Sonneratia apetala seed oil attenuates potassium oxonate/hypoxanthine-induced hyperuricemia and renal injury in mice.

Sonneratia apetala seeds are considered as prospective nutraceuticals with a high content of unsaturated fatty acids (UFAs) which are mainly distributed in the oil. It is well-known that UFAs could exhibit urate-lowering potency and protect against renal injury, indicating that S. apetala seed oil (SSO) may possess hypouricemic and nephroprotective effects. Consequently, the present work attempted to probe into the effects and mechanisms of SSO on potassium oxonate/hypoxanthine-induced hyperuricemia and associated renal injury. The results indicated that SSO treatment prominently inhibited the increase of serum uric acid (UA), creatinine (CRE), and urea nitrogen (BUN) levels and hepatic xanthine oxidase (XOD) activity in hyperuricemia mice. Kidney indexes and histopathological lesions were also remarkably ameliorated. Additionally, SSO treatment improved the renal anti-oxidant status in hyperuricemia mice by significantly reversing the increase in ROS and MDA levels as well as the decline in SOD, CAT and GSH-Px activities. SSO dramatically downregulated the expression and secretion of pro-inflammatory factors involving MCP-1, IL-1ß, IL-6, IL-18 and TNF-α elicited by hyperuricemia. Furthermore, after SSO treatment, increased protein expressions of GLUT9, URAT1 and OAT1 in the hyperuricemia mice were obviously reversed. SSO treatment enormously restored Nrf2 activation and subsequent translation of related anti-oxidative enzymes in the kidneys. TXNIP/NLRP3 inflammasome activation was also obviously suppressed by SSO. In conclusion, SSO exerted favorable hypouricemic effects owing to its dual functions of downregulating the XOD activity and modulating the expressions of renal urate transport-associated proteins, and it also could alleviate hyperuricemia-induced renal injury by restoring the Keap1-Nrf2 pathway and blocking the TXNIP/NLRP3 inflammasome activation.

Dietary Modification Alters the Intrarenal Immunologic Micromilieu and Susceptibility to Ischemic Acute Kidney Injury.

The versatility of the intrarenal immunologic micromilieu through dietary modification and the subsequent effects on susceptibility to ischemic acute kidney injury (AKI) are unclear. We investigated the effects of high-salt (HS) or high-fat (HF) diet on intrarenal immunologic micromilieu and development of ischemic AKI using murine ischemic AKI and human kidney-2 (HK-2) cell hypoxia models. Four different diet regimens [control, HF, HS, and high-fat diet with high-salt (HF+HS)] were provided individually to groups of 9-week-old male C57BL/6 mice for 1 or 6 weeks. After a bilateral ischemia-reperfusion injury (BIRI) operation, mice were sacrificed on day 2 and renal injury was assessed with intrarenal leukocyte infiltration. Human kidney-2 cells were treated with NaCl or lipids. The HF diet increased body weight and total cholesterol, whereas the HF+HS did not. Although the HF or HS diet did not change total leukocyte infiltration at 6 weeks, the HF diet and HF+HS diet increased intrarenal CD8 T cells. Plasma cells increased in the HF and HS diet groups. The expression of proinflammatory cytokines including TNF-α, IFN-γ, MCP-1, and RANTES was increased by the HF or HS diet, and intrarenal VEGF decreased in the HS and HF+HS diet groups at 6 weeks. Deterioration of renal function following BIRI tended to be aggravated by the HF or HS diet. High NaCl concentration suppressed proliferation and enhanced expression of TLR-2 in hypoxic HK-2 cells. The HF or HS diet can enhance susceptibility to ischemic AKI by inducing proinflammatory changes to the intrarenal immunologic micromilieu.

Dietary methionine restriction attenuates renal ischaemia/reperfusion-induced myocardial injury by activating the CSE/H2S/ERS pathway in diabetic mice.

Methionine restrictive diet may alleviate ischaemia/reperfusion (I/R)-induced myocardial injury, but its underlying mechanism remains unclear. HE staining was performed to evaluate the myocardial injury caused by I/R and the effect of methionine-restricted diet (MRD) in I/R mice. IHC and Western blot were carried out to analyse the expression of CSE, CHOP and active caspase3 in I/R mice and hypoxia/reoxygenation (H/R) cells. TUNEL assay and flow cytometry were used to assess the apoptotic status of I/R mice and H/R cells. MTT was performed to analyse the proliferation of H/R cells. H2S assay was used to evaluate the concentration of H2S in the myocardial tissues and peripheral blood of I/R mice. I/R-induced mediated myocardial injury and apoptosis were partially reversed by methionine-restricted diet (MRD) via the down-regulation of CSE expression and up-regulation of CHOP and active caspase3 expression. The decreased H2S concentration in myocardial tissues and peripheral blood of I/R mice was increased by MRD. Accordingly, in a cellular model of I/R injury established with H9C2 cells, cell proliferation was inhibited, cell apoptosis was increased, and the expressions of CSE, CHOP and active caspase3 were dysregulated, whereas NaHS treatment alleviated the effect of I/R injury in H9C2 cells in a dose-dependent manner. This study provided a deep insight into the mechanism underlying the role of MRD in I/R-induced myocardial injury.

The dietary isoflavone daidzein mitigates oxidative stress, apoptosis, and inflammation in CDDP-induced kidney injury in rats: Impact of the MAPK signaling pathway.

Cisplatin-induced nephrotoxicity persists as a clinical problem despite several supportive measures to alleviate renal damage. Daidzein (DZ), a dietary isoflavone having antioxidant and anti-inflammatory activity, is investigated in this study for protective effects against cisplatin-induced renal injury in rats. DZ (25, 50, or 100 mg/kg; intraperitoneally; 10 days) was administered along with Cisplatin, single dose, on the 7th day of the experiment. On the 11th day, the rats were euthanized, and different samples were collected for analysis. Biochemical, histopathological, and molecular parameters were assessed to evaluate the effect of daidzein. Cisplatin injection resulted in renal dysfunction, lipid peroxidation that led to consumption of antioxidants, exaggerated apoptosis, and inflammation. These changes were associated with increase in the signaling proteins. DZ attenuated the toxic effects of cisplatin on the kidney at 100 mg/kg dose. The study concludes with the finding that daidzein imparts protection against the nephrotoxic effect of Cisplatin and can be considered as a novel, potential therapy.

Postoperative nutritional support of the patient with gut gangrene-a case report.

BACKGROUND: Bowel necrosis is a commonly observed condition in elderly patients with longstanding diabetes. In such condition, intestinal resection is usually performed for the removal of the gangrenous part. Post-surgical dietary management after bowel resection poses several challenges for the health care team. CASE PRESENTATION: The case presented in this study is that of an elderly diabetic male who developed acute renal failure as a result of neglect in post-surgical feeding after intestinal resection. After the intervention by a trained dietitian, a transitional diet was planned and successfully executed, resulting in reversal of acute renal failure, dehydration, and post-surgical stress. Several complications including hepatic dysfunction and mouth ulcers were resolved through well-planned transitional diet. The patient was finally discharged in a stable health condition and was regularly followed up for any nutritional or medical issues. CONCLUSION: Neglects in nutritional care of patients can have severe implications including development of medical complications, resulting in increased length of hospital stay, augmenting the disease stress of the patient and family, and finally the preventable drainage of several human and monetary resources. Therefore, recognition of nutritional intervention as an important part of in-hospital health care may have social as well as economic impacts.

Fasting reduces oxidative stress, mitochondrial dysfunction and fibrosis induced by renal ischemia-reperfusion injury.

Food deprivation protects against ischemia-reperfusion (IR) injury through unknown mechanisms. In an experimental rat model of acute IR injury, we found that preoperative fasting for 3 days protects rats from tubular damage and renal functional decline by increasing antioxidant protection independently of the NF-E2-related factor 2 (Nrf2), and by maintaining mitochondrial morphology and function. In addition, further analysis revealed that fasting protects against tubulointerstitial fibrosis. In summary, our results point out to fasting as a robust nutritional intervention to limit oxidative stress and mitochondrial dysfunction in early acute kidney injury and also to promote long-term protection against fibrosis.

Effect of methylprednisolone on acute kidney injury in patients undergoing cardiac surgery with a cardiopulmonary bypass pump: a randomized controlled trial.

BACKGROUND: Perioperative corticosteroid use may reduce acute kidney injury. We sought to test whether methylprednisolone reduces the risk of acute kidney injury after cardiac surgery. METHODS: We conducted a prespecified substudy of a randomized controlled trial involving patients undergoing cardiac surgery with cardiopulmonary bypass (2007-2014); patients were recruited from 79 centres in 18 countries. Eligibility criteria included a moderate-to-high risk of perioperative death based on a preoperative score of 6 or greater on the European System for Cardiac Operative Risk Evaluation I. Patients (n = 7286) were randomly assigned (1:1) to receive intravenous methylprednisolone (250 mg at anesthetic induction and 250 mg at initiation of cardiopulmonary bypass) or placebo. Patients, caregivers, data collectors and outcome adjudicators were unaware of the assigned intervention. The primary outcome was postoperative acute kidney injury, defined as an increase in the serum creatinine concentration (from the preoperative value) of 0.3 mg/dL or greater (≥ 26.5 µmol/L) or 50% or greater in the 14-day period after surgery, or use of dialysis within 30 days after surgery. RESULTS: Acute kidney injury occurred in 1479/3647 patients (40.6%) in the methylprednisolone group and in 1426/3639 patients (39.2%) in the placebo group (adjusted relative risk 1.04, 95% confidence interval 0.96 to 1.11). Results were consistent across several definitions of acute kidney injury and in patients with preoperative chronic kidney disease. INTERPRETATION: Intraoperative corticosteroid use did not reduce the risk of acute kidney injury in patients with a moderate-to-high risk of perioperative death who had cardiac surgery with cardiopulmonary bypass. Our results do not support the prophylactic use of steroids during cardiopulmonary bypass surgery. Trial registration: ClinicalTrials.gov, no. NCT00427388.

The effect of white tea on serum TNF-α/NF-κB and immunohistochemical parameters in cisplatin-related renal dysfunction in female rats.

OBJECTIVE: Nephrotoxicity is the most important side effect of the antineoplastic drug cisplatin, thereby restricting its use. The aim of this study was to investigate the protective effects of white tea infusions (WT) against renal damage induced by cisplatin (CP) in rats by biochemical and histopathological means. MATERIALS AND METHODS: This study used 24 female Sprague Dawley rats at 12-14 weeks of age and weighing 250-300 g. Rats were divided into three groups: Control, CP and CP + WT groups. CP was injected 7 mg/kg i.p as a single dose/rat in the CP group. White tea was given at a dose of 0.5% (w/v) for 4 weeks. At the end of the experiment, blood urea nitrogen (BUN), creatinine, uric acid, tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and nuclear factor kappa B (NF-κB) along with caspase-3 in the kidney were evaluated in study. RESULTS: BUN, creatinine, TNF-α, NF-κB and IL-6 levels of the CP group showed a statisically significant increase in comparison to the control group. TNF-α, NF-κB and IL-6 levels showed a statistically significant decrease in the CP + WT group with respect to the CP group. Caspase-3 levels in tubular epithelial cells decreased in CP + WT group compared with CP group (p = 0.02). CONCLUSION: White tea infusions reduced significantly the nephrotoxicity of CP. The anti-nephrotoxic feature of the infusion may be attributed primarily to its anti-inflammatory and anti-apoptotic characteristics.

Dietary methionine restriction modulates renal response and attenuates kidney injury in mice.

Methionine restriction (MR) extends the lifespan across several species, such as rodents, fruit flies, roundworms, and yeast. MR studies have been conducted on various rodent organs, such as liver, adipose tissue, heart, bones, and skeletal muscle, to elucidate its benefits to the healthspan; however, studies of the direct effect of MR on kidneys are lacking. To investigate the renal effects of MR, we used young and aged unilateral nephrectomized and 5/6 nephrectomized (5/6Nx) mice. Our studies indicated that MR mice experienced polydipsia and polyuria compared with control-fed counterparts. Urine albumin, creatinine, albumin-to-creatinine ratio, sulfur amino acids, and electrolytes were reduced in MR mice. Kidneys of MR mice up-regulated genes that are involved in ion transport, such as Aqp2, Scnn1a, and Slc6a19, which indicated a response to maintain osmotic balance. In addition, we identified renoprotective biomarkers that are affected by MR, such as clusterin and cystatin C. Of importance, MR attenuated kidney injury in 5/6Nx mice by down-regulating inflammation and fibrosis mechanisms. Thus, our studies in mice show the important role of kidneys during MR in maintaining osmotic homeostasis. Moreover, our studies also show that the MR diet delays the progression of kidney disease.-Cooke, D., Ouattara, A., Ables, G. P. Dietary methionine restriction modulates renal response and attenuates kidney injury in mice.

Dietary iron restriction alleviates renal tubulointerstitial injury induced by protein overload in mice.

Increased proteinuria causes tubulointerstitial injury due to inflammation in chronic kidney disease (CKD). Iron restriction exhibits protective effects against renal dysfunction; however, its effects against protein overload-induced tubulointerstitial damage remain unclear. Here, we investigated dietary iron restriction effect on tubulointerstitial damage in mice with protein-overload tubulointerstitial injury. Renal tubulointerstitial injury in animal model was induced by intraperitoneal injection of an overdose of bovine serum albumin (BSA). We divided mice into three groups: normal saline + normal diet (ND), BSA + ND, and BSA + iron-restricted diet (IRD). BSA overload induced renal tubulointerstitial injury in the ND mice, which was ameliorated in the IRD mice. Inflammatory cytokines and extracellular matrix mRNA expression was upregulated in BSA + ND mice kidneys and was inhibited by IRD. BSA-induced increase in renal superoxide production, NADPH oxidase activity, and p22phox expression was diminished in the IRD mice. IRD suppression increased BSA-induced renal macrophage infiltration. Moreover, BSA mice exhibited nucleotide-binding oligomerisation domain-like receptor pyrin domain-containing protein (NLRP) inflammasome activation, which was inhibited by IRD. Ferrous iron increased in kidneys with BSA overload and was inhibited by IRD. Thus, iron restriction inhibited oxidative stress and inflammatory changes, contributing to the protective effect against BSA overload-induced tubulointerstitial injury.

Molecular mechanisms of renal aging.

Epidemiologic, clinical, and molecular evidence suggest that aging is a major contributor to the increasing incidence of acute kidney injury and chronic kidney disease. The aging kidney undergoes complex changes that predispose to renal pathology. The underlying molecular mechanisms could be the target of therapeutic strategies in the future. Here, we summarize recent insight into cellular and molecular processes that have been shown to contribute to the renal aging phenotype.The main clinical finding of renal aging is the decrease in glomerular filtration rate, and its structural correlate is the loss of functioning nephrons. Mechanistically, this has been linked to different processes, such as podocyte hypertrophy, glomerulosclerosis, tubular atrophy, and gradual microvascular rarefaction. Renal functional recovery after an episode of acute kidney injury is significantly worse in elderly patients. This decreased regenerative potential, which is a hallmark of the aging process, may be caused by cellular senescence. Accumulation of senescent cells could explain insufficient repair and functional loss, a view that has been strengthened by recent studies showing that removal of senescent cells results in attenuation of renal aging. Other potential mechanisms are alterations in autophagy as an important component of a disturbed renal stress response and functional differences in the inflammatory system. Promising therapeutic measures to counteract these age-related problems include mimetics of caloric restriction, pharmacologic renin-angiotensin-aldosterone system inhibition, and novel strategies of senotherapy with the goal of reducing the number of senescent cells to decrease aging-related disease in the kidney.

Soporte nutricional en lesión renal aguda / Nutritional support in acute kidney injury

El desgaste proteico energético (DPE) es altamente prevalente en pacientes con lesión renal aguda (LRA), lo que incrementa la mortalidad, complicaciones y el uso de recursos sanitarios. Los objetivos del soporte nutricional (SN) incluyen: adecuar el aporte de nutrientes, prevenir el DPE, preservar la masa corporal magra, mantener el estado nutricional, evitar otros trastornos metabólicos, mejorar la cicatrización de heridas, apoyar la función inmune y reducir la mortalidad. Los pacientes con LRA en terapia de reemplazo renal (TRR) deben recibir al menos 1.5 g/kg/d de proteína y no más de 30 kcal no proteicas/kg/d. Se deben tomar en cuenta las pérdidas de macronutrientes y micronutrientes especialmente en los diferentes tipos de TRR, así como las alteraciones metabólicas, subalimentación o sobrealimentación. La nutrición enteral debe ser la primera elección de alimentación, sin embargo, la nutrición parenteral sola o combinada debe ser utilizada para alcanzar los objetivos nutricionales. El SN debe ser temprano durante las primeras 24-48 hrs. Los requerimientos nutricionales y el tipo de SN deben ser individualizados y reevaluados con frecuencia en pacientes con LRA (AU)

Protein-energy wasting (PEW) is highly prevalent in patients with acute kidney injury (AKI), increasing mortality, complications and use of health resources. The goals of nutritional support (NS) include: adequate intake of nutrients, prevent PEW, preservation of lean body mass, maintenance of nutritional status, avoidance of further metabolic derangements, enhancement of wound healing, support of immune function and reduction in mortality. Patients with AKI on renal replacement therapy (RRT) should receive at least 1.5 g/kg/d of protein and not more than 30 nonprotein kcal/kg/d. It should be taken into account losses macronutrients and micronutrients specially in the different types of RRT, metabolic alterations and underfeeding or overfeeding. Enteral nutrition should be the first choice of feeding, however, alone or complementary parenteral nutrition should be used to achieve nutritional goals. NS should be early in the first 24-48 hrs. The nutritional requirements and type of NS should be frequently reassessed and individualized in patients with AKI (AU)

[Nutritional management of kidney diseases in children].

The prevalence of various kidney diseases in children remains high in recent decades. Adequate nutrition management can enhance the effectiveness of drug treatment, slow the frequency of relapses andprevent the progression of the disease. The article is devoted to modern approaches to diet therapy in various kidney diseases in children with the defeat of tubular and glomerular appa ratus. For the first time the therapeutic diets for children with various kidney diseases are presented. Particular attention is paid to diet therapy in nephrotic syndrome (steroid-responsive and steroid-refractory). Dietary approaches with modern formulas for enteral nutrition in cases of steroid therapy complications in children with renal insufficiency (in predialysis stage and on dialysis) are described. Differentiated nutritional approaches for patients with different types of crystalluria are separately presented.

Erythropoietin Administration Promotes Expression of VEGF in Renal Ischemic­Reperfusion Injury in Rat Model.

Background: Acute ischemia-reperfusion (I/R) injury is the most common causes of acute renal failure in daily clinical practice. It has been recognized that endothelial cell dysfunction and microvascular injury as the pathophysiological changes during I/R injury. Protective effects of erythropoietin (EPO) have been demonstrated in various experimental models of I/R induced injury. Therefore, the aim of the present study was to investigate whether EPO administration has renoprotective effect against acute renal failure I/R injury in rats by promotion of endothelial progenitor cells (EPCs) mobilization and neovascularization. Material and Method: Male Sprague-Dawley rats were pretreated with EPO (1,000 IU/kg/day, ip); or the placebo for 3 days before the induction of I/R procedure. On day 4, the bilateral renal occlusion for 30 min operations to produce renal I/R injury or treatment with EPO 30 min before the initiation of I/R were done. At the end of the reperfusion period at day 1 day 2 and day 4, blood and renal tissues were collected to investigate renal function and pathohistological examination. The expression levels of CAV-1 and CD34 were determined for circulating of EPCs in blood, while CD34, CAV-1 and VEGFR-2 were investigated for mobilized EPCs in kidney, using real time PCR. The expression level of VEGF was also examined to indicate the angiogenesis in kidney using real time PCR and western blotting. Results: In the I/R group, the significantly increased values of serum urea and creatinine were found on Day 1 after ischemia, as compared to sham group. The development of tubular epithelial cell necrosis, peritubular capillary congestion and mild interstitial infiltration has been observed in this group. Administration of EPO in I/R rat was significantly improved renal function and significantly less the tubular damage. The treatment with EPO significantly increased in expression levels of CD34 and CAV-1 in blood, and also CAV-1, VEGFR-2 and VEGF in kidney tissue in this group, as compared to the I/R group. Conclusion: These results suggest that treatment with EPO protects the kidney from ischemic acute renal injury via increasing the mobilization and recruitment of EPCs, resulting in the induction of expression of VEGF that might play an important role in the repair response.

Special nutrition challenges: current approach to acute kidney injury.

Acute kidney injury (AKI), previously known as acute renal failure, is defined as a sudden decline in glomerular filtration rate with accumulation of metabolic waste products, toxins, and drugs, as well as alteration in the intrinsic functions of the kidney. Reports of mortality are as high as 80%, with numerous contributing causes including infection, cardiorespiratory complications, and cardiovascular disease. Concurrent with the high prevalence of critical illness in this population is the protein energy wasting (PEW), seen in up to 42% of patients upon intensive care unit admission. The pathophysiologic derangements of critical illness, the low energy and protein stores, and uremic complications require early nutrition intervention to attenuate the inflammatory response and oxidative stress, improve endothelial function, stabilize blood sugar, and preserve lean body mass. This article addresses the unique challenges of nutrition support for the patient with AKI in the setting of critical illness and renal replacement therapy. Evidence-based recommendations are provided to meet the macronutrient and micronutrient requirements of this heterogeneous and complex patient population.

Nutritional evaluation and management of AKI patients.

Protein-energy wasting is common in patients with acute kidney injury (AKI) and represents a major negative prognostic factor. Nutritional support as parenteral and/or enteral nutrition is frequently needed because the early phases of this are often a highly catabolic state, although the optimal nutritional requirements and nutrient intake composition remain a partially unresolved issue. Nutrient needs of patients with AKI are highly heterogeneous, depending on different pathogenetic mechanisms, catabolic rate, acute and chronic comorbidities, and renal replacement therapy (RRT) modalities. Thus, quantitative and qualitative aspects of nutrient intake should be frequently evaluated in this clinical setting to achieve better individualization of nutritional support, to integrate nutritional support with RRT, and to avoid under- and overfeeding. Moreover, AKI is now considered a kidney-centered inflammatory syndrome; indeed, recent experimental data indicate that specific nutrients with anti-inflammatory effects could play an important role in the prevention of renal function loss after an episode of AKI.

Impact of early parenteral nutrition on metabolism and kidney injury.

A poor nutritional state and a caloric deficit associate with increased morbidity and mortality, but a recent multicenter, randomized controlled trial found that early parenteral nutrition to supplement insufficient enteral nutrition increases morbidity in the intensive care unit, including prolonging the duration of renal replacement therapy, compared with withholding parenteral nutrition for 1 week. Whether early versus late parenteral nutrition impacts the incidence and recovery of AKI is unknown. Here, we report a prespecified analysis from this trial, the Early Parenteral Nutrition Completing Enteral Nutrition in Adult Critically Ill Patients (EPaNIC) study. The timing of parenteral nutrition did not affect the incidence of AKI, but early initiation seemed to slow renal recovery in patients with stage 2 AKI. Early parenteral nutrition did not affect the time course of creatinine and creatinine clearance but did increase plasma urea, urea/creatinine ratio, and nitrogen excretion beginning on the first day of amino acid infusion. In the group that received late parenteral nutrition, infusing amino acids after the first week also increased ureagenesis. During the first 2 weeks, ureagenesis resulted in net waste of 63% of the extra nitrogen intake from early parenteral nutrition. In conclusion, early parenteral nutrition does not seem to impact AKI incidence, although it may delay recovery in patients with stage 2 AKI. Substantial catabolism of the extra amino acids, which leads to higher levels of plasma urea, might explain the prolonged duration of renal replacement therapy observed with early parenteral nutrition.