Oxidant stress in hyperlipidemia-induced renal damage

Prevalence and assessment of risk factors of chronic kidney disease in the ASIR region of Saudi Arabia

Introduction

Chronic kidney disease (CKD) is a major health concern in Saudi Arabia. The prevalence of CKD and associated risk factors in Saudi Arabia's general population are not efficiently studied. The goal of this research is to determine the prevalence rate of CKD in the ASIR region and its associated epidemiological risk factors.

Methodology

This is a cross-sectional study that used a comprehensive direct questionnaire to collect data on CKD prevalence and risk factors in the ASIR region of Saudi Arabia. The study was carried out in different age groups. Demographic characteristics, presence of CKD, and associated factors such as a history of acute kidney disease, obstructive sleep apnoea, family history, history of non-steroid anti-inflammatory drugs (NSAID), smoking status, comorbidities, and history of periodontal diseases were asked. The survey tool was validated through a pilot study, and a statistical p value of 0.05 was considered significant.

Results

A total of 967 participants were included in the study, with a CKD prevalence rate of 1.9%. Sex, history of acute kidney disease, obstructive sleep apnoea, family history of kidney disease, smoking, diabetes, peptic ulcer disease, hypertension and hyperlipidemia were commonly found to be associated with CKD. A binary logistic regression model was carried out to assess the risk factors for CKD. Sex, history of acute kidney disease, family history of kidney disease, obstructive sleep apnoea, smoking status, peptic ulcer, diabetes, hypertension, hyperlipidemia, hypertension and diabetes, two or more comorbidities and NSAID use had an increased risk of CKD.

Conclusion

Sex, history of acute kidney disease, obstructive sleep apnoea, family history, smoking, diabetes, hypertension, peptic ulcer, hyperlipidemia, multi-comorbidity, and use of NSAIDs are all associated with an increased risk of CKD. The prevalence of CKD in this study is comparatively lower when compared to other regions in Saudi Arabia.

Swertiamarin mitigates nephropathy in high-fat diet/streptozotocin-induced diabetic rats by inhibiting the formation of advanced glycation end products

CONTEXT

The molecular mechanism by which Swertiamarin (SM) prevents advanced glycation end products (AGEs) induced diabetic nephropathy (DN) has never been explored.

OBJECTIVE

To evaluate the effect of SM in preventing the progression of DN in high fat diet-streptozotocin-induced diabetic rats.

MATERIALS AND METHODS

After 1 week of acclimatisation, the rats were divided randomly into five groups as follows: (1) Control group, which received normal chow diet; (2) High-fat diet (HFD) group which was fed diet comprising of 58.7% fat, 27.5% carbohydrate and 14.4% protein); (3) Aminoguanidine (AG) group which received HFD + 100 mg/k.b.w.AG (intraperitoneal); (4) Metformin (Met) group which received HFD + 70 mg/k.b.w. the oral dose of Met and (5) SM group which was supplemented orally with 50 mg/k.b.w.SM along with HFD. After 12 weeks all HFD fed animals were given a single 35 mg/k.b.w. dose of streptozotocin with continuous HFD feeding for additional 18 weeks. Later, various biochemical assays, urine analyses, histopathological analysis of kidneys, levels of AGEs, expression of various makers, and in-silico analysis were performed.

RESULTS

The diabetic group demonstrated oxidative stress, increased levels of AGEs, decreased renal function, fibrosis in the renal tissue, higher expression of the receptor for advanced glycation end products (RAGE), which were ameliorated in the SM treated group. In-silico analysis suggests that SM can prevent the binding of AGEs with RAGE.

CONCLUSIONS

SM ameliorated DN by inhibiting the oxidative stress induced by AGEs.HighlightsSM reduces the levels of hyperglycaemia-induced advanced glycation end products in serum and renal tissue.SM prevents renal fibrosis by inhibiting the EMT in the kidney tissue.The in-silico analysis proves that SM can inhibit the binding of various AGEs with RAGE, thereby inhibiting the AGE-RAGE axis.

NAD+ Protects against Hyperlipidemia-induced Kidney Injury in Apolipoprotein E-deficient Mice

Background: Hyperlipidemia is an independent risk factor for kidney injury. Several studies have shown that nicotinamide adenine dinucleotide (NAD+) is an important coenzyme involved in normal body metabolism. Therefore, this study aimed to investigate the possible protective effects of NAD+ against hyperlipidemia-induced kidney injury in apolipoprotein Edeficient (ApoE-/-) mice.

Methods: Twenty-five eight-week-old male ApoE-/- mice were randomly assigned into four groups: normal diet (ND), ND supplemented with NAD+ (ND+NAD+), high-fat diet (HFD), and HFD supplemented with NAD+ (HFD+NAD+). The mice were subjected to their respective diets for a duration of 16 weeks. Blood samples were obtained from the inferior vena cava, collected in serum tubes, and stored at -80°C until use. Kidney tissues was fixed in 10% formalin and then embedded in paraffin for histological evaluation. The remainder of the kidney tissues was snapfrozen in liquid nitrogen for Western blot analysis.

Results: Metabolic parameters (total cholesterol, triglycerides, low-density lipoprotein-cholesterol, creatinine, and blood urea nitrogen) were significantly higher in the HFD group compared to the other groups. Histological analysis revealed prominent pathological manifestations in the kidneys of the HFD group. The HFD+NAD+ group showed increased levels of oxidative stress markers (NRF2 and SOD2) and decreased levels of NOX4 compared to the HFD group. Furthermore, the HFD group exhibited higher levels of TGF-β, Smad3, Collagen I, Collagen III, Bax, and Bak compared to the other groups. NAD+ supplementation in the HFD+NAD+ group significantly increased the levels of SIRT3, HO-1, Bcl-2, and Bcl-xL compared to the HFD group. Additionally, NF-κB protein expression was higher in the HFD group than in the HFD+NAD+ group.

Conclusion: These findings demonstrated that NAD+ may hold potential as a clinical treatment for kidney injury caused by hyperlipidemia.

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Network Pharmacology and Molecular Docking Validation to Explore the Pharmacological Mechanism of Zhuling Decoction against Nephrotic Syndrome

BACKGROUND

In recent years, the incidence and prevalence of Nephrotic Syndrome (NS) have been increasing. Zhuling Decoction (ZLD), a classical Chinese medicine, has been clinically proven to be effective for the treatment of NS. However, its underlying mechanism and pharmacodynamic substances remain unclear.

OBJECTIVE

This study aimed to explore the mechanism of action and chemical components of ZLD against NS using network pharmacology and molecular docking.

METHODS

Traditional Chinese Medicine Systems Pharmacology (TCMSP), Bioinformatics Analysis Tool for Molecular Mechanism of Traditional Chinese Medicines (BATMAN-TCM), and SwissTargetPrediction databases were used to screen the principal ingredients and the associated targets of ZLD. NS-related targets were obtained from the Online Mendelian Inheritance in Man (OMIM), GeneCards, Therapeutic Target Database (TTD), and Drugbank databases. Shared targets were derived by the intersection of ZLD- and NS-associated targets. Protein-interaction relationships were analyzed using the STRING database and Cytoscape. A visualized drug-active compound-target network of ZLD was established using Cytoscape. Analyses of gene enrichment were performed using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) methods by the Database for Annotation, Visualization, and Integrated Discovery (DAVID) database. Molecular docking was performed to assess the binding activity between active components and hub targets.

RESULTS

Polyporusterone E, cerevisterol, alisol B, and alisol B 23-acetate were the primary potential ingredients of ZLD. HMGCR, HSD11B1, NOS2, NR3C1, and NR3C2 were the hub targets of ZLD against NS. Molecular docking showed that polyporusterone E, cerevisterol, and alisol B had high binding activities with targets HMGCR, HSD11B1, and NOS2.

CONCLUSION

In summary, this study suggests that the main active compounds (polyporusterone E, cerevisterol, alisol B) may have important roles for ZLD acting against NS by binding to hub targets (HMGCR, HSD11B1, and NOS2) and modulating PI3K-Akt, Ras, MAPK, and HIF-1 signaling pathways.

The role of exercise in improving hyperlipidemia-renal injuries induced by a high-fat diet: a literature review

A diet that is high in sugar and fat is a precursor to various chronic diseases, especially hyperlipidemia. Patients with hyperlipidemia have increased levels of plasma free fatty acids and an ectopic accumulation of lipids. The kidney is one of the main organs affected by this disease and, recently, there have been more studies conducted on renal injury caused by hyperlipidemia. The main pathological mechanism is closely related to renal lipotoxicity. However, in different kidney cells, the reaction mechanism varies due to the different affinities of the lipid receptors. At present, it is believed that in addition to lipotoxicity, hyperlipidemia induced-renal injury is also closely related to oxidative stress, endoplasmic reticulum stress, and inflammatory reactions, which are the result of multiple factors. Exercise plays an important role in the prevention of various chronic diseases and recently emerging researches indicated its positive effects to renal injury caused by hyperlipidemia. However, there are few studies summarizing the effects of exercise on this disease and the specific mechanisms need to be further explored. This article summarizes the mechanisms of hyperlipidemia induced-renal injury at the cellular level and discusses the ways in which exercise may regulate it. The results provide theoretical support and novel approaches for identifying the intervention target to treat hyperlipidemia induced-renal injury.

The association of apolipoprotein B with chronic kidney disease in the Chinese population

Background

Whether serum apolipoprotein B (ApoB) is a risk factor for the development of Chronic kidney disease (CKD) has not been fully established in the general population. Therefore, our study evaluated the correlation between serum ApoB level and CKD to look for an alternative approach for CKD prevention and treatment in the general population.

Methods

There were 146,533 participants in this cross-sectional study. 3,325 participants with more than 2 measurements were enrolled in the retrospective longitudinal study with at least a 3-year follow-up. ApoB was measured by the immunoturbidimetric method in 6 centers. Our study defined CKD as an estimated glomerular filtration rate (eGFR) < 90 mL/min/1.73 m². The Spearman rank correlation analysis and the Random Forest algorithm were applied to rank the importance of variables determining the levels of eGFR. We used the logistic regression model to explain the correlation between serum ApoB and CKD. We used the Cox model to detect the correlation between baseline serum ApoB and the subsequent occurrence of CKD.

Results

Based on a cross-sectional study, 66.5% of the participants were males, with a median age of 49 (interquartile range [IQR] 43-55). Compared to the non-CKD group, the CKD group has higher levels of lipid profile and fasting glucose as well as the proportion of hypertension and hyperuricemia. The Spearman rank correlation analysis and the Random Forest algorithm revealed that ApoB has the highest correlation with eGFR decline among lipid profiles. The logistic regression analysis revealed that ApoB had a positive correlation with the prevalence of CKD after fully controlling confounders (odds ratio [OR], 1.07; 95% confidence interval [CI]: 1.02-1.11). Moreover, baseline ApoB level was correlated with a new-onset CKD in the longitudinal cohort after full adjustment for confounding factors (hazard ratio [HR], 1.61; 95% CI: 1.02-2.54). The correlation between ApoB level and the new-onset CKD was consistently observed in all sensitivity analyses.

Conclusion

Serum ApoB had the strongest correlation with CKD among all lipid variables. Moreover, high serum ApoB levels might precede the occurrence of CKD, suggesting that monitoring and reducing serum ApoB levels may provide an alternative method to prevent and treat CKD.

Endothelial dysfunction: developmental mechanisms and therapeutic strategies

Introduction: Every year the importance of the normal functioning of the endothelial layer of the vascular wall in maintaining the health of the body becomes more and more obvious.

The physiological role of the endothelium: The endothelium is a metabolically active organ actively involved in the regulation of hemostasis, modulation of inflammation, maintenance of hemovascular homeostasis, regulation of angiogenesis, vascular tone, and permeability.

Risk factors for the development of endothelial dysfunction: Currently, insufficient bioavailability of nitric oxide is considered the most significant risk factor for endothelial dysfunction.

Mechanisms of development of endothelial dysfunction: The genesis of endothelial dysfunction is a multifactorial process. Among various complex mechanisms, this review examines oxidative stress, inflammation, hyperglycemia, vitamin D deficiency, dyslipidemia, excess visceral fat, hyperhomocysteinemia, hyperuricemia, as well as primary genetic defect of endotheliocytes, as the most common causes in the population underlying the development of endothelial dysfunction.

Markers of endothelial dysfunction in various diseases: This article discusses the main biomarkers of endothelial dysfunction currently used, as well as promising biomarkers in the future for laboratory diagnosis of this pathology.

Therapeutic strategies: Therapeutic approaches to the endothelium in order to prevent or reduce a degree of damage to the vascular wall are briefly described.

Conclusion: Endothelial dysfunction is a typical pathological process involved in the pathogenesis of many diseases. Thus, pharmacological agents with endothelioprotective properties can provide more therapeutic benefits than a drug without such an effect.

Discordance between LDL-C and Apolipoprotein B Levels and Its Association with Renal Dysfunction: Insights from a Population-Based Study

Low-density lipoprotein cholesterol (LDL-C) and apolipoprotein B (ApoB) are established markers of atherosclerotic cardiovascular disease (ASCVD), but when concentrations are discordant ApoB is the superior predictor. Chronic kidney disease (CKD) is associated with ASCVD, yet the independent role of atherogenic lipoproteins is contentious. Four groups were created based upon high and low levels of ApoB and LDL-C. Continuous and categorical variables were compared across groups, as were adjusted markers of CKD. Logistic regression analysis assessed association(s) with CKD based on the groups. Subjects were categorised by LDL-C and ApoB, using cut-off values of >160 mg/dL and >130 mg/dL, respectively. Those with low LDL-C and high ApoB, compared to those with high LDL-C and high ApoB, had significantly higher body mass index (30.7 vs. 30.1 kg/m²) and waist circumference (106.1 vs. 102.7 cm) and the highest fasting blood glucose (117.5 vs. 112.7 mg/dL), insulin (16.6 vs. 13.1 μU/mL) and homeostatic model assessment of insulin resistance (5.3 vs. 3.7) profiles (all p < 0.001). This group, compared to those with high LDL-C and high ApoB, also had the highest levels of urine albumin (2.3 vs. 2.2 mg/L), log albumin-creatinine ratio (2.2 vs. 2.1 mg/g) and serum uric acid (6.1 vs. 5.6 mg/dL) and the lowest estimated glomerular filtration rate (81.3 vs. 88.4 mL/min/1.73 m²) (all p < 0.001). In expanded logistic regression models, using the low LDL-C and low ApoB group as a reference, those with low LDL-C and high ApoB had the strongest association with CKD, odds ratio (95% CI) 1.12 (1.08-1.16). Discordantly high levels of ApoB are independently associated with increased likelihood of CKD. ApoB remains associated with metabolic dysfunction, regardless of LDL-C.

Angelica Polysaccharide Antagonizes 5-FU-Induced Oxidative Stress Injury to Reduce Apoptosis in the Liver Through Nrf2 Pathway

Oxidative stress induced by chemotherapeutic agents causes hepatotoxicity. 5-Fluorouracil (5-FU) has been found to have a variety of side effects, but its toxic effect on the liver and the mechanism are still unclear. Angelica polysaccharide (ASP), the main active ingredient of Dang Gui, has antioxidative stress effects. In this study, we investigated the antagonistic effects of ASP on 5-FU-induced injury in the mouse liver and human normal liver cell line MIHA and the possible mechanism. Our results show that ASP inhibited 5-FU-induced the decrease in Bcl-2 protein and the increase in Bax protein. ASP alleviated 5-FU-induced the increase in alanine aminotransferase (ALT), triglyceride (TG), and aspartate aminotransferase (AST) content; hepatic steatosis; and liver fibrosis. ASP restored 5-FU-induced swelling of mitochondria and the endoplasmic reticulum. 5-FU promoted the expression of Keap1 and increased the binding to NF-E2-related factor 2 (Nrf2) to reduce the nuclear translocation of Nrf2, thereby weakening the transcriptional activity of Nrf2 to inhibit the expression of HO-1; reducing the activity of GSH, SOD, and CAT to increase ROS content; and aggravating DNA damage (indicated by the increase in 8-OHdG). However, ASP reversed these reactions. In conclusion, ASP attenuated the 5-FU-induced Nrf2 pathway barrier to reduce oxidative stress injury and thereby inhibit the disorder of lipid anabolism and apoptosis. The study provides a new protectant for reducing the hepatic toxicity caused by 5-FU and a novel target for treating the liver injury.

Apolipoprotein B is a risk factor for end-stage renal disease

BACKGROUND

Apolipoprotein B (ApoB), a constituent of lipid particles, is known to increase the risk of cardiovascular diseases. However, the association between ApoB and end-stage renal disease (ESRD) remains to be resolved. Our objective was to determine whether the ApoB concentration has an association with the risk of ESRD.

METHODS

Serum ApoB, ApoA1, conventional lipid parameters and lipid subfractions were analyzed in 9403 subjects. The hazard ratio (HR) for the risk of ESRD was calculated using tertiles of ApoB concentration.

RESULTS

ESRD developed in 110 patients (1.2%) during 10 years of follow-up. Several lipid parameters were compared for their association with the risk of ESRD, of which ApoB was best and its relationship was also independent of other clinical parameters. Individuals in the second and third ApoB tertiles had a higher risk of ESRD than those in the first tertile, with HRs of 1.5 [95% confidence interval (CI) 0.89-2.61] and 2.6 (1.56-4.20), respectively. A high ApoB:ApoA1 ratio was associated with a higher risk of ESRD, but ApoA1 had no independent association. Even after adjusting the competing risk for all-cause death, high ApoB concentrations had an association with the risk of ESRD.

CONCLUSIONS

High ApoB concentration is associated with a higher risk of ESRD, despite adjustment for other lipid and clinical parameters. Accordingly, the monitoring of ApoB may be helpful for the prediction of ESRD.

Exercise reduces hyperlipidemia-induced kidney damage in apolipoprotein E-deficient mice

Hyperlipidemia is a risk factor of kidney damage that can lead to chronic kidney disease. Studies have shown that exercise reduces kidney damage; however, the specific mechanisms underlying the protective effects of exercise remain unclear. For 12 weeks, 8-week-old male apolipoprotein E-deficient (ApoE^-/-) mice were randomly divided into four treatment groups (n=7/group) as follows: Mice fed a normal diet (ND group); mice fed a ND and exercised (ND + E group); mice fed a high-fat diet (HD group); and mice fed a HD and exercised (HD + E group). Exercise training consisted of swimming for 40 min, 5 days/week. Metabolic parameters, such as low-density lipoprotein-cholesterol, total cholesterol and creatinine levels were higher in the ApoE^-/- HD mice compared with those in the ApoE^-/- HD + E mice. Serum levels of glutathione peroxidase and superoxide dismutase were significantly decreased in the HD group compared with those in the HD + E group. Significant pathological changes were observed in the HD + E group compared with in the HD group. Immunohistochemistry and immunoblotting revealed increased levels of oxidative stress (nuclear factor erythroid-2-related factor 2) and fibrosis (Smad3 and TGF-β) markers in the ApoE^-/- HD group; however, the expression levels of these markers were significantly decreased in the ApoE^-/- HD + E group. Furthermore, NF-κB expression in the HD + E group was significantly lower compared with that in the HD group. These results suggested that exercise may exert protective effects against kidney damage caused by hyperlipidemia.

The vital role for nitric oxide in intraocular pressure homeostasis

Catalyzed by endothelial nitric oxide (NO) synthase (eNOS) activity, NO is a gaseous signaling molecule maintaining endothelial and cardiovascular homeostasis. Principally, NO regulates the contractility of vascular smooth muscle cells and permeability of endothelial cells in response to either biochemical or biomechanical cues. In the conventional outflow pathway of the eye, the smooth muscle-like trabecular meshwork (TM) cells and Schlemm's canal (SC) endothelium control aqueous humor outflow resistance, and therefore intraocular pressure (IOP). The mechanisms by which outflow resistance is regulated are complicated, but NO appears to be a key player as enhancement or inhibition of NO signaling dramatically affects outflow function; and polymorphisms in NOS3, the gene that encodes eNOS modifies the relation between various environmental exposures and glaucoma. Based upon a comprehensive review of past foundational studies, we present a model whereby NO controls a feedback signaling loop in the conventional outflow pathway that is sensitive to changes in IOP and its oscillations. Thus, upon IOP elevation, the outflow pathway tissues distend, and the SC lumen narrows resulting in increased SC endothelial shear stress and stretch. In response, SC cells upregulate the production of NO, relaxing neighboring TM cells and increasing permeability of SC's inner wall. These IOP-dependent changes in the outflow pathway tissues reduce the resistance to aqueous humor drainage and lower IOP, which, in turn, diminishes the biomechanical signaling on SC. Similar to cardiovascular pathogenesis, dysregulation of the eNOS/NO system leads to dysfunctional outflow regulation and ocular hypertension, eventually resulting in primary open-angle glaucoma.

Parthenolide ameliorates tweak-induced podocytes injury

Parthenolide (PTL) is a natural product from the shoots of Tanacetum parthenium, which has immunomodulatory effects in multiply type of diseases. This study aimed to explore the effect and the underlying mechanism of PTL on the anti-apoptotic and anti- inflammatory ability of tweak-induced podocytes. Conditionally immortalized mouse podocytes were incubated with Tumor necrosis factor-like weak inducer of apoptosis (Tweak, 100 ng/ml), PTL(10 µM) or Tweak + PTL for 12 h, 24 and 48 h, respectively. Podocytes viability was detected by CCK-8 assay. Tweak and Cxcl16 expression were evaluated by western blot and immunofluorescence assay. Dil-oxLDL stain was detected by immunofluorescence analysis. Intracellular Total Cholesterol (TC) content was measured through TC detection Kit. These results demonstrated that the podocytes cells viability was gradually decreased after treatment with different concentrations of Tweak (0, 50, 100, 150). Tweak and Cxcl16 protein expression in mouse podocytes treated with tweak were remarkably elevated and were found to have higher intracellular lipid accumulation compared with the control group, whereas co-administration with PTL, tweak and Cxcl16 expression as well as the intracellular lipid accumulation were notablely decreased in tweak-induced podocytes. Therefore, our conclusion was that tweak and Cxcl16 were involved in the regulation of tweak-induced podocytes injury. Meanwhile, the anti-apoptotic and anti-inflammatory effect of PTL may be correlated with the tweak and Cxcl16 expression decreased.

Lipotoxicity and Diabetic Nephropathy: Novel Mechanistic Insights and Therapeutic Opportunities

Lipotoxicity is characterized by the ectopic accumulation of lipids in organs different from adipose tissue. Lipotoxicity is mainly associated with dysfunctional signaling and insulin resistance response in non-adipose tissue such as myocardium, pancreas, skeletal muscle, liver, and kidney. Serum lipid abnormalities and renal ectopic lipid accumulation have been associated with the development of kidney diseases, in particular diabetic nephropathy. Chronic hyperinsulinemia, often seen in type 2 diabetes, plays a crucial role in blood and liver lipid metabolism abnormalities, thus resulting in increased non-esterified fatty acids (NEFA). Excessive lipid accumulation alters cellular homeostasis and activates lipogenic and glycogenic cell-signaling pathways. Recent evidences indicate that both quantity and quality of lipids are involved in renal damage associated to lipotoxicity by activating inflammation, oxidative stress, mitochondrial dysfunction, and cell-death. The pathological effects of lipotoxicity have been observed in renal cells, thus promoting podocyte injury, tubular damage, mesangial proliferation, endothelial activation, and formation of macrophage-derived foam cells. Therefore, this review examines the recent preclinical and clinical research about the potentially harmful effects of lipids in the kidney, metabolic markers associated with these mechanisms, major signaling pathways affected, the causes of excessive lipid accumulation, and the types of lipids involved, as well as offers a comprehensive update of therapeutic strategies targeting lipotoxicity.

Cardiac protection of functional chicken-liver hydrolysates on the high-fat diet induced cardio-renal damages via sustaining autophagy homeostasis

BACKGROUND

Cardio-renal syndrome (CRS) is an integrative problem related to chronic malnutrition, obesity, etc. Amino acids and peptides are regarded as protective and essential for tissues. Pepsin-digested chicken liver hydrolysates (CLHs), which are made from the byproducts of the poultry industry, are amino-acid based and of animal origin, and may be protective against the myocardial and renal damage induced by a high-fat diet (HFD).

RESULTS

Our results showed that CLHs contain large quantities of anserine, taurine, and branched-chain amino acids (BCAAs), and supplementing the diet with CLHs reduced (P < 0.05) weight gain, liver weight, peri-renal fat mass / adipocyte-area sizes, serum total cholesterol (TC), aspartate aminotransferase (AST), and low-density lipoprotein cholesterol (LDLC) levels in HFD-fed mice but increased (P < 0.05) serum high-density lipoprotein cholesterol (HDLC) levels. By histological analyses, CLHs alleviated (P < 0.05) renal lipid deposition and fibrosis, as well as cardiac fibrosis and inflammation of HFD-fed mice. Meanwhile, increased (P < 0.05) inflammatory and fibrotic cytokines levels in the myocardia of the HFD-fed mice were downregulated (P < 0.05) by CLH supplementation. Regarding autophagy-related protein levels, protective effects of CLHs on the myocardia against HFD feeding may result from the early blockade of the autophagy pathway to prevent autophagosome accumulation.

CONCLUSION

Functional CLHs could be a novel food ingredient as a cardio-renal protective agent against a high-fat dietary habit in a niche market. © 2020 Society of Chemical Industry.

Cyanate Induces Oxidative Stress Injury and Abnormal Lipid Metabolism in Liver through Nrf2/HO-1

Chronic kidney disease (CKD) is problem that has become one of the major issues affecting public health. Extensive clinical data suggests that the prevalence of hyperlipidemia in CKD patients is significantly higher than in the general population. Lipid metabolism disorders can damage the renal parenchyma and promote the occurrence of cardiovascular disease (CVD). Cyanate is a uremic toxin that has attracted widespread attention in recent years. Usually, 0.8% of the molar concentration of urea is converted into cyanate, while myeloperoxidase (MPO) catalyzes the oxidation of thiocyanate to produce cyanate at the site of inflammation during smoking, inflammation, or exposure to environmental pollution. One of the important physiological functions of cyanate is protein carbonylation, a non-enzymatic post-translational protein modification. Carbamylation reactions on proteins are capable of irreversibly changing protein structure and function, resulting in pathologic molecular and cellular responses. In addition, recent studies have shown that cyanate can directly damage vascular tissue by producing large amounts of reactive oxygen species (ROS). Oxidative stress leads to the disorder of liver lipid metabolism, which is also an important mechanism leading to cirrhosis and liver fibrosis. However, the influence of cyanate on liver has remained unclear. In this research, we explored the effects of cyanate on the oxidative stress injury and abnormal lipid metabolism in mice and HL-7702 cells. In results, cyanate induced hyperlipidemia and oxidative stress by influencing the content of total cholesterol (TC), high-density lipoprotein (HDL), low-density lipoprotein (LDL), superoxide dismutase (SOD), catalase (CAT) in liver. Cyanate inhibited NF-E2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), and the phosphorylation of adenosine 5'monophosphate-activated protein kinase (AMPK), activated the mTOR pathway. Oxidative stress on the cells reduced significantly by treating with TBHQ, an antioxidant, which is also an activator of Nrf2. The activity of Nrf2 was rehabilitated and phosphorylation of mTOR decreased. In conclusion, cyanate could induce oxidative stress damage and lipid deposition by inhibiting Nrf2/HO-1 pathway, which was rescued by inhibitor of Nrf2.

Significantly different clinical features between hypertriglyceridemia and biliary acute pancreatitis: a retrospective study of 730 patients from a tertiary center

BACKGROUND

Unlike western world, gallstones and hypertriglyceridemia (HTG) are among the first two etiologies of acute pancreatitis (AP) in China. But yet, detailed differences in clinical features and outcomes between hypertriglyceridemia and biliary acute pancreatitis have not been well described.

METHODS

This retrospective study enrolled 730 acute pancreatitis patients from July 1, 2013 to October 1, 2016 in Jinling Hospital. The causes of the study patients were defined according to specific diagnostic criteria. The clinical features and outcomes of patients with hypertriglyceridemia acute pancreatitis (HTG-AP) and biliary acute pancreatitis (BAP) were compared in terms of general information, disease severity, laboratory data, system complications, local complications, and clinical outcome.

RESULTS

In the enrolled 730 AP patients, 305 (41.8%) were HTG-AP, and 425 (58.2%) were BAP. Compared to BAP, the HTG-AP patients were found to be younger, with higher body mass Index (BMI), and much higher proportion of diabetes, fatty liver and high fat diet. Besides that, HTG-AP patients had significantly higher C-reactive protein (CRP) (p<0.01) and creatinine (p = 0.031), together with more acute respiratory distress syndrome (ARDS) (p = 0.039), acute kidney injury (AKI) (p<0.001), deep venous thrombosis (p = 0.008) and multiple organ dysfunction syndrome (MODS) (p = 0.032) in systematic complications. As for local complications, HTG-AP patients had significantly less infected pancreatitis necrosis (p = 0.005). However, there was no difference in mortality, hospital duration and costs between the groups.

CONCLUSION

HTG-AP patients were younger, more male, having high fat diet and with higher BMI compared to BAP patients. The prevalence of AKI/ARDS/DVT/MODS in HTG-AP patients was higher than BAP patients, while BAP patients had a greater possibility in development of infected pancreatitis necrosis (IPN). According to the multivariate analysis, only the complication of AKI was independently related with the etiology of HTG, however, BMI contributes to AKI, ARDS and DVT.

Antihypercholesterolemic, antioxidant and renal protective effects of Mengkudu (Rubiaceae) fruit in nephropathy-induced albino rats

OBJECTIVE

To assess the modulatory impact of alcoholic extract of fruit of Mengkudu (AEFM, Morinda citrifolia L., Rubiaceae) on renal oxido-lipidemic stress in hypercholesterolemic albino rats.

METHODS

Twenty-four male albino rats were randomly divided into four groups with six rats in each group: group I as control, group II fed with hypercholesterolemic diet (HCD) for 45 days (4% cholesterol and 1% cholic acid), Group III rats fed with HCD for 45 days + AEFM (300 mg/kg body weight/day orally) for last 30 days and group IV normal rats fed AEFM alone. The blood was collected using ethylenediamine tetraacetic acid (EDTA) as an anticoagulant for various biochemical analysis, and excision of kidney was done for histological analysis.

RESULTS

The levels of total cholesterol (TC), triacylglycerol (TG), phospholipids (PLs), renal functional parameters and lipid peroxidation products were markedly mitigated in AEFM treated hypercholesterolemic rats (group III) compared to group I (P<0.01). Activities of both enzymic and non-enzymic free radical scavenging factors were significantly increased in group III compared to group I (P<0.01). In group III the mRNA levels of interstitial endothelial nitric oxide synthase (eNOS) and inducible nitric oxide synthase (iNOS) genes were obviously up-regulated (P<0.01) and down-regulated in (P<0.05) compared with group I. Histomorphological observations also exhibited similar as in group III AEFM commendably protects the renal tissues compared with group I (P<0.01).

CONCLUSION

AEFM can act as nephroprotective agent by attenuating the renal oxidative stress, lipid levels as well as regulating NOS level and by this means protects the kidney in hypercholesterolemic induced nephropathy experimental rats.

Ultraviolet light-C increases antioxidant capacity of the strawberry (Fragaria x ananassa) in vitro and in high-fat diet-induced obese rats

Flavonoids and polyphenols from the strawberry and other fruits have been proposed to reduce the oxidative stress produced by the obesity and her complications. Moreover, it has been proposed that irradiation with UV-C to strawberry may increase the antioxidant capacity of this fruit. The aim of the present study was to explore the effects of the UV-C on antioxidant capacity of strawberry in vitro and in vivo. Strawberry slices were irradiated with ultraviolet light-C (UV-C) at 1.2 W/m²/16.5 min; then, the power antioxidant was isolated from the nonirradiated and irradiated strawberry slices into an organic phase, which was lyophilized to finally producing a nonirradiated strawberry extract (NSE) and UV-irradiated strawberry extract (UViSE) powder. After the antioxidant capacity of both extracts were determined in vitro using the Trolox equivalent antioxidant capacity (TEAC) assay and in vivo using high-fat diet-induced obese rats. Our results demonstrated that irradiation with UV-C to strawberry slices increased the antioxidants content, which was corroborated in vitro, where the antioxidant capacity of UViSE was higher than the NSE. However, in obese rats, the reduction in the oxidative damage by the UViSE and NSE were similar in peripheral tissues. Interestingly, the UViSE was better than the NSE to reduce the oxidative damage in brain. In conclusion, UV-irradiation increases the antioxidants content of strawberry that is correlated with an increased antioxidant capacity in vitro, but in rats, this antioxidant capacity may be more effective in brain than in peripheral tissues.

Downregulation of kidney protective factors by inflammation: role of transcription factors and epigenetic mechanisms

Chronic kidney disease (CKD) is associated to an increased risk of death, CKD progression, and acute kidney injury (AKI) even from early stages, when glomerular filtration rate (GFR) is preserved. The link between early CKD and these risks is unclear, since there is no accumulation of uremic toxins. However, pathological albuminuria and kidney inflammation are frequent features of early CKD, and the production of kidney protective factors may be decreased. Indeed, Klotho expression is already decreased in CKD category G1 (normal GFR). Klotho has anti-aging and nephroprotective properties, and decreased Klotho levels may contribute to increase the risk of death, CKD progression, and AKI. In this review, we discuss the downregulation by mediators of inflammation of molecules with systemic and/or renal local protective functions, exemplified by Klotho and peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α), a transcription factor that promotes mitochondrial biogenesis. Cytokines such as TWEAK, TNF-α, or transforming growth factor -β1 produced locally during kidney injury or released from inflammatory sites at other organs may decrease kidney expression of Klotho and PGC-1α or lead to suboptimal recruitment of these nephroprotective proteins. Transcription factors (e.g., Smad3 and NF-κB) and epigenetic mechanisms (e.g., histone acetylation or methylation) contribute to downregulate the expression of Klotho and/or PGC-1α, while histone crotonylation promotes PGC-1α expression. NF-κBiz facilitates the repressive effect of NF-κB on Klotho expression. A detailed understanding of these mediators may contribute to the development of novel therapeutic approaches to prevent CKD progression and its negative impact on mortality and AKI.

Role of NADPH Oxidase in Metabolic Disease-Related Renal Injury: An Update

Metabolic syndrome has been linked to an increased risk of chronic kidney disease. The underlying pathogenesis of metabolic disease-related renal injury remains obscure. Accumulating evidence has shown that NADPH oxidase is a major source of intrarenal oxidative stress and is upregulated by metabolic factors leading to overproduction of ROS in podocytes, endothelial cells, and mesangial cells in glomeruli, which is closely associated with the initiation and progression of glomerular diseases. This review focuses on the role of NADPH oxidase-induced oxidative stress in the pathogenesis of metabolic disease-related renal injury. Understanding of the mechanism may help find potential therapeutic strategies.

Osteopontin deficiency reduces kidney damage from hypercholesterolemia in Apolipoprotein E-deficient mice

Hypercholesterolemia is a well-established risk factor for kidney injury, which can lead to chronic kidney disease (CKD). Osteopontin (OPN) has been implicated in the pathology of several renal conditions. This study was to evaluate the effects of OPN on hypercholesterolemia induced renal dysfunction. Eight-week-old male mice were divided into 4 groups: apolipoprotein E knockout (ApoE^−/−) and ApoE/OPN knockout (ApoE^−/−/OPN^−/−) mice fed a normal diet (ND) or high cholesterol diet (HD). After 4 weeks, Periodic acid-Schiff (PAS) and oil red O staining revealed excessive lipid deposition in the glomeruli of ApoE^−/−HD mice, however, significantly suppressed in ApoE^−/−/OPN^−/−HD mice. Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) expression was lower in the glomeruli of ApoE^−/−/OPN^−/−HD mice than ApoE^−/−HD mice. In vitro study, primary mesangial cells were incubated with recombinant mouse OPN (rmOPN). RmOPN induced LOX-1 mRNA and protein expression in primary mesangial cells. Pre-treatment with an ERK inhibitor suppressed the LOX-1 gene expression induced by rmOPN. These results indicate that OPN contributes to kidney damage in hypercholesterolemia and suggest that inhibition of OPN may provide a potential therapeutic target for the prevention of hypercholesterolemia.

Sesamin Ameliorates High-Fat Diet-Induced Dyslipidemia and Kidney Injury by Reducing Oxidative Stress

The study explored the protective effect of sesamin against lipid-induced renal injury and hyperlipidemia in a rat model. An animal model of hyperlipidemia was established in Sprague-Dawley rats. Fifty-five adult Sprague-Dawley rats were divided into five groups. The control group was fed a standard diet, while the other four groups were fed a high-fat diet for 5 weeks to induce hyperlipidemia. Three groups received oral sesamin in doses of 40, 80, or 160 mg/(kg·day). Seven weeks later, the blood lipids, renal function, antioxidant enzyme activities, and hyperoxide levels in kidney tissues were measured. The renal pathological changes and expression levels of collagen type IV (Col-IV) and α-smooth muscle actin (α-SMA) were analyzed. The administration of sesamin improved the serum total cholesterol, triglyceride, low-density lipoprotein cholesterol, apolipoprotein-B, oxidized-low-density lipoprotein, and serum creatinine levels in hyperlipidemic rats, while it increased the high-density lipoprotein cholesterol and apolipoprotein-A levels. Sesamin reduced the excretion of 24-h urinary protein and urinary albumin and downregulated α-SMA and Col-IV expression. Moreover, sesamin ameliorated the superoxide dismutase activity and reduced malondialdehyde levels in kidney tissue. Sesamin could mediate lipid metabolism and ameliorate renal injury caused by lipid metabolism disorders in a rat model of hyperlipidemia.

A Long-Term High-Fat/High-Sucrose Diet Promotes Kidney Lipid Deposition and Causes Apoptosis and Glomerular Hypertrophy in Bama Minipigs

Metabolic syndrome can induce chronic renal injury in humans. In the present study, Bama minipigs were fed a high-fat/high-sucrose diet (HFHSD) for 23 months, which caused them to develop the pathological characteristics of metabolic syndrome, including obesity, hyperinsulinemia, and hyperlipidemia, and resulted in kidney tissue damage. In the HFHSD group, the ratio of the glomus areas to the glomerulus area and the glomerular density inside the renal cortex both decreased. Lipid deposition in the renal tubules was detected in the HFHSD group, and up-regulated expression levels of SREBP-1, FABP3 and LEPR promoted lipid deposition. The decreased levels of SOD, T-AOC and GSH-PX indicated that the antioxidant capacity of the renal tissues was diminished in the HFHSD group compared with MDA, which increased. The renal tissue in the HFHSD group exhibited clear signs of inflammation as well as significantly elevated expression of key genes associated with inflammation, including tumor necrosis factor-α (TNF-α) and macrophage migration inhibitory factor (MIF), compared with the control group. The tubular epithelial cells in the HFHSD group displayed significantly greater numbers of apoptotic cells, and the expression of proliferating cell nuclear antigen (PCNA) in the renal tubules decreased. Caspase-3 expression increased significantly, and the transcription factor nuclear factor κB (NF-κB) was activated and translocated into the nucleus. In conclusion, long-term HFHSDs cause metabolic syndrome and chronic renal tissue injury in Bama minipigs. These findings provide a foundation for further studies investigating metabolic syndrome and nephropathy.

Investigation into the antioxidant role of arginine in the treatment and the protection for intralipid-induced non-alcoholic steatohepatitis

Background

This study investigated the possible roles of arginine (Arg) in ameliorating oxidative damage of intralipid (IL)-induced steatohepatitis (NASH).

Methods

NASH was induced in Sprague-Dawley rats by intravenous administration of 20 % IL for three weeks and then rats were pre- and post-treated with intraperitoneal injection of Arg for two weeks. Several biochemical parameters (blood and hepatic lipid peroxidation, glutathione, glutathione peroxidase and superoxide dismutase, hepatic cytochrome P450 2El monooxygenase (CYP2E1), nitric oxide (NO), endothelial nitric oxide synthase (eNOS) and tumor necrosis factor-α “TNF-α”) and liver histopathology were detected for rat groups.

Results

The administration of Arg either before or after IL significantly ameliorated uncontrolled elevation of TBARS content, CYP2E1 activity (0.32 ± 0.01 or 0.3 ± 0.02 IU/mg) and TNF-α level. These effects were associated with a significant increase in the levels of glutathione, activities of antioxidant enzymes, NO level (1.649 ± 0.047 or 1.957 ± 0.073 μmol/g) and activity of hepatic eNOS (0.05 ± 0.002 or 0.056 ± 0.002 IU/mg) compared to the IL-treated rats. Moreover, the injection of Arg in NASH-induced rats showed normal hepatocytes, no steatosis and no bile duct proliferation but mild inflammation in the group which received IL after Arg.

Conclusions

These results proved that pre- and post-treatment with Arg blocked oxidative stress-induced NASH by inhibiting CYP2E1 activity, decreasing TNF- α level and restoration activities of eNOS and antioxidant enzymes as well as glutathione level. This antioxidant effect of Arg leads to reverse signs of liver pathology of NASH with amelioration of liver and kidney functions.

Prevention of cardiac hypertrophy by the use of a glycosphingolipid synthesis inhibitor in ApoE-/- mice

ApoE-/- mice fed a high fat and high cholesterol (HFHC) diet (20% fat and 1.25% cholesterol) from 12 weeks of age to 36 weeks revealed an age-dependent increase in the left ventricular mass (LV mass) and decline in fractional shortening (FS%), which worsened with HFHC diet. These traits are indicative of maladaptive pathological cardiac hypertrophy and dysfunction. This was accompanied by loading of glycosphingolipids and increased gene expression of ANP, BNP in myocardial tissue. Masson's trichrome staining revealed a significant increase in cardiomyocyte size and fibrosis. In contrast, treatment with 5 and 10 μM D-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol (D-PDMP), an inhibitor of glucosylceramide synthase and lactosylceramide synthase, dose-dependently decreased the load of glycosphingolipids and preserved fractional shortening and maintained left ventricular mass to normal 12-week-old control levels over a 6 month treatment period. Our mechanistic studies showed that D-PDMP inhibited cardiac hypertrophy by inhibiting the phosphorylation of mitogen-activated protein kinase (MAPK). We propose that associating increased glycosphingolipid synthesis with cardiac hypertrophy could serve as a novel approach to prevent this phenotype in experimental animal models of diet -induced atherosclerotic heart disease.

Hypertriglyceridemia is a risk factor for acute kidney injury in the early phase of acute pancreatitis

OBJECTIVE

The aim of this study was to investigate the risk factors for acute kidney injury (AKI) in patients with acute pancreatitis (AP).

METHODS

Patients with AP were retrospectively divided into AKI group and non-AKI group. To investigate the risk factors for AKI, logistic regression analysis was performed with demography, etiologies, and comorbidities. Mortalities of patients with different body mass indexes were compared.

RESULTS

There were 43 patients with AKI and 202 patients without AKI. The risk factor for AKI in AP was hypertriglyceridemia (odds ratio, 2.964; 95% confidence interval, 1.485-5.915; P = 0.007). Forty-two patients developed AKI within the first 48 hours. The mortalities of normal weight, overweight, and obese groups in patients with AKI were 16.7%, 17.4%, and 62.5%, respectively. All the 4 patients who died in the non-AKI group were of normal weight.

CONCLUSIONS

Hypertriglyceridemia is an independent risk factor for AKI in the early phase of AP. Obesity does not increase mortality of patients without AKI. We hypothesize that the role of pancreatic enzymes on triglyceride accumulated in renal may be an explanation for AKI in the early phase of AP.

Nephroprotective potential of Bacopa monniera on hypercholesterolemia induced nephropathy via the NO signaling pathway

CONTEXT

Bacopa monniera L. (Scrophulariaceae) is used as a traditional medicine in India for various ailments such as epilepsy, mental disorders, and also as a cardio-tonic. However, its nephroprotective role is still unknown.

OBJECTIVE

The present study assesses the modulatory impact of the alcoholic (ethanol) extract of Bacopa monniera (AEBM) on renal oxido-lipidemic stress in hypercholesterolemic rats.

MATERIALS AND METHODS

B. monniera (1 kg) was extracted with 90% ethanol, filtered, and dried (52 g). Group-I rats as control, Group-II rats fed with a hypercholesterolemic diet (HCD) for 45 d [4% cholesterol and 1% cholic acid], Group-III rats fed with HCD for 45 d + AEBM (40 mg/kg, body weight) for last 30 d, and Group-IV AEBM alone rats. Blood and kidney were removed to analyze lipid, antioxidant status, and histological analysis.

RESULT

The levels of total cholesterol (TC), triacylglycerol (TG), phospholipids (PLs), renal functional parameters (urea, creatinine, and uric acid), and lipid peroxidation (LPO) products were significantly attenuated (p < 0.01) in AEBM-treated hypercholesterolemic rats. Activities of both enzymic (superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione-S-transferase (GST), and glutathione reductase (GR)) and non-enzymic antioxidant (GSH, Vit-C, and Vit-E) were significantly increased (p < 0.01), on supplementation with AEBM. Administration with AEBM the mRNA levels of eNOS and iNOS genes was significantly up-regulated and down-regulated (p < 0.01). Histomorphological observations also evidenced that AEBM effectively protects the kidney from hypercholesterolemia-mediated oxido-lipidemic damage.

DISCUSSION AND CONCLUSION

From this study, we hypothesized that AEBM can act as renoprotective agent by attenuating the renal oxido-lipidemic stress via regulating NOS level and thereby protects the nephron in hypercholesterolemic rats.

Hepatoprotective and antioxidant activity of N-Trisaccharide in different experimental rats

OBJECTIVES

To investigate the hepatoprotective, antioxidant and antihyperlipidemic effect of N-Trisaccharide isolated from Cucumis prophetarum (L.) on different experimental rats.

METHODS

N-Trisaccharide (25 and 50 mg/kg.b.w), silymarin (25 mg/kg) and glibenclamide (25 mg/kg) was orally administered once daily for 28 days and toxicity evaluation studies were carried out. Liver damage was assessed by determining DNA damage, serum enzyme activities and hepatic histopathology of carbon tetrachloride (CCl4) induced hepatic injury in rats. Enzymatic and non enzymatic antioxidant levels in liver and kidney were determined and biochemical parameters such as, serum lipid profile, renal function markers were estimated in type 2 diabetic rats.

RESULTS

DNA fragmentation analysis revealed the protective effect of N-Trisaccharide on liver DNA damage. Histopathological studies indicated that CCl4-induced liver injury was less severe in N-Trisaccharide (25 and 50mg/kg) treated group. Given at the above doses conferred significant protection against the hepatotoxic actions of CCl4 in rats, reducing serum markers like SGOT, SGPT, ALP, creatinine and urea levels back to near normal (p<0.05) compared to untreated rats. In diabetic rats, N-Trisaccharide treatment significantly reversed abnormal status of enzymatic and non-enzymatic antioxidants levels to near normal. Also, serum lipids such as TG, TC, LDL-C and VLDL-C levels were significantly (p<0.05) reduced compared to diabetic untreated rats.

CONCLUSION

Present study results confirm that N-Trisaccharide possesses significant antihyperlipidemic, antioxidant and hepatoprotective properties.

Inhibition of myeloperoxidase activity by the alkaloids of Peganum harmala L. (Zygophyllaceae)

ETHNOPHARMACOLOGICAL RELEVANCE

Seeds and aerial parts of Peganum harmala L. are widely used in Algeria as anti-inflammatory remedies. Evaluation of Peganum harmala total alkaloids extracts and pure β-carboline compounds as an anti-inflammatory treatment by the inhibition of an enzyme key of inflammatory, myeloperoxidase (MPO) and HPLC quantification of the alkaloids from the different parts of plant.

MATERIALS AND METHODS

MPO inhibition was tested using taurine chloramine test. The inhibition of LDL oxidation induced by MPO was carried out. The molecular docking analysis of Peganum harmala alkaloids on MPO was performed using the Glide XP docking protocol and scoring function and the redox potential of alkaloids was determined using an Epsilon potentiostat. The concentration of harmala alkaloids was determined using HPLC analysis.

RESULTS

The HPLC profiling of the active total alkaloids indicates that β-carboline e.g. harmine, harmaline, harmane, harmol and harmalol are major components. As β-carbolines resemble tryptamine, of which derivatives are efficient inhibitors of MPO, the harmala alkaloids were tested for their activity on this enzyme. Total alkaloids of the seeds and of the aerial parts strongly inhibited MPO at 20µg/mL (97±5% and 43±4%, respectively) whereas, at the same concentration, those of the roots showed very low inhibition (15±6%). Harmine, harmaline and harmane demonstrated a significant inhibition of MPO at IC50 of 0.26, 0.08 and 0.72µM respectively. These alkaloids exerted a similar inhibition effects on MPO-induced LDL oxidation. Molecular docking analysis of Peganum harmala alkaloids on MPO showed that all active Peganum harmala alkaloids have a high affinity on the active site of MPO (predicted free energies of binding up to -3.1kcal/mol). Measurement of redox potentials versus the normal hydrogen electrode clearly differentiated (i) the high MPO inhibitory activity of harmine, harmaline and harmane (+1014, 1014 and 1003mV, respectively); and (ii) the low activity of harmalol and harmol (+629/778 and 532/644mV, respectively). A reverse phase HPLC method has been developed to determine simultaneously five alkaloids of Peganum harmala. Seeds contained all five β-carboline derivatives with the main active alkaloids, harmaline and harmine, being up to 3.8% and 2.9%, respectively. Up to 3.2% of harmine was determined in the roots. The four β-carboline derivatives, harmine, harmaline, harmane and harmalol were identified in the aerial parts. The highest inhibitory effect observed in seeds and the moderate effect of aerial parts could be explained by their harmine and harmaline content. In contrast, the very weak inhibition of the root extract, despite the presence of harmine, may tentatively be explained by the high concentration of harmol which can reduce Compound II of MPO to the native form.

CONCLUSION

The inhibition of MPO by Peganum harmala β-carboline alkaloids, herein reported for the first time, may explain the anti-inflammatory effect traditionally attributed to its herbal medicine.

Hyperlipidemia-associated renal damage decreases Klotho expression in kidneys from ApoE knockout mice

Background

Klotho is a renal protein with anti-aging properties that is downregulated in conditions related to kidney injury. Hyperlipidemia accelerates the progression of renal damage, but the mechanisms of the deleterious effects of hyperlipidemia remain unclear.

Methods

We evaluated whether hyperlipidemia modulates Klotho expression in kidneys from C57BL/6 and hyperlipidemic apolipoprotein E knockout (ApoE KO) mice fed with a normal chow diet (ND) or a Western-type high cholesterol-fat diet (HC) for 5 to 10 weeks, respectively.

Results

In ApoE KO mice, the HC diet increased serum and renal cholesterol levels, kidney injury severity, kidney macrophage infiltration and inflammatory chemokine expression. A significant reduction in Klotho mRNA and protein expression was observed in kidneys from hypercholesteromic ApoE KO mice fed a HC diet as compared with controls, both at 5 and 10 weeks. In order to study the mechanism involved in Klotho down-regulation, murine tubular epithelial cells were treated with ox-LDL. Oxidized-LDL were effectively uptaken by tubular cells and decreased both Klotho mRNA and protein expression in a time- and dose-dependent manner in these cells. Finally, NF-κB and ERK inhibitors prevented ox-LDL-induced Klotho downregulation.

Conclusion

Our results suggest that hyperlipidemia-associated kidney injury decreases renal expression of Klotho. Therefore, Klotho could be a key element explaining the relationship between hyperlipidemia and aging with renal disease.

Vitamin E and regression of hypercholesterolemia-induced oxidative stress in kidney

Hypercholesterolemia (HC) is an independent risk factor for the onset and progression of renal disease. HC induces oxidative stress (OS) in the kidney; Vitamin E (Vit.E), an antioxidant, slows the progression of OS in the kidney. This study was to investigate if Vit.E regresses the HC-induced OS, and the regression is associated with an increase in the antioxidant reserve (AR). The studies were carried out in four groups of rabbits. The kidneys were removed under anesthesia. OS and AR in the renal tissue were assessed by measuring malondialdetyde (MDA) and chemiluminescent (CL) activity, respectively. High-cholesterol diet elevated the serum total cholesterol (TC), and the regular diet with or without Vit.E following a high-cholesterol diet reduced the serum TC to control levels. HC increased the MDA levels of kidney by 5.54-fold compared to control. The MDA contents of the kidneys in groups on regular diet with or without Vit.E were, respectively, 56 and 53 % lower than the control group. The CL activity in the control group was 12.15 ± 0.73 × 10(6) RLU/mg protein. The CL activity in HC group was 45.26 % lower than that in control, indicating an increase in AR. The regular diet with or without Vit.E following high-cholesterol diet normalized the CL activity/AR. In conclusion, HC increases OS in the kidney; reduction of serum cholesterol by regular diet regresses the renal OS but Vit.E does not regress HC-induced OS in kidney.

Dyslipoproteinemia and impairment of renal function in diabetic kidney disease: an analysis of animal studies, observational studies, and clinical trials

Dyslipoproteinemia is highly prevalent in diabetes, chronic kidney disease, and diabetic kidney disease (DKD). Both diabetes and chronic kidney disease (CKD) are associated with hypertriglyceridemia, lower high-density lipoprotein, and higher small, dense low-density lipoprotein. A number of observational studies have reported that dyslipidemia may be associated with albuminuria, renal function impairment, and end-stage renal disease (ESRD) in the general population, and especially in CKD and DKD patients. Diabetic glomerulopathy and the related albuminuria are the main manifestations of DKD. Numerous animal studies support the finding that glomerular atherosclerosis is the main mechanism of glomerulosclerosis in CKD and DKD. Some randomized, controlled trials suggest the use of statins for the prevention of albuminuria and renal function impairment in CKD and DKD patients. However, a large clinical study, the Study of Heart and Renal Protection (SHARP), does not support that statins could reduce ESRD in CKD. In this article, we analyze the complex association of dyslipoproteinemia with DKD and deduce its relevance from animal studies, observational studies, and clinical trials. We show that special subgroups could benefit from the statin treatment.

Lipid droplet accumulation is associated with an increase in hyperglycemia-induced renal damage: prevention by liver X receptors

Dyslipidemia is a frequent component of the metabolic disorder of diabetic patients contributing to organ damage. Herein, in low-density lipoprotein receptor-deficient hyperlipidemic and streptozotozin-induced diabetic mice, hyperglycemia and hyperlipidemia acted reciprocally, accentuating renal injury and altering renal function. In hyperglycemic-hyperlipidemic kidneys, the accumulation of Tip47-positive lipid droplets in glomeruli, tubular epithelia, and macrophages was accompanied by the concomitant presence of the oxidative stress markers xanthine oxidoreductase and nitrotyrosine, findings that could also be evidenced in renal biopsy samples of diabetic patients. As liver X receptors (LXRα,β) regulate genes linked to lipid and carbohydrate homeostasis and inhibit inflammatory gene expression in macrophages, the effects of systemic and macrophage-specific LXR activation were analyzed on renal damage in hyperlipidemic-hyperglycemic mice. LXR stimulation by GW3965 up-regulated genes involved in cholesterol efflux and down-regulated proinflammatory/profibrotic cytokines, inhibiting the pathomorphology of diabetic nephropathy, renal lipid accumulation, and improving renal function. Xanthine oxidoreductase and nitrotyrosine levels were reduced. In macrophages, GW3965 or LXRα overexpression significantly suppressed glycated or acetylated low-density lipoprotein-induced cytokines and reactive oxygen species. Specifically, in mice, transgenic expression of LXRα in macrophages significantly ameliorated hyperlipidemic-hyperglycemic nephropathy. The results demonstrate the presence of lipid droplet-induced oxidative mechanisms and the pathophysiologic role of macrophages in diabetic kidneys and indicate the potent regulatory role of LXRs in preventing renal damage in diabetes.

Protective effect of dietary flavonoid quercetin against lipemic-oxidative hepatic injury in hypercholesterolemic rats

CONTEXT

Quercetin, a dietary-derived flavonoid, is ubiquitous in fruits and vegetables and plays important roles in human health by virtue of its antioxidant activity.

OBJECTIVE

This study was conducted to investigate the possible modulatory effect of quercetin against hepatic lipemic-oxidative injury in rats fed with a high cholesterol diet (HCD), and to highlight the underlying mechanisms of such effect.

MATERIALS AND METHODS

Different groups of male Sprague-Dawley rats were used; one group was treated by gavage with HCD cocktail (1 mL/100 g) whereas another group was orally administered HCD-enriched with quercetin (15 mg/kg). Corresponding control animals were also used.

RESULTS

Quercetin administration significantly decreased liver triglycerides (24%), liver total cholesterol (TC) (22%), serum TC (20%), serum low-density lipoprotein cholesterol (31%), and duplicated serum high-density lipoprotein cholesterol (HDL-C). This study also revealed that quercetin administration significantly reduced the activity of serum alanine aminotransferase (41%), aspartate aminotransferase (51%), and γ-glutamyl transpeptidase (G-GT) (35%). Significant inhibition of thiobarbituric acid-reacting substances (40%), together with a valuable enhancement of reduced glutathione (GSH) content (53%) in the liver homogenates, was observed. In addition, quercetin-treated hypercholesterolemic animals exhibited a reasonable improvement of hepatic antioxidant enzymes. Moreover, serum and liver content of nitric oxide (NO) were markedly decreased in this model (26 and 25%, respectively), and were almost normalized following quercetin administration.

DISCUSSION AND CONCLUSION

These data revealed that quercetin has the ability to ameliorate HCD-induced lipemic-oxidative injury in rat liver possibly through its antioxidant potential and/or increased NO bioavailability.

Vitamin E slows the progression of hypercholesterolemia-induced oxidative stress in heart, liver and kidney

Vitamin E suppresses the hypercholesterolemia-induced oxidative stress in the heart. The objectives were to investigate if: (a) hypercholesterolemia-induced oxidative stress is similar in heart, liver, and kidney, and is dependent upon duration of hypercholesterolemia; and (b) vitamin E slows the progression of oxidative stress in these organs. The rabbits were assigned to 4 groups: I, regular diet (2 months); II, 0.25 % cholesterol diet (2 months); III, 0.25 % cholesterol diet (4 months); and IV, 0.25 % cholesterol diet (2 months) followed by 0.25 % cholesterol diet plus vitamin E (2 months). Blood samples were collected before and at the end of protocol for the measurement of total cholesterol (TC). Hearts, livers, and kidneys were removed at the end of the protocol under anesthesia for the measurement of oxidative parameters, malondialdehyde (MDA), and chemiluminescence (CL). The basal MDA levels in the heart, liver, and kidney of rabbits in Group I were similar, but increased to 14.65-, 3.18-, and 10.35-fold, respectively, with hypercholesterolemia. The increases in MDA levels were dependent upon the duration of hypercholesterolemia. Vitamin E did not alter the TC levels, but reduced the MDA levels in all organs. Hypercholesterolemia and vitamin E had variable effects on CL activity. In conclusion, (i) hypercholesterolemia induces oxidative stress in heart, liver, and kidney, the heart being the most and the liver the least susceptible to oxidative stress; (ii) oxidative stress is positively associated with duration of hypercholesterolemia; and (iii) vitamin E slows the progression of oxidative stress in these organs.

Gender difference following high cholesterol diet induced renal injury and the protective role of rutin and ascorbic acid combination in Wistar albino rats

Background

An increased interest is given to the impact of high fat diet on health worldwide. Abnormalities in lipid metabolism induced by high cholesterol diet (HCD) were reported to exacerbate renal diseases via oxidative stress pathways. Rutin and ascorbic acid showed a protective role against oxidative stress-mediated diseases. Furthermore, both lipid metabolism and tissue response to oxidative stress damage was found to vary according to animal gender. Thus, the objective of this work was to examine possible gender-related differences and the possible protective effects of rutin and ascorbic acid supplementation on high cholesterol diet induced nephrotoxicity.

Methods

96 young male and female Wistar albino rats were used. HCD supplemented animals were treated with rutin alone or in combination with ascorbic acid for 6 weeks. Creatinine plasma level was estimated. Furthermore, kidney levels of nucleic acids, total protein, malondialdehyde (MDA), reduced glutathione (GSH), total cholesterol, and triglycerides were determined. Finally, kidney tissues were used for histopathological examination.

Results

HCD supplementation decreased kidney level of nucleic acids, which was more prominent in female animals. Both vitamin combination significantly attenuated HCD induced decrease in nucleic acids. Moreover, kidney level of MDA was significantly altered by HCD in both genders, which was inhibited by rutin and ascorbic acid alone or in combination in male groups and by both vitamins in female groups. There was a reduction in kidney level of GSH by HCD, especially in male groups, which was attenuated by rutin and ascorbic acid combination. Kidney levels of total cholesterol and triglycerides were significantly increased by HCD supplementation in both genders. Coadministration with rutin and/or ascorbic acid protected from such increase, which was more obvious in both vitamins combination. Histopathological investigation supported vitamins protective effect, which was more prominent in male vitamins combination group.

Conclusions

HCD-induced renal injury in female was higher than in male animals, suggesting a better anti-oxidative stress defense response in male's kidney. Moreover, the antioxidant and reno-protective effects of rutin and ascorbic acid were augmented following their combination.

Suppressive effects of continuous low-dose-rate γ irradiation on diabetic nephropathy in type II diabetes mellitus model mice

It has been proposed that the development of diabetic nephropathy is caused in large part by oxidative stress. We previously showed that continuous exposure of mice to low-dose-rate γ radiation enhances antioxidant activity. Here, we studied the ameliorative effect of continuous whole-body irradiation with low-dose-rate γ rays on diabetic nephropathy. Ten-week-old female db/db mice, an experimental model for type II diabetes, were irradiated with low-dose-rate γ rays from 10 weeks of age throughout their lives. Nephropathy was studied by histological observation and biochemical analysis of serum and urine. Antioxidant activities in kidneys were determined biochemically. Continuous low-dose-rate γ radiation significantly increases life span in db/db mice. Three of 24 irradiated mice were free of glucosuria after 80 weeks of irradiation. Histological studies of kidney suggest that low-dose irradiation increases the number of normal capillaries in glomeruli. Antioxidant activities of superoxide dismutase, catalase and glutathione are significantly increased in kidneys of irradiated db/db mice. Continuous low-dose-rate γ irradiation ameliorates diabetic nephropathy and increases life span in db/db mice through the activation of renal antioxidants. These findings have noteworthy implications for radiation risk estimation of non-cancer diseases as well as for the clinical application of low-dose-rate γ radiation for diabetes treatment.

Role of LOX-1 and ROS in oxidized low-density lipoprotein induced epithelial-mesenchymal transition of NRK52E

Background

To investigate the effect of oxidized low density lipoprotein receptor-1 (LOX-1) on tubular epithelial-mesenchymal transition (TEMT) induced by oxidized low-density lipoprotein (ox-LDL) and its mechanism.

Methods

NRK-52E cells were incubated with ox-LDL (0, 25, 50, and 100 μg/ml) for 24 hours or pre-treated with the chemical inhibitor of the LOX-1 receptor polyinosinic acid (poly I) and carrageenan or the antioxidant N-acetyl-L-cysteine (NAC), the cells were then exposed to 50 μg/ml of ox-LDL.The expression of LOX-I, E-cadherin, α-smooth muscle actin (α-SMA) and reactive oxygen species (ROS) were analyzed by real-time PCR, western blotting analysis, immunofluorescence and confocal laser scanning microscopy.

Results

Ox-LDL increased the expression of LOX-1 mRNA and protein in a dose-dependent manner from 0 to 100 μg/ml (P < 0.05). Following the increase in the LOX-1 protein level, the lipid intake, ROS generation and α-SMA expression increased; however, the E-cadherin level decreased. The pre-treatment with poly I or carrageenan or NAC significantly inhibited the LOX-1 expression, α-SMA expression, the lipid intake and ROS generation and reversed decrease of E-cadherin expression induced by ox-LDL. Meanwhile, the ROS generation were associated with a increase in the LOX-1 expression. The α-SMA expression was positively correlated with the ROS generation and LOX-1 expression, and the E-cadherin expression was negatively correlated with the ROS generation and LOX-1 expression.

Conclusions

LOX-1 and ROS may play a important role in epithelial-mesenchymal transition of NRK52E induced by OX-LDL.

Exercise therapy correlates with improving renal function through modifying lipid metabolism in patients with cardiovascular disease and chronic kidney disease

BACKGROUND

Patients with cardiovascular disease (CVD) and chronic kidney disease (CKD) are at high risk of cardiovascular mortality, thus therapies to improve renal function should be clinically investigated.

METHODS AND RESULTS

We divided consecutive patients with CVD and CKD (n=19) into exercise (n=10) and non-exercise (n=9) therapy groups. Exercise therapy for 12 weeks significantly improved the anaerobic metabolic threshold (AT-V O₂) and high-density lipoprotein cholesterol (HDL-C) levels, and reduced triglyceride levels. Exercise therapy also improved estimated glomerular filtration rate (eGFR). Change in eGFR correlated significantly and positively with change in AT-V O₂ and HDL-C, and negatively with change in triglyceride levels.

CONCLUSIONS

Exercise therapy correlates with improving renal function in CVD patients with CKD through modifying lipid metabolism. Exercise therapy could be an effective clinical strategy to improve renal function.

Protective effect of hydroxytyrosol and tyrosol against oxidative stress in kidney cells

Bioavailability studies in animals and humans fed with extravirgin olive oil demonstrated that hydroxytyrosol and tyrosol, the major simple phenolic compounds in extravirgin olive oil, are dose-dependently absorbed and excreted. Once absorbed, they undergo extensive metabolism; hydroxytyrosol and tyrosol concentrate mainly in the kidney, where they may exert an important role in the prevention of oxidative stress induced renal dysfunction. In this study we monitored the ability of hydroxytyrosol and tyrosol to protect renal cells (LLC-PK1) following oxidative damage induced by H2O2. Oxidative stress was evaluated by monitoring the changes of the membrane lipid fraction. Hydroxytyrosol exerted a significant antioxidant action, inhibiting the production of MDA, fatty acids hydroperoxides and 7-ketocholesterol, major oxidation products of unsaturated fatty acids and cholesterol, and thus protecting the cells from H2O2-induced damage. Tyrosol, instead, in this experimental model, did not exert any protective effect.