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

Systemic Inflammatory Response to Different Sclerosing Agents as a Predictor of Pleurodesis Outcome

BACKGROUND/AIM

The objectives of this study were to evaluate systemic inflammation using different sclerosing agents and to estimate the prediction of systemic inflammation for the efficacy of pleurodesis.

PATIENTS AND METHODS

Ninety-six patients with recurrent and symptomatic malignant pleural effusion were enrolled in this retrospective study. We used serum C-reactive protein (CRP) levels, serum leukocyte counts and neutrophil-to-lymphocyte ratios (NLRs) as parameters of systemic inflammatory reactions. Evaluations of these parameters were performed before and 24 h after pleurodesis.

RESULTS

Pleurodesis was successful in 81 (84.4%) patients. The non-graded talc induced the highest changes in serum CRP levels, total white blood cell and neutrophil counts compared to other agents, while mitoxantrone induced the lowest. Graded talc and bleomycin induced the same levels of changes in serum CRP levels and serum leukocyte counts. The change in serum NLR was the same for all agent groups. Logistic regression confirmed that a change in serum CRP levels [odds ratio (OR)=0.92, p=0.002] and previous chemotherapy (OR=3.31, p=0.012) were independent predictors of pleurodesis efficacy.

CONCLUSION

Pleurodesis agents induced a systemic inflammatory response at different levels. The change in serum CRP levels could be useful for predicting the success of pleurodesis.

Primary human mesothelial cell culture in the evaluation of the inflammatory response to different sclerosing agents used for pleurodesis

The mechanisms of chemical pleurodesis are still not fully explained. We aimed to evaluate the feasibility of using primary biopsy‐derived human mesothelial cells to establish an in vitro culture and to assess the response of pleural mesothelial cells to different sclerosing agents. Talc, povidone‐iodine, doxycycline, and TGF‐β were used at different doses to stimulate pleural mesothelial cells. After 6 and 24 h, mRNA expression of interleukin (IL)‐1β, IL‐6, IL‐8, TGF‐β, MCP‐1, IL‐17A, and MMP9 was measured in cultured cells, and the protein level of IL‐1β, IL‐6, and IL‐8 was measured in the culture supernatant. The most pronounced response was observed after talc exposure. It was expressed as an increase in IL‐1β concentration in culture supernatant after 24 h of higher talc dose stimulation compared to 6 h of stimulation (17.14 pg/ml [11.96–33.32 pg/ml] vs. 1.84 pg/ml [1.81–1.90 pg/ml], p = 0.02). We showed that culture pleural mesothelial cells isolated from pleura biopsy specimens is feasible. Inflammatory responses of mesothelial cells to different sclerosants were highly variable with no consistent pattern of mesothelium reaction neither in terms of different sclerosing agents nor in the time of the most significant reaction. We demonstrated that pro‐inflammatory mesothelial response includes an increase in IL‐1β mRNA expression and protein production. This may suggest the role of IL‐1β in the formation and maintenance of the inflammatory response during pleurodesis.

Chemical pleurodesis - a review of mechanisms involved in pleural space obliteration

Chemical pleurodesis is a therapeutic procedure applied to create the symphysis between the parietal and visceral pleura by intrapleural administration of various chemical agents (e.g. talk, tetracycline, iodopovidone, etc.). The two major clinical conditions treated with chemical pleurodesis are recurrent pleural effusion (PE) and recurrent spontaneous pneumothorax. Although the history of chemical pleurodesis began over a century ago, detailed data on the mechanisms of action of sclerosing agents are highly incomplete. The following article aims to present the state of knowledge on this subject.It is believed that mesothelial cells are the main structural axis of pleurodesis. In response to sclerosing agents they secrete a variety of mediators including chemokines such as interleukin 8 (IL-8) and monocyte chemoattractant protein (MCP-1), as well as growth factors - vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF), basic fibroblast growth factor (bFGF) and transforming growth factor- β (TGF-β). Numerous data suggest that intact mesothelial cells and the above cytokines play a crucial role in the initiation and maintenance of different pathways of pleural inflammation and pleural space obliteration.It seems that the process of pleurodesis is largely nonspecific to the sclerosant and involves the same ultimate pathways including activation of pleural cells, coagulation cascade, fibrin chain formation, fibroblast proliferation and production of collagen and extracellular matrix components. Of these processes, the coagulation cascade with decreased fibrinolytic activity and increased fibrinogenesis probably plays a pivotal role, at least during the early response to sclerosant administration.A better understanding of various pathways involved in pleurodesis may be a prerequisite for more effective and safe use of various sclerosants and for the development of new, perhaps more personalized therapeutic approaches.

Clinical outcomes of chemical pleurodesis using a minocycline

Background:

Pleurodesis is often used to prevent the re-accumulation of a malignant pleural effusion (MPE). Intrapleural urokinase (IPUK) therapy facilitates lung re-expansion for patients with loculated MPE or a trapped lung that allows subsequent pleurodesis. MPE management has been traditionally regarded as a symptomatic treatment. We tried to evaluate their impact on patient survival.

Methods:

There were 314 consecutive patients with symptomatic MPE that underwent minocycline pleurodesis with (n = 109) and without (n = 205) the antecedent IPUK therapy between September 2005 and August 2015, who were recruited for the pleurodesis outcome and survival analysis.

Results:

The rate of successful pleurodesis was similar between the simple pleurodesis group and the IPUK therapy group followed by the pleurodesis group (69.0% versus 70.5%; p = 0.804). The patients who succeeded pleurodesis had a longer survival rate than those who failed in either the simple pleurodesis group (median, 414 versus 100 days; p < 0.001) or the IPUK therapy followed by pleurodesis group (259 versus 102 days; p < 0.001). The survival differences remained when the lung and breast cancer patients were studied separately.

Conclusion:

Successful pleurodesis translated into a better survival rate that promotes performing pleurodesis on lung re-expansion. The apparent shorter survival of the patients with loculated MPE or trapped lung, and those that did not respond to the IPUK therapy, lowered the probability of the survival benefit through the simple physical barrier by the fibrin formation to prevent the tumor spreading. The successfully induced inflammatory response by minocycline is supposed to prohibit the tumor invasion and metastasis. Further studies are warranted to clarify the mechanism and provide opportunities to develop novel therapeutic strategies.

Monoclonal antibodies anti-TGFβ1 and anti-VEGF inhibit the experimental pleurodesis induced by silver nitrate

BACKGROUND

The mechanisms underlying pleural inflammation and pleurodesis are poorly understood. We hypothesized that the cytokines transforming growth factor β (TGFβ1) and vascular endothelial growth factor (VEGF) play a major role in pleurodesis after intrapleural silver nitrate (SN) injection.

METHOD

Forty rabbits received intrapleurally 0.5% SN alone or 0.5% SN + anti-TGFβ1, anti-IL-8, or anti-VEGF. After 28 days, the animals were euthanized and macroscopic pleural adhesions, microscopic pleural fibrosis, and collagen deposition were analyzed for characterization of the degree of pleurodesis (scores 0-4).

RESULTS

Scores of pleural adhesions, pleural fibrosis, total collagen, and thin collagen fibers deposition after 28 days were significantly lower for 0.5% SN + anti-TGFβ1 and 0.5% SN + anti-VEGF. Significant correlations were found between macroscopic adhesion and microscopic pleural fibrosis with total collagen and thin collagen fibers.

CONCLUSIONS

We conclude that both TGFβ1 and VEGF, but not IL-8, mediate the pleural inflammatory response and pleurodesis induced by SN.