Citations

In Marfan syndrome, mutations in the fibrillin gene are known to result in aortic dilatation and aneurysm formation, which is associated with impaired endothelial function and increased vascular stiffness. Previous studies suggested these phenotypes may be partly attributable to overactivation of TGF β signaling, which leads to increased reactive oxygen species production, extracellular matrix production, and increased matrix metalloproteinase activity in aortic wall. To our knowledge, however, there are no studies comprehensively evaluating the relationships between conduit vessel vasomotor function, vascular stiffness, and aortic dilatation in young and aged models of Marfan syndrome. Thus, the aim of this study was to test the hypothesis that carotid arterial vasomotor dysfunction and increased vascular stiffness precede aortic dilatation in fibrillin mutant mice. We used wild‐type (+/+) or fibrillin mutant (+/C1037G) mice fed a normal chow diet for 3 months (young) or 14 months (old), measured changes in vasomotor function and vascular stiffness in carotid arterial segments using pressurized arteriography, aortic dimensions using high resolution echocardiography, gene expression using qRT‐PCR, and protein levels using immunohistochemistry. Consistent with our hypothesis, young +/C1037G mice had impaired endothelium‐dependent relaxation to acetylcholine (ACH) compared to +/+ littermates, but did not exhibit changes in vascular stiffness. In contrast, old +/C1037G mice did not have significant changes in vasomotor responses to ACH compared to +/+ mice, but displayed markedly increased vascular stiffness compared to their wild‐type littermates. Aortic dimensions were significantly increased in young +/C1037G mice compared to their +/+ littermates, and these changes were exaggerated further with aging. Consistent with previous reports, we found increased TGF beta‐1 expression and canonical TGF beta signaling (p‐Smad2/3 levels) in +/C1037G mice. Interestingly, we also observed increased expression of Runx2 with aging in +/+ mice with aging, and expression of Runx2 was substantially increased in +/C1037G mice compared to their +/+ littermates at both time points. Collectively, our data show that vasomotor function and vascular stiffness in carotid arterial segments change independent of changes in aortic root diameter, suggesting significant heterogeneity in the mechanical and molecular responses to fibrillin deficiency throughout the vascular system. Support or Funding Information NHLBI (R01‐111121)

The structural protein, fibrillin, is important for maintaining the strength and reliability of connective tissue found in blood vessels and heart valves. Mutations in fibrillin‐1 result in Marfan syndrome and leads to left‐sided heart valve regurgitation, aortic root dilatation and aortic aneurysm. While previous studies have focused predominantly on young fibrillin‐mutant mice, hemodynamically significant disease generally does not emerge in patients with fibrillin mutations until later in life. Thus, this study aims to evaluate molecular and functional changes in heart valves from aged fibrillin mutant mice. Wild‐type (+/+) or fibrillin mutant (+/C1037G) mice were fed normal chow diet for 3 months (young) or 14 months (old). Heart valve function, aortic dimensions, and cardiac function were evaluated using high‐resolution echocardiography, and gene expression was measured using qRT‐PCR. Consistent with previous reports, we found no evidence of mitral regurgitation in young mice of either genotype. In old +/C1037G mice, however, we did find evidence of mitral regurgitation (~5%). In contrast, aortic valve regurgitation was evident in a relatively large proportion of +/C1037G mice at both ages (~20% at both time points), and was not detected in any +/+ animals. Interestingly, left ventricular dimensions were not associated with the presence of mitral regurgitation, but aortic root dilatation was present in all mice with aortic valve regurgitation. To gain insight into the molecular underpinnings of these phenotypic changes, we measured expression of IL‐10 (an anti‐inflammatory gene) and Runx2 (a pro‐proliferative gene that drives matrix remodeling), both of which are genes previously implicated in the pathogenesis of mitral and aortic valve disease. In young animals, expression of IL‐10 in mitral valves tended to be increased in +/C1037G mice compared to +/+ littermates. With aging, IL‐10 increased substantially in mitral valves from in +/+ mice, and increased further in +/C1037G littermates. Similar trends were observed in expression of Runx2 in mitral valves from both genotypes of mice. While IL‐10 followed a similar pattern in aortic valve tissue from young and old mice of both genotypes, Runx2 was not significantly increased across any of the groups. Collectively, while our data suggest that there are substantial, potentially adaptive molecular changes that occur during development of regurgitant valvular diseases, aortic dilatation may be a key early factor driving development of aortic regurgitation. Future experimental work aimed at determining the relative mechanical and molecular contributions to development of heart valve regurgitation will be critical to development of novel therapeutic strategies in patients with syndromes secondary to fibrillin mutations. Support or Funding Information NHLBI (R01‐HL111121)

Hypothermia/Rewarming (H/R) is poorly tolerated by the myocardium; however, the underlying intracellular basis of H/R‐induced cardiac injury remains elusive. We hypothesized that in cardiomyocytes, H/R leads to contractile dysfunction primarily through reduced Ca 2+ sensitivity of the myofilaments. To test this hypothesis, isolated rat cardiomyocytes (13–15 cells from 6 rats per group) were electrically stimulated to evoke both cytosolic Ca 2+ ([Ca 2+ ] cyto ) and contractile (sarcomere shortening) responses that were simultaneously measured using an IonOptix system. These measurements were subjected to the following temperature protocols: 1) hypothermia (15°C) followed by rewarming (35°C) or 2) time‐matched control (35°C). Contractile dysfunction after H/R was indicated by reduced shortening velocity and reduced extent of shortening of sarcomere length (SL) compared to time‐matched controls. Throughout hypothermia, basal [Ca 2+ ] cyto increased and the duration of the evoked [Ca 2+ ] cyto transients was prolonged. Phase‐loop plots of [Ca 2+ ] cyto versus contraction in cells exposed to H/R indicate that Ca 2+ sensitivity of contraction is reduced. Consistent with decreased Ca 2+ sensitivity, we found that cardiac troponin I (cTnI) phosphorylation (measured by Western blot) increased after H/R. Our results support our overall hypothesis and suggest that reduced Ca 2+ sensitivity and increased cTnI phosphorylation contributes to the altered excitation‐contraction coupling of cardiomyocytes following H/R. The clinical importance of our results brings focus to Ca 2+ sensitivity as a plausible therapeutic target in treating patients exposed to accidental hypothermia. Support or Funding Information NIH Grant 5T32HL10535 (NSS)

Hypothermia/Rewarming (H/R) induces myocardial dysfunction although the underlying intracellular mechanisms remain elusive. We hypothesized that in cardiomyocytes, H/R disrupts intracellular Ca 2+ ([Ca 2+ ] cyt ) homeostasis via an effect on both release and clearance of cytosolic Ca 2+ leading to a prolongation of evoked [Ca 2+ ] cyt transients associated with activation with downstream impact on contractility. To test this hypothesis, isolated rat cardiomyocytes (13–15 cells from 6 rats per group) were loaded with the Ca 2+ indicator, Fura‐2AM (0.5 μM), and exposed to H/R with or without electrical pacing at 0.5 Hz. In both groups, evoked [Ca 2+ ] cyt and contractile (sarcomere length (SL) shortening) responses were simultaneously measured at 35°C before and after hypothermia using an IonOptix system. H/R experiments were conducted as follows: experimental temperature was cooled from 35°C to 15°C in 30 min, maintained at 15°C for 2 h, and then rewarmed back to 35°C in 30 min. Time‐matched controls were implemented for 3 h at 35°C. With electrical pacing throughout hypothermia, basal [Ca 2+ ] cyt increased and the kinetics of the evoked [Ca 2+ ] cyt responses were prolonged. In addition, the extent and velocity of SL shortening was reduced in cardiomyocytes that were paced during hypothermia. In contrast, in cardiomyocytes that were not electrically paced during hypothermia, basal [Ca 2+ ] cyt was maintained and the kinetics of evoked [Ca 2+ ] cyt transients were unaffected. In addition, in the absence of pacing during hypothermia, contractility of cardiomyocytes was unaffected. These results suggest that H/R affects the release and clearance of evoked [Ca 2+ ] cyt transients (e.g., RyR mediated Ca 2+ release and SERCA mediated clearance) such that basal [Ca 2+ ] cyt increases. This effect of H/R on [Ca 2+ ] cyt homeostasis is associated with reduced cardiac contractility.

Background While recent work from our laboratory showed that DNA (cytosine‐5)‐methyltransferase 3 beta (DNMT3b) is significantly increased in tissue from humans with calcific aortic valve stenosis and is associated with increases in global genomic methylation, it is unknown whether the net effects of these changes are protective or deleterious. The objective of this study was to test the hypothesis that genetic reduction of DNMT3b allows for increased anti‐osteogenic gene expression, and consequently results in suppression of osteogenic signaling and slower progression of valvular stenosis. Methods We used Ldlr −/− /ApoB 100/100 (LA) mice that were wild‐type for DNMT3b (LA‐DNMT3b +/+ ) or deficient in DNMT3b (LA‐DNMT3b +/− ) and fed a western diet for six months. Results Using quantitative real‐time RT‐PCR, we confirmed that expression of DNMT3b was reduced by ~50% in valves from haploinsufficient mice. In line with our hypothesis, reductions in DNMT3b were associated with increases in expression of FABP4 (which opposes osteogenesis) and Smad6 (which opposes canonical BMP signaling). Similarly, expression of the osteogenic genes Msx2 and Spp1 were substantially reduced in DNMT3b‐deficient mice. Critically, aortic valve cusp separation distance was significantly greater in DNMT3b‐deficient mice, demonstrating slower progression of valvular dysfunction. No other gross abnormalities were noted in the mice. Conclusions Collectively, these data suggest that selectively reducing DNMT3b activity may be a viable therapeutic approach to slowing progression of calcific aortic valve stenosis in humans. Support or Funding Information Grant Funding Source: Supported by NHLBI

Importance: Phenol kits cleared by the Food and Drug Administration (FDA) are indicated as a topical anesthetic for the tympanic membrane (TM) in adults. However, there is no existing literature that reports outcomes to support the safety and use of phenol on the TM of awake children. Objective: Determine if topical phenol is safe and at low risk for complications and therefore be used effectively in awake children to facilitate office otologic procedures as in adults. Design, Setting, and Participants: Children under 21 years of age whose parents agreed to participate in an awake office setting for tympanostomy tube (TT) placement. All children had TT placement after phenol placement on the TM prior to insertion. Main Outcomes and Measures: TM perforation or other signs of TM complications through a minimum of 6-month clinical follow-up, along with assessment of the tolerability of the procedure by the child. Results: A total of 228 children with an age range of 6 months to 15.9 years and 435 TMs completed TT placement using phenol as a local anesthetic while awake in the office. There were no complications reported in the 204 children at the first follow-up visit post TM placement within 3 to 10 weeks. Of the 93 children followed up at least 6 months, there were no TM complications reported. Conclusions: This is the first study to report the outcomes on the use of phenol in an office setting in children. In this large experience, phenol appears to be tolerable and safe for use in young children in the office and is a potential safe choice of topical anesthesia for surgeons if they choose to perform office procedures such as myringotomies or TT placement on children.

Patients with advanced cancers who either do not experience initial response to or progress while on immune checkpoint inhibitors (ICIs) receive salvage radiotherapy to reduce tumor burden and tumor-related symptoms. Occasionally, some patients experience substantial global tumor regression with a rebound of cytotoxic CD8 + T cells. We have termed the rebound of cytotoxic CD8 + T cells in response to salvage therapy as T cell resilience and examined the underlying mechanisms of resilience. Resilient T cells are enriched for CX3CR1 + CD8 + T cells with low mitochondrial membrane potential, accumulate less reactive oxygen species (ROS), and express more malic enzyme 1 (ME1). ME1 overexpression enhanced the cytotoxicity and expansion of effector CD8 + T cells partially via the type I interferon pathway. ME1 also increased mitochondrial respiration while maintaining the redox state balance. ME1 increased the cytotoxicity of peripheral lymphocytes from patients with advanced cancers. Thus, preserved resilient T cells in patients rebound after salvage therapy and ME1 enhances their resiliency.

Abstract Background Atrial functional mitral regurgitation (AFMR) is an increasingly recognized cause of functional MR thought to result from left atrial enlargement and myopathy in the setting of preserved left ventricular geometry and function. AFMR mostly occurs in patients with atrial fibrillation (AF) and/or heart failure with preserved ejection fraction. Purpose We investigated whether the use of an artificial intelligence-based electrocardiogram (AI-ECG) can identify patients with new-onset AF and sinus rhythm (SR) who are at highest risk of developing AFMR. Methods Adults with a new diagnosis of AF between 2010 and 2021 who had a transthoracic echocardiogram (TTE) within 1 month after AF diagnosis were identified. Similarly, adults in SR who never had AF diagnosis and had a TTE during the same period were identified. Exclusion criteria from both groups included >mild MR at baseline, primary mitral valve disease, cardiomyopathy, ≥moderate aortic valve disease, current or previous low ejection fraction, enlarged left ventricle, cardiac devices, previous cardiac surgeries, and the absence of follow-up TTE ≥6 months from baseline. Only patients who had ECG within 10 days of the TTE were included. When multiple ECGs were available, the closest was considered. A previously trained AI-ECG algorithm to detect the probability of AF was utilized. Incident AFMR was defined as >mild functional MR in the absence of >mild left ventricle enlargement or dysfunction. Diastolic dysfunction was defined according to ASE/EACVI guidelines. Results Overall, 1,570 patients with new-onset AF (median age 67 years; 34% females) and 16,802 patients in SR (median age 59 years; 46% females) were included. The median AI ECG probability for AF was 43% (IQR 26%-59%) in the new-onset AF group and 2% (0.5%-7%) in the SR group, Figure 1. Incident AFMR occurred in 152 patients in the AF group over median 3.06 (IQR 1.5-5.2) years of follow-up and in 482 patients in the SR group over median 3.0 (1.5-5.6) years of follow-up. The probability of silent AF by the AI-ECG was associated with incident AFMR in the new-onset AF group [hazard ratio 1.19 (95% CI 1.11-1.28) per 10%, p <.001] and the SR group [hazard ratio 1.19 (95% CI 1.12-1.25) per 10%, p <.001]. The AI ECG-derived AF probability remained as an independent risk factor for AFMR in multivariable analysis in both AF and SR, Table 1. Conclusion The AI ECG for AF might be able to reflect the degree of left atrial myopathy and thus the risk of incident AFMR in patients with AF and SR.Distribution of AI ECG probability of AFMultivariable risk factors for AFMR

Abstract Background Atrial fibrillation (AF) is associated with increased risk of incident tricuspid regurgitation (TR), but types of incident TR in AF versus sinus rhythm (SR) are not well-defined. Purpose We aimed to compare the risk of the different types of incident ≥moderate TR in AF and SR. Methods Adults first diagnosed with AF (2010-2021) who had a transthoracic echocardiogram (TTE) within 30 days after AF and adults with no diagnosis of AF who had a TTE in the same period were identified. Patients with previous cardiac surgeries, congenital heart disease, cardiomyopathy, cardiac devices, primary valve disease, previous or current ejection fraction (EF) <50%, severe diastolic dysfunction (SDD), ≥moderate left-sided valve disease (LVD), right ventricular systolic pressure (RVSP) ≥50 mmHg, ≥moderate TR, any tricuspid stenosis, or with no follow-up TTE ≥6 months from baseline were excluded. Patients were followed for the development of ≥moderate TR, the type of which was identified in a hierarchal order: 1) pacemaker-associated TR, 2) LVD-associated TR in the setting of ≥moderate LVD, 3) low EF or SDD-related TR, 4) pulmonary hypertension (PH)-associated TR if RVSP was ≥50 mmHg, 5) other ventricular functional TR (VFTR) if there was >mild RV enlargement or dysfunction, and 6) atrial functional TR (AFTR) when none of the previous was present. Patients were also followed for the occurrence of risk factors for TR (pacemaker insertion, ≥moderate LVD, low EF or SDD, PH, >mild RV enlargement or dysfunction) in a hierarchal order, and both the prevalence and future risk of the corresponding type of ≥moderate TR was determined at the onset of these conditions in AF and SR. Results Overall, 1,360 patients with new-onset AF (median age 67 years, 34% females) and 20,438 patients in SR (median age 60 years; 54% females) were included. Over median 3.8 (IQR 1.8-6.6) years, incident ≥moderate TR occurred in 110 patients with new-onset AF [2.13 per 100-person years] compared to 378 patients in SR [0.41 per 100-person years, p <.001]. All types of incident ≥moderate TR occurred more frequently in AF (p <.001 for all). The distribution and incidence of each type of TR in AF and SR are shown in Figure 1. The incidence of risk factors associated with the development of TR was higher in the AF group, except for pre-capillary PH, Figure 2A. At time of diagnosis or occurrence of these conditions, the prevalence of the corresponding TR types was higher in AF, except for pacemaker-TR, Figure 2B. The incidence of the corresponding TR type after occurrence of TR risk factors was higher in the AF group for LVD-TR and low EF/SDD-associated TR (p ≤0.03); although numerically higher in AF, the association was only borderline for PH-TR (p =0.05), Figure 2C. Conclusion Incident ≥moderate TR of all types occurred more frequently in patients with AF vs. SR and the distribution of TR types differed by rhythm. Patients with AF may benefit from a closer follow-up.Distribution and incidence rates of TRIncidence of TR risk factors & TR after

Abstract Background Atrial fibrillation (AF) and heart failure with preserved ejection fraction (HFpEF) are closely associated diseases that frequently coexist. However, due to the overlapping symptoms, the diagnosis of HFpEF can be overlooked with symptoms being attributed to AF. Purpose We aimed to investigate the prevalence of diastolic dysfunction (DD) in patients with new-onset AF compared to sinus rhythm (SR), study changes in diastolic function parameters over time in the two groups and compare the incidence of DD at follow-up. Methods Adults with new diagnosis of AF and adults in SR were identified. Patients with previous cardiac surgeries, congenital heart disease, hypertrophic or infiltrative cardiomyopathy, primary mitral disease, left-sided valve disease, low ejection fraction, enlarged left ventricle, or with no 6-month follow-up echocardiogram were excluded. Diastolic function was assessed through 4 components: mitral medial e’ <0.07 m/sec, mitral medial E/e’ >15 in SR and >11 in AF, TR velocity >2.80 m/sec, and left atrial volume index >34 ml/m2, with severe DD (SDD) defined by ≥3/4 findings and moderate DD (MDD) by ≥2/4 abnormal diastolic function parameters. Annualized changes were calculated as the difference between follow-up and baseline values divided by years in between. In a secondary analysis, patients with new-onset AF were propensity score-matched to patients with SR in a 3:1 ratio based on age, sex, body mass index, and comorbidities. Results Overall, 1,747 patients with incident AF (median age 67 years; 34% females) and 29,623 in SR (median age 59 years; 51% females) were included. New-onset AF was independently associated with the presence of SDD vs SR (8% vs 2%) and MDD (25% vs 11%, p<.001 for both in adjusted analysis). Over median follow-up of 3.2 (IQR 1.6-5.8) years, annualized severity progression in each of the 4 diastolic function parameters was greater in the AF group (p<.001 for all), Table. The incidence rates of SDD and MDD were 3.7 and 8.8 per 100-person year, respectively, in AF versus 1.1 and 3.6 per 100-person years, respectively, in SR (p<.001 for both at univariate and multivariable analysis), Figure. Results were similar in the propensity-score matched analysis. Conclusions Patients with new-onset AF more commonly have moderate or severe diastolic dysfunction that indicates the presence of potentially overlooked clinical HFpEF (when symptoms exist) or preclinical HFpEF (when symptoms are absent) compared to patients in SR. In long-term follow-up, patients with AF display accelerated progression in DD; suggesting that therapies to prevent progression to symptomatic HFpEF may be highest value in this patient population.