Obstructive sleep apnea is associated with increased coronary plaque instability: an optical frequency domain imaging study

[Obstructive sleep apnea in cardiology clinical practice. Epidemiology, diagnosis, and treatment. Observational, cross-sectional, retrospective study]

Objective

To determine the clinical-epidemiological characteristics, diagnostic feasibility of home respiratory polygraphy and treatment of patients with suspected obstructive sleep apnea (OSA) at cardiovascular risk.

Methods

An observational, cross-sectional, descriptive study was conducted in patients seen in a cardiology outpatient service with suspected OSA, from January 2015 to December 2019. The information was obtained from medical records, and a descriptive statistical analysis was applied to this information.

Results

138 files were reviewed; only 8% of the home respiratory polygraphs were discarded, because they did not meet the required quality standards. It was demonstrated that 89% suffered from OSA, 60% moderate to severe; in men after 50 years of age. The main cardiovascular risk factors was hypertension (89%). The most prevalent heart disease was hypertension (52%). Cardiovascular pharmacological treatment was improved in 82% of the cases. Cardiac rehabilitation in 30%, noninvasive mechanical ventilation 41%, fixed modality 33%, and self-adjustable 9%, all with telemetry.

Conclusions

The prevalence and severity of OSA is higher in the presence of risk or established cardiovascular disease. In the presence of clinical suspicion, it is feasible to confirm the diagnosis with home respiratory poligrafy due to the level of precision and the lower infrastructure required. Greater involvement of the cardiologist in the diagnosis and treatment of this disorder is necessary due to the significant risk of cardiovascular disease it represents.

Obstructive sleep apnea is associated with the long-term prognosis of patients in acute coronary syndromes with prior myocardial infarction: Insights from OSA-ACS study

OBJECTIVE

The prognostic significance of obstructive sleep apnea (OSA) in patients with acute coronary syndrome (ACS) according to prior myocardial infarction (MI) remains unclear. We aimed to investigate the association between OSA and long-term cardiovascular outcomes in ACS patients with or without prior MI.

METHODS

We prospectively recruited eligible 2160 ACS patients with portable sleep monitoring in Beijing Anzhen Hospital between June 2015 and January 2020. OSA was defined as an apnea hypopnea index (AHI) ≥15 events/hour. The primary endpoint was major adverse cardiovascular and cerebrovascular event (MACCE), including cardiovascular death, myocardial infarction, stroke, ischemia-driven revascularization, or hospitalization for unstable angina or heart failure.

RESULTS

Among 1927 patients enrolled, 1014 (52.6%) had OSA and 316 (16.4%) had prior MI. During 2.9 (1.5, 3.6) years of follow-up, multivariate analysis showed that OSA was associated with 1.7 times the risk of MACCE in patients with prior MI (50 events [28.2%] vs 24 events [17.3%]; adjusted HR = 1.74, 95%CI 1.04-2.90, P = 0.034), but not in patients without prior MI group (177 events [21.1%] vs 138 events [17.8%]; adjusted HR = 1.19, 95%CI 0.94-1.51, P = 0.15). There was no significant interaction between prior MI and OSA for MACCE (interaction P = 0.14).

CONCLUSIONS

OSA was independently associated with an increased risk of MACCE among ACS patients, particularly among ACS patients with prior MI. Further trials exploring the efficacy of OSA treatment in high-risk patients with ACS characterized by prior MI are warranted.

Association Between Obstructive Sleep Apnea and Cardiovascular Events in Acute Coronary Syndrome Patients With or Without Revascularization - A Prospective Cohort Study

BACKGROUND

The effects of obstructive sleep apnea (OSA) on the prognosis of acute coronary syndrome (ACS) without revascularization remain unclear, so the aim of the present study was to elucidate the association of OSA with subsequent cardiovascular events in ACS patients with and without revascularization.Methods and Results: We prospectively recruited hospitalized ACS patients undergoing sleep monitoring between June 2015 and January 2020. OSA was defined as an apnea-hypopnea index ≥15 events/h. The primary endpoint was a major adverse cardiovascular and cerebrovascular event (MACCE), including cardiovascular death, myocardial infarction, stroke, ischemia-driven revascularization, or hospitalization for unstable angina or heart failure. Among 1,927 patients, 52.6% had OSA and 69.4% underwent revascularization. During a 2.9-year follow-up (1.5-3.6 years), the risk of MACCE was similar in patients with or without revascularization. OSA was an independent predictor of MACCE in the non-revascularization group (22.6% vs. 14.6%; hazard ratio (HR) 1.861; 95% confidence interval (CI) 1.239-2.796; P=0.003) but not in revascularization group (22.3% vs. 19.3%; HR 1.135; 95% CI 0.882-1.460; P=0.324). The incremental risk in the non-revascularization group was attributable to more hospitalizations for unstable angina (14.2% vs. 8.6%; HR 1.896; 95% CI 1.124-3.199; P=0.016).

CONCLUSIONS

For patients with ACS, OSA was independently associated with higher risk of recurrent cardiovascular events among patients without revascularization but not among patients undergoing revascularization. The benefits of suitable OSA treatment for patients without revascularization need further investigation.

International Consensus Statement on Obstructive Sleep Apnea

BACKGROUND

Evaluation and interpretation of the literature on obstructive sleep apnea (OSA) allows for consolidation and determination of the key factors important for clinical management of the adult OSA patient. Toward this goal, an international collaborative of multidisciplinary experts in sleep apnea evaluation and treatment have produced the International Consensus statement on Obstructive Sleep Apnea (ICS:OSA).

METHODS

Using previously defined methodology, focal topics in OSA were assigned as literature review (LR), evidence-based review (EBR), or evidence-based review with recommendations (EBR-R) formats. Each topic incorporated the available and relevant evidence which was summarized and graded on study quality. Each topic and section underwent iterative review and the ICS:OSA was created and reviewed by all authors for consensus.

RESULTS

The ICS:OSA addresses OSA syndrome definitions, pathophysiology, epidemiology, risk factors for disease, screening methods, diagnostic testing types, multiple treatment modalities, and effects of OSA treatment on multiple OSA-associated comorbidities. Specific focus on outcomes with positive airway pressure (PAP) and surgical treatments were evaluated.

CONCLUSION

This review of the literature consolidates the available knowledge and identifies the limitations of the current evidence on OSA. This effort aims to create a resource for OSA evidence-based practice and identify future research needs. Knowledge gaps and research opportunities include improving the metrics of OSA disease, determining the optimal OSA screening paradigms, developing strategies for PAP adherence and longitudinal care, enhancing selection of PAP alternatives and surgery, understanding health risk outcomes, and translating evidence into individualized approaches to therapy.

Atherosclerotic plaque in individuals without known cardiovascular disease but with established obstructive sleep apnea and at high risk of obstructive sleep apnea

Objectives

In a large U.S. cohort free of CVD evaluated by coronary computed CT angiography, we aimed to assess the association between established / high risk of Obstructive Sleep Apnea (OSA) and coronary plaque.

Background

There are limited data available depicting the association between established / high risk of OSA and the presence of coronary plaque in a population-based sample free from CVD.

Methods

Cross-sectional data from 2359 participants enrolled in the Miami Heart Study (MiHeart) who underwent coronary CT angiography was used for this study. The Berlin questionnaire was used to stratify patients as having high or low risk of OSA. Multiple multivariable logistic regression analyses were conducted to investigate the association between the risk of developing OSA with the presence, volume, and composition of plaque.

Results

According to the Berlin questionnaire, 1559 participants were (66.1%) at low risk of OSA and 800 patients (33.9%) with established / high risk of OSA. Plaque characterization on CCTA revealed a greater incidence of any possible plaque composition in the established / high risk of OSA category (59.6% vs. 43.5%) compared to the low risk of OSA cohort. In logistic regression models, after adjusting for demographics and cardiovascular risk factors, a significant association could still be noted between established / high risk of OSA and any coronary plaque on CCTA (OR=1.31, CI 1.05, 1.63, p = 0.016). Subgroup analysis in the Hispanic population also portrayed a significant association between established / high risk of OSA and the presence of coronary plaque on CCTA (OR = 1.55 CI 1.13, 2.12, p = 0.007).

Conclusion

After accounting for CVD risk factors, individuals at established / high risk of OSA have a higher likelihood of the presence of coronary plaque. Future studies should focus on OSA presence or risk, OSA severity, and the longitudinal consequences of coronary atherosclerosis.

Clinical outcomes and plaque characteristics in patients with coronary artery disease and concomitant sleep-disordered breathing treated by continuous positive airway pressure

BACKGROUND

Sleep-disordered breathing (SDB) is a risk factor for recurrent adverse events in patients with coronary artery disease (CAD). However, the prognosis of continuous positive alveolar pressure (CPAP) treatment for SDB with CAD remains unknown.

METHODS

A total of 281 consecutive patients with stable CAD requiring percutaneous coronary intervention (PCI) were included and classified into three groups according to the concomitance of SDB and CPAP treatment (untreated SDB group, n = 61; CPAP-SDB group, n = 24; and non-SDB group, n = 138). The incidence of major adverse cardiac and cerebrovascular events (MACCEs) within a year after PCI was compared between the three groups. The characteristics of the culprit plaques, including macrophage accumulation, were further assessed using optical coherence tomography.

RESULTS

The incidence of MACCEs was significantly different among the three groups (p = 0.037), with the highest incidence in the untreated-SDB group (22.9%) and 8.3% and 10.1% in the CPAP-SDB and non-SDB groups, respectively. The incidence of MACCEs at 1 year was significantly lower in patients with appropriate CPAP use than that in inadequately treated patients with SDB (0.0 vs. 22.5%, p = 0.048). Macrophage accumulation differed significantly among the three groups, with the highest accumulation in the untreated SDB group.

CONCLUSIONS

CPAP treatment for SDB may be associated with a lower incidence of MACCEs following PCI and a lower prevalence of macrophages in the culprit plaques.

Salidroside Ameliorated Intermittent Hypoxia-Aggravated Endothelial Barrier Disruption and Atherosclerosis via the cAMP/PKA/RhoA Signaling Pathway

Background: Endothelial barrier dysfunction plays a key role in atherosclerosis progression. The primary pathology of obstructive sleep apnea-hypopnea syndrome is chronic intermittent hypoxia (IH), which induces reactive oxygen species (ROS) overproduction, endothelial barrier injury, and atherosclerosis. Salidroside, a typical pharmacological constituent of Rhodiola genus, has documented antioxidative, and cardiovascular protective effects. However, whether salidroside can improve IH-aggravated endothelial barrier dysfunction and atherosclerosis has not been elucidated.

Methods and results: In normal chow diet-fed ApoE^−/− mice, salidroside (100 mg/kg/d, p. o.) significantly ameliorated the formation of atherosclerotic lesions and barrier injury aggravated by 7-weeks IH (21%–5%–21%, 120 s/cycle). In human umbilical vein endothelial cells (HUVECs), exposure to IH (21%–5%–21%, 40 min/cycle, 72 cycles) decreased transendothelial electrical resistance and protein expression of vascular endothelial cadherin (VE-cadherin) and zonula occludens 1. In addition, IH promoted ROS production and activated ras homolog gene family member A (RhoA)/Rho-associated protein kinase (ROCK) pathway. All of these effects of IH were reversed by salidroside. Similar to salidroside, ROCK-selective inhibitors Y26732, and Fasudil protected HUVECs from IH-induced ROS overproduction and endothelial barrier disruption. Furthermore, salidroside increased intracellular cAMP levels, while the PKA-selective inhibitor H-89 attenuated the effects of salidroside on IH-induced RhoA/ROCK suppression, ROS scavenging, and barrier protection.

Conclusion: Our findings demonstrate that salidroside effectively ameliorated IH-aggravated endothelial barrier injury and atherosclerosis, largely through the cAMP/PKA/RhoA signaling pathway.

Obstructive sleep apnea during the chronic stroke recovery period: Comparison between primary haemorrhagic and ischaemic events

The present study retrospectively determined the incidence of obstructive sleep apnea (OSA) after a primary haemorrhagic event compared to an ischaemic stroke during the post-acute recovery period ( x ¯ >3 months). Consideration of medications taken during the sleep evaluation provided additional information on the association between OSA and pathophysiological conditions that may increase the risk of a repeated cardiovascular event. The medical records from 103 patients that underwent a type I fully attended overnight polysomnography as a standard evaluation procedure at a rehabilitation facility were reviewed. Diagnosis of ischaemic or primary haemorrhagic stroke was obtained from a neurological report that was typically confirmed by imaging. Medications taken at the time of the sleep study were documented. Age-adjusted assessment of sleep-disordered breathing revealed a higher incidence of apnea and hypopnea in the ischaemic stroke group (p < 0.005). Patients with ischaemic stroke were also more likely to have severe OSA (p < 0.005). In comparison, a higher percentage of patients with haemorrhagic stroke had an apnea-hypopnea index <5 events/hr (p < 0.005). Those with an ischaemic stroke were taking more lipid lowering agents (p < 0.05). Results suggest that apnea is less prevalent after a haemorrhagic stroke, independent of hypertension, compared to an ischaemic stroke. An increase in predictive values for OSA was observed for indicators of diabetes (p < 0.05). These data indicate that it is relevant to consider stroke type when determining the risk of OSA during the chronic recovery period thus facilitating new strategies for stroke recurrence prevention.

Sleep Disordered Breathing and Cardiovascular Disease: JACC State-of-the-Art Review

Sleep disordered breathing causes repetitive episodes of nocturnal hypoxemia, sympathetic nervous activation, and cortical arousal, often associated with excessive daytime sleepiness. Sleep disordered breathing is common in people with, or at risk of, cardiovascular (CV) disease including those who are obese or have hypertension, coronary disease, heart failure, or atrial fibrillation. Current therapy of obstructive sleep apnea includes weight loss (if obese), exercise, and positive airway pressure (PAP) therapy. This improves daytime sleepiness. Obstructive sleep apnea is associated with increased CV risk, but treatment with PAP in randomized trials has not been shown to improve CV outcome. Central sleep apnea (CSA) is not usually associated with daytime sleepiness in heart failure or atrial fibrillation and is a marker of increased CV risk, but PAP has been shown to be harmful in 1 randomized trial. The benefits of better phenotyping, targeting of higher-risk patients, and a more personalized approach to therapy are being explored in ongoing trials.

Obstructive sleep apnea increases the risk of cardiovascular damage: a systematic review and meta-analysis of imaging studies

BACKGROUND

We aimed to perform a systematic review and meta-analysis of the association between obstructive sleep apnea (OSA) and cardiac as well as coronary impairment evaluated using imaging modalities. Finding of this study will provide more robust evidence regarding OSA-induced cardiovascular damage.

METHODS

We systematically searched through PubMed, EMBASE, and Cochrane library databases for relevant literatures on the association between OSA and cardiovascular damage evaluated using imaging modalities, and manually searched the references of selected articles for additional relevant articles. For each clinical parameter relevant to the meta-analysis, we first evaluated the methodological heterogeneity of the relevant studies and thereafter pooled the data together using fixed effect or random effect model. The difference in the relevant indices of cardiovascular damage between OSA patients and controls was evaluated using the standardized mean difference.

RESULTS

Of the 82 articles included in the final systematic analysis, 20 studies explored the association between OSA and coronary atherosclerosis. OSA patients had higher rate of coronary atherosclerosis assessed by coronary artery calcification score and plaque volume. Moreover, the severity of OSA and coronary atherosclerosis displayed a positive correlation. The rest of the studies (n = 62) evaluated cardiac alterations in OSA patients. According to the inclusion and exclusion criteria, 46 studies yielding 3082 OSA patients and 1774 controls were pooled for the meta-analysis. For left cardiac structure and function, OSA patients exhibited significantly wider left atrial diameter; higher left atrium volume index; wider left ventricular end-systolic diameter, left ventricular end-diastolic diameter, and left ventricular mass; higher left ventricular mass index; wider interventricular septum diameter and posterior wall diameter; and higher left ventricular myocardial performance index (all p < 0.05). In addition, compared with controls, left ventricular ejection fraction was significantly decreased in OSA patients (p = 0.001). For right cardiac structure and function, OSA patients displayed a significant increase in right ventricular diameter and right ventricular myocardial performance index (both p < 0.001). Finally, compared with controls, OSA patients displayed significant decrease in tricuspid annular plane systolic excursion and RV fractional area change (p = 0.001).

CONCLUSION

Overall, this systematic review and meta-analysis provides imaging evidence in support that OSA patients are at a higher risk of developing coronary atherosclerosis and display cardiac remodeling and dysfunction.

Association Between OSA and Quantitative Atherosclerotic Plaque Burden: A Coronary CT Angiography Study

BACKGROUND

Limited evidence is available regarding the association between OSA and coronary plaque assessed by using quantitative coronary CT angiography.

RESEARCH QUESTION

Are there any associations between OSA severity-related indexes and the presence and burden of coronary plaque?

STUDY DESIGN AND METHODS

Cross-sectional data from 692 patients who underwent sleep monitoring and coronary CT angiography were used for this study. Of these patients, 120 (17.3%) underwent polysomnography, and 572 (82.7%) underwent respiratory polygraphy. Multivariable logistic and linear regression analyses were used to investigate the associations of OSA severity-related indexes with the presence, volume, and composition of plaque.

RESULTS

In multivariable analyses, patients with moderate to severe OSA were more likely to have coronary plaques (P = .037), and plaques were more likely to contain a noncalcified plaque (NCP) component (P = .032) and a low-density NCP (LD NCP) component (P = .030). Furthermore, the apnea-hypopnea index and oxygen desaturation index as continuous variables were both associated with the presence of plaque, NCP, and LD NCP (all, P < .05). Multivariable linear regression models showed that moderate to severe OSA was associated with NCP volume (β = 50.328; P = .042) and LD NCP volume (β = 15.707; P = .011). Moreover, the apnea-hypopnea index (P = .015), oxygen desaturation index (P = .005), and percentage of nighttime with oxygen saturation < 90% (P = .017) were all significant predictors of LD NCP volume. Compared with those with no or mild OSA, patients with severe OSA had a significantly higher total plaque volume (P = .036), NCP volume (P = .036), and LD NCP volume (P = .013).

INTERPRETATION

OSA was independently associated with the presence and burden of coronary plaque, which suggests an increased risk of coronary events.

CLINICAL TRIAL REGISTRATION

Chinese Clinical Trial Registry; No. ChiCTR-ROC-17011027; http://chictr.org.cn.

An Update on Obstructive Sleep Apnea for Atherosclerosis: Mechanism, Diagnosis, and Treatment

The occurrence and development of atherosclerosis could be influenced by intermittent hypoxia. Obstructive sleep apnea (OSA), characterized by intermittent hypoxia, is world-wide prevalence with increasing morbidity and mortality rates. Researches remain focused on the study of its mechanism and improvement of diagnosis and treatment. However, the underlying mechanism is complex, and the best practice for OSA diagnosis and treatment considering atherosclerosis and related cardiovascular diseases is still debatable. In this review, we provided an update on research in OSA in the last 5 years with regard to atherosclerosis. The processes of inflammation, oxidative stress, autonomic nervous system activation, vascular dysfunction, platelet activation, metabolite dysfunction, small molecule RNA regulation, and the cardioprotective occurrence was discussed. Additionally, improved diagnosis such as, the utilized of portable device, and treatment especially with inconsistent results in continuous positive airway pressure and mandibular advancement devices were illustrated in detail. Therefore, further fundamental and clinical research should be carried out for a better understanding the deep interaction between OSA and atherosclerosis, as well as the suggestion of newer diagnostic and treatment options.

Analysis of Circulating Microvesicles Levels and Effects of Associated Factors in Elderly Patients With Obstructive Sleep Apnea

Background: The incidence of obstructive sleep apnea (OSA) in the elderly is high, and the disorder is associated with a variety of chronic diseases. Microvesicles (MVs) are extracellular vesicles secreted by various cells during stimulation or apoptosis that play an important role in the pathogenesis of OSA. However, concentrations of circulating MVs in elderly patients with OSA remain unclear.

Methods: Patients aged >60 years old were recruited and underwent polysomnography. Circulating plasma MV concentrations, including annexin V⁺MVs, endothelial MVs (EMVs), platelet MVs (PMVs), and leukocyte MVs (LMVs) levels, were measured using a flow cytometer with different labeling methods. Potential factors affecting the concentration of circulating MVs in elderly patients with OSA were determined via Spearman's correlation and multiple linear regression analysis.

Results: Levels of circulating MVs, including both single- (annexin V⁺MVs, CD144⁺EMVs, CD41a⁺PMVs, and CD45⁺LMVs) and dual-labeled MVs (annexin V⁺CD144⁺EMVs), were elevated in elderly patients with OSA. Circulating MVs were positively correlated with OSA severity (AHI, ODI, and SPO_2min). To some extent, obesity affected the MV concentrations in elderly patients with OSA. In addition, age and comorbidities may be associated with MV levels, but the correlations between the MV levels and age or comorbidities were not significant.

Conclusion: Concentrations of circulating MVs in elderly patients with OSA are associated with the labeling method used, OSA severity, and obesity. The effects of age and comorbidities on circulating MV levels require further verification using a larger sample size.

miR-3574 ameliorates intermittent hypoxia-induced cardiomyocyte injury through inhibiting Axin1

Objective: miRNAs play critical roles in the regulation of many cardiovascular diseases. However, its role and potential mechanism in cardiac injury caused by obstructive sleep apnea (OSA) remain poorly elucidated. In the present study, we aimed to investigate the effects of miR-3574 on cardiomyocyte injury under intermittent hypoxia (IH).

Results: We confirmed that IH inhibited cell viability, induced cell apoptosis and suppressed miR-3574 expression in the H9c2. miR-3574 overexpression could ameliorate the effects of IH on the cell viability and cell apoptosis in the H9c2. Axin1 was a target gene of miR-3574, and miR-3574 overexpression reduced the expression of Axin1. miR-3574 could inhibit the IH-induced cardiomyocyte injury via downregulating Axin1. However, Axin1 could partially reverse these effects of miR-3574.

Conclusion: Our study first reveals that miR-3574 could alleviate IH-induced cardiomyocyte injury by targeting Axin1, which may function as a novel and promising therapy target for OSA-associated cardiovascular diseases.

Methods: H9c2 were exposed to IH condition. CCK-8 assay was applied to determine cell viability of H9c2. qRT-PCR was conducted to measure the expression level of mRNA and miRNA. Western blot assay was then performed to detect the protein levels. Finally, we used dual-luciferase reporter assay identify the potential target of miR-3574.

Obstructive sleep apnea increases heart rhythm disorders and worsens subsequent outcomes in elderly patients with subacute myocardial infarction

OBJECTIVE

Obstructive sleep apnea (OSA) is a potential cardiovascular risk. We aimed to investigate the association of OSA with heart rhythm disorders and prognosis in elderly patients with new-onset acute myocardial infarction (AMI).

METHODS

We prospectively enrolled 252 AMI elderly patients (mean age, 68.5 ± 6.9 years) who were undergoing revascularization and completed a sleep study during their hospitalization. All subjects were categorized into non-OSA (apnea–hypopnea index (AHI) < 15, n = 130) and OSA (AHI ≥ 15, n = 122) groups based on the AHI. The changes in the autonomic nervous system, incidence of arrhythmia during nocturnal sleep, and major adverse cardiovascular and cerebrovascular events (MACCEs) were compared between the groups.

RESULTS

The mean AHI value in all AMI patients was 22.8 ± 10.9. OSA patients showed higher levels of body mass index and peak high-sensitivity C-reactive protein and lower levels of minimum nocturnal oxygen saturation (MinSaO₂), as well as greater proportion of multivessel coronary artery disease (all P < 0.05). The OSA group also showed significant increases in heart rate variability and heart rate turbulence onset (both P < 0.05) and higher incidence of arrhythmia (including sinus, atrial, and ventricular in origin). At a median follow-up of 6 months (mean 0.8–1.6 years), OSA (AHI ≥ 15) combined with hypoxia (MinSaO ₂ ≤ 80%) was independently associated with the incidence of MACCEs (hazard ratio [HR]: 4.536; 95% confidence interval [CI]: 1.461−14.084,P = 0.009) after adjusting for traditional risk factors.

CONCLUSIONS

OSA and OSA-induced hypoxia may correlate with the severity of myocardial infarction, increase the occurrence of heart rhythm disorders in elderly subacute MI patients, and worsen their short-term poor outcomes.

[Correlation between transient receptor potential canonical channel with heart and kidney injure of rat model of obstructive sleep apnea hypopnea syndrome]

OBJECTIVE

To investigate the expression of transient receptor potential canonical channels (TRPCs) in the heart and kidney of rat model of obstructive sleep apnea hypopnea syndrome (OSAHS).

METHODS

Eighteen male SD rats were randomly assigned to intermittent hypoxia (IH) group (n=9 ) and control group (n=9). In IH group, rats were placed in a chamber and exposed to intermittent hypoxia for 8h (10AM-6PM) daily. The expression of TRPC-related mRNA and protein in the heart and kidney tissue were detected by qRT-PCR and Western blotting, respectively.

RESULTS

The mRNA expressions of TRPC3/TRPC4/TRPC5 in heart tissues of IH group were increased significantly compared with the control group (all P>0.05); while there were no significant differences in the mRNA expressions of TRPC1/TRPC3/TRPC4/TRPC5/TRPC6/TRPC7 in kidney tissue between two groups (all P<0.05). The mRNA expressions of TRPC4, TRPC5 and TRPC6 in kidney tissues of IH group were lower than that in heart tissues (all P<0.05). The mRNA expression of TRPC7 in kidney tissues of control group was significantly higher than that in heart tissues (P<0.05). The expression of TRPC5 protein in heart tissues of IH group was significantly higher than that in the control group (P<0.05); while there was no significant differences in the expression of TRPC5/TRPC6/TRPC7 protein in kidney tissue between two groups (all P>0.05).

CONCLUSIONS

The IH rat model shows that TRPC5 channel is likely to be involved in the OSAHS induced pathophysiological changes in the myocardium and may become a target to prevent OSAHS related cardiac damage.