Dietary supplementation with omega-3 polyunsaturated fatty acids modulate matrix metalloproteinase immunoreactivity in a mouse model of pre-abdominal aortic aneurysm.

BACKGROUND: Two-day infusion of angiotensin II to apolipoprotein E-deficient (ApoE(-/-)) mice provides a model of pre-abdominal aortic aneurysm. Long chain omega-3 polyunsaturated fatty acids (n-3 PUFAs) have anti-inflammatory effects. This study examined the effect of an eight-week low or high n-3 PUFA diet in ApoE(-/-) mice on matrix metalloproteinase (MMP) expression and elastin degradation. METHODS: ApoE(-/-) mice were fed a low or high n-3 PUFA diet for eight weeks prior to two-day infusion with angiotensin II. The omega-3 index, MMP-2, MMP-9, TIMP-1, and TGF-ß1 immunoreactivity, and elastin fragmentation were measured. RESULTS: The omega-3 index with the low and high n-3 PUFA diet was 3.78% and 13.03%, respectively. MMP-9 immunoreactive stain intensity was lower in mice fed the high, compared to the low n-3 PUFA diet in endothelial cells (suprarenal aorta), and inflammatory cells (suprarenal and infrarenal aorta). Inflammatory cells had higher TIMP-1 and TGF-ß1 stain intensity in mice fed the high, compared to the low n-3 PUFA diet (suprarenal aorta). MMP-2 immunoreactivity was unaffected by diet. A non-significant trend for reduced elastin fragmentation was observed in mice fed the high n-3 PUFA diet. CONCLUSION: Dietary supplementation with n-3 PUFAs may have protective anti-inflammatory effects mediated through modulation of MMPs and TIMPs.

Aorto-cavitary fistula: a rare case of Enterobacter cloacae infective endocarditis complicated by aortic root abscess and fistula to the right ventricle.

Enterobacter cloacae are a rare cause of infective endocarditis (IE). We present an interesting case of a 51-year-old intravenous drug user with E. cloacae IE of a prosthetic aortic valve and a fistula into the right ventricle. He underwent surgical repair and 6 weeks of intravenous meropenem.

Repair of Less Than Severe Tricuspid Regurgitation During Left-Sided Valve Surgery: A Meta-Analysis.

BACKGROUND: This systematic review and meta-analysis was undertaken to investigate the short- and long-term clinical outcomes of concurrent repair of mild or moderate tricuspid regurgitation (TR) during left-sided valve surgery. METHODS: Medline, PubMed, EMBASE, and Cochrane Libraries were searched, and 12 studies were identified, comprising 1373 patients who underwent TR repair during left-sided valve surgery and 1553 patients who did not. Of these studies, 6 were classified as having a low risk of bias (randomized controlled trials or propensity-matched studies), and 6 were considered as having a high risk of bias (nonmatched observational studies). The primary analysis included only studies with a low risk of bias (399 repair and 426 nonrepair). RESULTS: Primary analysis of studies at low risk of bias demonstrated that the addition of TR repair compared with nonrepair was associated with reduced risks of cardiovascular mortality, all-cause mortality, and progression of TR over a median of 5.3 years of follow-up (cardiovascular mortality: relative risk [RR], 0.46; 95% confidence interval [CI], 0.28 to 0.75; P = .002; all-cause mortality: RR, 0.68; 95% CI, 0.49 to 0.96; P = .03; and TR progression: RR, 0.26; 95% CI, 0.12 to 0.56; P < .001). Cardiopulmonary bypass time was significantly shorter in the nonrepair group (mean weighted difference, 18 minutes; 95% CI, 6 to 30; P = .003), although the risk of perioperative mortality was comparable between the 2 groups (RR, 0.72; 95% CI, 0.27 to 1.97; P > .05). CONCLUSIONS: Concurrent repair of mild or moderate TR during left-sided valve surgery is associated with improved long-term clinical outcomes without adversely affecting early survival. Should these results be validated by ongoing trials, there should be a revision of current guidelines to recommend a more aggressive approach toward TR repair.

Pulmonary vasodilator therapies are of no benefit in pulmonary hypertension due to left heart disease: A meta-analysis.

BACKGROUND: Pulmonary hypertension complicating left heart disease (PH-LHD) is the most common cause of PH. Off-label use of pulmonary arterial hypertension (PAH) medications for PH-LHD is prevalent, despite a lack of clinical data supporting their use. METHODS: A systematic review and meta-analysis was performed. Comprehensive search of all available literature to date identified ten randomised, placebo controlled trials comprising 439 treated (Phosphodiesterase 5 inhibitors: n = 206; guanylate cyclase stimulators: n = 132; endothelin receptor antagonists: n = 101) and 338 placebo patients. Random effects model was employed to assess outcomes in the treatment compared to the placebo control arm. RESULTS: The risks of all-cause mortality, cardiovascular mortality and worsening heart failure were numerically higher in the treated compared to the control group, although not statistically (all-cause mortality: RR = 1.97, 95% CI: 0.64-6.05, p = 0.24; cardiovascular mortality: RR = 2.01, 95% CI: 0.39-10.34, p = 0.4; worsening heart failure: RR = 1.23, 95% CI: 0.68-2.25, p = 0.49). Conversely, right heart hemodynamics improved numerically in the treated group, also without being significant (mean pulmonary artery pressure: MWD = -5.13 mm Hg, 95% CI: -13.2-2.9, p = 0.21; pulmonary vascular resistance: MWD = -0.87 WU, 95% CI: -1.75-0.1, p = 0.053). CONCLUSIONS: The current meta-analysis demonstrated that there is no current evidence to support the widespread use of PAH therapy in PH-LHD. On the basis of a numerically increased risk of clinical harm, these agents should not be prescribed in this setting, unless further evidence of benefit arises in the future.

N-3 PUFAs protect against aortic inflammation and oxidative stress in angiotensin II-infused apolipoprotein E-/- mice.

Abdominal aortic aneurysm is associated with infiltration of inflammatory cells into the aortic wall. The inflammatory response is also evident in animal models, such as apolipoprotein E-deficient (ApoE-/-) mice that have been infused with angiotensin II, prior to development of aortic aneurysm. Since omega-3 polyunsaturated fatty acids (n-3 PUFAs) and their metabolites have anti-inflammatory and pro-resolving activity, we hypothesised that dietary supplementation with n-3 PUFAs would protect against inflammatory processes in this mouse model. Twenty C57 and 20 ApoE-/- 3-4 week old male mice were supplemented with a low (0.14%, n = 10/group) or high (0.70%, n = 10/group) n-3 PUFA diet for 8 weeks before 2-day infusion with 0.9% saline or angiotensin II (1000 ng/kg/min). Four ApoE-/- mice on the low n-3 PUFA diet and none of the ApoE-/- mice on the high n-3 PUFA diet showed morphological evidence of abdominal aortic dissection. The plasma concentration of the n-3 PUFA metabolite, resolvin D1 was higher in angiotensin II-infused ApoE-/- mice fed the high, compared to the low n-3 PUFA diet. The number of neutrophils and macrophages infiltrating the abdominal aorta was elevated in ApoE-/- mice on the low n-3 PUFA diet, and this was significantly attenuated in mice that were fed the high n-3 PUFA diet. Most neutrophils and macrophages were associated with dissected aortas. Immunoreactivity of the catalytic subunit of nicotinamide-adenine dinucleotide phosphate (NADPH) oxidase, Nox2, and superoxide were elevated in ApoE-/- mice that were fed the low n-3 PUFA diet, and this was also significantly attenuated in mice that were fed the high n-3 PUFA diet. Together, the findings indicate that supplementation of ApoE-/- mice with a diet high in n-3 PUFA content protected the mice against pro-inflammatory and oxidative stress responses following short-term infusion with angiotensin II.