Ameliorative effects of clonidine on ethanol induced kidney injury in rats: Potential role for imidazoline-1 receptor

Alcohol Intake and Arterial Hypertension: Retelling of a Multifaceted Story

Alcoholic beverages are common components of diets worldwide and understanding their effects on humans' health is crucial. Because hypertension is the leading risk factor for cardiovascular diseases and all-cause mortality, the relationship of alcohol consumption with blood pressure (BP) has been the subject of extensive investigation. For the purpose of this review, we searched the terms "alcohol", "ethanol", and "arterial hypertension" on Pubmed MeSH and selected the most relevant studies. Short-term studies showed a biphasic BP response after ingestion of high doses of alcohol, and sustained alcohol consumption above 30 g/day, significantly, and dose-dependently, increased the risk for hypertension. These untoward effects of alcoholic beverages on BP can be mediated by a multiplicity of neurohormonal mechanisms. In addition to the effects on BP, excess alcohol intake might contribute to cardiac and renal hypertensive organ damage, although some studies suggest possible benefits of moderate alcohol consumption on additional cardiovascular risk factors, such as diabetes and lipoprotein(a). Some intervention studies and cumulative analyses support the evidence of a benefit of the reduction/withdrawal of alcohol consumption on BP and cardiovascular outcomes. This is why guidelines of scientific societies recommend avoidance or limitation of alcohol intake below one unit/day for women and two units/day for men. This narrative article overviews all these topics, providing an update of the current knowledge on the relationship between alcohol and BP.

Tripterygium Wilfordii Polyglycosides (TP) Ameliorate Alcoholic Kidney Injury in Rats by Regulating Protein Expression Associated with the Nuclear Factor Erythroid 2-Related Factor 2 Signaling Pathway

Objective: To explore the mechanisms of protection of tripterygium wilfordii polyglycosides (TP) against alcoholic kidney injury by regulating Nrf2 signaling pathway in rats. Materials and Methods: Dividing rats into Control, Model, LD, MD and HD groups. The kidney was weighed to calculate kidney index. The morphology of the kidney was observed by HE staining. Nrf2, p-Nrf2 and HO-1 in kidney were detected by immunohistochemistry. Measuring Scr by Jaffe’s method and BUN by diacetyl-oxime method. The renal SOD and MDA were detected by colorimetry. The renal ROS was detected by fluorescence spectrometry. Results: Compared with Control, histopathological changes were observed in Model group, The kidney index, Scr, BUN, renal MDA and ROS concentrations increased significantly (P <0.001). Renal SOD activity, expression of p-Nrf2 and HO-1, p-Nrf2/Nrf2 decreased significantly (P < 0.001). With TP supplement, compared with Model, histopathological was improved, The kidney index, Scr, BUN, renal MDA and ROS concentrations decreased significantly (P <0.05, respectively); Renal SOD activity, p-Nrf2 and HO-1, p-Nrf2/Nrf2 increased significantly (P <0.05, respectively) in TP treated groups (LD, MD and HD). Conclusion: TP can prevent or reduce oxidative stress and attenuate alcoholic kidney injury via regulating Nrf2 signaling pathway in vivo.

Moxonidine ameliorates cardiac injury in rats with metabolic syndrome by regulating autophagy

AIMS

Reduced cardiac autophagy, ischemic injury, sympathetic overactivity, and apoptosis all contribute to metabolic syndrome (MetS)-associated cardiovascular risks. NR4A2, an orphan nuclear receptor NR4A family member, induces autophagy while suppressing apoptosis in myocardial infarction. Moxonidine, a sympathoinhibitor imidazoline1 receptor (I1R) agonist, has beneficial metabolic and hemodynamic effects; however, whether autophagy and/or NR4A2 signaling are involved in moxonidine's cardiovascular effects via I1R activation, is unknown, and is the aim of this study.

MATERIALS AND METHODS

To induce MetS, rats were fed 3 % salt in their diet and 10 % fructose in their drinking water for 12 weeks. MetS-rats were given either moxonidine (6 mg/kg/day, gavage), efaroxan (I1R antagonist, 0.6 mg/kg/day, i.p), both treatments, or vehicles for the last two weeks. Blood pressure, lipid profile, and glycemic control were evaluated. Histopathological examination, circulating cardiac troponin I (c-TnI), proinflammatory interleukin-6 (IL-6), apoptosis (active caspase-3 and Fas-immunostaining), interstitial fibrosis [transforming growth factor-β1 (TGF-β1), Mallory's trichrome staining], and extracellular matrix remodeling [matrix metalloproteinase-9 (MMP-9)], were used to assess cardiac pathology. Cardiac NR4A2 and its downstream factor, p53, as well as autophagic flux markers, SQSTM1/p62, LC3, and Beclin-1 were also determined.

KEY FINDINGS

Moxonidine significantly ameliorated MetS-induced metabolic and hemodynamic derangements and the associated cardiac pathology. Moxonidine restored NR4A2 and p53 myocardial levels and enhanced autophagic flux via modulating SQSTM1/p62, LC3, and Beclin-1. Efaroxan reversed the majority of the moxonidine-induced improvements.

SIGNIFICANCE

The current study suggests that autophagy modulation via I1R activation is involved in moxonidine-mediated cardiac beneficial effects in MetS.

Mitigation of dexamethasone-induced nephrotoxicity by modulating the activity of adrenergic receptors: Implication of Wnt/β-arrestin2/β-catenin pathway

The present study aimed to investigate the role of α and β-adrenergic receptors (βARs) in mediation or modulation of the dexamethasone-induced nephrotoxicity by using different pharmacological interventions. Nephrotoxicity was induced by subcutaneous injection of dexamethasone (10 mg/kg) for 7 days in Wistar albino rats. Eight groups were used: control; dexamethasone; carvedilol; phenylephrine; carvedilol and phenylephrine; propranolol; doxazosin; propranolol and doxazosin. At the end of experiment, rats were euthanized and blood, urine and kidney samples were collected. Serum and urinary creatinine and urinary total protein levels were measured. Also, the renal tissue levels of diacylglycerol (DAG); Akt kinase activity, malondialdehyde (MDA), NADPH oxidase 2 (NOX2), transforming growth factor-β (TGF-β), Wnt3A and β-catenin were recorded. Furthermore, histopathological and β-arrestin2-immunohistochemical examinations of renal tissues were performed. Results: Dexamethasone induced glomerular damage, proteinuria, renal oxidative stress and upregulated the renal Wnt/β-arrestin2/β-catenin pathway and the profibrotic signals. Blocking the α1 and βARs by carvedilol reduced the dexamethasone-induced nephrotoxicity. Pre-injection of phenylephrine did not reduce the reno-protective action of carvedilol. Blocking the βARs only by propranolol reduced the dexamethasone-induced nephrotoxicity to the same extent of carvedilol group. Blocking the α1ARs only by doxazosin reduced dexamethasone-induced nephrotoxicity to a higher extent than other treatments. However, combined use of propranolol and doxazosin did not synergize the reno-protective effects of doxazosin. Conclusion: Dexamethasone induces nephrotoxicity, possibly, by upregulating the Wnt/β-arrestin2/β-catenin pathway. Blocking either α1ARs or βARs can effectively protect against the dexamethasone-induced nephrotoxicity. However, combined blocking of α1ARs and βARs does not synergize the reno-protective effects.

Corticosterone-Mediated Physiological Stress Alters Liver, Kidney, and Breast Muscle Metabolomic Profiles in Chickens

Simple Summary

Corticosterone is the major stress hormone in birds and research has shown that an increase in corticosterone can have adverse effects on bird health (e.g., predisposition to disease) production performance metrics. However, it is not currently possible to monitor commercial flocks for stress before performance is affected. A popular model of chicken stress involves administering corticosterone to chickens though their drinking water. However, corticosterone is non-polar so it must first be dissolved in ethanol, which means that the chickens are also drinking ethanol. In this study, an untargeted nuclear magnetic resonance-based metabolomics approach was used to investigate the effects of this model of stress in chickens, as well as the effects corticosterone on the chicken kidney, liver, and breast muscle metabolomes. We hypothesized that physiological stress modulates the metabolome of liver, kidney, and breast muscle due to increases in catabolism and gluconeogenesis. The administration of corticosterone altered the chicken liver, kidney, and breast muscle metabolomes. However, the ethanol carrier affected the metabolome of all three tissues, which indicated that corticosterone should be administered in an alternate fashion in future metabolomics studies to remove the confounding effects of ethanol. Furthermore, future research should focus on relating metabolite changes in tissues to non-destructive markers like blood, feces, or feathers to develop new diagnostic tools to better monitor on-farm stress during production.

Abstract

The impact of physiological stress on the metabolomes of liver, kidney, and breast muscle was investigated in chickens. To incite a stress response, birds were continuously administered corticosterone (CORT) in their drinking water at three doses (0, 10, and 30 mg L⁻¹), and they were sampled 1, 5, and 12 days after the start of the CORT administration. To solubilize CORT, it was first dissolved in ethanol and then added to water. The administration of ethanol alone significantly altered branched chain amino acid metabolism in both the liver and the kidney, and amino acid and nitrogen metabolism in breast muscle. CORT significantly altered sugar and amino acid metabolism in all three tissues, but to a much greater degree than ethanol alone. In this regard, CORT administration significantly altered 11, 46, and 14 unique metabolites in liver, kidney, and breast muscle, respectively. Many of the metabolites that were affected by CORT administration, such as mannose and glucose, were previously linked to increases in glycosylation and gluconeogenesis in chickens under conditions of production stress. Moreover, several of these metabolites, such as dimethylglycine, galactose, and carnosine were also previously linked to reduced quality meat. In summary, the administration of CORT in chickens significantly modulated host metabolism. Moreover, results indicated that energy potentials are diverted from muscle anabolism to muscle catabolism and gluconeogenesis during periods of stress.

Causal effect of alcohol use on the risk of end-stage kidney disease and related comorbidities: a Mendelian randomization study

BACKGROUND

An inverse observational association between alcohol use and the risk of chronic kidney disease (CKD) or end-stage kidney disease (ESKD) has been reported. The causal effect of alcohol use on the risk of ESKD warrants additional investigation.

METHODS

The study was an observational cohort study investigating the UK Biobank and performed Mendelian randomization (MR) analysis. Amounts of alcohol use were collected using a touchscreen questionnaire. In the observational analysis, 212,133 participants without prevalent ESKD were studied, and the association between alcohol use and the risk of prevalent CKD or incident ESKD was investigated. The genetic analysis included 337,138 participants of white British ancestry. For one-sample MR, an analysis based on a polygenic risk score (PRS) was conducted with genetically predicted alcohol intake. The MR analysis investigated ESKD outcome and related comorbidities.

RESULTS

Lower alcohol use was observationally associated with a higher risk of prevalent CKD or incident ESKD. However, the genetic risk of CKD was significantly associated with lower alcohol use, suggesting reverse causation. A higher PRS for alcohol use was significantly associated with a higher risk of ESKD (per units of one phenotypical alcohol drink; adjusted odds ratio of 1.16 [95% confidence interval, 1.02-1.31]) and related comorbidities, including hypertension, diabetes mellitus, obesity, and central obesity.

CONCLUSION

The inverse observational association between alcohol use and the risk of CKD or ESKD may have been affected by reverse causation. Our study supports a causal effect of alcohol use on a higher risk of ESKD and related predisposing comorbidities.

Alcohol promotes renal fibrosis by activating Nox2/4-mediated DNA methylation of Smad7

Alcohol consumption causes renal injury and compromises kidney function. The underlying mechanism of the alcoholic kidney disease remains largely unknown. In the present study, an alcoholic renal fibrosis animal model was first employed which mice received liquid diet containing alcohol for 4 to 12 weeks. The Masson's Trichrome staining analysis showed that kidney fibrosis increased at week 8 and 12 in the animal model that was further confirmed by albumin assay, Western blot, immunostaining and real-time PCR of fibrotic indexes (collagen I and α-SMA). In vitro analysis also confirmed that alcohol significantly induced fibrotic response (collagen I and α-SMA) in HK2 tubular epithelial cells. Importantly, both in vivo and in vitro studies showed alcohol treatments decreased Smad7 and activated Smad3. We further determined how the alcohol affected the balance of Smad7 (inhibitory Smad) and Smad3 (regulatory Smad). Genome-wide methylation sequencing showed an increased DNA methylation of many genes and bisulfite sequencing analysis showed an increased DNA methylation of Smad7 after alcohol ingestion. We also found DNA methylation of Smad7 was mediated by DNMT1 in ethyl alcohol (EtOH)-treated HK2 cells. Knockdown of Nox2 or Nox4 decreased DNMT1 and rebalanced Smad7/Smad3 axis, and thereby relieved EtOH-induced fibrotic response. The inhibition of reactive oxygen species by the intraperitoneal injection of apocynin attenuated renal fibrosis and restored renal function in the alcoholic mice. Collectively, we established novel in vivo and in vitro alcoholic kidney fibrosis models and found that alcohol induces renal fibrosis by activating oxidative stress-induced DNA methylation of Smad7. Suppression of Nox-mediated oxidative stress may be a potential therapy for long-term alcohol abuse-induced kidney fibrosis.

Effect of imidazoline-1 receptor agonists on renal dysfunction in rats associated with chronic, sequential fructose and ethanol administration

Insulin resistance and chronic alcoholism are risk factors for renal dysfunction. This study investigated the therapeutic effects of two imidazoline-1 receptor (I1R) agonists on renal dysfunction in rats after chronic, sequential fructose and ethanol administration. Daily drinking water was supplemented with fructose (10%, w/v) for 12 weeks and then with ethanol (20%, v/v) for another 8 weeks. Rats were treated with rilmenidine and clonidine in the last two weeks of the study. Blood glucose and serum insulin (sIns) levels, lipid profiles, kidney function and renal histopathology were evaluated at the end of the experiment. Additionally, renal gene expression of nischarin, phosphatidylcholine-specific phospholipase C (PC-PLC) and prostaglandin E2 (PGE2) were measured. Renal levels of superoxide dismutase (SOD), malondialdehyde (MDA), myeloperoxidase (MPO), inducible nitric oxide synthase (iNOS) and total NO (tNO) were detected, and we determined the relative renal gene expression levels of alpha smooth muscle actin (α-SMA), hydroxyproline, interleukin 10 (IL-10), tumour necrosis factor alpha (TNF-α) and caspase-3. The results showed significant deterioration of blood glucose, sIns, lipid profiles, kidney function and renal histopathology in fructose/ethanol-fed rats. Additionally, markers of inflammation, fibrosis, apoptosis and oxidative stress were upregulated. The administration of rilmenidine or clonidine significantly improved blood glucose and sIns levels and reduced renal dysfunction. Our work showed that chronic, sequential fructose and ethanol administration induced fasting hyperglycaemia and renal impairment, and these effects were ameliorated by I1R agonists.

Alcohol Consumption Can be a "Double-Edged Sword" for Chronic Kidney Disease Patients

Excessive drinking of alcohol is becoming a worldwide problem, and people have recognized that there exists a close relationship between chronic kidney disease (CKD) and alcohol consumption. However, there are many inconsistencies between experimental and clinical studies on alcohol consumption and kidney damage. The possible reason for this contradictory conclusion is the complex drinking pattern of humans and some bioactivators in wine. In addition, the design itself of the clinical studies can also produce conflicting interpretations of the results. Considering the benefits of light-to-moderate alcohol consumption, we recommend that CKD patients continue light-to-moderate drinking, which is beneficial to them. Because alcohol consumption can lead to adverse events, we do not advise non-drinkers to start to drink. Although light-to-moderate alcohol consumption may not pose a risk to patients with CKD, the patients’ condition needs to be considered. Consumption of even small amounts of alcohol can be associated with increased death risk. Additional clinical and experimental studies are needed to clarify the effect of alcohol on the kidneys and alcohol consumption on CKD patients.

Investigation of the phytochemical composition and antioxidant properties of chinar (Platanus orientalis L.) leaf infusion against ethanol-induced oxidative stress in rats

Chinar (Platanus orientalis L.) is used in folk medicine against tooth and knee pain, wounds, inflammation, and stomach discomfort; however, the effects of P. orientalis leaf (PO-leaf) infusion on the liver and kidney are unknown. The aim of this study was to investigate the phytochemical composition and antioxidant properties of an infusion obtained from dried P. orientalis leaves against ethanol-induced oxidative stress (OS) in rats. After a toxicity test, thirty male Wistar rats were divided into five groups: Control, Ethanol 20%, Ethanol 20% + Silymarin (10 mg/kg), Ethanol 20% + PO-20 mg/mL infusion, and Ethanol 20% + PO-60 mg/mL infusion. The PO-leaf infusion doses were given ad libitum during 28 days to test the biochemical and antioxidant enzyme levels. According to the results, the PO-leaf contained rich compounds such as benzaldehyde, palmitic acid, 2,4-ditert-butylphenol, stearic acid, octadecanoic acid, linoleic acid, linolenic acid, kaempferol, and kaempferol derivatives. In the Ethanol group, AST, ALT, LDH, GGT, UA, and urea in the serum and GST and malondialdehyde (MDA) in the liver and erythrocyte tissues showed a significant increase compared to the Control group. AST, LDH, GGT, UA, and LDL-C levels in the serum and MDA (all tissues) significantly decreased in the Ethanol + PO-60 mg/mL group compared to the Ethanol group. SOD, GPx, and CAT activities in the kidney tissue of the Ethanol group showed a significant decrease compared to the Control group, whereas the GPx activity in kidney tissue in all of the treatment groups increased significantly compared to the Ethanol group. These findings suggest that the administration of the determined PO-leaf infusion doses might have a protective role against ethanol-induced liver and kidney damage in rats.

Imidazoline receptors agonists: possible mechanisms of endothelioprotection

Imidazoline receptor agonists are one of the groups of contemporary antihypertensive drugs with the pleiotropic cardiovascular effects. In this review, the historical, physiological, pathophysiological aspects concerning imidazoline receptor agonists and possible mechanisms for their participation in endothelioprotection were considered. Illuminated the molecular biology of each subtype of imidazoline receptors and their significance in the pharmacological correction of cardiovascular disease.

IR type 1 are localized in the brain nucleus, carrying out the descending tonic control of sympathetic activation, as well as in the endothelial cells of the vessels and kidneys. Their activation leads to a decrease in blood pressure, slowing the remodeling of the vascular wall and increasing sodium nares. IR type 2 is expressed predominantly in the adrenal gland, fat and muscle tissues. The physiological effects of their stimulation are associated with an increase in glucose utilization by peripheral tissues. IR type 3 are mainly present in pancreatic cells and are associated with the regulation of insulin secretion. Their stimulation leads to an increase in insulin liberation. Thus, IR agonists are able to improve endothelial function through various mechanisms, including blood pressure reduction, improvement in metabolic profile, and direct positive effects on the vascular wall.

Current information on the pharmacological effects of this group compounds allows us to conclude that they are a promising group for correcting endothelial dysfunction and complications associated with it.