Prognostic value of serum growth differentiation factor-15 in patients with chronic obstructive pulmonary disease exacerbation

GDF15 as a key disease target and biomarker: linking chronic lung diseases and ageing

Growth differentiation factor 15 (GDF15), a member of the transforming growth factor-beta superfamily, is expressed in several human organs. In particular, it is highly expressed in the placenta, prostate, and liver. The expression of GDF15 increases under cellular stress and pathological conditions. Although numerous transcription factors directly up-regulate the expression of GDF15, the receptors and downstream mediators of GDF15 signal transduction in most tissues have not yet been determined. Glial cell-derived neurotrophic factor family receptor α-like protein was recently identified as a specific receptor that plays a mediating role in anorexia. However, the specific receptors of GDF15 in other tissues and organs remain unclear. As a marker of cell stress, GDF15 appears to exert different effects under different pathological conditions. Cell senescence may be an important pathogenetic process and could be used to assess the progression of various lung diseases, including COVID-19. As a key member of the senescence-associated secretory phenotype protein repertoire, GDF15 seems to be associated with mitochondrial dysfunction, although the specific molecular mechanism linking GDF15 expression with ageing remains to be elucidated. Here, we focus on research progress linking GDF15 expression with the pathogenesis of various chronic lung diseases, including neonatal bronchopulmonary dysplasia, idiopathic pulmonary fibrosis, chronic obstructive pulmonary disease, and pulmonary hypertension, suggesting that GDF15 may be a key biomarker for diagnosis and prognosis. Thus, in this review, we aimed to provide new insights into the molecular biological mechanism and emerging clinical data associated with GDF15 in lung-related diseases, while highlighting promising research and clinical prospects.

Predictive Value of GDF-15 and sST2 for Pulmonary Hypertension in Acute Exacerbation of Chronic Obstructive Pulmonary Disease

Objective

To confirm whether growth differentiation factor-15 (GDF-15) and soluble suppression of tumorigenicity 2 (sST2) are indicators of pulmonary hypertension in acute exacerbation of chronic obstructive pulmonary disease (AECOPD-PH).

Methods

All patients admitted to the hospital with AECOPD between July 2020 and October 2021 were enrolled. The patients were then categorized into AECOPD and AECOPD-PH groups according to PH probability, and the differences in GDF-15 and sST2 serum levels in the AECOPD and AECOPD-PH groups were compared. Correlation analysis was carried out to explore the association between GDF-15 and sST2 serum levels and the length of hospital stay of patients with AECOPD-PH. Receiver operating characteristic curve analysis was used to assess the clinical significance of GDF-15 and sST2 in predicting patients with AECOPD-PH.

Results

Included in this study were 126 patients with AECOPD, including 69 with AECOPD and 57 with AECOPD-PH. The serum levels of GDF-15 and sST2 in the AECOPD-PH group were significantly higher than those in the AECOPD group (P < 0.05). There was no significant correlation between the length of hospital stay in AECOPD-PH patients and GDF-15 and sST2 serum levels (P > 0.05). The area under the curves of GDF-15, sST2, and GDF-15 + sST2 for predicting AECOPD-PH and AECOPD-PH patients with poor prognosis were >0.60 and 0.70, respectively. The optimal cutoff values of GDF-15 and sST2 for predicting AECOPD-PH were 1125.33 pg/mL and 80.68 ng/mL and 1309.72 pg/mL and 59.10 ng/mL for predicting AECOPD-PH patients with poor prognosis, respectively.

Conclusion

GDF-15 and sST2 levels may be useful in the prediction of AECOPD-PH.

Alterations in circulating mitochondrial signals at hospital admission for COPD exacerbation

BACKGROUND

Chronic obstructive pulmonary disease (COPD) exacerbation (ECOPD) alters the natural course of the disease. To date, only C-reactive protein has been used as a biomarker in ECOPD, but it has important limitations. The mitochondria release peptides (Humanin (HN), FGF-21, GDF-15, MOTS-c and Romo1) under certain metabolic conditions. Here, we aimed to evaluate the pathophysiologic, diagnostic and prognostic value of measuring serum mitochondrial peptides at hospital admission in patients with ECOPD.

METHODS

A total of 51 consecutive patients admitted to our hospital for ECOPD were included and followed for 1 year; in addition, 160 participants with stable COPD from our out-patient clinic were recruited as controls.

RESULTS

Serum FGF-21 (p < .001), MOTS-c (p < .001) and Romo1 (p = .002) levels were lower, and GDF-15 (p < .001) levels were higher, in patients with ECOPD than stable COPD, but no differences were found in HN. In receiver operating characteristic analysis, MOTS-c (AUC 0.744, 95% CI 0.679-0.802, p < .001) and GDF-15 (AUC 0.735, 95% CI 0.670-0.793, p < .001) had the best diagnostic power for ECOPD, with a diagnostic accuracy similar to that of C-RP (AUC 0.796 95% IC 0.735-0.848, p < .001). FGF-21 (AUC 0.700, 95% CI 0.633-0.761, p < .001) and Romo1 (AUC 0.645 95% CI 0.573-0.712, p = .001) had lower diagnostic accuracy. HN levels did not differentiate patients with ECOPD versus stable COPD (p = .557). In Cox regression analysis, HN (HR 2.661, CI95% 1.009-7.016, p = .048) and MOTS-c (HR 3.441, CI95% 1.252-9.297, p = .016) levels exceeding mean levels were independent risk factors for re-admission.

CONCLUSIONS

Most mitochondrial peptides are altered in ECOPD, as compared with stable COPD. MOTS-c and GDF15 levels have a diagnostic accuracy similar to C-RP for ECOPD. HN and MOTS-c independently predict future re-hospitalization.

Characterization of atherosclerotic plaques in blood vessels with low oxygenated blood and blood pressure (Pulmonary trunk): role of growth differentiation factor-15 (GDF-15)

BACKGROUND

Growth differentiation factor (GDF)-15 is linked to inflammation, cancer, and atherosclerosis. GDF-15 is expressed in most tissues but is extremely induced under pathological conditions. Elevated serum levels are suggested as a risk factor and a marker for cardiovascular diseases. However, the cellular sources and the effects of GDF-15 on the cardiovascular system have not been completely elucidated including progression, and morphology of atherosclerotic plaques. Thus, this work aimed to characterize the influence of GDF-15 deficiency on the morphology of atherosclerotic plaques in blood vessels with low-oxygen blood and low blood pressure as the pulmonary trunk (PT), in hypercholesterolemic ApoE-/- mice.

METHODS

GDF-15-/- ApoE-/- mice were generated by crossbreeding of ApoE-/-- and GDF-15-/- mice. After feeding a cholesterol-enriched diet (CED) for 20 weeks, samples of the brachiocephalic trunk (BT) and PT were dissected and lumen stenosis (LS) was measured. Furthermore, changes in the cellularity of the PT, amounts of apoptosis-, autophagy-, inflammation- and proliferation-relevant proteins were immunohisto-morphometrically analyzed. Additionally, we examined an atherosclerotic plaque in a human post mortem sample of the pulmonary artery.

RESULTS

After CED the body weight of GDF-15-/-ApoE-/- was 22.9% higher than ApoE-/-. Double knockout mice showed also an 35.3% increase of plasma triglyceride levels, whereas plasma cholesterol was similar in both genotypes. LS in the BT and PT of GDF-15-/-ApoE-/- mice was significantly reduced by 19.0% and by 6.7% compared to ApoE-/-. Comparing LS in PT and BT of the same genotype revealed a significant 38.8% (ApoE-/-) or 26.4% (GDF-15-/-ApoE-/-) lower LS in the PT. Immunohistomorphometry of atherosclerotic lesions in PT of GDF-15-/-ApoE-/- revealed significantly increased levels (39.8% and 7.3%) of CD68 + macrophages (MΦ) and α-actin + smooth muscle cells than in ApoE-/-. The density of TUNEL + , apoptotic cells was significantly (32.9%) higher in plaques of PT of GDF-15-/-ApoE-/- than in ApoE-/-. Analysis of atherosclerotic lesion of a human pulmonary artery showed sm-α-actin, CD68+, TUNEL+, Ki67+, and APG5L/ATG+ cells as observed in PT. COX-2+ and IL-6+ immunoreactivities were predominantly located in endothelial cells and subendothelial space. In BT and PT of GDF15-/-ApoE-/- mice the necrotic area was 10% and 6.5% lower than in ApoE-/-. In BT and PT of GDF15-/-ApoE-/- we found 40% and 57% less unstable plaques than ApoE-/- mice.

CONCLUSIONS

Atherosclerotic lesions occur in both, BT and PT, however, the size is smaller in PT, possibly due to the effect of the low-oxygen blood and/or lower blood pressure. GDF-15 is involved in atherosclerotic processes in BT and PT, although different mechanisms (e.g. apoptosis) in these two vessels seem to exist.

Effect of supervised exercise training on exercise capacity, pulmonary function and growth differentiation factor 15 levels in patients with interstitial lung disease: A preliminary study

BACKGROUND: Interstitial lung disease is characterized by exertion dyspnea, exercise limitation and reduced quality of life. The role of exercise training in this diverse patient group is unclear. The growth differentiation factor 15 (GDF15) is a stress-sensitive circulating factor that regulates systemic energy balance and could be a possible biomarker in interstitial lung disease. OBJECTIVE: To evaluate the effect of supervised exercise (endurance and resistance) training (SET) on exercise capacity, pulmonary function parameters and GDF15 levels in patients with interstitial lung disease (PwILD). METHODS: In this non-randomized case-control trial, the experimental group comprised of 10 PwILD (7 women and 3 men) while the control group consisted of of 18 apparently healthy participants s 11 women and 7 men). All subjects completed an 8-week supervised exercise training program, at a rate of twice a week. Dyspnea was evaluated using the Shortness of Breath Respiratory Questionnaire. Exercise capacity was measured using the 6-min walk test while the heart rate (HR) was monitored before and after the exercise training. GDF15 levels were measured by Enzyme-Linked Immunosorbent Assay (ELISA). RESULTS: PwILD had significantly shorter 6-min walk distance than the control subjects at both the 1st and the 15th visit. However, both groups improved significantly in this test. The change (pre to post-exercise) in HR value was smaller in PwILD compared to the controls. Moreover, PwILD had higher Shortness of Breath Respiratory Questionnaire score than controls. While the mean pre-post GDF15 change values in both groups remained statistically unchanged the GDF15 values of the PwILD patients were significantly higher compared to the controls with respect to pre-post exercise training respectively. CONCLUSION: Supervised exercise training did not affect GDF15 levels in both patient and control groups but its values in PwILD were significantly higher compared to those of controls (p⩽0.05). The exercise capacity and dyspnea in these patients improved after exercise training program.

The relationships between serum heart-type fatty acid-binding protein and right ventricular echocardiographic indices in chronic obstructive pulmonary disease

BACKGROUND

Heart-type Fatty Acid-Binding Protein (H-FABP) has been used in the diagnosis of myocardial damage. In this study, we assessed the relationships between serum H-FABP as a marker of cardiac injury and right ventricle (RV) echocardiographic indices in patients with stable COPD.

MATERIALS AND METHODS

In this case-control study, 84 participants were investigated (50 COPD patients and 34 healthy subjects). After obtaining consent, 3 mL of fasting whole blood sample was collected from each of the participants to test their serum H-FABP. Echocardiography was performed on all participants by cardiologists.

RESULTS

Serum H-FABP was found to be significantly correlated with smoking history (P < 0.01), Systolic Pulmonary Artery Pressure (S-PAP), RV Wall Thickness (RV-WT), and Tricuspid annulus posts systolic excursion (TAPSE) (P < 0.01 for all). RV Basal Diameter (RV-BD), RV Mid Diameter (RV-MD), and Fractional area change percentage (FAC%) were not observed to have any correlation with serum H-FABP. Also, the comparative analysis showed statistically significant differences between mean RV-MD (P < 0.001), RV-BD, FAC%, S-PAP, RV-WT (P < 0.001), and TAPSE (P < 0.05) of patients at different GOLD stages. There was a significant correlation between the adjusted serum level of H-FABP and the airflow limitation based on FEV1 (P < 0.001).

CONCLUSION

The correlation between serum H-FABP and RV echocardiographic indices such as S-PAP, RV-WT, and TAPSE, can be related to RV function in COPD patients. Moreover, RV echocardiographic indices are significantly correlated with the severity of COPD as classified in various GOLD stages.

GDF-15 in Pulmonary and Critical Care Medicine

GDF-15 (growth differentiation factor 15) acts both as a stress-induced cytokine with diverse actions at different body sites and as a cell-autonomous regulator linked to cellular senescence and apoptosis. For multiple reasons, this divergent transforming growth factor-β molecular superfamily member should be better known to pulmonary researchers and clinicians. In ambulatory individuals, GDF-15 concentrations in peripheral blood are an established predictive biomarker of all-cause mortality and of adverse cardiovascular events. Concentrations upon admission of critically ill patients (without or with sepsis) correlate with organ dysfunction and independently predict short- and long-term mortality risk. GDF-15 is a major downstream mediator of p53 activation, but it can also be induced independently of p53, notably by nonsteroidal antiinflammatory agents. GDF-15 blood concentrations are markedly elevated in adults and children with pulmonary hypertension. Concentrations are also increased in chronic obstructive pulmonary disease, in which they contribute to mucus hypersecretion, airway epithelial cell senescence, and impaired antiviral defenses, which together with murine data support a role for GDF-15 in chronic obstructive pulmonary disease pathogenesis and progression. This review summarizes biological and clinical data on GDF-15 relevant to pulmonary and critical care medicine. We highlight the recent discovery of a central nervous system receptor for GDF-15, GFRAL (glial cell line-derived neurotrophic factor family receptor-α-like), an important advance with potential for novel treatments for obesity and cachexia. We also describe limitations and controversies in the existing literature, and we delineate research questions that must be addressed to determine whether GDF-15 can be therapeutically manipulated in other clinical settings.

The clinical impact of growth differentiation factor-15 in heart disease: A 2019 update

Growth differentiation factor-15 (GDF-15), also known as macrophage inhibitory cytokine-1 (MIC-1) or non-steroidal anti-inflammatory drug-activated gene (NAG-1) has been identified as a biomarker of response to treatment and prognosis in cardiovascular diseases. GDF-15 is a member of the transforming growth factor-β superfamily and is involved in several pathological conditions such as inflammation, cancer, cardiovascular, pulmonary and renal diseases. Cardiac myocytes produce and secrete GDF-15 in response to oxidative stress, stimulation with angiotensin II or proinflammatory cytokines, ischemia, and mechanical stretch. Other cellular sources of GDF-15 production are macrophages, vascular smooth muscle cells, endothelial cells, and adipocytes, which secrete GDF-15 in response to oxidative or metabolic stress or stimulation of proinflammatory cytokines. GDF-15 is induced in hypertrophic and dilated cardiomyopathy after volume overload, ischemia, and heart failure. GDF-15 can be used as a marker of prognosis in patients with cardiovascular disorders, in combination with conventional prognostic factors, such as N-terminal pro B-type natriuretic peptide (NT-proBNP) and high-sensitivity troponin T (hs-TnT).

GDF15 is an epithelial-derived biomarker of idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is the most common and devastating of the interstitial lung diseases. Epithelial dysfunction is thought to play a prominent role in disease pathology, and we sought to characterize secreted signals that may contribute to disease pathology. Transcriptional profiling of senescent type II alveolar epithelial cells from mice with epithelial-specific telomere dysfunction identified the transforming growth factor-β family member, growth and differentiation factor 15 (Gdf15), as the most significantly upregulated secreted protein. Gdf15 expression is induced in response to telomere dysfunction and bleomycin challenge in mice. Gdf15 mRNA is expressed by lung epithelial cells, and protein can be detected in peripheral blood and bronchoalveolar lavage following bleomycin challenge in mice. In patients with IPF, GDF15 mRNA expression in lung tissue is significantly increased and correlates with pulmonary function. Single-cell RNA sequencing of human lungs identifies epithelial cells as the primary source of GDF15, and circulating concentrations of GDF15 are markedly elevated and correlate with disease severity and survival in multiple independent cohorts. Our findings suggest that GDF15 is an epithelial-derived secreted protein that may be a useful biomarker of epithelial stress and identifies IPF patients with poor outcomes.

Pulmonary Embolism in Patients with Acute Exacerbation of Chronic Obstructive Pulmonary Disease

Objective

In most countries, nearly 6% of the adults are suffering from chronic obstructive pulmonary disease (COPD), which puts a huge economic burden on the society. Moreover, COPD has been considered as an independent risk factor for pulmonary embolism (PE). In this review, we summarized the existing evidence that demonstrates the associations between COPD exacerbation and PE from various aspects, including epidemiology, pathophysiological changes, risk factors, clinical features, management, and prognosis.

Data Sources

We searched the terms "chronic obstructive pulmonary disease," "pulmonary embolism," "exacerbations," and "thromboembolic" in PubMed database and collected the results up to April 2018. The language was limited to English.

Study Selection

We thoroughly examined the titles and abstracts of all studies that met our search strategy. The data from prospective studies, meta-analyses, retrospective studies, and recent reviews were selected for preparing this review.

Results

The prevalence of PE in patients with COPD exacerbation varied a lot among different studies, mainly due to the variations in race, sample size, study design, research setting, and enrollment criteria. Overall, whites and African Americans showed significantly higher prevalence of PE than Asian people, and the hospitalized patients showed higher prevalence of PE compared to those who were evaluated in emergency department. PE is easily overlooked in patients with COPD exacerbation due to the similar clinical symptoms. However, several factors have been identified to contribute to the increased risk of PE during COPD exacerbation. Obesity and lower limb asymmetry were described as independent predictors for PE. Moreover, due to the high risk of PE, thromboprophylaxis has been used as an important treatment for hospitalized patients with COPD exacerbation.

Conclusions

According to the previous studies, COPD patients with PE experienced an increased risk of death and prolonged length of hospital stay. Therefore, the thromboembolic risk in patients with acute exacerbation of COPD, especially in the hospitalized patients, should carefully be evaluated.

IL-17A and GDF15 are able to induce epithelial-mesenchymal transition of lung epithelial cells in response to cigarette smoke

Smoking is one of the primary causes of chronic obstructive pulmonary disease (COPD). Sustained active epithelial-mesenchymal transition (EMT) in COPD may explain the core pathophysiology of airway fibrosis and why lung cancer is so common among smokers. Interleukin (IL)-17A and growth/differentiation factor (GDF)15 have been reported to be biomarkers of COPD; however, the role of IL-17A and GDF15 in EMT remains unclear. The aim of the present study was to investigate the role of IL-17A and GDF15 in the pathogenesis of COPD. It was demonstrated that IL-17A and GDF15 are upregulated in patients with COPD, particularly those with a history of smoking. The results also revealed that IL-17A and GDF15 expression was negatively correlated with the epithelial marker epithelial-cadherin and positively correlated with the mesenchymal marker vimentin. Furthermore, treatment with cigarette smoke extract or IL-17A induced GDF15 expression. Combined treatment with IL-17A and GDF15 induced EMT in human small epithelial HSAEpiC cells in vitro. Collectively, the results of the present study suggest that IL-17A and GDF15-induced EMT serves an important role in the pathology of COPD.

Growth differentiation factor-15 is a predictor of important disease outcomes in patients with COPD

Increased levels of growth differentiation factor-15 (GDF15) are associated with cachexia, cardiovascular disease and all-cause mortality. The role of GDF15 in chronic obstructive pulmonary disease (COPD) is unknown.

The study included 413 patients with COPD from the Bergen COPD Cohort Study. All patients had a forced expiratory volume in 1 s (FEV1) <80% predicted, a FEV1 to forced vital capacity (FVC) ratio <0.7 and a history of smoking. Spirometry, fat free mass index, blood gases and plasma GDF15 were measured at baseline. Patients were followed for 3 years regarding exacerbations and changes in lung function, and 9 years for mortality. Yearly exacerbation rate, survival and yearly change in FEV1/FVC were evaluated with regression models.

Median plasma GDF15 was 0.86 ng·mL−1 (interquartile range 0.64–1.12 ng·mL−1). The distribution was not normal and GDF15 was analysed as a categorical variable. High levels of GDF15 were associated with a higher exacerbation rate (incidence rate ratio 1.39, 95% CI 1.1–1.74, p=0.006, adjusted values). Furthermore, high levels of GDF15 were associated with higher mortality (hazard ratio 2.07, 95% CI 1.4–3.1, p<0.001) and an increased decline in both FEV1 (4.29% versus 3.25%) and FVC (2.63% versus 1.44%) in comparison to low levels (p<0.01 for both).

In patients with COPD, high levels of GDF15 were independently associated with a higher yearly rate of exacerbations, higher mortality and increased decline in both FEV1 and FVC.

GDF-15 plasma levels in chronic obstructive pulmonary disease are associated with subclinical coronary artery disease

BACKGROUND

Growth differentiation factor-15 (GDF-15), a cytokine associated with cardiovascular mortality, increases during chronic obstructive pulmonary disease (COPD) exacerbations, but any role in stable COPD is unknown. We tested associations between GDF-15 and subclinical coronary atherosclerosis, assessed by coronary artery calcium (CAC) score, in COPD subjects free of clinical cardiovascular disease (CVD).

METHODS

Cross-sectional analysis of COPD participants (GOLD stages 2-4) in the COPDGene cohort without CVD at enrollment, using baseline CAC (from non-EKG-gated chest computed tomography) and plasma GDF-15 (by custom ELISA). We used multinomial logistic modeling of GDF-15 associations with CAC, adjusting for demographics, baseline risk (calculated using the HEART: Personal Heart Early Assessment Risk Tool (Budoff et al. 114:1761-1791, 2006) score), smoking history, measures of airflow obstruction, emphysema and airway disease severity.

RESULTS

Among 694 participants with COPD (47% women, mean age 63.6 years) mean GDF-15 was 1,304 pg/mL, and mean CAC score was 198. Relative to the lower GDF-15 tertile, higher tertiles showed bivariate association with increasing CAC score (mid tertile odds ratio [OR] 1.80, 95% confidence interval [CI] 1.29, 2.51; higher tertile OR 2.86, CI 2.04, 4.02). This association was maintained after additionally adjusting for baseline CVD risk, for co-morbidities and descriptors of COPD severity and impact, markers of cardiac stress (N-terminal pro-B-type natriuretic peptide, troponin T) and of inflammation (Interleukin-6), and in subgroup analysis excluding men, diabetics, current smokers or those with limited ambulation.

CONCLUSIONS

In ever-smokers with COPD free of clinical CVD, GDF-15 contributes independently to subclinical coronary atherosclerosis.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT00608764 . Registered 28 January 2008.