Cirugía Española

Cirugía Española

Volume 100, Issue 4, April 2022, Pages 209-214
Cirugía Española

Original article
Efficacy of hyperthermia pleurodesis: A comparative experimental study on serous membrane of abdominopelvic and thoracic cavities of ratsEficacia de la pleurodesis por hipertermia: un estudio experimental comparativo sobre la membrana serosa de las cavidades abdominopélvica y torácica de ratas

https://doi.org/10.1016/j.ciresp.2021.01.004Get rights and content

Abstract

Background

Pleurodesis is a common technique for treating the accumulation of air or liquid in the pleural space caused by pneumothorax or pleural effusion, it is based on the bounding of pleural layers through induced inflammatory lesions. There are several pleurodesis procedures.

Objectives

To test and describe the inflammatory effect of hyperthermia on the pleural and peritoneal mesothelia of rats, with the aim of testing the effectiveness of this process for inducing pleurodesis.

Methods

35 Sprague-Dawley (male/female) rats were randomized into four treatment groups: Group A (Talc, 10 individuals); group B (control, 5 individuals); group C (hyperthermic isotonic saline, 10 individuals); and group D (filtrate air at 50°, 10 individuals). Inflammatory effect of hyperthermia was the primary outcome parameter.

Results

In the talc group, minimal adhesions between both pleural and peritoneal layers were observed in seven rats. Talc produced peritoneal mesothelium inflammation and fibrosis associated to foreign body giant cells in 80% (8/10) of the sample. Furthermore, clear evidence of a granulomatous foreign-body reaction was detected. No macroscopic and/or microscopic damage was registered in the remaining three groups (control, hyperthermic, and filtrate air).

Conclusions

Talc is an excellent method for producing pleuro-peritoneal inflammatory lesions. On the contrary, hyperthermia apparently does not induce the macroscopic and microscopic damage that is required for efficient pleurodesis. Therefore, hyperthermia should not be used for pleurodesis procedures.

Resumen

Introducción

La pleurodesis es una técnica común como tratamiento de la patología pleural, ya sea en el neumotórax o el derrame pleural; se basa en la delimitación de las capas pleurales mediante lesiones inflamatorias inducidas. Existen múltiples procedimientos para conseguir una sínfisis pleural.

Objetivo

Estudiar y describir el efecto inflamatorio de la hipertermia sobre el mesotelio pleural y peritoneal de ratas con el objetivo de valorar si presenta un efecto sinfisiante y por tanto útil para conseguir la pleurodesis.

Métodos

Treinta y cinco ratas Sprague-Dawley (hembras/machos) fueron aleatorizadas en 4 grupos de tratamiento: grupo A (talco, 10 animales); grupo B (control, 5 animales); grupo C (suero salino hipertérmico: 10 animales), y grupo D (aire filtrado a 50°, 10 animales).

Resultados

En el grupo de talco se evidenciaron adherencias entre las dos membranas pleurales y peritoneales en 7 animales. Se observó inflamación, fibrosis asociada a células gigantes de cuerpos extraño en el 80% (8/10) del mesotelio peritoneal. Paralelamente, se observó reacción granulomatosa a cuerpo extraño. No se registraron lesiones macroscópicas ni microscópicas en el resto de grupos estudiados (control, hipertermia y aire filtrado).

Conclusión

El talco es un excelente método para producir inflamación a nivel del mesotelio pleural y peritoneal. Por el contrario, la hipertermia no parece inducir lesiones macroscópicas ni microscópicas requeridas para conseguir una pleurodesis eficaz.

Introduction

Pleurodesis is the main treatment choice to prevent the accumulation of air or liquid in the pleural space caused by pneumothorax or pleural effusion. There are different pleurodesis procedures: chemical pleurodesis, mechanical pleurodesis or a combination of both. There are different chemical agents such as talc, polidocanol, tetracyclines, autologous blood, iodopovidone or hyperthermic saline solution with a greater or lesser effectiveness.1, 2, 3, 4, 5, 6, 7

Few studies have shown the efficacy of hyperthermia without chemotherapy as a sclerosing agent to treat malignant pleural effusion.7, 8, 9 Pneumothorax is defined as the collection of air in the pleural space between the lung and the chest wall. Primary pneumothoraces can arise in otherwise healthy people without any lung disease. In a recent epidemiological study, primary spontaneous pneumothorax (PSP) occurred in 7.4–18 cases (age-adjusted incidence) per 100,000 population each year in males, and 1.2–6 cases per 100,000 population each year in females. The exact pathogenesis of PSP is unknown.10 Secondary spontaneous pneumothorax has its origin on various diseases, including infectious processes, interstitial lung disease, connective tissue disease, and chronic obstructive pulmonary disease (COPD). Among the associated conditions, cystic fibrosis and COPD are the most commonly reported.11, 12, 13 Pleural effusion is a common complication of advanced cancers that may affect the performance status of patients. Pleural effusion can also exacerbate symptoms such as dyspnea and chest pain, which can be distressing for patients. These patients may undergo repeated interventions in search of relief from their symptoms.14

The aim of this paper is to study the changes in the pleural and/or peritoneal cavity after hyperthermia-induced pleurodesis (hyperthermic saline solution or filtrate hot air), testing the comparative capability of acute hyperthermia for producing pleurodesis in rats.

Section snippets

Animal groups

Our study included 35 male and female rats (Sprague-Dawley) that were 6–9 months old and weighed 400–900 g. The Ethics Committee of our home institution (Universitat de Barcelona) approved the experimental procedures before. All animals were maintained in adequate cages and fed according to protocol. The animal laboratory at the Barcelona University housed the rat cages and was also the place where the operations took place. Our study was performed in the peritoneal cavity of the test-rats,

Results

The intrapleural administration of talc, saline solution or a filtrate hot air did not cause distress or other complications in any of the animals. We did not record significant differences in the mean weights among the four groups of animals (p > 0.05).

Four of the five rats (80%) of group A that received intraperitoneal and intrapleural administrations of talc showed few adhesions on the injection side between the pleural layers and also between the peritoneal layers. The microscopic study of

Discussion

Our results indicate that acute hyperthermia does not induce macroscopic or microscopic lesions such as inflammation, fibrosis or proliferation in peritoneal space. However, Giovanella et al.22 suggested that hyperthermia is tumoricidal and induces high levels of proinflammatory proteins and cytokines, such as MIP-2, KC, RANTES and MCP-5. Also, hyperthermia may be chemo-attractant for polymorphonuclear leukocytes, monocytes and macrophages.16 Hyperthermia probably produces these changes acutely

Conclusions

Through this experimental study, we can conclude that acute hyperthermia apparently does not induce fibrosis, proliferation or inflammation in the mesothelium, thus not producing the macroscopic and microscopic lesions that are requisite for pleurodesis. Because of that, it should not be considered to perform pleurodesis. However, talc is an excellent method for producing pleuro-peritoneal inflammatory lesions.

Authors’ contributions

RR generated the hypothesis. IE, CD, AU, AG, FR and RR designed the study. RP performed the pathological study. FR and RR wrote the manuscript.

Conflict of interest

The authors declare that they have no conflict of interest.

Acknowledgments

This study was supported by a Research Fund of Barcelona University (Project number: ACESB11/05).

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