Acute Kidney Injury in the Context of COVID-19: An Analysis in Hospitalized Mexican Patients.

During the COVID-19 pandemic, a considerable proportion of patients developed a severe condition that included respiratory failure, shock, or multiple organ dysfunction. Acute Kidney Injury (AKI) has been recognized as a possible cause of severe COVID-19 development. Given this, this study investigates the occurrence and consequences of AKI in Mexican patients to contribute to better knowledge and management of this problem. Methods: Using a retrospective observational cohort methodology, we investigated 313 cases from a cohort of 1019 patients diagnosed with COVID-19 at the IMSS Zacatecas General Hospital of Zone No. 1 in 2020. The prevalence of AKI was determined using the AKIN criteria based on serum creatinine levels and a detailed review of demographic characteristics, medical history, comorbidities, and clinical development. Results: The data showed a 25.30% prevalence of AKI among patients infected with severe COVID-19. Remarkably, these patients with AKI exhibited an advanced age (>65 years), arterial hypertension, a higher number of white blood cells during admission and the hospital stay, and elevated levels of C-reactive protein, serum creatinine, and blood urea nitrogen (BUN). Clinically, patients with AKI had signs of prostration, pneumonia, and the requirement for ventilatory assistance when compared to those without AKI. Finally, those diagnosed with AKI and COVID-19 had a 74% death rate. Relative risk analyses indicated that age (>65 years), arterial hypertension, high creatinine levels, endotracheal intubation, and pneumonia are associated with the development of AKI. On the other hand, among the protective factors against AKI, high hemoglobin levels and the consumption of statins during COVID-19 were found. Conclusions: The findings of this study underscore the significance of promptly identifying and effectively managing AKI to potentially alleviate the negative consequences of this complication within the Mexican population during COVID-19.

Acute Kidney Injury: Gaps and Opportunities for Knowledge and Growth.

Acute kidney injury (AKI) occurs frequently in hospitalized patients, regardless of age or prior medical history. Increasing awareness of the epidemiologic problem of AKI has directly led to increased study of global recognition, diagnostic tools, both reactive and proactive management, and analysis of long-term sequelae. Many gaps remain, however, and in this article we highlight opportunities to add significantly to the increasing bodies of evidence surrounding AKI. Practical considerations related to initiation, prescription, anticoagulation, and monitoring are discussed. In addition, the importance of AKI follow-up evaluation, particularly for those surviving the receipt of renal replacement therapy, is highlighted as a push for global equity in the realm of critical care nephrology is broached. Addressing these gaps presents an opportunity to impact patient care directly and improve patient outcomes.

Deceased-Donor Acute Kidney Injury and Acute Rejection in Kidney Transplant Recipients: A Multicenter Cohort.

RATIONALE & OBJECTIVE: Donor acute kidney injury (AKI) activates innate immunity, enhances HLA expression in the kidney allograft, and provokes recipient alloimmune responses. We hypothesized that injury and inflammation that manifested in deceased-donor urine biomarkers would be associated with higher rates of biopsy-proven acute rejection (BPAR) and allograft failure after transplantation. STUDY DESIGN: Prospective cohort. SETTING & PARTICIPANTS: 862 deceased donors for 1,137 kidney recipients at 13 centers. EXPOSURES: We measured concentrations of interleukin 18 (IL-18), kidney injury molecule 1 (KIM-1), and neutrophil gelatinase-associated lipocalin (NGAL) in deceased donor urine. We also used the Acute Kidney Injury Network (AKIN) criteria to assess donor clinical AKI. OUTCOMES: The primary outcome was a composite of BPAR and graft failure (not from death). A secondary outcome was the composite of BPAR, graft failure, and/or de novo donor-specific antibody (DSA). Outcomes were ascertained in the first posttransplant year. ANALYTICAL APPROACH: Multivariable Fine-Gray models with death as a competing risk. RESULTS: Mean recipient age was 54 ± 13 (SD) years, and 82% received antithymocyte globulin. We found no significant associations between donor urinary IL-18, KIM-1, and NGAL and the primary outcome (subdistribution hazard ratio [HR] for highest vs lowest tertile of 0.76 [95% CI, 0.45-1.28], 1.20 [95% CI, 0.69-2.07], and 1.14 [95% CI, 0.71-1.84], respectively). In secondary analyses, we detected no significant associations between clinically defined AKI and the primary outcome or between donor biomarkers and the composite outcome of BPAR, graft failure, and/or de novo DSA. LIMITATIONS: BPAR was ascertained through for-cause biopsies, not surveillance biopsies. CONCLUSIONS: In a large cohort of kidney recipients who almost all received induction with thymoglobulin, donor injury biomarkers were associated with neither graft failure and rejection nor a secondary outcome that included de novo DSA. These findings provide some reassurance that centers can successfully manage immunological complications using deceased-donor kidneys with AKI.

Acute Kidney Injury in a Cohort of Critical Illness Patients Exposed to Non-Steroidal Anti-Inflammatory Drugs.

To determine whether non-steroidal anti-inflammatory drug (NSAIDs) exposure prior to intensive care unit (ICU) admission affects the development of acute kidney injury (AKI) with renal replacement therapy (RRT). An administrative database is used to establish a cohort of patients who were admitted to the ICU. The exposure to NSAIDs that the patients had before admission to the ICU is determined. Demographic variables, comorbidities, AKI diagnoses requiring RRT, and pneumonia during the ICU stay are also measured. Multivariate logistic regression and inverse probability weighting (IPW) are used to calculate risks of exposure to NSAIDs for patients with AKI requiring RRT. In total, 96,235 patients were admitted to the ICU, of which 16,068 (16.7%) were exposed to NSAIDs. The incidence of AKI with RRT was 2.71% for being exposed to NSAIDs versus 2.24% for those not exposed (p < 0.001). For the outcome of AKI, the odds ratio weighted with IPW was 1.28 (95% CI: 1.15−1.43), and for the outcome of pneumonia as a negative control, the odds ratio was 1.07 (95% CI: 0.98−1.17). The impact of prior exposure to NSAIDs over critically ill patients in the development of AKI is calculated as 8 patients per 1000 exposures. The negative control with the same sources of bias did not show an association with NSAID exposure.

Serum Cystatin C as a predictor of acute kidney injury in neonates: a meta-analysis

Abstract Objective: The objective of this meta-analysis is to evaluate the diagnostic value of serum Cystatin C in acute kidney injury (AKI) in neonates Sources: PubMed, Embase, Cochrane Library, Web of Science, China National Knowledge Infrastructure (CNKI), and WanFang Database were searched to retrieve the literature related to the diagnostic value of Cystatin C for neonatal AKI from inception to May 10, 2021. Subsequently, the quality of included studies was determined using the QUADAS-2 tool. Stata 15.0 statistical software was used to calculate the combined sensitivity (SEN), specificity (SPE), positive likelihood ratio (PLR), negative likelihood ratio (NLR), and diagnostic odds ratio (DOR). Additionally, meta-regression analysis and subgroup analysis contributed to explore the sources of heterogeneity Summary of the findings: Twelve articles were included. The pooled sensitivity was 0.84 (95%CI: 0.74-0.91), the pooled specificity was 0.81 (95%CI: 0.75-0.86), the pooled PLR was 4.39 (95%CI: 3.23-5.97), the pooled NLR was 0.19 (95%CI: 0.11-0.34), and the DOR was 22.58 (95%CI: 10.44-48.83). The area under the receiver operating characteristic curve (AUC) was 0.88 (95%CI: 0.85-0.90). No significant publication bias was identified (p > 0.05).

Severe Acute Kidney Injury Secondary to Immunoglobulin Infusion in Life-Threatening Guillain Barre Syndrome.

Immunoglobulin infusion (IVIG) is one of the first line therapy in Guillain Barre Syndrome (GBS). Several medical complications are associated with GBS (pneumonia, sepsis, deep vein thrombosis, dysautonomy). Acute kidney injury (AKI) is an uncommon complication during IVIG infusion. Several risk factors were associated with AKI during IVIG. These are an older age, previous renal disease, concomitant use of nephrotoxic agents, diabetes mellitus, hypovolemia, sepsis or using of IVIG that contained in its preparation sucrose or mannitol as stabilizers to avoid precipitation and aggregation. Infusion rate and total dose play a determinant role. The most important pathophysiological mechanism of AKI are the osmotic stress applied to the epithelium of proximal tubules and glomeruli. The osmotic overload is principally generated by IVIG stabilizers (sucrose). In general, AKI is reversible but approximately 30% hemodialysis is necessary. It is essential to respect doses, infusion rates and closely monitoring renal function parameters during IVIG infusion.

Serum Cystatin C as a predictor of acute kidney injury in neonates: a meta-analysis.

OBJECTIVES: The objective of this meta-analysis is to evaluate the diagnostic value of serum Cystatin C in acute kidney injury (AKI) in neonates. SOURCES: PubMed, Embase, Cochrane Library, Web of Science, China National Knowledge Infrastructure (CNKI), and WanFang Database were searched to retrieve the literature related to the diagnostic value of Cystatin C for neonatal AKI from inception to May 10, 2021. Subsequently, the quality of included studies was determined using the QUADAS-2 tool. Stata 15.0 statistical software was used to calculate the combined sensitivity (SEN), specificity (SPE), positive likelihood ratio (PLR), negative likelihood ratio (NLR), and diagnostic odds ratio (DOR). Additionally, meta-regression analysis and subgroup analysis contributed to explore the sources of heterogeneity. SUMMARY OF THE FINDINGS: Twelve articles were included. The pooled sensitivity was 0.84 (95%CI: 0.74-0.91), the pooled specificity was 0.81 (95%CI: 0.75-0.86), the pooled PLR was 4.39 (95%CI: 3.23-5.97), the pooled NLR was 0.19 (95%CI: 0.11-0.34), and the DOR was 22.58 (95%CI: 10.44-48.83). The area under the receiver operating characteristic curve (AUC) was 0.88 (95%CI: 0.85-0.90). No significant publication bias was identified (p > 0.05). CONCLUSIONS: Serum Cystatin C has a good performance in predicting neonatal AKI; therefore, it can be used as a candidate biomarker after the optimal level is determined by large prospective studies.

Mitochondrial Redox Signaling and Oxidative Stress in Kidney Diseases.

Mitochondria are essential organelles in physiology and kidney diseases, because they produce cellular energy required to perform their function. During mitochondrial metabolism, reactive oxygen species (ROS) are produced. ROS function as secondary messengers, inducing redox-sensitive post-translational modifications (PTM) in proteins and activating or deactivating different cell signaling pathways. However, in kidney diseases, ROS overproduction causes oxidative stress (OS), inducing mitochondrial dysfunction and altering its metabolism and dynamics. The latter processes are closely related to changes in the cell redox-sensitive signaling pathways, causing inflammation and apoptosis cell death. Although mitochondrial metabolism, ROS production, and OS have been studied in kidney diseases, the role of redox signaling pathways in mitochondria has not been addressed. This review focuses on altering the metabolism and dynamics of mitochondria through the dysregulation of redox-sensitive signaling pathways in kidney diseases.

Clinical assessment and pathophysiology of Bothrops venom-related acute kidney injury: a scoping review.

Bothrops are one of the most common medically important snakes found in Latin America. Its venom is predominantly hemotoxic and proteolytic, which means that local lesion (edema and redness) and hemorrhagic symptoms are recurrent in envenoming by this snake. Although hemorrhage is usually the major cause of death, snakebite-related acute kidney injury is another potentially fatal clinical complication that may lead to chronic kidney disease. The present review highlights the main studies on Bothrops venom-related acute kidney injury, including observational, cross-sectional, case-control and cohort human studies available up to December 2019. The following descriptors were used according to Medical Subject Headings (MeSH): on Medline/Pubmed and Google Scholar "acute kidney injury" or "kidney disease" and "Bothrops"; on Lilacs and SciELO "kidney disease" or "acute kidney injury" and "Bothrops". Newcastle-Ottawa quality assessment scale was used to appraise the quality of the cross-sectional and cohort studies included. The selection of more severe patients who looked for health care units and tertiary centers is a risk of bias. Due to the methodological heterogeneity of the studies, a critical analysis of the results was performed based on the hypothesis that the design of the included studies influences the incidence of acute kidney injury. Fifteen human studies (total participants 4624) were included according to stablished criteria. The coagulation abnormalities (hemorrhagic symptoms, abnormal fibrinogen and activated partial thromboplastin time) were associated with acute kidney injury in the most recent studies reported. The findings observed in this review provide up-to-date evidence about the acute kidney injury pathogenesis following Bothrops syndrome. Studies pointed out that coagulation abnormalities comprise the major pathway for acute kidney injury development. This review may improve patient management by primary healthcare providers, allowing earlier diagnosis and treatment of Bothrops venom-related acute kidney injury.

Clinical assessment and pathophysiology of Bothrops venom-related acute kidney injury: a scoping review

Bothrops are one of the most common medically important snakes found in Latin America. Its venom is predominantly hemotoxic and proteolytic, which means that local lesion (edema and redness) and hemorrhagic symptoms are recurrent in envenoming by this snake. Although hemorrhage is usually the major cause of death, snakebite-related acute kidney injury is another potentially fatal clinical complication that may lead to chronic kidney disease. The present review highlights the main studies on Bothrops venom-related acute kidney injury, including observational, cross-sectional, case-control and cohort human studies available up to December 2019. The following descriptors were used according to Medical Subject Headings (MeSH): on Medline/Pubmed and Google Scholar "acute kidney injury" or "kidney disease" and "Bothrops"; on Lilacs and SciELO "kidney disease" or "acute kidney injury" and "Bothrops". Newcastle-Ottawa quality assessment scale was used to appraise the quality of the cross-sectional and cohort studies included. The selection of more severe patients who looked for health care units and tertiary centers is a risk of bias. Due to the methodological heterogeneity of the studies, a critical analysis of the results was performed based on the hypothesis that the design of the included studies influences the incidence of acute kidney injury. Fifteen human studies (total participants 4624) were included according to stablished criteria. The coagulation abnormalities (hemorrhagic symptoms, abnormal fibrinogen and activated partial thromboplastin time) were associated with acute kidney injury in the most recent studies reported. The findings observed in this review provide up-to-date evidence about the acute kidney injury pathogenesis following Bothrops syndrome. Studies pointed out that coagulation abnormalities comprise the major pathway for acute kidney injury development. This review may improve patient management by primary healthcare providers, allowing earlier diagnosis and treatment of Bothrops venom-related acute kidney injury.(AU)

Clinical assessment and pathophysiology of Bothrops venom-related acute kidney injury: a scoping review

Bothrops are one of the most common medically important snakes found in Latin America. Its venom is predominantly hemotoxic and proteolytic, which means that local lesion (edema and redness) and hemorrhagic symptoms are recurrent in envenoming by this snake. Although hemorrhage is usually the major cause of death, snakebite-related acute kidney injury is another potentially fatal clinical complication that may lead to chronic kidney disease. The present review highlights the main studies on Bothrops venom-related acute kidney injury, including observational, cross-sectional, case-control and cohort human studies available up to December 2019. The following descriptors were used according to Medical Subject Headings (MeSH): on Medline/Pubmed and Google Scholar "acute kidney injury" or "kidney disease" and "Bothrops"; on Lilacs and SciELO "kidney disease" or "acute kidney injury" and "Bothrops". Newcastle-Ottawa quality assessment scale was used to appraise the quality of the cross-sectional and cohort studies included. The selection of more severe patients who looked for health care units and tertiary centers is a risk of bias. Due to the methodological heterogeneity of the studies, a critical analysis of the results was performed based on the hypothesis that the design of the included studies influences the incidence of acute kidney injury. Fifteen human studies (total participants 4624) were included according to stablished criteria. The coagulation abnormalities (hemorrhagic symptoms, abnormal fibrinogen and activated partial thromboplastin time) were associated with acute kidney injury in the most recent studies reported. The findings observed in this review provide up-to-date evidence about the acute kidney injury pathogenesis following Bothrops syndrome. Studies pointed out that coagulation abnormalities comprise the major pathway for acute kidney injury development. This review may improve patient management by primary healthcare providers, allowing earlier diagnosis and treatment of Bothrops venom-related acute kidney injury.(AU)

Inflammation in Renal Diseases: New and Old Players.

Inflammation, a process intimately linked to renal disease, can be defined as a complex network of interactions between renal parenchymal cells and resident immune cells, such as macrophages and dendritic cells, coupled with recruitment of circulating monocytes, lymphocytes, and neutrophils. Once stimulated, these cells activate specialized structures such as Toll-like receptor and Nod-like receptor (NLR). By detecting danger-associated molecules, these receptors can set in motion major innate immunity pathways such as nuclear factor ĸB (NF-ĸB) and NLRP3 inflammasome, causing metabolic reprogramming and phenotype changes of immune and parenchymal cells and triggering the secretion of a number of inflammatory mediators that can cause irreversible tissue damage and functional loss. Growing evidence suggests that this response can be deeply impacted by the crosstalk between the kidneys and other organs, such as the gut. Changes in the composition and/or metabolite production of the gut microbiota can influence inflammation, oxidative stress, and fibrosis, thus offering opportunities to positively manipulate the composition and/or functionality of gut microbiota and, consequentially, ameliorate deleterious consequences of renal diseases. In this review, we summarize the most recent evidence that renal inflammation can be ameliorated by interfering with the gut microbiota through the administration of probiotics, prebiotics, and postbiotics. In addition to these innovative approaches, we address the recent discovery of new targets for drugs long in use in clinical practice. Angiotensin II receptor antagonists, NF-ĸB inhibitors, thiazide diuretics, and antimetabolic drugs can reduce renal macrophage infiltration and slow down the progression of renal disease by mechanisms independent of those usually attributed to these compounds. Allopurinol, an inhibitor of uric acid production, has been shown to decrease renal inflammation by limiting activation of the NLRP3 inflammasome. So far, these protective effects have been shown in experimental studies only. Clinical studies will establish whether these novel strategies can be incorporated into the arsenal of treatments intended to prevent the progression of human disease.

Continuous Renal Replacement Therapy Dosing in the Severely Underweight: A Case Report.

Guidelines recommend that patients treated with continuous renal replacement therapy be delivered an effluent dose of 20 to 25 mL/kg/h. There is debate, especially at the extremes of body mass index, as to whether actual or ideal body weight (IBW) should be used in these dose calculations. A middle-aged woman with severe anorexia presented with 48 hours of altered mental status. Laboratory tests showed severe metabolic acidosis necessitating intubation, which was ultimately found to be due to nonprescribed use of metformin for weight loss. The patient became anuric and was initiated on continuous venovenous hemodialysis. Due to refractory acidosis, the modality was converted to continuous venovenous hemodiafiltration by adding postfilter hypertonic bicarbonate solution. Based on changes in sodium and bicarbonate levels over 4 hours with hypertonic bicarbonate solution, we were able to calculate an "effective" volume of distribution for this severely underweight patient. Our calculations suggest that IBW gives a better approximation of effective volume of distribution than actual body weight in a severely underweight woman. Inadequate effluent flow rate calculated based on actual rather than IBW may lead to insufficient correction of metabolic derangements in extremely underweight patients.

Respiratory parameters and acute kidney injury in acute respiratory distress syndrome: a causal inference study.

BACKGROUND: Assess the respiratory-related parameters associated with subsequent severe acute kidney injury in mechanically ventilated patients with acute respiratory distress syndrome (ARDS). METHODS: Retrospective cohort, analyzing a large public database-Multiparameter Intelligent Monitoring in Intensive Care-III. Adult patients with at least 48 h of mechanical ventilation (MV), under volume controlled ventilation and an oxygenation index less than 300 mmHg were included. RESULTS: A total of 1,142 patients had complete data and were included in the final analyses. According to a causal directed acyclic graph (DAG) that included respiratory system compliance (Crs), tidal volume (Vt), driving pressure (ΔP), plateau pressure (PPlat), PEEP, PaO2 and PaCO2 as possible exposures related to severe AKI, only Crs and PEEP levels had significant causal association with severe acute kidney injury (AKI) (OR 0.90, 95% CI: 0.84-0.94 for each 5-mL/cmH2O reduction in Crs; OR, 1.05 95% CI: 1.03-1.10 for each 1-cmH2O increase of PEEP). Using mediation analysis, we examined whether any mechanical ventilation, blood gas or hemodynamic parameters could explain the effects of Csr on AKI. Only PEEP mediated the significant but small effect (less than 5%) of Csr on severe AKI. The effects of PEEP, in turn, were not mediated by any other evaluated parameter. Several sensitivity analyses with (I) need of renal replacement therapy (RRT) as an alternative outcome and (II) only patients with Vt <8 mL/kg, confirmed our main findings. In trying to validate our DAG assumptions, we confirmed that only ΔP was associated with mortality but not with severe AKI. CONCLUSIONS: Crs and PEEP are the only respiratory-related variables with a direct causal association in severe AKI. No mechanical ventilator or blood gas parameter mediated the effects of Crs. Approaches reducing Vt and/or ΔP in ARDS can have limited effect on renal protection.

Acute Kidney Injury in Sugarcane Workers at Risk for Mesoamerican Nephropathy.

RATIONALE & OBJECTIVE: Mesoamerican nephropathy (MeN), a form of chronic kidney disease (CKD) of unknown cause in Central America, affects young individuals working in physically strenuous occupations. Repeated episodes of work-related kidney injury may lead to CKD in this setting. We aimed to better understand the burden and natural history of acute kidney injury (AKI) in workers at risk for MeN. STUDY DESIGN: Cross-sectional study of active sugarcane workers, followed by prospective follow-up of individuals with AKI. SETTING & PARTICIPANTS: 326 sugarcane workers with normal preharvest serum creatinine (Scr) values and no history of CKD in an MeN hotspot in Nicaragua near the end of the harvest, and prospective follow-up of workers with AKI. PREDICTOR: AKI during the harvest, as defined by Scr level increase ≥ 0.3mg/dL over baseline to a level ≥ 1.3mg/dL. OUTCOMES: Kidney function trajectory and development of CKD over 12 months. ANALYTICAL APPROACH: Linear regression models were used to analyze the association between job category and kidney function. For workers with AKI, the effect of time on Scr level was evaluated using linear mixed effects. RESULTS: 34 of 326 participants were found to have AKI, with a median late-harvest Scr level of 1.64mg/dL in the AKI group. Workers without AKI had a median Scr level of 0.88mg/dL. AKI was more common among cane cutters compared with other field workers. Participants with AKI had variable degrees of kidney function recovery, with median 6- and 12-month Scr values of 1.25 and 1.27mg/dL, respectively (P < 0.001 for each follow-up value compared to late-harvest Scr). When we compared workers' kidney function before the AKI episode to their kidney function at last follow-up, 10 participants with AKI developed de novo estimated glomerular filtration rate < 60mL/min/1.73m2 and 11 had a >30% decrease in estimated glomerular filtration rate. LIMITATIONS: Follow-up limited to 1 year and some loss to follow-up in the prospective component of the study. Broad definition of AKI that includes both acute and subacute kidney injury. CONCLUSIONS: In a group of sugarcane workers with normal preharvest kidney function, newly decreased kidney function developing during the harvest season was common. Of those with kidney injury, nearly half had established CKD 12 months later.

miR-26a modulates HGF and STAT3 effects on the kidney repair process in a glycerol-induced AKI model in rats.

Acute kidney injury is mostly reversible, and hepatocyte growth factor (HGF) has a relevant role in the tissue repair. MicroRNA (miR)-26a is an endogenous modulator of HGF. The role of miR-26a in the kidney repair process was evaluated in Wistar rats submitted to an acute kidney injury model of rhabdomyolysis induced by glycerol (6 mL/kg). Animals were evaluated 3, 12, 48, 96, and 120 hours after glycerol injection. Serum creatinine (SCr) and gene expression of HGF, c-met, signal transducer and activator of transcription 3 (STAT3), and miR-26a were estimated. Also, tubular NK52E cells were transfected with anti-miR26a and stimulated with Fe3+ for 24 hours to mimic the effects of myoglobin in vitro. SCr was highest after 48 hours. After 96 hours, SCr started to decrease, characterizing the recovery phase, with normalization after 120 hours. HGF expression increased during the onset phase (3 hours), with a low relationship with miR-26a. In contrast, in the recovery phase, the increase in miR-26a was coincident with HGF messenger RNA suppression, suggesting that in the recovery phase, miR-26a may have a role in HGF modulation. Fe3+ induced cellular death after 3 hours and proliferation after 24 hours. There was no correlation between miR-26a and STAT3 during the death phase; however, during the proliferation phase, an increase in STAT3 was paralleled with a decrease in miR-26a. miR-26a silencing induced increases in cell viability and the phosphorylated form of STAT3 protein expression in cells receiving Fe3+ . In conclusion, miR-26a may have a key role in modulating HGF levels after its proliferative effects have been triggered.

Atypical Presentation of Pregnancy-Related Hemolytic Uremic Syndrome.

The cause of acute kidney injury during pregnancy and in the postpartum period can be particularly challenging to diagnose, especially when it is necessary to differentiate among preeclampsia; eclampsia; hemolysis, elevated liver enzymes and low platelets (HELLP) syndrome; and thrombotic microangiopathies (TMAs). All these disease entities can present with kidney failure, microangiopathic hemolytic anemia, and thrombocytopenia. We present a teaching case of atypical hemolytic uremic syndrome in the postpartum period in a young woman who was found to have mutations of uncertain clinical significance in the complement cascade, including in C3, CFH, and CFI. We use this as an opportunity to review the clinical presentation and pathophysiology of preeclampsia, eclampsia, and the TMAs. We focus on diagnostic challenges, especially because many patients with TMA do not present with thrombocytopenia, which can delay diagnosis. We additionally review the clinical settings in which administration of eculizumab, a C5 membrane attack complex inhibitor, is appropriate.

Protective outcomes of low-dose doxycycline on renal function of Wistar rats subjected to acute ischemia/reperfusion injury.

Renal ischemia-reperfusion injury (IRI) is a major cause of acute renal failure. Doxycycline (Dc) belongs to the tetracycline-class of antibiotics with demonstrated beneficial molecular effects in the brain and heart, mainly through matrix metalloproteinases inhibition (MMP). However, Dc protection of renal function has not been demonstrated. We determined whether low doses of Dc would prevent decreases in glomerular filtration rate (GFR) and maintain tubular Na+ handling in Wistar rats subjected to kidney I/R. Male Wistar rats underwent bilateral kidney ischemia for 30min followed by 24h reperfusion (I/R). Doxycycline (1, 3, and 10mg/kg, i.p.) was administered 2h before surgery. Untreated I/R rats showed a 250% increase in urine volume and proteinuria, a 60% reduction in GFR, accumulation of urea-nitrogen in the blood, and a 60% decrease in the fractional Na+ excretion due to unbalanced Na+ transporter activity. Treatment with Dc 3mg/kg maintained control levels of urine volume, proteinuria, GFR, blood urea-nitrogen, fractional Na+ excretion, and equilibrated Na+ transporter activities. The Dc protection effects on renal function were associated with kidney structure preservation and prevention of TGFß and fibronectin deposition. In vitro, total MMP activity was augmented in I/R and inhibited by 25 and 50µM Dc. In vivo, I/R augmented MMP-2 and -9 protein content without changing their activities. Doxycycline treatment downregulated total MMP activity and MMP-2 and -9 protein content. Our results suggest that treatment with low dose Dc protects from IRI, thereby preserving kidney function.

The Effect of Spironolactone on Acute Kidney Injury After Cardiac Surgery: A Randomized, Placebo-Controlled Trial.

BACKGROUND: Cardiac surgery-related acute kidney injury (AKI) is a common postoperative complication that greatly increases morbidity and mortality. There are currently no effective interventions to prevent AKI associated with cardiac surgery. Experimental data have shown that administration of the mineralocorticoid receptor blocker spironolactone prevents renal injury induced by ischemia-reperfusion in rats. The objective of this study was to test whether short-term perioperative administration of oral spironolactone could reduce the incidence of AKI in cardiac surgical patients. STUDY DESIGN: Randomized, double-blinded, placebo-controlled trial. SETTING & PARTICIPANTS: Data were collected from April 2014 through July 2015 at the National Heart Institute in Mexico. 233 patients were included; 115 and 118 received spironolactone or placebo, respectively. INTERVENTION: Spironolactone or placebo once at a dose of 100mg 12 to 24 hours before surgery and subsequently 3 further doses of 25mg in postoperative days 0, 1, and 2 were administered. OUTCOMES: Patients were followed up for 7 days or until discharge from the intensive care unit (ICU). The primary end point was AKI incidence defined by KDIGO criteria. Secondary end points included requirement of renal replacement therapy, ICU length of stay, and ICU mortality. Data were analyzed according to the intention-to-treat principle. RESULTS: Mean age was 53.2±15 years, mean serum creatinine level was 0.9±0.2mg/dL, median Thakar score for estimation of AKI risk was 2 (IQR, 1-3), and 25% had diabetes. The incidence of AKI was higher for the spironolactone group (43% vs 29%; P=0.02). No significant differences were found for secondary end points. LIMITATIONS: Single center, AKI was mostly driven by AKI stage 1, planned sample size was not achieved, and there was no renin-angiotensin-aldosterone system washout period. CONCLUSIONS: Our trial demonstrated that spironolactone was not protective for AKI associated with cardiac surgery and there may be a trend toward risk.

Erythropoietin attenuates renal and pulmonary injury in polymicrobial induced-sepsis through EPO-R, VEGF and VEGF-R2 modulation.

Sepsis remains the most important cause of acute kidney injury (AKI) and acute lung injury (ALI) in critically ill patients. The cecal ligation and puncture (CLP) model in experimental mice reproduces most of the clinical features of sepsis. Erythropoietin (EPO) is a well-known cytoprotective multifunctional hormone, which exerts anti-inflammatory, anti-oxidant, anti-apoptotic and pro-angiogenic effects in several tissues. The aim of this study was to evaluate the underlying mechanisms of EPO protection through the expression of the EPO/EPO receptor (EPO-R) and VEGF/VEF-R2 systems in kidneys and lungs of mice undergoing CLP-induced sepsis. Male inbred Balb/c mice were divided in three experimental groups: Sham, CLP, and CLP+EPO (3000IU/kg sc). Assessment of renal functional parameters, survival, histological examination, immunohistochemistry and/or Western blottings of EPO-R, VEGF and VEGF-R2 were performed at 18h post-surgery. Mice demonstrated AKI by elevation of serum creatinine and renal histologic damage. EPO treatment attenuates renal dysfunction and ameliorates kidney histopathologic changes. Additionally, EPO administration attenuates deleterious septic damage in renal cortex through the overexpression of EPO-R in tubular interstitial cells and the overexpression of the pair VEGF/VEGF-R2. Similarly CLP- induced ALI, as evidenced by parenchymal lung histopathologic alterations, was ameliorated through pulmonary EPO-R, VEGF and VEGF-R2 over expression suggesting and improvement in endothelial survival and functionality. This study demonstrates that EPO exerts protective effects in kidneys and lungs in mice with CLP-induced sepsis through the expression of EPO-R and the regulation of the VEGF/VEGF-R2 pair.