Hepatorenal Syndrome in Cirrhosis.

Hepatorenal syndrome (HRS) is a form of kidney dysfunction that characteristically occurs in liver cirrhosis. It is characterized by a marked impairment of kidney function in response to circulatory and hemodynamic alterations that occur in advanced stages of liver cirrhosis, aggravated by systemic inflammation and bacterial translocation. The classical definitions of the types of HRS have been recently revisited and 2 forms of HRS have been redefined: the acute form, referred to as acute kidney injury (HRS-AKI), and the chronic form, referred to as chronic kidney disease. HRS-AKI is one of the most severe forms of AKI in patients with cirrhosis and it consists of an abrupt impairment of kidney function, frequently triggered by an infection, appearing in the setting of advanced decompensated cirrhosis. Differential diagnosis with other causes of AKI is crucial because HRS-AKI requires a specific treatment. Differential diagnosis with AKI-acute tubular necrosis may be challenging and kidney biomarkers may be useful in this setting. Treatment of HRS-AKI is based on the administration of vasoconstrictor drugs in combination with volume expansion with albumin. Prognosis of HRS-AKI is poor, and the ideal definitive treatment consists of liver transplantation or simultaneous liver-kidney transplantation. HRS-AKI has a big impact on patients' quality of life. Management of HRS-AKI remains challenging in specific situations such as alcohol-associated hepatitis or metabolic-associated steatotic liver disease cirrhosis. Developing preventive measures for HRS-AKI, improving its early identification, discovering new biomarkers for differential diagnosis, and improving the response to therapy are some of the unmet needs in the field of HRS-AKI.

ISL1-overexpressing BMSCs attenuate renal ischemia-reperfusion injury by suppressing apoptosis and oxidative stress through the paracrine action.

Ischemia-reperfusion injury (IRI) is a major event in renal transplantation, leading to adverse outcomes. Bone marrow mesenchymal stem cells (BMSCs) are novel promising therapeutics for repairing kidney injuries. The therapeutic efficacy of BMSCs with ISL1 overexpression in renal IRI and its underlying mechanism need to be investigated. The unilateral renal IRI rat model was established to mimic clinical acute kidney injury. Rats were injected with PBS, BMSCs-Scrambled or BMSCs-ISL1 via the tail vein at the timepoint of reperfusion, and then sacrificed after 24 h of reperfusion. The administration of BMSCs-ISL1 significantly improved renal function, inhibited tubular cells apoptosis, inflammation, oxidative stress in rats. In vitro, HKC cells subjected to H2O2 stimulation were pretreated with the conditioned medium (CM) of BMSCs-Scrambled or BMSCs-ISL1. The pretreatment of ISL1-CM attenuated apoptosis and oxidative stress induced by H2O2 in HKC cells. Our proteomic data suggested that haptoglobin (Hp) was one of the secretory proteins in ISL1-CM. Subsequent experiments confirmed that Hp was the important paracrine factor from BMSCs-ISL1 that exerted anti-apoptotic and antioxidant functions. Mechanistically, Hp played a cytoprotective role via the inhibition of ERK signaling pathway, which could be abrogated by Ro 67-7476, the ERK phosphorylation agonist. The results suggested that paracrine action may be the main mechanism for BMSCs-ISL1 to exert protective effects. As an important anti-apoptotic and antioxidant factor in ISL1-CM, Hp may serve as a new therapeutic agent for treating IRI, providing new insights for overcoming the long-term adverse effects of stem cell therapy.

Acute Kidney Injury Receiving Dialysis and Dialysis Care after Hospital Discharge.

The number of patients with AKI receiving outpatient hemodialysis (AKI-D) is increasing. At present, on the basis of limited data, approximately one third of patients with AKI-D who receive outpatient dialysis after hospital discharge survive and regain sufficient kidney function to discontinue dialysis. Data to inform dialysis management strategies that promote kidney function recovery and processes of care among patients with AKI-D receiving outpatient dialysis are lacking. In this article, we detail current trends in the incidence, risk factors, clinical outcomes, proposed management, and health policy landscape for patients with AKI-D receiving outpatient dialysis and identify areas for further research.

Blood Pressure and Oxygen Targets on Kidney Injury After Cardiac Arrest.

BACKGROUND: Acute kidney injury (AKI) represents a common and serious complication to out-of-hospital cardiac arrest. The importance of post-resuscitation care targets for blood pressure and oxygenation for the development of AKI is unknown. METHODS: This is a substudy of a randomized 2-by-2 factorial trial, in which 789 comatose adult patients who had out-of-hospital cardiac arrest with presumed cardiac cause and sustained return of spontaneous circulation were randomly assigned to a target mean arterial blood pressure of either 63 or 77 mm Hg. Patients were simultaneously randomly assigned to either a restrictive oxygen target of a partial pressure of arterial oxygen (Pao2) of 9 to 10 kPa or a liberal oxygenation target of a Pao2 of 13 to 14 kPa. The primary outcome for this study was AKI according to KDIGO (Kidney Disease: Improving Global Outcomes) classification in patients surviving at least 48 hours (N=759). Adjusted logistic regression was performed for patients allocated to high blood pressure and liberal oxygen target as reference. RESULTS: The main population characteristics at admission were: age, 64 (54-73) years; 80% male; 90% shockable rhythm; and time to return of spontaneous circulation, 18 (12-26) minutes. Patients allocated to a low blood pressure and liberal oxygen target had an increased risk of developing AKI compared with patients with high blood pressure and liberal oxygen target (84/193 [44%] versus 56/187 [30%]; adjusted odds ratio, 1.87 [95% CI, 1.21-2.89]). Multinomial logistic regression revealed that the increased risk of AKI was only related to mild-stage AKI (KDIGO stage 1). There was no difference in risk of AKI in the other groups. Plasma creatinine remained high during hospitalization in the low blood pressure and liberal oxygen target group but did not differ between groups at 6- and 12-month follow-up. CONCLUSIONS: In comatose patients who had been resuscitated after out-of-hospital cardiac arrest, patients allocated to a combination of a low mean arterial blood pressure and a liberal oxygen target had a significantly increased risk of mild-stage AKI. No difference was found in terms of more severe AKI stages or other kidney-related adverse outcomes, and creatinine had normalized at 1 year after discharge. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03141099.

Impaired hemodynamic renal reserve response following recovery from established acute kidney injury and improvement by hydrodynamic isotonic fluid delivery.

Renal reserve capacity may be compromised following recovery from acute kidney injury (AKI) and could be used to identify impaired renal function in the face of restored glomerular filtration rate (GFR) or plasma creatinine. To investigate the loss of hemodynamic renal reserve responses following recovery in a model of AKI, rats were subjected to left unilateral renal ischemia-reperfusion (I/R) injury and contralateral nephrectomy and allowed to recover for 5 wk. Some rats were treated 24 h post-I/R by hydrodynamic isotonic fluid delivery (AKI-HIFD) of saline through the renal vein, previously shown to improve recovery and inflammation relative to control rats that received saline through the vena cava (AKI-VC). At 5 wk after surgery, plasma creatinine and GFR recovered to levels observed in uninephrectomized sham controls. Baseline renal blood flow (RBF) was not different between AKI or sham groups, but infusion of l-arginine (7.5 mg/kg/min) significantly increased RBF in sham controls, whereas the RBF response to l-arginine was significantly reduced in AKI-VC rats relative to sham rats (22.6 ± 2.2% vs. 13.8 ± 1.8%, P < 0.05). RBF responses were partially protected in AKI-HIFD rats relative to AKI-VC rats (17.0 ± 2.2%) and were not significantly different from sham rats. Capillary rarefaction observed in AKI-VC rats was significantly protected in AKI-HIFD rats. There was also a significant increase in T helper 17 cell infiltration and interstitial fibrosis in AKI-VC rats versus sham rats, which was not present in AKI-HIFD rats. These data suggest that recovery from AKI results in impaired hemodynamic reserve and that associated CKD progression may be mitigated by HIFD in the early post-AKI period.NEW & NOTEWORTHY Despite the apparent recovery of renal filtration function following acute kidney injury (AKI) in rats, the renal hemodynamic reserve response is significantly attenuated, suggesting that clinical evaluation of this parameter may provide information on the potential development of chronic kidney disease. Treatments such as hydrodynamic isotonic fluid delivery, or other treatments in the early post-AKI period, could minimize chronic inflammation or loss of microvessels with the potential to promote a more favorable outcome on long-term function.

Development of PD in lower-income countries: a rational solution for the management of AKI and ESKD.

It is estimated that >50% of patients with end-stage kidney disease (ESKD) in low-resource countries are unable to access dialysis. When hemodialysis is available, it often has high out-of-pocket expenditure and is seldom delivered to the standard recommended by international guidelines. Hemodialysis is a high-cost intervention with significant negative effects on environmental sustainability, especially in resource-poor countries (the ones most likely to be affected by resultant climate change). This review discusses the rationale for peritoneal dialysis (PD) as a more resource and environmentally efficient treatment with the potential to improve dialysis access, especially to vulnerable populations, including women and children, in lower-resource countries. Successful initiatives such as the Saving Young Lives program have demonstrated the benefit of PD for acute kidney injury. This can then serve as a foundation for later development of PD services for end-stage kidney disease programs in these countries. Expansion of PD programs in resource-poor countries has proven to be challenging for various reasons. It is hoped that if some of these issues can be addressed, PD will be able to permit an expansion of end-stage kidney disease care in these countries.

Acute kidney injury in patients with cirrhosis: Acute Disease Quality Initiative (ADQI) and International Club of Ascites (ICA) joint multidisciplinary consensus meeting.

Patients with cirrhosis are prone to developing acute kidney injury (AKI), a complication associated with a markedly increased in-hospital morbidity and mortality, along with a risk of progression to chronic kidney disease. Whereas patients with cirrhosis are at increased risk of developing any phenotype of AKI, hepatorenal syndrome (HRS), a specific form of AKI (HRS-AKI) in patients with advanced cirrhosis and ascites, carries an especially high mortality risk. Early recognition of HRS-AKI is crucial since administration of splanchnic vasoconstrictors may reverse the AKI and serve as a bridge to liver transplantation, the only curative option. In 2023, a joint meeting of the International Club of Ascites (ICA) and the Acute Disease Quality Initiative (ADQI) was convened to develop new diagnostic criteria for HRS-AKI, to provide graded recommendations for the work-up, management and post-discharge follow-up of patients with cirrhosis and AKI, and to highlight priorities for further research.

Lower uromodulin serum levels are associated with poorer prognosis in patients with cirrhosis and hepatorenal syndrome type 2.

Hepatorenal syndrome (HRS) is associated with a dismal prognosis in patients with cirrhosis, and therapeutic options are limited. Biomarkers to identify patients with poor response to therapy are urgently needed. This study aimed to evaluate the predictive value of serum levels of uromodulin (sUMOD) in patients with cirrhosis and HRS treated with terlipressin and albumin (T/A). In total, 156 patients [81 patients with HRS treated with T/A, 42 patients with cirrhosis without kidney injury, and 33 patients with cirrhosis with prerenal acute kidney injury (AKI)] were included. sUMOD levels were analyzed by ELISA. Patients with HRS were prospectively followed for the composite endpoint of hemodialysis-/liver transplantation-free survival (HD/LTx-free survival). Of the 81 patients with HRS, 40 had HRS type 1 and 41 type 2. In the cohort of patients with HRS treated with T/A, median sUMOD level was 100 ng/mL (IQR 64; 144). sUMOD differed significantly between patients with HRS compared with patients without AKI (P = 0.001) but not between patients with HRS and prerenal AKI (P = 0.9). In multivariable analyses, sUMOD levels in the lowest quartile were independently associated with a lower rate of complete response to T/A (OR 0.042, P = 0.008) and a higher risk for reaching the composite endpoint of HD/LTX-free survival (HR 2.706, P = 0.013) in patients with HRS type 2 treated with T/A. In contrast, sUMOD was not significantly associated with these outcomes in patients with HRS type 1. sUMOD may be a valuable biomarker for identifying patients with HRS type 2 treated with T/A to predict response and prognosis.NEW & NOTEWORTHY Biomarkers identifying patients with hepatorenal syndrome (HRS) and poor response to therapy are urgently needed. In this study, lower serum uromodulin (sUMOD) levels were associated with poorer response to therapy with terlipressin and albumin and consequently with poorer prognosis in patients with HRS type 2. In patients with HRS type 1, there was no association between sUMOD and poorer prognosis.

The Road to Precision Medicine for Acute Kidney Injury.

OBJECTIVES: Acute kidney injury (AKI) is a common form of organ dysfunction in the ICU. AKI is associated with adverse short- and long-term outcomes, including high mortality rates, which have not measurably improved over the past decade. This review summarizes the available literature examining the evidence of the need for precision medicine in AKI in critical illness, highlights the current evidence for heterogeneity in the field of AKI, discusses the progress made in advancing precision in AKI, and provides a roadmap for studying precision-guided care in AKI. DATA SOURCES: Medical literature regarding topics relevant to precision medicine in AKI, including AKI definitions, epidemiology, and outcomes, novel AKI biomarkers, studies of electronic health records (EHRs), clinical trial design, and observational studies of kidney biopsies in patients with AKI. STUDY SELECTION: English language observational studies, randomized clinical trials, reviews, professional society recommendations, and guidelines on areas related to precision medicine in AKI. DATA EXTRACTION: Relevant study results, statements, and guidelines were qualitatively assessed and narratively synthesized. DATA SYNTHESIS: We synthesized relevant study results, professional society recommendations, and guidelines in this discussion. CONCLUSIONS: AKI is a syndrome that encompasses a wide range of underlying pathologies, and this heterogeneity has hindered the development of novel therapeutics for AKI. Wide-ranging efforts to improve precision in AKI have included the validation of novel biomarkers of AKI, leveraging EHRs for disease classification, and phenotyping of tubular secretory clearance. Ongoing efforts such as the Kidney Precision Medicine Project, identifying subphenotypes in AKI, and optimizing clinical trials and endpoints all have great promise in advancing precision medicine in AKI.

Controversies in terlipressin and transplantation in the United States: How do we MELD the two?

Hepatorenal syndrome-acute kidney injury (HRS-AKI) is a severe complication of cirrhosis that carries a poor prognosis. The recent Food and Drug Administration approval of terlipressin has substantial implications for managing HRS-AKI and liver allocation in the United States. Terlipressin has been available in Europe for over a decade, and several countries have adapted policy changes such as Model for End-Stage Liver Disease (MELD) score "lock" for HRS-AKI. In this article, we outline the European experience with terlipressin use and explore the question of whether terlipressin treatment for HRS-AKI should qualify for the MELD score "lock" in the United States in those who respond to therapy. Arguments for the MELD lock include protecting waitlist priority for terlipressin responders or partial responders who may miss offers due to MELD reduction in the terlipressin treatment window. Arguments against MELD lock include the fact that terlipressin may produce a durable response and improve overall survival and that equitable access to terlipressin is not guaranteed due to cost and availability. We subsequently discuss the proposed next steps for studying terlipressin implementation in the United States. A successful approach will require the involvement of all major stakeholders and the mobilization of our transplant community to spearhead research in this area.

Let's stop talking about 'citrate toxicity'.

PURPOSE OF REVIEW: Continuous renal replacement therapy (CRRT) is a vital medical intervention used in critically ill patients with acute kidney injury (AKI). One of the key components of adequate clearance with CRRT is the use of anticoagulants to prevent clotting of the extracorporeal circuit. Regional citrate anticoagulation is the most often recommended modality. The term 'citrate toxicity' is used to describe potential adverse effects of accumulation of citrate and subsequent hypocalcemia. However, citrate is itself not inherently toxic. The term and diagnosis of citrate toxicity are questioned in this review. RECENT FINDINGS: Citrate is being increasingly used for regional anticoagulation of the CRRT circuit. Citrate accumulation is infrequent and can cause hypocalcemia and metabolic alkalosis, which are potential adverse effects. Citrate itself, however, is not a toxic molecule. The term 'citrate toxicity' has been used to denote hypocalcemia and metabolic acidosis. However, citrate administration is well known to cause systemic and urinary alkalinization and under certain circumstances, metabolic alkalosis, but is not associated itself with any 'toxic' effects.We review the existing literature and debunk the perceived toxicity of citrate. We delve into the metabolism and clearance of citrate and question current data suggesting metabolic acidosis occurs as the result of citrate accumulation. SUMMARY: In conclusion, this article calls into question prevailing concerns about 'citrate toxicity'. We emphasize the need for a more nuanced understanding of its safety profile. We recommend discarding the term 'citrate toxicity' in favor of another frequently used, but more meaningful term: 'citrate accumulation'.

Dialysis initiation for patients with decompensated cirrhosis when liver transplant is unlikely.

PURPOSE OF REVIEW: The purpose of this review is to describe an approach that emphasizes shared decision-making for patients with decompensated cirrhosis and acute kidney injury when liver transplantation is either not an option, or unlikely to be an option. RECENT FINDINGS: When acute kidney injury occurs on a background of decompensated cirrhosis, outcomes are generally poor. Providers can also be faced with prognostic uncertainty. A lack of guidance from nephrology and hepatology professional societies means that providers rely on expert opinion or institutional practice patterns. SUMMARY: For patients who are unlikely to receive liver transplantation, the occurrence of acute kidney injury represents an opportunity for a goals of care conversation. In this article, we share strategies through which providers can incorporate more shared decision-making when caring for these patients. The approach involves creating prognostic consensus amongst multidisciplinary teams and then relying on skilled communicators to share the prognosis. Palliative care consultation can be useful when teams need assistance in the conversations.

Onconephrology: mitigation of renal injury in chemotherapy administration.

PURPOSE OF REVIEW: Onconephrology was first coined as a name for the intersection of cancer medicine and nephrology in the early 2010s. It was recognized then that beyond and understanding of kidney physiology, a new generation of nephrologists skilled in both molecular biology and precision medicine were needed to deal with the challenges of emerging cancer therapies. Stem cell transplants, biologic agents, adjuvants blocking basic cellular signaling pathways, immunotherapy were found to promote novel anticancer outcomes, but also to pose new risks to the kidneys. The field rapidly overlapped with emerging expertise in vascular glomerular disease, glomerular disease, and the same biologic agents now applied to auto immune systemic and kidney diseases. RECENT FINDINGS: Many categories of chemotherapeutic agents have been discovered to have adverse renal side effects. In this review, we address classic chemotherapeutic nephrotoxicity and oncologic clinical situations leading to acute kidney injury. We also review the frontiers of nephrotoxicity reported with cell cycle inhibitors, diverse classes of tyrosine kinase inhibitors, immune checkpoint inhibitors, chimeric antigen receptor T-cell therapy, anticancer vaccines, and thrombotic microangiopathies triggered by malignancy and chemotherapy. The aim will be to focus on published strategies to mitigate nephrotoxicity. SUMMARY: As onconephrology expands into its own field, it gives birth to new subdisciplines. An understanding that patient populations want the benefits of chemotherapy without the renal (and other) systemic toxicities is emerging. A need to develop a new class of molecular and genetic experts in onconephrology to mitigate nephrotoxicity from chemotherapy is apparent and urgent.

Cancer drugs and acute kidney injury: new therapies and new challenges.

PURPOSE OF REVIEW: Cancer therapies continue to evolve at a rapid pace and although novel treatments, including immunotherapies and targeted therapies have allowed for substantial improvements in cancer survival, they carry associated risks of acute kidney injury (AKI). We aim to summarize the existing literature on AKI associated with the spectrum of systemic cancer treatments, including conventional chemotherapies, newer immunotherapies, and the growing number of targeted cancer therapies, which may be associated with both AKI and 'pseudo-AKI'. RECENT FINDINGS: Conventional cytotoxic chemotherapies (e.g. cisplatin and other platinum-based agents, methotrexate, pemetrexed, ifosfamide, etc.) with well recognized nephrotoxicities (predominantly tubulointerstitial injury) remain in widespread use. Immunotherapies (e.g., immune checkpoint inhibitors and CAR-T therapies) may be associated with kidney immune-related adverse events, most often acute interstitial nephritis, and rarely, glomerular disease. Recently, multiple targeted cancer therapies have been associated with reduced renal tubular secretion of creatinine, causing elevations in serum creatinine and apparent 'pseudo-AKI'. To complicate matters further, these agents have had biopsy-proven, 'true' kidney injury attributed to them in numerous case reports. SUMMARY: Clinicians in nephrology and oncology must be aware of the various potential kidney risks with these agents and recognize those with clinically meaningful impact on both cancer and kidney outcomes.

Recent Advances in Kidney Replacement Therapy in Infants: A Review.

Kidney replacement therapy (KRT) is used to treat children and adults with acute kidney injury (AKI), fluid overload, kidney failure, inborn errors of metabolism, and severe electrolyte abnormalities. Peritoneal dialysis and extracorporeal hemodialysis/filtration can be performed for different durations (intermittent, prolonged intermittent, and continuous) through either adaptation of adult devices or use of infant-specific devices. Each of these modalities have advantages and disadvantages, and often multiple modalities are used depending on the scenario and patient-specific needs. Traditionally, these therapies have been challenging to deliver in infants due the lack of infant-specific devices, small patient size, required extracorporeal volumes, and the risk of hemodynamic stability during the initiation of KRT. In this review, we discuss challenges, recent advancements, and optimal approaches to provide KRT in hospitalized infants, including a discussion of peritoneal dialysis and extracorporeal therapies. We discuss each specific KRT modality, review newer infant-specific devices, and highlight the benefits and limitations of each modality. We also discuss the ethical implications for the care of infants who need KRT and areas for future research.

Kidney Dysfunction in the Setting of Liver Failure: Core Curriculum 2024.

Individuals with liver disease are susceptible to pathophysiological derangements that lead to kidney dysfunction. Patients with advanced cirrhosis and acute liver failure (ALF) are at risk of developing acute kidney injury (AKI). Hepatorenal syndrome type 1 (HRS-1, also called HRS-AKI) constitutes a form of AKI unique to the state of cirrhosis and portal hypertension. Although HRS-1 is a condition primarily characterized by marked renal vasoconstriction and kidney hypoperfusion, other pathogenic processes, such as acute tubular injury and renal vein congestion, can overlap and further complicate the course of HRS-1. ALF can lead to AKI through mechanisms that involve systemic inflammation, direct drug toxicity, or bile acid-induced tubulopathy. In addition, the growing prevalence of nonalcoholic steatohepatitis is changing the spectrum of chronic kidney disease in cirrhosis. In this installment of AJKD's Core Curriculum in Nephrology, we explore the underpinnings of how cirrhosis, ALF, acute cholestasis, and post-liver transplantation can be associated with various forms of acute, subacute, or chronic kidney diseases. We navigate through the recommended therapies for each condition, including supportive care, pharmacological interventions, kidney replacement therapy, and organ transplantation. Finally, key acid-base and electrolyte disorders associated with hepatobiliary disease are also summarized.

Low-Dose Continuous Kidney Replacement Therapy and Mortality in Critically Ill Patients With Acute Kidney Injury: A Retrospective Cohort Study.

RATIONALE & OBJECTIVE: Continuous kidney replacement therapy (CKRT) is preferred when available for hemodynamically unstable acute kidney injury (AKI) patients in the intensive care unit (ICU). The Kidney Disease: Improving Global Outcomes (KDIGO) guidelines recommend a delivered CKRT dose of 20-25mL/kg/h; however, in Japan the doses are typically below this recommendation due to government health insurance system restrictions. This study investigated the association between mortality and dose of CKRT. STUDY DESIGN: Single-center retrospective cohort study. SETTING & PARTICIPANTS: Critically ill patients with AKI treated with CKRT at a tertiary Japanese university hospital between January 1, 2012, and December 31, 2021. EXPOSURE: Delivered CKRT doses below or above the median. OUTCOME: 90-day mortality after CKRT initiation. ANALYTICAL APPROACH: Multivariable Cox regression analysis and Kaplan-Meier analysis. RESULTS: The study population consisted of 494 patients. The median age was 72 years, and 309 patients (62.6%) were men. Acute tubular injury was the leading cause of AKI, accounting for 81.8%. The median delivered CKRT dose was 13.2mL/kg/h. Among the study participants, 456 (92.3%) received delivered CKRT doses below 20mL/kg/h, and 204 (41.3%) died within 90 days after CKRT initiation. Multivariable Cox regression analysis revealed increased mortality in the below-median group (HR, 1.73 [95% CI, 1.19-2.51], P=0.004). Additionally, a significant, inverse, nonlinear association between 90-day mortality and delivered CKRT dose was observed using delivered CKRT dose as a continuous variable. LIMITATIONS: Single-center, retrospective, observational study. CONCLUSIONS: A lower delivered CKRT dose was independently associated with higher 90-day mortality among critically ill patients who mostly received dosing below the current KDIGO recommendations. PLAIN-LANGUAGE SUMMARY: The Kidney Disease: Improving Global Outcomes (KDIGO) guidelines recommend delivering a continuous kidney replacement therapy (CKRT) dose of 20-25mL/kg/h. However, it is not clear if it is safe to use delivered CKRT doses below this recommendation. In this study, over 90% of the patients received CKRT with a delivered dose below the KDIGO recommendation. We divided these patients into 2 groups based on the median delivered CKRT dose. Our findings show that a delivered CKRT dose below the median was associated with increased risk of death within 90 days. These findings show that a lower delivered CKRT dose was independently associated with higher 90-day mortality among critically ill patients who mostly received dosing below current KDIGO recommendations.

Processes of Care After Hospital Discharge for Survivors of Acute Kidney Injury: A Population-Based Cohort Study.

RATIONALE & OBJECTIVE: Survivors of acute kidney injury (AKI) are at high risk of adverse outcomes. Monitoring of kidney function, screening for proteinuria, use of statins and renin-angiotensin-aldosterone system (RAAS) inhibitors, and nephrology follow-up among survivors have not been fully characterized. We examined these processes of care after discharge in survivors of hospitalized AKI. STUDY DESIGN: Population-based retrospective cohort study. SETTING & PARTICIPANTS: Adults in Alberta, Canada, admitted to the hospital between 2009 and 2017, then followed from their discharge date until 2019 for a median follow-up of 2.7 years. EXPOSURE: Hospital-acquired AKI diagnostically conforming to Kidney Disease: Improving Global Outcomes (KDIGO) serum creatinine criteria for stage 2 or stage 3 disease, or the need for acute dialysis. OUTCOME: Outcomes after hospital discharge included the proportion of participants who had evaluation of kidney function, were seen by a specialist or general practitioner, and received postdischarge prescriptions for recommended medications for chronic kidney disease (CKD). ANALYTICAL APPROACH: Cumulative incidence curves to characterize the proportion of participants who received each process of care outcome within the first 90 days and subsequent 1-year follow-up period after hospital discharge. To avoid risks associated with multiple hypothesis testing, differences were not statistically compared across groups. RESULTS: The cohort (n=23,921) included 50.2% men (n=12,015) with a median age of 68.1 [IQR, 56.9-78.8] years. Within 90 days after discharge, 21.2% and 8.6% of patients with and without pre-existing CKD, respectively, were seen by a nephrologist; 60.1% of AKI survivors had at least 1 serum creatinine measured, but only 25.5% had an assessment for albuminuria within 90 days after discharge; 52.7% of AKI survivors with pre-existing CKD, and 51.6% with de novo CKD were prescribed a RAAS inhibitor within 4-15 months after discharge. LIMITATIONS: Retrospective data were collected as part of routine clinical care. CONCLUSIONS: The proportion of patients receiving optimal care after an episode of AKI in Alberta was low and may represent a target for improving long-term outcomes for this population. PLAIN-LANGUAGE SUMMARY: A study in Alberta, Canada, examined the care received by patients with acute kidney disease (AKI) during hospitalization and after discharge between 2007 and 2019. The results showed that a low proportion of patients with moderate to severe AKI were seen by a kidney specialist during hospitalization or within 90 days after discharge. Fewer than 25% of AKI patients had their kidney function monitored with both blood and urine tests within 90 days of discharge. Additionally, about half of AKI survivors with chronic kidney disease (CKD) were prescribed guideline recommended medications for CKD within 15 months after discharge. There is potential to improve health care delivery to these patients both in hospital and after hospital discharge.

Extracellular vesicles from induced pluripotent stem cell-derived mesenchymal stem cells enhance the recovery of acute kidney injury.

BACKGROUND AIMS: To investigate whether the extracellular vesicles (EVs) from mesenchymal stem cell-like cells derived from induced pluripotent stem cells (iMSC-EVs) can inhibit the progression of acute kidney injury (AKI). METHODS: The characteristics of iMSC-EVs were confirmed by immunoblotting, cryo-transmission electron microscopy, nanoparticle tracking analysis, and their localization in kidneys. Using human renal epithelial cells, the potential of iMSC-EVs to stimulate the growth and survival of HK-2 cells undergoing cisplatin-induced cell death was investigated. The anti-inflammatory effects of iMSC-EVs was examined in M1-polarized THP-1 macrophages. Subsequently, the therapeutic potential of iMSC-EVs was assessed in cisplatin-induced acute kidney injury in BALB/c mice. The anti-apoptotic and anti-inflammatory effect of iMSC-EVs was evaluated using serum biochemistry, histology, immunohistochemistry, and gene expression analysis. RESULTS: iMSC-EVs promoted the growth of renal epithelial cell (HK-2) and enhanced the survival of HK-2 undergoing cisplatin-induced cell death. In cisplatin-induced mice with AKI, iMSC-EVs alleviated AKI, as shown by reduced blood nitrogen urea/creatinine and increased body weight. Also, iMSC-EVs enhanced renal tissue integrity and the number of proliferating cell nuclear antigen-positive tubules. iMSC-EVs decreased the infiltration of immune cells, reduced the expression of inflammatory genes in M1-induced THP-1 cells and enhanced capillary density in the kidney of AKI mice. Real-time quantitative polymerase chain reaction analysis showed that the expression of inflammatory genes in the kidney of AKI mice was reduced compared with that received vehicle. Immunoblotting revealed that iMSC-EVs led to a decreased protein expression of key inflammatory genes. Also, iMSC-EVs reversed the activation of ERK1/2 signaling induced by AKI. Finally, iMSC-EVs inhibited the apoptosis of HK-2 cells induced by cisplatin as well as that of renal tissue of AKI mice. CONCLUSIONS: Our data suggest that iMSC-EVs have potential to become a novel, cell-free therapeutic for cisplatin-induced AKI.

Increased platelet to red blood cell transfusion ratio associated with acute kidney injury in children with life-threatening bleeding.

INTRODUCTION: Transfusion may increase the risk of organ failure through immunomodulatory effects. The primary objective of this study was to assess for patient or transfusion-related factors that are independently associated with the risk of acute kidney injury (AKI) and acute respiratory distress syndrome (ARDS) in a cohort of children with life-threatening bleeding from all etiologies. METHODS: In a secondary analysis of the prospective observational massive transfusion in children (MATIC) study, multivariable logistic regression was performed in an adjusted analysis to determine if blood product ratios or deficits were independently associated with AKI or ARDS in children with life-threatening bleeding. RESULTS: There were 449 children included with a median (interquartile range, IQR) age of 7.3 years (1.7-14.7). Within 5 days of the life-threatening bleeding event, AKI occurred in 18.5% and ARDS occurred in 20.3% of the subjects. Every 10% increase in the platelet to red blood cell transfusion ratio is independently associated with a 12.7% increase in the odds of AKI (adjusted odds ratio 1.127; 95% confidence interval 1.025-1.239; p-value .013). Subjects with operative or medical etiologies were independently associated with an increased risk of AKI compared to those with traumatic injury. No transfusion-related variables were independently associated with the risk of developing ARDS. CONCLUSION: The use of increased platelet to red blood cell transfusion ratios in children with life-threatening bleeding of any etiology may increase the risk of AKI but not ARDS. Prospective trials are needed to determine if increased platelet use in this cohort increases the risk of AKI to examine possible mechanisms.