Long-term remote organ consequences following acute kidney injury

Cardiac damage following renal ischemia reperfusion injury increased with excessive consumption of high fat diet but enhanced the cardiac resistance to reperfusion stress in rat

Renal ischemia-reperfusion (IR) injury inflicts remote cardiac dysfunction. Studies on rats fed with a high-fat diet (HD) showed contradictory results: some demonstrated increased sensitivity of the heart and kidney to IR injury, while others reported resistance. In this study, we examined cardiac dysfunction and compromised cardiac tolerance associated with renal IR in HD and standard diet (SD) fed rats. Male Wistar rats fed with HD or SD diet for 16 weeks were subjected to either renal sham or IR protocol (bilateral clamping for 45 min and reperfusion for 24 h). The hearts isolated from these rats were further subjected to normal perfusion or IR procedure to study cardiac response. Renal IR surgery negatively affected cardiac function with substantial changes in the cardiac tissues, like mitochondrial dysfunction, elevated oxidative stress, and inflammation. HD-fed rat hearts exhibited hypertrophy at the end of 16 weeks, and the consequential impact on the heart was higher in the animals underwent renal IR surgery than with sham surgery. However, the IR induction in the isolated heart from renal sham or renal IR operation showed significant tissue injury resistance and better physiological recovery in HD-fed rats. However, in SD-fed rats, only hearts from renal IR-operated rats showed resistance to cardiac IR, whereas hearts from renal sham-operated rats were more susceptible to IR damage. The augmented IR resistance in the heart with prior renal surgery was due to preserved mitochondrial bioenergetics function, reduced oxidative stress, and activation of the PI3K/AKT signaling axis.

Impaired microvascular circulation in distant organs following renal ischemia

Mortality in acute kidney injury (AKI) patients remains very high, although very important advances in understanding the pathophysiology and in diagnosis and supportive care have been made. Most commonly, adverse outcomes are related to extra-renal organ dysfunction and failure. We and others have documented inflammation in remote organs as well as microvascular dysfunction in the kidney after renal ischemia. We hypothesized that abnormal microvascular flow in AKI extends to distant organs. To test this hypothesis, we employed intravital multiphoton fluorescence imaging in a well-characterized rat model of renal ischemia/reperfusion. Marked abnormalities in microvascular flow were seen in every organ evaluated, with decreases up to 46% observed 48 hours postischemia (as compared to sham surgery, p = 0.002). Decreased microvascular plasma flow was found in areas of erythrocyte aggregation and leukocyte adherence to endothelia. Intravital microscopy allowed the characterization of the erythrocyte formations as rouleaux that flowed as one-dimensional aggregates. Observed microvascular abnormalities were associated with significantly elevated fibrinogen levels. Plasma flow within capillaries as well as microthrombi, but not adherent leukocytes, were significantly improved by treatment with the platelet aggregation inhibitor dipyridamole. These microvascular defects may, in part, explain known distant organ dysfunction associated with renal ischemia. The results of these studies are relevant to human acute kidney injury.

Cardiac effects of renal ischemia

Mortality in acute kidney injury (AKI) remains very high, yet the cause of death is often failure of extrarenal organs. We and others have demonstrated remote organ dysfunction after renal ischemia. The term "cardiorenal syndrome" was first applied to the "cross talk" between the organs by the National Heart, Lung, and Blood Institute of the National Institutes of Health, and the clinical importance is being increasingly appreciated. Nevertheless, more information is needed to effectively address the consequences of renal injury on the heart. Since AKI often occurs in patients with comorbidities, we investigated the effect of renal ischemia in the setting of existing cardiac failure. We hypothesized that the cardiac effects of renal ischemia would be significantly amplified in experimental cardiomyopathy. Male Sprague-Dawley rats with preexisting cardiac and renal injury due to low-dose doxorubicin were subjected to bilateral renal artery occlusion. Cardiac structure and function were examined 2 days after reperfusion. Loss of functional myocardial tissue with decreases in left ventricular pressure, increases in apoptotic cell death, inflammation, and collagen, and greater disruption in ultrastructure with mitochondrial fragmentation were seen in the doxorubicin/ischemia group compared with animals in the groups treated with doxorubicin alone or following ischemia alone. Systemic inflammation and cardiac abnormalities persisted for at least 21 wk. These results suggest that preexisting comorbidities can result in much more severe distant organ effects of acute renal injury. The results of this study are relevant to human AKI.NEW & NOTEWORTHY Acute kidney injury is common, expensive, and deadly, yet morbidity and mortality are often secondary to remote organ dysfunction. We hypothesized that the effects of renal ischemia would be amplified in the setting of comorbidities. Sustained systemic inflammation and loss of functional myocardium with significantly decreased systolic and diastolic function, apoptotic cell death, and increased collagen and inflammatory cells were found in the heart after renal ischemia in the doxorubicin cardiomyopathy model (vs. renal ischemia alone). Understanding the remote effects of renal ischemia has the potential to improve outcomes in acute kidney injury.

Acute Kidney Injury and Diastolic Dysfunction: Opportunity for Targeted Intervention?

BACKGROUND/AIMS

Acute kidney injury (AKI) is common, results in nonrenal sequelae, and predisposes patients to long-term cardiovascular disease. The long-term systemic effects of AKI remain unclear. Sex is an important biological variable in ischemia-reperfusion AKI, and the protective role of estrogen has stymied the inclusion of both sexes in preclinical AKI studies. ITF2357 is a nonspecific histone deacetylase inhibitor that has been shown to improve cardiac outcomes in murine models of hypertension. Here, we review recent work that provides new insight into our understanding of cardiovascular sequelae following AKI.

METHODS

Adult male and female C57BL/6J mice underwent 25 min (males) and 34 min (females) of bilateral ischemia-reperfusion AKI or sham procedure. A male treatment arm received chow containing the nonspecific histone deacetylase inhibitor ITF2357 starting 3 days after AKI. Serial renal function, echocardiograms, and blood pressure assessments were performed throughout the 1-year study; renal histology and cardiac and plasma metabolomics were evaluated at 1 year.

RESULTS

Measured glomerular filtration rates throughout the 1-year study showed that the female model of AKI matched the male model. Untreated males developed depressed diastolic function after AKI, whereas females and males treated with ITF2357 maintained normal diastolic function. Both untreated males and females developed hypertension after AKI; males treated with ITF2357 remained normotensive.

CONCLUSIONS

Ischemic AKI results in long-term cardiovascular sequelae with sex as an important biological variable in outcomes. Histone deacetylase inhibition affects cardiovascular outcomes after AKI.

Myeloid CCR2 Promotes Atherosclerosis after AKI

BACKGROUND

The risk of cardiovascular events rises after AKI. Leukocytes promote atherosclerotic plaque growth and instability. We established a model of enhanced remote atherosclerosis after renal ischemia-reperfusion (IR) injury and investigated the underlying inflammatory mechanisms.

METHODS

Atherosclerotic lesions and inflammation were investigated in native and bone marrow-transplanted LDL receptor-deficient (LDLr^-/- ) mice after unilateral renal IR injury using histology, flow cytometry, and gene expression analysis.

RESULTS

Aortic root atherosclerotic lesions were significantly larger after renal IR injury than in controls. A gene expression screen revealed enrichment for chemokines and their cognate receptors in aortas of IR-injured mice in early atherosclerosis, and of T cell-associated genes in advanced disease. Confocal microscopy revealed increased aortic macrophage proximity to T cells. Differential aortic inflammatory gene regulation in IR-injured mice largely paralleled the pattern in the injured kidney. Single-cell analysis identified renal cell types that produced soluble mediators upregulated in the atherosclerotic aorta. The analysis revealed a marked early increase in Ccl2, which CCR2⁺ myeloid cells mainly expressed. CCR2 mediated myeloid cell homing to the post-ischemic kidney in a cell-individual manner. Reconstitution with Ccr2^-/- bone marrow dampened renal post-ischemic inflammation, reduced aortic Ccl2 and inflammatory macrophage marker CD11c, and abrogated excess aortic atherosclerotic plaque formation after renal IR.

CONCLUSIONS

Our data introduce an experimental model of remote proatherogenic effects of renal IR and delineate myeloid CCR2 signaling as a mechanistic requirement. Monocytes should be considered as mobile mediators when addressing systemic vascular sequelae of kidney injury.

Thymic and Peripheral T-cell Polarization in an Experimental Model of Russell's Viper Venom-induced Acute Kidney Injury

Venom pathology is not restricted to the direct toxic effects of venom. Immunoinflammatory alteration as the etiology of snake venom-induced acute kidney injury (SAKI) is a less trodden path toward the development of alternative therapeutic approach. In the present study, we have associated the crest of renal damage stage to the immunological alteration, as reflected in thymic and peripheral T cell polarization in the murine model of SAKI. Renal injury in mice was confirmed from significant dysuresis and adversely altered biochemical renal markers. Histopathological alterations, as revealed by marked tubular and glomerular damage, reaffirmed kidney injury. SAKI is accompanied by significant inflammatory changes as indicated by neutrophilic leucocytosis, increased neutrophil to lymphocyte ratio and plasma CRP levels. Thymic immunophenotyping revealed significantly increased CD8+ cytotoxic T cell, and CD25+ both single positive population (p = .017-0.010) and CD44-CD25+ double negative population (DN3) (p = .002) accompanied by an insignificantly reduced CD4+ helper T cells (p = .451). Peripheral immunophenotyping revealed similar pattern as indicated by reduced helper T cells (p = .002) associated with significantly elevated cytotoxic T cells (p = .009) and CD25+ subset of both helper (p = .002) and cytotoxic (p = .024) T cells. The IL-10+ subset of both CD25+ and CD25- T cells were also found to be significantly elevated in the SAKI group (p ≤ 0.020) suggesting an immunosuppressive phenotype in SAKI. It can be concluded that T cells responds to venom-induced renal injury particularly through IL-10+ reparative phenotypes which are known for their immunosuppressive and anti-inflammatory activity.

Acute Kidney Injury and Gut Dysbiosis: A Narrative Review Focus on Pathophysiology and Treatment

Acute kidney injury (AKI) and gut dysbiosis affect each other bidirectionally. AKI induces microbiota alteration in the gastrointestinal (GI) system, while gut dysbiosis also aggravates AKI. The interplay between AKI and gut dysbiosis is not yet well clarified but worthy of further investigation. The current review focuses on the pathophysiology of this bidirectional interplay and AKI treatment in this base. Both macrophages and neutrophils of the innate immunity and the T helper type 17 cell from the adaptive immunity are the critical players of AKI-induced gut dysbiosis. Conversely, dysbiosis-induced overproduction of gut-derived uremic toxins and insufficient generation of short-chain fatty acids are the main factors deteriorating AKI. Many novel treatments are proposed to deter AKI progression by reforming the GI microbiome and breaking this vicious cycle. Data support the benefits of probiotic treatment in AKI patients, while the results of postbiotics are mainly limited to animals. Prebiotics and synbiotics are primarily discussed in chronic kidney disease patients rather than AKI patients. The effect of adsorbent treatment seems promising, but more studies are required before the treatment can be applied to patients. Immune therapy and some repurposed drugs such as allopurinol are prospects of future treatments and are worth more discussion and survey.

Effect of continuous hemofiltration on severe acute pancreatitis with different intra-abdominal pressure: A cohort study

BACKGROUND

The clinical efficacy and timing of continuous veno-venous hemofiltration (CVVH) in the treatment of severe acute pancreatitis (SAP) remain uncertain. In this prospective cohort study, patients with SAP were classified according to intra-abdominal pressure (IAP).

METHODS

Seventy-four patients with SAP admitted to the intensive care unit were randomly divided into group A (IAP ≥20 mm Hg) and group B (with IAP ≤20 mm Hg). Then, according to whether CVVH was administered or not, groups A and B were divided into 4 subgroups: group A1 and B1 (non-CVVH treatment), group A2 and B2 (CVVH treatment). Changes in clinical and laboratory indicators were recorded before and on the seventh day after treatment, and clinical outcomes were analyzed.

RESULTS

Before treatment, there was no significant difference in general conditions between subgroups A1 and A2, and between subgroups B1 and B2. After CVVH treatment, the indicators recorded in group A2 were significantly improved compared to those in group A1 (P < .05). In group A2, the 28 day operation rate was lower (P < .05), as mechanical ventilation, gastric decompression, and intensive care unit treatment time were shorter (P < .05). However, there was no statistically significant difference in any of the above indicators between subgroups B (P > .05). Groups A2 and B2 had more days of negative fluid balance within 1 week of admission than groups A1 and B1 (P < .05).

CONCLUSIONS

For SAP, patients with IAP ≥20 mm Hg can benefit from treatment with CVVH, but for patients with IAP ≤20 mm Hg, the efficacy is not clear, and monitoring IAP may be an indicator to decide whether or when to initiate CVVH. Negative fluid balance caused by CVVH treatment may be one of the reasons for the benefit of this group of patients.

Identifying neurocognitive outcomes and cerebral oxygenation in critically ill adults on acute kidney replacement therapy in the intensive care unit: the INCOGNITO-AKI study protocol

INTRODUCTION

Initiation of acute kidney replacement therapy (KRT) is common in critically ill adults admitted to the intensive care unit (ICU), and associated with increased morbidity and mortality. KRT has been linked to poor neurocognitive outcomes, leading to reduced quality of life and increased utilisation of healthcare resources. Adults on dialysis in the ICU may be particularly at risk of neurocognitive impairment, as survivors of critical illness are already predisposed to developing cerebrovascular disease and cognitive dysfunction long-term relative to healthy controls. Regional cerebral oxygen saturation may provide a critical early marker of long-term neurocognitive impairment in this population. This study aims to understand cerebral oxygenation in patients undergoing KRT (continuous or intermittent) in the ICU. These findings will be correlated with long-term cognitive and functional outcomes, and structural brain pathology.

METHODS AND ANALYSIS

108 patients scheduled to undergo treatment for acute kidney injury with KRT in the Kingston Health Sciences Centre ICU will be recruited into this prospective observational study. Enrolled patients will be assessed with intradialytic cerebral oximetry using near infrared spectroscopy. Delirium will be assessed daily with the Confusion Assessment Method-ICU (CAM-ICU) and severity quantified as cumulative CAM-ICU-7 scores. Neurocognitive impairment will be assessed at 3 and 12 months after hospital discharge using the Kinarm and Repeatable Battery for the Assessment of Neuropsychological Status. Structural brain pathology on MRI will also be measured at the same timepoints. Driving safety, adverse events and medication adherence will be assessed at 12 months to evaluate the impact of neurocognitive impairment on functional outcomes.

ETHICS AND DISSEMINATION

This study is approved by the Queen's University Health Sciences/Affiliated Teaching Hospitals Research Ethics Board (DMED-2424-20). Results will be presented at critical care conferences, and a lay summary will be provided to patients in their preferred format.

TRIAL REGISTRATION NUMBER

NCT04722939.

Acute Kidney Injury and Organ Dysfunction: What Is the Role of Uremic Toxins?

Acute kidney injury (AKI), defined as an abrupt increase in serum creatinine, a reduced urinary output, or both, is experiencing considerable evolution in terms of our understanding of the pathophysiological mechanisms and its impact on other organs. Oxidative stress and reactive oxygen species (ROS) are main contributors to organ dysfunction in AKI, but they are not alone. The precise mechanisms behind multi-organ dysfunction are not yet fully accounted for. The building up of uremic toxins specific to AKI might be a plausible explanation for these disturbances. However, controversies have arisen around their effects in organs other than the kidney, because animal models usually depict AKI as a kidney-specific injury. Meanwhile, humans present AKI frequently in association with multi-organ failure (MOF). Until now, medium-molecular-weight molecules, such as inflammatory cytokines, have been proven to play a role in endothelial and epithelial injury, leading to increased permeability and capillary leakage, mainly in pulmonary and intestinal tissues.

Risk and consequences of dehydration following colorectal cancer resection with diverting ileostomy. A systematic review and meta-analysis

AIM

This systematic review aims to assess dehydration prevalence and dehydration-related morbidity from diverting ileostomy compared to resections without ileostomy formation in adults undergoing colorectal resection for cancer.

METHOD

MEDLINE, Embase, CENTRAL and ClinicalTrials.gov were searched for studies of any design that reported dehydration, renal function and dehydration-related morbidity in adult colorectal cancer patients with diverting ileostomy (last search 12 August 2020). Bias was assessed using the Cochrane Collaboration's tool for assessing risk of bias in randomized trials and the Risk of Bias in Non-randomized Studies of Interventions tool.

RESULTS

Of 1927 screened papers, 22 studies were included (21 cohort studies and one randomized trial) with a total of 19 485 patients (12 209 with ileostomy). The prevalence of dehydration was 9.00% (95% CI 5.31-13.45, P < 0.001). The relative risk of dehydration following diverting ileostomy was 3.37 (95% CI 2.30-4.95, P < 0.001). Three studies assessing long-term trends in renal function demonstrated progressive renal impairment persisting beyond the initial insult. Consequences identified included unplanned readmission, delay or non-commencement of adjuvant chemotherapy, and development of chronic kidney disease.

DISCUSSION

Significant dehydration is common following diverting ileostomy; it is linked to acute kidney injury and has a long-term impact on renal function. This study suggests that ileostomy confers significant morbidity particularly related to dehydration and renal impairment.

Long-term outcomes following vehicle trauma related acute kidney injury requiring renal replacement therapy: a nationwide population study

Acute kidney injury (AKI) is a frequent complication of traumatic injury; however, long-term outcomes such as mortality and end-stage kidney disease (ESKD) have been rarely reported in this important patient population. We compared the long-term outcome of vehicle-traumatic and non-traumatic AKI requiring renal replacement therapy (AKI-RRT). This nationwide cohort study used data from the Taiwan National Health Insurance Research Database. Vehicle-trauma patients who were suffered from vehicle accidents developing AKI-RRT during hospitalization were identified, and matching non-traumatic AKI-RRT patients were identified between 2000 and 2010. The incidences of ESKD, 30-day, and long-term mortality were evaluated, and clinical and demographic associations with these outcomes were identified using Cox proportional hazards regression models. 546 vehicle-traumatic AKI-RRT patients, median age 47.6 years (interquartile range: 29.0–64.3) and 76.4% male, were identified. Compared to non-traumatic AKI-RRT, vehicle-traumatic AKI-RRT patients had longer length of stay in hospital [median (IQR):15 (5–34) days vs. 6 (3–11) days; p < 0.001). After propensity matching with non-traumatic AKI-RRT cases with similar demographic and clinical characteristics. Vehicle-traumatic AKI-RRT patients had lower rates of long-term mortality (adjusted hazard ratio (HR), 0.473; 95% CI, 0.392–0.571; p < 0.001), but similar rates of ESKD (HR, 1.166; 95% CI, 0.829–1.638; p = 0.377) and short-term risk of death (HR, 1.134; 95% CI, 0.894–1.438; p = 0.301) as non-traumatic AKI-RRT patients. In competing risk models that focused on ESKD, vehicle-traumatic AKI-RRT patients were associated with lower ESKD rates (HR, 0.552; 95% CI, 0.325–0.937; p = 0.028) than non-traumatic AKI-RRT patients. Despite severe injuries, vehicle-traumatic AKI-RRT patients had better long-term survival than non-traumatic AKI-RRT patients, but a similar risk of ESKD. Our results provide a better understanding of long-term outcomes after vehicle-traumatic AKI-RRT.

Quality assessment of unsaturated iron-binding protein capacity in Iraqi patients undergoing hemodialysis

Hemodialysis is autoimmune disease result from inflammation, oxidative stress, and fibrosis. It is characterized by renal glomeruli damage, podocyte injury, tubule interstitial, and proteinuria. Electrolyte balance is the main function of the renal and any form of electrolyte disorders may lead to excess blood volume, hypertension, and difficulty in maintaining natural blood sodium. Renal erythropoietin has an important role in the balance of vascular active substances, such as prostaglandins and thromboxanes; therefore, patients undergoing hemodialysis observe decreased production of erythropoietin with iron loss through hemodialysis machine as well as weakened iron absorption and mobilization from the intestine to the bloodstream. Ferritin, total iron-binding capacity (TIBC), unsaturated iron-binding protein capacity (UIBC), iron free, and transferrin are used to confirm iron status. According the clinical characterization of the results, no normality was observed in patients undergoing hemodialysis. There was hypertension, anemia, lean symptoms and equal distribution of age parallel with developed disease, there was significant increased in renal function except albumin, it was decreased in the patients compared with control groups. In addition, there was a decreased level of iron status in all parameters such as packed cell volume (%), TIBC, UIBC, iron free, and transferrin except ferritin; there was an increased level of iron status in all parameters in patients compared with control groups.

Optimal timing of renal replacement therapy for favourable outcome in patients of acute renal failure following cardiac surgery

Objectives

Acute renal failure is a serious complication following cardiac surgery. This may lead to fatal outcome if not treated timely. Continuous renal replacement therapy (RRT) has shown improvement in outcome. There is no clear consensus on the timing of the initiation of RRT in these patients. This study evaluates the factors predicting favourable outcome in this group of patients.

Methods

Patients undergoing cardiac surgery between January 2015 and December 2018 are included in this retrospective study. RRT is required in 24 patients out of 2254 operated during this period. Patients are divided into groups, survivors (group 1, n = 8) and dead (group 2, n = 16). The preoperative information is accessed from the hospital information system and intensive care unit data. Multivariate analysis of pre continuous renal replacement therapy (CRRT) bicarbonate level, pH, potassium, time of initiating CRRT and central venous pressure is performed.

Results

The incidence of acute renal failure requiring RRT is 1.06%. Patients in two groups were similar in demographics and presence of risk factors. There was difference in the pre RRT bicarbonate level (p = 0.007). On multivariate analysis, pre RRT bicarbonate levels predict survival (p = 0.003). ROC curve for pre RRT bicarbonate predicts survival for value above 16.83 mg/dl with 80% sensitivity and 78.6% specificity.

Conclusion

Bicarbonate level in blood predicts the best evidence for initiating the renal replacement therapy in of acute renal failure following cardiac surgery. When urine output drops to < 0.5 ml/kg and not responding to infusion of furosemide, RRT must be initiated at sodium bicarbonate in blood above 16.9 mg%.

Effects of renal ischemia injury on brain in diabetic and non-diabetic rats: Role of angiotensin II type 2 receptor and angiotensin-converting enzyme 2

Clinically, patients with diabetes mellitus (DM) are more susceptible to ischemic renal injury (IRI) than non-diabetic (ND) patients. Besides, IRI predisposes distant organ dysfunctions including, neurological dysfunction, in which the major contributor remains renin-angiotensin system (RAS). Interestingly, the role of depressor arm of RAS on IRI-associated neurological sequalae remains unclear. Hence, this study aimed to delineate the role of angiotensin II type 2 receptor (AT2R) and angiotensin-converting enzyme 2 (ACE2) under the same. ND and Streptozotocin-induced DM rats with bilateral IRI were treated with AT2R agonist-Compound 21 (C21) (0.3 mg/kg/day, i.p.) or ACE2 activator-Diminazene Aceturate (Dize), (5 mg/kg/day, p.o.) either alone or as combination therapy. Effect of IRI on neurological functions were assessed by behavioural, biochemical, and histopathological analysis. Immunohistochemistry, ELISA and qRT-PCR experiments were conducted for evaluation of the molecular mechanisms. We found that in ND and DM rats, IRI causes increased hippocampal MDA and nitrite levels, augmented inflammatory cytokines (granulocyte-colony stimulating factor, glial fibrillary acidic protein), altered protein levels of Ang II, Ang-(1-7) and mRNA expressions of At1r, At2r and Masr. Treatment with C21 and Dize effectively normalised above-mentioned pathological alterations. Moreover, the protective effect of C21 and Dize combination therapy was better than respective monotherapies, and more likely, exerted via augmentation of protein and mRNA levels of depressor arm components. Thus, AT2R agonist and ACE2 activator therapy prevents the development of IRI-associated neurological dysfunction by attenuating oxidative stress and inflammation, upregulating depressor arm of RAS in brain under ND and DM conditions.

Effects of Ischemia-Reperfusion on Tubular Cell Membrane Transporters and Consequences in Kidney Transplantation

Ischemia-reperfusion (IR)-induced acute kidney injury (IRI) is an inevitable event in kidney transplantation. It is a complex pathophysiological process associated with numerous structural and metabolic changes that have a profound influence on the early and the late function of the transplanted kidney. Proximal tubular cells are particularly sensitive to IRI. These cells are involved in renal and whole-body homeostasis, detoxification processes and drugs elimination by a transporter-dependent, transcellular transport system involving Solute Carriers (SLCs) and ATP Binding Cassettes (ABCs) transporters. Numerous studies conducted mainly in animal models suggested that IRI causes decreased expression and activity of some major tubular transporters. This could favor uremic toxins accumulation and renal metabolic alterations or impact the pharmacokinetic/toxicity of drugs used in transplantation. It is of particular importance to understand the underlying mechanisms and effects of IR on tubular transporters in order to improve the mechanistic understanding of IRI pathophysiology, identify biomarkers of graft function or promote the design and development of novel and effective therapies. Modulation of transporters’ activity could thus be a new therapeutic opportunity to attenuate kidney injury during IR.

Quality of Care for Acute Kidney Disease: Current Knowledge Gaps and Future Directions

Acute kidney injury (AKI) and acute kidney disease (AKD) are common complications in hospitalized patients and are associated with adverse outcomes. Although consensus guidelines have improved the care of patients with AKI and AKD, guidance regarding quality metrics in the care of patients after an episode of AKI or AKD is limited. For example, few patients receive follow-up laboratory testing of kidney function or post-AKI or AKD care through nephrology or other providers. Recently, the Acute Disease Quality Initiative developed a consensus statement regarding quality improvement goals for patients with AKI or AKD specifically highlighting efforts regarding quality and safety of care after hospital discharge after an episode of AKI or AKD. The goal is to use these measures to identify opportunities for improvement that will positively affect outcomes. We recommend that health care systems quantitate the proportion of patients who need and actually receive follow-up care after the index AKI or AKD hospitalization. The intensity and appropriateness of follow-up care should depend on patient characteristics, severity, duration, and course of AKI of AKD, and should evolve as evidence-based guidelines emerge. Quality indicators for discharged patients with dialysis requiring AKI or AKD should be distinct from end-stage renal disease measures. Besides, there should be specific quality indicators for those still requiring dialysis in the outpatient setting after AKI or AKD. Given the limited preexisting data guiding the care of patients after an episode of AKI or AKD, there is ample opportunity to establish quality measures and potentially improve patient care and outcomes. This review will provide specific evidence-based and expert opinion–based guidance for the care of patients with AKI or AKD after hospital discharge.

Amelioration of testicular damages in renal ischemia/reperfusion by berberine: An experimental study

Background

Ischemic acute kidney injury is associated with an inflammatory reaction.

Objective

In the current study, berberine was assessed for its effect on the functional disorders and histological damages of testis induced by renal ischemia/reperfusion (I/R).

Materials and Methods

Twenty-eight adult male Wistar rats (260-300 gr) were equally divided into four groups (n = 7/each): sham and I/R groups which received distilled water as well as berberine (BBR) and BBR + I/R groups which received berberine (15 mg/kg/day) orally seven days before the surgery. In both groups of sham and BBR, renal arteries were not clamped. Renal I/R was induced by occluding right and left renal artery for 45 min followed by a 24 hr reperfusion period. Blood samples were taken for determining the plasma levels of creatinine, urea nitrogen, FSH (follicle stimulating hormone), LH (luteinizing hormone), and testosterone. Then the rats were killed under deep anesthesia and the left testis was immediately isolated and preserved.

Results

The renal I/R injury led to testicular histological damages accompanied with increased plasma levels of creatinine, urea nitrogen, LH, and FSH, as well decrease of plasma testosterone concentration at the end of 24 hr reperfusion (All p < 0.001, except for FSH p < 0.01). Berberine diminished histological damage to the testis and attenuated the increase in plasma creatinine, urea nitrogen, LH, FSH, and decrease in plasma testosterone concentration in the BBR + I/R group (All p < 0.001).

Conclusion

These results suggest that ischemic acute renal failure induces functional disorders and tissue damages in testis of rat, which was improved through the administration of berberine.

The Incidence of Chronic Kidney Disease Three Years after Non-Severe Acute Kidney Injury in Critically Ill Patients: A Single-Center Cohort Study

The risk of chronic kidney disease (CKD) following severe acute kidney injury (AKI) in critically ill patients is well documented, but not after less severe AKI. The main objective of this study was to evaluate the long-term incidence of CKD after non-severe AKI in critically ill patients. This prospective single-center observational three-years follow-up study was conducted in the medical intensive care unit in Bordeaux's hospital (France). From 2013 to 2015, all patients with severe (kidney disease improving global outcomes (KDIGO) stage 3) and non-severe AKI (KDIGO stages 1, 2) were enrolled. Patients with prior eGFR < 90 mL/min/1.73 m² were excluded. Primary outcome was the three-year incidence of CKD stages 3 to 5 in the non-severe AKI group. We enrolled 232 patients. Non-severe AKI was observed in 112 and severe AKI in 120. In the non-severe AKI group, 71 (63%) were male, age was 62 ± 16 years. The reason for admission was sepsis for 56/112 (50%). Sixty-two (55%) patients died and nine (8%) were lost to follow-up. At the end of the follow-up the incidence of CKD was 22% (9/41); Confidence Interval (CI) _95% (9.3-33.60)% in the non-severe AKI group, tending to be significantly lower than in the severe AKI group (44% (14/30); CI _95% (28.8-64.5)%; p = 0.052). The development of CKD three years after non-severe AKI, despite it being lower than after severe AKI, appears to be a frequent event highlighting the need for prolonged follow-up.

Organ crosstalk: the potent roles of inflammation and fibrotic changes in the course of organ interactions

BACKGROUND

Organ crosstalk can be defined as the complex and mutual biological communication between distant organs mediated by signaling factors. Normally, crosstalk helps to coordinate and maintain homeostasis, but sudden or chronic dysfunction in any organ causes dysregulation in another organ. Many signal molecules, including cytokines and growth factors, are involved in the metabolic dysregulation, and excessive or inappropriate release of these molecules leads to organ dysfunction or disease (e.g., obesity, type 2 diabetes).

AIM AND METHOD

The aim of this review is to reveal the impact of organ crosstalk on the pathogenesis of diseases associated with organ interactions and the role of inflammatory and fibrotic changes in the organ dysfunction. After searching in MEDLINE, PubMed and Google Scholar databases using 'organ crosstalk' as a keyword, studies related to organ crosstalk and organ interaction were compiled and examined.

CONCLUSION

The organ crosstalk and the functional integration of organ systems are exceedingly complex processes. Organ crosstalk contributes to metabolic homeostasis and affects the inflammatory response, related pathways and fibrotic changes. As in the case of interactions between adipose tissue and intestine, stimulation of inflammatory mechanisms plays an active role in the development of diseases including insulin resistance, obesity, type 2 diabetes and hepatic steatosis. The increased level of knowledge about the 'crosstalk' between any organ and distant organs will facilitate the early diagnosis of the disease as well as the management of the treatment practices in the short- and long-term organ dysfunction.

Acute Kidney Injury following Cardiac Surgery: A Clinical Model

BACKGROUND

Scientists use preclinical models of acute kidney injury (AKI) to decipher mechanisms and develop therapy, but translation of therapies to patients remains poor. Models that better resemble patients, including those within clinical care, should be considered.

SUMMARY

Mice provide many advantages to the study of human disease including an ability to dictate precise experimental conditions. To best isolate and measure phenomena, scientists reduce experimental variability - identical animals, environmental conditions, experimental exposures, and outcome assessments. This technique reduces effect size variability and increases power but dissociates these model organisms from the clinical patients they intend to represent, potentially accounting for the poor translation of findings into patient care. Clinical research, conversely, is often plagued by heterogeneous patients, heterogenous environmental factors, and heterogenous renal insults. A compromise between these 2 extremes - a model of AKI that is more similar to human disease but still provides opportunities for rigorous investigation - should be utilized. Cardiac surgery provides a clinical model for the study of AKI due to mechanism overlap it shares with other clinical conditions (improved generalizability) and characteristics that provide distinct opportunities for research. The high rate of AKI following cardiac surgery and the relative homogeneity (decreased variability) of cardiac surgery subjects, their environment, and renal insults increase power and the opportunity to make discoveries and advance care. Moreover, the elective nature of cardiac surgery provides opportunities to perform detailed baseline assessments and pretreat select patients. Key Messages: Models that better reflect clinical AKI are needed to decipher mechanisms and develop effective treatments. Cardiac surgery is an important clinical model form for the study of AKI.

Vagus nerve stimulation protects against acute liver injury induced by renal ischemia reperfusion via antioxidant stress and anti-inflammation

OBJECTIVE

Renal ischemia reperfusion (I/R) is not an isolated event; however, it results in remote organ dysfunction. Vagus nerve stimulation (VNS) has shown protective effects against renal I/R injury via an anti-inflammatory mechanism. This study aimed to investigate whether VNS could attenuate liver injury induced by renal I/R and identify the underlying mechanisms.

METHODS

Eighteen healthy male Sprague-Dawley rats (200-250 g) were equally divided into three groups: sham group (sham surgery without I/R or VNS), I/R group (renal I/R) and VNS group (renal I/R plus VNS). The I/R model was established by excising the right kidney and then clamping the left renal pedicle with an occlusive nontraumatic microaneurysm clamp for 45 min followed by a 6-h reperfusion. The rats in the VNS group received spontaneous left cervical VNS with renal ischemia and reperfusion. At the end of the experiment, blood and liver tissues were collected to detect liver function, oxidative stress and inflammatory parameters. Additionally, TUNEL staining, real-time PCR, western blotting and hematoxylin and eosin staining of liver tissues were performed to assess liver injury and the underlying mechanisms.

RESULTS

Kidney and liver function was severely damaged in the I/R group compared to the sham group. However, VNS significantly protected kidney and liver function. Rats treated with VNS revealed decreases in oxidative enzymes, apoptosis and levels of tumor necrosis factor alpha (TNF-α) and interleukin 6 (IL-6) in serum and liver compared with rats in the I/R group. Rats in the VNS group also showed increased antioxidant stress responses compared to rats in the I/R group.

CONCLUSION

VNS exerts protective effects against liver injury from renal I/R via inhibiting oxidative stress and apoptosis, downregulating inflammatory cytokines and enhancing antioxidative capability in the liver, and may become a promising adjuvant therapeutic strategy for treating liver injury induced by acute renal injury.

Tetramethylpyrazine Prevents Contrast-Induced Nephropathy via Modulating Tubular Cell Mitophagy and Suppressing Mitochondrial Fragmentation, CCL2/CCR2-Mediated Inflammation, and Intestinal Injury

Contrast-induced nephropathy (CIN) is a leading cause of hospital-acquired acute kidney injury (AKI), but detailed pathogenesis and effectual remedy remain elusive. Here, we tested the hypothesis that contrast media (CM) impaired mitochondrial quality control (MQC) in tubules, including mitochondrial fragmentation and mitophagy, induced systemic inflammation, and intestinal injury. Since we previously demonstrated that the natural antioxidant 2,3,5,6-tetramethylpyrazine (TMP) can be a protectant against CIN, we moreover investigated the involved renoprotective mechanisms of TMP. In a well-established CIN rat model, renal functions, urinary AKI biomarkers, and renal reactive oxygen species (ROS) production were measured. Mitochondrial damage and mitophagy were detected by transmission electron microscopy (TEM) and western blot. The abundance of Drp1 and Mfn2 by western blot and immunohistochemistry (IHC) was used to evaluate mitochondrial fragmentation. TUNEL staining, TEM, and the abundance of cleaved-caspase 3 and procaspase 9 were used to assay apoptosis. We demonstrated that increased mitophagy, mitochondrial fragmentation, ROS generation, autophagy, and apoptosis occurred in renal tubular cells. These phenomena were accompanied by renal dysfunction and an increased excretion of urinary AKI biomarkers. Meanwhile, CM exposure resulted in concurrent small intestinal injury and villous capillary endothelial apoptosis. The abundance of the inflammatory cytokines CCL2 and CCR2 markedly increased in the renal tubules of CIN rats, accompanied by increased concentrations of IL-6 and TNF-α in the kidneys and the serum. Interestingly, TMP efficiently prevented CM-induced kidney injury in vivo by reversing these pathological processes. Mechanistically, TMP inhibited the CM-induced activation of the CCL2/CCR2 pathway, ameliorated renal oxidative stress and aberrant mitochondrial dynamics, and modulated mitophagy in tubular cells. In summary, this study demonstrated novel pathological mechanisms of CIN, that is, impairing MQC, inducing CCL2/CCR2-mediated inflammation and small intestinal injury, and provided novel renoprotective mechanisms of TMP; thus, TMP may be a promising therapeutic agent for CIN.

Diastolic dysfunction and acute kidney injury in elderly patients with femoral neck fracture

Background

Femoral neck fracture is common in the elderly population. Acute kidney injury (AKI) is an important risk factor for mortality in patients who have had such fracture. We evaluated the incidence of AKI in patients who had femoral neck fracture and identified risk factors for AKI and mortality.

Methods

This was an observational cohort study including 285 patients who were ≥ 65 years of age and who underwent femoral neck fracture surgery between 2013 and 2017.

Results

The mean age was 78.63 ± 6.75 years. A total of 67 (23.5%) patients developed AKI during the hospital stay: 57 (85.1%), 5 (7.5%), and 5 (7.5%) patients were classified as having stage 1, 2, and 3 AKI, respectively. Patients with AKI had a lower baseline estimated glomerular filtration rate and higher left atrial dimension, left ventricular mass index, pulmonary artery pressure, and the ratio of early mitral inflow velocity to early diastolic mitral annulus velocity (E/e’) and were more likely to have diabetes or hypertension (HTN) (P < 0.05). The presence of HTN (odds ratio [OR], 4.570; 95% confidence interval [CI], 1.632–12.797) higher E/e’ (OR, 1.105; 95% CI, 1.019–1.198), and lower hemoglobin (OR, 0.704; 95% CI, 0.528–0.938) were independently associated with a higher risk for developing AKI. Severe AKI (OR, 24.743; 95% CI, 2.822–212.401) was associated with a higher risk of mortality.

Conclusion

Elderly patients with femoral neck fracture had a high incidence of AKI. Diastolic dysfunction was associated with AKI. Severe AKI was associated with in-hospital mortality.

Role of renin-angiotensin system in acute kidney injury-chronic kidney disease transition

Acute kidney injury (AKI) can increase the risk of developing incident chronic kidney disease (CKD). The severity, frequency and duration of AKI are crucial predictors of poor renal outcome. A repair process after AKI can be adaptive and kidney recovers completely after a mild injury. However, severe injury will lead to a maladaptive repair, which frequently progresses to nephron loss, vascular rarefaction, chronic inflammation and fibrosis. Although different mechanisms underlying AKI-CKD transition have been extensively discussed, no definite intervention has been proved effective to block or to retard the transition until recently. In CKD, renin-angiotensin system (RAS) inhibitor has been proved effective to slow down disease progression. Furthermore, RAS needs to be highlighted again in AKI-CKD transition because recent animal studies have shown the activation of intra-renal RAS after AKI, and RAS blockade can reduce the ensuing CKD and mortality. In patients with the complete renal recovery after AKI, administration of RAS inhibitor is associated with reduced risk of subsequent CKD as well. In this article, we will demonstrate the role of RAS in AKI-CKD transition comprehensively. We will then emphasize the promising effect of RAS inhibitor on CKD prevention in patients recovering from AKI based on evidence from the bench to clinical research. All of these discussions will contribute to the establishment of reliable monitoring and therapeutic strategies for patients with functional recovery from AKI who can be most easily ignored.

Fluid Overload and Kidney Injury Score as a Predictor for Ventilator-Associated Events

Objective: The Pediatric and Neonatal Working group developed new ventilator associated events (VAE) definitions for children and neonates. VAE includes ventilator-associated condition (VAC), infection-related ventilator-associated complication (IVAC), and ventilator-associated pneumonia (VAP). Acute kidney injury (AKI) and fluid overload (FO) have been associated with worse clinical outcomes of ventilated children. Fluid Overload and Kidney Injury Score (FOKIS) is an automatically calculated score that combines AKI and FO in one numeric quantifiable metric. This study analyzed the association between FOKIS and VAE. Design: Retrospective matched case control study. Setting: A freestanding children's hospital. Patients: A total of 168 who were ventilated > 2 days. Interventions: None. Measurements and Main Results: We identified 42 VAC cases (18 IVAC and 24 non-infection-related VAC cases). Controls were matched to cases for age, immunocompromised status and ventilator days prior to VAC. VAC cases had longer ICU days, median (IQR), 28.5 (15, 47) vs. controls 11 (6, 16), p < 0.001; longer ventilation days, 19.5 (13, 32) vs. 9 (4,13), p < 0.001; and higher hospital mortality, 45.2 vs. 18%, p < 0.001. VACs had a higher incidence of AKI, 85.7 vs. 47.3%, p < 0.001; higher peak daily FO% within 3 days preceding VAC, mean (SD), 8.1(7.8) vs. 4.1 (3.4), p < 0.005; and higher peak FOKIS, 6.4(3.8) vs. 3.7(2.8), (p < 0.001). Multivariate regression model adjusted for severity of illness identified peak FOKIS (odds ratio [OR] 1.29, 95%CI: 1.14-1.48, p < 0.001) and peak inspiratory pressure (OR 1.08, 95%CI: 1.02-1.15, p = 0.007) as risk factors for VAC. Conclusions: The FOKIS and its clinical variables were associated risk factors for ventilator-associated events. Further studies will determine the utility of FOKIS as a predictor for VAEs.

Diagnostic Utility of Serum Neutrophil Gelatinase-Associated Lipocalin in Polytraumatized Patients Suffering Acute Kidney Injury: A Prospective Study

Introduction

The incidence of acute kidney injury (AKI) considerably increases the mortality rate in polytrauma victims. Undoubtedly, early identification of patients at risk is crucial for timely implementation of preventive strategies in order to improve their prognosis. Therefore, we aimed to investigate if serum neutrophil gelatinase-associated lipocalin (sNGAL) may serve as a diagnostic biomarker of early AKI in polytrauma victims, especially considering patients needing renal replacement theory (RRT).

Material and Methods

Forty consecutive polytrauma victims (ISS ≥ 16, AIS_Thorax ≥ 1, age ≥ 18 years, survival time ≥ 48 hours), directly admitted to our level I trauma center within one posttraumatic hour, were enrolled in our prospective study. sNGAL-levels were assessed at admission (initial) and on day 2 after trauma. AKI was diagnosed by an increase of serum creatinine (sCr) level of at least 0.3 mg/dl within 48 hours.

Results

Out of 30 men and 10 women (mean age, 43 years; mean ISS, 29), seven patients developed AKI, four of them needing RRT. AKI was diagnosed in 86% of the affected individuals until day 2. Day2-sNGAL-levels were higher in the AKI-group, compared to the no-AKI-group (p=0.049), and in patients treated with RRT than in individuals not needing RRT (p=0.037). Noteworthy, in patients not needing RRT sNGAL-levels significantly decreased from initial to day2-measurement (p=0.040). Furthermore, at any time point during our observation period polytraumatized patients with AKI and day2-sNGAL-levels of at least 181.0 ng/mL presented with higher sCr-levels compared to polytraumatized patients without AKI and day2-sNGAL-levels lower than 181.0 ng/mL (p≤0.029).

Conclusion

In polytrauma victims suffering AKI an increase in sNGAL-level from initial to day2-assessment may signalize deterioration in kidney function and thus indicate AKI progression. Unlike initial sNGAL-levels day2-sNGAL-levels might be an appropriate tool to define AKI and to signify the need of RRT in polytraumatized patients.

Propensity-score-matched evaluation of under-recognition of acute kidney injury and short-term outcomes

Acute kidney injury (AKI) is a common disease, but diagnosis is usually delayed or missed in hospitalized patients. The aim of this study was to investigate the impact of under-recognition of AKI (beyond 3 days after AKI onset) on short-time prognosis. Of 785 patients with under-recognition of AKI and 616 patients with timely-recognition of AKI were propensity matched in a 1:1 ratio. The two groups, with a total of 482 matched patients (241:241), were comparable in baseline covariates. Under-recognition of AKI was not associated with 30-day all-cause mortality in the logistic regression model with covariate adjustment (OR = 1.01, 95% CI = 0.62–1.64, p = 0.967). Sensitivity analyses and subgroup analyses also proved the association. There were also no significant differences in causes of 30-day mortality, in-hospital mortality, recovery of renal function at discharge, length of hospital stay, length of intensive care unit stay or hospitalization costs between the two groups, although timely-recognition group had more chance of renal consult and a little more interventions for AKI. In conclusion, under-recognition of AKI may not be associated with poor short-term outcomes of adult hospitalized patients via these propensity-score-matched analyses.

Risk of Incident Non-Valvular Atrial Fibrillation after Dialysis-Requiring Acute Kidney Injury

The influence of acute kidney injury (AKI) on subsequent incident atrial fibrillation (AF) has not yet been fully addressed. This retrospective nationwide cohort study was conducted using Taiwan’s National Health Insurance Research Database from 1 January 2000 to 31 December 2010. A total of 41,463 patients without a previous AF, mitral valve disease, and hyperthyroidism who developed de novo dialysis-requiring AKI (AKI-D) during their index hospitalization were enrolled. After propensity score matching, “non-recovery group” (n = 2895), “AKI-recovery group” (n = 2895) and “non-AKI group” (control group, n = 5790) were categorized. Within a follow-up period of 6.52 ± 3.88 years (median, 6.87 years), we found that the adjusted risks for subsequent incident AF were increased in both AKI-recovery group (adjusted hazard ratio (aHR) = 1.30; 95% confidence intervals (CI), 1.07–1.58; p ≤ 0.01) and non-recovery group (aHR = 1.62; 95% CI, 1.36–1.94) compared to the non-AKI group. Furthermore, the development of AF carried elevated risks for major adverse cardiac events (aHR = 2.11; 95% CI, 1.83–2.43), ischemic stroke (aHR = 1.33; 95% CI, 1.19–1.49), and all stroke (aHR = 1.28; 95% CI, 1.15–1.43). (all p ≤ 0.001, except otherwise expressed) The authors concluded that AKI-D, even in those who withdrew from temporary dialysis, independently increases the subsequent risk of de novo AF.

Long-term consequences of acute kidney injury in the perioperative setting

PURPOSE OF REVIEW

Recent studies indicate that acute kidney injury (AKI) and chronic kidney disease (CKD) are interconnected syndromes. Although the majority of patients who suffer an episode of AKI will recover laboratory indices suggesting complete or near complete recovery of renal function, a significant portion of post-AKI survivors will develop major kidney events, including development of late-stage CKD, need for renal replacement therapies, and death.

RECENT FINDINGS

Our review highlights epidemiology of adverse post-AKI events, association of AKI with late development of nonrenal adverse outcomes, use of bedside equations that facilitate prognostication of adverse renal outcomes of AKI, and how variability in serum creatinine values in individual patients, even among those with normal baseline renal function may indicate risk for the development of CKD. Use of common laboratory parameters such as serum creatinine and albumin, along with certain clinical and demographic markers, individualize patients at high risk of complications and in need of close postdischarge follow-up. Evidence that 'organ crosstalk' following a major AKI episode may increase the risk of heart failure, stroke, and hypertension, places its survivors in a special patient category deserving active efforts to minimize risk for cardiovascular events.

SUMMARY

AKI is a major cause for acute in-hospital mortality and development of both late-stage CKD and cardiovascular events. Perioperative care to prevent AKI must challenge the notion that a single normal point of contact serum creatinine value substantially reduces the likelihood of its occurrence.

Outcome Prediction of Acute Kidney Injury Biomarkers at Initiation of Dialysis in Critical Units

: The ideal circumstances for whether and when to start RRT remain unclear. The outcome predictive ability of acute kidney injury (AKI) biomarkers measuring at dialysis initializing need more validation. This prospective, multi-center observational cohort study enrolled 257 patients with AKI undergoing renal replacement therapy (RRT) shortly after admission. At the start of RRT, blood and urine samples were collected for relevant biomarker measurement. RRT dependence and all-cause mortality were recorded up to 90 days after discharge. Areas under the receiver operator characteristic (AUROC) curves and a multivariate generalized additive model were applied to predict outcomes. One hundred and thirty-five (52.5%) patients died within 90 days of hospital discharge. Plasma c-terminal FGF-23 (cFGF-23) had the best discriminative ability (AUROC, 0.687) as compared with intact FGF-23 (iFGF-23) (AUROC, 0.504), creatinine-adjusted urine neutrophil gelatinase-associated lipocalin (AUROC, 0.599), and adjusted urine cFGF-23 (AUROC, 0.653) regardless whether patients were alive or not on day 90. Plasma cFGF-23 levels above 2050 RU/mL were independently associated with higher 90-day mortality (HR 1.76, p = 0.020). Higher cFGF-23 levels predicted less weaning from dialysis in survivors (HR, 0.62, p = 0.032), taking mortality as a competing risk. Adding cFGF-23 measurement to the AKI risk predicting score significantly improved risk stratification and 90-day mortality prediction (total net reclassification improvement = 0.148; p = 0.002). In patients with AKI who required RRT, increased plasma cFGF-23 levels correlated with higher 90-day overall mortality after discharge and predicted worse kidney recovery in survivors. When coupled to the AKI risk predicting score, cFGF-23 significantly improved mortality risk prediction. This observation adds evidence that cFGF-23 could be used as an optimal timing biomarker to initiate RRT.

Risk of Preeclampsia and Pregnancy Complications in Women With a History of Acute Kidney Injury

An episode of clinically recovered acute kidney injury (r-AKI) has been identified as a risk factor for future hypertension and cardiovascular disease. Our objective was to assess whether r-AKI was associated with future preeclampsia and other adverse pregnancy outcomes and to identify whether severity of AKI or time interval between AKI and pregnancy was associated with pregnancy complications. We conducted a retrospective cohort study of women who delivered infants between 1998 and 2016 at Massachusetts General Hospital. AKI was defined using the 2012 Kidney Disease Improving Global Outcomes laboratory criteria with subsequent clinical recovery (estimate glomerular filtration rate, >90 mL/min per 1.73 m² before conception). AKI was further classified by severity (Kidney Disease Improving Global Outcomes stages 1-3) and time interval between AKI episode and the start of pregnancy. Women with r-AKI had an increased rate of preeclampsia compared with women without previous r-AKI (22% versus 9%; P<0.001). Infants of women with r-AKI were born earlier (gestational age, 38.2±3.0 versus 39.0±2.2 weeks; P<0.001) and were more likely to be small for gestational age (9% versus 5%; P=0.002). Increasing severity of r-AKI was associated with increased risk of preeclampsia for stages 2 and 3 AKI (adjusted odds ratio, 3.5; 95% confidence interval, 2.1-5.7 and adjusted odds ratio, 6.5; 95% confidence interval, 3.5-12.0, respectively), but not for stage 1 (adjusted odds ratio, 1.7; 95% confidence interval, 0.9-3.2). A history of AKI before pregnancy, despite apparent full recovery, was associated with increased risk of pregnancy complications. Severity and timing of the AKI episode modified the risk.

Renal recovery

Recovery patterns after acute kidney injury (AKI) have increasingly become the focus of research, because currently available preventive measures and specific therapeutic intervention are limited. Moreover, changes in renal functional reserve are recognized as a "hidden" indicator of kidney susceptibility to either acute kidney injury or chronic kidney disease. Understanding these phenomena and their association with outcome may enable the initiation of strategies that facilitate fast and sustained recovery during the time course of AKI and limit AKI progression towards chronic kidney disease. Different interventions may be required during various phases of AKI continuum. Early recognition and prevention of second hit by kidney stress, treatment of cause and prevention of aggravation in the early phase of AKI and facilitation of recovery in the phase of acute kidney disease may together represent the key aspects of modern AKI management.

Optimal timing of renal replacement therapy initiation in acute kidney injury: the elephant felt by the blindmen?

Renal replacement therapy (RRT) is a key component in the management of severe acute kidney injury (AKI) in critically ill patients. Many cohort studies, meta-analyses, and two recent large randomized prospective trials which evaluated the relationship between the timing of RRT initiation and patient outcome remain inconclusive due to substantial differences in study design, patient population, AKI definition, and RRT indication. A cause-specific diagnosis of AKI based on current staging criteria plus a sensitive biomarker (panel) that allows creating a homogeneous study population is definitely needed to assess the impact of early versus late initiation of RRT on patient outcome.

Novel insights into acute kidney injury-chronic kidney disease continuum and the role of renin-angiotensin system

Acute kidney injury (AKI) is an independent risk factor for chronic kidney disease (CKD). If injury is mild, a repair process can be adaptive and lead to complete renal recovery. However, severe injury will be accompanied by a maladaptive repair which usually leads to nephron loss, fibrosis, vascular rarefaction, and chronic inflammation. Although various mechanisms underlying AKI-CKD transition have been explored, no intervention has been proved effective to block the transition until very recently. A lack of consensus for monitoring renal function and defining renal recovery after AKI should be the reasons for the slow advance in the discovery of a timely pharmacologic treatment to block AKI-CKD transition. Recently, animal studies have shown the activation of renin-angiotensin system (RAS) after AKI. In patients with complete renal recovery after AKI defined as the decrease of serum creatinine level to within 0.3 mg/dL above the baseline, administration of RAS inhibitor can prevent the ensuing CKD. In this review, we will discuss the renal recovery after AKI and the mechanisms underlying AKI-CKD transition. We will then highlight the promising effect of RAS inhibitor on CKD prevention in patients with complete renal recovery from AKI based on the recent clinical evidence.

Recommendations of the Working Groups from the Spanish Society of Intensive and Critical Care Medicine and Coronary Units (SEMICYUC) for the management of adult critically ill patients

The standardization of the Intensive Care Medicine may improve the management of the adult critically ill patient. However, these strategies have not been widely applied in the Intensive Care Units (ICUs). The aim is to elaborate the recommendations for the standardization of the treatment of critical patients. A panel of experts from the thirteen working groups (WG) of the Spanish Society of Intensive and Critical Care Medicine and Coronary Units (SEMICYUC) was selected and nominated by virtue of clinical expertise and/or scientific experience to carry out the recommendations. Available scientific literature in the management of adult critically ill patients from 2002 to 2016 was extracted. The clinical evidence was discussed and summarised by the experts in the course of a consensus finding of every WG and finally approved by the WGs after an extensive internal review process that was carried out between December 2015 and December 2016. A total of 65 recommendations were developed, of which 5 corresponded to each of the 13 WGs. These recommendations are based on the opinion of experts and scientific knowledge, and are intended as a guide for the intensivists in the management of critical patients.

Outcomes of acute kidney injury in a department of internal medicine in ABIDJAN (cote D'IVOIRE)

AIM

To investigate the prognostic factors of acute kidney injury (AKI) in our daily practice.

METHODS

We analyzed the cohort of patients hospitalized for AKI in the period from January 2010 to December 2015 in the Department of Internal Medicine, University Hospital of Treichville. Kaplan-Meier curves were built for survival analysis. Cox regression analysis was used to identify independent predictors of mortality.

RESULTS

We collected 414 cases of AKI during the study period. The mean age was 48.3 ± 16.8 years. We observed a male predominance with a sex ratio (236/178) of 1.32. In multivariate analysis, the predictive factors of death were age ≥ 65 years (HR = 2.13; 95% CI = 1.28-3.55; P = 0.004), AKI stage 3 (HR = 1.69; 95%CI = 1.13-2.50; P = 0.009), haemoglobin <8 g/dL (HR = 2.91; 95% CI = 1.79-4.72; P = 0.0001), infection (HR = 1.85; 95% CI = 1.21-2.83; P = 0.004) and drug-induced AKI (HR = 3.23; 95% CI = 1.65-6.29; P = 0.001). Factors associated with incomplete recovery or non-recovery of renal function beyond 3 months were age ≥ 65 years (OR = 4.76; 95% CI = 1.85-12.50;P = 0.001), hypertension (OR = 2.17; 95% CI = 1.07-4.34; P = 0.03), haemoglobin <8 g/dL (OR = 6.66; 95% CI = 2.94-8.28; P < 0.001), AKI stage 3 (OR = 9.09; 95% CI = 4.54-16.66; P < 0.001) malignant hypertension (OR = 5; 95% CI = 1.67-7.27; P = 0.005) and cancer (OR = 4.69; 95% CI = 2.22-6.63; P = 0.001).

CONCLUSION

The aetiologies are dominated by infections. The fatality rate is high and its risk factors are advanced age, low haemoglobin level, severe AKI, infection and drug intake. Prevention is essential.

[Comparative study of community acute kidney injury in HIV infected versus non-infected persons: Experience of an internal medicine department in Abidjan (Côte d'Ivoire)]

BACKGROUND

Acute kidney injury (AKI) is commonly associated with HIV infection.

OBJECTIVES

To describe the profile of AKI in HIV infected versus non-infected persons.

PATIENTS AND METHODS

This is a prospective study that was carried out during the study period from January 2010 to December 2015 in the department of nephrology-internal medicine D of Treichville University Hospital (Côte d'Ivoire).

RESULTS

The prevalence of HIV infection was 35.2% in the population of AKI. The average age of patients was 42±18 years in the HIV positive group against 51±18 years in the HIV negative group (P=0.0001). Etiologies were infections in 65.1% in the HIV positive group against 38.8% in the HIV negative group (P=0.0001) and water loss in 24.7% in the HIV positive group against 7.8% in the HIV negative group (P=0.0001). Factors such as the AIDS stage (P=0.002), severe sepsis (P=0.002) and acute pyelonephritis (P=0.001) were associated with mortality in HIV positive patients against severe anemia (P=0.0001) and severe sepsis (P=0.0001) in the HIV-negative group.

CONCLUSION

HIV positive patients are younger with a female predominance. The mortality rate is identical in both groups.

Acute kidney disease and renal recovery: consensus report of the Acute Disease Quality Initiative (ADQI) 16 Workgroup

Consensus definitions have been reached for both acute kidney injury (AKI) and chronic kidney disease (CKD) and these definitions are now routinely used in research and clinical practice. The KDIGO guideline defines AKI as an abrupt decrease in kidney function occurring over 7 days or less, whereas CKD is defined by the persistence of kidney disease for a period of >90 days. AKI and CKD are increasingly recognized as related entities and in some instances probably represent a continuum of the disease process. For patients in whom pathophysiologic processes are ongoing, the term acute kidney disease (AKD) has been proposed to define the course of disease after AKI; however, definitions of AKD and strategies for the management of patients with AKD are not currently available. In this consensus statement, the Acute Disease Quality Initiative (ADQI) proposes definitions, staging criteria for AKD, and strategies for the management of affected patients. We also make recommendations for areas of future research, which aim to improve understanding of the underlying processes and improve outcomes for patients with AKD.

Hypotension and hypovolemia during hemodialysis: is the usual suspect innocent?

Hypotension during intermittent hemodialysis is common, and has been attributed to acute volume shifts, shifts in osmolarity, electrolyte imbalance, temperature changes, altered vasoregulation, and sheer hypovolemia. Although hypovolemia may intuitively seem a likely cause for hypotension in intensive care patients, its role in the pathogenesis of intradialytic hypotension may be overestimated.

Acute Kidney Injury: Definition, Pathophysiology and Clinical Phenotypes

Acute kidney injury (AKI) is a clinical syndrome that complicates the course and worsens the outcome in a significant number of hospitalised patients. Recent advances in clinical and basic research will help with a more accurate definition of this syndrome and in the elucidation of its pathogenesis. With this knowledge we will be able to conduct more accurate epidemiologic studies in an effort to gain a better understanding of the impact of this syndrome. AKI is a syndrome that rarely has a sole and distinct pathophysiology. Recent evidence, in both basic science and clinical research, is beginning to change our view for AKI from a single organ failure syndrome to a syndrome where the kidney plays an active role in the progress of multi-organ dysfunction. Accurate and prompt recognition of AKI and better understanding of the pathophysiologic mechanisms underlying the various clinical phenotypes are of great importance to research for effective therapeutic interventions. In this review we provide the most recent updates in the definition, epidemiology and pathophysiology of AKI.