Apolipoprotein E deficiency and a mouse model of accelerated liver aging.

The liver is the central metabolic organ which regulates several key aspects of lipid metabolism. The liver changes with age leading to an impaired ability to respond to hepatic insults and an increased incidence of liver disease in the elderly. Apolipoprotein E (ApoE) null mice have proved to be a very popular model to study spontaneous atherosclerosis, but recently it has been demonstrated that in ApoE-/- mice liver there are enzymatic and structural alterations, normally linked to the age. The purpose of this study was to consider ApoE-/- mice as a model for oxidative stress induced hepatic disease and to clarify how ApoE inactivation accelerates the aging process and causes liver disease.We used ApoE null mice and control mice at different ages (6 weeks and 15 months).Liver morphological damage as well as proteins involved in oxidative stress and liver ageing were all analyzed.Our study showed that ApoE null mice develop important age-related changes including oxidative stress, pseudocapillarization, increased polyploidy, decreased hepatocyte number and increased nuclear size. Our findings provide evidence that hypercholesterolemic ApoE-/- mice are more likely to develop severe liver injury, suggesting that in addition to vascular disease, increased cholesterol products and oxidative stress may also play a role in accelerating the progression of aging in the liver.

Metabolic syndrome and chronic simvastatin therapy enhanced human cardiomyocyte stress before and after ischemia-reperfusion in cardio-pulmonary bypass patients.

Metabolic syndrome (MetS) is a set of metabolic alterations including high levels of low-density lipoprotein (LDL), which increase the risk of cardiomyopathy often leading to surgery. Despite inducing myopathy, statins are widely used to lower LDL. Cardiopulmonary bypass (Cpb) causes oxidative stress and metabolic injury, altering mitochondrial expression (Grp75) and endoplasmic reticulum (Grp78) chaperones, apoptotic enzymes (Bcl2 family) and increasing cardiomyocyte lipid/lipofuscin storage. We believe that cardiomyocytes from patients with MetS may be more sensitive to surgical stress, in particular after simvastatin therapy (MetS+Stat). The study group included ten patients with MetS, ten patients with Mets+Stat and ten healthy subjects. Myocardial biopsies were obtained both before and after-Cpb. Grp75, Grp78, Bax, Bcl2, lipids, lipofuscin and fibrosis were evaluated by immuno/histochemistry. MetS cardiomyocytes had higher Grp75, Bax, fibrosis and lipofuscin. MetS+Stat had lower Grp75 and higher Grp78 expressions, high Bax, fewer fibrosis and higher lipofuscin content. Cpb did not vary the fibrosis and lipids/lipofuscin content, although it influenced the chaperones and Bax expression in all groups. These changes were more profound in patients with MetS and even more so in patients with MetS+Stat. The results suggest that MetS and MetS+Stat cardiomyocytes were more highly stressed after-Cpb. Interestingly, simvastatin caused high stress even before-Cpb.

Role of apolipoprotein E in renal damage protection.

It is well-known that nephrotic syndrome and chronic renal failure are associated with lipid and lipoprotein abnormalities. For a long time, it has been thought that hyperlipidemia is a secondary and insignificant condition of these renal injuries. Recently, it has been shown that dyslipidaemia may contribute to the development and progression of chronic kidney disease. Apolipoprotein E (apoE) null mice are a very popular model for studying spontaneous hypercholesterolemia, but only limited data are available for the role of apolipoprotein E in kidney disease. The purpose of this study is to evaluate kidney disease in apolipoprotein E deficient mice. For this study, apoE null mice and control mice at different ages (6 weeks and 15 months) were used. Kidney morphological damage and proteins involved in oxidative stress and aging (TNF-α and NF-kB) were analyzed. ApoE deficient mice have morphological alterations that are the hallmark of kidney pathogenesis, which increase with the age of the animals. In apoE null mice kidneys, there is also increased oxidative stress as compared to control mice at the same age and fewer antioxidant enzymes. Our findings add to the growing list of protective effects that apoE possesses.

Beneficial effects of melatonin on nicotine-induced vasculopathy.

Tobacco smoking is responsible for death of many people each year and increases the risk of developing numerous disorders, particularly cardiovascular disease and cancer. Among the components of cigarette smoke, nicotine is known to excert proatherosclerotic, prothrombotic and proangiogenic effects on vascular endothelial cells. The current study was designed to investigate the mechanisms by which nicotine induces endothelial dysfunction and further to examine whether melatonin protects against nicotine-induced vasculopathy. Four groups of male rats (controls, melatonin-treated, nicotine treated [100 microg/mL in drinking water], and nicotine plus melatonin [5 mg/kg/day] treated) were used in this study. After 28 days all the animals were killed by decapitation and the aorta was removed. We evaluated the hydroxyproline content, and the different expression of proteins involved in several types of stress (ERK1/2), in fibrosis (TGF-beta1, NF-kappaB) and in recruitment of circulating leukocytes onto the vessel wall, including intercellular adhesion molecule-1 (ICAM-1) and vascular cellular adhesion molecule-1 (VCAM-1). These metabolic pathways are important in the development of nicotine-induced atherosclerosis and hypertension. Our results show that nicotine induces marked structural and functional alterations in the aorta. Nicotine receptor binding results in activation and phosphorylation of ERK 1/2. This enzyme, in turn, activates both TGF-beta1 and NF-kappaB; they stimulate respectively the synthesis of type I collagen, responsible of fibrosis, and moreover ICAM-1, VCAM-1 and reactive oxygen species. Based on these findings, melatonin is able to minimize the negative effects of nicotine by blocking the activation of ERK and the other signalling pathways in which this enzyme is involved.

Red wine polyphenols prevent cyclosporine-induced nephrotoxicity at the level of the intrinsic apoptotic pathway.

Flavonoids, polyphenol derivatives of plant origin, possess a broad range of pharmacological properties. A number of studies have found both pro/anti-apoptotic effects for many of these compounds. For these reasons we investigated whether Provinols flavonoids obtained from red wine, have anti-apoptotic properties. The investigations have been carried out in rats treated with Cyclosporine A (CsA). In particular, four groups of rats have been treated for 21 days with either olive oil (control group), with CsA, with Provinols, or with CsA and Provinols simultaneously. Oxidative stress, systolic blood pressure, body weight, biochemical parameters and different markers of pro/anti-apoptotic pathway were measured. CsA produced an increase of systolic blood pressure, a decrease in body weight, serum creatinine levels, urinary total protein concentration and creatinine clearance. Moreover, CsA induced renal alterations and the translocation of Bax and cytochrome c from cytoplasm to mitochondria and vice versa. These changes activated the caspase cascade pathway, that leads to morphological and biochemical features of apoptosis. Provinols restored morphological and biochemical alterations and prevented nephrotoxicity. In conclusion, this study may augment our current understanding of the controversial pro-/anti-apoptotic properties of flavonoids and their molecular mechanisms.

The protective effect of caffeic acid phenethyl ester against cyclosporine A-induced cardiotoxicity in rats.

Cyclosporine A (CsA) is the immunosuppressor, which is most frequently used in transplant surgery and in the treatment of autoimmune diseases. Oxidative stress has been considered as one of the possible mechanisms of CsA-induced cardiotoxicity. The present investigation examines the ability of caffeic acid phenethyl ester (CAPE), which is an active component of propolis extracts, as a natural antioxidant to protect against CsA-induced oxidative stress and cardiotoxicity. CsA cardiotoxicity was induced by subcutaneous injection of CsA at a dose of 15 mg/kg/body weight daily for 21 days in rats. Cardiotoxicity was evaluated by morphological and biochemical studies. CsA treated rats showed degenerative changes with cardiac fibrosis localized around the fibers. These latters were disorganised and the network was disappeared. The ROS production was increased whereas cytochrome-c-oxidase decreased. The expression and levels of matrix metalloproteinase 2 (MMP2) were increased whereas those of its inhibitor were downregulated. CAPE subcutaneous administration (15 micromol/kg/day) improved cardiac cytoarchitecture, decreased the levels and the expression of MMP2, and increased those of TIMP2 proteins. Moreover, it increased cytochrome-c-oxidase activity and decreased ROS production. These results suggest that CAPE could have protective effect against CsA-induced cardiotoxicity.