A multi-center study to predict the risk of intraoperative hypothermia in gynecological surgery patients using preoperative variables.

OBJECTIVES: Hypothermia is highly common in patients undergoing gynecological surgeries under general anesthesia, so the length of hospitalization and even the risk of mortality are substantially increased. Our aim was to develop a simple and practical model to preoperatively identify gynecological surgery patients at risk of intraoperative hypothermia. METHODS: In this retrospective study, we collected data from 802 patients who underwent gynecological surgery at three medical centers from June 2022 to August 2023. We further allocated the patients to a training group, an internal validation group, or an external validation group. The preliminary predictive factors for intraoperative hypothermia in gynecological patients were determined using the least absolute shrinkage and selection operator (LASSO) method. The final predictive factors were subsequently identified through multivariate logistic regression analysis, and a nomogram for predicting the occurrence of hypothermia was established. RESULTS: A total of 802 patients were included, with 314 patients in the training cohort (mean age 48.5 ± 12.6 years), 130 patients in the internal validation cohort (mean age 49.9 ± 12.5 years), and 358 patients in the external validation cohort (mean age 47.6 ± 14.0 years). LASSO regression and multivariate logistic regression analyses indicated that body mass index, minimally invasive surgery, baseline heart rate, baseline body temperature, history of previous surgery, and aspartate aminotransferase level were associated with intraoperative hypothermia in gynecological surgery patients. This nomogram was constructed based on these six variables, with a C-index of 0.712 for the training cohort. CONCLUSIONS: We established a practical predictive model that can be used to preoperatively predict the occurrence of hypothermia in gynecological surgery patients. CLINICAL TRIAL REGISTRATION: chictr.org.cn, identifier ChiCTR2300071859.

cGMP-dependent kinase 2, Na+/H+ exchanger NHE3, and PDZ-adaptor NHERF2 co-assemble in apical membrane microdomains.

AIM: Trafficking, membrane retention, and signal-specific regulation of the Na+/H+ exchanger 3 (NHE3) are modulated by the Na+/H+ Exchanger Regulatory Factor (NHERF) family of PDZ-adapter proteins. This study explored the assembly of NHE3 and NHERF2 with the cGMP-dependent kinase II (cGKII) within detergent-resistant membrane microdomains (DRMs, "lipid rafts") during in vivo guanylate cycle C receptor (Gucy2c) activation in murine small intestine. METHODS: Small intestinal brush border membranes (siBBMs) were isolated from wild type, NHE3-deficient, cGMP-kinase II-deficient, and NHERF2-deficient mice, after oral application of the heat-stable Escherichia coli toxin (STa) analog linaclotide. Lipid raft and non-raft fractions were separated by Optiprep density gradient centrifugation of Triton X-solubilized siBBMs. Confocal microscopy was performed to study NHE3 redistribution after linaclotide application in vivo. RESULTS: In the WT siBBM, NHE3, NHERF2, and cGKII were strongly raft associated. The raft association of NHE3, but not of cGKII, was NHERF2 dependent. After linaclotide application to WT mice, lipid raft association of NHE3 decreased, that of cGKII increased, while that of NHERF2 did not change. NHE3 expression in the BBM shifted from a microvillar to a terminal web region. The linaclotide-induced decrease in NHE3 raft association and in microvillar abundance was abolished in cGKII-deficient mice, and strongly reduced in NHERF2-deficient mice. CONCLUSION: NHE3, cGKII, and NHERF2 form a lipid raft-associated signal complex in the siBBM, which mediates the inhibition of salt and water absorption by Gucy2c activation. NHERF2 enhances the raft association of NHE3, which is essential for its close interaction with the exclusively raft-associated activated cGKII.

Identification and Expression Analysis of UPS Gene Family in Potato.

Ureide permeases (UPSs) mediate the transport of ureides, including allantoin and allantoate, which act as nitrogen-transporting compounds in plants and have recently been found to play a role in cellular signaling. To date, UPSs have not been reported in potato, and their identification is important for further function studies and for understanding molecular mechanisms of plant adverse responses. Based on potato genomic data, we identified 10 StUPS genes in potato (Solanum tuberosum L.). Then, we conducted a comprehensive study of the identified StUPS genes using bioinformatics methods. Genome phylogenetic and genomic localization analyses revealed that StUPSs can be classified into four categories, are highly homologous to Arabidopsis thaliana UPS members, and are distributed on three chromosomes. The six StUPS genes were investigated by RT-qPCR, and the findings indicated that all of these genes are involved in the response to several stresses, including low nitrogen, cold, ABA, salt, H2O2, and drought. This study establishes a strong theoretical framework for investigating the function of potato UPS genes, as well as the molecular mechanisms underlying the responses of these genes to various environmental stresses.

Association of serum 25-hydroxyvitamin D3 levels with carotid artery intima-media thickness and carotid atherosclerotic plaques in smokers.

OBJECTIVE: This study explores the association of serum 25-hydroxyvitamin D3 (25(OH)D3) levels with carotid artery intima-media thickness (CIMT), and the presence of carotid atherosclerotic plaques in individuals with a history of smoking. METHODS: A total of 469 patients suspected of having carotid atherosclerosis, aged 52 to 73 years with an average age of 65.26 ±â€¯4.37 years, were recruited from the author's hospital from January 2023 to October 2023. All patients had a smoking history of nearly 5 years. Based on their serum 25(OH)D3 levels, they were divided into two groups: the normal group (serum level 30-50 ng/mL, n = 300) and the deficiency group (<30 ng/mL, n = 169). General details of the two patient groups were collected. Carotid artery ultrasound was employed to assess pulse wave velocity (PWV), carotid artery compliance coefficient (CC), and CIMT. Blood chemistry analysis measured serum lipid metabolism indicators including total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HD-LC). The relationship between CIMT and each variable was analyzed through Pearson correlation, and logistic regression was used to identify risk factors influencing carotid artery plaque development. RESULTS: General patient information between the two groups showed no significant differences (P > 0.05). Patients in the 25(OH)D3 deficiency group exhibited elevated left and right PWV and CC compared to the 25(OH)D3 normal group (P < 0.05). The deficiency group exhibited larger CIMT and plaque area compared to the normal group (P < 0.05). Additionally, the deficiency group demonstrated higher levels of TC, LDL-C, and HD-LC compared to the normal group (P < 0.05). A moderate positive correlation was found between TC, LDL-C, and CIMT (P < 0.05), while a strong positive correlation existed between 25(OH)D3 and CIMT (P < 0.05). In smokers, the formation of carotid artery plaque was associated with factors such as patient age, CIMT, serum LDL-C, and 25(OH)D3 levels (P < 0.05). As age, CIMT, LDL-C levels increased, and 25(OH)D3 levels decreased, the risk of carotid plaques in smokers increased (P < 0.05). CONCLUSIONS: Smokers with lower 25(OH)D3 levels exhibit higher CIMT and more prominent carotid atherosclerotic plaques, indicating increased arterial stiffness and elevated cardiovascular risk. These findings demonstrate crucial implications that insufficient levels of vitamin D may potentially contribute to a higher risk of atherosclerosis among smokers.

In-situ-sprayed therapeutic hydrogel for oxygen-actuated Janus regulation of postsurgical tumor recurrence/metastasis and wound healing.

Surgery is the mainstay of treatment modality for malignant melanoma. However, the deteriorative hypoxic microenvironment after surgery is recognized as a stemming cause for tumor recurrence/metastasis and delayed wound healing. Here we design and construct a sprayable therapeutic hydrogel (HIL@Z/P/H) encapsulating tumor-targeted nanodrug and photosynthetic cyanobacteria (PCC 7942) to prevent tumor recurrence/metastasis while promote wound healing. In a postsurgical B16F10 melanoma model in female mice, the nanodrug can disrupt cellular redox homeostasis via the photodynamic therapy-induced cascade reactions within tumor cells. Besides, the photosynthetically generated O2 by PCC 7942 can not only potentiate the oxidative stress-triggered cell death to prevent local recurrence of residual tumor cells, but also block the signaling pathway of hypoxia-inducible factor 1α to inhibit their distant metastasis. Furthermore, the long-lasting O2 supply and PCC 7942-secreted extracellular vesicles can jointly promote angiogenesis and accelerate the wound healing process. Taken together, the developed HIL@Z/P/H capable of preventing tumor recurrence/metastasis while promoting wound healing shows great application potential for postsurgical cancer therapy.

Simultaneous Circular Dichroism and Wavefront Manipulation with Generalized Pancharatnam-Berry Phase Metasurfaces.

Simultaneous circular dichroism and wavefront manipulation have gained considerable attention in various applications, such as chiroptical spectroscopy, chiral imaging, sorting and detection of enantiomers, and quantum optics, which can improve the miniaturization and integration of the optical system. Typically, structures with n-fold rotational symmetry (n ≥ 3) are used to improve circular dichroism, as they induce stronger interactions between the electric and magnetic fields. However, manipulating the wavefront with these structures remains challenging because they are commonly considered isotropic and lack a geometric phase response in linear optics. Here, we propose and experimentally demonstrate an approach to achieve simultaneous circular dichroism (with a maximum value of ∼0.62) and wavefront manipulation using a plasmonic metasurface made up of C3 Archimedes spiral nanostructures. The circular dichroism arises from the magnetic dipole-dipole resonance and strong interactions between adjacent meta-atoms. As a proof of concept, two metadevices are fabricated and characterized in the near-infrared regime. This configuration possesses the potential for future applications in photodetection, chiroptical spectroscopy, and the customization of linear and nonlinear optical responses.

Toward Quantitative Multisite Preclinical Imaging Studies in Acute Myocardial Infarction: Evaluation of the Immune-Fibrosis Axis.

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. We aimed to determine reproducibility of quantitative inflammation and fibroblast activation images acquired at 2 facilities after myocardial infarction in mice. Methods: Mice underwent coronary artery ligation and sequential imaging with 68Ga-DOTA-ECL1i to assess chemokine receptor type 2 expression at 3 d after myocardial infarction and 68Ga-FAPI-46 to assess fibroblast activation protein expression at 7 d after myocardial infarction. Images were acquired at 1 center using either a local or a consensus protocol developed with the second center; the protocols differed in the duration of isoflurane anesthesia and the injected tracer dose. A second group of animals were scanned at the second site using the consensus protocol. Image analyses performed by each site and just by 1 site were also compared. Results: The uptake of 68Ga-DOTA-ECL1i in the infarct territory tended to be higher when the consensus protocol was used (P = 0.03). No difference was observed between protocol acquisitions for 68Ga-FAPI-46. Compared with the local protocol, the consensus protocol decreased variability between individual animals. When a matched consensus protocol was used, the 68Ga-DOTA-ECL1i infarct territory percentage injected dose per gram of tissue was higher on images acquired at site B than on those acquired at site A (P = 0.006). When normalized to body weight as SUV, this difference was mitigated. Both the percentage injected dose per gram of tissue and the SUV were comparable between sites for 68Ga-FAPI-46. Image analyses at the sites differed significantly, but this difference was mitigated when all images were analyzed at site A. Conclusion: The application of a standardized acquisition protocol may lower variability within datasets and facilitate comparison of molecular radiotracer distribution between preclinical imaging centers. Like clinical studies, multicenter preclinical studies should use centralized core-based image analysis to maximize reproducibility across sites.

Sequence Note: Characterization of Two HIV-1 Strains with Novel Unique Recombinant Genome in Hebei, China.

In China, the proportion of HIV-1 infections due to men who have sex with men (MSM) has increased rapidly. More and more new subtypes are found among the MSM population besides known CRF01_AE, CRF07_BC, and B. The co-circulation of several HIV subtypes in the same population provides the opportunity to develop a new circulating recombinant form (CRF) and unique recombinant form (URF). Here we reported two new URFs from two HIV-1 positive subjects infected through homosexual contact in Hebei, China. Phylogenetic and recombinant analyses based on the near full-length genome (NFLG) of the two URFs are the second-generation recombinant strains that originated from B, CRF01_AE, and CRF07_BC. The CRF01_AE segments in the genome of two URFs originated from cluster 4 of CRF01_AE strains, while the CRF07_BC segments were clustered with 07BC_N in the phylogenetic tree. The emergence of the novel CRF01_AE/CRF07_BC and CRF01_AE/B recombinant forms indicated the importance of the continuous monitoring of the HIV-1 epidemic and new URFs among the MSM population.

Function and inhibition of P38 MAP kinase signaling: Targeting multiple inflammation diseases.

Inflammation is a natural host defense mechanism that protects the body from pathogenic microorganisms. A growing body of research suggests that inflammation is a key factor in triggering other diseases (lung injury, rheumatoid arthritis, etc.). However, there is no consensus on the complex mechanism of inflammatory response, which may include enzyme activation, mediator release, and tissue repair. In recent years, p38 MAPK, a member of the MAPKs family, has attracted much attention as a central target for the treatment of inflammatory diseases. However, many p38 MAPK inhibitors attempting to obtain marketing approval have failed at the clinical trial stage due to selectivity and/or toxicity issues. In this paper, we discuss the mechanism of p38 MAPK in regulating inflammatory response and its key role in major inflammatory diseases and summarize the synthetic or natural products targeting p38 MAPK to improve the inflammatory response in the last five years, which will provide ideas for the development of novel clinical anti-inflammatory drugs based on p38 MAPK inhibitors.

Glutaminolysis is a Potential Therapeutic Target for Kidney Diseases.

Metabolic reprogramming contributes to the progression and prognosis of various kidney diseases. Glutamine is the most abundant free amino acid in the body and participates in more metabolic processes than other amino acids. Altered glutamine metabolism is a prominent feature in different kidney diseases. Glutaminolysis converts glutamine into the TCA cycle metabolite, alpha-ketoglutarate, via a cascade of enzymatic reactions. This metabolic pathway plays pivotal roles in inflammation, maladaptive repair, cell survival and proliferation, redox homeostasis, and immune regulation. Given the crucial role of glutaminolysis in bioenergetics and anaplerotic fluxes in kidney pathogenesis, studies on this cascade could provide a better understanding of kidney diseases, thus inspiring the development of potential methods for targeted therapy. Emerging evidence has shown that targeting glutaminolysis is a promising therapeutic strategy for ameliorating kidney disease. In this narrative review, equation including keywords related to glutamine, glutaminolysis and kidney are subjected to an exhaustive search on Pubmed database, we identified all relevant articles published before 1 April, 2024. Afterwards, we summarize the regulation of glutaminolysis in major kidney diseases and its underlying molecular mechanisms. Furthermore, we highlight therapeutic strategies targeting glutaminolysis and their potential clinical applications.

Comprehensive characterization of ERV-K (HML-8) in the chimpanzee genome revealed less genomic activity than humans.

Endogenous retroviruses (ERVs) originate from ancestral germline infections caused by exogenous retroviruses. Throughout evolution, they have become fixed within the genome of the animals into which they were integrated. As ERV elements coevolve with the host, they are normally epigenetically silenced and can become upregulated in a series of physiological and pathological processes. Generally, a detailed ERV profile in the host genome is critical for understanding the evolutionary history and functional performance of the host genome. We previously characterized and cataloged all the ERV-K subtype HML-8 loci in the human genome; however, this has not been done for the chimpanzee, the nearest living relative of humans. In this study, we aimed to catalog and characterize the integration of HML-8 in the chimpanzee genome and compare it with the integration of HML-8 in the human genome. We analyzed the integration of HML-8 and found that HML-8 pervasively invaded the chimpanzee genome. A total of 76 proviral elements were characterized on 23/24 chromosomes, including detailed elements distribution, structure, phylogeny, integration time, and their potential to regulate adjacent genes. The incomplete structure of HML-8 proviral LTRs will undoubtedly affect their activity. Moreover, the results indicated that HML-8 integration occurred before the divergence between humans and chimpanzees. Furthermore, chimpanzees include more HML-8 proviral elements (76 vs. 40) and fewer solo long terminal repeats (LTR) (0 vs. 5) than humans. These results suggested that chimpanzee genome activity is less than the human genome and that humans may have a better ability to shape and screen integrated proviral elements. Our work is informative in both an evolutionary and a functional context for ERVs.

Near Full-Length Genome Characterization of Two Novel Unique Recombinants (CRF01_AE/CRF07_BC) in Beijing, China.

With the prevalence of human immunodeficiency virus type 1 (HIV-1) CRF01_AE and CRF07_BC subtypes in China, the co-circulation of multiple subtypes in the HIV-1-positive population may result in dual infection or superinfection in the population, leading to the emergence of unique recombinant forms (URFs) of the HIV-1 virus. In this study, two second-generation unique recombinant strains, BI0114 and BI0116, were identified, and their near full-length genome sequences were obtained. Recombination analysis showed that both sequences were isoforms of URF_0107, and they were second-generation unique recombinant strains formed by the recombination of CRF01_AE and CRF07_BC, with the isoforms being CRF01_AE and CRF0107_BC, respectively. The continued emergence of novel CRF01_AE/CRF07_BC recombinant strains suggests that the epidemiological, preventive, and control situation of HIV-1 is complex and that the relevant health authorities urgently need to establish responses to the challenges posed by changes in the pattern of strain recombination.

A unified classification system for HIV-1 5' long terminal repeats.

The HIV-1 provirus mainly consists of internal coding region flanked by 1 long terminal repeats (LTRs) at each terminus. The LTRs play important roles in HIV-1 reverse transcription, integration, and transcription. However, despite of the significant study advances of the internal coding regions of HIV-1 by using definite reference classification, there are no systematic and phylogenetic classifications for HIV-1 5' LTRs, which hinders our elaboration on 5' LTR and a better understanding of the viral origin, spread and therapy. Here, by analyzing all available resources of 5' LTR sequences in public databases following 4 recognized principles for the reference classification, 83 representatives and 14 consensus sequences were identified as representatives of 2 groups, 6 subtypes, 6 sub-subtypes, and 9 CRFs. To test the reliability of the supplemented classification system, the constructed references were applied to identify the 5' LTR assignment of the 22 clinical isolates in China. The results revealed that 16 out of 22 tested strains showed a consistent subtype classification with the previous LTR-independent classification system. However, 6 strains, for which recombination events within 5' LTR were demonstrated, unexpectedly showed a different subtype classification, leading a significant change of binding sites for important transcription factors including SP1, p53, and NF-κB. The binding change of these transcriptional factors would probably affect the transcriptional activity of 5' LTR. This study supplemented a unified classification system for HIV-1 5' LTRs, which will facilitate HIV-1 characterization and be helpful for both basic and clinical research fields.

Efficacy and safety of azvudine in symptomatic adult COVID-19 participants who are at increased risk of progressing to critical illness: a study protocol for a multicentre randomized double-blind placebo-controlled phase III trial.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 will coexist with humans for a long time, and it is therefore important to develop effective treatments for coronavirus disease 2019 (COVID-19). Recent studies have demonstrated that antiviral therapy is a key factor in preventing patients from progressing to severe disease, even death. Effective and affordable antiviral medications are essential for disease treatment and are urgently needed. Azvudine, a nucleoside analogue, is a potential low-cost candidate with few drug interactions. However, validation of high-quality clinical studies is still limited. METHODS: This is a multicentre, randomized, double-blind, placebo-controlled phase III clinical trial involving 1096 adult patients with mild-to-moderate symptoms of COVID-19 who are at high risk for progression to severe COVID-19. Patients will be randomized to (1) receive azvudine tablets 5 mg daily for a maximum of 7 days or (2) receive placebo five tablets daily. All participants will be permitted to use a standard treatment strategy except antiviral therapy beyond the investigational medications. The primary outcome will be the ratio of COVID-19-related critical illness and all-cause mortality among the two groups within 28 days. DISCUSSION: The purpose of this clinical trial is to determine whether azvudine can prevent patients at risk of severe disease from progressing to critical illness and death, and the results will identify whether azvudine is an effective and affordable antiviral treatment option for COVID-19. TRIAL REGISTRATION: ClinicalTrials.gov NCT05689034. Registered on 18 January 2023.

Comprehensive Identification and Characterization of HML-9 Group in Chimpanzee Genome.

Endogenous retroviruses (ERVs) are related to long terminal repeat (LTR) retrotransposons, comprising gene sequences of exogenous retroviruses integrated into the host genome and inherited according to Mendelian law. They are considered to have contributed greatly to the evolution of host genome structure and function. We previously characterized HERV-K HML-9 in the human genome. However, the biological function of this type of element in the genome of the chimpanzee, which is the closest living relative of humans, largely remains elusive. Therefore, the current study aims to characterize HML-9 in the chimpanzee genome and to compare the results with those in the human genome. Firstly, we report the distribution and genetic structural characterization of the 26 proviral elements and 38 solo LTR elements of HML-9 in the chimpanzee genome. The results showed that the distribution of these elements displayed a non-random integration pattern, and only six elements maintained a relatively complete structure. Then, we analyze their phylogeny and reveal that the identified elements all cluster together with HML-9 references and with those identified in the human genome. The HML-9 integration time was estimated based on the 2-LTR approach, and the results showed that HML-9 elements were integrated into the chimpanzee genome between 14 and 36 million years ago and into the human genome between 18 and 49 mya. In addition, conserved motifs, cis-regulatory regions, and enriched PBS sequence features in the chimpanzee genome were predicted based on bioinformatics. The results show that pathways significantly enriched for ERV LTR-regulated genes found in the chimpanzee genome are closely associated with disease development, including neurological and neurodevelopmental psychiatric disorders. In summary, the identification, characterization, and genomics of HML-9 presented here not only contribute to our understanding of the role of ERVs in primate evolution but also to our understanding of their biofunctional significance.

Development of a [89Zr]Zr-labeled Human Antibody using a Novel Phage-displayed Human scFv Library.

PURPOSE: Tax-interacting protein 1 (TIP1) is a cancer-specific radiation-inducible cell surface antigen that plays a role in cancer progression and resistance to therapy. This study aimed to develop a novel anti-TIP1 human antibody for noninvasive PET imaging in patients with cancer. EXPERIMENTAL DESIGN: A phage-displayed single-chain variable fragment (scFv) library was created from healthy donors' blood. High-affinity anti-TIP1 scFvs were selected from the library and engineered to human IgG1. Purified Abs were characterized by size exclusion chromatography high-performance liquid chromatography (SEC-HPLC), native mass spectrometry (native MS), ELISA, BIAcore, and flow cytometry. The labeling of positron emitter [89Zr]Zr to the lead Ab, L111, was optimized using deferoxamine (DFO) chelator. The stability of [89Zr]Zr-DFO-L111 was assessed in human serum. Small animal PET studies were performed in lung cancer tumor models (A549 and H460). RESULTS: We obtained 95% pure L111 by SEC-HPLC. Native MS confirmed the intact mass and glycosylation pattern of L111. Conjugation of three molar equivalents of DFO led to the optimal DFO-to-L111 ratio of 1.05. Radiochemical purity of 99.9% and specific activity of 0.37 MBq/µg was obtained for [89Zr]Zr-DFO-L111. [89Zr]Zr-DFO-L111 was stable in human serum over 7 days. The immunoreactive fraction in cell surface binding studies was 96%. In PET, preinjection with 4 mg/kg cold L111 before [89Zr]Zr-DFO-L111 (7.4 MBq; 20 µg) significantly (P < 0.01) enhanced the tumor-to-muscle standard uptake values (SUVmax) ratios on day 5 compared with day 2 postinjection. CONCLUSIONS: L111 Ab targets lung cancer cells in vitro and in vivo. [89Zr]Zr-DFO-L111 is a human antibody that will be evaluated in the first in-human study of safety and PET imaging.

Ketosis prevents abdominal aortic aneurysm rupture through C-C chemokine receptor type 2 downregulation and enhanced extracellular matrix balance.

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. We therefore hypothesized that a diet intervention that can modulate CCR2 axis may therapeutically impact AAA risk of rupture. Since ketone bodies (KBs) can trigger repair mechanisms in response to inflammation, we evaluated whether systemic ketosis in vivo could reduce CCR2 and AAA progression. Male Sprague-Dawley rats underwent surgical AAA formation using porcine pancreatic elastase and received daily ß-aminopropionitrile to promote AAA rupture. Rats with AAAs received either a standard diet, ketogenic diet (KD), or exogenous KBs (EKB). Rats receiving KD and EKB reached a state of ketosis and had significant reduction in AAA expansion and incidence of rupture. Ketosis also led to significantly reduced aortic CCR2 content, improved MMP balance, and reduced ECM degradation. Consistent with these findings, we also observed that Ccr2-/- mice have significantly reduced AAA expansion and rupture. In summary, this study demonstrates that CCR2 is essential for AAA expansion, and that its modulation with ketosis can reduce AAA pathology. This provides an impetus for future clinical studies that will evaluate the impact of ketosis on human AAA disease.

Development of a CCR2 targeted 18F-labeled radiotracer for atherosclerosis imaging with PET.

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 18F radiolabeled small molecule radiotracer for CCR2-targeted positron emission tomography (PET) imaging in atherosclerosis. The binding affinity of this radiotracer to CCR2 was evaluated via in vitro binding assay using CCR2+ membrane and cells. Ex vivo biodistribution was carried out in wild type mice to assess radiotracer pharmacokinetics. CCR2 targeted PET imaging of plaques was performed in two murine atherosclerotic models. The sensitive detection of atherosclerotic lesions highlighted the potential of this radiotracer for CCR2 targeted PET and warranted further optimization.

Chemokine Receptor 2 Targeted PET/CT Imaging Distant Metastases in Pancreatic Ductal Adenocarcinoma.

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). These CCR2-expressing MDSCs accumulate at a very early stage of metastasis and greatly outnumber PDAC cells, making CCR2 a promising target for detecting early, small metastatic lesions that have scant PDAC cells. Herein, we evaluated a CCR2 targeting PET tracer (68Ga-DOTA-ECL1i) for PET imaging on PDAC metastasis in two mouse models. Positron emission tomography/computed tomography (PET/CT) imaging of 68Ga-DOTA-ECL1i was performed in a hemisplenic injection metastasis model (KI) and a genetically engineered orthotopic PDAC model (KPC), which were compared with 18F-FDG PET concurrently. Autoradiography, hematoxylin and eosin (H&E), and CCR2 immunohistochemical staining were performed to characterize the metastatic lesions. PET/CT images visualized the PDAC metastases in the liver/lung of KI mice and in the liver of KPC mice. Quantitative uptake analysis revealed increased metastasis uptake during disease progression in both models. In comparison, 18F-FDG PET failed to detect any metastases during the time course studies. H&E staining showed metastases in the liver and lung of KI mice, within which immunostaining clearly demonstrated the overexpression of CCR2 as well as CCR2+ cell infiltration into the normal liver. H&E staining, CCR2 staining, and autoradiography also confirmed the expression of CCR2 and the uptake of 68Ga-DOTA-ECL1i in the metastatic foci in KPC mice. Using our novel CCR2 targeted radiotracer 68Ga-DOTA-ECL1i and PET/CT, we demonstrated the sensitive and specific detection of CCR2 in the early PDAC metastases in two mouse models, indicating its potential in future clinical translation.

Development of a CD163-Targeted PET Radiotracer That Images Resident Macrophages in Atherosclerosis.

Tissue-resident macrophages are complementary to proinflammatory macrophages to promote the progression of atherosclerosis. The noninvasive detection of their presence and dynamic variation will be important to the understanding of their role in the pathogenesis of atherosclerosis. The goal of this study was to develop a targeted PET radiotracer for imaging CD163-positive (CD163+) macrophages in multiple mouse atherosclerosis models and assess the potential of CD163 as a biomarker for atherosclerosis in humans. Methods: CD163-binding peptide was identified using phage display and conjugated with a NODAGA chelator for 64Cu radiolabeling ([64Cu]Cu-ICT-01). CD163-overexpressing U87 cells were used to measure the binding affinity of [64Cu]Cu-ICT-01. Biodistribution studies were performed on wild-type C57BL/6 mice at multiple time points after tail vein injection. The sensitivity and specificity of [64Cu]Cu-ICT-01 in imaging CD163+ macrophages upregulated on the surface of atherosclerotic plaques were assessed in multiple mouse atherosclerosis models. Immunostaining, flow cytometry, and single-cell RNA sequencing were performed to characterize the expression of CD163 on tissue-resident macrophages. Human carotid atherosclerotic plaques were used to measure the expression of CD163+ resident macrophages and test the binding specificity of [64Cu]Cu-ICT-01. Results: [64Cu]Cu-ICT-01 showed high binding affinity to U87 cells. The biodistribution study showed rapid blood and renal clearance with low retention in all major organs at 1, 2, and 4 h after injection. In an ApoE-/- mouse model, [64Cu]Cu-ICT-01 demonstrated sensitive and specific detection of CD163+ macrophages and capability for tracking the progression of atherosclerotic lesions; these findings were further confirmed in Ldlr-/- and PCSK9 mouse models. Immunostaining showed elevated expression of CD163+ macrophages across the plaques. Flow cytometry and single-cell RNA sequencing confirmed the specific expression of CD163 on tissue-resident macrophages. Human tissue characterization demonstrated high expression of CD163+ macrophages on atherosclerotic lesions, and ex vivo autoradiography revealed specific binding of [64Cu]Cu-ICT-01 to human CD163. Conclusion: This work reported the development of a PET radiotracer binding CD163+ macrophages. The elevated expression of CD163+ resident macrophages on human plaques indicated the potential of CD163 as a biomarker for vulnerable plaques. The sensitivity and specificity of [64Cu]Cu-ICT-01 in imaging CD163+ macrophages warrant further investigation in translational settings.