Clonal hematopoiesis of unknown potential and cardiovascular disease – literature review

Б  том ХXXI, 2025, № 3 ДРУЖЕСТВО НА КАРДИОЛОЗИТЕ В БЪЛГАРИЯ ОБЗОРИ REVIEWS CLONAL HEMATOPOIESIS OF UNKNOWN POTENTIAL AND CARDIOVASCULAR CLONAL HEMATOPOIESIS OF UNKNOWN POTENTIAL AND CARDIOVASCULAR DISEASE – LITERATURE REVIEW DISEASE – LITERATURE REVIEW G. Goranov1, V. Goranova-Marinova2 1Department of Invasive Cardiology, Cardiology Section, UMHAT “Sveti Georgi”, First Department of Internal Medicine, Medical University – Plovdiv 2Clinic of Hematology, Section of Hematology, UMHAT “Sveti Georgi”, First Department of Internal Medicine, Medical University – Plovdiv КЛОНАЛНА ХЕМОПОЕЗА С НЕИЗВЕСТЕН ПОТЕНЦИАЛ И СЪРДЕЧНО-СЪДОВИ КЛОНАЛНА ХЕМОПОЕЗА С НЕИЗВЕСТЕН ПОТЕНЦИАЛ И СЪРДЕЧНО-СЪДОВИ ЗАБОЛЯВАНИЯ – ЛИТЕРАТУРЕН ОБЗОР ЗАБОЛЯВАНИЯ – ЛИТЕРАТУРЕН ОБЗОР Г. Горанов1, В. Горанова-Маринова2 1Отделение по инвазивна кардиология, Секция по кардиология, УМБАЛ „Свети Георги“; Първа катедра по вътрешни болести, Медицински университет – Пловдив 2Клиника по хематология, Секция по хематология, УМБАЛ „Свети Георги“; Първа катедра по вътрешни болести, Медицински университет – Пловдив Abstract. Somatic mutations in hematopoietic stem cells (HSCs) are an inevitable part of human aging. When these mutations reach a certain variant allele frequency (VAF), they may confer a proliferative advantage to mutated clones, leading to clonal hematopoiesis. Once the HSCs generate over 10¹⁰-10¹² mutated cells, they can initiate various myeloid or lymphoid malignancies. In cases where the VAF exceeds 2% (roughly 10⁴ mutated blood cells) but without clinical evidence of hematologic cancer, the condition is termed clonal hematopoiesis of indeterminate potential (CHIP). Numerous studies have identifi ed that CHIP is frequently driven by mutations in genes implicated in hematologic malignancies, most notably TET2, DNMT3A, and JAK2. CHIP has also been strongly linked to cardiovascular diseases, particularly atherosclerosis. This dual role highlights a shared pathogenesis between cardiovascular and hematologic disorders through mutations in HSCs. CHIP-associated monocytes exhibit a pro-infl ammatory phenotype, activating infl ammasomes and overexpressing cytokines such as interleukin (IL)-1β and IL-6, as well as chemokines like Cxcl1-3 and Pf4. This leads to a chronic infl ammatory loop that contributes to endothelial dysfunction and atherosclerosis. Current data suggest that CHIP poses a cardiovascular risk comparable to traditional risk factors. Ongoing research continues to uncover the complex mechanisms underlying this association. Key words: somatic mutations, clonal hematopoiesis of undetermined potential, TET2, DNMT3A, JAK2 V617F, cardiovascular diseases, heart failure Address for correspondence: Georgi Goranov, MD, e-mail: [email protected] Резюме:Соматичните мутации в хемопоетичните стволови клетки (HSC) са неизбежна част от биологичното стареене на човека. При достигане на определена вариантна алелна честота (VAF) някои от тези мутации осигуряват селективно предимство и стимулират пролиферацията на клонове – феномен, известен като клонална хемопоеза (КХ). Натрупването на над 10¹⁰-10¹² мутирали клетки може да доведе до развитие на миелоили лимфопролиферативни неоплазии. Когато VAF е ≥ 2% (приблизително 10⁴ клетки) и липсват данни за хематологично злокачествено заболяване, състоянието се определя като клонална хемопоеза с неопределен потенциал (CHIP). Най-често се засягат гени, свързани с предлевкемични промени – TET2, DNMT3A и JAK2. Интересно е, че CHIP се асоциира не само с хематологични, но и със сърдечно-съдови заболявания, особено атеросклероза. Модифицираните моноцити активират инфламозоми и засилват секрецията на провъзпалителни медиатори – interleukin (IL)-1β, IL-6 и хемокини като Cxcl1-3 и Pf4, което води до хронично възпаление и съдова увреда. Така се оформя самоподдържащ This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. doi: 10.3897/bgcardio.31.e165714 G. Goranov, V. Goranova-Marinova 14 I Two fundamentally diverse groups of diseases – cardiovascular and malignant blood neoplasia – can be pathogenetically linked through the same genetic mutations in pluripotent hematopoietic stem cells (HSC). Mutations in stem and progenitor cells most often aff ect genes responsible for specifi c signalling cascades regulating diff erentiation, proliferation, maturation, and apoptosis, i.e. biology, lineage development, and function of individual cell lines. Each mutation triggers unique pathogenetic mechanisms leading to a specifi c phenotypic manifestation. Depending on the abundance of the mutagenic burden, i.e. variant allele frequency (VAF), the mutated clone can gain a competitive advantage by proliferating uncontrollably with suppressed apoptosis. The cell pool with such biological superiority is the result of the so-called clonal haematopoiesis (CH) caused by multiple somatic mutations and epigenetic eff ects in the parent cell, which reproduces through identical daughter copies (clones). When CH “produces” more than 1010-12 mutated cells various myeloand lymphoproliferative malignant blood neoplasia are triggered. At a VAF of at least 2%, which corresponds to about 104 mutated cells and in the absence of data on hematologic malignancy, CH is designated as clonal haematopoiesis of indeterminate potential (CHIP) [1]. This category also includes the so-called clonal cytopenia of undeterminate signifi - cance without myelodysplastic features (CCUS) [2]. CHIP occurs in healthy individuals and increases tenfold with age, in which case the term age-related clonal haematopoiesis is also used [2, 3]. Modern genetic technology has allowed for the leading driver mutations of CHIP to be established. These include mutations commonly associated with certain acute and chronic malignant hemopathies [4, 5]. In most studies, CHIP represents an optional indefi nite-duration pre-phase of hematologic malignancies, with important pathogenetic signifi cance to a number of non-hematologic conditions and above all to atherogenesis [5]. Over the last decade, an increasing number of publications have indicated a surprisingly high correlation between CHIP and all-cause mortality. CHIP has also been associated with a signifi cantly elevated risk of adverse events in patients with cardiovascular diseases (CVD). Contemporary evidence suggests that CHIP is an important risk factor for coronary artery disease (CAD), comparable in signifi cance to hypertension, diabetes, overweight, hypercholesterolemia, smoking, chronic obstructive pulmonary disease (COPD), peripheral artery disease (PAD), chronic kidney disease (CKD). The correlation between CHIP, aging, atherosclerosis and above all CAD is yet to be determined as evidence is currently scarce. The mechanisms through which CHIP triggers or modulates atherogenesis are not clearly understood and so is its impact on real life clinical practice. First reports on CHIP In 1994, Fey MF fi rst established CH in non-random inactivation of the X chromosome, which is reproducibly preserved during mitotic division [6]. In 2012, Busque et al. confi rmed the presence of CH by establishing mutation of the TET2 gene in about 5% of adult women [7]. The existence of an initial driver mutation – AML1/ETO translocation as a part of a HSC mutation was reported by T. Miyamoto et al. during remission in a case of acute myeloid leukemia (AML) [8]. Despite the 10-fold higher risk, malignant haematological transformation is an exceedingly rare phenomenon, requiring multiple additional gene mutations, i.e. most CHIP carriers will not develop malignant hemopathy throughout their lives. Prevalence It is assumed that HSCs are about 1/100,000 in the adult bone marrow, which corresponds to 50,000200,000 cells. Of these, about 1% circulate in the peripheral blood, have the ability to self-renew to the highest degree and are identifi ed by the surface marker CD34 [9]. With strictly determined apoptosis duration, individual cell lines produce about 200 billion erythrocytes, 100 billion platelets and 60 billion neutrophils daily. It has been estimated that each HSC acquires 1 exonic mutation/10 years of life, 0.13 ± 0.02 exonic mutations/year of life or about 5 coding gene mutations in each stem cell by the age of 50 years [10]. In an adult individual aged 70 years, this corresponds to се възпалителен цикъл, в който се включват и традиционни рискови фактори. В този контекст CHIP се разглежда като нов, независим рисков фактор за исхемична болест на сърцето, съпоставим по значимост с артериалната хипертония, захарния диабет и тютюнопушенето. Макар наличните проучвания да са все още в ранен етап връзката между CHIP и атерогенезата поражда нарастващ научен и клиничен интерес. Ключови думи:соматични мутации, клонална хематопоеза с неопределен потенциал, TET2, DNMT3A, JAK2 V617F, сърдечно-съдови заболявания, сърдечна недостатъчност Адрес за кореспонденция:д-р Георги Горанов, e-mail: [email protected] 15 Clonal hematopoiesis of unknown potential and cardiovascular disease... 350,000-1,400,000 gene mutations or an average of 70 mutations per gene [11]. This leads to the conclusion that, with advancing age, mosaicism with diff erent genotypes could be found in every individual [12, 13]. Reported prevalence of CHIP varies signifi cantly depending on the literature source. Jaiswal S et al. performed complete sequencing of DNA exon for somatic mutations in 160 genes (involved in malignant hemopathies) in 17,182 individuals and found the following: detectable clones are rare in individuals under 40 years of age - less than 1%, at the age of 70-79 years they are 9.5%, at 80-89 years – 11.7%, and from 90-108 years – 18.5% [12]. Using deep-corrected targeted sequencing with a VAF ≥ 0.5%, K. C. Kiefer et al. found CHIP with at least one mutation in 87% of the studied cohort of 399 patients. The incidence of CHIP increased with age: in the range of 50-59 years – 81.6%, at 60-69 years – 90.7%, at 70-79 years – 88.8%, and 100% in patients above 80 years (p < 0.026) [5]. Similarly, A. L. Young et al. found stable clonal mutations in 93% of studied 50-60-year-old individuals with a VAF ≥ 0.01% by targeted sequencing with error correction [13]. Fig. 1. Prevalence of СНIP depending on age and genetic method used [ Jaiswal S, N Engl J Med, 2014] On the one hand, these examples show, that CHIP with VAF ≥ 0.5% is about twice as common a phenomenon as previously reported in literature. On the other hand, the prevalence of CHIP is not a function of age alone, but rather of the sensitivity of the genetic methods used (Fig. 1). Mutational spectrum in CHIP The mechanisms leading to the occurrence of mutational genomic disorders in CHIP are mainly loss of function or truncation of alleles in various epigenetic regulatory genes. According to literature, the range of genomic defects resulting in stable clonal selection is extremely wide and increases depending on the genetic methods and the availability of deep sequencing with low VAF. Kiefer K.C. and col. found that the most common mutations occur in driver genes: DNA (cytosine-5)-methyltransferase 3A – DNMT3A (226), followed by mutations in the genes Tet Methylcytosine Dioxygenase 2 – TET2 (133), BCL6 Corepressor Like 1 – BCORL1 (78), ATRX (54), STAG2 (50) and in 43 other genes. Of the 399 patients, 21% had 1 mutation, 47% had from 2 to 4 mutations, and 19% from 5 to 12 mutations [5]. In reality, however, CHIP of suffi cient clone size results from mutations in an extremely limited number of genes that form the so-called “risk panel.” About 2/3 of clinically signifi cant mutations occur in 3-4 genes: DNMT3A, TET2, additional sex combs like 1 – ASXL1, and janus kinase 2 – JAK2, the pathophysiological signifi cance of which is discussed below. CHIP – a new genetic biomarker and risk factor for cardiovascular disease In 4 studies, including a total of 4794 cases and 3537 controls, Jaiswal et al. were the fi rst to fi nd that CHIP carriers had a 3.3-fold higher risk of coronary artery calcifi cation above 615 Agatston units (computed coronary tomography) without incidental coronary artery disease and 1.8-fold higher risk of subsequent Fig. 2. CHIP and most common mutations found in 3 studies [by Yura Y et al, 2020] G. Goranov, V. Goranova-Marinova 16 CAD (p = 0.03), a 1.9-fold higher risk of coronary artery disease and a 4-fold higher risk of early myocardial infarction. The individual risk is proportional to the mutagenic burden (VAF variations) and is individually associated with single mutations in driver genes, but also with a wide variety of other mutations, as proven by advanced technology [12, 14, 15]. In the last 10 years, a constantly increasing number of studies have confi rmed the signifi cant relationship between CHIP and cardiovascular outcomes: higher all-cause mortality, higher risk of ischemic stroke, doubled risk of venous thrombosis, higher hospital mortality, higher mortality from CAD, higher midterm overall mortality after successful transcatheter aortic valve implantation (TAVI), more frequent systolic and diastolic dysfunction, progression of HF and cardiogenic shock, more frequent unprovoked pulmonary thromboembolism, absolute arrhythmia, aortic aneurysm. Similar associations, proven through various multivariate statistical analyses, present CHIP as a new independent, prognostic risk factors for CVD, equal in signifi cance to conventional risk factors (Fig. 3). Fig. 3 CHIP, predisposing factors and cardiovascular disease [A. Stein, Basic Research in Cardiology, 2022] Factors facilitating CHIP The most common mechanism enabling CHIP mutations is spontaneous deamination with the replacement of cytosine by thymidine, a major phenomenon of aging due to reduced effi ciency of DNA error correction. CHIP is an almost inevitable consequence of aging, and age is the strongest risk factor for its manifestation [16]. Anna Stein et al. analysed a number of studies and identifi ed the following factors facilitating CHIP: male gender, smoking, chronic infl ammatory and autoimmune diseases, Human Immunodefi ciency Virus infection, previous chemotherapy and radiotherapy, unhealthy diet, changes in the microbiome, family predisposition (Fig. 3) [17]. Presumed pathogenetic relationship between CHIP and atherogenesis and cardiovascular disease Theoretical knowledge of the mutation spectrum in CHIP and its signifi cance is still in an early stage of research. Only the most common driver genes (TET2, DNMT3A, JAK2 and ASXL1) have proved to play a pathogenetic role in CHIP mutations. Many other genes, identifi ed through modern genetic methods, demonstrate mere statistical association and have no proven signifi cance. CHI P with TET2 mutations The fi rst experimental mouse models with Tet2 knockout by K. Moran-Crusio (2011) found increased self-renewal of HSCs with predominantly myeloid differentiation, splenomegaly, and extramedullary haematopoiesis [18]. Considering the high frequency of TET2-mediated CHIP in atherosclerotic CVD, experimental mouse models with a relatively uniform design were developed by two groups of authors in 2017: lethally irradiated mice with low-density lipoprotein receptor defi ciency Ldlr1−/− were transplanted with TET2−/− and TET2+/− cells and subjected to a high-fat diet. In a fundamental, well-designed, and scientifi cally substantiated study, J. J. Fuster et al. obtained results with theoretical signifi cance and direction for future investigation [19]: 1. In TET2−/− transplanted mice (resembling human CHIP with TET2 mutations), haematopoiesis increases with a predominance of the myeloid population, and an increased number of monocytes is noted. 2. TET2−/− and TET2+/− defi - cient mice develop 60% larger atherosclerotic plaques in the aortic root than the control groups; there are no changes in the smooth muscle endothelium, necrotic nuclei, cell proliferation in the plaques, as well as abnormal apoptosis. 3. TET2−/− haematopoiesis is characterised by proliferation of the proatherogenic macrophage population in the atherosclerotic intima, i.e. phenotypically altered macrophages are probably the key factor for accelerated atherogenesis. 4. TET2−/− defi ciency is a negative transcriptional regulator of the infl ammatory response, i.e. it stimulates infl ammatory processes. In TET2−/− macrophages increased transcription of genes encoding cytokines, chemokines and signaling molecules results in expression of pro-infl ammatory factors. 1Ldlr – Low-Density Lipoprotein Receptor (gene, mouse model) 17 Clonal hematopoiesis of unknown potential and cardiovascular disease... 5. Minimizing the infl uence of TET2 defi ciency by humoral agents – oxLDL, TNF and interferon gamma (IFN-γ) resulted in a signifi cant decrease in the expression of cytokines and chemokines, with the exception of interleukin (IL)-1β, which was signifi cantly elevated in TET2−/− macrophages. A 2-fold increase in the expression of IL-1β transcripts in the aortic arch of mice was also noted. 6. Cell cultures with macrophages overexpressing mutant TET2 have reduced HDAC2-mediated histone deacetylation, i.e. loss of TET2 function modulates IL1β expression in macrophages, regardless of its catalytic activity. 7. TET2 defi ciency aff ects IL-1β secretion by activating the NLRP33 infl ammasome and increasing its main component – caspase-1 (stimulating the cleavage of pro-IL-1β to an active form). The authors supported their thesis by blocking the NLRP3 infl ammasome with the MCC950 inhibitor, which led to a decrease in plaque size by about 50%, i.e. MCC950 exhibits a distinct anti-atherogenic eff ect and eliminates the diff erence with controls. 8. In addition to being a key mediator of TET2 defi ciency in CVD the pro-atherogenic IL-1β correlates with increased expression of P-selectin in the aortic endothelium causing increased adhesion of monocytes to the atherosclerotic plaque [19]. Jaiswal S’s team supported the available experimental results and added new evidence for the pathogenetic signifi cance of TET2 defi ciency using a similar mouse model [14]. In their experiment, mice with TET2−/− haematopoiesis developed atherosclerotic lesions in the aortic root of 2 to 2.7-fold greater average size, for the duration of 17 weeks. TET2−/− macrophages increased the transcription of a chemokine gene cluster (Cxcl1, Cxcl2, Cxcl3, Pf4) and of the classical pro-infl ammatory cytokine genes – IL-1β and IL-6, resulting in 2-4-fold elevation of their serum secretion. Another interesting fi nding was the increase in atherogenesis in other tissues – spleen and middle ear xanthomas, accumulation of foam cells and large infl ammatory infi ltrates in the kidneys, liver, and lungs. In 2018, S. Sano and colleagues presented experimental evidence for the association between HF and CHIP with TET2 mutations in two TET2-defi cient mice models [20]. In the fi rst model, chronic ischemia was induced by permanent ligation of the left anterior descending coronary artery, and in the second, by increased pressure from transverse aortic constriction or angiotensin infusion. In both models of HF, TET2 defi ciency worsened cardiac remodelling with increased 2HDAC – Histone Deacetylase 3NOD-, LRRand pyrin domain-containing protein 3 (infl ammasome) hypertrophy, cardiac dysfunction and IL-1β expression. The administration of a selective NLRP3 infl ammasome inhibitor, as in the experiments of Fuster JJ et al, prevented the development of HF and eliminated the diff erences with controls. CHIP with DNMT3A mutation DNMT3A is the most common mutated gene in CHIP. It catalyses DNA methylation and is an important regulator of haematopoiesis and infl ammatory responses. Similar to TET2 defi ciency, DNMT3A−/− or +/− leads to myeloid expansion of haematopoiesis and to the development of myeloid neoplasia in experimental mouse models [21]. Although TET2 and DNMT3A mediate the opposite catalytic reactions, mutations in both genes lead to convergent CHIP phenotypes. To demonstrate a causal relationship between DNMT3A-mediated CHIP and atherogenesis, Rauch et al. used a mouse model similar to the ones described above and established the following: 1. The gene expression profi le was similar to the TET2−/− experimental setups – genes encoding the chemokine cluster Cxcl1, Cxcl2 and Cxcl3 as well as mRNA encoding the main pro-infl ammatory cytokines IL-1β and IL-6 were upregulated. 2. After 9 weeks the average size of atherosclerotic lesions was 40% larger in Dnmt3a−/− mice, compared to controls (p = 0.04). 3. A population of lesional macrophages expressing genetic markers (Mrc1, Lyve1, F13a1), infl ammatory mediators (Cxcl1, Pf4, Ccl2, Ccl7, Ccl8) and transcription factors (Jun, Fos, Egr1) characteristic of macrophages in atherosclerotic plaques was found in Tet2 or Dnmt3a defi ciency [22]. Using a lentiviral vector and the Clustered Regularly Interspaced Short Palindromic Repeats – CRISPR/ Cas9, S. Sano et al. inactivated Tet2 and Dnmt3a in bone marrow cells and then competitively transplanted them. CRISPR-manipulated cells not only proliferated in the bone marrow similar to Tet2-defi cient mouse models, but also mediated pathological cardiac remodelling after angiotensin II infusion, resulting in worsening of cardiac function, and higher levels of fi brosis and infl ammation [23]. CHIP with JAK mutation JAK2 is a potent signal transducer that activates transcription of the signal transducer and activator of transcription (STAT) pathway, regulating the production of proinfl ammatory cytokines. The JAK2 V617F (janus kinase) mutation is prevalent and coincidence in CHIP and myeloproliferative neoplasms (MPN). The JAK2 mutation encodes and triggers 3 MPNs – polycythemia vera (PV), essential thrombocythemia (ET) and primary myelofi brosis (PMF). In JAK2 CHIP the hemogram remains unchanged. JAK2 mutation occurs in about G. Goranov, V. Goranova-Marinova 18 3.1% of the general population and is most signifi cantly associated with the risk of CVD and thrombosis [24]. Early studies of JAK2 mutation in MPN focused on thromboembolic complications, a well-recognized clinical syndrome in PV and ET. JAK2 mutation is a major thrombogenic risk factor with well-known phenotypic thrombogenic diff erences: a 2-fold increase in arterial thrombotic risk in ET and PV and a higher incidence of venous thrombosis in PMF. Interestingly, there was no signifi cant correlation between thromboembolic events and TET2, DNMT3A or ASXL1 mutations (rare in MPN but very common in CHIP). Moreover, in a study on 587 patients conducted by S. Cerquozzi et al., PV with TET2 or ASXL1 mutations was not associated with higher risk for arterial thrombosis [25]. According to Guglielmelli P et al, the ASXL1 mutation in TE reduces the thrombotic risk [26]. The so-called neutrophil extracellular traps (NETs) are of pathogenetic importance for thrombotic complications in MPN [27]. They are the result of stimulated neutrophils, which push out extracellular strands of decondensed DNA in a complex with histones and other neutrophil proteins. In experimental models, O. Wallach et al. demonstrated that JAK2-positive HF is associated with an increased incidence of thrombosis, resulting from increased NET formation with a prothrombotic phenotype in mice. The authors found that overexpressed peptidyl-arginine deiminase 4 (PAD4) is essential for chromatin decondensation in NETs. PAD4 regulates both NET-osis and pathological thrombosis, and NET biomarkers refl ect the activity of the underlying process [28]. In a recent study, Guy A investigated NET-osis in two mouse populations in an experimental model – expressing JAK2V617F in all hematopoietic lineages (as in MNPs) and only in leukocytes. Ex vivo experiments show that JAK2V617F-mutated platelets trigger NET-osis by JAK2V617F-mutated neutrophils, i.e. JAK2V617F neutrophils alone are not a suffi cient stimulus of thrombogenesis, and rather platelets cooperate with neutrophils to promote NET-osis in vivo [29]. Beyond the prothrombogenic mechanism discussed above, JAK2-mediated CHIP has been implicated in atherogenesis, increased cardiac fi brosis, and pathological remodelling through activation of the JAKSTAT signalling cascade. Sano et al. performed competitive JAK2 transgenic bone marrow transplantation in irradiated wild mice. They restricted JAK2 expression to neutrophils, monocytes, and macrophages with JAK2-specifi c transduction by lentivirus. The model approximates CHIP with no changes in blood cell counts or other neoplastic features. After coronary artery ligation with induction of infarction or increased pre-load via aortic constriction, the authors demonstrated that JAK2 expression in mice leads to enhanced infl ammatory STAT signalling, increased levels of the infl ammatory cytokines IL-1β, IL-6, tumor necrosis factor-alpha (TNF-α), and CC chemokine ligand 2, larger infarct size, greater cardiac dysfunction, and de novo cardiac hypertrophy [30]. In the experimental model of Wang W Ldlr−/− mice transplanted with Jak2-defi cient bone marrow cells showed accelerated atherosclerosis and larger plaques with enlarged necrotic nuclei [30]. Jak2-mutated macrophages on the one hand have Fig. 4. CHIP, atherosclerosis, dyslipidaemia and infl ammation [A. Stein, Basic Research in Cardiology, 2022] 19 Clonal hematopoiesis of unknown potential and cardiovascular disease... an impaired ability to engulf dead cells (defective efferocytosis). On the other hand, they show increased erythrophagocytosis (stimulates local oxidative stress) and lipid effl ux (prevents cholesterol leakage, so-called foam cells) [16, 31]. In contrast to TET2 and DNMT3A, where activation of the NLRP3 infl ammasome is the predominant proatherogenic mechanism, recent data show that ASXL1 and JAK2 CHIP facilitate activation of the absent in melanoma 2 (AIM2) infl ammasome [31]. The experimental data on the pathogenetic significance of CHIP for atherogenesis and CVD discussed above are schematically shown in Fig. 4. CHIP and cardiovascular disease – clinical evidence A review of literature, as well as convincing experimental evidence of a causal relationship, identifi es CHIP as a potent pathogenetic and risk factor for atherogenesis and CVD. Coronary artery disease. Myocardial infarction. Cardiogenic shock In a recent German study of 1142 patients, J. Brett Heimlich and colleagues presented the fi rst in literature trial assessing the correlation between CHIP and coronary artery disease (CAD) utilizing interventional coronary angiography. Correlation between CAD and CHIP was found in 18.4% of patients. A higher risk and more advanced left main disease hazard ratio (HR) 2.44 (95% Confi dence Interval – CI, 1.40-(4.27; p = 0.0018) and left anterior descending artery atherosclerosis HR 1.59 (1.12-2.24; p = 0.0092) was demonstrated in patients with CHIP, most commonly in TET2 mutation [32]. A signifi cant association between CHIP and CAD HR 1.36 (95% CI 1.07–1.73) (from 23-49) was established in a study by M. C. Honigberg et al. conducted through whole genome sequencing in a cohort of 19,606 women with premature menopause [33]. The correlation between ST-segment elevation myocardial infarction (STEMI) and CHIP was analyzed in 2 Chinese studies by S. Wang et al., and Xiaoxiao Zhao et al. Targeted deep sequencing for DNMT3A and TET2 mutations (VAF ≥ 2%) was used. According to S. Wang, the incidence of CHIP was 12.4%. During the 3-year follow-up period CHIP patients had elevated IL1β (p = 0.010) and IL-6 (p = 0.011) plasma levels, higher mortality (30.9% vs. 15.5%, p = 0.001) and more major adverse cardiovascular events (MACE) (44.5% vs. 21.8%, P < 0.001) [34]. Xiaoxiao Zhao et al. reported equivalent results in patients with type II diabetes and myocardial infarction (MI) with ST-segment elevation. Overall, 10.6% of patients had CHIP. In this population mortality rate was higher – HR 2.03 (95%, CI 1.073.84, p < 0.05) and increased further in patients with CHIP with TET2 mutation HR 5.24 (95% CI 2.02-13.61, p = 0.001). The study also speculated that the development of type 2 diabetes facilitates clonal haematopoiesis [35]. The risk of early MI in men < 40 years and women < 50 years is 4 times higher among individuals with CHIP, and so is the risk of abnormal aortic calcifi cation. The risk depends on the mutagenic load and the type of somatic mutation. CHIP with JAK2 mutation increases the likelihood of MI 12 times compared to CHIP with TET2 and DNMT3A gene mutations [12, 14]. In the CULPRIT-SHOCK study by M. Böhme et al. CHIP with TET2 and DNMT3A mutations was found in 29% of the 446 patients with MI and cardiogenic shock. CHIP patients were older, had elevated N-terminal prohormone of brain natriuretic peptide (NT-proBNP) and infl ammatory biomarkers, and had worse short-term outcomes and 30-day mortality (OR: 1.83; 95% CI: 1.05-3.21; p = 0.03) after adjustment for conventional risk factors [36]. In a Canadian study, Scolari FL et al analysed the association of CHIP, which was demonstrated in 22% of patients hospitalized with cardiogenic shock and with CHF, observed in outpatients in a 1:1 ratio. Patients with cardiogenic shock had a higher incidence of mutations (mainly TET2), higher levels of SCD40L, INF-γ, IL-4 and TNF-α and signifi cantly shorter survival at 30, 90 days and 3 years [37]. Heart failure and the left ventricle K. C. Kiefer et al. presented the fi rst study with deep-corrected targeted sequencing of 56 genes, with low VAF (0.5-2%) in 399 patients with chronic heart failure (CHF), followed for an average of 3.95 years. The authors found mutations in 87% of patients, most often in the genes DNMT3A, TET2, CBL, CCAAT/enhancer-binding protein alpha – CEBPA, EZH2, GNB1, PHF6, structural maintenance of chromosomes 1A – SMC1A, and SRSF2. The expanded risk mutation panel was associated with increased mortality compared to the average for the entire group. The authors minimized the infl uence of DNMT3A (165 patients) and TET2 (107 patients) by excluding them from the analysis. However, surprisingly, the remaining 7 mutations with low VAF were also associated with increased mortality (HR: 3.1; 95%, CI 1.8-5.4; p < 0.001) [5]. D. A. Pascual-Figal presented the fi rst evidence of accelerated clinical progression of HF in the absence of CAD in patients with CHIP [38]. Using deep sequencing with VAF ≥2% for 54 genes in 62 patients with HF and left ventricular ejection fraction (LVEF) <45% (age 74 ± 7 years, 74% men, 52% non-ischemic and LVEF 30 ± 8%, follow-up 3.5 years) the authors found the following: CHIP was established in 38.7% of patients; DNMT3A and TET2 mutations were associated with HF progression and higher mortality (HR: 2.79; 95% CI: 1.31 to 5.92; p = 0.008), more hospitalizations due to HF (HR: 3.84; 95% CI: 1.84 to 8.04; p < 0.001) and the composite of HF-related death or hospitalisation due to HF (HR: 4.41; 95% CI: 2.15 to 9.03; p < 0.001). G. Goranov, V. Goranova-Marinova 20 Arrhythmias A series of studies in recent years have established CHIP’s signifi cant proarrhythmic eff ect. In a population-based study, A. Schuermans et al. analysed the correlation between the prevalence of CHIP with diff erent mutagenic loads, subtypes of driver mutations and various incidental rhythm disorders such as supraventricular arrhythmias, bradyarrhythmias and ventricular arrhythmias (primary endpoint), cardiac arrest, atrial fi brillation and any arrhythmia (secondary endpoint) and myocardial interstitial fi brosis in 410,702 individuals [39]. In CHIP with VAF ≥ 2% and with VAF ≥ 10%, the adjusted hazard ratio for supraventricular arrhythmias was 1.11 (CI 1.041.18; p = 0.001) and 1.13 (CI 1.05-1.22; p = 0.001), respectively, for bradyarrhythmias – 1.09 (CI 1.01-1.19; p = 0.031) and 1.13 (CI 1.03-1.25; p = 0.011), for ventricular arrhythmias – 1.16 (CI, 1.00-1.34; p = 0.049) and 1.22 (CI 1.03-1.45; p = 0.021). CHIP with VAF ≥10% was associated with a risk of myocardial fi brosis with an odds ratio of 1.31 (CI 1.07–1.59; P = 0.009). The correlations were independent of CAD and HF, they were strongest in sinus arrest and were also proven in other non-driver gene mutations. According to the authors, CHIP is an independent risk factor for the occurrence of rhythm disorders. Ahn HJ et al studied the infl uence of CHIP on the progression of atrial fi brillation (AF) in an East Asian cohort [40]. They included 1004 patients and 3341 healthy controls with a CHIP prevalence of 23.6% in patients with AF versus 10.7% in the control group. Overall, in CHIP, the adjusted odds ratio for AF was 1.4, more common in long-standing AF odds ratio (OR) 1.50 (CI 95% 1.14-1.99, p = 0.004), followed by persistent – OR 1.44, and paroxysmal atrial fi brillation – OR 1.33. Additional analysis showed that patients with AF and CHIP were older, more often diabetic, with longer duration of arrhythmia, higher E/E’ and more dilated left atrium compared with those without CHIP (p < 0.05). Postoperative AF is a common complication in cardiac surgery. Ninni S and col. evaluated the prevalence and role of CHIP (576 genes with the HemePACT panel) in 104 patients with aortic stenosis undergoing aortic Table 1. Clinical Studies on CHIP and Cardiovascular Disease Study Population Key Findings Main CHIP Mutations Heimlich JB et al. 2024 1142 CAD patients (coronary angiography) CHIP in 18.4%; higher risk of left main CAD (HR 2.44) and LAD disease (HR 1.59) TET2 Honigberg MC et al. 2021 19,606 women with premature menopause CHIP associated with CAD (HR 1.36, CI 1.07–1.73) Multiple mutations Wang S et al. 2022 STEMI patients (n not specifi ed) CHIP prevalence 12.4%; higher IL-1β, IL-6, mortality (30.9% vs 15.5%) and MACE (44.5% vs 21.8%) DNMT3A, TET2 Zhao X et al. 2025 STEMI with type 2 diabetes (n not specifi ed) CHIP 10.6%; higher mortality HR 2.03, TET2 mutation HR 5.24 DNMT3A, TET2 Böhme M et al. 2022 (CULPRIT-SHOCK) 446 MI + cardiogenic shock CHIP prevalence 29%; higher NT-proBNP, biomarkers, 30-day mortality OR 1.83 TET2, DNMT3A Scolari FL et al. 2022 Cardiogenic shock and CHF CHIP 22%; higher infl ammatory markers, shorter survival at 30 d, 90d, 3y Mostly TET2 Kiefer KC et al. 2021 399 CHF patients CHIP in 87% (low VAF ≥0.5%); increased mortality HR 3.1 DNMT3A, TET2, others Pascual-Figal DA et al. 2021 62 HF patients (LVEF <45%) CHIP in 38.7%; associated with progression and mortality HR 2.79, hospitalization HR 3.84 DNMT3A, TET2 Dorsheimer L et al. 2019 Chronic ischemic HF CHIP worsens prognosis; mortality 37% vs 24%, HR 2.1 TET2, DNMT3A Schuermans A et al. 2023 410,702 population-based CHIP associated with arrhythmias: supraventricular HR 1.11–1.13, ventricular HR 1.16–1.22 Multiple mutations Ahn HJ et al. 2024 1004 AF patients vs 3341 controls CHIP prevalence 23.6% vs 10.7%; OR 1.4 for AF, strongest in long-standing AF Multiple mutations Ninni S et al. 2023 104 AS patients (AVR surgery) CHIP 29% (VAF ≥2%), 60% (VAF ≥1%); risk of postoperative AF OR 3.5 Multiple mutations Saadatagah S et al. 2024 UK Biobank + ARIC (≈200,000 participants) CHIP associated with AF; HR up to 1.45 depending on mutation subtype TET2, ASXL1 Lin AE et al. 2024 Mouse model TET2 knockout linked with AF via Ca++ handling defects, NLRP3 infl ammasome activation TET2 Raddatz MA et al. 2021 6866 patients CHIP 3.5% overall; associated with increased risk of severe aortic stenosis DNMT3A Mas-Peiro S et al. 2020 279 TAVI patients CHIP (DNMT3A, TET2) in >30%; higher mid-term mortality HR 4.81 DNMT3A, TET2 Mas-Peiro S et al. 2023 453 TAVR patients CHIP in >30%; higher long-term mortality HR 1.429 DNMT3A, TET2 Tan Y et al. 2025 425,211 UK Biobank participants CHIP increases AAA risk HR 1.21; higher in VAF ≥ 10% HR 1.35, ASXL1 HR 2.10 ASXL1 Soudet S et al. 2021 61 unprovoked PE patients CHIP in 20%, mainly DNMT3A; no eff ect on mortality at 2y with anticoagulation DNMT3A 21 Clonal hematopoiesis of unknown potential and cardiovascular disease... valve replacement surgery, and postoperative AF. In this relatively small group of patients, there was surprisingly an almost twofold diff erence in the prevalence of CHIP depending on VAF: in VAF ≥ 2% CHIP was 29%, while in VAF ≥ 1% CHIP was 60%. In patients with CHIP, the risk of postoperative AF was 3.5 times higher (OR: 3.5; 95%CI: 1.52-8.03; p = 0.003), along with higher levels of activated CD64 +, CD14 +, CD16 – circulating monocytes and macrophages in the myocardium [41]. There was also one interesting population-based, prospective study of 199,982 adults (4131 participants in the Atherosclerosis Risk in Communities (ARIC) study and 195,851 from the UK Biobank cohort) by Saadatagah et al. Its objective was to assess the relationships between CHIP, mutation subtypes, infl ammatory markers (high-sensitivity C-reactive protein – CRP; IL-6; IL-18), cardiac biomarkers (hsTnT and hs-TnI, NT-proBNP, echocardiographic indices), structural changes, and incidental AF [42]. In the ARIC group (mean age 76 years, follow-up 7.0 years) CHIP had a frequency of 24.7%, of which 11.6% had a VAF ≥ 10%. In the UKB cohort (mean age 56 years, follow-up 12.2 years) CHIP was 8.4%, of which 2.6% had a large VAF ≥ 10% [42]. The hazard ratios for AF were 1.12 (95% CI, 1.01-1.25; p = 0.04) with variations up to 1.45 depending on the mutagenic load and the individual somatic mutation subtypes [42]. The large TET2 CHIP had higher levels of IL-6, the large ASXL1 had higher levels of hs-TnT, increased left ventricular mass index, and both subtypes had an increased risk of AF [42]. In an attempt to fi nd a causal relationship between CHIP and rhythm disorders, Lin AE et al. studied calcium homeostasis with electrophysiological abnormalities as a potential proarrhythmic mechanism in cardiomyocytes in an experimental mouse model with TET2 knockout. Cardiomyocytes isolated from Ldlr–/– Tet2 knockout mice were found to have impaired calcium release from the sarcoplasmic reticulum into the cytosol, increased expression of the NLRP3 infl ammasome, and activation of Ca2+/calmodulin-dependent protein kinase II (CaMKII). According to the authors, these are likely contributing mechanisms for the occurrence of arrythmia in CHIP [43]. Aortic stenosis, TAVI, transcatheter aortic valve replacement, aortic aneurysm It is known that both CHIP and atherosclerotic aortic stenosis (AS) progress with age. In a general population study of 6866 patients above 40, M. A. Raddatz et al. found CHIP in 3.5% of participants, and incidental severe aortic stenosis – AS (Vmax and aortic valve area – AVA), was observed in 2.7% and 8.8% of them, respectively. CHIP (particularly with DNMT3A mutation) signifi cantly increases the risk of incidental AS [44]. Mas-Peiro et al. were the fi rst in literature to fi nd a signifi cant correlation between CHIP and medium-term (up to 8 months) and long-term outcomes (up to 4 years) in patients with degenerative atherosclerotic AS undergoing interventional implantations. The initial report analyzed 279 AS patients undergoing TAVI and later 453 patients undergoing transcatheter aortic valve replacement (TAVR), excluding all patients with intraoperative or early postoperative death. The results were similar – DNMT3Aor TET2-CHIP-driver mutations with VAF ≥ 2% were found in over 30% of patients, with an age-dependent increase from 25% (55-69 years) to 52.9% (90-100 years) and more common in women. CHIP patients showed increased medium-term (HR 4.81, 95% CI 1.49–15.57; p = 0.009) and long-term mortality (HR 1.429, 95%CI 1.014-2.013, p = 0.041) after successful intervention, more pronounced in non-smokers and older patients. DNMT3A mutation was associated with an increased ratio of pro-infl ammatory T-helper 17 (Th17) cells to anti-infl ammatory regulatory T-cells, and TET2 seemed to associate with increased levels of pro-infl ammatory monocytes characteristic of chronic infl ammatory diseases, as well as more frequent concomitant coronary and peripheral vascular disease [45, 46]. It is commonly believed that infl ammation is a major feature of aortic aneurysms (AA). A number of studies have demonstrated the presence of numerous infl ammatory cells, T-lymphocytes, macrophages, dendritic cells, neutrophils, B-cells, and mast cells, etc. in the walls of AA. AA are characterised by activation of infl ammasomes and increased secretion of cytokines – the same cellular components induced by mutations in the driver genes in CHIP [47]. In this sense, the results of a population study on the correlation between CHIP (VAF ≥ 2%) and genetic predisposition to abdominal aortic aneurysm (AAA) by Tan Y. et al. conducted on 425,211 individuals from the British Biobank [48] are not surprising. CHIP was associated with an increased risk of incidental AAA (HR 1.21, CI 95%, 1.01-1.44; p = 0.034), which was signifi cantly higher in CHIP VAF ≥ 10% (HR 1.35; CI 95%, 1.10-1.66; p = 0.0045) and more pronounced in ASXL1 mutation (HR, 2.10 CI 95%, 1.54-2.88; P < 0.001). On the other hand, the presence of 2 alleles IL6R p.Asp358Ala (genetic replacement of IL-6) reduced the risk of AAA in large CHIP clones (HR 0.48 CI, 95% 0.23-0.99; P = 0.046) [48]. Individuals without CHIP and those with a weak genetic predisposition had an insignifi cant risk of AAA (HR 2.15 95% CI, 1.632.85; p < 0.001) [48]. These results support the idea that a defi ciency in IL-6 signaling may serve as a therapeutic target for the prevention and treatment of AAA. Pulmonary embolism Unprovoked pulmonary embolism (UPE) is not associated with conventional risk factors, including thrombophilia, and accounts for about 50% of reported PE cases. In a small study of 61 patients with UPE,