Designing an experimental method for assessing biocompatibility of circuit coatings using biomarkers for platelet activation during cardiopulmonary bypass.

INTRODUCTION: Cardiopulmonary bypass is an essential component of cardiothoracic surgeries. However, significant complications such as systemic inflammatory response syndrome (SIRS) resulting from cardiopulmonary bypass (CPB) are a common occurrence due to contact between circulating blood and foreign surfaces that leads to platelet activation. It is suggested that different available CPB circuit coatings can potentially reduce platelet activation. However, there have been no published evidence-based reports confirming these claims. In addition, there is no well-established protocol for studying platelet activation biomarkers during CPB in vitro in a laboratory setting. METHODS: CPB was simulated in the laboratory using bovine blood in two different types of coated CPB circuits: Trillium® Biosurface by Medtronic, and XcoatingTM Surface by Terumo. Fresh bovine blood samples were collected and circulated through the CPB circuit following the standard protocol used in the operation rooms. Blood samples were then collected at 5 min, 30 min, and 55 min during the circulation. Blood plasmas were separated and subjected to enzyme-linked immunosorbent assay to measure most established platelet activation markers P-selectin, Platelet Factor 4 (PF4), Glycoprotein IIb/IIIa (GPIIb/IIIa), and ß-thromboglobulin (ß-TG) at different time points. RESULTS: The biomarker values at 30 min and 55 min were compared to the base values at 5 min for each type of CPB circuit. The results of the means from all measured biomarkers showed data measurements that indicated no significant variability within each coating. All collected data points fell within ±2 SD of the means, which was considered acceptable variations across technical replicates.  Conclusion: In this study, we were able to establish an in vitro protocol in the laboratory setting that is precise and reliable with minimum intra-variability. This established protocol will allow for future studies in which different coated CPB circuits can be compared for their effectiveness in blocking platelet activation during the CPB.

Impact of maternal dietary folic acid or choline dietary deficiencies on vascular function in young and middle-aged female mouse offspring after ischemic stroke.

Adequate maternal dietary levels of one-carbon metabolites, such as folic acid and choline, play an important role in the closure of the neural tube in utero; however, the impact of deficiencies in one-carbon (1C) metabolism on offspring neurological function after birth remain undefined. Stroke is one of the leading causes of death and disability globally. The aim of our study was to determine the impact of maternal 1C nutritional deficiencies on cerebral and peripheral blood flow after ischemic stroke in adult female offspring. In this study, female mice were placed on either control (CD)-, folic acid (FADD)-, or choline (ChDD)-deficient diets before pregnancy. Female offspring were weaned onto a CD for the duration of the study. Ischemic stroke was induced in offspring and after 6 wk cerebral and peripheral blood flow velocity was measured using ultrasound imaging. Our data showed that 11.5-mo-old female offspring from ChDD mothers had reduced blood flow in the posterior cerebral artery compared with controls. In peripheral blood flow velocity measurements, we report an aging effect. These results emphasize the importance of maternal 1C diet in early life neuro-programming on long-term vasculature health.NEW & NOTEWORTHY We demonstrate that a maternal dietary deficiency in one-carbon (1C) metabolites result in reduced cerebral blood flow in adult female offspring after ischemic stroke, but the long-term effects are not present. This result points to the key role of the maternal diet in early life neuroprogramming, while emphasizing its effects on both fetal development and long-term cerebrovascular health.

Can 10 000 Healthy Steps a Day Slow Aortic Root Dilation in Pediatric Patients With Marfan Syndrome?

Background Stiffer aortas are associated with a faster rate of aortic root (AoR) dilation and higher risk of aortic dissection in patients with Marfan syndrome. We have previously shown that mild aerobic exercise reduces aortic stiffness and rate of AoR dilation in a Marfan mouse model. In this study, we investigated if these results could be translated to pediatric patients with Marfan syndrome. Methods and Results We enrolled 24 patients with Marfan syndrome aged 8 to 19 years to participate in a 6-month physical activity intervention, excluding those with ventricular dysfunction or prior history of aortic surgery. We instructed patients to take 10 000 steps per day, tracked by an activity tracker. At baseline and 6 months, we measured AoR dimension, arterial stiffness, endothelial function, physical activity indices, inflammatory biomarkers, and coping scores. Controls consisted of 15 age-matched patients with Marfan syndrome. Twenty-four patients with Marfan syndrome (median age, 14.4 years [interquartile range {IQR}, 12.2-16.8], 14 male patients) were enrolled. Baseline assessment demonstrated that the majority of these patients were sedentary and had abnormal arterial health. Twenty-two patients completed the intervention and took an average of 7709±2177 steps per day (median, 7627 [IQR, 6344-9671]). Patients wore their Garmin trackers at a median of 92.8% (IQR, 84%-97%) of their intervention days. AoR Z score in the intervention group had a significantly lower rate of change per year compared with the controls (rate of change, -0.24 versus +0.008; P=0.01). Conclusions In this clinical intervention in pediatric patients with Marfan syndrome, we demonstrated that a simple physical activity intervention was feasible in this population and has the potential to decrease the AoR dilation rate. REGISTRATION URL: https://www.clinicaltrials.gov; Unique identifier: NCT03567460.

Case report: Lingering post-concussive symptoms in a pediatric patient with presumed Ehlers-Danlos syndrome.

Background: Connective tissue disorders such as Ehlers-Danlos Syndrome (EDS) can affect collagen and elastin content and structure, including weakening of tissues and vasculature, thus contributing to multiple systemic manifestations. Prior research has successfully focused on peripheral life-threatening manifestations resulting in increased life expectancy, yet clinical observations have warranted investigation of neurological vulnerability, where little is known. Compromised brain tissues and cerebrovasculature could leave these patients vulnerable to mild traumatic brain injury (TBI), with increased severity and duration of post-concussive symptoms and delayed recovery. Clinical reports in adults indicate that higher severity of symptoms after a mild TBI, such as a concussion, can unmask connective tissues disorders leading toward diagnosis. This clinical case report is an example of a pediatric patient with presumed Ehlers-Danlos syndrome who demonstrates increased vulnerability to mild TBI/concussion. Patient: A pediatric female patient presents with unexplained lingering post-concussive symptoms, including trouble sleeping, nausea, frontal headaches, dizziness, visual changes, fatigue, and left-sided weakness more than 6 months post-mild concussion. Patient history of hypermobility, joint derangement, soft tissue mobility, and bruising suggests a potential diagnosis of Ehlers-Danlos syndrome, which may explain symptom severity and length of recovery. Discussion: This case is the first documented instance of increased vulnerability to TBI in a pediatric patient with presumed Ehlers-Danlos syndrome. It highlights the need for awareness and prevention of injury in this vulnerable patient population, suggests more targeted therapeutic intervention for recovery, and demonstrates the need for preclinical research evaluating the influence of genetic mutations associated with connective tissue disorders on the central nervous system.

Measurement of Endothelium-dependent Vasorelaxation in the Mouse Thoracic Aorta using Tensometric Small Volume Chamber Myography.

Small volume chamber tensometric myography is a commonly used technique to evaluate the vascular contractility of small and large blood vessels in laboratory animals and small arteries isolated from human tissue. The technique allows researchers to maintain isolated blood vessels in a tightly controlled and standardized (near-physiological) setting, with the option of adjusting to various environmental factors, while challenging the isolated vessels with different pharmacological agents that can induce vasoconstriction or vasodilation. The myograph chamber also provides a platform to measure vascular reactivity in response to various hormones, inhibitors, and agonists that may impact the function of smooth muscle and endothelial layers separately or simultaneously. The blood vessel wall is a complex structure consisting of three different layers: the intima (endothelial layer), media (smooth muscle and elastin fibers), and adventitia (collagen and other connective tissue). To gain a clear understanding of the functional properties of each layer, it is critical to have access to an experimental platform and system that would allow for a combinational approach to study all three layers simultaneously. Such an approach demands access to a semi-physiological condition that would mimic the in vivo environment in an ex vivo setting. Small volume chamber tensometric myography has provided an ideal environment to evaluate the impact of environmental cues, experimental variables, or pharmacological agonists and antagonists on vascular properties. For many years, scientists have used the tensometric myograph technique to measure endothelial function and smooth muscle contractility in response to different agents. In this report, a small volume chamber tensometric myograph system is used to measure endothelial function in the isolated mouse aorta. This report focuses on how small volume chamber tensometric myography can be used to evaluate the functional integrity of the endothelium in small segments of a large artery such as the thoracic aorta.

Swallowing and quality of life in individuals with Marfan syndrome: a cross-sectional study.

PURPOSE: Marfan syndrome (MFS) is a connective tissue disorder that affects skeletal, ocular, pulmonary, cardiovascular, and central nervous systems. Symptoms may lead to diminished quality of life (QoL) in individuals with MFS compared with healthy individuals. Currently, there is little evidence regarding the impact of MFS on swallowing and QoL. This study examined perceptions of swallowing difficulties and QoL among persons with MFS. METHOD: A total of 356 participants (1% response rate) with a self-reported diagnosis of MFS provided medication regime and completed a Quality-of-Life Index and a modified version of the SWAL-QOL used to assess 8 QOL concepts related to swallowing: burden, duration, desire, food choice, fear, mental health, social concerns, and fatigue. RESULTS: Dysphagia symptoms were reported by 62% (N = 356) of the participants. Analyses assessing correlations between responses to SWAL-QOL questions, QoL scores, and reported medications were conducted. Further, responses on the SWAL-QOL predicted QoL satisfaction, even after controlling for medications. Findings revealed that greater swallowing difficulty affects QoL satisfaction and overall QoL, but not QoL importance. Further, specific medications were associated with differences in swallowing difficulty as well as QoL satisfaction. CONCLUSIONS: The findings of the current study suggest that individuals with MFS may experience specific swallowing difficulties which impact QoL. Specific classes of drugs may also be associated with reported swallowing QoL and QoL satisfaction in MFS. These findings have implications for clinicians who work with individuals with MFS.

Pleiotropic activation of endothelial function by angiotensin II receptor blockers is crucial to their protective anti-vascular remodeling effects.

There are no therapeutics that directly enhance chronic endothelial nitric oxide (NO) release, which is typically associated with vascular homeostasis. In contrast, angiotensin II (AngII) receptor type 1 (AT1R) blockers (ARBs) can attenuate AngII-mediated oxidative stress, which often leads to increased endothelial NO bioavailability. Herein, we investigate the potential presence of direct, AngII/AT1R-independent ARB class effects on endothelial NO release and how this may result in enhanced aortic wall homeostasis and endothelial NO-specific transcriptome changes. Treatment of mice with four different ARBs induced sustained, long-term inhibition of vascular contractility by up to 82% at 16 weeks and 63% at 2 weeks, an effect reversed by L-NAME and absent in endothelial NO synthase (eNOS) KO mice or angiotensin converting enzyme inhibitor captopril-treated animals. In absence of AngII or in tissues with blunted AT1R expression or incubated with an AT2R blocker, telmisartan reduced vascular tone, supporting AngII/AT1R-independent pleiotropism. Finally, telmisartan was able to inhibit aging- and Marfan syndrome (MFS)-associated aortic root widening in NO-sensitive, BP-independent fashions, and correct aberrant TGF-ß signaling. RNAseq analyses of aortic tissues identified early eNOS-specific transcriptome reprogramming of the aortic wall in response to telmisartan. This study suggests that ARBs are capable of major class effects on vasodilatory NO release in fashions that may not involve blockade of the AngII/AT1R pathway. Broader prophylactic use of ARBs along with identification of non-AngII/AT1R pathways activated by telmisartan should be investigated.

Voice Symptoms and Quality of Life in Individuals With Marfan Syndrome: A Cross-Sectional Study.

PURPOSE: Marfan Syndrome (MFS) is a connective tissue disorder that affects skeletal, ocular, pulmonary, cardiovascular, and central nervous systems. Symptoms may lead to diminished quality of life (QoL) in individuals with MFS compared with healthy individuals. Currently, there is little evidence regarding the impact of MFS on voicing and QoL. This study examined perceptions of voicing difficulties and QoL among persons with MFS. METHOD: A total of 356 participants with a self-reported diagnosis of MFS completed the Quality-of-Life Index (QLI) and voice handicap index-10 (VHI-10) and provided medication regime. RESULTS: Some degree of voice handicap was reported by a majority of participants. Analyses assessing correlations between responses to the VHI-10, QLI scores, and reported medications were conducted. Specific medications and responses on the VHI-10 were significantly associated with QLI scores. Multiple regression analyses revealed that a summed VHI-10 score was the strongest predictor of QLI satisfaction, QLI importance, and overall QLI. CONCLUSIONS: The findings of the current study suggest that individuals with MFS may experience self-perceived phonatory dysfunction which impact QoL. Specific classes of drugs may also be associated with reported voice handicap and QoL satisfaction in MFS. These findings have implications for physicians and clinicians who work with individuals with MFS.

Aortic Dimensions, Biophysical Properties, and Plasma Biomarkers in Children and Adults with Marfan or Loeys-Dietz Syndrome.

BACKGROUND: Aortic dilation, stiffening, and dissection are common and potentially lethal complications of Marfan syndrome (MFS) and Loeys-Dietz syndrome (LDS), which involve abnormal transforming growth factor beta (TGF-ß) signalling. The relation of aortic dimensions, stiffness, and biomarker levels is unknown. The objective of this study was to measure aortic dimensions, stiffness, TGF-ß and matrix metalloproteinase (MMP) levels, and endothelial function in patients with MFS, and to compare TGF-ß levels in patients with MFS receiving different therapeutic regimens. METHODS: This was a cohort study of 40 MFS and 4 LDS patients and 87 control participants. Aortic dimension and stiffness indexes, including pulse wave velocity (PWV), were measured using echocardiography and Doppler. Total and free TGF-ß and MMP blood levels were measured using Quantikine (R&D Systems, Inc, Minneapolis, MN) and Quanterix (Billerica, MA) kits. Endothelial function was measured using brachial artery flow-mediated dilation. RESULTS: PWV was increased in patients with MFS. There were increased MMP-2 levels in those with MFS but no increase in free or total TGF-ß or MMP-9 levels compared with control participants. There was no difference in TGF-ß levels between MFS patients receiving no medications, angiotensin receptor blockers, and ß-blockers. PWV correlated most strongly with age. Endothelial function showed premature gradual decline in patients with MFS. CONCLUSIONS: Despite the increased PWV, monitoring aortic stiffness or TGF-ß levels would not be helpful in patients with MFS. TGF-ß levels were not increased and the increased MMP-2 levels suggest consideration of a different therapeutic target.

CONTEXTE: La dilatation, la rigidification et la dissection de l'aorte sont des complications fréquentes et parfois mortelles du syndrome de Marfan (SM) et du syndrome de Loeys-Dietz (SLD), qui sont tous deux dûs à une anomalie de la voie de signalisation du facteur de croissance transformant bêta (TGF-ß). On ne connaît pas la relation entre les dimensions et la rigidité de l'aorte et la présence de biomarqueurs. Notre étude visait à mesurer les dimensions et la rigidité de l'aorte, les taux de TGF-ß et de métalloprotéases matricielles (MMP) et la fonction endothéliale chez des patients atteints du SM, et à les comparer aux taux de TGF-ß observés chez des patients également atteints de SM, mais recevant un autre traitement. MÉTHODOLOGIE: Il s'agissait d'une étude de cohorte menée auprès de 40 patients atteints du SM et de quatre patients atteints du SLD, ainsi que de 87 témoins. Les indices des dimensions et de la rigidité aortiques, y compris la vitesse d'onde de pouls (VOP), ont été mesurés par échocardiographie et par échographie Doppler. Les taux sanguins de TGF-ß et de MMP totaux et libres ont été mesurés à l'aide de trousses Quantikine (R&D Systems, Inc, Minneapolis, MN) et Quanterix (Billerica, MA). La fonction endothéliale a été mesurée par dilatation liée au flux dans l'artère brachiale. RÉSULTATS: La VOP était plus élevée chez les patients atteints du SM. On a aussi observé une hausse des taux de MMP-2 chez les patients atteints de SM, mais aucune augmentation des taux de TGF-ß ou de MMP-9 libres ou totaux comparativement aux témoins. Il n'y avait pas de différence entre les taux de TGF-ß chez les patients atteints de SM ne recevant aucun traitement, ceux qui prenaient un antagoniste des récepteurs de l'angiotensine et ceux qui prenaient un bêtabloquant. La VOP été plus fortement corrélée avec l'âge. La fonction endothéliale a affiché un déclin progressif prématuré chez les patients atteints du SM. CONCLUSIONS: Malgré l'augmentation de la VOP, il ne semble pas utile de surveiller la rigidité aortique ni les taux de TGF-ß en cas de SM. Les taux de TGF-ß n'étaient pas plus élevés chez les patients atteints du SM, et la hausse des taux de MMP-2 indique qu'il conviendrait de choisir une autre cible thérapeutique.

Blood pressure-independent inhibition of Marfan aortic root widening by the angiotensin II receptor blocker valsartan.

Marfan syndrome (MFS) is a genetic disorder that results in accelerated aortic root widening and aneurysm. However, management of MFS patients with blood pressure (BP)-lowering medications, such as angiotensin II (AngII) receptor blocker (ARB) losartan, continues to pose challenges due to their questionable efficacy at attenuating the rate of aortic root widening in patients. Herein we investigate the anti-aortic root widening effects of a sub-BP-lowering dose valsartan, an ARB previously linked to non-BP lowering anti-remodeling effects. Despite absence of BP-lowering effects, valsartan attenuated MFS aortic root widening by 75.9%, which was similar to a hypotensive dose of losartan (79.4%) when assessed by ultrasound echocardiography. Medial thickening, elastic fiber fragmentation, and phospho-ERK signaling were also inhibited to a similar degree with both treatments. Valsartan and losartan decreased vascular contractility ex vivo between 60% and 80%, in a nitric oxide (NO)-sensitive fashion. Valsartan increased acetylcholine (Ach)-induced vessel relaxation and phospho-eNOS levels in the aortic vessel supporting BP-independent activation of protective endothelial function, which is critical to ARB-mediated aortic root stability. This study supports the concept of achieving aortic root stability with valsartan in absence of BP-lowering effects, which may help address efficacy and compliance issues with losartan-based MFS patient management.

Characterization of doxycycline-mediated inhibition of Marfan syndrome-associated aortic dilation by multiphoton microscopy.

Marfan syndrome (MFS) is a connective tissue disorder that results in aortic root widening and aneurysm if unmanaged. We have previously reported doxycycline, a nonselective matrix metalloproteinases (MMPs) inhibitor, to attenuate aortic root widening and improve aortic contractility and elasticity in MFS mice. We were also first to use multiphoton microscopy, a non-invasive and label-free imaging technique, to quantify and link the aortic ultrastructure to possible changes in the skin dermis. Here, we aimed to assess the effects of long-term doxycycline treatment on the aortic ultrastructure and skin dermis of MFS mice through immunohistochemical evaluation and quantification of elastic and collagen content and morphology using multiphoton microscopy. Our results demonstrate a rescue of aortic elastic fiber fragmentation and disorganization accompanied by a decrease in MMP-2 and MMP-9 expression within the aortic wall in doxycycline-treated MFS mice. At 12 months of age, reduced skin dermal thickness was observed in both MFS and control mice, but only dermal thinning in MFS mice was rescued by doxycycline treatment. MMP-2 and MMP-9 expression was reduced in the skin of doxycycline-treated MFS mice. A decrease in dermal thickness was found to be positively associated with increased aortic root elastin disorganization and wall thickness. Our findings confirm the beneficial effects of doxycycline on ultrastructural properties of aortic root as well as on skin elasticity and structural integrity in MFS mice.

A Review of Psychosocial Factors of Marfan Syndrome: Adolescents, Adults, Families, and Providers.

The purpose of this article was to review the current literature on psychosocial implications of Marfan syndrome (MFS) and its impact on adolescents, adults, their families and to provide important considerations for providers. Since the previous reviews in 2015, numerous studies have been published that are included in the current review. This literature review was conducted using PubMed, Medline, PsychINFO, ERIC, Web of Science, and Academic Search Premier databases and only articles that studied psychosocial factors that influence MFS patients as adolescents, adults, family members, or their interactions with providers were included in this review. Of the 522 articles reviewed, 41 were selected based on the inclusion and exclusion criteria. All articles were peer-reviewed. MFS has various implications that can impact one's life; studies have shown that MFS causes a negative impact on an individual's formative years, quality of life, reproductive decision-making, work participation, and satisfaction with life. Clinicians and multidisciplinary teams should be aware of these factors to provide support focusing on coping strategies for the patient and their family.

Beneficial effects of resveratrol and exercise training on cardiac and aortic function and structure in the 3xTg mouse model of Alzheimer's disease.

Background: Studies have indicated an association between Alzheimer's disease (AD) and increased risk of developing cardiovascular complications. Lifestyle modifiable factors, such as exercise and diet, are known to prevent cardio-cerebral disease. Recent studies demonstrate that hearts from early onset triple-transgenic AD mice exhibit pathologies, but it is not clear whether cardiovascular function is altered in this model. Methods: In this study, we measured in vivo cardiovascular function in 7-month-old male 3xTg mice and age-matched wild-type (WT) mice using high-frequency high-resolution ultrasound imaging. Results: Our findings indicated that aortic root measurements and interventricular septal dimensions were similar in 3xTg and wild-type mice. Systolic function, expressed as ejection fraction and fractional shortening, were decreased in 3xTg mice. Late (A) ventricular filling velocities, the early/atrial (E/A) ratio, and mitral valve deceleration time, all indices of diastolic function, were increased in 3xTg mice compared to WT mice. Treadmill exercise training and resveratrol supplementation in the diet for 5 months improved ejection fraction, fractional shortening, and restored diastolic deceleration times. Pulse wave velocity was ~33% higher in 3xTg, and accompanied by a significant increase in elastin fiber fragmentation within the aortic wall, which was associated with decrease in elastin content and fiber length. Aortic wall and adventitia thickness were increased in 3xTg mice compared to the WT group. Exercise training and resveratrol supplementation, or both, improved overall aortic morphology with no change in pulse wave velocity. Conclusion: Taken together, the results indicate that the aberrations in cardiac function and aortic elastin morphology observed in the 3xTg mouse model of AD can be prevented with exercise training and treatment with resveratrol. The benefits of regular exercise training and resveratrol supplementation of heart and aortic structure in the 3xTg mouse support the value of healthy lifestyle factors on cardiovascular health.

Sildenafil Prevents Marfan-Associated Emphysema and Early Pulmonary Artery Dilation in Mice.

Marfan syndrome (MFS) is a connective tissue disorder caused by mutations in fibrillin-1 (Fbn1). Although aortic rupture is the major cause of mortality in MFS, patients also experience pulmonary complications, which are poorly understood. Loss of basal nitric oxide (NO) production and vascular integrity has been implicated in MFS aortic root disease, yet their contribution to lung complications remains unknown. Because of its capacity to potentiate the vasodilatory NO/cyclic guanylate monophosphate signaling pathway, we assessed whether the phosphodiesterase-5 inhibitor, sildenafil (SIL), could attenuate aortic root remodeling and emphysema in a mouse model of MFS. Despite increasing NO-dependent vasodilation, SIL unexpectedly elevated mean arterial blood pressure, failed to inhibit MFS aortic root dilation, and exacerbated elastic fiber fragmentation. In the lung, early pulmonary artery dilation observed in untreated MFS mice was delayed by SIL treatment, and the severe emphysema-like alveolar destruction was prevented. In addition, improvements in select parameters of lung function were documented. Subsequent microarray analyses showed changes to gene signatures involved in the inflammatory response in the MFS lung treated with SIL, without significant down-regulation of connective tissue or transforming growth factor-ß signaling genes. Because phosphodiesterase-5 inhibition leads to improved lung histopathology and function, the effects of SIL against emphysema warrant further investigation in the settings of MFS despite limited efficacy on aortic root remodeling.

In vivo characterization of doxycycline-mediated protection of aortic function and structure in a mouse model of Marfan syndrome-associated aortic aneurysm.

Aortic aneurysm is the most life-threatening complication in Marfan syndrome (MFS) patients. Doxycycline, a nonselective matrix metalloproteinases inhibitor, was reported to improve the contractile function and elastic fiber structure and organization in a Marfan mouse aorta using ex vivo small chamber myography. In this study, we assessed the hypothesis that a long-term treatment with doxycycline would reduce aortic root growth, improve aortic wall elasticity as measured by pulse wave velocity, and improve the ultrastructure of elastic fiber in the mouse model of MFS. In our study, longitudinal measurements of aortic root diameters using high-resolution ultrasound imaging display significantly decreased aortic root diameters and lower pulse wave velocity in doxycycline-treated Marfan mice starting at 6 months as compared to their non-treated MFS counterparts. In addition, at the ultrastructural level, our data show that long-term doxycycline treatment corrects the irregularities of elastic fibers within the aortic wall of Marfan mice to the levels similar to those observed in control subjects. Our findings underscore the key role of matrix metalloproteinases during the progression of aortic aneurysm, and provide new insights into the potential therapeutic value of doxycycline in blocking MFS-associated aortic aneurysm.

Neurofibromin haploinsufficiency results in altered spermatogenesis in a mouse model of neurofibromatosis type 1.

The fertility of men with neurofibromatosis 1 (NF1) is reduced. Despite this observation, gonadal function has not been examined in patients with NF1. In order to assess the role of reduced neurofibromin in the testes, we examined testicular morphology and function in an Nf1+/- mouse model. We found that although Nf1+/- male mice are able to reproduce, they have significantly fewer pups per litter than Nf1+/+ control males. Reduced fertility in Nf1+/- male mice is associated with disorganization of the seminiferous epithelium, with exfoliation of germ cells and immature spermatids into the tubule lumen. Morphometric analysis shows that these alterations are associated with decreased Leydig cell numbers and increased spermatid cell numbers. We hypothesized that hyper-activation of Ras in Nf1+/- males affects ectoplasmic specialization, a Sertoli-spermatid adherens junction involved in spermiation. Consistent with this idea, we found increased expression of phosphorylated ERK, a downstream effector of Ras that has been shown to alter ectoplasmic specialization, in Nf1+/- males in comparison to control Nf1+/+ littermates. These data demonstrate that neurofibromin haploinsufficiency impairs spermatogenesis and fertility in a mouse model of NF1.

Executive function and quality of life in individuals with Marfan syndrome.

PURPOSE: Marfan syndrome (MFS) is a connective tissue disorder that affects skeletal, ocular, pulmonary, cardiovascular, and central nervous systems. Psychological and physiologic symptoms may lead to diminished quality of life (QoL) in individuals with MFS compared with healthy individuals. Currently, there is little evidence regarding the impact of MFS on executive function and QoL. This study examined perceptions of executive function and QoL among persons with MFS. METHOD: A total of 318 participants with MFS completed surveys assessing perceptions of executive function abilities and QoL. Responses to executive function questions were grouped using principle component analysis. Responses to QoL questions were separated into overall QoL, questions dealing with satisfaction of QoL, and importance placed on aspect of QoL. RESULTS: Principle component analysis revealed that executive function difficulties, particularly mental fatigue, associated with MFS symptoms affect QoL satisfaction and total QoL. Interestingly, medication status did not significantly impact QoL, over and above executive function difficulties. CONCLUSIONS: The findings of the current study suggest that individuals with MFS may experience specific executive function difficulties which impact QoL. These findings also have implications for clinicians who work with individuals with MFS.

Inhibition of Marfan Syndrome Aortic Root Dilation by Losartan: Role of Angiotensin II Receptor Type 1-Independent Activation of Endothelial Function.

Marfan syndrome (MFS) is a genetic disorder that frequently leads to aortic root dissection and aneurysm. Despite promising preclinical and pilot clinical data, a recent large-scale study using antihypertensive angiotensin II (AngII) receptor type 1 (ATR1) blocker losartan has failed to meet expectations at preventing MFS-associated aortic root dilation, casting doubts about optimal therapy. To study the deleterious role of normal ATR1 signaling in aortic root widening, we generated MFS mice lacking ATR1a expression in an attempt to preserve protective ATR2 signaling. Despite being hypotensive and resistant to AngII vasopressor effects, MFS/ATR1a-null mice showed unabated aortic root enlargement and remained fully responsive to losartan, confirming that blood pressure lowering is of minor therapeutic value in MFS and that losartan's antiremodeling properties may be ATR1 independent. Having shown that MFS causes endothelial dysfunction and that losartan can activate endothelial function in mice and patients, we found that nitric oxide synthase (NOS) inhibition renders losartan therapeutically inactive, whereas multiple transgenic and pharmacologic models of endothelial NOS activation block aortic root dilation by correcting extracellular signal-regulated kinase signaling. In vitro, losartan can increase endothelial NO release in the absence of AngII and correct MFS NO levels in vivo. Our data suggest that increased protective endothelial function, rather than ATR1 inhibition or blood pressure lowering, might be of therapeutic significance in preventing aortic root disease in MFS.

Mild aerobic exercise blocks elastin fiber fragmentation and aortic dilatation in a mouse model of Marfan syndrome associated aortic aneurysm.

Regular low-impact physical activity is generally allowed in patients with Marfan syndrome, a connective tissue disorder caused by heterozygous mutations in the fibrillin-1 gene. However, being above average in height encourages young adults with this syndrome to engage in high-intensity contact sports, which unfortunately increases the risk for aortic aneurysm and rupture, the leading cause of death in Marfan syndrome. In this study, we investigated the effects of voluntary (cage-wheel) or forced (treadmill) aerobic exercise at different intensities on aortic function and structure in a mouse model of Marfan syndrome. Four-week-old Marfan and wild-type mice were subjected to voluntary and forced exercise regimens or sedentary lifestyle for 5 mo. Thoracic aortic tissue was isolated and subjected to structural and functional studies. Our data showed that exercise improved aortic wall structure and function in Marfan mice and that the beneficial effect was biphasic, with an optimum at low intensity exercise (55-65% V̇o2max) and tapering off at a higher intensity of exercise (85% V̇o2max). The mechanism underlying the reduced elastin fragmentation in Marfan mice involved reduction of the expression of matrix metalloproteinases 2 and 9 within the aortic wall. These findings present the first evidence of potential beneficial effects of mild exercise on the structural integrity of the aortic wall in Marfan syndrome associated aneurysm. Our finding that moderate, but not strenuous, exercise protects aortic structure and function in a mouse model of Marfan syndrome could have important implications for the medical care of young Marfan patients.NEW & NOTEWORTHY The present study provides conclusive scientific evidence that daily exercise can improve aortic health in a mouse model of Marfan syndrome associated aortic aneurysm, and it establishes the threshold for the exercise intensity beyond which exercise may not be as protective. These findings establish a platform for a new focus on promoting regular exercise in Marfan patients at an optimum intensity and create a paradigm shift in clinical care of Marfan patients suffering from aortic aneurysm complications.

Aortic and Cardiac Structure and Function Using High-Resolution Echocardiography and Optical Coherence Tomography in a Mouse Model of Marfan Syndrome.

Marfan syndrome (MFS) is an autosomal-dominant disorder of connective tissue caused by mutations in the fibrillin-1 (FBN1) gene. Mortality is often due to aortic dissection and rupture. We investigated the structural and functional properties of the heart and aorta in a [Fbn1C1039G/+] MFS mouse using high-resolution ultrasound (echo) and optical coherence tomography (OCT). Echo was performed on 6- and 12-month old wild type (WT) and MFS mice (n = 8). In vivo pulse wave velocity (PWV), aortic root diameter, ejection fraction, stroke volume, left ventricular (LV) wall thickness, LV mass and mitral valve early and atrial velocities (E/A) ratio were measured by high resolution echocardiography. OCT was performed on 12-month old WT and MFS fixed mouse hearts to measure ventricular volume and mass. The PWV was significantly increased in 6-mo MFS vs. WT (366.6 ± 19.9 vs. 205.2 ± 18.1 cm/s; p = 0.003) and 12-mo MFS vs. WT (459.5 ± 42.3 vs. 205.3 ± 30.3 cm/s; p< 0.0001). PWV increased with age in MFS mice only. We also found a significantly enlarged aortic root and decreased E/A ratio in MFS mice compared with WT for both age groups. The [Fbn1C1039G/+] mouse model of MFS replicates many of the anomalies of Marfan patients including significant aortic dilation, central aortic stiffness, LV systolic and diastolic dysfunction. This is the first demonstration of the direct measurement in vivo of pulse wave velocity non-invasively in the aortic arch of MFS mice, a robust measure of aortic stiffness and a critical clinical parameter for the assessment of pathology in the Marfan syndrome.