Blocking of interleukin-1 suppresses angiotensin II-induced renal injury.

Clinical hypertension (HT) is associated with renal inflammation and elevated circulating levels of proinflammatory cytokines. Interleukin (IL)-1 receptor antagonist (IL-1Ra) is one of the most important anti-inflammatory cytokines and plays a crucial role in inflammation. Inhibition of IL-1 may contribute to modulation of the Angiotensin II (Ang II)-induced HT response. The present study aimed to elucidate the effects of IL-1Ra and anti-IL-1ß antibody (01BSUR) on Ang II-induced renal injury. To determine the contribution of IL-1Ra to Ang II-induced renal inflammation, male wildtype (WT) and IL-1Ra-deficient (IL-1Ra-/-) mice were infused with Ang II (1000 ng/kg/min) using subcutaneous osmotic pump for 14 days. We checked renal function, histological change, and several mRNA expressions 14 days after infusion. Fourteen days after infusion, systolic blood pressure (197 ± 5 vs 169 ± 9 mmHg, P<0.05) in IL-1Ra-/- mice significantly increased compared with WT mice. Furthermore, on day 14 of Ang II infusion, plasma IL-6 was 5.9-fold higher in IL-1Ra-/- versus WT mice (P<0.001); renal preproendothelin-1 mRNA expression was also significantly higher in IL-1Ra-/- mice (P<0.05). In addition, renal histology revealed greater damage in IL-1Ra-/- mice compared with WT mice 14 days after infusion. Finally, we administrated 01BSUR to both IL-1Ra-/- and WT mice, and 01BSUR treatment decreased Ang II-induced HT and renal damage (glomerular injury and fibrosis of the tubulointerstitial area) in both IL-1Ra-/- and WT mice compared with IgG2a treatment. Inhibition of IL-1 decreased Ang II-induced HT and renal damage in both IL-1Ra-/- and WT mice, suggesting suppression of IL-1 may provide an additional strategy to protect against renal damage in hypertensive patients.

Omega 3 Polyunsaturated Fatty Acids Suppress the Development of Aortic Aneurysms Through the Inhibition of Macrophage-Mediated Inflammation.

BACKGROUND: Dietary intake of ω3 polyunsaturated fatty acids (ω3-PUFAs) reduces progression of atherosclerosis and prevents future cardiovascular events. Macrophages are key players in the pathogenesis of aortic aneurysm. The effects of ω3-PUFAs on abdominal aortic aneurysm (AAA) formation and macrophage-mediated inflammation remain unclear. METHODS AND RESULTS: The AAA model was developed by angiotensin II infusion in apolipoprotein E-deficient mice. Mice were supplemented with eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA). The development of AAA lesions and macrophage infiltration in the aorta were analyzed. Gene expression of inflammatory markers in aortic tissues and peritoneal macrophages were measured by using quantitative polymerase chain reaction. AAA formation and macrophage infiltration were significantly suppressed after EPA and DHA administration. EPA administration and DHA administration significantly decreased the expression of tumor necrosis factor-α, monocyte chemoattractant protein-1, transforming growth factor-ß, matrix metalloproteinases (MMP)-2, MMP-9, and vascular cell adhesion molecule-1 in the aortas. The expression of arginase 2, which is a marker of pro-inflammatory macrophages, was significantly lower and that of Ym1, which is a marker of anti-inflammatory macrophages, and was significantly higher after EPA and DHA administration. The same trends were observed in peritoneal macrophages after EPA and DHA administration. CONCLUSIONS: Dietary intake of EPA and DHA prevented AAA development through the inhibition of aortic and macrophage-mediated inflammation.

Low-dose oral cyclophosphamide therapy reduces atherosclerosis progression by decreasing inflammatory cells in a murine model of atherosclerosis.

BACKGROUND: Atherosclerosis is a chronic inflammatory disease responsible for most cases of heart disease and stroke in Western countries. The cytotoxic drug cyclophosphamide (CPA) can modulate immune functions, and it has therefore been used to treat patients with autoimmune diseases. Extension of survival of patients with severe atherosclerosis has been reported after CPA treatment, but the underlying mechanism is still poorly understood. METHODS AND RESULTS: We have investigated the effects of CPA in a murine model of atherosclerosis. Continuous oral administration of low-dose CPA (20 mg/kg/day) prevented atherosclerosis in apolipoprotein E-deficient (apoE-/-) mice fed with a high fat diet. After 12 weeks, CPA treatment delayed progression of atherosclerosis in the mice (9.92% vs 3.32%, P < 0.05, n = 7) and reduced the macrophage content of plaques (1.228 vs 0.2975 mm2, P < 0.001). Flow cytometry (FACS) showed that, in peripheral blood and spleen cells, the numbers of B cells and inflammatory T cells (Th1 cells) decreased, and inflammatory monocytes also decreased. However, there were no differences in the bone marrow cells between the two groups. The mRNA levels in the aorta showed significantly decreased inflammatory cytokine (interleukin-6) (P < 0.05), and tended to increase anti-inflammatory cytokine (argininase-1), but no significant differences between the two groups. High dose CPA has cardiotoxicity, but the dose used in this study did not show significant cardiotoxicity. CONCLUSIONS: The results demonstrate that oral treatment with CPA inhibits initiation and progression of atherosclerosis in the apoE-/- mouse model through immunomodulatory effects on lymphoid and inflammatory cells.

Voluntary exercise and cardiac remodeling in a myocardial infarction model.

We investigated the effects of voluntary exercise after myocardial infarction (MI) on cardiac function, remodeling, and inflammation. Male C57BL/6J mice were divided into the following four groups: sedentary + sham (Sed-Sh), sedentary + MI (Sed-MI), exercise + sham (Ex-Sh), and exercise + MI (Ex-MI). MI induction was performed by ligation of the left coronary artery. Exercise consisting of voluntary wheel running started after the operation and continued for 4 weeks. The Ex-MI mice had significantly increased cardiac function compared with the Sed-MI mice. The Ex-MI mice showed significantly reduced expression levels of tumor necrosis factor-α, interleukin (IL)-1ß, IL-6, and IL-10 in the infarcted area of the left ventricle compared with the Sed-MI mice. In the Ex-MI mice, the expression levels of fibrosis-related genes including collagen I and III were decreased compared to the Sed-MI mice, and the expression levels of IL-1ß, IL-6, follistatin-like 1, fibroblast growth factor 21, and mitochondrial function-related genes were significantly elevated in skeletal muscle compared with the Sed mice. The plasma levels of IL-6 were also significantly elevated in the Ex-MI group compared with the Sed-MI groups. These findings suggest that voluntary exercise after MI may improve in cardiac remodeling associated with anti-inflammatory effects in the myocardium and myokine production in the skeletal muscles.

Inhibition of interleukin-1 suppresses angiotensin II-induced aortic inflammation and aneurysm formation.

BACKGROUND: Angiotensin II (Ang II) activates components of the inflammatory cascade, which promotes hypertension and development of abdominal aortic aneurysm (AAA). This study aimed to elucidate the effects of an IL-1 receptor antagonist (IL-1Ra) and an anti-IL-1ß antibody (01BSUR) on Ang II-induced AAA. METHODS AND RESULTS: Male wild-type (WT) and IL-1Ra-deficient (IL-1Ra-/-) mice were infused with Ang II (1000 ng/kg/min) using subcutaneous osmotic pumps for 28 days. Fourteen days post-infusion, both systolic blood pressure (SBP) (Ang II-treated IL-1Ra-/-:149 ±â€¯2 vs. Ang II-treated WT:126 ±â€¯3 mm Hg, p < 0.001) and abdominal aortic width (0.94 ±â€¯0.09 vs. 0.49 ±â€¯0.03 mm, p < 0.001) were significantly higher in IL-1Ra-/- mice than in WT mice. Because 28-day infusion with Ang II in IL-1Ra-/- mice significantly increased the occurrence of fatal aortic rupture (89% vs. 6%, p < 0.0001), both types of mice were infused with Ang II for only 14 days, and histological analyses were performed at 28 days. Interestingly, AAA increased more significantly in IL-1Ra-/- mice than in WT mice (p < 0.001), although SBP did not differ at 28 days in IL-1Ra-/- and WT mice (117 ±â€¯4 vs. 115 ±â€¯3 mm Hg, p = 0.71 (after cessation of Ang II infusion)). Histological analyses showed numerous inflammatory cells around the abdominal aorta in IL-1Ra-/- mice, but not in WT mice. Finally, compared with IgG2a treatment, treatment with 01BSUR decreased Ang II-induced AAA in IL-1Ra-/- mice. CONCLUSIONS: The present study demonstrates that inhibition of IL-1ß significantly suppresses AAA formation after Ang II infusion, suggesting that suppression of IL-1ß may provide an additional strategy to protect against AAA in hypertensive patients.

Possible Role of NADPH Oxidase 4 in Angiotensin II-Induced Muscle Wasting in Mice.

Background: Muscle wasting is a debilitating phenotype associated with chronic heart failure (CHF). We have previously demonstrated that angiotensin II (AII) directly induces muscle wasting in mice through the activation of NADPH oxidase (Nox). In this study, we tested the hypothesis that deficiency of NADPH oxidase 4 (Nox4), a major source of oxidative stress, ameliorates AII-induced muscle wasting through the regulation of redox balance. Methods and Results: Nox4 knockout (KO) and wild-type (WT) mice were used. At baseline, there were no differences in physical characteristics between the WT and KO mice. Saline (vehicle, V) or AII was infused via osmotic minipumps for 4 weeks, after which, the WT + AII mice showed significant increases in Nox activity and NOX4 protein compared with the WT + V mice, as well as decreases in body weight, gastrocnemius muscle weight, and myocyte cross-sectional area. These changes were significantly attenuated in the KO + AII mice (27 ± 1 vs. 31 ± 1 g, 385 ± 3 vs. 438 ± 13 mg, and 1,330 ± 30 vs. 2281 ± 150 µm2, respectively, all P < 0.05). The expression levels of phospho-Akt decreased, whereas those of muscle RING Finger-1 (MuRF-1) and MAFbx/atrogin-1 significantly increased in the WT + AII mice compared with the WT + V mice. Furthermore, nuclear factor erythroid-derived 2-like 2 (Nrf2) and the expression levels of Nrf2-regulated genes significantly decreased in the WT + AII mice compared with the WT + V mice. These changes were significantly attenuated in the KO + AII mice (P < 0.05). Conclusion: Nox4 deficiency attenuated AII-induced muscle wasting, partially through the regulation of Nrf2. The Nox4-Nrf2 axis may play an important role in the development of AII-induced muscle wasting.

An Interleukin-6 Receptor Antibody Suppresses Atherosclerosis in Atherogenic Mice.

IκBNS is a nuclear IκB protein which negatively regulates nuclear factor-κB activity. We demonstrated that IκBNS deficiency accelerates atherosclerosis in LDL receptor-deficient (LDLr-/-) mice via increased interleukin (IL)-6 production by macrophages. Previous studies showed that the increase in IL-6 might contribute to the development of atherosclerotic lesions. However, whether an anti-mouse IL-6 receptor antibody (MR16-1) can protect atherosclerotic lesions in atherogenic mice remains to be elucidated. We investigated atherosclerotic lesions in LDLr-/- and IκBNS-/-/LDLr-/- mice after 16 weeks consumption of a high-fat diet. All mice received intraperitoneal injections of MR16-1 or phosphate-buffered saline (PBS) (control) once a week during a high-fat diet consumption. Treatment of MR16-1 yielded no adverse systemic effects, and we detected no significant differences in serum cholesterol levels in either group. The atherosclerotic lesions were significantly increased in IκBNS-/-/LDLr-/- compared with LDLr-/- mice (p < 0.01) under treatment of PBS. However, MR16-1 treatment abolished the significant difference of atherosclerotic lesions between IκBNS-/-/LDLr-/- and LDLr-/- mice. Interestingly, MR16-1 also significantly decreased atherosclerotic lesions in LDLr-/- mice compared with PBS treatment (p < 0.05). Immunostaining revealed percent phospho-STAT3-positive cell were significantly decreased in the atherosclerotic lesions of MR16-1 treated both IκBNS-/-/LDLr-/- and LDLr-/- mice compared with PBS-treated mice, indicating MR16-1 could suppress atherosclerotic lesions via the inhibition of IL-6-STAT3 signaling pathway. This study highlights the potential therapeutic benefit of anti-IL-6 therapy in preventing atherogenesis induced by dyslipidemia and/or inflammation.