Wine consumption and renal diseases: new perspectives

Diet and Other Modifiable Factors in Long-Term Decline of Kidney Function: Observational and Population-Based Cohort Study

BACKGROUND

Lower physical activity, lower alcohol intake, higher protein intake, higher sodium intake, and lower potassium intake related to greater kidney function decline over time, according to previous studies. The present study aimed to analyze the cumulative effects of these factors.

METHODS

This prospective, observational, population-based cohort study included 3039 adult examinees of the Gubbio study who participated in the baseline exam and 15-year follow-up exam. Kidney function was evaluated as estimated glomerular filtration rate (eGFR). Habitual physical activity in leisure time and habitual alcohol intake were assessed by questionnaires; dietary intakes of protein, sodium, and potassium were assessed by urinary markers. Based on previous reports, each one of the five modifiable factors was scored 0 for the tertile associated with smaller eGFR decline (low risk), 2 for the tertile associated with greater eGFR decline (high risk), and 1 for the intermediate tertile (intermediate risk). A cumulative score was calculated as the sum of the factor-specific scores and used as the main independent variable.

RESULTS

The cumulative score ranged from 0 to 10, that is, from low risk for all factors to high risk for all factors (skewness = 0.032, mean ± SD = 5 ± 2). To avoid the bias of low-n analyses, score 0 was re-coded as 1 and score 10 was recoded as 9; after re-coding, the cumulative score ranged from 1 to 9 (skewness = 0.016, mean ± SD = 5 ± 2). The cumulative score related to annualized eGFR change in multi-variable linear regression (slope = -0.027, 95%CI = -0.039/-0.014, p < 0.001); findings were consistent in apparently healthy examinees and other subgroups. De novo incidence of eGFR < 60 mL/min × 1.73 m2 was higher along the cumulative score (p < 0.001). Compared to score 1 (n examinees = 35, adjusted incidence = 2.0%), incidence of low kidney function was 4.5 times higher in score 5 (n examinees = 624, adjusted incidence = 8.9%) and 6.5 times higher in score 9 (n examinees = 86, adjusted incidence = 12.9%). The cumulative score related to incidence of low kidney function in multi-variable logistic regression (odds ratio = 1.19, 95%CI = 1.08/1.32, p < 0.001).

CONCLUSIONS

The combination of five modifiable factors predicted large differences in long-term incidence of low kidney function.

Relation of Alcohol Intake to Kidney Function and Mortality Observational, Population-Based, Cohort Study

Data are conflicting about the effects of alcohol intake on kidney function. This population-based study investigated associations of alcohol intake with kidney function and mortality. The study cohort included adult participants in Exam-1, Exam-2 (6-year follow-up), and Exam-3 (20-year follow-up) of the Gubbio study. Kidney function was evaluated as estimated glomerular filtration rate (eGFR, CKD-Epi equation, mL/min × 1.73 m2). Daily habitual alcohol intake was assessed by questionnaires. Wine intake accounted for >94% of total alcohol intake at all exams. Alcohol intake significantly tracked over time (R > 0.66, p < 0.001). Alcohol intake distribution was skewed at all exams (skewness > 2) and was divided into four strata for analyses (g/day = 0, 1−24, 25−48, and >48). Strata of alcohol intake differed substantially for lab markers of alcohol intake (p < 0.001). In multivariable regression, strata of alcohol intake related cross-sectionally to eGFR at all exams (Exam-1: B = 1.70, p < 0.001; Exam-2: B = 1.03, p < 0.001; Exam-3: B = 0.55, p = 0.010) and related longitudinally to less negative eGFR change from Exam-1 to Exam-2 (B = 0.133, p = 0.002) and from Exam-2 to Exam-3 (B = 0.065, p = 0.004). In multivariable Cox models, compared to no intake, intakes > 24 g/day were not associated with different mortality while an intake of 1−24 g/day was associated with lower mortality in the whole cohort (HR = 0.77, p = 0.003) and in the subgroup with eGFR < 60 mL/min × 1.73 m2 (HR = 0.69, p = 0.033). These data indicate a positive independent association of alcohol intake with kidney function not due to a mortality-related selection.

Chemical Composition and Polyphenolic Compounds of Red Wines: Their Antioxidant Activities and Effects on Human Health—A Review

Red wine, an alcoholic beverage is composed of a spectrum of complex compounds such as water, alcohol, glycerol, organic acid, carbohydrates, polyphenols, and minerals as well as volatile compounds. Major factors that affect the levels of phenolic compounds in red wines are the variety of grapes and the storage of the wines. Among the constituents of red wine, phenolic compounds play a crucial role in attributes including color and mouthfeel and confer beneficial properties on health. Most importantly, phenolic compounds such as flavanols, flavonols, flavanones, flavones, tannins, anthocyanins, hydroxycinnamic acids, hydroxybenzoic acids, and resveratrol can prevent the development of cardiovascular diseases, cancers, diabetes, inflammation, and some other chronic diseases.

Short-Chain Alcohols Upregulate GILZ Gene Expression and Attenuate LPS-Induced Septic Immune Response

Alcohol differentially affects human health, depending on the pattern of exposure. Moderate intake provides beneficial mood modulation and an anti-inflammatory effect, while excessive consumption leads to immunosuppression and various alcohol use disorders. The mechanism underlying this bi-phasic action mode of alcohol has not been clearly defined. Our previous publication demonstrated that ethanol, in the absence of glucocorticoids (GCs), induces expression of Glucocorticoid-Induced Leucine Zipper (GILZ), a key molecule that transduces GC anti-inflammatory effect through a non-canonical activation of glucocorticoid receptor (1). Here we report that similar short-chain alcohols, such as ethanol, propanol and isopropanol, share the same property of upregulating GILZ gene expression, and blunt cell inflammatory response in vitro. When mice were exposed to these alcohols, GILZ gene expression in immune cells was augmented in a dose-dependent manner. Monocytes and neutrophils were most affected. The short-chain alcohols suppressed host inflammatory response to lipopolysaccharide (LPS) and significantly reduced LPS-induced mortality. Intriguingly, propanol and isopropanol displayed more potent protection than ethanol at the same dose. Inhibition of ethanol metabolism enhanced the ethanol protective effect, suggesting that it is ethanol, not its derivatives or metabolites, that induces immune suppression. Taken together, short-chain alcohols per se upregulate GILZ gene expression and provide immune protection against LPS toxicity, suggesting a potential measure to counter LPS septic shock in a resource limited situation.

Determination of the Total Phenolic Content in Wine Samples Using Potentiometric Method Based on Permanganate Ion as an Indicator

A rapid and accurate determination method for total phenolic content is of great importance for controlling the quality of wine samples. A promising potentiometric detection approach, based on permanganate ion fluxes across ion-selective electrode membranes, is fabricated for measuring the total phenolic content of wine. The results show that the presence of phenols, such as gallic acid, leads to a potential increase for the potentiometric sensor. Additionally, the present sensor exhibits a linear potential response with the concentration range from 0.05 to 3.0 g/L with a detection limit of 6.6 mg/L calculated using gallic acid. These sensors also exhibit a fast response time, an acceptable reproducibility and long-term stability. These results indicate that the proposed potentiometric sensor can be a promising and reliable tool for the rapid determination of total phenolic content in wine samples.

Effects of active and latent H. pylori infection coupled with chronic alcohol ingestion on cytokine profiles and markers of oxidative balance in men seropositive for H. pylori CagA Ab: An observational study

This study aimed to explore the effects of active and latent Helicobacter pylori infection coupled with alcohol consumption on cytokine profiles and markers of oxidative balance in men seropositive for H. pylori CagA Ab.The 100 male subjects were divided into groups with active H. pylori infection and H. pylori CagA Ab coupled with chronic alcohol ingestion (group A, n = 38), latent H. pylori infection with H. pylori CagA Ab coupled with chronic alcohol ingestion (group B, n = 30), and latent H. pylori infection with H. pylori CagA Ab without chronic alcohol ingestion (group C, n = 32).No differences in serum levels of CRP, IL-10, ADP, E-selectin, MDA, or SOD were detected between the 3 groups or between any 2 groups (all P > .05). The serum IL-6 and TNF-α concentrations in groups A and B were significantly lower than those in group C (P = .004, P = .005, P = .009, and P = .023). However, there were no differences in serum IL-6 and TNF-α between group A and group B (all P > .05).In conclusion, active or latent H. pylori infection coupled with chronic alcohol ingestion may decrease certain cytokines, that is, IL-6 and TNF-α, in men with H. pylori CagA Ab seropositivity. However, there was no difference in the detected cytokine profile between active and latent H. pylori infection coupled with chronic alcohol ingestion, and no changes were detected in markers of oxidative balance in men with H. pylori CagA Ab.

Protective potency of Meristotropis xanthioides against nephrotoxicity in a rat model along with its antioxidant and antibacterial activities

OBJECTIVE

To investigate nephroprotective potential of Meristotropis xanthioides (M. xanthioides) extract against ethanol-induced nephrotoxicity in Wistar rats, and also its total phenolics content, antioxidant and antibacterial activities.

METHODS

Total phenol and flavonoid amounts of the leaf and stem extracts were determined by Folin-Ciocalteu and aluminum chloride reagents, respectively. Antioxidant and antibacterial activities of the extracts were investigated by 2,2-diphenyl-1-picrylhydrazyl radical scavenging and disc diffusion methods, respectively. In addition, protective potential of the leaf extract against ethanol-induced nephrotoxicity was studied by histological and biochemical analyses.

RESULTS

Obtained results indicated high total phenol [(10.26 ± 0.46) mg GAE/g of dry extract] and flavonoid [(3.63 ± 0.62) mg QE/g of dry extract] amounts in the leaf extract. The leaf and stem extracts possessed stronger antioxidant activity [IC₅₀: (0.119 ± 0.006) mg/mL and IC₅₀: (0.133 ± 0.009 mg/mL)] than that of ascorbic acid [IC₅₀: (0.142 ± 0.002) mg/mL]. Also, the extracts showed good antibacterial activity against the most of bacteria taken in this research, especially Gram-positive ones. Histological examinations revealed tissue injury in the kidney of rats treated with ethanol. Results from biochemical assays showed reduction in total protein content and also in superoxide dismutase activity. In addition, remarkable increased levels (P < 0.05) of H₂O₂ and malondialdehyde were found in ethanol-treated rats in comparison to control group. However, these injuries were significantly improved in rats treated by M. xanthioides leaf extract.

CONCLUSIONS

Results from present study demonstrates strong pharmaceutical potential of M. xanthioides extract to apply as a new drug supplement.

Differential roles of 3-Hydroxyflavone and 7-Hydroxyflavone against nicotine-induced oxidative stress in rat renal proximal tubule cells

Plant flavonoids are well known as antioxidants against oxidative stress induced by exposure to external pollutants. Nicotine (NIC) is one of those agents which increases renal oxidative stress, an important factor in the pathogenesis of renal epithelial injury in smokers. Although several studies had been conducted on flavonoids and oxidative stress, the mechanism of the protective pathways are not fully understood. Here, we present studies on antioxidant properties of two mono-hydroxyflavone isomers, 3-hydroxyflanove (3HF)- and 7-hydroxyflavone (7HF), against nicotine-associated oxidative stress and injury in cultured renal proximal tubule cells and correlate their antioxidant properties with their chemical structure. Our data clearly demonstrates, for the first time, that while both 3HF and 7HF protect renal cells from NIC-associated cytotoxicity, the mechanism of their action is different: 3HF elicits protective activity via the PKA/CREB/MnSOD pathway while 7HF does so via the ERK/Nrf2/HO-1 pathway. Molecular docking and dynamics simulations with two major signaling pathway proteins showed significant differences in the binding energies of 3HF (-5.67 and -7.39 kcal.mol-1) compared to 7HF (-5.41 and -8.55 kcal.mol-1) in the matrices of CREB and Keap1-Nrf2 proteins respectively, which corroborate with the observed differences in their protective properties in the renal cells. The implications of this novel explorative study is likely to promote the understanding of the mechanisms of the antioxidative functions of different flavones.

Non-canonical Glucocorticoid Receptor Transactivation of gilz by Alcohol Suppresses Cell Inflammatory Response

Acute alcohol exposure suppresses cell inflammatory response. The underlying mechanism has not been fully defined. Here we report that alcohol was able to activate glucocorticoid receptor (GR) signaling in the absence of glucocorticoids (GCs) and upregulated glucocorticoid-induced leucine zipper (gilz), a prominent GC-responsive gene. Such a non-canonical activation of GR was not blocked by mifepristone, a potent GC competitor. The proximal promoter of gilz, encompassing five GC-responsive elements (GREs), was incorporated and tested in a luciferase reporter system. Deletion and/or mutation of the GREs abrogated the promoter responsiveness to alcohol. Thus, the GR–GRE interaction transduced the alcohol action on gilz. Alcohol induced GR nuclear translocation, which was enhanced by the alcohol dehydrogenase inhibitor fomepizole, suggesting that it was alcohol, not its metabolites, that engendered the effect. Gel mobility shift assay showed that unliganded GR was able to bind GREs and such interaction withstood clinically relevant levels of alcohol. GR knockout via CRISPR/Cas9 gene targeting or GILZ depletion via small RNA interference diminished alcohol suppression of cell inflammatory response to LPS. Thus, a previously unrecognized, non-canonical GR activation of gilz is involved in alcohol modulation of cell immune response.

Simvastatin attenuates angiotensin II‑induced inflammation and oxidative stress in human mesangial cells

Chronic kidney disease (CKD) is an intractable disease in which inflammation and oxidative stress are important. In the present study, the effect of simvastatin on inflammation and oxidative stress induced by angiotensin II (Ang II) in human mesangial cells (HMCs) and its corresponding mechanism was examined. In the in vitro experiment, HMCs were pretreated either without additives (control group) or with simvastatin at different concentrations (0, 0.1, 1 or 10 µM) for 1 h and were then stimulated by Ang II (1 µM) for 24 h. Following stimulation, the cells were collected for analysis using quantitative polymerase chain reaction, western blotting and dihydroethidium staining. The supernatant of the cells was collected and analyzed using an enzyme‑linked immunosorbent assay. The results demonstrated that simvastatin suppressed the increased mRNA expression of monocyte chemoattractant protein‑1, tumor necrosis factor‑α, interleukin (IL)‑1β and IL‑6 and the content of reactive oxygen species induced by Ang II in a dose‑dependent manner. In addition, simvastatin decreased the protein expression of cyclooxygenase‑2 (COX‑2), nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and protein kinase C (PKC) as well as the content of prostaglandin E2 and the phosphorylation level of nuclear factor‑κB (NF‑κB) p65 in a dose‑dependent manner. Furthermore, simvastatin significantly increased the protein expression of peroxisome proliferator‑activated receptor γ (PPARγ). Therefore, simvastatin suppressed inflammation and oxidative stress in Ang II‑stimulated HMCs via COX‑2, PPARγ, NF‑κB, NADPH oxidase and PKCs, thereby exerting a protective effect on CKD.

A retrospective case-control analysis of the outpatient expenditures for western medicine and dental treatment modalities in CKD patients in Taiwan

BACKGROUND

To determine if expenditures for dentistry (DENT) correlate with severity of chronic kidney disease (CKD).

METHODS

A total of 10,457 subjects were enrolled from January 2008 to December 2010, divided into three groups: healthy control (HC) group (n = 1,438), high risk (HR) group (n = 3,392), and CKD group (n = 5,627). Five stages were further categorized for the CKD group. OPD utilization and expenditures for western medicine (WM), DENT, and TCM (traditional Chinese medicine) were analyzed retrospectively (2000-2008) using Taiwan's National Health Insurance Research Database. Three major areas were analyzed among groups CKD, HR and HC in this study: 1) demographic data and medical history; 2) utilization (visits/person/year) and expenditures (9-year cumulative expenditure, expenditure/person/year) for OPD services in WM, DENT, and TCM; and 3) utilization and expenditures for dental OPD services, particularly in dental filling, root canal and periodontal therapy.

RESULTS

OPD utilization and expenditures of WM increased significantly for the CKD group compared with the HR and HC groups, and increased steadily along with the severity of CKD stages. However, overall DENT and TCM utilization and expenditures did not increase for the CKD group. In comparison among different CKD stages, the average expenditures and utilization for DENT including restorative filling and periodontal therapy, but not root canal therapy, showed significant decreases according to severity of CKD stage, indicating less DENT OPD utilization with progression of CKD.

CONCLUSIONS

Patients with advanced CKD used DENT OPD service less frequently. However, the connection between CKD and DENT service utilization requires further study.

Wine, Food and Health

Wine has historically been associated with religious rights, used as a salubrious beverage, employed as a medication as well as a medicinal solvent, and consumed as a food accompaniment. It is the latter that is most intimately associated in the minds of most modern consumers. Despite this, there is little flavor commonality on which pairing could be based. The first section of the chapter examines this feature, and wine’s primary role as a palate cleanser and food condiment. The synergistic role of food and wine in suppressing each other’s least pleasant attributes is also explained. The final section deals with the latest evidence relating to the many beneficial health effects of moderate wine consumption, shortfalls in the data, headache induction, dental erosion, and conditions under which wine intake is contraindicated.

Hepatoprotective, cardioprotective, and renal-protective effects of organic and conventional grapevine leaf extracts on Wistar rat tissues

The purpose of this study was to evaluate the beneficial effects of organic and conventional grapevine (Vitis labrusca L.) leaf extracts in reducing hydrogen peroxide-induced stress in the liver, heart and kidney of Wistar rats by measuring lipids and proteins damages (carbonyl assay), as well as the activity of the antioxidant enzymes superoxide dismutase and catalase. The preincubation with 5 mg/mL of organic and conventional grapevine (Vitis labrusca L.) leaf extracts prevented both lipids and proteins oxidative damages in all tissues analyzed. The organic leaf extract was able to restore superoxide dismutase (kidney and liver) and catalase (heart) activities, which were modified by the treatment with H(2)O(2). The conventional extract was able to restore only the catalase activity in liver and heart tissues. The beneficial effects of the V labrusca leaf extract shown in this study could probably be important for formulating dietary supplements, as well as for developing new ingredients with improved antioxidant properties from other plant sources.

Association of betel nut chewing with chronic kidney disease: a retrospective 7-year study in Taiwan

AIM

Only few studies have reported that betel nut (BN) chewing is independently associated with chronic kidney disease (CKD); however, the sample size was relatively small. This study was to explore further the association between BN chewing and CKD using a larger case series.

METHODS

We retrospectively reviewed the records of a health check-up program from 2003 to 2009. Laboratory tests, medical history and status of cigarette smoking, alcohol drinking and BN chewing were compared between CKD and non-CKD groups. We checked interaction effects between BN chewing and all other covariates, and conducted multivariate logistic regression analysis to explore the risk of CKD with BN chewing.

RESULTS

A total of 27 482 participants (15 491 females and 11 991 males, mean age 58.02 ± 11.85 years) were included in the study, of whom 4519 (16.4%) had CKD and 1608 (5.9%) chewed BN. CKD prevalence in the chewers was higher than in the non-chewers in all age groups per decade. BN chewing was significantly associated with CKD in overall subjects (odds ratio (OR) = 1.23, P = 0.027) and also in the male (OR = 1.23, P = 0.035), non-drinking (OR = 1.62, P = 0.000), non-diabetic (OR = 1.27, P = 0.021), and non-proteinuric groups (OR = 1.30, P = 0.013). This relationship was insignificant in female, drinking, diabetic and proteinuric groups.

CONCLUSION

The association between BN chewing and CKD seemed conditional on demographics, health behaviours, and underlying co-morbidities. This association should be interpreted cautiously.

Alcohol drinking, mean corpuscular volume of erythrocytes, and alcohol metabolic genotypes in drunk drivers

Regular and irregular abuse of alcohol are global health priorities associated with diseases at multiple sites, including cancer. Mechanisms of diseases induced by alcohol are closely related to its metabolism. Among conventional markers of alcohol abuse, the mean corpuscular volume (MCV) of erythrocytes is prognostic of alcohol-related cancer and its predictivity increases when combined with functional polymorphisms of alcohol dehydrogenase (ADH1B [rs1229984] and ADH1C [rs698]) and the mitochondrial aldehyde dehydrogenase (ALDH2 [rs671]). Whether these genetic variants can influence abuse in alcohol drinking and MCV has never been examined in drunk-driving traffic offenders. We examined 149 drunk drivers, diagnosed as alcohol abusers according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth edition Text Revision (DSM-IV-TR) and enrolled in a probation program, and 257 social drinkers (controls), all Caucasian males. Alcohol intake was assessed according to self-reported drink-units/d and MCV unadjusted and adjusted for age, smoking, and body mass index. Multivariable models were used to compute MCV adjusted means. Genotype analyses were performed by PCR on DNA from blood. The adjusted MCV mean was higher in drunk-driving abusers than in controls (92 vs. 91fL; P<.0001) and increased with the number of drink-units/d in both abusers and controls (P-trend=.0316 and .0089) already at intermediate quantities (0-1 vs. 2-4 drink-units/d: P=.054 and .024). Carriers of the common ADH1B*1/*1 (rs1229984) genotype were more likely to be drunk-driving abusers (P=.008), reported higher drink-units/d (P=.0126), and had larger MCV (P=.035). The rs698 ADH1C and rs671 ALDH2 polymorphisms were not associated with MCV. ADH1B*1/*1 polymorphism is significantly associated with being a drunk-driving abuser, higher alcohol drinking, and MCV enlargement. This suggests that drunk drivers with augmented MCV modulated by the alcohol metabolic ADH1B*1/*1 genotype may be at higher risk of driving incapability and of alcohol-related cancer.

Melatonin and vitamin C ameliorate alcohol-induced oxidative stress and eNOS expression in rat kidney

OBJECTIVES

The aim of this study was to investigate the preventive effects of melatonin and vitamin C as antioxidants on renal injury in chronic alcohol consumption.

MATERIALS AND METHODS

A total of 24 adult male Wistar rats weighing 200-250 g were used in the study. Rats were divided into four equal groups. Group I (control): rats were not fed on alcohol; Group II: rats were fed on alcohol; Group III: rats were fed on alcohol and 40 mg/kg vitamin C; and Group IV: rats were fed on alcohol and 4 mg/kg melatonin.

RESULTS

Light microscopic examination revealed atrophic renal corpuscles, dilatation and congestion of the peritubular vessels, and renal corpuscles with obscure Bowman's space and a few foamy-appearing tubules due to alcohol consumption were observed. Expression of endothelial nitric oxide synthase (eNOS) was localized to glomerulus, distal, and collector tubules. eNOS staining decreased in alcohol treatment group and melatonin and vitamin C encore increased expression pattern of eNOS. Alcohol consumption increased malondialdehyde (MDA) level and superoxide dismutase (SOD) and catalase (CAT) activities significantly in the alcohol consumption groups compared with that in the control group, while in melatonin give group just MDA level was decreased statistically significant and SOD and CAT activities were also decreased numerically compared with the alcohol consumption groups.

CONCLUSIONS

These results indicated that chronic alcohol consumption caused renal damage by increased lipid peroxidation and melatonin and vitamin C administration produced in some degree protection against alcohol-induced damage.

Effect of chronic dementia caregiving and major transitions in the caregiving situation on kidney function: a longitudinal study

OBJECTIVE

To estimate the glomerular filtration rate (GFR) in relation to the chronic stress of dementia caregiving and major transitions in the caregiving situation.

METHODS

We longitudinally assessed 119 people serving as caregivers for their spouses with Alzheimer's disease and 58 noncaregiving controls for a period of up to 3 years (mean of 2.8 assessments per participant). At baseline, the mean (standard deviation [SD]) age of all participants was 74.5 (7.5) years. Random regression models with fixed and time-variant effects for psychosocial factors, risk factors of chronic kidney disease, and caregiving transitions were used to evaluate changes over time in estimated GFR.

RESULTS

The change in GFR did not differ between caregivers and controls during follow-up (p = .77). Further analyses revealed that GFR declined disproportionately after placement of the spouse in a nursing home at 3 months after placement (-4.9 [2.2] mL/min per 1.73 m(2); p = .03). Post hoc analyses showed that this effect was stronger in caregivers with hypertension compared with those without hypertension (-5.7 [3.1] versus -2.4 [3.4] mL/min per 1.73 m(2)), as well as in caregivers with diastolic blood pressure (BP) levels at 1 SD above the mean than in those with diastolic BP levels at 1 SD below the mean (-8.3 [2.9] versus -1.4 [2.7] mL/min per 1.73 m(2)).

CONCLUSIONS

Kidney function did not differ between caregivers and controls over time. However, GFR had impaired at 3 months after a major caregiving transition. Because the effect of placement of the spouse with Alzheimer's disease on the decline in GFR was moderated by BP, it might be confined to caregivers who experience increased sympathetic activation after placement.

Preconditioning with physiological levels of ethanol protect kidney against ischemia/reperfusion injury by modulating oxidative stress

Background

Oxidative stress due to excessive production of reactive oxygen species (ROS) and subsequent lipid peroxidation plays a critical role in renal ischemia/reperfusion (IR) injury. The purpose of current study is to demonstrate the effect of antecedent ethanol exposure on IR-induced renal injury by modulation of oxidative stress.

Materials and Methods

Bilateral renal warm IR was induced in male C57BL/6 mice after ethanol or saline administration. Blood ethanol concentration, kidney function, histological damage, inflammatory infiltration, cytokine production, oxidative stress, antioxidant capacity and Aldehyde dehydrogenase (ALDH) enzymatic activity were assessed to evaluate the impact of antecedent ethanol exposure on IR-induced renal injury.

Results

After bilateral kidney ischemia, mice preconditioned with physiological levels of ethanol displayed significantly preserved renal function along with less histological tubular damage as manifested by the reduced inflammatory infiltration and cytokine production. Mechanistic studies revealed that precondition of mice with physiological levels of ethanol 3 h before IR induction enhanced antioxidant capacity characterized by significantly higher superoxidase dismutase (SOD) activities. Our studies further demonstrated that ethanol pretreatment specifically increased ALDH2 activity, which then suppressed lipid peroxidation by promoting the detoxification of Malondialdehyde (MDA) and 4-hydroxynonenal (HNE).

Conclusions

Our results provide first line of evidence indicating that antecedent ethanol exposure can provide protection for kidneys against IR-induced injury by enhancing antioxidant capacity and preventing lipid peroxidation. Therefore, ethanol precondition and ectopic ALDH2 activation could be potential therapeutic approaches to prevent renal IR injury relevant to various clinical conditions.

Renal impairment and moderate alcohol consumption in the elderly. Results from the Italian Longitudinal Study on Aging (ILSA)

OBJECTIVE

The influence of moderate alcohol consumption on renal function is not clear in elderly people. The aim of the present study was to investigate the relationship between alcohol consumption and renal function, expressed as serum creatinine levels and glomerular filtration rates (GFR), in an elderly population.

DESIGN

Perspective cohort study.

SETTING

Population-based study on an elderly Italian population.

SUBJECTS

A sample of 3404 Italian people (1619 women and 1785 men), aged 65-84 years, from the Italian Longitudinal Study on Aging (ILSA).

RESULTS

Prevalence and cumulative risk of impaired renal function (defined as GFR ≤ 60 ml/min) were estimated by sex and alcohol consumption groups. Logistic regression analysis adjusting for confounders (age, education, smoking, BMI and medications) and intermediate factors (blood cholesterol and fibrinogen, systolic hypertension and diabetes) showed that alcohol consumption level was not significantly related to the prevalence of mild renal impairment in elderly women. In men, both prevalence and incidence results seemed to suggest an inverse linear relationship between moderate alcohol consumption and the risk of mild renal impairment. A U-shaped association was shown for women at the incidence phase, suggesting a higher risk of developing renal impairment for women who drink more than 24 g alcohol/d.

CONCLUSIONS

Our results suggest that, in accordance with the recommendations on alcohol consumption in the elderly, moderate quantities of alcohol are not injurious to renal function in elderly men.

Roasted licorice extracts dampen high glucose-induced mesangial hyperplasia and matrix deposition through blocking Akt activation and TGF-beta signaling

Diabetic nephropathy (DN) characterized as nephrotic syndrome and diffuse glomerulosclerosis can cause renal failure and end-stage kidney disease. Expansion of mesangial matrix around capillaries in the kidney glomeruli is a prominent feature of DN. This study investigated whether licorice extracts inhibited mesangial cell (MC) proliferation and matrix accumulation induced by high glucose (HG). Human renal MC were cultured in media containing 5.5 mM glucose plus 27.5 mM mannitol as an osmotic control or 33 mM glucose for 3 d in the presence of water or ethanol extracts from raw licorice (LW, LE) or roasted licorice (RLW, RLE). Non-polar components including glycyrrhetic acid were elevated during licorice roasting, whereas polar components soluble in water extracts were diminished. Exposure of cells to HG caused significant increases in collagen IV secretion and connective tissue growth factor (CTGF) expression, which was appeased by RLW and RLE at transcriptional levels. The inhibitory potency was high in the order of RLE > or = RLW > or = LE > > LW. Non-polar glycyrrhetic acid but not glycyrrhizin retarded HG-stimulated mesangial matrix deposition through diminishing CTGF expression. In addition, RLW and RLE but not LW modulated membrane type matrix metalloproteinase-1 (MT-1 MMP) expression, MMP-2 activity and tissue inhibitor of MMP-2 (TIMP-2), which facilitated the degradation of mesangial matrix. Furthermore, the augmented expression of CTGF and TIMP-2 in HG-exposed cells was mediated by Akt activation and TGF-beta/Smad signaling through PKCbeta2-responsive signaling pathways. However, HG-down-regulated MT-1 MMP expression was independent of activation of ERK1/2 and Akt when using their inhibitors of DB98059 (ERK1/2) and LY294002 (Akt) alone or in combination. These results demonstrate that extracts from roasted licorice may be highly potent therapeutic agents for the prevention and treatment of mesangial fibrosis and glomerulosclerosis leading to diabetes nephropathy due to longstanding diabetes mellitus.

Early exposure to ethanol or red wine and long-lasting effects in aged mice. A study on nerve growth factor, brain-derived neurotrophic factor, hepatocyte growth factor, and vascular endothelial growth factor

Prenatal ethanol exposure produces severe changes in brain, liver, and kidney through mechanisms involving growth factors. These molecules regulate survival, differentiation, maintenance, and connectivity of brain, liver, and kidney cells. Despite the abundant available data on the short and mid-lasting effects of ethanol intoxication, only few data show the long-lasting damage induced by early ethanol administration. The aim of this study was to investigate changes in nerve growth factor (NGF), brain derived neurotrophic factor (BDNF), hepatocyte growth factor (HGF), and vascular endothelial growth factor (VEGF) in brain areas, liver, and kidney of 18-mo-old male mice exposed perinatally to ethanol at 11% vol or to red wine at the same ethanol concentration. The authors found that ethanol per se elevated NGF, BDNF, HGF, and VEGF measured by ELISA in brain limbic system areas. In the liver, early exposure to ethanol solution and red wine depleted BDNF and VEGF concentrations. In the kidney, red wine exposure only decreased VEGF. In conclusion, the present study shows that, in aged mice, early administration of ethanol solution induced long-lasting damage at growth factor levels in frontal cortex, hippocampus, and liver but not in kidney. Otherwise, in mice exposed to red wine, significant changes were observed in the liver and kidney but not in the hippocampus and frontal cortex. The brain differences in ethanol-induced toxicity when ethanol is administered alone or in red wine may be related to compounds with antioxidant properties present in the red wine.

Adherence to the Mediterranean diet is associated with renal function among healthy adults: the ATTICA study

BACKGROUND

No data exist regarding the effect of the Mediterranean diet on renal function. We studied the association between adherence to the Mediterranean diet and markers of renal function among 3042 people without any evidence of chronic disease.

METHODS

During 2001 and 2002, a random sample was selected of 1514 men and 1528 women (aged 18 to 89 years) from Greece. Urea and creatinine were measured, and the creatinine-clearance (CCr) rate was estimated according to the formula of Cockcroft and Gault. Adherence to the Mediterranean diet was assessed using a validated diet score (MedDietScore) that incorporated the inherent characteristics of this diet.

RESULTS

The CCr rate was positively associated with MedDietScore (b+/-SE, 0.24+/-0.09, P=.007). Moreover, urea and creatinine levels were inversely associated with MedDietScore (b+/-SE, -0.05+/-0.02, P=.01, and -0.004+/-0.001, P < .001, respectively). Multiple linear regression analysis revealed that for each 10/55 additional points in diet score, a 3.7-unit increase in CCr rate in women (P < .001) and a 10.1-unit increase in CCr rate in men were evident (P < .001). Further analysis revealed that the CCr rate was positively correlated with the consumption of fruits (rho =0.08, P=.009) and moderate alcohol consumption, and inversely correlated with the consumption of potatoes (rho=-0.11, P < .001), red meat (rho=-0.12, P=.001), and poultry (rho=-0.07, P=.02).

CONCLUSIONS

Greater adherence to the Mediterranean diet was independently associated with reduced urea and creatinine and increased CCr rates among healthy men and women. This finding adds to the knowledge regarding the benefits of a traditional Mediterranean diet in human health.

Effects of chronic ethanol exposure on renal function tests and oxidative stress in kidney

After administration, ethanol and its metabolites go through the kidneys and are excreted into urine. The kidney seems to be the only vital organ generally spared in chronic alcoholics. Therefore, we investigated the multiple effects of chronic ethanol exposure on renal function tests and on oxidative stress related parameters in the kidney. Chronic ethanol (1.6 g ethanol/ kg body weight/ day) exposure did not show any significant change in relative weight (g/ 100g body weight) of kidneys, serum calcium level or glutathione s-transferase activity. However, urea and creatinine concentration in serum, and TBARS level in kidney elevated significantly, while reduced glutathione content and activities of glutathione peroxidase, glutathione reductase and superoxide dismutase diminished significantly after 12 weeks of ethanol exposure. Catalase activity showed increased activity after 4 weeks of ethanol exposure and decreased activity after 12 weeks of ethanol exposure. Genesis of renal ultrastructural abnormalities after 12 weeks of ethanol exposure may be important for the development of functional disturbances. This study revealed that chronic ethanol exposure for longer duration is associated with deleterious effects in the kidney.