Investigating an outbreak of equine viral arteritis at two connected premises.

In early 2019, four stallions in the south of England tested positive for equine viral arteritis following routine prebreeding screening. Here, a team from Defra and the APHA describe the epidemiological investigation that was carried out to determine the origin of infection and the potential for its transmission across the country.

Prevention of radiotherapy-induced arterial inflammation by interleukin-1 blockade.

AIMS: Radiotherapy-induced cardiovascular disease is an emerging problem in a growing population of cancer survivors where traditional treatments, such as anti-platelet and lipid-lowering drugs, have limited benefits. The aim of the study was to investigate vascular inflammatory patterns in human cancer survivors, replicate the findings in an animal model, and evaluate whether interleukin-1 (IL-1) inhibition could be a potential treatment. METHODS AND RESULTS: Irradiated human arterial biopsies were collected during microvascular autologous free tissue transfer for cancer reconstruction and compared with non-irradiated arteries from the same patient. A mouse model was used to study the effects of the IL-1 receptor antagonist, anakinra, on localized radiation-induced vascular inflammation. We observed significant induction of genes associated with inflammasome biology in whole transcriptome analysis of irradiated arteries, a finding supported by elevated protein levels in irradiated arteries of both, pro-caspase and caspase-1. mRNA levels of inflammasome associated chemokines CCL2, CCL5 together with the adhesion molecule VCAM1, were elevated in human irradiated arteries as was the number of infiltrating macrophages. A similar pattern was reproduced in Apoe-/- mouse 10 weeks after localized chest irradiation with 14 Gy. Treatment with anakinra in irradiated mice significantly reduced Ccl2 and Ccl5 mRNA levels and expression of I-Ab. CONCLUSION: Anakinra, administered directly after radiation exposure for 2 weeks, ameliorated radiation induced sustained expression of inflammatory mediators in mice. Further studies are needed to evaluate IL-1 blockade as a treatment of radiotherapy-induced vascular disease in a clinical setting.

Effects of pitavastatin and pravastatin on markers of immune activation and arterial inflammation in HIV.

OBJECTIVE: Persistent immune activation is thought to contribute to increased cardiovascular disease risk in HIV and statins may help modulate systemic immune activation. We aimed to compare the effects of two key statins on markers of systemic immune activation and arterial inflammation in the HIV population. DESIGN: Double-blind, active-controlled, parallel-group comparative trial performed in 45 sites. METHODS: Two hundred and fifty-two antiretroviral therapy-treated HIV-infected participants with dyslipidemia were randomized (1 : 1) to pitavastatin 4 mg daily vs. pravastatin 40 mg daily in the HIV-infected patieNts and TREatment with PItavastatin vs. pravastatin for Dyslipidemia (INTREPID) trial. In this analysis of the INTREPID trial, we assessed markers of immune activation and arterial inflammation using a modified intent-to-treat population. This trial is registered with ClinicalTrials.gov (NCT01301066). RESULTS: One hundred and twenty-six participants were randomized to receive pitavastatin and 126 to pravastatin. Ninety-nine participants in the pitavastatin group and 91 participants in the pravastatin group completed the study. Median age was 50 (45, 56) years [median (interquartile range)]. Baseline, low-density lipoprotein-cholestrol (LDL-C) was 153 (135, 171) mg/dl, log HIV-1 viral load was 1.1 ±â€Š0.2 copies/ml, and CD4 cell count was 580 (439, 794) cells/µl. At week 52, the pitavastatin group had a significantly greater reduction (% change) compared with pravastatin in soluble CD14 (sCD14), (-10.0 vs. 0.6%, P = 0.02), oxidized LDL (oxLDL) (-26.9 vs. -17.5%, P = 0.02), and lipoprotein-associated phospholipase 2 (Lp-PLA2) (-26.6 vs. -15.5%, P = 0.005) (pitavastatin vs. pravastatin). CONCLUSION: Fifty-two weeks of pitavastatin 4 mg daily (vs. pravastatin 40 mg daily) led to a greater reduction in select markers of immune activation and arterial inflammation (sCD14, oxLDL, and LpPLA2) among HIV-infected participants. Further work is needed to assess whether immune-modulatory effects of pitavastatin reduce cardiovascular disease risk in HIV.

Heart rate reduction with ivabradine promotes shear stress-dependent anti-inflammatory mechanisms in arteries.

Blood flow generates wall shear stress (WSS) which alters endothelial cell (EC) function. Low WSS promotes vascular inflammation and atherosclerosis whereas high uniform WSS is protective. Ivabradine decreases heart rate leading to altered haemodynamics. Besides its cardio-protective effects, ivabradine protects arteries from inflammation and atherosclerosis via unknown mechanisms. We hypothesised that ivabradine protects arteries by increasing WSS to reduce vascular inflammation. Hypercholesterolaemic mice were treated with ivabradine for seven weeks in drinking water or remained untreated as a control. En face immunostaining demonstrated that treatment with ivabradine reduced the expression of pro-inflammatory VCAM-1 (p<0.01) and enhanced the expression of anti-inflammatory eNOS (p<0.01) at the inner curvature of the aorta. We concluded that ivabradine alters EC physiology indirectly via modulation of flow because treatment with ivabradine had no effect in ligated carotid arteries in vivo, and did not influence the basal or TNFα-induced expression of inflammatory (VCAM-1, MCP-1) or protective (eNOS, HMOX1, KLF2, KLF4) genes in cultured EC. We therefore considered whether ivabradine can alter WSS which is a regulator of EC inflammatory activation. Computational fluid dynamics demonstrated that ivabradine treatment reduced heart rate by 20 % and enhanced WSS in the aorta. In conclusion, ivabradine treatment altered haemodynamics in the murine aorta by increasing the magnitude of shear stress. This was accompanied by induction of eNOS and suppression of VCAM-1, whereas ivabradine did not alter EC that could not respond to flow. Thus ivabradine protects arteries by altering local mechanical conditions to trigger an anti-inflammatory response.

Dipeptidyl-peptidase-4 inhibitor, alogliptin, attenuates arterial inflammation and neointimal formation after injury in low-density lipoprotein (LDL) receptor-deficient mice.

BACKGROUND: The results of recent studies suggest that dipeptidyl-peptidase-4 inhibitors have antiatherogenic effects. However, whether or not dipeptidyl-peptidase-4 inhibitors could suppress arterial inflammation and intimal hyperplasia after injury remains undetermined. The present study aims to clarify the anti-inflammatory effects of the dipeptidyl-peptidase-4 inhibitor, alogliptin (AGP), on the arteries of atherogenic low-density lipoprotein receptor-deficient (LKO) mice. METHODS AND RESULTS: We compared intimal hyperplasia in LKO mice 2 weeks after femoral artery injury using an external vascular cuff model. All mice received oral injection of AGP (20 mg/kg per day) or normal saline (control) once daily for 14 days. Fasting blood sugar levels, serum cholesterol levels, or blood pressure did not significantly differ between the 2 groups. Plasma levels of active glucagon-like peptide-1 were higher in the AGP than in the control LKO mice (22.2±1.9 versus 15.6±0.9 pg/mL; P<0.05). Compared with saline, AGP significantly reduced intimal hyperplasia (1087±127 versus 1896±140 µm(2); P<0.001) as well as the intima/media ratio (0.08±0.01 versus 0.16±0.02; P<0.001). Immunostaining showed that AGP reduced proliferating cells (proliferating cell nuclear antigen-positive nuclei; P<0.001), percent smooth-muscle cell area (α-SMA-positive cells; P<0.001), inflammatory cells infiltration (lymphocyte antigen 6 complex-positive cells; P<0.05), tumor necrosis factor-α expression (P<0.05), and percent phospho-NF-κB-positive cell compared with saline. Levels of tumor necrosis factor -α (0.5-fold P<0.05), monocyte chemoattractant protein 1 (0.3-fold P<0.01), and interleukin-1ß (0.2-fold P<0.05) mRNA were lower in the injured arteries of the AGP than in the control group. CONCLUSIONS: AGP appeared to suppress neointimal formation by inhibiting inflammation, independently of its effects on glucose or cholesterol metabolism in atherogenic LKO mice.

Interleukin-1 receptor antagonist originating from bone marrowderived cells and non-bone marrow-derived cells helps to suppress arterial inflammation and reduce neointimal formation after injury.

AIM: Interleukin-1 receptor antagonist (IL-1Ra) negatively regulates IL-1 signaling by blocking the functional receptor. We previously demonstrated that IL-1Ra-deficient (IL-1Ra-/-) mice exhibit marked neointimal formation after injury. IL-1Ra is expressed on bone marrow (BM)-derived cells as well as non-BM intrinsic arterial cells. However, the importance of various cell types as sources of IL-1Ra remains unknown. The aim of this study was to test the hypothesis that IL-1Ra originating from BM-derived cells and non-BM intrinsic cells helps to suppress both inflammation and neointimal formation after vascular injury using a model of BM cell transplantation (BMT). METHODS: In order to determine the contribution of IL-1Ra-deficient (Ra-/-) and wild-type (WT) BM cells to neointimal formation, we developed four types of BM chimeric mice (BMT(WT→WT) (n=12), BMT(Ra-/-→WT) (n=12), BMT(WT→Ra-/-) (n=12) and BMT(Ra-/-→Ra-/-) (n=12)). At four weeks after BMT, we induced vascular injury by placing a non-occlusive cuff around the femoral artery. Histological analyses were subsequently performed two weeks after injury. RESULTS: Neointimal formation was decreased in the BMT(WT→Ra-/-) mice compared with that observed in the BMT(Ra-/-→Ra-/-) mice (p＜0.001), but significantly more so in the BMT(Ra-/-→WT) (p＜0.01) and BMT(WT→WT) (p＜0.01) mice. In contrast, the neointimal formation in the BMT(Ra-/-→WT) mice was significantly increased compared with that noted in the BMT(WT→WT) mice (p＜0.05). In addition, immunostaining revealed that Mac3-positive areas were significantly increased in the BMT(Ra-/-→Ra-/-) mice compared with those seen in the other three groups (p＜0.001), with a significantly decreased percentage of alpha-SMA-positive areas in the neointima in the BMT(Ra-/-→Ra-/-) mice compared with that found in the remaining groups (p＜0.001). Furthermore, IL-1Ra staining demonstrated the IL-1Ra expression in several inflammatory cells in the adventitia in the BMT(WT→WT) and BMT(WT→Ra-/-) mice, compared to the neointima in the BMT(WT→WT) and BMT(Ra-/-→WT) mice. CONCLUSIONS: The IL-1Ra present in BM-derived cells and non-BM cells helps to suppress arterial inflammation, resulting in decreased neointimal formation after injury. These findings shed new light on the mechanisms underlying the development of atherosclerosis and restenosis after angioplasty.

Inhibition of Notch1 signaling reduces abdominal aortic aneurysm in mice by attenuating macrophage-mediated inflammation.

OBJECTIVE: Activation of inflammatory pathways plays a critical role in the development of abdominal aortic aneurysms (AAA). Notch1 signaling is a significant regulator of the inflammatory response; however, its role in AAA is unknown. METHODS AND RESULTS: In an angiotensin II-induced mouse model of AAA, activation of Notch1 signaling was observed in the aortic aneurysmal tissue of Apoe(-/-) mice, and a similar activation of Notch1 was observed in aneurysms of humans undergoing AAA repair. Notch1 haploinsufficiency significantly reduced the incidence of AAA in Apoe(-/-) mice in response to angiotensin II. Reconstitution of bone marrow-derived cells from Notch1(+/-);Apoe(-/-) mice (donor) in lethally irradiated Apoe(-/-) mice (recipient) decreased the occurrence of aneurysm. Flow cytometry and immunohistochemistry demonstrated that Notch1 haploinsufficiency prevented the influx of inflammatory macrophages at the aneurysmal site by causing defects in macrophage migration and proliferation. In addition, there was an overall reduction in the inflammatory burden in the aorta of the Notch1(+/-);Apoe(-/-) mice compared with the Apoe(-/-) mice. Last, pharmacological inhibition of Notch1 signaling also prevented AAA formation and progression in Apoe(-/-) mice. CONCLUSIONS: Our data suggest that decreased levels of Notch1 protect against the formation of AAA by preventing macrophage recruitment and attenuating the inflammatory response in the aorta.

Chronic matrix metalloproteinase inhibition retards age-associated arterial proinflammation and increase in blood pressure.

Age-associated arterial remodeling involves arterial wall collagen deposition and elastin fragmentation, as well as an increase in arterial pressure. This arterial remodeling is linked to proinflammatory signaling, including transforming growth factor-ß1, monocyte chemoattractant protein 1, and proendothelin 1, activated by extracellular matrix metalloproteinases (MMPs) and orchestrated, in part, by the transcriptional factor ets-1. We tested the hypothesis that inhibition of MMP activation can decelerate the age-associated arterial proinflammation and its attendant increase in arterial pressure. Indeed, chronic administration of a broad-spectrum MMP inhibitor, PD166739, via a daily gavage, to 16-month-old rats for 8 months markedly blunted the expected age-associated increases in arterial pressure. This was accompanied by the following: (1) inhibition of the age-associated increases in aortic gelatinase and interstitial collagenase activity in situ; (2) preservation of the elastic fiber network integrity; (3) a reduction of collagen deposition; (4) a reduction of monocyte chemoattractant protein 1 and transforming growth factor-ß1 activation; (5) a diminution in the activity of the profibrogenic signaling molecule SMAD-2/3 phosphorylation; (6) inhibition of proendothelin 1 activation; and (7) downregulation of expression of ets-1. Acute exposure of cultured vascular smooth muscle cells in vitro to proendothelin 1 increased both the transcription and translation of ets-1, and these effects were markedly reduced by MMP inhibition. Furthermore, infection of vascular smooth muscle cells with an adenovirus harboring a full-length ets-1 cDNA increased activities of both transforming growth factor-ß1 and monocyte chemoattractant protein 1. Collectively, our results indicate that MMP inhibition retards age-associated arterial proinflammatory signaling, and this is accompanied by preservation of intact elastin fibers, a reduction in collagen, and blunting of an age-associated increase in blood pressure.

Cysteine, histidine and glycine exhibit anti-inflammatory effects in human coronary arterial endothelial cells.

The activation of nuclear factor-kappa B (NF-κB) in vascular endothelial cells may be involved in vascular pathogeneses such as vasculitis or atherosclerosis. Recently, it has been reported that some amino acids exhibit anti-inflammatory effects. We investigated the inhibitory effects of a panel of amino acids on cytokine production or expression of adhesion molecules that are involved in inflammatory diseases in various cell types. The activation of NF-κB was determined in human coronary arterial endothelial cells (HCAECs) because NF-κB modulates the production of many cytokines and the expression of adhesion molecules. We examined the inhibitory effects of the amino acids cysteine, histidine and glycine on the induction of NF-κB activation, expression of CD62E (E-selectin) and the production of interleukin (IL)-6 in HCAECs stimulated with tumour necrosis factor (TNF)-α. Cysteine, histidine and glycine significantly reduced NF-κB activation and inhibitor κBα (IκBα) degradation in HCAECs stimulated with TNF-α. Additionally, all the amino acids inhibited the expression of E-selectin and the production of IL-6 in HCAECs, and the effects of cysteine were the most significant. Our results show that glycine, histidine and cysteine can inhibit NF-κB activation, IκBα degradation, CD62E expression and IL-6 production in HCAECs, suggesting that these amino acids may exhibit anti-inflammatory effects during endothelial inflammation.

Depletion of B2 but not B1a B cells in BAFF receptor-deficient ApoE mice attenuates atherosclerosis by potently ameliorating arterial inflammation.

We have recently identified conventional B2 cells as atherogenic and B1a cells as atheroprotective in hypercholesterolemic ApoE(-/-) mice. Here, we examined the development of atherosclerosis in BAFF-R deficient ApoE(-/-) mice because B2 cells but not B1a cells are selectively depleted in BAFF-R deficient mice. We fed BAFF-R(-/-) ApoE(-/-) (BaffR.ApoE DKO) and BAFF-R(+/+)ApoE(-/-) (ApoE KO) mice a high fat diet (HFD) for 8-weeks. B2 cells were significantly reduced by 82%, 81%, 94%, 72% in blood, peritoneal fluid, spleen and peripheral lymph nodes respectively; while B1a cells and non-B lymphocytes were unaffected. Aortic atherosclerotic lesions assessed by oil red-O stained-lipid accumulation and CD68+ macrophage accumulation were decreased by 44% and 50% respectively. B cells were absent in atherosclerotic lesions of BaffR.ApoE DKO mice as were IgG1 and IgG2a immunoglobulins produced by B2 cells, despite low but measurable numbers of B2 cells and IgG1 and IgG2a immunoglobulin concentrations in plasma. Plasma IgM and IgM deposits in atherosclerotic lesions were also reduced. BAFF-R deficiency in ApoE(-/-) mice was also associated with a reduced expression of VCAM-1 and fewer macrophages, dendritic cells, CD4+ and CD8+ T cell infiltrates and PCNA+ cells in lesions. The expression of proinflammatory cytokines, TNF-α, IL1-ß and proinflammatory chemokine MCP-1 was also reduced. Body weight and plasma cholesterols were unaffected in BaffR.ApoE DKO mice. Our data indicate that B2 cells are important contributors to the development of atherosclerosis and that targeting the BAFF-R to specifically reduce atherogenic B2 cell numbers while preserving atheroprotective B1a cell numbers may be a potential therapeutic strategy to reduce atherosclerosis by potently reducing arterial inflammation.

Novel TNF-α receptor 1 antagonist treatment attenuates arterial inflammation and intimal hyperplasia in mice.

AIM: Tumor necrosis factor receptor 1 (TNFR1) participates importantly in arterial inflammation in genetically altered mice; however it remains undetermined whether a selective TNFR1 antagonist inhibits arterial inflammation and intimal hyperplasia. This study aimed to determine the effect and mechanism of a novel TNFR1 antagonist in the suppression of arterial inflammation. METHODS: We investigated intimal hyperplasia in IL-1 receptor antagonist-deficient mice two weeks after inducing femoral artery injury in an external vascular cuff model. All mice received intraperitoneal injections of TNFR1 antagonist (PEG-R1antTNF) or normal saline twice daily for 14 days. RESULTS: PEG-R1antTNF treatment yielded no adverse systemic effects, and we observed no significant differences in serum cholesterol or blood pressure in either group; however, selective PEG-R1antTNF treatment significantly reduced intimal hyperplasia (19,671±4,274 vs. 11,440±3,292 µm(2); p=0.001) and the intima/media ratio (1.86±0.43 vs. 1.34±0.36; p=0.029), compared with saline injection. Immunostaining revealed that PEG-R1antTNF inhibits Nuclear factor-κB (NF-κB), suppressing smooth muscle cell (SMC) proliferation and decreasing chemokine and adhesion molecule expression, and thus decreasing intimal hyperplasia and inflammation. CONCLUSIONS: Our data suggest that PEG-R1antTNF suppresses SMC proliferation and inflammation by inhibiting NF-κB. This study highlights the potential therapeutic benefit of selective TNFR1 antagonist therapy in preventing intimal hyperplasia and arterial inflammation.

Trichosporon fungal arteritis causing rupture of vascular anastamosis after commercial kidney transplantation: a case report and review of literature.

This is a case report of a ruptured vascular anastomosis resulting from fungal arteritis in a commercial renal transplantation. The diagnosis was made quite early posttransplantation (at the 18th posttransplant day); this was proved by histopathologic examination and culture of the vessel wall,which showed Trichosporon fungal infection. The patient underwent operation for control of the bleeding and removal of the graft and of the diseased iliac vascular segment. On reviewing the literature, we found 17 reports of fungal arteritis in solid-organ transplant recipients; our case was the first one to report Trichosporon species as the causative agent. Infection could result from surgical or graft contamination or from preexistent infection in the patient. There is a consensus that the standard of care should include removal of the graft and the diseased iliac vascular segment with an appropriate vascular graft, because simple suturing of the disrupted infected anastomosis generally ends with disastrous recurrent rupture. A high index of suspicion is required to ensure both early diagnosis and appropriate treatment to prevent tragic loss of recipient life.

ApoA-1 mimetic peptide reverses uremia-induced upregulation of pro-atherogenic pathways in the aorta.

BACKGROUND: Chronic kidney disease (CKD) results in accelerated atherosclerosis and cardiovascular disease. This is primarily mediated by oxidative stress, inflammation and dyslipidemia. By mediating reverse cholesterol transport and exerting antioxidant/anti-inflammatory actions, high-density lipoprotein (HDL) and ApoA-1 protect against atherosclerosis. Plasma Apo-1, HDL cholesterol and HDL antioxidant/anti-inflammatory activities are reduced in CKD. ApoA-1 mimetic peptides associate with and enhance antioxidant/anti-inflammatory properties of HDL. We hypothesized that long-term administration of ApoA-1 mimetic peptide, L4F, may ameliorate inflammation and oxidative stress in the conduit arteries in experimental CKD. METHODS: After 5/6 nephrectomy, rats were randomized to L4F (5 mg/kg s.c. 3 times weekly for 4 weeks) and placebo-treated groups. Sham-operated rats served as controls. RESULTS: The untreated CKD group exhibited marked lipid accumulation and upregulations of NAD(P)H oxidase subunits (gp91(phox), p22(phox), and p47(phox)), COX-2, 12-lipoxygenase, MCP-1, PAI-1, myeloperoxidase and iNOS, NFκB activation and nitrotyrosine accumulation in the thoracic aorta. L4F administration reversed or attenuated these abnormalities without altering renal function or plasma lipids. CONCLUSIONS: CKD leads to lipid accumulation and upregulation of pro-atherogenic pathways in the artery wall. These abnormalities are attenuated by ApoA-1 mimetic peptide, pointing to its protective effect in CKD. Future studies are needed to explore the effect of these peptides in CKD patients.

Administration of human immunoglobulin suppresses development of murine systemic vasculitis induced with Candida albicans water-soluble fraction: an animal model of Kawasaki disease.

We investigated the inhibitory effect of human immunoglobulin (h-Ig) on the development of coronary arteritis in a murine model of vasculitis induced with a Candida albicans water-soluble fraction (CAWS). CAWS was intraperitoneally injected to C57BL/6 mice for 5 days. Then h-Ig was administered according to various schedules. The animals were sacrificed in week 5, and the status of vasculitis in the coronary arteries and the aortic root was investigated histologically. The groups in which h-Ig was administered for 5 days from day 3 and from day 5 of the experiment showed a significant reduction in the incidence of panvasculitis. In addition, the scope and severity of the inflammation of the aortic root and the coronary arteries were reduced in both groups. In the group administered h-Ig for 5 days from day 1 and the group administered a high dose of h-Ig once on day 1 or day 3, no suppression of development of vasculitis was observed. The h-Ig acted by suppressing the generation and progression of vasculitis in this CAWS-induced murine vasculitis model.

Activation of Nrf2 in endothelial cells protects arteries from exhibiting a proinflammatory state.

OBJECTIVE: Proinflammatory mediators influence atherosclerosis by inducing adhesion molecules (eg, VCAM-1) on endothelial cells (ECs) via signaling intermediaries including p38 MAP kinase. Regions of arteries exposed to high shear stress are protected from inflammation and atherosclerosis, whereas low-shear regions are susceptible. Here we investigated whether the transcription factor Nrf2 regulates EC activation in arteries. METHODS AND RESULTS: En face staining revealed that Nrf2 was activated in ECs at an atheroprotected region of the murine aorta where it negatively regulated p38-VCAM-1 signaling, but was expressed in an inactive form in ECs at an atherosusceptible site. Treatment with sulforaphane, a dietary antioxidant, activated Nrf2 and suppressed p38-VCAM-1 signaling at the susceptible site in wild-type but not Nrf2(-/-) animals, indicating that it suppresses EC activation via Nrf2. Studies of cultured ECs revealed that Nrf2 inactivates p38 by suppressing an upstream activator MKK3/6 and by enhancing the activity of the negative regulator MKP-1. CONCLUSIONS: Nrf2 prevents ECs at the atheroprotected site from exhibiting a proinflammatory state via the suppression of p38-VCAM-1 signaling. Pharmacological activation of Nrf2 reduces EC activation at atherosusceptible sites and may provide a novel therapeutic strategy to prevent or reduce atherosclerosis.

Role of 3beta-hydroxysteroid-delta 24 reductase in mediating antiinflammatory effects of high-density lipoproteins in endothelial cells.

OBJECTIVE: The purpose of this study was to investigate the ability of high-density lipoproteins (HDLs) to upregulate genes with the potential to protect against inflammation in endothelial cells. METHODS AND RESULTS: Human coronary artery endothelial cells (HCAECs) were exposed to reconstituted HDLs (rHDLs) for 16 hours before being activated with tumor necrosis factor-alpha (TNF-alpha) for 5 hours. rHDLs decreased vascular cell adhesion molecule-1 (VCAM-1) promoter activity by 75% (P<0.05), via the nuclear factor-kappa B (NF-kappaB) binding site. rHDLs suppressed the canonical NF-kappaB pathway and decreased many NF-kappaB target genes. Suppression of NF-kappaB and VCAM-1 expression by rHDLs or native HDLs was dependent on an increase in 3beta-hydroxysteroid-Delta 24 reductase (DHCR24) levels (P<0.05). The effect of HDLs on DHCR24 is dependent on SR-BI but not ABCAI or ABCGI. Silencing DHCR24 expression increased NF-kappaB (1.2-fold, P<0.05), VCAM-1 (30-fold, P<0.05), and NF-kappaB p50 (4-fold, P<0.05) and p65 subunits (150-fold, P<0.05). TNF-alpha activation of siDHCR24-treated cells increased expression of VCAM-1 (550-fold, P<0.001) and NF-kappaB (9-fold, P<0.001) that could no longer be suppressed by rHDLs. CONCLUSIONS: Results suggest that antiinflammatory effects of rHDLs are mediated partly through an upregulation of DHCR24. These findings raise the possibility of considering DHCR24 as a target for therapeutic modulation.

Scutellarin isolated from Erigeron multiradiatus inhibits high glucose-mediated vascular inflammation.

Erigeron multiradiatus (Lindl.) Benth is a traditional Tibetan medicine herb long used to treat various diseases related to inflammation. Our previous phytochemical studies on E. multiradiatus resulted in the isolation of scutellarin, which is a known flavone glucuronide with comprehensive pharmacological actions. In present study, we investigated the inhibition action of scutellarin on high glucose-induced vascular inflammation in human endothelial cells (ECV304 cells). Consistent with previous reports, exposure of ECV304 cells to high glucose for 24 h caused an increase of intercellular adhesion molecule-1 (ICAM-1) and monocyte chemoattractant protein 1 (MCP-1), and promoted cell adhesion between monocyte and ECV304 cells. However, pretreatment with scutellarin (0.1 and 1 microM) reversed these effects in a concentration-dependent manner. Scutellarin was able to inhibit the activation of NF-kappaB induced by high glucose in ECV304 cells. Furthermore, although oral administration of scutellarin (10 and 50 mg/kg) did not produce significant antihyperglycemic action, it lowered the serum MCP-1 levels significantly in alloxan-induced diabetic mice. Therefore, our results suggest that scutellarin has anti-inflammation effect that may afford some protection against hyperglycemia-induced vascular inflammatory both in vitro and in vivo.

Iliac anastomotic stenting with a biodegradable poly-L-lactide stent: a preliminary study after 1 and 6 weeks.

PURPOSE: To assess the technical feasibility, thrombogenicity, and biocompatibility of a new biodegradable poly-L-lactic acid (PLLA) anastomotic stent. METHODS: A polytetrafluoroethylene bifurcated graft was implanted in 17 pigs through a midline abdominal incision. After transverse graft incision, 17 316L stainless steel stents and 17 PLLA stents were randomly implanted at both iliac anastomotic sites and deployed with a 6-mm balloon under direct vision without angiography. Intended follow-up was 1 week in 6 pigs receiving oral acetylsalicylic acid (ASA) and in 7 pigs receiving ASA/clopidogrel; 4 pigs receiving ASA/clopidogrel were followed for 6 weeks. At the end of the study, the segments containing the stents were surgically explanted and processed for histology to measure the mean luminal diameter, intimal thickness, and the vascular injury and inflammation scores. RESULTS: Initial technical success of stent placement was achieved in all animals without rupture of the suture. Two pigs died (unrelated to the stent) at 3 days after operation (1 in groups A and B). At 1 week, all PLLA stents showed thrombotic occlusion with the use of ASA alone. In contrast, all PLLA stents remained patent with concurrent administration of ASA/clopidogrel. All metal stents were patent regardless of the antiplatelet regimen. The mean luminal diameter of patent PLLA stents (4.13+/-0.17 mm) was comparable to metal stents (4.27+/-0.35 mm, p=0.78) at 1 week, but significantly diminished at 6 weeks (3.21+/-0.44 versus 4.19+/-0.18 mm, p=0.005). Histological analysis showed no signs of excessive recoil. PLLA stents induced a higher inflammation score (1.79+/-0.56) and more intimal hyperplasia (0.34+/-0.11 mm) compared to metal stents [1.27+/-0.44 mm (p<0.001) and 0.18+/-0.04 mm (p=0.006), respectively] at 6 weeks. Vascular injury was comparable between PLLA and metal stents. CONCLUSION: Biodegradable PLLA stents showed higher thrombogenicity and reduced patency compared to metal stents during early follow-up. Although ASA and clopidogrel prevented thrombotic occlusion, the increased inflammatory response and neointima formation remain major concerns of PLLA stents. A solution to this problem might be the incorporation of anti-inflammatory drugs into the PLLA stent.

RAGE modulates vascular inflammation and atherosclerosis in a murine model of type 2 diabetes.

Previous studies demonstrated that induction of diabetes with streptozotocin (stz) accelerated atherosclerosis in hyperlipidemic apo E null (-/-) mice. Blockade of the Receptor for Advanced Glycation Endproducts (RAGE) in those animals suppressed acceleration of atherosclerotic lesion area, in a manner independent of changes in levels of glucose, insulin or lipids. In the present studies, we extended these concepts to a murine model of type 2 diabetes, and bred apo E -/- mice into the db/db background. Db/db mice are a model of obesity and insulin resistance-mediated hyperglycemia. Compared to apo E -/- m/db (non-diabetic) mice, apo E -/- db/db (diabetic) mice displayed accelerated atherosclerosis at the aortic sinus. Consistent with an important role for RAGE in this process, administration of soluble (s) RAGE, the extracellular ligand-binding domain of RAGE, resulted in significantly reduced atherosclerotic lesion area in a glycemia- and lipid-independent manner. In parallel, apo E -/- db/db mice displayed RAGE-dependent enhanced expression of Vascular Cell Adhesion Molecule-1, tissue factor and matrix metalloproteinase (MMP)-9 antigen/activity in aortae compared to non-diabetic animals. In addition, consistent with the premise that upregulation of RAGE ligands and RAGE occurs even in the non-diabetic, hyperlipidemic state, albeit to lesser degrees than in diabetes, administration of sRAGE to apo E -/- m/db mice resulted in decreased atherosclerotic lesion area at the aortic sinus. Taken together, these findings establish a new murine model for the study of atherosclerosis in type 2 diabetes and highlight important roles for RAGE in proatherogenic mechanisms in hyperglycemia triggered by insulin resistance.

Impact of HIV and highly active antiretroviral therapy on leukocyte adhesion molecules, arterial inflammation, dyslipidemia, and atherosclerosis.

Highly active antiretroviral therapy (HAART) has greatly extended the lives of people infected with the human immunodeficiency virus (HIV). This reduced risk of early death from opportunistic infections or other sequelae of HIV infection, however, means that other possible causes of death emerge. Myocardial infarction has become a matter of particular concern. Two of the main sources of cardiovascular disease in this population are believed to be vascular inflammation and dyslipidemia. We review the evidence for this hypothesis and discuss the relationship of HIV to vascular inflammation. Current treatment guidelines do not recommend the immediate initiation of HAART unless warranted, potentially allowing long-term, unchecked viral impact on the development of atherosclerosis. Finally, we consider the protease inhibitors traditionally included in HAART regimens and their relationship to the development of dyslipidemia, as well as other classes of antiretrovirals, such as the non-nucleoside reverse transcriptase inhibitors, which might be a better choice for patients with cardiovascular risks. Other strategies, such as pharmacologic, nutritional, and physical activity interventions are discussed. The patients who might benefit most are those in whom the precursors of vascular plaques, such as fatty streak, smooth muscle cell, macrophage, and T-lymphocyte aggregation not yet identified by echocardiographic and biopsy findings have already developed as a result of unchecked viral inflammation and replication.