Tetracycline and doxycycline inhibit pleural fluid metalloproteinases. A possible mechanism for chemical pleurodesis

Recurrence of symptoms may indicate the presence of a Morel-Lavallée lesion of the knee: A case report and literature review

Case

An 81 year old male with four failed aspirations presented with recurrent knee swelling following irrigation and debridement, which suggested the presence of a Morel-Lavallée lesion (MLL). This diagnosis was intraoperatively confirmed by separation of the tissue layers forming a space with accumulated fluid. Treatment consisted of doxycycline sclerodesis and tight closure of the tissue layers. The patient had a satisfactory outcome at 4 months.

Conclusion

Resolution of Morel-Lavallée lesions requires prompt recognition and appropriate treatment. In the presence of a different diagnosis, recurrence of symptoms following treatment may indicate an MLL. Surgical treatment with doxycycline sclerodesis resulted in resolution of symptoms.

Drug Eluting Embolization Particles for Permanent Contraception

Medical technology that blocks the fallopian tubes nonsurgically could increase access to permanent contraception and address current unmet needs in family planning. To achieve total occlusion of the fallopian tube via scar tissue formation, acute trauma to the tubal epithelium must first occur followed by a sustained and ultimately fibrotic inflammatory response. Here, we developed drug-eluting fiber-based microparticles that provide tunable dose and release of potent sclerosing agents. This fabrication strategy demonstrates high encapsulation of physicochemically diverse agents and the potential for scalable manufacturing by utilizing free-surface electrospinning to generate material for fiber micronization. Manipulation of nanofiber formulation such as drug loading, drug hydrophobicity, polymer hydrophobicity, and crystallinity allowed for modulation of the sustained release properties of our fiber microparticles. We assessed various fibrous microparticle formulations in vivo using a newly developed and validated guinea pig model for contraception. We found that fiber microparticles with bolus release doxycycline effectively elicited acute trauma and those formulated with highly loaded phenyl benzoate caused sustained inflammation in the target organs. The demonstrated potency of these electrospun microparticles, as well as their embolic size and shape, suggests potential for proximal agglomeration and inflammatory activity in the fallopian tubes following transcervical delivery.

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.

Comparisons of doxycycline solution with talc slurry for chemical pleurodesis and risk factors for recurrence in South Korean patients with spontaneous pneumothorax

Purpose

Talc slurry (TS) has been commonly used with high success rates in managing spontaneous pneumothroax (SP), but there were concerns of post-procedural complications. Alternatively, doxycycline solution (DS) was used successfully. This retrospective study aims to compare the effectiveness and safety between talc and doxycycline as a sclerosing agent and to investigate risk factors for recurrence in patients with SP.

Methods

The review of medical records between January 2011 and December 2014 was conducted on 83 patients with SP who underwent pleurodesis with either TS (n=16) or DS (n=67). Recurrence and complications were compared between the DS and TS groups. Associations between recurrence after DS treatment and various factors were analysed.

Results

Recurrence was significantly higher in the DS group than in the TS group (P=0.033), whereas complications were higher in the TS group than the DS group: fever was significantly higher in the TS group (P=0.001). Recurrences associated with doxycycline use were found significantly more often in patients with recurrent diagnosis of SP, height/weight ≥3.25 cm/kg and weight <55 kg.

Conclusion

Talc was more effective without recurrence compared with doxycycline. Clinically insignificant fever associated with pleurodesis was more common with talc. Low weight, high height to weight ratio and recurrent diagnosis of SP were associated with higher recurrence after doxycycline treatment.

Chemical Pleurodesis Using Mistletoe Extraction (ABNOVAviscum(®) Injection) for Malignant Pleural Effusion

PURPOSE

Malignant pleural effusion (MPE) is common in patients with advanced cancer. Chemical pleurodesis can be considered for MPE that do not respond to chemotherapy, radiotherapy, or therapeutic thoracentesis. However, it is not yet clear which agent is more effective and safer in chemical pleurodesis.

METHODS

This study was designed as a single arm, multicenter, and open-label phase III clinical trial to evaluate efficacy and safety of chemical pleurodesis using mistletoe extraction (ABNOVAviscum(®) Injection). References of other agents in chemical pleurodesis were investigated to compare efficacy and safety. Efficacy was evaluated by followed up chest X-ray and changes of clinical symptoms and Karnofsky performance scale. Safety was evaluated by serious adverse event (SAE) and changes of laboratory findings. A follow-up period was 4 weeks after last pleurodesis.

RESULTS

Of 62 patients, 49 (79.0%) had complete response, 11 (17.7%) had partial response, and two had no response. Mean response rate was significantly different in this study comparing with reference response rate which was 64% (p <0.0001). There were two SAEs, but all were recovered without sequelas.

CONCLUSION

The results of this study suggest that mistletoe extraction (ABNOVAviscum(®) Injection) could be an effective and safe agent of chemical pleurodesis in patients with MPE.

Fisetin inhibits matrix metalloproteinases and reduces tumor cell invasiveness and endothelial cell tube formation

Matrix metalloproteinases (MMPs) play an important role in tissue remodeling during normal physiological situations and pathological implications such as tumor invasion and metastasis. MMP inhibitors were screened from extracts of medicinal herbs by an enzymatic assay using the MMP-14 catalytic domain. Among samples tested, a methanol extract of the root of Dalbergia odorifera T. CHEN (Leguminosae) showed the strongest inhibitory activity. The inhibitory component was purified through fractionation methods and identified as fisetin, abundant in many fruits and vegetables. In addition to inhibition of MMP-14, fisetin inhibits MMP-1, MMP-3, MMP-7, and MMP-9, more efficiently than a naturally occurring MMP inhibitor tetracycline. Fisetin dose-dependently inhibits proliferation of fibrosarcoma HT-1080 cells and human umbilical vascular endothelial cells (HUVECs), MMP-14-mediated activation of proMMP-2 in HT-1080 cells, invasiveness of HT-1080 cells, and in vitro tube formation of HUVECs. Therefore, fisetin could be valuable as a chemopreventive agent against cancer and a lead compound for development of therapeutic MMP inhibitors.

Efficacy of tigecycline pleurodesis: a comparative experimental study

BACKGROUND

We investigated whether tigecycline (TIGE) is more effective than talc in inducing pleurodesis in rabbits.

METHODS

Fifty-six New Zealand rabbits were utilized in a two-phase study: Effects at 14 d (phase I) and at 28 d (phase II) were assessed. Saline solution (SAL n = 3), talc slurry (TALC 200 mg/kg, n = 5), and TIGE at different concentrations (mg/kg): TIGE0.5 (n = 5); TIGE1 (n = 5); TIGE3 (n = 5); TIGE25 (n = 5); TIGE50 (n = 5) were randomly injected, for each phase, through a right chest drainage. TIGE0.5 and TIGE1 were ineffective during phase I and were thus excluded from further investigation. At post mortem examination, pleurodesis was graded grossly and microscopically by three observers blinded to treatment groups.

RESULTS

Phase I: pleurodesis was more effective in TIGE25 and TIGE50 (P < 0.001); TALC was better than TIGE0.5 (P < 0.001), and TIGE1 (P = 0.49), macroscopically. Pleural thickness was significantly higher in TIGE25 compared with SAL, TALC, TIGE0.5, TIGE1, and TIGE3 (P < 0.01). No significant differences were evident between TALC and TIGE3, both macroscopically (P = 0.90) and microscopically (inflammation P = 0.99, fibrosis P = 0.96, pleural thickness P = 0.99). Phase II: better effectiveness of TIGE50 compared with all other groups (P < 0.001) except TIGE 25 (P = 0.29); results similar to phase I for TALC and TIGE3 (P = 0.99), macroscopically. Microscopically greater inflammation in TALC compared with TIGE3 (P < 0.05) and in TIGE50 to TIGE3 (P = 0.05). Significant complications occurred in all TIGE50 group. One of TIGE25 and one of TIGE50 died of respiratory distress and of right hemothorax+ascites, respectively.

CONCLUSIONS

Intrapleural TIGE3 mg/kg is as effective as talc in inducing pleurodesis in rabbits. The intrapleural TIGE toxicity threshold was reached at TIGE25 mg/kg concentration.

Penitentiary or penthouse condo: the tuberculous granuloma from the microbe's point of view

Granuloma formation represents a pivotal point during human infection with Mycobacterium tuberculosis, for this structure may limit mycobacterial spread and prevent active disease, while at the same time allow for the survival and persistence of viable mycobacteria within the host. The current therapeutic regimens for treating tuberculosis disease have proven effective in developing countries. However, in countries with large populations, limited access to health care, and high incidence of HIV co-infection, tuberculosis disease continues to represent a major global health emergency. Particularly, the emergence of extensively and multi-drug-resistant forms of tuberculosis underscores the need develop new treatment strategies. Recent mechanistic studies have identified bacterial virulence mechanisms that subvert host responses and lead to an inappropriate upregulation of host factors such as tumour necrosis factor-alpha (TNF-alpha) and matrix metalloproteinases (MMPs). Paradoxically, then, part of the mycobacterial virulence programme may be to promote granuloma development and maturation. These observations suggest that together with appropriate anti-microbials host-based therapeutics directed at TNF-alpha and MMP inhibition may counteract the microbial subterfuge, reduce the pro-granulomatous response, and offer an enhanced therapeutic effect. Host-directed therapy that alters the immune response may offer an alternative approach towards reducing treatment duration, the risk of anti-microbial resistance and improving patient outcome.

Doxycycline reduces mortality and injury to the brain and cochlea in experimental pneumococcal meningitis

Bacterial meningitis is characterized by an inflammatory reaction to the invading pathogens that can ultimately lead to sensorineural hearing loss, permanent brain injury, or death. The matrix metalloproteinases (MMPs) and tumor necrosis factor alpha-converting enzyme (TACE) are key mediators that promote inflammation, blood-brain barrier disruption, and brain injury in bacterial meningitis. Doxycycline is a clinically used antibiotic with anti-inflammatory effects that lead to reduced cytokine release and the inhibition of MMPs. Here, doxycycline inhibited TACE with a 50% inhibitory dose of 74 microM in vitro and reduced the amount of tumor necrosis factor alpha released into the cerebrospinal fluid by 90% in vivo. In an infant rat model of pneumococcal meningitis, a single dose of doxycycline (30 mg/kg) given as adjuvant therapy in addition to ceftriaxone 18 h after infection significantly reduced the mortality, the blood-brain barrier disruption, and the extent of cortical brain injury. Adjuvant doxycycline (30 mg/kg given subcutaneously once daily for 4 days) also attenuated hearing loss, as assessed by auditory brainstem response audiometry, and neuronal death in the cochlear spiral ganglion at 3 weeks after infection. Thus, doxycycline, probably as a result of its anti-inflammatory properties, had broad beneficial effects in the brain and the cochlea and improved survival in this model of pneumococcal meningitis in infant rats.

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.

Pleurodesis is inhibited by anti-vascular endothelial growth factor antibody

STUDY OBJECTIVES

The intrapleural injection of transforming growth factor (TGF)-beta2 produces pleurodesis in rabbits associated with large pleural effusions. This study investigated whether anti-vascular endothelial growth factor (VEGF) antibody has any effect on the fluid production or the pleurodesis induced by TGF-beta2.

INTERVENTIONS AND MEASUREMENTS

Three groups of seven New Zealand white rabbits were administered TGF-beta2 5.0 microg intrapleurally. Two groups received anti-VEGF antibody (10 mg/kg and 25 mg/kg) IV 24 h before TGF-beta2 injection, and the third group received no antibody. The rabbits were killed at 2 weeks, and the macroscopic pleurodesis score was determined. The degree of pleural angiogenesis was assessed by immunohistochemical staining for factor VIII.

RESULTS

The administration of anti-VEGF antibodies had no significant effect on the pleural fluid volume or the characteristics of the fluid. The mean pleurodesis score of the seven rabbits in the control group (7.71 +/- 0.76) was significantly (p < 0.05) higher than that for seven rabbits in the low-dose treatment group (4.43 +/- 2.37) and the seven rabbits in the high-dose treatment group (4.57 +/- 2.36) [+/- ]. The percentage of pleural tissue demonstrating angiogenesis in the control group (4.87 +/- 0.43%) was significantly (p < 0.05) higher than that for the low-dose (2.94 +/- 0.68%) or high-dose (2.67 +/- 0.64%) antibody groups. When all rabbits were considered, there was a highly significant correlation between the pleural vascular density scores and the pleurodesis scores (r = 0.84, p < 0.01).

CONCLUSION

VEGF and angiogenesis appear to play a pivotal role in the production of a pleurodesis.

Expression of matrix metalloproteinase-9 in pleural effusions of tuberculosis and lung cancer

BACKGROUND

Matrix metalloproteinase (MMP)-9 has been implicated in the development of pleural effusions.

OBJECTIVES

The aim of this study was to assess the expression of MMP-9 in pleural effusions of tuberculosis, lung cancer and transudates.

METHODS

Ninety-one patients (37 tuberculous pleural effusions, 42 malignant pleural effusions of lung cancer and 12 transudates) were included. Concentrations of pleural fluid MMP-9 and tissue inhibitors of matrix metalloproteinase (TIMP)-1 were determined by immunoassay. We also investigated the cellular localization of MMP-9 and TIMP-1 by reverse-transcriptase polymerase chain reaction on lymphocytes from pleural effusions and by immunohistochemical analysis of pleural tissues.

RESULTS

Pleural fluid MMP-9 levels, MMP-9/total protein and MMP-9/TIMP-1 ratios were significantly higher in tuberculous pleural effusions, whilst TIMP-1 levels were similar in the three groups. MMP-9 levels positively correlated with TIMP-1 and lactate dehydrogenase levels, and negatively with pH and glucose levels in pleural effusions. MMP-9 mRNA expression in lymphocytes tended to be higher in malignant pleural effusions of lung cancer than in the other groups without reaching statistical significance. The strongest immunoreactivity for MMP-9 was observed in epithelioid cells of tuberculous pleural tissues. Much lower levels of MMP-9 expression were found in tumor cells of pleural tissues.

CONCLUSIONS

MMP-9 is increased in tuberculous pleural effusions compared with transudates and malignant pleural effusions of lung cancer and is produced predominantly by epithelioid cells in the granulomas of tuberculous pleural tissues.

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.

Doxycycline in the Management of Pseudomonas Corneal Melting

BACKGROUND

Pseudomonas keratitis can result in the breakdown of collagen with subsequent corneal melting and perforation. The use of antimetalloproteinases may help to stabilize melting and prevent imminent perforation of the cornea. The use of topical protease inhibitors and neutrophil inhibitors is of limited value. Tetracyclines, however, have been shown to have anticollagenolytic activity and inhibit metalloproteinases, and they may suppress connective tissue breakdown.

PURPOSE

To establish the stabilization of corneal melting in cases of Pseudomonas keratitis.

METHODS

Two young patients with severe contact lens-associated Pseudomonas keratitis and corneal melting were treated with oral doxycycline and standard topical treatment.

RESULTS

Corneal melting was stabilized in each patient, and perforation was avoided.

CONCLUSIONS

Tetracyclines have an anticollagenolytic action in addition to their antimicrobial activity. The use of doxycycline as an adjunctive therapy in the management of Pseudomonas corneal melting may help to stabilize corneal breakdown and prevent subsequent perforation.

Occurrence of matrix metalloproteinases and tissue inhibitors of metalloproteinases in tuberculous pleuritis

OBJECTIVE

Matrix metalloproteinases (MMP) and tissue inhibitors of metalloproteinases (TIMP) have been found in high concentrations in pleural effusions. Because MMP and TIMP may play a part in the causation of the fibrosis seen in tuberculous (TB) pleuritis their occurrence was examined.

DESIGN

Pleural effusion fluid and plasma concentrations of MMP-1, MMP-2, MMP-3, MMP-8, MMP-9, TIMP-1 and TIMP-2 were determined by ELISA in 21 patients with TB pleuritis. To adjust for the total protein content, respective ratios were calculated. Activities of MMP-2 and MMP-9 were measured by gelatine zymography and the MMP-9/MMP-2 ratios calculated. Pleural effusions and plasma of 15 patients with congestive heat failure (CHF) and plasma of 15 healthy persons (CON) served as controls.

RESULTS

Immunoreactive pleural fluid concentrations of MMP-1, MMP-2, MMP-8, and MMP-9 were higher in TB compared to CHF, but plasma concentrations were not different between the groups. TB pleural fluid concentrations of MMP-1, MMP-2, TIMP-1, and TIMP-2 were higher compared to TB plasma. MMP-3 was found in trace amounts only. The MMP-9/total protein ratios in pleural fluid were higher in TB compared to CHF (0.4492+/-0.1633 vs 0.0364+/-0.0145, P<0.005) but the TIMP-1 ratios were lower (139.0+/-28.7 vs 517.8+/-183.7, P<0.0005). In TB pleural fluid vs TB plasma, the respective MMP-1, MMP-2, TIMP-1, and TIMP-2 ratios were increased (0.46+/-0.10 vs 0.17+/-0.02; 25.2+/-2.8 vs 4.2+/-0.9; 139.0+/-28.7 vs 27.8+/-8.2; 0.67+/-0.13 vs 0.18+/-0.04, P<0.0005 each). Gelatine zymography demonstrated MMP-2 and MMP-9 bands of different brightness in TB effusions but in CHF effusions the MMP-9 band was barely visible. The MMP-9/MMP-2 effusion ratios were therefore higher in TB compared to CHF (0.46+/-0.15 vs 0.05+/-0.04, P<0.0005).

CONCLUSION

Compartmentalized MMP-1, MMP-2, TIMP-1, and TIMP-2 and, compared to CHF, a surplus of MMP-1, MMP-2, MMP-8, and MMP-9 in the pleural space obviously contribute to the fibrotic reactions in TB pleuritis.

The acute effect of minocycline on the pericardium: experimental and clinical findings

STUDY OBJECTIVES

To evaluate the acute effect of minocycline on the pericardium in the experimental animal and in the human with malignant pericardial disease.

DESIGN

A prospective study in open-chest dogs and in humans.

SETTING

Experimental surgery laboratory, medical school; coronary care unit, university hospital.

METHODS

Twenty-three open-chest dogs were divided into four groups according to the solution injected intrapericardially: (1) minocycline, 5 mg/kg; (2) minocycline, 10 mg/kg; (3) normal saline solution, 100 mL, followed by minocycline, 10 mg/kg; (4) a mixture of 50 mL of the dog's own blood mixed ex vivo with minocycline, 10 mg/kg to evaluate the effect of rising pH of minocycline solution. The extent of myocardial injury is evaluated by measuring ST-T segment deviation in six standard bipolar leads and in three unipolar electrograms recorded over the left ventricular pericardial surface. The pH of the various minocycline solutions is measured. Nine consecutive patients with malignant cardiac tamponade receiving minocycline intrapericardially are evaluated for the appearance of chest pain and ECG changes.

RESULTS

Minocycline (5 and 10 mg/kg) caused marked, transient ST-T segment deviation in all dogs, whether or not saline solution was previously injected into the pericardial sac. Prior mixing of minocycline with blood markedly increased the acidic pH of the minocycline solution and significantly reduced the extent of ST-T segment deviation. Four of nine patients had chest pain during minocycline injection. None had ST-T segment changes.

CONCLUSION

Minocycline causes a marked, transient injury to the epicardial-pericardial surface. Our animal and in vitro studies indicate that this acute injury is probably partly related to the acidic pH of the minocycline solution. Our experimental findings suggest that this minocycline-induced injury may be reduced by raising the pH of the solution either ex vivo (eg, by mixing minocycline with previously withdrawn pericardial fluid) or in vivo (eg, by leaving 200 to 300 mL of pericardial fluid prior to minocycline injection). Limited experience in the human with malignant cardiac tamponade indicates that intrapericardial minocycline is usually well tolerated, although severe chest pain may appear.

MMP and TIMP expression pattern in pleural effusions of different origins

The matrix metalloproteinases (MMP) are proteolytic enzymes that are essentially involved in the turnover of the extracellular matrix (ECM). Their activity is counterbalanced by specific antagonists, the tissue inhibitors of metalloproteinases (TIMP). In this study, we sought to analyze the expression of MMP and TIMP isoforms in pleural effusions from 88 patients. We compared MMP and TIMP isoform expression in transudates (n = 21) and exudates (n = 67), the latter divided into exudates of paraneoplastic (n = 46) or parainfectious (n = 21) origin. Zymographic and Western blot analyses revealed constant expression of interstitial collagenase (MMP-1), gelatinase-A (MMP-2), and TIMP-1 in all 88 samples. In contrast, analyses of gelatinase-B (MMP-9) demonstrated a specific expression pattern, with high expression in exudates and lack of expression in transudates. Neutrophil collagenase (MMP-8) was detected in trace amounts, and correlated with the number of neutrophils in the effusion. Low levels of TIMP-2 were detected only in exudates and not in transudates. Quantitative analysis of the expression ratio of gelatinase-B to gelatinase-A revealed statistically significant differences between effusions of different origin. The ratio was highest in exudates of paraneoplastic origin and lowest in transudates. Our data thus suggest that interstitial collagenase, gelatinase-A, and TIMP-1 play a role in homeostasis of the pleural space in vivo as constitutively expressed proteins, whereas gelatinase-B and TIMP-2 expression are induced in specific disease states. These observations contribute to the understanding of the pathophysiology of pleural effusions, and may help to characterize and possibly distinguish effusions of different origin.

The efficacy of doxycycline as a pleural sclerosing agent in malignant pleural effusion: a prospective study

To determine the efficacy of doxycycline in producing pleuroedesis in patients with malignant pleural effusion (MPE), 31 documented cases of MPE, aged 19-82 years were prospectively studied. Pleural sclerosis was done with 500 mg of doxycycline. Response regarding respiratory symptoms and pleural fluid accumulation were evaluated monthly. At one month, 27 patients were evaluable (4 dropped out). All responded and required no therapeutic thoracentesis. At 3 months, 13 patients dropped out, only 14 patients were evaluable. It revealed that 13 out of 14 patients (92%) responded. Only one patient failed and required therapeutic thoracentesis. Five and two patients came for assessment at 6 and 12 months, respectively. They still benefited from doxycycline pleurodesis. Side effects including low grade fever in 30% of patients, moderate to severe pain in 60% and troublesome cough with hemoptysis in one patient (3%) were noted. Doxycycline is an effective agent in controlling MPE. It was successful in every patient at 1 month and in 92% at 3 months. At 6 and 12 months quite a few patients survived for evaluation. However, they still benefited from doxycycline pleurodesis. Side effects were tolerable.

Phase I trial of a novel matrix metalloproteinase inhibitor batimastat (BB-94) in patients with advanced cancer

Degradation of basement membrane and extracellular matrix by matrix metalloproteinases (MMPs) is believed to be required for tumor invasion, tumor-induced angiogenesis and vascular invasion. A synthetic hydroxamate, batimastat (also known as BB-94), inhibits MMPs by binding the zinc ion in the active site of the MMP. Batimastat inhibits at least 50% of MMP activity at concentrations less than or equal to 10 ng/ml in vitro. Batimastat retarded ascites accumulation and increased survival in mice with human ovarian tumor xenografts. Acute and long-term toxicological studies revealed no major toxicity in animals. Batimastat is poorly soluble and was administered intraperitoneally (i.p.) as a suspension. Previous studies in patients with malignant ascites have shown no major toxicities at doses as high as 1350 mg/m2.

Human neutrophil collagenase (MMP-8), identified in bronchiectasis BAL fluid, correlates with severity of disease

Collagenases in bronchoalveolar lavage fluid (BALF) of patients with bronchiectasis and healthy subjects were characterized using specific functional and immunologic assays. The BAL fluid contained interstitial collagenase and collagenolytic proteinases of bacterial origin. Collagenase activities, obtained after organomercurial activation, correlated with the severity of bronchiectasis. In severe cases, collagenase activities were 3.5 x 10(-7) IU/L/48 h or 4.8 x 10(-6) IU/g/48 h (p < 0.01), in moderate ones 1.74 x 10(-7) IU/L/48 h or 3.35 x 10(-6) IU/g/48 h (p < 0.05), and in mild cases 0.32 x 10(-7) IU/L/48 h or 0.7 x 10(-6) IU/g/48 h (p < 0.05). The corresponding activities in healthy control subjects were 0.08 x 10(-7) IU/L/48 h or 0.13 x 10(-6) IU/g/48 h. The cellular origin of interstitial collagenase was assessed with doxycycline inhibition test utilizing the differential sensitivity of fibroblast-type collagenase/MMP-1 (IC50 = 280 microM) and neutrophil-type collagenase/MMP-8 (IC50 = 26 microM) to the anticollagenolytic, nonantimicrobial doxycycline action. Interstitial collagenase, contained in BALF, was totally inhibited by 100 microM of doxycycline. It can therefore be concluded that most of mammalian collagenase presented in inflamed fluid of bronchiectasis originated from neutrophils. The molecular forms of neutrophil-type collagenase/MMP-8 were confirmed and analyzed by Western-blot, which showed evidence of the proteolytic conversion of the latent 85-kD MMP-8 proenzyme species into active 65-kD molecular weight species. These findings strongly suggest involvement of proteolytic activation pathway of proMMP-8, especially in severe and moderate forms of bronchiectasis. Furthermore, collagenolytic proteases of bacterial origins may also participate in tissue destruction of the lung.

Pleurodesis with doxycycline or Corynebacterium parvum in malignant pleural effusion

Pleurodesis with doxycycline (100 mg and 600 mg) and Corynebacterium parvum (1 mg and 7 mg) were compared in 41 patients with malignant effusion. To evaluate the mechanisms, pleural fluid pH, leukocytes, granulocytes, interleukin-6 (IL-6) and serum IL-6, as well as C-reactive protein (CRP) were measured before and on 2 consecutive days after treatment. Corynebacterium parvum produced a greater acute-phase response measured with fever, serum CRP and IL-6 than doxycycline. However, no change in pleural fluid IL-6 was demonstrated. Among the 35 assessed patients, 26 had objective response, similar in all four treatment groups. Side-effects were more common with Corynebacterium parvum. Based on this preliminary study we conclude that doxycycline, even in low doses, is a highly effective and well tolerated agent for palliative treatment of malignant pleural effusion. As the responses were similar despite different inflammatory reactions, the two agents probably induce pleural obliteration through different mechanisms.

Histologic changes of doxycycline pleurodesis in rabbits. Effect of concentration and pH

The effects of doxycycline hyclate (DOXY) pleurodesis were compared with those of tetracycline hydrochloride (TCN) in 25 healthy New Zealand White rabbits. One group of rabbits received TCN (pH 2.0) in the left pleural space at a concentration of 35 mg/kg in 3.0 ml of saline solution. Four other groups of rabbits received DOXY in two concentrations (35 mg/kg or 10 mg/kg) and at two pHs (an acid of 2.0 and a NaOH neutralized pH of 7.6). No attempt was made to drain the pleural space after pleurodesis. At autopsy 2 weeks later, bloody fluid filled the pleural cavity and extensive intrapleural adhesions compressed the underlying lung. Microscopically, fibrin and collagen were diffusely deposited in the pleural connective tissue and in the intrapleural adhesions. The visceral pleural thickness increased from its normal value of 0.01 mm to values of 0.5 to 0.9 mm in the TCN and DOXY groups. Fibroblasts were the predominant inflammatory cell in the pleural connective tissue with few neutrophils or lymphocytes. No significant differences of histologic characteristics were observed between the TCN and DOXY groups. Alterations in pH or concentration in the DOXY groups produced similar changes in the gross and microscopic appearance of the pleural space. We conclude that DOXY is as effective as TCN in producing chemical pleurodesis. Doxycycline concentrations of 10 mg/kg were sufficient to substantially sclerose the pleural space in these healthy rabbits. Doxycycline pleurodesis was effective at neutral pH suggesting a mechanism of action independent of acid injury to the mesothelium.

Matrix metalloproteases and lung disease

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Clinical efficacy of doxycycline for pleurodesis

To determine the efficacy of doxycycline as a pleural sclerosing agent, we examined the outcomes in 31 patients (aged 31 to 87 years) receiving doxycycline (500 to 1,000 mg) through a chest tube for malignant pleural effusions or persistent bronchopleural fistulae. Of the 27 patients with malignant pleural effusions, 21 patients had a complete short-term response (no fluid reaccumulation during the initial hospitalization); 5 of the 6 short-term nonresponders had partial control of effusions, with improvement in respiratory symptoms. Of the 23 patients who survived longer than 1 month, 15 patients did not have reaccumulation of fluid during follow-up. All four patients with persistent bronchopleural fistulae had resolution of their air leaks; one patient had recurrence with a partial pneumothorax. Pleural pain controllable with narcotic therapy was the only important complication. Thus, doxycycline is a suitable substitute for tetracycline as a pleural sclerosing agent.