Preventive and therapeutic effects of thymosin β4 N-terminal fragment Ac-SDKP in the bleomycin model of pulmonary fibrosis

In this study, the bleomycin model of pulmonary fibrosis was utilized to investigate putative anti-fibrotic activity of Ac-SDKP in vivo. Male CD-1 mice received intra-tracheal bleomycin (BLEO, 1 mg/kg) instillation in the absence or presence of Ac-SDKP (a dose of 0.6 mg/kg delivered intra-peritoneally on the day of BLEO treatment, d0, followed by bi-weekly additional doses). To evaluate therapeutic effects in a subset of mice, Ac-SDKP was administered one week after BLEO instillation (d7). Animals were sacrificed at one, two, or three weeks later. Measurement of fluid and collagen content in the lung, Broncho Alveolar Lavage Fluid (BALF) analysis, lung histology, immunohistochemistry (IHC), and molecular analysis were performed. Compared to BLEO-treated mice, animals that received also Ac-SDKP (at both d0 and d7) had significantly decreased mortality, weight loss, inflammation (edema, and leukocyte lung infiltration), lung damage (histological evidence of lung injury), and fibrosis (collagen histological staining and soluble collagen content in the lung) at up to 21 days. Moreover, IHC and quantitative RT-PCR results demonstrated a significant decrease in BLEO-induced IL-17 and TGF-β expression in lung tissue. Importantly, α-SMA expression, the hallmark of myofibroblast differentiation, was also decreased. This is the first report showing not only a preventive protective role of Ac-SDKP but also its significant therapeutic effects in the bleomycin model of pulmonary fibrosis, thus supporting further preclinical and clinical studies.

Effect of pirfenidone on cough in patients with idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive, fatal lung disease. In patients with IPF, cough is one of the most disabling symptoms and is an independent predictor of disease progression [1–3]. Cough in IPF is often non-responsive to antitussive therapy [4], and studies on cough are scarce and have unfortunately not yet resulted in effective treatments. Several observations suggest that pirfenidone, an anti-fibrotic drug, might decrease cough [5, 6]. We aimed to measure objectively the effect of pirfenidone on cough in patients with IPF and substantial cough. In addition, we assessed the effect of pirfenidone on subjective cough and quality of life (QoL) measures.

In patients with IPF, pirfenidone reduces objective 24-h cough counts and improves subjective measures of coughhttp://ow.ly/iiGu30f7Pea

When to start and when to stop antifibrotic therapies

Idiopathic pulmonary fibrosis (IPF) is characterised by progressive changes of the lung architecture causing cough and dyspnoea and ultimately leading to lung failure and death. Today, for the first time, two drugs that may reduce the inexorable progression of the disease are available, suggesting that treatment with specific drugs for IPF should be started as soon as diagnosis is made. This applies to any disease and particularly to IPF, which is marked by a 5-year survival comparable or even worse than many cancers. However, despite common sense and even worse, in spite of scientific data coming from clinical trials, post hoc analysis, long-term safety studies and real-life experiences, the question of when to start and when to stop treatment with antifibrotics is still debated. In IPF, particularly when the disease is diagnosed at an early stage, “wait and watch” behaviour is not rare to observe. This is largely due to the lack of awareness of both patients and clinicians regarding the progression of the disease and its prognosis. Another important issue is when treatment should be stopped. In general, there are two main reasons to stop a therapy: unbearable side-effects and/or lack of efficacy. According to current (although preliminary) evidence, antifibrotic drugs should not be discontinued except for safety issues.

Today, for the first time, we can use two effective drugs able to reduce the inexorable progression of IPFhttp://ow.ly/MCS930eOp2b

Unmet needs in the treatment of idiopathic pulmonary fibrosis-insights from patient chart review in five European countries

Background

Two antifibrotic drugs, pirfenidone and nintedanib, are approved by the European Medicines Agency and the US Food and Drug Administration for the treatment of idiopathic pulmonary fibrosis (IPF). In this analysis, treatment patterns of European patients with IPF were investigated to understand antifibrotic prescribing and identify unmet needs in IPF treatment practice.

Methods

Between February and March 2016, respiratory physicians from France, Germany, Italy, Spain, and the UK participated in an online questionnaire designed to collect information on IPF treatment patterns in patients under their care. Patients were categorized as treated (received approved antifibrotics) or untreated (did not receive approved antifibrotics, but may have received other unapproved therapies). Classification of IPF diagnosis (confirmed/suspected) and severity (‘mild’/‘moderate’/‘severe’) for each patient was based on the individual physician’s report. Patients’ perspectives were not recorded in this study.

Results

In total, 290 physicians responded to the questionnaire. Overall, 54% of patients with IPF did not receive treatment with an approved antifibrotic. More patients had a confirmed IPF diagnosis in the treated (84%) versus the untreated (51%) population. Of patients with a confirmed diagnosis, 40% did not receive treatment. The treated population was younger than the untreated population (67 vs 70 years, respectively; p ≤ 0.01), with more frequent multidisciplinary team evaluation (83% vs 57%, respectively; p ≤ 0.01). A higher proportion of untreated patients had forced vital capacity > 80% at diagnosis versus treated patients. Of patients with ‘mild’ IPF, 71% did not receive an approved antifibrotic versus 41% and 60% of patients with ‘moderate’ and ‘severe’ IPF, respectively.

Conclusions

Despite the availability of antifibrotic therapies, many European patients with confirmed IPF do not receive approved antifibrotic treatment. Importantly, there appears to be a reluctance to treat patients with ‘mild’ or ‘stable’ disease, and instead adopt a ‘watch and wait’ approach. More education is required to address diagnostic uncertainty, poor understanding of IPF and its treatments, and issues of treatment access. There is a need to increase physician awareness of the benefits associated with antifibrotic treatment across the spectrum of IPF severity.

Electronic supplementary material

The online version of this article (10.1186/s12890-017-0468-5) contains supplementary material, which is available to authorized users.

Diagnostic accuracy of a clinical diagnosis of idiopathic pulmonary fibrosis: an international case-cohort study

We conducted an international study of idiopathic pulmonary fibrosis (IPF) diagnosis among a large group of physicians and compared their diagnostic performance to a panel of IPF experts.A total of 1141 respiratory physicians and 34 IPF experts participated. Participants evaluated 60 cases of interstitial lung disease (ILD) without interdisciplinary consultation. Diagnostic agreement was measured using the weighted kappa coefficient (κ_w). Prognostic discrimination between IPF and other ILDs was used to validate diagnostic accuracy for first-choice diagnoses of IPF and were compared using the C-index.A total of 404 physicians completed the study. Agreement for IPF diagnosis was higher among expert physicians (κ_w=0.65, IQR 0.53-0.72, p<0.0001) than academic physicians (κ_w=0.56, IQR 0.45-0.65, p<0.0001) or physicians with access to multidisciplinary team (MDT) meetings (κ_w=0.54, IQR 0.45-0.64, p<0.0001). The prognostic accuracy of academic physicians with >20 years of experience (C-index=0.72, IQR 0.0-0.73, p=0.229) and non-university hospital physicians with more than 20 years of experience, attending weekly MDT meetings (C-index=0.72, IQR 0.70-0.72, p=0.052), did not differ significantly (p=0.229 and p=0.052 respectively) from the expert panel (C-index=0.74 IQR 0.72-0.75).Experienced respiratory physicians at university-based institutions diagnose IPF with similar prognostic accuracy to IPF experts. Regular MDT meeting attendance improves the prognostic accuracy of experienced non-university practitioners to levels achieved by IPF experts.

Neutrophil-To-Lymphocyte Ratio: An Emerging Marker Predicting Prognosis in Elderly Adults with Community-Acquired Pneumonia

OBJECTIVES

To explore the performance of the neutrophil-to-lymphocyte ratio (NLR), an index of systemic inflammation that predicts prognosis of several diseases, in a cohort of elderly adults with community-acquired pneumonia (CAP).

DESIGN

Prospective clinical study from January 2014 to July 2016.

SETTING

Unit of Internal Medicine, University of Catania, Catania, Italy.

PARTICIPANTS

Elderly adults admitted for CAP (N = 195).

MEASUREMENTS

Clinical diagnosis of CAP was defined as the presence of a new infiltrate on plain chest radiography or chest computed tomography associated with one or more suggestive clinical features such as dyspnea, hypo- or hyperthermia, cough, sputum production, tachypnea (respiration rate >20 breaths per minute), altered breath sounds on physical examination, hypoxemia (partial pressure of oxygen <60 mmHg), leukocytosis (white blood cell count >10,000/μL). Clinical examination, traditional tests such as Pneumonia Severity Index (PSI); Confusion, Urea, Respiratory rate, Blood pressure, aged 65 and older (CURB-65), and NLR were evaluated at admission. The accuracy and predictive value for 30-day mortality of traditional scores and NLR were compared.

RESULTS

NLR predicted 30-day mortality (P < .001) and performed better than PSI (P < .05), CURB-65, C-reactive protein, and white blood cell count (P < .001) to predict prognosis. No deaths occurred in participants with a NLR of less than 11.12. Thirty-day mortality was 30% in those with a NLR between 11.12% and 13.4% and 50% in those with a NLR between 13.4 and 28.3. All participants with a NLR greater than 28.3 died within 30 days.

CONCLUSIONS

These results would encourage early discharge of individuals with a NLR of less than 11.12, short-term in-hospital care for those with a NLR between 11.12 and 13.4, middle-term hospitalization for those with a NLR between 13.4 and 28.3, and admission to a respiratory intensive care unit for those with a NLR greater than 28.3.

Nanofat 2.0: experimental evidence for a fat grafting rich in mesenchymal stem cells

Different strategies have been developed in the last decade to obtain fat grafts as rich as possible of mesenchymal stem cells, so exploiting their regenerative potential. Recently, a new kind of fat grafting, called "nanofat", has been obtained after several steps of fat emulsification and filtration. The final liquid suspension, virtually devoid of mature adipocytes, would improve tissue repair because of the presence of adipose mesenchymal stem cells (ASCs). However, since it is probable that many ASCs may be lost in the numerous phases of this procedure, we describe here a novel version of fat grafting, which we call "nanofat 2.0", likely richer in ASCs, obtained avoiding the final phases of the nanofat protocol. The viability, the density and proliferation rate of ASCs in nanofat 2.0 sample were compared with samples of nanofat and simple lipoaspirate. Although the density of ASCs was initially higher in lipoaspirate sample, the higher proliferation rate of cells in nanofat 2.0 virtually filled the gap within 8 days. By contrast, the density of ASCs in nanofat sample was the poorest at any time. Results show that nanofat 2.0 emulsion is considerably rich in stem cells, featuring a marked proliferation capability.

Cough in idiopathic pulmonary fibrosis

Many patients with idiopathic pulmonary fibrosis (IPF) complain of chronic refractory cough. Chronic cough is a distressing and disabling symptom with a major impact on quality of life. During recent years, progress has been made in gaining insight into the pathogenesis of cough in IPF, which is most probably "multifactorial" and influenced by mechanical, biochemical and neurosensory changes, with an important role for comorbidities as well. Clinical trials of cough treatment in IPF are emerging, and cough is increasingly included as a secondary end-point in trials assessing new compounds for IPF. It is important that such studies include adequate end-points to assess cough both objectively and subjectively. This article summarises the latest insights into chronic cough in IPF. It describes the different theories regarding the pathophysiology of cough, reviews the different methods to assess cough and deals with recent and future developments in the treatment of cough in IPF.

Translation and validation of the King's Brief Interstitial Lung Disease (K-BILD) questionnaire in French, Italian, Swedish, and Dutch

No disease-specific instruments exist in Dutch, French, Italian, and Swedish to measure health status in idiopathic pulmonary fibrosis (IPF) and other interstitial lung diseases (ILDs). The King's Brief Interstitial Lung Disease (K-BILD) is a 15-item validated questionnaire assessing health status in patients with ILD. The aim of this study was to translate and validate the K-BILD to French, Italian, Swedish, and Dutch versions. The K-BILD was translated following a forward-backward multistep procedure and tested in structured patient interviews. Subsequently, 195 outpatients with ILD were asked to complete K-BILD, St. George's Respiratory Questionnaire (SGRQ), and Euroqol EQ-5D-5L (EQ5D), twice, 2 weeks apart. Internal consistency, concurrent validity, and repeatability were determined. No major difficulties occurred in the translation processes. The K-BILD was considered comprehensible and relevant by patients. One hundred seventy-six patients (108 IPF and 68 other ILDs) completed the translated K-BILD. Internal consistency was good for all K-BILD modules (Cronbach's α 0.70-0.93). Concurrent validity of K-BILD was strong compared with SGRQ ( r = -0.86) and EQ5D ( r = 0.68), low with transfer capacity of the lung for carbon monoxide corrected for hemoglobin ( r = 0.33) and with forced vital capacity ( r = 0.35). The K-BILD and its domains were repeatable over 2 weeks; intraclass correlation coefficients were 0.86-0.93 ( n = 159). Known groups validity showed K-BILD was able to discriminate between patients based on severity of disease. K-BILD's validity and reliability for patients with IPF was similar to that of other ILDs. The French, Italian, Swedish, and Dutch translated K-BILD questionnaires were well-received by patients and demonstrated excellent validity comparable to the original English K-BILD.

Rare pulmonary diseases and orphan drugs: where do we stand and where are we going to?

Rare diseases are a major problem for the patients who suffer from them, for their families and for selected specialists involved in their management. In addition, they cause economic, social and public health problems that should be acknowledged and discussed by the medical and scientific community. Because of the rarity of these illnesses, the experience of most physicians is usually limited to a few cases. Nevertheless, the essential steps in the diagnosis and management of a patient who is suspected to have, for example, an interstitial lung disease or pulmonary hypertension, should be common knowledge, as these diseases are uncommon, but not, in fact, exceedingly rare [1–3]. Furthermore, rare presentations of frequent lung diseases (e.g. rare thoracic cancers, severe asthma, and emphysema with α₁-antitrypsin deficiency) and the most typical rare pulmonary diseases can share similar aspects, both in research and in their clinical management [4].

Updates on rare pulmonary diseases from the 6th International Meeting on Pulmonary Rare Diseases and Orphan Drugshttp://ow.ly/PYUCC

New perspectives on management of idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive parenchymal lung disease characterized by a median survival of 3-5 years following diagnosis. The diagnosis is based on clinical, radiological and histopathological evaluation. Therefore, a multidisciplinary team is needed to reach the correct diagnosis. For a long time, supportive care and lung transplantation in selected cases, have been considered the only possible treatments for IPF. In the last decade many studies have investigated IPF pathogenesis, leading to an improved knowledge of the mechanisms underlying the disease and to the approval of two new drugs for IPF treatment (pirfenidone and nintedanib). The therapeutic approach of IPF cannot be limited to the administration of antifibrotic drugs, but it is necessary for improving the quality of life of patients and for facilitating, as far as possible, the performance of normal daily activities and relationships. IPF patients are also afflicted by disease-related complications such as gastroesophageal reflux, pulmonary hypertension, acute exacerbations and an increased risk of developing lung cancer. The clinician who treats IPF patients, should also treat these possible complications to slow disease progression, thus maintaining the possibility of a pulmonary transplantation.

Qualitative European survey of patients with idiopathic pulmonary fibrosis: patients' perspectives of the disease and treatment

Background

‘Living with IPF and an exploration of Esbriet® – a new treatment’ was an exploratory, qualitative, real-world survey of European patients with idiopathic pulmonary fibrosis (IPF) who were receiving treatment with pirfenidone prior to its commercial availability. The aim of the survey was to probe the impact of IPF on patients’ quality of life; the role of healthcare professionals and caregivers; the information needs of both patients and their caregivers; and patients’ perceptions of pirfenidone as a new treatment option for IPF.

Methods

Patients from the UK, Germany and Italy, with a diagnosis of IPF (duration >3 months), who were being treated with pirfenidone, were recruited from patient support groups, specialist centres and advocacy groups. Semi-structured, qualitative, in-depth patient interviews of 1-h duration were conducted by an independent researcher. Patients were initially asked about their experiences of living with IPF and then prompted to describe their experiences of taking pirfenidone. Techniques utilised included: the bubble-speech technique; the icon cards projective exercise; and the free association exercise. All interviews were transcribed and analysed by an independent researcher.

Results

Forty-five patients (71 % male) were interviewed (mean age 68.5 years; mean time since diagnosis 3.5 years); 87 % of patients reported that diagnosis took >1 year. Patients reported that IPF had a significant physical and emotional impact on their quality of life. The beneficial role played by caregivers and interstitial lung disease specialist nurses (where available) was specifically highlighted. Although most patients were keen for information on IPF, this was often of poor quality, out of date, or in English only. Patients’ perceptions of pirfenidone were largely positive and associated with ‘hope’ but were also influenced by the level of side effects experienced.

Conclusions

This survey highlights the impact of IPF on patients’ lives, and the need to adequately support both patients and their caregivers. These findings demonstrate the value of seeking patients’ perspectives of a chronic disease such as IPF and how this information can be used to guide improvements in care, to best support the needs of patients with this devastating condition.

Electronic supplementary material

The online version of this article (doi:10.1186/s12890-016-0171-y) contains supplementary material, which is available to authorized users.

Levels of circulating endothelial cells are low in idiopathic pulmonary fibrosis and are further reduced by anti-fibrotic treatments

BACKGROUND

It has been suggested that circulating fibrocytes and endothelial cells actively participate in the intense remodelling of the pulmonary vasculature in patients with idiopathic pulmonary fibrosis (IPF). Indeed, fibrotic areas exist that have fewer blood vessels, whereas adjacent non-fibrotic tissue is highly vascularized. The number of circulating endothelial cells (CEC) and endothelial progenitor cells (EPC) might reflect the balance between vascular injury and repair. Thus, fibrocytes as well as endothelial cells could potentially be used as biomarkers of disease progression and treatment outcome.

METHODS

Peripheral blood samples were collected from 67 patients with a multidisciplinary diagnosis of IPF and from 45 age-matched and sex-matched healthy volunteers. Buffy coat was isolated according to standard procedures and at least 20 million cells were stained with different monoclonal antibodies for the detection of CEC, EPC and circulating fibrocytes. For the detection of CEC and EPC, cells were stained with anti-CD45, anti-CD34, anti-CD133, anti-CD14, anti-CD309 and with the viability probe Far-Red LIVE/DEAD. For the detection of circulating fibrocytes, cells were first stained with LIVE/DEAD and the following monoclonal antibodies: anti-CD3, anti-CD19, anti-CD45, anti-CD34 and anti-CD14, then cells were fixed, permeabilized and stained with fluorochrome-conjugated anti-collagen I monoclonal antibodies.

RESULTS

Patients with IPF displayed almost undetectable levels of circulating fibrocytes, low levels of CEC, and normal levels of EPC. Patients treated with nintedanib displayed higher levels of CEC, but lower levels of endothelial cells expressing CD309 (the type II receptor for vascular endothelial growth factor). Treatment with both nintedanib and pirfenidone reduced the percentage of CEC and circulating fibrocytes.

CONCLUSIONS

Levels of CEC were reduced in patients with IPF as compared to healthy individuals. The anti-fibrotic treatments nintedanib and pirfenidone further reduced CEC levels. These findings might help explain the mechanism of action of these drugs and should be explored as predictive biomarkers in IPF.

Idiopathic pulmonary fibrosis and cancer: do they really look similar?

BACKGROUND

The aim of this opinion article is to understand to what extent idiopathic pulmonary fibrosis (IPF) can be considered, in its clinical and pathogenic features, similar to cancer. Indeed, IPF has common risk factors with cancer, a low survival, and, most importantly, epigenetic and genetic alterations, abnormal expression of microRNAs, cellular and molecular aberrances, and the activation of similar signalling pathways.

DISCUSSION

The pathogenic link between the two diseases may have a number of practical consequences. It may improve our understanding of IPF drawing on cancer biology knowledge. In addition, the recognition of similar pathogenic pathways may also encourage the use of cancer drugs for the treatment of IPF. Nintedanib, an inhibitor of tyrosine kinase receptors initially developed for cancer, has been recently approved for the treatment of IPF thanks to the observation that these receptors are also abnormally activated in IPF. The vision of IPF as a cancer-like disease may improve our understanding of the pathogenesis of this disease also opening new scenarios for repositioning cancer drugs for IPF. In addition, it may increase the level of awareness towards this dreadful disease at the public, political, and healthcare level.

IPF, comorbidities and management implications

Idiopathic pulmonary fibrosis (IPF) is a complex disease that is associated with various respiratory and non-respiratory comorbidities. The most common comorbidity is cardiovascular disease (CVD), which increases in incidence with increasing duration of IPF and is associated with a higher risk of mortality. The direction of causality between CVD and IPF is unclear. There is evidence that IPF is associated with a prothrombotic state; however, warfarin is not beneficial in IPF patients. Lung cancer is another common comorbidity, being present in more than 50% of IPF patients at 10 years after diagnosis. IPF and lung cancer share several risk factors and pathogenic pathways and also show a similar anatomic distribution; this can make radiological diagnosis difficult. As with CVD, lung cancer in IPF patients is associated with a significantly worse prognosis and treatment options are limited. Surgery, chemotherapy, and radiotherapy have all been associated with an increased risk of morbidity and mortality. However, treatment may be considered in selected patients with less advanced cancer and less advanced IPF. Emphysema may occur in patients with IPF and is believed to represent a distinct clinical syndrome, known as the combined pulmonary fibrosis and emphysema (CPFE) syndrome. CPFE has a strong male predominance, is strongly linked with smoking, and has distinct radiographic features. CPFE is also associated with a very high frequency of pulmonary hypertension, which is associated with a poor prognosis. There are no specific treatments for CPFE and evaluation of IPF therapies in CPFE patients is urgently needed.

Effects of thymosin β4 and its N-terminal fragment Ac-SDKP on TGF-β-treated human lung fibroblasts and in the mouse model of bleomycin-induced lung fibrosis

Thymosin β4 (Tβ4) and its amino-terminal fragment comprising N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP) have been reported to act as anti-inflammatory and anti-fibrotic agents in vitro and in vivo. In recent papers, we have shown that Tβ4 exerts a widely protective role in mice treated with bleomycin, and in particular, we have demonstrated its inhibitory effects on both inflammation and early fibrosis.

OBJECTIVES

In this study, the putative anti-proliferative and anti-fibrogenic effects of Tβ4 and Ac-SDKP were evaluated in vitro. In addition, the effects of Tβ4 up to 21 days were evaluated in the bleomycin mouse model of lung fibrosis.

METHODS

We utilized both control and TGF-β-stimulated primary human lung fibroblasts isolated from both idiopathic pulmonary fibrosis (IPF) and control tissues. The in vivo effects of Tβ4 were assessed in CD1 mice treated with bleomycin.

RESULTS

In the in vitro experiments, we observed significant anti-proliferative effects of Ac-SDKP in IPF fibroblasts. In those cells, Ac-SDKP significantly inhibited TGF-β-induced α-SMA and collagen expression, hallmarks of fibroblast differentiation into myofibroblasts triggered by TGF-β. In vivo, despite its previously described protective role in mice treated with bleomycin at 7 days, Tβ4 failed to prevent fibrosis induced by the drug at 14 and 21 days.

CONCLUSION

We conclude that, compared to Tβ4, Ac-SDKP may have greater potential as an anti-fibrotic agent in the lung. Further in vivo experiments are warranted.

The role of tyrosine kinases in the pathogenesis of idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive lung disease with a median survival time from diagnosis of 2-3 years. Although the pathogenic pathways have not been fully elucidated, IPF is believed to be caused by persistent epithelial injury in genetically susceptible individuals. Tyrosine kinases are involved in a range of signalling pathways that are essential for cellular homeostasis. However, there is substantial evidence from in vitro studies and animal models that receptor tyrosine kinases, such as the platelet-derived growth factor receptor, vascular endothelial growth factor receptor and fibroblast growth factor receptor, and non-receptor tyrosine kinases, such as the Src family, play critical roles in the pathogenesis of pulmonary fibrosis. For example, the expression and release of tyrosine kinases are altered in patients with IPF, while specific tyrosine kinases stimulate the proliferation of lung fibroblasts in vitro. Agents that inhibit tyrosine kinases have shown anti-fibrotic and anti-inflammatory effects in animal models of pulmonary fibrosis. Recently, the tyrosine kinase inhibitor nintedanib has shown positive results in two phase III trials in patients with IPF. Here, we summarise the evidence for involvement of specific tyrosine kinases in the pathogenesis of IPF and the development of tyrosine kinase inhibitors as treatments for IPF.

In vitro antiproliferative effect of trastuzumab (Herceptin(®)) combined with cetuximab (Erbitux(®)) in a model of human non-small cell lung cancer expressing EGFR and HER2

Lung cancer is the leading cause of cancer death. For this reason, new therapies are needed for the treatment of this devastating disease. In this study, we investigated the effects of combining cetuximab and the trastuzumab on the growth of a model of human non-small cell lung carcinoma cell line (A549). The results were compared with those obtained from a human lung squamous carcinoma cell line (NCI-H226). Both cell lines were treated with cetuximab and trastuzumab, alone or in combination, at various concentrations, for 24, 48 and 72 h. Cell proliferation was measured by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. EGFR and HER-2 mRNA expression was detected by reverse transcription polymerase chain reaction, and the gene amplification status of receptors was evaluated by fluorescence in situ hybridisation. The colorimetric proliferation assay showed that trastuzumab combined with cetuximab significantly inhibited A549 cells at a dose of 40 μg/ml after 72 h of treatment (p < 0.05), while no time-dose dependent inhibition was observed in NCI-H226 cells. The combined treatment influenced both levels of EGFR and HER-2 mRNA in A549 cells and only EGFR mRNA levels in NCI-H226 cells. Fluorescence in situ hybridisation showed that both cell lines were aneuploid for the two genes with equally increased EGFR and CEN7 signals, as well as HER-2 and CEN17 signals, indicating a condition of polysomy without amplification. The preliminary results of this study encourage further investigations to elucidate the downstream events involved and to understand how these mechanisms influence non-small cell lung cancers growth.

Idiopathic pulmonary fibrosis: an update

Idiopathic pulmonary fibrosis (IPF) is the most common and lethal form of idiopathic interstitial pneumonia. The disease, which occurs primarily in middle-aged and older adults, is thought to arise following an aberrant reparative response to alveolar epithelial cell injury characterized by secretion of excessive amounts of extracellular matrix components, resulting in scarring of the lung, architectural distortion, and irreversible loss of function. A complex interplay between environmental and host factors is thought to contribute to the development of the disease, although the cause of IPF remains elusive and its pathogenesis incompletely understood. Over the last decade, disease definition and diagnostic criteria have evolved significantly, and this has facilitated the design of a number of high-quality clinical trials evaluating novel therapeutic agents for IPF. This massive effort of the medical and industry community has led to the identification of two compounds (pirfenidone and nintedanib) able to reduce functional decline and disease progression. These promising results notwithstanding, IPF remains a major cause of morbidity and mortality and a largely unmet medical need. A real cure for this devastating disease has yet to emerge and will likely consist of a combination of drugs targeting the plethora of pathways potentially involved in disease pathogenesis.

Anti-inflammatory and antifibrotic effects of resveratrol in the lung

Resveratrol, a natural polyphenolic molecule with several biological activities, is a well recognized anti-oxidant, anti-aging and cancer chemopreventive agent. Moreover, resveratrol anti-inflammatory and antifibrotic properties have been demonstrated both in vitro and in different animal models of inflammatory pathologies, including bowel and liver diseases. We review the evidence of resveratrol protective role in respiratory diseases such as acute lung injury, asthma, chronic obstructive pulmonary disease and lung fibrosis. We conclude that resveratrol and its derivatives may act as a therapeutic agents in respiratory diseases and pertinent clinical trials should be performed.

Protein profile of exhaled breath condensate determined by high resolution mass spectrometry

A method based on liquid chromatography/high resolution tandem mass spectrometry coupled with electrophoretic separation, for determination and relative quantification of the protein composition of exhaled breath condensate (EBC), was developed. Application of the procedure to a sample of EBC, pooled from nine healthy subjects, resulted in the identification of 167 unique gene products, 113 of which not previously reported in EBC samples. The abundance of the protein identified was estimated by means of the exponentially modified protein abundance index protocol (emPAI). Cytokeratins were by far the most abundant proteins in EBC samples. Many of the identified proteins were associated with multiple cellular location with cytoplasm constituting the largest group. Cytosol, nucleus, membrane, cytoskeleton and extracellular were other abundantly represented locations. No amylase was detected, suggesting the absence of saliva protein contamination. The profile obtained represents the most comprehensive protein characterization of EBC so far reported and demonstrates that this approach provides a powerful tool for investigating the protein profile of EBC samples. Compared with analogous investigations, this study also shows that the protein profile of EBC is strongly affected by the sampling method adopted.

Combination therapy: the future of management for idiopathic pulmonary fibrosis?

Findings from recently published placebo-controlled trials in idiopathic pulmonary fibrosis have established that pirfenidone and nintedanib prevent about 50% of the decline in forced vital capacity typically seen in this disease; future trials are therefore unlikely to use placebo as a control group for ethical reasons. Future clinical assessment will probably include add-on trials in which a new drug is combined with an intervention with established efficacy; this development is in turn likely to herald the use of combination regimens in clinical practice. Personalised medicine (the selection of monotherapies on the basis of individualised biomarker signal) is an intrinsically attractive alternative approach, but is unlikely to be useful in routine management of idiopathic pulmonary fibrosis in the medium-term future because of the complex nature of the disease's pathogenesis. In this Personal View, we review the pleiotropic nature of disease pathogenesis in idiopathic pulmonary disease, the use of combination regimens in other selected chronic lung diseases, and the conceptual basis for combination therapies in interstitial lung disorders other than idiopathic pulmonary fibrosis. On the basis of these considerations, and the emergence of data from add-on trials, we believe that the future of management for idiopathic pulmonary fibrosis lies in the development of combination regimens.

Altered surfactant homeostasis and alveolar epithelial cell stress in amiodarone-induced lung fibrosis

Amiodarone (AD) is a highly efficient antiarrhythmic drug with potentially serious side effects. Severe pulmonary toxicity is reported in patients receiving AD even at low doses and may cause interstitial pneumonia as well as lung fibrosis. Apoptosis of alveolar epithelial type II cells (AECII) has been suggested to play an important role in this disease. In the current study, we aimed to establish a murine model of AD-induced lung fibrosis and analyze surfactant homeostasis, lysosomal, and endoplasmic reticulum (ER) stress in this model. AD/vehicle was instilled intratracheally into C57BL/6 mice, which were sacrificed on days 7, 14, 21, and 28. Extent of lung fibrosis development was assessed by trichrome staining and hydroxyproline measurement. Cytotoxicity was assessed by lactate dehydrogenase assay. Phospholipids (PLs) were analyzed by mass spectrometry. Surfactant proteins (SP) and markers for apoptosis, lysosomal, and ER stress were studied by Western blotting and immunohistochemistry. AECII morphology was evaluated by electron microscopy. Extensive lung fibrosis and AECII hyperplasia were observed in AD-treated mice already at day 7. Surfactant PL and SP accumulated in AECII over time. In parallel, induction of apoptosis, lysosomal, and ER stress was encountered in AECII of mice lungs and in MLE12 cells treated with AD. In vitro, siRNA-mediated knockdown of cathepsin D did not alter the AD-induced apoptotic response. Our data suggest that mice exposed to intratracheal AD develop severe pulmonary fibrosis, exhibit extensive surfactant alterations and cellular stress, but AD-induced AECII apoptosis is not mediated primarily via cathepsin D.

Clinical and radiological features of idiopathic interstitial pneumonias (IIPs): a pictorial review

OBJECTIVES

To illustrate the clinical and radiological features of idiopathic interstitial pneumonias (IIPs), according to the American Thoracic Society (ATS)/European Respiratory Society (ERS) classification updated in 2013.

METHODS

IIPs include a subset of diffuse and restrictive lung diseases, resulting from damage to the parenchyma characterised by inflammation and fibrosis of the interstitium. Classification into major and rare IIPs is based on the 2013 ATS/ERS committee.

RESULTS

The diagnosis of idiopathic pulmonary fibrosis (IPF) needs to exclude other well-known causes of interstitial lung diseases. According to the 2011 evidence-based guidelines, usual interstitial pneumonia (UIP) can be diagnosed by HRCT when all criteria are fulfilled. Non-specific interstitial pneumonia (NSIP) is characterised by patchy ground-glass opacities and irregular linear/reticular opacities. The imaging patterns of respiratory bronchiolitis associated-interstitial lung disease (RB-ILD) and desquamative interstitial pneumonia (DIP) show centrolobular nodules and ground-glass opacities. Cryptogenic organising pneumonia (COP) consists of patchy peripheral or peribronchial consolidations, while ground-glass opacities are typically associated with diffuse lung consolidation, evolving to fibrosis, in acute interstitial pneumonia (AIP). Rare IIPs include lymphoid interstitial pneumonia and idiopathic pleuro-parenchymal fibroelastosis (IPPFE).

CONCLUSIONS

The knowledge of IIP imaging features on HRCT images help radiologists in diagnosis. Moreover, the overlap of imaging features needs a multidisciplinary approach.

TEACHING POINTS

• UIP findings are reticulations, bronchiectasis, honeycombing and absence of inconsistent features. • Bilateral patchy ground-glass areas represent the most encountered features in NSIP. • Poorly defined centrilobular nodules are typical of RB-ILD, whereas a ground-glass appearance is typical of DIP. • HRCT features of COP include characteristic peripheral or peribronchial patchy consolidations. • Rare IIPs include idiopathic LIP and idiopathic pleuro-parenchymal fibroelastosis (PPFE).

Common pathways in idiopathic pulmonary fibrosis and cancer

Idiopathic pulmonary fibrosis (IPF) is marked by a very disappointing survival rate and still represents a clinical dilemma. According to the current pathogenic hypothesis, chronic damage of the alveolar epithelium is followed by abnormal tissue repair and impairment of the alveolar structure. This process is driven by pathogenic events very similar to cancer, including epigenetic and genetic changes, altered response to regulatory signals, abnormal expression of microRNAs and activation of specific signalling pathways. IPF also resembles cancer with regard to its poor response to medical treatment and prognosis, which is very often worse than many cancers. We have hypothesised that IPF might be assimilated to a neoproliferative disorder of the lung. Viewing IPF as a cancer-like disease may satisfy the need for a better understanding of the pathogenesis of IPF by exploiting the large amount of knowledge that cancer biology evokes. The recognition of common pathogenic pathways between the two diseases may stimulate new clinical trials with cancer drugs, different drug combinations and different lines of drugs, as already experimented in oncology. Moreover, the concept of IPF as a cancer-like disorder may improve the attention given to this dreadful disease on a public, political and healthcare level.

Pirfenidone in idiopathic pulmonary fibrosis: expert panel discussion on the management of drug-related adverse events

Pirfenidone is currently the only approved therapy for idiopathic pulmonary fibrosis, following studies demonstrating that treatment reduces the decline in lung function and improves progression-free survival. Although generally well tolerated, a minority of patients discontinue therapy due to gastrointestinal and skin-related adverse events (AEs). This review summarizes recommendations based on existing guidelines, research evidence, and consensus opinions of expert authors, with the aim of providing practicing physicians with the specific clinical information needed to educate the patient and better manage pirfenidone-related AEs with continued pirfenidone treatment. The main recommendations to help prevent and/or mitigate gastrointestinal and skin-related AEs include taking pirfenidone during (or after) a meal, avoiding sun exposure, wearing protective clothing, and applying a broad-spectrum sunscreen with high ultraviolet (UV) A and UVB protection. These measures can help optimize AE management, which is key to maintaining patients on an optimal treatment dose.

Effect of pirfenidone on proliferation, TGF-β-induced myofibroblast differentiation and fibrogenic activity of primary human lung fibroblasts

Pirfenidone is an orally active small molecule that has been shown to inhibit the progression of fibrosis in animal models and in patients with idiopathic pulmonary fibrosis. Although pirfenidone exhibits well documented antifibrotic and antiinflammatory activities, in vitro and in vivo, its molecular targets and mechanisms of action have not been elucidated. In this study, we investigated the effects of pirfenidone on proliferation, TGF-β-induced differentiation and fibrogenic activity of primary human lung fibroblasts (HLFs). Pirfenidone reduced fibroblast proliferation and attenuated TGF-β-induced α-smooth muscle actin (SMA) and pro-collagen (Col)-I mRNA and protein levels. Importantly, pirfenidone inhibited TGF-β-induced phosphorylation of Smad3, p38, and Akt, key factors in the TGF-β pathway. Together, these results demonstrate that pirfenidone modulates HLF proliferation and TGF-β-mediated differentiation into myofibroblasts by attenuating key TGF-β-induced signaling pathways.

Thymosin β4 reduces IL-17-producing cells and IL-17 expression, and protects lungs from damage in bleomycin-treated mice

Thymosin β4 (Tβ4) is a highly conserved peptide with immunomodulatory properties. In this research we investigated the effects of Tβ4 on the bleomycin-induced lung damage in CD-1 mice and the changes in the number of IL-17-producing cells as well as the IL-17 expression in the lung. Male CD-1 mice were treated with bleomycin (1mg/kg) in the absence or the presence of Tβ4 (6mg/kg delivered intra-peritoneally on the day of bleomycin treatment and for 2 additional doses). After sacrifice one week later, lung histology, measurement of collagen content of the lung, Broncho Alveolar Lavage Fluid (BALF) analysis, evaluation of IL17-producing cells in the blood as well as RT-PCR and IHC in the lung tissue were performed. As expected, bleomycin-induced inflammation and lung damage were substantially reduced by Tβ4 treatment in CD-1 mice, as shown by the significant reduction of (i) leukocytes in BALF, (ii) histological evidence of the lung damage, and (iii) total collagen content in the lung. Importantly, the bleomycin-induced increase in the number of IL17-producing cells in the blood was significantly blocked by Tβ4. Accordingly, IHC and RT-PCR results demonstrated that Tβ4 substantially inhibited bleomycin-induced IL-17 over-expression in the lung tissue. This is the first report showing that a decreased amount of IL17-producing cells and inhibited IL-17 expression in the lung with Tβ4 treatment correlate with its anti-inflammatory and anti-fibrotic effects.

Differentiation of human adipose stem cells into neural phenotype by neuroblastoma- or olfactory ensheathing cells-conditioned medium

Olfactory ensheathing cells (OECs) are known to be capable of continuous neurogenesis throughout lifetime and are a source of multiple trophic factors important in central nervous system regeneration. B104 neuroblastoma cells are recognized to induce differentiation of neural stem cells into oligodendrocyte precursor cells. Therefore, the aim of this study was to verify if conditioned medium (CM) obtained from OECs or B104 cells was capable of inducing differentiation of adipose tissue-derived mesenchymal stem cells (AT-MSCs) to a neuronal phenotype. In order to this goal, immunocytochemical procedures and flow cytometry analysis were used and some neural markers, as nestin, protein gene product 9.5 (PGP 9.5), microtubule-associated protein 2 (MAP2), glial fibrillary acidic protein (GFAP), and neuron cell surface antigen (A2B5) were examined 24 h and 7 days after the treatment. The results showed that both OECs- or B104-CM treated AT-MSCs express markers of progenitor and mature neurons (nestin, PGP 9.5 and MAP2) in time-dependent manner, display morphological features resembling neuronal cells, and result negative for GFAP and A2B5, astrocyte and oligodendrocyte markers, respectively. This study demonstrated that AT-MSCs can be influenced by the environment, indicating that these cells can respond to environmental cues also versus a neuronal phenotype.

Human lung fibroblasts increase CD4(+)CD25(+)Foxp3(+) T cells in co-cultured CD4(+) lymphocytes

Aim of this study was to evaluate functional modifications induced by human lung fibroblasts in co-cultured CD4(+) T lymphocytes. CD4(+) T cells, resting or stimulated with ionomycin/PMA for 6h, were co-cultured with fibroblasts isolated from pulmonary biopsies, in contact or separated by a semi-permeable membrane. The expression of CD25, CTLA-4, TGF-β, IFNγ, IL-2, IL-4, IL-10 and Foxp3 was evaluated by flow cytometric analysis. Fibroblasts induced a significant increment in CD25(+) cells in co-cultured activated CD4(+) T lymphocytes separated by a membrane. Moreover, fibroblasts treatment with a COX2 inhibitor abrogated the increment in CD25(+) cells whereas exogenous PGE2 restored it. The CD25(+) subpopulation was characterized by increased presence of Fox-P3, CTLA-4, IL-10 and TGF-β positive cells while IFN-γ and IL-2 positive cells were diminished. Proliferative response of CD4(+) to the anti CD3/CD28-Abs was abrogated in CD4(+) co-cultured with fibroblasts thus demonstrating a suppressive feature of the expanded CD25(+) subpopulation.

Gastro-oesophageal reflux and idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is the most common of the idiopathic interstitial pneumonias. There is evidence of an increased prevalence of acid gastro-oesophageal reflux disease (GERD) in patients with IPF. Recent articles have focused on the potential role of chronic silent microaspiration in the pathogenesis of IPF. Aspiration in defined as the inhalation of gastric content into the larynx and lower respiratory tract. The reported use of GERD medications is an independent predictor of longer survival time in patients with IPF. These findings further support the hypothesis that GERD and chronic micro-aspiration may play important roles in the pathobiology of IPF.

Mapping the future for pulmonary fibrosis: report from the 17th International Colloquium on Lung and Airway Fibrosis

Pulmonary fibrosis is the ultimate outcome of various interstitial lung diseases, many of which have a dismal prognosis. Pulmonary fibrosis, therefore, represents a critical unmet medical need. Progress in research over the past 30 years has been encouraging. This work, which has been funded by governments, charitable trusts, industries and patient groups, has resulted in clinical trials testing novel drugs, giving hope to patients. In late September 2012, representatives from academia, industry and funding agencies met at the 17th International Colloquium on Airway and Lung Fibrosis to discuss state-of-the-art knowledge of pulmonary fibrosis. This manuscript summarises the outcomes of the meeting, highlighting the most relevant results and discoveries. It also attempts to provide a roadmap for future studies. It is hoped that such a roadmap may help interested parties to generate new research, which will be vital to continued progress. We are encouraged by the commitment expressed by all participants at this meeting and the shared vision of promoting future progress through international collaboration, the pooling of valuable resources, and the involvement of a new generation of physicians and scientists.

Comparative proteome analysis of lung tissue from patients with idiopathic pulmonary fibrosis (IPF), non-specific interstitial pneumonia (NSIP) and organ donors

Among the idiopathic interstitial pneumonias (IIP), the two entities IPF and NSIP seem to be clinically related, but NSIP has a better outcome. The proteomic signatures which distinguish NSIP from IPF remain still elusive. We therefore performed comparative proteomic analysis of peripheral lung tissue from patients with sporadic IPF (n=14) and fibrotic NSIP (fNSIP, n=8) and organ donors (Controls, n=10), by using the 2-dimensional DIGE technique and MALDI-TOF-MS. The study revealed that the proteomic profiles of IPF and fNSIP were quite similar. Among the upregulated proteins in IPF and fNSIP were stress-induced genes involved in the ER stress-pathway, whereas downregulated proteins in IPF and fNSIP included antiapoptotic factors and antifibrotic molecules. The comparison fNSIP versus IPF indicated upregulation of subunits of the proteasome activator complex and antioxidant enzymes of the peroxiredoxin family. We conclude, that only few protein expression changes exist between IPF and fNSIP, and that epithelial ER- and oxidative stress play a major role in the pathogenesis of both diseases. In contrast to IPF, intracellular clearance of ROS and misfolded protein carbonyls seem to be enhanced in fNSIP due to enhanced expression of antioxidant acting proteins, and may explain the better outcome and survival in patients with fNSIP.

BIOLOGICAL SIGNIFICANCE

IPF and fibrotic NSIP (fNSIP) belong to the idiopathic interstitial pneumonias and are usually fatal, but fNSIP has a better outcome. In order to identify molecular mechanisms and differences between IPF and fNSIP, we herein present results of a comparative proteome analysis of IPF, fNSIP and control lung tissue. Our data including validation experiments suggest that ER stress and a general stress-response as well as the decline of antioxidant capacity in alveolar epithelium is key in the pathogenesis of IPF and fNSIP. In addition, we could observe a signature of an increased alveolar epithelial protection against oxidative and ER-stress in fNSIP as compared to IPF, which could help to explain the better outcome of fNSIP patients.

Interferon-γ and interleukin-17 production from PPD-stimulated PBMCss of patients with pulmonary tuberculosis

PURPOSE

The purpose of this study was to evaluate Interferon (IFN)-γ and Interleukin(IL)-17 profiles in patients with different clinical presentations of pulmonary tuberculosis (TB) and to compare them with those of tuberculin-negative and tuberculin-reactive healthy controls

METHODS

Peripheral blood mononuclear cells (PBMCss), isolated from patients (n=52) and controls (n=30), were stimulated ex vivo with purified protein derivative (PPD) and IFN-γ and IL-17 levels in the supernatant were measured.

RESULTS

At baseline, PBMCss from patients with TB released a significantly lower amount of IL-17 (p=0.043) than PBMCss from healthy controls, whereas IFN-γ levels were similar in the two groups. After PPD stimulation, a significant rise in IL-17 levels was found only among healthy controls (p=0.02). This rise in IL-17 levels was similar between tuberculin-reactive and tuberculin-negative subjects. After PPD stimulation, patients with infiltrative TB secreted higher levels of IL-17 and IFN-γ than those affected with chronic, miliary and cavitary TB (p < 0.01). IFN-γ production from patients with infiltrative TB was even higher than for healthy controls (p < 0.01). PBMCss from tuberculin-reactive patients released higher levels of IFN-γ than tuberculin-negative subjects after PPD stimulation (p < 0.01).

CONCLUSION

Ex vivo PPD stimulation of PBMCs from patients with pulmonary TB does not significantly stimulate IL-17 release; however, higher IL-17 and IFN-γ levels are found in patients with infiltrative disease, in comparison with those affected with miliary, cavitary and chronic TB.

Thymosin β4 protects C57BL/6 mice from bleomycin-induced damage in the lung

BACKGROUND

Thymosin β4 (Tβ4) was recently found at high concentration in the bronchoalveolar lavage fluid (BALF) of scleroderma patients with lung involvement. It has been hypothesized that Tβ4 may exert a cyto-protective effect during lung injury because lower Tβ4 levels were associated with interstitial lung disease progression. Moreover, Tβ4 treatment prevented profibrotic gene expression in cardiac cells in vitro and in vivo.

MATERIALS AND METHODS

In this study, we explored a putative Tβ4 protective role in lung damage by utilizing a well-known in vivo model of lung fibrosis. C57BL/6 mice were treated with bleomycin (BLEO, 1 mg/kg) in the absence or presence of Tβ4 (6 mg/kg delivered intraperitoneally on the day of BLEO treatment and for two additional doses). After sacrifice 1 week later, measurement of fluid and collagen content in the lung, BALF analysis, myeloperoxidase (MPO) activity assay, lung histology and IHC were performed.

RESULTS

Compared with BLEO-treated mice, BLEO-treated mice who received Tβ4 did not lose as much weight and had a higher survival rate. Moreover, BLEO-induced inflammation and lung damage were substantially reduced by Tβ4 treatment, as demonstrated by the significant reduction in oedema, total collagen content, lung infiltration by leucocytes, MPO activity in lung homogenates, and histological evidence of the ongoing lung fibrosis. Results of IHC show a strong reactivity for Tβ4 in the lung tissue of Tβ4-treated mice.

CONCLUSIONS

This is the first report that shows a Tβ4 protective role in lung toxicity associated with BLEO in a mouse model. Future studies are needed to assess its putative antifibrotic properties.

A progression-free end-point for idiopathic pulmonary fibrosis trials: lessons from cancer

Idiopathic pulmonary fibrosis (IPF) is a progressive fibroproliferative disease that results in increasing morbidity. To date there is only one licensed therapy for this condition and other agents are needed for this attritional disease. Efforts to study other agents have been obstructed by an increasing division of opinion about the most clinically meaningful end-point of phase III clinical trials to demonstrate efficacy. Many clinicians believe that an agent that impedes progression of the disease is more than acceptable and will encourage the pharmaceutical industry to further develop their IPF programmes. We have been impressed by the behavioural and biological similarities of cancer and IPF, and wondered if lessons could be learned about clinical trial design from lung cancer studies. Here, we set out our arguments that the similarities with cancer justify comparing the magnitude of therapeutic effects in clinical trials in nonsmall cell lung cancer with those in successful trials in IPF. We demonstrate that efficacy is of a similar magnitude in the two chronic lung diseases. We recommend that the demonstration of similar magnitudes of progression-free disease effect in IPF, using appropriate indices, should be considered as clinically meaningful benefit in future phase III clinical trials of novel therapies.

Inhibition of PI3K prevents the proliferation and differentiation of human lung fibroblasts into myofibroblasts: the role of class I P110 isoforms

Idiopathic pulmonary fibrosis (IPF) is a progressive fibroproliferative disease characterized by an accumulation of fibroblasts and myofibroblasts in the alveolar wall. Even though the pathogenesis of this fatal disorder remains unclear, transforming growth factor-β (TGF-β)-induced differentiation and proliferation of myofibroblasts is recognized as a primary event. The molecular pathways involved in TGF-β signalling are generally Smad-dependent yet Smad-independent pathways, including phosphatidylinositol-3-kinase/protein kinase B (PI3K/Akt), have been recently proposed. In this research we established ex-vivo cultures of human lung fibroblasts and we investigated the role of the PI3K/Akt pathway in two critical stages of the fibrotic process induced by TGF-β: fibroblast proliferation and differentiation into myofibroblasts. Here we show that the pan-inhibitor of PI3Ks LY294002 is able to abrogate the TGF-β-induced increase in cell proliferation, in α- smooth muscle actin expression and in collagen production besides inhibiting Akt phosphorylation, thus demonstrating the centrality of the PI3K/Akt pathway in lung fibroblast proliferation and differentiation. Moreover, for the first time we show that PI3K p110δ and p110γ are functionally expressed in human lung fibroblasts, in addition to the ubiquitously expressed p110α and β. Finally, results obtained with both selective inhibitors and gene knocking-down experiments demonstrate a major role of p110γ and p110α in both TGF-β-induced fibroblast proliferation and differentiation. This finding suggests that specific PI3K isoforms can be pharmacological targets in IPF.

Antiproliferative effects induced by guanine-based purines require hypoxanthine-guanine phosphoribosyltransferase activity

Guanine (GUA), guanosine and GMP exert a marked growth inhibition on the U87 glioma cell line that is not seen with other tested nucleotides, nucleosides and nucleobases. This effect could be replicated in several different human tumoral cell lines. Guanine shows a higher potency than guanosine or GMP, and co-treatments with adenosine or adenine are able to antagonize or revert the antiproliferative effect of guanine. The loss of the guanine effect in a cell line bearing a mutated inactive hypoxanthine-guanine phosphoribosyltransferase (HGPRT), and the decreased potency of GUA in U87 cells silenced for HGPRT transcripts, demonstrates the central role of the intracellular metabolism of GUA for growth-inhibitory effects. Considering the potential application of growth-inhibitory substances in anticancer therapy, knowledge of the molecular mechanism underlying GUA-induced effects encourages studies aimed at defining possible tumoral targets for experimental therapies.