopic pleurodesis score was determined. The degree of pleural angiogenesis was assessed by immunohistochemical staining for factor VIII.
The administration of anti-VEGF antibodies had no significant effect on the pleural fluid volume or the characteristics of the fluid. The mean pleurodesis score of the seven rabbits in the control group (7.71 ± 0.76) was significantly (p < 0.05) higher than that for seven rabbits in the low-dose treatment group (4.43 ± 2.37) and the seven rabbits in the high-dose treatment group (4.57 ± 2.36) ±. The percentage of pleural tissue demonstrating angiogenesis in the control group (4.87 ± 0.43%) was significantly (p < 0.05) higher than that for the low-dose (2.94 ± 0.68%) or high-dose (2.67 ± 0.64%) antibody groups. When all rabbits were considered, there was a highly significant correlation between the pleural vascular density scores and the pleurodesis scores (r = 0.84, p < 0.01).
VEGF and angiogenesis appear to play a pivotal role in the production of a pleurodesis.
The natural history of familial pulmonary arterial hypertension (PAH) typically involves mutations in and/or haploinsuffciency of BMPR2 (gene for bone morphogenetic protein receptor type 2) but with ...low penetrance (10%–15%), delayed onset (in the third or fourth decade), and a gender bias (two- to fourfold more prevalent in postpubertal women). Thus, investigators have sought an understanding of “second-hit” modalities that might affect BMPR2 anterograde trafficking and/or function. Indeed, vascular lung lesions in PAH have been reported to contain enlarged “vacuolated” endothelial and smooth muscle cells with dilated endoplasmic reticulum (ER) cisternae, increased ER structural protein reticulon 4 (also called Nogo-B), and enlarged and fragmented Golgi apparatus. We recently replicated this cellular phenotype in primary human pulmonary arterial endothelial cells and human pulmonary arterial smooth muscle cells in culture by acute knockdown of the estradiol 17β (E2)–responsive proteins signal transducer and activator of transcription 5a (STAT5a) and STAT5b using small interfering RNAs (siRNAs). We have now investigated whether functional haploinsufficiences of these molecules, alone or in combination with other modalities, might interfere with anterograde membrane trafficking using (a) the quantitative tsO45VSV-G-GFP trafficking assay and (b) assays for cell-surface localization of Flag-tagged BMPR2 molecules. The G glycoprotein of the vesicular stomatitis virus (VSV-G) trafficking assay was validated in EA.hy926 endothelial cells by showing that cells exposed to monocrotaline pyrrole displayed reduced anterograde trafficking. Thereafter, the combinatorial knockdowns of STAT5a, STAT5b, BMPR2, and/or endothelial nitric oxide synthase as well as exposure to E2 or 2-methoxyestradiol were observed to significantly inhibit VSV-G trafficking. These combinations also led to intracellular trapping of wild-type Flag-tagged BMPR2. Overexpression of the PAH disease–derived F14 and KDF mutants of BMPR2, which were trapped in the ER/Golgi, also inhibited VSV-G trafficking in trans. Moreover, probenecid, a chemical chaperone in clinical use today, partially restored cell-surface localization of the KDF but not the F14 mutant. These data identify several combinatorial modalities that inhibit VSV-G anterograde trafficking and cause mislocalization of BMPR2. These modalities merit consideration in defining aspects of the late-developing and gender-biased natural history of human PAH.
Aim: The present study investigates the role of NF-κB in Bmpr2-related pulmonary hypertension (PH) using a murine model of PH with inducible overexpression of a cytoplasmic tail Bmpr2 mutation. ...Methods and Results: Electrophoretic mobility shift assay for nuclear extracts in Bmpr2R899X mouse lung and immunohistochemistry for NF-κB p65 in human PAH lung demonstrate that NF-κB is activated in end-stage disease. Acute inflammation or expression of a constitutively active NF-κB elicits a strong suppression of the BMP pathway in mice inversely correlating to activation of NF-κB targets. However, Bmpr2 mutation does not result in NF-κB activation in early disease development as assessed by luciferase reporter mice. Moreover, Bmpr2 mutant mice in which NF-κB activation is genetically blocked develop PH indistinguishable from that without the block. Finally, delivery of a virus causing NF-κB activation strongly exacerbates development of PH in Bmpr2 mutant mice, associated with increased remodeling. Conclusion: NF-κB activation exacerbates, but is not required for Bmpr2-related PH. Pulmonary vascular-specific activation of NF-κB may be a “second hit” that drives penetrance in heritable PH.
Background: It has been suggested that talc and doxycycline might be acting through different pathways in creating pleurodesis. We hypothesized that combining doxycycline and talc in half the usual ...doses would be synergistic in inducing pleurodesis.
Methods: Thirty-two rabbits were equally allocated into four groups: group 1, half-dose combination (5 mg/kg of doxycycline and 200 mg/kg of talc slurry); group 2, quarter-dose combination (2.5 mg/kg of doxycycline and 100 mg/kg of talc slurry); group 3, half-dose doxycycline (5 mg/kg of doxycycline); and group 4, half-dose talc (100 mg/kg of talc slurry). The pleurodesis scores from historical groups that received a full dose of talc (400 mg/kg) or doxycycline (10 mg/kg) were also compared to those obtained in the current study. Pleural fluid lactate dehydrogenase and protein levels were measured 24 h after the injection. Pleurodesis was graded from 1 (none) to 8 (> 50% symphysis) by two observers blinded to treatment groups. All rabbits underwent an ultrasonic examination on each side of their chest for the evaluation of pleurodesis.
Results: The mean pleurodesis score in the half-dose combination group was significantly higher than that in the half-dose talc group, half-dose doxycycline group, and the historical full-dose talc group (p = 0.009, p = 0.01, and p < 0.05, respectively). The quarter-dose combination group also had a significantly higher mean pleurodesis score compared to the half-dose talc group (p = 0.013). The difference between the historical full-dose doxycycline and the half-dose combination or quarter-dose combination groups was not significant (p > 0.05). A significantly positive correlation existed between the pleurodesis score and the ultrasound scores (r= 0.876, p = 0.000000005).
Conclusions: This study demonstrates that the combination of half doses of talc and doxycycline is more effective than the half dose of either drug alone or the full dose of talc in producing pleurodesis in rabbits. In addition, ultrasound is an accurate imaging modality for the evaluation of pleurodesis, in that the absence of pleural gliding on ultrasound correlates well with the presence of a pleurodesis in rabbits.
To establish a murine model of pneumothorax-associated pleural eosinophilia and to examine the role of interleukin (IL)-5 and IL-13 in the pathogenesis of this reaction.
An animal study.
One hundred ...thirty-seven C57/Bl-6 mice were used in this study. Wild-type animals were injected intrapleurally with 0.4 mL of air and were killed at different time points (30 min to 7 days) after the injection. IL-5 knockout and IL-13 knockout animals were killed 24 h and 48 h after the injection. Pleural inflammation was assessed by pleural lavage (PL).
PL cells were significantly increased following the induction of pneumothorax. The peak number of neutrophils, observed at 12 h, was 900 times higher than the control. The peak number of eosinophils, observed at 48 h, was 700 times higher than the control. Lymphocytes and mononuclear cells increased threefold and fourfold, respectively. IL-5 knockout mice had significantly less PL eosinophils than that the wild-type or the IL-13 knockout mice at 24 h (150 ± 46/μL, 903 ± 244/μL, and 912 ± 168/μL, respectively; p = 0.013) and 48 h (181 ± 45/μL, 1,587 ± 212/μL, and 1,379 ± 364/μL, respectively; p = 0.003).
Pneumothorax induces an inflammatory reaction of the mouse pleura, mainly characterized by increased neutrophils and eosinophils. IL-5 but not IL-13 is required for pneumothorax-associated pleural eosinophilia.
Macrophage transcription is significantly altered by HIV-1 infection. HIV Tat, an immediate-early product of the viral lifecycle, interacts with host transcription factors to alter host gene ...expression. We have previously shown that Tat represses transcription from the mannose receptor (MR) and the bone morphogenetic protein receptor-2 (BMPR2) promoters. The current study shows that transcriptional repression of these receptors involves Tat interaction with cyclin T1. Assays using U937 human monocytic cells transiently expressing MR or BMPR2 promoter-luciferase constructs demonstrated equal repression by one- and two-exon Tat gene products. A mutant Tat expression vector encoding Tat protein lacking the cyclin T1 binding domain failed to inhibit MR and BMPR2 promoter activities. Over-expression of cyclin T1 in the presence of wild-type Tat resulted in recovered activity from both promoters. Finally, two inhibitors of cyclin-dependent kinase 9 (a dominant negative CDK9 and flavopiridol) repressed activity from the MR and BMPR2 promoters.
Intrapleural fibrin deposition and subsequent fibrosis characterize evolving empyema and contribute to the morbidity associated with this condition. Single-chain urokinase (scuPA) is proenzyme form ...of the urokinase plasminogen activator, which has recently been shown to effectively clear intrapleural loculation in tetracycline-induced pleurodesis in rabbits. The authors therefore hypothesized that scuPA could likewise improve intrapleural injury associated with empyema. The authors used a rabbit model of empyema induced by intrapleural administration of Pasturella multocida to test this hypothesis and determined the effects of intrapleural scuPA on pleural fluids indices of inflammation and intrapleural fibrosis. The authors found that intrapleural administration of scuPA was well tolerated, generated readily detectable fibrinolytic activity in the empyema fluids and did not induce intrapleural or systemic bleeding. Pleural fluid volume, intrapleural protein, and D-dimer concentrations were increased at 24 and 48 hours (P < .01, respectively) after induction of empyema. Intrapleural loculation did not occur in the scuPA- or vehicle control-treated animals and there was no significant change in the pleural empyema or thickening scores. These findings confirm that intrapleural scuPA generates fibrinolysis in empyema fluids but does not alter fibrotic repair at the pleural surface or the intensity of intrapleural inflammation in this empyema model.
Purpose: We investigated whether oral tetracyclines could produce an efficient and safe pleurodesis as does parenteral doxycycline, which is currently unavailable in many countries.
Methods: ...Parenteral doxycycline (10 mg/kg), oral tetracycline (35 mg/kg), or doxycycline (10 mg/kg) was injected intrapleurally through a right chest tube in rabbits. The oral forms were dissolved in saline solution and passed through a sterile membrane filter. When daily aspirated pleural fluid was < 5 mL/24 h, the chest tube was removed. Fluid WBC, lactate dehydrogenase (LDH), and protein levels were measured 24 h after the injection. After the death of the animals on day 14, pleurodesis was graded from 1 (none) to 8 (> 50% symphysis) by two observers blinded to treatment groups.
Results: The right pleurodesis score of the combined oral groups (median, 7.0; interquartile range IQR, 4.0; n = 26) did not differ significantly (p = 0.349) from that of the parenteral group (median, 7.5; IQR, 6.0; n = 10). Oral tetracycline (capsule or tablet, n = 6 in each group) and doxycycline (capsule or tablet, n = 7 in each group) were as effective as parenteral doxycycline in producing pleurodesis: tetracycline capsule (median, 7.50; IQR, 6.00); tetracycline tablet (median, 6.50; IQR, 6.00); doxycycline capsule (median, 4.00; IQR, 1.00); doxycycline tablet (median, 8.00; IQR, 5.00), and parenteral doxycycline (median, 7.50; IQR, 6.00) p = 0.235. The left pleurodesis scores were 1.00 in all 36 rabbits. Fluid total volume, WBC, LDH, and protein levels were comparable between each oral and parenteral group, excluding WBCs in the tetracycline tablet group (p = 0.047). The complications were nonfatal (right hemothorax: tetracycline capsule n = 3/tetracycline tablet n = 2, doxycycline tablet n = 2, parenteral doxycycline n = 2; left hemothorax: tetracycline capsule n = 1; ascites: parenteral doxycycline n = 1). There was no growth on all filtrate cultures. Oral forms cost less than parenteral doxycycline (<$1 vs $4.72 per rabbit). Filtering costs were $1.12 per rabbit.
Conclusion: Oral tetracycline or doxycycline is as effective and safe as parenteral doxycycline in producing pleurodesis in rabbits; thus, they may also be used in humans.
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