Basic fibroblast growth factor and its receptors in idiopathic pulmonary fibrosis and lymphangioleiomyomatosis

Nintedanib (BIBF 1120) for IPF: a tomorrow therapy?

Idiopathic pulmonary fibrosis is a rare, life threatening disease characterized by an anarchic fibrogenesis, limited survival and few therapeutic options. Its pathogenesis is complex and involves the interaction among various pathways driven by proinflammatory/profibrogenetic mediators such as platelet -derived growth factor, vascular endothelial growth factor or basic fibroblast growth factor. Given their prominent pathogenic roles in this disease such growth factor might be suitable therapeutic targets.In fact, the existing preclinical and clinical data demonstrated that their therapeutic inhibition results in a delayed progression of the pulmonary fibrosis and in the improvement of the disease outcome. BIBF 1120 is a potent triple blocker of the receptors of these growth factors which is currently evaluated as a potential therapy in the idiopathic pulmonary fibrosis. This review discusses the existing data supporting its potential use in this disease.

Mesenchymal stem cell-conditioned media recovers lung fibroblasts from cigarette smoke-induced damage

Cigarette smoking causes apoptotic death, senescence, and impairment of repair functions in lung fibroblasts, which maintain the integrity of alveolar structure by producing extracellular matrix (ECM) proteins. Therefore, recovery of lung fibroblasts from cigarette smoke-induced damage may be crucial in regeneration of emphysematous lung resulting from degradation of ECM proteins and subsequent loss of alveolar cells. Recently, we reported that bone marrow-derived mesenchymal stem cell-conditioned media (MSC-CM) led to angiogenesis and regeneration of lung damaged by cigarette smoke. In this study, to further investigate reparative mechanisms for MSC-CM-mediated lung repair, we attempted to determine whether MSC-CM can recover lung fibroblasts from cigarette smoke-induced damage. In lung fibroblasts exposed to cigarette smoke extract (CSE), MSC-CM, not only inhibited apoptotic death, but also induced cell proliferation and reversed CSE-induced changes in the levels of caspase-3, p53, p21, p27, Akt, and p-Akt. MSC-CM also restored expression of ECM proteins and collagen gel contraction while suppressing CSE-induced expression of cyclooxygenase-2 and microsomal PGE(2) synthase-2. The CSE-opposing effects of MSC-CM on cell fate, expression of ECM proteins, and collagen gel contraction were partially inhibited by LY294002, a phosphatidylinositol 3-kinase (PI3K) inhibitor. In rats, MSC-CM administration also resulted in elevation of p-Akt and restored proliferation of lung fibroblasts, which was suppressed by exposure to cigarette smoke. Taken together, these data suggest that MSC-CM may recover lung fibroblasts from cigarette smoke-induced damage, possibly through inhibition of apoptosis, induction of proliferation, and restoration of lung fibroblast repair function, which are mediated in part by the PI3K/Akt pathway.

Lung mast cell density defines a subpopulation of patients with idiopathic pulmonary fibrosis

AIMS

The relationship of mast cells to the pathogenesis of lung fibrosis remains undefined despite recognition of their presence in the lungs of patients with pulmonary fibrosis. This study was performed to characterize the relationship of mast cells to fibrotic lung diseases.

METHODS AND RESULTS

Lung tissues from patients with idiopathic pulmonary fibrosis (IPF), chronic hypersensitivity pneumonitis (HP), systemic sclerosis (SSc)-related interstitial lung disease (ILD) and normal individuals were subjected to chymase immunostaining and the mast cell density quantified. Eosinophils were quantified by immunostaining for eosinophil peroxidase. Changes in lung function were correlated with mast cell density. Lung tissue obtained from IPF patients had a higher density of chymase-immunoreactive mast cells than that from patients with HP, SSc-related ILD or normal lungs. IPF lung tissue had a higher density of eosinophils than normal lung. There was no correlation between mast cell density and eosinophil density in IPF lung. IPF patients with high mast cell density had a slower rate of decline in forced vital capacity (FVC) than IPF patients with low mast cell density.

CONCLUSIONS

Mast cell density in IPF lungs is higher than in other fibrotic lung diseases and normal lungs. Increased mast cell density in IPF may predict slower disease progression.

Immunoglobulin free light chains are increased in hypersensitivity pneumonitis and idiopathic pulmonary fibrosis

Background

Idiopathic pulmonary fibrosis (IPF), a devastating lung disorder of unknown aetiology, and chronic hypersensitivity pneumonitis (HP), a disease provoked by an immunopathologic reaction to inhaled antigens, are two common interstitial lung diseases with uncertain pathogenic mechanisms. Previously, we have shown in other upper and lower airway diseases that immunoglobulin free light chains (FLCs) are increased and may be involved in initiating a local inflammation. In this study we explored if such a mechanism may also apply to HP and IPF.

Methods

In this study we examined the presence of FLC in serum and BAL fluid from 21 IPF and 22 HP patients and controls. IgG, IgE and tryptase concentrations were measured in BAL fluid only. The presence of FLCs, plasma cells, B cells and mast cells in lung tissue of 3 HP and 3 IPF patients and 1 control was analyzed using immunohistochemistry.

Results

FLC concentrations in serum and BAL fluid were increased in IPF and HP patients as compared to control subjects. IgG concentrations were only increased in HP patients, whereas IgE concentrations were comparable to controls in both patient groups. FLC-positive cells, B cells, plasma cells, and large numbers of activated mast cells were all detected in the lungs of HP and IPF patients, not in control lung.

Conclusion

These results show that FLC concentrations are increased in serum and BAL fluid of IPF and HP patients and that FLCs are present within affected lung tissue. This suggests that FLCs may be involved in mediating pathology in both diseases.

Mast cells in lung inflammation

Mast cells play an important role in the lung in both health and disease. Their primary role is to initiate an appropriate program of inflammation and repair in response to tissue damage initiated by a variety of diverse stimuli. They are important for host immunity against bacterial infection and potentially in the host immune response to non small cell lung cancer. In situations of ongoing tissue damage, the sustained release of numerous pro-inflammatory mediators, proteases and cytokines, contributes to the pathophysiology of lung diseases such as asthma and interstitial lung disease. A key goal is the development of treatments which attenuate adverse mast cell function when administered chronically to humans in vivo. Such therapies may offer a novel approach to the treatment of many life-threatening diseases.

Selected growth factors and diffusing capacity of the lung for carbon monoxide in patients with systemic lupus erythematosus

The purpose of the study was to evaluate serum concentrations of selected growth factors and the diffusing capacity of the lung for carbon monoxide (DLCO) in 21 females treated for systemic lupus erythematosus. The control group consisted of 24 healthy women. Based on the high-resolution computed tomography (HRCT), patients were allocated to a subgroup of 11 subjects (HRCT-negative) and a subgroup of 10 with pulmonary abnormalities (HRCT-positive). In HRCT-negative patients a significantly higher level of TNF-α as compared with the control was observed and positive correlation between TNF-α and bFGF was revealed in this subgroup and in the total group of patients. DLCO was below the predicted value in 13 patients. No correlations between DLCO and growth factors concentrations were observed. DLCO reduction in asymptomatic, with respect to the respiratory system, SLE patients suggests a need for long-term monitoring of this parameter. The role of TNF-α in these patients requires further investigations.

Detection of immunological biomarkers correlated with asthma control and quality of life measurements in sera from chronic asthmatic patients

BACKGROUND

Clinical outcomes of patients with asthma are highly variable. Immunological biomarkers associated with asthma control have not been elucidated.

OBJECTIVE

To identify the association between clinical control of asthma and serum immunological profiles of asthmatics and compare these profiles with those of healthy controls by using a multiplex assay.

METHODS

Sera were obtained from 28 nonsmokers 18 to 55 years of age with moderate and severe persistent asthma. Patients were classified as having well-controlled (WC, n = 14) or poorly controlled (PC, n = 14) asthma based on their responses to the Asthma Control Questionnaire and Asthma Quality of Life Questionnaire. Sera from nonasthmatic control individuals (NAC, n = 14) were used for comparison. Levels of 50 analytes, including cytokines, chemokines, angiogenic, and growth factors, were determined, using a multiplex assay.

RESULTS

Twelve of the 29 cytokines levels were significantly higher in patients with asthma than in NACs, but only interferon gamma levels were significantly lower in patients with asthma than in the NAC group. Among these, interleukin (IL)-3 and IL-18 levels were significantly higher in the PC group than the WC group. Five of the 12 tested chemokine levels were significantly higher in patients with asthma than in NACs. Five of six growth factor levels were significantly higher in patients with asthma than in NACs, and 3 were higher in PC than WC. Interleukin-18, fibroblast growth factor, hepatocyte growth factor, and stem cell growth factor-beta were positively correlated with poor asthma control and negatively with quality of life scores.

CONCLUSIONS

Increased serum levels of fibroblast growth factor, hepatocyte growth factor, and stem cell growth factor-beta might be useful biomarkers of asthma control status and targets of future asthma therapy.

Erythropoietin-driven proliferation of cells with mutations in the tumor suppressor gene TSC2

Lymphangioleiomyomatosis (LAM) is characterized by cystic lung destruction, resulting from proliferation of smooth-muscle-like cells, which have mutations in the tumor suppressor genes TSC1 or TSC2. Among 277 LAM patients, severe disease was associated with hypoxia and elevated red blood cell indexes that accompanied reduced pulmonary function. Because high red cell indexes could result from hypoxemia-induced erythropoietin (EPO) production, and EPO is a smooth muscle cell mitogen, we investigated effects of EPO in human cells with genetic loss of tuberin function, and we found that EPO increased proliferation of human TSC2-/-, but not of TSC2+/-, cells. A discrete population of cells grown from explanted lungs was characterized by the presence of EPO receptor and loss of heterozygosity for TSC2, consistent with EPO involvement. In LAM cells from lung nodules, EPO was localized to the extracellular matrix, supporting evidence for activation of an EPO-driven signaling pathway. Although the high red cell mass of LAM patients could be related to advanced disease, we propose that EPO, synthesized in response to episodic hypoxia, may increase disease progression by enhancing the proliferation of LAM cells.

miR-21 mediates fibrogenic activation of pulmonary fibroblasts and lung fibrosis

Uncontrolled extracellular matrix production by fibroblasts in response to tissue injury contributes to fibrotic diseases, such as idiopathic pulmonary fibrosis (IPF), a progressive and ultimately fatal process that currently has no cure. Although dysregulation of miRNAs is known to be involved in a variety of pathophysiologic processes, the role of miRNAs in fibrotic lung diseases is unclear. In this study, we found up-regulation of miR-21 in the lungs of mice with bleomycin-induced fibrosis and also in the lungs of patients with IPF. Increased miR-21 expression was primarily localized to myofibroblasts. Administration of miR-21 antisense probes diminished the severity of experimental lung fibrosis in mice, even when treatment was started 5-7 d after initiation of pulmonary injury. TGF-beta1, a central pathological mediator of fibrotic diseases, enhanced miR-21 expression in primary pulmonary fibroblasts. Increasing miR-21 levels promoted, whereas knocking down miR-21 attenuated, the pro-fibrogenic activity of TGF-beta1 in fibroblasts. A potential mechanism for the role of miR-21 in fibrosis is through regulating the expression of an inhibitory Smad, Smad7. These experiments demonstrate an important role for miR-21 in fibrotic lung diseases and also suggest a novel approach using miRNA therapeutics in treating clinically refractory fibrotic diseases, such as IPF.

Involvement of lymphatics in lymphangioleiomyomatosis

Lymphangioleiomyomatosis (LAM), a rare multisystem disease, occurs primarily in women, with cystic destruction of the lungs, abdominal tumors, and involvement of the axial lymphatics in the thorax and abdomen. To understand the pathogenesis of LAM, we initiated a longitudinal study of patients with LAM; over 500 patients have been enrolled. LAM results from the proliferation of a neoplastic cell (LAM cell), which has mutations in the tuberous sclerosis complex (TSC) genes, TSC1 or TSC2. Consistent with their metastatic behavior, LAM cells were isolated from blood, urine, and chylous effusions. Surface proteins on LAM cells include those found on metastatic cells and those involved in cell migration. In the lung, LAM cells are found clustered in nodules, which appear in the walls of the cysts, and in the interstitium. LAM lung nodules are traversed by slit-like vascular structures, with lining cells showing reactivity with antibodies against components of lymphatic endothelial cells. The axial lymphatics appear to be infiltrated by LAM cells, which may result in obstruction and formation of chyle-filled lymphangioleiomyomas. LAM cell clusters have been isolated from chylous pleural effusions, and it is hypothesized that these clusters may be responsible for metastatic spread of LAM cells via lymphatic vessels. Consistent with a lymphangiogenic process, levels of VEGF-D, a lymphangiogenic factor, were higher in sera of patients with LAM and lymphatic involvement (i.e., lymphangioleiomyoma, adenopathy) than in healthy volunteers or LAM patients with cystic disease limited to the lung. These findings are consistent with an important function for lymphangiogenesis in LAM.

Cytokine-dependent balance of mitogenic effects in primary human lung fibroblasts related to cyclic AMP signaling and phosphodiesterase 4 inhibition

Interleukin-1beta (IL-1beta) and basic fibroblast growth factor (bFGF) are important regulators of proliferation, and their expression is increased in lungs of patients with asthma, idiopathic pulmonary fibrosis (IPF), or chronic obstructive pulmonary disease (COPD). We investigated the effect of IL-1beta and bFGF on proliferation of human lung fibroblasts and the role of COX-2, PGE(2), and cAMP in this process. Furthermore, the effect of phosphodiesterase (PDE) 3 and 4 inhibition was analyzed. In primary human lung fibroblasts low concentrations of IL-1beta (<10 pg/ml) potentiated the bFGF-induced DNA synthesis, whereas higher concentrations revealed antiproliferative effects. Higher concentrations of IL-1beta-induced COX-2 mRNA and protein associated with an increase in PGE(2) and cAMP, and all of these parameters were potentiated by bFGF. The PDE4 inhibitor piclamilast concentration-dependently reduced proliferation by a partial G1 arrest. The PDE3 inhibitor motapizone was inactive by itself but enhanced the effect of the PDE4 inhibitor. This study demonstrates that bFGF and IL-1beta act in concert to fine-tune lung fibroblast proliferation resulting in amplification or reduction. The antiproliferative effect of IL-1beta is likely attributed to the induction of COX-2, which is further potentiated by bFGF, and the subsequent generation of PGE(2) and cAMP. Inhibition of PDE4 inhibition (rather than PDE3) may diminish proliferation of human lung fibroblasts and therefore could be useful in the therapy of pathological remodeling in lung diseases.

Bleomycin induces upregulation of lysyl oxidase in cultured human fetal lung fibroblasts

AIM

To investigate the mechanism of bleomycin (BLM)-induced pulmonary fibrosis.

METHODS

Cultured human fetal lung fibroblast (HLF) cells were exposed to bleomycin (BLM) at 0-30 microg/mL for 24 h. Western blot analysis was used to detect lysyl oxidase (LO) protein expression. Real-time RT-PCR was used to detect LO mRNA level. LO catalytic activity was measured using diaminopentane as a substrate and Amplex red as a hydrogen peroxide probe. Copper (Cu) concentration was detected by flame atomic absorption spectrophotometry.

RESULTS

Exposure of HLF cells to BLM at 10 microg/mL and 30 microg/mL increased LO catalytic activity to 130% and 158% of the control in the conditioned media. The expression of LO mRNA was increased to 5.5-fold of the control in HLF cells exposure to BLM at 3 microg/mL. BLM at 3 microg/mL also increased the expression of 46 kDa preproLO, 50 kDa proLO and 32 kDa mature LO to 219%, 130%, and 135% of the control, respectively. The Cu concentrations in conditioned media of cultured HLF cells exposed to BLM (10 and 30 microg/mL) were increased significantly to 1.48 and 2.46-fold of the control, respectively.

CONCLUSION

Bleomycin induces upregulation of LO in cultured human fetal lung fibroblasts, which may be the mechanism of bleomycin-induced pulmonary fibrosis.

Dose-dependent osteoinductive effects of bFGF in rabbits

Growth factors lead to the induction of tissue regeneration in bone healing when coated on biomaterials. Basic fibroblast growth factor (bFGF) combines osteoinduction and neoangiogenesis. This study evaluated bFGF-coated hydroxylapatite implants in two experimental groups with 10 or 100 microg (n = 5 per group) compared with uncoated control implants in the rabbit patellar groove model. We observed an unexpected ineffectiveness compared to the control groups with no significant difference of bone growth after 35 days. However, all samples from the 100 microg experiment (control and coated implant) showed significantly stronger 19-25 day label than both 10 microg groups (control and coated implant). Earlier bone labels are stronger in the 10 microg group with equal observation of similarity between experiment and control site and may indicate a possible inhibitory effect of the higher dosing or osteoclast induction. This result indicates a possible systemic effect of the transient growth factor coating.

Gene expression profiling of pulmonary fibrosis identifies Twist1 as an antiapoptotic molecular "rectifier" of growth factor signaling

Idiopathic pulmonary fibrosis (IPF) is a progressive and typically fatal lung disease. To gain insight into IPF pathogenesis, we performed gene expression profiling of IPF lungs. Twist1, a basic helix-loop-helix protein, was found among the most consistently and highly up-regulated genes and was expressed in nuclei of type II epithelial cells, macrophages, and fibroblasts in IPF lungs. We studied the function of Twist1 in fibroblasts further, because they are the major effector cells in this disease and persist despite an ambient proapoptotic environment. Twist1 was induced by the profibrotic growth factors (GFs) basic fibroblast growth factor, platelet-derived growth factor, and epidermal growth factor in primary rat lung fibroblasts (RLFs). Suppression of Twist1 expression resulted in decreased RLF accumulation due to increased apoptosis, whereas Twist1 overexpression protected RLFs against several apoptotic stimuli. Addition of platelet-derived growth factor in combination with other GFs led to an increase in proliferation. When Twist1 was depleted, GFs continued to act as mitogens but caused a marked increase in cell death. The increase in apoptosis under basal or growth factor-stimulated conditions was partly mediated by up-regulation of the proapoptotic Bcl-2 family members, Bim and PUMA. These findings indicate that Twist1 promotes survival and accumulation of fibroblasts by shaping their responsiveness to growth factor stimulation. We propose that Twist1 represents one of the factors that promotes pathogenic accumulation of fibroblasts in fibrotic lung disease.

Vascular endothelial growth factors C and D induces proliferation of lymphangioleiomyomatosis cells through autocrine crosstalk with endothelium

Lymphangioleiomyomatosis (LAM) is a potentially fatal lung disease characterized by nodules of proliferative smooth muscle-like cells. The exact nature of these LAM cells and their proliferative stimuli are poorly characterized. Herein we report the novel findings that the lymphangiogenic vascular endothelial growth factors (VEGF) C and D induce LAM cell proliferation through activation of their cognate receptor VEGF-R3 and activation of the signaling intermediates Akt/mTOR/S6. Furthermore, we identify expression of the proteoglycan NG2, a marker of immature smooth muscle cells, as a characteristic of LAM cells both in vitro and in human lung tissue. VEGF-C-induced LAM cell proliferation was in part a result of autocrine stimulation that resulted from cross talk with lymphatic endothelial cells. Ultimately, these findings identify the lymphangiogenic VEGF proteins as pathogenic growth factors in LAM disease and at the same time provide a novel pharmacotherapeutic target for a lung disease that to date has no known effective treatment.

Fibrillar collagen clamps lung mesenchymal cells in a nonproliferative and noncontractile phenotype

Pulmonary fibrosis is characterized by phenotypic changes to mesenchymal cells and an increase in the deposition of fibrillar collagen (fCollagen). This study investigated the effect of type I fCollagen on the phenotypic plasticity of human parenchymal fibroblasts (PFbs) in vitro. Cell numbers were 45% lower when cultured on fCollagen as compared with culture on its degradation product, monomeric collagen (mCollagen). DNA profiles indicated that fCollagen is antiproliferative, rather than proapoptotic. fCollagen suppressed basic fibroblast growth factor-stimulated increases in the levels of cyclin E and CDK2 mRNA. fCollagen also suppressed transforming growth factor-beta (100 pM)-stimulated increases in the mRNA and protein levels of alpha-smooth muscle actin (alpha-SMA), a marker of the myofibroblast phenotype. However, in cells exposed to fCollagen, the levels of matrix metalloproteinase (MMP)-1 and -14 mRNA, as well as active MMP-2 protein, were increased by between two- and fivefold. The MMP inhibitors, ilomastat (10 microM) and doxycycline (30 microM), attenuated the dissolution of collagen fibrils by fibroblasts maintained on fCollagen, with a corresponding decrease in cell number. Ilomastat also reduced alpha-SMA expression and the capacity of PFb to contract three-dimensional fCollagen gels. Thus, exposure of fibroblasts to the fibrillar form of type I collagen in vitro reduces cell proliferation, increases MMP production and activation, and attenuates differentiation of PFb into myofibroblasts. fCollagen appears to apply a phenotypic clamp on lung fibroblasts that may be partially released by autocrine MMP activity.

Endothelial-derived FGF2 contributes to the progression of pulmonary hypertension in humans and rodents

Pulmonary hypertension (PH) is a progressive, lethal lung disease characterized by pulmonary artery SMC (PA-SMC) hyperplasia leading to right-sided heart failure. Molecular events originating in pulmonary ECs (P-ECs) may contribute to the PA-SMC hyperplasia in PH. Thus, we exposed cultured human PA-SMC to medium conditioned by P-EC from patients with idiopathic PH (IPH) or controls and found that IPH P-EC-conditioned medium increased PA-SMC proliferation more than control P-EC medium. Levels of FGF2 were increased in the medium of IPH P-ECs over controls, while there was no detectable difference in TGF-beta1, PDGF-BB, or EGF levels. No difference in FGF2-induced proliferation or FGF receptor type 1 (FGFR1) mRNA levels was detected between IPH and control PA-SMCs. Knockdown of FGF2 in P-EC using siRNA reduced the PA-SMC growth-stimulating effects of IPH P-EC medium by 60% and control P-EC medium by 10%. In situ hybridization showed FGF2 overproduction predominantly in the remodeled vascular endothelium of lungs from patients with IPH. Repeated intravenous FGF2-siRNA administration abolished lung FGF2 production, both preventing and nearly reversing a rat model of PH. Similarly, pharmacological FGFR1 inhibition with SU5402 reversed established PH in the same model. Thus, endothelial FGF2 is overproduced in IPH and contributes to SMC hyperplasia in IPH, identifying FGF2 as a promising target for new treatments against PH.

Antifibrotic action of pirfenidone and prednisolone: different effects on pulmonary cytokines and growth factors in bleomycin-induced murine pulmonary fibrosis

Pirfenidone, a broad-spectrum antifibrotic agent, is known to have efficacy in certain fibrotic disease models, and is under clinical trials in patients with idiopathic pulmonary fibrosis. We investigated the antifibrotic effect of pirfenidone, and its regulatory effect on various pulmonary cytokines, in bleomycin-induced lung fibrosis in mice at the protein level, using prednisolone as a reference agent. Pirfenidone attenuated the bleomycin-induced pulmonary fibrosis at a minimum effective dose of 30 mg/kg/day t.i.d. from the analysis of lung hydroxyproline content. Both pirfenidone (30, 100 mg/kg/day t.i.d) and prednisolone (3, 15 mg/kg/day q.d.) suppressed lung inflammatory edema; however, prednisolone failed to suppress pulmonary fibrosis, which was significantly suppressed only by pirfenidone. Both pirfenidone and prednisolone suppressed the increase in lung interleukin (IL)-1beta, IL-6, IL-12p40 and monocyte chemoattractant protein (MCP)-1 levels induced by bleomycin. On the other hand, pirfenidone prevented the bleomycin-induced decrease in lung interferon (IFN)-gamma levels, while prednisolone had no such effect. Furthermore, pirfenidone suppressed elevation of lung basic-fibroblast growth factor (bFGF) and transforming growth factor (TGF)-beta1 levels, but prednisolone had no such effect. The increases in lung stroma cell derived factor (SDF)-1alpha and IL-18 were also suppressed. These findings suggest that pirfenidone exerts its antifibrotic effect through regulation of lung IFN-gamma, bFGF and TGF-beta1 levels during the development of bleomycin-induced pulmonary fibrosis in mice. The effect on SDF-1alpha and IL-18 levels may also be related to the antifibrotic effects of pirfenidone.

The epidemiology of lymphangioleiomyomatosis in Japan: a nationwide cross-sectional study of presenting features and prognostic factors

BACKGROUND AND OBJECTIVE

To evaluate the characteristics and prognostic factors of Japanese patients with lymphangioleiomyomatosis (LAM).

METHODS

A nationwide survey to identify patients with LAM was conducted by questionnaire. Survival probability was estimated using the Kaplan-Meier method, and the prognostic factors were analysed by Cox regression.

RESULTS

Data were collected on 173 patients with pulmonary LAM. The major presenting features were pneumothorax (43%) and exertional dyspnoea (37%). The survival probabilities for patients presenting with exertional dyspnoea (Group A) were 85%, 60% and 47% after 5, 10 and 15 years, respectively, and for patients presenting with pneumothorax (Group B) were 95%, 89% and 89%, respectively. Although the age at symptom onset was higher among patients in Group A than in Group B, Cox regression revealed that the presenting feature was a prognostic factor independent of age at symptom onset (Group A/B hazard ratio = 5.732, P < 0.01). In the subgroup of patients whose initial FEV(1) was >1000 mL, or FEV(1)/FVC >40%, or %DL(CO) >40%, the rate of deterioration in these tests was greater in Group A than in Group B (P < 0.01 for FEV(1), P < 0.05 for FEV(1)/FVC and %DL(CO)).

CONCLUSIONS

There are two possible subgroups of LAM patients. One subgroup that presented with pneumothorax, had onset of symptoms at a younger age and a more favourable prognosis; the other presented with exertional dyspnoea, had onset of symptoms at an older age and a poorer prognosis.

Elastofibroma: a clinicopathologic and immunohistochemical study of seven cases and literature review

Elastofibroma is a rare fibrous lesion characterized by accumulated abnormal elastic fibers whose etiology remains largely unknown. In this study, we analyzed seven cases of elastofibroma to further explore the characteristics of its cellular composition. Immunohistochemistry was performed for mast cell tryptase, S-100 protein, vimentin, CD34, smooth muscle actin, desmin and collagen type IV. Histochemical staining methods for Gomori's trichrome and Verhoeff elastica-van Gieson were also evaluated. Histopathologically, a haphazard array of collagen, eosinophilic amorphous fibers, and globules in a fibrous tissue was seen. The elastic nature of the fibers was confirmed by elastic stain, and with Gomori's trichrome collagen fibers were also demonstrated. The interspersed spindle or stellate cells were almost consistently positive for vimentin and frequently positive for CD34. Mast cell tryptase-positive cells were present in five of the cases. Collagen type IV immunoreactivity was seen in two cases. No staining was observed with smooth muscle actin, desmin or S-100 protein. Our findings suggest that CD34-positive mesenchymal cells are an integral component of elastofibroma.

Marked stem cell factor expression in the airways of lung transplant recipients

BACKGROUND

Airways repair is critical to lung function following transplantation. We hypothesised that the stem cell factor (SCF) could play a role in this setting.

METHODS

We studied 9 lung transplant recipients (LTx recipients) during their first year postgraft, and evaluated SCF mRNA expression in bronchial biopsy specimens using on-line fluorescent PCR and SCF protein levels in bronchoalveolar lavage (BAL) and serum using ELISA. The expression of SCF receptor Kit was assessed using immunostaining of paraffin-embedded bronchial sections.

RESULTS

SCF mRNA was highly expressed during the early postgraft period [Month (M)1-M3] (300% increase vs controls: 356 vs 1.2 pg SCF/microg GAPDH cDNA, p < 0.001) and decreased thereafter (M4-M12: 187 pg/microg), although remaining at all times 10-100 times higher than in controls. While SCF protein levels in BAL were similar in LTx recipients and in controls, the SCF serum levels were at all times higher in LTx recipients than in controls (p < 0.05), with no relationship between these levels and the acute complications of the graft. Finally, Kit was strongly expressed by the mast cells as well as by the bronchial epithelium of LTx recipients.

CONCLUSION

SCF and Kit are expressed in bronchial biopsies from lung transplant recipients irrespective of the clinical status of the graft. A role for these factors in tissue repair following lung transplantation is hypothesised.

Morphological and quantitative assessment of mast cells in rheumatoid arthritis associated non-specific interstitial pneumonia and usual interstitial pneumonia

BACKGROUND

The role of mast cells in extra-articular manifestations of rheumatoid arthritis (RA) has not been studied so far.

OBJECTIVE

To characterise and quantify mast cells in RA associated interstitial pneumonia (IP) by an immunohistological study.

METHODS

Lung biopsy specimens from 15 patients with RA associated IP, 12 patients with idiopathic IP, and 5 control patients were stained with antibodies directed against tryptase (mast cell marker). Morphological characterisation of stained specimens was carried out and staining was quantified by computer assisted image analysis.

RESULTS

Tryptase staining showed the marked presence of mast cells in idiopathic IP and in RA associated IP. A significant difference in stained tissue area was found between RA associated IP (2.6%, IQR 2.0-3.2%, p = 0.015) and idiopathic IP (3.1%, IQR 1.8-3.7%, p = 0.003) compared with control tissue specimens (1.0%, IQR 0.7-1.5%). The extent of mast cell infiltration correlated well and inversely with pulmonary function variables.

CONCLUSIONS

Mast cell infiltrates are present in RA associated IP and idiopathic IP. The observed correlation of pulmonary function and mast cell numbers would be consistent with the proposed role of mast cell mediators in the promotion of fibrogenesis. The findings provide a rationale for studying functional aspects of mast cell involvement in the pathogenesis of RA associated lung disease.

Discoidin domain receptor 1 contributes to the survival of lung fibroblast in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF), characterized by fibroblast proliferation and accumulation of extracellular matrix, including collagen, is a chronic progressive disorder that results in lung remodeling and fibrosis. However, the cellular mechanisms that may make fibroblasts resistant to apoptosis have not been completely elucidated. Discoidin domain receptor 1 (DDR1), a receptor tyrosine kinase whose ligand is collagen, is expressed in vivo and contributes in vitro to leukocyte differentiation and nuclear factor (NF)-kappaB activation, which may play an important role in fibroblast survival. In this study, we examined in vivo and in vitro DDR1 expression and its role in cell survival using fibroblasts obtained from IPF and non-IPF patients. Immunohistochemically, fibroblasts present in fibroblastic foci expressed endogenous DDR1. The DDR1 expression level was significantly higher in fibroblasts from IPF patients, and the predominant isoform was DDR1b. In IPF patients, DDR1 activation in fibroblasts inhibited Fas ligand-induced apoptosis and resulted in NF-kappaB nuclear translocation. Suppression of DDR1 expression in fibroblasts by siRNA abolished these effects, and an NF-kappaB inhibitor abrogated the anti-apoptotic effect of DDR1 activation. We propose that DDR1 contributes to fibroblast survival in the tissue microenvironment of IPF and that DDR1 up-regulation may occur in other fibroproliferative lung diseases as well.

ORIGINAL RESEARCH—BASIC SCIENCE: Intracavernosal Basic Fibroblast Growth Factor Improves Vasoreactivity in the Hypercholesterolemic Rabbit

PURPOSE

We determined the effects of intracavernosal injection (ICI) of recombinant basic fibroblast growth factor (rbFGF) on corporal tissue in hypercholesterolemic rabbits.

METHODS

Twenty New Zealand White rabbits were fed a 1% cholesterol diet for 6 weeks and were randomly divided into four groups. Group 1 (N = 5) received an ICI of phosphate buffered saline solution (PBS) once and again 3 weeks later. Group 2 (N = 4) received an ICI of 2.5 microg rbFGF once and PBS 3 weeks later. Group 3 (N = 6) received an ICI of 2.5 microg rbFGF once and again 3 weeks later. Group 4 (N = 5) received an ICI of 2.5 microg rbFGF once. All animals were maintained on the high cholesterol diet until sacrifice, 3 weeks after last injection. Strips of corporal tissue were submaximally contracted with norepinephrine, and dose-response curves were generated to evaluate endothelial-dependent (acetylcholine, ACH) and endothelial-independent (sodium nitroprusside, SNP) vasoreactivity. Protein levels of bFGF and vascular endothelial growth factor (VEGF) were assessed by enzyme-linked immunosorbent assay. Neuronal nitric oxide synthase (nNOS) protein and mRNA were detected by Western blot and semi-quantitative polymerase chain reaction, respectively.

RESULTS

Vasoreactivity was improved by bFGF treatment as shown by higher ED50[-log(M)] of ACH and SNP in Groups 2, 3, and 4. The expression of bFGF protein, VEGF protein, nNOS protein, and mRNA were all increased after bFGF treatment.

CONCLUSIONS

ICI of bFGF improved vasoreactivity in hypercholesterolemic rabbit corporal tissue, offering a new direction to explore for the treatment of erectile dysfunction.

Tissue-specific renin-angiotensin system in pulmonary lymphangioleiomyomatosis

Lymphangioleiomyomatosis (LAM), a multisystem disease found in middle-aged women, is characterized by cystic lung destruction and abdominal tumors (e.g., angiomyolipomas, lymphangioleimyomas), resulting from proliferation of abnormal-appearing, smooth muscle-like cells (LAM cells). The LAM cells, in combination with other cells, form nodular structures within the lung interstitium and in the walls of the cysts. LAM cells contain mutations in the tuberous sclerosis complex TSC1 and/or TSC2 genes, which lead to dysregulation of the mammalian target of rapamycin, affecting cell growth and proliferation. Proliferation and migration of vascular smooth muscle cells and production of angiogenic factors are regulated, in part, by angiotensin II. To determine whether a LAM-specific renin-angiotensin system might play a role in the pathogenesis of LAM, we investigated the expression of genes and gene products of this system in LAM nodules. mRNA for angiotensinogen was present in RNA isolated by laser-captured microdissection from LAM nodules. Angiotensin I-converting enzyme and chymase-producing mast cells were present within the LAM nodules. We detected renin in LAM cells, as determined by the presence of mRNA and immunohistochemistry. Angiotensin II type 1 and type II receptors were identified in LAM cells by immunohistochemistry and immunoblotting of microdissected LAM nodules. Angiotensin II is localized in cells containing alpha-smooth muscle actin (LAM cells). A LAM-specific renin-angiotensin system appears to function within the LAM nodule as an autocrine system that could promote LAM cell proliferation and migration, and could represent a pharmacologic target.

c-Kit immunophenotyping and metalloproteinase expression profiles of mast cells in interstitial lung diseases

Diverse interstitial lung diseases (ILD) demonstrate mesenchymal infiltration by an abundance of activated mast cells whose role in parenchymal fibrogenesis remains unclear. Since mast cells differentiate in a dynamic, tissue-specific manner via signals transduced by c-Kit receptor, we examined the effect of ILD microenvironments on c-Kit expression and metalloproteinase phenotypes of mesenchymal mast cell populations. Immunohistochemical and flow cytometric analyses characterized surface expression of c-Kit on mast cells in tissues obtained from patients with idiopathic pulmonary fibrosis, systemic sclerosis, sarcoidosis, and lymphangioleiomyomatosis, thus identifying a unique immunophenotype not shared by normal lung mast cells. Isolation of c-Kit+/FcepsilonRI+/CD34- mast cells via immunocytometric sorting of heterogeneous cell populations from mechanically disaggregated lung tissues permitted analysis of gene expression patterns by two-step real-time polymerase chain reaction. Transcriptional profiling identified expression of c-Kit and the neutral serine proteases, tryptase and chymase, establishing the identity of sorted populations as mature mast cells. Mast cells harvested from ILD tissues demonstrated characteristic metalloproteinase phenotypes which included expression of matrix metalloproteinase (MMP)-1 and a disintegrin and metalloproteinase (ADAM)-9, -10, and -17. Immunohistochemical co-localization guided by gene profiling data confirmed expression of chymase, MMP-1, and ADAM-17 protein in subpopulations of mast cells in remodelling interstitium. Gene profiling of harvested mast cells also showed increased transcript copy numbers for TNFalpha and CC chemokine receptor 2, which play critical roles in lung injury. We conclude that ILD microenvironments induce unique c-Kit receptor and metalloproteinase mast cell phenotypes.

Distribution of elastic fiber in tissues of normal stomach, stomach ulcer and stomach carcinoma

AIM: To study the distribution of elastic fiber (EF) in tissues of normal stomach, gastric ulcer and gastric carcinoma.

METHODS: Tissue samples, including 40 cases of stomach carcinoma, 17 cases of normal stomach and 7 cases of stomach ulcer, were studied using hematoxylin and eosin (HE) staining and EF staining. The distributions of EF were analyzed under light microscope.

RESULTS: In tissues of stomach ulcer, EF, with a deep staining, was mainly located in the muscularis mucosa adjacent to the ulcer lesion. No EF was observed in carcinoma zone, but a great amount was found in the smooth muscle and connective tissue around the lesion. EF was increased significantly in stomach carcinoma specimens, compared with that in normal tissues (P = 0.0042). Hyperplasia of small vessel endothelia was observed in cancer tissues but not in ulcer tissues.

CONCLUSION: The distribution patterns of EF are different in normal stomach, gastric ulcer and gastric carcinoma. The increase of EF in gastric ulcer may be related to the stimulation of chronic inflammation; while in carcinoma, in addition to the chronic inflammatory stimulation, the EF increase in the surrounding tissues may also result from augmented EF production triggered by the cancer cells indirectly through releasing stimulatory factors or directly via regulating gene expression in EF-producing cells. The increase of EF in the stomach wall lesion is a chronic process.

Plasma basic fibroblast growth factor and bone marrow fibrosis in clonal myeloproliferative disorders

Basic fibroblast growth factor (bFGF) is an important growth factor involved in clonal hematopoietic expansion, neoangiogenesis, and bone marrow fibrosis, all of which are important pathobiologic features of clonal chronic myeloproliferative disorders (CMPD) and myelodysplastic syndromes (MDS). The aim of this study was to assess circulating bFGF concentrations in patients with CMPD and MDS with respect to the presence of bone marrow fibrosis in histopathologic examination. The study group comprised 18 patients with CMPD (six female, 12 male; median age 50 years), seven patients with MDS (one female, six male; median age 66 years) and 10 healthy adults as controls (four female, six male; median age 29 years). CMPD group included six chronic myelogenous leukemia (CML), seven essential thrombocythemia (ET), three polycythemia vera (PV), two agnogenic myeloid metaplasia (AMM). All seven MDS patients were the FAB subtype of refractory anemia (RA). Bone marrow biopsy sections stained with hematoxylin and eosin (H & E) and for reticulin were examined for the presence of fibrosis. The median plasma bFGF level was 18.2 pg/ml (interquartile range, IQR: 15.2-26.7) in patients with CMPD, 18.0 pg/ml (IQR: 15.8-26.4) in patients with MDS, 13.6 pg/ml (IQR: 9.9-20.0) in the control group. The bFGF levels were significantly higher in patients with CMPD in comparison with the healthy control group (P = 0.031). Circulating bFGF tended to be significantly lower in relation to the development of marrow fibrosis (P = 0.028). The complicated interactions of bFGF and fibrosis in the context of CMPD may be either 'cause' or 'effect'. The bFGF might represent an important link between angiogenesis, fibrosis, and clonal neoplastic hematopoiesis during the development of CMPD.

Idiopathic pulmonary fibrosis: current understanding of the pathogenesis and the status of treatment

Idiopathic pulmonary fibrosis (IPF) is a progressive and lethal pulmonary fibrotic lung disease. The diagnostic histological changes are called usual interstitial pneumonia and are characterized by histological temporal heterogeneity, whereby normal lung tissue is interspersed with interstitial fibrosis, honeycomb cysts and fibroblast foci. Pulmonary functions show restricted volumes and capacities, preserved flows and evidence of decreased gas exchange. High-resolution computed axial tomography demonstrates evidence of fibrosis and lung remodelling such as honeycomb cysts and traction bronchiectasis. There is no known effective treatment for IPF, but lung transplantation improves survival.

Systemic basic fibroblast growth factor induces favorable histological changes in the corpus cavernosum of hypercholesterolemic rabbits

PURPOSE

Hypercholesterolemia causes erectile dysfunction that is associated with abnormalities in vascular smooth muscle and endothelial cells. We determined the effects of basic fibroblast growth factor (bFGF) on corporeal tissue in hypercholesterolemic rabbits.

MATERIALS AND METHODS

A total of 16 New Zealand White rabbits were fed a 1% cholesterol diet for 6 weeks and were randomly divided into 3 groups. Group 1 (5 rabbits) received 2.5 microg recombinant bFGF intravenously once and again 3 weeks later. Group 2 (6 rabbits) received 2.5 microg bFGF intravenously once and placebo 3 weeks later. Group 3 (5 rabbits) received placebo intravenously each time. Rabbits were continuously fed a 1% cholesterol diet and sacrificed 3 weeks after the last treatment. Smooth muscle, endothelial cell and collagen content were assessed by immunohistochemistry and histochemical staining of corporeal tissue. Vascular endothelial growth factor (VEGF) protein and mRNA expression were assessed by enzyme-linked immunosorbent assay and reverse transcriptase-polymerase chain reaction.

RESULTS

Corporeal smooth muscle content was greater in groups 1 and 2 (35.24% +/- 4.25% and 24.79% +/- 3.39%, p <0.01) vs group 3 (19.68% +/- 2.94%, vs groups 1 and 2 p <0.001 and <0.05, respectively). Endothelial cell and collagen content were similar among the groups. VEGF protein was increased in group 1 vs group 2 (97.90 +/- 26.00 vs 57.03 +/- 14.99 pg/ml, p <0.01) and vs group 3 (39.93 +/- 15.08, p <0.01). There was no statistical difference between groups 2 and 3. VEGF mRNA expression was similar among the groups.

CONCLUSIONS

Systemic bFGF increases smooth muscle content and VEGF protein in hypercholesterolemic rabbit corporeal tissue.

Mast cells and human hepatocellular carcinoma

AIM: To investigate the density of mast cells (MCs) in human hepatocellular carcinoma (HCC), and to determine whether the MCs density has any correlations with histopathological grading, staging or some baseline patient characteristics.

METHODS: Tissue sections of 22 primary HCCs were histochemically stained with toluidine blue, in order to be able to quantify the MCs in and around the neoplasm using a computer-assisted image analysis system. HCC was staged and graded by two independent pathologists. To identify the sinusoidal capillarisation of each specimen 3 μm thick sections were histochemically stained with sirius red, and semi-quantitatively evaluated by two independent observers. The data were statistically analysed using Spearman's correlation and Student's t-test when appropriate.

RESULTS: MCs density did not correlate with the age or sex of the patients, the serum alanine aminotransferase (ALT) or aspartate aminotransferase (AST) levels, or the stage or grade of the HCC. No significant differences were found between the MCs density of the patients with and without hepatitis C virus infection, but they were significantly higher in the specimens showing marked sinusoidal capillarisation.

CONCLUSION: The lack of any significant correlation between MCs density and the stage or grade of the neoplastic lesions suggests that there is no causal relationship between MCs recruitment and HCC. However, as capillarisation proceeds concurrently with arterial blood supply during hepatocarcinogenesis, MCs may be considered of primary importance in the transition from sinusoidal to capillary-type endothelial cells and the HCC growth.

Gene expression profiling of inflammatory bladder disorders

Inflammation underlies all major bladder pathologies including malignancy and represents a defense reaction to injury caused by physical damage, chemical substances, micro-organisms or other agents. During acute inflammation, activation of specific molecular pathways leads to an increased expression of selected genes whose products attack the insult, but ultimately should protect the tissue from the noxious stimulus. However, once the stimulus ceases, gene-expression should return to basal levels to avoid tissue damage, fibrosis, loss of function, and chronic inflammation. If this down-regulation does not occur, tissue fibrosis occurs as a serious complication of chronic inflammation. Although sensory nerve and most cells products are known to be key parts of the inflammatory puzzle, other key molecules are constantly being described that have a role in bladder inflammation. Therefore, as the database describing the repertoire of inflammatory mediators implicated in bladder inflammation increases, the central mechanisms by which injury can induce inflammation, cell damage, and repair often becomes less rather than more clear. To make sense of the vast knowledge of the genes involved in the inflammatory response may require analysis of the patterns of change and the elucidation of gene networks far more than definition of additional members of inflammatory cascades. This review discuss the appropriate use of microarray technology, which promises to solve both of these problems as well as identifying key molecules and mechanisms involved in the transition between acute and chronic inflammation.