Lerman, Amir

BACKGROUND: The immunologic risk associated with preformed donor-specific allo-antibodies (DSA) against human leukocyte antigens (HLA) in heart transplant (HTX) recipients is unclear. The goal of this study was to evaluate potential role of DSA on the progression of cardiac allograft vasculopathy (CAV) in HTX recipients. METHODS: The presence of DSA against HLA was evaluated using solid phase Single Antigen Bead assay (One Lambda, Inc., Canoga Park, CA; Luminex platform) before transplant in 35 HTX recipients. Using alloantibody specification analysis, 11% (4/35) and 20% (7/35) had DSA against donor Class I and II HLA respectively including the one patient who had both (DSA I & II+) . 71% (25/35) of patients had no demonstrable DSA (DSA-). All patients had negative cytotoxicity cross match. Baseline three-dimensional intravascular ultrasound studies (3D IVUS) were performed at 1.0 [0.18, 1.4] year after transplant. Follow up 3D IVUS exams were performed 0.92 [0.85, 1.04] years after the baseline exam. RESULTS: The increase in mean plaque (media and intima) volume (PV) was accelerated in the DSA II+ group as compared to the DSA- group (0.87±1.9 mm (3)/mm vs. 0.16±1.8 mm (3)/mm) but the vessel volume index (follow up vessel volume/ baseline vessel volume) was similar between groups (1.08±0.5 vs. 1.09± 0.4; p=0.9). Plaque index (PI) (PV/vessel volume x 100 [%]) increased significantly in the DSA II+ group (17.9±6.3%) but not in the DSA- group (-13.6±13.2%, P=0.02). None of these values were significant in the DSA I+ only group. Treatment with Sirolimus did not affect PI progression between the DSA II+ and DSA- groups (PI progression: 15.9±8.7% vs. -11.7±7.1%, P=0.03). Age, gender, lipid and uric acid levels, prevalence of diabetes, ischemic time, time between IVUS examinations, the use of steroids, mycophenolate vs. azathioprine or calcineurin inhibitors vs. sirolimus were not different between the groups (P>0.4 for all). CONCLUSIONS: Heart transplant recipients with clearly defined anti-Class II DSA are at risk for accelerated cardiac allograft vasculopathy. Whether interventions to minimize the risk of DSA such as virtual crossmatch, desensitization and complement inhibition will retard CAV remains to be proven.

Objective To test the hypothesis that the numbers of circulating endothelial progenitor cells (EPC) co-expressing an osteogenic phenotype (EPC-OC) are increased in patients with clinically severe calcific aortic valve stenosis (AoC). Background AoC is one of the most common valvular heart diseases. Recent studies have shifted the old paradigm of AoC being a passive, degenerative process to an active biological process associated with an osteoblast-like phenotype. We have recently identified circulating EPC-OC which are significantly increased in patients with severe coronary artery disease (CAD). Methods and Results Of 38 patients, 14 underwent aortic valve replacement due to AoC with only mild angiographic CAD. Patients with normal aortic valves and coronary arteries (n=12) or severe CAD without aortic valve disease (n=12) served as controls (Table ). Peripheral blood mononuclear cells were analyzed using flow cytometry following staining for EPC markers (CD133, CD34, KDR) and the osteoblastic marker, osteocalcin (OC). Patients with AoC had significantly higher fractions of OC co-expression on EPC of different maturity than normal patients, similar to patients with CAD (Figure ). Conclusions Circulating EPC co-expressing an osteoblastic phenotype are increased and may potentially play a role in the active process of aortic valve calcification. Table. Clinical Data.

Increased oxidative stress has been suggested to play an important role in the biology of mesenchymal stem cells (MSCs). However, little is known of the effect of increased oxidative stress in-vivo, partly due to the lack of appropriate imaging technologies for monitoring of stem cell biology in the living subject. Recent developments in molecular imaging permit, for the first time, the longitudinal monitoring of stem cell biology in vivo. We hypothesize that changes in oxidative stress can be monitored using a reporter gene strategy (molecular imaging). Methods: We have developed a novel oxidative stress sensor, using a two-step transcriptional amplification strategy to enhance the expression of firefly luciferase (Fluc), driven by the pro-oxidant enzyme NAD(P)H promoter, and used to monitor oxidative stress in rMSCs. rMSCs was induced by hypoxia (1% O2 for 24 hours) and serum deprivation (SD) and confirmed using a dichlorofluorescein colorimetric assay (measures the production of hydrogen peroxide-H2O2-) and NAD(P)H protein expression. Results: Both serum deprivation and hypoxia led to a pro-oxidant state (Fig. A–B ). Most importantly, increased oxidative stress led to increased activity of the novel reporter gene sensor (Fig. C ) which was decreased in the presence of antioxidants (superoxide dismuatse mimetic Tempol, 5mM, SD+T, Fig D ). Results were reproduced in a different cell type (rat cardiomyoblast, data not shown). Conclusion: Changes in oxidative stress in MSCs can be monitored using molecular imaging. Reporter Gene-based Molecular Imaging, a strategy that is clinically applicable, provides the opportunity to monitor stem cell survival in the living subject.

Background Coronary microvascular dysfunction (CMD) represents an early functional characteristic of coronary vascular aging. Klotho (α‐klotho) is a circulating protein inversely linked to physiological aging. We examined low klotho as a potential marker for vascular aging in patients with CMD and no coronary artery disease. Methods and Results Patients undergoing nonurgent angiogram for chest pain who had no coronary artery disease underwent invasive coronary microvascular and endothelial function testing. CMD was defined by ≤50% increase in coronary blood flow (percentage change in coronary blood flow) in response to intracoronary acetylcholine or coronary flow reserve ≤2. Fresh arterial whole blood was used to analyze circulating endothelial progenitor cells with flow cytometry. Stored arterial plasma was used for klotho analysis by ELISA. Participants with CMD (n=62) were compared with those without CMD (n=36). Those with CMD were age 55±10 years (versus 51±11 years; P =0.07) and 73% women (versus 81%; P =0.38). Traditional risk factors for coronary artery disease were similar between groups. Patients with CMD had less klotho (0.88±1.50 versus 1.75±2.38 ng/mL; P =0.03), and the odds of low klotho in CMD were significant in a logistic regression model after adjusting for traditional cardiovascular risk factors (odds ratio [OR], 0.80 [95% CI, 0.636–0.996]; P =0.05). Higher klotho was associated with higher numbers of endothelial progenitor cells with vascular regenerative potential (CD34 + and CD34 + CD133 + KDR + ). Among a subgroup of patients with atherosclerotic cardiovascular disease risk <5% (n=58), CMD remained associated with lower klotho (OR, 0.80 [95% CI, 0.636–0.996]; P =0.047). Conclusions Klotho may be a biomarker for CMD and may be a therapeutic target for groups of patients without significant traditional cardiovascular risk.

Background Recent studies have indicated high rates of future major adverse cardiovascular events in patients with Takotsubo cardiomyopathy (TC), but there is no well‐established tool for risk stratification. This study sought to evaluate the prognostic value of several artificial intelligence‐augmented ECG (AI‐ECG) algorithms in patients with TC. Methods and Results This study examined consecutive patients in the prospective and observational Mayo Clinic Takotsubo syndrome registry. Several previously validated AI‐ECG algorithms were used for the estimation of ECG‐ age, probability of low ejection fraction, and probability of atrial fibrillation. Multivariable models were constructed to evaluate the association of AI‐ECG and other clinical characteristics with major adverse cardiac events, defined as cardiovascular death, recurrence of TC, nonfatal myocardial infarction, hospitalization for congestive heart failure, and stroke. In the final analysis, 305 patients with TC were studied over a median follow‐up of 4.8 years. Patients with future major adverse cardiac events were more likely to be older, have a history of hypertension, congestive heart failure, worse renal function, as well as high‐risk AI‐ECG findings compared with those without. Multivariable Cox proportional hazards analysis indicated that the presence of 2 or 3 high‐risk findings detected by AI‐ECG remained a significant predictor of major adverse cardiac events in patients with TC after adjustment by conventional risk factors (hazard ratio, 4.419 [95% CI, 1.833–10.66], P =0.001). Conclusions The combined use of AI‐ECG algorithms derived from a single 12‐lead ECG might detect subtle underlying patterns associated with worse outcomes in patients with TC. This approach might be beneficial for stratifying high‐risk patients with TC.

Coronary artery calcification (CAC) accompanies the development of advanced atherosclerosis. Its role in atherosclerosis holds great interest because the presence and burden of coronary calcification provide direct evidence of the presence and extent of coronary artery disease; furthermore, CAC predicts future events independently of concomitant conventional cardiovascular risk factors and to a greater extent than any other noninvasive biomarker of this disease. Nevertheless, the relationship between CAC and the susceptibility of a plaque to provoke a thrombotic event remains incompletely understood. This review summarizes the current understanding and literature on CAC. It outlines the pathophysiology of CAC and reviews laboratory, histopathological, and genetic studies, as well as imaging findings, to characterize different types of calcification and to elucidate their implications. Some patterns of calcification such as microcalcification portend increased risk of rupture and cardiovascular events and may improve prognosis assessment noninvasively. However, contemporary computed tomography cannot assess early microcalcification. Limited spatial resolution and blooming artifacts may hinder estimation of degree of coronary artery stenosis. Technical advances such as photon counting detectors and combination with nuclear approaches (eg, NaF imaging) promise to improve the performance of cardiac computed tomography. These innovations may speed achieving the ultimate goal of providing noninvasively specific and clinically actionable information.

Introduction: α-Klotho (klotho) is a geroprotective protein inversely associated with coronary artery disease CAD and vascular aging. This study used intravascular ultrasound (IVUS) to study coronary artery plaque characteristics of patients with low circulating klotho. Hypothesis: Lower klotho is associated with vulnerable coronary artery plaque characteristics. Methods: Patients undergoing coronary angiogram for chest pain who had no CAD (<40% stenosis) underwent IVUS assessment. Images were obtained from the mid-LAD to the coronary ostium. Stored arterial plasma was used for α-klotho analysis by enzyme-linked immunosorbent assay. Results: A total of 58 consecutive patients were retrospectively studied. The median circulating klotho level of the cohort was 0.27 ng/mL [0.15; 1.24]. Patients with klotho less than the median were compared to those with levels greater than or equal to the median and were similar in age (53 ±11 vs. 56 ±10, p = 0.235) and sex distribution (86% vs. 76% female, p = 0.324). Patients with less klotho had higher coronary plaque burden (21.42% [17.185, 31.955] vs. 18.32 [10.5, 24.515], p=0.041) and larger plaque area (2.71 [2.03, 4.605] vs . 2.27 [1.41, 3.31] mm 3 /mm, p=0.058) compared to those with higher klotho. Lower klotho was associated with vulnerable plaque characteristics, including greater percentages of dense calcium (1.33% [0.265, 5.38] vs. 0.43% [0.015, 1.73], p=0.037) and necrotic core (5.43% [2.245, 10.5] vs. 2.22% [0.86, 4.50], p=0.011). Conclusions: Lower circulating klotho was associated with higher coronary plaque burden and vulnerable plaque characteristics. Klotho may be an early biomarker for risk in coronary artery disease.

Background: Depression is prevalent in almost half of patients with cardiovascular disease (CVD) and is associated with CVD and mortality. We used an artificial intelligence algorithm using ECG that predicts physiological age (ECG-Age) that has been linked to increased total and CVD mortality and CVD risk factors. We hypothesized that depressive symptoms would be associated with physiologic aging, as measured by AI-ECG Methods: A previously validated algorithm was applied to determine ECG-Age to 105,732 consecutive ECGs of individuals age ≥18 who sought care at Mayo Clinic between June 2019 and January 2022 and filled the Patient Health Questionnaire-9 (PHQ-9) within a month of ECG. PHQ-9 ascertains severity and frequency of depressive symptoms with values from 0 - 27 and were categorized as (None≤4, Mild 5-9, Moderate 10-14, Moderately severe 15-19 and Severe ≥20). Delta-Age was defined as ECG-Age minus chronological age and accelerated aging was defined as a Delta-Age >1SD above the mean. Logistic regression analyses associated PHQ-9 scores with positive Delta-Age while adjusting for CVD risk factors Results: Mean chronological age was 57±17 yr and mean ECG-Age 58±14 yr (R2 0.85, P < 0.0001), Delta-Age 0.71±9.40 yr, 58% women, average PHQ-9 5±6, 61% had none, 20% mild, 10 % moderate, 5%moderately severe and 4% had severe depressive symptoms. Delta-Age was 2.10 years higher in those with depressive symptoms, reflecting accelerated aging. Compared to those with no depressive symptoms, those with severe symptoms were 1.5 times more likely to have Delta-Age >1SD (OR 1.52 CI 95%1.73-1.33), independently of CV risk factors and the Charlson comorbidity index. Figure. There is significant attenuation of the association once accounting for age, sex and CVD risk factors Conclusions: Depressive symptoms are associated with physiologic aging, highlighting the role of depression in physiologic aging and the potential of preventive strategies in patients with depression and CVD

Introduction: Metabolically obese normal weight (MONW) refers to metabolic abnormalities despite normal body mass index (BMI). Hypothesis: Because obesity is generally defined by BMI, it is assumed that people with MONW do not have excessive adiposity but still have the metabolic dysregulation associated with adiposity. Methods: We included participants aged 20-65 of the National Health and Nutrition Examination Surveys from 1999-2006 and 2011-2018 with normal BMI (18.5-25 kg/m 2 ), fasting blood samples, and DEXA data. According to the AHA criteria, MONW was defined having ≥3 of the following criteria, besides a normal BMI: Hypertriglyceridemia (≥ 150 mg/dL) or treatment for elevated triglycerides; HDL cholesterol level < 40 mg/dL in men or <50 mg/dL in women or treatment for reduced HDL-C; elevated blood pressure (systolic ≥ 130 mmHg and/or diastolic ≥ 85 mmHg) or antihypertensive treatment or history of hypertension; elevated fasting plasma glucose ≥ 100 mg/dL or insulin/oral hypoglycemic treatment and central obesity by waist circumference (≥ 94 cm in men and ≥ 80 cm in women). High fat percentage was defined as ≥25% in men, ≥35% in women. Weighted logistic regression was performed to test the relation between MONW and high fat%, central obesity. Results: Of the 7,887 participants (53.6% men; mean age±SE was 39.23±0.24 years), 2433 (33.4%) had normal BMI included in the analysis. Among these, 148 had MONW (5%). Mean Fat% was 26.08±0.36% in those with MONW versus 21.90±0.17% in those without MONW for men, and 37.02±0.35% versus 33.31±0.21% for women. MONW subjects were 2.21 times more likely to have either central obesity or high fat % (OR 12.09, 95%CI: 6.18-23.67, p<0.01) and 2.18 times more likely to have high fat % (OR=2.84, 95%CI: 1.72-4.67, p<0.01) (see Figure). Conclusions: Most individuals with MONW have either increased fat content, central deposition of fat, or both. That highlights people with normal BMI may still have metabolic complications of adiposity.

Background: The role of body adiposity on metabolic dysregulation in subjects with normal body mass index (BMI) is still under debate with limited population-based evidence. Hypothesis: Body adiposity measured by dual x-ray absorptiometry (DEXA) is associated with metabolic disorders in normal-weight individuals. Methods: We evaluated a sample of adults aged 20-65 who underwent DEXA in the US National Health and Nutrition Examination Surveys from 1999-2006 and 2011-2018. We excluded those with history of cardiovascular disease, cancer, and chronic obstructive pulmonary disease. Weighted logistic regression was performed to test the association between body fat percentage (BF%) and metabolic disorders [e.g., insulin resistance (IR), metabolic syndrome (MS), dyslipidemia, type 2 diabetes mellitus (DM), hypertension]. Models were adjusted for potential confounders while considering complex survey design and were further stratified by sex and BF% as tertiles in normal-weight individuals. IR was tested as a secondary analysis to evaluate the effect on the predicted risk. Results: We included 20,613 individuals (51.5% men, 65.4% non-Hispanic whites), mean age ± SE was 39.42±0.22 years, and 6,424 were normal weight by BMI and represented our study sample. The overall BF% in these subjects measured by DEXA was 28.41±0.19%. In our cohort, metabolic disorders were prevalent in 2.1% to 40.4% of patients (Table 1). Every 10-unit % increase in total BF% was associated with a higher risk for IR, MS, dyslipidemia in the normal weight BMI group (Table 1). Metabolic disorders were associated with BF% tertiles (Figure 1). IR was significantly associated with body fat across all BF% tertiles for men and highest tertiles for women (Figure 2). Conclusion(s): Less than 1/3 of subjects in a representative national sample had a normal BMI. Even in these “normal weight” subjects, increases in body adiposity are significantly associated with increased cardiometabolic disease burden.