Relay Annulation of Ammonium Ylides with Oxindole-Derived α,ß-Unsaturated Ketimines: Catalytic Construction of Spiro-polycyclic Oxindoles.

An ammonium ylide-based relay annulation was disclosed, which uses DABCO as the catalyst and oxindole-derived α,ß-unsaturated ketimines and γ-bromo-crotonates as the starting materials. This method enables the rapid assembly of a series of structurally novel spiro-polycyclic oxindoles containing a bicyclo[4.1.0]heptane moiety through simultaneous generation of three new bonds and two rings in one step under mild reaction conditions.

1,5-Hydrogen atom transfer of α-iminyl radical cations: a new platform for relay annulation for pyridine derivatives and axially chiral heterobiaryls.

The exploitation of new reactive species and novel transformation modes for their synthetic applications have significantly promoted the development of synthetic organic methodology, drug discovery, and advanced functional materials. α-Iminyl radical cations, a class of distonic ions, exhibit great synthetic potential for the synthesis of valuable molecules. For their generation, radical conjugate addition to α,ß-unsaturated iminium ions represents a concise yet highly challenging route, because the in situ generated species are short-lived and highly reactive and they have a high tendency to cause radical elimination (ß-scission) to regenerate the more stable iminium ions. Herein, we report a new transformation mode of the α-iminyl radical cation, that is to say, 1,5-hydrogen atom transfer (1,5-HAT). Such a strategy can generate a species bearing multiple reactive sites, which serves as a platform to realize (asymmetric) relay annulations. The present iron/secondary amine synergistic catalysis causes a modular assembly of a broad spectrum of new structurally fused pyridines including axially chiral heterobiaryls, and exhibits good functional group tolerance. A series of mechanistic experiments support the α-iminyl radical cation-induced 1,5-HAT, and the formation of several radical species in the relay annulations. Various synthetic transformations of the reaction products demonstrate the usefulness of this relay annulation protocol for the synthesis of significant molecules.

Safety and efficacy of percutaneous electrocoagulation haemostasis in the treatment of grade IV haemorrhagic cystitis after allogeneic haematopoietic stem cell transplantation in children: a retrospective analysis.

BACKGROUND: To investigate the efficacy and safety of endoscopic electrocoagulation haemostasis via a percutaneous transhepatic approach for the treatment of grade IV haemorrhagic cystitis (HC) after allogeneic haematopoietic stem cell transplantation (allo-HSCT) in children. METHODS: The clinical data of 14 children with severe HC, who were admitted to Hebei Yanda Hospital between July 2017 and January 2020, were analysed retrospectively. There were nine males and five females, with an average age of 8.6 years (range: 3 to 13 years). After an average of 39.6 (7 to 96) days of conservative treatment in the hospital's haematology department, the bladders of all patients were filled with blood clots. A small 2-cm incision was made in the suprapubic area to enter the bladder and quickly clear the blood clots, and a percutaneous transhepatic approach to electrocoagulation and haemostasis was performed. RESULTS: In the 14 children, a total of 16 operations were performed, with an average operation time of 97.1 (31 to 150) min, an average blood clot of 128.1 (80 to 460) mL and an average intraoperative blood loss of 31.9 (20 to 50) mL. There were three cases of postoperative bladder spasm remission after conservative treatment. During the follow-up period of 1 to 31 months, one patient improved after one operation, 11 patients were cured after one operation, and two patients were cured after recurrent haemostasis by secondary electrocoagulation, four of whom died of postoperative non-surgical blood-related diseases and severe lung infections. CONCLUSION: Percutaneous electrocoagulation haemostasis can quickly remove blood clots in the bladders of children after allo-HSCT with grade IV HC. It is a safe and effective minimally invasive treatment.

Application of Internet+-based Tsinghua PINS Remote Tech to improve sacral neuromodulation programming procedure.

OBJECTIVE: To explore the feasibility and safety of the Tsinghua PINS Remote Tech to facilitate sacral neuromodulation programming procedure. METHOD: For 22 patients who had previously participated in the phase III clinical trial for treating overactive bladder with the Tsinghua PINS sacral neuromodulation system during several Hospital, PINS Remote Tech was applied to perform postoperative parameter adjustment in order to evaluate the safety and reliability of this new technique. Telephone surveys on Remote Tech-related questionnaires were also conducted. RESULTS: 17/22 patients underwent 26 parameter adjustments, average adjustment frequency was 1.53 times per person; the average adjustment time was 23.4 ± 5.1 min (15-32 min). The total effective rate of the Remote control was 14/17 (82.3%). 7/17 (41.1%) patients' symptoms recurrence due to not knowing how to handle patient controller, these patients were instructed on how to use it correctly through Remote Tech even without reprogramming it. Other 10 patients received reprogramming. There was no discomfort during and after parameter adjustment. The questionnaire survey showed that the remote technology saved patients' time and lowered financial costs, significantly improved patient satisfaction. All patients expressed their willingness to recommend it to other patients. CONCLUSION: The PINS Remote Tech can significantly reduce the financial cost and provide a remote reprogram control service that is as safe and reliable as outpatient program control.

Inhibition of macrophage-derived foam cell formation by ezetimibe via the caveolin-1/MAPK pathway.

Ezetimibe, a selective inhibitor of intestinal cholesterol absorption, effectively reduces plasma cholesterol, but its effect on atherosclerosis is unclear. Foam cell formation has been implicated as a key mediator during the development of atherosclerosis. The purpose of this study was to investigate the effects of ezetimibe on foam cell formation and explore the underlying mechanism. The results presented here show that ezetimibe reduces atherosclerotic lesions in apolipoprotein E deficient (apoE-/-) mice by lowering cholesterol levels. Treatment of macrophages with Chol:MßCD resulted in foam cell formation, which was concentration-dependently inhibited by the presence of ezetimibe. Mechanically, ezetimibe treatment downregulated the expression of CD36 and scavenger receptor class B1 (SR-B1), but upregulated the expression of apoE and caveolin-1 in macrophage-derived foam cells, which kept consistent with our microarray results. Moreover, treatment with ezetimibe abrogated the increase of phospho-extracellular signal regulated kinase (ERK) 1/2 and their nuclear accumulation in foam cells. Inhibition of the MAPK pathway by the MEK inhibitor PD98059 attenuated the inhibitory effect of ezetimibe on the expression of p-ERK1/2 and caveolin-1. Taken together, these results showed that ezetimibe suppressed foam cell formation via the caveolin-1/MAPK signalling pathway, suggesting that inhibition of foam cell formation might be a novel mechanism underlying the anti-atherosclerotic effect of ezetimibe.

Ezetimibe suppresses cholesterol accumulation in lipid-loaded vascular smooth muscle cells in vitro via MAPK signaling.

AIM: To investigate the mechanisms of anti-atherosclerotic action of ezetimibe in rat vascular smooth muscle cells (VSMCs) in vitro. METHODS: VSMCs of SD rats were cultured in the presence of Chol:MßCD (10 µg/mL) for 72 h, and intracellular lipid droplets and cholesterol levels were evaluated using Oil Red O staining, HPLC and Enzymatic Fluorescence Assay, respectively. The expression of caveolin-1, sterol response element-binding protein-1 (SREBP-1) and ERK1/2 were analyzed using Western blot assays. Translocation of SREBP-1 and ERK1/2 was detected with immunofluorescence. RESULTS: Treatment with Chol:MßCD dramatically increased the cellular levels of total cholesterol (TC), cholesterol ester (CE) and free cholesterol (FC) in VSMCs, which led to the formation of foam cells. Furthermore, Chol:MßCD treatment significantly decreased the expression of caveolin-1, and stimulated the expression and nuclear translocation of SREBP-1 in VSMCs. Co-treatment with ezetimibe (3 µmol/L) significantly decreased the cellular levels of TC, CE and FC, which was accompanied by elevation of caveolin-1 expression, and by a reduction of SREBP-1 expression and nuclear translocation. Co-treatment with ezetimibe dose-dependently decreased the expression of phosphor-ERK1/2 (p-ERK1/2) in VSMCs. The ERK1/2 inhibitor PD98059 (50 µmol/L) altered the cholesterol level and the expression of p-ERK1/2, SREBP-1 and caveolin-1 in the same manner as ezetimibe did. CONCLUSION: Ezetimibe suppresses cholesterol accumulation in rat VSMCs in vitro by regulating SREBP-1 and caveolin-1 expression, possibly via the MAPK signaling pathway.

Inhibition of smooth muscle cell proliferation by ezetimibe via the cyclin D1-MAPK pathway.

Proliferation of vascular smooth muscle cells (VSMCs) contributes to the development of atherosclerosis. Ezetimibe is a new lipid lowering agent that inhibits cholesterol absorption. In the present study we attempted to investigate whether ezetimibe has any effect on VSMC proliferation and the potential mechanisms involved. Our data showed ezetimibe abrogated the proliferation and migration of primary rat VSMCs induced by Chol:MßCD. Mechanically, we found that ezetimibe was capable of abolishing cyclin D1, CDK2, phospho-Rb (p-Rb), and E2F protein expressions that were upregulated by Chol:MßCD treatment. In addition, Ezetimibe was able to reverse cell cycle progression induced by Chol:MßCD, which was further supported by its down-regulation of cyclin D1 promoter activity in the presence of Chol:MßCD. Furthermore, ezetimibe abrogated the increment of phospho-ERK1/2 (p-ERK1/2) and nuclear accumulation of ERK1/2 in VSMCs induced by Chol:MßCD. Inhibition of the MAPK pathway by using ERK1/2 inhibitor PD98059 attenuated the reduction effect of ezetimibe on the expressions of phosphor-MEK1 (p-MEK1), p-ERK1/2, and cyclin D1. Taken together our data suggest that ezetimibe inhibits Chol:MßCD-induced VSMCs proliferation and leads to cell cycle arrest at the G0/G1 phase by suppressing cyclin D1 expression via the MAPK signaling pathway. These novel findings support the potential pleiotropic effect of ezetimibe in cardiovascular disease.

Anti-inflammatory activity of ezetimibe by regulating NF-κB/MAPK pathway in THP-1 macrophages.

Inflammation plays a crucial role in atherosclerosis. Monocytes/macrophages are involved in the inflammatory process during atherogenesis. Here, we performed daily gavage of ezetimibe in apolipoprotein E-deficient mice fed with a high-fat diet and found that ezetimibe administration decreased the level of C-reactive protein significantly. To investigate the potential molecular mechanism, we employed microarray analysis on the cultured macrophages treated with Chol:MßCD in the presence or absence of ezetimibe. We found that ezetimibe dramatically down-regulated the expression of the tumor necrosis factor-α (TNF-α) gene. Consistent with the microarray results, TNF-α protein levels were inhibited by ezetimibe. Moreover, ezetimibe suppressed the promoter activity of TNF-α but not TNF-α lacking the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) binding domain in THP-1 cells treated with phorbol myristate acetate and Chol:MßCD. Furthermore, treatment of THP-1 macrophages with ezetimibe resulted in the degradation of IκB and subsequently inhibited nuclear translocation of NF-κB and its transcriptional activity. Inhibition of the mitogen-activated protein kinase (MAPK) pathway using PD98059 attenuated the reduction effect of ezetimibe on the expression of NF-κB. Collectively, our results demonstrated that the anti-inflammatory properties of ezetimibe in THP-1 macrophages are, at least in part, through suppression of NF-κB activation via the MAPK pathway. These data provide direct evidence for the potential application of ezetimibe in the prevention and treatment of inflammatory diseases.

Effects and underlying mechanisms of curcumin on the proliferation of vascular smooth muscle cells induced by Chol:MbetaCD.

Proliferation of vascular smooth muscle cells (VSMCs) contributes to the development of various cardiovascular diseases. Curcumin, extracted from Curcumae longae, has been shown a variety of beneficial effects on human health, including anti-atherosclerosis by mechanisms poorly understood. In the present study, we attempted to investigate whether curcumin has any effect on VSMCs proliferation and the potential mechanisms involved. Our data showed curcumin concentration-dependently abrogated the proliferation of primary rat VSMCs induced by Chol:MbetaCD. To explore the underlying cellular and molecular mechanisms, we found that curcumin was capable of restoring caveolin-1 expression which was reduced by Chol:MbetaCD treatment. Moreover, curcumin abrogated the increment of phospho-ERK1/2 and nuclear accumulation of ERK1/2 in primary rat VSMCs induced by Chol:MbetaCD, which led to a suppression of AP-1 promoter activity stimulated by Chol:MbetaCD. In addition, curcumin was able to reverse cell cycle progression induced by Chol:MbetaCD, which was further supported by its down-regulation of cyclinD1 and E2F promoter activities in the presence of Chol:MbetaCD. Taking together, our data suggest curcumin inhibits Chol:MbetaCD-induced VSMCs proliferation via restoring caveolin-1 expression that leads to the suppression of over-activated ERK signaling and causes cell cycle arrest at G1/S phase. These novel findings support the beneficial potential of curcumin in cardiovascular disease.

Curcumin inhibits cellular cholesterol accumulation by regulating SREBP-1/caveolin-1 signaling pathway in vascular smooth muscle cells.

AIM: To investigate the protective effect and the possible mechanism of curcumin on anti-atherosclerosis. METHODS: Morphological changes of atherosclerotic lesions taken from apoE knockout (apoE-/-) mice were determined by hematoxylin- eosin staining. Intracellular lipid droplets and lipid levels were assayed by oil red O staining and HPLC. The protein expression of caveolin-1 was quantified by Western blotting. Translocation and the expression of sterol response element-binding protein-1 (SREBP-1) were indirectly detected by an immunofluorescence analysis. RESULTS: The administration of 20 mg. kg(-1 ). d(-1 )curcumin to apoE-/- mice for 4 months induced a 50% reduction of atherosclerotic lesions and yielded a 5- fold increase in the caveolin-1 expression level as compared to the model group. Rat vascular smooth muscle cells (VSMC) pretreated with 50 mg/L ox-lipid density lipoprotein(ox-LDL) for 48 h increased cellular lipid contents, and stimulated SREBP-1 translocation, but decreased the caveolin-1 expression level. Lipid-loaded cells exposed to curcumin at various concentrations (12.5, 25, and 50 micromol/L) for different durations (0, 6, 12, 24, and 48 h) significantly diminished the number and area of cellular lipid droplets, total cholesterol, cholesterol ester, and free cholesterol accompanying the elevation of the caveolin-1 expression level (approximately 3-fold); the translocation of SREBP-1 from the cytoplasm to the nucleus was inhibited compared with the models. Lipid-loaded VSMC exposed to N-acetyl- Leu-Leu-norleucinal, a SREBP-1 protease inhibitor, showed increased nuclear translocation of SREBP-1, reduced caveolin-1 expression level, and upregulated cellular lipid levels. CONCLUSION: Curcumin inhibits ox-LDL-induced cholesterol accumulation in cultured VSMC through increasing the caveolin-1 expression via the inhibition of nuclear translocation of SREBP-1.

Probucol mediates vascular remodeling after percutaneous transluminal angioplasty via down-regulation of the ERK1/2 signaling pathway.

Although probucol is known to prevent restenosis by regulating vascular remodeling after percutaneous transluminal coronary angioplasty, the mechanisms remain unclear. The present study was designed to investigate whether probucol mediates vascular remodeling via the extracellular signal-regulated kinase 1/2 (ERK1/2) signalling pathway. A rabbit restenosis model was used, in which the New Zealand white rabbits received angioplasty with a 3.5 F angioplasty balloon catheter and the proliferation and migration of smooth muscle cells (SMCs) was induced by oxidized low-density lipoprotein (ox-LDL). We evaluated several vascular remodeling parameters and found that probucol prevented lumen restenosis and mediated expansive remodeling with a remodeling index greater than 1 and that the proliferation and migration of SMCs was inhibited. Based on Western blot analyses, probucol decreased the expression of phospho-mitogen-activated protein kinase kinases 1 (p-MEK1) and phospho-ERK1/2 and enhanced the expression of mitogen-activated protein (MAP) kinase phosphatase-1 (MKP-1) and caveolin-1. Cells treated with the MEK1 inhibitor PD98059 demonstrated a remarkable suppression of the effects of probucol. Furthermore, immunofluorescence analysis showed that probucol inhibited the activation of ERK1/2 by preventing its translocation to the nucleus. It was also found that c-myc expression in aortic tissue after angioplasty and the activator protein 1 (AP1) activity in SMCs induced by ox-LDL were decreased with probucol treatment. In conclusion, probucol mediated vascular remodeling to prevent restenosis after angioplasty by down-regulating the ERK1/2 signaling pathway.

Anti-apoptotic effects of probucol are associated with downregulation of Daxx expression in THP-1 macrophage.

AIM: To study the relationship between Daxx expression and the antiapoptotic effects of probucol in THP-1 macrophage. MATERIALS AND METHODS: Apoptosis of THP-1 derived macrophages was induced by exposure to oxidized low density lipoprotein (oxLDL). The development of apoptosis was determined by flow cytometry analysis and nucleic acid-binding dye acridin orange. Reverse transcriptase-polymerase chain reaction (RT-PCR), Western blotting and indirect immunofluorescence were used to evaluate the expression of Daxx and caspase-3 at both mRNA and protein level. RESULTS: As expected, THP-1 macrophages exposed to 100 mg/l oxLDL for 48 h exhibited typical morphologic changes of apoptosis, including condensed chromatin and shrunken nucleus. oxLDL treatment markedly increased Daxx expression in a time- and dose-dependent manner, and facilitated Daxx translocation from cytoplasm to nucleus. The percentage of cells with Daxx in nuclei was significantly increased from 8 to 59%. Treatment with probucol (50 micromol/l) for 4 h prior to exposure to oxLDL significantly inhibited Daxx expression and THP-1 macrophage apoptosis by 61.3%. Furthermore, oxLDL enhanced caspase-3 expression with increased mRNA and protein levels, but without obvious change in translocation of caspase-3 (the cells with nuclear Daxx: 14 vs 8%). In contrast, probucol attenuated oxLDL-stimulated caspase-3 expression in THP-1 macrophages. CONCLUSION: OxLDL-induced apoptosis of THP-1 macrophage is associated with Daxx up-regulation; while inhibition of apoptosis by probucol is related to decreased Daxx expression and nuclear translocation.