Low-sodium diet induces atherogenesis regardless of lowering blood pressure in hypertensive hyperlipidemic mice.

This study investigated the influence of sodium restriction and antihypertensive drugs on atherogenesis utilizing hypertensive (H) low-density lipoprotein-receptor knockout mice treated or not with losartan (Los) or hydralazine (Hyd) and fed low-sodium (LS) or normal-sodium (NS) chow. Despite reducing the blood pressure (BP) of H-LS mice, the LS diet caused arterial lipid infiltration due to increased plasma total cholesterol (TC) and triglycerides (TG). Los and Hyd reduced the BP of H-LS mice, and Los effectively prevented arterial injury, likely by reducing plasma TG and nonesterified fatty acids. Aortic lipid infiltration was lower in Los-treated H-LS mice (H-LS+Los) than in normotensive (N)-LS and H-LS mice. Aortic angiotensin II type 1 (AT1) receptor content was greater in H-NS than H-LS mice and in H-LS+Hyd than H-LS+Los mice. Carboxymethyl-lysine (CML) and receptor for advanced glycation end products (RAGE) immunostaining was greater in H-LS than H-NS mice. CML and RAGE levels were lower in LS animals treated with antihypertensive drugs, and Hyd enhanced the AT1 receptor level. Hyd also increased the gene expression of F4/80 but not tumor necrosis factor-α, interleukin (IL)-1ß, IL-6, IL-10, intercellular adhesion molecule-1 or cluster of differentiation 66. The novelty of the current study is that in a murine model of simultaneous hypertension and hyperlipidemia, the pleiotropic effect of chronic, severe sodium restriction elicited aortic damage even with reduced BP. These negative effects on the arterial wall were reduced by AT1 receptor antagonism, demonstrating the influence of angiotensin II in atherogenesis induced by a severely LS diet.

Autoantibody profile in the experimental model of scleroderma induced by type V human collagen.

UNLABELLED: The aim of this study is to evaluate the humoral autoimmune response in the experimental model of systemic sclerosis (SSc) induced by human type V collagen (huCol V). New Zealand rabbits were immunized with huCol V in Freund's complete adjuvant (FCA) and boosted twice with 15 days intervals with huCol V in Freund's incomplete adjuvant. Control groups included animals injected only with FCA or bovine serum albumin. Bleeding was done at days 0, 30, 75 and 120. Tissue specimens were obtained for histopathological investigation. Serological analysis included detection of antibodies against huCol V and anti-topoisomerase I (Anti-Scl70) by enzyme-linked immunosorbent assay, antinuclear antibodies (ANA) by indirect immunofluorescence, and rheumatoid factor (RF) by a latex agglutination test. Target antigens were characterized by immunoblot. Histological analysis revealed extracellular matrix remodeling with fibrosis and vasculitis. Anti-Scl70 and ANA were detected as early as 30 days in all huCol V animals. The universal ANA staining pattern was Golgi-like. This serum reactivity was not abolished by previous absorption with huCol V. Characterization of the target antigen by immunoblot revealed two major protein fractions of 175,000 and 220,000 MW. Similarly to ANA, there was a gradual increase of reactivity throughout the immunization and also it was not abolished by preincubation of serum samples with huCol V. RF testing was negative in hyperimmune sera. CONCLUSION: The production of autoantibodies, including anti-Scl70, a serological marker for SSc associated with histopathological alterations, validates huCol V induced-experimental model and brings out its potential for understanding the pathophysiology of SSc.