Diagnostic usefulness of pregnancy-associated plasma protein-A in suspected pulmonary embolism

Oxidative Stress Markers among Obstructive Sleep Apnea Patients

Obstructive sleep apnea (OSA) is a chronic respiratory disorder, which can be present in up to 50% of the population, depending on the country. OSA is characterized by recurrent episodes of partial or complete obstruction of the upper airways with consistent movement of the respiratory musculature during sleep. Apneas and hypopneas can lead to a decrease in oxygen saturation, an increase in carbon dioxide in the blood, and subsequent arousals and sleep fragmentation caused by repetitive activation of the central nervous system. As a consequence, intermittent hypoxemia and consequent reoxygenation result in the production of reactive oxygen species, leading to systematic oxidative stress, which is postulated to be a key mechanism of endothelial dysfunction and increased risk for cardiovascular disorders in patients with OSA. In this review, various biomarkers of oxidative stress, including high-sensitivity C-reactive protein, pregnancy-associated plasma protein-A, superoxide dismutase, cell-free DNA, 8-hydroxy-2-deoxyguanosine, advanced oxidation protein products, lipid peroxidation products, receptor for advanced glycation end-products, and thioredoxin are discussed. Biomarkers of oxidative stress have the potential to be used to assess disease severity and treatment response. Continuous positive airway pressure (CPAP) is one of the most common noninvasive treatments for OSA; it keeps the upper airways open during sleep. This reduces episodes of intermittent hypoxia, reoxygenation, and arousal at night. CPAP has been shown to have anti-inflammatory properties and decrease oxidative stress. The administration of certain compounds, like vitamins A, C, and E as well as N-acetylcysteine and allopurinol, can decrease oxidative stress markers. However, their role in the treatment of OSA remains unclear.

The Relation between Pregnancy-Associated Plasma Protein A and Obstructive Sleep Apnea Syndrome

Aim

We aimed to investigate the relationship between serum pregnancy-associated plasma protein A (PAPP-A) levels and obstructive sleep apnea syndrome (OSAS).

Materials and Method

44 patients with OSAS and 44 healthy adults were included in this study. The participants having rheumatic or systemic inflammatory disease, advanced liver or kidney failure, diabetes, heart failure, hypertension, pregnancy, prerenal azotemia, known history of coronary artery disease, any pulmonary disease, rhinitis, or atopy, history of major trauma or surgery within the last six 6 months, and inhaled nasal or systemic corticosteroid use or other anti-inflammatory medications and those with <18 years of age were excluded. Serum PAPP-A levels were determined by the Elisa method with the immune sandwich measuring method. Statistical analysis of the study was performed with SPSS 17.0 statistical analysis package program, and p < 0.05 was considered as significant.

Results

Serum PAPP-A levels of patients with OSAS (2.350 ng/ml (0.641–4.796)) were significantly higher (p < 0.001) when compared with healthy controls (0.971 ng/ml (0.109–2.679)). There was a statistically significant difference in serum PAPP-A levels between groups of OSAS patients according to the classification of OSAS severity. Between the groups of patients with OSAS, serum levels of PAPP-A in moderate group was significantly higher when compared with severe OSAS group (p < 0.001). There was positive correlations between PAPP-A levels and night minimum (p=0.042, r=0.309), and average oxygen levels (p=0.006, r=0.407). There was a negative correlation between PAPP-A levels and AHI (p=0.002, r=−0.460).

Conclusion

Higher PAPP-A levels in OSAS patients that were found in this study show inflammatory component in OSAS.

Pregnancy-associated plasma protein-A (PAPP-A) levels in patients with severe allergic asthma are reduced by omalizumab

BACKGROUND

Remodeling is a crucial feature of severe asthma and may be associated with activation of the allergic cascade by immunoglobulin E (IgE). Omalizumab, an anti-IgE monoclonal antibody, effectively targets the severe allergic asthma phenotype. Pregnancy-associated plasma protein-A (PAPP-A) is an insulin-like growth factor binding protein-4 (IGFBP-4) protease, increasing local insulin-like growth factor (IGF)-1 concentrations, which in turn initiating a cascade involved in the regulation of cell growth, differentiation, and proliferation in various tissues. In the present study, we evaluated the effects of omalizumab on serum PAPP-A, IGFBP-4, and IGF-1 levels in subjects with severe allergic asthma.

METHODS

We studied 36 asthmatic subjects and 36 healthy controls. An ultrasensitive enzyme-linked immunosorbent assay (ELISA) kit was used to measure serum PAPP-A levels, and routine commercial ELISA kits were employed to assess serum levels of IGF-1, IGFBP-4 in control subjects and asthmatic subjects before therapy (baseline) and after six months of omalizumab therapy in patients with severe asthma.

RESULTS

Compared to control subjects, serum PAPP-A and IGFB-4 levels were significantly higher in asthmatic subjects (both p values < 0.001). However, the serum IGF-I levels of asthmatic subjects were similar to those of control subjects (p > 0.05). In asthma subjects, 6-month omalizumab treatment significantly decreased the serum PAPP-A (p < 0.001), IGF-I (p = 0.031), and IGFB4 (p = 0.025) levels.

CONCLUSION

PAPP-A level may be a useful biomarker for predicting airway remodeling in patients with severe asthma receiving omalizumab, and may also reflect the response to treatment.

Evaluation of Pregnancy-Associated Plasma Protein-A Levels in Patients with Chronic Obstructive Pulmonary Disease and Associations with Disease Severity

Chronic obstructive pulmonary disease (COPD) represents a systemic disorder characterized by chronic airflow limitation and an increased inflammatory response of the airways. Comorbidities are frequent in COPD and it is crucial to predict these in early stage for adequate management of COPD. Recent studies have reported that elevated levels of pregnancy-associated plasma protein-A (PAPP-A), a zinc-binding metalloproteinase, detected in patients with asthma, lung cancer, and pulmonary embolism and independently associated with cardiovascular events. We aimed to assess serum PAPP-A levels in COPD and the associations between disease severity. The study population consisted of 75 COPD patients and 35 healthy subjects as a control group. PAPP-A levels were measured by using ultrasensitive enzyme-linked immunosorbent assay. Elevated levels of PAPP-A were observed in patients with COPD on comparison with the controls (p = 0.000). The levels in stage 1 (34.73 ± 22.97) and stage 2 (48.29 ± 53.35) were significantly higher than stage 3 (20.58 ± 22.98) and stage 4 (27.36 ± 21.46) (p = 0.049). Increased PAPP-A levels may be a useful marker in management of COPD that seeks to prevent the development of comorbidities such as adverse cardiovascular diseases.