Renal Tumor Necrosis Factor Research Articles

Fucoidan Supplementation Relieved Kidney Injury and Modulated Intestinal Homeostasis in Hyperuricemia Mice.

Hyperuricemia is a metabolic disease characterized by an excessively increased level of uric acid (UA) in the blood, with an increasing prevalence and often associated with kidney damage. Gut microbiota and endotoxins of gut origin are key mediators in the gut-kidney axis that can cause renal impairment. The study was to reveal the protective effects of fucoidan on renal injury caused by hyperuricemia. The hyperuricemia model was established in C57BL/6J mice. After 10 weeks of fucoidan supplementation, we found that the levels of serum UA and creatinine were reduced, and the levels of renal tumor necrosis factor α, interleukin-18 (IL-18), IL-6, and interleukin-1β (IL-1β) were also decreased. Fucoidan inhibited the expressions of phosphorylated NF-κB p65, NLRP3, and activated caspase-1 in the kidneys. Fucoidan also regulated the expressions of Bcl-2 family proteins and decreased the activation of caspase-3, thereby exerting antiapoptotic effect. In addition, fucoidan could reduce the expressions of glucose transporter 9 (GLUT9) and urate transporter 1 (URAT1) proteins, thereby promoting the excretion of UA from the kidneys. Moreover, the protective effect of fucoidan on renal injury may be related to maintaining intestinal homeostasis. Fucoidan reduced serum lipopolysaccharide and improved the intestinal mucosal barrier function. Fucoidan decreased the abundances of Blautia, Muribaculaceae, and Dubosiella, and increased the abundances of Lactobacillus. High-dose fucoidan supplementation increased the content of butyric acid and enhanced the expression of ATP binding box transporter G2 (ABCG2) via the AMPK/AKT/CREB pathway in ileum. Conclusion: Fucoidan could protect against hyperuricemia-induced renal injury by inhibiting renal inflammation and apoptosis and modulating intestinal homeostasis in hyperuricemia mice.

Leukotriene Receptor Antagonist, Montelukast Ameliorates L-NAME-Induced Pre-eclampsia in Rats through Suppressing the IL-6/Jak2/STAT3 Signaling Pathway.

Aims: To investigate the potential protective role of montelukast (Mont) in the pre-eclampsia rat model induced by L-NG-Nitro arginine methyl ester (L-NAME). Methods and materials: Thirty-two pregnant female albino Wistar rats were assigned to four groups: the control group: pregnant rats received vehicles; the Mont group: pregnant rats received Mont (10 mg/kg/day, p.o.) from the 6th to the 18th day of gestation; the L-NAME group: pregnant rats received L-NAME (50 mg/kg/day, i.p.) from the 9th to the 18th day of gestation; the Mont/L-NAME group: pregnant rats received Mont (10 mg/kg/day, p.o.) from the 6th to the 18th day of gestation and L-NAME (50 mg/kg/day, i.p.) from the 9th to the 18th day of gestation. Placental, hepatic, and renal malondialdehyde (MDA), total nitrites (NOx), interleukin 6 (IL-6), and tumor necrosis factor (TNF)-α were determined. Serum alanine transaminase (ALT), aspartate transaminase (AST), creatinine, urea, 24-h urinary protein, and the placental growth factor (PGF) were measured. Histopathological examinations of the placental, hepatic, and renal tissues were also performed. In addition, placental, hepatic, and renal Janus kinase 2 (Jak2) and signal transducer and activator of transcription 3 (STAT3) immunoblotting were performed. Key findings: Mont improves oxidative stress, IL-6, TNF-α, ALT, AST, creatinine, urea, 24-h urinary protein, PGF, Jak2, and STAT3 which were all affected by L-NAME. Moreover, the histopathological assessment indicated that Mont restored the normal architecture that was markedly disturbed by L-NAME. Significance: Mont exerted the biochemical and histopathological amelioration of L-NAME-caused pre-eclampsia through its anti-inflammatory, anti-oxidant function and suppression of the IL-6/Jak2/STAT3 signaling pathway.

Renal TLR7 expression is associated with renal injury in female mouse model of systemic lupus erythematosus

BackgroundSystemic lupus erythematosus (SLE) is an autoimmune disorder associated with exaggerated immune activation, autoantibody production, and immune complex formation. SLE patients are predominantly women of reproductive age that often present with end organ damage, specifically in the kidneys, and hypertension. This detrimental sequelae is likely due to deposition of the immune complexes and the resulting inflammation, but the exact mechanisms are unknown. It is known however that immune complexes activate toll like receptors (TLRs) on immune cells and TLR7 particularly is known to promote the development and acceleration of the pathogenesis of SLE. Therefore, we hypothesized that renal TLR7 drives the renal injury and hypertension in female SLE mice.MethodsDouble‐stranded DNA (dsDNA) autoantibodies, a hallmark of SLE, and albuminuria, a marker of renal injury, were monitored at 30 and 35 weeks of age in female and male SLE (NZBWF1) and control (NZW) mice. Glomerular filtration rate (GFR) was measured by sinistrin clearance and renal TLR7 and tumor necrosis factor (TNF)‐α expression were measured via Western blot to assess renal function and renal inflammation at the end of 35 weeks. Mean arterial pressure was also measured in conscious mice at 35 weeks of age using indwelling arterial catheters.ResultsAt 30 weeks, female SLE mice had elevated plasma dsDNA autoantibodies compared to female controls (4.6e5 ± 1.3e5 vs 8.9e4 ± 3.3e4; n=3‐5; all p<0.05), male SLE mice (6.3e4 ± 2.7e4 U/mL), and male controls (4.8e4 ± 9.3e3). At 30 weeks, 32% (7 out of 22) of female SLE mice had albuminuria versus 5% (1 out of 22) of female controls, 5% (1 out of 20) of male SLE, and no male controls. At 35 weeks, 63% (10 out of 16) of female SLE mice had albuminuria versus 5% (1 out of 22) of female controls, 5% (1 out of 19) of male SLE, and no male controls. GFR was lower in female SLE mice compared to males at this same time point (865 ± 77 vs. 1066 ±60 μL/min/100 g body weight; p=0.029). Female SLE mice expressed a significantly higher renal cortical expression of TLR7 (3.9e5 ± 8.0e4 intensity units) than both female control (7.5e4 ± 2.6e3 intensity units; p < 0.001) and male SLE mice (7.0e4 ± 1.5e4 intensity units; p < 0.001). Renal cortical expression of TNF‐α, a downstream effector of TLR7, was increased in female SLE mice (1.3e6 ± 3.7e5 intensity units) when compared to both female control mice (1.2e5 ± 3.4e4 intensity units; p < 0.001) and male SLE mice (5.1e5 ± 1.6e5 intensity units; p < 0.001). Both female and male SLE mice were hypertensive at 35 weeks: blood pressure was higher in female SLE than female controls (152 ± 5 vs. 126 ± 3 mmHg; n=6‐8; p=0.003) and in male SLE compared to male controls (152 ± 4 vs. 136 ± 4 mmHg; n=6‐11; p=0.041).ConclusionThese data indicate that increased expression of renal TLR7 and TNF‐α is associated with renal injury and hypertension in female SLE mice. In addition, these data suggest a potential sex difference in the pathogenesis of SLE in males. Therapeutic strategies targeting the TLR7 molecular pathway should be further investigated in both female and male lupus nephritis.

Treatment of male and female spontaneously hypertensive rats with TNF-\u03b1 inhibitor etanercept increases markers of renal injury independent of an effect on blood pressure

Hypertension remains the leading risk factor for cardiovascular disease. Young females tend to be protected from hypertension compared with age-matched males. Although it has become increasingly clear that the immune system plays a key role in the development of hypertension in both sexes, few studies have examined how cytokines mediate hypertension in males versus females. We previously published that there are sex differences in the levels of the cytokine tumor necrosis factor (TNF)-α in spontaneously hypertensive rats (SHR). The goal of this study was to test the hypothesis that TNF-α inhibition with etanercept will lower BP in male and female SHR. However, as male SHR have a more pro-inflammatory status than female SHR, we further hypothesize that males will have a greater decrease in BP with TNF-α inhibition than females. Young adult male and female SHR were administered increasing doses of the TNF-α inhibitor etanercept or vehicle twice weekly for 31 days and BP was continuously measured via telemetry. Following treatment, kidneys and urine were collected and analyzed for markers of inflammation and injury. Despite significantly decreasing renal TNF-α levels, renal phospho-NFκB and urinary MCP-1 excretion, etanercept did not alter BP in either male or female SHR. Interestingly, treatment with etanercept increased urinary excretion of protein, creatinine and KIM-1 in both sexes. These results indicate that TNF-α does not contribute to sex differences in BP in SHR but may be vital in the maintenance of renal health.

Protection of Hesperidin against Methotrexate- Induced Nephrotoxicity may be Mediated by Nrf2/HO-1 Pathway

Abstract: Background: Methotrexate (MTX), a successfully used chemotherapeutic in the treatment of various malignancies and autoimmune diseases, might cause severe nephrotoxicity. Here, we aimed at investigating possible nephroprotective effects of hesperidin (HES), a flavanone present in citrus fruits, against MTX-induced toxicity. Methods: Rats were divided into control, HES, MTX, and MTX/HES groups, where HES was administered in a dose of 100 mg/kg/day orally for 8 days and MTX in a single i.p. dose of 20 mg/kg on day 5 of the experiment. Results: Pretreatment with HES significantly improved MTXinduced deteriorated kidney function and structure, as well as reversed MTX effects on renal tumor necrosis factor (TNF)-α level and caspase 3 expression. MTX upregulated renal breast cancer resistance protein (BCRP); an efflux transporter that extrudes MTX from the kidney. Unfortunately, MTX/HES did not show a further increase in BCRP expression but rather showed downregulation. MTX also caused downregulation of renal nuclear factor erythroid 2-related factor 2 (Nrf2) and hemeoxygenase-1 (HO-1) expressions, whereas HES reversed the MTX effect and upregulated renal Nrf2/HO-1. Conclusion: HES conferred protection against MTX-mediated nephrotoxicity, at least in part via anti-inflammatory and anti-apoptotic mechanisms. Nrf2/HO-1 pathway, but not BCRP, may have a role in HES-induced nephroprotection against MTX toxicity. Key words: Methotrexate, Hesperidin, Nrf2, HO-1, TNF-α, Caspase 3, BCRP.

Thalidomide reduces glycerol‐induced acute kidney injury by inhibition of NF-κB, NLRP3 inflammasome, COX-2 and inflammatory cytokines

Acute kidney injury (AKI) is an important clinical complication of rhabdomyolysis. The inflammatory processes are involved in the pathogenesis of AKI induced by rhabdomyolysis. Thalidomide is an anti-inflammatory agent that has been used in the treatment of inflammatory disorders. The aim of this study was to investigate the therapeutic effect of thalidomide and its underlying mechanisms on a mouse model of rhabdomyolysis-induced AKI. Mice were injected with a single dose of glycerol (50%, 10 ml/kg, im) to induce AKI, and treated with thalidomide (40 and 80 mg/kg/day, orally) for 2 days. Renal tissue and blood samples were collected for histological and biochemical analysis. In thalidomide treated mice, blood urea nitrogen (BUN) (59.3 ± 19.6 vs. 223 ± 33 mg/dl), plasma creatinine (0.58 ± 0.3 vs. 1.28 ± 0.3 mg/dl), relative kidney weight (0.93 ± 0.13% vs. 1.22 ± 0.1%) and histopathological damage (1.5 ± 0.8 vs. 3.3 ± 1.1 score) were significantly lower as compared to the glycerol group. The results also showed that the levels of malondialdehyde (MDA) (0.13 ± 0.02 vs. 0.2 ± 0.01 µM/mg), myeloperoxidase (MPO) (0.1 ± 0.05 vs. 0.25 ± 0.02 U/mg) and the expression of nuclear factor kappa B (NF-κB) (1.7-fold), NLRP3 inflammasome (1.4-fold) and cyclooxygenase (COX)-2 (3-fold) in renal tissue were significantly lower in thalidomide treated group than those in the glycerol group. Thalidomide treatment resulted in lower renal pro-inflammatory cytokines tumor necrosis factor (TNF)-α (6.7 ± 0.8 vs. 12.3 ± 1.2 ng/ml), interleukin (IL)-1β (3.2 ± 0.5 vs. 5.1 ± 0.3 pg/mg), IL-6 (24.7 ± 2.4 vs. 33 ± 3 pg/mg) and transforming growth factor (TGF)-β1 (0.6 ± 0.17 vs. 1.56 ± 0.24 ng/ml) than those in the glycerol treated mice. In addition the levels of monocyte chemoattractant protein (MCP)-1 (9.5 ± 1 vs. 12.8 ± 1.1 pg/mg) and intercellular adhesion molecule (ICAM)-1 (22.8 ± 7.8 vs. 53.3 ± 5.5 pg/mg) were significantly lower in renal tissue of mice treated with thalidomide as compared to the glycerol treated mice. In conclusion these data revealed that thalidomide may be a potential therapeutic approach against rhabdomyolysis-induced AKI through inhibition of inflammatory responses.

Moringa oleifera ethanolic extract attenuates tilmicosin-induced renal damage in male rats via suppression of oxidative stress, inflammatory injury, and intermediate filament proteins mRNA expression

Tilmicosin (Til) is a popular macrolide antibiotic, widely used in veterinary practice. The present study was designed to address the efficacy of Moringa oleifera ethanolic extract (MOE) in protecting against Tilmicosin (Til) - induced nephrotoxicity in Sprague Dawley rats. Animals were treated once with Til (75 mg/kg bw, subcutaneously), and/or MOE for 7 days (400 or 800 mg/kg bw, by oral gavage). Til-treatment was associated with significantly increased serum levels of creatinine, urea, sodium, potassium and GGT activity, as well as decreased total protein and albumin concentrations. Renal tissue hydrogen peroxide (H2O2) and malondialdehyde (MDA) levels were elevated, while the activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx) enzymes were diminished. The levels of renal tumor necrosis factor alpha (TNF-α) and interleukin-1 beta (IL-1β) and the mRNA expression of intermediate filament protein encoding genes (desmin, nestin and vimentin) in the kidney were up- regulated with histopathological alterations in renal glomeruli, tubules and interstitial tissue. These toxic effects were markedly ameliorated by co-treatment of MOE with Til, in a dose dependent manner. Taken together, these results indicate that MO at 800 mg/kg protects against Til-induced renal injury, likely by its potent antioxidant and anti-inflammatory properties, which make it suitable to be used as a protective supplement with Til therapy.

Basil (Ocimum basilicum L.) and/or Celery (Apium graveolens L.) Leaves Aqueous Extracts Role in Opposition to Drinking Contaminated Water Induced Male Rats Urinary Stones and Renal Deteriorations

Aims: The current research was designed to explore the role of basil and/or celery leaves aqueous extracts against urinary stones (urolithiasis) and renal deteriorations induced by drinking water contaminated with ethylene glycol (EG) and ammonium chloride (AC) in male rats.
 Place and Duration of Study: The Medical Research Center of the Faculty of Pharmacy, Al-Azhar University, Cairo, Egypt. The experiment duration was 35 days, 7 days for acclimatization followed by 28 days experimentation.
 Methodology: Fifty-five adult male Sprague-Dawley rats were classified randomly into 5 groups of ten animals each, except urolithiatic control group which contained 15 rats. Rats were treated as follow: Group I: healthy control group (HCG), rats drank distilled water and received a placebo 1 ml distilled water daily by intra-gastric tube ; Group II: urolithiatic control group (UCG), rats drank distilled water containing ( 0.75% EG and 1% AC ) and the access to water was ad libitum and received 1 ml distilled water daily by intra-gastric tube.; Group III : urolithiatic rats supplemented with aqueous basil extract(U+ABE), rats drank distilled water containing ( 0.75% EG and 1% AC) and the access to water was ad libitum and supplemented with (200mg/kg body weight) aqueous basil extract daily by intra-gastric tube.; Group IV: urolithiatic rats supplemented with aqueous celery extract(U+ACE), rats drank distilled water containing ( 0.75% EG and 1% AC) and the access to water was ad libitum and supplemented with (200mg/kg body weight) aqueous celery extract daily by intra-gastric tube. ; Group V: urolithiatic rats supplemented with aqueous basil and celery extract(U+ABE+ACE) , rats drank distilled water containing ( 0.75% EG and 1% AC) and the access to water was ad libitum and supplemented with (100mg/kg body weight) aqueous basil extract and (100mg/kg body weight) aqueous celery extract daily by intra-gastric tube. At the end of the study 28 days, 24 h urine samples were collected from each individual animal and then rats were sacrificed under sodium barbiturate anesthesia. Blood samples were collected from the hepatic portal vein, serum was separated for biochemical analyses. Kidney samples were separated for tissue homogenate preparation, urinary bladder and ureters were separated and opened to collect urinary calculi.
 Results: Research results documented that basil and celery aqueous extracts contain significant amount of active constituents including flavonoids and polyphenols. Drinking water contaminated with EG and AC caused significant decrease (p≤0.01) in urine volume, pH, urinary and renal magnesium levels with significant increase (p≤0.01) in urinary and renal calcium, phosphate and oxalate levels. It also caused significant increase in kidney function tests [serum creatinine, uric acid, urea, as well as cystatin C] levels .Also renal enzyme activities of [acidic phosphatase (ACP), alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP)] activities were significantly increased (p≤0.01) with significant decrease in renal lactate dehydrogenase (LDH) activity. Water contamination also induced renal mitochondrial dysfunction (decreased complex-1 activity), apoptosis (increased caspase-3 activity) in association with a state of renal oxidative stress [increased renal malondialdehyde (MDA) level related to decreased renal reduced glutathione (GSH)level and superoxide dismutase (SOD) activity].Inflammation [increased renal tumor necrosis factor- alpha (TNF- α) and interleukin 18 (IL-18)] with suppressed immune function [decreased serum immunoglobulin (IgG and IgM)] levels were observed in urolithiatic control group. As a result of biochemical changes resulted from EG and AM administration mineral precipitation and urinary stones formation was observed in urolithiatic control group. Oral administration of aqueous basil and /or celery extracts to urolithiatic rats improved urine analysis parameters, renal functions, renal enzymes activities and mitochondrial function. Aqueous extracts also counteracted renal oxidative stress, inflammation, suppressed immune response and urinary stones formation.
 Conclusion: Research results proved that aqueous basil and/or celery extracts counteracted and ameliorated urinary stones formation and renal deteriorations associated with drinking water contaminated with EG and AC due to their content of active constituents including flavonoids and polyphenols. The most significant improvements were recorded in the group supplemented with both extracts.

MicroRNA-133a-Dependent Inhibition of Proximal Tubule Angiotensinogen by Renal TNF (Tumor Necrosis Factor).

We showed that intrarenal suppression of TNF (tumor necrosis factor) production under low salt (LS) conditions increases renal cortical AGT (angiotensinogen) mRNA and protein expression. Intrarenal injection of murine recombinant TNF attenuated increases of AGT in mice ingesting LS. Moreover, AGT mRNA and protein expression increased ≈6-fold and 2-fold, respectively, in mice ingesting LS that also received an intrarenal injection of a lentivirus construct that specifically silenced TNF in the kidney (U6-TNF-ex4). Silencing of TNF under normal salt and high salt (HS) conditions also resulted in increased AGT expression. Since renal TNF production decreases in response to LS and increases in response to HS, the data suggest that alterations in TNF production under these conditions modulate the degree of AGT expression. We also tested the hypothesis that TNF inhibits intrarenal AGT expression by a mechanism involving miR-133a. Expression of miR-133a decreased in mice given LS and increased in response to HS for 7 days. Intrarenal silencing of TNF reversed the effects of HS on miR-133a-dependent AGT expression. In contrast, intrarenal TNF administration increased miR-133a expression in the kidney. Collectively, the data suggest that miR-133a is a salt-sensitive microRNA that inhibits AGT in the kidney and is increased by TNF. The HS-induced increase in blood pressure observed following silencing of TNF was markedly reduced upon intrarenal administration of miR-133a suggesting that intrinsic effects of TNF in the kidney to limit the blood pressure response to HS include an increase in miR-133a, which suppresses AGT expression.

RESCUE OF INFLAMMATORY RENAL DAMAGE BY MEDICINAL PLANT EXTRACTS IN DIABETIC RATS

Diabetic nephropathy (DN) is the most critical diabetic complication that leads to renal failure. The purpose of this research was to explore the anti-diabetic effectiveness of Cucumis melo var. flexuosus and/or Phoenix dactylifera fruit aqueous extracts and their mechanisms in alleviating nephropathy in hyperglycemic rats. Diabetes was promoted in rats by injection (i.p.) of a single dose of streptozotocin (STZ). C. flexuosus and P. dactylifera extracts (CFE and PDE respectively) were ingested to diabetic rats for thirty consecutive days. The data revealed that intake of either plant extract or their combination to diabetic rats, significantly diminished the serum glucose and raised the serum insulin concentration. The plant extracts significantly ameliorated the increases in relative kidney weights as well as in renal tumor necrosis factor (TNF-α), serum C –reactive protein (CRP) and renal vascular endothelial factor (VEGF). Serum kidney function markers (creatinine, uric acid and urea) were also decreased in diabetic rats treated with the plant extracts. Histopathological observation was also carried out to confirm the biochemical results. This study has proven that the current plant extracts have potential hypoglycemic effect and could attenuate diabetic inflammatory renal damage in rats. The combination of the two extracts was synergistically the effective one. This result may help in exploring a novel therapy to manage diabetes and its complications.

An experimental study of exenatide effects on renal injury in diabetic rats1.

Purpose To investigate the effects of exenatide on renal injury in streptozotocin-induced diabetic rats. Methods Fifty SD rats were randomly divided into normal control, model, exenatide-1, exenatide-2 and exenatide-3 groups, 10 rats in each group. The diabetic nephropathy model was constructed in later 4 groups. Then, the later 3 groups were treated with 2, 4 and 8 μg/kg exenatide for 8 weeks, respectively. The serum and urine biochemical indexes and oxidative stress and inflammatory indexes in renal tissue were determined. ResultsCompared to the model group, in exenatide-3 group the serum fasting plasma glucose and hemoglobin A1c levels were significantly decreased, the fasting insulin level was significantly increased, the renal index and blood urea nitrogen, serum creatinine and 24 h urine protein levels were significantly decreased, the renal tissue superoxide dismutase and glutathione peroxidase levels were significantly increased, the malondialdehyde level was significantly decreased, and the renal tissue tumor necrosis factor alpha, interleukin 6, hypersensitive C-reactive protein and chemokine (C-C motif) ligand 5 levels were significantly decreased P<0.05). ConclusionsExenatide can mitigate the renal injury in diabetic rats. The mechanisms may be related to its resistance of oxidative stress and inflammatory response in renal tissue.

Role of thymoquinone and ebselen in the prevention of sodium arsenite-induced nephrotoxicity in female rats.

The aim of this study is to investigate the protective effects of thymoquinone (TQ) and ebselen (Eb) on arsenic (As)-induced renal toxicity in female rats. Sodium arsenite was orally administrated at a dose of 20 mg/kg body weight daily for 28 days, either alone or 1 h before TQ (10 mg/kg) or Eb (5 mg/kg) administration. Renal tissue As concentration and oxidative stress markers, including lipid peroxidation (LPO), nitrite/nitrate, and glutathione (GSH) levels, were determined. In addition to the oxidative stress response, antioxidant enzyme activities including that of superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase were measured. Exposure to As elicited a significant increase in As concentration and significant modifications to the redox state of the kidney, as was evidenced by a significant elevation in LPO and nitrite/nitrate concentration, with a concomitant reduction in GSH content and antioxidant enzyme activity. The oxidant/antioxidant imbalance observed in As toxicity was associated with a significant elevation in renal tumor necrosis factor α, interleukin 6, B-cell lymphoma 2 (Bcl-2)-associated X protein, and caspase 3 levels, in addition to a significant decrease in Bcl-2 levels. Post-administration of TQ and Eb markedly prevented As-induced oxidative stress, inflammation, apoptosis, and As accumulation in the renal tissue and reduced histological renal damage. These findings demonstrate that TQ, the main bioactive phytochemical constituent of Nigella sativa seed oil, and Eb, an organoselenium compound, could significantly inhibit As-induced oxidative damage, apoptosis, and inflammation, and significantly attenuate the accumulation of As in renal tissues by facilitating As biomethylation and excretion.

Renal-Specific Silencing of TNF (Tumor Necrosis Factor) Unmasks Salt-Dependent Increases in Blood Pressure via an NKCC2A (Na+-K+-2Cl- Cotransporter Isoform A)-Dependent Mechanism.

We tested the hypothesis that TNF (tumor necrosis factor)-α produced within the kidney and acting on the renal tubular system is part of a regulatory mechanism that attenuates increases in blood pressure in response to high salt intake. Intrarenal administration of a lentivirus construct, which specifically silenced TNF in the kidney, did not affect baseline blood pressure. However, blood pressure increased significantly 1 day after mice with intrarenal silencing of TNF ingested 1% NaCl in the drinking water. The increase in blood pressure, which was continuously observed for 11 days, promptly returned to baseline levels when mice were switched from 1% NaCl to tap water. Silencing of renal TNF also increased NKCC2 (Na+-K+-2Cl- cotransporter) phosphorylation and induced a selective increase in NKCC2A (NKCC2 isoform A) mRNA accumulation in both the cortical and medullary thick ascending limb of Henle loop that was neither associated with a compensatory decrease of NKCC2F in the medulla nor NKCC2B in the cortex. The NaCl-mediated increases in blood pressure were completely absent when NKCC2A, using a lentivirus construct that did not alter expression of NKCC2F or NKCC2B, and TNF were concomitantly silenced in the kidney. Moreover, the decrease in urine volume and NaCl excretion induced by renal TNF silencing was abolished when NKCC2A was concurrently silenced, suggesting that this isoform contributes to the transition from a salt-resistant to salt-sensitive phenotype. Collectively, the data are the first to demonstrate a role for TNF produced by the kidney in the modulation of sodium homeostasis and blood pressure regulation.

Macrophage Depletion Lowered Blood Pressure and Attenuated Hypertensive Renal Injury and Fibrosis.

Monocyte/macrophage recruitment is closely associated with the degree of hypertensive renal injury. We investigated the direct role of macrophages using liposome-encapsulated clodronate (LEC) to deplete monocytes/macrophages in hypertensive renal injury. C57BL/6 mice were treated with a pressor dose of angiotensin (Ang, 1.4 mg/kg/day) II plus LEC or the PBS-liposome for 2 weeks. Ang II mice developed hypertension, albuminuria, glomerulosclerosis, and renal fibrosis. LEC treatment reduced systolic blood pressure (SBP), albuminuria, and protected against renal structural injury in Ang II mice. Ang II significantly increased renal macrophage infiltration (MOMA2+ cells) and the expression of renal tumor necrosis factor α and interleukin β1, which were significantly reduced in Ang II/LEC mice. Ang II increased renal oxidative stress and the expression of profibrotic factors transforming growth factor (TGF) β1 and fibronectin. Ang II also inhibited the phosphorylation of endothelial nitric oxide synthase [phospho-endothelial nitric oxide synthesis (eNOS), ser1177]. LEC treatment reduced renal oxidative stress and TGFβ1 and fibronectin expressions, and increased phospho-eNOS expression in the Ang II mice. In Dahl rats of salt-sensitive hypertension, LEC treatment for 4 weeks significantly attenuated the elevation of SBP induced by high salt intake and protected against renal injury and fibrosis. Our results demonstrate that renal macrophages play a critical role in the development of hypertension and hypertensive renal injury and fibrosis; the underlying mechanisms may be involved in the reduction in macrophage-driven renal inflammation and restoration of the balance between renal oxidative stress and eNOS. Therefore, macrophages should be considered as a potential therapeutic target to reduce the adverse consequences of hypertensive renal diseases.

Abstract 268: Macrophage Depletion Attenuated Renal Injury and Fibrosis in Angiotensin II Hypertensive Mice

Monocyte/macrophage recruitment is closely associated with the degree of hypertensive renal injury. Here we investigated the direct role of macrophage using Liposome encapsulated clodronate (LEC) to deplete monocyte/macrophage in Ang II-induced hypertensive renal injury. C57BL/6 mice were treated with a pressor dose of angiotensin II (Ang, 1.4 mg/kg/day by mini-pump) plus LEC or the PBS-liposome for two weeks. Ang II mice developed hypertension (186 ± 5 vs. 110 ± 4 mmHg in control, p&lt;0.05) , albuminuria (33.9 ± 4.9 vs. 83.6 ± 2.3 μg/mg creatinine in control, p&lt;0.05), glomerulosclerosis and renal fibrosis. LEC reduced Ang II-induced albuminuria (59.6 ± 1.9 μg/mg creatinine, p&lt;0.05) and protected against renal structural injury with a mild reduction in systolic blood pressure (153 ± 3 mmHg, p&lt;0.05). Ang II significantly increased renal macrophage infiltration (MOMA2 + cells) and the protein expression of renal tumor necrosis factor α and interleukin β1, which were significantly reduced in Ang II mice treated with LEC. Ang II increased renal oxidative stress (as demonstrated by increased oxidative fluorescence densities, NADPH oxidative activity and the protein expression of NADPH oxidase subunits gp91phox and p22phox) and the expression of profibrotic factors transform growth factor β1 and fibronectin. Ang II also inhibited the phosphorylation of endothelial nitric oxide synthesis (eNOS, ser1177). LEC revised most of the changes in the Ang II-induced molecules as mentioned above. Our results suggest that renal macrophage is a main mediator to contribute to Ang II-induced hypertensive renal injury and fibrosis, the underlying mechanisms may involve reduction in macrophage-drove renal inflammation and restoration of the balance between renal oxidative stress and eNOS. These findings may lead us to develop a novel therapy directed at targeting the infiltration of macrophages or the macrophages-derived cytokines for treatment of hypertensive renal diseases.

Dietary Fermentable Fibers Attenuate Chronic Kidney Disease in Mice by Protecting the Intestinal Barrier

BackgroundChronic kidney disease (CKD) is a worldwide health problem. Although the pathogenesis of CKD is still unclear, recent studies suggest that systemic inflammation caused by a dysregulated microflora and an impaired intestinal barrier is involved in CKD development. ObjectiveWe investigated the effects of the fermentable dietary fibers (DFs), unmodified guar gum (GG), and partially hydrolyzed GG (PHGG) (i.e., substances with distinct viscosity characteristics) on CKD development, with a particular focus on colonic tight junction (TJ) barriers in mice. MethodsMale 7-wk-old ICR mice were fed an AIN-93G diet that contained 0.25% adenine for 2 wk to induce CKD. Mice fed adenine were then divided into 3 groups and fed the unsupplemented diet (CKD) or a diet containing 10% PHGG (CKD+PHGG) or GG (CKD+GG) for 3 wk. Control (CON) mice were fed an AIN-93G diet without adenine throughout the 5-wk experiment. Plasma urea concentration; the colonic TJ proteins zonula occludens (ZO) 1, ZO2, occludin, junctional adhesion molecule A (JAMA), and claudin isoforms; renal inflammatory cytokines tumor necrosis factor α (Tnfa), interleukin (Il ) 1β (Il1b), and Il6; and cecal short-chain fatty acids (SCFAs) and microflora were analyzed. ResultsCompared with the CON, CKD+PHGG, and CKD+GG groups, the CKD group had a 2.2- to 4.4-fold higher plasma urea concentration and greater expression of inflammatory cytokine genes in the kidney, including Tnfa (4.4- to 48-fold), Il1b (4.6- to 56-fold), and Il6 (8.8- to 115-fold). The CON, CKD+PHGG, and CKD+GG groups had greater expression of colonic TJ proteins including ZO1 (2.9- to 3.7-fold), ZO2 (3.4- to 4.3-fold), occludin (3.0- to 3.3-fold), JAMA (4.4- to 5.4-fold), and claudin 7 (2.1- to 2.6-fold) and higher cecal SCFA (1.8- to 3.5-fold) and Lactobacillus (2.7- to 4.0-fold) concentrations than the CKD group. ConclusionSupplemental feeding with fermentable DFs, such as GG and PHGG, might be effective for the prevention or management of CKD by restoring colonic barrier integrity and microflora composition, as shown in mice.

Effects of l-arginine supplementation associated with continuous or interval aerobic training on chronic heart failure rats

ObjectiveChronic heart failure (CHF) is related with exercise intolerance and impaired nitric oxide (NO) production, which can lead to several functional capacity alterations. Considering the possible superiority of aerobic interval training compared to continuous training and the capacity of l-arginine to restore the NO pathway, the aim of the present study was to investigate whether these treatments are beneficial to exercise capacity, muscle mass preservation and hemodynamic, inflammatory and oxidative stress parameters in CHF rats. MethodsThirty-eight male Wistar rats post 6weeks of myocardial infarction (MI) surgery were randomly assigned into 6 CHF groups: sedentary (SED, n=6); SED+Arg (n=7); ACT (n=8); ACT+Arg (n=5); AIT (n=7); AIT+Arg (n=5). Exercise test capacity (ETC) was performed pre and post 8weeks of intervention. Supplemented rats received Arg (1g/kg) by oral gavage (7×/week). Exercise training was performed on a rat treadmill (5×/week). Hemodynamic variables, tissue collection, congestion, inflammatory cytokines, and oxidative parameters were evaluated at the end of protocols. ResultsAll trained groups showed a superior exercise capacity compared to SED groups on the post-intervention test (p<0.0001). Pulmonary congestion was attenuated in AIT and AIT+Arg compared with the SED group (p<0.05). Left ventricular end-diastolic pressure (LVEDP) was lower in ACT+Arg, AIT, and AIT+Arg groups than SED group (p<0.05). Association of AIT with Arg supplementation was able to improve hemodynamic responses (left ventricular systolic pressure (LVSP), systolic blood pressure (SBP), +dP/dtmax, and −dP/dtmax (p<0.05), likewise, decrease muscular and renal lipid peroxidation and tumor necrosis factor (TNF)-α, and increase interleukin (IL)-10/TNF-α plasmatic levels (p<0.01). Groups that associated aerobic exercise with Arg supplementation (ACT+Arg and AIT+Arg) revealed higher gastrocnemius mass compared to the SED group (p<0.01). ConclusionsBoth aerobic training protocols were capable to improve aerobic capacity, and the association with Arg supplementation was important to attenuate muscle loss. Moreover, interval training associated with Arg supplementation elicits greater improvements in hemodynamic parameters, contributing to reduction in pulmonary congestion, and demonstrated particular responses in the inflammatory profile and in the antioxidant status.

Luteolin Treatment Protects against Renal Ischemia-Reperfusion Injury in Rats.

Renal ischemia-reperfusion (I/R) injury is a common but severe scientific problem. Luteolin has great anti-inflammatory and antioxidant effects. In this study, we studied the effect of luteolin on renal I/R injury in rats. Intragastric administration of luteolin or saline was performed in Sprague-Dawley rats before (40 mg/kg for three days) and after (one day) renal I/R modeling. Kidney and blood samples were harvested to detect the severity of renal injury 24 hours after operation. The results showed that luteolin-treated rats exhibited milder histomorphological changes with lower scores of renal histological lesions; lower blood urea nitrogen and creatinine levels; lower renal malondialdehyde (MDA), 8-oxo-deoxyguanosine (8-OHdG), and myeloperoxidase (MPO) levels; and higher superoxide dismutase (SOD) and catalase (CAT) activities in the kidney. Luteolin attenuated the increased levels of serum and renal tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6, renal high mobility group box-1 (HMGB1), and nuclear factor kappa β (NF-κB) expression levels in I/R rats. Furthermore, luteolin treatment significantly reduced renal cell apoptosis and endoplasmic reticulum (ER) stress caused by renal I/R injury. In conclusion, luteolin improved renal function in I/R rats by reducing oxidative stress, neutrophil infiltration, inflammation, renal cell apoptosis, and expression of HMGB1 and NF-κB, and ER stress.

Investigation of the effect of crocin pretreatment on renal injury induced by infrarenal aortic occlusion

ObjectiveIschemia and reperfusion (IR) injury is an important complication of abdominal aortic surgery, and it mainly affects the lower extremities and remote organs. In the present study, we aimed to investigate the possible protective effect of crocin in IR-mediated kidney damage. Materials and methodsA total of 24 adult male Wistar–Albino rats were equally and randomly separated into three groups as follows: sham laparotomy, IR, and IR + crocin. Infrarenal aortic occlusion and reperfusion was applied for 1 and 2 h, respectively. Tissue samples were removed and collected. Biochemical and histopathologic analyses were performed. ResultsUrea, blood urea nitrogen, creatinine, renal tissue tumor necrosis factor α, interleukin (IL)-6, IL-18, interferon gamma, IL-1β, total oxidant status, and oxidative stress index levels were significantly higher in IR group, when compared with other groups. These improvements were also demonstrated with some parameters including total score of histopathologic damage, Tunel, Bax, and Caspase-3 expression levels, and these parameters were prominently higher in the IR group, when compared with the other groups. Nevertheless, Bcl2 expression degree was prominently lower in the IR group than those in the other two groups. ConclusionsData established from the present study suggest that crocin can preclude renal damage in infrarenal aortic occlusion models.

The liver X receptor agonist TO901317 protects mice against cisplatin-induced kidney injury.

Liver X receptors are in the nuclear receptor superfamily and are contained in the regulation of lipid and cholesterol metabolism. Besides, liver X receptors are considered crucial regulators of the inflammatory response and innate immunity. The current study evaluates the invivo effects that the synthetic liver X receptor agonist TO901317 protects against cisplatin-induced kidney injury in mice. Mice received cisplatin administration through a single intraperitoneal injection (20 mg/kg in saline). And then the mice were treated with the TO901317 by daily gavage (10 mg/kg/day) 12 h postcisplatin administration, and cisplatin nephrotoxicity was evaluated. At 72 h after cisplatin treatment, elevated plasma urea and creatinine levels (P < 0.05) were evidenced which indicates the renal dysfunction of the vehicle-treated mice, consistent with tubular necrosis, protein cast, dilation of renal tubules, and desquamation of epithelial cells in renal tubules. In contrast, the severity of renal dysfunction and histological damage was reduced in TO901317 treated mice (P < 0.05). In accordance, circulating tumor necrosis factor alpha levels, renal tumor necrosis factor alpha, p47(phox), gp91(phox), and protein expression levels and COX-2 mRNA, renal monocyte chemoattractant protein 1, VACAM-1 mRNA and intercellular adhesion molecule-1 contents, and renal prostaglandin E2 amounts, were higher in samples from cisplatin-treated mice in comparison with controls (P < 0.05) but attenuated in the TO901317 treatment group (P < 0.05). Taken together, treatment with the liver X receptor agonist TO901317 ameliorated the inflammatory response and oxidative stress in cisplatin-induced kidney injury in mice.