Intrapleural Low-Dose Silver Nitrate Elicits More Pleural Inflammation and Less Systemic Inflammation Than Low-Dose Talc

Application of autologous blood patch in patients with non-expanded lungs and persistent air leak

Background

This study aims to evaluate the effectiveness of pleurodesis procedure by ensuring the expansion of the lung and occluding lung parenchyma leaks with an autologous blood patch.

Methods

A total of 24 patients (17 males, 7 females; mean age 59.9±12.2 years; range, 30 to 86 years) who underwent autologous blood patch pleurodesis in our clinic between November 2015 and November 2019 were retrospectively analyzed. The patients were not eligible to undergo chemical pleurodesis due to a nonexpandable lung or poor general condition. Demographic and clinical characteristics of the patients and postoperative data were evaluated.

Results

The air leak stopped within 48 h after autologous blood patch pleurodesis in seven patients. The air leak significantly decreased in 13 patients, while it remained unchanged in four patients. A Heimlich valve was placed in the patients in whom the air leak stopped or significantly decreased. The follow-up chest X-rays showed that the respective lungs of these patients became completely expandable.

Conclusion

Our study results suggest that the autologous blood patch procedure is a favorable option for the patients who are unable to benefit much from the conventional chemical pleurodesis methods due to contraindications to surgery or the presence of non-expandable lungs.

Influence of the progression of pleural neoplasia on the outcome of pleurodesis in mice

Purpose: Experimental study aimed at evaluating whether pleural neoplastic disease is associated with the degree of pleural fibrosis over time caused by talc pleurodesis. The study describes changes in levels of inflammatory mediators and determines whether the course of time involved in progression of neoplastic pleural disease is the factor that influences safety of talc pleurodesis usage in mice.

Materials and Methods: Animals were randomized into two groups: Cancer group (CG) that received intrapleural injection of Lewis cells or Saline group (SG) that received saline injection. After, the animals were subdivided into Early (pleurodesis 3 days after pleural injection) and Late (pleurodesis 7 days after pleural injection) groups. Half of the animals in each group were euthanized 24 hours after pleurodesis (to obtain the inflammatory data); the remaining animals were killed after 8 days (to obtain the scores of pleural fibrosis).

Results: CGs had lower fibrosis scores than SGs comparing early phases to late phases. Inflammation scores were lower in CGs, particularly in Late group. In SGs the inflammation was intense in 100% of the animals.

In Late CG group pleural adhesions had the lowest scores; we found intense fibrosis only in SGs. VEGF and LDH levels had increased in animals with cancer, particularly in Late group. Systemic distribution of talc occurred only in Late CG.

Conclusions: The time for pleural neoplasia to evolve is inversely proportional to the degree of pleural fibrosis. Earlier pleurodesis yielded the best results related to fibrosis, with less systemic inflammation and is safer in mice.

Silver Nanoparticles Induce Mitochondrial Protein Oxidation in Lung Cells Impacting Cell Cycle and Proliferation

Silver nanoparticles (AgNPs) are widely used nanomaterials in both commercial and clinical biomedical applications, due to their antibacterial properties. AgNPs are also being explored for the treatment of cancer in particular in combination with ionizing radiation. In this work, we studied the effects of AgNPs and ionizing radiation on mitochondrial redox state and function in a panel of lung cell lines (A549, BEAS-2B, Calu-1 and NCI-H358). The exposure to AgNPs caused cell cycle arrest and decreased cell proliferation in A549, BEAS-2B and Calu-1, but not in NCI-H358. The mitochondrial reactive oxygen species (ROS) and protein oxidation increased in a time- and dose-dependent manner in the more sensitive cell lines with the AgNP exposure, but not in NCI-H358. While ionizing radiation also induced changes in the mitochondrial redox profiles, in general, these were not synergistic with the effects of AgNPs with the exception of NCI-H358 and only at a higher dose of radiation.

Talc Pleurodesis: A Medical, Medicolegal, and Socioeconomic Review

BACKGROUND

Talcum has been used in pleurodesis for more than 8 decades. Despite a wealth of research, controversy remains over the optimal sclerosant for pneumothorax and pleural effusions. Talc's historical primacy has been challenged because of its potential for pulmonary toxicity, possible carcinogenicity, and recent concerns surrounding availability and legal liability, thus making this an ideal time for a review.

METHODS

This systematic review of the talc literature, focused on publications after the year 2000, evaluated mechanism of action, efficacy, side effect profile, and alternative sclerosants; included is an overview of current socioeconomic and legal controversies.

RESULTS

The data support talc as the most effective agent for pleurodesis. There is evidence to suggest that mean particle size has a direct relationship with the side effect profile and that significant hypoxemic events after talc administration are exceedingly rare when using available graded talc preparations. Concerns regarding the development of malignant diseases after topical talc application remain incompletely resolved but appear related to cosmetic powder preparations that were contaminated with asbestos. Purified talc in the pleural space has not been implicated. Recent difficulties accessing commercial talc preparations have been solved. Although safe and effective talc alternatives do exist, these agents are not as well studied.

CONCLUSIONS

Talc pleurodesis with modern, purified, graded talc preparations is safe and highly effective. Talc is an inexpensive and accessible option that remains appropriate for pleurodesis despite existing controversies.

Management of Malignant Lung Entrapment, the Oncothorax

Pleural metastasis is a common occurrence in up to 30% of patients with metastatic cancer. When lung entrapment and loculation of fluid occur, treatment is more difficult and we have named this condition "oncothorax." The malignant adhesions that entrap the lung in an oncothorax are not typically amenable to surgical decortication. The standard approach for managing these patients is to place an indwelling catheter. Other options may include pleurectomy and decortication, intrapleural hyperthermic chemoperfusion, and intrapleural photodynamic therapy. However, these procedures should be provided selectively depending on patient performance status, extent of metastatic disease, and level of experience.

Silver Nanoparticles Alter Cell Adhesion and Proliferation of Sheep Primary Mesothelial Cells

BACKGROUND

Human exposure to engineered nanoparticles has been linked to pleural effusion, inflammation and fibrosis. Silver nanoparticles (AgNPs) are widely used in medical and domestic products, increasing the risk of occupational and domestic exposure. We assessed the influence of AgNPs on adhesion and proliferation of sheep primary pleural mesothelial cells.

MATERIALS AND METHODS

Cells were used for cell adhesion (90 min) and proliferation experiments (3 days) while exposed to 20 nm and 60 nm AgNPs (0.2 μg/ml and 2 μg/ml) using colorimetric assays.

RESULTS

Exposure to 0.2 μg/ml of 20 nm and 60 nm AgNPs significantly increased cell adhesion, while at 2 μg/ml this effect was not elicited. Cell proliferation was significantly increased by both 20 nm and 60 nm AgNPs at 0.2 μg/ml, while at 2 μg/ml this effect was only elicited by the 60 nm AgNPs.

CONCLUSION

AgNPs alter the adhesive and proliferative properties of primary pleural mesothelial cells.

Is silver nitrate an effective means of pleurodesis?

A best evidence topic was written according to a structured protocol. The question addressed was whether silver nitrate (SN) is an effective means of pleurodesis. A total of 42 papers were identified using the reported search, of which 8 represented the best evidence to address the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. Three studies assessed the efficacy of SN in inducing pleurodesis in patients with malignant pleural effusion (MPE). Using intrapleural injections of SN in concentrations of 0.5-1%, they reported success rates of 89-96% at 30 days. One of these studies compared SN with talc slurry and found equally effective pleurodesis at monthly intervals up to 4 months (P = 0.349-1). Another two studies retrospectively reviewed the efficacy of thoracosopic SN instillation (1 or 10%) in patients with primary spontaneous pneumothorax (PSP). Recurrence rates were 0-1.1% during long-term follow-up. One of these compared SN with simple drainage and reported a therapeutic gain of 45 ± 30% (95% CI) with SN, at the cost of increased analgesia consumption, chest drainage and hospital stay. Finally, three studies reported the results of the comparison of intrapleural injections of SN, talc or tetracycline in inducing pleurodesis in rabbits. SN was equally effective with tetracycline and superior to talc at producing pleurodesis, with lower concentrations of SN (0.1%) resulting in significantly attenuated systemic inflammatory response when compared with either higher SN concentrations (0.5%) or talc. Although not commonly used, available evidence suggests that SN is an effective agent in inducing pleurodesis in patients with either MPE or PSP. Compared with universally employed talc, it seems to result in at least similar short-term recurrence rates for MPE, with a demonstrably good side-effect profile; the longer-term efficacy is, as yet, undetermined. In cases of PSP, evidence suggests that thoracoscopic SN instillation is at least as effective as talc, with potentially fewer systemic side effects.

Safety and systemic consequences of pleurodesis with three different doses of silver nitrate in patients with malignant pleural effusion

BACKGROUND

Silver nitrate (SN) is an alternative to talc pleurodesis in patients with malignant pleural effusion (MPE). Nevertheless, SN complications have not been thoroughly investigated so far.

OBJECTIVE

To evaluate frequent adverse events (AE) of SN treatment at three different doses for pleurodesis in patients with MPE. The secondary objective was to evaluate systemic inflammation, efficacy and quality of life in these patients.

METHODS

A double-blind, randomized, clinical trial was conducted in patients with recurrent MPE at a tertiary university hospital. The study patients underwent pleural catheter insertion and were randomly assigned to one of the three pleurodesis groups treated with 30 ml 0.3%, 30 ml 0.5% or 60 ml 0.3% SN. Patients were discharged 3 days after the procedure, and returned to follow-up visits on days 10 and 30. During follow-up, AE, inflammatory markers, quality of life and CT scans were systematically assessed and documented.

RESULTS

Sixty patients (11 males and 49 females, median age 62.13 years) were included. Overall, 199 AE were observed, including 23 serious AE. Grade 1/2 metabolic AE, such as increases in creatinine and liver enzymes, were the most frequent. Grade 3/4 hypoxia was observed in 13 patients. Four patients died, 3 due to disease progression and in 1 patient death was possibly related to pleurodesis. C-reactive protein levels increased in a dose-dependent manner and peaked 48 h after pleurodesis. No significant difference was observed among groups regarding quality of life or clinical/radiological recurrence.

CONCLUSION

Hypoxia was the most significant AE following SN pleurodesis; mild metabolic events were very common. SN instillation causes substantial dose-dependent systemic inflammatory responses.

Blockage of vascular endothelial growth factor (VEGF) reduces experimental pleurodesis

BACKGROUND AND OBJECTIVE

Chemical pleurodesis controls recurrent malignant pleural effusion. The mechanism that determines pleural symphysis involves the action of vascular endothelial growth factor (VEGF). We assessed the influence of the anti-VEGF antibody (bevacizumab) on pleurodesis induced by talc or silver nitrate and analyzed the temporal development of pleural angiogenesis.

METHODS

Sixty New Zealand rabbits received intrapleural injection (2mL) of talc (400mg/kg) or 0.5% silver nitrate. In each group, half of the animals received an intravenous injection of bevacizumab 30min before the sclerosing agent. Five animals from each group were euthanized 7, 14, or 28 days after the procedure. Adhesions and inflammation (scores: 0-4), thickness (μm), vascular density (vessels/field), and collagen fibers (μm(2)) were evaluated in the visceral pleura.

RESULTS

Antibody anti-VEGF interferes in pleurodesis induced by talc or silver nitrate. Pleural inflammation was discreet with no difference between the groups, regardless the anti-VEGF treatment. Concerning the vascular density of the visceral pleura, a smaller number of neoformed vessels was noted in the animals that received bevacizumab. In the animals receiving silver nitrate, the decrement in adhesions and vascular density was associated with reduced thick and thin collagen fibers, resulting in less pleural thickness.

CONCLUSION

The anti-VEGF antibody inhibits adhesions between pleural layers. Despite being an experimental study in animals with normal pleura, the results call attention to a likely lack of success in pleurodesis when VEGF blockers are used.

Early and late morbidity and mortality and life expectancy following thoracoscopic talc insufflation for control of malignant pleural effusions: a review of 400 cases

BACKGROUND

Malignant pleural effusion is a common sequelae in patients with certain malignancies. It represents a terminal condition with short median survival (in terms of months) and the goal is palliation. Aim of our study is to analyze morbidity, mortality and life expectancy following videothoracoscopic talc poudrage.

MATERIALS AND METHODS

From September 2004 to October 2009, 400 patients underwent video-assisted thoracic surgery (VATS) for malignant pleural effusion. The conditions of patients were assessed and graded before and after treatment concerning morbidity, mortality, success rate of pleurodesis and median survival.

RESULTS

The median duration of follow up was 40 months (range 4-61 months). All patients demonstrated notable improvement in dyspnea. Intraoperative mortality was zero. The procedure was well tolerated and no significant adverse effects were observed. In hospital mortality was 2% and the pleurodesis success rate was 85%. A poor Karnofsky Performance Status and delay between diagnosis of pleural effusion and pleurodesis were statistically significant factors for in-hospital mortality. The best survival was seen in breast cancer, followed by ovarian cancer, lymphoma and pleural mesothelioma.

CONCLUSIONS

Video-assisted thoracoscopic talc poudrage is an effective and safe procedure that yields a high rate of successful pleurodesis and achieves long-term control with marked dyspnea decrease.

Monoclonal anti-vascular endothelial growth factor antibody reduces fluid volume in an experimental model of inflammatory pleural effusion

BACKGROUND AND OBJECTIVE

Vascular endothelial growth factor (VEGF) is known to increase vascular permeability and promote angiogenesis. It is expressed in most types of pleural effusions. However, the exact role of VEGF in the development of pleural effusions has yet to be determined. The anti-VEGF mAb, bevacizumab, has been used in the treatment of cancer to reduce local angiogenesis and tumour progression. This study describes the acute effects of VEGF blockade on the expression of inflammatory cytokines and pleural fluid accumulation.

METHODS

One hundred and twelve New Zealand rabbits received intrapleural injections of either talc or silver nitrate. In each group, half the animals received an intravenous injection of bevacizumab, 30 min before the intrapleural agent was administered. Five animals from each subgroup were sacrificed 1, 2, 3, 4 or 7 days after the procedure. Twelve rabbits were used to evaluate vascular permeability using Evans's blue dye. Pleural fluid volume and cytokines were quantified.

RESULTS

Animals pretreated with anti-VEGF antibody showed significant reductions in pleural fluid volumes after talc or silver nitrate injection. IL-8 levels, vascular permeability and macroscopic pleural adhesion scores were also reduced in the groups that received bevacizumab.

CONCLUSIONS

This study showed that bevacizumab interferes in the acute phase of pleural inflammation induced by silver nitrate or talc, reinforcing the role of VEGF as a key mediator in the production of pleural effusions. The results also suggest that bevacizumab should probably be avoided in patients requiring pleurodesis.

Influence of parecoxib (cox-2 inhibitor) in experimental pleurodesis

BACKGROUND

The intrapleural instillation of a sclerosing agent produces an inflammatory process frequently followed by pain. The treatment can include the use of analgesics or anti-inflammatory drugs. Previously, it was demonstrated (experimental studies) that corticoids and nonsteroidal anti-inflammatory drugs (diclofenac) reduce the inflammation and fibrosis produced by talc but not by transforming growth factor-beta or silver nitrate. The objective of this study was to determine whether parecoxib (COX-2 inhibitor) affects pleurodesis induced by talc or silver nitrate.

METHODS

140 rabbits received intrapleural injection (2mL) of 400mg/kg of talc or 0.5% silver nitrate. A subgroup of 70 animals received additional daily intramuscular parecoxib (1mg/kg). They were sacrificed at 4, 24, 48, 72h or 7, 14, or 28 days after the procedure. The pleural fluid was quantified; biochemical examinations (glucose, lactic dehydrogenase, and proteins) and immunologic dosages (interleukin-8, vascular endothelial growth factor, and transforming growth factor-beta(1)) were analyzed in pleural fluid and blood. Finally, macro- and microscopic pleura and lung studies were performed.

RESULTS

Evaluation after 28 days demonstrated that parecoxib reduced pleural and pulmonary inflammation but not pleural adhesions. The changes were observed precociously (congruent with 72h) and were more evident after silver nitrate injection.

CONCLUSION

Systemic parecoxib injection does not interfere with talc or silver nitrate pleurodesis. These results suggest that use of COX-2 inhibitors can be considered and depending of the results of other studies, recommended in human pleurodesis.