Effect and safety of mycophenolate mofetil in idiopathic pulmonary fibrosis. Pulm Med. 2011;2011:849035. [PMID: 22135741 PMCID: PMC3206363 DOI: 10.1155/2011/849035]

The Plastic Interplay between Lung Regeneration Phenomena and Fibrotic Evolution: Current Challenges and Novel Therapeutic Perspectives

Interstitial lung diseases (ILDs) are a heterogeneous group of pulmonary disorders characterized by variable degrees of inflammation, interstitial thickening, and fibrosis leading to distortion of the pulmonary architecture and gas exchange impairment. Among them, idiopathic pulmonary fibrosis (IPF) displays the worst prognosis. The only therapeutic options consist of the two antifibrotic drugs, pirfenidone and nintedanib, which limit fibrosis progression but do not reverse the lung damage. The shift of the pathogenetic paradigm from inflammatory disease to epithelium-derived disease has definitively established the primary role of type II alveolar cells, which lose their epithelial phenotype and acquire a mesenchymal phenotype with production of collagen and extracellular matrix (EMC) deposition. Some predisposing environmental and genetic factors (e.g., smoke, pollution, gastroesophageal reflux, variants of telomere and surfactant genes) leading to accelerated senescence set a pro-fibrogentic microenvironment and contribute to the loss of regenerative properties of type II epithelial cells in response to pathogenic noxae. This review provides a complete overview of the different pathogenetic mechanisms leading to the development of IPF. Then, we summarize the currently approved therapies and the main clinical trials ongoing. Finally, we explore the potentialities offered by agents not only interfering with the processes of fibrosis but also restoring the physiological properties of alveolar regeneration, with a particular focus on potentialities and concerns about cell therapies based on mesenchymal stem cells (MSCs), whose anti-inflammatory and immunomodulant properties have been exploited in other fibrotic diseases, such as graft versus host disease (GVHD) and COVID-19-related ARDS.

Idiopathic pulmonary fibrosis: Current and future treatment

Objectives

Idiopathic pulmonary fibrosis (IPF) is a chronic fibrotic lung disease characterized by dry cough, fatigue, and progressive exertional dyspnea. Lung parenchyma and architecture is destroyed, compliance is lost, and gas exchange is compromised in this debilitating condition that leads inexorably to respiratory failure and death within 3–5 years of diagnosis. This review discusses treatment approaches to IPF in current use and those that appear promising for future development.

Data Source

The data were obtained from the Randomized Controlled Trials and scientific studies published in English literature. We used search terms related to IPF, antifibrotic treatment, lung transplant, and management.

Results

Etiopathogenesis of IPF is not fully understood, and treatment options are limited. Pathological features of IPF include extracellular matrix remodeling, fibroblast activation and proliferation, immune dysregulation, cell senescence, and presence of aberrant basaloid cells. The mainstay therapies are the oral antifibrotic drugs pirfenidone and nintedanib, which can improve quality of life, attenuate symptoms, and slow disease progression. Unilateral or bilateral lung transplantation is the only treatment for IPF shown to increase life expectancy.

Conclusion

Clearly, there is an unmet need for accelerated research into IPF mechanisms so that progress can be made in therapeutics toward the goals of increasing life expectancy, alleviating symptoms, and improving well‐being.

Safety and Effectiveness of Mycophenolate Mofetil in Interstitial Lung Diseases: Insights from a Machine Learning Radiographic Model

INTRODUCTION

Treatment of interstitial lung diseases (ILDs) other than idiopathic pulmonary fibrosis (IPF) often includes systemic corticosteroids. Use of steroid-sparing agents is amenable to avoid potential side effects.

METHODS

Functional indices and high-resolution computed tomography (HRCT) patterns of patients with non-IPF ILDs receiving mycophenolate mofetil (MMF) with a minimum follow-up of 1 year were analyzed. Two independent radiologists and a machine learning software system (Imbio 1.4.2.) evaluated HRCT patterns.

RESULTS

Fifty-five (n = 55) patients were included in the analysis (male: 30 [55%], median age: 65.0 [95% CI: 59.7-70.0], mean forced vital capacity %predicted [FVC %pred.] ± standard deviation [SD]: 69.4 ± 18.3, mean diffusing capacity of lung for carbon monoxide %pred. ± SD: 40.8 ± 14.3, hypersensitivity pneumonitis: 26, connective tissue disease-ILDs [CTD-ILDs]: 22, other ILDs: 7). There was no significant difference in mean FVC %pred. post-6 months (1.59 ± 2.04) and 1 year (-0.39 ± 2.49) of treatment compared to baseline. Radiographic evaluation showed no significant difference between baseline and post-1 year %ground glass opacities (20.0 [95% CI: 14.4-30.0] vs. 20.0 [95% CI: 14.4-25.6]) and %reticulation (5.0 [95% CI: 2.0-15.6] vs. 7.5 [95% CI: 2.0-17.5]). A similar performance between expert radiologists and Imbio software analysis was observed in assessing ground glass opacities (intraclass correlation coefficient [ICC] = 0.73) and reticulation (ICC = 0.88). Fourteen patients (25.5%) reported at least one side effect and 8 patients (14.5%) switched to antifibrotics due to disease progression.

CONCLUSION

Our data suggest that MMF is a safe and effective steroid-sparing agent leading to disease stabilization in a proportion of patients with non-IPF ILDs. Machine learning software systems may exhibit similar performance to specialist radiologists and represent fruitful diagnostic and prognostic tools.

Rethinking Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a devastating disease for patients and their loved ones. Since initial efforts to characterize this disease in the 1960s, understanding of IPF has evolved considerably. Such evolution has continually challenged prior diagnostic and treatment paradigms, ushering in an era of higher confidence diagnoses with less invasive procedures and more effective treatments. This review details how research and clinical experience over the past half century have led to a rethinking of IPF. Here, the evolution in understanding of IPF pathogenesis, diagnostic evaluation and treatment approach is discussed.

Cell Therapy for Idiopathic Pulmonary Fibrosis: Rationale and Progress to Date

Idiopathic pulmonary fibrosis (IPF) is a devastating disease characterized by progressive lung scarring due to unknown injurious stimuli ultimately leading to respiratory failure. Diagnosis is complex and requires a combination of clinical, laboratory, radiological, and histological investigations, along with exclusion of known causes of lung fibrosis. The current understanding of the disease etiology suggests an interaction between genetic factors and epigenetic alterations in susceptible, older individuals. Prognosis is dismal and current treatment options include anti-fibrotic agents that only slow down disease progression and carry considerable side effects that hamper patients' quality of life. Therefore, the need for new, more effective treatments, alone or in combination with existing pharmacotherapy, is sorely needed. Regenerative medicine, the potential use of cell therapies to treat destructive diseases that cause architectural distortion to the target organ, has also emerged as an alternative therapeutic for lung diseases with unfavorable prognosis such as IPF. Mesenchymal stem cells (MSCs) and type II alveolar epithelial cells (AEC2s) have been used and their safety has been demonstrated. In the case of MSCs, both homogenic and allogeneic sources have been used and both are considered viable options without immunosuppressive therapy, taking into consideration the absence of immunogenicity and HLA response. AEC2s have been used in one trial with promising results but their use requires a deceased donor and immunosuppressive pre-treatment. In this review, we briefly summarize the current state of knowledge regarding the pathogenesis of IPF, and the background and rationale for using MSCs or AEC2s as potential treatment options. We list and describe the clinical trials completed to date and provide a comparison of their methods and results as well as a possible way forward.

Disparate Interferon Signaling and Shared Aberrant Basaloid Cells in Single-Cell Profiling of Idiopathic Pulmonary Fibrosis and Systemic Sclerosis-Associated Interstitial Lung Disease

Idiopathic pulmonary fibrosis (IPF) and systemic sclerosis-associated interstitial lung disease (SSc-ILD) differ in the predominant demographics and identified genetic risk alleles of effected patients, however both diseases frequently progress to respiratory failure and death. Contrasting advanced SSc-ILD to IPF provides insight to the role dysregulated immunity may play in pulmonary fibrosis. To analyze cell-type specific transcriptome commonalities and differences between IPF and SSc-ILD, we compared single-cell RNA-sequencing (scRNA-seq) of 21 explanted lung tissue specimens from patients with advanced IPF, SSc-ILD, and organ donor controls. Comparison of IPF and SSc-ILD tissue identified divergent patterns of interferon signaling, with interferon-gamma signaling upregulated in the SPP1hi and FABP4hi macrophages, cytotoxic T cells, and natural kill cells of IPF, while type I interferon signaling and production was upregulated in the corresponding SSc-ILD populations. Plasmacytoid dendritic cells were found in diseased lungs only, and exhibited upregulated cellular stress pathways in SSc-ILD compared to IPF. Alveolar type I cells were dramatically decreased in both IPF and SSc-ILD, with a distinct transcriptome signature separating these cells by disease. KRT5-/KRT17+ aberrant basaloid cells exhibiting markers of cellular senescence and epithelial-mesenchymal transition were identified in SSc-ILD for the first time. In summary, our study utilizes the enriched capabilities of scRNA-seq to identify key divergent cell types and pathways between IPF and SSc-ILD, providing new insights into the shared and distinct mechanisms between idiopathic and autoimmune interstitial lung diseases.

Anti-fibrotic effect of mycophenolate mofetil on Peyronie's disease experimentally induced with TGF-β

The aim of the present study was to evaluate the histological, histochemical, and stereological changes caused by mycophenolate mofetil (MMF) on the tunica albuginea of rat penises submitted to an injection of transforming growth factor beta (TGF-β) for the induction of Peyronie's disease (PD). Twenty adult male Wistar rats were divided into four groups: Control group; TGF-β group (TGF-β injection); MMF-7d group (treated with MMF 7 days after induction with TGF-β); and MMF-30d group (treated with MMF 30 days after induction with TGF-β). The steorological evaluation included the relative volume of different types of connective fibres of the tunica albuginea. The histochemical analysis revealed the fragmentation and degradation of elastin in the tunica albuginea. This process was partially reversed in the MMF-7d group and a situation very close to normality was observed in the MMF-30d group. In the collagen III/collagen I ratio it was observed increase in this ratio in the TGF-β (59.4 ± 5.53) and MMF-7d (49 ± 18.2) groups and a decrease in the MMF-30d group (28.7 ± 4), approaching normality. The injection of TGF-β promoted fibrotic alterations in the penile tunica albuginea in Wistar rats corresponding to PD. In this model, MMF acts as a regenerating anti-fibrotic agent.

Effectiveness and safety of mycophenolate mofetil in idiopathic pulmonary fibrosis

BACKGROUND

Currently available antifibrotic treatments may slow down disease progression in idiopathic pulmonary fibrosis (IPF), but are associated with potentially significant side effects and are costly. Mycophenolate mofetil (MMF) is well known for its potent immunosuppressive properties and possesses important antiproliferative and antifibrotic effects. The safety and effectiveness of MMF in IPF is unknown.

METHODS

We performed a retrospective multicohort analysis of IPF patients treated with MMF compared to those treated with either ineffective/harmful treatments or no treatment. Longitudinal change in forced vital capacity (FVC) between the groups was analyzed using a mixed model with random intercept and slope allowing for repeated measures within subjects. Categorical change in FVC, median overall survival, and adverse events were also assessed.

RESULTS

Forty-one IPF patients were included: 11 treated with MMF, 20 treated with ineffective/harmful agents (such as prednisone, azathioprine, and/or NAC), and 10 did not receive any specific treatment for their IPF. After one year, there was a trend towards reduced FVC decline in the MMF-treated group (-76.3 mL, -2.4% of predicted) compared to the non-MMF-treated (-165 mL, -8.9% of predicted) and the no-treatment (-239 mL, -11.5% of predicted) groups, respectively. By categorical change, there was a trend towards greater FVC stability in the MMF-treated group (87.5%) compared to the non-MMF-treated (57%) and the no-treatment groups (50%), respectively. MMF-treated IPF patients had a trend towards improved median overall survival (40.3 months) compared to the non-MMF-treated (25.5 months) and the no-treatment (29.3 months) groups, respectively. Treatment-related adverse events were not different between groups; however, very few adverse events were reported overall.

CONCLUSIONS

MMF treatment was associated with potentially clinically important trends toward reduced annual FVC decline (similar to approved antifibrotics), greater FVC stability and improved overall survival in IPF patients. MMF was generally safe, well tolerated, and relatively inexpensive. Future prospective studies of MMF in combination with antifibrotic therapy in IPF are needed.

Promising new treatment targets in patients with fibrosing lung disorders

The processes of lung fibrogenesis and fibrotic healing are common to a number of conditions with different etiologies. The lungs are the only affected organ in some cases, whereas in others, several organ systems are involved. Therapeutic options can be discussed from various perspectives. In this review, we address the localization of therapeutic targets with regard to cell compartments, including secreted ligands, cell surface, plasma membrane-cytosol interplay, cytosol and nucleus. Complex approach using stem cell therapy is also discussed. As the prognosis of patients with these disorders remains grim, treatment combinations targeting different molecules within the cell should sometimes be considered. It is reasonable to assume that blocking specific pathways will more likely lead to disease stabilization, while stem cell-based treatments could potentially restore lung architecture. Gene therapy could be a candidate for preventive care in families with proven specific gene polymorphisms and documented familial lung fibrosis. Chronobiology, that takes into account effect of circadian rhythm on cell biology, has demonstrated that timed drug administration can improve treatment outcomes. However, the specific recommendations for optimal approaches are still under debate. A multifaceted approach to interstitial lung disorders, including cooperation between those doing basic research and clinical doctors as well as tailoring research and treatment strategies toward (until now) unmet medical needs, could improve our understanding of the diseases and, above all, provide benefits for our patients.