Oxidative Stress and Nuclear Factor κB (NF-κB) Increase Peritoneal Filtration and Contribute to Ascites Formation in Nephrotic Syndrome

Yue-bi-tang attenuates adriamycin-induced nephropathy edema through decreasing renal microvascular permeability via inhibition of the Cav-1/ eNOS pathway

Edema is one of the most typical symptoms of nephrotic syndrome. Increased vascular permeability makes a significant contribution to the progression of edema. Yue-bi-tang (YBT) is a traditional formula with excellent clinical efficacy in the treatment of edema. This study investigated the effect of YBT on renal microvascular hyperpermeability-induced edema in nephrotic syndrome and its mechanism. In our study, the content of target chemical components of YBT was identified using UHPLC-Q-Orbitrap HRMS analysis. A nephrotic syndrome model was replicated based on male Sprague-Dawley rats with Adriamycin (6.5 mg/kg) by tail vein injection. The rats were randomly divided into control, model, prednisone, and YBT (22.2 g/kg, 11.1 g/kg, and 6.6 g/kg) groups. After 14 d of treatment, the severity of renal microvascular permeability, edema, the degree of renal injury, and changes in the Cav-1/eNOS pathway were assessed. We found that YBT could regulate renal microvascular permeability, alleviate edema, and reduce renal function impairment. In the model group, the protein expression of Cav-1 was upregulated, whereas VE-cadherin was downregulated, accompanied by the suppression of p-eNOS expression and activation of the PI3K pathway. Meanwhile, an increased NO level in both serum and kidney tissues was observed, and the above situations were improved with YBT intervention. It thus indicates YBT exerts therapeutic effects on the edema of nephrotic syndrome, as it improves the hyperpermeability of renal microvasculature, and that YBT is engaged in the regulation of Cav-1/eNOS pathway-mediated endothelial function.

Rodent models to study sodium retention in experimental nephrotic syndrome

Sodium retention and edema are hallmarks of nephrotic syndrome (NS). Different experimental rodent models have been established for simulating NS, however, not all of them feature sodium retention which requires proteinuria to exceed a certain threshold. In rats, puromycin aminonucleoside nephrosis (PAN) is a classic NS model introduced in 1955 that was adopted as doxorubicin-induced nephropathy (DIN) in 129S1/SvImJ mice. In recent years, mice with inducible podocin deletion (Nphs2^Δipod ) or podocyte apoptosis (POD-ATTAC) have been developed. In these models, sodium retention is thought to be caused by activation of the epithelial sodium channel (ENaC) in the distal nephron through aberrantly filtered serine proteases or proteasuria. Strikingly, rodent NS models follow an identical chronological time course after the development of proteinuria featuring sodium retention within days and spontaneous reversal thereafter. In DIN and Nphs2^Δipod mice, inhibition of ENaC by amiloride or urinary serine protease activity by aprotinin prevents sodium retention, opening up new and promising therapeutic approaches that could be translated into the treatment of nephrotic patients. However, the essential serine protease(s) responsible for ENaC activation is (are) still unknown. With the use of nephrotic rodent models, there is the possibility that this (these) will be identified in the future. This review summarizes the various rodent models used to study experimental nephrotic syndrome and the insights gained from these models with regard to the pathophysiology of sodium retention.

Nephrotic Syndrome Complications - New and Old. Part 1

Nephrotic syndrome is a rare condition with an incidence of 2-7 cases/100.000 children per year and three new cases/100.000 adults per year. It occurs as a result of severe alteration of the glomerular filtration barrier of various causes, allowing proteins, mostly albumin, to be lost in the urine. Nephrotic syndrome complications are driven by the magnitude of either proteinuria or hypoalbuminemia, or both. Their frequency and severity vary with proteinuria and serum albumin level. Besides albumin, many other proteins are lost in urine. Therefore, nephrotic patients could have low levels of binding proteins for ions, vitamins, hormones, lipoproteins, coagulation factors. The liver tries to counterbalance these losses and will increase the unselective synthesis of all types of proteins. All of these changes will have different clinical consequences. The present paper aims to discuss the pathophysiological mechanism and new therapeutic recommendations for nephrotic syndrome edema and thromboembolic complications.

Catalase-Containing Silica Particles as Ultrasound-Based Hydrogen Peroxide Sensors to Determine Infected From Noninfected Fluid Collections in Humans

OBJECTIVE. Hydrogen peroxide (H₂O₂) plays a key role in neutrophil oxidative defense against infection. Catalase-containing silica nanoshells are nanoparticles that generate O₂ microbubbles imaged with ultrasound in the presence of elevated H₂O₂. We aimed to determine whether ultrasound-detectable O₂ microbubbles produced by catalase-containing silica nanoshells can determine whether fluid collections drained from patients are infected. SUBJECTS AND METHODS. During this HIPAA-compliant, institutional review board-approved study, 52 human fluid samples were collected from clinically required image-guided percutaneous drainage procedures. Catalase-containing silica nanoshells were added to the fluid samples during imaging in real time using a Sequoia-512 15L8-S linear transducer (Siemens Healthcare). Production of detectable microbubbles was graded subjectively as negative (noninfected) or positive (infected) with low, moderate, or high confidence by a single observer blinded to all clinical data. The truth standard was microbiology laboratory culture results. Performance characteristics including ROC curves were calculated. RESULTS. Microbubble detection to distinguish infected from noninfected fluids was 84% sensitive and 72% specific and offered negative and positive predictive values of 89% and 64%, respectively. The AUC was 0.79. Six of nine false-positive samples were peritoneal fluid collections that were all collected from patients with decompensated cirrhosis. CONCLUSION. The presence of elevated H₂O₂ indicated by microbubble formation in the presence of catalase-containing silica nanoshells is sensitive in distinguishing infected from noninfected fluids and offers a relatively high negative predictive value. False-positive cases may result from noninfectious oxidative stress. Catalase-containing silica nanoshells may constitute a novel point-of-care test performed at time of percutaneous drainage, potentially obviating placement of drains into otherwise sterile collections and minimizing risk of secondary infection or other complication.

Nephrotic Syndrome: Oedema Formation and Its Treatment With Diuretics

Oedema is a defining element of the nephrotic syndrome. Its' management varies considerably between clinicians, with no national or international clinical guidelines, and hence variable outcomes. Oedema may have serious sequelae such as immobility, skin breakdown and local or systemic infection. Treatment of nephrotic oedema is often of limited efficacy, with frequent side-effects and interactions with other pharmacotherapy. Here, we describe the current paradigms of oedema in nephrosis, including insights into emerging mechanisms such as the role of the abnormal activation of the epithelial sodium channel in the collecting duct. We then discuss the physiological basis for traditional and novel therapies for the treatment of nephrotic oedema. Despite being the cardinal symptom of nephrosis, few clinical studies guide clinicians to the rational use of therapy. This is reflected in the scarcity of publications in this field; it is time to undertake new clinical trials to direct clinical practice.

Renoprotective Effects of Antroquinonol in Rats with Nω-Nitro-l-Arginine Methyl Ester-Induced Hypertension

Endothelial dysfunction leads to elevation of blood pressure and vascular remodeling, which may result in tissue injuries. The aim of this study was to investigate the mechanisms and effects of antroquinonol on hypertension and related renal injuries. Rats were fed water containing 25 mg/kg/day N^ω-nitro-l-arginine methyl ester (L-NAME) to induce hypertension, and a diet with or without antroquinonol (20 or 40 mg/kg/day) for a 9-week experiment. During the experimental period, antroquinonol reduced the elevation of systolic and diastolic blood pressure. At the end of the study, we found that the antroquinonol groups had lower serum creatinine, renal endothelin-1, angiotensin II, and malondialdehyde levels and arteriole thickening. We found that the 40 mg/kg/day antroquinonol group had lower renal nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activities, greater nuclear factor erythroid-2, and heme oxygenase-1 expressions. Moreover, we also found that antroquinonol decreased proinflammatory cytokine concentrations in the kidney by modulating the nuclear factor-κB pathway. These results suggest that antroquinonol may ameliorate hypertension and improve renal function by reducing oxidative stress and inflammation in rats with endothelial dysfunction.

Platelets Express Activated P2Y12 Receptor in Patients With Diabetes Mellitus

BACKGROUND

Platelets from patients with diabetes mellitus are hyperactive. Hyperactivated platelets may contribute to cardiovascular complications and inadequate responses to antiplatelet agents in the setting of diabetes mellitus. However, the underlying mechanism of hyperactivated platelets is not completely understood.

METHODS

We measured P2Y₁₂ expression on platelets from patients with type 2 diabetes mellitus and on platelets from rats with diabetes mellitus. We also assayed platelet P2Y₁₂ activation by measuring cAMP and VASP phosphorylation. The antiplatelet and antithrombotic effects of AR-C78511 and cangrelor were compared in rats. Finally, we explored the role of the nuclear factor-κB pathway in regulating P2Y₁₂ receptor expression in megakaryocytes.

RESULTS

Platelet P2Y₁₂ levels are 4-fold higher in patients with type 2 diabetes mellitus compared with healthy subjects. P2Y₁₂ expression correlates with ADP-induced platelet aggregation (r=0.89, P<0.01). P2Y₁₂ in platelets from patients with diabetes mellitus is constitutively activated. Although both AR-C78511, a potent P2Y₁₂ inverse agonist, and cangrelor have similar antiplatelet efficacy on platelets from healthy subjects, AR-C78511 exhibits more powerful antiplatelet effects on diabetic platelets than cangrelor (aggregation ratio 36±3% versus 49±5%, respectively, P<0.05). Using a FeCl₃-injury mesenteric arteriole thrombosis model in rats and an arteriovenous shunt thrombosis model in rats, we found that the inverse agonist AR-C78511 has greater antithrombotic effects on GK rats with diabetes mellitus than cangrelor (thrombus weight 4.9±0.3 mg versus 8.3±0.4 mg, respectively, P<0.01). We also found that a pathway involving high glucose-reactive oxygen species-nuclear factor-κB increases platelet P2Y₁₂ receptor expression in diabetes mellitus.

CONCLUSIONS

Platelet P2Y₁₂ receptor expression is significantly increased and the receptor is constitutively activated in patients with type 2 diabetes mellitus, which contributes to platelet hyperactivity and limits antiplatelet drug efficacy in type 2 diabetes mellitus.

Sodium fluoride induces hypertension and cardiac complications through generation of reactive oxygen species and activation of nuclear factor kappa beta

Human exposure to sodium fluoride through its daily usage is almost inevitable. Cardiovascular and renal dysfunction has been associated with fluoride toxicity. Therefore, this study investigated the mechanism of action of sodium fluoride (NaF) induced hypertension and cardiovascular complications Forty male albino rats of an average of 10 rats per group were used. Group A received clean tap water. Toxicity was induced in Group B to D by administering graded doses of NaF through drinking water ad libitum for 10 days at 150 ppm, 300 ppm, and 600 ppm concentration respectively. Following administration of NaF, there was significant increase in systolic pressure, diastolic pressure and mean arterial pressure. Markers of oxidative stress; malondialdehyde, hydrogen peroxide, advance oxidation protein products, and protein carbonyl were significantly increased in dose-dependent pattern in the cardiac and renal tissues of rats together with significant decrease in the GST activity in NaF-treated rats compared to the control. Also serum markers of inflammation, cardiac, and renal damage including myeloperoxidase, xanthine oxidase, blood urea nitrogen, creatinine, Lactate dehydrogenase (LDH), and Creatinine kinase myocardial band (CK-MB) significantly increased indicating induction of oxidative stress, renal, and cardiac damage after exposure. Histopathology of the kidney and heart revealed aberrations in the histological architecture in NaF-treated rats. Also, immunohistochemistry showed higher expression of nuclear factor kappa beta (NF-kB) in the cardiac and renal tissues of rats administered NaF. Combining all, these results indicate NaF-induced hypertension through generation of reactive oxygen species and activation of renal and cardiac NF-kB expressions. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1089-1101, 2017.