PET Imaging of Sphingosine-1-Phosphate Receptor 1 with [18F]TZ4877 in Nonhuman Primates.

Purpose: The sphingosine-1-phosphate receptor-1 (S1PR1) is involved in regulating responses to neuroimmune stimuli. There is a need for S1PR1-specific radioligands with clinically suitable brain pharmcokinetic properties to complement existing radiotracers. This work evaluated a promising S1PR1 radiotracer, [18F]TZ4877, in nonhuman primates. Procedures: [18F]TZ4877 was produced via nucleophilic substitution of tosylate precursor with K[18F]/F- followed by deprotection. Brain PET imaging data were acquired with a Focus220 scanner in two Macaca mulatta (6, 13 years old) for 120-180 min following bolus injection of 118-163 MBq [18F]TZ4877, with arterial blood sampling and metabolite analysis to measure the parent input function and plasma free fraction (f P). Each animal was scanned at baseline, 15-18 min after 0.047-0.063 mg/kg of the S1PR1 inhibitor ponesimod, 33 min after 0.4-0.8 mg/kg of the S1PR1-specific compound TZ82112, and 167-195 min after 1 ng/kg of the immune stimulus endotoxin. Kinetic analysis with metabolite-corrected input function was performed to estimate the free fraction corrected total distribution volume (V T/f P). Whole-body dosimetry scans were acquired in 2 animals (1M, 1F) with a Biograph Vision PET/CT System, and absorbed radiation dose estimates were calculated with OLINDA. Results: [18F]TZ4877 exhibited fast kinetics that were described by the reversible 2-tissue compartment model. Baseline [18F]TZ4877 f P was low (< 1%), and [18F]TZ4877 V T/f P values were 233-866 mL/cm3. TZ82112 dose-dependently reduced [18F]TZ4877 V T/f P, while ponesimod and endotoxin exhibited negligible effects on V T/f P, possibly due to scan timing relative to dosing. Dosimetry studies identified the critical organs of gallbladder (0.42 (M) and 0.31 (F) mSv/MBq) for anesthetized nonhuman primate. Conclusions: [18F]TZ4877 exhibits reversible kinetic properties, but the low f P value limits quantification with this radiotracer. S1PR1 is a compelling PET imaging target, and these data support pursuing alternative F-18 labeled radiotracers for potential future human studies.

Composite diffuse large B-cell lymphoma and peripheral T-cell lymphoma: a case report with two-year follow-up and literature review.

Composite lymphoma is an uncommon type of lymphoid malignancy, and those consisting of concurrent diffuse large B-cell lymphoma (DLBCL) and peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS) in the same organ are rare. Here, we report a case of a 75-year-old male patient admitted to our emergency department with intestinal obstruction presenting with abdominal pain and vomiting. He underwent partial resection of the small intestine under general anesthesia, and subsequent histopathology confirmed the mass to be composite DLBCL and PTCL-NOS. The patient received chemotherapy with a rituximab-based regimen and achieved complete remission (CR). However, the recurrent disease presented with obstruction again ten months after treatment. He refused a second surgery, but salvage treatment was not effective. The patient survived for 20 months after diagnosis. In addition, we did a literature review to understand the clinical features, pathology, treatment, and prognosis of this type of composite lymphoma.

Bortezomib-based chemotherapy for patients with Waldenström macroglobulinemia: a single-center experience.

Waldenström Macroglobulinemia (WM) is a rare type of non-Hodgkin lymphoma with no standard first-line treatment, and the disease is still incurable. This study evaluated the clinical efficacy, safety, and prognostic factors of bortezomib-based chemotherapy as initial treatment in WM patients. We retrospectively analyzed the clinical data collected from 44 newly diagnosed WM patients treated with bortezomib-based regimens at the Affiliated Hospital of Nantong University from December 2011 to June 2021. Univariate and multivariate analyses were used to assess prognostic factors for overall survival (OS) and progression-free survival (PFS). The median age was 67 years old, with an overall response rate (ORR) of 93.2%, complete response (CR) rate of 6.8%, and very good partial response (VGPR) rate of 29.5%. With a median follow-up of 39 months, the 2-year overall survival (OS) and 2-year PFS rates were 88.0% and 59.0%, respectively. By the last follow-up, eight patients (18.2%) had died. Univariate analysis showed patients with B symptoms, elevated LDH, international prognostic stage system of WM (IPSSWM) stage III, high Revised IPSSWM (R-IPSSWM) score, and those who did not achieve VGPR were associated with shorter PFS. And patients with B symptoms, with high R-IPSSWM score, and who do not achieve VGPR also had shorter OS than their counterparts. Multivariate analysis confirmed that failure to achieve VGPR was an independent adverse prognostic factor for OS and PFS. In conclusion, we showed that bortezomib-based chemotherapy effectively treated newly diagnosed patients with WM. However, combinations of drugs with different mechanisms are recommended for patients with a high tumor burden. In addition, deep remission can improve patients' survival.

CtBP proteins transactivate matrix metalloproteinases and proinflammatory cytokines to mediate the pathogenesis of abdominal aortic aneurysm.

Abdominal aortic aneurysm (AAA) is a life-threatening disorder that occurs in the aorta. The inflammatory thickness of the aneurysm wall and perianeurysmal fibrosis are two main causes of AAA pathogenesis; however, the molecular mechanisms involved in these two processes are still unclear. We discovered that C-terminal binding protein 1 (CtBP1) and CtBP2 were overexpressed in the aortas of AAA-model mice created by treatment with CaCl2 and elastase. Molecular analyses revealed that the CtBP heterodimer couples with histone acetyltransferase p300 and transcription factor AP1 (activator protein 1) to transactivate a set of matrix metalloproteinases (MMPs, including MMP1a, 3, 7, 9, and 12) and proinflammatory cytokines, including interleukin-1 ß (IL-1ß), IL-6, and tumor necrosis factor-alpha (TNF-α). Knockdown of CtBPs or AP1 subunits or blockage of CtBPs with specific small molecule inhibitors significantly suppressed the in vitro expression of MMPs and proinflammatory cytokines. The administration of CtBP inhibitors in AAA-model mice also inhibited MMPs and proinflammatory cytokines, thereby improving the AAA outcome. Taken together, our results revealed a new regulatory mechanism involving MMPs and proinflammatory cytokines in the pathogenesis of AAA. This discovery suggests that targeting CtBPs may be a therapeutic strategy for AAA by attenuating the inflammatory response and matrix destruction.

Efficient delivery of the Bcl-2 antisense oligonucleotide G3139 via nucleus-targeted aCD33-NKSN nanoparticles.

G3139 is an antisense oligodeoxyribonucleotide (ODN) developed as a Bcl-2 down-regulating agent for the treatment of acute myelogenous leukemia (AML). However, the clinical efficacy of G3139 has been shown to be limited due to its rapid plasma clearance and low permeability. To enhance the effective delivery of G3139, this work prepared a novel nano gene delivery vector (aCD33-NKSN) consisting of a CD33 antigbody (aCD33), a nuclear localization signal (NLS), gene fusion peptides (KALA), and stearic acid (SA) for CD33 antigen targeting and nuclear localization. The aCD33-NKSN/G3139 nanoparticles were spherical and uniformly sized with a positive charge and sustained release. They had an excellent G3139 loading capacity and colloidal stability. The aCD33-NKSN/G3139 delivered G3139 into the nucleus of Kasumi-1 cells and aCD33-NKSN/G3139 could more effectively inhibited Bcl-2 expression and induced apoptosis in Kasumi-1 cells versus free G3139. The aCD33-NKSN/G3139 administration was more effective at inhibiting tumor growth, and significantly prolonged the survival time of mice in contrast to free G3139. The results illustrate that aCD33-NKSN/G3139 nanoparticles could improve the antitumor activity of encapsulated G3139 due to aCD33 targeting and the ability to perform nuclear localization, The results offer a promising clinical application potential for the treatment of acute myeloid leukemia.

Radiosynthesis and characterization of a carbon-11 PET tracer for receptor-interacting protein kinase 1.

INTRODUCTION: Receptor-interacting protein kinase 1 (RIPK1) has emerged as a crucial regulator of necroptosis and the inflammatory response by activating a group of downstream immune receptors. It has been recognized as a pivotal contributor to cell death and inflammation in various physiological and pathological processes. RIPK1 deficiency or dysregulation in humans can cause severe immunodeficiency and neurodegenerative diseases such as multiple sclerosis and amyotrophic lateral sclerosis. Recently, diverse structures of RIPK1 inhibitors have been developed as potential therapeutics for neurodegenerative diseases and other pathological inflammatory processes. 7-oxo-2,4,5,7-tetrahydro-6H-pyrazolo[3,4-c]pyridine (Compound 5 or TZ7774) was reported as a novel RIPK1 inhibitor with a Ki of 0.91 nM that can suppress necroptosis in mouse and human cells. To develop a radiotracer for investigating the RIPK1 in vivo, we radiosynthesized [11C]TZ7774 and performed preliminary in vitro and in vivo evaluations in rodents and macaque. METHODS: Synthesis of the desmethyl precursor TZ7790 was performed and optimized. The radiosynthesis of [11C]TZ7774 was achieved through TZ7790 reacting with [11C]methyl iodide via N-methylation. Ex vivo biodistribution of [11C]TZ7774 was performed in normal Sprague-Dawley rats. Characterization of [11C]TZ7774 in response to inflammation was performed using ex vivo biodistribution study in normal and LPS treated (10 mg/kg) C57BL/6 mice, and in vitro autoradiography and immunohistochemistry of the spleen. MicroPET brain study of [11C]TZ7774 in the macaque was also performed. RESULTS AND CONCLUSIONS: The radiosynthesis of [11C]TZ7774 was achieved with good radiochemical yield (30-40%, decay corrected to the end of bombardment (EOB)), high chemical purity (>90%), high radiochemical purity (>99%), and high molar activity (>207 GBq/µmol, decay corrected to EOB). Biodistribution studies in Sprague-Dawley rats showed [11C]TZ7774 has a high brain uptake of 0.53 (%ID/g) at 5 min post injection; pancreas, spleen, kidney, and liver also showed a relatively high initial uptake of 0.49, 0.41, 0.62, and 0.95 at 5 min respectively. Uptake of [11C]TZ7774 increased in LPS-treated C57BL/6 mice by 40.9%, 90.4%, and 54.9% in liver, spleen, and kidney respectively. In vitro autoradiography study also revealed increased uptake of [11C]TZ7774 in the spleen of LPS-treated mice. Further characterization with immunohistochemistry confirmed increased expression of RIPK1 in red and white pulp of the spleen for mice pre-treated with LPS. MicroPET demonstrated that [11C]TZ7774 had good initial brain uptake in macaque with an (SUV) of ∼3.7 at 6-10 min, and quickly washed out from brain. These data confirm successful radiosynthesis of a RIPK1 specific radiotracer [11C]TZ7774. Our preliminary studies showed good response to LPS-induced inflammation in rodents and good uptake in macaque brain. [11C]TZ7774 has a potential to image RIPK1 related necroptosis and inflammatory processes.

Radiosynthesis and evaluation of a fluorine-18 radiotracer [18F]FS1P1 for imaging sphingosine-1-phosphate receptor 1.

Assessment of sphingosine-1-phosphate receptor 1 (S1PR1) expression could be a unique tool to determine the neuroinflammatory status for central nervous system (CNS) disorders. Our preclinical results indicate that PET imaging with [11C]CS1P1 radiotracer can quantitatively measure S1PR1 expression changes in different animal models of inflammatory diseases. Here we developed a multiple step F-18 labeling strategy to synthesize the radiotracer [18F]FS1P1, sharing the same structure with [11C]CS1P1. We explored a wide range of reaction conditions for the nucleophilic radiofluorination starting with the key ortho-nitrobenzaldehyde precursor 10. The tertiary amine additive TMEDA proved crucial to achieve high radiochemical yield of ortho-[18F]fluorobenzaldehyde [18F]12 starting with a small amount of precursor. Based on [18F]12, a further four-step modification was applied in one-pot to generate the target radiotracer [18F]FS1P1 with 30-50% radiochemical yield, >95% chemical and radiochemical purity, and a high molar activity (37-166.5 GBq µmol-1, decay corrected to end of synthesis, EOS). Subsequently, tissue distribution of [18F]FS1P1 in rats showed a high brain uptake (ID% g-1) of 0.48 ± 0.06 at 5 min, and bone uptake of 0.27 ± 0.03, 0.11 ± 0.02 at 5, and 120 min respectively, suggesting no in vivo defluorination. MicroPET studies showed [18F]FS1P1 has high macaque brain uptake with a standard uptake value (SUV) of ∼2.3 at 120 min. Radiometabolite analysis of macaque plasma samples indicated that [18F]FS1P1 has good metabolic stability, and no major radiometabolite confounded PET measurements of S1PR1 in nonhuman primate brain. Overall, [18F]FS1P1 is a promising F-18 S1PR1 radiotracer worthy of further clinical investigation for human use.

PET Study of Sphingosine-1-phosphate Receptor 1 Expression in Response to S. aureus Infection.

Sphingosine-1-phosphate receptor 1 (S1PR1) plays a crucial role in infectious diseases. Targeting S1PR1 provides protection against pathogens, such as influenza viruses. This study is aimed at investigating S1PR1 in response to bacterial infection by assessing S1PR1 expression in S. aureus-infected mice. A rodent local muscle bacterial infection model was developed by injecting S. aureus to the lower hind limb of Balb/c mice. The changes of S1PR1 expression in response to bacterial infection and blocking treatment were assessed using ex vivo biodistribution and in vivo positron emission tomography (PET) after intravenous injection of an S1PR1-specific radiotracer [18F]TZ4877. The specificity of [18F]TZ4877 was assessed using S1PR1-specific antagonist, NIBR-0213, and S1PR1-specific DsiRNA pretreated the animals. Immunohistochemical studies were performed to confirm the increase of S1PR1 expression in response to infection. Ex vivo biodistribution data showed that the uptake of [18F]TZ4877 was increased 30.6%, 54.3%, 74.3%, and 115.3% in the liver, kidney, pancreas, and thymus of the infected mice, respectively, compared to that in normal control mice, indicating that S1PR1 is involved in the early immune response to bacterial infection. NIBR-0213 or S1PR1-specific DsiRNA pretreatment reduced the tissue uptake of [18F]TZ4877, suggesting that uptake of [18F]TZ4877 is specific. Our PET/CT study data also confirmed that infected mice have increased [18F]TZ4877 uptake in several organs comparing to that in normal control mice. Particularly, compared to control mice, a 39% increase of [18F]TZ4877 uptake was observed in the infected muscle of S. aureus mice, indicating that S1PR1 expression was directly involved in the inflammatory response to infection. Overall, our study suggested that S1PR1 plays an important role in the early immune response to bacterial infection. The uptake of [18F]TZ4877 is tightly correlated with the S1R1 expression in response to S. aureus infection. PET with S1PR1-specific radiotracer [18F]TZ4877 could provide a noninvasive tool for detecting the early S1PR1 immune response to infectious diseases.

Effects of Modified Simultaneous Unipolar Saline-Irrigated Radiofrequency Ablation in Patients with Atrial Fibrillation Combined with Mitral Valve Disease.

OBJECTIVE: To investigate the therapeutic effects of a modified simultaneous unipolar saline-irrigated radiofrequency ablation by intracardiac operation under direct vision in patients with mitral valve diseases combined with atrial fibrillation (AF). METHODS: A total of 168 patients with mitral valve diseases combined with AF who underwent unipolar saline-irrigated radiofrequency ablation modified maze procedures were enrolled and divided into the mitral stenosis (MS) group (n = 87) and the mitral insufficiency (MI) group (n = 81). RESULTS: Those with a left atrium diameter (LAD) < 55 mm had a better cardioversion effect during the mid-term post-operation than those with a LAD ≥ 55 mm (P < 0.05). The cardioversion effect during the mid-term post-operation was better in those with a duration of AF < 2 years than those with AF ≥ 2 years (P < 0.05). The LAD reduced significantly during the early postoperative period in the MS group (P < 0.05). Compared with the early postoperative period, LAD further reduced, and the EF increased significantly during the mid-term post-operation (P<0.05). The LAD reduced significantly during the early postoperative period in the MI group (P < 0.05), together with relatively decreased EF (P < 0.05). Compared with the early postoperative period, LAD further reduced, and the EF increased significantly during the mid-term post-operation (P<0.05). The improvement of LAD in the MI group during the mid-term post-operation was better than that in the MS group (P < 0.05). CONCLUSION: The cardioversion effects and the improvement in cardiac function during the mid-term post-operation were good in the radiofrequency ablation by intracardiac operation under direct vision in patients with different mitral valve diseases combined with AF. The cardioversion effects during the early postoperative period and the mid-term post-operation were better in patients with MI than in those with MS.

Pinocembrin inhibited cardiomyocyte pyroptosis against doxorubicin-induced cardiac dysfunction via regulating Nrf2/Sirt3 signaling pathway.

Doxorubicin (DOX) is a potent chemotherapeutic drug but the clinical use was limited by its dose-dependent cardiotoxicity. Pinocembrin (PCB), a flavonoid originally isolated from honeybee propolis and rhizomes of Boesenbergia pandurate displays diverse biological activities. However, the role of PCB in DOX-induced cardiac injury and its underlying molecular mechanism are not fully elucidated. The present study was designed to evaluate the protective role of PCB in a DOX-induced cardiotoxicity in vivo and in vitro. Our results revealed that PCB administration greatly improved cardiac function and reduced cardiac fibrosis manifested by LVEF, LVFS, LVIDd, LVIDs, and myocardial fibrotic area which were impaired by DOX treatment. The cardiac injury evidenced by LDH and CK-MB activities were reduced while the levels of IL-1ß and IL-18 were decreased following PCB treatment compared to DOX-treated mice. Mechanically, our present results showed that PCB significantly inhibited DOX-induced cardiomyocyte pyroptosis via activating Nrf2/Sirt3 signal pathway. Furthermore, the inhibition of Nrf2 in H9c2 cells abolished the protective role of PCB against DOX-induced cell toxicity, which was at least partly via upregulation of NLRP3-mediated pyroptosis. In conclusion, our study clearly demonstrated that PCB reduced cardiomyocyte pyroptosis to protect hearts from DOX-induced cardiotoxicity through activation of Nrf2/Sirt3 signal pathway.

Design of a Novel Nucleus-Targeted NLS-KALA-SA Nanocarrier to Delivery Poorly Water-Soluble Anti-Tumor Drug for Lung Cancer Treatment.

In this study, we designed a novel nucleus-targeted nanocarrier (NLS-KALA-SA, NKSN) consisting of Kala peptide (KALA), nuclear localization signal (NLS) and stearic acid (SA) using Fmoc solid phase synthesis method. We chose Curcumin (CUR), Paclitaxel (PTX), Ginsenoside compound K(CK) as models of poorly water-soluble antitumor drugs, The drugs loaded NLS-KALA-SA nanoparticles (CUR/NKSN, PTX/NKSN, CK/NKSN) were obained by the dialysis method, their physicochemical properties were determined and antitumor activity were evaluated. The NLS-KALA-SA nanoparticles were spherical shaped with an average size of 76.4 ± 7.6 mm and a zeta potential of 43.7 ± 5.8 mV. The drug-loaded NLS-KALA-SA nanoparticles were above 86.1% and 17.1% in entrapment efficiency and drug loading capacity, and had sustained drug release behavior. Biodistribution and cellular uptake study exhibited that PTX/NKSN mainly distributed in tumor site of A549-bearing mice, and coumarin-6(C6) loaded NLS-KALA-SA nanoparticle (C6/NKSN) was predominantly accumulated in the nucleus of A549 cells. Western blot analysis indicated that PTX/NKSN could more remarkably inhibit Bcl-2 expression and enhance the expression of Bax and Caspase-3 as compared to the controls in A549 cells. Cell apoptosis and antitumor activity study showed that PXT/NKSN could more obviously induce apoptosis of A549 cells compared with free PXT, the PTX/NKSN administration was more effective than free PTX for lung cancer treatment and displayed mild toxicity in A549-bearing mice. The results demonstrates that the NLS-KALA-SA nanoparticles system could enhance the antitumor effects of the encapsulated drug and reduce tissue toxicity due to its long circulating properties and tumor targeting, which might provide a promising strategy for lung cancer treatment.

Visible light promoted deaminative difluoroalkylation of aliphatic amines with difluoroenoxysilanes.

A visible light promoted deaminative strategy for the difluoroalkylation reaction utilizing pyridinium-activated aliphatic primary amines and difluoroenoxysilane as substrates has been developed. This protocol is characteriazed by its mild reaction conditions and broad substrate scope, which converted a diverse array of amine-containing molecules to the alkyl-CF2COPh products. Moreover, the resulting products can be easily transformed into a vast array of structurally novel and interesting difluoro-containing moieties, therefore providing a facile route for applications in medicinal chemistry and the life sciences.