First Exploration of the Altered Microbial Gut-Lung Axis in the Pathogenesis of Human Refractory Chronic Cough.

PURPOSE: Cough represents a natural mechanism that plays an important defensive role in the respiratory tract, but in some conditions, it may become persistent, nonproductive, and harmful. In general, refractory chronic cough (RCC) occurs in about 20% of individuals; hence, we aimed to assess the presence of altered gut-lung communication in RCC patients through a compositional and functional characterization of both gut (GM) and oral microbiota (OM). METHODS: 16S rRNA sequencing was used to characterize both GM and OM composition of RCC patients and healthy controls (HC). PICRUST2 assessed functional changes in microbial communities while gas chromatography was used to evaluate fecal short-chain fatty acid levels and serum-free fatty acid (FFA) abundances. RESULTS: In comparison with HC, RCC patients reported increased saliva alpha-diversity and statistically significant beta-diversity in both GM and OM. Also, a, respectively, significant increased or reduced Firmicutes/Bacteroidota ratio in stool and saliva samples of RCC patients has been shown, in addition to a modification of the abundances of several taxa in both GM and OM. Moreover, a potential fecal over-expression of lipopolysaccharide biosynthesis and lipoic acid metabolism pathways and several differences in serum FFA levels have been reported in RCC patients than in HC. CONCLUSION: Since differences in both GM and OM of RCC patients have been documented, these findings could provide new information about RCC pathogenesis and also pave the way for the development of novel nutritional or pharmacological interventions for the management of RCC through the restoration of eubiotic gut-lung communication.

Microbiota and IPF: hidden and detected relationships.

Lung microbiota (LM) is an interesting new way to consider and redesign pathogenesis and possible therapeutic approach to many lung diseases, such as idiopathic pulmonary fibrosis (IPF), which is an interstitial pneumonia with bad prognosis. Chronic inflammation is the basis but probably not the only cause of lung fibrosis and although the risk factors are not completely clear, endogenous factors (e.g. gastroesophageal reflux) and environmental factors like cigarette smoking, industrial dusts, and precisely microbial agents could contribute to the IPF development. It is well demonstrated that many bacteria can cause epithelial cell injuries in the airways through induction of a host immune response or by activating flogosis mediators following a chronic, low-level antigenic stimulus. This persistent host response could influence fibroblast responsiveness suggesting that LM may play a role in repetitive alveolar injury in IPF. We reviewed literature regarding not only bacteria but also the role of virome and mycobiome in IPF. In fact, some viruses such as hepatitis C virus or certain fungi could be etiological agents or co-factors in the IPF progress. We aim to illustrate how the cross-talk between different local microbiotas throughout specific axis and immune modulation governed by microorganisms could be at the basis of lung dysfunctions and IPF development. Finally, since the future direction of medicine will be personalized, we suggest that the analysis of LM could be a goal to research new therapies also in IPF.

Quantitative analysis of pulmonary vasculature in systemic sclerosis at spirometry-gated chest CT.

OBJECTIVE: To prospectively investigate whether differences in pulmonary vasculature exist in systemic sclerosis (SSc) and how they are distributed in patients with different pulmonary function. METHODS: Seventy-four patients with SSc undergoing chest CT scan for interstitial lung disease (ILD) screening or follow-up were prospectively enrolled. A thorough clinical, laboratory and functional evaluation was performed the same day. Chest CT was spirometry gated at total lung capacity and images were analysed by two automated software programs to quantify emphysema, ILD patterns (ground-glass, reticular, honeycombing), and pulmonary vascular volume (PVV). Patients were divided in restricted (FVC% <80, DLco%<80), isolated DLco% reduction (iDLco- FVC%≥80, DLco%<80) and normals (FVC%≥80, DLco%≥80). Spearman ρ, Mann-Whitney tests and logistic regressions were used to assess for correlations, differences among groups and relationships between continuous variables. RESULTS: Absolute and lung volume normalised PVV (PVV/LV) correlated inversely with functional parameters and positively with all ILD patterns (ρ=0.75 with ground glass, ρ=0.68 with reticular). PVV/LV was the only predictor of DLco at multivariate analysis (p=0.007). Meanwhile, the reticular pattern prevailed in peripheral regions and lower lung thirds, PVV/LV prevailed in central regions and middle lung thirds. iDLco group had a significantly higher PVV/LV (2.2%) than normal (1.6%), but lower than restricted ones (3.8%). CONCLUSIONS: Chest CT in SSc detects a progressive increase in PVV/LV as DLco decreases. Redistribution of perfusion to less affected lung regions rather than angiogenesis nearby fibrotic lung may explain the results. Further studies to ascertain whether the increase in PVV/LV reflects a real increase in blood volume are needed.

The demographic and clinical characteristics of an Italian population of adult outpatients with chronic cough.

BACKGROUND: Chronic cough is a major health problem worldwide and patients are best managed in specialised tertiary centres. Little information is available on the characteristics of chronic cough patients in several European countries, including Italy. AIMS: We report on the demographic, anthropometric and clinical features of a large Italian population of adult chronic cough outpatients (about 1200), who were referred to a specialised clinic in Florence, Italy, from 2008 to 2018. METHODS: Demographic, environmental, lifestyle and clinical information was collected at enrolment by means of a custom-designed electronic questionnaire that only allowed for uniform responses. A subjective measure of cough-related discomfort (cough score) was also obtained using a modified Borg Scale. A multivariable logistic regression model was defined to identify the patients' characteristics associated with the cough score. RESULTS: The characteristics of the examined population (n = 1204 outpatients) were strikingly similar to those described elsewhere. Female patients outnumbered the males [n = 847 females, (70.0%)]; both females and males displayed the same average cough score. The median age of outpatients was 61 (quartile 1 = 48; quartile 3 = 70) years; age and cough duration were unrelated to the cough score. Nasal obstruction, coughing during consultation, coughing during meals, throat clearing and the presence of respiratory abnormalities were correlated with the degree of discomfort caused by coughing. DISCUSSION: The features of chronic cough patients are similar worldwide. The process of cough reflex hypersensitisation may soothe sex-related perceptual differences, leading to similar levels of discomfort. CONCLUSIONS: There seem to be clinical indicators that help in assessing the level of cough-related discomfort.

The lung microbiome: clinical and therapeutic implications.

The human respiratory tract, usually considered sterile, is currently being investigated for human-associated microbial communities. According to Dickson's conceptual model, the lung microbiota (LMt) is a dynamic ecosystem, whose composition, in healthy lungs, is likely to reflect microbial migration, reproduction, and elimination. However, which microbial genera constitutes a "healthy microbiome" per se remains hotly debated. It is now widely accepted that a bi-directional gut-lung axis connects the intestinal with the pulmonary microbiota and that the diet could have a role in modulating both microbiotas as in health as in pathological status. The LMt is altered in numerous respiratory disorders such as obstructive airway diseases, interstitial lung diseases, infections, and lung cancer. Some authors hypothesize that the use of specific bacterial strains, termed "probiotics," with positive effects on the host immunity and/or against pathogens, could have beneficial effects in the treatment of intestinal disorders and pulmonary diseases. In this manuscript, we have reviewed the literature available on the LMt to delineate and discuss the potential relationship between composition alterations of LMt and lung diseases. Finally, we have reported some meaningful clinical studies that used integrated probiotics' treatments to contrast some lung-correlated disorders.

Idiopathic Pulmonary Fibrosis: Molecular Endotypes of Fibrosis Stratifying Existing and Emerging Therapies.

Idiopathic pulmonary fibrosis (IPF) is a specific form of chronic, progressive fibrosing interstitial pneumonia of unknown causes. Current diagnostic criteria are based on radiological, clinical, and histopathological features but, unfortunately, still many patients remain undiagnosed. Two currently approved therapies, pirfenidone and nintedanib, slow down disease progression but failed to block or revert it. On the other hand, many of the therapeutic agents tested in several clinical trials have not given satisfactory answers, probably due to the pathological heterogeneity of the disease. A growing number of studies show that IPF phenotype is the common clinical outcome of a variety of different pathophysiological mechanisms that identify disease subgroups characterised by specific genetic and molecular biomarkers (endotypes). The precision medicine approach is identifying and analysing the complex system of genetic, molecular, environmental, and behavioural variables underlying the development of the disease and the response to therapy. These molecular pathways are potential targets for novel agents and useful diagnostic, prognostic, and theragnostic biomarkers. We outline the status of knowledge in this field by discussing the complex pathogenetic pathways underlying different disease subgroups and assessing a stratification approach to novel therapeutic agents based on these endotypes.

Virological and Clinical Response to Interferon-Free Regimens in Patients with HCV-Related Mixed Cryoglobulinemia: Preliminary Results of a Prospective Pilot Study.

Mixed Cryoglobulinemia (MC) is the most frequent extrahepatic manifestation of Hepatitis C virus (HCV) infection. MC is an autoimmune /B-cell lymphoproliferative disorder characterized by circulating immune-complexes, named cryoglobulins. MC patients exhibit symptoms due to a systemic vasculitis of small/medium size vessels (mixed cryoglobulinemia syndrome, MCS) in a percentage going from 5 to 30%. The first-line therapeutic option in MCS patients is the etiologic treatment and, in the past fifteen years, antiviral therapy with Pegylated-Interferon (Peg-IFN) plus Ribavirin (RBV) represented the standard of care. Lately, the arrival of direct acting antivirals (DAAs) significantly modified the cure of HCV infection, consenting the use of IFN-free regimens. Here we report a review of the literature about the role of antiviral treatment, following its evolution, in treating HCVrelated MC. Furthermore, we report the results, after 8 weeks of treatment, of a preliminary pilot prospective study, counting 17 patients with HCV-related MC with or without MCS, treated with new generation DAAs in IFN-free regimens. After 8 weeks of DAA administration, all the subjects were HCV RNA negative. Moreover, in 6/17 (35%) patients cryoglobulins disappeared and, on the whole, in all patients a decrease of the cryocrit values was observed (p<0.05). Furthermore, three MCS-HCV patients (30%) resulted to be complete clinical responders and 5 subjects (50%) partial clinical responders. Therefore, IFN-free anti-HCV treatment appears to be safe and effective in MC patients from virological and clinical points of view, thus supporting the importance of HCV eradication in leading MC remission.

Combined treatment with antiviral therapy and rituximab in patients with mixed cryoglobulinemia: review of the literature and report of a case using direct antiviral agents-based antihepatitis C virus therapy.

Mixed cryoglobulinemia (MC) is an autoimmune/B-cell lymphoproliferative disorder associated with Hepatitis C Virus (HCV) infection, manifesting as a systemic vasculitis. In the last decade, antiviral treatment (AT) with pegylated interferon (Peg-IFN) plus ribavirin (RBV) was considered the first therapeutic option for HCV-MC. In MC patients ineligible or not responsive to antivirals, the anti-CD20 monoclonal antibody rituximab (RTX) is effective. A combined AT plus RTX was also suggested. Since the introduction of direct acting antivirals (DAAs), few data were published about MC and no data about a combined schedule. Here, we report a complete remission of MC after a sustained virological response following a combined RTX/Peg-IFN+RBV+DAA (boceprevir) treatment and review the literature about the combined RTX/AT.

Long-term effect of HCV eradication in patients with mixed cryoglobulinemia: a prospective, controlled, open-label, cohort study.

UNLABELLED: Limited data are available about the efficacy of antiviral treatment in hepatitis C virus (HCV)-associated mixed cryoglobulinemia (MC), especially concerning the long-term effects of HCV eradication. The aim of this study was to evaluate the influence of MC on the virological response and the long-term effects of viral eradication on MC. We prospectively enrolled 424 HCV(+) patients belonging to the following groups: MC syndrome (MCS)-HCV (121 patients with symptomatic MC), MC-HCV (132 patients with asymptomatic MC), and HCV (158 patients without MC). Pegylated interferon plus ribavirin treatment was administered according to standard protocols. Posttreatment follow-up ranged from 35 to 124 months (mean 92.5 months). A significant difference was observed in the rate of sustained virological response between the HCV group and both the MC-HCV (P = 0.009) and MC-HCV+MCS-HCV (P = 0.014) groups. Multivariate logistic regression analysis identified cryoglobulinemia as an independent prognostic factor of nonresponse. The clinical-immunological response in MCS-HCV correlated with the virological one. All patients with sustained virological response also experienced a sustained clinical response, either complete or partial. In the majority of sustained virological response patients all MCS symptoms persistently disappeared (36 patients, 57%); in only two (3%) did definite MCS persist. All virological nonresponders were also clinical nonresponders, in spite of a transient improvement in some cases. No evolution to lymphoma was observed. For the first time we have evaluated both the effects of interferon-based therapy on HCV patients with and without MC and with and without symptoms, as well as the long-term effects of viral eradication on MC. CONCLUSION: MC is a negative prognostic factor of virological response. Clearance of HCV led to persistent resolution or improvement of MCS, strongly suggesting the need for a next generation of highly effective antiviral drugs.

Triple antiviral therapy in hepatitis C virus infection with or without mixed cryoglobulinaemia: a prospective, controlled pilot study.

BACKGROUND: Mixed cryoglobulinaemia is strongly related to hepatitis C virus infection. Treatment with peg-interferon and ribavirin has been indicated as first-line therapy for mild/moderate hepatitis C virus-related mixed cryoglobulinaemia. AIM: To evaluate the safety and efficacy of triple boceprevir-based antiviral therapy in patients with or without mixed cryoglobulinaemia previously treated with peg-interferon and ribavirin, and with advanced liver disease. METHODS: Thirty-five hepatitis C virus-positive patients (17 with asymptomatic mixed cryoglobulinaemia, 5 with symptomatic mixed cryoglobulinaemia, and 11 without mixed cryoglobulinaemia) were treated with triple boceprevir-based antiviral therapy. RESULTS: In 19/22 cryoglobulinaemic subjects (86%), the addition of boceprevir induced cryocrit disappearance. Cryocrit behaviour was related to virological response, with improvement of symptoms upon undetectable viraemia and reappearance after virological breakthrough. The rate of sustained virological response was lower in cryoglobulinaemic patients than in patients without mixed cryoglobulinaemia (23.8% vs 70% respectively, p=0.01). CONCLUSION: Boceprevir-based therapy was safe and effective in cryoglobulinaemic patients. The correlation between direct inhibition of hepatitis C virus replication and clinical improvement in mixed cryoglobulinaemic patients is definitive proof of the key pathogenetic role played by viral replication. Further studies are needed to confirm and clarify the reduced virological response in patients with mixed cryoglobulinaemia.