Obstructive sleep apnea and chronic kidney disease: open questions on a potential public health problem

The potential of tRF-21-U0EZY9X1B plasmatic level as a biomarker of children with obstructive sleep apnea-hypopnea syndrome

PURPOSE

We investigated changes in plasma transfer RNA related fragments (tRF) in children with obstructive sleep apnea-hypopnea syndrome (OSAHS) and the potential value as a disease marker.

METHODS

Firstly, we randomly selected five plasma samples from the case group and the control group for high-throughput RNA sequencing. Secondly, we screened one tRF with different expression between the two groups, amplified it by quantitative reverse transcription-PCR (qRT-PCR) and sequenced the amplified product. After confirming that the qRT-PCR results were consistent with the sequencing results and the sequence of the amplified product contained the original sequence of the tRF, we performed qRT-PCR on all samples. Then we analyzed the diagnostic value of the tRF and its correlation with some clinical data.

RESULTS

A total of 50 OSAHS children and 38 control children were included in this study. There were significant differences in height, serum creatinine (SCR) and total cholesterol (TC) between the two groups. The plasma expression levels of tRF-21-U0EZY9X1B (tRF-21) were significantly different between the two groups. Receiver operating characteristic curve (ROC) showed that it had valuable diagnostic index, with area under the curve (AUC) of 0.773, 86.71% and 63.16% sensitivity and specificity.

CONCLUSIONS

The expression levels of tRF-21 in the plasma of OSAHS children decreased significantly which were closely related to hemoglobin, mean corpuscular hemoglobin, triglyceride and creatine kinase-MB, may become novel biomarkers for the diagnosis of pediatric OSAHS.

Particularities of Older Patients with Obstructive Sleep Apnea and Heart Failure with Mid-Range Ejection Fraction

Background and objectives: Obstructive sleep apnea syndrome (OSAS) and heart failure (HF) are increasing in prevalence with a greater impact on the health system. The aim of this study was to assess the particularities of patients with OSAS and HF, focusing on the new class of HF with mid-range ejection fraction (HFmrEF, EF = 40%-49%), and comparing it with reduced EF (HFrEF, EF < 40%) and preserved EF (HFpEF, EF ≥ 50%). Materials and Methods: A total of 143 patients with OSAS and HF were evaluated in three sleep labs of "Victor Babes" Hospital and Cardiovascular Institute, Timisoara, Western Romania. We collected socio-demographic data, anthropometric sleep-related measurements, symptoms through sleep questionnaires and comorbidity-related data. We performed blood tests, cardio-respiratory polygraphy and echocardiographic measurements. Patients were divided into three groups depending on ejection fraction. Results: Patients with HFmrEF were older (p = 0.0358), with higher values of the highest systolic blood pressure (mmHg) (p = 0.0016), higher serum creatinine (p = 0.0013), a lower glomerular filtration rate (p = 0.0003), higher glycemic levels (p = 0.008) and a larger left atrial diameter (p = 0.0002). Regarding comorbidities, data were presented as percentage, HFrEF vs. HFmrEF vs. HFpEF. Higher prevalence of diabetes mellitus (52.9 vs. 72.7 vs. 40.2, p = 0.006), chronic kidney disease (17.6 vs. 57.6 vs. 21.5, p < 0.001), tricuspid insufficiency (76.5 vs. 84.8 vs.59.1, p = 0.018) and aortic insufficiency (35.3 vs.42.4 vs. 20.4, p = 0.038) were observed in patients with HFmrEF, whereas chronic obstructive pulmonary disease(COPD) (52.9 vs. 24.2 vs.18.3, p = 0.009), coronary artery disease(CAD) (82.4 vs. 6.7 vs. 49.5, p = 0.026), myocardial infarction (35.3 vs. 24.2 vs. 5.4, p < 0.001) and impaired parietal heart kinetics (70.6 vs. 68.8 vs. 15.2, p < 0.001) were more prevalent in patients with HFrEF. Conclusions: Patients with OSAS and HF with mid-range EF may represent a new group with increased risk of developing life-long chronic kidney disease, diabetes mellitus, tricuspid and aortic insufficiency. COPD, myocardial infarction, impaired parietal kinetics and CAD are most prevalent comorbidities in HFrEF patients but they are closer in prevalence to HFmrEF than HFpEF.

Obstructive Sleep Apnea and Inflammation: Proof of Concept Based on Two Illustrative Cytokines

Obstructive sleep apnea syndrome (OSAS) is a markedly prevalent condition across the lifespan, particularly in overweight and obese individuals, which has been associated with an independent risk for neurocognitive, behavioral, and mood problems as well as cardiovascular and metabolic morbidities, ultimately fostering increases in overall mortality rates. In adult patients, excessive daytime sleepiness (EDS) is the most frequent symptom leading to clinical referral for evaluation and treatment, but classic EDS features are less likely to be reported in children, particularly among those with normal body-mass index. The cumulative evidence collected over the last two decades supports a conceptual framework, whereby sleep-disordered breathing in general and more particularly OSAS should be viewed as low-grade chronic inflammatory diseases. Accordingly, it is assumed that a proportion of the morbid phenotypic signature in OSAS is causally explained by underlying inflammatory processes inducing end-organ dysfunction. Here, the published links between OSAS and systemic inflammation will be critically reviewed, with special focus on the pro-inflammatory cytokines tumor necrosis factor α (TNF-α) and interleukin 6 (IL-6), since these constitute classical prototypes of the large spectrum of inflammatory molecules that have been explored in OSAS patients.

Telmisartan attenuates kidney apoptosis and autophagy-related protein expression levels in an intermittent hypoxia mouse model

Purpose

Obstructive sleep apnea (OSA) is associated with renal impairs. As a novel pathophysiological hallmark of OSA, chronic intermittent hypoxia (CIH) enhances apoptosis and autophagy. The present study aims to evaluate the effect of telmisartan on CIH-induced kidney apoptosis and autophagy in a mouse model of OSA.

Materials and methods

Mice were randomly allocated to normoxia, CIH, and CIH+telmisartan groups (n = 12 in each group). The CIH exposure duration was 12 weeks. Mice in the CIH+telmisartan group received telmisartan administration. The terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay and western blotting of Bax and cleaved caspase-3 were conducted for evaluating apoptosis in kidney tissue. While the autophagy-related proteins, beclin-1 and LC3, were also observed via western blotting.

Results

The percentage of apoptotic cell in the CIH group was significantly higher than that of normoxia group; meanwhile, Bax and cleaved caspase-3 protein levels were increased in the CIH group than those of normoxia group (all p < 0.05). Compared with the normoxia group, mice in the CIH group had greater autophagy-related proteins (beclin-1 and LC3) expression. When compared to the CIH group, both the renal apoptosis and autophagy in the CIH+telmisartan group were decreased.

Conclusion

The CIH accelerates renal apoptosis and autophagy levels. Telmisartan ameliorating those levels suggests that it might prevent renal impairs from the CIH in OSA patients.