Clonal Hematopoiesis and Risk of Progression of Heart Failure With Reduced Left Ventricular Ejection Fraction

Clonal Hematopoiesis Is Associated With Long-Term Adverse Outcomes Following Cardiac Surgery

BACKGROUND

Cardiac surgery triggers sterile innate immune responses leading to postoperative complications. Clonal hematopoiesis (CH) is associated with short-term inflammation-mediated outcomes after cardiac surgery. The impact of CH on long-term postoperative outcomes remains unknown.

METHODS AND RESULTS

In this cohort study, patients undergoing elective cardiac surgery were included from January 2017 to September 2019. Patients were screened for CH using a predefined gene panel of 19 genes. Recorded clinical events were all-cause death, major adverse cardiac and cerebral events including cardiovascular death, myocardial infarction or nonscheduled coronary revascularization, stroke, and hospitalization for acute heart failure. The primary study outcome was time to a composite criterion including all-cause mortality and major adverse cardiac and cerebral events. Among 314 genotyped patients (median age: 67 years; interquartile range 59-74 years), 139 (44%) presented with CH, based on a variant allelic frequency ≥1%. Carriers of CH had a higher proportion of patients with a history of atrial fibrillation (26% for CH versus 17% for non-CH carriers, P=0.022). The most frequently mutated genes were DNMT3A, TET2, and ASXL1. After a median follow-up of 1203 [813-1435] days, the primary outcome occurred in 50 patients. After multivariable adjustment, CH was independently associated with a higher risk for the primary outcome (hazard ratio, 1.88 [95% CI, 1.05-3.41], P=0.035). Most adverse events occurred in patients carrying TET2 variants.

CONCLUSIONS

In patients undergoing cardiac surgery, CH is frequent and associated with a 2-fold increased long-term risk for major adverse clinical outcomes. CH is a novel risk factor for long-term postcardiac surgery complications and might be useful to personalize management decisions.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT03376165.

Symptomatic Heart Failure and Clonal Hematopoiesis-Related Mutations in Patients With Acute Myeloid Leukemia

Clonal hematopoiesis of indeterminate potential (CHIP) is a common risk factor for hematologic malignancies and cardiovascular diseases. This study aimed to investigate the association between CHIP-related mutations and symptomatic heart failure (HF) in patients diagnosed with acute myeloid leukemia (AML). A total of 563 patients with newly diagnosed AML who underwent DNA sequencing of bone marrow before treatment were retrospectively investigated. Cox proportional hazard regression models and Fine and Gray's subdistribution hazard regression models were used to assess the association between CHIP-related mutations and symptomatic HF. A total of 79.0% patients had at least 1 CHIP-related mutation; the most frequent mutations were DNMT3A, ASXL1, and TET2. A total of 51 patients (9.1%) developed symptomatic HF. The incidence of symptomatic HF was more frequent in patients with DNMT3A mutations (p <0.01), with a 1-year cumulative incidence of symptomatic HF in patients with DNMT3A mutations of 11.4%, compared with 3.9% in patients with wild-type DNMT3A (p <0.01). After adjustment for age and anthracyclines dose, DNMT3A mutations remained independently correlated with HF (hazard ratio 2.32, 95% confidence interval 1.26 to 4.29, p = 0.01). In conclusion, in patients with AML, the presence of DNMT3A mutations was associated with a twofold increased risk for symptomatic HF, irrespective of age and anthracyclines use.

Interplay of the heart, spleen, and bone marrow in heart failure: the role of splenic extramedullary hematopoiesis

Improvements in therapies for heart failure with preserved ejection fraction (HFpEF) are crucial for improving patient outcomes and quality of life. Although HFpEF is the predominant heart failure type among older individuals, its prognosis is often poor owing to the lack of effective therapies. The roles of the spleen and bone marrow are often overlooked in the context of HFpEF. Recent studies suggest that the spleen and bone marrow could play key roles in HFpEF, especially in relation to inflammation and immune responses. The bone marrow can increase production of certain immune cells that can migrate to the heart and contribute to disease. The spleen can contribute to immune responses that either protect or exacerbate heart failure. Extramedullary hematopoiesis in the spleen could play a crucial role in HFpEF. Increased metabolic activity in the spleen, immune cell production and mobilization to the heart, and concomitant cytokine production may occur in heart failure. This leads to systemic chronic inflammation, along with an imbalance of immune cells (macrophages) in the heart, resulting in chronic inflammation and progressive fibrosis, potentially leading to decreased cardiac function. The bone marrow and spleen are involved in altered iron metabolism and anemia, which also contribute to HFpEF. This review presents the concept of an interplay between the heart, spleen, and bone marrow in the setting of HFpEF, with a particular focus on extramedullary hematopoiesis in the spleen. The aim of this review is to discern whether the spleen can serve as a new therapeutic target for HFpEF.

Colchicine prevents accelerated atherosclerosis in TET2-mutant clonal haematopoiesis

BACKGROUND AND AIMS

Somatic mutations in the TET2 gene that lead to clonal haematopoiesis (CH) are associated with accelerated atherosclerosis development in mice and a higher risk of atherosclerotic disease in humans. Mechanistically, these observations have been linked to exacerbated vascular inflammation. This study aimed to evaluate whether colchicine, a widely available and inexpensive anti-inflammatory drug, prevents the accelerated atherosclerosis associated with TET2-mutant CH.

METHODS

In mice, TET2-mutant CH was modelled using bone marrow transplantations in atherosclerosis-prone Ldlr-/- mice. Haematopoietic chimeras carrying initially 10% Tet2-/- haematopoietic cells were fed a high-cholesterol diet and treated with colchicine or placebo. In humans, whole-exome sequencing data and clinical data from 37 181 participants in the Mass General Brigham Biobank and 437 236 participants in the UK Biobank were analysed to examine the potential modifying effect of colchicine prescription on the relationship between CH and myocardial infarction.

RESULTS

Colchicine prevented accelerated atherosclerosis development in the mouse model of TET2-mutant CH, in parallel with suppression of interleukin-1β overproduction in conditions of TET2 loss of function. In humans, patients who were prescribed colchicine had attenuated associations between TET2 mutations and myocardial infarction. This interaction was not observed for other mutated genes.

CONCLUSIONS

These results highlight the potential value of colchicine to mitigate the higher cardiovascular risk of carriers of somatic TET2 mutations in blood cells. These observations set the basis for the development of clinical trials that evaluate the efficacy of precision medicine approaches tailored to the effects of specific mutations linked to CH.

Unidirectional association of clonal hematopoiesis with atherosclerosis development

Clonal hematopoiesis, a condition in which acquired somatic mutations in hematopoietic stem cells lead to the outgrowth of a mutant hematopoietic clone, is associated with a higher risk of hematological cancer and a growing list of nonhematological disorders, most notably atherosclerosis and associated cardiovascular disease. However, whether accelerated atherosclerosis is a cause or a consequence of clonal hematopoiesis remains a matter of debate. Some studies support a direct contribution of certain clonal hematopoiesis-related mutations to atherosclerosis via exacerbation of inflammatory responses, whereas others suggest that clonal hematopoiesis is a symptom rather than a cause of atherosclerosis, as atherosclerosis or related traits may accelerate the expansion of mutant hematopoietic clones. Here we combine high-sensitivity DNA sequencing in blood and noninvasive vascular imaging to investigate the interplay between clonal hematopoiesis and atherosclerosis in a longitudinal cohort of healthy middle-aged individuals. We found that the presence of a clonal hematopoiesis-related mutation confers an increased risk of developing de novo femoral atherosclerosis over a 6-year period, whereas neither the presence nor the extent of atherosclerosis affects mutant cell expansion during this timeframe. These findings indicate that clonal hematopoiesis unidirectionally promotes atherosclerosis, which should help translate the growing understanding of this condition into strategies for the prevention of atherosclerotic cardiovascular disease in individuals exhibiting clonal hematopoiesis.

Cardiovascular Risk in Philadelphia-Negative Myeloproliferative Neoplasms: Mechanisms and Implications-A Narrative Review

Myeloproliferative neoplasms (MPNs), encompassing disorders like polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF), are characterized by clonal hematopoiesis without the Philadelphia chromosome. The JAK2 V617F mutation is prevalent in PV, ET, and PMF, while mutations in MPL and CALR also play significant roles. These conditions predispose patients to thrombotic events, with PMF exhibiting the lowest survival among MPNs. Chronic inflammation, driven by cytokine release from aberrant leukocytes and platelets, amplifies cardiovascular risk through various mechanisms, including atherosclerosis and vascular remodeling. Additionally, MPN-related complications like pulmonary hypertension and cardiac fibrosis contribute to cardiovascular morbidity and mortality. This review consolidates recent research on MPNs' cardiovascular implications, emphasizing thrombotic risk, chronic inflammation, and vascular stiffness. Understanding these associations is crucial for developing targeted therapies and improving outcomes in MPN patients.

Clonal haematopoiesis is associated with major adverse cardiovascular events in patients with hypertrophic cardiomyopathy

AIMS

The heterogeneous phenotype of hypertrophic cardiomyopathy (HCM) is still not fully understood. Clonal haematopoiesis (CH) is emerging as a cardiovascular risk factor potentially associated with adverse clinical events. The prevalence, phenotype and outcomes related to CH in HCM patients were evaluated.

METHODS AND RESULTS

Patients with HCM and available biospecimens from the Peter Munk Cardiac Centre Cardiovascular Biobank were subjected to targeted sequencing for 35 myeloid genes associated with CH. CH prevalence, clinical characteristics, morphological phenotypes assessed by echocardiogram and cardiac magnetic resonance and outcomes were assessed. All patients were evaluated for a 71-plex cytokines/chemokines, troponin I and B-type natriuretic peptide analysis. Major adverse cardiovascular events (MACE) were defined as appropriate implantable cardioverter-defibrillator shock, stroke, cardiac arrest, orthotopic heart transplant and death. Among the 799 patients, CH was found in 183 (22.9%) HCM patients with sarcomeric germline mutations. HCM patients with CH were more symptomatic and with a higher burden of fibrosis than those without CH. CH was associated with MACE in those HCM patients with sarcomeric germline mutations (adjusted hazard ratio [HR] 6.89, 95% confidence interval [CI] 1.78-26.6; p = 0.005), with the highest risk among those that had DNMT3A, TET2 and ASXL1 mutations (adjusted HR 5.76, 95% CI 1.51-21.94; p = 0.010). Several cytokines (IL-1ra, IL-6, IL-17F, TGFα, CCL21, CCL1, CCL8, and CCL17), and troponin I were upregulated in gene-positive HCM patients with CH.

CONCLUSIONS

These results indicate that CH in patients with HCM is associated with worse clinical outcomes. In the absence of CH, gene-positive patients with HCM have lower rates of MACE.

Association Between Clonal Hematopoiesis and Left Ventricular Reverse Remodeling in Nonischemic Dilated Cardiomyopathy

Although clonal hematopoiesis of indeterminate potential (CHIP) is an adverse prognostic factor for atherosclerotic disease, its impact on nonischemic dilated cardiomyopathy (DCM) is elusive. The authors performed whole-exome sequencing and deep target sequencing among 198 patients with DCM and detected germline mutations in cardiomyopathy-related genes and somatic mutations in CHIP driver genes. Twenty-five CHIP driver mutations were detected in 22 patients with DCM. Ninety-two patients had cardiomyopathy-related pathogenic mutations. Multivariable analysis revealed that CHIP was an independent risk factor of left ventricular reverse remodeling, irrespective of known prognostic factors. CHIP exacerbated cardiac systolic dysfunction and fibrosis in a DCM murine model. The identification of germline and somatic mutations in patients with DCM predicts clinical prognosis.

Clinical and Therapeutic Implications of Clonal Hematopoiesis

Clonal hematopoiesis (CH) is an age-related process whereby hematopoietic stem and progenitor cells (HSPCs) acquire mutations that lead to a proliferative advantage and clonal expansion. The most commonly mutated genes are epigenetic regulators, DNA damage response genes, and splicing factors, which are essential to maintain functional HSPCs and are frequently involved in the development of hematologic malignancies. Established risk factors for CH, including age, prior cytotoxic therapy, and smoking, increase the risk of acquiring CH and/or may increase CH fitness. CH has emerged as a novel risk factor in many age-related diseases, such as hematologic malignancies, cardiovascular disease, diabetes, and autoimmune disorders, among others. Future characterization of the mechanisms driving CH evolution will be critical to develop preventative and therapeutic approaches.

Clonal hematopoiesis of indeterminate potential as a prognostic factor: a systematic review and meta-analysis

ABSTRACT

With advances in sequencing, individuals with clonal hematopoiesis of indeterminate potential (CHIP) are increasingly being identified, making it essential to understand its prognostic implications. We conducted a systematic review of studies comparing the risk of clinical outcomes in individuals with and without CHIP. We searched MEDLINE and EMBASE and included original research reporting an outcome risk measure in individuals with CHIP, adjusted for the effect of age. From the 3305 studies screened, we included 88 studies with 45 to 470 960 participants. Most studies had a low-to-moderate risk of bias in all domains of the Quality in Prognostic Factor Studies tool. Random-effects meta-analyses were performed for outcomes reported in at least 3 studies. CHIP conferred an increased risk of all-cause mortality (hazard ratio [HR], 1.34; 95% confidence interval, 1.19-1.50), cancer mortality (HR, 1.46; 1.13-1.88), composite cardiovascular events (HR, 1.40; 1.19-1.65), coronary heart disease (HR, 1.76; 1.27-2.44), stroke (HR, 1.16; 1.05-1.28), heart failure (HR, 1.27; 1.15-1.41), hematologic malignancy (HR, 4.28; 2.29-7.98), lung cancer (HR, 1.40; 1.27-1.54), renal impairment (HR, 1.25; 1.18-1.33) and severe COVID-19 (odds ratio [OR], 1.46; 1.18-1.80). CHIP was not associated with cardiovascular mortality (HR, 1.09; 0.97-1.22), except in the subgroup analysis restricted to larger clones (HR, 1.31; 1.12-1.54). Isolated DNMT3A mutations did not increase the risk of myeloid malignancy, all-cause mortality, or renal impairment. The reasons for heterogeneity between studies included differences in definitions and measurements of CHIP and the outcomes, and populations studied. In summary, CHIP is associated with diverse clinical outcomes, with clone size, specific gene, and inherent patient characteristics important mediators of risk.

Systemic aging fuels heart failure: Molecular mechanisms and therapeutic avenues

Systemic aging influences various physiological processes and contributes to structural and functional decline in cardiac tissue. These alterations include an increased incidence of left ventricular hypertrophy, a decline in left ventricular diastolic function, left atrial dilation, atrial fibrillation, myocardial fibrosis and cardiac amyloidosis, elevating susceptibility to chronic heart failure (HF) in the elderly. Age-related cardiac dysfunction stems from prolonged exposure to genomic, epigenetic, oxidative, autophagic, inflammatory and regenerative stresses, along with the accumulation of senescent cells. Concurrently, age-related structural and functional changes in the vascular system, attributed to endothelial dysfunction, arterial stiffness, impaired angiogenesis, oxidative stress and inflammation, impose additional strain on the heart. Dysregulated mechanosignalling and impaired nitric oxide signalling play critical roles in the age-related vascular dysfunction associated with HF. Metabolic aging drives intricate shifts in glucose and lipid metabolism, leading to insulin resistance, mitochondrial dysfunction and lipid accumulation within cardiomyocytes. These alterations contribute to cardiac hypertrophy, fibrosis and impaired contractility, ultimately propelling HF. Systemic low-grade chronic inflammation, in conjunction with the senescence-associated secretory phenotype, aggravates cardiac dysfunction with age by promoting immune cell infiltration into the myocardium, fostering HF. This is further exacerbated by age-related comorbidities like coronary artery disease (CAD), atherosclerosis, hypertension, obesity, diabetes and chronic kidney disease (CKD). CAD and atherosclerosis induce myocardial ischaemia and adverse remodelling, while hypertension contributes to cardiac hypertrophy and fibrosis. Obesity-associated insulin resistance, inflammation and dyslipidaemia create a profibrotic cardiac environment, whereas diabetes-related metabolic disturbances further impair cardiac function. CKD-related fluid overload, electrolyte imbalances and uraemic toxins exacerbate HF through systemic inflammation and neurohormonal renin-angiotensin-aldosterone system (RAAS) activation. Recognizing aging as a modifiable process has opened avenues to target systemic aging in HF through both lifestyle interventions and therapeutics. Exercise, known for its antioxidant effects, can partly reverse pathological cardiac remodelling in the elderly by countering processes linked to age-related chronic HF, such as mitochondrial dysfunction, inflammation, senescence and declining cardiomyocyte regeneration. Dietary interventions such as plant-based and ketogenic diets, caloric restriction and macronutrient supplementation are instrumental in maintaining energy balance, reducing adiposity and addressing micronutrient and macronutrient imbalances associated with age-related HF. Therapeutic advancements targeting systemic aging in HF are underway. Key approaches include senomorphics and senolytics to limit senescence, antioxidants targeting mitochondrial stress, anti-inflammatory drugs like interleukin (IL)-1β inhibitors, metabolic rejuvenators such as nicotinamide riboside, resveratrol and sirtuin (SIRT) activators and autophagy enhancers like metformin and sodium-glucose cotransporter 2 (SGLT2) inhibitors, all of which offer potential for preserving cardiac function and alleviating the age-related HF burden.

Heart failure promotes multimorbidity through innate immune memory

Patients with heart failure (HF) often experience repeated acute decompensation and develop comorbidities such as chronic kidney disease and frailty syndrome. Although this suggests pathological interaction among comorbidities, the mechanisms linking them are poorly understood. Here, we identified alterations in hematopoietic stem cells (HSCs) as a critical driver of recurrent HF and associated comorbidities. Bone marrow transplantation from HF-experienced mice resulted in spontaneous cardiac dysfunction and fibrosis in recipient mice, as well as increased vulnerability to kidney and skeletal muscle insults. HF enhanced the capacity of HSCs to generate proinflammatory macrophages. In HF mice, global chromatin accessibility analysis and single-cell RNA-seq showed that transforming growth factor-β (TGF-β) signaling was suppressed in HSCs, which corresponded with repressed sympathetic nervous activity in bone marrow. Transplantation of bone marrow from mice in which TGF-β signaling was inhibited similarly exacerbated cardiac dysfunction. Collectively, these results suggest that cardiac stress modulates the epigenome of HSCs, which in turn alters their capacity to generate cardiac macrophage subpopulations. This change in HSCs may be a common driver of repeated HF events and comorbidity by serving as a key carrier of "stress memory."

Clonal Hematopoiesis of Indeterminate Potential With Loss of Tet2 Enhances Risk for Atrial Fibrillation Through Nlrp3 Inflammasome Activation

BACKGROUND

Clonal hematopoiesis of indeterminate potential (CHIP), a common age-associated phenomenon, associates with increased risk of both hematological malignancy and cardiovascular disease. Although CHIP is known to increase the risk of myocardial infarction and heart failure, the influence of CHIP in cardiac arrhythmias, such as atrial fibrillation (AF), is less explored.

METHODS

CHIP prevalence was determined in the UK Biobank, and incident AF analysis was stratified by CHIP status and clone size using Cox proportional hazard models. Lethally irradiated mice were transplanted with hematopoietic-specific loss of Tet2, hematopoietic-specific loss of Tet2 and Nlrp3, or wild-type control and fed a Western diet, compounded with or without NLRP3 (NLR [NACHT, LRR {leucine rich repeat}] family pyrin domain containing protein 3) inhibitor, NP3-361, for 6 to 9 weeks. Mice underwent in vivo invasive electrophysiology studies and ex vivo optical mapping. Cardiomyocytes from Ldlr-/- mice with hematopoietic-specific loss of Tet2 or wild-type control and fed a Western diet were isolated to evaluate calcium signaling dynamics and analysis. Cocultures of pluripotent stem cell-derived atrial cardiomyocytes were incubated with Tet2-deficient bone marrow-derived macrophages, wild-type control, or cytokines IL-1β (interleukin 1β) or IL-6 (interleukin 6).

RESULTS

Analysis of the UK Biobank showed individuals with CHIP, in particular TET2 CHIP, have increased incident AF. Hematopoietic-specific inactivation of Tet2 increases AF propensity in atherogenic and nonatherogenic mouse models and is associated with increased Nlrp3 expression and CaMKII (Ca2+/calmodulin-dependent protein kinase II) activation, with AF susceptibility prevented by inactivation of Nlrp3. Cardiomyocytes isolated from Ldlr-/- mice with hematopoietic inactivation of Tet2 and fed a Western diet have impaired calcium release from the sarcoplasmic reticulum into the cytosol, contributing to atrial arrhythmogenesis. Abnormal sarcoplasmic reticulum calcium release was recapitulated in cocultures of cardiomyocytes with the addition of Tet2-deficient macrophages or cytokines IL-1β or IL-6.

CONCLUSIONS

We identified a modest association between CHIP, particularly TET2 CHIP, and incident AF in the UK Biobank population. In a mouse model of AF resulting from hematopoietic-specific inactivation of Tet2, we propose altered calcium handling as an arrhythmogenic mechanism, dependent on Nlrp3 inflammasome activation. Our data are in keeping with previous studies of CHIP in cardiovascular disease, and further studies into the therapeutic potential of NLRP3 inhibition for individuals with TET2 CHIP may be warranted.

Clonal hematopoiesis is associated with cardiovascular events in patients with stable coronary artery disease

Clonal hematopoiesis (CH) is a risk factor for atherosclerotic cardiovascular disease, but the impact of smaller clones and the effect on inflammatory parameters is largely unknown. Using ultrasensitive single-molecule molecular inversion probe sequencing, we evaluated the association between CH and a first major adverse cardiovascular event (MACE) in patients with angiographically documented stable coronary artery disease (CAD) and no history of acute ischemic events. CH was associated with an increased rate of MACE at four years follow-up. The size of the clone predicted MACE at an optimal cut-off value of 1.07% variant allele frequency (VAF). Mutation carriers had no change in monocytes subsets or cytokine production capacity but had higher levels of circulating tissue factor, matrilysin, and proteinase-activated receptor-1. Our study identified CH driver mutations with a VAF as small as 1.07% as a residual cardiovascular risk factor and identified potential biomarkers and therapeutic targets for patients with stable CAD.

Clonal haematopoiesis of indeterminate potential and atrial fibrillation: an east Asian cohort study

BACKGROUND AND AIMS

Both clonal haematopoiesis of indeterminate potential (CHIP) and atrial fibrillation (AF) are age-related conditions. This study investigated the potential role of CHIP in the development and progression of AF.

METHODS

Deep-targeted sequencing of 24 CHIP mutations (a mean depth of coverage = 1000×) was performed in 1004 patients with AF and 3341 non-AF healthy subjects. Variant allele fraction ≥ 2.0% indicated the presence of CHIP mutations. The association between CHIP and AF was evaluated by the comparison of (i) the prevalence of CHIP mutations between AF and non-AF subjects and (ii) clinical characteristics discriminated by CHIP mutations within AF patients. Furthermore, the risk of clinical outcomes-the composite of heart failure, ischaemic stroke, or death-according to the presence of CHIP mutations in AF was investigated from the UK Biobank cohort.

RESULTS

The mean age was 67.6 ± 6.9 vs. 58.5 ± 6.5 years in AF (paroxysmal, 39.0%; persistent, 61.0%) and non-AF cohorts, respectively. CHIP mutations with a variant allele fraction of ≥2.0% were found in 237 (23.6%) AF patients (DNMT3A, 13.5%; TET2, 6.6%; and ASXL1, 1.5%) and were more prevalent than non-AF subjects [356 (10.7%); P < .001] across the age. After multivariable adjustment (age, sex, smoking, body mass index, diabetes, and hypertension), CHIP mutations were 1.4-fold higher in AF [adjusted odds ratio (OR) 1.38; 95% confidence interval 1.10-1.74, P < .01]. The ORs of CHIP mutations were the highest in the long-standing persistent AF (adjusted OR 1.50; 95% confidence interval 1.14-1.99, P = .004) followed by persistent (adjusted OR 1.44) and paroxysmal (adjusted OR 1.33) AF. In gene-specific analyses, TET2 somatic mutation presented the highest association with AF (adjusted OR 1.65; 95% confidence interval 1.05-2.60, P = .030). AF patients with CHIP mutations were older and had a higher prevalence of diabetes, a longer AF duration, a higher E/E', and a more severely enlarged left atrium than those without CHIP mutations (all P < .05). In UK Biobank analysis of 21 286 AF subjects (1297 with CHIP and 19 989 without CHIP), the CHIP mutation in AF is associated with a 1.32-fold higher risk of a composite clinical event (heart failure, ischaemic stroke, or death).

CONCLUSIONS

CHIP mutations, primarily DNMT3A or TET2, are more prevalent in patients with AF than non-AF subjects whilst their presence is associated with a more progressive nature of AF and unfavourable clinical outcomes.

[Heart and blood: clonal hematopoiesis]

Cardiovascular diseases are among the leading causes of death worldwide, with well-known modifiable risk factors, such as smoking, overweight, lipid metabolism disorders, lack of physical activity and high blood pressure playing a significant role. Recent studies have now identified "clonal hematopoiesis" as a novel blood-based risk factor. Clonal hematopoiesis arises from mutations in hematopoietic stem cells, which lead to the expansion of mutated blood cells. Mutated cell clones can be detected in over 40% of individuals over 50 years old, with more than 15% of those over 90 years old harboring large clones. Surprisingly, mutated cells predispose to the development of leukemia only to a minor extent, leading to the term clonal hematopoiesis of indeterminate potential (CHIP); however, it has been shown that CHIP is associated with an increased risk of cardiovascular diseases. Individuals with CHIP-associated gene mutations have an elevated risk of atherosclerotic vascular diseases, stroke and thrombosis. Patients with heart failure with reduced ejection fraction (HFrEF), whether of ischemic or non-ischemic origin and patients with heart failure with preserved ejection fraction (HFpEF) exhibit an increased number of mutated cells in the blood. The presence of CHIP mutations is linked to a poorer prognosis in patients with existing cardiovascular diseases. Future research should aim at a better understanding of the specific effects of different mutations, clone sizes and combinations to develop personalized therapeutic approaches. Various anti-inflammatory therapeutic drugs are available, which can be tested in controlled studies.

Somatic and Germline Variants and Coronary Heart Disease in a Chinese Population

Importance

The genetic basis of coronary heart disease (CHD) has expanded from a germline to somatic genome, including clonal hematopoiesis of indeterminate potential (CHIP). How CHIP confers CHD risk in East Asian individuals, especially those with small clones (variant allele fraction [VAF] 0.5%-2%) and different genetic backgrounds, was completely unknown.

Objective

To investigate the CHIP profile in a general Chinese cohort by deep sequencing and further explore the association between CHIP and incident CHD considering germline predisposition.

Design, Setting, and Participants

This cohort study used data from 3 prospective cohorts in the project Prediction for Atherosclerotic Cardiovascular Disease Risk in China. Participants without cardiovascular disease or cancer at baseline were enrolled in 2001 and 2008 and had a median follow-up of 12.17 years extending into 2021.

Exposures

CHIP mutations were detected by targeted sequencing (mean depth, 916×). A predefined CHD polygenic risk score (PRS) comprising 531 variants was used to evaluate germline predisposition.

Main Outcomes and Measures

The main outcome was first incident CHD.

Results

Among 6181 participants, the median (IQR) age was 53.83 years (45.35-62.39 years); 3082 participants (49.9%) were female, and 3099 (50.1%) were male. A total of 1100 individuals (17.80%) harbored 1372 CHIP mutations at baseline. CHIP was independently associated with incident CHD (hazard ratio [HR], 1.42; 95% CI, 1.18-1.72; P = 2.82 × 10-4) and presented a risk gradient with increasing VAF (P = 3.98 × 10-3 for trend). Notably, individuals with small clones, nearly half of CHIP carriers, also demonstrated a higher CHD risk compared with non-CHIP carriers (HR, 1.33; 95% CI, 1.02-1.74; P = .03) and were 4 years younger than those with VAF of 2% or greater (median age, 58.52 vs 62.70 years). Heightened CHD risk was not observed among CHIP carriers with low PRS (HR, 1.02; 95% CI, 0.64-1.64; P = .92), while high PRS and CHIP jointly contributed a 2.23-fold increase in risk (95% CI, 1.51-3.29; P = 6.29 × 10-5) compared with non-CHIP carriers with low PRS. Interestingly, the diversity in CHIP-related CHD risk within each PRS group was substantially diminished when removing variants in the inflammatory pathway from the PRS.

Conclusions

This study revealed that elevated CHD risk attributed to CHIP was nonnegligible even for small clones. Inflammation genes involved in CHD could aggravate or abrogate CHIP-related CHD risk.

Clonal haematopoiesis, ageing and kidney disease

Clonal haematopoiesis of indeterminate potential (CHIP) is a preclinical condition wherein a sizeable proportion of an individual's circulating blood cells are derived from a single mutated haematopoietic stem cell. CHIP occurs frequently with ageing - more than 10% of individuals over 65 years of age are affected - and is associated with an increased risk of disease across several organ systems and premature death. Emerging evidence suggests that CHIP has a role in kidney health, including associations with predisposition to acute kidney injury, impaired recovery from acute kidney injury and kidney function decline, both in the general population and among those with chronic kidney disease. Beyond its direct effect on the kidney, CHIP elevates the susceptibility of individuals to various conditions that can detrimentally affect the kidneys, including cardiovascular disease, obesity and insulin resistance, liver disease, gout, osteoporosis and certain autoimmune diseases. Aberrant pro-inflammatory signalling, telomere attrition and epigenetic ageing are potential causal pathophysiological pathways and mediators that underlie CHIP-related disease risk. Experimental animal models have shown that inhibition of inflammatory cytokine signalling can ameliorate many of the pathological effects of CHIP, and assessment of the efficacy and safety of this class of medications for human CHIP-associated pathology is ongoing.

TET2 mutation as prototypic clonal hematopoiesis lesion

Loss of function TET2 mutation (TET2MT) is one of the most frequently observed lesions in clonal hematopoiesis (CH). TET2 a member TET-dioxygenase family of enzymes that along with TET1 and TET3, progressively oxidize 5-methyl cytosine (mC) resulting in regulated demethylation of promoter, enhancer and silencer elements of the genome. This process is critical for efficient transcription that determine cell lineage fate, proliferation and survival and the maintenance of the genomic fidelity with aging of the organism. Partial or complete loss-of-function TET2 mutations create regional and contextual DNA hypermethylation leading to gene silencing or activation that result in skewed myeloid differentiation and clonal expansion. In addition to myeloid skewing, loss of TET2 creates differentiation block and provides proliferative advantage to hematopoietic stem and progenitor cells (HSPCs). TET2MT is a prototypical lesion in CH, since the mutant clones dominate during stress hematopoiesis and often associates with evolution of myeloid malignancies. TET2MT clones has unique privilege to create and persist in pro-inflammatory milieu. Despite extensive knowledge regarding biochemical mechanisms underlying distorted myeloid differentiation, and enhanced self-replication of TET2MT HSPC, the mechanistic link of various pathogenesis associated with TET2 loss in CHIP is less understood. Here we review the recent development in TET2 biology and its probable mechanistic link in CH with aging and inflammation. We also explored the therapeutic strategies of targeting TET2MT associated CHIP and the utility of targeting TET2 in normal hematopoiesis and somatic cell reprograming. We explore the biochemical mechanisms and candidate therapies that emerged in last decade of research.

Clonal Hematopoiesis of Indeterminate Potential in Chronic Thromboembolic Pulmonary Hypertension: A Multicenter Study

BACKGROUND

The pathogenesis of chronic thromboembolic pulmonary hypertension (CTEPH) is multifactorial and growing evidence has indicated that hematological disorders are involved. Clonal hematopoiesis of indeterminate potential (CHIP) has recently been associated with an increased risk of both hematological malignancies and cardiovascular diseases. However, the prevalence and clinical relevance of CHIP in patients with CTEPH remains unclear.

METHODS

Using stepwise calling on next-generation sequencing data from 499 patients with CTEPH referred to 3 centers between October 2006 and December 2021, CHIP mutations were identified. We associated CHIP with all-cause mortality in patients with CTEPH. To provide insights into potential mechanisms, the associations between CHIP and inflammatory markers were also determined.

RESULTS

In total, 47 (9.4%) patients with CTEPH carried at least 1 CHIP mutation at a variant allele frequency of ≥2%. The most common mutations were in DNMT3A, TET2, RUNX1, and ASXL1. During follow-up (mean, 55 months), deaths occurred in 22 (46.8%) and 104 (23.0%) patients in the CHIP and non-CHIP groups, respectively (P<0.001, log-rank test). The association of CHIP with mortality remained robust in the fully adjusted model (hazard ratio, 2.190 [95% CI, 1.257-3.816]; P=0.006). Moreover, patients with CHIP mutations showed higher circulating interleukin-1β and interleukin-6 and lower interleukin-4 and IgG galactosylation levels.

CONCLUSIONS

This is the first study to show that CHIP mutations occurred in 9.4% of patients with CTEPH are associated with a severe inflammatory state and confer a poorer prognosis in long-term follow-up.

DNMT3A clonal hematopoiesis-driver mutations induce cardiac fibrosis by paracrine activation of fibroblasts

Hematopoietic mutations in epigenetic regulators like DNA methyltransferase 3 alpha (DNMT3A), play a pivotal role in driving clonal hematopoiesis of indeterminate potential (CHIP), and are associated with unfavorable outcomes in patients suffering from heart failure (HF). However, the precise interactions between CHIP-mutated cells and other cardiac cell types remain unknown. Here, we identify fibroblasts as potential partners in interactions with CHIP-mutated monocytes. We used combined transcriptomic data derived from peripheral blood mononuclear cells of HF patients, both with and without CHIP, and cardiac tissue. We demonstrate that inactivation of DNMT3A in macrophages intensifies interactions with cardiac fibroblasts and increases cardiac fibrosis. DNMT3A inactivation amplifies the release of heparin-binding epidermal growth factor-like growth factor, thereby facilitating activation of cardiac fibroblasts. These findings identify a potential pathway of DNMT3A CHIP-driver mutations to the initiation and progression of HF and may also provide a compelling basis for the development of innovative anti-fibrotic strategies.

Clonal hematopoiesis of indeterminate potential-associated non-small cell lung cancer risk is potentiated by small particulate matter air pollution among non-smokers: a novel somatic variant-environment interaction

Small particulate matter air pollution (PM 2.5 ) is a recognized driver of non-small cell lung cancer (NSCLC) among non-smoking individuals. Inhaled PM 2.5 recruits pro-inflammatory macrophages to the air-lung interface, which promotes malignant lung epithelial cell growth and progression to overt cancer. We sought to determine whether clonal hematopoiesis of indeterminate potential (CHIP), a common age-related condition characterized by hyperinflammatory macrophages, exacerbates PM 2.5 -associated NSCLC in non-smokers using genetic, environmental, and phenotypic data from 413,901 individuals in the UK Biobank. Among non-smokers, PM 2.5 is not associated with NSCLC and not associated with prevalence of CHIP, but CHIP is associated with a doubling of NSCLC risk (hazard ratio (HR) 2.01, 95% confidence interval (CI): 1.34-3.00). Moreover, CHIP-associated NSCLC risk is exacerbated in the setting of above-median PM 2.5 levels (HR 2.70, 95% CI: 1.60-4.55). PM 2.5 × CHIP is also associated with significantly greater markers of systemic inflammation (CRP, IL-6, and IL-1β) than expected. Altogether, these results suggest CHIP and PM 2.5 form a novel gene × environment interaction promoting NSCLC tumorigenesis in non-smokers.

Clonal Expansion in Cardiovascular Pathology

Clonal expansion refers to the proliferation and selection of advantageous "clones" that are better suited for survival in a Darwinian manner. In recent years, we have greatly enhanced our understanding of cell clonality in the cardiovascular context. However, our knowledge of the underlying mechanisms behind this clonal selection is still severely limited. There is a transpiring pattern of clonal expansion of smooth muscle cells and endothelial cells-and, in some cases, macrophages-in numerous cardiovascular diseases irrespective of their differing microenvironments. These findings indirectly suggest the possible existence of stem-like vascular cells which are primed to respond during disease. Subsequent clones may undergo further phenotypic changes to adopt either protective or detrimental roles. By investigating these clone-forming vascular cells, we may be able to harness this inherent clonal nature for future therapeutic intervention. This review comprehensively discusses what is currently known about clonal expansion across the cardiovascular field. Comparisons of the clonal nature of vascular cells in atherosclerosis (including clonal hematopoiesis of indeterminate potential), pulmonary hypertension, aneurysm, blood vessel injury, ischemia- and tumor-induced angiogenesis, and cerebral cavernous malformations are evaluated. Finally, we discuss the potential clinical implications of these findings and propose that proper understanding and specific targeting of these clonal cells may provide unique therapeutic options for the treatment of these cardiovascular conditions.

Clonal hematopoiesis of indeterminate potential: implications for the cardiologists

Myeloproliferative neoplasms, including polycythemia vera, essential thrombocythemia, and myelofibrosis, are characterized by somatic gene mutations in bone marrow stem cells, which trigger an inflammatory response influencing the development of associated cardiovascular complications. In recent years, the same mutations were found in individuals with cardiovascular diseases even in the absence of hematological alterations. These genetic events allow the identification of a new entity called 'clonal hematopoiesis of indeterminate potential' (CHIP), as it was uncertain whether it could evolve toward hematological malignancies. CHIP is age-related and, remarkably, myocardial infarction, stroke, and heart failure were frequently reported in these individuals and attributed to systemic chronic inflammation driven by the genetic mutation. We reviewed the connection between clonal hematopoiesis, inflammation, and cardiovascular diseases, with a practical approach to improve clinical practice and highlight the current unmet needs in this area of knowledge.

Regulators of clonal hematopoiesis and physiological consequences of this condition

Clonal hematopoiesis (CH) is a prevalent condition that results from somatic mutations in hematopoietic stem cells. When these mutations occur in "driver" genes, they can potentially confer fitness advantages to the affected cells, leading to a clonal expansion. While most clonal expansions of mutant cells are generally considered to be asymptomatic since they do not impact overall blood cell numbers, CH carriers face long-term risks of all-cause mortality and age-associated diseases, including cardiovascular disease and hematological malignancies. While considerable research has focused on understanding the association between CH and these diseases, less attention has been given to exploring the regulatory factors that contribute to the expansion of the driver gene clone. This review focuses on the association between environmental stressors and inherited genetic risk factors in the context of CH development. A better understanding of how these stressors impact CH development will facilitate mechanistic studies and potentially lead to new therapeutic avenues to treat individuals with this condition.

Molecular and clinical aspects relevant for counseling individuals with clonal hematopoiesis of indeterminate potential

Clonal hematopoiesis of indeterminate potential (CHIP) has fascinated the medical community for some time. Discovered about a decade ago, this phenomenon links age-related alterations in hematopoiesis not only to the later development of hematological malignancies but also to an increased risk of early-onset cardiovascular disease and some other disorders. CHIP is detected in the blood and is characterized by clonally expanded somatic mutations in cancer-associated genes, predisposing to the development of hematologic neoplasms such as MDS and AML. CHIP-associated mutations often involve DNA damage repair genes and are frequently observed following prior cytotoxic cancer therapy. Genetic predisposition seems to be a contributing factor. It came as a surprise that CHIP significantly elevates the risk of myocardial infarction and stroke, and also contributes to heart failure and pulmonary hypertension. Meanwhile, evidence of mutant clonal macrophages in vessel walls and organ parenchyma helps to explain the pathophysiology. Besides aging, there are some risk factors promoting the appearance of CHIP, such as smoking, chronic inflammation, chronic sleep deprivation, and high birth weight. This article describes fundamental aspects of CHIP and explains its association with hematologic malignancies, cardiovascular disorders, and other medical conditions, while also exploring potential progress in the clinical management of affected individuals. While it is important to diagnose conditions that can lead to adverse, but potentially preventable, effects, it is equally important not to stress patients by confronting them with disconcerting findings that cannot be remedied. Individuals with diagnosed or suspected CHIP should receive counseling in a specialized outpatient clinic, where professionals from relevant medical specialties may help them to avoid the development of CHIP-related health problems. Unfortunately, useful treatments and clinical guidelines for managing CHIP are still largely lacking. However, there are some promising approaches regarding the management of cardiovascular disease risk. In the future, strategies aimed at restoration of gene function or inhibition of inflammatory mediators may become an option.

Clonal Hematopoiesis and Acute Ischemic Stroke Outcomes

OBJECTIVE

The effect of clonal hematopoiesis of indeterminate potential (CHIP) on the manifestation and clinical outcomes of acute ischemic stroke (AIS) has not been fully elucidated.

METHODS

Patients with AIS were included from a prospective registry coupled with a DNA repository. Targeted next-generation sequencing on 25 genes that are frequently mutated in hematologic neoplasms was performed. The prevalence of CHIP was compared between patients with AIS and age-matched healthy individuals. A multivariate linear or logistic regression model was used to assess the association among CHIP and stroke severity, hemorrhagic transformation, and functional outcome at 90 days.

RESULTS

In total, 380 patients with AIS (mean age = 67.2 ± 12.7 years; 41.3% women) and 446 age-matched controls (mean age = 67.2 ± 8.7 years; 31.4% women) were analyzed. The prevalence of CHIP was significantly higher in patients with AIS than in the healthy controls (29.0 vs 22.0%, with variant allele frequencies of 1.5%, p = 0.024). PPM1D was found to be most significantly associated with incident AIS (adjusted odds ratio [aOR] = 7.85, 95% confidence interval [CI] = 1.83-33.63, p = 0.006). The presence of CHIP was significantly associated with the initial National Institutes of Health Stroke Scale (NIHSS) score (β = 1.67, p = 0.022). Furthermore, CHIP was independently associated with the occurrence of hemorrhagic transformation (65/110 clonal hematopoiesis positive [CH+] vs 56/270 CH negative [CH-], aOR = 5.63, 95% CI = 3.24-9.77, p < 0.001) and 90-day functional disability (72/110 [CH+] vs 99/270 [CH-], aOR = 2.15, 95% CI = 1.20-3.88, p = 0.011).

INTERPRETATION

CH was significantly associated with incident AIS. Moreover, particularly, sequence variations in PPM1D, TET2, and DNMT3A represent a new prognostic factor for AIS. ANN NEUROL 2023;94:836-847.

Prevalence and significance of clonal hematopoiesis of indeterminate potential in lung transplant recipients

BACKGROUND

Clonal hematopoiesis of indeterminate potential (CHIP), the age-related acquisition of somatic mutations that leads to an expanded blood cell clone, has been associated with development of a pro-inflammatory state. An enhanced or dysregulated inflammatory response may contribute to rejection after lung transplantation, however the prevalence of CHIP in lung recipients and influence of CHIP on allograft outcomes is unknown.

METHODS

We analyzed whole-exome sequencing data in 279 lung recipients to detect CHIP, defined by pre-specified somatic mutations in 74 genes known to promote clonal expansion of hematopoietic stem cells. We compared the burden of acute rejection (AR) over the first post-transplant year in lung recipients with vs. without CHIP using multivariable ordinal regression. Multivariate Cox proportional hazards models were used to assess the association between CHIP and CLAD-free survival. An exploratory analysis evaluated the association between the number of CHIP-associated variants and chronic lung allograft dysfunction (CLAD)-free survival.

RESULTS

We detected 64 CHIP-associated mutations in 45 individuals (15.7%), most commonly in TET2 (10.8%), DNMT3A (9.2%), and U2AF1 (9.2%). Patients with CHIP tended to be older but did not significantly differ from patients without CHIP in terms of race or native lung disease. Patients with CHIP did not have a higher incidence of AR over the first post-transplant year (p = 0.45) or a significantly increased risk of death or CLAD (adjusted HR 1.25, 95% CI 0.88-1.78). We did observe a significant association between the number of CHIP variants and CLAD-free survival, specifically patients with 2 or more CHIP-associated variants had an increased risk for death or CLAD (adjusted HR 3.79, 95% CI 1.98-7.27).

CONCLUSIONS

Lung recipients have a higher prevalence of CHIP and a larger variety of genes with CHIP-associated mutations compared with previous reports for the general population. CHIP did not increase the risk of AR, CLAD, or death in lung recipients.

The Role of Clonal Hematopoiesis of Indeterminant Potential and DNA (Cytosine-5)-Methyltransferase Dysregulation in Pulmonary Arterial Hypertension and Other Cardiovascular Diseases

DNA methylation is an epigenetic mechanism that regulates gene expression without altering gene sequences in health and disease. DNA methyltransferases (DNMTs) are enzymes responsible for DNA methylation, and their dysregulation is both a pathogenic mechanism of disease and a therapeutic target. DNMTs change gene expression by methylating CpG islands within exonic and intergenic DNA regions, which typically reduces gene transcription. Initially, mutations in the DNMT genes and pathologic DNMT protein expression were found to cause hematologic diseases, like myeloproliferative disease and acute myeloid leukemia, but recently they have been shown to promote cardiovascular diseases, including coronary artery disease and pulmonary hypertension. We reviewed the regulation and functions of DNMTs, with an emphasis on somatic mutations in DNMT3A, a common cause of clonal hematopoiesis of indeterminant potential (CHIP) that may also be involved in the development of pulmonary arterial hypertension (PAH). Accumulation of somatic mutations in DNMT3A and other CHIP genes in hematopoietic cells and cardiovascular tissues creates an inflammatory environment that promotes cardiopulmonary diseases, even in the absence of hematologic disease. This review summarized the current understanding of the roles of DNMTs in maintenance and de novo methylation that contribute to the pathogenesis of cardiovascular diseases, including PAH.

Clonal Hematopoiesis in Clinical and Experimental Heart Failure With Preserved Ejection Fraction

BACKGROUND

Clonal hematopoiesis (CH), which results from an array of nonmalignant driver gene mutations, can lead to altered immune cell function and chronic disease, and has been associated with worse outcomes in patients with heart failure (HF) with reduced ejection fraction. However, the role of CH in the prognosis of HF with preserved ejection fraction (HFpEF) has been understudied. This study aimed to characterize CH in patients with HFpEF and elucidate its causal role in a murine model.

METHODS

Using a panel of 20 candidate CH driver genes and a variant allele fraction cutoff of 0.5%, ultradeep error-corrected sequencing identified CH in a cohort of 81 patients with HFpEF (mean age, 71±6 years; ejection fraction, 63±5%) and 36 controls without a diagnosis of HFpEF (mean age, 74±7 years; ejection fraction, 61.5±8%). CH was also evaluated in a replication cohort of 59 individuals with HFpEF.

RESULTS

Compared with controls, there was an enrichment of TET2-mediated CH in the HFpEF patient cohort (12% versus 0%, respectively; P=0.02). In the HFpEF cohort, patients with CH exhibited exacerbated diastolic dysfunction in terms of E/e' (14.9 versus 11.7, respectively; P=0.0096) and E/A (1.69 versus 0.89, respectively; P=0.0206) compared with those without CH. The association of CH with exacerbated diastolic dysfunction was corroborated in a validation cohort of individuals with HFpEF. In accordance, patients with HFpEF, an age ≥70 years, and CH exhibited worse prognosis in terms of 5-year cardiovascular-related hospitalization rate (hazard ratio, 5.06; P=0.042) compared with patients with HFpEF and an age ≥70 years without CH. To investigate the causal role of CH in HFpEF, nonconditioned mice underwent adoptive transfer with Tet2-wild-type or Tet2-deficient bone marrow and were subsequently subjected to a high-fat diet/L-NAME (Nω-nitro-l-arginine methyl ester) combination treatment to induce features of HFpEF. This model of Tet2-CH exacerbated cardiac hypertrophy by heart weight/tibia length and cardiomyocyte size, diastolic dysfunction by E/e' and left ventricular end-diastolic pressure, and cardiac fibrosis compared with the Tet2-wild-type condition.

CONCLUSIONS

CH is associated with worse heart function and prognosis in patients with HFpEF, and a murine experimental model of Tet2-mediated CH displays greater features of HFpEF.

Clonal haematopoiesis - a novel entity that modifies pathological processes in elderly

Progress in the development of new sequencing techniques with wider accessibility and higher sensitivity of the protocol of deciphering genome particularities led to the discovery of a new phenomenon - clonal haematopoiesis. It is characterized by the presence in the bloodstream of elderly people a minor clonal population of cells with mutations in certain genes, but without any sign of disease related to the hematopoietic system. Here we will review this recent advancement in the field of clonal haematopoiesis and how it may affect the disease's development in old age.

A novel web-based calculator to predict 30-day all-cause in-hospital mortality for 7,202 elderly patients with heart failure in ICUs: a multicenter retrospective cohort study in the United States

Background and aims

Heart failure (HF) is a significant cause of in-hospital mortality, especially for the elderly admitted to intensive care units (ICUs). This study aimed to develop a web-based calculator to predict 30-day in-hospital mortality for elderly patients with HF in the ICU and found a relationship between risk factors and the predicted probability of death.

Methods and results

Data (N = 4450) from the MIMIC-III/IV database were used for model training and internal testing. Data (N = 2,752) from the eICU-CRD database were used for external validation. The Brier score and area under the curve (AUC) were employed for the assessment of the proposed nomogram. Restrictive cubic splines (RCSs) found the cutoff values of variables. The smooth curve showed the relationship between the variables and the predicted probability of death. A total of 7,202 elderly patients with HF were included in the study, of which 1,212 died. Multivariate logistic regression analysis showed that 30-day mortality of HF patients in ICU was significantly associated with heart rate (HR), 24-h urine output (24h UOP), serum calcium, blood urea nitrogen (BUN), NT-proBNP, SpO2, systolic blood pressure (SBP), and temperature (P < 0.01). The AUC and Brier score of the nomogram were 0.71 (0.67, 0.75) and 0.12 (0.11, 0.15) in the testing set and 0.73 (0.70, 0.75), 0.13 (0.12, 0.15), 0.65 (0.62, 0.68), and 0.13 (0.12, 0.13) in the external validation set, respectively. The RCS plot showed that the cutoff values of variables were HR of 96 bmp, 24h UOP of 1.2 L, serum calcium of 8.7 mg/dL, BUN of 30 mg/dL, NT-pro-BNP of 5121 pg/mL, SpO2 of 93%, SBP of 137 mmHg, and a temperature of 36.4°C.

Conclusion

Decreased temperature, decreased SpO2, decreased 24h UOP, increased NT-proBNP, increased serum BUN, increased or decreased SBP, fast HR, and increased or decreased serum calcium increase the predicted probability of death. The web-based nomogram developed in this study showed good performance in predicting 30-day in-hospital mortality for elderly HF patients in the ICU.

Incidence and predictors of anthracycline-related left ventricular dysfunction in acute myeloid leukemia

INTRODUCTION

Anthracycline-related left ventricular dysfunction (ARLVD) is a concern in patients with acute myeloid leukemia (AML) undergoing anthracyclinecontaining induction chemotherapy. However, the incidence of ARLVD in the modern era of routine pretreatment left ventricular ejection fraction (LVEF) echocardiographic assessment, as well as the clinical and genetic predictors of ARLVD are not well understood.

METHODS

Consecutive adult patients with AML receiving anthracycline-containing induction chemotherapy at the Dana-Farber Cancer Institute from 2014 to 2022 were studied. Inclusion criteria included availability of a pre and post chemotherapy echocardiogram to assess the LVEF, pre-treatment LVEF > 50 %, as well as comprehensive diagnostic next generation sequencing assessing for the presence of myeloid mutations. The primary endpoint was the incidence of ARLVD defined as LVEF < 50 % post-induction.

RESULTS

Out of 419 patients meeting inclusion criteria, 34 (8%) patients developed ARLVD. Among the 122/419 patients who did not undergo planned allogeneic stem cell transplantation (allo-SCT), ARLVD was the deciding factor for ineligibility in 4 patients (1%). Baseline cardiovascular comorbidities (hypertension, diabetes mellitus, hyperlipidemia, smoking and coronary artery disease) and cumulative anthracycline dose were not predictive of post-induction ARLVD. However, the presence of a JAK2 mutation (but not other myeloid mutations) was associated with an increased risk of ARLVD in multivariable analysis (OR 8.34, 95 % CI 1.55-39.3, p = 0.007).

DISCUSSION

In a group of AML patients with normal LVEF prior to anthracycline-containing induction chemotherapy, ARLVD was infrequent and did not commonly preclude post-remission allo-SCT consolidation. Genetic predictors of ARLVD require further investigation in a larger patient cohort.

Inflammatory Mechanisms in Heart Failure with Preserved Ejection Fraction

Heart failure with preserved ejection fraction (HFpEF) is now the most common form of heart failure and a significant public health concern for which limited effective therapies exist. Inflammation triggered by comorbidity burden is a critical element of HFpEF pathophysiology. Here, we discuss evidence for comorbidity-driven systemic and myocardial inflammation and the mechanistic role of inflammation in pathological myocardial remodeling in HFpEF.

Clonal Hematopoiesis as a Molecular Risk Factor for Doxorubicin-Induced Cardiotoxicity: A Proof-of-Concept Study

PURPOSE

The main dose-limiting toxicity of anthracyclines is cardiotoxicity. Clonal hematopoiesis (CH), somatic mutations in hematopoietic stem or progenitor cells in patients without hematologic malignancy, is also associated with risk for adverse cardiovascular events and worse outcomes overall. We hypothesize that CH increases risk for doxorubicin-induced cardiotoxicity (DIC).

METHODS

We conducted a retrospective cohort study in patients treated with doxorubicin for cancer (N = 100). Patients (n = 25) had incident symptomatic heart failure, decline in left ventricular ejection fraction, or arrhythmia. CH was identified using paired peripheral blood and tumor DNA.

RESULTS

After adjusting for age at doxorubicin initiation, diabetes, dyslipidemia, and chest radiation, high cumulative dose of doxorubicin (>240 mg/m2; odds ratio [OR], 7.00; 95% CI, 1.77 to 27.74; P = .0056), CH (OR, 8.58; 95% CI, 2.05 to 35.99; P = .0033), and history of smoking (OR, 3.15; 95% CI, 1.00 to 9.93; P = .0495) were associated with DIC.

CONCLUSION

This study provides preliminary evidence for CH as a predictive risk factor for DIC, which, with further investigation, could serve as an important precision medicine biomarker for the large number of patients with cancer who have CH.

Cell-intrinsic effects of clonal hematopoiesis in heart failure

Clonal hematopoiesis of indeterminate potential (CHIP) is caused by somatic mutations in hematopoietic stem cells and associates with worse prognosis in patients with heart failure. Patients harboring CHIP mutations show enhanced inflammation. However, whether these signatures are derived from the relatively low number of cells harboring mutations or are indicators of systemic pro-inflammatory activation that is associated with CHIP is unclear. Here we assess the cell-intrinsic effects of CHIP mutant cells in patients with heart failure. Using an improved single-cell sequencing pipeline (MutDetect-Seq), we show that DNMT3A mutant monocytes, CD4+ T cells and NK cells exhibit altered gene expression profiles. While monocytes showed increased genes associated with inflammation and phagocytosis, T cells and NK cells present increased activation signatures and effector functions. Increased paracrine signaling pathways are predicted and validated between mutant and wild-type monocytes and T cells, which amplify inflammatory circuits. Altogether, these data provide novel insights into how CHIP might promote a worse prognosis in patients with heart failure.

Clonal Hematopoiesis Has Prognostic Value in Dilated Cardiomyopathy Independent of Age and Clone Size

BACKGROUND

Clonal hematopoiesis (CH) gives rise to mutated leukocyte clones that induce cardiovascular inflammation and thereby impact the disease course in atherosclerosis and ischemic heart failure. CH of indeterminate potential refers to a variant allele frequency (VAF; a marker for clone size) in blood of ≥2%. The impact of CH clones-including small clone sizes (VAF <0.5%)-in nonischemic dilated cardiomyopathy (DCM) remains largely undetermined.

OBJECTIVES

The authors sought to establish the prognostic impact of CH in DCM including small clones.

METHODS

CH is determined using an ultrasensitive single-molecule molecular inversion probe technique that allows detection of clones down to a VAF of 0.01%. Cardiac death and all-cause mortality were analyzed using receiver-operating characteristic curve-optimized VAF cutoff values.

RESULTS

A total of 520 DCM patients have been included. One hundred and nine patients (21%) had CH driver mutations, of which 45 had a VAF of ≥2% and 31 <0.5%. The median follow-up duration was 6.5 years [IQR: 4.7-9.7 years]. DCM patients with CH have a higher risk of cardiac death (HR: 2.33 using a VAF cutoff of 0.36%, 95% CI: 1.24-4.40) and all-cause mortality (HR: 1.72 using a VAF cutoff of 0.06%, 95% CI: 1.10-2.69), independent of age, sex, left ventricular ejection fraction, and New York Heart Association classification.

CONCLUSIONS

CH predicts cardiac death and all-cause mortality in DCM patients with optimal thresholds for clone size of 0.36% and 0.06%, respectively. Therefore, CH is prognostically relevant, independent of clone size in patients with DCM.

Clonal Hematopoiesis of Indeterminate Potential From a Heart Failure Specialist's Point of View

Clonal hematopoiesis of indeterminate potential (CHIP) is a common bone marrow abnormality induced by age-related DNA mutations, which give rise to proinflammatory immune cells. These immune cells exacerbate atherosclerotic cardiovascular disease and may induce or accelerate heart failure. The mechanisms involved are complex but point toward a central role for proinflammatory macrophages and an inflammasome-dependent immune response (IL-1 [interleukin-1] and IL-6 [interleukin-6]) in the atherosclerotic plaque or directly in the myocardium. Intracardiac inflammation may decrease cardiac function and induce cardiac fibrosis, even in the absence of atherosclerotic cardiovascular disease. The pathophysiology and consequences of CHIP may differ among implicated genes as well as subgroups of patients with heart failure, based on cause (ischemic versus nonischemic) and ejection fraction (reduced ejection fraction versus preserved ejection fraction). Evidence is accumulating that CHIP is associated with cardiovascular mortality in ischemic and nonischemic heart failure with reduced ejection fraction and involved in the development of heart failure with preserved ejection fraction. CHIP and corresponding inflammatory pathways provide a highly potent therapeutic target. Randomized controlled trials in patients with well-phenotyped heart failure, where readily available anti-inflammatory therapies are used to intervene with clonal hematopoiesis, may pave the way for a new area of heart failure treatment. The first clinical trials that target CHIP are already registered.

Cardio-oncology: Shared Genetic, Metabolic, and Pharmacologic Mechanism

PURPOSE OF REVIEW

The article aims to investigate the complex relationship between cancer and cardiovascular disease (CVD), with a focus on the effects of cancer treatment on cardiac health.

RECENT FINDINGS

Advances in cancer treatment have improved long-term survival rates, but CVD has emerged as a leading cause of morbidity and mortality in cancer patients. The interplay between cancer itself, treatment methods, homeostatic changes, and lifestyle modifications contributes to this comorbidity. Recent research in the field of cardio-oncology has revealed common genetic mutations, risk factors, and metabolic features associated with the co-occurrence of cancer and CVD. This article provides a comprehensive review of the latest research in cardio-oncology, including common genetic mutations, risk factors, and metabolic features, and explores the interactions between cancer treatment and CVD drugs, proposing novel approaches for the management of cancer and CVD.

Leukocytes carrying Clonal Hematopoiesis of Indeterminate Potential (CHIP) Mutations invade Human Atherosclerotic Plaques

Background

Leukocyte progenitors derived from clonal hematopoiesis of undetermined potential (CHIP) are associated with increased cardiovascular events. However, the prevalence and functional relevance of CHIP in coronary artery disease (CAD) are unclear, and cells affected by CHIP have not been detected in human atherosclerotic plaques.

Methods

CHIP mutations in blood and tissues were identified by targeted deep-DNA-sequencing (DNAseq: coverage >3,000) and whole-genome-sequencing (WGS: coverage >35). CHIP-mutated leukocytes were visualized in human atherosclerotic plaques by mutaFISH™. Functional relevance of CHIP mutations was studied by RNAseq.

Results

DNAseq of whole blood from 540 deceased CAD patients of the Munich cardIovaScular StudIes biObaNk (MISSION) identified 253 (46.9%) CHIP mutation carriers (mean age 78.3 years). DNAseq on myocardium, atherosclerotic coronary and carotid arteries detected identical CHIP mutations in 18 out of 25 mutation carriers in tissue DNA. MutaFISH™ visualized individual macrophages carrying DNMT3A CHIP mutations in human atherosclerotic plaques. Studying monocyte-derived macrophages from Stockholm-Tartu Atherosclerosis Reverse Networks Engineering Task (STARNET; n=941) by WGS revealed CHIP mutations in 14.2% (mean age 67.1 years). RNAseq of these macrophages revealed that expression patterns in CHIP mutation carriers differed substantially from those of non-carriers. Moreover, patterns were different depending on the underlying mutations, e.g. those carrying TET2 mutations predominantly displayed upregulated inflammatory signaling whereas ASXL1 mutations showed stronger effects on metabolic pathways.

Conclusions

Deep-DNA-sequencing reveals a high prevalence of CHIP mutations in whole blood of CAD patients. CHIP-affected leukocytes invade plaques in human coronary arteries. RNAseq data obtained from macrophages of CHIP-affected patients suggest that pro-atherosclerotic signaling differs depending on the underlying mutations. Further studies are necessary to understand whether specific pathways affected by CHIP mutations may be targeted for personalized treatment.

Blockade of IL-6 signaling alleviates atherosclerosis in Tet2-deficient clonal hematopoiesis

Clonal hematopoiesis (CH) increases the risk of atherosclerotic cardiovascular disease possibly due to increased plaque inflammation. Human studies suggest that limitation of interleukin-6 (IL-6) signaling could be beneficial in people with large CH clones, particularly in TET2 CH. Here we show that IL-6 receptor antibody treatment reverses the atherosclerosis promoted by Tet2 CH, with reduction of monocytosis, lesional macrophage burden and macrophage colony-stimulating factor 1 receptor (CSF1R) expression. IL-6 induces expression of Csf1r in Tet2-deficient macrophages through enhanced STAT3 binding to its promoter. In mouse and human Tet2-deficient macrophages, IL-6 increases CSF1R expression and enhances macrophage survival. Treatment with the CSF1R inhibitor PLX3397 reversed accelerated atherosclerosis in Tet2 CH mice. Our study demonstrates the causality of IL-6 signaling in Tet2 CH accelerated atherosclerosis, identifies IL-6-induced CSF1R expression as a critical mechanism and supports blockade of IL-6 signaling as a potential therapy for CH-driven cardiovascular disease.

Clonal Hematopoiesis of Indeterminate Potential Predicts Adverse Outcomes in Patients With Atherosclerotic Cardiovascular Disease

BACKGROUND

Clonal hematopoiesis of indeterminate potential (CHIP)-the age-related clonal expansion of blood stem cells with leukemia-associated mutations-is a novel cardiovascular risk factor. Whether CHIP remains prognostic in individuals with established atherosclerotic cardiovascular disease (ASCVD) is less clear.

OBJECTIVES

This study tested whether CHIP predicts adverse outcomes in individuals with established ASCVD.

METHODS

Individuals aged 40 to 70 years from the UK Biobank with established ASCVD and available whole-exome sequences were analyzed. The primary outcome was a composite of ASCVD events and all-cause mortality. Associations of any CHIP (variant allele fraction ≥2%), large CHIP clones (variant allele fraction ≥10%), and the most commonly mutated driver genes (DNMT3A, TET2, ASXL1, JAK2, PPM1D/TP53 [DNA damage repair genes], and SF3B1/SRSF2/U2AF1 [spliceosome genes]) with incident outcomes were compared using unadjusted and multivariable-adjusted Cox regression.

RESULTS

Of 13,129 individuals (median age: 63 years) included, 665 (5.1%) had CHIP. Over a median follow-up of 10.8 years, any CHIP and large CHIP at baseline were associated with adjusted HRs of 1.23 (95% CI: 1.10-1.38; P < 0.001) and 1.34 (95% CI: 1.17-1.53; P < 0.001), respectively, for the primary outcome. TET2 and spliceosome CHIP, especially large clones, were most strongly associated with adverse outcomes (large TET2 CHIP: HR: 1.89; 95% CI: 1.40-2.55; P <0.001; large spliceosome CHIP: HR: 3.02; 95% CI: 1.95-4.70; P < 0.001).

CONCLUSIONS

CHIP is independently associated with adverse outcomes in individuals with established ASCVD, with especially high risks observed in TET2 and SF3B1/SRSF2/U2AF1 CHIP.

Risk factors for clonal hematopoiesis of indeterminate potential and mosaic chromosomal alterations

Clonal hematopoiesis of indeterminate potential (CHIP) and mosaic chromosomal alterations (mCAs) of the autosomes, X, and Y chromosomes are aging-related somatic mutations detectable in peripheral blood. The presence of these acquired mutations predisposes otherwise healthy adults to increased risk of several chronic aging-related conditions including hematologic cancers, atherosclerotic cardiovascular diseases, other inflammatory conditions, and mortality. While the public health impact and disease associations of these blood-derived somatic mutations continue to expand, the inherited, behavioral/lifestyle, environmental risk factors and comorbid conditions that influence their occurrence and progression have been less well characterized. Age is the strongest risk factor for all types of CHIP and mCAs. CHIP and mCAs are generally more common in individuals of European than non-European ancestry. Evidence for a genetic predisposition has been strongest for mosaic loss of Y chromosome in men. Genome-wide association studies have recently begun to identify common and rare germline genetic variants associated with CHIP and mCAs. These loci include genes involving cell cycle regulation, cell proliferation/survival, hematopoietic progenitor cell regulation, DNA damage repair, and telomere maintenance. Some loci, such as TERT, ATM, TP53, CHEK2, and TCL1A, have overlapping associations with different types of CHIP, mCAs, and cancer predisposition. Various environmental or co-morbid contexts associated with presence or expansion of specific CHIP or mCA mutations are beginning to be elucidated, such as cigarette smoking, diet, cancer chemotherapy, particulate matter, and premature menopause. Further characterization of the germline genetic and environmental correlates of CHIP/mCAs may inform our ability to modify their progression and ultimately reduce the risk and burden of chronic diseases associated with these clonal somatic phenomena.

Clonal Hematopoiesis of Indeterminate Potential Is Associated With Coronary Microvascular Dysfunction In Early Nonobstructive Coronary Artery Disease

BACKGROUND

Clonal hematopoiesis (CH) of indeterminate potential (CHIP) is a risk factor for cardiovascular disease. The relationship between CHIP and coronary microvascular dysfunction (CMD) is unknown. The current study examines the association between CHIP and CH with CMD and the potential relationships in risk for adverse cardiovascular outcomes.

METHODS

In this retrospective observational study, targeted next-generation sequencing was performed for 177 participants with no coronary artery disease who presented with chest pain and underwent routine coronary functional angiogram. Patients with somatic mutations in leukemia-associated driver genes in hematopoietic stem and progenitor cells were examined; CHIP was considered at a variant allele fraction ≥2%; CH was considered at a variant allele fraction ≥1%. CMD was defined as coronary flow reserve to intracoronary adenosine of ≤2. Major adverse cardiovascular events considered were myocardial infarction, coronary revascularization, or stroke.

RESULTS

A total of 177 participants were examined. Mean follow-up was 12±7 years. A total of 17 patients had CHIP and 28 had CH. Cases with CMD (n=19) were compared with controls with no CMD (n=158). Cases were 56±9 years, were 68% women, and had more CHIP (27%; P=0.028) and CH (42%; P=0.001) than controls. CMD was associated with independent risk for major adverse cardiovascular events (hazard ratio, 3.89 [95% CI, 1.21-12.56]; P=0.023), and 32% of this risk was mediated by CH. The risk mediated by CH was ≈0.5× as large as the direct effect of CMD on major adverse cardiovascular events.

CONCLUSIONS

In humans, we observe patients with CMD are more likely to have CHIP, and nearly one-third of major adverse cardiovascular events in CMD are mediated by CH.

Hematopoietic Somatic Mosaicism Is Associated With an Increased Risk of Postoperative Atrial Fibrillation

BACKGROUND

On-pump cardiac surgery triggers sterile inflammation and postoperative complications such as postoperative atrial fibrillation (POAF). Hematopoietic somatic mosaicism (HSM) is a recently identified risk factor for cardiovascular diseases and results in a shift toward a chronic proinflammatory monocyte transcriptome and phenotype.

OBJECTIVES

The aim of this study was to assess the prevalence, characteristics, and impact of HSM on preoperative blood and myocardial myeloid cells as well as on outcomes after cardiac surgery.

METHODS

Blood DNA from 104 patients referred for surgical aortic valve replacement (AVR) was genotyped using the HemePACT panel (576 genes). Four screening methods were applied to assess HSM, and postoperative outcomes were explored. In-depth blood and myocardial leukocyte phenotyping was performed in selected patients using mass cytometry and preoperative and postoperative RNA sequencing analysis of classical monocytes.

RESULTS

The prevalence of HSM in the patient cohort ranged from 29%, when considering the conventional HSM panel (97 genes) with variant allelic frequencies ≥2%, to 60% when considering the full HemePACT panel and variant allelic frequencies ≥1%. Three of 4 explored HSM definitions were significantly associated with higher risk for POAF. On the basis of the most inclusive definition, HSM carriers exhibited a 3.5-fold higher risk for POAF (age-adjusted OR: 3.5; 95% CI: 1.52-8.03; P = 0.003) and an exaggerated inflammatory response following AVR. HSM carriers presented higher levels of activated CD64+CD14+CD16- circulating monocytes and inflammatory monocyte-derived macrophages in presurgery myocardium.

CONCLUSIONS

HSM is frequent in candidates for AVR, is associated with an enrichment of proinflammatory cardiac monocyte-derived macrophages, and predisposes to a higher incidence of POAF. HSM assessment may be useful in the personalized management of patients in the perioperative period. (Post-Operative Myocardial Incident & Atrial Fibrillation [POMI-AF]; NCT03376165).