Combined treatment with DPP-4 inhibitor linagliptin and SGLT2 inhibitor empagliflozin attenuates neointima formation after vascular injury in diabetic mice

Incretin therapy has emerged as one of the most popular medications for type 2 diabetes. We have previously reported that the dipeptidyl peptidase-4 (DPP-4) inhibitor linagliptin attenuates neointima formation after vascular injury in non-diabetic mice. In the present study, we examined whether combined treatment with linagliptin and the sodium glucose cotransporter 2 (SGLT2) inhibitor empagliflozin attenuates neointima formation in diabetic mice after vascular injury. Diabetic db/db mice were treated with 3 mg/kg/day linagliptin and/or 30 mg/kg/day empagliflozin from 5 to 10 weeks of age. Body weight was significantly decreased by empagliflozin and the combined treatment. Blood glucose levels and glucose tolerance test results were significantly improved by empagliflozin and the combined treatment, but not by linagliptin. An insulin tolerance test suggested that linagliptin and empagliflozin did not improve insulin sensitivity. In a model of guidewire-induced femoral artery injury in diabetic mice, neointima formation was significantly decreased in mice subjected to combined treatment. In an in vitro assay using rat aortic smooth muscle cells (RASMC), 100, 500, or 1000 nM empagliflozin significantly decreased the RASMC number in a dose-dependent manner. A further significant reduction in RASMC proliferation was observed after combined treatment with 10 nM linagliptin and 100 nM empagliflozin. These data suggest that combined treatment with the DPP-4 inhibitor linagliptin and SGLT2 inhibitor empagliflozin attenuates neointima formation after vascular injury in diabetic mice in vivo and smooth muscle cell proliferation in vitro.     

Mouse macrophage specific knockout of SIRT1 influences macrophage polarization and promotes angiotensin Ⅱ-induced abdominal aortic aneurysm formation

Abdominal aortic aneurysm (AAA) is a vascular degenerative disease. Macrophage polarization and the balance between classically activated macrophages (M1) and alternatively activated macrophages (M2) are crucial for AAA pathogenesis. The present study aims to investigate the roles of macrophage SIRT1 in AAA formation and macrophage polarization. We found that in mouse peritoneal macrophages, SIRT1 expression was decreased after M1 stimulation, but was enhanced after M2 stimulation. Results from SIRT1^flox/flox mice and macrophage specific SIRT1 knockout mice with treatment of angiotensin II (Ang II) for 4 weeks showed that macrophage specific deficiency of SIRT1 increased the incidence of AAA and exacerbated the severity, including more severe aneurysm types, enlarged diameter of the aneurysm and increased degradation of elastin. In mouse aortas, SIRT1 deficiency increased the pro-inflammatory M1 molecule inducible nitric oxide synthase (iNOS), and decreased M2 molecules such as arginase 1 (Arg1) and mannose receptor (MR). Furthermore, in peritoneal macrophages, SIRT1 deficiency increased the expression of M1 inflammatory molecules, but decreased the expression of M2 molecules. Overexpression of SIRT1 had the opposite effects. Thus, macrophage specific knockout of SIRT1 influences macrophage polarization and accelerates Ang II-induced AAA formation.     

Angiotensin II modulates interleukin-1β-induced inflammatory gene expression in vascular smooth muscle cells via interfering with ERK-NF-κB crosstalk

Angiotensin II is implicated in cardiovascular diseases, which is associated with a role in increasing vascular inflammation. The present study investigated how angiotensin II modulates vascular inflammatory signaling and expression of inducible nitric oxide synthase (iNOS) and vascular cell adhesion molecule (VCAM)-1. In cultured rat aortic vascular smooth muscle cells (VSMCs), angiotensin II suppressed interleukin-1β-induced prolonged phosphorylation of extracellular signal-regulated kinase (ERK) and ribosomal S6 kinase (RSK)-1, and nuclear translocation of nuclear factor (NF)-κB, leading to decreased iNOS but enhanced VCAM-1 expression, associated with an up-regulation of mitogen-activated protein kinase phosphatase-1 expression. Knock-down of RSK1 selectively down regulated interleukin-1β-induced iNOS expression without influencing VCAM-1 expression. In vivo experiments showed that interleukin-1β, iNOS, and VCAM-1 expression were detectable in the aortic arches of both wild-type and apolipoprotein E-deficient (ApoE^−/−) mice. VCAM-1 and iNOS expression were higher in ApoE^−/− than in wild type mouse aortic arches. Angiotensin II infusion (3.2 mg/kg/day, for 6 days, via subcutaneous osmotic pump) in ApoE^−/− mice enhanced endothelial and adventitial VCAM-1 and iNOS expression, but reduced medial smooth muscle iNOS expression associated with reduced phosphorylation of ERK and RSK-1. These results indicate that angiotensin II can differentially modulate inflammatory gene expression in aortic smooth muscle cells through influencing ERK-NF-κB crosstalk, which may contribute to angiotensin II-induced inflammatory disorders related to cardiovascular diseases.     

Regulatory role of vitamins E and C on extracellular matrix components of the vascular system

The protective effect of vitamins E (alpha-tocopherol) and C (L-ascorbic acid) in the prevention of cardiovascular disease (CVD) has been shown in a number of situations but a secure correlation is not universally accepted. Under certain conditions, both, L-ascorbic acid and alpha-tocopherol can exhibit antioxidant properties and thus may reduce the formation of oxidized small molecules, proteins and lipids, which are a possible cause of cellular de-regulation. However, non-antioxidant effects have also been suggested to play a role in the prevention of atherosclerosis. Vitamin E and C can modulate signal transduction and gene expression and thus affect many cellular reactions such as the proliferation of smooth muscle cells, the expression of cell adhesion and extracellular matrix molecules, the production of O(2)(-) by NADPH-oxidase, the aggregation of platelets and the inflammatory response. Vitamins E and C may modulate the extracellular matrix environment by affecting VSMC differentiation and the expression of connective tissue proteins involved in vascular remodeling as well as the maintenance of vascular wall integrity. This review summarizes individually the molecular activities of vitamins E and C on the cells within the connective tissue of the vasculature, which are centrally involved in the maintenance of an intact vascular wall as well as in the repair of atherosclerotic lesions during disease development.     

Exposure to modeled microgravity induces metabolic idleness in malignant human MCF-7 and normal murine VSMC cells

We investigated the effect of modeled microgravity (MMG) on normal vascular smooth muscle cells (VSMC) and neoplastic human breast cancer cells (MCF-7). In both cell types, MMG induced partial arrest in G2M and increased p14-3-3, HSP70, HSP60 and p21 expression. Cells synchronized by 24h starvation reentered the normal cycle within 24h if released in complete medium and exposed to normal gravity, but not if exposed to MMG. Similarly, MMG prevented VSMC and MCF-7 cells from overcoming growth arrest and re-synthesizing DNA. This study shows that cells adjust their metabolic rate in response to MMG.     

Mice carrying a R142C Notch 3 knock-in mutation do not develop a CADASIL-like phenotype

CADASIL (Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy, MIM 125310) is a genetic vascular dementia disease that is linked to missense mutations, small in-frame deletions, and splice site mutations in the human Notch 3 gene. Here we describe the generation of a mouse knockin model for one of the most prevalent CADASIL mutations, an arginine to cysteine transition at position 141, R141C, which corresponds to mutation R142C in mouse NOTCH 3. CADASIL(R142C) mice show no apparent CADASIL-like phenotype after histological and MRI analysis. The NOTCH 3 (R142C) receptor is processed normally and does not appear to accumulate the ectodomain, which has been observed in CADASIL patients. We discuss possible reasons for the different outcomes of the same germline CADASIL mutation in mice and humans.     

非甾体抗炎药抑制大鼠血管平滑肌细胞增殖

本文研究了aspirin、ibuprofen和sulindac三种不同结构的非甾体抗炎药(NSAID)对大鼠A10血管平滑肌细胞(VSMC)增殖的影响并探讨其作用机制。方法:细胞计数法观察不同浓度的三种NSAID对细胞增殖的影响,乳酸脱氢酶(LDH)释放分析法测定NSAID的细胞毒作用,流式细胞术分析测定细胞周期。结果:aspirin、ibuprofen和sulindac三种NSAID都对A10 VSMC的增殖有明显抑制作用,且其作用是浓度依赖性的,IC_(50)分别是:aspirin为1666μmol/L,ibuprofen为937μmol/L,sulindac为520μmol/L;其抑制作用不是因细胞毒作用引起;三种NSAID对细胞周期的作用不同,ibuprofen(1000μmol/L)和sulindac(750μmol/L)将细胞阻抑在细胞周期的G_1期(从68.7±2.0%上升到76.6±2.2%和75.8±2.2%,P<0.05),而aspirin(2500μmol/L)对处于细胞周期各期的细胞百分率无明显改变;利用有丝分裂抑制剂nocodazole辅助分析,更清楚地检测到了ibuprofen和sulindac在G_1阻抑,而aspirin仍然不引起处于细胞周期各期的细胞百分率的明显改变。结论:aspirin抗A10 VSMC的增殖作用机制与ibuprofen和sulindac两者的作用机制不同,本研究为三种NSAID成为VSMC增殖性疾病的治疗药物提供了理论依据。