Expression of insulin-like growth factor binding proteins in bronchoalveolar lavage fluid of patients with pulmonary sarcoidosis

Effects and potential mechanisms of IGF1/IGF1R in the liver fibrosis: A review

Liver fibrosis is a wound-healing response due to persistent liver damage and it may progress to cirrhosis and even liver cancer if no intervention is given. In the current cognition, liver fibrosis is reversible. So, it is of great significance to explore the related gene targets or biomarker for anti-fibrosis of liver. Insulin like growth factor 1 (IGF1) and IGF1 receptor (IGF1R) are mainly expressed in the liver tissues and play critical roles in the liver function. The present review summarized the role of IGF1/IGF1R and its signaling system in liver fibrosis and illustrated the potential mechanisms including DNA damage repair, cell senescence, lipid metabolism and oxidative stress that may be involved in this process according to the studies on the fibrosis of liver or other organs. In particular, the roles of IGF1 and IGF1R in DNA damage repair were elaborated, including membrane-localized and nucleus-localized IGF1R. In addition, for each of the potential mechanism in anti-fibrosis of liver, the signaling pathways of the IGF1/IGF1R mediated and the cell species in liver acted by IGF1 and IGF1R under different conditions were included. The data in this review will support for the study about the effect of IGF1/IGF1R on liver fibrosis induced by various factors, meanwhile, provide a basis for the study of liver fibrosis to focus on the communications between the different kinds of liver cells.

IGFBP-6 Network in Chronic Inflammatory Airway Diseases and Lung Tumor Progression

The lung is an accomplished organ for gas exchanges and directly faces the external environment, consequently exposing its large epithelial surface. It is also the putative determinant organ for inducing potent immune responses, holding both innate and adaptive immune cells. The maintenance of lung homeostasis requires a crucial balance between inflammation and anti-inflammation factors, and perturbations of this stability are frequently associated with progressive and fatal respiratory diseases. Several data demonstrate the involvement of the insulin-like growth factor (IGF) system and their binding proteins (IGFBPs) in pulmonary growth, as they are specifically expressed in different lung compartments. As we will discuss extensively in the text, IGFs and IGFBPs are implicated in normal pulmonary development but also in the pathogenesis of various airway diseases and lung tumors. Among the known IGFBPs, IGFBP-6 shows an emerging role as a mediator of airway inflammation and tumor-suppressing activity in different lung tumors. In this review, we assess the current state of IGFBP-6's multiple roles in respiratory diseases, focusing on its function in the inflammation and fibrosis in respiratory tissues, together with its role in controlling different types of lung cancer.

Increased Levels of IGF-1 and Beta2-Microglobulin in Epithelial Lining Fluid of Preterm Newborns Developing Chronic Lung Disease: Effects of rhG-CSF

Insulin-like growth factor-1 (IGF-1) is involved in regulating the TH-l/TH-2 balance, favoring the development of the TH-2 compartment which enhances fibrosis, one of the main characteristics of Chronic Lung Disease (CLD) in premature newborns. Limited data is available concerning a possible association between early epithelial lining fluid (ELF) concentrations of IGF-1 (total and free forms), IGF-binding protein-3 (IGFBP-3), b2-microglobulin (B2M) and subsequent development of CLD in preterm neonates. If neutropenic, preterm neonates are frequently treated with recombinant human Granulocyte Colony Stimulating Factor (rhG-CSF). The objective of the study was to correlate ELF concentrations of IGF-1 and B2M during the first week of life both in non-neutropenic and in rhG-CSF-treated neutropenic preterm neonates, with subsequent development in CLD. Thirty preterm neonates with Respiratory Distress Syndrome (6 with neutropenia) were studied. Eleven out of 24 non-neutropenic preterm infants (46%) and all of the six neutropenic subjects (100%) developed CLD. With the exception of first day values, there was a clear similarity in the behaviors of assayed molecules between non-neutropenic and neutropenic patients developing CLD. Non-neutropenic patients without CLD showed significantly lower values of free IGF-1 and B2M both on days 1 and 3. Total IGF-I and cell counts were different only on the 3rd day. Conclusions: 1) the mechanisms leading to CLD might be mediated by high levels of IGF-family molecules soon after birth 2) B2M could be a marker of increased bronchoalveolar lavage fluid cellularity with potential inflammatory properties 3) G-CSF treatment induces an increased synthesis of IGF-1 molecules by cells recruited in the lung, with possible enhancement of the fibrogenic mechanisms.

Insulin-Like Growth Factor-1 Signaling in Lung Development and Inflammatory Lung Diseases

Insulin-like growth factor-1 (IGF-1) was firstly identified as a hormone that mediates the biological effects of growth hormone. Accumulating data have indicated the role of IGF-1 signaling pathway in lung development and diseases such as congenital disorders, cancers, inflammation, and fibrosis. IGF-1 signaling modulates the development and differentiation of many types of lung cells, including airway basal cells, club cells, alveolar epithelial cells, and fibroblasts. IGF-1 signaling deficiency results in alveolar hyperplasia in humans and disrupted lung architecture in animal models. The components of IGF-1 signaling pathways are potentiated as biomarkers as they are dysregulated locally or systemically in lung diseases, whereas data may be inconsistent or even paradoxical among different studies. The usage of IGF-1-based therapeutic agents urges for more researches in developmental disorders and inflammatory lung diseases, as the majority of current data are collected from limited number of animal experiments and are generally less exuberant than those in lung cancer. Elucidation of these questions by further bench-to-bedside researches may provide us with rational clinical diagnostic approaches and agents concerning IGF-1 signaling in lung diseases.

Anti-TNFα therapy in inflammatory lung diseases

Increased levels of tumor necrosis factor (TNF) α have been linked to a number of pulmonary inflammatory diseases including asthma, chronic obstructive pulmonary disease (COPD), acute lung injury (ALI)/acute respiratory distress syndrome (ARDS), sarcoidosis, and interstitial pulmonary fibrosis (IPF). TNFα plays multiple roles in disease pathology by inducing an accumulation of inflammatory cells, stimulating the generation of inflammatory mediators, and causing oxidative and nitrosative stress, airway hyperresponsiveness and tissue remodeling. TNFα-targeting biologics, therefore, present a potentially highly efficacious treatment option. This review summarizes current knowledge on the role of TNFα in pulmonary disease pathologies, with a focus on the therapeutic potential of TNFα-targeting agents in treating inflammatory lung diseases.

Neutrophil gelatinase-associated lipocalin (NGAL) and insulin-like growth factor (IGF)-1 association with a Mannheimia haemolytica infection in sheep

This study was aimed at mapping the tissue distribution of some inflammatory parameters associated with a Mannheimia haemolytica (M. haemolytica) infection in sheep. The M. haemolytica was isolated and characterized from the affected lungs of slaughtered animals. Cytokines such as tumor necrosis factor (TNF)-α, interleukin (IL)-10, insulin-like growth factor (IGF)-1, as well as the acute-phase protein, neutrophil gelatinase-associated lipocalin (NGAL), were identified in the lung tissues, the serum, and the lymph nodes of M. haemolytica infected sheep, by enzyme-linked immunosorbent assay (ELISA). NGAL and IGF-1 pointed to an innate immune response, and epithelial cell repairing, respectively. The adaptive immune response was identified through the type of cytokines present in the affected sheep, as TNF-α represents the pro-inflammatory cytokines, and IL-10 represents the anti-inflammatory cytokines. M. haemolytica isolates were confirmed by polymerase chain reaction (PCR) and DNA sequences. There was a significant difference in the concentrations of NGAL, IGF-1, TNF-α, and IL-10, as observed in the affected sheep when compared to the healthy sheep. This study, for the first time, closely describes the distribution of some key and new inflammatory parameters in the tissue homogenate of affected lungs.

Growth factors and cytokines in acute lung injury

Cytokines and growth factors play an integral role in the maintenance of immune homeostasis, the generation of protective immunity, and lung reparative processes. However, the dysregulated expression of cytokines and growth factors in response to infectious or noxious insults can initiate and perpetuate deleterious lung inflammation and fibroproliferation. In this article, we will comprehensively review the contribution of individual cytokines and growth factors and cytokine networks to key pathophysiological events in human and experimental acute lung injury (ALI), including inflammatory cell recruitment and activation, alveolar epithelial injury and repair, angiogenesis, and matrix deposition and remodeling. The application of cytokines/growth factors as prognostic indicators and therapeutic targets in human ALI is explored.

Insulin-like growth factor binding proteins-3 and -5: central mediators of fibrosis and promising new therapeutic targets

Fibrosis involves an orchestrated cascade of events including activation of fibroblasts, increased production and deposition of extracellular matrix components, and differentiation of fibroblasts into myofibroblasts. Epithelial-mesenchymal cross-talk plays an important role in this process, and current hypotheses of organ fibrosis liken it to an aberrant wound healing response in which epithelial-mesenchymal transition (EMT) and cellular senescence may also contribute to disease pathogenesis. The fibrotic response is associated with altered expression of growth factors and cytokines, including increased levels of transforming growth factor-β1 (TGF-β1) and the more recent observation that increased levels of several insulin-like growth factor binding proteins (IGFBPs) are associated with a number of fibrotic conditions. IGFBPs have been implicated in virtually every cell type and process associated with the fibrotic response, making the IGFBPs attractive targets for the development of novel anti-fibrotic therapies. In this review, the current state of knowledge regarding the classical IGFBP family in organ fibrosis will be summarized and the clinical implications considered.

IGF1 and IGFBP3 in acute respiratory distress syndrome

OBJECTIVE

IGF1 and its most abundant binding protein, IGF-binding protein 3 (IGFBP3), have been implicated in fibrotic lung diseases and persistent acute respiratory distress syndrome (ARDS) due to profibrogenic and antiapoptotic activity. Whether circulating levels of IGF1 and IGFBP3 are altered in ARDS and whether they predict progression of and survival from ARDS remains unknown. This study aims to characterize the circulating levels of IGF1 and IGFBP3 in patients at risk for ARDS in relation to i) development of ARDS and ii) mortality among ARDS cases.

DESIGN

In this case-cohort study, consecutive patients with risk factors for ARDS admitted to the intensive care unit were enrolled and followed prospectively for the development of ARDS. Cases were followed for all-cause mortality through day 60. Of the 2397 patients enrolled in the parent study, plasma samples were available in 531 (22%) patients (356 controls and 175 cases) from early in presentation. Total plasma IGF1 and IGFBP3 levels were measured.

RESULTS

After adjusting for relevant clinical covariates including severity of illness, IGF1 and IGFBP3 levels were significantly lower in ARDS cases than in controls (odds ratio (OR), 0.58; P=0.006; OR, 0.57; P=0.0015 respectively). Among the ARDS cases, IGF1 and IGFBP3 levels were significantly lower in the 78 (45%) non-survivors (hazard ratio (HR), 0.70; P=0.024; HR, 0.69; P=0.021 respectively).

CONCLUSIONS

Lower circulating levels of IGF1 and IGFBP3 were independently associated with ARDS case status. Furthermore, lower levels were associated with mortality among the ARDS cases. These data support the role of the IGF pathway in ARDS.

Insulin-like growth factor-binding protein-3 (IGFBP-3) blocks the effects of asthma by negatively regulating NF-κB signaling through IGFBP-3R-mediated activation of caspases

Insulin-like growth factor-binding protein-3 (IGFBP-3) is a multifunctional protein known for modulating mitogenic and metabolic actions of IGFs as well as exerting a variety of biological actions not involving IGFs. Here, we show that IGFBP-3 blocks specific physiological consequences of asthma in an IGF-independent manner in vitro and in vivo. IGFBP-3 treatment effectively reduced all physiological manifestations of asthma examined in vivo (airway hyper-responsiveness, cellular and pathological changes in bronchoalveolar lavage fluid and lung tissue, and expression of numerous proinflammatory molecules). These unique IGFBP-3 effects were further confirmed in IGFBP-3-transgenic mice, thus strengthening the notion of IGFBP-3 actions within the respiratory system. Using human epithelial cells, we demonstrated the following: 1) IGFBP-3 blocks TNF-α-induced expression of proinflammatory molecules; 2) IGFBP-3 attenuates the TNF-α-induced migratory response of eosinophils; and 3) IGFBP-3 negatively regulates TNF-α-induced expression of the key NF-κB regulatory molecules IκBα and p65-NF-κB at the post-translational level. We identified that IGFBP-3 degrades IκBα and p65-NF-κB proteins through IGFBP-3 receptor (IGFBP-3R)-mediated activation of caspases thereby inhibiting TNF-α-induced activation of NF-κB signaling cascades. This unique IGFBP-3/IGFBP-3R action was further confirmed by demonstrating complete inhibition of IGFBP-3 action in the presence of caspase inhibitors as well as IGFBP-3R siRNAs. Non-IGF-binding IGFBP-3 mutants further proved the IGF-independent action of IGFBP-3. Our findings indicate that IGFBP-3 inhibits airway inflammation and hyper-responsiveness via an IGF-independent mechanism that involves activation of IGFBP-3R signaling and cross-talk with NF-κB signaling. The IGFBP-3/IGFBP-3R system therefore plays a pivotal role in the pathogenesis of asthma and can serve as a newly identified potential therapeutic target for this debilitating disease.

Role of growth factors in acute lung injury induced by paraquat in a rat model

Paraquat (PQ) can cause acute lung injury in humans and experimental animals. However, the role of growth factors in the progression of injury has not been clearly established. We developed an animal model of PQ-induced lung injury using Wistar rats. One milliliter of PQ solution (30, 60, and 120 mg/kg) was applied through the lavage, while the same amount of vehicle was applied to control rats. Based on histopathology, the lungs of some animals exposed to PQ showed acute fulmination, resulting in death, while others showed a more protracted injury, resulting in typical pulmonary fibrosis at 21 days. Using this PQ-poisoned rat model, we examined the intrapulmonary gene expression and circulatory level of cytokines and growth factors at 8 hours, 24 hours, 3 days, 7 days, 14 days, and 21 days after PQ administration. Semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) analysis demonstrated that the gene expression levels of interleukin-1 beta and interleukin-6 were significantly increased at 21 days after PQ challenge compared with the controls. The mRNA expression of tumor necrosis factor-alpha was also significantly increased except on days 14 and 21 after PQ treatment. Moreover, PQ-treated rats showed enhanced gene expression of growth factors such as platelet-derived growth factor-A and insulin-like growth factor-1 at 21 days and transforming growth factor-beta 1 at 14 days. ELISA results showed the circulatory level of cytokines and growth factors coincided with intrapulmonary gene expression. The synergistic effects of these molecules are presumed to cause pulmonary damage due to PQ challenge and may become targets of treatment.

Hypoglycemia due to ectopic secretion of insulin-like growth factor-I in a patient with an isolated sarcoidosis of the spleen

Hypoglycemia is reported to be one of the manifestations of a patient with hypothalamic sarcoid infiltrates due to impaired counter-regulation of glucose. But, without hypothalamic lesion, patients with sarcoidosis would not be expected to have hypoglycemia. We recently identified a patient with an isolated sarcoidosis of the spleen who had experienced frequent fasting hypoglycemia which completely disappeared after splenectomy. During hypoglycemia, serum insulin was undetectable. Endocrinological examination revealed no abnormality. The objective was to investigate whether the patient's hypoglycemia was due to ectopic secretion of an insulin-mimetic factor by the splenic sarcoidosis. Serum insulin-like growth factor-I (IGF-I) and IGF-II were measured by RIA. Serum visfatin and free IGF-I were by ELISA. A high molecular weight form of IGF-II, termed "big" IGF-II, was identified by Western blotting. Tissue IGF-I was quantified by real time RT-PCR after RNA extraction. Before operation, total and free serum IGF-I, serum IGF-II and serum visfatin were within reference range. Big IGF-II was not detected in patient's serum extract. After operation, hypoglycemia did not recur and serum insulin returned to normal, while serum IGF-I decreased by half the preoperative level. RT-PCR revealed that mRNA level of IGF-I in the sarcoidosis tissue was about 1.8-fold greater than that in the normal spleen tissue. These data suggest that ectopic secretion of IGF-I by the splenic sarcoidosis and its direct access to the liver via the portal vein might cause fasting hypoglycemia mainly by suppressing hepatic gluconeogenesis.

Role of insulin-like growth factor binding protein-3 in allergic airway remodeling

RATIONALE

The hallmarks of allergic asthma are airway inflammation, obstruction, and remodeling. Airway remodeling may lead to irreversible airflow obstruction with increased morbidity and mortality. Despite advances in the treatment of asthma, the mechanisms underlying airway remodeling are still poorly understood. We reported that insulin-like growth factor (IGF) binding proteins (IGFBPs) contribute to extracellular matrix deposition in idiopathic pulmonary fibrosis; however, their contribution to airway remodeling in asthma has not been established.

OBJECTIVES

We hypothesized that IGFBP-3 is overexpressed in asthma and contributes to airway remodeling.

METHODS

We evaluated levels of IGFBP-3 in tissues and bronchoalveolar lavage fluid from patients with asthma at baseline and 48 hours after allergen challenge, in reparative epithelium in an in vitro wounding assay, and in conditioned media from cytokine- and growth factor-stimulated primary epithelial cells.

MEASUREMENTS AND MAIN RESULTS

IGFBP-3 levels and distribution were evaluated by Western blot, ELISA, and immunofluorescence. IGFBP-3 is increased in vivo in the airway epithelium of patients with asthma compared with normal control subjects. The concentration of IGFBP-3 is increased in the bronchoalveolar lavage fluid of patients with asthma after allergen challenge, its levels are increased in reparative epithelium in an in vitro wounding assay and in the conditioned medium of primary airway epithelial cell cultures stimulated with IGF-I.

CONCLUSIONS

Our results suggest that one mechanism of allergic airway remodeling is through the secretion of the profibrotic IGFBP-3 from IGF-I-stimulated airway epithelial cells during allergic inflammation.

Insulin-like growth factor-I receptor blockade improves outcome in mouse model of lung injury

RATIONALE

The insulin-like growth factor-I (IGF-I) pathway is an important determinant of survival and proliferation in many cells. However, little is known about the role of the IGF-I pathway in lung injury. We previously showed elevated levels of IGF-I in bronchoalveolar lavage fluid from patients with acute respiratory distress syndrome. Furthermore, immunodepletion of IGF from acute respiratory distress syndrome bronchoalveolar lavage increased fibroblast apoptosis.

OBJECTIVES

We examined the effect of blockade of type 1 IGF tyrosine kinase receptor (IGF-IR) in a murine model of bleomycin-induced lung injury and fibrosis.

METHODS

Mice were treated with a monoclonal antibody against the IGF-I receptor (A12) or vehicle after intratracheal bleomycin instillation.

MEASUREMENTS AND MAIN RESULTS

Mice treated with A12 antibody had significantly improved survival after bleomycin injury compared with control mice. Both groups of mice had a similar degree of fibrosis on days 7 and 14, but by Day 28 the A12-treated group had significantly less fibrosis. Delayed treatment with A12 also resulted in decreased fibrosis. A12-treated mice had significantly decreased apoptotic cells on Day 28 compared with control mice. We confirmed that A12 treatment induced mouse lung fibroblast apoptosis in vitro. In addition, IGF-I increased lung fibroblast migration. The primary pathway activated by IGF-I in lung fibroblasts was the insulin receptor substrate-2/phosphatidylinositol 3-kinase/Akt axis.

CONCLUSIONS

IGF-I regulated survival and migration of fibrogenic cells in the lung. Blockade of the IGF pathway increased fibroblast apoptosis and subsequent resolution of pulmonary fibrosis. Thus, IGF-IR may be a potential target for treatment of lung injury and fibrosis.

The insulin-like growth factor (IGF) system and its relation to infliximab treatment in adult patients with Crohn's disease

OBJECTIVE

Metabolic bone disease (MBD) and muscle wasting (MW) are serious complications in adult patients suffering from inflammatory bowel disease. These complications may be caused by alterations in the insulin-like growth factor (IGF) system. The aim of the present study was to assess changes in the IGF system in patients with active Crohn's disease (CD) before and during infliximab treatment.

MATERIAL AND METHODS

We studied 13 patients with therapy refractory CD, treated with infliximab (5 mg/kg body-weight) at baseline and after 2 weeks. The IGF system and markers of inflammation were examined at baseline, on days 2-5 and after 1, 4, and 8 weeks. Ten healthy age- and gender-matched persons served as controls.

RESULTS

Total IGF-I and IGF binding protein (IGFBP)-3 levels were reduced by 36% (p<0.05) and 27% (p<0.001), respectively, compared with those of controls, and normalized during the study period. Free IGF-I levels were reduced by 46% (p<0.05) compared with those of controls and remained suppressed. IGFBP-2 levels were increased at baseline by a factor 2.3 compared to controls (p<0.01) with partial normalization at the end of the study period. The Crohn's disease Activity Index, the Harvey Bradshaw Index, C-reactive protein, orosomucoid and albumin reached normal levels during infliximab treatment.

CONCLUSIONS

Treatment with infliximab normalized circulating levels of total IGF-I and IGFBP-3, and partially normalized IGFBP-2, whereas free IGF-I remained suppressed. We suggest that the changes in the IGF system may be part of the catabolic state in active CD and may have an association with MBD and MW.

The insulin-like growth factor (IGF)-system in active ulcerative colitis and Crohn's disease: relations to disease activity and corticosteroid treatment

BACKGROUND

Metabolic bone disease (MBD) and muscle wasting (MW) are serious complications in adults suffering from inflammatory bowel disease (IBD). The inflammatory process and corticosteroid treatment may lead to changes in the IGF-system associated with MBD and MW.

AIM

To assess changes in the IGF-system and clinical and biochemical markers in ulcerative colitis (UC) and Crohn's disease (CD).

METHODS

We studied 37 IBD patients with severe clinical exacerbation (20 with UC, 17 with CD) before and during high dose corticosteroid treatment and tapering (8-12 weeks).

RESULTS

Total IGF-I was reduced in CD (36% p<0.01) and UC (41% p<0.001) before treatment and normalized completely. Free IGF-I baseline levels were unchanged compared to controls. In UC, free IGF-I levels increased significantly at week 1 and week 4 (p<0.01, respectively). In CD, no changes in free IGF-I levels were observed. IGFBP-2 baseline levels were increased by a factor 2.3 in UC and CD compared to controls (p<0.01 respectively) and normalized during treatment. IGFBP-3 was reduced by 38% (p<0.01) in CD and 32% (p<0.01) in UC with only partial normalization. Harvey-Bradshaw index, C - reactive protein and albumin normalized during treatment.

CONCLUSIONS

Significant changes in total and free IGF-I and IGFBP-2 and IGFBP-3 were demonstrated in CD and UC patients in exacerbation with only partial normalization during high dose corticosteroid treatment and tapering without differences between UC and CD. These changes may be part of MBD and MW in active IBD.

Mining the acute respiratory distress syndrome proteome: identification of the insulin-like growth factor (IGF)/IGF-binding protein-3 pathway in acute lung injury

To obtain a more complete protein profile of the airspace milieu in acute respiratory distress syndrome (ARDS) and to identify new mediators, we analyzed bronchoalveolar lavage fluid (BALF) by shotgun proteomics. Using BALF from three patients, we identified a total of 870 different proteins, a nearly 10-fold increase from previous reports. Among the proteins identified were known markers of lung injury, such as surfactant, proteases, and serum proteins. We also identified several biologically interesting proteins not previously identified in patients with ARDS, including insulin-like growth factor-binding protein-3 (IGFBP-3). Because of the known role of IGFBP-3 in regulating cell survival, we measured IGFBP-3 levels by enzyme-linked immunosorbent assay in ARDS BALF. Normal controls had low levels of IGFBP-3, whereas patients with early ARDS had a significant increase in IGFBP-3. The IGF pathway, acting through the type 1 IGF-receptor, repressed apoptosis of lung fibroblasts but not lung epithelial cells. Furthermore, depletion of IGF in ARDS BALF led to enhanced fibroblast apoptosis. Our data suggest that the IGFBP-3/IGF pathway is involved in the pathogenesis of lung injury, illustrating the power of shotgun proteomics to catalog proteins present in complex biological fluids, such as BALF, from which hypotheses can be developed and tested.

Analysis of insulin like growth factor 1 and insulin like growth factor binding protein 3 levels in bronchoalveolar lavage fluid and serum of patients with lung cancer

OBJECTIVE

Insulin like growth factor 1 (IGF-1) is recognized as a potent mitogen for many cancer cell lines and there is good evidence that lung cancer cells produce both IGF-1 and insulin like growth factor binding protein 3 (IGFBP-3). The aim of this study was to investigate the clinical significance of IGF-1 and IGFBP-3 levels in serum and in bronchoalveolar lavage (BAL) fluid by comparing lung cancer patients with healthy controls.

METHODS

BAL fluid and serum samples were obtained from 24 lung cancer patients and 12 healthy controls, and were analyzed for IGF-1 and IGFBP-3 levels by a two site immunoradiometric assay. The recovered BAL fluid was standardized by albumin to remove the variable of dilution and the data was expressed in epithelial lining fluid (ELF).

RESULTS

Serum IGF-1 and IGFBP-3 levels were lower in lung cancer patients, but the difference between the groups did not reach a statistical significance. IGF-1/IGFBP-3 ratio in ELF was significantly lower in lung cancer patients (P=0.035). Mean IGF-1 level in ELF was determined to be significantly lower in patients with distant metastasis (P=0.04). Serum IGF-1/IGFBP-3 ratio was found to be significantly lower in patients with distant (P=0.04) and nodal metastasis (P=0.03). Tumor stage was negatively correlated with IGF-1 level in ELF (P=0.05, r=-0.4) and serum IGF-1/IGFBP-3 ratio (P=0.04, r=-0.4).

CONCLUSION

IGF-1 and IGFBP-3 levels both in serum and ELF might serve a clinical significance in patients with lung cancer. However, further studies comprising more cases are needed to investigate the clinical significance of IGF-1 and IGFBP-3 in lung cancer.

Insulin-like growth factor binding proteins 3 and 5 are overexpressed in idiopathic pulmonary fibrosis and contribute to extracellular matrix deposition

Idiopathic pulmonary fibrosis (IPF) is a fibrotic disease of unknown etiology that results in significant morbidity and mortality. The pathogenesis of IPF is not completely understood. Because recent studies have implicated insulin-like growth factor-I (IGF-I) in the pathogenesis of fibrosis, we examined the expression and function of insulin-like growth factor binding proteins (IGFBP)-3 and -5 in IPF. IGFBP-3 and -5 levels were increased in vivo in IPF lung tissues and in vitro in fibroblasts cultured from IPF lung. The IGFBPs secreted by IPF fibroblasts are functionally active and can bind IGF-I, and IGFBPs secreted by primary fibroblasts bind extracellular matrix components. Our results also suggest that IGFBPs may be involved in the initiation and/or perpetuation of fibrosis by virtue of their ability to induce the production of extracellular matrix components such as collagen type I and fibronectin in normal primary adult lung fibroblasts. Although transforming growth factor-beta increased IGFBP-3 production by primary fibroblasts in a time-dependent manner, IGFBP-5 levels were not increased by transforming growth factor-beta. Taken together, our results suggest that IGFBPs play an important role in the development of fibrosis in IPF.

Total RNA yield and microarray gene expression profiles from fine-needle aspiration biopsy and core-needle biopsy samples of breast carcinoma

BACKGROUND

Gene expression profiling should be applicable to needle biopsy samples if microarray technology is to become practically useful for clinical research or management of breast carcinoma. This study compared gene expression profiles derived from fine-needle aspiration biopsy (FNAB) and from core needle biopsy (CBX).

METHODS

Total RNA was extracted from single FNAB and CBX samples. Corresponding pairs of FNAB and CBX were analyzed for similarity of gene expression profiles using cDNA microarrays that contain 30721 human sequences. A subset of genes that distinguished CBX samples from FNAB samples was evaluated in a larger group of needle biopsy samples and in a published genomic database derived from 78 sporadic breast carcinomas with known clinical outcome.

RESULTS

Sixty-eight patients with newly diagnosed breast carcinoma were included in the current study. Sixty-five patients underwent FNAB (17 had both FNAB and CBX) and 3 underwent CBX only. Extracted RNA was of suitable quality for hybridization in 46 (71%) FNABs and 15 (75%) CBXs. Total RNA yield in those samples was similar for single-pass FNAB (mean = 3.6 microg and median = 2.2 microg; n = 46) and CBX (mean = 2.8 microg and median = 2.0 microg; n = 15), with 1 microg or more of total RNA in all cases. Transcriptional profiling was performed successfully in all cases when it was attempted, in a total of 50 samples (38 FNABs and 12 CBXs), including matched FNAB and CBX samples from 10 patients. There were differences in gene expression profiles in 10 matched FNAB and CBX sample pairs. Genes that were expressed differently in CBX samples, compared with FNAB samples, were recognized as being predominantly from the endothelium, fibroblasts, myofibroblasts or smooth muscle, and histiocytes. Corresponding microscopic cell counts from FNABs demonstrated means of 80% tumor cells, 15% lymphocytes, and 5% stromal cells, whereas CBXs contained 50% tumor cells, 20% lymphocytes, and 30% stromal cells. Considering that CBXs are approximately six-fold richer in nonlymphoid stromal cells than FNABs and that CBXs differentially express a set of recognized stromal genes, the authors used these biopsies to define a transcriptional profile of breast carcinoma stroma. A set of 120 genes differentially expressed in CBXs was assessed independently in a published breast carcinoma genomic database to classify breast carcinomas based on stromal gene expression. Subgroups of tumors with low or high stromal signal were identified, but there was no correlation with the development of systemic metastases within 5 years.

CONCLUSIONS

Both FNAB and CBX yield a similar quality and quantity of total RNA and are suitable for cDNA microarray analyses in approximately 70-75% of single-pass samples. Transcriptional profiles from FNAB and CBX of the same tumor generally are similar and are driven by the tumor cell population. The authors concluded that each technique has relative advantages. The FNABs provide transcriptional profiles that are a purer representation of the tumor cell population, whereas transcriptional profiles from CBXs include more representation from nonlymphoid stromal elements. Selection of the preferred needle biopsy sampling technique for genomic studies of breast carcinomas should depend on whether variable stromal gene expression is desirable in the samples.

Localization of insulin-like growth factor-I in lung tissues of patients with fibroproliferative acute respiratory distress syndrome

Insulin-like growth factor-I (IGF-I) is elevated in human fibrotic lung diseases and in animal models of pulmonary fibrosis, implicating IGF-I in the pathogenesis of fibrotic lung disease. We questioned whether IGF-I protein levels were enhanced in fibroproliferative acute respiratory distress syndrome (FP-ARDS). Serial lung tissue sections from a biopsy database were immunohistochemically stained for IGF-I, IGF-I receptor, CD68, alpha-smooth muscle actin, collagens I and III, and proliferating cell nuclear antigen. Our results show enhanced staining of IGF-I and IGF-I receptor, collagens I and III, smooth muscle actin, CD68, and proliferating cell nuclear antigen in FP-ARDS compared with control lung sections. In FP-ARDS specimens, prominent staining of IGF-I and IGF-I receptor was seen in alveolar and interstitial macrophages as well as in a variety of mesenchymal cells. There was a correlation between IGF-I staining and CD68-positive cells, suggesting macrophages as a potential source of the IGF-I protein present in lungs. IGF-I also correlated with enhanced collagen I, collagen III, and proliferating cell nuclear antigen immunoreactivity, suggesting that IGF-I may play a role in the extracellular matrix protein deposition and cellular proliferation seen in the lungs of individuals with FP-ARDS. Our results indicate that IGF-I is increased in FP-ARDS and may be an important mediator in the progression of acute lung injury to FP-ARDS.

Roles for insulin-like growth factor I and transforming growth factor-beta in fibrotic lung disease

Idiopathic pulmonary fibrosis (IPF) is a lung disease that is characterized by epithelial cell damage and areas of denuded basement membrane resulting in inflammation, fibroblast proliferation, excessive extracellular matrix (ECM) deposition, and remodeling of alveolar gas exchange units. The progressive loss of lung gas exchange units in patients with IPF leads to respiratory failure and eventually to death. While the etiology of this disease is unknown, for many years studies suggested that chronic inflammation was the underlying factor that caused fibroproliferation and structural alterations of the lung. Recent data show that fibroproliferation and fibrosis can occur independently of inflammation, suggesting that IPF is a disease caused by a mesenchymal, rather than an immune disorder. Mesenchymal growth factors, including transforming growth factor (TGF)-beta, insulin-like growth factor (IGF)-I, platelet-derived growth factor, connective tissue growth factor, fibroblast growth factors, and keratinocyte growth factors, as well as proinflammatory cytokines such as tumor necrosis factor-alpha and interleukin-1beta, have been shown to be exaggerated in several fibrotic lung disorders including IPF, ARDS, sarcoidosis, and bronchopulmonary dysplasia, as well as pulmonary manifestations of systemic diseases such as rheumatoid arthritis or progressive systemic sclerosis (scleroderma). We argue that inflammation is required to initiate growth factor production and repair of the damaged alveolar epithelial lining in fibrotic lung diseases and that exaggerated TGF-beta production may be responsible for the fibrotic response seen in diseases such as IPF. We recognize the potential role of several growth factors in the fibroproliferative process in the lung, and in this brief report we focus on the possible roles of the growth factors IGF-I and TGF-beta in cell migration, proliferation, and ECM synthesis in patients with IPF.

Metalloproteinase and growth factor interactions: do they play a role in pulmonary fibrosis?

Chronic lung disease due to interstitial fibrosis can be a consequence of acute lung injury and inflammation. The inflammatory response is mediated through the migration of inflammatory cells, actions of proinflammatory cytokines, and the secretion of matrix-degrading proteinases. After the initial inflammatory insult, successful healing of the lung may occur, or alternatively, dysregulated tissue repair can result in scarring and fibrosis. On the basis of recent insights into the mechanisms underlying acute lung injury and its long-term consequences, data suggest that proteinases, such as the matrix metalloproteinases (MMPs), may not only be involved in the breakdown and remodeling that occurs during the injury but may also cause the release of growth factors and cytokines known to influence growth and differentiation of target cells within the lung. Through the release of and activation of fibrosis-promoting cytokines and growth factors such as transforming growth factor-beta1, tumor necrosis factor-alpha, and insulin-like growth factors by MMPs, we propose that these metalloproteinases may be integral to the initiation and progression of pulmonary fibrosis.

Growth factors in idiopathic pulmonary fibrosis: relative roles

Treatment of idiopathic pulmonary fibrosis patients has evolved very slowly; the fundamental approach of corticosteroids alone or in combination with other immunosuppressive agents has had little impact on long-term survival. The continued use of corticosteroids is justified because of the lack of a more effective alternative. Current research indicates that the mechanisms driving idiopathic pulmonary fibrosis reflect abnormal, dysregulated wound healing within the lung, involving increased activity and possibly exaggerated responses by a spectrum of profibrogenic growth factors. An understanding of the roles of these growth factors, and the way in which they modulate events at cellular level, could lead to more targeted therapeutic strategies, improving patients' quality of life and survival.

Direct measurement of IGF-I and IGFBP-3 in bronchoalveolar lavage fluid from idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is characterized by the rearrangement of extracellular matrix and progressive increase in the amount of fibrotic tissue in the lung. IGF-I is a potent profibrogenic molecule and its bioavailability is dependent on at least 6 binding proteins called IGFBPs. Among these, IGFBP-3 is the most represented in serum and in different connective tissues. The purpose of this study was to identify and characterize IGFBP-3 in bronchoalveolar lavage (BAL) fluids. We studied 11 patients with IPF and 6 normal subjects by performing baseline pulmonary function test and BAL. IGF-I and IGFBP-3 were measured by RIA in BAL and serum. No significant differences were observed between serum IGF-I and IGFBP-3 from IPF patients and normal subjects. Instead, the direct measurement in BAL revealed a significant increase of IGF-I and IGFBP-3 in IPF patients compared to normal subjects. BAL IGF-I and IGFBP-3 concentrations were significantly related to inspiratory vital capacity (IVC) and carbon dioxide partial pressure (PaCO2): the higher the value of IVC and the lower the value of PaCO2, the higher the level of IGF-I and IGFBP-3. In conclusion, IGFBP3 and IGF-I could be important local mediators of IPF. Their direct measurement in BAL in IPF patients could be used as a clinical marker of the disease, since high levels of IGFBP-3 and IGF-I in BAL are associated to the initial phase of the disease.

Differential mRNA expression of insulin-like growth factor-1 splice variants in patients with idiopathic pulmonary fibrosis and pulmonary sarcoidosis

Insulin-like growth factor-1 (IGF-1) is a highly mitogenic polypeptide detectable in human lung. Using competitive reverse transcriptase/polymerase chain reaction (RT-PCR), expression of four IGF-1 transcripts was examined in bronchoalveolar lavage cells (BALC) from normal subjects, idiopathic pulmonary fibrosis (IPF), stage I/II (no fibrosis), and stage III/IV (confirmed fibrosis) pulmonary sarcoidosis patients, and fibroblast strains isolated from normal and IPF lungs. Transcripts studied were Class 1 and Class 2 (exons 1 or 2, respectively) with IGF-1Eb or IGF-1Ea (exons 5 or 6, respectively). Total IGF-1 expression was downregulated in BALC of both patients with IPF (p < 0.01) and patients with sarcoidosis (p < 0.04) compared with healthy subjects. In contrast, both constitutive (p < 0.003) and transforming growth factor-beta (TGF-beta)- induced (p < 0.02) IGF-1 expression was higher in fibrotic, compared with normal, fibroblasts. These changes were associated with differential expression of IGF-1 splice variants. Healthy subjects and sarcoidosis patients without fibrosis showed similar expression of Class 1/Class 2 and IGF-1Ea/IGF-1Eb. However, patients with fibrosis demonstrated discordant, increased relative abundance of Class 1 transcripts (p < 0.01). In parallel, all fibrosis patients failed to express Class 2, IGF-1Eb forms and sarcoidosis patients with fibrosis did not express the Class 1, IGF-1Eb variant either. Fibrotic fibroblasts expressed higher constitutive levels of Class 1, IGF-1Ea transcripts compared with normal fibroblasts. Class 2, IGF-1Eb forms were moderately expressed by fibroblasts only after stimulation with TGF-beta, which also further increased levels of Class 1, IGF-1Ea transcripts. Our findings suggest that transition from a healthy to a fibrotic phenotype occurs in association with a changing pattern of IGF-1 mRNA heterogeneity and leads us to hypothesize a potential role for specific IGF-1 variants in fibrogenesis.

Insulinlike growth factor-1 in lung transplants with obliterative bronchiolitis

Bronchiolitis obliterans syndrome (BOS) is the major complication limiting survival of lung transplant recipients (Tx patients). The mechanisms underlying this fibrotic process are not known. We assessed IGF-1 and IGFBP-3 expression, critical mediators in different models of pulmonary fibrosis, in nine Tx patients. Three of them developed a BOS at 8, 14, and 17 mo postgraft, respectively. Two of the remaining six displayed a recurrent cytomegalovirus (CMV) infection, and four are in stable condition. IGF-1 mRNA expression was quantitated by RT-PCR in cells from four to six BAL per patient performed during the first 6 mo postgraft. Contrasting with a constantly low expression of IGF-1 mRNA in BAL cells from the six patients without BOS, the three patients with BOS presented marked peaks of IGF-1 on two to five occasions during the study period. These peaks, 3- to 13-fold increased compared with values from the former patients, preceded the diagnosis of BOS by 7, 13, and 17 mo, respectively. On the other hand, IGFBP-3 was highly and exclusively expressed in the three patients with BOS, the mRNA as well as the gene product as demonstrated by Western blotting. Our data strongly argue for a role of IGF-1 and IGFBP-3 in the fibrotic process underlying BOS, and for their possible value as an early marker of this complication.

Expression of growth hormone-releasing factor, growth hormone, insulin-like growth factor-1 and its binding proteins in human lung

Reverse transcription PCR showed that mRNA encoding the neurohormones growth hormone-releasing factor (GRF) and GH, and its receptor GH-R, together with IGF-1 splice variants and IGFBPs are expressed by inflammatory cells found in the normal human airway. Unfractionated BALC moderately express GRF, GH and GH-R, IGFBP-2 to IGFBP-6, and IGFBP-rPl. In addition, BALC preferentially express the class 1 IGF-1Ea splice variant of the IGF-1 gene. A similar pattern of expression occurs in purified AM, except they do not appear to express GH-R. In marked contrast, AM precursor peripheral blood monocytes, do not express neuropeptides or IGF-1 and only express IGFBP-1, -4 and -6 and IGFBP-rP1. These data suggest that normal human inflammatory airway cells possess a powerful array of neurohormones and IGFBPs that are available for modulating local IGF-1 bioavailability in the lung.

Enhanced insulin-like growth factor binding protein-related protein 2 (Connective tissue growth factor) expression in patients with idiopathic pulmonary fibrosis and pulmonary sarcoidosis

Connective tissue growth factor is a recently described chemoattractant and fibroblast mitogen which, because of sequence homology and weak binding to insulin-like growth factor (IGF)-1, has been proposed as the eighth member of the IGF binding protein (IGFBP) superfamily, named IGFBP-related protein 2 (IGFBP-rP2). Previous studies have implicated IGFBP-rP2 in a number of heterogeneous fibrotic pathologies, including renal fibrosis, dermal scleroderma, and bleomycin-induced pulmonary fibrosis in mice. Because profibrogenic cytokines may be produced by inflammatory cells, we developed a multiplex competitive reverse transcription/polymerase chain reaction to quantify IGFBP-rP2 transcripts in bronchoalveolar lavage cells from healthy subjects and patients with idiopathic pulmonary fibrosis (IPF) and pulmonary sarcoidosis. IGFBP-rP2 messenger RNA expression was enhanced > 10-fold (P < 0.003) in patients with IPF; > 40-fold (P < 0.006) in stage I/II sarcoidosis patients, and > 90-fold (P < 0.005) in stage III/IV sarcoidosis patients by comparison with healthy nonsmoking control subjects. We suggest these increases are predominantly associated with lymphocyte- and neutrophil-driven IGFBP-rP2 production. These findings, together with previous reports implicating other IGFBPs in the pathogenesis of pulmonary fibrosis, suggest that the complex network of IGFBPs within the human lung is an important determinant of the outcome of the fibroproliferative response to injury.