Fisiopatología de la insuficiencia renal aguda durante la sepsis

Acute Kidney Injury: Definition, Management, and Promising Therapeutic Target

Acute kidney injury (AKI) is caused by a sudden loss of renal function, resulting in the build-up of waste products and a significant increase in mortality and morbidity. It is commonly diagnosed in critically ill patients, with its occurrence estimated at up to 50% in patients hospitalized in the intensive critical unit. Despite ongoing efforts, the death rate associated with AKI has remained high over the past half-century. Thus, it is critical to investigate novel therapy options for preventing the epidemic. Many studies have found that inflammation and Toll-like receptor-4 (TLR-4) activation have a significant role in the pathogenesis of AKI. Noteworthy, challenges in the search for efficient pharmacological therapy for AKI have arisen due to the multifaceted origin and complexity of the clinical history of people with the disease. This article focuses on kidney injury's epidemiology, risk factors, and pathophysiological processes. Specifically, it focuses on the role of TLRs especially type 4 in disease development.

Anemia and Hypoxia Impact on Chronic Kidney Disease Onset and Progression: Review and Updates

Chronic kidney disease (CKD) is caused by hypoxia in the renal tissue, leading to inflammation and increased migration of pathogenic cells. Studies showed that leukocytes directly sense hypoxia and respond by initiating gene transcription, encoding the 2-integrin adhesion molecules. Moreover, other mechanisms participate in hypoxia, including anemia. CKD-associated anemia is common, which induces and worsens hypoxia, contributing to CKD progression. Anemia correction can slow CKD progression, but it should be cautiously approached. In this comprehensive review, the underlying pathophysiology mechanisms and the impact of renal tissue hypoxia and anemia in CKD onset and progression will be reviewed and discussed in detail. Searching for the latest updates in PubMed Central, Medline, PubMed database, Google Scholar, and Google search engines were conducted for original studies, including cross-sectional studies, cohort studies, clinical trials, and review articles using different keywords, phrases, and texts such as "CKD progression, anemia in CKD, CKD, anemia effect on CKD progression, anemia effect on CKD progression, and hypoxia and CKD progression". Kidney tissue hypoxia and anemia have an impact on CKD onset and progression. Hypoxia causes nephron cell death, enhancing fibrosis by increasing interstitium protein deposition, inflammatory cell activation, and apoptosis. Severe anemia correction improves life quality and may delay CKD progression. Detection and avoidance of the risk factors of hypoxia prevent recurrent acute kidney injury (AKI) and reduce the CKD rate. A better understanding of kidney hypoxia would prevent AKI and CKD and lead to new therapeutic strategies.

Phytocompounds from Amazonian Plant Species against Acute Kidney Injury: Potential Nephroprotective Effects

There are several Amazonian plant species with potential pharmacological validation for the treatment of acute kidney injury, a condition in which the kidneys are unable to adequately filter the blood, resulting in the accumulation of toxins and waste in the body. Scientific production on plant compounds capable of preventing or attenuating acute kidney injury-caused by several factors, including ischemia, toxins, and inflammation-has shown promising results in animal models of acute kidney injury and some preliminary studies in humans. Despite the popular use of Amazonian plant species for kidney disorders, further pharmacological studies are needed to identify active compounds and subsequently conduct more complex preclinical trials. This article is a brief review of phytocompounds with potential nephroprotective effects against acute kidney injury (AKI). The classes of Amazonian plant compounds with significant biological activity most evident in the consulted literature were alkaloids, flavonoids, tannins, steroids, and terpenoids. An expressive phytochemical and pharmacological relevance of the studied species was identified, although with insufficiently explored potential, mainly in the face of AKI, a clinical condition with high morbidity and mortality.

Sepsis-mediated renal dysfunction: Pathophysiology, biomarkers and role of phytoconstituents in its management

Sepsis has evolved as an enormous health issue amongst critically ill patients. It is a major risk factor that results in multiple organ failure and shock. Acute kidney injury (AKI) is one of the most frequent complications underlying sepsis, which portends a heavy burden of mortality and morbidity. Thus, the present review is aimed to provide an insight into the recent progression in the molecular mechanisms targeting dysregulated immune response and cellular dysfunction involved in the development of sepsis-associated AKI, accentuating the phytoconstituents as eligible candidates for attenuating the onset and progression of sepsis-associated AKI. The pathogenesis of sepsis-mediated AKI entails a complicated mechanism and is likely to involve a distinct constellation of hemodynamic, inflammatory, and immune mechanisms. Novel biomarkers like neutrophil gelatinase-associated lipocalin, soluble triggering receptor expressed on myeloid cells 1, procalcitonin, alpha-1-microglobulin, and presepsin can help in a more sensitive diagnosis of sepsis-associated AKI. Many bioactive compounds like curcumin, resveratrol, baicalin, quercetin, and polydatin are reported to play an important role in the prevention and management of sepsis-associated AKI by decreasing serum creatinine, blood urea nitrogen, cystatin C, lipid peroxidation, oxidative stress, IL-1β, TNF-α, NF-κB, and increasing the activity of antioxidant enzymes and level of PPARγ. The plant bioactive compounds could be developed into a drug-developing candidate in managing sepsis-mediated acute kidney injury after detailed follow-up studies. Lastly, the gut-kidney axis may be a more promising therapeutic target against the onset of septic AKI, but a deeper understanding of the molecular pathways is still required.

The association between continuous renal replacement therapy as treatment for sepsis-associated acute kidney injury and trend of lactate trajectory as risk factor of 28-day mortality in intensive care units

BACKGROUND

Sepsis has high incidence and fatality rates in intensive care units, often leading to renal failure. The effectiveness of continuous renal replacement therapy (CRRT) in sepsis-associated acute kidney injury (S-AKI) patients is currently uncertain.

AIM

Joint model was used to determine the association between CRRT and the lactate trajectory trend and how it correlated to 28-day mortality for S-AKI patient in ICU.

METHODS

A retrospective study was applied to patients with sepsis and AKI, which were extracted from the MIMIC-III public database, with the endpoint being 28-day mortality. Every lactate level measurement within 28 days was observed and calculated using logarithms. Joint model combined the longitudinal analysis of the natural logarithm of the lactate level [log(lactate)] in longitudinal submodel and Cox regression by trajectory function, demonstrating the effects of CRRT on 28-day survival and log(lactate) changes, and its final relationship with the event status.

RESULTS

Among the 717 S-AKI patients, 157 received CRRT. CRRT was not associated with 28-day mortality. After adjustments, the relationship between CRRT use and log(lactate) elevation was statistically significant. The parameter estimation of CRRT and log(lactate) indicated that using CRRT will increase log(lactate) by 0.041 in S-AKI patients. The joint model also instigated a fixed association between changes in the lactate level and the event result, revealing an exp value of (0.755) = 2.12, indicating that an increase of one unit in log(lactate) will increase the risk of 28-day mortality 2.12-times.

CONCLUSION

There was no significant association between CRRT use and 28-day survival in S-AKI patients, and JM showed that CRRT use might be associated with elevation of longitudinal lactate levels. Therefore, additional attention should be paid to other treatments to control lactate levels when providing renal support for patients with S-AKI.

A prediction model of sepsis-associated acute kidney injury based on antithrombin III

The incidence of sepsis-associated acute kidney injury (AKI) is on the rise. Recent studies have found a correlation between antithrombin III and AKI. We established a predictive model for sepsis-associated AKI based on plasma ATIII levels. A prospective study (March 2018-January 2020) was conducted in sepsis patients admitted to the Critical Care Medicine Department at Shanghai General Hospital. ATIII levels were obtained within 48 h after admission to the ICU and before the diagnosis of sepsis-associated AKI was recorded. Renal function was assessed by measuring serum creatinine levels and urine volume. Male sex, other cardiovascular disease, and low ATIII levels were identified as independent risk factors for AKI. Age, immune disease, and low ATIII levels were identified as independent risk factors for death. Plasma ATIII levels in the non-AKI group were higher than those in the AKI group, plasma ATIII levels were higher in the survival group than in the non-survival group, plasma ATIII levels in the non-CRRT group were higher than those in the CRRT group, and plasma ATIII levels in the non-CKD group were higher than those in the CKD group. ATIII was significantly higher in the group with pulmonary infection than in the group without pulmonary infection. ATIII was significantly lower in the celiac infection group than in the nonceliac infection group. There was no statistically significant difference between the ATIII in the gram-positive group and the gram-negative group. ATIII was significantly higher in medical patients than in surgical patients. The predictive model of sepsis-associated AKI established based on ATIII was ln[P/(1 - p)] = -1.211 × sex - 0.017 × ATIII + 0.022 × Cr + 0.004 × BUN - 2.8192. The model goodness-of-fit test (p = 0.000) and the area under the ROC curve of the model (0.9862) suggested that the model has a high degree of discrimination and calibration. ATIII reduction was closely related to the prognosis of patients with sepsis. ATIII reduction was an independent risk factor for sepsis-associated AKI and an independent risk factor for mortality in patients with sepsis. ATIII reduction could predict sepsis-associated AKI. Low ATIII predicted a poor prognosis.

Antithrombin III expression predicts acute kidney injury in elderly patients with sepsis

Elderly people represent the age group most frequently affected by acute kidney injury (AKI). The potential of Antithrombin III (ATIII) level for predicting AKI among elderly patients with sepsis is yet to be elucidated. Therefore, the purpose of the present study was to evaluate the ability of ATIII to predict AKI nondevelopment and prognosis in elderly patients with sepsis, in an intensive care unit (ICU). The present study was retrospective and included 107 elderly patients with sepsis who had been admitted to ICUs between October 2015 and March 2018. An assessment of renal function was performed daily by measuring serum creatinine (Cr) level and urine output, and ATIII level was obtained within 48 h of sepsis diagnosis. Among all enrolled patients, 29 (27.1%) developed AKI. ATIII expression was a predictor of AKI nondevelopment [Area under the curve (AUC)-Receiving operator characteristic (ROC)=0.729; sensitivity, 0.700; specificity, 0.714], and the ATIII/Creatine ratio was also a predictor of AKI nondevelopment (AUC-ROC=0.971; sensitivity, 0.900; specificity, 1). The accuracy of ATIII (AUC-ROC=0.681; sensitivity, 0.802; specificity, 0.542) and ATIII/Cr (AUC-ROC=0.804; sensitivity, 0.596; specificity, 0.875) in predicting survival was intermediate. However, the ATIII serum level was able to accurately predict AKI nondevelopment in elderly patients with sepsis, who were admitted to ICUs. Patients were divided into low- and high-ATIII groups using either 66.95% or 55.7% as cut-off values, both of which were used for further analysis. By comparison, the ICU stay was significantly lower in the high-ATIII group [P=0.020 (69.95%) and 0.049 (55.7%)] and off mechanical ventilation time, off continuous renal replacement therapy time and survival time were significantly higher in the high ATIII group [P=0.049, 0.048, and 0.014, respectively (66.95%); and P=0.041, 0.036, and 0.021, respectively (55.7%)]. The current study indicated that ATIII serum level predicts AKI in elderly patients with sepsis, and that low ATIII levels predicted a poorer prognosis.

Role of microRNA in the detection, progression, and intervention of acute kidney injury

Acute kidney injury, characterized by sharply decreased renal function, is a common and important complication in hospitalized patients. The pathological mechanism of acute kidney injury is mainly related to immune activation and inflammation. Given the high morbidity and mortality rates of hospitalized patients with acute kidney injury, the identification of biomarkers useful for assessing risk, making an early diagnosis, evaluating the prognosis, and classifying the injury severity is urgently needed. Furthermore, investigation into the development of acute kidney injury and potential therapeutic targets is required. While microRNA was first discovered in Caenorhabditis elegans, Gary Ruvkun's laboratory identified the first microRNA target gene. Together, these two important findings confirmed the existence of a novel post-transcriptional gene regulatory mechanism. Considering that serum creatinine tests often fail in the early detection of AKI, testing for microRNAs as early diagnostic biomarkers has shown great potential. Numerous studies have identified microRNAs that can serve as biomarkers for the detection of acute kidney injury. In addition, as microRNAs can control the expression of multiple proteins through hundreds or thousands of targets influencing multiple signaling pathways, the number of studies on the functions of microRNAs in AKI progression is increasing. Here, we mainly focus on research into microRNAs as biomarkers and explorations of their functions in acute kidney injury. Impact statement Firstly, we have discussed the potential advantages and limitations of miRNA as biomarkers. Secondly, we have summarized the role of miRNA in the progress of AKI. Finally, we have made a vision of miRNA's potential and advantages as therapeutic target intervention AKI.

The assessment of acute kidney injury in critically ill patients

Acute kidney injury (AKI) is common in critically ill patients and is associated with high morbidity and mortality. The availability of several biomarkers of kidney injury offers new tools for its early recognition and management. The early identification of high-risk patients provides an opportunity to develop strategies for the prevention, early diagnosis and treatment of AKI. Despite progress in critical care medicine over the past decade, the treatment strategies for AKI in critically ill patients, such as when to start renal replacement therapy, remain controversial. A recently proposed risk prediction score for AKI, based on routinely available clinical variables, presents a new means of identifying patients at high risk of AKI.

Epidemiology of acute kidney injury and chronic kidney disease in the intensive care unit

OBJECTIVE

To describe the epidemiology of acute kidney injury, its relationship to chronic kidney disease, and the factors associated with its incidence.

METHODS

A cohort study and follow-up were conducted in an intensive care unit in Montevideo, Uruguay. We included patients admitted between November 2014 and October 2015 who were older than 15 years of age and who had at least two measurements of serum creatinine. We excluded patients who were hospitalized for less than 48 hours, patients who died at the time of hospitalization, and patients with chronic renal disease who were on hemodialysis or peritoneal dialysis. There were no interventions. Acute kidney injury was defined according to the criteria set forth in Acute Kidney Injury Disease: Improving Global Outcomes, and chronic kidney disease was defined according to the Chronic Kidney Disease Work Group.

RESULTS

We included 401 patients, 56.6% male, median age of 68 years (interquartile range (IQR) 51-79 years). The diagnosis at admission was severe sepsis 36.3%, neurocritical 16.3%, polytrauma 15.2%, and other 32.2%. The incidence of acute kidney injury was 50.1%, and 14.1% of the patients suffered from chronic kidney disease. The incidence of acute septic kidney injury was 75.3%. Mortality in patients with or without acute kidney injury was 41.8% and 14%, respectively (p < 0.001). In the multivariate analysis, the most significant variables for acute kidney injury were chronic kidney disease (odds ratio (OR) 5.39, 95%CI 2.04 - 14.29, p = 0.001), shock (OR 3.94, 95%CI 1.72 - 9.07, p = 0.001), and severe sepsis (OR 7.79, 95%CI 2.02 - 29.97, p = 0.003).

CONCLUSION

The incidence of acute kidney injury is high mainly in septic patients. Chronic kidney disease was independently associated with the development of acute kidney injury.

Inhibition of ALDH2 expression aggravates renal injury in a rat sepsis syndrome model

Mitochondrial aldehyde dehydrogenase 2 (ALDH2) is closely associated with organ injury. The aim of the present study was to investigate the change of ALDH2 expression in a rat model of sepsis-induced acute renal injury, and to observe the effect of ALDH2 inhibition on the kidney. A model of sepsis syndrome was established in Sprague-Dawley (SD) rats by cecal ligation and puncture (CLP). The rats were divided into sham, CLP and CLP + cyanamide (CYA, an ALDH2 inhibitor) groups. The hemodynamic parameters heart rate (HR) and mean arterial blood pressure (MABP) were measured. Plasma creatinine (CRE) and urea nitrogen (BUN) levels were measured using an automatic biochemical analyzer. Malondialdehyde (MDA) content and superoxide dismutase (SOD) activity in the kidney tissue were measured. Histological changes of the kidney tissue were observed using hematoxylin and eosin staining and NF-κB p65 expression was observed by an immunohistochemical staining method. The expression of renal ALDH2 at the mRNA and protein levels was detected by reverse transcription-polymerase chain reaction and western blotting. In the CLP compared with the sham group after 24 h, the MABP was decreased, plasma CRE and BUN levels were elevated, the renal MDA level was increased and SOD activity was decreased. In addition, glomerular atrophy occurred, the renal protein expression of NF-κB p65 was increased, and the mRNA and protein expression levels of ALDH2 were decreased. In contrast with the CLP group, in the CLP + CYA group, the MABP and ALDH2 expression were further decreased while glomerular atrophy was aggravated. Furthermore, CRE, BUN, MDA levels and NF-κB p65 expression were further increased and SOD activity was further reduced. In this rat model of sepsis syndrome, the reduction of renal ALDH2 expression was accompanied by kidney injury. Inhibition of ALDH2 with CYA aggravated the renal injury, and was associated with the overproduction of reactive oxygen species and inflammatory reaction.

Acute kidney injury: Renal disease in the ICU

Acute kidney injury (AKI) in the ICU frequently requires costly supportive therapies, has high morbidity, and its long-term prognosis is not as good as it has been presumed so far. Consequently, AKI generates a significant burden for the healthcare system. The problem is that AKI lacks an effective treatment and the best approach relies on early secondary prevention. Therefore, to facilitate early diagnosis, a broader definition of AKI should be established, and a marker with more sensitivity and early-detection capacity than serum creatinine - the most common marker of AKI - should be identified. Fortunately, new classification systems (RIFLE, AKIN or KDIGO) have been developed to solve these problems, and the discovery of new biomarkers for kidney injury will hopefully change the way we approach renal patients. As a first step, the concept of renal failure has changed from being a "static" disease to being a "dynamic process" that requires continuous evaluation of kidney function adapted to the reality of the ICU patient.

Omega-9 Oleic Acid Induces Fatty Acid Oxidation and Decreases Organ Dysfunction and Mortality in Experimental Sepsis

Sepsis is characterized by inflammatory and metabolic alterations, which lead to massive cytokine production, oxidative stress and organ dysfunction. In severe systemic inflammatory response syndrome, plasma non-esterified fatty acids (NEFA) are increased. Several NEFA are deleterious to cells, activate Toll-like receptors and inhibit Na⁺/K⁺-ATPase, causing lung injury. A Mediterranean diet rich in olive oil is beneficial. The main component of olive oil is omega-9 oleic acid (OA), a monounsaturated fatty acid (MUFA). We analyzed the effect of OA supplementation on sepsis. OA ameliorated clinical symptoms, increased the survival rate, prevented liver and kidney injury and decreased NEFA plasma levels in mice subjected to cecal ligation and puncture (CLP). OA did not alter food intake and weight gain but diminished reactive oxygen species (ROS) production and NEFA plasma levels. Carnitine palmitoyltransferase IA (CPT1A) mRNA levels were increased, while uncoupling protein 2 (UCP2) liver expression was enhanced in mice treated with OA. OA also inhibited the decrease in 5' AMP-activated protein kinase (AMPK) expression and increased the enzyme expression in the liver of OA-treated mice compared to septic animals. We showed that OA pretreatment decreased NEFA concentration and increased CPT1A and UCP2 and AMPK levels, decreasing ROS production. We suggest that OA has a beneficial role in sepsis by decreasing metabolic dysfunction, supporting the benefits of diets high in monounsaturated fatty acids (MUFA).

Adhesion molecules involved in neutrophil recruitment during sepsis-induced acute kidney injury

Acute kidney injury (AKI) is a common complication in critically ill patients and is associated with high mortality. Recruitment of neutrophils is a hallmark in the pathogenesis of AKI. Although ischemia-reperfusion injury (IRI) is a frequently used research model of AKI, the clinical relevance of IRI-induced AKI is limited. Epidemiologically, sepsis is the prevailing cause of kidney injury. However, it is still unknown whether these distinct entities of AKI share the same pathophysiological mechanisms. This study was initiated to investigate the molecular mechanisms of neutrophil recruitment into the kidney in a murine model of sepsis-induced AKI. By using a flow cytometry-based method, we show that the two β2-integrins Mac-1 and LFA-1 as well as E-selectin and P-selectin are involved in neutrophil recruitment into the kidney after induction of sepsis. The molecular mechanisms of neutrophil recruitment were further investigated using intravital microscopy, demonstrating that blocking one of these four molecules reduces the number of adherent leukocytes. This was accompanied by a renal upregulation of E-selectin, P-selectin and ICAM-1 (the counter-receptor of β2-integrins on endothelial cells) after sepsis induction. We conclude that blocking P-selectin, E-selectin, Mac-1 or LFA-1 protects mice from sepsis-induced AKI.

[Analysis of neutrophil gelatinase-associated lipocalin in the critical patient]

OBJECTIVE

To determine if NGAL value exceeding 150 ng/mL is a good diagnostic test for acute renal failure in critically ill patients.

DESIGN

Prospective, observational cohort.

SETTING

Intensive Care Unit and Cardiac Surgery Intensive Care Service at Hospital Germans Trias I Pujol.

PARTICIPANTS

Patients admitted to the Intensive Care department the Designated days in the studio.

INTERVENTIONS

Analysis of serum creatinine blood given from 7 days prior to the start of the study, and daily during 4 weeks and by determination of NGAL urine test in frozen sample, analyzer ARCHITECT (Abbott Diagnostics) determined by immunoassay the day baseline and 2 times a week for 4 weeks, analysis of the stay and mortality.

RESULTS

A total of 529 NGAL samples were obtained from 46 patients. 37% of patients had a value of NGAL>150 ng/mL. The Sensivity of the test to diagnose acute renal failure was 69%, Specifity was 75,7%. However, the Positive Predictive Test Value was 53%, which means that 47% of patients with high NGAL did not develop AKI. A NGAL >150 mg/dL was associated with a significantly higher SOFA and a longer stay in the ICU. The mortality of patients with elevated NGAL was 58.8%.

CONCLUSIONS

A NGAL>150 ng/mL does not seem to be an excellent test for AKI in critically ill patients but is associated with a worse prognosis.

[The sepsis as cause of acute kidney injury: an experimental model]

Sepsis associated with multiple organ failure such as acute kidney injury (AKI) shows a high mortality rate in critically ill patients. This study investigated the sepsis induced AKI in experimental models. Adult, males, Wistar rats divided into the following groups: Control-surgical control and Sepsis-sepsis induction for the cecal ligation and puncture (CLP). Physiological parameters (rectal temperature, mean arterial pressure-MAP, serum glucose and urinary flow); renal function (creatinine clearance); oxidative stress (urinary peroxides and thiobarbituric acid reactive substances-TBARS) and kidney histological analysis were evaluated. That study concludes that sepsis induces AKI by endothelial injury with hemodynamic dysfunction, release of inflammatory mediators and reactive oxygen species (ROS) generation by tubular cells, in an association of renal vasoconstriction due to hemodynamic and inflammatory disturbances.

Case-Control Study of Nutritional Antioxidant Intake in Essential Tremor

The theory that oxidative stress is involved in the pathogenesis of neurodegenerative diseases has received considerable attention and studies have linked these diseases to the diminished use of antioxidant vitamins (vitamins E and C) and other dietary antioxidants. Essential tremor (ET) is a chronic, progressive disease. One possible disease mechanism is neurodegenerative. Whether nutritional antioxidant use differs between ET cases and controls is not known. Using a case-control design, we conducted detailed dietary assessments and tested the hypothesis that diminished use of nutritional antioxidants is associated with ET. Data on diet were collected on 156 ET cases and 220 controls using a semi-quantitative food-frequency questionnaire. There was no evidence that current nutritional antioxidant exposure differs in ET cases and controls. This does not exclude the possibility that nutritional antioxidant exposure was lower in ET cases prior to their disease onset.