Sleep apnea and the impact on cardiovascular risk in patients with Marfan syndrome

High-Fat Diet Has a Protective Sex-Dependent Effect on Aortic Aneurysm Severity in a Marfan Syndrome Mouse Model

BACKGROUND

Marfan syndrome (MFS) is a genetic disorder caused by mutations in fibrillin-1 and is characterized by thoracic aortic aneurysms and other complications. Previous studies revealed sexual dimorphisms in formation of aortic aneurysm in patients with MFS. The current study aimed to investigate the combined role of a high-fat diet (HFD) and biological sex in aortic disease using the mgR/mgR MFS mouse model.

METHODS

Male and female mgR/mgR mice, as well as wild-type (WT) littermate mice, were fed a control diet (CD [10% fat]) or HFD (60% fat) from 4 to 12 weeks of age. Key aortic disease parameters analyzed included the diameter of the aortic wall; elastic fibre fragmentation; proteoglycan content; mRNA levels of Mmp12, Col1a1, Col3a1, and Fbn1; and fibrillin-1 deposition in the aortic wall.

RESULTS

HFD-fed female mgR/mgR mice had significantly reduced aortic diameters (35%), elastic fibre fragmentation (56%), pathologically enhanced proteoglycans (45%), and expression of Mmp12 (64%), Col1a1 (41%), and Col3a1 (43%) compared with male mgR/mgR mice on HFD. Fibrillin-1 deposition and Fbn1 mRNA levels were unaffected. The data reveal a protective effect of HFD in female mice. In contrast, CD did not exert any protective effects.

CONCLUSIONS

This study demonstrates a specific sexual dimorphism in MFS mice, with HFD exerting an explicit protective effect on severity of aortic disease in female mice. These preclinical data may be useful for developing nutritional recommendations for individuals with MFS in the longer term.

Sleep apnea predicts cardiovascular death in patients with Marfan syndrome: a cohort study

Background

Surgical replacement of the aortic root is the only intervention that can prevent aortic dissection and cardiovascular death in Marfan syndrome (MFS). However, in some individuals, MFS also causes sleep apnea. If sleep apnea predicts cardiovascular death, a new target for predictive, preventive, and personalized medicine (PPPM) may emerge for those individuals with MFS who have sleep apnea.

Methods

This is an investigator-initiated study with long-term follow-up data of 105 individuals with MFS. All individuals were screened for sleep apnea regardless of symptoms. Cardiovascular death served as a primary endpoint, and aortic events as a secondary outcome.

Results

Sleep apnea with an apnea–hypopnea index (AHI) > 5/h was observed in 21.0% (22/105) with mild sleep apnea in 13% (14/105) and moderate to severe sleep apnea in 7.6% (8/105). After a median follow-up of 7.76 years (interquartile range: 6.84, 8.41), 10% (10/105) had died, with cardiovascular cause of death in 80% (8/10). After adjusting for age and body mass index (BMI), the AHI score emerged as an independent risk factor for cardiovascular death (hazard ratio 1.712, 95% confidence interval [1.061–2.761], p = 0.0276). The secondary outcome of aortic events occurred in 33% (35/105). There was no effect of the AHI score on aortic events after adjusting for age and BMI (hazard ratio 0.965, 95% confidence interval [0.617–1.509]), possibly due to a high number of patients with prior aortic surgery.

Interpretation

Sleep apnea is emerging as an independent predictor of cardiovascular death in MFS. It seems mandatory to screen all individuals with MFS for sleep apnea and to include these individuals, with both MFS and sleep apnea, in further studies to evaluate the impact of preventive measures with regard to cardiovascular death.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13167-022-00291-4.

Assessment of pleural pressure during sleep in Marfan syndrome

STUDY OBJECTIVES

Patients with Marfan syndrome (MFS) have a high risk for aortic aneurysms. They are also susceptible to sleep-disordered breathing that may expose them to highly negative intrathoracic pressures known to increase aortic transmural pressure which may accelerate aortic dilatation. Our objective was to quantify overnight intrathoracic pressure changes during sleep in snoring patients with MFS, and the therapeutic effect of continuous positive airway pressure (CPAP).

METHODS

We used a questionnaire to identify self-reported snoring patients with MFS. In these patients, we monitored intrathoracic pressure using esophageal pressure (Pes) during overnight baseline and CPAP sleep studies. We defined a peak inspiratory Pes (Pes_peak-insp) < - 5 cmH₂O as greater than normal, and examined the distribution of Pes_peak-insp during baseline and CPAP studies.

RESULTS

In our sample of 23 MFS snorers, we found that 70% of sleep breaths exhibited Pes_peak-insp < -5 cmH₂O, with apneas/hypopneas accounting for only 12%, suggesting prevalent stable flow-limited breathing and snoring. In a subset (n=12) with Pes monitoring during CPAP night, CPAP lowered the mean proportion of breaths with Pes_peak-insp < -5 cmH₂O from 83.7±14.9% to 3.6±3.0% (p<0.001). In addition, contemporaneous aortic root diameter was associated with the mean Pes_peak-insp during IFL and apneas/hypopneas (β= -0.05, r=0.675, p=0.033).

CONCLUSIONS

The sleep state in MFS revealed prolonged exposure to exaggerated negative inspiratory Pes, which was reversible with CPAP. Since negative intrathoracic pressure can contribute to thoracic aortic stress and aortic dilatation, snoring may be a reversible risk factor for progression of aortic pathology in MFS.

Respiratory manifestations of Marfan syndrome: a narrative review

Objective

The prevalence of Marfan syndrome (MFS) is estimated to be 1 in 10,000 to 15,000 individuals, but the phenotype of MFS may not be apparent and hence its diagnosis may not be considered by clinicians. Furthermore, the effects of MFS on the lungs and breathing are underrecognized despite the high morbidity that can occur. The objective of this Narrative Review is to delineate the molecular consequences of a defective fibrillin-1 protein and the skeletal and lung abnormalities in MFS that may contribute to respiratory compromise. It is important for clinicians to be cognizant of these MFS-associated respiratory conditions, and a contemporaneous review is needed.

Background

MFS is an autosomal dominant, connective tissue disorder caused by mutations in the FIBRILLIN-1 (FBN1) gene, resulting in abnormal elastic fibers as well as increased tissue availability of transforming growth factor-beta (TGFβ), both of which lead to the protean clinical abnormalities. While these clinical characteristics are most often recognized in the cardiovascular, skeletal, and ocular systems, MFS may also cause significant impairment on the lungs and breathing.

Methods

We searched PubMed for the key words of “Marfan syndrome,” “pectus excavatum,” and “scoliosis” with that of “lung disease,” “breathing”, or “respiratory disease.” The bibliographies of identified articles were further searched for relevant articles not previously identified. Each relevant article was reviewed by one or more of the authors and a narrative review was composed.

Conclusions

Though the classic manifestations of MFS are cardiovascular, skeletal, and ocular, FBN1 gene mutation can induce a variety of effects on the respiratory system, inducing substantial morbidity and potentially increased mortality. These respiratory effects may include chest wall and spinal deformities, emphysema, pneumothorax, sleep apnea, and potentially increased incidence of asthma, bronchiectasis, and interstitial lung disease. Further research into approaches to prevent respiratory complications is needed, but improved recognition of the respiratory complications of MFS is necessary before this research is likely to occur.

Sleep Bruxism and SDB in Albanian Growing Subjects: A Cross-Sectional Study

Background: The aim of this study was to evaluate a possible correlation between sleep bruxism and risk factors of developing obstructive sleep apnea syndrome (OSAS) in a sample of growing subjects and to assess parental awareness about sleep bruxism in their children. Methods: The sample was composed of 310 subjects (173 females and 137 males), with a mean age of 8.9 years, attending "Ndre Mjeda" school of Tirana (Albania). All parents of the children participating in the study were asked to fill in a questionnaire manually or via a digital version. The questionnaire was composed of three sections: personal data, sleep quality data, and OSAS risk factors, and it was filled out by both parents. Results: Of our samples, 41.3% presented with bruxism, and 16.5% of the parents ground their teeth. Oral breathing was reported in 11.9% of the subjects, and among these, 40% of the subjects were affected by bruxism (p > 0.05). Of the subjects, 18.7% snore overnight. Comparing it with sleep bruxism, the two phenomena are often related (p = 0.00). Conclusions: Heredity, night-sweating, nycturia, oral breathing, and snoring seem to have a significant correlation with bruxism.

Spontaneous Right Ventricular Pseudoaneurysms and Increased Arrhythmogenicity in a Mouse Model of Marfan Syndrome

Patients with Marfan syndrome (MFS), a connective tissue disorder caused by pathogenic variants in the gene encoding the extracellular matrix protein fibrillin-1, have an increased prevalence of primary cardiomyopathy, arrhythmias, and sudden cardiac death. We have performed an in-depth in vivo and ex vivo study of the cardiac phenotype of Fbn1mgR/mgR mice, an established mouse model of MFS with a severely reduced expression of fibrillin-1. Using ultrasound measurements, we confirmed the presence of aortic dilatation and observed cardiac diastolic dysfunction in male Fbn1mgR/mgR mice. Upon post-mortem examination, we discovered that the mutant mice consistently presented myocardial lesions at the level of the right ventricular free wall, which we characterized as spontaneous pseudoaneurysms. Histological investigation demonstrated a decrease in myocardial compaction in the MFS mouse model. Furthermore, continuous 24 h electrocardiographic analysis showed a decreased heart rate variability and an increased prevalence of extrasystolic arrhythmic events in Fbn1mgR/mgR mice compared to wild-type littermates. Taken together, in this paper we document a previously unreported cardiac phenotype in the Fbn1mgR/mgR MFS mouse model and provide a detailed characterization of the cardiac dysfunction and rhythm disorders which are caused by fibrillin-1 deficiency. These findings highlight the wide spectrum of cardiac manifestations of MFS, which might have implications for patient care.

Sleep apnea and the impact on cardiovascular risk in patients with Marfan syndrome

Background

Marfan syndrome (MFS) is an inherited connective tissue disorder characterized by ectopia lentis, aortic root dilation and dissection and specific skeletal features. Obstructive sleep apnea (OSA) in MFS has been described earlier but the prevalence and its relation with the cardiovascular risk is still controversial. This study aimed to further investigate these aspects.

Methods

In this prospective longitudinal study, we performed an attended polysomnography in 40 MFS patients (60% women, 37 ± 12.8 years) and evaluated several cardiovascular parameters through echocardiography, resting electrocardiogram, 24 hr‐Holter monitoring and serum NT‐ProBNP measurements.

Results

We found that OSA was present in 42.5% of the patients and that higher body mass index was the most important factor associated with the presence of OSA. We observed that overweight was present in 27.5% of the patients in the whole cohort and in 55.6% if >40 years. Furthermore, when evaluating the impact of OSA on the cardiovascular system, we observed that patients with OSA tended to have higher systolic blood pressure, larger distal aortic diameters and a higher prevalence of ventricular arrhythmia. These differences were, however, not significant after adjusting for confounders.

Conclusions

Our study shows a high prevalence of OSA and a high prevalence of overweight in MFS patients. We found some trends between OSA and cardiovascular features but we could not establish a solid association. Our study, however might be underpowered, and a multicenter collaborative study could be very useful to answer some important open questions.