Association of Mutations Contributing to Clonal Hematopoiesis With Prognosis in Chronic Ischemic Heart Failure

Clonal hematopoiesis, cardiovascular disease and cancer treatment-induced cardiotoxicity

Clonal hematopoiesis (CH) arises when a substantial proportion of mature blood cells is derived from a single hematopoietic stem cell lineage. It is considered to be a premalignant state that predisposes individuals to an increased risk of cancers. Recently, emerging evidence has demonstrated a strong association between CH and both the incidence and mortality of cardiovascular diseases (CVD), with the relative risks being comparable to those attributed to traditional cardiovascular risk factors. In addition, CH has been suggested to play a role in CVD and anti-cancer treatment-related cardiotoxicity amongst cancer survivors. Moreover, certain forms of chemotherapy and radiation therapy have been shown to promote the clonal expansion of specific CH-related mutations. Consequently, CH may play a substantial role in the realm of cardio-oncology. In this review, we discuss the association between CH with cancer and CVD, with a special focus on anti-cancer treatment-related cardiotoxicity, discuss possible future research avenues and propose a systematic approach for clinical practice.

Clonal haematopoiesis of indeterminate potential: an emerging risk factor for type 2 diabetes and related complications

The accumulation of acquired somatic mutations is a natural consequence of ageing, but the pathophysiological implications of these mutations beyond cancer are only beginning to be understood. Most somatic mutations are functionally neutral, but a few may confer a competitive advantage to a stem cell, driving its clonal expansion. When such a mutation arises in haematopoietic stem cells, it leads to clonal haematopoiesis, in which a significant proportion of blood cells originate from the mutant stem cell and share the same mutation. Clonal haematopoiesis of indeterminate potential (CHIP), a specific subset of clonal haematopoiesis driven by myeloid leukaemia-related somatic mutations, has been linked to a higher risk of various age-related conditions, particularly CVD, by exacerbating inflammatory responses. Emerging evidence suggests that CHIP may also contribute to the pathogenesis of type 2 diabetes and some of its complications. This review synthesises current knowledge on CHIP and its potential as a novel risk factor for type 2 diabetes, highlighting the need for further research to clarify this relationship and to explore its potential value in developing personalised preventive care strategies for type 2 diabetes and related conditions.

Clonal haematopoiesis in cardiovascular disease: prognostic role and novel therapeutic target

Clonal haematopoiesis is the clonal expansion of blood stem cells with acquired mutations. Clonal haematopoiesis of indeterminate potential (CHIP), traditionally defined as clonal haematopoiesis driven by a pre-leukaemic mutation in at least 2% of sequenced alleles, affects 10-20% of individuals aged >70 years. Although CHIP is considered a precursor condition for haematological malignancies, population-based data suggest that the majority of CHIP-associated mortality is attributable to non-malignant conditions, such as cardiovascular disease. Observational human studies have shown that CHIP is a strong and independent predictor of the onset and progression of atherosclerotic cardiovascular disease, heart failure and arrhythmia. In addition, findings from animal experiments suggest that CHIP is causally involved in these diseases and might be a risk factor that can be targeted with therapeutics. As our understanding of the cardiovascular implications of CHIP and other types of clonal haematopoiesis rapidly expands, it has become increasingly clear that clonal haematopoiesis subtypes have substantial heterogeneity with respect to magnitude of effect and underlying mechanisms for different cardiovascular diseases. In this Review, we discuss clonal haematopoiesis as a prognostic factor for numerous cardiovascular diseases, highlight its potential as a therapeutic target and propose a potential role for CHIP in cardiovascular precision medicine.

Clonal hematopoiesis of indeterminate potential: contribution to disease and promising interventions

In clonal hematopoiesis of indeterminate potential (CHIP), subpopulations of blood cells carrying somatic mutations expand as the individual ages, and this expansion may elevate risk of blood cancers as well as cardiovascular disease. Individuals at higher risk of CHIP and therefore of CHIP-associated disease can be identified through mutational profiling, and the apparently central role of inflammation in CHIP-associated disease has emerged as a potential therapeutic target. While CHIP is often associated with negative health outcomes, emerging evidence suggests that some CHIP-related mutations may also exert beneficial effects, indicating a more complex role in human health. This review examines current understanding of the epidemiology and clinical significance of CHIP and the role of inflammation in driving its association with disease risk. It explores the mechanisms linking CHIP to inflammation and risk of cardiovascular and other diseases, as well as the potential of personalizing therapies against those diseases for individuals with CHIP.

Clonal Hematopoiesis of Indeterminate Potential and Atrial Fibrillation: Insights into Pathophysiology and Clinical Implications

Clonal hematopoiesis of indeterminate potential (CHIP) has emerged as a novel risk factor for cardiovascular diseases. CHIP is characterized by the expansion of hematopoietic stem cell clones harboring somatic mutations in genes such as TET2, DNMT3A, and ASXL1, which are implicated in inflammation, atrial remodeling, and hypercoagulability. These mutations foster a pro-inflammatory and pro-thrombotic environment conducive to arrhythmogenesis, thereby linking CHIP to the development and progression of atrial fibrillation (AF). Mechanistic insights indicate that CHIP contributes to atrial fibrosis, disrupts calcium signaling, and exacerbates oxidative stress, all of which heighten susceptibility to AF. Clinical studies, including epidemiological and Mendelian randomization analyses, further support the association between CHIP and an increased risk of both incident and progressive AF, with specific mutations such as TET2 and ASXL1 identified as significant contributors. Additionally, CHIP has been linked to adverse outcomes in AF, including elevated rates of heart failure, thromboembolism, and mortality. Understanding CHIP's role in AF pathophysiology offers opportunities for the development of precision medicine approaches, providing novel avenues for early intervention and targeted AF treatment. This review synthesizes current mechanistic and clinical evidence on the role of CHIP in AF, emphasizes its potential as a biomarker for risk stratification, and explores emerging therapeutic strategies targeting CHIP-associated pathways.

TET2 deficiency increases the competitive advantage of hematopoietic stem and progenitor cells through upregulation of thrombopoietin receptor signaling

Ten-Eleven Translocation-2 (TET2) mutations drive the expansion of mutant hematopoietic stem cells (HSCs) in clonal hematopoiesis (CH). However, the precise mechanisms by which TET2 mutations confer a competitive advantage to HSCs remain unclear. Here, through an epigenetic drug screen, we discover that inhibition of disruptor of telomeric silencing 1-like (DOT1L), a H3K79 methyltransferase, selectively reduces the fitness of Tet2 knockout (Tet2KO) hematopoietic stem and progenitor cells (HSPCs). Mechanistically, we find that TET2 deficiency increases H3K79 dimethylation and expression of Mpl, which encodes the thrombopoietin receptor (TPO-R). Correspondingly, TET2 deficiency is associated with a higher proportion of primitive Mpl-expressing (Mpl+) cells in the HSC compartment. Importantly, inhibition of Mpl expression or the signaling downstream of TPO-R is sufficient to reduce the competitive advantage of murine and human TET2-deficient HSPCs. Our findings demonstrate a critical role for aberrant TPO-R signaling in TET2 mutation-driven CH and uncover potential therapeutic strategies against this condition.

Plaque erosion risk and JAK2 V617F variant

BACKGROUND AND AIMS

Clonal haematopoiesis of indeterminate potential (CHIP) can increase the risk of myocardial infarction (MI). Among various CHIP mutations, JAK2 V617F substantially elevated this risk. However, the specific associations between JAK2 V617F and two mechanisms of MI, plaque erosion and plaque rupture, remain unclear.

METHODS

Case-control studies investigated these associations. A total of 728 erosion cases, 919 rupture cases, and 804 controls were included from our centre. Digital-drop polymerase chain reaction was performed on these individuals to identify the presence of JAK2 V617F. Previous experimental work has implicated neutrophils in the pathogenesis of erosion in the presence of this mutation. Thus, single-cell RNA sequencing of neutrophils from both JAK2 V617F carriers and healthy donors was performed to seek the potential mechanisms responsible for erosion associated with JAK2 V617F.

RESULTS

Among the participants, 26 (3.57%) erosion patients, 7 (.76%) rupture patients, and 3 (.37%) controls were identified as JAK2 V617F carriers with a variant allele frequency (VAF) ≥1%. The carriers among the erosion patients exhibited higher platelet counts and lower glycated haemoglobin and blood lipid levels. Logistic regression analysis, considering erosion or rupture as separate cases, revealed that JAK2 V617F carriers with a VAF ≥1% showed a significant association with erosion [odds ratio (OR) 16.246, 95% confidence interval (CI) 4.624-57.080, P < .0001], but not with rupture (OR 1.677, 95% CI .379-7.415, P = .495). Single-cell RNA-sequencing data indicated that neutrophils from JAK2 V617F carriers displayed augmented expression levels of genes and gene sets associated with activation, adhesion, migration, and granule secretion.

CONCLUSIONS

JAK2 V617F linked to a high risk of erosion, an association to which enhanced neutrophil activation may contribute.

Shared molecular, cellular, and environmental hallmarks in cardiovascular disease and cancer: Any place for drug repurposing?

Cancer and cardiovascular disease (CVD) are the 2 biggest killers worldwide. Specific treatments have been developed for the 2 diseases. However, mutual therapeutic targets should be considered because of the overlap of cellular and molecular mechanisms. Cancer research has grown at a fast pace, leading to an increasing number of new mechanistic treatments. Some of these drugs could prove useful for treating CVD, which realizes the concept of cancer drug repurposing. This review provides a comprehensive outline of the shared hallmarks of cancer and CVD, primarily ischemic heart disease and heart failure. We focus on chronic inflammation, altered immune response, stromal and vascular cell activation, and underlying signaling pathways causing pathological tissue remodeling. There is an obvious scope for targeting those shared mechanisms, thereby achieving reciprocal preventive and therapeutic benefits. Major attention is devoted to illustrating the logic, advantages, challenges, and viable examples of drug repurposing and discussing the potential influence of sex, gender, age, and ethnicity in realizing this approach. Artificial intelligence will help to refine the personalized application of drug repurposing for patients with CVD. SIGNIFICANCE STATEMENT: Cancer and cardiovascular disease (CVD), the 2 biggest killers worldwide, share several underlying cellular and molecular mechanisms. So far, specific therapies have been developed to tackle the 2 diseases. However, the development of new cardiovascular drugs has been slow compared with cancer drugs. Understanding the intersection between pathological mechanisms of the 2 diseases provides the basis for repurposing cancer therapeutics for CVD treatment. This approach could allow the rapid development of new drugs for patients with CVDs.

Long-term rate of heart failure in patients with autoimmune disease: A nationwide cohort study

AIMS

Although certain autoimmune diseases (AIDs) have been associated with an increased rate of heart failure (HF), data on the long-term rate of HF across the spectrum of AIDs are lacking. We investigated the long-term rate of HF in individuals with a history of 28 different AIDs.

METHODS AND RESULTS

Individuals diagnosed with an AID (2000-2021) were identified through Danish nationwide registries. Each patient with AID was matched with four individuals from the background population by age, sex, and year of inclusion. Multivariable Cox regression was used to compare the rate of HF between the AID and the background population, overall and according to individual AIDs. In total, 272 959 patients diagnosed with AID were matched with 1 091 836 individuals without AID (median age 55 years; 62% women; median follow-up 7.9 years). The 10-year cumulative incidence of HF was 5.2% for patients with AID and 3.5% for matched individuals. Patients with any AID had a higher associated rate of HF than matched individuals (hazard ratio [HR] 1.55, 95% confidence interval [CI] 1.52-1.59). Patients with each of the AIDs had a higher associated rate of incident HF compared with matched individuals from the background population, although the association was not statistically significant for Reiter's and Behcet's disease. The highest relative rates were observed in patients with systemic sclerosis (HR 3.31, 95% CI 2.63-4.16) and Addison's disease (HR 3.03, 95% CI 2.35-3.91).

CONCLUSION

Patients with AID, irrespective of the type, had a higher associated rate of HF compared to the background population. Further research is needed to clarify whether screening for cardiovascular risk is beneficial.

Biomarkers in clonal haematopoiesis of indeterminate potential (CHIP) linking cardiovascular diseases, myeloid neoplasms and inflammation

There is increasing evidence that points to ubiquity of clonal haematopoiesis of indeterminate potential (CHIP) especially with rising age. CHIP has been associated with a multitude of inflammatory, cardiovascular and malignant conditions. In this review article, we evaluate the current literature on CHIP and clinical associations with cardiovascular and haematological diseases. We also discuss high risk features of CHIP that predispose to haematological malignancies, as well as further zoom in on the association between clonal haematopoiesis and therapy-related myeloid neoplasm (tMN). CHIP increases risk of atherosclerotic cardiovascular disease and other cardiovascular conditions such as heart failure, arrhythmias and valvular disease. Hematopoietic clones with mutations in TP53 and spliceosome gene U2AF1 in particularly have repeatedly been shown to increase risk for AML. Other factors such as increased clonal size i.e. variant allele fraction (VAF), clonal complexity have also been shown to increase risk for haematological malignancy. In this comprehensive review, we consolidate the most recent advancements in the understanding of clonal haematopoiesis of indeterminate potential (CHIP) and its associations with cardiovascular and haematological disease. This review is also one of the first to focus on potential biochemical markers routinely utilized in clinical practice that may suggest a more sinister progression of CHIP. We hope to provide physicians with a nuanced perspective on the evolving landscape of CHIP, and offering valuable insights into its clinical implications and potential prognostic indicators.

Reconsidering the usual suspects in age-related hematologic disorders: is stem cell dysfunction a root cause of aging?

Aging exerts a profound impact on the hematopoietic system, leading to increased susceptibility to infections, autoimmune diseases, chronic inflammation, anemia, thrombotic events, and hematologic malignancies. Within the field of experimental hematology, the functional decline of hematopoietic stem cells (HSCs) is often regarded as a primary driver of age-related hematologic conditions. However, aging is clearly a complex multifaceted process involving not only HSCs but also mature blood cells and their interactions with other tissues. This review reappraises an HSC-centric view of hematopoietic aging by exploring how the entire hematopoietic hierarchy, from stem cells to mature cells, contributes to age-related disorders. It highlights the decline of both innate and adaptive immunity, leading to increased susceptibility to infections and cancer, and the rise of autoimmunity as peripheral immune cells undergo aging-induced changes. It explores the concept of "inflammaging," where persistent, low-grade inflammation driven by old immune cells creates a cycle of tissue damage and disease. Additionally, this review delves into the roles of inflammation and homeostatic regulation in age-related conditions such as thrombotic events and anemia, arguing that these issues arise from broader dysfunctions rather than stemming from HSC functional attrition alone. In summary, this review highlights the importance of taking a holistic approach to studying hematopoietic aging and its related pathologies. By looking beyond just stem cells and considering the full spectrum of age-associated changes, one can better capture the complexity of aging and attempt to develop preventative or rejuvenation strategies that target multiple facets of this process.

Clonal Hematopoiesis in Women With Breast Cancer

PURPOSE

Clonal hematopoiesis (CH) has been associated with a variety of adverse outcomes, most notably hematologic malignancy and ischemic cardiovascular disease. A series of recent studies also suggest that CH may play a role in the outcomes of patients with solid tumors, including breast cancer. Here, we review the clinical and biological data that underlie potential connections between CH, inflammation, and breast cancer, with a focus on the prevalence and impact of clonal hematopoiesis of indeterminate potential in patients with breast cancer.

METHODS

We summarize data from multiple studies, including a series of cohorts of patients with breast cancer, to assess the prevalence of CH, the relationship between CH and exposure to cytotoxic therapy, and the correlation between CH and breast cancer-specific outcomes.

RESULTS

Our findings indicate that CH is prevalent among patients with breast cancer, particularly those treated with cytotoxic therapies. However, there are no definitive data to support an association between the presence of CH and breast cancer-specific outcomes.

CONCLUSION

Current data do not support routine CH testing in patients with breast cancer, nor should the presence of CH influence decisions regarding breast cancer therapy in most patients. However, larger, long-term studies are necessary to further define the implications of CH in patients with breast cancer and guide clinical decision making.

Revolutionising Cardio-Oncology Care with Precision Genomics

Cardiovascular disease is the worldwide leading cause of mortality among survivors of cancer due in part to the cardiotoxicity of anticancer therapies. This paper explores the progress in precision cardio-oncology, particularly in genetic testing and therapeutics, and its impact on cardiovascular diseases in clinical and laboratory settings. These advancements enable clinicians to better assess risk, diagnose conditions, and deliver personalised, cost-effective therapeutics. Through case studies of cancer-therapy-related cardiac dysfunction, clonal haematopoiesis of indeterminate potential, and polygenic risk scoring, we demonstrate the benefits of incorporating precision genomics in individualised care in cardio-oncology. Furthermore, leveraging real-world genomic data in clinical settings can advance our understanding of long noncoding RNAs and microRNAs, which play important regulatory roles in cardio-oncology. Additionally, employing human-induced pluripotent stem cells to stratify risk and guide prevention strategies represents a promising avenue for modelling precision cardio-oncology. While these advancements showcase the significant progress in genetic approaches, they also raise substantial ethical, legal, and societal concerns. Regulatory oversight of genetic and genomic technologies should therefore evolve suitably to keep up with rapid advancements in technology and analysis. Provider education is crucial for the appropriate use of new genetic and genomic applications, including on the existing protection available for patients regarding genetic information. This can provide confidence for diverse study groups to advance genetic studies looking to develop a comprehensive understanding and effective clinical applications for heterogeneous populations. In clinical settings, the implementation of genetic and genomic applications within electronic medical records can offer point-of-care clinical decision support, thus providing timely information to guide clinical management decisions.

Error-corrected ultradeep next-generation sequencing for detection of clonal haematopoiesis and haematological neoplasms - sensitivity, specificity and accuracy

Clonal haematopoiesis of indeterminate potential (CHIP) is an aging-associated phenomenon that has recently been correlated with a broad spectrum of human diseases, including haematological malignancy, cytopenia, coronary heart disease, stroke, and overall mortality. CHIP is defined as a somatic variant in blood cells with an allele frequency (VAF) ≥ 0.02, however recent reports show smaller clones are associated with poorer clinical outcome. Error-corrected ultradeep next-generation sequencing (NGS) assays detecting variants < 0.02 VAF also have clinical value for monitoring measurable residual disease (MRD) for myeloid neoplasms. However, limited data are available on optimal parameters, limits of detection, and accuracy of ultra-sensitive detection. We investigated parameters to improve accuracy of Illumina sequencing-by-synthesis method, including read depth, input DNA quantity, and molecular barcoding-based data filtering, while adhering to clinical accreditation criteria. Validation data were generated from reference standards and reference samples from a clinically accredited pathology laboratory. Analytical range measurements included linearity and bias, and precision included repeatability, reproducibility and detection rate. The lower limit of detection was ≥ 0.004 (0.4%) at depth > 3,000 × . Trueness measured using reference standards demonstrated a sensitivity, specificity, positive and negative predictive values, and accuracy of 100%, including FLT3-ITD, and 100% concordance was achieved with reference samples for reported variants and absence of variants. Sequencing blood samples from 383 community-dwelling adults (mean depth 3758×) revealed 2,190 somatic variants/sample, > 99.9% were < 0.02 VAF. Our data including cost-benefit analysis enables pathology and research laboratories to make informed decisions for detection of CHIP (VAF ≥ 0.02), sub-CHIP (VAF 0.01-0.02) and MRD (VAF ≥ 0.004).

Clonal hematopoiesis of indeterminate potential, health indicators, and risk of cardiovascular diseases among patients with diabetes: a prospective cohort study

BACKGROUND

Clonal hematopoiesis of indeterminate potential (CHIP) was associated with diabetes and cardiovascular diseases (CVD). However, the effect of CHIP on CVD have not been evaluated among patients with diabetes, and whether maintaining the healthy indictors could mitigate the adverse influence was also unclear.

METHODS

A total of 22,239 adults from the UK Biobank with diabetes and available whole-exome sequence data, and free of CVD were included. Multivariable-adjusted Cox regressions were used to explore the associations of any CHIP (variant allele fraction ≥ 2%), large CHIP (variant allele fraction ≥ 10%), and the top 10 commonly mutated driver genes for CHIP and with risk of CVD. The joint associations between health indicators (body mass index [BMI], HbA1c, blood pressure [BP], and low-density lipoprotein cholesterol [LDL]) and CHIP were further investigated.

RESULTS

Over a median follow-up of 13.2 years, 5366 participants with diabetes developed CVD events. The hazard ratios (HRs) (95% confidence intervals [CIs]) of any CHIP and large CHIP were (1.21, 1.08-1.36) and (1.25, 1.09-1.43) for incident CVD, respectively. Significant associations between any CHIP and coronary heart disease (HR, 95%CI: 1.18, 1.03-1.36) and heart failure (1.73, 1.46-2.06) were observed, but not for stroke (1.14, 0.89-1.48). Gene-specific analyses suggested that the greatest association were for SF3B1 (HR, 95%CI: 2.50, 1.25-5.01) and TET2 (HR, 95%CI: 1.36, 1.07-1.77) with risk of CVD. There was no significant interaction between the four health indicators and CHIP in relation to incident CVD. Compared to patients without CHIP, those with any CHIP and ideal health indicators still exhibited significantly or nonsignificantly higher HRs (BMI: 1.18, 0.82-1.68; HbA1c: 1.12, 0.96-1.30; BP: 1.24, 1.03-1.49; LDL: 1.29, 1.09-1.53). Similar results were demonstrated using large CHIP.

CONCLUSIONS

CHIP is independently associated with an increased risk of CVD in patients with diabetes, regardless of health indicator levels. Diabetic patients with CHIP but ideal health indicators still exhibited higher CVD risk compared with diabetic patients without CHIP.

Clonal Hematopoiesis of Indeterminate Potential and Cardiovascular Health

Clonal hematopoiesis of indeterminate potential (CHIP) is an age-related phenomenon in which somatic mutations lead to clonal expansion of hematopoietic stem cells without the development of hematologic abnormalities. A growing body of literature demonstrates an association between CHIP and cardiovascular disease. This pathophysiology demonstrates a novel connection between global inflammation and cardiovascular morbidity. While there is limited consensus addressing the cardiovascular care of these patients, risk factor optimization and disease surveillance are advisable. Investigation into possible therapies is ongoing and provides promise for the treatment of inflammation contributing to cardiovascular disease in patients with and without CHIP.

Cardio-Oncology and Heart Failure: a Scientific Statement From the Heart Failure Society of America

Heart failure and cancer remain 2 of the leading causes of morbidity and mortality, and the 2 disease entities are linked in a complex manner. Patients with cancer are at increased risk of cardiovascular complications related to the cancer therapies. The presence of cardiomyopathy or heart failure in a patient with new cancer diagnosis portends a high risk for adverse oncology and cardiovascular outcomes. With the rapid growth of cancer therapies, many of which interfere with cardiovascular homeostasis, heart failure practitioners need to be familiar with prevention, risk stratification, diagnosis, and management strategies in cardio-oncology. This Heart Failure Society of America statement addresses the complexities of heart failure care among patients with active cancer diagnoses and cancer survivors. Risk stratification, monitoring and management of cardiotoxicity are presented across stages A through D heart failure, with focused discussion on heart failure with preserved ejection fraction and special populations, such as survivors of childhood and young-adulthood cancers. We provide an overview of the shared risk factors between cancer and heart failure, highlighting heart failure as a form of cardiotoxicity associated with many different cancer therapeutics. Finally, we discuss disparities in the care of patients with cancer and cardiac disease and present a framework for a multidisciplinary-team approach and critical collaboration among heart failure, oncology, palliative care, pharmacy, and nursing teams in the management of these complex patients.

Clonal Hematopoiesis Is Associated With Adverse Clinical Outcomes and Left Ventricular Remodeling in Aortic Stenosis

Background

Clonal hematopoiesis of indeterminate potential (CHIP) has been linked to intensified systemic inflammation and represents a novel risk factor for atherosclerotic cardiovascular diseases, including aortic stenosis (AS).

Objectives

This study aimed to assess the clinical impact of CHIP in a cohort of severe AS patients undergoing transcatheter aortic valve implantation (TAVI).

Methods

We enrolled 110 severe AS patients in this retrospective study. Targeted next-generation sequencing was employed to detect somatic mutations with a variant allele frequency >2% in 16 genes most frequently associated with CHIP. Correlative analyses on clinical, laboratory, and echocardiographic parameters were also performed. The primary endpoint was post-TAVI heart failure hospitalization. Multivariate Cox regression model was used to account for confounding effects of relevant clinical factors.

Results

CHIP was detected in 40 (36.4%) patients in our cohort. The most commonly mutated genes were DNMT3A, TET2, and ASXL1. With a median follow-up of 55.2 months, patients carrying CHIP had a significantly higher heart failure hospitalization rate (adjusted HR: 3.060; 95% CI: 1.090-8.589; P = 0.034) than those without CHIP. Additionally, patients harboring CHIP had higher serum ferritin levels, as well as echocardiographic evidence of left ventricular hypertrophy and diastolic dysfunction.

Conclusions

Our study supports the adverse clinical impact of CHIP in AS patients undergoing TAVI, which could be attributed to systemic inflammation and maladaptive LV remodeling. Prospective trials are anticipated to validate our findings and provide further evidence that CHIP holds the potential of being an actionable therapeutic target in AS.

Clonal hematopoiesis of indeterminate potential and type 2 diabetes mellitus among patients with STEMI: from a prospective cohort study combing bidirectional Mendelian randomization

AIM

Both clonal hematopoiesis of indeterminate potential (CHIP) and type 2 diabetes mellitus (T2DM) are conditions closely associated with advancing age. This study delves into the possible implications and prognostic significance of CHIP and T2DM in patients diagnosed with ST-segment elevation myocardial infarction (STEMI).

METHODS

Deep-targeted sequencing employing a unique molecular identifier (UMI) for the analysis of 42 CHIP mutations-achieving an impressive mean depth of coverage at 1000 × -was conducted on a cohort of 1430 patients diagnosed with acute myocardial infarction (473 patients with T2DM and 930 non-DM subjects). Variant allele fraction ≥ 2.0% indicated the presence of CHIP mutations. The association between CHIP and T2DM was evaluated by the comparison of (i) the prevalence of CHIP mutations among individuals with diabetes versus those without, (ii) the clinical characteristics delineated by CHIP mutations within the cohort of diabetic patients and (iii) the prognostic significance and correlation of CHIP mutations with mortality rates in T2DM subjects. Furthermore, a two-sample bidirectional Mendelian randomization study was performed using genetic instruments from the genome-wide association study for TET2 mutation CH from the UK Biobank (UKB) (2041 cases,173,918 controls) to investigate the causal relationship with T2DM from the FinnGen consortium (65,085 cases and 335,112 controls), and vice versa.

RESULTS

(i) Most commonly CHIP mutations exhibiting a variant allele fraction of ≥ 2.0% were identified in 50/473 (10.6%) patients with T2DM, demonstrating a greater prevalence compared to non-DM subjects [69/930 (7.4%); P < 0.05] across various age groups. (ii) After multivariable adjustment, the mortality of any CHIP mutations were 2.03-fold higher in DM [adjusted hazard ratio (HR) 2.03; 95% confidence interval (CI) 1.07-3.84, P < 0.05]. (iii) In gene-specific analyses, TET2 somatic mutation presented the highest association with mortality among T2DM (adjusted HR 5.24; 95% CI 2.02-13.61, P = 0.001). ASXL1 CHIP mutation which displayed a striking correlation with cardiac death (HR: 3.14; 95% CI 1.24-7.93; P < 0.05) with consistent associations observed among T2DM subgroup (HR: 4.51; 95% CI 1.30-15.6; P < 0.05). (iv) The correlation between PCSK9 and the Tet2-CHIP mutation was observed in both the T2DM cohort (correlation = 0.1215, P = 0.011) and the overall enrolled cohort (correlation = 0.0578, P = 0.0382). (v) Bidirectional Mendelian randomization studies indicated that the development of T2DM increases the propensity for CHIP. However, CHIP does not subsequently accelerate the onset of T2DM.

CONCLUSION

CHIP mutations, particularly TET2, are more prevalent in patients with T2DM compared to individuals without diabetes. The presence of these mutations is associated with adverse clinical outcomes, notably increased mortality rates. Moreover, bidirectional Mendelian randomization analyses provide supporting evidence for a potential causal relationship between TET2-related CHIP and the development of T2DM.

Tet2-mediated clonal hematopoiesis modestly improves neurological deficits and is associated with inflammation resolution in the subacute phase of experimental stroke

Introduction

Recent work has revealed that clonal hematopoiesis (CH) is associated with a higher risk of numerous age-related diseases, including ischemic stroke, however little is known about whether it influences stroke outcome independent of its widespread effects on cardiovascular disease. Studies suggest that leukocytes carrying CH driver mutations have an enhanced inflammatory profile, which could conceivably exacerbate brain injury after a stroke.

Methods

Using a competitive bone marrow transplant model of Tet2-mediated CH, we tested the hypothesis that CH would lead to a poorer outcome after ischemic stroke by augmenting brain inflammation. Stroke was induced in mice by middle cerebral artery occlusion and neurological outcome was assessed at acute (24 h) and subacute (14 d) timepoints. Brains were collected at both time points for histological, immunofluorescence and gene expression assays.

Results

Unexpectedly, Tet2-mediated CH had no effect on acute stroke outcome but led to a reduction in neurological deficits during the subacute phase. This improved neurological outcome was associated with lower levels of brain inflammation as evidenced by lower transcript levels of various inflammatory molecules alongside reduced astrogliosis.

Discussion

These findings suggest that Tet2-mediated CH may have beneficial effects on outcome after stroke, contrasting with the conventional understanding of CH whereby leukocytes with driver mutations promote disease by exacerbating inflammation.

Age-related clonal hematopoiesis and HIV infection are associated with geriatric outcomes: The ARCHIVE study

While HIV infection and clonal hematopoiesis (CH) have been linked with inflammatory dysregulation and an increased risk of aging-related comorbidities, their relationship with clinical geriatric syndromes has not been well defined. In the Age-related Clonal Haematopoiesis in an HIV Evaluation Cohort (ARCHIVE) study (NCT04641013), we measure associations between HIV and CH and geriatric syndromes. Of 345 participants (176 with HIV and 169 without HIV), 23% had at least one mutation associated with CH: 27% with HIV and 18% without HIV (p = 0.048). In adjusted analyses, HIV infection is independently associated with increased phenotypic age acceleration (coefficient 1.73, 95% confidence interval [CI] 0.3, 3.16) and CH is independently associated with being frail (vs. pre-frail/robust; odds ratio 2.38, 95% CI 1.01, 5.67) and with having reduced quality of life (coefficient -2.18, 95% CI -3.92, -0.44). Our findings suggest that HIV is associated with increased biological age and that CH may be used as a biomarker for adverse geriatric outcomes.

Stem cell graft dose and composition could impact on the expansion of donor-derived clones after allogeneic hematopoietic stem cell transplantation - a virtual clinical trial

Introduction

Hematopoietic stem cell transplantation is a potentially curative intervention for a broad range of diseases. However, there is evidence that malignant or pre-malignant clones contained in the transplant can expand in the recipient and trigger donor-derived malignancies. This observation has gained much attention in the context of clonal hematopoiesis, a medical condition where significant amounts of healthy blood cells are derived from a small number of hematopoietic stem cell clones. In many cases the dominating clones carry mutations conferring a growth advantage and thus could undergo malignant transformation in the recipient. Since clonal hematopoiesis exists in a significant proportion of potential stem cell donors, a more detailed understanding of its role for stem cell transplantation is required.

Methods

We propose mechanistic computational models and perform virtual clinical trials to investigate clonal dynamics during and after allogenic hematopoietic stem cell transplantation. Different mechanisms of clonal expansion are considered, including mutation-related changes of stem cell proliferation and self-renewal, aberrant response of mutated cells to systemic signals, and self-sustaining chronic inflammation triggered by the mutated cells.

Results

Model simulations suggest that an aberrant response of mutated cells to systemic signals is sufficient to explain the frequently observed quick expansion of the mutated clone shortly after transplantation which is followed by a stabilization of the mutated cell number at a constant value. In contrary, a mutation-related increase of self-renewal or self-sustaining chronic inflammation lead to ongoing clonal expansion. Our virtual clinical trials suggest that a low number of transplanted stem cells per kg of body weight increases the transplantation-related expansion of donor-derived clones, whereas the transplanted progenitor dose or growth factor support after transplantation have no impact on clonal dynamics. Furthermore, in our simulations the change of the donors' variant allele frequencies in the year before stem cell donation is associated with the expansion of donor-derived clones in the recipient.

Discussion

This in silico study provides insights in the mechanisms leading to clonal expansion and identifies questions that could be addressed in future clinical trials.

Implications of Clonal Hematopoiesis in Hematological and Non-Hematological Disorders

Clonal hematopoiesis (CH) is associated with an increased risk of developing myeloid neoplasms (MNs) such as myelodysplastic neoplasm (MDS) and acute myeloid leukemia (AML). In general, CH comprises clonal hematopoiesis of indeterminate potential (CHIP) and clonal cytopenia of undetermined significance (CCUS). It is an age-related phenomenon characterized by the presence of somatic mutations in hematopoietic stem cells (HSCs) and hematopoietic stem and progenitor cells (HSPCs) that acquire a fitness advantage under selection pressure. Individuals with CHIP have an absolute risk of 0.5-1.0% per year for progressing to MDS or AML. Inflammation, smoking, cytotoxic therapy, and radiation can promote the process of clonal expansion and leukemic transformation. Of note, exposure to chemotherapy or radiation for patients with solid tumors or lymphomas can increase the risk of therapy-related MN. Beyond hematological malignancies, CH also serves as an independent risk factor for heart disease, stroke, chronic obstructive pulmonary disease, and chronic kidney disease. Prognostic models such as the CH risk score and MN-prediction models can provide a framework for risk stratification and clinical management of CHIP/CCUS and identify high-risk individuals who may benefit from close surveillance. For CH or related disorders, therapeutic strategies targeting specific CH-associated mutations and specific selection pressure may have a potential role in the future.

Clonal hematopoiesis impacts frailty in newly diagnosed multiple myeloma patients: a retrospective multicenter analysis

Somatic mutations of hematopoietic cells in the peripheral blood of normal individuals refer to clonal hematopoiesis of indeterminate potential (CHIP), which is associated with a 0.5-1% risk of progression to hematological malignancies and cardiovascular diseases. CHIP has also been reported in Multiple Myeloma (MM) patients, but its biological relevance remains to be elucidated. In this study, high-depth targeted sequencing of peripheral blood from 76 NDMM patients revealed CHIP in 46% of them, with a variant allele frequency (VAF) ranging from ~ 1 to 34%. The most frequently mutated gene was DNMT3A, followed by TET2. More aggressive disease features were observed among CHIP carriers, who also exhibited higher proportion of high-risk stages (ISS and R-ISS 3) compared to controls. Longitudinal analyses at diagnosis and during follow-up showed a slight increase of VAFs (p = 0.058) for epigenetic (DNMT3A, TET2, and ASXL1) and DNA repair genes (TP53; p = 0.0123). A more stable frequency was observed among other genes, suggesting different temporal dynamics of CH clones. Adverse clinical outcomes, in term of overall and progression-free survivals, were observed in CHIP carriers. These patients also exhibited weakened immune T-cells and enhanced frailty, predicting greater toxicity and consequently shorter event-free survival. Finally, correlation analysis identified platelets count as biomarker for higher VAF among CHIP carriers, regardless of the specific variant. Overall, our study highlights specific biological and clinical features, paving the way for the development of tailored strategies for MM patients carrying CHIP.

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.

Emerging insights into epigenetics and hematopoietic stem cell trafficking in age-related hematological malignancies

BACKGROUND

Hematopoiesis within the bone marrow (BM) is a complex and tightly regulated process predominantly influenced by immune factors. Aging, diabetes, and obesity are significant contributors to BM niche damage, which can alter hematopoiesis and lead to the development of clonal hematopoiesis of intermediate potential (CHIP). Genetic/epigenetic alterations during aging could influence BM niche reorganization for hematopoiesis or clonal hematopoiesis. CHIP is driven by mutations in genes such as Tet2, Dnmt3a, Asxl1, and Jak2, which are associated with age-related hematological malignancies.

OBJECTIVE

This literature review aims to provide an updated exploration of the functional aspects of BM niche cells within the hematopoietic microenvironment in the context of age-related hematological malignancies. The review specifically focuses on how immunological stressors modulate different signaling pathways that impact hematopoiesis.

METHODS

An extensive review of recent studies was conducted, examining the roles of various BM niche cells in hematopoietic stem cell (HSC) trafficking and the development of age-related hematological malignancies. Emphasis was placed on understanding the influence of immunological stressors on these processes.

RESULTS

Recent findings reveal a significant microheterogeneity and temporal stochasticity of niche cells across the BM during hematopoiesis. These studies demonstrate that niche cells, including mesenchymal stem cells, osteoblasts, and endothelial cells, exhibit dynamic interactions with HSCs, significantly influenced by the BM microenvironment as the age increases. Immunosurveillance plays a crucial role in maintaining hematopoietic homeostasis, with alterations in immune signaling pathways contributing to the onset of hematological malignancies. Novel insights into the interaction between niche cells and HSCs under stress/aging conditions highlight the importance of niche plasticity and adaptability.

CONCLUSION

The involvement of age-induced genetic/epigenetic alterations in BM niche cells and immunological stressors in hematopoiesis is crucial for understanding the development of age-related hematological malignancies. This comprehensive review provides new insights into the complex interplay between niche cells and HSCs, emphasizing the potential for novel therapeutic approaches that target niche cell functionality and resilience to improve hematopoietic outcomes in the context of aging and metabolic disorders.

NOVELTY STATEMENT

This review introduces novel concepts regarding the plasticity and adaptability of BM niche cells in response to immunological stressors and epigenetics. It proposes that targeted therapeutic strategies aimed at enhancing niche cell resilience could mitigate the adverse effects of aging, diabetes, and obesity on hematopoiesis and clonal hematopoiesis. Additionally, the review suggests that understanding the precise temporal and spatial dynamics of niche-HSC interactions and epigenetics influence may lead to innovative treatments for age-related hematological malignancies.

Association Between Clonal Hematopoiesis of Indeterminate Potential and Brain β-Amyloid Deposition in Korean Patients With Cognitive Impairment

Few studies have focused on the association between clonal hematopoiesis of indeterminate potential (CHIP) and β-amyloid (Aβ) deposition in the brain, which causes Alzheimer's disease. We aimed to investigate the potential role of CHIP in brain Aβ deposition in Korean patients. We enrolled 58 Korean patients over 50 yrs of age with cognitive impairment who underwent brain Aβ positron emission tomography. We explored CHIP in their peripheral blood using deep-targeted next-generation sequencing. Irrespective of the presence or absence of brain Aβ deposition, mutations in DNMT3A and the C:G>T:A single-nucleotide variants were identified as the primary characteristics, which reflect aged hematopoiesis in the study population. Multivariate logistic regression revealed that the presence of CHIP was not associated with brain Aβ deposition. As both CHIP and brain Aβ deposition are associated with aging, further research is required to elucidate their possible interplay.

The emerging role of clonal haematopoiesis in the pathogenesis of dilated cardiomyopathy

The increased sensitivity of novel DNA sequencing techniques has made it possible to identify somatic mutations in small circulating clones of haematopoietic stem cells. When the mutation affects a 'driver' gene, the mutant clone gains a competitive advantage and has the potential to expand over time, a phenomenon referred to as clonal haematopoiesis (CH), which is emerging as a new risk factor for various non-haematological conditions, most notably cardiovascular disease (e.g. heart failure). Dilated cardiomyopathy (DCM) is a form of non-ischaemic heart failure that is characterized by a heterogeneous aetiology. The first evidence is arising that CH plays an important role in the disease course in patients with DCM, and a strong association of CH with multiple aetiologies of DCM has been described (e.g. inflammation, chemotherapy, and atrial fibrillation). The myocardial inflammation induced by CH may be an important trigger for DCM development for an already susceptible heart, e.g. in the presence of genetic variants, environmental triggers, and comorbidities. Studies investigating the role of CH in the pathogenesis of DCM are expected to increase rapidly. To move the field forward, it will be important to report the methodology and results in a standardized manner, so results can be combined and compared. The accurate measurement of CH in patients with DCM can provide guidance of specific (anti-inflammatory) therapies, as mutations in the CH driver genes prime the inflammasome pathway.

Experimental TET2 Clonal Hematopoiesis Predisposes to Renal Hypertension Through an Inflammasome-Mediated Mechanism

BACKGROUND

Hypertension incidence increases with age and represents one of the most prevalent risk factors for cardiovascular disease. Clonal events in the hematopoietic system resulting from somatic mutations in driver genes are prevalent in elderly individuals who lack overt hematologic disorders. This condition is referred to as age-related clonal hematopoiesis (CH), and it is a newly recognized risk factor for cardiovascular disease. It is not known whether CH and hypertension in the elderly are causally related and, if so, what are the mechanistic features.

METHODS

A murine model of adoptive bone marrow transplantation was employed to examine the interplay between Tet2 (ten-eleven translocation methylcytosine dioxygenase 2) clonal hematopoiesis and hypertension.

RESULTS

In this model, a subpressor dose of Ang II (angiotensin II) resulted in elevated systolic and diastolic blood pressure as early as 1 day after challenge. These conditions led to the expansion of Tet2-deficient proinflammatory monocytes and bone marrow progenitor populations. Tet2 deficiency promoted renal CCL5 (C-C motif ligand 5) chemokine expression and macrophage infiltration into the kidney. Consistent with macrophage involvement, Tet2 deficiency in myeloid cells promoted hypertension when mice were treated with a subpressor dose of Ang II. The hematopoietic Tet2-/- condition led to sodium retention, renal inflammasome activation, and elevated levels of IL (interleukin)-1β and IL-18. Analysis of the sodium transporters indicated NCC (sodium-chloride symporter) and NKCC2 (Na+-K+-Cl- cotransporter 2) activation at residues Thr53 and Ser105, respectively. Administration of the NLRP3 (NLR family pyrin domain containing 3) inflammasome inhibitor MCC950 reversed the hypertensive state, sodium retention, and renal transporter activation.

CONCLUSIONS

Tet2-mediated CH sensitizes mice to a hypertensive stimulus. Mechanistically, the expansion of hematopoietic Tet2-deficient cells promotes hypertension due to elevated renal immune cell infiltration and activation of the NLRP3 inflammasome, with consequences on sodium retention. These data indicate that carriers of TET2 CH could be at elevated risk for the development of hypertension and that immune modulators could be useful in treating hypertension in this patient population.

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.

EASIX (endothelial activation and stress index) predicts mortality in patients with coronary artery disease

BACKGROUND

Coronary interventions reduce morbidity and mortality in patients with acute coronary syndrome. However, the risk of mortality for patients with coronary artery disease (CAD) additionally depends on their systemic endothelial health status. The 'Endothelial Activation and Stress Index' (EASIX) predicts endothelial complications and survival in diverse clinical settings.

OBJECTIVE

We hypothesized that EASIX may predict mortality in patients with CAD.

METHODS

In 1283 patients undergoing coronary catheterization (CC) and having a diagnosis of CAD, EASIX was measured within 52 days (range - 1 year to - 14 days) before CC and correlated with overall survival. In an independent validation cohort of 1934 patients, EASIXval was measured within 174 days (+ 28 days to + 11 years) after CC.

RESULTS

EASIX predicted the risk of mortality after CC (per log2: hazard ratio (HR) 1.29, 95% confidence interval: [1.18-1.41], p < 0.001) in multivariable Cox regression analyses adjusting for age, sex, a high-grade coronary stenosis ≥ 90%, left ventricular ejection fraction, arterial hypertension and diabetes. In the independent cohort, EASIX correlated with EASIXval with rho = 0.7. The long-term predictive value of EASIXval was confirmed (per log2: HR 1.53, [1.42-1.64], p < 0.001) and could be validated by integrated Brier score and concordance index. Pre-established cut-offs (0.88-2.32) associated with increased mortality (cut-off 0.88: HR training: 1.63; HR validation: 1.67, p < 0.0001 and cut-off 2.32: HR training: 3.57; HR validation: 4.65, p < 0.0001).

CONCLUSIONS

We validated EASIX as a potential biomarker to predict death of CAD patients, irrespective of the timing either before or after catheterization.

Parkinson's disease is associated with clonal hematopoiesis with TET2 mutation

Clonal hematopoiesis of indeterminate potential (CHIP), a premalignant expansion of mutated hematopoietic stem cells, is linked to immune alterations. Given the role of neuroinflammation and immune dysfunction in Parkinson's disease (PD), we hypothesized a connection between CHIP and PD. We analyzed peripheral blood DNA from 341 PD, 92 isolated REM sleep behavior disorder (iRBD) patients, and 5003 controls using targeted sequencing of 24 genes associated with hematologic neoplasms. PD cases were classified by clinical progression mode: fast, slow, and typical. Using multivariable logistic regression models, CHIP prevalence was assessed against controls with a 1.0% variant allele fraction threshold. CHIP with TET2 mutations was more prevalent in PD than controls (aOR 1.75, 95% CI 1.11-2.77, p = 0.017), particularly in the fast motor progression subgroup (aOR 3.19, p = 0.004). No distinct associations were observed with iRBD. PD is linked to increased odds of CHIP with TET2 mutations, suggesting immune dysregulation in PD pathophysiology.

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.

Clonal hematopoiesis of indeterminate potential and cardiovascular disease: Pathogenesis, clinical presentation, and future directions

Clonal hematopoiesis of indeterminate potential (CHIP) is a well-studied phenomenon in hematologic malignancies. With advancements in gene sampling and analysis and the use of large cohort studies, CHIP has recently been linked to cardiovascular disease (CVD). The relationship between CHIP and CVD appears to be bidirectional, with traditional risk factors for cardiovascular disease increasing the mutation burden in CHIP, and CHIP itself effecting the incidence or prognosis of a variety of CVD. The purpose of this review is to understand the epidemiology, risk factors, and pathogenesis of CHIP in the context of various CVD conditions.

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.

Invasive Assessment of Coronary Artery Disease in Clonal Hematopoiesis of Indeterminate Potential

BACKGROUND

Clonal hematopoiesis of indeterminate potential (CHIP) occurs due to acquired mutations in bone marrow progenitor cells. CHIP confers a 2-fold risk of atherosclerotic cardiovascular disease. However, there are limited data regarding specific cardiovascular phenotypes. The purpose of this study was to define the coronary artery disease phenotype of the CHIP population-based on coronary angiography.

METHODS

We recruited 1142 patients from the Vanderbilt University Medical Center cardiac catheterization laboratory and performed DNA sequencing to determine CHIP status. Multivariable logistic regression models and proportional odds models were used to assess the association between CHIP status and angiography phenotypes.

RESULTS

We found that 18.4% of patients undergoing coronary angiography had a CHIP mutation. Those with CHIP had a higher risk of having obstructive left main (odds ratio, 2.44 [95% CI, 1.40-4.27]; P=0.0018) and left anterior descending (odds ratio, 1.59 [1.12-2.24]; P=0.0092) coronary artery disease compared with non-CHIP carriers. We additionally found that a specific CHIP mutation, ten eleven translocase 2 (TET2), has a larger effect size on left main stenosis compared with other CHIP mutations.

CONCLUSIONS

This is the first invasive assessment of coronary artery disease in CHIP and offers a description of a specific atherosclerotic phenotype in CHIP wherein there is an increased risk of obstructive left main and left anterior descending artery stenosis, especially among TET2 mutation carriers. This serves as a basis for understanding enhanced morbidity and mortality in CHIP.

Selective advantage of mutant stem cells in human clonal hematopoiesis is associated with attenuated response to inflammation and aging

Clonal hematopoiesis (CH) arises when hematopoietic stem cells (HSCs) acquire mutations, most frequently in the DNMT3A and TET2 genes, conferring a competitive advantage through mechanisms that remain unclear. To gain insight into how CH mutations enable gradual clonal expansion, we used single-cell multi-omics with high-fidelity genotyping on human CH bone marrow (BM) samples. Most of the selective advantage of mutant cells occurs within HSCs. DNMT3A- and TET2-mutant clones expand further in early progenitors, while TET2 mutations accelerate myeloid maturation in a dose-dependent manner. Unexpectedly, both mutant and non-mutant HSCs from CH samples are enriched for inflammatory and aging transcriptomic signatures, compared with HSCs from non-CH samples, revealing a non-cell-autonomous effect. However, DNMT3A- and TET2-mutant HSCs have an attenuated inflammatory response relative to wild-type HSCs within the same sample. Our data support a model whereby CH clones are gradually selected because they are resistant to the deleterious impact of inflammation and aging.

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.

Clonal hematopoiesis driven by mutated DNMT3A promotes inflammatory bone loss

Clonal hematopoiesis of indeterminate potential (CHIP) arises from aging-associated acquired mutations in hematopoietic progenitors, which display clonal expansion and produce phenotypically altered leukocytes. We associated CHIP-DNMT3A mutations with a higher prevalence of periodontitis and gingival inflammation among 4,946 community-dwelling adults. To model DNMT3A-driven CHIP, we used mice with the heterozygous loss-of-function mutation R878H, equivalent to the human hotspot mutation R882H. Partial transplantation with Dnmt3aR878H/+ bone marrow (BM) cells resulted in clonal expansion of mutant cells into both myeloid and lymphoid lineages and an elevated abundance of osteoclast precursors in the BM and osteoclastogenic macrophages in the periphery. DNMT3A-driven clonal hematopoiesis in recipient mice promoted naturally occurring periodontitis and aggravated experimentally induced periodontitis and arthritis, associated with enhanced osteoclastogenesis, IL-17-dependent inflammation and neutrophil responses, and impaired regulatory T cell immunosuppressive activity. DNMT3A-driven clonal hematopoiesis and, subsequently, periodontitis were suppressed by rapamycin treatment. DNMT3A-driven CHIP represents a treatable state of maladaptive hematopoiesis promoting inflammatory bone loss.

Clonal hematopoiesis of indeterminate potential in patients with immunoglobulin light-chain AL amyloidosis

ABSTRACT

Immunoglobulin light-chain (AL) amyloidosis is characterized by the deposition of misfolded monoclonal free light chains, with cardiac complications accounting for patient mortality. Clonal hematopoiesis of indeterminate potential (CHIP) has been associated with worse cardiovascular outcomes in the general population. Its significance in AL amyloidosis remains unclear. We collected clinical information and outcome data on 76 patients with a diagnosis of AL amyloidosis who underwent deep targeted sequencing for myeloid neoplasia-associated mutations between April 2018 and August 2023. Variant allele frequency was set at 2% to call CHIP-associated mutations. CHIP mutations were present in patients with AL amyloidosis at a higher frequency compared with age-matched control individuals. Sixteen patients (21%) had at least 1 CHIP mutation. DNMT3A was the most frequent mutation (7/16; 44%). Compared with patients without CHIP, patients with CHIP had a higher prevalence of t(11;14) translocation (69% vs 25%, respectively; P = .004). Furthermore, among patients with renal involvement, those with CHIP had a lower Palladini renal stage (P = .001). At a median follow-up of 32.5 months, the presence of CHIP was not associated with worse overall survival or major organ dysfunction progression-free survival. Larger studies and longer follow-up are needed to better define the impact of CHIP in patients with AL amyloidosis.

DNMT3A dysfunction promotes neuroinflammation and exacerbates acute ischemic stroke

Somatic mutations related to clonal hematopoiesis of indeterminate potential (CHIP) are risk factors for stroke. The impact of DNMT3A, the most mutated gene in CHIP, on clinical functional outcomes of acute ischemic stroke (AIS) remains unclear. In a well-characterized cohort of 8524 ischemic stroke patients, we demonstrated that DNMT3A-driven CHIP was significantly associated with neurological disability in these patients. With a stroke mouse model of transient middle cerebral artery occlusion (tMCAO), we demonstrated that DNMT3A protein levels in the brain penumbra increased. The DNMT3A inhibitor RG108 administration amplified neutrophil proliferation in the blood, promoted neutrophil infiltration into the brain penumbra, and exaggerated proinflammatory activation in tMCAO male mice. DNMT3A inhibition also significantly increased infarct volume and worsened neurobehavioral function in tMCAO male mice. In conclusion, DNMT3A somatic mutations are associated with worsened neurological disability in some patients with AIS, potentially through increased neutrophil proliferation and infiltration in the ischemic brain region. These findings suggest a possible mechanism for proinflammatory activation and tissue damage in the affected brain tissue, highlighting the need for further research in this area.

Clonal hematopoiesis of indeterminate potential contributes to accelerated chronic kidney disease progression

Background

Clonal hematopoiesis of indeterminate potential (CHIP) is a common inflammatory condition of aging that causes myriad end-organ damage. We have recently shown associations for CHIP with acute kidney injury and with kidney function decline in the general population, with stronger associations for CHIP driven by mutations in genes other than DNMT3A (non- DNMT3A CHIP). Longitudinal kidney function endpoints in individuals with pre-existing chronic kidney disease (CKD) and CHIP have been examined in two previous studies, which reported conflicting findings and were limited by small sample sizes.

Methods

In this study, we examined the prospective associations between CHIP and CKD progression events in four cohorts of CKD patients (total N = 5,772). The primary outcome was a composite of 50% kidney function decline or kidney failure. The slope of eGFR decline was examined as a secondary outcome. Mendelian randomization techniques were then used to investigate potential causal effects of CHIP on eGFR decline. Finally, kidney function was assessed in adenine-fed CKD model mice having received a bone marrow transplant recapitulating Tet2 -CHIP compared to controls transplanted wild-type bone marrow.

Results

Across all cohorts, the average age was 66.4 years, the average baseline eGFR was 42.6 ml/min/1.73m 2 , and 24% had CHIP. Upon meta-analysis, non- DNMT3A CHIP was associated with a 59% higher relative risk of incident CKD progression (HR 1.59, 95% CI: 1.02-2.47). This association was more pronounced among individuals with diabetes (HR 1.29, 95% CI: 1.03-1.62) and with baseline eGFR ≥ 30 ml/min/1.73m (HR 1.80, 95% CI: 1.11-2.90). Additionally, the annualized slope of eGFR decline was steeper among non- DNMT3A CHIP carriers, relative to non-carriers (β -0.61 ± 0.31 ml/min/1.73m 2 , p = 0.04). Mendelian randomization analyses suggested a causal role for CHIP in eGFR decline among individuals with diabetes. In a dietary adenine mouse model of CKD, Tet2 -CHIP was associated with lower GFR as well as greater kidney inflammation, tubular injury, and tubulointerstitial fibrosis.

Conclusion

Non- DNMT3A CHIP is a potentially targetable novel risk factor for CKD progression.

Aortic disease and cardiomyopathy in patients with a novel DNMT3A gene variant causing Tatton-Brown-Rahman syndrome

Tatton-Brown-Rahman syndrome (TBRS) is a rare congenital genetic disorder caused by autosomal dominant pathogenic variants in the DNA methyltransferase DNMT3A gene. Typical TBRS clinical features are overgrowth, intellectual disability, and minor facial anomalies. However, since the syndrome was first described in 2014, a widening spectrum of abnormalities is being described. Cardiovascular abnormalities are less commonly reported but can be a major complication of the syndrome. This article describes a family of three individuals diagnosed with TBRS in adulthood and highlights the variable expression of cardiovascular features. A 34-year-old proband presented with progressive aortic dilatation, mitral valve (MV) regurgitation, left ventricular (LV) dilatation, and ventricular arrhythmias. The affected family members (mother and brother) were diagnosed with MV regurgitation, LV dilatation, and arrhythmias. Exome sequencing and computational protein analysis suggested that the novel familial DNMT3A mutation Ser775Tyr is located in the methyltransferase domain, however, distant from the active site or DNA-binding loops. Nevertheless, this bulky substitution may have a significant effect on DNMT3A protein structure, dynamics, and function. Analysis of peripheral blood cfDNA and transcriptome showed shortened mononucleosome fragments and altered gene expression in a number of genes related to cardiovascular health and of yet undescribed function, including several lncRNAs. This highlights the importance of epigenetic regulation by DNMT3A on cardiovascular system development and function. From the clinical perspective, we suggest that new patients diagnosed with congenital DNMT3A variants and TBRS require close examination and follow-up for aortic dilatation and valvular disease because these conditions can progress rapidly. Moreover, personalized treatments, based on the specific DNMT3A variants and the different pathways of their function loss, can be envisioned in the future.