Effect of age increase on metabolism and toxicity of ethanol in female rats

Alcohol-Drinking Under Limited-Access Procedures During Mature Adulthood Accelerates the Onset of Cognitive Impairment in Mice

A history of heavy drinking increases vulnerability to, and the severity of, Alzheimer’s disease (AD) and related dementias, with alcohol use disorder identified as the strongest modifiable risk factor for early-onset dementia. Heavy drinking has increased markedly in women over the past 10 years, particularly in mature adult women during the coronavirus (COVID-19) pandemic. This is concerning as women are more sensitive to many alcohol-related disease states, including AD and related dementias. Herein, we conducted two studies to determine if a 1-month period of binge drinking during mature adulthood (i.e., 5–9 months of age) impairs spatial and working memory to a greater extent in female vs. male C57BL/6J (B6J) mice. The anxiogenic and cognitive-impairing effects of binge drinking were also compared between mature adult and old B6J mice (18 months of age) in a third study. Throughout, females consumed more alcohol than males, indicating that a sex difference in binge drinking persists into old age. Despite the sex difference in intake, we detected no consistent sex difference in our measures of alcohol withdrawal-induced anxiety during a behavioral test battery. Although mature adult females exhibited more cognitive deficits than males, the precise outcome exhibiting a female-selective effect varied across studies. Old mice drank lower amounts of alcohol than mature adult mice, yet their blood ethanol concentrations (BECs) were within error of the 80 mg/dl criterion for binge drinking, indicative of an age-related slowing of alcohol metabolism. As expected, 18-month-old controls exhibited more signs of cognitive impairment than their 6-month-old counterparts, and binge drinking history impaired the Morris water maze performance of mice of both ages. In contrast, binge drinking history impaired the radial arm maze performance of 6-month-old mice only, and the extent of the impairment was comparable to the behavior exhibited by the older mice. We conclude from our studies that: (1) both biological sex and the age of drinking onset are subject factors that impact voluntary alcohol consumption by mice into old age; (2) binge drinking during later life elicits a negative affective state that is relatively sex-independent; (3) binge drinking during both mature adulthood and old age impairs spatial learning and memory; (4) binge drinking during mature adulthood accelerates deficits in working memory; and (5) mature adult females tend to exhibit more alcohol-induced cognitive impairments than males. If relevant to humans, these findings suggest that binge-like drinking by older adult men and women induces a negative affective state and cognitive decline, but that mature adult women, in particular, may be more sensitive to both the immediate and persistent cognitive-impairing effects of heavy drinking.

The causal web of foetal alcohol spectrum disorders: a review and causal diagram

Foetal alcohol spectrum disorders (FASDs) are a leading cause of developmental disability. Prenatal alcohol use is the sole necessary cause of FASD, but it is not always sufficient. Multiple factors influence a child's susceptibility to FASD following prenatal alcohol exposure. Much of the FASD risk factor literature has been limited to discussions of association, rather than causation. While knowledge of predictor variables is important for identifying who is most at risk of FASD and for targeting interventions, causal knowledge is important for identifying effective mechanisms for prevention and intervention programmes. We conducted a systematic search and narrative synthesis of the evidence and used this to create a causal diagram (directed acyclic graph; DAG) to describe the causal pathways to FASD. Our results show that the aetiology of FASD is multifaceted and complex. FASD risk is determined by a range of lifestyle, sociodemographic, maternal, social, gestational, and genetic factors. The causal diagram that we present in this review provides a comprehensive summary of causal risk factors for FASD and can be used as a tool to inform data collection and statistical modelling strategies to minimise bias in future studies of FASD.

The Role of Apolipoprotein E and Ethanol Exposure in Age-Related Changes in Choline Acetyltransferase and Brain-Derived Neurotrophic Factor Expression in the Mouse Hippocampus

Disruption of apolipoprotein E (APOE) is responsible for age-dependent neurodegeneration and cognitive impairment. Elderly individuals are more sensitive than young individuals to the effects of ethanol (EtOH), particularly those affecting cognition. We investigated the role of APOE deficiency and EtOH exposure on age-dependent alterations in choline acetyltransferase (ChAT) and brain-derived neurotrophic factor (BDNF) mRNA and protein expression in the mouse hippocampus. Three-month-old (young) and 12-month-old (aged) ApoE-knockout (ApoE-KO) and wild-type (WT) mice were treated with saline or 2 g/kg EtOH, and the bilateral hippocampus was collected after 60 min for real-time PCR and western blotting analyses. ChAT (P < 0.01) and BDNF (P < 0.01) expression were significantly decreased in both young and aged saline- and EtOH-treated ApoE-KO mice versus young and aged saline- and EtOH-treated WT mice. Aged saline- and EtOH-treated ApoE-KO mice exhibited greater differences in ChAT and BDNF expression (P < 0.01) than young saline- and EtOH-treated ApoE-KO mice. Aged EtOH-treated WT mice also exhibited larger decreases in BDNF expression (P < 0.01)-but not in ChAT expression-than young EtOH-treated WT mice. EtOH decreased ChAT and BDNF expression in both young (P < 0.01) and aged (P < 0.01) ApoE-KO mice versus EtOH-free ApoE-KO mice of the same age. EtOH also decreased BDNF expression in aged (P < 0.01) WT mice versus EtOH-free aged WT mice. In summary, these results suggest that APOE deficiency and EtOH exposure cause age-dependent decreases in ChAT and BDNF in the hippocampus. Importantly, the decreases in ChAT and BDNF were greater in aged EtOH-treated mice, particularly those lacking APOE, raising the possibility that APOE-deficient individuals who consume alcohol may be at greater risk of memory deficit.

Age-Dependent Susceptibility to Alcohol-Induced Cerebral Artery Constriction

BACKGROUND

Age has been recognized as an important contributor into susceptibility to alcohol-driven pathology.

PURPOSE

We aimed at determining whether alcohol-induced constriction of cerebral arteries was age-dependent.

STUDY DESIGN

We used rat middle cerebral artery (MCA) in vitro diameter monitoring, patch-clamping and fluorescence labeling of myocytes to study an age-dependent increase in the susceptibility to alcohol in 3 (50 g), 8 (250 g), and 15 (440 g) weeks-old rats.

RESULTS

An age-dependent increase in alcohol-induced constriction of MCA could be observed in absence of endothelium, which is paralleled by an age-dependent increase in both protein level of the calcium-/voltage-gated potassium channel of large conductance (BK) accessory β1 subunit and basal BK channel activity. Ethanol-induced BK channel inhibition is increased with age.

CONCLUSIONS

We demonstrate an increased susceptibility of MCA to ethanol-induced constriction in a period equivalent to adolescence and early adulthood when compared to pre-adolescence. Our work suggests that BK β1 constitutes a significant contributor to age-dependent changes in the susceptibility of cerebral arteries to ethanol.

Ethanol-metabolizing activities and isozyme protein contents of alcohol and aldehyde dehydrogenases in human liver: phenotypic traits of the ADH1B*2 and ALDH2*2 variant gene alleles

OBJECTIVE

Alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) are principal enzymes responsible for the metabolism of ethanol. East Asian populations are unique in that they carry both a prevalent ADH1B*2 and a dominant-negative ALDH2*2 allele. A systematic investigation of ethanol-metabolizing activities in normal livers correlated with the corresponding functional allelic variations and protein contents of the relevant isozymes in respective enzyme families has been lacking.

MATERIALS AND METHODS

To obtain a reasonable sample size encompassing all possible genetic allelotypes of the ADH1B and ALDH2, 141 surgical liver specimens from adult Han Chinese were studied. Expression patterns and activities of ADH and ALDH were determined with stratification of the genetic phenotypes. Absolute protein contents as well as cellular localization of the activity and protein of ADH/ALDH isozymes were also investigated.

RESULTS

The activities of ADH1B*1/*2 and ADH1B*2/*2 allelic phenotypes were 5-6-fold those of the ADH1B*1/*1, suggesting that ADH1B*2 allele-encoded subunits are dominant over expression of hepatic ADH activity. The activities of the ALDH2-active phenotype were 90% higher than those of the ALDH2-inactive phenotype. Sex and age did not significantly influence the hepatic ADH and ALDH activities with specified genetic phenotypes. The isozyme protein contents were as follows in decreasing order: ADH1, ADH2, ALDH1A1, ALDH2, and ADH3. Both ADH1, but not ADH2/3, and ALDH1A1/2 showed a preferential expression in perivenular hepatocytes.

CONCLUSION

Functional correlations of ADH1B*2 and ALDH2*2 variant alleles in the liver provide a biochemical genetic basis suggesting their contribution toward variability in ethanol metabolism as well as susceptibility to alcoholism and alcohol-related diseases in East Asians.

Alcohol use across the lifespan: An analysis of adolescent and aged rodents and humans

Adolescence and old age are unique periods of the lifespan characterized by differential sensitivity to the effects of alcohol. Adolescents and the elderly appear to be more vulnerable to many of alcohol's physiological and behavioral effects compared to adults. The current review explores the differential effects of acute alcohol, predominantly in terms of motor function and cognition, in adolescent and aged humans and rodents. Adolescents are less sensitive to the sedative-hypnotic, anxiolytic, and motor-impairing effects of acute alcohol, but research results are less consistent as it relates to alcohol's effects on cognition. Specifically, previous research has shown adolescents to be more, less, and similarly sensitive to alcohol-induced cognitive deficits compared to adults. These equivocal findings suggest that learning acquisition may be differentially affected by ethanol compared to memory, or that ethanol-induced cognitive deficits are task-dependent. Older rodents appear to be particularly vulnerable to the motor- and cognitive-impairing effects of acute alcohol relative to younger adults. Given that alcohol consumption and abuse is prevalent throughout the lifespan, it is important to recognize age-related differences in response to acute and long-term alcohol. Unfortunately, diagnostic measures and treatment options for alcohol dependence are rarely dedicated to adolescent and aging populations. As discussed, although much scientific advancement has been made regarding the differential effects of alcohol between adolescents and adults, research with the aged is underrepresented. Future researchers should be aware that adolescents and the aged are uniquely affected by alcohol and should continue to investigate alcohol's effects at different stages of maturation.

Salivary alcohol dehydrogenase in non-smoking and smoking alcohol-dependent persons

Increasing attention to the importance of saliva testing is not surprising because smoking and alcohol drinking act synergistically on oral tissues, and their metabolite levels, e.g., acetaldehyde, are much higher in saliva than in blood. The activity of salivary alcohol dehydrogenase (ADH) comes from oral microbiota, mucosa, and salivary glands. The purpose of this study was to investigate the involvement of ADH in the oral health pathology of smoking (AS) and non-smoking (ANS) alcohol-dependent males. The results indicated that the AS group had a more significant and longer duration (until the 30th day of alcohol abstinence) decrease in ADH activity and output than the ANS group (until the 15th day of alcohol abstinence) compared to controls (social drinkers; C). The decreased salivary flow (SF) in alcoholics was observed longer in the ANS group (until the 30th day of alcohol abstinence), whereas in the AS group SF normalized at the 15th day, probably due to the irritating effect of tobacco smoke on the oral mucosa. Because saliva was centrifuged to remove cells and debris (including microbial cells), the detected salivary ADH activity was derived from salivary glands and/or oral mucosa. A more profound and longer decrease in ADH activity/output in smoking than non-smoking alcoholics was likely due to the damaged salivary glands and/or oral mucosa, caused by the synergistic effect of alcohol drinking and smoking. The lower values of salivary ADH in smoking than non-smoking alcoholics might also be partly due to the reversed/inhibited ADH reaction by high levels of accumulated acetaldehyde.

Acute alcohol produces ataxia and cognitive impairments in aged animals: a comparison between young adult and aged rats

BACKGROUND

Aging in both humans and rodents appears to be accompanied by physiological changes that increase biologic sensitivity to ethanol (EtOH) intoxication. However, animal models designed to investigate this increased alcohol sensitivity have yet to be established. For this reason, we sought to determine whether acute EtOH administration produces differential effects on motor coordination and spatial cognition in young adult and aged rats.

METHODS

Male young adult (postnatal day 70 to 72) and aged (~18 months) Sprague-Dawley rats were assessed on 2 motor tasks (the accelerating rotarod [RR] and the aerial righting reflex [ARR]) and a single cognitive performance task (the Morris water maze [MWM]). Following acute EtOH exposure via intraperitoneal injection, animals' performance was reassessed.

RESULTS

Aged rats showed a dramatic increase in EtOH-induced ataxia on the RR and the ARR relative to young adult animals. Similarly, results from the MWM revealed that aged animals had slightly greater EtOH-induced impairments compared with young adult animals. Importantly, the increased impairments produced by EtOH were not due to differential blood EtOH levels.

CONCLUSIONS

We demonstrate for the first time that aged rats show greater EtOH-induced deficits compared with young adults in tasks of motor and cognitive performance. The possible role of protein kinase C as a mechanism for increased sensitivity to the motor-impairing effects of EtOH is discussed. Given the high prevalence of alcohol use among the elderly, increased vulnerability to alcohol-induced deficits may have a profound effect on injury in this population.

Aging accentuates alcohol-induced decrease in protein synthesis in gastrocnemius

The present study sought to determine whether the protein catabolic response in skeletal muscle produced by chronic alcohol feeding was exaggerated in aged rats. Adult (3 mo) and aged (18 mo) female F344 rats were fed a nutritionally complete liquid diet containing alcohol (36% of total calories) or an isocaloric isonitrogenous control diet for 20 wk. Muscle (gastrocnemius) protein synthesis, as well as mTOR and proteasome activity did not differ between control-fed adult and aged rats, despite the increased TNF-α and IL-6 mRNA and decreased IGF-I mRNA in muscle of aged rats. Compared with alcohol-fed adult rats, aged rats demonstrated an exaggerated alcohol-induced reduction in lean body mass and protein synthesis (both sarcoplasmic and myofibrillar) in gastrocnemius. Alcohol-fed aged rats had enhanced dephosphorylation of 4E-BP1, as well as enhanced binding of raptor with both mTOR and Deptor, and a decreased binding of raptor with 4E-BP1. Alcohol feeding of both adult and aged rats reduced RagA binding to raptor. The LKB1-AMPK-REDD1 pathway was upregulated in gastrocnemius from alcohol-fed aged rats. These exaggerated alcohol-induced effects in aged rats were associated with a greater decrease in muscle but not circulating IGF-I, but no further increase in inflammatory mediators. In contrast, alcohol did not exaggerate the age-induced increase in atrogin-1 and MuRF1 mRNA or the increased proteasome activity. Our results demonstrate that, compared with adult rats, the gastrocnemius from aged rats is more sensitive to the catabolic effects of alcohol on protein synthesis, but not protein degradation, and this exaggerated response may be AMPK-dependent.

Age- and ethanol concentration-dependent effects of acute binge drinking in the HIV-1 transgenic rat

BACKGROUND

Binge drinking is common in young people. Alcoholic beverages vary significantly in their ethanol (EtOH) concentration (alcohol by volume). We previously showed EtOH concentration-dependent activation of the hypothalamic supraoptic nucleus. In the HIV-infected population, incidence of alcohol abuse is close to 50%. We found age-dependent expression of HIV-1 viral proteins in the HIV-1 transgenic (HIV-1Tg) rat. Thus, we hypothesized that there are age- and EtOH concentration-dependent effects of binge drinking in HIV-1-positive individuals.

METHODS

Blood ethanol concentration was measured in adult F344 rats after gavage (i.g.) administration of water, 20% EtOH, or 52% EtOH. We also compared expression of the HIV-1 viral protein Tat in the brain, spleen, and liver of adult and adolescent HIV-1Tg rats following binge i.g. administration of water, 20% EtOH, or 52% EtOH for 3 days (4.8 g/kg/d) using absolute quantitative real-time reverse transcription-polymerase chain reaction. In a parallel study, we assessed age-dependent motor function in the HIV-1Tg rats 1 day after exposure to 20% EtOH using the open-field test.

RESULTS

Blood ethanol concentration was significantly higher in the 52% EtOH-treated F344 rats compared to the 20% EtOH animals at 90 minutes posttreatment. In the adult HIV-1Tg rats, HIV-1 Tat expression (copies per microgram of total RNA) was significantly increased in the brain, liver, and spleen of the 52% EtOH group, but not in the 20% EtOH group. However, in the adolescent animals, HIV-1 Tat expression in the 52% EtOH group was increased in the brain and liver, but not in the spleen. A significant reduction in locomotor activity occurred in 20% EtOH-treated adult HIV-1Tg rats compared to the water control, although no difference was observed in the adolescent HIV-1Tg animals.

CONCLUSIONS

Our data indicate that binge alcohol drinking can have age- and EtOH concentration-dependent effects in the presence of HIV-1 infection.

Alcohol-induced deterioration in primary antioxidant and glutathione family enzymes reversed by exercise training in the liver of old rats

Chronic alcohol consumption causes severe hepatic oxidative damage, particularly to old subjects by decreasing various antioxidant enzymes. In this study, we test the hypothesis that exercise training can protect the aging liver against alcohol-induced oxidative damage. Two different age groups of Wistar albino rats (3 months young, n=24; 18 months old, n=24) were evenly divided into four groups: control (Con), exercise trained (Tr, 23 m/min 30 min/day, 5 days/week for 2 months), ethanol drinking/treated (Et, 2.0 g/kg b.w. orally), and exercise training plus ethanol drinking/treated (Tr+Et). We found significantly (P<.001) lowered hepatic antioxidant enzymes including superoxide dismutase, catalase, selenium (Se)-dependent glutathione peroxidase (Se-GSH-Px), Se-non-dependent glutathione peroxidase (non-Se-GSH-Px), glutathione reductase, and glutathione S-transferase activities in aged rats compared with young. Age-related decrease in antioxidant enzyme status was further exacerbated with ethanol drinking, which indicates liver in aged rats is more susceptible to oxidative damage because of decreased free radical scavenging system in aged/old ethanol-drinking rats. However, the decrease in liver antioxidant enzymes status with ethanol consumption was ameliorated by 2 months exercise training in old and young rats. These results demonstrate that age-associated decrease in hepatic free radical scavenging system exacerbated by ethanol drinking. For the first time, we found that this deterioration was significantly reversed by exercise training in aging liver, thus protects against alcohol-induced oxidative damage.

Alcohol withdrawal and brain injuries: beyond classical mechanisms

Unmanaged sudden withdrawal from the excessive consumption of alcohol (ethanol) adversely alters neuronal integrity in vulnerable brain regions such as the cerebellum, hippocampus, or cortex. In addition to well known hyperexcitatory neurotransmissions, ethanol withdrawal (EW) provokes the intense generation of reactive oxygen species (ROS) and the activation of stress-responding protein kinases, which are the focus of this review article. EW also inflicts mitochondrial membranes/membrane potential, perturbs redox balance, and suppresses mitochondrial enzymes, all of which impair a fundamental function of mitochondria. Moreover, EW acts as an age-provoking stressor. The vulnerable age to EW stress is not necessarily the oldest age and varies depending upon the target molecule of EW. A major female sex steroid, 17β-estradiol (E2), interferes with the EW-induced alteration of oxidative signaling pathways and thereby protects neurons, mitochondria, and behaviors. The current review attempts to provide integrated information at the levels of oxidative signaling mechanisms by which EW provokes brain injuries and E2 protects against it.

Effects of a preparation of combined glutathione-enriched yeast and rice embryo/soybean extracts on ethanol hangover

The effects of a preparation of combined glutathione-enriched yeast (GEY) and rice embryo/soybean (RES) extracts (20:1), GEY/RES, on experimentally induced ethanol hangover were investigated in male Sprague-Dawley rats. To evaluate the preventive effects on hangover, rats were orally administered GEY/RES (50/2.5, 100/5, or 200/10 mg/kg) for 2 weeks. At 30 minutes after the final treatment, they were challenged with 3 mL/kg ethanol (15 mL of 20% in water/kg). The blood concentrations of alcohol and acetaldehyde were analyzed up to 7 hours postchallenge. Hepatic mRNA expression levels of alcohol-metabolizing enzymes, alcohol dehydrogenase (ADH), cytochrome P450 type 2E1 (CYP2E1), and aldehyde dehydrogenase (ALDH), were determined by real-time polymerase chain reaction. Additional rats were challenged with ethanol and, 60 minutes later, administered GEY/RES to evaluate alcohol clearance. Pretreatment with GEY/RES for 2 weeks reduced the blood concentrations of alcohol and acetaldehyde in a dose-dependent manner, lowering by 29.5% and 54.6% at the highest dose (200/10 mg/kg), respectively. The expressions of mRNAs for ADH and ALDH, the major alcohol-metabolizing enzymes, were markedly increased in the livers of rats administered GEY/RES for 2 weeks, whereas CYP2E1 mRNA was suppressed. Postchallenge treatment with GEY/RES enhanced the alcohol clearance rate by lowering blood concentrations of alcohol and acetaldehyde by 24% and 26.6%, respectively, for the highest dose group. GEY/RES remarkably eliminated 2,2-diphenyl-1-picrylhydrazyl hydrate radical and FeCl(3)-mediated lipid peroxidation in vitro and attenuated hepatic lipid accumulation following ethanol administration in vivo. Therefore, it is suggested that GEY/RES reduces the blood concentrations of alcohol and acetaldehyde not only by modulating alcohol-metabolizing enzymes, but also by exerting its antioxidant activity, and that GEY/RES could be a promising candidate for improvements of alcoholic hangover.

Effect of exercise training on ethanol-induced oxidative damage in aged rats

It is well known that lipid peroxidation increases with age, and alcohol drinking further exacerbates this damage. The present study determined the effect of regular exercise training on alcohol-induced oxidative damage and antioxidant status in the liver of aged animals. The age-matched Wistar albino rats (3 months young, n=24; 18 months old, n=24) were evenly divided into four groups: control (C), exercise trained (Ex), ethanol drinking (Et), and exercise plus ethanol drinking (Ex+Et). With ethanol drinking, hepatic malondialdehyde (MDA) level was significantly elevated above control (P<.001), whereas glutathione (GSH) and ascorbic acid (vitamin C) contents were significantly decreased below control. These changes were found to be greater in the aged rats than those of the young rats. For both age groups, exercise training significantly reversed the increase in MDA and decreases in GSH and ascorbic acid induced by ethanol drinking. The present study showed that ethanol-induced deterioration in lipid peroxidation and reduction in antioxidant status in the liver were exacerbated with age. Here, we found that exercise training significantly reversed the adverse conditions that were caused by ethanol in aged rats.

ADME-tox issues for the elderly

BACKGROUND

The elderly, defined as people aged >65 years, are a heterogeneous population. With increasing age there is increased prevalence of disease for which medication may be indicated and increased drug toxicity.

OBJECTIVE/METHODS

This review of the published scientific and clinical data on absorption, distribution, metabolism, excretion and toxicity (ADME-tox) in old age informs prescribers and drug developers of age-related factors that determine drug dose, safety and efficacy.

RESULTS/CONCLUSION

Increased inter-individual variability is a major feature of toxicology in old age. Changes in ADME-tox associated with normal ageing are currently better described than changes in the frail aged. Reduced hepatic and renal clearance are the most significant toxicokinetic changes seen in normal ageing. Drug toxicity in old age is influenced by changes in the quantity, affinity and responsiveness of drug targets, physiologic reserve and response to injury. Further investigation of the effects of medications on cognitive and physical functions in older adults is required.

Glutathione depletion and recovery after acute ethanol administration in the aging mouse

Glutathione (GSH) plays an important role in the detoxification of ethanol (EtOH) and acute EtOH administration leads to GSH depletion in the liver and other tissues. Aging is also associated with a progressive decline in GSH levels and impairment in GSH biosynthesis in many tissues. Thus, the present study was designed to examine the effects of aging on EtOH-induced depletion and recovery of GSH in different tissues of the C57Bl/6NNIA mouse. EtOH (2-5 g/kg) or saline was administered i.p. to mice of ages 6 months (young), 12 months (mature), and 24 months (old); and GSH and cyst(e)ine concentrations were measured 0-24h thereafter. EtOH administration (5 g/kg) depleted hepatic GSH levels >50% by 6h in all animals. By 24h, levels remained low in both young and old mice, but recovered to baseline levels in mature mice. At 6h, the decrease in hepatic GSH was dose-dependent up to 3g/kg EtOH, but not at higher doses. The extent of depletion at the 3g/kg dose was dependent upon age, with old mice demonstrating significantly lower GSH levels than mature mice (P<0.001). Altogether these results indicate that aging was associated with a greater degree of EtOH and fasting-induced GSH depletion and subsequent impaired recovery in liver. An impaired ability to recover was also observed in young animals. Further studies are required to determine if an inability to recover from GSH depletion by EtOH is associated with enhanced toxicity.

Hepatic glutathione mediated antioxidant system in ethanol treated rats: Decline with age

Alcoholism is a pervasive problem. The aim of the present study was to clarify the effect of ethanol on the hepatic glutathione antioxidant system in young and elderly rats. Male albino Wistar rats of two age groups (3 months and 18 months old) were divided into two experimental groups. The first group of untreated rats served as controls (C; young n=6 and old n=6) and second group received ethanol (Et; young n=6 and old n=6) 2g of ethanol/kg b.w. for 2 months. After the completion of last treatment glutathione (GSH) and antioxidant enzymes glutathione peroxidase (GSH-Px), glutathione reductase (GR) and glutathione-S-transferase (GST) were determined. All these parameters including GST were remarkably decreased in the liver with advancing of age. The ethanol treatment decreased GSH, GSH-Px and GR, whereas, GST was increased in both age groups. The decrease of hepatic antioxidant status with ethanol and aging may be due to over production of free radicals. The changes of parameters studied were greater in the older than in the young rats. In conclusion, ethanol stress exhibited age dependent response on glutathione mediated antioxidant system in the liver.

Cardiac overexpression of alcohol dehydrogenase (ADH) alleviates aging-associated cardiomyocyte contractile dysfunction: role of intracellular Ca2+ cycling proteins

Aging is a complex biological process with contributions from a wide variety of genes including insulin-like growth factor I and alcohol dehydrogenase (ADH), which decline with advanced age. The goal of this study was to examine if ADH enzyme plays any role in cardiac aging. Ventricular myocytes were isolated from young (2-3 months old) or aged (26-28 months old) male FVB wild-type and cardiac-specific ADH (class I, isozyme type 1) transgenic mice. Mechanical properties were measured using an IonOptix system. Aged FVB myocytes displayed significantly reduced ADH activity compared with young ones, which was restored by the ADH transgene. Compared with young cardiomyocytes, aged FVB myocytes exhibited prolonged relengthening duration and a steaper decline in peak shortening amplitude in response to elevated electrical stimuli. Although ADH transgene itself did not alter mechanical properties in young mice, it rescued aging-associated diastolic dysfunction without affecting dampened contractile response to high stimulus frequency. Immunoblot analysis revealed reduced sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA2a) and Na(+)-Ca(2+) exchanger (NCX) levels in conjunction with enhanced phospholamban expression in aged FVB hearts. ADH transgene prevented aging-induced reduction in SERCA2a and NCX without affecting up-regulated phospholamban. Our data suggest that aging is associated with a reduced ADH enzymatic activity and diastolic dysfunction, which may be corrected with cardiac overexpression of the ADH enzyme. Alteration in cardiac Ca(2+) cycling proteins including SERCA2a and NCX may play a role in both pathogenesis of cardiac aging and the beneficial effect of ADH enzyme.

Protective effects of melatonin against ethanol-induced reactive gliosis in hippocampus and cortex of young and aged rats

Evidence has been accumulated indicating that chronic ethanol consumption leads to direct or indirect changes in the viability of central nervous system cells. The effects of aging and chronic ethanol consumption on glial markers [glial fibrillary acidic protein (GFAP) and S100B] and oxidant and antioxidant status of rats were studied. Furthermore, protective effects of melatonin against aging and alcohol consumption were also assayed. Chronic ethanol administration to young and aged rats produced an increase in lipid peroxidation, and a decline in glutathione (GSH) levels, which was significantly reversed by the co-administration of melatonin. Lipid peroxidation status was markedly affected in aged rats treated with alcohol compared to the young rats. An age-related increase in GFAP and S100B levels were found in the cortex and hippocampus. Long-term alcohol exposure resulted in distinct elevation in GFAP content in young rats (P < 0.01) while there was less increase in the cortex of aged rats (P < 0.05). In old rats, hippocampal GFAP levels were not significantly changed by alcohol treatment (P > 0.05). Co-administration of melatonin with alcohol significantly reduced GFAP contents both in the hippocampus (P < 0.01) and cortex (P < 0.001) of aged rats. No significant effects of alcohol treatment were found on the levels of neuron-specific enolase (NSE) in aged rats. This finding suggests that melatonin exerts its protective effect on injured nervous tissues by scavenging free radicals and stabilizing glial activity against the damaging effects of ethanol and aging. Furthermore, this work suggests that the signal to initiate gliosis is mediated, at least indirectly, by free radical formation.