Circulating levels of mitochondrial oxidative stress-related peptides MOTS-c and Romo1 in stable COPD: A cross-sectional study

Background

MOTS-c and Romo1 are mitochondrial peptides that are modulated by oxidative stress. No previous studies have explored circulating levels of MOTS-c in patients with chronic obstructive pulmonary disease (COPD).

Methods

We enrolled 142 patients with stable COPD and 47 smokers with normal lung function in an observational cross-sectional study. We assessed serum levels of both MOTS-c and Romo1 and associated these findings with clinical characteristics of COPD.

Results

Compared with smokers with normal lung function, patients with COPD had lower levels of MOTS-c (p = 0.02) and higher levels of Romo1 (p = 0.01). A multivariate logistic regression analysis revealed that above-median MOTS-c levels were positively associated with Romo1 levels (OR 1.075, 95% CI 1.005-1.150, p = 0.036), but no association was found with other COPD characteristics. Below-median levels of circulating MOTS-c were associated with oxygen desaturation (OR 3.25 95% CI 1.456-8.522, p = 0.005) and walking <350 meters (OR 3.246 95% CI 1.229-8.577, p = 0.018) in six-minute walk test. Above-median levels of Romo1 were positively associated with current smoking (OR 2.756, 95% CI 1.133-6.704, p = 0.025) and negatively associated with baseline oxygen saturation (OR 0.776 95% CI 0.641-0.939, p = 0.009).

Conclusions

Reduced levels of circulating MOTS-c and increased levels of Romo1 were detected in patients diagnosed with COPD. Low levels of MOTS-c were associated with oxygen desaturation and poorer exercise capacity using 6 min walk test. Romo1 was associated with current smoking and baseline oxygen saturation.

Trial registration

www.clinicaltrials.gov; No.: NCT04449419; URL: www.clinicaltrials.gov. Date of registration: June 26, 2020.

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.

Associations of serum sclerostin levels with body composition, pulmonary function, and exacerbations in COPD patients

BACKGROUND

In COPD, the bronchial epithelium shows a pathologically activated Wnt pathway. Sclerostin (SOST) is a secreted glycoprotein that is associated with bone metabolism and blocks the Wnt pathway. We hypothesized that low sclerostin levels might be associated with lung function and COPD exacerbations in patients.

METHODS

We studied 139 outpatients with stable COPD and normal kidney function. We assessed the serum levels of SOST and bone metabolism parameters, body composition, clinical characteristics and lung function at baseline. We followed the patients prospectively for 12 months after enrolment. Moderate exacerbations and hospital admissions were recorded during follow-up.

RESULTS

The serum SOST levels were 23.98±7.6 pmol/l (men: 25.5±7.7 pmol/l, women: 20.3±5.9 pmol/l (p < 0.001)). SOST showed correlations with age (r = 0.36), FFMI (r = 0.38), FEV1 (r = 0.27), DLCO (r = 0.39), 6MWD (r = 0.19) and CAT (r = -0.24). In multivariate linear regression analysis, only age (beta=0.264) and FFMI (beta=1.241) remained significant. SOST showed a significant negative correlation with serum phosphorus (r = -0.29). Cox proportional risk analysis indicated that patients in the lower tertile of SOST levels were at higher risk of moderate COPD exacerbation (HR 2.015, CI95% 1.136-3.577, p = 0.017) and hospital admission due to COPD (HR 5.142, CI95% 1.380-19.158, p = 0.015) than the rest of the patients.

CONCLUSIONS

SOST levels are associated with body composition and lung function in patients with COPD. Furthermore, lower SOST levels predict a higher risk of exacerbations and hospitalization.

A new, three-dimensional approach to the GOLD COPD assessment tool

BACKGROUND

The 2-dimensional, 4-quadrant 2017 Global Initiative for Chronic Obstructive Lung Disease (GOLD) COPD A-D assessment tool (GOLD₂₀₁₇) does not include lung function variables to classify patients into different risk groups. The previous 2011 tool (GOLD₂₀₁₁) classified cases in the upper-quadrants (higher risk groups) regardless of whether they had a history of exacerbations or worse lung function. We hypothesized that a modified, three-dimensional classification (GOLD_3D) that separately includes assessment of lung function and exacerbations history would improve the ability to predict adverse events.

METHODS

A total of 1303 COPD patients were included in a historical cohort study. The ability of GOLD_3D to predict outcomes (all-cause death and hospitalizations due to severe exacerbation) was compared with GOLD₂₀₁₇ and GOLD₂₀₁₁.

RESULTS

Mean follow-up was 45.0 ± 28.0 months. Two hundred and twenty-eight patients (17.5%) died and 337 (25.9%) subjects suffered at least a severe exacerbation that required hospital admission. The area under the receiver-operating characteristics curve for mortality prediction was slightly but significantly higher for GOLD_3D than for GOLD₂₀₁₁. The area under the curve for prediction of severe exacerbations was significantly higher for GOLD_3D than for GOLD₂₀₁₁ and GOLD₂₀₁₇. A worse ventilatory obstruction was associated in most cases with a higher mortality risk and a higher exacerbation risk for the GOLD2017 A-D groups.

CONCLUSIONS

The proposed GOLD_3D classification system upgrades the previous ones, and is advantageous in predicting future adverse events.

High parathyroid hormone predicts exacerbations in COPD patients with hypovitaminosis D

BACKGROUND

Hypovitaminosis D has been linked to deterioration in clinical parameters and lung function in COPD. As a response to low levels of vitamin D serum Parathyroid Hormone (iPTH) is increased in some, but not all, patients. The aim of this study was to determine whether COPD patients with elevated PTH levels are at higher risk of COPD exacerbations and hospitalizations.

METHODS

166 COPD outpatients were randomly preselected. Clinical and analytical characteristics were assessed at baseline. After excluding patients with other conditions known to disturb calcium metabolism 141 patients were identified. Except one, all patients were prospectively followed for 12 months after obtaining the blood samples. Hypovitaminosis D was considered when serum 25(OH)D < 30 ng/mL. Secondary hyperparathyroidism was considered when serum iPTH was higher than normal (50 pg/mL) in patients with hypovitaminosis D. COPD exacerbations and hospital admissions were recorded during the follow-up.

RESULTS

Prevalence of hypovitaminosis D in COPD patients was 89.3%, prevalence of secondary hyperparathyroidism associated with hypovitaminosis D was 22,9%. Cox proportional risk analysis showed that patients belonging to the high iPTH-low 25(OH)D group were at a higher risk of moderate COPD exacerbations (HR 1.81 (CI95% 1.043-3.127), p = 0.035) and hospital admissions (HR 5.45 (CI95% 2.018-14.720), p = 0.002) as compared with those with normal iPTH-low 25(OH)D levels.

CONCLUSIONS

COPD patients with hypovitaminosis D and elevated iPTH have higher risk of moderate exacerbations and hospitalizations than those with hypovitaminosis D and normal iPTH.

Vitamin D nutritional status and vitamin D regulated antimicrobial peptides in serum and pleural fluid of patients with infectious and noninfectious pleural effusions

BACKGROUND

Vitamin D and vitamin D dependent antimicrobial peptides such as Cathelicidin (LL-37) and β-defensin 2 have an important role in innate and adaptative immunity, but their role in pleural effusions has not been studied before.

METHODS

Serum and pleural fluid samples from 152 patients with pleural effusion were collected, corresponding to 45 transudates and 107 exudates, 51 infectious effusions (14 complicated and 37 non-complicated), 44 congestive heart failure effusions and 38 malignant effusions. The levels of 25 OH-vitamin D, 1,25-(OH)2-vitamin D, Vitamin D Binding Protein (VDBP), LL-37 and β-defensin 2, both in serum and pleural fluid were evaluated in this prospective study. Differences between groups were analysed using unpaired t tests or Mann-Whitney tests. Correlations between data sets were examined using Pearson correlation coefficient or Spearman rank correlation coefficient. Diagnostic accuracy was estimated using ROC curve analysis.

RESULTS

Low serum 25 OH vitamin D levels were found in all groups. Infectious effusions (IE) had higher serum and pleural fluid LL-37 levels compared to congestive heart failure or malignant effusions. Among IE, complicated had higher serum and pleural fluid LL-37 levels, and lower serum β-defensin-2 levels. Positive correlations were found between serum 25 OH-vitamin D levels and serum or pleural 1,25-(OH)2-vitamin D levels, and between 1,25-(OH)2-vitamin D and LL-37 serum. Diagnostic accuracy of the different molecules was moderate at best.

CONCLUSIONS

Hypovitaminosis D is highly prevalent in pleural effusions. LL-37 is produced intrapleurally in IE. This production is higher in complicated IE. No evidence of pleural production of β-defensin 2 was found in any of the groups. Diagnostic accuracy of the different molecules is at the best moderate for discriminating different types of effusions.

Effect of piroxicam beta-cyclodextrin complex on experimental inflammation

1. The effectiveness of the inclusion product of piroxicam with beta-cyclodextrin was compared to that of free piroxicam on inflammatory reactions by using three experimental inflammatory models in rats. 2. The inclusion compound showed anti-inflammatory effects similar to those of simple piroxicam on granuloma tissue formation and arthritis induced by complete Freund adjuvant. 3. In carrageenin-induced pleurisy, the piroxicam beta-cyclodextrin reduced leukocyte mobilization more intensely than non-complexed piroxicam. 4. These results suggest that beta-cyclodextrin is a useful tool for improving the efficacy of piroxicam.