Influence of intermittent hypoxia on the signal transduction pathways to inflammatory response and circadian clock regulation

Factors correlated with excessive daytime sleepiness in patients with Parkinson's disease: A polysomnography study

OBJECTIVE

To explore the factors correlated with excessive daytime sleepiness (EDS) in patients with Parkinson's disease (PD).

METHODS

A total of 239 PD patients were divided into two groups based on the presence of EDS (Epworth Sleepiness Scale score≥10) (PD-EDS vs. PD-non-EDS). Participants underwent an extensive assessment to determine demographic features, disease severity, polysomnography characteristics, and nonmotor symptoms.

RESULTS

Of the 239 patients, 56 patients (23.4%) were classified as having PD combined with EDS. Binary logistic regression analysis showed that fatigue (Fatigue Severity Scale [FSS] score ≥4) (odds ratio [OR] [95% CI] = 4.897 [2.376-10.095], p < .001) and the respiratory-related microarousal index (OR [95% CI] = 2.063 [1.085-3.923], p = .027) were independent risk factors for EDS in PD patients. A priori-determined stratified analysis showed that after adjustment for confounding factors, the association of the respiratory-related microarousal index with EDS was significant (OR = 4.404, 95% CI 1.673-11.592, p trend = .036) in patients with respiratory arousal index scores in the highest quintile compared with those with scores in the lowest quintile.

CONCLUSION

Our data revealed a close association among the respiratory-related microarousal index, FSS scores, and EDS. It can be speculated that fragmented sleep and pathological abnormalities of the central nervous system resulting in changes in arousal are major influencing factors of EDS in PD.

Association between Interleukin-6 and vitamin D serum levels in patients with obstructive sleep apnea syndrome and impact of long-term continuous positive airway pressure therapy on biomarker levels

OBJECTIVE

Hypoxia induces interleukin-6 (IL-6) production in obstructive sleep apnea syndrome (OSAS). Low serum 25 hydroxyvitamin D (25(OH)D) levels have been linked to OSAS susceptibility. Serum 25(OH)D levels have been negatively correlated with serum IL-6 levels in patients with chronic inflammation. No data exist to assess whether there is a correlation between 25(OH)D and IL-6 serum levels in OSAS, while the impact of continuous positive airway pressure (CPAP) therapy on IL-6 or 25(OH)D levels needs further investigation. We aimed to compare the serum 25(OH)D and IL-6 levels between OSAS patients and controls, examine a possible correlation between 25(OH)D and IL-6 levels and the changes of their concentrations after twelve months of CPAP therapy in OSAS patients.

METHODS

15 newly-diagnosed OSAS patients and 15 non-apneic controls were recruited. Serum IL-6 and 25(OH)D levels were measured in the study population at baseline and twelve months after CPAP initiation in OSAS patients.

RESULTS

IL-6 levels were elevated in OSAS patients than controls and were positively and negatively correlated with body mass index (BMI) and minimum oxyhemoglobin saturation (minSpO₂), respectively. Diabetes mellitus, BMI and minSpO₂ independently predicted IL-6 levels. No difference was found in 25(OH)D levels between groups. No correlation between IL-6 and 25(OH)D levels was detected. Effective CPAP therapy did not impact IL-6 or 25(OH)D levels after one year in OSAS patients.

CONCLUSIONS

No correlation between IL-6 and 25(OH)D levels was found. IL-6 levels were significantly elevated in OSAS patients than the controls and positively correlated with BMI, diabetes mellitus, and nocturnal hypoxemia.

Anaesthesia-Induced Transcriptomic Changes in the Context of Renal Ischemia Uncovered by the Use of a Novel Clamping Device

Ischemia is a common cause of acute kidney injury worldwide, frequently occurring in patients undergoing cardiac surgery or admitted to the intensive care unit (ICU). Thus, ischemia-reperfusion injury (IRI) remains one of the main experimental models for the study of kidney diseases. However, the classical technique, based on non-traumatic surgical clamps, suffers from several limitations. It does not allow the induction of multiple episodes of acute kidney injury (AKI) in the same animal, which would be relevant from a human perspective. It also requires a deep and long sedation, raising the question of potential anaesthesia-related biases. We designed a vascular occluding device that can be activated remotely in conscious mice. We first assessed the intensity and the reproducibility of the acute kidney injury induced by this new device. We finally investigated the role played by the anaesthesia in the IRI models at the histological, functional and transcriptomic levels. We showed that this technique allows the rapid induction of renal ischemia in a repeatable and reproducible manner, breaking several classical limitations. In addition, we used its unique specificities to highlight the renal protective effect conferred by the anaesthesia, related to the mitigation of the IRI transcriptomic program.

Altered irisin/BDNF axis parallels excessive daytime sleepiness in obstructive sleep apnea patients

STUDY OBJECTIVES

Obstructive sleep apnea hypopnea syndrome (OSAHS) is a sleep-related breathing disorder, characterized by excessive daytime sleepiness (EDS), paralleled by intermittent collapse of the upper airway. EDS may be the symptom of OSAHS per se but may also be due to the alteration of central circadian regulation. Irisin is a putative myokine and has been shown to induce BDNF expression in several sites of the brain. BDNF is a key factor regulating photic entrainment and consequent circadian alignment and adaptation to the environment. Therefore, we hypothesized that EDS accompanying OSAHS is reflected by alteration of irisin/BDNF axis.

METHODS

Case history, routine laboratory parameters, serum irisin and BDNF levels, polysomnographic measures and Epworth Sleepiness Scale questionnaire (ESS) were performed in a cohort of OSAHS patients (n = 69). Simple and then multiple linear regression was used to evaluate data.

RESULTS

We found that EDS reflected by the ESS is associated with higher serum irisin and BDNF levels; β: 1.53; CI: 0.35, 6.15; p = 0.012 and β: 0.014; CI: 0.0.005, 0.023; p = 0.02, respectively. Furthermore, influence of irisin and BDNF was significant even if the model accounted for their interaction (p = 0.006 for the terms serum irisin, serum BDNF and their interaction). Furthermore, a concentration-dependent effect of both serum irisin and BDNF was evidenced with respect to their influence on the ESS.

CONCLUSIONS

These results suggest that the irisin-BDNF axis influences subjective daytime sleepiness in OSAS patients reflected by the ESS. These results further imply the possible disruption of the circadian regulation in OSAHS. Future interventional studies are needed to confirm this observation.

Pathogenesis of Abnormal Hepatic Lipid Metabolism Induced by Chronic Intermittent Hypoxia in Rats and the Therapeutic Effect of N-Acetylcysteine

BACKGROUND The pathogenesis of chronic intermittent hypoxia (CIH)-induced abnormal hepatic lipid metabolism in rats remains unclear. Here, we investigated the therapeutic effect of N-acetylcysteine (NAC) on abnormal hepatic lipid metabolism. MATERIAL AND METHODS Rats were subjected to hypoxia and NAC treatment, and evaluated in terms of hepatic lipid metabolism, hepatocyte ultrastructure, oxidative stress in hepatocytes, expression of nuclear factor-kappa B (NF-κB) and inflammatory cytokines (IL-1β, IL-6, and TNFα), serum lipoprotein lipase (LPL) levels, and blood lipids (triglycerides and cholesterol). RESULTS Compared to the normoxic control group, animals in the hypoxic model group showed significant body weight gain; abnormal hepatic lipid metabolism; lipid vacuolization; accumulation of lipid droplets; abundant autophagosomes and lysosomes; significant increases in oxidative stress, inflammation level, and blood lipid levels; and significantly reduced LPL levels. Compared to control animals, rats in the treatment group exhibited normal body weight gain, improved lipid metabolism, fewer lipid droplets, alleviated ultrastructural injuries, decreased oxidative stress and inflammation level, as well as elevated LPL and reduced blood lipid levels. CONCLUSIONS The harmful effects of CIH on rat liver are possibly associated with the reactive oxygen species (ROS)/NF-κB signaling pathway. NAC is capable of attenuating lipid metabolism alterations and abnormal body weight gain in the CIH rat model, via a possible mechanism related to inhibition of ROS/NF-κB signaling.

Transcriptome Profiling of the Lungs Reveals Molecular Clock Genes Expression Changes after Chronic Exposure to Ambient Air Particles

The symptoms of asthma, breathlessness, insomnia, etc. all have relevance to pulmonary rhythmic disturbances. Epidemiology and toxicology studies have demonstrated that exposure to ambient air particles can result in pulmonary dysfunction. However, there are no data directly supporting a link between air pollution and circadian rhythm disorder. In the present study, we found that breathing highly polluted air resulted in changes of the molecular clock genes expression in lung by transcriptome profiling analyses in a rodent model. Compared to those exposed to filtered air, in both pregnant and offspring rats in the unfiltered group, key clock genes (Per1, Per2, Per3, Rev-erbα and Dbp) expression level decreased and Bmal1 expression level increased. In both rat dams and their offspring, after continuous exposure to unfiltered air, we observed significant histologic evidence for both perivascular and peribronchial inflammation, increased tissue and systemic oxidative stress in the lungs. Our results suggest that chronic exposure to particulate matter can induce alterations of clock genes expression, which could be another important pathway for explaining the feedbacks of ambient particle exposure in addition to oxidative stress and inflammation.

Gender and the circadian pattern of body temperature in normoxia and hypoxia

Circadian patterns are at the core of many physiological processes, and their disruption can have short- and long-term consequences. This essay focuses on one of the best known patterns, the daily oscillation of body temperature (Tb), and the possibility of its difference between genders. From human and animal studies globally considered, the tentative conclusion is reached that differences in Tb circadian pattern between genders are very small and probably limited to the timing of the rhythm, not to its amplitude. Such similarity between genders, despite the differences in hormonal systems, presumably testifies to the importance that the Tb circadian pattern plays in the economy of the organism and its survival against environmental challenges. The second part of the article presents some previously unpublished experimental data from behaving male and female rats during hypoxia in synchronized conditions. In adult rats hypoxia (10.5% O₂ for three days) caused a profound drop of the Tb daily oscillations; by day 3 they were 55% (♀) and 22% (♂) of the normoxic amplitudes, with a statistically significant gender difference. In pre-puberty rats (26-day old) hypoxia caused a major disruption of the circadian pattern qualitatively similar to the adults but not different between genders. Hence, on the basis of this preliminary set of data, it seems that sex-hormones may be a factor in how the Tb daily pattern responds to hypoxia. The implications of the effects of hypoxia on the circadian patterns, and the possibility that such effects may differ between genders, are matters that could have biological and clinical implications and deserve further investigations.

Assessment of the role of serum ischemia-modified albumin in obstructive sleep apnea in comparison with interleukin-6

OBJECTIVES

There is limited and contradictory information regarding the role of serum ischemia-modified albumin (IMA) in obstructive sleep apnea (OSA). In this study we examine the effects of OSA and obesity on IMA and interleukin-6 (IL-6), and detect whether IMA and IL-6 may be potential biomarkers in OSA.

METHODS

Fifty-one males who underwent all night polysomnography test were included into the study. Body-mass index (BMI) and apnea-hypopnea index (AHI) of all patients were determined. Serum IMA and IL-6 levels, erythrocyte sedimentation rate (ESR), complete blood count, routine blood biochemistry and thyroid function tests were performed.

RESULTS

Mean IMA [0.36 (± 0.04) U/ml, 0.89 (± 0.15) U/ml], mean IL-6 [1.01 (± 0.19) pg/ml, 2.02 (± 1.19) pg/ml] and mean ESR [4.14 (± 2.5) mm/h, 14.35 (± 13.7) mm/h] levels showed significant difference between non-OSA and OSA groups (P = 0.005, P < 0.001, P < 0.001, respectively). Sensitivity of IMA in distinction of non-OSA/OSA was equal to IL-6 and higher than ESR. IMA was also a stronger predictive factor than IL-6 and ESR in the evaluation of OSA groups (severe/mild/moderate OSA and non-OSA). IMA was the sole distinctive biomarker in assessment of obese and non-obese cases. IMA correlated with IL-6, AHI and ESR.

CONCLUSION

Serum IMA may be a valuable oxidative stress indicator for OSA and could act as a better biomarker than IL-6 for reflecting the presence and the severity of OSA.

Incidence and risk of atrial fibrillation in sleep-disordered breathing without coexistent systemic disease

BACKGROUND

Although the link between sleep-disordered breathing (SDB) and atrial fibrillation (AF) has been reported, a population-based longitudinal cohort study was lacking. The goal of the present study was to investigate the AF risk carried by SDB, using the National Health Insurance Research Database in Taiwan. METHODS AND RESULTS: From 2000 to 2001, a total of 579,521 patients who had no history of cardiac arrhythmias or significant comorbidities were identified. Among them, 4,082 subjects with the diagnosis of SDB were selected as the study group, and the remaining 575,439 subjects constituted the control group. The study endpoint was the occurrence of new-onset AF. During a follow-up of 9.2±2.0 years, there were 4,023 patients (0.7%) experiencing new-onset AF. The occurrence rate of AF was higher in patients with SDB compared to those without it (1.3% vs. 0.7%, P<0.001). The AF incidences were 1.38 and 0.76 per 1,000 person-years for patients with and without SDB, respectively. After anadjustment for age and sex, SDB was a significant risk factor of AF with a hazard ratio of 1.536. The AF risk increased with increasing clinical severity of SDB, represented by the requirement of continuous positive airway pressure use.

CONCLUSIONS

SDB itself, without the coexistence of other systemic diseases, was a risk factor of AF.

Infection- and procedure-dependent effects on pulmonary gene expression in the early phase of influenza A virus infection in mice

Background

Investigating the host response in the early stage of influenza A virus (IAV) infection is of considerable interest. However, it is conceivable that effects due to the anesthesia and/or intranasal infection procedure might introduce artifacts. We therefore aimed to evaluate the effects of anesthesia and/or intranasal infection on transcription of selected pulmonary mRNAs in two inbred mouse strains with differential susceptibility to IAV infection.

Results

DBA/2J and C57BL/6J mice were evaluated in a time course experiment in which lung tissue was sampled after 6, 12, 18, 24, 48 and 120 h. After anesthesia with ketamine and xylazine, a suspension of mouse-adapted IAV strain PR8_Mun in 20 μl sterile buffer, or 20 μl sterile buffer only, was instilled intranasally. The mice receiving anesthesia and PBS only were designated the “mock treatment” group. Pulmonary expression of 10 host mRNAs (Fos, Retnla, Irg1, Il6, Il1b, Cxcl10, Stat1, Ifng, Ifnl2, and Mx1) and viral hemagglutinin (HA) mRNA were determined at the designated time points. As expected, weight loss and viral replication were greater in the DBA/2J strain (which is more susceptible to IAV infection). Four mRNAs (Retnla, Irg1, Il6, and Cxcl10) were procedure-dependently regulated in DBA/2J mice between 6 and 24 h, and two (Retnla and Il6) in C57BL/6J mice, although to a lesser extent. All 10 mRNAs rose after infection, but one (Fos) only in DBA/2J mice. These infection-dependent effects could be separated from procedure-dependent effects beginning around 12 h in DBA/2J and 18 h in C57BL/6J mice. The interferon-related mRNAs Stat1, Ifng, Infl2, and Mx1 were unaffected by mock treatment in either mouse strain. Mx1 and Infl2 correlated best with HA mRNA expression (r = 0.97 and 0.93, respectively, in DBA/2J).

Conclusions

These results demonstrate effects of the anesthesia and/or intranasal infection procedure on pulmonary gene expression, which are detectable between approximately 6 and 24 h post procedure and vary in intensity and temporal evolution depending on the mouse strain used. Mock infection controls should be included in all studies on pulmonary gene expression in the early phase of infection with IAV and, likely, other respiratory pathogens.

Immune markers in breast milk and fetal and maternal body fluids: a systematic review of perinatal concentrations

Breastfeeding represents the continued exposure of the infant to the maternal immune environment.Uterine, perinatal, and postnatal exposure to immune factors may contribute to an infant’s risk of developing immune-mediated disorders, including allergies. A PubMed search was conducted to review studies in humans and analyze concentrations of immune markers (TGF-beta, IFN-gamma, eotaxin, CCL5, CXCL10, TNF-alpha, MCP-1, IL-1beta, IL-4, IL-5, IL-6,IL-8, IL-10, IL-12, IL-13, sCD14, sIgA, IgG4, IgM) found in maternal serum, amniotic fluid, cord serum, colostrum, transition and mature milk. Concentrations of immune markers showed large variations across samples and studies. Reports documented conflicting results. Small sample sizes, differences in population characteristics, inconsistent sample collection times, and various sample collection and measurement methods may have led to wide variations in the concentrations of immune markers. Studies analyzing the associations between immune markers in maternal fluids and infant allergies remain inconclusive because of gaps in knowledge and a lack of standardized methods.

Asthma: Chronopharmacotherapy and the molecular clock

Bronchial asthma is characterized by chronic airways inflammation and reversible airflow limitation. In patients with asthma, symptoms generally worsen during the early hours of the morning, and pulmonary function often deteriorates at the same time, suggesting a role for chronopharmacotherapy. Several drugs for asthma have been developed based on chronopharmacology. Most medications employed for the chronotherapy of asthma are administered once at night with the goal of preventing chronic airway inflammation or development of airflow limitation. In addition to bronchodilators, the inhaled glucocorticosteroid ciclesonide is now available with once-daily dosing, which also improves patients' compliance. Numerous investigations have demonstrated the usefulness of chronotherapy for asthma, especially for patients with nocturnal asthma. This review focuses on chronotherapy of asthma, and also provides a molecular biological explanation for the influence of asthma medications on the clock genes.