Correlations between osteoprotegerin serum levels and body composition parameters in patients with sleep apnea syndrome and the possible influence on cardiovascular risk

INTRODUCTION

Osteoprotegerin (OPG) is a member of the tumor necrosis factor family and a key regulator in bone turnover; it plays a role in the development of many cardiovascular diseases and may be treated as a marker of vascular damage. Bioelectrical impedance analysis (BIA) is a reliable, non-invasive and effective technique for measuring body composition. The aim of the study was to evaluate correlations between osteoprotegerin serum levels and body composition parameters in sleep apnea patients and their influence on cardiovascular risk.

MATERIAL AND METHODS

A total of 125 patients with newly diagnosed OSA were enrolled in the study (including 34 females). The mean age was 54.48±8.81 years, mean AHI 33.16±20.44/h and mean BMI 33.76±7.18. A control group comprised 59 healthy subjects with mean age of 51.27±12.97 years and mean BMI 29.47±5.42. All subjects underwent a nocturnal respiratory polygraphy and body composition measurements were taken with bioelectrical impedance analysis. OPG serum levels were measured using the enzyme-linked immunosorbent assay (ELISA) method.

RESULTS

In OSA patients OPG correlated negatively with muscle mass percentage (MM%), phase angle, fat free mass percentage (FFM%) and body cell mass percentage (BCM%), while there was a positive correlation between osteoprotegerin and fat mass percentage (FM%). We demonstrated higher OPG serum levels in OSA patients with cardiovascular diseases than in those without comorbidities (4.01 vs 3.46pmol/l, p<0.05).

CONCLUSION

Our findings, combined with previous observations in other diseases, suggest that elevated OPG serum levels together with selected body composition parameters may be helpful in identifying OSA patients with increased cardiovascular risk.

Nocturnal parasympathetic modulation of heart rate in obesity-hypoventilation patients

Heart rate variation (HRV) reflects the activity of the autonomic nervous system. The aim of the study was to analyze HRV in obstructive sleep apnea (OSA) and obesity hypoventilation (OH) patients to answer the question of whether chronic alveolar hypoventilation influences autonomic heart rate regulation. In 41 patients, diagnosed with either 'pure' OSA (n=23, apnea/hypopnea index--AHI: 43.8±18.0 PaCO2≤45 mmHg) or OH syndrome (n=18, AHI 58.7±38.0 PaCO2>46 mmHg), the HRV was analyzed, based on an 8 h ECG recording during sleep. In the OH patients, compared with the OSA patients, there was a globally decreased HRV, with a corresponding decrease in high frequency power in the spectral analysis of HRV and increased low frequency/high frequency ratio (p<0.05), indicating a reduced parasympathetic and increased sympathetic heart rate modulation. We conclude that hypoxemia and hypercapnia of the sleep disordered breathing have an impact on the autonomic heart rate regulation. HRV indices have a potential to become prognostic factors for the development of cardiovascular complications in patients with sleep disordered breathing.

Soluble ligand CD40 and uric acid as markers of atheromatosis in patients with obstructive sleep apnea

The aim of the study was to evaluate the risk of atheromatosis in patients with obstructive sleep apnea (OSA), as based on the concentration of the pro-atherogenic soluble CD40L ligand (sCD40L) in relation to the level of uric acid. The serum levels of sCD40L and uric acid were measured in 79 OSA patients (mean apnea/hypopnea index - AHI 34.4 ± 20.9) and in 40 healthy controls. We found that sCD40L was higher in the OSA patients with hyperuricemia than that in the patients with uric acid in the normal range (sCD40L: 9.0 ng/ml vs. 8.0 ng/ml, respectively, p < 0.05). There was a positive association of sCD40L with AHI (p = 0.01) and a negative one with the mean minimal nocturnal SaO₂(p < 0.05). Uric acid correlated negatively with the mean and minimal SaO₂and positively with the oxygen desaturation index (p < 0.05). OSA patients with hyperuricemia also had a higher prevalence of hypertension and ischemic heart disease. We conclude that OSA patients with increased uric acid concentration have increased risk of atheromatosis, as indicated by a higher level of soluble pro-atherogenic ligand CD40, and a higher prevalence of cardiovascular adverse events.

Efficacy of noninvasive mechanical ventilation in obese patients with chronic respiratory failure

Chronic respiratory failure (CRF) develops in a minority of obese patients. Noninvasive mechanical ventilation (NIMV) is a new optional treatment for such patients. The aim of this study was to evaluate the effectiveness of NIMV in obese patients with CRF. The material of the study consisted of 34 obese patients (body mass index 47.3 ± 7.9 kg/m(2)) with CRF (PaO2 = 6.40 ± 0.93 kPa and PaCO2 = 8.67 ± 2.13 kPa) who were hypoxemic despite an optimal therapy. Thirteen patients had an overlap syndrome (OS) - chronic obstructive pulmonary disease (COPD) coexisting with obstructive sleep apnea syndrome (OSAS) and 21 patients had obesity-hypoventilation syndrome (OHS). Ventilation parameters were determined during polysomnography. The efficacy of NIMV was evaluated on the fifth day and after 1 year's home treatment. We observed a significant increase in the mean blood oxygen saturation during sleep in all patients; the increase was greater in patients with OHS (92.6 ± 1.4 %) than in patients with OS (90.4 ± 1.8 %). There was a significant improvement of diurnal PaO2 and PaCO2 on the fifth day of NIMV (mean PaO2 increase 2.1 kPa and PaCO2 decrease 0.9 kPa) and also after 1 year of home NIMV (mean PaO2 increase 1.9 kPa and PaCO2 decrease 2.4 kPa). Only one patient stopped treatment because of lack of tolerance during the observation period (1-3 years). In conclusion, NIMV is an effective and well tolerated treatment option in obese patients with CRF resulting in a rapid relief of respiratory disorders during sleep and a gradual, long-term improvement of gas exchange during the day, particularly in patients with OHS.

Cyclin A and Cyclin E expression in resected non-small cell lung cancer stage I-IIIA

BACKGROUND

Lung cancer is the leading cause of cancer death in the majority of developed countries. Cyclin E regulates the the G(1)-S phase transition of the cell cycle. Cyclin A increases during the S- and G(2)-phases, and is a regulator of the transition to mitosis.The aim of this study was to evaluate the prognostic significance of cyclin A and cyclin E expression in primary, resected stage I-IIIA non-small cell lung cancer (NSCLC).

MATERIALS AND METHODS

The expression of cyclin A and E was investigated in the paraffin-embedded tumor tissue of 71 patients (53 men and 18 women; age 59.27+/-8.50 years), using a monoclonal antibodies to cyclin A and to cyclin E.

RESULTS

Forty-seven out of 71 (66%) tumor tissue specimens were positive for cyclin A and twenty-six (37%) were positive for cyclin E. In the majority of cases, nuclear staining was apparent. Cyclin A and cyclin E expression was significantly higher in squamous cell carcinoma than in adenocarcinoma (cyclin A: Chi(2) Yates'a 4.6; p=0.032; cyclin E: Chi(2) Yates'a 5.12: p=0.023). The prognostic value of cyclin A and E expression was examinated in all patients and in patients with squamous cell lung cancer and adenocarcinoma and separately for every stage, but no correlations were found.

CONCLUSION

No prognostic value of cyclin A and E expression was found in NSCLC, but significantly higher cyclin A and E expression was found in squamous cell carcinomas than in adenocarcinomas.

[Rhythm of melatonin excretion in obstructive sleep apnea syndrome]

Melatonin is a pineal hormone that regulates sleep and wake status. Melatonin concentrations in blood serum were measured using radioisotope method in 33 males (age 48 +/- 10) with obstructive sleep apnea syndrome. The following melatonin concentrations were measured: 54 +/- 72 pg/ml (9 p.m.) 424 +/- 838 pg/ml (2 a.m.) and 307 +/- 534 pg/ml (6 a.m.). In patients with high peak melatonin concentration (> 200 pg/ml) as compared with the patients with low peak melatonin concentration (< 200 pg/ml) there were higher index of respiratory disorders during sleep (53 +/- 18 vs 38 +/- 20, p < 0.05) and lower minimal SaO2 during sleep apnea (52 +/- 17% vs 70 +/- 10%, p < 0.05); they were also more tired in the morning and were more sleepy during the day (Epworth sleepiness scale 17 +/- 6 vs 11 +/- 6, p < 0.01). In 66% of patients peak melatonin concentration was observed at 2 a.m. In 24% of patients peak melatonin secretion was prolonged to early morning hours.

CONCLUSIONS

In most of patients there is peak melatonin excretion at 2 a.m. Patients with high apnea and hypopnea index and daytime sleepiness have high peak melatonin concentrations.

[Pulmonary alveolar microlithiasis in a patient with urolithiasis and cholelithiasis]

49 years old woman was admitted to Pulmonary Ward because of respiratory and cardiac failure. Six years earlier she was surgically treated because of urolithiasis and at this time disseminated lesions in both lungs were revealed. Biopsy made during transbronchial procedure showed microlithiasis. She had'nt any respiratory symptoms during 6 years. Now she had PaO2 = 36 mmHg and massive infiltrations in whole lungs. Palliative therapy with diuresis, cardiac drugs and oxygen therapy diminished symptoms of respiratory and cardiac failure.

[Lipoid pneumonia]

The authors describe in the article etiology, histopathological features, clinical picture and diagnostics of endogenous and exogenous lipoid pneumonia. The advantages of broncho-alveolar fluid examination and computed tomography in the diagnostics were emphasized.