Regulation of high glucose-mediated mucin expression by matrix metalloproteinase-9 in human airway epithelial cells

Biomarkers in bronchiectasis

Bronchiectasis is a heterogeneous disease with multiple aetiologies and diverse clinical features. There is a general consensus that optimal treatment requires precision medicine approaches focused on specific treatable disease characteristics, known as treatable traits. Identifying subtypes of conditions with distinct underlying biology (endotypes) depends on the identification of biomarkers that are associated with disease features, prognosis or treatment response and which can be applied in clinical practice. Bronchiectasis is a disease characterised by inflammation, infection, structural lung damage and impaired mucociliary clearance. Increasingly there are available methods to measure each of these components of the disease, revealing heterogeneous inflammatory profiles, microbiota, radiology and mucus and epithelial biology in patients with bronchiectasis. Using emerging biomarkers and omics technologies to guide treatment in bronchiectasis is a promising field of research. Here we review the most recent data on biomarkers in bronchiectasis.

Metabolic syndrome facilitates histopathological changes and the risk of postoperative recurrence in chronic rhinosinusitis with nasal polyps

BACKGROUND

The relationship between metabolic syndrome (MS) and chronic rhinosinusitis with nasal polyps (CRSwNP) remains unclear. This study aimed to examine the effects of MS on histopathological features and postoperative recurrence in patients with CRSwNP.

METHODS

We recruited 529 patients with CRSwNP who underwent functional endoscopic sinus surgery. They were divided into MS and non-MS groups and followed up for 2 years to evaluate postoperative recurrence. Clinical characteristics, histopathological features, the immunoactivity of signature cytokines, and the risk of postoperative recurrence were compared between the two groups.

RESULTS

In total, 490 patients with CRSwNP were included in the study, 145 of whom experienced postoperative recurrence. The recurrence rate, tissue eosinophil count and percentage, and expression levels of IL-5 and IL-17A were significantly higher in the MS group compared to the non-MS group. Furthermore, within the MS group, patients who experienced recurrence exhibited higher tissue eosinophil counts and IL-5 and IL-17A levels than those in the non-MS group. Notably, the eosinophil count and IL-5 and IL-17A levels were higher in tissues collected during revision surgery than in those collected during primary surgery, particularly in patients with MS. Binary logistic regression analysis and Kaplan-Meier survival curves consistently indicated that MS independently increased the risk of postoperative recurrence in patients with CRSwNP. Furthermore, the risk increased with the number of MS components presented.

CONCLUSION

MS promoted tissue eosinophil infiltration, and IL-5 and IL-17A expression, and increased the risk of postoperative recurrence in patients with CRSwNP. MS was identified as an independent risk factor for postoperative recurrence, and the risk increased with an increase in the number of MS components.

High glucose exposure drives intestinal barrier dysfunction by altering its morphological, structural and functional properties

High dietary glucose consumption and hyperglycemia can result in chronic complications. Several studies suggest that high glucose (HG) induces dysfunction of the intestinal barrier. However, the precise changes remain unclear. In our study, we used in vitro models composed of Caco-2 and/or HT29-MTX cells in both monoculture and co-culture to assess the effects of long-term HG exposure on the morphological, structural, and functional properties of the intestinal barrier. Cells were grown in medium containing normal physiologic glucose (NG, 5.5 mM) or a clinically relevant HG (25 mM) concentration until 21 days. Results demonstrated that HG induced morphological changes, with the layers appearing denser and less organized than under physiological conditions, which is in accordance with the increased migration capacity of Caco-2 cells and proliferation properties of HT29-MTX cells. Although we mostly observed a small decrease in mRNA and protein expressions of three junction proteins (ZO-1, OCLN and E-cad) in both Caco-2 and HT29-MTX cells cultured in HG medium, confocal microscopy showed that HG induced a remarkable reduction in their immunofluorescence intensity, triggering disruption of their associated structural network. In addition, we highlighted that HG affected different functionalities (permeability, mucus production and alkaline phosphatase activity) of monolayers with Caco-2 and HT29-MTX cells. Interestingly, these alterations were stronger in co-culture than in monoculture, suggesting a cross-relationship between enterocytes and goblet cells. Controlling hyperglycemia remains a major therapeutical method for reducing damage to the intestinal barrier and improving therapies.

Type 2 Diabetes Mellitus and Asthma: Pathomechanisms of Their Association and Clinical Implications

Type 2 diabetes mellitus (T2DM) and asthma are chronic illnesses concomitantly present in a significant percentage of the population. Their comorbidity is associated with poor disease control and lower quality of life, thus imposing a substantial medical and economic burden worldwide. This review investigates the association between asthma and T2DM, in terms of pathogenesis, clinical outcomes, and therapeutic opportunities. Our review found an increased risk of asthma among diabetics, and vice versa. Having diabetes and poor glycemic control is associated with an increased rate of asthma exacerbations and increased mortality among those hospitalized for asthma exacerbations. The mechanisms postulated for the diabetes-asthma association include chronic low-grade inflammation, obesity, hyperinsulinemia, and possibly diabetic pneumopathy. Usage of metformin, which is the first-line drug for type 2 diabetes, was found to be associated with a decreased asthma occurrence, asthma exacerbations, and asthma-related hospitalizations. Glucagon-like peptide 1 receptor agonists were also found to be associated with a lower occurrence of asthma exacerbations. Thiazolidinediones are also associated with lower rates of asthma exacerbations, but their clinical efficacy for the same was suggested to be limited. This literature review supports a partly causative association between asthma and diabetes. This comorbidity leads to poor patient compliance, worse disease outcomes, and poor quality of life. Thus, further studies are warranted to explore the prognostic implications, therapeutic opportunities, and specific clinical practice algorithms for patients with concurrent asthma and type 2 diabetes mellitus.

Neutrophil Extracellular Traps in Asthma: Friends or Foes?

Asthma is a chronic inflammatory disease characterized by variable airflow limitation and airway hyperresponsiveness. A plethora of immune and structural cells are involved in asthma pathogenesis. The roles of neutrophils and their mediators in different asthma phenotypes are largely unknown. Neutrophil extracellular traps (NETs) are net-like structures composed of DNA scaffolds, histones and granular proteins released by activated neutrophils. NETs were originally described as a process to entrap and kill a variety of microorganisms. NET formation can be achieved through a cell-death process, termed NETosis, or in association with the release of DNA from viable neutrophils. NETs can also promote the resolution of inflammation by degrading cytokines and chemokines. NETs have been implicated in the pathogenesis of various non-infectious conditions, including autoimmunity, cancer and even allergic disorders. Putative surrogate NET biomarkers (e.g., double-strand DNA (dsDNA), myeloperoxidase-DNA (MPO-DNA), and citrullinated histone H3 (CitH3)) have been found in different sites/fluids of patients with asthma. Targeting NETs has been proposed as a therapeutic strategy in several diseases. However, different NETs and NET components may have alternate, even opposite, consequences on inflammation. Here we review recent findings emphasizing the pathogenic and therapeutic potential of NETs in asthma.

Childhood asthma and type 1 diabetes mellitus: A meta-analysis and bidirectional Mendelian randomization study

BACKGROUND

Worldwide incidence and prevalence of both asthma and type 1 diabetes mellitus (T1DM) in children have been increasing in past decades. Association between the two diseases has been found in some but not in other studies.

OBJECTIVE

We conducted a meta-analysis to verify such an association, and bidirectional Mendelian randomization analysis to examine the potential cause-effect relationships.

METHODS

Three databases (PubMed, Embase, and Web of Science) were searched from their inception to February 1, 2021. Pooled hazard ratios (HR) or odds ratios (OR), and 95% confidence intervals, were calculated. Associations between single-nucleotide polymorphisms with childhood asthma and T1DM were selected based on genome-wide association studies. The outcome datasets were obtained from FinnGen study. We used the inverse-variance-weighted (IVW), weighted median and MR-Egger methods to estimate causal effects. To assess robustness and horizontal pleiotropy, MR-Egger regression and MR pleiotropy residual sum and outlier test were conducted.

RESULTS

In meta-analysis, childhood asthma was associated with an increased risk of T1DM (HR = 1.30, 95% CI 1.05-1.61, P = .014), whereas T1DM was not associated with the risk of asthma (HR = 0.98, 95% CI 0.64-1.51, P = .941; OR = 0.84, 95% CI 0.65-1.08, P = .168). MR analysis indicated increased genetic risk of T1DM in children with asthma (OR = 1.308; 95% CI 1.030-1.661; P = .028). Analysis using the IVW method indicated no association between T1DM and genetic risk of asthma (OR = 1.027, 95%CI 0.970-1.089, P = .358).

CONCLUSION

Both meta-analysis and MR study suggested that childhood asthma was a risk factor for T1DM. No epidemiological or genetic evidence was found for an association of T1DM with asthma incidence. Further studies could be carried out to leverage this newfound insight into better clinical and experimental research in asthma and T1DM.

Diabetic Pneumopathy-A New Diabetes-Associated Complication: Mechanisms, Consequences and Treatment Considerations

Patients with diabetes are over-represented among the total cases reported with "idiopathic" pulmonary fibrosis (IPF). This raises the question, whether this is an association only or whether diabetes itself can cause pulmonary fibrosis. Recent studies in mouse models of type 1 and type 2 diabetes demonstrated that diabetes causes pulmonary fibrosis. Both types of diabetes trigger a cascade, starting with increased DNA damage, an impaired DNA repair, and leading to persistent DNA damage signaling. This response, in turn, induces senescence, a senescence-associated-secretory phenotype (SASP), marked by the release of pro-inflammatory cytokines and growth factors, finally resulting in fibrosis. Restoring DNA repair drives fibrosis into remission, thus proving causality. These data can be translated clinically to patients with type 2 diabetes, characterized by long-term diabetes and albuminuria. Hence there are several arguments, to substitute the term "idiopathic" pulmonary fibrosis (IPF) in patients with diabetes (and exclusion of other causes of lung diseases) by the term "diabetes-induced pulmonary fibrosis" (DiPF). However, future studies are required to establish this term and to study whether patients with diabetes respond to the established therapies similar to non-diabetic patients.

Diabetes and Lung Disease: A Neglected Relationship

BACKGROUND

Diabetes mellitus is a systemic disorder associated with inflammation and oxidative stress which may target many organs such as the kidney, retina, and the vascular system. The pathophysiology, mechanisms, and consequences of diabetes on these organs have been studied widely. However, no work has been done on the concept of the lung as a target organ for diabetes and its implications for lung diseases.

AIM

In this review, we aimed to investigate the effects of diabetes and hypoglycemic agent on lung diseases, including asthma, chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis, pulmonary hypertension, and lung cancer. We also reviewed the potential mechanisms by which these effects may affect lung disease patients.

RESULTS

Our results suggest that diabetes can affect the severity and clinical course of several lung diseases.

CONCLUSIONS

Although the diabetes-lung association is epidemiologically and clinically well-established, especially in asthma, the underlying mechanism and pathophysiology are not been fully understood. Several mechanisms have been suggested, mainly associated with the pro-inflammatory and proliferative properties of diabetes, but also in relation to micro- and macrovascular effects of diabetes on the pulmonary vasculature. Also, hypoglycemic drugs may influence lung diseases in different ways. For example, metformin was considered a potential therapeutic agent in lung diseases, while insulin was shown to exacerbate lung diseases; this suggests that their effects extend beyond their hypoglycemic properties.

Effect of High Glucose on MUC5B expression in Human Airway Epithelial Cells

OBJECTIVES

Excessive production of mucus results in plugging of the airway tract, which can increase morbidity and mortality in affected patients. In patients with diabetes, inflammatory airway disease appears with more frequent relapse and longer duration of symptoms. However, the effects of high glucose (HG) on the secretion of mucin in inflammatory respiratory diseases are not clear. Therefore, this study was conducted in order to investigate the effect and the brief signaling pathway of HG on MUC5B expression in human airway epithelial cells.

METHODS

The effect and signaling pathway of HG on MUC5B expression were investigated using reverse transcriptase-polymerase chain reaction (RT-PCR), real-time PCR, enzyme immunoassay, and immunoblot analysis with specific inhibitors and small interfering RNA.

RESULTS

HG increased MUC5B expression and epidermal growth factor receptor (EGFR) expression, and activated the phosphorylation of EGFR and p38 mitogen-activated protein kinase (MAPK). Pretreatment with EGFR inhibitor significantly attenuated the HG-induced phosphorylation of p38 MAPK, and pretreatments with p38 inhibitor or EGFR inhibitor significantly attenuated HG-induced MUC5B expression. In addition, knockdown of p38 MAPK by p38 MAPK siRNA significantly blocked HG-induced MUC5B expression.

CONCLUSION

These findings suggest that HG induces MUC5B expression via the sequential activations of the EGFR/p38 MAPK signaling pathway in human airway epithelial cells.