High-fat diet- and angiotensin II-induced aneurysm concurrently elicits splenic hypertrophy

Gallic acid ameliorates atherosclerosis and vascular senescence and remodels the microbiome in a sex-dependent manner in ApoE-/- mice

Polyphenols found in fruits and vegetables are associated with a reduced incidence of cardiovascular disease (CVD), the leading cause of death in the USA. Our lab demonstrated that blackberry supplementation reduces atherosclerosis in male, but not in female mice. The current study investigates whether gallic acid (GA), a polyphenol abundant in blackberry, decreases plaque and whether its effect is also sex-dependent. In vitro work using vascular smooth muscle cells (VSMCs) demonstrated that GA reduced cell signaling associated with proliferation, migration, and senescence. ApoE^-/- male and female mice were treated with and without 0.2% GA in drinking water and fed a chow diet (2 weeks), then switched to high-fat diet (HFD) (5 weeks) with the same GA regimen. Similar to the blackberry study, GA reduced atherosclerosis only in males. This GA-induced plaque reduction was independent of plasma cholesterol, triglycerides (TG), LDL, or HDL but corresponded with indices of lower inflammation. Males showed reduced spleen weight and serum IL3 and IL12 levels, and gut health improvement. In females, GA increased anti-atherogenic (HDL and IL10) molecules, while upregulating several pro-inflammatory cytokines and chemokines, including tumor necrosis factor α (TNFα). A major sex-dependent effect of GA was the almost complete disappearance of Eubacterium fissicatena and Turicibacter induced by HFD in males, a finding not seen in females. This study provides novel insights into how GA can improve gut microbiota alterations associated with CVD and suggests that males suffering from atherosclerosis may benefit from GA supplementation, as this polyphenol partially restored microbiome dysbiosis.

Different effects of high-fat and high-sucrose diets on the physiology of perivascular adipose tissues of the thoracic and abdominal aorta

Vascular diseases such as atherosclerosis and aneurysms are associated with diet. Perivascular adipose tissue (PVAT) was reportedly involved in the regulation of vascular functions. It is suggested that imbalanced diets can cause PVAT inflammation and dysfunction as well as impaired vascular function. However, the association between diets and PVAT are not clearly understood. Here, we showed that a high-fat and a high-sucrose diet affected PVAT at different sites. A high-fat diet induced increased number of large-sized lipid droplets and increased CD (Cluster of differentiation) 68+ macrophage- and monocyte chemotactic protein (MCP)-1-positive areas in the abdominal aortic PVAT (aPVAT). In addition, a high-fat diet caused decreased collagen fibre-positive area and increased CD68+ macrophage- and MCP-1-positive areas in the abdominal aorta. In contrast, a high-sucrose diet induced increased number of large-sized lipid droplets, increased CD68+ macrophage- and MCP-1-positive areas, and decreased UCP-1 positive area in the thoracic aortic PVAT (tPVAT). A high-sucrose diet caused decreased collagen fibre-positive area and increased CD68+ macrophage- and MCP-1-positive areas in the thoracic aorta. These results could be attributed to the different adipocyte populations in the tPVAT and aPVAT. Our results provide pathological evidence to improve our understanding of the relationship between diet and vascular diseases.

An association of spleen volume and aortic diameter in patients and in mice with abdominal aortic aneurysm

Background

To investigate the potential mechanism of splenic enlargement in Ang II/APOE model and the associations between the spleen volume and the indices of abdominal aortic aneurysm (AAA) in human.

Methods

To investigate the changes of spleen volume on AAA formation, apolipoprotein E knockout (Apo E^−/−) mice were treated with Ang II (1000 ng/kg/min) up to 28 days to generate AAA. We used Magnetic Resonance Imaging (MRI), liquid measurement, H&E and immunohistochemistry to analyze the morphological or pathological changes of spleen. To investigate the changes of spleen volume in human, a retrospective case-control study involving 30 male AAA patients and 25 male controls were performed. Spleen volume was measured on computed tomography images. Univariate analysis and multivariable sequential logistic regression analyses were used to analyze the association between spleen volume and maximal diameter (Dmax).

Results

In Ang II/APOE model, we found splenic enlargement in mice with AAA compared with the sham group. Histopathological investigations revealed hypertrophies of splenic follicles and increased populations of CD3⁺ T cells. In clinic cohort study, univariate analysis revealed higher values in large AAA (Dmax > 5.5 cm,n = 15) compared with the small (Dmax < 5.5 cm,n = 15) for spleen volume (230.6 ± 64.5 cm³ vs. 170.0 ± 32.8 cm³; P = 0.0030). Regression analysis revealed a statistically significant positive linear correlation of spleen volume and Dmax of AAA (r = 0.3611;P = 0.0423).

Conclusions

Mimicking the splenic pathology observed in murine AAA model, there is a strong positive correlation between spleen volume and the Dmax in male AAA patients. As Dmax is a valuable predictor of AAA rupture, the spleen enlargement may be another indicator.

Attrition of Hepatic Damage Inflicted by Angiotensin II with α-Tocopherol and β-Carotene in Experimental Apolipoprotein E Knock-out Mice

Angiotensin II is one of the key regulatory peptides implicated in the pathogenesis of liver disease. The mechanisms underlying the salubrious role of α-tocopherol and β-carotene on liver pathology have not been comprehensively assessed. Here, we investigated the mechanisms underlying the role of Angiotensin II on hepatic damage and if α-tocopherol and β-carotene supplementation attenuates hepatic damage. Hepatic damage was induced in Apoe(-/-)mice by infusion of Angiotensin II followed by oral administration with α-tocopherol and β-carotene-enriched diet for 60 days. Investigations showed fibrosis, kupffer cell hyperplasia, hepatocyte degeneration and hepatic cell apoptosis; sinusoidal dilatation along with haemorrhages; evidence of fluid accumulation; increased ROS level and increased AST and ALT activities. In addition, tPA and uPA were down-regulated due to 42-fold up-regulation of PAI-1. MMP-2, MMP-9, MMP-12, and M-CSF were down-regulated in Angiotensin II-treated animals. Notably, α-tocopherol and β-carotene treatment controlled ROS, fibrosis, hepatocyte degeneration, kupffer cell hyperplasia, hepatocyte apoptosis, sinusoidal dilatation and fluid accumulation in the liver sinusoids, and liver enzyme levels. In addition, PAI-1, tPA and uPA expressions were markedly controlled by β-carotene treatment. Thus, Angiotensin II markedly influenced hepatic damage possibly by restraining fibrinolytic system. We concluded that α-tocopherol and β-carotene treatment has salubrious role in repairing hepatic pathology.