Severe hypertriglyceridemia and hypercholesterolemia accelerating renal injury: a novel model of type 1 diabetic hamsters induced by short-term high-fat / high-cholesterol diet and low-dose streptozotocin

Activation of NRF2 by epiberberine improves oxidative stress and insulin resistance in T2DM mice and IR-HepG2 cells in an AMPK dependent manner

ETHNOPHARMACOLOGICAL RELEVANCE

Phytochemical compounds offer a distinctive edge in diabetes management, attributed to their multifaceted target mechanisms and minimal toxicological profiles. Epiberberine (EPI), an alkaloid derived from plants of the Rhizoma Coptidis, has been reported to have antidiabetic effects. However, the underlying molecular mechanism of EPI are not fully elucidated.

AIM OF THE STUDY

This study explored the anti-diabetic effects of EPI and the role of the NRF2/AMPK signaling pathway in improving insulin resistance.

MATERIALS AND METHODS

We utilized two distinct models: in vivo, we employed mice with type 2 diabetes mellitus (T2DM) induced by high-fat diet (HFD) and streptozotocin (STZ) to conduct a range of assessments including measuring physical parameters, conducting biochemical analyses, examining histopathology, and performing Western blot tests. In parallel, in vitro experiments were carried out using insulin resistance (IR)-HepG2 cells, through which we conducted a CCK8 assay, glucose uptake tests, Western blot analyses, and flow cytometry studies.

RESULTS

In the EPI-treated group of T2DM mice, there was a significant reduction in hyperglycemia, IR, and hyperlipidemia, accompanied by beneficial changes in the liver and pancreas, as well as enhanced glucose uptake in IR-HepG2 cells. Herein, our finding also provided evidence that EPI could increase the expression of GLUT4 and activated the IRS-1/PI3K/AKT insulin signaling pathway to improve IR in vitro and in vivo. Moreover, EPI alleviated oxidative stress by enhancing SOD and GPX-px activity, decreasing reactive oxygen species (ROS) and malondialdehyde (MDA) content, and promoting nuclear factor (erythroid-derived 2)-like 2 (NRF2), total NRF2, NAD(P)H-quinone oxidoreductase (NQO1) and heme oxygenase-1 (HO-1) expression in the liver tissue of T2DM mice and IR-HepG2 cells. Furthermore, EPI decreased oxidative stress and improved IR, but these benefits were nullified by siNRF2 transfection. In particular, AMP-activated protein kinase (AMPK) deficiency by short-hairpin RNA (shRNA) partially reversed the effects of EPI on nuclear transcription, oxidative stress, and IR of NRF2 in IR-HepG2 cells.

CONCLUSIONS

Taken together, EPI activated NRF2-dependent AMPK cascade to protect T2DM from oxidative stress, thereby alleviating IR.

Animal models for induction of diabetes and its complications

Objectives

Animal models are widely used to develop newer drugs for treatment of diabetes and its complications. We conducted a systematic review to find various animal models to induce diabetes and also the suitable methods in various diabetic complications. With an emphasis on the animal models of diabetes induction, this review provides a basic overview of diabetes and its various types. It focused on the use of rats and mice for chemical, spontaneous, surgical, genetic, viral, and hormonal induction approaches.

Methods

All observations and research conducted on Diabetes and its complications published up to 18 May 2023 in PubMed, Web of Science, Scopus and Conchrane Library databases were included. Main outcome measures were reporting the induction of diabetes in experimental animals, the various animal models for diabetic complications including diabetic nephropathy, diabetic retinopathy, diabetic neuropathy and diabetic osteopathy. The quality of reporting of included articles and risk of bias were assessed.

Results

We reached various articles and found that rats and mice are the most frequently used animals for inducing diabetes. Chemical induction is the most commonly used followed by spontaneous and surgical methods. With slight modification various breeds and species are developed to study and induce specific complications on eyes, kidneys, neurons and bones.

Conclusions

Our review suggested that rats and mice are the most suitable animals. Furthermore, chemical induction is the method frequently used by experimenters. Moreover, high quality studies are required to find the suitable methods for diabetic complications.

N‑acetyl cysteine prevents ambient fine particulate matter‑potentiated atherosclerosis via inhibition of reactive oxygen species‑induced oxidized low density lipoprotein elevation and decreased circulating endothelial progenitor cell

Ambient fine particulate matter (PM) serves an important role in the development of cardiovascular disease, including atherosclerosis. Antioxidant N‑acetyl cysteine (NAC) has protective effects in the cardiovascular system. However, it is unknown if NAC prevents PM‑potentiated atherosclerosis in hyperlipidemia. Low‑density lipoprotein (LDL) receptor knockout mice were pretreated with 1 mg/ml NAC in drinking water for 1 week and continued to receive NAC, high‑fat diet and intranasal instillation of PM for 1 week or 6 months. Blood plasma was collected for lipid profile, oxidized (ox‑)LDL, blood reactive oxygen species (ROS) and inflammatory cytokine (TNF‑α, IL‑1β and IL‑6) measurement. Blood cells were harvested for endothelial progenitor cell (EPC) population and intracellular ROS analysis. Murine aorta was isolated for atherosclerotic plaque ratio calculation. NAC treatment maintained circulating EPC level and significantly decreased blood ox‑LDL and ROS, inflammatory cytokines, mononuclear and EPC intracellular ROS levels as well as aortic plaque ratio. NAC prevented PM‑potentiated atherosclerosis by inhibiting plasma ROS‑induced ox‑LDL elevation, mononuclear cell and EPC intracellular ROS‑induced circulating EPC reduction and inflammatory cytokine production.

Melatonin relieves diabetic complications and regenerates pancreatic beta cells by the reduction in NF-kB expression in streptozotocin induced diabetic rats Melatonin: anti-diabetic drug

Melatonin, a pleiotropic hormone, has many regulatory effects on the circadian and seasonal rhythms, sleep and body immune system. It is used in the treatment of blind circadian rhythm sleep disorders, delayed sleep phase and insomnia. It is a potent antioxidant, anti-inflammatory, free radical scavenger, helpful in fighting infectious disease and cancer treatment. Decreased level of circulating melatonin was associated with an increased blood glucose level, losing the anti-oxidant protection and anti-inflammatory responses. We aimed to evaluate the effect of melatonin administration, in streptozotocin (STZ) induced diabetic rats, on blood glucose level and pancreatic beta (β) cells. Diabetes mellitus was induced in Sprague dawley male rats by the intravenous (i.v) injection of 65 mg/kg of STZ. Diabetic rats received melatonin at a dose of 10 mg/kg daily for 8 weeks by oral routes. The results showed, after 8 weeks of melatonin administration, a reduction in: 1- fasting blood glucose (FBG) and fructosamine (FTA) levels, 2- kidney and liver function parameters, 3- levels of serum triglycerides, cholesterol and LDL-C, 4- malondialdehyde (MDA), 5- NF-κB expression in treated group, 6- pro-inflammatory cytokines (IL-1β and IL-12) and immunoglobulins (IgA, IgE and IgG). Furthermore, an elevation in insulin secretion was noticed in melatonin treated group that indicated β cells regeneration. Therefore, melatonin administration, in STZ induced diabetic rats; reduced hyperglycemia, hyperlipidemia and oxidative stress. Melatonin acted as an anti-inflammatory agent that reduced pro-inflammatory cytokines (IL-1β and IL-12) and oxidative stress biomarkers (MDA). Melatonin succeeded in protecting β cells under severe inflammatory situations, which was apparent by the regeneration of islets of Langerhans in treated diabetic rats. Moreover, these results can open a gate for diabetes management and treatment.

The Effect of Ilex × meserveae S. Y. Hu Extract and Its Fractions on Renal Morphology in Rats Fed with Normal and High-Cholesterol Diet

Therapeutic properties of Ilex species are widely used in natural medicine. Ilex × meserveae may become a potential substitute for Ilex paraguariensis (Yerba Mate). As a part of the preliminary safety verification of this European Ilex hybrid vs. Yerba Mate, an eight-week study concerning the impact of regular administration of leaves of both species on kidneys was conducted. The standard water infusion and three dominant fractions of Ilex × meserveae leaves’ constituents (polyphenols, saponins and less polar terpenoids) were separately tried on 96 male Wistar rats divided into 8-member groups. Animals were divided into two basic nutritional groups: the first one was rats fed standard feed and the second on was rats fed with high-cholesterol diet (20 g of cholesterol per kg of standard feed). Postmortem morphometric evaluation of stained kidney samples concerned the filtration barrier elements, which are crucial in proper diuresis. The results showed that saponins present in the hydroalcoholic dry extract (administered in a dose of 10 mg/kg of body weight/day) as well as in water infusions (1:20) from Ilex × meserveae and Ilex paraguariensis do not demonstrate nephrotoxicity but conversely, have a protective role on kidney status in animals fed with a normal diet and in a high-cholesterol diet.

Antidiabetic effect of olive leaf extract on streptozotocin-induced diabetes mellitus in experimental animals

Introduction

Background: recently, a relationship between diabetic complications and oxidative stress has been emphasized. There have been some studies showing the effect of olive leaf on hyperglycemia and diabetic complications due to its antioxidant properties. In many studies the effect of olive leaf on plasma total antioxidant level has been measured by different methods. Our study represents the first time it has been measured by a new method of total thiol disulfide homeostasis. Aim: chronic exposure to hyperglycemia and hyperlipidemia contributes to the pathogenesis of diabetic complications through oxidative stress mediators. Thiol is one of the most important antioxidant barriers in humans, and thiol disulfide homeostasis is a new oxidative stress marker. We aimed to investigate the effect of olive leaf extract (OLE) obtained from fresh leaves of Olea europaea, var oleaster on diabetic complications through their hypoglycemic and antioxidant effect in diabetic rats. Methods: twenty-eight Wistar albino rats aged 12-13 weeks were used in the study. The rats were divided into a control group (C), a diabetic control group (DC), a diabetic group treated with 200 mg/kg OLE (D+200), and a diabetic group treated with 400 mg/kg OLE (D+400), having 7 rats in each group. The treatment groups received OLE by the gavage method for 21 days. At the end of the study, all rats were sacrificed by cervical dislocation. Blood samples collected from the heart were centrifuged and glucose, total cholesterol, triglyceride, urea, uric acid, creatinine, alanine aminotransferase (ALT), aspartate aminotransferase (AST), lipid hydroperoxide (LOOH) level, and thiol-disulfide homeostasis were determined. The hemoglobin A1c (HbA1c) analysis was performed on complete blood. In addition, a tail flick test and hot plate modeling were performed to indicate pain perception loss. Results: it was observed that OLE had no effect on serum glucose and HbA1c levels. On the contrary, OLE reduced the levels of total cholesterol (p < 0.01), urea (p < 0.01) and hot plate latency (p < 0.01) in a significant manner. Also, OLE showed a tendency to reduce LOOH levels and to increase thiol levels in a dose-dependent manner (p > 0.05). Conclusion: OLE supplementation for 21 days, at the amounts used, cannot protect against hyperglycemia but may be protective against hypercholesterolemia and tissue damage as caused by diabetes mellitus in rats.

Dietary Indigenous Cinnamon (Cinnamomum osmophloeum) Leaf Powder Reduces Plasma Lipid in Hypercholesterolemia Hamsters

Indigenous cinnamon ( Cinnamomum osmophloeum Kaneh) is a native tree species in Taiwan and has been reported to have various bioactivities including insecticidal, larvicidal, and antimicrobial effects. The chemical finger print of C. osmophloeum is similar to that of commercial cinnamon species with lower coumarin content. The present study was aimed to investigate the antidyslipidemia effects of indigenous cinnamon ( Cinnamomum osmophloeum Kaneh) leaf powder (CoLP) on hypercholesterolemia hamsters. Hyperlipidemia was induced by high-cholesterol (HChol) diet for 4 weeks. Two percent and 5% CoLP, and gemfibrozil (positive control; 0.25%) were administered for 10 weeks following HChol diet. Control groups were fed with normal diet (ND) or ND+5% CoLP. Behavioral, physiological, and serum biochemical parameters were determined. We found that oral administration of CoLP for 10 weeks significantly reduced the HChol-induced increase of total cholesterol (TC), triglyceride, and low-density lipoprotein levels in plasma of hamsters. In addition, HChol-induced elevation of serum glutamic oxaloacetic transaminase and glutamic pyruvic transaminase levels was significantly reversed by CoLP in a dose-dependent manner, whereas blood urea nitrogen and creatinine levels were unaffected. Further standard diagnostic tests support that consumption of CoLP did not show any behavioral and morphological changes in hamsters. Furthermore, chemical composition analysis revealed that two new flavanol glycosides, kaempferol-3- O-α-l-rhamnopyranosyl-(1→2)-α-l-arabinofuranosyl-7- O-α-l-rhamnopyranoside (4) and kaempferol-3- O-β -d-apiofuranosyl-(1→2)-α-l-arabinofuranoside (5) along with 4 known flavonoid glycosides were identified in leaves of C. osmophloeum. Taken together, these results concluded that CoLP possessed strong antidyslipidemic effects. Therefore, C. osmophloeum leaves could be a safe food supplement for treating hypercholesterolemia.

Angiopoietin-like protein 3 markedly enhanced in the hyperlipidemia related proteinuria

BACKGROUND

Angiopoietin-like protein 3(ANGPTL3) is well acknowledged as a key regulator of lipid metabolism. Now, there have not been enough data to explain the mechanism of hyperlipidemia related proteinuria. In this study, we hoped to investigate the changes of Angiopoietin-like protein 3(ANGPTL3) levels in hyperlipidemia patients with different proteinuria levels.

METHODS

Seventy-one patients with hyperlipidemia were selected, who were hospitalized in Gansu Provincial People's Hospital from September 2016 to September 2017, and 20 healthy people in the physical examination center were selected. We combed through medical history and conducted clinical biochemical indicators of blood urea nitrogen (BUN), serum creatinine (SCr), 24 h urine protein quantitation (24hUPro), cholesterol (TC), triglyceride (TG), high density lipoprotein (HDL) and low detection of density lipoproteins (LDL-C). The concentration of serum ANGPTL3 was measured by ELISA.

RESULTS

1. Serum ANGPTL3 in patients with hyperlipidemia related proteinuria was higher than that in the control group, and the difference was statistically significant (p < 0.05); 2. 24hUPro and BMI (r = 0.321, P = 0.002), TC (r = 0.465, P = 0.000), TG (r = 0.281, P = 0.007), LDL (r = 0.478, P = 0.000) in patients with hyperlipidemia related proteinuria are positively correlated, suggesting that dyslipidemia is related to the occurrence of proteinuria; 3. BMI, TC, TG and LDL in patients with hyperlipidemia related proteinuria were positively correlated with serum ANGPTL3. 4. The 24hUPro of patients with hyperlipidemia related proteinuria was positively correlated with serum ANGPTL3 levels, and BUN and SCr were not associated with serum ANGPTL3 level. 5. There was no significant difference in TC, TG, BMI, 24hUPro and serum ANGPTL3 between the statin-treated and the untreated groups in patients with hyperlipidemia related proteinuria.

CONCLUSIONS

Angiopoietin-like protein 3 markedly enhanced in the hyperlipidemia related proteinuria.

Formononetin attenuates kidney damage in type 2 diabetic rats

AIM

Diabetic nephropathy is the commonly developed complication of vasculature in type 2 diabetic patients. Chronic hyperglycemia leads to nephropathy in diabetics because of the formation of excessive reactive oxygen species and advanced glycation end products which is reflected in the form of glomerulosclerosis, tubular atrophy and interstitial fibrosis. As per the various reports reduction in SIRT1 expression in kidney tissue is key factor in the development of nephropathy in diabetes because its reduction in tissue is linked with excessive formation of ROS. Formononetin is a polyphenolic compound reported for its effect on SIRT1 and ROS.

MAIN METHODS

Type 2 diabetes was induced in rats by diet modification using high fat diet for fifteen days prior to streptozotocin regimen (35 mg/kg, i.p.). Treatment of formononetin was started after confirmation of diabetes and continued for 16 weeks. Formononetin was administered orally to the diabetic animals at the dose of 10. 20 and 40 mg/kg.

KEY FINDINGS

Formononetin treatment for 16 week was able to control hyperglycemia and insulin resistance in diabetic animals. It has also been reduced triglyceride and cholesterol in blood. Formononetin treatment reduced blood concentration of creatinine, blood urea nitrogen and increased albumin concentration. Formononetin treatment also enhanced creatinine clearance in diabetic animals. Oxidative stress burden was also reduced significantly after formononetin treatment along with increased SIRT1 expression in kidney tissues of diabetic animals.

SIGNIFICANCE

Formononetin is a potential molecule which increases the expression of SIRT1 in kidney tissue of diabetic. Thus formononetin is an effective molecule to control nephropathy in type 2 diabetes mellitus.

Salix alba attenuated oxidative stress in the heart and kidney of hypercholesterolemic rabbits

OBJECTIVE

Oxidative stress plays a critical role in the development of hypercholesterolemia-induced complications. This study evaluated the effects of aspirin and Salix alba hydroethanolic extract on oxidative stress in the heart and kidney of hypercholesterolemic rabbits.

MATERIALS AND METHODS

The antioxidant activity, as well as total phenolic and salicin content of S. alba (Sa) extract were assessed by DPPH radical scavenging activity, Folin-Ciocalteu and HPLC methods, respectively. Animals were divided into two groups of control (fed with normal chow), and HD (fed with high cholesterol diet for 6 weeks). Then, hypercholesterolemic animals allocated to the following treatment groups: CHO (received HD), Sa extract (HD plus extract 60 and 120 mg/kg), and aspirin (HD plus aspirin 120 mg/kg) and received the treatments on a daily basis for 6 weeks. MDA, GSH, and nitrite concentrations as well as the activities of SOD and CAT were evaluated in cardiac and kidney tissues.

RESULTS

The scavenging activity, total phenolic content and salicin were 19.1 µg/ml (IC50), 153.75 ± 3.6 mg of gallic acid/g, and 18.03 µg/mg, respectively. In comparison to CHO group, MDA levels were diminished in Sa and ASA groups but GSH levels were improved. NO metabolites increased in the heart of Sa 120 mg/kg group and in the kidney of all Sa and ASA treated groups. SOD activity increased only in the heart of Sa groups and in the kidney of Sa and ASA groups. CAT activity increased in the heart and kidney tissues of all Sa and ASA treated groups.

CONCLUSION

The results showed S. alba extract improved redox homeostasis in heart and kidney tissues of hypercholesterolemic rabbits. The extract antioxidant property may be related to its phenolic content.

Hypolipidemic activity of P-methoxycinnamic diester (PCO-C) isolated from Copernicia prunífera against Triton WR-1339 and hyperlipidemic diet in mice

Carnauba wax is extracted from the leaves of the Copernicia prunífera and contains approximately 80% of esters in its composition. The purpose of the present study was evaluate the hypolipidemic effect of p-methoxycinnamic diesters (PCO-C) extracted from Copernicia prunífera in a model of acute and chronic dyslipidemia in mice. The levels of total cholesterol and triglycerides were significantly reduced plasma levels in PCO-C at the dose of 100mg/kg in a model of acute and chronic dyslipidemia. Histological studies showed that PCO-C has no hepatotoxic effect and reduces hepatic steatosis in animals that consumed hyperlipidemic ration. Thus, it was concluded that PCO-C isolated from Copernicia Prunifera was effective in reducing total cholesterol and triglyceride levels in both dyslipidemia induction models. The finding indicates that PCO-C might be beneficial in treatment of hyperlipidemia and atherosclerosis.

Antihyperglycemic effect of hesperetin, a citrus flavonoid, extenuates hyperglycemia and exploring the potential role in antioxidant and antihyperlipidemic in streptozotocin-induced diabetic rats

Diabetes is the major health problem in modern civilization which occurs due to inadequate metabolism of carbohydrate and lipid could cause tremendous changes in the metabolic activities of liver. In this study, we investigated the antihyperglycemic, antioxidant and antihyperlipidemic effects of hesperetin, a citrus flavonoid against streptozotocin (STZ)-induced experimental rats. To stimulate diabetes mellitus, rats were injected with STZ intraperitoneally at a single dose of 45mg/kg. STZ induced rats showed marked increase in the level of plasma glucose and significant reduction in the level of plasma insulin. The activities of carbohydrate metabolic enzymes, hepatic glycogen, lipid profiles, enzymic antioxidants in circulatory system and pancreas, hepatic and renal functional markers were explored. Supplementation with hesperetin (40mg/kg b.w) to STZ-induced experimental rats for 45days established a significant decline in plasma glucose and a marked improvement in plasma insulin and glycogen levels in STZ-induced rats. The altered activities of hepatic glucose metabolic enzymes, lipid profiles, enzymic antioxidants and serum biomarkers of liver and kidney toxicity were restored to almost normal. The acquired outcome were compared with glibenclamide (1mg/kg b.w), a standard oral hypoglycemic drug. Hesperetin treatment was found to be efficient in protecting the normal histological manifestation of hepatic, renal and insulin positive β-cells in STZ induced rats. On the basis of current experimental findings, we concluded that administration of hesperetin attenuates the hyperglycemia and dyslipidemia through ameliorating antioxidant competence in STZ-induced experimental rats.

Protective effect of the standardized extract of ginkgo biloba (EGb761) against hypertension with hypercholesterolemia-induced renal injury in rats: Insights in the underlying mechanisms

The potential protective role of the standardized leaf extract of ginkgo biloba (EGb761) on hypertension with hypercholesterolemia-induced renal injury was investigated in rats. Hypertension was induced by L-N(G)-nitroarginine methyl ester (L-NAME) and hypercholesterolemia was induced by feeding rats with a diet containing 1% cholesterol. In these animals repeated treatment with EGb761 produced a progressive reduction in the systolic, diastolic and mean arterial blood pressure (BP). EGb761 increased the progressive reduction in the systolic, diastolic and mean arterial BP induced by repeated administration of losartan with simvastatin. EGb761 corrected the compromised serum lipid profile and enhanced the effect of losartan with simvastatin on lipid profile. EGb761 protected against hypertension with hypercholesterolemia-induced renal injury as assessed by measurement of serum renal function markers and by histopathological examination. EGb761 enhanced the renoprotective effect of losartan with simvastatin in these rats. Concomitantly, hypertension with hypercholesterolemia-induced elevation of renal tissue malondialdehyde (MDA) and nitrite levels and reduction of intracellular reduced glutathione (GSH) level were inhibited by repeated treatment with EGb761. In addition, hypertension with hypercholesterolemia-induced increases in tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and interleukin-1β (IL-1β) levels in renal tissues were inhibited by treatment with EGb761. Also, EGb761 inhibited hypertension with hypercholesterolemia-induced decrease in endothelial nitric oxide synthase (eNOS) protein expression and increase in the protein expressions of inducible NO synthase (iNOS), TNF-α, IL-6 and IL-1β in the kidney tissues. Losartan with simvastatin produced similar effects on renal tissues oxidative stress, nitrite and inflammatory markers levels and on protein expressions of eNOS, iNOS, TNF-α, IL-6 and IL-1β. EGb761 enhanced losartan with simvastatin effects. These results indicate that EGb761 has the ability to protect against hypertension with hypercholesterolemia-induced renal injury. The ability of EGb761 to provide this renoprotective effect may positively correlate, besides its antihypertensive and antihypercholesterolemic effects, to its ability to suppress renal oxidative stress, nitrosative stress and inflammation.

Paternal High Fat Diet in Rats Leads to Renal Accumulation of Lipid and Tubular Changes in Adult Offspring

Along with diabetes and obesity, chronic kidney disease (CKD) is increasing across the globe. Although some data support an effect of maternal obesity on offspring kidney, the impact of paternal obesity is unknown; thus, we have studied the effect of paternal obesity prior to conception. Male Sprague Dawley rats were fed chow diet or high fat diet (HFD) for 13-14 weeks before mating with chow-fed females. Male offspring were weaned onto chow and killed at 27 weeks for renal gene expression and histology. Fathers on HFD were 30% heavier than Controls at mating. At 27 weeks of age offspring of obese fathers weighed 10% less; kidney triglyceride content was significantly increased (5.35 ± 0.84 vs. 2.99 ± 0.47 μg/mg, p < 0.05, n = 8 litters per group. Histological analysis of the kidney demonstrated signs of tubule damage, with significantly greater loss of brush border, and increased cell sloughing in offspring of obese compared to Control fathers. Acat1, involved in entry of fatty acid for beta-oxidation, was significantly upregulated, possibly to counteract increased triglyceride storage. However other genes involved in lipid metabolism, inflammation and kidney injury showed no changes. Paternal obesity was associated with renal triglyceride accumulation and histological changes in tubules, suggesting a mild renal insult in offspring, who may be at risk of developing CKD.

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.

Increased HDL Size and Enhanced Apo A-I Catabolic Rates Are Associated With Doxorubicin-Induced Proteinuria in New Zealand White Rabbits

The catabolism and structure of high-density lipoproteins (HDL) may be the determining factor of their atheroprotective properties. To better understand the role of the kidney in HDL catabolism, here we characterized HDL subclasses and the catabolic rates of apo A-I in a rabbit model of proteinuria. Proteinuria was induced by intravenous administration of doxorubicin in New Zealand white rabbits (n = 10). HDL size and HDL subclass lipids were assessed by electrophoresis of the isolated lipoproteins. The catabolic rate of HDL-apo A-I was evaluated by exogenous radiolabelling with iodine-131. Doxorubicin induced significant proteinuria after 4 weeks (4.47 ± 0.55 vs. 0.30 ± 0.02 g/L of protein in urine, P < 0.001) associated with increased uremia, creatininemia, and cardiotoxicity. Large HDL2b augmented significantly during proteinuria, whereas small HDL3b and HDL3c decreased compared to basal conditions. HDL2b, HDL2a, and HDL3a subclasses were enriched with triacylglycerols in proteinuric animals as determined by the triacylglycerol-to-phospholipid ratio; the cholesterol content in HDL subclasses remained unchanged. The fractional catabolic rate (FCR) of [(131)I]-apo A-I in the proteinuric rabbits was faster (FCR = 0.036 h(-1)) compared to control rabbits group (FCR = 0.026 h(-1), P < 0.05). Apo E increased and apo A-I decreased in HDL, whereas PON-1 activity increased in proteinuric rabbits. Proteinuria was associated with an increased number of large HDL2b particles and a decreased number of small HDL3b and 3c. Proteinuria was also connected to an alteration in HDL subclass lipids, apolipoprotein content of HDL, high paraoxonase-1 activity, and a rise in the fractional catabolic rate of the [(131)I]-apo A-I.