A major pathogenic mechanism of chronic alcoholism involves oxidative burden to liver and other cell types. We show that adult neurogenesis within the dentate gyrus of the hippocampus is selectively impaired in a rat model of alcoholism, and that it can be completely prevented by the antioxidant ebselen. Rats fed for 6 weeks with a liquid diet containing moderate doses of ethanol had a 66.3% decrease in the number of new neurons and a 227-279% increase in cell death in the dentate gyrus as compared with paired controls. Neurogenesis within the olfactory bulb was not affected by alcohol. Our studies indicate that alcohol abuse, even for a short duration, results in the death of newly formed neurons within the adult brain and that the underlying mechanism is related to oxidative or nitrosative stress. Moreover, these findings suggest that the impaired neurogenesis may be a mechanism mediating cognitive deficits observed in alcoholism.A lcohol dependence and abuse are among the most prevalent mental disorders in the United States, with Ϸ14% of the general population meeting criteria for alcohol dependence at some time in their lives and 7% having been dependent in the past year (1). Severe cognitive impairment consistently occurs in chronic alcoholism regardless of the presence of associated thiamine deficits (Korsakoff syndrome), and it includes progressive and severe anterograde learning deficits, implicating impairment in hippocampal circuits. However, no consistent pathological finding has yet been identified. The neuropathological correlate of the cognitive impairments accompanying alcoholism remains unclear (2-4). In animal models of alcoholism, a thinning of the granular layer of the dentate gyrus (DG) is attributed to neuronal loss (5). These findings, however, have been difficult to confirm in human brains (6) and have been contested in animal models as well (7). Human postmortem studies account for the duration of alcohol abuse but not the duration of abstinence before death. Interestingly, MRI studies demonstrate reduction of hippocampal volumes in alcoholics that are reversible after short periods of abstinence (8). The loss of hippocampal volume has been attributed to changes in white matter (6), but the incorporation of newly formed neurons to the DG could also be affected by alcohol. Similarly, hippocampaldependent cognitive functions have also shown reversibility after comparable periods of abstinence.Neurogenesis is primarily a developmental process that involves the proliferation, migration, and differentiation into neurons of primordial CNS stem cells (9, 10). Neurogenesis declines until it ceases in the young adult mammalian brain with two exceptions: the olfactory bulb (OB) and the hippocampus produce new neurons throughout adult life. In the subgranular cell layer of the DG, hippocampal progenitors proliferate and migrate a short distance into the granule cell layer, where they differentiate into hippocampal granule cells. Although multiple factors seem to regulate adult neurogenesis including...

Lipid peroxidation (LPO) is a free radical-related process that in biologic systems may occur under enzymatic control, e.g., for the generation of lipid-derived inflammatory mediators, or nonenzymatically. This latter form is associated mostly with cellular damage as a result of oxidative stress, which also involves cellular antioxidants in this process. This article focuses on the relevance of two LPO products, malondialdehyde (MDA) and 4-hydroxynonenal (HNE), to the pathophysiology of human disease. The former has been studied in human serum samples of hepatitis C virus-infected adults and human immunodeficiency virus-infected children. In these two cases it is shown that the specific assay of serum MDA is useful for the clinical management of these patients. The presence of MDA in subretinal fluid of patients with retinal detachment suggests the involvement of oxidative stress in this process. Moreover, we were able to report the dependence of this involvement on the degree of myopia in these patients. The assay of MDA contents in the peripheral nerves of rats fed a chronic alcohol-containing diet or diabetic mice also confirms the pathophysiologic role of oxidative stress in these experimental models. In these two cases, associated with an increase in tissue LPO products content, we detected a decrease of glutathione peroxidase (GSHPx) activity in peripheral nerve, among other modifications. We have demonstrated that in vitro HNE is able to inhibit GSHPx activity in an apparent competitive manner, and that glutathione may partially protect and/or prevent this inactivation. The accumulation of LPO products in the brain of patients with Alzheimer's disease has also been described, and it is on the basis of this observation that we have tried to elucidate the role of oxidative stress and cellular antioxidants in beta-amyloid-induced apoptotic cell death of rat embryo neurons. Finally, we discuss the possible role of the observed vascular effects of HNE on human arteries.

Lipid peroxidation (LPO) is a free radical-related process that in biologic systems may occur under enzymatic control, e.g., for the generation of lipid-derived inflammatory mediators, or nonenzymatically. This latter form is associated mostly with cellular damage as a result of oxidative stress, which also involves cellular antioxidants in this process. This article focuses on the relevance of two LPO products, malondialdehyde (MDA) and 4-hydroxynonenal (HNE), to the pathophysiology of human disease. The former has been studied in human serum samples of hepatitis C virus-infected adults and human immunodeficiency virus-infected children. In these two cases it is shown that the specific assay of serum MDA is useful for the clinical management of these patients. The presence of MDA in subretinal fluid of patients with retinal detachment suggests the involvement of oxidative stress in this process. Moreover, we were able to report the dependence of this involvement on the degree of myopia in these patients. The assay of MDA contents in the peripheral nerves of rats fed a chronic alcohol-containing diet or diabetic mice also confirms the pathophysiologic role of oxidative stress in these experimental models. In these two cases, associated with an increase in tissue LPO products content, we detected a decrease of glutathione peroxidase (GSHPx) activity in peripheral nerve, among other modifications. We have demonstrated that in vitro HNE is able to inhibit GSHPx activity in an apparent competitive manner, and that glutathione may partially protect and/or prevent this inactivation. The accumulation of LPO products in the brain of patients with Alzheimer's disease has also been described, and it is on the basis of this observation that we have tried to elucidate the role of oxidative stress and cellular antioxidants in ,B-amyloid-induced apoptotic cell death of rat embryo neurons. Finally, we discuss the possible role of the observed vascular effects of HNE on human arteries.

No abstract

Lutein and DHA are capable of normalizing all the diabetes-induced biochemical, histological, and functional modifications. Specifically, the cell death mechanisms involved deserve further studies to allow the proposal as potential adjuvant therapies to help prevent vision loss in diabetic patients.