Citations

Background: Heart failure with preserved ejection fraction (HFpEF) accounts for approximately half of all heart failure hospitalizations; yet, tools for individualized 1-year mortality risk stratification remain limited. We conducted a retrospective study to develop and validate a machine learning model using genetic programming and automated model search to predict 1-year all-cause mortality in HFpEF patients admitted for decompensated HF. Methods: Electronic medical records from Mayo Clinic (2010-2020) were queried to identify 7,840 adult patients hospitalized with HF exacerbation and a left ventricular ejection fraction>50% on echocardiograms performed between six months pre-admission and seven days post-discharge. Demographic, clinical, laboratory, medication, comorbidity, and imaging data available at the time of index hospitalization were extracted. The cohort was split into 80% training (n=6,272) and 20% held-out test (n=1,568) sets. After standard preprocessing, we performed an evolutionary AutoML search. The final pipeline applied a RobustScaler, two sequential feature-union blocks, and an XGBoost classifier. Model performance on the test set was assessed by area under the receiver operating characteristic curve (AUC), Brier score, accuracy, precision, recall, and F1 score, each with bootstrap-derived 95% confidence intervals (CIs). For interpretability, SHAP (SHapley Additive exPlanations) values were computed using the full scaled training set as background. Results: On the held-out test set, the XGBoost-based model achieved an AUC of 0.7595 (95% CI: 0.7307-0.7870) and a Brier score of 0.1764 (95% CI: 0.1652-0.1890). Accuracy was 0.7406 (95% CI: 0.7143-0.7645), precision 0.6349 (95% CI: 0.5759-0.6942), recall 0.4135 (95% CI: 0.3636-0.4609), and F1 score 0.5008 (95% CI: 0.4529-0.5444). The global SHAP summary plot (Figure 1) ranked age, serum albumin, blood urea nitrogen (BUN), presence of renal failure, and NT-proBNP as the top 5 predictors. Conclusions: In this large HFpEF cohort, an AutoML-derived XGBoost pipeline achieved robust discrimination (AUC≈0.76) and calibration (Brier≈0.18) for 1-year mortality prediction. SHAP-based explanations highlighted the importance of age, nutritional status (albumin), renal biomarkers (BUN, renal failure), and natriuretic peptides (NT-proBNP) as principal drivers of risk. These interpretable machine learning findings may guide personalized risk stratification and identify therapeutic targets in HFpEF.

Abstract Background One in five adults aged 40 will develop heart failure (HF) during their lifetime. Risk factors (e.g., hypertension, diabetes mellitus, coronary artery disease, etc.) lead to structural and functional changes in cardiomyocytes, resulting in HF. At the cellular level, these changes consist of mis/over‐expression of genes that regulate cardiac identity (e.g., CamK2δ, PKC, Stat3, etc.). The current paradigm for treating HF is pharmacological or device‐based intervention; however, with few exceptions, the condition worsens with time. We are proposing to implement a change in HF treatment, shifting from a drug‐centric system to a cardiac target‐specific molecular approach that would reverse hypertrophy and adverse remodelling of affected cardiomyocytes. Methods A cardiomyocyte targeting peptide (CTP) was reversibly linked to miRNA106a for delivery to a mouse model of HF. Reversal of morphological, signalling, and physiological HF parameters was measured. Additionally, CTP‐miRNA106a was introduced into a human cardiomyocyte cell line to identify mechanism(s) at play for reversing HF characteristics (e.g., hypertrophy). Results Bio‐distribution studies showed that intravenously injected CTP‐miRNA106 delivered its cargo specifically to the heart within 30 min, followed by clearance of CTP from the heart to the kidneys, and to a lesser extent, the liver by 35 h with persistence of miRNA106a in cardiomyocytes until day 7 (the latest tested time‐point). CTP‐miRNA106a reversed angiotensin2/isoproterenol‐induced hypertrophy in 90% of the treated mice. We also identified two potential HF intracellular signalling pathways/mechanisms (PLCβ1/PKC/IP3 and NF‐κB) targeted by CTP‐miRNA106a that could benefit many pathophysiologies underlying HF, including inflammation. Conclusions CTP‐miRNA106a, a first‐of‐a‐kind cardiac‐specific drug, downregulates genes involved in cardiac hypertrophy and inflammation through the PLCβ1 and CamKIIδ kinase pathways. CTP delivery of miRNA106a cargo is specific to cardiomyocytes both in vitro and in vivo, and once delivered, many HF parameters, including hypertrophy, are reversed. Key points Cardiac Targeting Peptide (CTP) delivers, specifically to the heart, reversibly linked miRNA106a. MiRNA106a targets genes in various pathways known to cause heart failure when they are over/hyper activated returning their expression to normal levels. In vivo analyses using a mouse heart failure model resulted in reversal of heart failure parameters in 19/20 mice.

Background: Cell-penetrating peptides cross cell membrane barriers while carrying cargoes in a functional form. Our work identified two novel lung-targeting peptides, S7A and R11A. Here, we present studies on biodistribution, the cell types targeted, and an in vitro proof of application. Methods: Studies were performed in human bronchial epithelial cells (HBECs) with and without various endocytic inhibitors, and coincubation with fluorescently labeled transferrin or endocytic markers. Cyclic R11A (cR11A) was conjugated to siRNA duplexes and anti-viral activity against SARS-CoV-2 was tested. Biodistribution studies were performed by injecting wild-type mice with fluorescently labeled peptides, and various circulation times were allowed for, as well as cross-staining of lung sections or isolated single cells with various cellular markers, followed by fluorescence-activated cell sorting or confocal microscopy. Results: cR11A showed peak uptake in 15 min, with the highest uptake in airway epithelial type II (ATII) cells, followed by p63+ basal cells and ionocytes. Cyclization increased transduction efficiencies ~100-fold. Endocytosis studies showed a decrease in peptide uptake by pre-treatment with Pitstop2 but not Amiloride or Nystatin. Endocytic marker Lamp1 showed colocalization at the earliest time point, with the escape of the peptide from endocytic vesicles later. cR11A conjugated to ant-spike and anti-envelop proteins showed anti-viral effects with an EC90 of 0.6 μM and 1.0 µM, respectively. Conclusions: We have identified a novel peptide, cR11A, that targets ATII, basal cells, and ionocytes, the cyclization of which increased transduction efficiency in vitro and in vivo. The uptake mechanism appears to be via clathrin-mediated endocytosis with escape from endocytic vesicles. cR11A can act as a vector to deliver anti-viral siRNA to epithelial cells.

The radiotracer [ 68 Ga]Ga-NOTA-CTP was evaluated in healthy and diseased CD1 mice with myocardial infarction following ligation of the left anterior descending artery.

Introduction: Heart failure with preserved ejection fraction (HFpEF) is an increasingly prevalent form of heart failure (HF) in the US today. Our prior work revealed low albumin at first hospitalization for HF exacerbation with underlying HFpEF to be an independent predictor of all-cause mortality in a small cohort of patients. We now sought to confirm our earlier findings across a larger and more diverse patient population. Methods: Seven thousand, eight hundred and forty patients had a first admission to Mayo Clinic for HF exacerbation with an echo-confirmed left ventricular ejection fraction>50% between 2010 and 2020. Patient baseline demographics, co-morbidities, admission laboratory values, echocardiographic parameters, discharge medications, and outcomes were obtained from chart abstraction. To validate our previous model, patients were grouped based on the number of risk factors as previously defined: age>80 years, serum albumin level<3.2 g/dl, medial E/e'≥20, N-terminal pro-brain natriuretic peptide (NT-proBNP) >5,000 pg/mL, and the presence of hypertension (HTN). The association with 1 year mortality was studied using Cox regression. Kaplan Meier curves were generated based on the number of factors present per patient. Results: Eleven significant univariate predictors of all-cause mortality were identified from the data (Fig. 1A), with hazard ratios (HR) ranging from 1.22-2.04 (p<0.001 for all). Notably, four previously identified prognosticators (age, albumin, medial E/e’, , HTN) were noted as significant independent predictors of all-cause mortality in HFpEF (HR 1.67, 2.14, 1.18, and 1.15, respectively, p<0.004 for all ; Fig. 1B). Multivariate regression modeling identified low albumin on presentation as being a significant adverse prognosticator (HR=2.14; p-value<0.001). Conclusion: Our analysis of 7840 HFpEF patients confirms our prior findings, suggesting that this model is a strong predictive tool for assessing the prognosis of HFpEF. Taken together, these five variables are easily available in the in-patient setting and can be incorporated into a model predictive of 1-year all-cause mortality.

Introduction: Intracellular calcium handling plays a central role in cardiac contractility and relaxation. Genes such as the Ca 2+ -ATPase pump (SERCA2a) and the Dihydropteridine reductase (DHPR) enzyme are especially important in the cycling of intracellular calcium. As prior research has established a link between treatment with our cardiac targeting peptide (CTP: a 12-amino acid, cardiomyocyte-specific cell penetrating peptide) and upregulation of calcium-handling genes such as SERCA2a and DHPR, we hypothesized that treatment with our novel hybrid cardiac targeting peptide (hCTP: positions #3 and 11 replaced with the D-enantiomer form of the amino acids) will improve intracellular calcium handling in human cardiomyocytes (CMCs) by increasing expression of key calcium handling genes instrumental in sequestering calcium in diastole and lowering cytosolic levels. Methods: To test hCTP’s calcium handling abilities, CMCs were plated on day 1 and allowed to settle for 24 hours, after which they received daily treatment with various concentrations of hCTP (1-25µM) for three days. On day 5, cells underwent either intracellular calcium measurements using the FLIPR 6 Calcium assay or were prepared for western blotting. Western blotting was performed to determine the protein concentrations of SERCA2a and DHPR, as compared to a GAPDH control. To test hCTP’s intrinsic calcium handling abilities, various concentrations of hCTP were mixed with a constant amount of elemental calcium dissolved in water. After 20 min at 37 o C, the concentration of free Ca 2+ was measured with an ABL90 Flex Plus radiometer. Results: In CMCs, treatment with hCTP led to a decrease in cytosolic calcium in a dose dependent fashion; concentrations as low as 1µM led to a significant decrease in cytosolic calcium (p< 0.0001 for all groups). Western blots performed on the treated CMCs revealed an increase in expression of both DHPR and SERCA2a, normalized to GAPDH control. Outside of the cellular environment, hCTP did not appear to display inherent calcium sequestring properties, suggesting that improvements in calcium handling are due to upregulation of gene expression. Conclusion: hCTP appears to lower cytosolic calcium and improve calcium handling through upregulation of SERCA2a and DHPR. Our data indicates that hCTP is worth pursuing as a stand-alone, cardio-selective therapy for cardiomyopathies involving calcium mishandling.

Introduction: Role of NF-κB driven inflammation leading to heart failure with preserved ejection fraction has received little attention. Our previous in vivo work with cardiac targeting peptide (CTP) in guinea pigs identified suppression of NF- κB pathway by CTP. In the current work we sought to further study the effects of a hybrid version of CTP (hCTP: amino acids at positions 3 and 11 substituted with D-amino acids) on TNF-α mediated NF-κB activation, as well as expression of its downstream inflammatory markers IL-1β and IL-8. Methods: Human cardiomyocytes (CMCs) were transfected using Lipofectamine 3000 with a reporter luciferase plasmid carrying an NF-κB promoter site upstream of the luciferase gene. Cells were treated with various concentrations of hCTP for 24 hours, followed by a TNF-α challenge (20ng/mL), addition of luciferin as substrate, and measurement of luminescence. Cell viability in response to above manipulations was assessed by FACS using live-dead stain. CMCs were treated as above, and cell culture supernatants analyzed for IL-8 levels using human ELISA kit. In another set of experiments, CMCs were transfected with NF-κB reporter plasmid, and after treatment for 24 hours with various concentrations of hCTP, incubated with 10nM angiotensin 2 (Ang2) and 100nM phenylephrine (PE) for 24hrs to assess levels of IL-1β in the cell culture media using an ELISA assay. Results: hCTP inhibited TNF-α mediated NF-κB activation with a dose-response curve, with maximum inhibition with hCTP seen at 10µM concentrations (p<0.001). Treatment with hCTP inhibited the TNF-α induced IL-8 secretion with significant decreases seen even at the 1µM dose. Similarly, secretion of IL-1β production by CMCs in response to Ang2/PE stimulation was suppressed by hCTP even at the lowest tested dose (1µM; p<0.5). Conclusions: Our data suggests that hCTP inhibited NF-κB pathway transcriptional activity in response to TNF-α stimulation in a dose-dependent fashion in human CMCs. Furthermore, treatment with hCTP inhibited TNF-α induced IL-8 and IL-1β secretion even at doses as low as 1µM. The ability of hCTP to efficiently targeting this inflammatory pathway suggests that it has therapeutic potential in the treatment of heart failure. Further in vivo studies are ongoing to test this hypothesis.

Introduction: Heart failure with preserved ejection fraction (HFpEF) is a form of heart failure which is rapidly rising in incidence in the US today. Despite this, no therapies with mortality benefit exist for this syndrome. Previous work with our novel hybrid cardiac targeting peptide (hCTP), a cardiomyocyte-specific cell penetrating peptide, has shown multiple beneficial biological effects (improved calcium handling, anti-inflammatory properties) beyond its transduction abilities. Therefore, we hypothesized that treatment with hCTP in a mouse model of HFpEF would ameliorate the pathophysiology of this disease. Methods: To establish a HFpEF model, 6-week-old, C57BL/6NJ mice were placed on a high-fat diet (HFD), 60% kCal from lard, and water with 0.5 g/L of an iNOS inhibitor (N-Nitro-L-arginine methylester) to induce hypertension. After 5 weeks of the diet, HFD mice and their littermate controls underwent baseline exercise testing and echocardiograms. Exercise capacity was measured after 2 days of exercise training with 2 days of rest in between; mice were placed on a treadmill at a 10-degree angle and made to run at increasingly fast speeds (5-30 m/min) until exhaustion. Echocardiograms were performed under 1.5% inhalational isoflurane. After baseline testing, the mice were treated with vehicle, or either 2.5 or 5 mg/Kg hCTP, either 3 or 5 days a week (five groups, n = 3 per group). After four weeks of treatment, the mice were again subjected to the same battery of tests and euthanized. Data was compared using two way ANOVA with Sidak’s test to compare measurements pre- and post-treatment. Results: Treatment with hCTP at either concentration for five days/week led to an increase in running distance from 39.8 m to 116.3 m (p = 0.03, n = 6), compared to changes in control distance from 208.4 m to 157.8 m (p = 0.399). Running distance did not correlate with weight (R 2 < .001). Treatment with 5 mg/Kg hCTP for 5 days/week led to a normalization of the E/e’ ratio, from 43.3 to 26.9 (p = 0.004, n = 3) compared to a change in the control of 34.7 to 26.1 (p = 0.312). Ejection fractions remained consistent (>55%) across all groups. Conclusions: Our data suggests that hCTP appears to be a promising treatment in ameliorating some of the physiological effects in a murine model of HFpEF. Gene and protein expression studies in heart tissue are underway. Further work is warranted with a larger sample size.

Background: About one in five adults at age 40 will develop heart failure (HF) during their lifetime. Risk factors for HF (e.g., hypertension, etc.) alter cardiomyocytes structure and function resulting in HF. At the cellular level, these changes consist of mis/over-expression of genes that regulate cardiac identity (e.g., CamK2d, PKC, etc). The current paradigm for treating HF is pharmacological intervention or surgery; however, with few exceptions, the condition worsens with time. We are proposing a paradigm-shift for treating HF from a drug-centric system to a molecular approach that would reverse hypertrophy and adverse remodeling. Methods: A cardiac targeting peptide (CTP) was generated and linked by disulfide bond to miRNA106a, which was then introduced into a HF mouse model to measure its ability to reverse multiple heart failure parameters. CTP-miRNA106a was also introduced into a human cardiac cell line, followed by multiple analyses including Western Blot, qPCR, FACS, immunofluorescence all used to identify mechanism(s) utilized by CTP-miRNA106a to reverse HF characteristics. Results: Bio-distribution studies showed CTP delivered its miRNA106a cargo specifically to the heart within 30 mins, followed by clearance of CTP from the heart to the kidneys and liver by 3-5hrs post systemic drug injection. MiRNA106a persisted in cardiomyocytes until day 7 (latest tested time-point). CTP-miRNA106a reversed Ang2/Iso induced hypertrophy in 90% of the experimental mice ( Fig1 ). We also identified two potential HF intracellular signaling mechanisms (PLCb1/PKC/IP3 and NfkB) targeted by CTP-miRNA106a that could benefit both types of HF, HFrEF and HFpEF. PLCβ1 is a direct target for miRNA106a while the Nfkb pathway is indirectly targeted by decreased Camk2d (an miRNA106a target) signaling to IκBα. NfkB activity is quelled by miRNA106a. Conclusions: Our approach utilizes the function of miRNA106a to downregulate genes involved in cardiac hypertrophy and inflammation through the PLCb1 and CamKIId/Nfkb pathways. Most importantly, using a CTP-miRNA106a, we show delivery of miRNA106a cargo is specific to cardiomyocytes both in vitro and in vivo and that once delivered, many HF parameters including hypertrophy are reversed.

One of the bottlenecks to bringing new therapies to the clinic has been a lack of vectors for delivering novel therapeutics in a targeted manner. Cell penetrating peptides (CPPs) have received a lot of attention and have been the subject of numerous developments since their identification nearly three decades ago. Known for their transduction abilities, they have generally been considered inert vectors. In this review, we present a schema for their classification, highlight what is known about their mechanism of transduction, and outline the existing literature as well as our own experience, vis a vis the intrinsic anti-inflammatory properties that certain CPPs exhibit. Given the inflammatory responses associated with viral vectors, CPPs represent a viable alternative to such vectors; furthermore, the anti-inflammatory properties of CPPs, mostly through inhibition of the NF-κB pathway, are encouraging. Much more work in relevant animal models, toxicity studies in large animal models, and ultimately human trials are needed before their potential is fully realized.