[Aberrant mitochondrial dynamics in myeloid neoplasms].

Age-related clonal hematopoiesis and myeloid malignancies arise from hematopoietic stem cells and progenitors with genetic abnormalities. Advances in next-generation sequencing technology have led to the identification of a wide variety of genetic alterations involved in disease onset. However, it remains unclear how diverse genetic alterations, lacking disease specificity, lead to the development of myeloid malignancies and the progression of clonal hematopoiesis. Mitochondrial abnormalities and their roles in various pathological conditions such as aging, inflammation, neurological diseases, cardiac diseases, and cancer have recently been revealed, and have garnered attention as new therapeutic targets. This review focuses on regulation of mitochondrial dynamics and outlines the role of mitochondria in myeloid malignancies and clonal hematopoiesis.

Detection and interpretation of clonal hematopoiesis variants during routine solid tumor next-generation sequencing: a single institution experience.

Clonal hematopoiesis (CH) and Clonal Cytopenia of Undetermined Significance (CCUS) are recently recognized diagnostic entities that serve as an independent risk factor for cardiovascular disease and myeloid malignancy. CH is an incidental finding and evaluation of the incidence of CH/CCUS associated mutations in solid tumor Next Generation Sequencing (NGS) samples was undertaken to better understand the prevalence of mutations in this population. A retrospective review of clinical sequencing data for solid tumor malignancies diagnosed February 2022-April 2023 on NGS data was performed. Cases were reviewed for variants in genes associated with CH/CCUS. Variant allele frequencies and other factors of the sequencing data were assessed for determining risk of CH/CCUS. 2,479 cases were evaluated during the study period. Of these, 29 cases demonstrated potential CH/CCUS associated mutations with a total of 33 variants identified. These were identified in a variety of tumor types, with gliomas being the most common. Significant cardiac histories were found in over half of cases identified and few cases had abnormal blood counts. Detailed criteria for flagging variants as suspicious for CH and recommend these criteria as future guidelines for reporting are described. These variants are incidental findings which require more extensive follow up or change in therapy management utilizing a single institutional cohort.

Clonal hematopoiesis with DNMT3A mutations is associated with multiple system atrophy.

BACKGROUND: Clonal hematopoiesis of indeterminate potential (CHIP) is associated with cardiovascular diseases and other disorders, possibly via inflammation. Recent research suggests a connection of CHIP with neurodegenerative disorders. OBJECTIVE: We aimed to investigate the association between multiple system atrophy (MSA) and CHIP. METHODS: We included 100 patients with MSA and 4457 controls. Targeted sequencing of peripheral blood DNA samples was performed, focusing on a panel of 25 genes commonly. LINKED TO CHIP: The prevalence of CHIP in patients with MSA was assessed against controls at variant allele frequency (VAF) thresholds of 1.5 % and 2.0 %. RESULTS: DNMT3A mutation rates were significantly higher in patients with MSA, with a VAF of 1.5 %, which remained significant after adjusting for age and sex (adjusted odds ratio, 1.848; 95 % CI, 1.024-3.335; p = 0.0416). CONCLUSION: Our results suggest an association between DNMT3A mutations and MSA.

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.

The Role of Inflammation in the Pathogenesis of Cardiogenic Shock Secondary to Acute Myocardial Infarction: A Narrative Review.

Cardiogenic shock (CS) is one of the most serious complications of myocardial infarction (MI) with a high mortality rate. The timely and effective prevention and early suppression of this adverse event may influence the prognosis and outcome in patients with MI complicated by CS (MI CS). Despite the use of existing pharmaco-invasive options for maintaining an optimal pumping function of the heart in patients with MI CS, its mortality remains high, prompting the search for new approaches to pathogenetic therapy. This review considers the role of the systemic inflammatory response in the pathogenesis of MI CS. The primary processes involved in its initiation are described, including the progression from the onset of MI to the generalization of the inflammatory response and the development of multiple organ dysfunction. The approaches to anti-inflammatory therapy in patients with CS are discussed, and further promising research directions are outlined. In this review, we updated and summarized information on the inflammatory component of MI CS pathogenesis with a particular focus on its foundational aspects. This will facilitate the identification of specific inflammatory phenotypes and endotypes in MI CS and the development of targeted therapeutic strategies for this MI complication.

Dynamically adjusted cell fate decisions and resilience to mutant invasion during steady-state hematopoiesis revealed by an experimentally parameterized mathematical model.

A major next step in hematopoietic stem cell (HSC) biology is to enhance our quantitative understanding of cellular and evolutionary dynamics involved in undisturbed hematopoiesis. Mathematical models have been and continue to be key in this respect, and are most powerful when parameterized experimentally and containing sufficient biological complexity. In this paper, we use data from label propagation experiments in mice to parameterize a mathematical model of hematopoiesis that includes homeostatic control mechanisms as well as clonal evolution. We find that nonlinear feedback control can drastically change the interpretation of kinetic estimates at homeostasis. This suggests that short-term HSC and multipotent progenitors can dynamically adjust to sustain themselves temporarily in the absence of long-term HSCs, even if they differentiate more often than they self-renew in undisturbed homeostasis. Additionally, the presence of feedback control in the model renders the system resilient against mutant invasion. Invasion barriers, however, can be overcome by a combination of age-related changes in stem cell differentiation and evolutionary niche construction dynamics based on a mutant-associated inflammatory environment. This helps us understand the evolution of e.g., TET2 or DNMT3A mutants, and how to potentially reduce mutant burden.

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)-1ß 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.

Ultralow-dose irradiation enables engraftment and intravital tracking of disease initiating niches in clonal hematopoiesis.

Recent advances in imaging suggested that spatial organization of hematopoietic cells in their bone marrow microenvironment (niche) regulates cell expansion, governing progression, and leukemic transformation of hematological clonal disorders. However, our ability to interrogate the niche in pre-malignant conditions has been limited, as standard murine models of these diseases rely largely on transplantation of the mutant clones into conditioned mice where the marrow microenvironment is compromised. Here, we leveraged live-animal microscopy and ultralow dose whole body or focal irradiation to capture single cells and early expansion of benign/pre-malignant clones in the functionally preserved microenvironment. 0.5 Gy whole body irradiation (WBI) allowed steady engraftment of cells beyond 30 weeks compared to non-conditioned controls. In-vivo tracking and functional analyses of the microenvironment showed no change in vessel integrity, cell viability, and HSC-supportive functions of the stromal cells, suggesting minimal inflammation after the radiation insult. The approach enabled in vivo imaging of Tet2+/- and its healthy counterpart, showing preferential localization within a shared microenvironment while forming discrete micro-niches. Notably, stationary association with the niche only occurred in a subset of cells and would not be identified without live imaging. This strategy may be broadly applied to study clonal disorders in a spatial context.

Epstein-Barr virus-positive, primary cutaneous marginal zone lymphoma, with transformation: Case report and review of the literature.

Epstein-Barr Virus (EBV) positive primary cutaneous marginal zone lymphoma (PCMZL) is uncommon and subsequent transformation is rare. METHODS: We report a patient with EBV positive PCMZL with subsequent transformation to plasmablastic lymphoma and review the literature for transformed PCMZL to assess clinical and pathologic characteristics. In the case we describe, the patient presented with multifocal PCMZL, developed large B cell transformation with plasmacytic differentiation, followed by plasmablastic transformation (PBL), and ultimately died of disease progression despite multiple lines of therapy. Past history was significant for psoriatic arthritis (multiple prior lines of immunomodulatory therapy). The lymphomas and non-involved bone marrow share the same somatic DNMT3A and TET2 mutations, suggesting clonal relatedness and an association with clonal hematopoiesis (CH). RESULTS: Eighteen cases complied the cohort (seventeen cases from the literature and the case reported herein). Nearly half of the eighteen cases of PCMZL with transformation died of progressive disease (44%). Transformed cases were more commonly seen in patients with >2 sites at initial diagnosis. EBV was assessed in 5 patients, 3 were positive (all died of disease). Two patients with NGS studies demonstrated TET2 and DNMT3A mutations. CONCLUSIONS: Transformation of EBV positive PCMZL appears to be a poor prognostic indicator, with our reported case being the first well defined case transformed to PBL, suspected to arise from myeloid-CH.

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

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

Natural history of chronic idiopathic neutropenia of the adult.

Chronic idiopathic neutropenia (CIN) is a rare benign condition  caused by an immune attack against neutrophils, either primary or in the context of other autoimmune conditions, lymphoproliferative syndromes, and inborn errors of immunity. In this single-center prospective study, 131 adult CIN patients were enrolled (median age 55 years, range: 20-93). At baseline, 56% had anti-neutrophil autoantibodies and 31% had autoimmune comorbidities. Over a median 3-year follow-up, the rate of grade ≥ 2 infections was 42%, with 10% grade ≥ 3, irrespective of neutrophil counts, demographics, and anti-neutrophil antibodies positivity, and G-CSF was used in 6 patients only. No malignant evolution nor deaths were observed. Bone marrow evaluation showed a large granular lymphocyte (LGL) infiltrate in 52%, mostly polyclonal, and hypocellularity in 31% of cases. Immune-histochemistry highlighted deposits of IgG, IgM, and complement fractions C3 and C4d in most cases. Interestingly, 19% of tested patients displayed somatic mutations of myeloid genes with an association with age. In conclusion, adult CIN appears to be a benign condition without life-threatening infections, yet deserving an extensive hematologic evaluation including bone marrow assessment to inform the differential diagnosis.

Decoding Clonal Hematopoiesis: Emerging Themes and Novel Mechanistic Insights.

Clonal hematopoiesis (CH), the relative expansion of mutant clones, is derived from hematopoietic stem cells (HSCs) with acquired somatic or cytogenetic alterations that improve cellular fitness. Individuals with CH have a higher risk for hematological and non-hematological diseases, such as cardiovascular disease, and have an overall higher mortality rate. Originally thought to be restricted to a small fraction of elderly people, recent advances in single-cell sequencing and bioinformatics have revealed that CH with multiple expanded mutant clones is universal in the elderly population. Just a few years ago, phylogenetic reconstruction across the human lifespan and novel sensitive sequencing techniques showed that CH can start earlier in life, decades before it was thought possible. These studies also suggest that environmental factors acting through aberrant inflammation might be a common theme promoting clonal expansion and disease progression. However, numerous aspects of this phenomenon remain to be elucidated and the precise mechanisms, context-specific drivers, and pathways of clonal expansion remain to be established. Here, we review our current understanding of the cellular mechanisms driving CH and specifically focus on how pro-inflammatory factors affect normal and mutant HSC fates to promote clonal selection.

Regulators of clonal hematopoiesis and physiological consequences of this condition.

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

[Infection stress and a driver mutation interact to promote transformation to hematological malignancies].

Myelodysplastic syndrome (MDS) is a refractory cancer that arises from hematopoietic stem cells and predominantly affects elderly adults. In addition to driver gene mutations, which are also found in clonal hematopoiesis in healthy elderly people, systemic inflammation caused by infection or collagen disease has long been known as an extracellular factor in the pathogenesis of MDS. Wild-type HSCs have an "innate immune memory" that functions in response to infection and inflammatory stress, and my colleagues and I used an infection stress model to demonstrate that the innate immune response by the TLR-TRIF-PLK-ELF1 pathway is similarly critical in impairment of hematopoiesis and dysregulation of chromatin in MDS stem cells. This revealed that not only are MDS stem cells expanded by the TRAF6-NF-kB pathway, the innate immune response is also involved in generating MDS stem cells. In this review, I will present research findings related to "innate immune memory," one of the pathogenic mechanisms of blood cancer, and discuss future directions for basic pathological research and potential therapeutic development.

[Aging and clonal hematopoesis.]

The number of somatic mutations among all tissues increases along with age. This process was well-studied in hematopoietic stem cells (HSCs). Some mutations lead to a proliferative advantage and expansion of HSCs to form a dominant clone. Clonal hematopoiesis is general in the elderly population. Clonal hematopoiesis of indeterminate potential (CHIP) is a more common phenomenon in the elderly and is defined as somatic mutations in clonal blood cells without any other hematological malignancies. The development of CHIP is an independent risk factor for hematological malignancies, cardiovascular diseases, and reduced overall survival. CHIP is frequently associated with mutations in DNMT3A and TET2 genes involved in DNA methylation. The epigenetic human body clocks have been developed based on the age-related changes in methylation, making it possible to detect epigenetic aging. The combination of epigenetic aging and CHUP is associated with adverse health outcomes. Further research will reveal the significance of clonal hematopoiesis and CHIP in aging, acquiring various diseases, and determining the feasibility of influencing the mutagenic potential of clones.

Rising Prevalence of Low-Frequency PPM1D Gene Mutations after Second HDCT in Multiple Myeloma.

Multiple myeloma (MM) first-line treatment algorithms include immuno-chemotherapy (ICT) induction, high-dose chemotherapy (HDCT) and autologous stem cell transplant (ASCT) consolidation, followed by lenalidomide maintenance. After these initial therapies, most patients suffer a disease relapse and require subsequent treatment lines including ICT, additional HDCT and ASCT, or novel immunotherapies. The presence of somatic mutations in peripheral blood cells has been associated with adverse outcomes in a variety of hematological malignancies. Nonsense and frameshift mutations in the PPM1D gene, a frequent driver alteration in clonal hematopoiesis (CH), lead to the gain-of-function of Wip1 phosphatase, which may impair the p53-dependent G1 checkpoint and promote cell proliferation. Here, we determined the presence of PPM1D gene mutations in peripheral blood cells of 75 subsequent myeloma patients in remission after first or second HDCT/ASCT. The prevalence of truncating PPM1D gene mutations emerged at 1.3% after first HDCT/ASCT, and 7.3% after second HDCT/ASCT, with variant allele frequencies (VAF) of 0.01 to 0.05. Clinical outcomes were inferior in the PPM1D-mutated (PPM1Dmut) subset with median progression-free survival (PFS) of 15 vs. 37 months (p = 0.0002) and median overall survival (OS) of 36 vs. 156 months (p = 0.001) for the PPM1Dmut and PPM1Dwt population, respectively. Our data suggest that the occurrence of PPM1D gene mutations in peripheral blood cells correlates with inferior outcomes after ASCT in patients with multiple myeloma.

[Prognostic Value of DTA Mutations in Patients with Newly Diagnosed Acute Myeloid Leukemia].

OBJECTIVE: To investigate the prognostic significance of DTA (DNMT3A, TET2, ASXL1 ) gene mutations in patients with non-M3 acute myeloid leukemia (AML). METHODS: The clinical data of 180 newly diagnosed AML patients hospitalized in the First People's Hospital of Changzhou from January 2018 to April 2022 were retrospectively analyzed. Next-generation sequencing technology was used to detect 150 gene mutations in the patients, and log-rank tests and Cox regression models were used to analyze the prognostic factors. RESULTS: DTA gene mutations were detected in 83 (46.1%) of 180 AML patients. Compared to patients without DTA mutations, patients with DTA mutations were significantly older (P < 0.001). The median overall survival (OS) time and disease-free survival (DFS) time in the DTA mutation group were significantly shorter than those in the group without DTA mutation (both P < 0.05). Multivariate analysis showed that age ≥ 60 years (P < 0.001), with DTA mutation (P =0.018), and intermediate-risk (relative to favorable-risk) (P =0.005) were independent risk factors for OS in AML patients. CONCLUSION: AML patients with DTA mutations are relatively older, with shorter median OS time and DFS time, and poor prognosis.

Clonal hematopoiesis of indeterminate potential is associated with reduced risk of cognitive impairment in patients with chronic kidney disease.

INTRODUCTION: Clonal hematopoiesis of indeterminate potential (CHIP) and dementia disproportionately burden patients with chronic kidney disease (CKD). The association between CHIP and cognitive impairment in CKD patients is unknown. METHODS: We conducted time-to-event analyses in up to 1452 older adults with CKD from the Chronic Renal Insufficiency Cohort who underwent CHIP gene sequencing. Cognition was assessed using four validated tests in up to 6 years mean follow-up time. Incident cognitive impairment was defined as a test score one standard deviation below the baseline mean. RESULTS: Compared to non-carriers, CHIP carriers were markedly less likely to experience impairment in attention (adjusted hazard ratio [HR] [95% confidence interval {CI}] = 0.44 [0.26, 0.76], p = 0.003) and executive function (adjusted HR [95% CI] = 0.60 [0.37, 0.97], p = 0.04). There were no significant associations between CHIP and impairment in global cognition or verbal memory. DISCUSSION: CHIP was associated with lower risks of impairment in attention and executive function among CKD patients. HIGHLIGHTS: Our study is the first to examine the role of CHIP in cognitive decline in CKD. CHIP markedly decreased the risk of impairment in attention and executive function. CHIP was not associated with impairment in global cognition or verbal memory.