Intrapleural nano-immunotherapy promotes innate and adaptive immune responses to enhance anti-PD-L1 therapy for malignant pleural effusion.

Malignant pleural effusion (MPE) is indicative of terminal malignancy with a uniformly fatal prognosis. Often, two distinct compartments of tumour microenvironment, the effusion and disseminated pleural tumours, co-exist in the pleural cavity, presenting a major challenge for therapeutic interventions and drug delivery. Clinical evidence suggests that MPE comprises abundant tumour-associated myeloid cells with the tumour-promoting phenotype, impairing antitumour immunity. Here we developed a liposomal nanoparticle loaded with cyclic dinucleotide (LNP-CDN) for targeted activation of stimulators of interferon genes signalling in macrophages and dendritic cells and showed that, on intrapleural administration, they induce drastic changes in the transcriptional landscape in MPE, mitigating the immune cold MPE in both effusion and pleural tumours. Moreover, combination immunotherapy with blockade of programmed death ligand 1 potently reduced MPE volume and inhibited tumour growth not only in the pleural cavity but also in the lung parenchyma, conferring significantly prolonged survival of MPE-bearing mice. Furthermore, the LNP-CDN-induced immunological effects were also observed with clinical MPE samples, suggesting the potential of intrapleural LNP-CDN for clinical MPE immunotherapy.

Better effect of intrapleural perfusion with hyperthermic chemotherapy by video-assisted thoracoscopic surgery for malignant pleural effusion treatment compared to normothermic chemoperfusion of the pleural cavity.

OBJECTIVE: The aim of this study was to assess the efficacy and safety of intrapleural perfusion with hyperthermic chemotherapy (IPHC) in treating malignant pleural effusion (MPE) compared to normothermic chemoperfusion of the pleural cavity (NCPC), and to investigate the better treatment to control MPE. METHODS: Malignant pleural effusion patients were enrolled in the study and treated with NCPC or IPHC under video-assisted thoracoscopic surgery (VATS). The chest drainage duration, clinical characteristics, and recurrence time of pleural effusion of patients were collected for statistical analysis. The chi-squared test and the Fisher's exact test were applied to compare the distribution differences in categorical variables. Progression-free survival (PFS) was estimated by the Kaplan-Meier method and was compared by the log-rank test. The survival analysis was performed using the Cox proportional hazards method. RESULTS: A total of 37 MPE patients were enrolled in this study. Twenty-seven patients received NCPC and 10 patients received IPHC under VATS. Significant differences were found in pathological types (p = 0.011), chest drainage duration (p = 0.005), and remission rate (p = 0.009) between two different treatment groups. The chest drainage duration of IPHC under VATS was shorter than the NCPC group (t = 2.969, p = 0.005). The remission rate of MPE in IPHC group was better than the NCPC one (OR = 0.031, 95% CI: 0.002-0.507, p = 0.015). The result of the Kaplan-Meier method showed that IPHC group could significantly prolong the PFS of patients with MPE compared to NCPC group (log-rank p = 0.002). Univariate cox regression analysis showed that patients with MPE in the IPHC group presented significant longer PFS than the NCPC group (HR = 0.264, 95% CI: 0.098-0.713, p = 0.009). Multivariate cox regression analysis further verified this conclusion (HR = 0.268, 95% CI: 0.096-0.753, p = 0.012). CONCLUSION: Compared to the NCPC, the IPHC under VATS presents a better control effect on MPE, shorter tube placement time, and longer complete remission time. For this reason, we recommend IPHC under VATS as the first-line treatment for patients with MPE those who can tolerate minimally invasive surgery.

Novel therapies for malignant pleural effusion: Anti­angiogenic therapy and immunotherapy (Review).

Patients with a variety of malignancies can develop malignant pleural effusion (MPE). MPE can cause significant symptoms and result in a marked decrease in quality of life and a poor prognosis. MPE is primarily considered as an immune and vascular manifestation of pleural metastases. In the present review, the existing evidence supporting the applicability of anti­angiogenic therapy and immunotherapy for the treatment of MPE was summarized. Patients with MPE have benefited from anti­angiogenic agents, including bevacizumab and endostar; however, no relevant prospective phase III trial has, thus far, specifically analyzed the benefit of anti­angiogenic therapy in MPE. Immunotherapy for MPE may be sufficient to turn a dire clinical situation into a therapeutic advantage. Similar to anti­angiogenic therapy, more clinical data on the efficiency and safety of immunotherapy for controlling MPE are urgently required. The combined use of anti­angiogenic therapy and immunotherapy may be a promising strategy for MPE, which requires to be further understood.

Efecto «tienda de campaña»: una complicación no descrita del marcaje percutáneo de nódulos pulmonares con semillas de I-125 / "Pole-tent" Effect: an Unreported Complication of Percutaneous Marking of Lung Nodules with I-125 Seeds

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Cryptococcal empyema treated with tube thoracostomy and intrapleural fibrinolysis.

A 55-year old woman with a history of relapsed T-cell ALL presented with right pleuritic chest pain and decreased breath sounds over the right hemithorax. Imaging of the chest showed loculated effusions. Tube thoracostomy was performed with intrapleural application of alteplase and dornase alpha over a 3-day period. Repeat imaging demonstrated a marked decrease in the volume of the effusion. In most prior published cases of pleural cryptococcosis, surgical drainage was required in addition to prolonged antifungal agents. More than 50% of patients with cryptococcal infection have severe underlying disease or immunodeficiency state making them high risk for surgery. This is the first case to our knowledge of cryptococcal empyema successfully treated with tube thoracostomy and intrapleural fibrinolysis.

Differential mechanisms are required for phrenic long-term facilitation over the course of motor neuron loss following CTB-SAP intrapleural injections.

Selective elimination of respiratory motor neurons using intrapleural injections of cholera toxin B fragment conjugated to saporin (CTB-SAP) mimics motor neuron death and respiratory deficits observed in rat models of neuromuscular diseases. This CTB-SAP model allows us to study the impact of motor neuron death on the output of surviving phrenic motor neurons. After 7(d) days of CTB-SAP, phrenic long-term facilitation (pLTF, a form of respiratory plasticity) is enhanced, but returns towards control levels at 28d. However, the mechanism responsible for this difference in magnitude of pLTF is unknown. In naïve rats, pLTF predominately requires 5-HT2 receptors, the new synthesis of BDNF, and MEK/ERK signaling; however, pLTF can alternatively be induced via A2A receptors, the new synthesis of TrkB, and PI3K/Akt signaling. Since A2A receptor-dependent pLTF is enhanced in naïve rats, we suggest that 7d CTB-SAP treated rats utilize the alternative mechanism for pLTF. Here, we tested the hypothesis that pLTF following CTB-SAP is: 1) TrkB and PI3K/Akt, not BDNF and MEK/ERK, dependent at 7d; and 2) BDNF and MEK/ERK, not TrkB and PI3K/Akt, dependent at 28d. Adult Sprague Dawley male rats were anesthetized, paralyzed, ventilated, and were exposed to acute intermittent hypoxia (AIH; 3, 5 min bouts of 10.5% O2) following bilateral, intrapleural injections at 7d and 28d of: 1) CTB-SAP (25 µg), or 2) un-conjugated CTB and SAP (control). Intrathecal C4 delivery included either: 1) small interfering RNA that targeted BDNF or TrkB mRNA; 2) UO126 (MEK/ERK inhibitor); or 3) PI828 (PI3K/Akt inhibitor). Our data suggest that pLTF in 7d CTB-SAP treated rats is elicited primarily through TrkB and PI3K/Akt-dependent mechanisms, whereas BDNF and MEK/ERK-dependent mechanisms induce pLTF in 28d CTB-SAP treated rats. This project increases our understanding of respiratory plasticity and its implications for breathing following motor neuron death.

The Safety and Exploration of the Pharmacokinetics of Intrapleural Liposomal Curcumin.

BACKGROUND: Malignant pleural effusion (MPE) is the accumulation of fluid in the pleural cavity as a result of malignancies affecting the lung, pleura and mediastinal lymph nodes. Curcumin, a compound found in turmeric, has anti-cancer properties that could not only treat MPE accumulation but also reduce cancer burden. To our knowledge, direct administration of curcumin into the pleural cavity has never been reported, neither in animals nor in humans. PURPOSE: To explore the compartmental distribution, targeted pharmacokinetics and the safety profile of liposomal curcumin following intrapleural and intravenous administration. METHODS: Liposomal curcumin (16 mg/kg) was administered into Fischer 344 rats by either intrapleural injection or intravenous infusion. The concentration of curcumin in plasma and tissues (lung, liver and diaphragm) were measured using ultra-performance liquid chromatography-mass spectrometry (UPLC-MS). Blood and tissues were examined for pathological changes. RESULTS: No pleural or lung pathologies were observed following intrapleural liposomal curcumin administration. Total curcumin concentration peaked 1.5 hrs after the administration of intrapleural liposomal curcumin and red blood cell morphology appeared normal. A red blood cells abnormality (echinocytosis) was observed immediately and at 1.5 hrs after intravenous infusion of liposomal curcumin. CONCLUSION: These results indicate that liposomal curcumin is safe when administered directly into the pleural cavity and may represent a viable alternative to intravenous infusion in patients with pleural-based tumors.

Inflammation in the pleural cavity following injection of multi-walled carbon nanotubes is dependent on their characteristics and the presence of IL-1 genes.

Upon inhalation, multi-walled carbon nanotubes (MWCNTs) may reach the subpleura and pleural spaces, and induce pleural inflammation and/or mesothelioma in humans. However, the mechanisms of MWCNT-induced pathology after direct intrapleural injections are still only partly elucidated. In particular, a role of the proinflammatory interleukin-1 (IL-1) cytokines in pleural inflammation has so far not been published. We examined the MWCNT-induced pleural inflammation, gene expression abnormalities, and the modifying role of IL-1α and ß cytokines following intrapleural injection of two types of MWCNTs (CNT-1 and CNT-2) compared with crocidolite asbestos in IL-1 wild-type (WT) and IL-1α/ß KO (IL1-KO) mice. Histopathological examination of the pleura 28 days post-exposure revealed mesothelial cell hyperplasia, leukocyte infiltration, and fibrosis occurring in the CNT-1 (Mitsui-7)-exposed group. The pleura of these mice also showed the greatest changes in mRNA and miRNA expression levels, closely followed by CNT-2. In addition, the CNT-1-exposed group also presented the greatest infiltrations of leukocytes and proliferation of fibrous tissue. WT mice were more prone to development of sustained inflammation and fibrosis than IL1-KO mice. Prominent differences in genetic and epigenetic changes were also observed between the two genotypes. In conclusion, the fibrotic response to MWCNTs in the pleura depends on the particles' physico-chemical properties and on the presence or absence of the IL-1 genes. Furthermore, we found that CNT-1 was the most potent inducer of inflammatory responses, followed by CNT-2 and crocidolite asbestos.

Pharmacokinetic evaluation of intrapleural perfusion with hyperthermic chemotherapy using cisplatin in patients with malignant pleural effusion.

OBJECTIVES: Malignant pleural effusion (MPE) has a poor prognosis. Most patients are treated with tube thoracostomy and sclerotherapy, although its success rate is around 64%. We have investigated intrapleural perfusion with hyperthermic chemotherapy (IPHC) using cisplatin in a study with a pharmacokinetic evaluation. METHODS: Patients with MPE, performance status of 0-1, possibility of good lung expansion and Cr<1.2mg/dL were treated with IPHC. The circuit was filled with 2000mL of normal saline containing cisplatin at a dose of 80mg/m2. Under video-assisted thoracoscopic surgery, the thoracic cavity was filled and perfused at a speed of approximately 1L/min at a temperature of 43°C for 1h. Perfusion solution and plasma samples were periodically collected, and concentrations of protein-unbound (free) platinum, which was the active derivative of cisplatin, and total platinum were determined by flameless atomic absorption spectrometry. RESULTS: Twenty patients with MPE (8 lung cancers, 7 mesotheliomas, and 5 others) were enrolled in this study. Rate of free platinum concentration relative to total platinum concentration in perfusion solution after 1hr IPHC at 43°C was 61.1±12.9%. Area under curve (AUC) of free platinum in the pleural space was calculated to be 26.3µg/mLxh, resulting in complete control of pleural effusion for 3 months after IHPC in all cases (95% confidence interval: 83-100%). While, absorption rate of total platinum from the pleural space was 33.8±17.0% (27.4±13.6mg/m2), and the maximum concentration of total platinum in serum was low, 0.66±0.31µg/mL, resulting in controllable side effects; grade 1 renal toxicity: 6 patients, grade 1 emesis: 7 patients. CONCLUSIONS: IPHC with cisplatin showed favorable pharmacokinetic profiles for an optional treatment to control malignant pleural effusion.

Beneficial effect of Ageratum conyzoides Linn (Asteraceae) upon inflammatory response induced by carrageenan into the mice pleural cavity.

ETHNOPHARMACOLOGICAL RELEVANCE: Ageratum conyzoides Linn (Asteraceae), a tropical plant that is very common in West Africa and some parts of Asia and South America, has been used to treat inflammatory disorders. In Brazil, teas made from A. conyzoides L. are used as anti-inflammatory, analgesic and anti-diarrheic agents. Therefore, it is necessary to study the mechanism of anti-inflammatory action of A. conyzoides L. to support its medicinal use for treating inflammatory conditions. These studies will also support the development of effective pharmacological agents with potent anti-inflammatory properties. AIM OF THE STUDY: To evaluate the anti-inflammatory effects of the crude extract (CE), its derived fractions: ethanol (EtOH-F), hexane (HEX-F), ethyl acetate (EtOAc-F) and dichloromethane (DCM-F) and isolated compounds, such as 5'-methoxy nobiletin (MeONOB), 1,2-benzopyrone and eupalestin, which are obtained from the aerial parts of A. conyzoides L. MATERIALS AND METHODS: These evaluations were performed using an animal model of inflammation induced by carrageenan. The following inflammatory parameters were analysed: leukocyte influx, protein concentration of the exudate, myeloperoxidase (MPO), adenosine deaminase (ADA) and nitric oxide metabolites (NOx) concentrations, interleukin 10 (IL-10), interleukin 17A (IL-17A), interleukin 6 (IL-6), tumor necrosis factor (TNF), interferon gamma (IFN-γ) and phosphorylation of p65 subunit of NF-κB (p-p65 NF-κB), p38 mitogen-activated protein kinases (p-p38 MAPK) were also analysed. RESULTS: CE, its EtOH-F, HEX-F, EtOAc-F and DCM-F and the isolated compounds, including MeONOB, 1,2-benzopyrone and eupalestin, significantly reduced leukocyte influx, protein concentration of the exudate, MPO, ADA, and NOx concentrations (p<0.05). CE, EtOH-F and isolated compounds significantly reduced IL-17A, IL-6, TNF and IFN-γ levels (p<0.05). CE, EtOH-F and isolated compound 1,2-benzopyrone also increased IL-10 levels (p<0.05). Isolated compounds, MeONOB, 1,2-benzopyrone and eupalestin, reduced p-p65 NF-κB and p-p38 MAPK (p<0.01). CONCLUSIONS: This study demonstrates that A. conyzoides L. exerts its important anti-inflammatory properties by inhibiting leukocyte influx and protein concentration of the exudate, as well as reducing the levels of several pro-inflammatory mediators. The anti-inflammatory action of A. conyzoides L. may be because of the inhibition of p65 NF-κB and MAPK activation by the isolated compounds.

Chronic mesothelial reaction and toxicity of potassium octatitanate fibers in the pleural cavity in mice and F344 rats.

Fiber-shaped particles of potassium octatitanate (tradename TISMO; chemical formula K2 O·6TiO2 ), which are morphologically similar to asbestos particles, were shown to induce severe proliferative reactions in the pleural mesothelium in a previous experiment carried out over 21 weeks. The present study aims to determine whether these fibers induce malignant mesotheliomas in rodents, and to examine chronic toxicity induced. Additionally, we investigated the specific differences observable between the biological responses to the direct infusion of the fibers alone into the pleural cavity and those induced by the co-administration of the fibers with a known carcinogen. To detect the induction of malignant pleural mesotheliomas, two experiments were undertaken. In Experiment 1, four strains of mice, A/J, C3H, ICR, and C57BL, were examined for 52 weeks after experimental treatment with TISMO. In Experiment 2, the F344 rats were treated with TISMO alone, the lung carcinogen N-bis (2-hydroxypropyl) nitrosamine (DHPN) alone, both TISMO and DHPN, or left untreated and were then examined for 52 weeks. In this experiment, malignant lesion induction was expected in the co-administration group. TISMO fibers were observed in the alveoli, indicating penetration through the visceral pleura in mice and rats. The histopathological detection of TISMO fibers in the liver and kidneys of mice and rats indicated migration of the fibers out of the pleural cavity. Atypical mesothelial cells with severe pleural proliferation were observed, but malignant mesotheliomas were not detected. Among the rats, there were no observed malignant alterations in the mesothelium induced by DHPN-TISMO co-administration.

Clinical effects of thermotherapy in combination with intracavitary infusion of traditional Chinese medicine in the treatment of malignant pleural effusion.

Malignant fluid, a commonly seen tumor associated complication, mainly includes peritoneal effusion, malignant pleural effusion and pericardial effusion. It can produce huge negative influence on the quality of life of patients and even lead to death. Treatment of malignant effusion is one of the effective measures for improving life expectancy of patients. To evaluate the effect of thermotherapy in combination with intracavitary infusion of Kangai injection in treating malignant pleural effusion, 195 patients who received treatment from April 2010 to October 2014 in the First Affiliated Hospital of Zhengzhou University were selected and divided into an observation group and two control groups (group A and B). The observation group was treated by thermotherapy in combination with intracavitary infusion of kangai injection. Control group A was treated by intracavitary infusion of kangai injection and control group B was treated by hyperthermal perfusion in combination with intracavity chemotherapy. Clinical effects, quality of life, treatment safety and untoward reactions were compared between the groups. It was found that differences of WBC, RBC and PLT levels before and after treatment had no statistical significance comparisons within group and comparisons between groups (P>0.05); hepatic and renal functions of the groups had no remarkable difference before or after treatment (P>0.05). The clinical effect of the observation group was superior to that of control groups A and B (P less than 0.05); the Karnofsky performance status (KPS) score of the observation group was much higher than that of control groups A and B (79.34±10.58 vs 71.11±9.64), but the difference of the ZPS score between groups had no statistical significance (P>0.05). It can be concluded that thermotherapy in combination with intracavitary infusion of traditional Chinese medicine can be safely applied as it has positive effects and remarkably improves quality of life, therefore it is clinically worth promoting.

[Therapeutical effects of pleural injecting recombinant human endostain to 
malignant pleural effusion nude mice model].

BACKGROUND AND OBJECTIVE: The prognosis of malignant pleural effusion (MPE) was poor, injecting anti-angiogenesis agents in pleural cavity might be to reducing the volume of pleural effusion. The aim of this study is to investigate the therapeutical effect of pleural injection of recombinant human endostain, cisplatin and recombinant human endostain combined with cisplatin to MPE nude mice. METHODS: MPE model was built by intrpleural injection of Lewis lung cancer cells (LCC) into BALB/c nude mice. Intrpleural injection of recombinant human endostain (E), cisplatin (P) and recombinant human endostain combined with cisplatin (EP) was performed, MPE volume was measured, immunohistochemistry of CD31 was carried out to calculate micro vessel density (MVD), angiogenesis and apoptosis gene expression was detected. RESULTS: MPE volume was reduced by intrapleiral injection of recombinant human endostain and recombinant human endostain combined with cisplatin, MPE volume was positive correlated with MVD. Vescular epidermal growth factor-α (VEGF-α) expression reduced simultaneously with expression of hypoxia induced factor-1 (HIF1-α) elevated at the same time. CONCLUSIONS: MPE model could be made by intrapleural injection of LLC. Intrapleural injection of recombinant human endostain could reduce MPE volume of nude mice. The potential molecular mechanism of the therapeutical effects of intapleural injection of recombiant endostatin might be related to the downregulation of VEGF-α expression and neovascularization.
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Biodegradable drug-eluting pellets provide steady and sustainable cisplatin release in the intrapleural cavity: in vivo and in vitro studies.

The purpose of this study is to develop biodegradable drug-eluting pellets to provide a sustainable delivery of cisplatin intrapleurally. Poly(d,l)-lactide-co-glycolide (PLGA) (LA:GA=50:50) copolymer and cisplatin were mixed, compressed, and sintered to construct biodegradable pellets and placed in phosphate-buffered saline to test the characteristics of in vitro release. In vivo, equal amounts of cisplatin (10mg/kg) were introduced into rabbit pleural cavities either by free form (Gr1) or pellets form (Gr2). Cisplatin concentrations in the collected pleural effusion and blood were measured and compared by repeated measurement ANOVA. In vitro, approximately 5% of the cisplatin was released in the first day while the rest was gradually released in the following 50 days. In vivo, the cisplatin level in the pleural fluid was equally high during the first 2 days but dropped quickly in Gr1 while remaining high in Gr2 for 18 days, the difference was statistically significant (P<0.001) In contrast, the plasma cisplatin level was 10 times significantly higher in Gr1 than in Gr2 (P<0.001), which resulted in two early deaths of rabbits. Thus we concluded that our biodegradable pellets could achieve high and steady cisplatin release in the pleural cavity. This novel drug delivery system may have the potential to serve as an adjuvant treatment for malignant pleural lesion.

WGA-Alexa transsynaptic labeling in the phrenic motor system of adult rats: Intrapleural injection versus intradiaphragmatic injection.

BACKGROUND: Intrapleural injection of CTB-Alexa 488, a retrograde tracer, provides an alternative labeling technique to the surgically invasive laparotomy required for intradiaphragmatic injection. However, CTB-Alexa 488 is incapable of crossing synapses restricting the tracer to the phrenic nuclei and the intercostal motor nuclei in the spinal cord. NEW METHOD: Intrapleural injection of WGA-Alexa 488, a transsynaptic tracer, provides a method to label the respiratory motor pathway in both the spinal cord and medulla. Intradiaphragmatic injection of WGA-Alexa 594 and vagal nerve injections of True blue were used to confirm the phrenic nuclei and to differentiate between the rVRG and the NA in the medulla. RESULTS: Following intrapleural injection, WGA-Alexa 488 was retrogradely transported to the phrenic nuclei and to the intercostal motor nuclei. Subsequently WGA-Alexa 488 was transsynaptically transported from the phrenic motoneurons to the pre-motor neurons in the rVRG that provide the descending drive to the phrenic neurons during inspiration. In addition WGA-Alexa 488 was identified in select cells of the NA confirmed by a dual label of both WGA-Alexa 488 and True blue. COMPARISON WITH EXISTING METHOD: WGA-Alexa 488 demonstrates retrograde transsynaptic labeling following intrapleural injection whereas the previous method of injecting CTB-Alexa 488 only demonstrates retrograde labeling. CONCLUSIONS: Intrapleural injection of WGA-Alexa fluor conjugates is an effective method to transsynaptically label the phrenic motor system providing an alternative for the invasive laparotomy required for intradiaphragmatic injections. Furthermore, the study provides the first anatomical evidence of a direct synaptic relationship between rVRG and select NA cells.

Respiratory function after selective respiratory motor neuron death from intrapleural CTB-saporin injections.

Amyotrophic lateral sclerosis (ALS) causes progressive motor neuron degeneration, paralysis and death by ventilatory failure. In rodent ALS models: 1) breathing capacity is preserved until late in disease progression despite major respiratory motor neuron death, suggesting unknown forms of compensatory respiratory plasticity; and 2) spinal microglia become activated in association with motor neuron cell death. Here, we report a novel experimental model to study the impact of respiratory motor neuron death on compensatory responses without many complications attendant to spontaneous motor neuron disease. In specific, we used intrapleural injections of cholera toxin B fragment conjugated to saporin (CTB-SAP) to selectively kill motor neurons with access to the pleural space. Motor neuron survival, CD11b labeling (microglia), ventilatory capacity and phrenic motor output were assessed in rats 3-28days after intrapleural injections of: 1) CTB-SAP (25 and 50µg), or 2) unconjugated CTB and SAP (i.e. control; (CTB+SAP). CTB-SAP elicited dose-dependent phrenic and intercostal motor neuron death; 7days post-25µg CTB-SAP, motor neuron survival approximated that in end-stage ALS rats (phrenic: 36±7%; intercostal: 56±10% of controls; n=9; p<0.05). CTB-SAP caused minimal cell death in other brainstem or spinal cord regions. CTB-SAP: 1) increased CD11b fractional area in the phrenic motor nucleus, indicating microglial activation; 2) decreased breathing during maximal chemoreceptor stimulation; and 3) diminished phrenic motor output in anesthetized rats (7days post-25µg, CTB-SAP: 0.3±0.07V; CTB+SAP: 1.5±0.3; n=9; p<0.05). Intrapleural CTB-SAP represents a novel, inducible model of respiratory motor neuron death and provides an opportunity to study compensation for respiratory motor neuron loss.

Pleurodesis induction in rats by Copaiba (Copaifera multijuga Hayne) oil.

This study aims to assess and compare copaiba oleoresin of Copaifera multijuga and 0.5% silver nitrate for the induction of pleurodesis in an experimental model. Ninety-six male Wistar rats were divided into three groups: control (0.9% saline solution), copaiba (copaiba oil), and silver nitrate (0.5% silver nitrate). The substances were injected into the right pleural cavity and the alterations were observed macroscopically and microscopically at 24, 48, 72, and 504 h. The value of macroscopic alterations grade and acute inflammatory reaction grade means was higher in the 24 h copaiba group in relation to silver nitrate. Fibrosis and neovascularization means in the visceral pleura were higher in 504 h copaiba group in relation to the silver nitrate group. The grade of the alveolar edema mean was higher in the silver nitrate group in relation to the copaiba group, in which this alteration was not observed. The presence of bronchopneumonia was higher in the 24 h silver nitrate group (n = 4) in relation to the copaiba group (n = 0). In conclusion, both groups promoted pleurodesis, with better results in copaiba group and the silver nitrate group presented greater aggression to the pulmonary parenchyma.

Size- and shape-dependent pleural translocation, deposition, fibrogenesis, and mesothelial proliferation by multiwalled carbon nanotubes.

Multiwalled carbon nanotubes (MWCNT) have a fibrous structure similar to asbestos, raising concern that MWCNT exposure may lead to asbestos-like diseases. Previously we showed that MWCNT translocated from the lung alveoli into the pleural cavity and caused mesothelial proliferation and fibrosis in the visceral pleura. Multiwalled carbon nanotubes were not found in the parietal pleura, the initial site of development of asbestos-caused pleural diseases in humans, probably due to the short exposure period of the study. In the present study, we extended the exposure period to 24 weeks to determine whether the size and shape of MWCNT impact on deposition and lesion development in the pleura and lung. Two different MWCNTs were chosen for this study: a larger sized needle-like MWCNT (MWCNT-L; l = 8 µm, d = 150 nm), and a smaller sized MWCNT (MWCNT-S; l = 3 µm, d = 15 nm), which forms cotton candy-like aggregates. Both MWCNT-L and MWCNT-S suspensions were administered to the rat lung once every 2 weeks for 24 weeks by transtracheal intrapulmonary spraying. It was found that MWCNT-L, but not MWCNT-S, translocated into the pleural cavity, deposited in the parietal pleura, and induced fibrosis and patchy parietal mesothelial proliferation lesions. In addition, MWCNT-L induced stronger inflammatory reactions including increased inflammatory cell number and cytokine/chemokine levels in the pleural cavity lavage than MWCNT-S. In contrast, MWCNT-S induced stronger inflammation and higher 8-hydroxydeoxyguanosine level in the lung tissue than MWCNT-L. These results suggest that MWCNT-L has higher risk of causing asbestos-like pleural lesions relevant to mesothelioma development.

Lung toxicity assessment using bronchoalveolar lavage fluid and pleural lavage fluid cytology by intratracheal treatment in rats.

Usefulness of bronchoalveolar lavage fluid (BALF) and pleural cavity lavage fluid (PLF) as an experimental material was evaluated for the assessment of pulmonary toxicity of chemicals in rats. From the viewpoint of safety, isoflurane can be used for euthanasia/anesthesia because there was no difference in biological properties of BALF between diethyl ether and isoflurane. Here, we also recognized phosphate buffered saline (PBS) and distilled water equally as a solvent/vehicle for negative control. PLF is also provided as a useful target material as well as BALF for assessing chemical lung toxicity. To evaluate the method, we used zinc chloride as a model chemical and obtained the expected and satisfied results. We may conclude that the intratracheal treatment and combination usage of BALF and PLF as a target material is a good method for assessment of chemical pulmonary (lung and plural cavity) toxicity in rats.

Indicaxanthin from cactus pear fruit exerts anti-inflammatory effects in carrageenin-induced rat pleurisy.

Nutritional research has shifted recently from alleviating nutrient deficiencies to chronic disease prevention. We investigated the activity of indicaxanthin, a bioavailable phytochemical of the betalain class from the edible fruit of Opuntia ficus-indica (L. Miller) in a rat model of acute inflammation. Rat pleurisy was achieved by injection of 0.2 mL of λ-carrageenin in the pleural cavity, and rats were killed 4, 24, and 48 h later; exudates were collected to analyze inflammatory parameters, such as nitric oxide (NO), prostaglandin E(2) (PGE(2)), interleukin-1ß (IL-1ß), and tumor necrosis factor-α (TNF-α); cells recruited in pleura were analyzed for cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS) expression, and nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) activation. Indicaxanthin (0.5, 1, or 2 µmol/kg), given orally before carrageenin, time- and dose-dependently, reduced the exudate volume (up to 70%) and the number of leukocytes recruited in the pleural cavity (up to 95%) at 24 h. Pretreatment with indicaxanthin at 2 µmol/kg inhibited the carrageenin-induced release of PGE(2) (91.4%), NO (67.7%), IL-1ß (53.6%), and TNF-α (71.1%), and caused a decrease of IL-1ß (34.5%), TNF-α (81.6%), iNOS (75.2%), and COX2 (87.7%) mRNA, as well as iNOS (71.9%) and COX-2 (65.9%) protein expression, in the recruited leukocytes. Indicaxanthin inhibited time- and dose- dependently the activation of NF-κB, a key transcription factor in the whole inflammatory cascade. A pharmacokinetic study with a single 2 µmol/kg oral administration showed a maximum 0.22 ± 0.02 µmol/L (n = 15) plasma concentration of indicaxanthin, with a half-life of 1.15 ± 0.11 h. When considering the high bioavailability of indicaxanthin in humans, our findings suggest that this dietary pigment has the potential to improve health and prevent inflammation-based disorders.