Talc slurry pleurodesis. Pleural fluid and histologic analysis

Platelet-Rich Plasma for Pleurodesis: An Experimental Study in Rabbits

Background and Objectives: This study was designed to evaluate platelet-rich plasma (PRP) as a method of pleurodesis in a rabbit model. Pleurodesis with PRP was compared against the gold-standard use of talc. The secondary evaluation assessed the ideal time for achieving pleurodesis. Materials and Methods: 25 healthy New Zealand white rabbits were assigned to three groups, as follows: 12 animals in the first and second groups, as well as one animal with no intervention in the final group, which was used as a control. The talc pleurodesis group (baseline) underwent pleurodesis with sterile talc, which is the gold-standard sclerosing agent used for pleurodesis. The PRP group underwent pleurodesis using autologous PRP. The last group had one rabbit with no intervention. A total of 12 rabbits (n = 6 for the talc pleurodesis group and n = 6 for the PRP group) were sacrificed 3 days (72 h) after the intervention, and 12 rabbits (n = 6 for the talc pleurodesis group and n = 6 for the PRP group) were sacrificed 6 days (144 h) after the intervention. In both the talc and PRP group, FBC and CRP were measured before the intervention and in 3 or 6 days afterwards, respectively. The pleura and the lungs were evaluated histopathologically. Results: Macroscopically, there were no statistically significant differences between the two groups. In terms of microscopic findings, there were no statistically significant differences in inflammatory reactions provoked in the visceral and parietal pleura between the PRP and talc. In addition, with talc pleurodesis, a foreign-body reaction was observed in about 50% of the cases, which was not observed with PRP. In terms of inflammation between 3 and 6 days, there were no statistically significant differences with PRP, there was only a statistically significant difference between 3 and 6 days regarding the parietal pleura in the talc group. Conclusions: The instillation of autologous PRP in the pleural cavity shows promise in achieving pleurodesis. The efficacy of PRP as a pleurodesis agent should be examined further.

Evaluation of pleural lesions after pleurodesis with OK-432 by fluorodeoxyglucose-positron emission tomography/CT

OBJECTIVE

This study aimed to determine changes in FDG-PET/CT after pleurodesis with OK-432 and to investigate differences in the changes between non-malignant and malignant lesions.

METHODS

Study participants were 17 patients with a history of malignant chest disease who underwent FDG-PET/CT after pleurodesis using OK-432 and in whom pleural lesions were determined to be non-malignant (n = 8) or malignant (n = 9). FDG uptake (SUV_max) was counted on all pleural lesions. CT findings (CT attenuation, shape) of pleural lesions with increased FDG uptake were evaluated.

RESULTS

The number of patients with increased FDG uptake in the pleura differed significantly between the non-malignant group (3/8) and malignant group (9/9) (p < 0.01) The mean SUV_max of non-malignant lesions with increased FDG uptake was 2.3 ± 0.7 vs. 6.2 ± 2.2 in malignant lesions, for a significant difference (p < 0.01). The mean CT attenuation of lesions was 36 ± 11 HU in the non-malignant group and 34 ± 14 HU in the malignant group, a difference that was not significant (p = 0.91). There was a significant difference in nodular and linear shapes between non-malignant and malignant lesions (p < 0.01). All non-malignant lesions were linear.

CONCLUSIONS

Positive FDG uptake was shown in non-malignant pleural lesions as well as in malignant pleural lesions after pleurodesis using OK-432. Combined analysis of FDG accumulation and CT morphology is helpful to distinguish between benign and malignant lesions.

Clinically important associations of pleurodesis success in malignant pleural effusion: Analysis of the TIME1 data set

BACKGROUND AND OBJECTIVE

Chemical pleurodesis is performed for patients with MPE with a published success rate of around 80%. It has been postulated that inflammation is key in achieving successful pleural symphysis, as evidenced by higher amounts of pain or detected inflammatory response. Patients with mesothelioma are postulated to have a lower rate of successful pleurodesis due to lack of normal pleural tissue enabling an inflammatory response.

METHODS

The TIME1 trial data set, in which pleurodesis success and pain were co-primary outcome measures, was used to address a number of these assumptions. Pain score, systemic inflammatory parameters as a marker of pleural inflammation and cancer type were analysed in relation to pleurodesis success.

RESULTS

In total, 285 patients were included with an overall success rate of 81.4%. There was a significantly higher rise in CRP in the Pleurodesis Success group compared with the Pleurodesis Failure group (mean difference: 19.2, 95% CI of the difference: 6.2-32.0, P = 0.004) but no significant change in WCC. There was no significant difference in pain scores or analgesia requirements between the groups. Patients with mesothelioma had a lower rate of pleurodesis success than non-mesothelioma patients (73.3% vs 84.9%, χ² = 5.1, P = 0.023).

CONCLUSION

Change in CRP during pleurodesis is associated with successful pleurodesis but higher levels of pain are not associated. Patients with mesothelioma appear less likely to undergo successful pleurodesis than patients with other malignancies, but there is still a significant rise in systemic inflammatory markers. The mechanisms of these findings are unclear but warrant further investigation.

Experimental validation of talc pleurodesis for carcinomatous pleuritis in an animal model

OBJECTIVE

This study was performed to evaluate the change of pleural cavity by talc pleurodesis for carcinomatous pleuritis in an animal model.

METHODS

Models of malignant pleuritis were produced by an intra-venous injection of lung adenocarcinoma cells to male BALB/c nude mice at 6 weeks of age. Two weeks after the injection, either talc or saline was injected into the left thoracic cavity and the mice were further observed for 4 weeks. Six weeks after the injection, they were killed and the occurrence of lung cancer, amount of pleural effusion, and histological change of the pleural cavity were examined and compared between the two groups with or without talc administration.

RESULTS

Talc administration caused a significant reduction in pleural effusion with no increase of pleural adhesion. Talc administration resulted in marked pleural thickening compared to saline treatment. The vascular architecture and its area did not differ between the two groups.

CONCLUSION

Talc pleurodesis to reduce pleural effusion is valid for carcinomatous pleuritis, potentially through an acceleration of pleural thickening.

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.

Potential Pitfall in the Assessment of Lung Cancer with FDG-PET/CT: Talc Pleurodesis Causes Intrathoracic Nodal FDG Avidity

Objective. Talc pleurodesis is a common procedure performed to treat complications related to lung cancer. The purpose of our study was to characterize any thoracic nodal findings on FDG PET/CT associated with prior talc pleurodesis. Materials and Methods. The electronic medical record identified 44 patients who underwent PET/CT between January 2006 and December 2010 and had a history of talc pleurodesis. For each exam, we evaluated the distribution pattern, size, and attenuation of intrathoracic lymph nodes and the associated standardized uptake value. Results. High-attenuation intrathoracic lymph nodes were noted in 11 patients (25%), and all had corresponding increased FDG uptake (range 2–9 mm). Involved nodal groups were anterior peridiaphragmatic (100%), paracardiac (45%), internal mammary (25%), and peri-IVC (18%) nodal stations. Seven of the 11 patients (63%) had involvement of multiple lymph nodal groups. Mean longitudinal PET/CT and standalone CT followups of 15 ± 11 months showed persistence of both high-attenuation and increased uptake at these sites, without increase in nodal size suggesting metastatic disease involvement. Conclusions. FDG avid, high-attenuation lymph nodes along the lymphatic drainage pathway for parietal pleura are a relatively common finding following talc pleurodesis and should not be mistaken for nodal metastases during the evaluation of patients with history of lung cancer.

Effectiveness and safety of iodopovidone in an experimental pleurodesis model

OBJECTIVES

Chemical pleurodesis is an important therapeutic tool to control recurrent malignant pleural effusion. Among the various sclerosing agents, iodopovidone is considered effective and safe. However, in a recent study, ocular changes were described after iodopovidone was used in recurrent pneumothorax. The aim of the study was to evaluate the efficacy and morbidity of iodopovidone pleurodesis in an experimental model.

METHODS

New Zealand rabbits were submitted to intrapleural injection of iodopovidone at concentrations of 2%, 4% and 10%. Biochemical (lactic dehydrogenase, proteins, triiodothyronine, free thyroxine, urea and creatinine) and immunological (Interleukin-8 [IL-8], VEGF and TGFβ) parameters were measured in the pleural fluid and blood. After 1, 3, 7, 14 and 28 days, groups of animals were euthanized, and macro- (pleura) and microscopic (pleura and retina) analyses were performed.

RESULTS

An early pleural inflammatory response with low systemic repercussion was observed without corresponding changes in thyroid or renal function. The higher concentrations (4% and 10%) correlated with greater initial exudation, and maximum pleural thickening was observed after 28 days. No changes were observed in the retinal pigment epithelium of the rabbits.

CONCLUSION

Iodopovidone is considered to be an effective and safe sclerosing agent in this animal model. However, its efficacy, tolerance and safety in humans should be further evaluated.

Role of talc modulation on cytokine activation in cancer patients undergoing pleurodesis

We investigate the mechanism of talc pleurodesis (TP) in 20 patients with recurrent malignant pleural effusion and 10 patients with nonmalignant pleural effusions. We measured IL-8 levels before and 6 h after TP and find a significant threefold increase (2.26 ng/mL ± 0.7 to 6.5 ng/mL 0.1), which explains the recruitment of inflammatory cells in these patients. We hypothesize that TP is enable by stimulating the mesothelial cells (MS) to secrete FGF. A significant tenfold increase in FGF-b (0.05 ng/mL ± 0.02 to 0.44 ng/mL 0.6) was seen 24 h after talc instillation (P < 0.04). In order to examine whether FGF-b is secreted by MS cells, MS recovered from CHF patients with recurrent pleural effusions were cultured for 48 h in the presence or absence of increasing concentrations of talc (from 100 ng/mL to 1 mg/mL). They produced significant levels of FGF-b in a dose dependent manner (P < 0.005). We hypothesized that a successful pleurodesis involves an early enhanced recruitment of inflammatory cells through a rise of IL-8 followed by enrollment of fibroblasts from the submesothelial space through increased mesothelial FGF-b production.

Mechanisms of pleurodesis

Pleurodesis aims to obliterate the pleural space by producing extensive adhesion of the visceral and parietal pleura, in order to control relapse of either pleural effusions (mostly malignant) or pneumothorax. A tight and complete apposition between the two pleural layers is a necessary condition to obtain a successful pleurodesis, but--besides this mechanical aspect--there are many biological mechanisms that appear to be common to most of the sclerosing agents currently used. Following intrapleural application of the sclerosing agent, diffuse inflammation, pleural coagulation-fibrinolysis imbalance (favoring the formation of fibrin adhesions), recruitment and subsequent proliferation of fibroblasts, and collagen production are findings in the pleural space. The pleural mesothelial lining is the primary target for the sclerosant and plays a pivotal role in the whole pleurodesis process, including the release of several mediators like interleukin-8, transforming growth factor-β and basic fibroblast growth factor. When the tumor burden is high, normal mesothelial cells are scarce, and consequently the response to the sclerosing agent is decreased, leading to failure of pleurodesis. Also, the type of tumor in the pleural cavity may also affect the outcome of pleurodesis (diffuse malignant mesothelioma and metastatic lung carcinomas have a poorer response). There is general agreement that talc obtains the best results, and there are also preliminary experimental studies suggesting that it can induce apoptosis in tumor cells and inhibit angiogenesis, thus contributing to a better control of the malignant pleural effusion. There is concern about complications (possibly associated with talc but other agents as well) related to systemic inflammation and possible activation of the coagulation cascade. In order to prevent extrapleural talc dissemination, large-particle talc is recommended. Although it could--to some degree--interfere with the mechanisms leading to pleurodesis and a carefully balanced clinical decision has therefore to be made, prophylactic treatment with subcutaneous heparin is recommended during hospitalization (immediately before and after the pleurodesis procedure).

Intrapleural therapy

Numerous intrapleural therapies have been adopted to treat a vast array of pleural diseases. The first intrapleural therapies proposed focused on the use of fibrinolytics and DNase to promote fluid drainage in empyema. Numerous case series and five randomized controlled trials have been published to determine the outcomes of fibrinolytics in empyema treatment. In the largest randomized trial, the use of streptokinase had no reduction in mortality, decortication rates or hospital days compared with placebo in the treatment of empyema. Criticism over study design and patient selection may have potentially affected the outcomes in this study. The development of dyspnoea is common in the setting of malignant pleural effusions. Pleural fluid evacuation followed by pleurodesis is often attempted. Numerous sclerosing agents have been studied, with talc emerging as the most effective agent. Small particle size of talc should be avoided because of increased systemic absorption potentiating toxicity, such as acute lung injury. Over the past several years, the use of chronic indwelling pleural catheters have emerged as the preferred modality in the treating a symptomatic malignant pleural effusion. For patients with malignant-related lung entrapment, pleurodesis often fails due to the presence of visceral pleural restriction; however, chronic indwelling pleural catheters are effective in palliation of dyspnoea. Finally, the use of staphylococcal superantigens has been proposed as a therapeutic model for the treatment of non-small lung cancer. Intrapleural instillation of staphylococcal superantigens increased median survival by 5 months in patients with non-small cell lung cancer with a malignant pleural effusion.

An update in the management of malignant pleural effusion

Malignant pleural effusion (MPE) usually presents in the disseminated and advanced stage of malignancy. Dyspnea is the debilitating symptom which needs palliation in these patients. Various modalities are available in the management of MPE. Careful consideration of the patient's expected survival and quality of life is needed when deciding the optimum treatment modality in such patients. In this article, different modalities of the palliative management of MPE are discussed with an attempt to derive a treatment algorithm for the management of MPE.

Changes in the pleural cavity by pleurodesis using talc or OK-432: an experimental study

PURPOSE

To define the changes in the pleural cavity after pleurodesis induced by talc or OK-432.

METHODS

A total of 30 rats were divided into three groups: a normal saline group (control group, n = 10), a group administered 400 mg/kg talc (talc group, n = 10), and a group administered 0.3 KE/kg OK-432 (OK-432 group, n = 10). Pleural cavities were examined and scored on the 30th day after the intrapleural administration of each agent.

RESULTS

Both the talc group and OK-432 group showed significantly higher macroscopic or microscopic pleurodesis scores than the control group (P < 0.05). Upon microscopic evaluation, the pleurodesis scores in the talc group were significantly higher than those in the OK-432 group (P < 0.01).The majority of the pleural thickness was found on the visceral pleura, and the parietal pleura was very thin. The thickness of the visceral pleura in the talc group was significantly higher than that in the OK-432 group (P < 0.005). Pathologically, the pleural thickening in the talc group consisted of fibrous tissue with injury of the pleural mesothelium, and talc particles were seen in the submesothelial fibrotic tissue and inside the alveoli.

CONCLUSIONS

Talc pleurodesis induces more marked changes in the pleural cavity than OK-432-induced pleurodesis.

Comparison of side effects of oxytetracycline and talc pleurodesis: an experimental study

BACKGROUND

Chemical pleurodesis is widely recommended in the treatment of refractory pleural effusion or pulmonary air leak of different etiologies. Although several agents have been used, many questions have remained unanswered about their toxicity. Talc is the most commonly used agent for the treatment, with rare, serious complications reported. Oxytetracycline pleurodesis in clinical practice has been described in a few studies, but literature reveals no experimental studies using this agent. We performed a prospective, randomized, observer-blinded, controlled study to evaluate the changes in lung histology and systemic response to pleurodesis with oxytetracycline and talc in acute and subacute phases in a rat model.

METHODS

Forty-two male albino Wistar rats were divided into three groups and 3 subgroups with 7 animals in each. Group 1 was given oxytetracycline, 35 mg/kg; Group 2 was given talc slurry, 60 mg/kg in 0.5 mL saline solution, and Group 3 was given only 0.5 mL saline intrapleurally. In subgroups "a" the nimls were sacrificed at the postoperative 72nd hour and, in subgroups "b", on the postoperative day 7. The surfaces were graded by microscopic examination.

RESULTS

Oxytetracycline produced alveolar collapse, hemorrhage, edema, inflammation at the postoperative 72nd hour and hemorrhage on the postoperative day 7, while talc produced significant edema, inflammation, proliferation, fibrosis at the postoperative 72nd hour and hemorrhage, edema, inflammation, proliferation, and fibrosis on the postoperative day 7 (p < 0.0042). Talc produced significant edema compared to oxytetracycline on the postoperative day 7. On contralateral side, oxytetracycline and talc produced significant hemorrhage on the postoperative day 7 (p < 0.0042).

CONCLUSIONS

Both agents were shown to produce pulmonary lesions. In acute phase, the pulmonary side effects of oxytetracycline were more pronounced, whereas the side effects of talc were prolonged to subacute phase. We propose that the occasional side effects in humans may be related to these changes as were observed in our rat model, and like talc, oxytetracycline must be used cautiously in patients with limited respiratory function.

Iodopovidone is as effective as doxycycline in producing pleurodesis in rabbits

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.

Safety of pleurodesis with talc poudrage in malignant pleural effusion: a prospective cohort study

BACKGROUND

Talc is the most effective chemical pleurodesis agent for patients with malignant pleural effusion. However, concerns have arisen about the safety of intrapleural application of talc, after reports of development of acute respiratory distress syndrome in 1-9% of treated patients. Our aim was to establish whether use of large-particle-size talc is safe in patients with malignant pleural effusion.

METHODS

We did a multicentre, open-label, prospective cohort study of 558 patients with malignant pleural effusion who underwent thoracoscopy and talc poudrage with 4 g of calibrated French large-particle talc in 13 European hospitals, and one in South Africa. The primary endpoint was the occurrence of acute respiratory distress syndrome after talc pleurodesis.

FINDINGS

No patients developed acute respiratory distress syndrome (frequency 0%, one-sided 95% CI 0-0.54%). 11 (2%) patients died within 30 days. Additionally, seven patients had non-fatal post-thoracoscopy complications (1.2%), including one case of respiratory failure due to unexplained bilateral pneumothorax.

INTERPRETATION

Use of large-particle talc for pleurodesis in malignant pleural effusion is safe, and not associated with the development of acute respiratory distress syndrome.

CT appearances of talc pleurodesis

AIM

To report the computed tomography (CT) appearances of talc pleurodesis in the management of patients with pleural effusions and spontaneous pneumothorax.

MATERIALS AND METHODS

The post-pleurodesis CT studies of 16 patients obtained over a 5-year period were reviewed. The mean age was 63 years (range 41-79 years). Ten patients were male. After pleurodesis, nine patients underwent a single chest CT examination and seven patients underwent more than one.

RESULTS

The characteristic finding observed in all patients, except one, was the presence of high-density deposits in the posterior basal regions of the pleural space. These were typically linear in seven patients, nodular in two, and a combination of linear and nodular in six. In five patients talc deposits were present on both the visceral and parietal pleura separated by an effusion (a variant of the split pleura sign). Talc deposits extended into an interlobar fissure with associated fissural thickening in five patients. In patients who underwent more than one CT study, the appearances remained stable.

CONCLUSIONS

The typical finding was the presence of high attenuation areas in the posterior basal regions of the pleural space. Two new appearances were observed: extension of talc deposits into the fissure and the presence of a variant of the split pleura sign. It is important to recognize these CT appearances so as not to confuse them with other conditions such as asbestos exposure.

Growth factors in pleural fibrosis

PURPOSE OF REVIEW

Pleural fibrosis is a double-edged sword in clinical settings. Successful induction of pleural fibrosis is the basis of therapeutic pleurodesis. On the other hand, pleural septations and fibrosis are undesirable outcomes in pleural infection and fibrothoraces. The significance of growth factors in the pathogenesis of pleural fibrosis has become increasingly apparent.

RECENT FINDINGS

Recent findings have indicated that transforming growth factor beta is a key mediator of pleural fibrosis and demonstrated the therapeutic potential of both transforming growth factor beta itself and transforming growth factor beta inhibitors. Basic fibroblast growth factor has been highlighted as a key factor in successful pleurodesis, and in the formation of pleural effusions. Vascular endothelial growth factor inhibition has been shown to decrease pleural fibrosis in vivo. By contrast, hepatocyte growth factor stimulates non-fibrotic healing, while inhibition increases fibrosis.

SUMMARY

The actions of the growth factors, and their inhibitors, are potentially and/or currently applicable in a clinical setting. Understanding the biology of these growth factors may allow therapeutic manipulation of these cytokines to create pleurodesis or to inhibit pleural (and peritoneal) adhesion/fibrosis.

Predictors of acute lung injury and severe hypoxemia in patients undergoing operative talc pleurodesis

BACKGROUND

Acute lung injury (ALI) is a life-threatening complication of talc pleurodesis. This study defines characteristics that predispose patients to ALI and severe hypoxemia in patients after video-assisted thoracoscopic surgery (VATS) talc pleurodesis.

METHODS

Charts of patients who underwent talc pleurodesis at Northwestern Memorial Hospital between January 1, 1997 and December 31, 2003 were retrospectively reviewed. We sought variables associated with the development of postoperative ALI or severe hypoxemia, defined as an increase in fraction of the inspired oxygen by more than 0.15 within 24 hours after the surgery. The analysis included 84 patients (58 women, 26 men) who underwent VATS talc pleurodesis for malignant (n = 74) or benign (n = 10) indications.

RESULTS

ALI developed in 5 patients (5.9%), severe hypoxemia developed in 25 (29.8%), and 54 (64.3%) did not have postoperative complications. In multivariate analysis, the presence of peripheral edema before pleurodesis (p = 0.005), any preoperative requirement for supplemental oxygen (p = 0.032), and chemotherapy within 14 days before pleurodesis (p = 0.04) were identified as predictors of ALI or severe postoperative hypoxemia.

CONCLUSIONS

Oxygen supplementation, recent chemotherapy, and presence of peripheral edema were independent predictors of a combined outcome of ALI or severe hypoxemia after VATS talc pleurodesis. Patients with these characteristics might be at risk for adverse outcomes of talc pleurodesis and should be considered for alternative therapy for their effusions.

Combination therapy with intrapleural doxycycline and talc in reduced doses is effective in producing pleurodesis in rabbits

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.

Oral forms of tetracycline and doxycycline are effective in producing pleurodesis

PURPOSES

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 US dollar vs 4.72 US dollars per rabbit). Filtering costs were 1.12 US dollars 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.

Estudo das alterações ultra-estruturais em pleura de ratos pós pleurodese por talco

OBJETIVO: O talco é considerado um agente efetivo de pleurodese freqüentemente utilizado no tratamento de derrame pleural maligno. Entretanto, questiona-se sua segurança em relação à carcinogênese. O objetivo deste trabalho é descrever as alterações ultra-estruturais encontradas nas pleuras de ratos submetidos à pleurodese com talco buscando esclarecer sua segurança em relação à carcinogênese. MÉTODO: Neste estudo randomizado foram utilizados seis ratos machos do tipo Wistar, pesando 250 g. Através de uma toracotomia mínima no quinto espaço intercostal esquerdo foi colocado lavado de talco em concentrações de 0,5mg (n=2) e 0,1 mg (n=2) de talco por grama de peso. Dois ratos foram apenas anestesiados e foi instilado solução fisiológica (NaCl 0,9%) intrapleural para configurar o grupo controle. Os ratos foram mortos após 45 dias. As alterações morfológicas e morfométricas ultra-estruturais foram analisadas através de microscopia eletrônica de transmissão. RESULTADOS: A análise ultra-estrutural das pleuras submetidas à talcagem demonstrou desorganização celular do tecido conjuntivo, evidenciando alterações nucleares, mitocondriais e espessamento da camada submesotelial. O grupo controle manteve a arquitetura celular preservada. CONCLUSÕES: Este estudo revelou alterações da estrutura celular da pleura exposta ao talco quando comparado ao grupo controle.

Intrapleural Staphylococcal Superantigen Induces Resolution of Malignant Pleural Effusions and a Survival Benefit in Non-Small Cell Lung Cancer

BACKGROUND

Malignant pleural effusion (MPE) may occur in up to 50% of patients with non-small cell lung cancer (NSCLC). The majority of these patients have a poor performance status and a dismal prognosis, with survival duration ranging from 2 to 3 months. Since these patients are typically symptomatic from their MPE, prompt treatment is required. Patients with symptomatic MPE from NSCLC and poor performance scores (Eastern Cooperative Oncology Group [ECOG] score >/= 2, Karnofsky performance status [KPS] score < 50) are generally not offered systemic chemotherapy. Treatment is palliative and includes intrapleural catheter drainage or chemical pleurodesis with talc, doxycycline, or bleomycin. None of the latter modalities prolong survival.

OBJECTIVE

Our goal was to investigate the toxicity and therapeutic effect of a new therapeutic agent, Staphylococcus aureus superantigen (SSAg), a powerful T-cell stimulant administered intrapleurally to unselected, consecutive patients with MPE from NSCLC (stage IIIb with pleural effusion) and a poor performance status. By providing direct access of the SSAg to the bronchial and mediastinal lymphatics, we predicted that intrapleural administration of SSAg would induce resolution of MPE and prolong survival in this population with advanced NSCLC and a limited prognosis.

METHODS

Fourteen consecutive, unselected patients with MPE from NSCLC and a median pretreatment KPS score of 40 (range, 10 to 60) received pleural instillation of SSAg, 100 to 400 pg, once or twice weekly (mean, 3.7 +/- 1.3 treatments [+/- SD]) until the pleural effusions resolved. They were evaluated for drug toxicity, resolution, duration of MPE, and survival.

RESULTS

Other than mild fever (maximum grade 2), toxicity of SSAg treatment was trivial and notably devoid of respiratory distress or hypotension. Eleven patients had a complete response (CR), and 3 patients had a partial response of their MPE. In 12 patients, the response endured for > 90 days, with a median time to recurrence of 5 months (range, 3 to 23 months). The median survival for the SSAg-treated group was 7.9 months (range, 2 to 36 months; 95% confidence interval [CI], 5.9 to 11.4 months), compared to a median survival of 2.5 months (range, 0.1 to 57 months; 95% CI, 1.3 to 3.4 months) for 18 consecutive, unselected patients with MPE from NSCLC (stage IIIb) treated with talc poudrage (p = 0.044). Survival duration of all 14 SSAg-treated cases and 13 talc-poudrage-treated patients with comparable pretreatment KPS (range, 10 to 60; median, 40 and 30, respectively), and distribution (p = 0.5) was 7.9 months (95% CI, 5.9 to 11.4 months) and 2.0 months (95% CI, 0.4 to 2.9 months), respectively (p = 0.0023). Nine of 14 patients treated with SSAg survived > 6 months, 4 patients survived > 9 months, and 3 patients survived > 350 days. One of the patients in the CR group has survived 36 months. None of the 13 talc-treated patients survived > 6 months.

INTERPRETATION

In 14 unselected, consecutive patients with MPE from NSCLC and poor pretreatment performance (median KPS of 40), the intrapleural administration of SSAg was efficacious in resolving the MPE without any clinically important adverse effects. SSAg-treated patients with a median KPS of 40 (range, 10 to 60) had a median survival that exceeded that with talc poudrage, and was comparable to current systemic chemotherapy used in patients with KPS >/= 70 status. SSAg treatment is simple to perform, minimally invasive, and does not require hospital time. It may be an attractive alternative to existing palliative modalities for stage IIIb patients with MPE and poor performance who are not candidates for systemic chemotherapy.

Talc Pleurodesis

STUDY OBJECTIVES

Patients with recurrent pleural effusions secondary to malignancy are subjected to pleurodesis if clinically indicated. Pleurodesis involves the introduction of a sclerosing agent into the pleural space. Talc is one of the most commonly used sclerosing agents in treating patients with recurrent, symptomatic malignant pleural effusions. However, the mechanisms whereby talc mediates pleural fibrosis remain unclear. We hypothesized that the intrapleural instillation of talc induces the pleural mesothelial production of basic fibroblast growth factor (bFGF), which is responsible for pleural fibrosis.

METHODS

Samples of pleural fluid collected from 23 patients with malignant pleural effusions and 6 patients with congestive heart failure (control group) were included in this study. A tumor grading scale (1 to 9) was used to demonstrate the extent of the tumor. In vitro pleural mesothelial cells (PMCs) were activated with talc, and the conditioned medium was collected to evaluate bFGF levels by enzyme-linked immunosorbent assay. The bFGF-induced proliferation of fibroblasts was studied by [(3)H]thymidine incorporation. The messenger RNA expression of bFGF in talc-activated PMCs was determined by Northern analysis.

RESULTS

In this study, we demonstrated that patients who have undergone successful pleurodesis following intrapleural talc insufflation have significantly higher levels of bFGF in their pleural fluid compared to those who do not respond to pleurodesis. In addition, we found a significant negative correlation between bFGF levels and tumor size. Talc-activated PMCs produce significantly higher levels of bFGF compared to control, which correlates with bFGF messenger RNA expression in PMCs stimulated with talc. The neutralization of pleural fluids and conditioned medium from talc-stimulated PMCs with bFGF antibodies significantly inhibits the bFGF-induced proliferation of pleural fibroblasts.

CONCLUSIONS

An important outcome of this study was the finding that patients with extensive tumor involvement of the pleural mesothelium have a significantly lower pleural fluid bFGF response to talc compared to those who have limited involvement. Patients with limited pleural disease and higher bFGF responses go on to have successful pleurodesis, demonstrating that the presence of a mesothelium that is free of tumor enhances the possibility of success. In vitro PMCs stimulated with talc release biologically active bFGF.

Application cutanée de talc et sarcoïdose

INTRODUCTION

We report on two patients with sarcoidosis with disseminated nodes, who used talc on irritated cutaneous areas.

CASE REPORT

A histologic examination with intense polarised light showed up cristalline bi-refringent particles within vessels in contact with granulomatous areas. Microdissection followed by an electronic microscopy study and microanalysis was realised. In situ microanalysis allowed us to identify bi-refringent particles with a size of roughly 0.25microm as silica or silicate coming possibly from talc. We consequently studied a brand name talc. The diffraction spectrum showed that this product not only contained talc but also chlorite and quartz. Electron microscopy examination showed particles of all sizes even smaller than 0.25microm. These infra-microscopic particles, visible in a vessel only when agglomerated, could be invisible under optic microscopy (resolution: roughly 0.5microm) inside the granuloma even though they are responsible for it. Moreover, at this level of size of particles, they may escape mineralogic analyses which use methods involving the destruction of organic material, the mineral residue collecting on cellulose filter with a diameter generally of 0.45microm.

CONCLUSION

Two recent epidemiologic studies confirm the possible role of mineral exposure in sarcoidosis. Some sarcoidosis could be caused by mineral overload on genetically predisposed patients. Some cases could be related to mineral powder application. Among different types of mineral exposure, applications of cosmetic products may induce disseminated granulomatous reaction on genetically predisposed patients. Such applications have to be considered in epidemiologic studies.

Randomized trials describing lung inflammation after pleurodesis with talc of varying particle size

We report two trials describing whether talc pleurodesis with a mean particle size of less than 15 microm ("mixed" talc) produces more lung and systemic inflammation than tetracycline or "graded" talc (most particles < 10 microm were removed). First, 20 patients with malignant effusions received tetracycline or mixed talc. Changes in lung and systemic inflammation from lung clearance scans, oxygen saturations, and C-reactive protein from baseline to 48 hours after pleurodesis were recorded. Lung inflammation (change in isotope clearance, talc -9.26, SD 14.3 vs. tetracycline 4.10, SD 13.8 minutes; difference = -13.4; 95% confidence interval [CI], -26.6 to -0.2; p = 0.05) and systemic inflammation (change in C-reactive protein, talc 198 SD 79.2 vs. tetracycline 74 SD 79.4 microg/L; difference = 124; 95% CI, 50 to 199; p = 0.004) were greater after talc. Second, 48 patients received mixed or graded talc, and gas exchange was assessed from changes in the alveolar-arterial oxygen gradient. Mixed talc worsened gas exchange (oxygen gradient change, mixed 2.17 SD 1.74 kPa, 16.3 13.1 mm Hg vs. graded 0.72 SD 2.46 kPa 5.4 18.5 mm Hg, difference = 1.45; 95% CI, 0.2 to 2.7; p = 0.03) and induced more systemic inflammation than graded talc. We conclude that the routine use of graded talc for pleurodesis would reduce the morbidity of this procedure.

Chronic pain due to talc pleurodesis for spontaneous pneumothorax

Spontaneous pneumothorax is a common condition that usually affects young adults. Talc insufflation, either as a poudrage or by using slurry, is recognized as an effective treatment. We report a case of talc that resulted in chronic debilitating pain and necessitated further surgery.

Arterial Desaturation Syndrome Following Pleurodesis with Talc Slurry: Incidence, Clinical Features, and Outcome

The objectives were to define the incidence, risk factors, clinical features and outcome of arterial desaturation syndrome following talc pleurodesis in patients with malignant pleural effusions. This retrospective, observational study took place at a tertiary care cancer center in New York. All patients were those with malignancy who underwent pleurodesis with talc in 1998 at Memorial Sloan Kettering Cancer Center. Characteristics of patients are described by using summary statistics. Differences between groups were assessed with the Fisher's exact statistic for categorical variables and Student's t-test for continuous variables. Among patients who were considered to have arterial desaturation syndrome, we evaluated the relation of SaO2/FIO2 pre- and post-talc installation using a paired Student's t-test. During 1998, 120 patients underwent pleurodesis with talc, and 8 (7%) developed arterial desaturation following the procedure. Symptoms included chest pain, dyspnea, fever, and increased need for oxygen supplementation developed typically within 1 day. Three of the eight patients in this series required mechanical ventilation, but all recovered uneventfully after treatment, which included high-dose corticosteroids. Patients with breast and ovarian cancer appeared to be at increased risk for this complication compared to those patients with other types of cancer (p = 0.01). Approximately 7% of patients who have undergone sclerosis with talc for a malignant pleural effusion will develop arterial desaturation with clinically significant hypoxia requiring supplemental oxygen following the procedure. It appears that most patients recover from this complication and that those with breast and ovarian cancer may be at higher risk.

Influence of talc dose on extrapleural talc dissemination after talc pleurodesis

This study was designed to ascertain, in a rabbit model, extrapleural talc deposition and the related inflammatory response after talc slurry pleurodesis with two clinical doses, 200 and 50 mg/kg. Histopathologic evaluations revealed that whereas numerous rabbits receiving a high dose had talc in the ipsilateral (70%) and contralateral (55%) lung, mediastinum (90%), pericardium (30%), and liver (25%), a small number of animals treated with a low dose showed talc in the ipsilateral lung (10%) and mediastinum (20%) and none in the contralateral lung, pericardium, or liver. Hematologic and immunocytochemical analyses showed that a systemic inflammatory response develops shortly after pleurodesis with a high talc dose involving massive accumulation of neutrophils and macrophages in lung tissue. Zymography also revealed that the pulmonary expression of matrix metalloproteinases 2 and 9 was up-regulated in both lungs in a dose-dependent manner soon after talc instillation. Furthermore, microscopic examination of lung specimens revealed that the higher the dose of talc, the greater the development of both fibrotic visceral pleural thickening and foreign-body granulomas. These findings show pleurodesis with a high talc dose to be associated with an increased risk of extrapleural talc deposition, which may originate undesirable acute and chronic inflammatory responses.

Lung damage in experimental pleurodesis induced by silver nitrate or talc: 1-year follow-up

STUDY OBJECTIVE

To compare the lung damage caused by intrapleural silver nitrate (SN) with that caused by talc over a 12-month period.

DESIGN

One hundred forty rabbits received an intrapleural injection of 0.5% SN or 400 mg/kg talc slurry in 2 mL saline solution. Groups of 10 rabbits were killed after 1, 2, 4, 6, 8, 10, or 12 months. The macroscopic pleurodesis, microscopic lung changes (ie, collapse, hemorrhage, and edema), and cellular infiltrates (number and proportion of cells) were graded on a scale of 0 to 4.

RESULTS

The mean (+/- SEM) adhesion score after SN injection (3.3 +/- 0.1) was higher (p < 0.001) than that after talc injection (2.3 +/- 0.1). The mean alveolar collapse score was greater (p < 0.001) 1 month after SN injection (2.2 +/- 0.3) than after talc injection (0.2 +/- 0.1) and was similar from the second month on. The degree of parenchymal hemorrhage, by alveolar collapse score, (SN injection, 0.2 +/- 0.1; talc injection, 0.2 +/- 0.0) and edema (SN injection, 0.4 +/- 0.1; talc injection, 0.3 +/- 0.1) was minimal in both groups (p > 0.05). One month after the injection, the total number of inflammatory cells was greater (p < 0.001) in rabbits that had received SN injections (2.7 +/- 0.3) than in those that had received talc injections (1.2 +/- 0.1). From the second month on, cellularity decreased and became similar in both groups. The cellular profile was different, with a predominantly neutrophilic reaction after talc injection and a predominantly eosinophilic reaction after SN injection.

CONCLUSIONS

Rabbits injected with intrapleural 0.5% SN had significantly higher scores for adhesions than did those that had received talc injections, with mild and reversible alveolar collapse and an eosinophilic responses, conditions showing a clear tendency to normalize with time.

Distribution of calibrated talc after intrapleural administration: an experimental study in rats

STUDY OBJECTIVE

Many reports have shown that talc is the most effective and least expensive agent for the creation of a pleural symphysis. However, its use still remains controversial due to severe acute respiratory side effects possibly related to the systemic dissemination of talc particles. The purpose of this study was to assess the distribution of calibrated talc after intrapleural administration in rats. MATERIAL AMD METHODS: Thirty-seven Wistar male rats were randomly assigned to undergo pleurodesis by talc slurry (33 rats) or by simple chest tube drainage (control group; 4 rats). Forty milligrams of calibrated talc suspended in 1 mL sterile saline solution was injected into rats in the treated group. The animals were randomly assigned for autopsy at 24 or 72 h after pleural injection. Lungs, parietal pleura, diaphragm, liver, kidneys, spleen, pericardium, brain, and blood were assessed by polarized light for birefringent talc particle detection and counting.

RESULTS

No deaths were observed. The autopsies showed no pleurodesis at 24 and 72 h. Despite high doses of talc (extrapolated from the dose of 10 g in a 70-kg adult man), few talc particles were found in the liver of two rats, in the spleen of one rat, and only one particle of talc was observed at the brain surface of the rat studied by scanning electron microscopy. No particles were found in the other organs, in particular in the contralateral lung and blood, contrasting with previously published results using noncalibrated talc particles.

CONCLUSIONS

The lack of systemic dispersion of talc particles, with the packaging talc we currently use in our clinical practice, is probably due to the size of the talc particles, which are larger than the other talc preparations. Calibrated talc is required in case of intrapleural administration for pleurodesis to avoid systemic dissemination and potential secondary acute respiratory failures.

Influence of particle size on extrapleural talc dissemination after talc slurry pleurodesis

BACKGROUND

Cases of acute respiratory failure reported after talc pleurodesis have raised concerns about its safety. It has been speculated that this pulmonary inflammatory syndrome is secondary to the extrapleural dissemination of the talc particles.

STUDY OBJECTIVES

To test the hypothesis that particle size influences extrapleural talc deposition and pleural inflammation after talc slurry pleurodesis.

DESIGN

Thirty rabbits underwent pleurodesis as follows: 10 rabbits received 200 mg/kg of the talc used for human pleurodesis, normal talc (NT); 10 rabbits received 200 mg/kg of talc with particles of larger size, large talc (LT); and 10 rabbits received saline solution. Samples from the ipsilateral lung, chest wall, diaphragm, mediastinal pleura, heart, liver, spleen, and right kidney were obtained at 24 h and 7 days and processed for optic and electron microscopy and energy-dispersive x-ray analysis.

RESULTS

Visceral pleural thickening was greater with NT than with LT, but no differences were observed in the macroscopic score of adhesions. There was more talc in the lungs of the rabbits that received NT than in those that received LT. Talc particles were detected in mediastinum (100%) and pericardium (20%), irrespective of the talc used. Three animals, all receiving NT, had talc particles in the liver.

CONCLUSIONS

Our study shows that while both talcs were equally effective in achieving pleurodesis, the intrapleural injection of NT elicits greater pulmonary and systemic talc particle deposition than LT. Moreover, pleural inflammation was greater with NT than with LT.

Comparing transforming growth factor-beta2, talc and bleomycin as pleurodesing agents in sheep

BACKGROUND

Transforming growth factor (TGF)-beta2 can produce effective pleurodesis in animals, but its efficacy has not been compared with commonly used pleurodesing agents in sheep, which have a thick pleura resembling that of humans. The acute physiological effects and the level of systemic TGF-beta absorption after its intrapleural administration have not been studied. The aims of the present study were to compare: (i) the effectiveness of TGF-beta2, talc and bleomycin in producing pleurodesis in sheep; (ii) the acute side-effects and systemic TGF-beta levels following the intrapleural administration of these agents; and (iii) histological changes after intrapleural injections of these agents.

METHODOLOGY

Twelve sheep were divided into three groups and were given a single intrapleural dose of TGF-beta2 (0.25 microg/kg), talc slurry (5 g) or bleomycin (60 IU) via a chest tube. Saline or buffer was injected into the contralateral side, which served as the control. Arterial blood gases and respiratory and heart rates were monitored for the first 24 h. Plasma levels of TGF-beta1 and TGF-beta2 were measured. Pleurodesis was graded macroscopically from 1 (none) to 8 (symphysis > 50% of hemithorax) at day 14.

RESULTS

At day 14, the pleurodesis score of the TGF-beta2 group (7.7+/-0.6) was similar to that of the talc (7.0+/-1.7) group and significantly higher than that of the bleomycin group (3.3+/-2.3; P < 0.05). No significant differences were seen in arterial blood gas analysis, vital signs and plasma TGF-beta1 and TGF-beta2 concentrations among the three groups.

CONCLUSIONS

Transforming growth factor-beta2 was as effective as talc and more so than bleomycin in inducing pleurodesis in sheep. Intrapleural administration of TGF-beta2 appeared safe. No acute changes in gaseous exchange or macroscopic abnormalities were seen following intrapleural TGF-beta2. Importantly, there was no evidence of an increase in systemic TGF-beta levels following its intrapleural administration.

The effect of corticosteroids on pleurodesis induced by doxycycline in rabbits

STUDY OBJECTIVE

To determine if the administration of systemic corticosteroids diminishes the effectiveness of the pleurodesis induced by the intrapleural injection of doxycycline.

STUDY DESIGN

Thirty New Zealand white male rabbits were classified into three groups (n = 10 rabbits), all of which received doxycycline, 10 mg/kg intrapleurally, in a volume of 2 mL. Rabbits in the control group received only the intrapleural injection of doxycycline; the steroid-once group received triamcinolone, 0.8 mg/kg IM, 24 h before the intrapleural injection; and the steroid-weekly group received triamcinolone, 0.8 mg/kg IM, 24 h before the intrapleural injection and weekly over the next 3 weeks. All rabbits had a chest tube placed before the intrapleural administration of doxycycline and underwent pleural fluid aspiration twice daily. The rabbits were killed after 28 days, and the pleura and lungs were examined macroscopically and microscopically.

RESULTS

The administration of corticosteroids resulted in both a significant decrease in the macroscopic adhesion score (p < 0.001) and a tendency toward a decreased microscopic fibrosis score (p = 0.056) after 28 days. Animals receiving weekly corticosteroid injections had lower scores than animals receiving only one injection.

CONCLUSION

This study demonstrates that the administration of corticosteroids (triamcinolone, 0.8 mg/kg) 24 h before the intrapleural injection of doxycycline, 10 mg/kg, decreases the effectiveness of pleurodesis in rabbits. Weekly injections decreased the effectiveness even more. If these results can be extrapolated to humans, efforts should be made to minimize the administration of exogenous corticosteroids when pleurodesis is attempted.

Serious complications with talc slurry pleurodesis

OBJECTIVE

Talc is a highly efficacious and commonly employed agent for chemical pleurodesis, which has generally been felt to be well tolerated. However, increasing reports of adult respiratory distress syndrome (ARDS) have heightened safety concerns. A recent case of ARDS prompted us to review our experience with talc pleurodesis.

METHODOLOGY

We conducted a retrospective review of all patients who received talc slurry pleurodesis at Green Lane Hospital, Auckland, New Zealand, between 1 January 1998 and 31 December 1999 and documented all complications occurring within 48 h of the procedure.

RESULTS

Thirty-three talc pleurodesis were performed on 29 patients, most commonly for a malignant pleural effusion. Complications occurred in 15 patients (52% of procedures). Minor complications included tachycardia (n = 11; 33%), pain (n = 9; 27%), fever (n = 8; 24%) and dyspnoea (n = 4; 12%). Major complications occurred in seven patients with hypoxaemia and hypotension. Two of these patients died; one death directly attributable to ARDS, the other hastened by a talc pleurodesis-related tachycardia.

CONCLUSIONS

These results challenge the assumption that talc pleurodesis is a safe procedure. There were a significant number of serious complications, including a death, from ARDS. Physicians and patients should be aware that complications occur frequently after talc pleurodesis which may be life-threatening or fatal.

Transforming growth factor beta2 induced pleurodesis is not inhibited by corticosteroids

BACKGROUND

Talc and tetracyclines induce pleurodesis by directly injuring the pleura. The injury results in intense inflammation which subsequently leads to fibrosis. Corticosteroids can inhibit talc pleurodesis by reducing the inflammatory process. We hypothesised that transforming growth factor beta2 (TGFbeta2), a fibrogenic cytokine with immunomodulatory functions, could induce effective pleurodesis without generating significant pleural inflammation and therefore remain effective despite co-administration of corticosteroids.

METHODS

Thirty rabbits were divided into two groups. Rabbits in the steroid group received weekly intramuscular injections of triamcinolone diacetate (0.8 mg/kg). Ten rabbits in each group were given 5.0 microg TGFbeta2 intrapleurally via a chest tube while the remaining five received 1.7 microg TGFbeta2. Pleurodesis was graded macroscopically after 14 days from 1 (none) to 8 (>50% symphysis).

RESULTS

TGFbeta2 produced excellent pleurodesis at both 5.0 microg and 1.7 microg doses. The pleural effusions produced after the injection were low in all inflammatory markers. No significant differences were seen between the steroid group and controls in macroscopic pleurodesis scores (7.2 (1.3) v 7.1 (1.2)), levels of inflammatory markers in the pleural fluids (leucocyte 1107 (387)/mm(3) v 1376 (581)/mm(3); protein 3.1 (0.3) mg/dl v 2.9 (0.3) mg/dl, and LDH 478 (232) IU/l v 502 (123) IU/l), and the degree of microscopic pleural fibrosis and pleural inflammation.

CONCLUSIONS

TGFbeta2 can induce effective pleurodesis and remains effective in the presence of high dose parenteral corticosteroids.

Transforming growth factor β2 induced pleurodesis is not inhibited by corticosteroids

BACKGROUND

Talc and tetracyclines induce pleurodesis by directly injuring the pleura. The injury results in intense inflammation which subsequently leads to fibrosis. Corticosteroids can inhibit talc pleurodesis by reducing the inflammatory process. We hypothesised that transforming growth factor β2 (TGFβ2), a fibrogenic cytokine with immunomodulatory functions, could induce effective pleurodesis without generating significant pleural inflammation and therefore remain effective despite co-administration of corticosteroids.

METHODS

Thirty rabbits were divided into two groups. Rabbits in the steroid group received weekly intramuscular injections of triamcinolone diacetate (0.8 mg/kg). Ten rabbits in each group were given 5.0 μg TGFβ2 intrapleurally via a chest tube while the remaining five received 1.7 μg TGFβ2. Pleurodesis was graded macroscopically after 14 days from 1 (none) to 8 (>50% symphysis).

RESULTS

TGFβ2produced excellent pleurodesis at both 5.0 μg and 1.7 μg doses. The pleural effusions produced after the injection were low in all inflammatory markers. No significant differences were seen between the steroid group and controls in macroscopic pleurodesis scores (7.2 (1.3)v 7.1 (1.2)), levels of inflammatory markers in the pleural fluids (leucocyte 1107 (387)/mm3v 1376 (581)/mm3; protein 3.1 (0.3) mg/dl v 2.9 (0.3) mg/dl, and LDH 478 (232) IU/l v 502 (123) IU/l), and the degree of microscopic pleural fibrosis and pleural inflammation.

CONCLUSIONS

TGFβ2can induce effective pleurodesis and remains effective in the presence of high dose parenteral corticosteroids.

The many faces of transforming growth factor-beta in pleural diseases

Transforming growth factor (TGF)-beta is responsible for critical regulatory functions in many physiologic and pathologic processes. Emerging evidence suggests that these roles also apply to a multitude of pleural diseases. Both mesothelial cells and infiltrating cells in the pleural space can produce TGFbeta, and elevated TGFbeta concentrations have been found in pleural effusions and in pleural tissues during disease processes. Recent animal studies have suggested that TGFbeta can induce significant pleurodesis and probably plays a central role in the pathogenesis of pleural fibrosis. Paradoxically, TGFbeta may also stimulate increased pleural fluid formation, in part by inducing the production of vascular endothelial growth factor. TGFbeta also participates in the regulation of pleural inflammation and cell proliferation. Further research into the roles of TGFbeta in the pathogenesis of various pleural diseases is needed and may lead to the development of novel treatment strategies.