The changing epidemiology of acute renal failure

Prevention and Therapy of Acute Kidney Injury in the Developing World

Timely recognition of patients at risk or with possible acute kidney injury (AKI) is essential for early intervention to minimize further damage and improve outcome. Initial management of patients with suspected and persistent AKI should include thorough clinical assessment of all patients with AKI to identify reversible factors, including fluid volume status, potential nephrotoxins, and an assessment of the underlying health of the kidney. Based on these assessments, early interventions to provide appropriate and adequate fluid resuscitation while avoiding fluid overload, removal of nephrotoxins, and adjustment of drug doses according to the level of kidney function derangement are important. The judicious use of diuretics for fluid overload and/or in cardiac decompensated patients and introduction of early enteral nutritional support need to be considered to improve outcomes in AKI. Although these basic principles are well recognized, their application in clinical practice in low resource settings is often limited due to lack of education, availability of resources, and lack of trained personnel, which limits access to care. We report the consensus recommendations of the 18th Acute Dialysis Quality Initiative meeting in Hyderabad, India, on strategies to evaluate patients with suspected AKI and initiate measures for prevention and management to improve outcomes, particularly in low resource settings. These recomendations provide a framework for caregivers, who are often primary care physicians, nurses, and other allied healthcare personnel, to manage patients with AKI in resource poor countries.

Tubular Peroxiredoxin 3 as a Predictor of Renal Recovery from Acute Tubular Necrosis in Patients with Chronic Kidney Disease

Peroxiredoxin 3 (PRX3) is a mitochondrial antioxidant that regulates apoptosis in various cancers. However, whether tubular PRX3 predicts recovery of renal function following acute kidney injury (AKI) remains unknown. This retrospective cohort study included 54 hospitalized patients who had AKI with biopsy-proven acute tubular necrosis (ATN). The study endpoint was renal function recovery within 6 months. Of the 54 enrolled patients, 25 (46.3%) had pre-existing chronic kidney disease (CKD) and 33 (61%) recovered renal function. Tubular PRX3 expression was higher in patients with ATN than in those without renal function recovery. The level of tubular but not glomerular PRX3 expression predicted renal function recovery from AKI (AUROC = 0.76). In multivariate Cox regression analysis, high PRX3 expression was independently associated with a higher probability of renal function recovery (adjusted hazard ratio = 8.99; 95% CI 1.13-71.52, P = 0.04). Furthermore, the discriminative ability of the clinical model for AKI recovery was improved by adding tubular PRX3. High tubular PRX3 expression was associated with a higher probability of renal function recovery from ATN. Therefore, tubular PRX3 in combination with conventional predictors can further improve recovery prediction and may help with risk stratification in AKI patients with pre-existing CKD.

Incidence, aetiology and outcome of community-acquired acute kidney injury in medical admissions in Malawi

BACKGROUND

Epidemiological data on Acute Kidney Injury (AKI) from low-income countries is sparse. The aim of this study was to establish the incidence, severity, aetiology, and outcomes of community-acquired AKI in Malawi.

METHODS

We conducted a prospective observational study of general medical admissions to a tertiary hospital in Blantyre between 27^th April and 17^th July 2015. All patients were screened on admission with a serum creatinine; those with creatinine above laboratory reference range were managed by the nephrology team. Hospital outcome was recorded in all patients.

RESULTS

Eight hundred ninety-two patients were included; 188 (21 · 1%) had kidney disease on admission, including 153 (17 · 2%) with AKI (median age 41 years; 58 · 8% HIV seropositive). 60 · 8% of AKI was stage 3. The primary causes of AKI were sepsis and hypovolaemia in 133 (86 · 9%) cases, most commonly gastroenteritis (n = 29; 19 · 0%) and tuberculosis (n = 18; 11 · 8%). AKI was multifactorial in 117 (76 · 5%) patients; nephrotoxins were implicated in 110 (71 · 9%). Inpatient mortality was 44 · 4% in patients with AKI and 13 · 9% if no kidney disease (p <0.0001). 63 · 2% of patients who recovered kidney function left hospital with persistent kidney injury.

CONCLUSION

AKI incidence is 17 · 2% in medical admissions in Malawi, the majority is severe, and AKI leads to significantly increased in-hospital mortality. The predominant causes are infection and toxin related, both potentially avoidable and treatable relatively simply. Effective interventions are urgently required to reduce preventable young deaths from AKI in this part of the world.

Validity of Klotho, CYR61 and YKL-40 as ideal predictive biomarkers for acute kidney injury: review study

CONTEXT AND OBJECTIVE:

Acute kidney injury (AKI) is still a headache for clinicians and scientists as a possible reason for increased death among intensive care unit (ICU) patients after invasive cardiac surgery. Furthermore, the diagnostic process for AKI using conventional biomarkers is not sufficient to ensure early warning of this condition because of the morbid influence of non-renal factors that definitively delay the time for the prognosis. These imposed limitations have led to significant amounts of research targeted towards identifying novel biomarkers for AKI with a sustained degree of sensitivity and specificity. Here, we reviewed previous studies conducted on the Klotho, CYR61 and YKL-40 biomarkers in relation to AKI.

DESIGN AND SETTING:

Review of the literature conducted in the Institute of Clinical Chemistry & Biochemistry, Ljubljana University Medical Center, Slovenia.

METHODS:

The literature was searched in PubMed and the Cochrane Library. From the database of this specialty, we selected 17 references that matched our context for detailed analysis and further investigation.

RESULTS:

The studies reviewed showed notable differences in their results relating to the diagnostic impact of Klotho, CYR61 and YKL-40 on early prediction of AKI.

CONCLUSIONS:

The results regarding the Klotho, CYR61 and YKL-40 biomarkers showed markedly equivocal performance in the previous studies and did not fulfill the expectations that these factors would form valid possible biomarkers for AKI.

Etiology, clinical profile and short-term outcome of acute kidney injury in children at a tertiary care pediatric nephrology center in Pakistan

Background: The reported prevalence rates and etiologies of acute kidney injury (AKI) are quite variable in different regions of the world. The current study was planned to determine the etiology, clinical profile, and short-term outcome of pediatric AKI at our hospital.

Methods: A prospective, observational study was carried out from April 2014 to March 2015. All pediatric patients (1 month to ≤15 years) diagnosed as AKI using modified pRIFLE criteria were studied and followed for 3 months to document short-term outcome.

Results: AKI was diagnosed in 116 children. The mean age was 7.5 ± 4.4 years and males were predominant (60.3%). At presentation, 83.6% had oliguria/anuria, 37.1% hypertension and 17.2% severe anemia. Etiology included primary renal (74/116; 63.8%), postrenal (28/116; 24.1%) and prerenal (11/116; 9.5%) causes. Postinfectious glomerulonephritis (PIGN) and crescentic glomerulonephritis in primary renal, obstructive urolithiasis in postrenal and sepsis in prerenal, were the most common etiologies. At presentation, 89/116 (76.7%) patients were in pRIFLE Failure category. Regarding outcome, 68 (58.6%) patients recovered, six (5.2%) died, 18 (15.5%) developed chronic kidney disease (CKD) and 22 (19%) end-stage renal disease (ESRD). Comparison of recovered and unrecovered AKI showed that characteristics such as hypertension, severe anemia, edema, volume overload, requirement of mechanical ventilation, initiation of dialysis and need of >5 sessions of dialysis had statistically significant (p <0.05) association with nonrecovery.

Conclusion: Glomerulonephritides (PIGN and crescentic) and obstructive urolithiasis are major causes of pediatric AKI at our center. A fairly high percentage of cases recovered and these mainly comprised of PIGN and obstructive urolithiasis.

Molecular mechanisms and cell signaling of 20-hydroxyeicosatetraenoic acid in vascular pathophysiology

Cytochrome P450s enzymes catalyze the metabolism of arachidonic acid to epoxyeicosatrienoic acids (EETs), dihydroxyeicosatetraenoic acid and hydroxyeicosatetraeonic acid (HETEs). 20-HETE is a vasoconstrictor that depolarizes vascular smooth muscle cells by blocking K+ channels. EETs serve as endothelial derived hyperpolarizing factors. Inhibition of the formation of 20-HETE impairs the myogenic response and autoregulation of renal and cerebral blood flow. Changes in the formation of EETs and 20-HETE have been reported in hypertension and drugs that target these pathways alter blood pressure in animal models. Sequence variants in CYP4A11 and CYP4F2 that produce 20-HETE, UDP-glucuronosyl transferase involved in the biotransformation of 20-HETE and soluble epoxide hydrolase that inactivates EETs are associated with hypertension in human studies. 20-HETE contributes to the regulation of vascular hypertrophy, restenosis, angiogenesis and inflammation. It also promotes endothelial dysfunction and contributes to cerebral vasospasm and ischemia-reperfusion injury in the brain, kidney and heart. This review will focus on the role of 20-HETE in vascular dysfunction, inflammation, ischemic and hemorrhagic stroke and cardiac and renal ischemia reperfusion injury.

Prognostic Usefulness of Acute Kidney Injury After Transcatheter Aortic Valve Replacement

Acute kidney injury (AKI) after transcatheter aortic valve replacement (TAVR) has been associated with increased postoperative morbidity and mortality. Long-term outcomes after TAVR with the Edwards SAPIEN valve in patients who develop AKI postoperatively are currently not well described. We retrospectively reviewed 384 consecutive patients undergoing TAVR at 2 institutions from August 2006 to April 2012. AKI was defined and staged according to Valve Academic Research Consortium-2 criteria. The incidence, multivariate predictors, and association of AKI with 3-year mortality were evaluated. Stage 1 AKI occurred in 24.0% of patients (92 of 384), stage 2 in 5.5% (21 of 384), and stage 3 in 8.1% (31 of 384). The overall operative mortality rate was 7.6%, with a mortality of 3.0% in patients with no kidney injury, 7.6% in stage 1, 23.8% in stage 2, and 32.3% in stage 3. The incidence of new postoperative dialysis was 3.1%. Survival at 3 years for no-AKI/stage 1/stage 2/stage 3 was 59.2 ± 3.3%, 43.4 ± 5.2%, 27.8 ± 10.0%, and 25.4 ± 7.9%, respectively. Logistic regression modeling for the combination of stage 2 or 3 AKI after surgery demonstrated that the last preoperative creatinine (for each 1 mg/dl increase, odds ratio = 3.23, 95% CI 1.83 to 5.69; p <0.001) and dye load (for each 10 ml increase, odds ratio = 1.04, 95% CI 1.01 to 1.08; p = 0.006) were significant predictors for AKI. In conclusion, AKI after TAVR is associated with increased postoperative and 3-year mortality. Significant multivariate predictors are potentially modifiable before the procedure.

Major comorbid disease processes associated with increased incidence of acute kidney injury

Acute kidney injury (AKI) is commonly seen amongst critically ill and hospitalized patients. Individuals with certain co-morbid diseases have an increased risk of developing AKI. Thus, recognizing the co-morbidities that predispose patients to AKI is important in AKI prevention and treatment. Some of the most common co-morbid disease processes that increase the risk of AKI are diabetes, cancer, cardiac surgery and human immunodeficiency virus (HIV) acquired immune deficiency syndrome (AIDS). This review article identifies the increased risk of acquiring AKI with given co-morbid diseases. Furthermore, the pathophysiological mechanisms underlying AKI in relation to co-morbid diseases are discussed to understand how the risk of acquiring AKI is increased. This paper reviews the effects of various co-morbid diseases including: Diabetes, cancer, cardiovascular disease and HIV AIDS, which all exhibit a significant increased risk of developing AKI. Amongst these co-morbid diseases, inflammation, the use of nephrotoxic agents, and hypoperfusion to the kidneys have been shown to be major pathological processes that predisposes individuals to AKI. The pathogenesis of kidney injury is complex, however, effective treatment of the co-morbid disease processes may reduce its risk. Therefore, improved management of co-morbid diseases may prevent some of the underlying pathology that contributes to the increased risk of developing AKI.

Aetiologies and Short-term Outcomes of Acute Kidney Injury in a Tertiary Centre in Southwest Nigeria

BACKGROUND

Acute kidney injury (AKI) has become a global health problem and is associated with increased morbidity, mortality and overall health expenditure. Information on the epidemiology and outcomes of AKI will help to audit practice and advocate for policies that will reduce this burden. This study determined aetiologies, short term outcomes and their predictors in AKI patients in a tertiary hospital in Southwest Nigeria.

METHODS

This was an 18-month retrospective study that involved 91 patients with AKI. The socio-demographic information, aetiology, severity and the treatment given to patients were recorded. Outcomes and their predictors were determined using multivariate analysis. P value < 0.05 was taken as statistically significant.

RESULTS

The mean age of the study population was 45.12 ±20.67 years. Common causes of AKI were sepsis in 50(54.9%), hypovolaemia in 23(25.3%), cardiac failure in 7(7.7%) and eclampsia in 6(6.6%). Fifty-seven (62.6%) presented with stage 3. Thirty-one (34.1%) had haemodialysis. Forty-eight (52.7%) had complete renal recovery, 35(38.5%) died and 3(3.3%) left against medical advice while five (5.5%) were referred to other hospitals. Stage 3 AKI (Adjusted odd ratio: 6.79, confidence interval: 1.21:38.04, p = 0.029) and age ≥ 65 years (Adjusted odd ratio: 4.14, confidence interval: 1.32-13.04, p = 0.015) were significant predictors of mortality in AKI patients.

CONCLUSION

Sepsis and hypovolaemia were the commonest causes of AKI. The associated mortality is still high and factors associated with mortality were late presentation and older age. Early presentation, treatment and making haemodialysis affordable are key to improving AKI outcomes.

Effect of Sardina pilchardus oil on alloxan-induced diabetic rats

The purpose of this study was to prevent or to delay the onset of diabetes-related complications, by using a natural marine resource, Sardina pilchardus oil, administrated to alloxan-induced diabetic rats showing hyperglycemia and hyperlipidemia. Gas chromatography-mass spectrometry analysis of the sardine oil detected 18 constituents. The major ones were n-3 highly unsaturated fatty acids among which are docosahexaenoic acid (25.09%) and eicosapentaenoic acid (19.61%). Sardine oil inhibited the α-amylase activity in rats' sera (26.82%) and thus improved glycemia (54%). The supplement of this oil protected the β-cells from death and damage, significantly decreased total triglycerides, total cholesterol and LDL-cholesterol concentrations in diabetic rats' sera and increased the HDL-cholesterol level. Gavage administration of this oil to rats protected the liver and kidney functions by reducing the aspartate transaminase, alanine transaminase and phosphatase alkaline activities, and by decreasing creatinine, urea and uric acid levels.

Intermedin protects against renal ischemia-reperfusion injury by inhibiting endoplasmic reticulum stress

Background

Intermedin (IMD) is a novel member of the calcitonin/calcitonin gene-related peptide family. Endoplasmic reticulum stress (ERS) has been implicated in the pathology of renal ischemia/reperfusion (IRI). In the present study, we investigated whether IMD could reduce ERS damage after renal ischemia.

Methods

The kidneys of SD rats were subjected to 45 min of warm ischemia followed by 24 h of reperfusion. The hypoxia/reoxygenation(H/R) model in NRK-52E cells consisted of hypoxia for 1 h and reoxygenation for 2 h. IMD was over-expressed in vivo and in vitro using the vector pcDNA3.1-IMD. The serum creatinine concentration and lactate dehydrogenase (LDH) activity in the plasma were determined. Histologic examinations of renal tissues were performed with PAS staining. Real-time PCR and Western blotting were used to determine the mRNA and protein levels, respectively. Additionally, ER staining was used to detect the ERS response.

Results

In the rat renal IRI model, we found that IMD gene transfer markedly improved renal function and pathology and decreased LDH activity and cell apoptosis compared with the kidneys that were transfected with the control plasmid. IMD significantly attenuated the ERS stress parameters compared with IRI group. Indeed, IMD down-regulated glucose-regulated protein 78 (GRP78), C/EBP homologous protein(CHOP), and caspase 12 protein and mRNA levels. Moreover, in the NRK-52E cell H/R model, IMD overexpression prevented the apoptosis induced by H/R. Furthermore, IMD ameliorated the ER structural changes and concomitantly decreased the levels of GRP78, CHOP and caspase-12.

Conclusion

This study revealed that IMD protects against renal IRI by suppressing ERS and ERS-related apoptosis.

Sildenafil obviates ischemia-reperfusion injury-induced acute kidney injury through peroxisome proliferator-activated receptor γ agonism in rats

BACKGROUND

Sildenafil is a phosphodiesterase inhibitor used clinically for treating erectile dysfunction. Few studies suggest sildenafil to be a renoprotective agent. The present study investigated the involvement of peroxisome proliferator-activated receptor γ (PPAR-γ) in sildenafil-mediated protection against ischemia-reperfusion-induced acute kidney injury (AKI) in rats.

MATERIALS AND METHODS

The rats were subjected to ischemia-reperfusion injury (IRI) with 40 min of bilateral renal ischemia followed by reperfusion for 24 h. The renal damage was assessed by measuring creatinine clearance, blood urea nitrogen, plasma uric acid, electrolytes, and microproteinuria in rats. The thiobarbituric acid reactive substances, superoxide anion generation, and reduced glutathione levels were measured to assess oxidative stress in renal tissues. The hematoxylin-eosin staining was carried out to demonstrate histopathologic changes in renal tissues. Sildenafil (0.5 and 1.0 mg/kg, intraperitoneal) was administered 1 h before subjecting the rats to renal IRI. In a separate group, bisphenol A diglycidyl ether (30 mg/kg, intraperitoneal), a PPAR-γ receptor antagonist, was given before sildenafil administration followed by IRI.

RESULTS

The ischemia-reperfusion demonstrated marked AKI with significant changes in serum and urinary parameters, enhanced oxidative stress, and histopathologic changes in renal tissues. The administration of sildenafil demonstrated significant protection against ischemia-reperfusion-induced AKI. The prior treatment with bisphenol A diglycidyl ether abolished sildenafil-mediated renal protection, thereby confirming involvement of PPAR-γ agonism in the sildenafil-mediated renoprotective effect.

CONCLUSIONS

It is concluded that sildenafil protects against ischemia-reperfusion-induced AKI through PPAR-γ agonism in rats.

Alleviation of apoptosis of bone marrow-derived mesenchymal stem cells in the acute injured kidney by heme oxygenase-1 gene modification

Bone marrow-derived mesenchymal stem cells (BMSCs) transplantation is beneficial for the treatment of acute kidney injury (AKI), but the poor survival of BMSCs limits the repair effect. The oxidative stress in the AKI microenvironment is regarded as the main reason. Considering the potent anti-oxidant ability of heme oxygenase-1 (HO-1), HO-1 overexpression in BMSCs can be expected to improve the survival of BMSCs and correspondingly enhance the AKI repair effect. Here, BMSCs are transfected with pLV-HO-1/eGFP and pLV-eGFP by the lentivirus vector to get HO-1-BMSCs and eGFP-BMSCs, respectively. Ischemia/reperfusion-AKI kidney homogenate supernatant (KHS) is prepared for treating BMSCs, eGFP-BMSCs and HO-1-BMSCs. AKI-KHS results in a high inhibitory rate of BMSCs growth and a high proportion of TUNEL positive BMSCs, while HO-1 overexpression inverses this phenomenon and re-establishes the antioxidant and oxidant balance in HO-1-BMSCs. Phosphorylations of p53 and p38 mitogen-activated protein kinases (p38 MAPK) in HO-1-BMSCs decrease. Lower levels of monocyte chemotactic protein 1, tumor necrosis factor-α and interleukin 1β are also observed in supernatant of HO-1-BMSCs. The in vivo study shows that HO-1 overexpression sharply decreases the apoptosis of BMSCs in the injured kidney, and correspondingly the renal function of the AKI rats improves significantly. In conclusion, BMSCs with HO-1 overexpression suggests a better survival in the I/R-AKI microenvironment and a better kidney repair effect. The anti-oxidant effect via the inactivations of the downstream p53 and p38MAPK in BMSCs and the anti-inflammation could be the mechanisms. It provides a novel approach for the cell-based AKI-therapy.

Zebrafish Models of Kidney Damage and Repair

The vertebrate kidney possesses the capacity to repair damaged nephrons, and this potential is conserved regardless of the complexity of species-specific kidneys. However, many aquatic vertebrates possess the ability to not only repair existing nephrons, but also generate new nephrons after injury. Adult zebrafish have the ability to recover from acute renal injury not only by replacing lost injured epithelial cells of endogenous nephrons, but by also generating de novo nephrons. This strong regeneration potential, along with other unique characteristics such as the high degree of genetic conservation with humans, the ease of harvesting externally fertilized, transparent embryos, the accessibility to larval and adult kidneys, and the ability to perform whole organism phenotypic small molecule screens, has positioned zebrafish as a unique vertebrate model to study kidney injury. In this review, we provide an overview of the contribution of zebrafish larvae/adult studies to the understanding of renal regeneration, diseases, and therapeutic discovery.

Transcatheter aortic valve implantation in patients with pre-existing chronic kidney disease

BACKGROUND

We investigated the effect of chronic kidney disease (CKD) on morbidity and mortality following transcatheter aortic valve implantation (TAVI) including patients on haemodialysis, often excluded from randomised trials.

METHODS AND RESULTS

We performed a retrospective post hoc analysis of all patients undergoing TAVI at our centre between 2008 and 2012. 118 consecutive patients underwent TAVI; 63 were considered as having (CKD) and 55 not having (No-CKD) significant pre-existing CKD, (defined as estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m²). Chronic haemodialysis patients (n = 4) were excluded from acute kidney injury (AKI) analysis. Following TAVI, in CKD and No-CKD patients respectively, AKI occurred in 23.7% and 14.5% (p = 0.455) and renal replacement therapy (RRT) was necessary in 8.5% and 3.6% (relative risk (RR) [95% CI] = 2.33 [0.47-11.5], p = 0.440); 30-day mortality rates were 6.3% and 1.8% (p = 0.370); and 1-year mortality rates were 17.5% and 18.2% (p = 0.919). Patients who developed AKI had a significantly increased risk of 30-day (12.5% vs. 1.1%, p = 0.029) mortality. We found the presence of diabetes (odds ratio (OR) [95% CI] = 4.58 [1.58-13.3], p = 0.005) and elevated baseline serum creatinine (OR [95% CI] = 1.02 [1.00-1.03], p = 0.026) to independently predict AKI to statistical significance by multivariate analysis.

CONCLUSION

TAVI is a safe, acceptable treatment for patients with pre-existing CKD, however caution must be exercised, particularly in patients with pre-existing diabetes mellitus and elevated pre-operative serum creatinine levels as this confers a greater risk of AKI development, which is associated with increased short-term post-operative mortality.

KIM-1-mediated phagocytosis reduces acute injury to the kidney

Kidney injury molecule 1 (KIM-1, also known as TIM-1) is markedly upregulated in the proximal tubule after injury and is maladaptive when chronically expressed. Here, we determined that early in the injury process, however, KIM-1 expression is antiinflammatory due to its mediation of phagocytic processes in tubule cells. Using various models of acute kidney injury (AKI) and mice expressing mutant forms of KIM-1, we demonstrated a mucin domain-dependent protective effect of epithelial KIM-1 expression that involves downregulation of innate immunity. Deletion of the mucin domain markedly impaired KIM-1-mediated phagocytic function, resulting in increased proinflammatory cytokine production, decreased antiinflammatory growth factor secretion by proximal epithelial cells, and a subsequent increase in tissue macrophages. Mice expressing KIM-1Δmucin had greater functional impairment, inflammatory responses, and mortality in response to ischemia- and cisplatin-induced AKI. Compared with primary renal proximal tubule cells isolated from KIM-1Δmucin mice, those from WT mice had reduced proinflammatory cytokine secretion and impaired macrophage activation. The antiinflammatory effect of KIM-1 expression was due to the interaction of KIM-1 with p85 and subsequent PI3K-dependent downmodulation of NF-κB. Hence, KIM-1-mediated epithelial cell phagocytosis of apoptotic cells protects the kidney after acute injury by downregulating innate immunity and inflammation.

Acute Kidney Injury in the Critically Ill Patient: A Current Review of the Literature

PURPOSE

A comprehensive review of the literature to provide a focused and thorough update on the issue of acute kidney injury (AKI) in the surgical patient.

METHODS

A PubMed and Medline search was performed and keywords included AKI, renal failure, critically ill, and renal replacement therapy (RRT).

PRINCIPAL FINDINGS

A common clinical problem encountered in critically ill patients is AKI. The recent consensus definitions for the diagnosis and classification of AKI (ie, Risk, Injury, Failure, Loss of kidney function, and End-stage kidney disease/Acute Kidney Injury Network) have enabled us to standardize the severity of AKI and facilitate strategies for prevention. These strategies as well as treatment modalities of AKI are discussed. We provide a concise overview of the issue of renal failure. We describe strategies for prevention including types of fluids used for resuscitation, timing of initiation of RRT, and different treatment modalities currently available for clinical practice.

CONCLUSIONS

Acute kidney injury is a common problem in the critically ill patient and is associated with worse clinical outcomes. A standardized definition and staging system has led to improved diagnosis and understanding of the pathophysiology of AKI. There are many trials leading to improved prevention and management of the disease.

Acute kidney injury after transcatheter aortic valve implantation with self-expanding CoreValve prosthesis: results from a large multicentre Italian research project

AIMS

Transcatheter aortic valve implantation (TAVI) can be associated with varying degrees of new renal impairment. The aim of this multicentre analysis was to determine the impact and predictors of periprocedural acute kidney injury (AKI) on prognosis after TAVI.

METHODS AND RESULTS

From the ClinicalService (a nation-based data repository and medical care project) dataset, 1,157 patients with severe aortic stenosis treated with the third-generation CoreValve prosthesis in seven Italian sites, and with creatinine data available at baseline and during the post-TAVI in-hospital course, were included in this analysis. All outcomes were defined according to the VARC criteria. Overall, AKI occurred in 231 (20.0%): 15.4% stage 1, 2.7% stage 2, and 1.9% stage 3. Compared to patients without AKI, patients who suffered post-procedural AKI had significantly higher three-year all-cause mortality (31% vs. 12%; adjusted HR: 2.09; 95% CI: 1.52-2.87, p<0.001) and cardiovascular mortality (14% vs. 6%; adjusted HR: 2.28; 95% CI: 1.41-3.71, p=0.001). No significant differences in terms of stroke, spontaneous MI, and bleeding were reported. Female gender (adjusted OR: 1.37, 95% CI: 1.01-1.87; p=0.045), baseline renal insufficiency (adjusted OR: 11.02, 95% CI: 5.12-23.73; p<0.001), general anaesthesia (adjusted OR: 1.37, 95% CI: 1.00-1.87; p=0.050), and transfusion ≥3 red blood cell (RBC) units within 72 hrs from TAVI (adjusted OR: 1.65, 95% CI: 1.02-2.68; p=0.041) were found to be independent predictors of AKI.

CONCLUSIONS

Acute kidney injury is a frequent complication and significantly impacts on both early and long-term TAVI survival. Females, subjects with impaired renal function at baseline, patients undergoing TAVI under general anaesthesia, and patients receiving ≥3 RBC units after the procedure should be considered populations at high risk for the development of AKI after TAVI.

Eliminating treatable deaths due to acute kidney injury in resource-poor settings

Acute kidney injury (AKI) is imposing a severe burden of morbidity and mortality both in developed and developing countries. Also AKI has a major economic impact on healthcare expenditure. This is particularly so in poor countries where AKI especially impacts young productive people, imposing severe penury upon their families. The mission is to lessen the high burden in terms of death consequent to this disorder in low-resource regions, which in many cases is preventable and treatable with simple measures. The International Society of Nephrology has launched a long-term program, called "0 by 25", which advocates that zero people should die of untreated AKI in the poorest part of Africa, Asia, and Latin America by 2025. This paper illustrates how the project will be developed.

The growth of acute kidney injury: a rising tide or just closer attention to detail?

Acute kidney injury (AKI), previously termed acute renal failure, is associated with increased mortality, prolonged hospital stay, and accelerated chronic kidney disease (CKD). Over the past 2 decades, dramatic rises in the incidences of AKI have been reported, particularly within the United States. The question arises as to whether these changes reflect actual increases in disease incidence, or are potentially explained by the introduction of consensus definitions that rely on small standardized changes in serum creatinine, changes in coding and reimbursement, or increasingly available and more liberal use of dialysis. In this review, we explore the secular trends in AKI incidence in North America and Western Europe and its potential contributors.

Hantavirus: an infectious cause of acute kidney injury in the UK

We present a case of an undifferentiated febrile illness in a 59-year-old man from East Yorkshire. He was initially treated for leptospirosis due to the fact that he had farm exposure and the findings of acute kidney injury (AKI), thrombocytopenia and a raised alanine transferase (ALT) on his initial blood results. Serology tests later proved him to have had another rodent-borne illness: hantavirus. An investigation by Public Health England (formerly known as Health Protection Agency) (PHE) went on to prove the presence of the same serotype of hantavirus in rats caught on the patient's property. After an initial deterioration, the patient made a relatively uneventful recovery and all his blood tests returned to normal levels.

Hypoxia-pretreated human MSCs attenuate acute kidney injury through enhanced angiogenic and antioxidative capacities

Hypoxia preconditioning has been confirmed as an effective strategy to enhance the therapeutic potentials of mesenchymal stem cells (MSCs), such as for myocardial ischemia. However, whether hypoxia preconditioning would produce beneficial effects on MSC-based renal repair has not been demonstrated. In the study, we aimed to determine the feasibility and efficacy of hypoxia preconditioning to enhance MSC-based therapy of acute kidney injury (AKI). MSCs were isolated from human adipose tissues. The paracrine effects of MSCs under normoxia and hypoxia were determined in vitro. Rats of AKI were induced by kidney I/R surgery and randomly divided into three groups: I/R control receiving PBS injection; MSC group receiving normal MSC injection; hypoMSC group receiving hypoxia-preconditioned MSC injection. It was demonstrated in vitro that paracrine effects of MSCs were significantly enhanced, especially angiogenic factors. Dihydroethidium (DHE) staining showed that antioxidative activities of MSCs were significantly enhanced by hypoxia stimulation. Vascularization, apoptosis, and histological injury were all significantly improved in hypoMSC injected group compared with that in control and MSC injected groups. Finally, the renal function was also significantly improved in hypoMSC injected group compared with that in the other two groups as assessed by the serum creatinine and BUN levels.

Socioeconomic factors and racial disparities in kidney disease outcomes

African Americans suffer disproportionately from advanced and progressive chronic kidney disease (CKD). Socioeconomic factors are believed to play an important role in this disparity, and likely influence African Americans' increased risk of CKD through multiple pathways. Low socioeconomic status (SES) may contribute to racial disparities in CKD because of the greater prevalence of poverty, for example, among African Americans as compared with whites. However, low SES has a stronger relation with CKD among African Americans than among whites, underscoring that the context and magnitude of socioeconomic influences on CKD outcomes varies between these populations. These socioeconomic influences may produce new or potentiate existing racial differences in biology. This review discusses what is known about the role of SES in explaining racial disparities in CKD, highlights several knowledge gaps in this area, and suggests future directions toward the elimination of disparities in CKD.

The impact of non-hilar clamping open partial technique performed for the treatment of patients with small renal masses with lower R.E.N.A.L. nephrometry scores on renal functions during the early postoperative period

OBJECTIVE

Herein, the impact of off-clamp open partial nephrectomy on early postoperative period renal functions were evaluated in patients with low RENAL nephrometry scoring small renal masses.

MATERIAL AND METHODS

Twenty-three patients (12 women, and 11 men) who had undergone non-hilar clamping open partial nephrectomy in our clinic between the years 2010, and 2013 were retrospectively evaluated. Mean age, body mass index (BMI), operative time, blood loss, renal nephrometry score, mean hospital stay, pre-, and postoperative serum creatinine (Cr), and glomerular filtration rate (GFR) of the patients were assessed.

RESULTS

Mean age, BMI, tumor size, and preoperative renal nephrometry scores were 56.09±10.49 years (36-70 yrs), 24.81±2.44 kg/m(2), 3.68±1.125 cm, and 6.41±1.77 pts, respectively. Mean operative time, intraoperative blood loss, and hospital stay were detected as 139.14±33.60 min, 274.9±77.02 mL, and 4.27±1.12 days, respectively. Preoperative mean serum Cr, and GFR levels were 0.804±0.216 mg/dL, and 93.97±25.83 mL/min/1.73 m(2), respectively. Postoperative 1. day mean serum Cr, and GFR levels were 0.896±0.25 mg/dL, and 85.94±28.85 mL/min/1,73 m(2), while corresponding 3. month-values were 0.81±0.205 mg/dL, and 93.59±21.00 mL/dk/1.73 m(2), respectively. A statistically significant difference was not found between preoperative, and postoperative 3. month- serum Cr, and GFR levels. However, postoperative 3. month-serum Cr, and GFR levels were lower than corresponding values estimated on postoperative 1. day (p<0.016).

CONCLUSION

One of the important considerations in partial nephrectomy is to preserve renal functions. Therefore, non-hilar clamping open partial nephrectomy should be taken into consideration for surgeons unexperienced especially in laparoscopic surgery with its lower morbidity, and complication rates.

IL-22 ameliorates renal ischemia-reperfusion injury by targeting proximal tubule epithelium

IL-22 is an epithelial cell survival cytokine that is currently under development for the treatment of acute liver damage. Here, we used a mouse model of renal ischemia/reperfusion (I/R) injury to investigate whether IL-22 has therapeutic potential for the treatment of AKI. The action of IL-22 is mediated by binding to IL-22R1 and leads to STAT3 activation. Under physiologic conditions, renal expression of IL-22R1 was detected only in the brush border of the renal proximal tubular epithelial cells (RPTECs). Renal I/R elevated serum IL-22 levels slightly but did not induce STAT3 phosphorylation in RPTECs. IL-22-deficient mice had slightly increased I/R-induced injury compared with wild-type mice. In contrast, treatment with IL-22 or overexpression of IL-22 by either gene targeting (IL-22 transgenic mice) or administration of adenovirus expressing IL-22 increased STAT3 phosphorylation in RPTECs, ameliorated I/R-induced renal inflammation and tubular cell injury, and preserved renal functions. Overexpression of IL-22 increased the phosphorylation of STAT3 and Akt, upregulated antiapoptotic genes (e.g., Bcl-2), and downregulated proapoptotic genes (e.g., Bad) in the kidneys of mice subjected to I/R. Notably, phosphorylation of Akt increased and expression of Bad decreased in proximal tubular cells under these conditions. Furthermore, compared with wild-type mice, IL-22 transgenic mice had increased survival rates, whereas IL-22-deficient mice had reduced survival rates after I/R injury. In summary, renal expression of IL-22R1 is restricted to RPTECs, and treatment with IL-22 protects against renal I/R injury by activating STAT3 and AKT, suggesting that IL-22 has therapeutic potential for the treatment of AKI.

Role of progesterone in melatonin-mediated protection against acute kidney injury

BACKGROUND

Melatonin is released by pineal gland and maintains circadian rhythm in the body. It has been reported as renoprotective agent because of its antioxidant property. Recently, a cross talk between progesterone and melatonin has been observed in various preclinical studies. The present study investigated the involvement of progesterone receptors in melatonin-mediated protection against ischemia reperfusion induced acute kidney injury (AKI) in rats.

MATERIALS AND METHODS

The rats were subjected to bilateral renal ischemia for 40 min followed by reperfusion for 24 h to induce AKI. The AKI was assessed by measuring creatinine clearance, serum urea, uric acid level, potassium level, fractional excretion of sodium, lactate dehydrogenase activity, and microproteinuria. The oxidative stress in renal tissues was assessed by quantification of myeloperoxidase activity, thiobarbituric acid reactive substances, superoxide anion generation, reduced glutathione level, and catalase activity. The hematoxylin-eosin staining was carried out to observe histopathologic changes in renal tissues. The melatonin (4 and 10 mg/kg, intraperitoneally) and progesterone receptor antagonist mifepristone (5 mg/kg, intraperitoneally) were used in the present study.

RESULTS

The renal ischemia reperfusion induced AKI as indicated by significant change in serum, urinary, and tissue parameters that was ameliorated by prior treatment with melatonin. No significant difference in serum progesterone level was observed between various groups used in the present study. The prior administration of mifepristone abolished melatonin-mediated protection against AKI.

CONCLUSIONS

It is concluded that melatonin treatment affords protection against ischemia reperfusion induced AKI. Moreover, progesterone receptors are essentially involved in mediating protective role of melatonin against AKI in rats.

Kidney regeneration: common themes from the embryo to the adult

The vertebrate kidney has an inherent ability to regenerate following acute damage. Successful regeneration of the injured kidney requires the rapid replacement of damaged tubular epithelial cells and reconstitution of normal tubular function. Identifying the cells that participate in the regeneration process as well as the molecular mechanisms involved may reveal therapeutic targets for the treatment of kidney disease. Renal regeneration is associated with the expression of genetic pathways that are necessary for kidney organogenesis, suggesting that the regenerating tubular epithelium may be "reprogrammed" to a less-differentiated, progenitor state. This review will highlight data from various vertebrate models supporting the hypothesis that nephrogenic genes are reactivated as part of the process of kidney regeneration following acute kidney injury (AKI). Emphasis will be placed on the reactivation of developmental pathways and how our understanding of the resulting regeneration process may be enhanced by lessons learned in the embryonic kidney.

Intermedin/adrenomedullin 2 protects against tubular cell hypoxia-reoxygenation injury in vitro by promoting cell proliferation and upregulating cyclin D1 expression

AIM

Intermedin/adrenomedullin 2 (IMD/ADM2) is a newly discovered peptide closely related to adrenomedullin. We recently reported that IMD/ADM2 gene transfer could significantly reduce renal ischaemia/reperfusion injury. In this study, we evaluated the effect of IMD/ADM2 on cell proliferation and regeneration in a cultured rat renal tubular epithelial cell line (NRK-52E) of hypoxia-reoxygenation (H/R) injury.

METHODS

The H/R model in NRK-52E cells consisted of hypoxia for 1 h and reoxygenation for 2 h. IMD/ADM2 was overexpressed in NRK-52E cells using the vector pcDNA3.1-IMD. Enzyme-linked immunosorbent assays were used to measure the concentration of IMD/ADM2 in the culture medium, and real-time PCR and Western blotting were used to determine mRNA and protein levels. In addition, luciferase reporter assays and electrophoretic mobility-shift assays were performed to measure cyclin D1 promoter activity and transcription factor activity.

RESULTS

We found that IMD/ADM2 gene transfer markedly promoted cell viability and decreased lactate dehydrogenase (LDH) activity and cell apoptosis compared with that of H/R. IMD/ADM2 increased the phosphorylation of ERK and decreased the phosphorylation of JNK and P38. Furthermore, IMD/ADM2 promoted cell cycle progression with concomitant increases in the levels of cyclin D1 and cyclin E, and these effects were blocked by the inhibition of ERK, or the agonist JNK and P38. IMD/ADM2 also increased cyclin D1 promoter activity and AP-1 DNA-binding activity.

CONCLUSIONS

We demonstrated that IMD/ADM2 promotes renal cell proliferation and regeneration after renal H/R injury by upregulating cyclin D1 and that this upregulation seems to be mediated by the ERK, JNK, and P38 MAPK signalling pathways.

Activation of the miR-17 family and miR-21 during murine kidney ischemia-reperfusion injury

BACKGROUND

Ischemia-reperfusion (I/R) is the main cause of acute kidney injury (AKI) in patients. We investigated renal microRNA (miRNA) expression profiles and the time course of changes in selected miRNA expressions after renal I/R to characterize the miRNA network activated during development and recovery from AKI.

METHODS AND RESULTS

One day after lethal (30 minutes) and sublethal (20 minutes) renal ischemia, AKI was verified by renal histology (tubular necrosis, regeneration), blood urea nitrogen (BUN) level, renal mRNA expression, and plasma concentration of neutrophil gelatinase-associated lipocalin (NGAL) in C57BL/6J mice. On the first day after 30-minute, lethal I/R miR-21, miR-17-5p, and miR-106a were elevated out of the 21 miRNAs successfully profiled on the Luminex multiplex assay. After 20-minute, sublethal I/R, renal miR-17-5p and miR-106a expressions were elevated on the first and second days of reperfusion, while miR-21 expression increased later and lasted longer. Renal miR-17-5p and miR-21 expressions correlated with each other. Renal function returned to normal on the fourth day after sublethal I/R.

CONCLUSIONS

Our results demonstrate that besides miR-21, miR-17-5p, and miR-106a are additionally activated during the maintenance and recovery phases of renal I/R injury. Furthermore, a correlation between renal miR-17-5p and miR-21 expressions warrants further investigation of how they may influence each other and the outcome of renal ischemia-reperfusion injury.

Heart-kidney crosstalk and role of humoral signaling in critical illness

Organ failure in the heart or kidney can initiate various complex metabolic, cell-mediated and humoral pathways affecting distant organs, contributing to the high therapeutic costs and significantly higher morbidity and mortality. The universal outreach of cells in an injured state has myriad consequences to distant organ cells and their milieu. Heart performance and kidney function are closely interconnected and communication between these organs occurs through a variety of bidirectional pathways. The term cardiorenal syndrome (CRS) is often used to describe this condition and represents an important model for exploring the pathophysiology of cardiac and renal dysfunction. Clinical evidence suggests that tissue injury in both acute kidney injury and heart failure has immune-mediated inflammatory consequences that can initiate remote organ dysfunction. Acute cardiorenal syndrome (CRS type 1) and acute renocardiac syndrome (CRS type 3) are particularly relevant in high-acuity medical units. This review briefly summarizes relevant research and focuses on the role of signaling in heart-kidney crosstalk in the critical care setting.

Acute kidney injury in the cancer patient

Acute kidney injury (AKI) is a frequent and significant complication of cancer and cancer therapy. Cancer patients frequently encounter risk factors for AKI including older age, CKD, prerenal conditions, sepsis, exposure to nephrotoxins, and obstructive physiology. AKI can also be secondary to paraneoplastic conditions, including glomerulonephritis and microangiopathic processes. This complication can have significant consequences, including effects on patients' ability to continue to receive therapy for their malignancy. This review will serve to summarize potential etiologies of AKI that present in patients with cancer as well as to highlight specific patient populations, such as the critically ill cancer patient.

MicroRNA-21 in the pathogenesis of acute kidney injury

Acute kidney injury (AKI), associated with significant morbidity and mortality, is widely known to involve epithelial apoptosis, excessive inflammation, and fibrosis in response to ischemia or reperfusion injury, which results in either chronic pathological changes or death. Therefore, it is imperative that investigations are conducted in order to find effective, early diagnoses, and therapeutic targets needed to help prevent and treat AKI. However, the mechanisms modulating the pathogenesis of AKI still remain largely undetermined. MicroRNAs (miRNAs), small non-coding RNA molecules, play an important role in several fundamental biological and pathological processes by a post transcriptional regulatory function of gene expression. MicroRNA-21 (miR-21) is a recently identified, typical miRNA that is functional as a regulator known to be involved in apoptosis as well as inflammatory and fibrotic signaling pathways in AKI. As a result, miR-21 is now considered a novel biomarker when diagnosing and treating AKI. This article reviews the correlative literature and research progress regarding the roles of miR-21 in AKI.

Evaluation of 32 urine biomarkers to predict the progression of acute kidney injury after cardiac surgery

Biomarkers for acute kidney injury (AKI) have been used to predict the progression of AKI but a systematic comparison of the prognostic ability of each biomarkers alone or in combination has not been performed. In order to assess this, we measured the concentration of 32 candidate biomarkers in the urine of 95 patients with AKIN stage 1 after cardiac surgery. Urine markers were divided into eight groups based on the putative pathophysiologic mechanism they reflect. We then compared the ability of the markers alone or in combination to predict the primary outcome of worsening AKI or death (23 patients) and the secondary outcome of AKIN stage 3 or death (13 patients). IL-18 was the best predictor of both outcomes (AUC of 0.74 and 0.89). L-FABP (AUC of 0.67 and 0.85), NGAL (AUC of 0.72 and 0.83) and KIM-1 (AUC of 0.73 and 0.81) were also good predictors. Correlation between most of the markers was generally related to their predictive ability but KIM-1 had a relatively weak correlation with other markers. The combination of IL-18 and KIM-1 had a very good predictive value with an AUC of 0.93 to predict AKIN 3 or death. Thus, combination of IL-18 and KIM-1 would result in improved identification of high risk patients for enrollment in clinical trials.

Raising awareness of acute kidney injury: a global perspective of a silent killer

Worldwide, acute kidney injury (AKI) is associated with poor patient outcomes. Over the last few years, collaborative efforts, enabled by a common definition of AKI, have provided a description of the epidemiology, natural history, and outcomes of this disease and improved our understanding of the pathophysiology. There is increased recognition that AKI is encountered in multiple settings and in all age groups, and that its course and outcomes are influenced by the severity and duration of the event. The effect of AKI on an individual patient and the resulting societal burden that ensues from the long-term effects of the disease, including development of chronic kidney disease (CKD) and end-stage renal disease (ESRD), is attracting increasing scrutiny. There is evidence of marked variation in the management of AKI, which is, to a large extent, due to a lack of awareness and an absence of standards for prevention, early recognition, and intervention. These emerging data point to an urgent need for a global effort to highlight that AKI is preventable, its course is modifiable, and its treatment can improve outcomes. In this article, we provide a framework of reference and propose specific strategies to raise awareness of AKI globally, with the goal to ultimately improve outcomes from this devastating disease.

Etiology and outcomes of acute kidney injury in Chinese children: a prospective multicentre investigation

Background

The incidence of AKI appears to have increasing trend. Up to now, prospective, multi-center, large-sample epidemiological study done on pediatric AKI on aspects of epidemiological characteristics, causes and outcomes have not reported. It is necessary to develop prospective, multi-center, large-sample epidemiological study in our country on pediatric AKI. The aim of this study was to determine the clinical features, etiology, and outcomes of acute kidney injury (AKI) in Chinese children.

Method

Paediatric patients (≤18 years old) admitted to 27 hospitals (14 children’s hospitals and 13 general hospitals) affiliated with the Medical University were investigated. AKI was defined using the 2005 Acute Kidney Injury Network criteria.

Results

During the study period, 388,736 paediatric patients were admitted. From this total, AKI was diagnosed in 1,257 patients, 43 of whom died. The incidence and mortality of AKI was 0.32% and 3.4% respectively. The mean (± SD) age of patients was 48.4 ± 50.4 months. Among the 1,257 AKI paediatric patients, 632 were less than one year old. Among the AKI paediatric patients, 615 (48.9%) were in stage 1, 277 (22.0%) in stage 2, and 365 (29.0%) in stage 3. The most common causes of AKI were renal causes (57.52%), whereas postrenal (25.69%) and prerenal (14.96%) causes were the least common. The three most common causes of AKI according to individual etiological disease were urolithiasis (22.35%), of which exposure to melamine-contaminated milk accounted for the highest incidence (63.7%); acute glomerulonephritis (10.10%); and severe dehydration (7.48%). A total of 43 AKI patients (3.4%) died during their hospital stay; 15 (34.9%) of the 43 died as a result of sepsis.

Conclusion

Primary renal diseases are a major risk factor for paediatric AKI in China. In terms of specific etiological disease, urolithiasis (postrenal disease) was the leading cause of paediatric AKI in 2008, when the disease was linked to exposure to melamine-contaminated milk. Sepsis is the leading cause of death in Chinese paediatric AKI patients. Future studies should focus on effective ways of controlling renal disorders and sepsis to improve the clinical management of paediatric AKI in China.

Survivin mediates renal proximal tubule recovery from AKI

AKI induces the renoprotective upregulation of survivin expression in kidney epithelial cells, but the underlying mechanisms have not been identified. To determine the role of survivin in renal recovery from AKI, we generated mice with renal proximal tubule-specific deletion of survivin (survivin(ptKO)). Renal survivin expression increased substantially in response to ischemia-reperfusion (I/R) injury in control littermates but remained minimal in survivin(ptKO) mice. Functional and histologic data indicated similar degrees of renal injury in survivin(ptKO) and control mice 24 hours after reperfusion, but recovery was markedly delayed in survivin(ptKO) mice. In MCT cells, a mouse renal proximal tubule cell line, ATP depletion by antimycin A treatment upregulated survivin expression through a phospho-STAT3-dependent pathway. In wild-type mice, inhibition of STAT3 kinase diminished I/R-induced upregulation of STAT3 phosphorylation and survivin expression and delayed recovery. Furthermore, I/R injury activated Notch-2 signaling, and a γ-secretase inhibitor suppressed I/R-induced Notch-2 signaling, STAT3 phosphorylation, and survivin expression and delayed recovery. In MCT cells, inhibition of γ-secretase similarly attenuated antimycin A-induced Notch-2 activation, upregulation of survivin, and phosphorylation of STAT3, but STAT3 kinase inhibition did not prevent Notch-2 activation. Therefore, these data suggest that STAT3 phosphorylation and subsequent upregulation of survivin expression mediated by Notch-2 signaling in renal proximal tubule epithelial cells aid in the functional and structural recovery of the kidney from AKI.

Practical considerations for the dosing and adjustment of continuous renal replacement therapy in the intensive care unit

Familiarity with the initiation, dosing, adjustment, and termination of continuous renal replacement therapy (CRRT) is a core skill for contemporary intensivists. Guidelines for how to administer CRRT in the intensive care unit are not well documented. The purpose of this review is to discuss the modalities, terminology, and components of CRRT, with an emphasis on the practical aspects of dosing, adjustments, and termination. Management of electrolyte and acid-base derangements commonly encountered with acute renal failure is emphasized. Knowledge regarding the practical aspects of managing CRRT in the intensive care unit is a prerequisite for achieving desired physiological end points.

Use of peritoneal dialysis in AKI: a systematic review

BACKGROUND AND OBJECTIVES

The role of peritoneal dialysis in the management of AKI is not well defined, although it remains frequently used, especially in low-resource settings. A systematic review was performed to describe outcomes in AKI treated with peritoneal dialysis and compare peritoneal dialysis with extracorporeal blood purification, such as continuous or intermittent hemodialysis.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

MEDLINE, CINAHL, and Central Register of Controlled Trials were searched in July of 2012. Eligible studies selected were observational cohort or randomized adult population studies on peritoneal dialysis in the setting of AKI. The primary outcome of interest was all-cause mortality. Summary estimates of odds ratio were obtained using a random effects model.

RESULTS

Of 982 citations, 24 studies (n=1556 patients) were identified. The overall methodological quality was low. Thirteen studies described patients (n=597) treated with peritoneal dialysis only; pooled mortality was 39.3%. In 11 studies (7 cohort studies and 4 randomized trials), patients received peritoneal dialysis (n=392, pooled mortality=58.0%) or extracorporeal blood purification (n=567, pooled mortality=56.1%). In the cohort studies, there was no difference in mortality between peritoneal dialysis and extracorporeal blood purification (odds ratio, 0.96; 95% confidence interval, 0.53 to 1.71). In four randomized trials, there was also no difference in mortality (odds ratio, 1.50; 95% confidence interval, 0.46 to 4.86); however, heterogeneity was significant (I(2)=73%, P=0.03).

CONCLUSIONS

There is currently no evidence to suggest significant differences in mortality between peritoneal dialysis and extracorporeal blood purification in AKI. There is a need for good-quality evidence in this important area.

Plasma neutrophil gelatinase-associated lipocalin as a biomarker for acute kidney injury in critically ill patients with suspected sepsis

OBJECTIVES

The aim of this study was to investigate the diagnostic utility of plasma neutrophil gelatinase-associated lipocalin (NGAL) as an early objective biomarker to predict acute kidney injury (AKI) in critically ill patients with suspected sepsis, for whom procalcitonin (PCT) was used for the diagnosis and staging of sepsis.

DESIGN AND METHODS

Plasma NGAL was measured using the Triage NGAL Test (Alere, Inc., San Diego, CA, USA) in 231 samples obtained from patients with suspected sepsis. The results of NGAL were compared with those of Elecsys BRAHMS PCT (Roche Diagnostics, Basel, Switzerland). Renal failure was assessed using the renal subscore of Sepsis-related Organ Failure Assessment (SOFA) score. AKI was defined according to the Acute Kidney Injury Network criteria.

RESULTS

The concentrations of plasma NGAL were significantly different according to the five groups of PCT concentration (P<0.0001) and the renal subscore of SOFA score (P<0.0001). Plasma NGAL was significantly increased in the patients with AKI compared with those without AKI (416.5 ng/mL vs. 181.0 ng/mL, P=0.0223).

CONCLUSION

Plasma NGAL seems to be a highly sensitive and objective predictor of AKI in patients with sepsis. Plasma NGAL can be added for the diagnosis and staging of renal failure in sepsis.

Long-term outcome of cats and dogs with acute kidney injury treated with intermittent hemodialysis: 135 cases (1997-2010)

OBJECTIVE

To determine the long-term outcome for small animal patients with acute kidney injury (AKI) treated with intermittent hemodialysis (IHD).

DESIGN

Retrospective case series.

ANIMALS

42 cats and 93 dogs treated with IHD for AKI.

PROCEDURES

Medical records of cats and dogs treated with IHD for AKI from January 1997 to October 2010 were reviewed. Standard methods of survival analysis with Kaplan-Meier product limit curves were used. The log-rank, Mann-Whitney, and Kruskal-Wallis tests were used to determine whether outcome, number of IHD treatments, or duration of hospitalization was different when dogs and cats were classified according to specific variables.

RESULTS

The overall survival rate at the time of hospital discharge was 50% (21/42) for cats and 53% (49/93) for dogs. The overall survival rate 30 days after hospital discharge was 48% (20/42) for cats and 42% (39/93) for dogs. The overall survival rate 365 days after hospital discharge was 38% (16/42) for cats and 33% (31/93) for dogs. For all-cause mortality, the median survival time was 7 days (95% confidence interval, 0 to 835 days) for cats and 9 days (95% confidence interval, 0 to 55 days) for dogs.

CONCLUSIONS AND CLINICAL RELEVANCE

Cats and dogs with AKI treated with IHD have survival rates similar to those of human patients. Although there was a high mortality rate prior to hospital discharge, those patients that survived to discharge had a high probability of long-term survival.

Histone deacetylase inhibitor enhances recovery after AKI

At present, there are no effective therapies to ameliorate injury, accelerate recovery, or prevent postinjury fibrosis after AKI. Here, we sought to identify candidate compounds that accelerate recovery after AKI by screening for small molecules that increase proliferation of renal progenitor cells in zebrafish embryos. One compound identified from this screen was the histone deacetylase inhibitor methyl-4-(phenylthio)butanoate, which we subsequently administered to zebrafish larvae and mice 24-48 hours after inducing AKI. In zebrafish, treatment with the compound increased larval survival and proliferation of renal tubular epithelial cells. In mice, treatment accelerated recovery, reduced postinjury tubular atrophy and interstitial fibrosis, and increased the regenerative capacity of actively cycling renal tubular cells by decreasing the number of cells in G2/M arrest. These data suggest that accelerating recovery may be a viable approach to treating AKI and provide proof of concept that a screen in zebrafish embryos can identify therapeutic candidates for kidney injury.