The effects of intrapleural polyclonal anti-tumor necrosis factor alpha (TNF alpha) Fab fragments on pleurodesis in rabbits

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.

Low-dose Talc Plus Low-dose Doxycycline for Pleuroscopic Pleurodesis: Initial Experience

OBJECTIVE

We performed a retrospective review of the use of the combination of talc and doxycycline for pleurodesis in patients.

METHODS

There were 33 sequential cases over a 2-year period. Doses of doxycycline (250 mg) and talc (2.5 g) were half the "usual" doses.

RESULTS

Thirty-three cases were identified (20 women, 13 men, average age 64 y). No immediate perioperative complications were noted. Chest tube duration averaged 4.2±2.6 days. Total drainage averaged 880 mL. Length of stay after procedure in the outpatient group was 4.8±3.1 days. Eleven patients (33%) reported persistence or worsening dyspnea in the immediate postoperative period. Only 2 developed respiratory distress; neither had any parenchymal changes on chest radiology or required ventilatory support. Other immediate postoperative events included chest pain in 18 patients (54%) and fever in 3. Follow-up imaging was available for 29 patients, an average of 3.9 months postoperatively. Twenty patients (69%) had complete pleurodesis, 4 patients (14%) had partial pleurodesis, and 5 (17%) failed. In no case did follow-up imaging demonstrate new adult respiratory distress-like infiltrates.

CONCLUSIONS

The combination of low-dose doxycycline with low-dose talc appears to be a safe and rational approach to pleuroscopic pleurodesis in patients. The success rate matched that of the literature for talc alone. The side-effect profile was reasonable. No severe sequelae were observed. A prospective clinical trial seems warranted.

Who Gains Most? A 10-Year Experience With 611 Thoracoscopic Talc Pleurodeses

BACKGROUND

Thoracoscopic talc pleurodesis is a therapeutic option for recurrent pleural effusion.

METHODS

This retrospective study included 611 patients who underwent thoracoscopic talc pleurodesis between 1994 and 2003. We analyzed the risk factors, efficiency, outcome, follow-up, and survival, while taking into consideration primary disease and general condition.

RESULTS

The mean follow-up was 319 days (range, 31 to 1994). A total of 105 (17.2%) of 611 patients died within 30 days after treatment. Risk factors for death within 30 days included a Karnofsky index of less than 50%, a body mass index of less than 25 kg/m2, malignant disease, and male gender. Treatment was successful in 347 (68.6%) of 506 patients, and 451 (89.1%) reported an improvement in symptoms. Previous thoracic irradiation and a chest tube drainage time exceeding 10 days negatively influenced the outcome of pleurodesis. The survival rate was negatively influenced by a preoperative Karnofsky index of less than 60% and by malignant disease.

CONCLUSIONS

Patients with pleural effusion due to malignant disease gain from early pleurodesis. The most favorable outcome after talc pleurodesis was seen in women whose lungs were fully expandable, in patients whose Karnofsky index exceeded 60%, in patients whose body mass index was greater than 25 kg/m2, and in patients with benign disease.

The effects of erythromycin on the viability and the secretion of TNF-alpha and TGF-beta1 and expression of connexin43 by human pleural mesothelial cells

OBJECTIVE

The mechanism by which erythromycin produces pleurodesis remains unknown. The purpose of this study was to investigate the effects of erythromycin on human pleural mesothelial cell (HPMC) viability, the secretion of tumour necrosis factor-alpha (TNF-alpha) and transforming growth factor-beta(1) (TGF-beta(1)) and the level of expression of connexin43.

METHODOLOGY

HPMC were incubated with different concentrations of erythromycin. The inhibitory effects of erythromycin on HPMC growth were measured using a tetrazolium-based colorimetric assay. The levels of TNF-alpha and TGF-beta(1) in supernatants were measured by ELISA and levels of connexin43 were assessed by Western blot.

RESULTS

Erythromycin injured HPMC in a dose and time-dependent manner. The secretion of both TNF-alpha and TGF-beta(1) by HMPC increased significantly when they were incubated with 100 mg/L erythromycin for 3 or 5 days. The levels of connexin43 in HPMC decreased after incubation with 100 mg/L erythromycin and no relationship was observed between the levels and incubation time.

CONCLUSIONS

Erythromycin injures HPMC in a dose- and time-dependent manner and results in the secretion of TNF-alpha and TGF-beta(1). This is one possible mechanism of pleurodesis with erythromycin. Furthermore, erythromycin decreased the levels of connexin43 in HPMC, which could possibly affect the response of HPMC to pleurodesis with erythromycin.

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.

Chemotherapeutic management of malignant pleural effusion

The management of malignant pleural effusions are a common, and sometimes difficult, therapeutic problem. This article reviews the currently available sclerosing agents and discusses novel agents that show promise for the future. Talc, tetracycline and bleomycin are currently the most widely used agents but none is an ideal sclerosant and certain adverse effects are of concern. Novel agents, particularly transforming growth factor (TGF)-beta(2) and metalloproteinase inhibitors, are being investigated, and the increase in knowledge into the mechanisms of pleural fluid formation and pleurodesis will hopefully lead to the development of targeted therapy in the future.

Matrix metalloproteinases production in malignant pleural effusions after talc pleurodesis

In this study we have evaluated the modifications of matrix metalloproteinases (MMPs) in malignant pleural fluids taken from patients suffering from lung cancer and treated with intrapleural talc instillation to induce pleurodesis. Furthermore, we have analysed the variations of some inflammatory mediators (C-reactive protein, alpha-1 antitrypsin) and of a protein (plasminogen) involved in MMP activation. In all patients the clinical improvement after talc pleurodesis was followed by a reduction in MMP-1, TIMP-1, C-reactive protein, alpha-1 antitrypsin and plasminogen activity. Furthermore, MMP-9 levels were variable; in fact, in some patients they were high at the beginning of treatment, in others they increased a few days after pleurodesis induction. These inhibitory effects of talc on MMP-1 and inflammatory mediators associated with the reduction of pleural effusion could constitute an effective means to evaluate the evolution of the treatment.

Efeito da derivação pleuroperitoneal no tratamento de hidrotórax recorrente induzido: pleurodese em coelhos

OBJETIVO: Verificar a pleurodese, através da histologia hematoxilina - eosina e microscopia eletrônica, obtida após injeção de tetraciclina, em coelhos com uso de derivação pleuroperitoneal no tratamento de hidrotórax recorrente induzido. MÉTODOS: Foram utilizados 30 coelhos New - Zealand, machos e adultos. Empregou-se anestesia dissociativa quetamina e xilazina em injeção intramuscular 0,1 cm³ para cada 100g de peso do animal. Para induzir hidrotórax utilizou-se tetraciclina 7 mg/kg, diluída em 10 cm³ de água destilada (pH 4) injetada via percutânea no 4º espaço intercostal anterior esquerdo. O ato operatório constituiu de laparotomia subcostal à esquerda com 4 cm de extensão e incisão do hemidiafragma na porção muscular de 0,5 cm de diâmetro. No grupo A (controle) realizou-se fechamento da abertura do diafragma com pontos simples e fio monofilamentar 5.0. No grupo B (derivação) após abertura do diafragma introduziu-se prótese cilíndrica com 2 cm de comprimento. No grupo C (drenagem) foi feita uma laparotomia subcostal esquerda com 2 cm de extensão e introdução de cateter nº 6. Toracotomia lateral esquerda com 2 cm de extensão e descolamento hipodérmico para aplicação do cateter pleurointercostodermoperitoneal. No pós-operatório realizou-se indução de hidrotórax repetida no 1º, 5º, 8º e 12º dia de pós-operatório nos três grupos de estudo através de injeção intrapleural de tetraciclina 7 mg/kg (pH 4) no 4º espaço intercostal anterior esquerdo. Foi feita eutanasia no 15º dia e necropsia para retirada de líquido pleural e histologia pleural, pulmonar e peritônio parietal. RESULTADOS: O acúmulo de líquido pleural resultante foi mais significante nos animais do grupo A. A irritação química resultou no espessamento pleural moderado nos grupos B e C. O índice de pleurodese foi 100% do grupo derivação pleuroperitoneal e 80% do grupo drenagem. CONCLUSÃO: A derivação pleuroperitoneal facilita a formação de pleurodese comprovada histologicamente, mesmo com a utilização de dose baixa de tetraciclina em coelhos.

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.

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.

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.

Experimental Pleurodesis in Rabbits Induced by Silver Nitrate or Talc

STUDY OBJECTIVE

To compare the pleurodesis results from the intrapleural injection of silver nitrate and talc slurry over an observation period of 12 months in rabbits.

DESIGN

Rabbits were randomized to receive 2 mL of 0.5% silver nitrate or 400 mg/kg of talc slurry in 2 mL intrapleurally. Ten rabbits in each group were killed at 1 month, 2 months, 4 months, 6 months, 8 months, 10 months, and 12 months after intrapleural injection. The degree of gross pleurodesis and the amount of microscopic pleural fibrosis and inflammation were graded on a scale of 0 to 4.

RESULTS

The mean +/- SEM gross pleurodesis score in the 70 rabbits that received silver nitrate was 3.34 +/- 0.08, which was significantly higher than the score of 2.32 +/- 0.09 in the 70 rabbits that received talc. The mean gross pleurodesis score was significantly higher at each of the observation times (p < 0.05), except at 2 months, in the rabbits that received silver nitrate. The pleurodesis was distributed throughout the thorax in the rabbits that received silver nitrate, while it was only in the ventral thorax in the rabbits that received talc slurry. The gross pleurodesis scores showed no tendency to decrease during the 12-month observation period in either treatment group. The persistence of talc in the pleural space did not lead to chronic inflammatory changes because the inflammation scores were similar in both groups at all observation times. The microscopic pleural fibrosis score tended to decrease with time in the silver nitrate group but not in the talc slurry group.

CONCLUSIONS

The intrapleural injection of 2 mL of 0.5% silver nitrate produces a better pleurodesis than does the intrapleural injection of 400 mg/kg of talc slurry in rabbits. The pleurodesis induced by silver nitrate persists for at least 1 year. The efficacy of silver nitrate as a sclerosing agent in humans should be evaluated.

Transforming growth factor-beta2 induces pleurodesis significantly faster than talc

Transforming growth factor-beta2 (TGF-beta2) has recently been shown to produce effective pleurodesis in rabbits. Conventional pleurodesing agents such as talc act by inducing pleural injury, which results in acute inflammation and fibrosis. TGF-beta2 is a profibrotic cytokine capable of producing fibrosis without inducing significant pleural inflammation. We hypothesize that intrapleural administration of TGF-beta2 would (1) produce an effective pleurodesis faster; (2) stimulate more collagen deposition, and (3) induce less inflammation when compared with intrapleural injection of talc. Thirty rabbits were divided into two groups and given either TGF-beta(2) (1.7 microg) or talc slurry (400 mg/kg) via a chest tube. Five rabbits from each group were killed at Days 1, 4, and 7. Gross pleurodesis was graded from 1 (none) to 8 (complete symphysis). The microscopic pleural inflammation and fibrosis were graded from 0 to 4. Pleural thickening and the total area of collagen deposition were compared. Intrapleural injection of TGF-beta2 produced effective pleurodesis within 7 d (median pleurodesis score = 7 at Day 7). At Day 7, TGF-beta2 induced significantly more collagen deposition (19.4 +/- 19.6% versus 4.6 +/- 2.9% of total area of pleura at Day 7), higher pleural fibrosis score (3.0 +/- 1.0 versus 1.8 +/- 0.5), and pleural thickness (286 +/- 191 versus 85 +/- 37 microm) than did talc. There was no difference in the degree of pleural inflammation between the two groups at Day 7 (2.6 +/- 0.9 for TGF-beta2 versus 2.4 +/- 0.6 for talc) or at any other time points. In conclusion, the intrapleural administration of TGF-beta2 produced excellent pleurodesis in rabbits at a rate faster than talc slurry and all other pleurodesing agents investigated before. TGF-beta2 stimulated more collagen deposition without inducing excess inflammation when compared with talc slurry. TGF-beta2 may have advantages over talc slurry in the management of recurrent pleural effusion and pneumothorax.