Identification of neutrophil activation markers as novel surrogate markers of CF lung disease

Increased Plasma YKL-40 Level and Chitotriosidase Activity in Cystic Fibrosis Patients

We investigated plasma YKL-40 levels and chitotriosidase (CHIT1) activity in patients with cystic fibrosis (CF) lung disease and evaluated clinically relevant factors that may affect their levels. Plasma samples were obtained from pediatric (n = 19) and adult patients (n = 15) during exacerbation, discharge, and stable period of the disease. YKL-40 levels and chitotriosidase activity were measured by enzyme-linked immunosorbent assay and fluorometric assay, respectively. Data were compared with healthy children and adults of similar age. YKL-40 levels of pediatric and adult CF patients at all periods were significantly higher than controls (p < 0.001 and p < 0.05). CHIT1 activities of adult patients at all periods were significantly higher compared to controls (p < 0.05). On the other hand, CHIT1 activities of pediatric CF patients were similar with controls. YKL-40 levels of exacerbation period of adult CF patients were negatively correlated with forced vital capacity (FVC) (r =  - 0.800, p = 0.014) and forced expiratory volume in 1 s (FEV1) (r =  - 0.735, p = 0.008). YKL-40 levels in the exacerbation period of pediatric CF patients were negatively correlated with FVC (r =  - 0.697, p = 0.0082) and FEV1 (r =  - 0.720, p = 0.006). CHIT1 activity may be a valuable marker of chronic inflammation in adult CF patients who suffer from CF for a longer period compared to pediatric patients. Increased YKL-40 levels in both pediatric and adult patients compared to controls may point to a role in between CF pathology.

Peripheral blood mononuclear cell response to YKL-40 and Galectin-3 in cystic fibrosis

BACKGROUND

Elevated circulating levels of YKL-40 correlate with disease severity in Cystic Fibrosis (CF), but the role of YKL-40 in the inflammatory response in CF is still under investigation. Our main goal was to evaluate if YKL-40 can modulate the expression of major cytokines (IL-6, IL-10, IL-13) implicated in the inflammatory response in CF. A secondary goal was to explore the interactions between YKL-40 and other circulating proteins to determine the impacts on cytokine modulation.

METHOD

Peripheral blood mononuclear cells (PBMCs) were isolated from the blood of 83 adult CF patients in stable clinical condition. PBMCs were treated with human YKL-40 followed by the measure of IL-6, IL-10 and IL-13 gene expression. Protein arrays were used to explore the interactions between YKL-40 and circulating proteins. Interaction with Galectin-3 (GAL3) was identified, and confirmed by binding assay. Cytokine gene expressions were again monitored by RT-qPCR after PBMC treatment with GAL3, with or without YKL-40 co-stimulation.

RESULTS

Following YKL-40 stimulation, PBMC gene expression of IL-6, IL-10 and IL-13 varies across patients. IL-6 and IL-13 are coexpressed, but this response was different in male and female patients. GAL3 protein was detected in the blood of CF patients, and a molecular interaction with YKL-40 was identified. GAL3 did not interfere with the YKL-40 stimulation of IL-6, IL-10 and IL-13 but may modulate the coexpression.

CONCLUSION

We observed that YKL-40 stimulation had a variable impact on IL-6, IL-10, and IL-13 gene expression in CF PBMCs and uncovered an interaction between GAL3 and YKL-40 in the serum of CF patients. Our findings suggest that YKL-40 is not only a biomarker of disease severity in CF, but it might play an active role in the inflammatory pathophysiology of the disease.

Laboratory biomarkers for lung disease severity and progression in cystic fibrosis

Although the clinical outcomes of cystic fibrosis (CF) have been markedly improved through the recent implementation of novel CF transmembrane conductance regulator (CFTR) modulator drugs, robust and reliable biomarkers are still demanded for the early detection of CF lung disease progression, monitoring treatment efficacy and predicting life-threatening clinical complications. Thus, there is an unmet need to identify and validate novel, ideally blood based biomarkers with strong correlations to the severity of CF lung disease, which represents a major contribution to overall CF morbidity and mortality. In this review, we aim to summarize the utility of thus far studied blood-, sputum- and bronchoalveolar lavage (BAL)-based biomarkers to evaluate inflammatory conditions in the lung and to follow treatment efficacy in CF. Measurements of sweat chloride concentrations and the spirometric parameter FEV₁ are currently utilized to monitor CFTR function and the effect of various CF therapies. Nonetheless, both have inherent pitfalls and limitations, thus routinely analyzed biomarkers in blood, sputum or BAL samples are required as surrogates for lung disorders. Recent discovery of new protein (e.g. HE4) and RNA-based biomarkers, such as microRNAs may offer a higher efficacy, which in aggregate may be valuable to evaluate disease prognosis and to substantiate CF drug efficacy.

Matrix metalloproteinases and liver fibrosis (translational aspects)

Liver fibrosis, a reversible wound-healing response to chronic cellular injury, reflects a balance between liver repair and progressive substitution of the liver parenchyma by scar tissue. Complex mechanisms that underlie liver fibrogenesis are summarized to provide the basis for generating targeted therapies to reverse fibrogenesis and improve the outcomes of patients with chronic liver disease. This minireview presents some pathophysiological aspects of liver fibrosis as a dynamic process and elucidates matrix metalloproteinases (MMPs) and their role within as well as beyond matrix degradation. Open questions remain, whether inhibition of fibrogenesis or induction of fibrolysis is the key mechanism to resolve fibrosis. And a point of principle might be whether regeneration of liver cirrhosis is possible. Will we ever cure fibrosis?

Assessment of pathologic increase in liver stiffness enables earlier diagnosis of CFLD: Results from a prospective longitudinal cohort study

About 30% of patients with Cystic Fibrosis (CF) develop CF-associated liver disease (CFLD). Recent studies have shown that transient elastography (TE), as a method to quantify liver stiffness, allows non-invasive diagnosis of CFLD in adults and children with CF. Within this study we aimed to prospectively identify patients at risk for development of CFLD by longitudinal analysis of liver stiffness and fibrosis scores in a 5-year follow-up. 36 pediatric and 16 adult patients with initial liver stiffness below the cut-off value indicative of CFLD (6.3 kPa) were examined by transient elastography for 4-5 years. TE, APRI-, and FIB-4-scores were assessed and compared by Kruskal-Wallis test and receiver operating characteristic (ROC)-analysis. Frequencies were compared by Chi2-test. Among the 36 patients participating in this study, a subgroup of 9 patients developed liver stiffness >6.3 kPa after 4-5 years with an increase of ΔTE >0.38 kPa/a (the group with increasing liver stiffness was labelled TEinc). APRI- and FIB-4 scores confirmed the rationale for grouping. The frequency of CFLD assessed by conventional diagnosis was significantly higher in TEinc-group compared to the control group (TEnorm). None of the adult CF patients matched criteria for TEinc-group. For the first time it was shown that the non-invasive longitudinal assessment of TE allows identification of patients with progression of CFLD in a subgroup of juvenile but not in adult CF patients. Comparing TE to conventional fibrosis-scores underlined the strength of the continuous assessment of liver stiffness for the exact diagnosis of progressive CFLD. The newly described cut-off for pathologic increase of liver stiffness, ΔTEcutoff = 0.38kPa/a, might enable to detect developing CFLD using consequent follow up TE measurements before reaching the level of stiffness indicating established CFLD. Nevertheless, the limited size of the analyzed cohort should encourage a prospective, multi-center, long term follow up study to confirm the suggested cut-off for the rise in liver stiffness.

Glycoprotein YKL-40 Levels in Plasma Are Associated with Fibrotic Changes on HRCT in Asbestos-Exposed Subjects

YKL-40 is a chitinase-like glycoprotein produced by alternatively activated macrophages that are associated with wound healing and fibrosis. Asbestosis is a chronic asbestos-induced lung disease, in which injury of epithelial cells and activation of alveolar macrophages lead to enhanced collagen production and fibrosis. We studied if YKL-40 is related to inflammation, fibrosis, and/or lung function in subjects exposed to asbestosis. Venous blood samples were collected from 85 men with moderate or heavy occupational asbestos exposure and from 28 healthy, age-matched controls. Levels of plasma YKL-40, CRP, IL-6, adipsin, and MMP-9 were measured with enzyme-linked immunosorbent assay (ELISA). Plasma YKL-40 levels were significantly higher in subjects with asbestosis (n = 19) than in those with no fibrotic findings in HRCT following asbestos exposure (n = 66) or in unexposed healthy controls. In asbestos-exposed subjects, plasma YKL-40 correlated negatively with lung function capacity parameters FVC (Pearson's r −0.259, p = 0.018) and FEV₁ (Pearson's r −0.240, p = 0.028) and positively with CRP (Spearman's rho 0.371, p < 0.001), IL-6 (Spearman's rho 0.314, p = 0.003), adipsin (Spearman's rho 0.459, p < 0.001), and MMP-9 (Spearman's rho 0.243, p = 0.025). The present finding suggests YKL-40 as a biomarker associated with fibrosis and inflammation in asbestos-exposed subjects.

Biomarker Profiles in Women with PCOS and PCOS Offspring; A Pilot Study

Objective

To study metabolic/inflammatory biomarker risk profiles in women with PCOS and PCOS offspring.

Design

Cross-sectional comparison of serum biomarkers.

Setting

University Medical Center Utrecht.

Patients

Hyperandrogenic PCOS women (HA-PCOS, n = 34), normoandrogenic PCOS women (NA-PCOS, n = 34), non-PCOS reference population (n = 32), PCOS offspring (n = 14, age 6–8 years), and a paedriatic reference population (n = 30).

Main Outcome Measure(s)

Clustering profile of adipocytokines (IL-1b, IL-6, IL-13, IL-17, IL-18, TNF-α, adiponectin, adipsin, leptin, chemerin, resistin, RBP4, DPP-IV/sCD26, CCL2/MCP-1), growth factors (PIGF, VEGF, sVEGF-R1), soluble cell adhesion molecules (sICAM-1/sCD54, sVCAM-1/sCD106), and other inflammatory related proteases (MMP-9, S100A8, Cathepsin S). Differences in median biomarker concentrations between groups, and associations with the free androgen index (FAI; Testosterone/SHBG x100).

Results

The cluster analysis identified leptin, RBP-4, DPP-IV and adiponectin as potential discriminative markers for HA-PCOS with a specifically strong correlation in cases with increased BMI. Leptin (R² = 0.219) and adiponectin (R² = 0.182) showed the strongest correlation with the FAI. When comparing median protein concentrations adult PCOS women with or without hyperandrogenemia, the most profound differences were observed for leptin (P < 0.001), DPP-IV (P = 0.005), and adiponectin (P < 0.001). Adjusting for age, BMI and multiple testing attenuated all differences. In PCOS offspring, MMP-9 (P = 0.001) and S100A8 (P < 0.001) concentrations were significantly higher compared to a healthy matched reference population, even after correcting for age and BMI and adjustment for multiple testing.

Conclusion

In this preliminary investigation we observed significant differences in adipocytokines between women with or without hyperandrogenic PCOS and non-PCOS controls, mostly influenced by BMI. Leptin and adiponectin showed the strongest correlation with the FAI in adult women with PCOS. In PCOS offspring other inflammatory biomarkers (MMP-9, S100A8) were increased, suggesting that these children may exhibit increased chronic low-grade inflammation. Additional research is required to confirm results of the current exploratory investigation.

Pathological Hyaluronan Matrices in Cystic Fibrosis Airways and Secretions

Hyaluronan (HA) has been used in treatment of cystic fibrosis (CF) via a nebulizer and has demonstrated success in clinical outcomes. HA is an important glycosaminoglycan that is cross-linked by heavy chains (HCs) from inter-α-inhibitor during inflammation. HC cross-linked HA (HC-HA) becomes significantly more adhesive for leukocytes than non-cross-linked HA, which can enhance inflammation. Our studies tested the hypothesis that HC-HA is present in CF airways and that altered ratios of HC-HA to its degradation into relatively lower molecular weight HA contribute to the pathophysiology of chronic inflammation in CF. We evaluated the distribution, levels, and size of HC-HA within CF, healthy, and diseased control lung, bronchus, and sputum tissues by histological and biochemical approaches. HC-HA was significantly elevated in CF, with deposits around the pulmonary vasculature, airway submucosa, and in the stroma of the submucosal glands. The increased infiltration of leukocyte populations correlated with the distribution of HC-HA matrices in the airways. Elevated lung tissue HC-HA correlated with decreased HA levels in CF mucus and sputum compared with controls, suggesting that aberrant degradation and cross-linking of HA in lung tissue is a unique feature of CF. The accumulation and degradation of proinflammatory HC-HA in CF lung tissue suggests that aberrant HA catabolism and cross-linking may contribute to chronic inflammation in airway tissues and affect mucus viscosity in CF airways.