Publications by authors named "Dirk-Soeren Luehmann"

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  • Metabolic-dysfunction associated steatohepatitis (MASH) is linked to conditions like obesity and diabetes, leading to liver problems and cardiovascular disease, but identifying it in patients can be difficult.* -
  • Researchers developed targeted peptide radiotracers for PET imaging to visualize changes in macrophage populations in the liver of mice with MASH, observing a decrease in resident macrophages and an increase in recruited ones during disease progression.* -
  • The study found a strong correlation between the PET imaging results and tissue analysis, suggesting that these radiotracers could be useful for non-invasive diagnostics and monitoring of MASH in humans.*
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  • Pulmonary fibrosis involves immune cell activity and fibroblast expansion, with CCR2+ monocytes playing a key role in its progression.
  • In mouse models, both an oral CCR2 inhibitor and the antifibrotic drug nintedanib reduced lung CCR2+ cells and fibrosis, indicating potential for using CCR2 inhibition as a treatment strategy.
  • CCR2-PET imaging could serve as a valuable tool for monitoring treatment responses and guiding patient management in pulmonary fibrosis.
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  • The study investigates the link between inflammation and tissue fibrosis in human cardiac diseases, revealing unique fibroblast populations that contribute to heart dysfunction.
  • Researchers used advanced techniques on heart samples to uncover these fibroblast types and their relationship with immune cells, specifically CCR2 macrophages, in promoting fibrosis through IL-1β signaling.
  • By blocking IL-1β signaling, the study demonstrated reduced fibrosis and improved heart function, suggesting that targeting inflammation could be a promising approach for treating cardiac fibrosis.
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  • Monocytes play a crucial role in atherosclerosis by turning into macrophages when they migrate to plaques, and this study explores how their glucose metabolism influences their behavior and contribution to the disease.
  • Researchers found that higher serum glucose levels are linked to increased monocyte numbers, while restricted diets hinder monocytes from switching energy sources, which reduces their presence in the blood.
  • The study highlights that glucose metabolism is vital for maintaining specific monocyte characteristics and functions, but inhibiting glucose uptake alone doesn't prevent atherosclerosis, likely because the remaining monocytes become more migratory.
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Background: Immune checkpoint inhibitor (ICI) usage has resulted in immune-related adverse events in patients with cancer, such as accelerated atherosclerosis. Of immune cells involved in atherosclerosis, the role of CCR2+ (CC motif chemokine receptor 2-positive) proinflammatory macrophages is well documented. However, there is no noninvasive approach to determine the changes of these cells in vivo following ICI treatment and explore the underlying mechanisms of immune-related adverse events.

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  • CCR2 is a receptor found on certain inflammatory monocytes and macrophages that play a role in heart failure, distinguishing them from other myeloid cells in the heart.
  • Researchers tested a specialized imaging probe (Cu-DOTA-ECL1i) that can identify these CCR2-expressing cells for potential use in imaging the human heart.
  • The probe showed increased uptake in patients who had suffered an acute myocardial infarction, primarily in the damaged area of the heart, and this was linked to poor heart muscle movement, suggesting it could help visualize inflammation in heart injuries.
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  • Tissue-resident macrophages play a complementary role to proinflammatory macrophages in driving atherosclerosis progression, making their detection and dynamic tracking crucial for understanding this disease.
  • The study aimed to create a targeted PET radiotracer, [Cu]Cu-ICT-01, to specifically image CD163-positive macrophages in mouse models of atherosclerosis and evaluate its potential as a biomarker in humans.
  • Results showed [Cu]Cu-ICT-01 had high binding affinity to CD163+ cells, demonstrated rapid clearance from blood and organs, and effectively detected CD163+ macrophages in various atherosclerosis models, confirming its specificity and functionality for tracking disease progression.
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Atherosclerosis is a chronic inflammatory disease and the leading cause of morbidity and mortality worldwide. CC motif chemokine ligand 2 and its corresponding cognate receptor 2 (CCL2/CCR2) signaling has been implicated in regulating monocyte recruitment and macrophage polarization during inflammatory responses that plays a pivotal role in atherosclerosis initiation and progression. In this study, we report the design and synthesis of a novel F radiolabeled small molecule radiotracer for CCR2-targeted positron emission tomography (PET) imaging in atherosclerosis.

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Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive and treatment-refractory malignancies. The lack of an effective screening tool results in the majority of patients being diagnosed at late stages, which underscores the urgent need to develop more sensitive and specific imaging modalities, particularly in detecting occult metastases, to aid clinical decision-making. The tumor microenvironment of PDAC is heavily infiltrated with myeloid-derived suppressor cells (MDSCs) that express C-C chemokine receptor type 2 (CCR2).

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Abdominal aortic aneurysms (AAAs) are prevalent with aging, and AAA rupture is associated with increased mortality. There is currently no effective medical therapy to prevent AAA rupture. The monocyte chemoattractant protein (MCP-1)/C-C chemokine receptor type 2 (CCR2) axis critically regulates AAA inflammation, matrix-metalloproteinase (MMP) production, and extracellular matrix (ECM) stability.

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The immune-fibrosis axis plays a critical role in cardiac remodeling after acute myocardial infarction. Imaging approaches to monitor temporal inflammation and fibroblast activation in mice have seen wide application in recent years. However, the repeatability of quantitative measurements remains challenging, particularly across multiple imaging centers.

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Sexual orientation, gender identity, and sex recorded at birth (SOGI) have been routinely excluded from demographic data collection tools, including in electronic medical record (EMR) systems. We assessed the ability of adding structured SOGI data capture to improve identification of transgender and nonbinary (TGNB) patients compared to using only International Classification of Diseases (ICD) codes and text mining and comment on the ethics of these cohort formation methods. We conducted a retrospective chart review to classify patient gender at a single institution using ICD-10 codes, structured SOGI data, and text mining for patients presenting for care between March 2019 and February 2021.

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Background: Rapidly dividing cells are more sensitive to radiation therapy (RT) than quiescent cells. In the failing myocardium, macrophages and fibroblasts mediate collateral tissue injury, leading to progressive myocardial remodeling, fibrosis, and pump failure. Because these cells divide more rapidly than cardiomyocytes, we hypothesized that macrophages and fibroblasts would be more susceptible to lower doses of radiation and that cardiac radiation could therefore attenuate myocardial remodeling.

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Abdominal aortic aneurysm (AAA) is a degenerative vascular disease impacting aging populations with a high mortality upon rupture. There are no effective medical therapies to prevent AAA expansion and rupture. We previously demonstrated the role of the monocyte chemoattractant protein-1 (MCP-1) / C-C chemokine receptor type 2 (CCR2) axis in rodent AAA pathogenesis via positron emission tomography/computed tomography (PET/CT) using CCR2 targeted radiotracer Cu-DOTA-ECL1i.

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Article Synopsis
  • Immune checkpoint inhibitors (ICIs), particularly in combination therapies, can cause severe side effects like myocarditis, characterized by infiltration of T lymphocytes and macrophages in the heart.
  • Research using a mouse model of ICI myocarditis revealed a significant increase in specific macrophage and T-cell populations, highlighting the inflammatory role of certain CCR2 monocyte-derived macrophages.
  • Interactions between T-cells and macrophages, influenced by signaling pathways such as IFN-γ and CXCR3, can exacerbate myocardial inflammation, and targeting these cells can reduce the severity of the condition.
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Abdominal aortic aneurysms (AAAs) are prevelant with aging, and AAA rupture is associated with high mortality. There is currently no effective medical therapy for AAA rupture. Previous work demonstrated that the monocyte chemoattractant protein (MCP-1) / C-C chemokine receptor type 2 (CCR2) axis critically regulates AAA inflammation, matrix-metalloproteinase (MMP) production, and extracellular matrix (ECM) stability.

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Background: Immune checkpoint inhibitors (ICIs), antibodies targeting PD-1/PD-L1 or CTLA4 have revolutionized cancer management but are associated with devastating immune-related adverse events (irAEs) including myocarditis. The main risk factor for ICI myocarditis is the use of combination PD-1 and CTLA4 inhibition. ICI-myocarditis is often fulminant and is pathologically characterized by myocardial infiltration of T lymphocytes and macrophages.

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To expand the single-dose duration over which noninvasive clinical and preclinical cancer imaging can be conducted with high sensitivity, and well-defined spatial and temporal resolutions, a facile strategy to prepare ultrasmall nanoparticulate X-ray contrast media (nano-XRCM) as dual-modality imaging agents for positron emission tomography (PET) and computed tomography (CT) has been established. Synthesized from controlled copolymerization of triiodobenzoyl ethyl acrylate and oligo(ethylene oxide) acrylate monomers, the amphiphilic statistical iodocopolymers (ICPs) could directly dissolve in water to afford thermodynamically stable solutions with high aqueous iodine concentrations (>140 mg iodine/mL water) and comparable viscosities to conventional small molecule XRCM. The formation of ultrasmall iodinated nanoparticles with hydrodynamic diameters of 10 nm in water was confirmed by dynamic and static light scattering techniques.

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Background: Matrix metalloproteinases (MMPs) play a key role in the pathogenesis of abdominal aortic aneurysm (AAA). Imaging aortic MMP activity, especially using positron emission tomography to access high sensitivity, quantitative data, could potentially improve AAA risk stratification. Here, we describe the design, synthesis, characterization, and evaluation in murine AAA and human aortic tissue of a first-in-class MMP-targeted positron emission tomography radioligand, Cu-RYM2.

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CD36 mediates the uptake of long-chain fatty acids (FAs), a major energy substrate for the myocardium. Under excessive FA supply, CD36 can cause cardiac lipid accumulation and inflammation while its deletion reduces heart FA uptake and lipid content and increases glucose utilization. As a result, CD36 was proposed as a therapeutic target for obesity-associated heart disease.

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Glioblastoma multiforme (GBM) is the most prevalent and aggressive primary malignant brain cancer in adults, and it carries a poor prognosis. Despite the current multimodality treatment, including surgery, radiation, and chemotherapy, the overall survival is still poor. Neurooncological imaging plays an important role in the initial diagnosis and prediction of the treatment response of GBM.

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Background: Adherence to screening guidelines among transgender and non-binary (TGNB) populations is not well studied. This study examines breast cancer screening patterns among TGNB patients at an urban academic medical center.

Methods: Demographic information, risk factors, and screening mammography were collected.

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Monocytes are part of the mononuclear phagocytic system. Monocytes play a central role during inflammatory conditions and a better understanding of their dynamics might open therapeutic opportunities. In the present study, we focused on the characterization and impact of monocytes on brown adipose tissue (BAT) functions during tissue remodeling.

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Diffuse intrinsic pontine glioma (DIPG) is an invasive pediatric brainstem malignancy exclusively in children without effective treatment due to the often-intact blood-brain tumor barrier (BBTB), an impediment to the delivery of therapeutics. Herein, we used focused ultrasound (FUS) to transiently open BBTB and delivered radiolabeled nanoclusters (Cu-CuNCs) to tumors for positron emission tomography (PET) imaging and quantification in a mouse DIPG model. First, we optimized FUS acoustic pressure to open the blood-brain barrier (BBB) for effective delivery of Cu-CuNCs to pons in wildtype mice.

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Cardiac macrophages represent a heterogeneous cell population with distinct origins, dynamics, and functions. Recent studies have revealed that C-C Chemokine Receptor 2 positive (CCR2) macrophages derived from infiltrating monocytes regulate myocardial inflammation and heart failure pathogenesis. Comparatively little is known about the functions of tissue resident (CCR2) macrophages.

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