Aging is characterized by a profound reduction in anti-inflammatory lipoxin A4 levels.

Ongoing low-grade chronic inflammation represents a pathogenetic background for age-related diseases. In this report, we tested the hypothesis that endogenous anti-inflammatory mechanisms may become less efficient with age, resulting in increased susceptibility to inflammatory disorders. Using previously validated ELISA assays, we evaluated urinary levels of the anti-inflammatory, pro-resolution, arachidonic acid (AA) metabolite, lipoxin (LX)A(4) and of the pro-inflammatory cysteinyl leukotrienes (cysLTs) in volunteers aged from 26 to over 100 years. (i) LXA(4) excretion was decreased in elderly people, resulting in a profound unbalance of the LXA(4)/cysLTs ratio, which may be considered an index of the endogenous anti-inflammatory potential. A significant inverse correlation was denoted between age and the LXA(4)/cysLTs ratio (rho = -0.41, P = 0.0026). We conclude that aging is associated with a switch in arachidonic acid metabolism that prevents formation of key 'stop signals' of the inflammatory reaction. This may contribute to promote the development of disease in elderly.

Determinants of platelet activation in hypertensives with microalbuminuria.

Microalbuminuria is a predictor of adverse outcome in hypertension.We evaluated in vivo platelet activation, by urinary 11-dehydrothromboxane (TX)B2 and plasma P-selectin, in hypertensives with or without microalbuminuria, and its possible association with oxidative stress, by urinary 8-iso-prostaglandin (PG)F2alpha and endothelial dysfunction. Sixty essential hypertensive patients, with (n=30) or without (n=30) microalbuminuria, and 30 controls were studied. Endothelial function was assessed by nitric oxide products, intercellular adhesion molecule (ICAM)-1, and asymmetric dimethylarginine (ADMA) levels. Urinary 11-dehydro-TXB2 excretion was higher in microalbuminuric (median 805 pg/mg creatinine) compared to nonmicroalbuminuric patients or controls (414 and 291 pg/mg, respectively; P<0.0001). Plasma P-selectinwas significantly higher in patients with microalbuminuria (median 136 ng/ml) as compared to those without microalbuminuria or controls (85 and 65 ng/ml; P<0.0001). Urinary 8-iso-PGF2alpha excretion was also enhanced in microalbuminuric (median 279 pg/mg creatinine) compared to nonmicroalbuminuric patients or controls (157 and 146 pg/mg, respectively; P<0.0001). A significant impairment in endothelial function was found in microalbuminuric patients, with decreased nitric oxide and increased ICAM-1 and ADMA levels. Multivariate regression analysis showed that urinary 8-iso-PGF2alpha excretion (beta=0.49; P<0.0001) and microalbuminuria (beta=0.36; P<0.001) were independently related to 11-dehydro-TXB2 in hypertensives. Vitamin E supplementation (900 mg daily for 1 month) in 10 hypertensives with microalbuminuria was associated with normalization in median 11-dehydro-TXB2 and 8-iso-PGF2alpha. We conclude that lipid peroxidation is a major determinant of persistent platelet activation in hypertensive patients with microalbuminuria.

Determinants of platelet activation in Alzheimer's disease.

OBJECTIVES: To investigate the rate of platelet thromboxane (TX) biosynthesis and its determinants in Alzheimer's disease. METHODS AND RESULTS: A cross-sectional comparison of urinary 11-dehydro-TXB(2) and 8-iso-prostaglandin (PG)F(2alpha) (markers of in vivo platelet activation and lipid peroxidation, respectively), plasma Vitamin E, C-reactive protein (CRP), tumor necrosis factor (TNF)-alpha and interleukin (IL)-6, was carried-out in 44 Alzheimer patients and 44 matched controls. To investigate the cyclooxygenase (COX)-isoform involved in TXA(2) biosynthesis, nine Alzheimer patients were treated with low-dose aspirin (100mg/d) or rofecoxib (25mg/d) for 4 days. Urinary 11-dehydro-TXB(2) and 8-iso-PGF(2alpha) were significantly higher in Alzheimer patients than in controls (Median: 1983.5 versus 517.5pg/mg creatinine and 938.5 versus 304.0pg/mg creatinine, p<0.0001, respectively), with a significant correlation between the two metabolites (rho=0.75, p<0.0001). An inverse correlation was observed between Vitamin E and both urinary metabolites (8-iso-PGF(2alpha): R(s)=-0.51, p=0.0004; 11-dehydro-TXB(2): R(s)=-0.44, p=0.0026) in Alzheimer patients. No difference was found in CRP, TNF-alpha and IL-6 levels between the two groups. Urinary 11-dehydro-TXB(2) was significantly reduced by aspirin, but not by rofecoxib, consistently with a COX-1-mediated TXA(2) biosynthesis. 8-iso-PGF(2alpha) excretion was not modified by either COX-inhibitor, consistently with its oxygen radical-catalyzed formation. CONCLUSIONS: Platelet activation is persistently enhanced in Alzheimer's disease. This is related, at least in part, to increased lipid peroxidation associated with inadequate levels of Vitamin E.