Markers of acute kidney injury in patients with sepsis: the role of soluble thrombomodulin

E-selectin in vascular pathophysiology

Selectins are a group of Ca2+-dependent, transmembrane type I glycoproteins which attract cell adhesion and migration. E-selectin is exclusively expressed in endothelial cells, and its expression is strongly enhanced upon activation by pro-inflammatory cytokines. The interaction of E-selectin with its ligands on circulating leukocytes captures and slows them down, further facilitating integrin activation, firm adhesion to endothelial cells and transmigration to tissues. Oxidative stress induces endothelial cell injury, leading to aberrant expression of E-selectin. In addition, the elevated level of E-selectin is positively related to high risk of inflammation. Dysregulation of E-selectin has been found in several pathological conditions including acute kidney injury (AKI), pulmonary diseases, hepatic pathology, Venous thromboembolism (VTE). Deletion of the E-selectin gene in mice somewhat ameliorates these complications. In this review, we describe the mechanisms regulating E-selectin expression, the interaction of E-selectin with its ligands, the E-selectin physiological and pathophysiological roles, and the therapeutical potential of targeting E-selectin.

Association between systemic inflammation biomarkers and mortality in patients with sepsis-associated acute kidney injury receiving intensive care and continuous kidney replacement therapy: results from the RENERGY (REsearches for NEphRology and epidemioloGY) study

BACKGROUND

Identifying risk factors and improving prognostication for mortality among patients with sepsis-associated acute kidney injury (AKI) undergoing continuous kidney replacement therapy (CKRT) is important in improving the adverse prognosis of this patient population. This study aimed to compare the prognostic value of existing systemic inflammation biomarkers and determine the optimal systemic inflammation biomarker in patients with sepsis-associated AKI receiving CKRT.

METHODS

This multi-center, retrospective, observational cohort study included 1,500 patients with sepsis-associated AKI treated with intensive care and CKRT. The main predictor was a panel of 13 different systemic inflammation biomarkers. The primary outcome was 28-day mortality after CKRT initiation. Secondary outcomes included 90-day mortality after CKRT initiation, CKRT duration, kidney replacement therapy dependence at discharge, and lengths of intensive care unit (ICU) and hospital stays.

RESULTS

When added to the widely accepted Acute Physiology and Chronic Health Evaluation II score, platelet-to-albumin ratio (PAR) and neutrophil-platelet score (NPS) had the highest improvements in prognostication of 28-day mortality, where the corresponding increases in C-statistic were 0.01 (95% confidence interval [CI], 0.00-0.02) and 0.02 (95% CI, 0.01-0.03). Similar findings were observed for 90-day mortality. The 28- and 90-day mortality rates were significantly lower for the higher PAR and NPS quartiles. These associations remained significant even after adjustment for potential confounding variables in multivariable Cox proportional hazards models.

CONCLUSION

Of the available systemic inflammation biomarkers, the addition of PAR or NPS to conventional ICU prediction models improved the prognostication of patients with sepsis-associated AKI receiving intensive care and CKRT.

Eriocitrin prevents Sepsis-induced acute kidney injury through anti-inflammation and anti-oxidation via modulating Nrf2/DRP1/OPA1 signaling pathway

BACKGROUND

Severe inflammation and oxidative stress are characteristics of sepsis-associated kidney injury with high morbidity and mortality. Eriocitrin (ERI) has shown promise in suppressing sepsis-associated kidney injury and LPS-induced periodontal disease, however, its efficacy in alleviating SAKI remains unexplored. This study aimed to investigate the therapeutic potential of ERI on SAKI through in vivo and in vitro experiments, elucidating its underlying mechanism.

METHODS

The therapeutic effects of ERI against SAKI were evaluated by survival rate, changes of serum creatinine (Scr) and blood urea nitrogen (BUN) and statistic of renal histological score in a Cecal ligation and puncture (CLP)-induced septic mice. Impactions about anti-coagulation, anti-inflammation, anti-oxidative stress and improvement of mitochondrial damage and mitochondrial morphology were further assayed. In vitro, HUVECs upon stimulation of LPS with or without different dosage of ERI, followed by evaluating changes in inflammation, mitochondrial dynamic equilibrium and signaling pathways.

RESULTS

ERI demonstrated ameliorative effects on SAKI by attenuating inflammation, oxidative stress and coagulation evidenced by the improved survival rate, alleviated kidney histological injury, declined BUN and Scr in serum and diminished levels of inflammation cytokines, and coagulation factors. Mechanistically, ERI suppressed DRP1-regulated mitochondrial fission and promoted OPA1-modulated mitochondrial fusion by activating Nrf2 in septic mice and LPS-stimulated HUVECs, which maintained mitochondrial dynamic equilibrium, improved mitochondrial morphology, assured integrity of mitochondrial function, decreased oxidative stress, impeded overwhelming inflammation, and thus, played a pivotal role in ERI's protection against SAKI.

CONCLUSION

Our data confirmed the therapeutic potential of ERI in mitigating SAKI，suggesting its viability as a pharmacological agent in clinic settings.

The role of thromboinflammation in acute kidney injury among patients with septic coagulopathy

Inflammation and coagulation are critical self-defense mechanisms for mitigating infection that can nonetheless induce tissue injury and organ dysfunction. In severe cases, like sepsis, a dysregulated thromboinflammatory response may result in multiorgan dysfunction. Sepsis-associated acute kidney injury (AKI) is a significant contributor to patient morbidity and mortality. The connection between AKI and thromboinflammation is largely due to unique aspects of the renal vasculature. Specifically, the interaction between blood cells with the endothelial, glomerular, and peritubular capillary systems during thromboinflammation reduces oxygen supply to tubular epithelial cells. Previous studies have focused on tubular epithelial cell damage due to hypoxia, oxidative stress, and nephrotoxins. Although these factors are pivotal in acute tubular injury or necrosis, recent studies have demonstrated that AKI in sepsis encompasses a mixture of tubular and glomerular damage subtypes. In cases of sepsis-induced coagulopathy, thromboinflammation within the glomerulus and peritubular capillaries is an important pathogenic mechanism for AKI. Unfortunately, and despite the use of renal replacement therapy, the development of AKI in sepsis continues to be associated with high morbidity, mortality, and clinical challenges requiring alternative approaches. This review introduces the important role of thromboinflammation in AKI pathogenesis and details innovative vascular-targeting therapeutic strategies.

Comparison of diagnostic criteria for sepsis-associated acute kidney injury in the pediatric intensive care unit: a retrospective cohort study

Background

pRIFLE (Pediatric Risk, Injury, Failure, Loss, End Stage Renal Disease), KDIGO (Kidney Disease Improving Global Outcomes) and pROCK (Pediatric Reference Change Value Optimized for AKI) are diagnostic criteria used for acute kidney injury (AKI) incidence evaluation. The aim of this study was to explore the diagnostic consistency, incidence and mortality rate, clinical signs, and influencing factors of renal injury related to sepsis in children diagnosed by three different AKI diagnostic criteria, and then evaluate which one was more valuable.

Methods

A retrospective analysis was performed on the clinical data of children with severe sepsis. The patients were diagnosed and staged according to the 2007 pRIFLE standard, the 2012 KDIGO standard, and the 2018 pROCK standard. The clinical characteristics and prognosis of children with different stages of sepsis were compared between the three diagnostic standards.

Results

A total of 62 patients with sepsis were included. Blood stream infection is common (11 cases, 17.74%). According to pRIFLE, KDIGO, and pROCK standards, the incidence of sepsis-associated AKI (SA-AKI) was 74.2%, 67.7%, and 56.5%, respectively. The pRIFLE had the highest diagnostic rate of early detection of SA-AKI. There was no statistical difference in SA-AKI incidence or staging consistency between the pRIFLE and KDIGO groups (κ=0.0671; κ>0.60); the consistency of SA-AKI diagnoses across the three standards was good (all P values <0.05), and pROCK demonstrated a higher specificity. A high Pediatric Risk of Mortality (PRISM) score and high procalcitonin level were independent risk factors. Shock and renal replacement therapy were independent risk factors for SA-AKI death. Death from admission to 28 days after admission was used as an endpoint to draw a survival graph, which revealed that the AKI group had a significantly higher risk of death than did the non-AKI group.

Conclusions

The consistency of diagnosing SA-AKI across the three classification criteria was similar, and mortality rate increased with increased SA-AKI staging. The pRIFLE criteria were more sensitive in the early detection of SA-AKI, while the pROCK had higher specificity. There was no significant difference between the pRIFLE and KDIGO in terms of incidence, diagnosis, or staging of SA-AKI.

Acute respiratory distress syndrome, acute kidney injury, and mortality after trauma are associated with increased circulation of syndecan-1, soluble thrombomodulin, and receptor for advanced glycation end products

BACKGROUND

Disruption of the vascular endothelium and endothelial glycocalyx (EG) has been described after severe trauma. Plasma has been suggested to restore microvascular integrity by preservation and repair of the EG. We sought to evaluate whether plasma administered in a 1:1:1 ratio was associated with less endothelial marker circulation than a 1:1:2 ratio.

METHODS

This is a secondary analysis of the PROPPR trial, which investigated post-traumatic resuscitation with platelets, plasma, and red blood cells in a 1:1:1 ratio compared with a 1:1:2 ratio. Syndecan-1, soluble thrombomodulin (sTM), and receptor for advanced glycation end products (RAGE) were quantified for each treatment group on admission and at 2 hours, 4 hours, 6 hours, 12 hours, 24 hours, 48 hours, and 72 hours. Patients were excluded if they did not survive longer than 3 hours or had data from fewer than two time points.

RESULTS

Three hundred eight patients in the 1:1:1 group and 291 in the 1:1:2 group were analyzed. There were no statistically significant differences in syndecan-1, sTM, or RAGE between treatment groups at any time point ( p > 0.05). Patients who developed acute respiratory distress syndrome, acute kidney injury, and death had significantly elevated biomarker expression at most time points when compared with patients who did not develop these sequelae ( p < 0.05).

CONCLUSION

Administration of FFP in a 1:1:1 ratio does not consistently affect circulation of endothelial biomarkers following significant trauma when compared with a 1:1:2 ratio. The development of post-traumatic ARDS, AKI, and death was associated with increased endothelial biomarker circulation.

LEVEL OF EVIDENCE

Therapeutic/Care Management; Level III.

Disseminated intravascular coagulation is strongly associated with severe acute kidney injury in patients with septic shock

BACKGROUND

Disseminated intravascular coagulation (DIC) worsens the prognosis of septic shock and contributes to multiple organ failure. To date, no data linking DIC and acute kidney injury (AKI) occurrence, severity, and evolution in this setting are available. We aimed at analyzing the association between AKI occurrence, severity and evolution in patients with septic shock-induced DIC. In a prospective monocentric cohort study, consecutive patients, 18 years and older, admitted in the ICU of Strasbourg University Hospital in the setting of systemic hypotension requiring vasopressor related to an infection, without history of terminal chronic kidney disease were eligible. AKI was defined according to the KDIGO classification. DIC diagnosis was based on the International Society on Thrombosis and Haemostasis (ISTH) score. Evolution of AKI was evaluated through the composite endpoint of major adverse kidney events. Only patients with DIC that occurred before or at the time of AKI diagnosis were considered. Univariate and multivariate analysis were performed to determine factors associated with renal outcomes.

RESULTS

350 patients were included, of whom 129 experienced DIC. Patients with DIC were more seriously ill (median SAPS II 64 vs. 56, p < 0.001), and had higher 28-day mortality (43.3% vs. 26.2%, p < 0.001). AKI was more frequent in patients with DIC (86.8% vs. 74.2%, p < 0.005), particularly for the more severe stage of AKI [KDIGO 3 in 58.1% of patients with DIC vs. 30.8% of patients without DIC, p < 0.001, AKI requiring renal replacement therapy (RRT) in 47.3% of patients with DIC vs. 21.3% of patients without DIC, p < 0.001]. After adjustment for confounding factors, DIC occurrence remained associated with the risk of having the more severe stage of AKI with an odds ratio (OR) of 2.74 [IC 95% (1.53-4.91), p < 0.001], and with the risk of requiring RRT during the ICU stay [OR 2.82 (1.53-5.2), p < 0.001].

CONCLUSION

DIC appears to be strongly associated with the risk of developing the more severe form of AKI (stage 3 of the KDIGO classification, RRT requirement), even after adjustment for severity and other relevant factors.

Prognostic value of APTT combined with fibrinogen and creatinine in predicting 28-Day mortality in patients with septic shock caused by acute enteric perforation

BACKGROUND

Septic shock is one of the leading causes of mortality in intensive care units. This retrospective study was carried out to evaluate the association of clinical available factors with 28-day mortality.

PATIENTS AND METHOD

In this observational study, patients with perioperative septic shocks secondary to intra-abdominal infection caused by enteric perforation were included. A total of 328 sepsis patients were admitted to the surgical intensive care units from January 2012 to December 2016. A total of 138 patients met the enrolment criteria and were included in the study. The data of demographic, clinical and laboratory were all recorded.

RESULT

All these 138 patients received abdominal surgery prior to surgical intensive care units caused by acute enteric perforation. These patients were all met the diagnostic criteria of septic shock according to Sepsis-3. Statistical analysis showed that lactic acid, blood platelet, fibrinogen, creatinine and activated partial thromboplastin time were found to be associated with 28-day mortality. A combination of serum activated partial thromboplastin time combined with fibrinogen and creatinine could predict in-hospital 28-day mortality. The area under the curve of serum activated partial thromboplastin time combined with fibrinogen and creatinine is 0.875 (0.806-0.944).

CONCLUSION

In conclusion, this pilot study demonstrated that these factors can predict the prognosis of septic shock caused by enteric perforation. In order to reduce the mortality, surgeons and intensive care units physician may consider these data in perioperative period.

Sepsis-associated acute kidney injury in the intensive care unit: incidence, patient characteristics, timing, trajectory, treatment, and associated outcomes. A multicenter, observational study

PURPOSE

The Acute Disease Quality Initiative (ADQI) Workgroup recently released a consensus definition of sepsis-associated acute kidney injury (SA-AKI), combining Sepsis-3 and Kidney Disease Improving Global Outcomes (KDIGO) AKI criteria. This study aims to describe the epidemiology of SA-AKI.

METHODS

This is a retrospective cohort study carried out in 12 intensive care units (ICUs) from 2015 to 2021. We studied the incidence, patient characteristics, timing, trajectory, treatment, and associated outcomes of SA-AKI based on the ADQI definition.

RESULTS

Out of 84,528 admissions, 13,451 met the SA-AKI criteria with its incidence peaking at 18% in 2021. SA-AKI patients were typically admitted from home via the emergency department (ED) with a median time to SA-AKI diagnosis of 1 day (interquartile range (IQR) 1-1) from ICU admission. At diagnosis, most SA-AKI patients (54%) had a stage 1 AKI, mostly due to the low urinary output (UO) criterion only (65%). Compared to diagnosis by creatinine alone, or by both UO and creatinine criteria, patients diagnosed by UO alone had lower renal replacement therapy (RRT) requirements (2.8% vs 18% vs 50%; p < 0.001), which was consistent across all stages of AKI. SA-AKI hospital mortality was 18% and SA-AKI was independently associated with increased mortality. In SA-AKI, diagnosis by low UO only, compared to creatinine alone or to both UO and creatinine criteria, carried an odds ratio of 0.34 (95% confidence interval (CI) 0.32-0.36) for mortality.

CONCLUSION

SA-AKI occurs in 1 in 6 ICU patients, is diagnosed on day 1 and carries significant morbidity and mortality risk with patients mostly admitted from home via the ED. However, most SA-AKI is stage 1 and mostly due to low UO, which carries much lower risk than diagnosis by other criteria.

Value of Serum Thrombomodulin as a Marker and Predictor in Patients with Sepsis-Associated Acute Kidney Injury

Objective

To investigate the serum soluble thrombomodulin (sTM) concentration in patients with sepsis-associated acute kidney injury (AKI) and to determine the value of sTM in predicting AKI and mortality in sepsis patients.

Methods

This prospective observational study was conducted on 71 patients diagnosed with sepsis according to Sepsis 3 at the Intensive Care Unit, Hue Central Hospital, Vietnam, from September 2021 to February 2023.

Results

Among 71 sepsis patients, there were 38 (53.5%) AKI cases, including 16 (22.5%) cases of stage 1 AKI, 14 (19.7%) cases of stage 2 AKI, 8 (11.3%) cases of stage 3 AKI, 16 (22.5%) cases of renal replacement therapy, 28 (39.4%) cases of septic shock, and 21 (29.6%) cases of mortality within 28 days. The concentrations of lactate and IL-6 in the AKI and mortality groups were statistically significantly greater than those in the non-AKI and survival groups (p < 0.05). The serum sTM concentration was 4.33 ng/mL, the serum sTM level in the AKI group was statistically significantly higher than that in the non-AKI group (sTM [4.71 vs 2.54 ng/mL, p < 0.001]), and the serum sTM level in the mortality group was statistically significantly higher than the survival group (sTM [4.78 vs 3.87 ng/mL, p < 0.001]). The AUC of sTM for predicting AKI was 0.864; the AUCs of sTM, IL-6, SOFA, and APACHE II for predicting mortality were 0.811, 0.671, 0.816, and 0.705, respectively.

Conclusion

AKI was a prevalent complication among sepsis patients at the ICU. In the AKI and mortality groups, sTM concentration was statistically significantly higher than that in the non-AKI and survival groups. sTM was the predictor of acute kidney injury and mortality in patients with sepsis.

Prognostic and predictive value of endothelial dysfunction biomarkers in sepsis-associated acute kidney injury: risk-stratified analysis from a prospective observational cohort of pediatric septic shock

BACKGROUND

Sepsis-associated acute kidney injury (SA-AKI) is associated with high morbidity, with no current therapies available beyond continuous renal replacement therapy (CRRT). Systemic inflammation and endothelial dysfunction are key drivers of SA-AKI. We sought to measure differences between endothelial dysfunction markers among children with and without SA-AKI, test whether this association varied across inflammatory biomarker-based risk strata, and develop prediction models to identify those at highest risk of SA-AKI.

METHODS

Secondary analyses of prospective observational cohort of pediatric septic shock. Primary outcome of interest was the presence of ≥ Stage II KDIGO SA-AKI on day 3 based on serum creatinine (D3 SA-AKI SCr). Biomarkers including those prospectively validated to predict pediatric sepsis mortality (PERSEVERE-II) were measured in Day 1 (D1) serum. Multivariable regression was used to test the independent association between endothelial markers and D3 SA-AKI SCr. We conducted risk-stratified analyses and developed prediction models using Classification and Regression Tree (CART), to estimate risk of D3 SA-AKI among prespecified subgroups based on PERSEVERE-II risk.

RESULTS

A total of 414 patients were included in the derivation cohort. Patients with D3 SA-AKI SCr had worse clinical outcomes including 28-day mortality and need for CRRT. Serum soluble thrombomodulin (sTM), Angiopoietin-2 (Angpt-2), and Tie-2 were independently associated with D3 SA-AKI SCr. Further, Tie-2 and Angpt-2/Tie-2 ratios were influenced by the interaction between D3 SA-AKI SCr and risk strata. Logistic regression demonstrated models predictive of D3 SA-AKI risk performed optimally among patients with high- or intermediate-PERSEVERE-II risk strata. A 6 terminal node CART model restricted to this subgroup of patients had an area under the receiver operating characteristic curve (AUROC) 0.90 and 0.77 upon tenfold cross-validation in the derivation cohort to distinguish those with and without D3 SA-AKI SCr and high specificity. The newly derived model performed modestly in a unique set of patients (n = 224), 84 of whom were deemed high- or intermediate-PERSEVERE-II risk, to distinguish those patients with high versus low risk of D3 SA-AKI SCr.

CONCLUSIONS

Endothelial dysfunction biomarkers are independently associated with risk of severe SA-AKI. Pending validation, incorporation of endothelial biomarkers may facilitate prognostic and predictive enrichment for selection of therapeutics in future clinical trials among critically ill children.

The clinical significance of renal resistance index (RRI) and renal oxygen saturation (RrSO2) in critically ill children with AKI: a prospective cohort study

OBJECTIVE

The purpose of this study was to look into the clinical significance of the renal resistance index (RRI) and renal oxygen saturation (RrSO2) in predicting the development of acute kidney injury (AKI) in critically ill children. A new non-invasive method for the early detection and prediction of AKI needs to develop.

METHODS

Patients admitted to the pediatric intensive care unit (PICU) affiliated with the capital institute of pediatrics from December 2020 to March 2021 were enrolled consecutively. Data of clinical information, renal Doppler ultrasound, RrSO2, and hemodynamic index within 24 h of admission were prospectively collected. Patients were divided into two groups: the study group was AKI occurred within 72 h, while the control group did not. SPSS (version 25.0) was used to analyze the data, and P < 0.05 was considered a statistical difference.

RESULTS

1) A total of 66 patients were included in this study, and the incidence of AKI was 19.70% (13/66). The presence of risk factors (shock, tumor, severe infection) increased the incidence of AKI by three times. 2) Univariate analysis showed significant differences in length of hospitalization, white blood cells (WBC), C-reactive protein (CRP), renal resistance index (RRI), and ejection fraction (EF) between the study and control groups (P < 0.05). There were no significant differences in renal perfusion semi-quantitative score (P = 0.053), pulsatility index (P = 0.051), pediatric critical illness score (PCIS), and peripheral vascular resistance index (P > 0.05). 3) Receiver operating characteristic (ROC) curve showed that if RRI > 0.635, the sensitivity, specificity, and AUC for predicting AKI were 0.889, 0.552, and 0.751, respectively; if RrSO2 < 43.95%, the values were 0.615, 0.719 and 0.609, respectively; if RRI and RrSO2 were united, they were 0.889, 0.552, and 0.766, respectively.

CONCLUSIONS

The incidence of AKI is high in PICU patients. And infection, RRI, and EF are risk factors for AKI in PICU patients. RRI and RrSO2 have certain clinical significance in the early prediction of AKI and may provide a new non-invasive method for early diagnosis and prediction of AKI.

Endothelial dysfunction and immunothrombosis in sepsis

Sepsis is a life-threatening clinical syndrome characterized by multiorgan dysfunction caused by a dysregulated or over-reactive host response to infection. During sepsis, the coagulation cascade is triggered by activated cells of the innate immune system, such as neutrophils and monocytes, resulting in clot formation mainly in the microcirculation, a process known as immunothrombosis. Although this process aims to protect the host through inhibition of the pathogen’s dissemination and survival, endothelial dysfunction and microthrombotic complications can rapidly lead to multiple organ dysfunction. The development of treatments targeting endothelial innate immune responses and immunothrombosis could be of great significance for reducing morbidity and mortality in patients with sepsis. Medications modifying cell-specific immune responses or inhibiting platelet–endothelial interaction or platelet activation have been proposed. Herein, we discuss the underlying mechanisms of organ-specific endothelial dysfunction and immunothrombosis in sepsis and its complications, while highlighting the recent advances in the development of new therapeutic approaches aiming at improving the short- or long-term prognosis in sepsis.

The study on role of endothelial cell autophagy in rats with sepsis-induced acute kidney injury

Sepsis often causes acute kidney injury (AKI). Autophagy of renal tubular epithelial cells is considered a cytoprotective mechanism in septic AKI; however, the role of autophagy of renal endothelial cells is uninvestigated. The current study examined whether autophagy was induced by sepsis in renal endothelial cells and whether induction of autophagy in these cells attenuated the degree of AKI. Cecal ligation and puncture (CLP) was used as a model of sepsis in rats. Four experimental groups included: sham, CLP alone, CLP + rapamycin (RAPA), and CLP + dimethyl sulfoxide (DMSO), where RAPA was used as an activator of autophagy. CLP increased renal LC3-II protein levels with an additional transient increase by RAPA at 18 h. In addition, CLP induced autophagosome formation in renal endothelial cells had an additional increase induced by RAPA. Interestingly, the levels of bone morphogenetic protein and activin membrane-bound inhibitor (BAMBI), an endothelial cell-specific protein in the kidney, were also increased by CLP, albeit it was transiently downregulated by RAPA at 18 h. Serum thrombomodulin increased and renal vascular endothelial (VE)-cadherin decreased following CLP, and these changes were attenuated by RAPA. The renal cortex exhibited and inflammatory tissue damage after CLP, and RAPA alleviated these histopathological injuries. The current findings indicate that autophagy was induced by sepsis in renal endothelial cells, and upregulation of autophagy in these cells alleviated endothelial injury and AKI. In addition, BAMBI was induced by sepsis in the kidney, which may play a role in regulating endothelial stability in septic AKI.

Definitions, phenotypes, and subphenotypes in acute kidney injury-Moving towards precision medicine

The current definition of acute kidney injury (AKI) is generic and, based only on markers of function, is unsuitable for guiding individualized treatment. AKI is a complex syndrome with multiple presentations and causes. Targeted AKI management will only be possible if different phenotypes and subphenotypes of AKI are recognised, based on causation and related pathophysiology. Molecular signatures to identify subphenotypes are being recognised, as specific biomarkers reveal activated pathways. Assessment of individual clinical risk needs wider dissemination to allow identification of patients at high risk of AKI. New and more timely markers for glomerular filtration rate (GFR) are available. However, AKI diagnosis and classification should not be limited to GFR, but include tubular function and damage. Combining damage and stress biomarkers with functional markers enhances risk prediction, and identifies a population enriched for clinical trials targeting AKI. We review novel developments and aim to encourage implementation of these new techniques into clinical practice as a strategy for individualizing AKI treatment akin to a precision medicine-based approach.

Serum Thrombomodulin Level Can Predict Mortality in Patients With Sepsis?

Background

Thrombomodulin (TM) is a type-1 trans-membrane glycoprotein on endothelial cells which is known to be involved in various biochemical pathways. TM can be detected in biological fluids such as blood and urine under many forms. Soluble thrombomodulin (sTM), consist of various particles of TM, is the predominant agent which is created by enzymatic or chemical catalysis of the whole protein under divergent conditions. TM plays a vital role in protein C system and is crucial in the pathogenesis of Sepsis.

Objective

To identify the serum level of soluble thrombomodulin (sTM) in groups of patients: sepsis and septic shock including their survival and fatal in-hospital outcome; and validate the death prediction of serum sTM in patients with sepsis.

Methods

This prospective observational study was conducted in 63 patients who were diagnosed with sepsis, septic shock according to Sepsis 3 criteria at the ICU Department of Hue Central Hospital, Vietnam, from 3/2022 to 3/2023.

Results

Twenty participants developed septic shock (31.7%), morality within 28-days was 19 patients (30.2%), 22 patients complicated with acute kidney injury that necessitated renal replacement therapy (34.9%), 30 patients required mechanical ventilation (47.6%), the median length of ICU stay was 8 (3-28) days. Serum level of lactate and creatinine were significantly higher in septic shock group compared with sepsis and survival group (p<0.05). The median sTM level in septic shock group and fatal group were 4.68(3.38-6.46) ng/mL and 4.68 (1.69-6.46) ng/mL, respectively. These results were significantly higher than sepsis group [3.62 (1.51-1.94) ng/mL] and survival group [3.73 (1.51-5.9) ng/mL] (p<0.05). The death predictive power of DIC score, APACHE II score, creatinine, sTM and SOFA presented with AUC values of 0.723, 0.726, 0.777, 0.803 and 0.807, respectively. There were no significant difference of serum level IL-6 and PCT between survival and fatal group. The median DIC score in fatal group was 7 (3-7), which was significantly higher than survival group 4 (2-7) (p= 0.001).

Conclusion

Sepsis is a common diagnosis among ICU settings which links the critically ill patients to higher complications and mortalities. Serum level of sTM in septic shock and fatal groups were significantly higher than sepsis and survival groups. sTM is a reliable marker and should be used in predict severity and mortality in sepsis patients.

Comparison of diagnostic criteria for acute kidney injury in critically ill children: a multicenter cohort study

Background

Substantial interstudy heterogeneity exists in defining acute kidney injury (AKI) and baseline serum creatinine (SCr). This study assessed AKI incidence and its association with pediatric intensive care unit (PICU) mortality under different AKI and baseline SCr definitions to determine the preferable approach for diagnosing pediatric AKI.

Methods

In this multicenter prospective observational cohort study, AKI was defined and staged according to the Kidney Disease: Improving Global Outcome (KDIGO), modified KDIGO, and pediatric reference change value optimized for AKI (pROCK) definitions. The baseline SCr was calculated based on the Schwartz formula or estimated as the upper normative value (NormsMax), admission SCr (AdmSCr) and modified AdmSCr. The impacts of different AKI definitions and baseline SCr estimation methods on AKI incidence, severity distribution and AKI outcome were evaluated.

Results

Different AKI definitions and baseline SCr estimates led to differences in AKI incidence, from 6.8 to 25.7%; patients with AKI across all definitions had higher PICU mortality ranged from 19.0 to 35.4%. A higher AKI incidence (25.7%) but lower mortality (19.0%) was observed based on the Schwartz according to the KDIGO definition, which however was overcome by modified KDIGO (AKI incidence: 16.3%, PICU mortality: 26.1%). Furthermore, for the modified KDIGO, the consistencies of AKI stages between different baseline SCr estimation methods were all strong with the concordance rates > 90.0% and weighted kappa values > 0.8, and PICU mortality increased pursuant to staging based on the Schwartz. When the NormsMax was used, the KDIGO and modified KDIGO led to an identical AKI incidence (13.6%), but PICU mortality did not differ among AKI stages. For the pROCK, PICU mortality did not increase pursuant to staging and AKI stage 3 was not associated with mortality after adjustment for confounders.

Conclusions

The AKI incidence and staging vary depending on the definition and baseline SCr estimation method used. The modified KDIGO definition based on the Schwartz method leads AKI to be highly relevant to PICU mortality, suggesting that it may be the preferable approach for diagnosing AKI in critically ill children and provides promise for improving clinicians’ ability to diagnose pediatric AKI.

Plasma proteomic characterization of the development of acute kidney injury in early sepsis patients

Acute kidney injury (AKI) develops frequently in the course of patients with sepsis and strongly associates with in-hospital mortality. However, diagnosing AKI involves a considerable lag-time because it depends on assessing an increase in serum creatinine, and offers no insight in the underlying pathophysiology. Consequently, identifying a set of proteins reflecting the development of AKI may improve earlier recognition of AKI and the understanding of its pathophysiology. A targeted plasma proteomic approach was performed in early sepsis patients with and without subsequent AKI development in a matched pair design (n = 19 each). Principal component analysis identified 53 proteins associated with development of AKI, which were further analysed using Enrichr gene ontology and pathway analysis. Nine differentially expressed proteins from the targeted proteomics were increased among patients who subsequently developed AKI and correlated with principal components, namely CALCA, CALR, CA12, CLEC1A, PTK7, KIM-1, NPPC, NUCB2 and PGF. We demonstrated the biological insight in the development of AKI in early sepsis compared to non-AKI sepsis.

High plasma soluble thrombomodulin levels indicated poor prognosis of decompensated liver cirrhosis: a prospective cohort study

OBJECTIVE

Hepatic sinusoidal endothelial injury is a prominent characteristic of liver cirrhosis. We determined plasma soluble thrombomodulin (sTM) levels in cirrhosis patients to evaluate the relationship between vascular injury and long-term prognosis.

METHODS

A prospective single-center study was performed. The participants were followed up for every 6 months or until death or transplantation. A chemiluminescent enzyme immunoassay was used to establish a baseline sTM.

RESULTS

Among the 219 patients with decompensated liver cirrhosis, 53.42% were caused by hepatitis B and hepatitis C. Plasma sTM levels were much higher in cirrhosis than in healthy controls and increased parallel with Child-Pugh classification ( P &lt; 0.01) and the amount of ascites ( P = 0.04). After adjusting for sex, age, international normalized ratio, bilirubin, and other potential factors, multivariate Cox regression revealed that per TU/ml elevation of plasma sTM causes an increase of 8% in mortality, and per-SD elevation of thrombomodulin causes a 53% increase in mortality. As the mortality rates in low (5.90-12.60 TU/ml) and medium (12.70-18.00 TU/ml) sTM levels were similar, so we chose the cutoff of 18.00 TU/ml to divide into two groups, and K-M analysis indicated that patients with sTM &gt;18.0 TU/ml demonstrated an additional 2.01 times death risk (95% CI, 1.13-7.93; P = 0.01) than those with sTM ≤18.0 TU/ml.

CONCLUSION

Plasma sTM in cirrhosis was significantly increased in parallel with the severity of liver dysfunction. sTM elevation than 18 TU/ml indicated a poor prognosis of decompensated liver cirrhosis.

Acute kidney injury in group A streptococcal bacteraemia: incidence, outcome and predictive value of C-reactive protein

BACKGROUND

A ubiquitous human pathogen, Streptococcus pyogenes (Group A Streptococcus, GAS) causes infections from mild pharyngitis to severe septic infections. Acute kidney injury (AKI) is a condition of prompt decline of renal function. The aim of the present study was to report the incidence and outcome of AKI in GAS bacteraemia and to evaluate the diagnostic value of serum C-reactive protein as an indicator of AKI.

METHODS

All adult patients with GAS bacteraemia treated at Turku University Hospital from 2007 to 2018 were identified and their patient records were scrutinised.

RESULTS

Of 195 included patients, 38 (19.5%) had AKI stage 1, 20 (10.3%) AKI stage 2 and 26 (13.3%) AKI stage 3 and 111 (56.9%) did not have AKI. The adjusted seven-day mortality was significantly higher in AKI stages 2 and 3 compared to the non-AKI group (15% and 19% vs. 3.6%; p = .046 and .006, respectively). Of the survivors, 95.8% met the criteria of renal recovery at discharge. The higher the AKI stage, the higher was the mean serum CRP level on admission. The optimal cut-off for CRP to identify patients with AKI stage 2 or 3 was ≥244 mg/l (sensitivity 82.6% and specificity 75.8%).

CONCLUSIONS

AKI is common in patients with GAS bacteraemia and the severity of AKI correlates with the CRP level on admission. The mortality of patients with GAS bacteraemia and AKI is significantly higher than of patients without AKI. Most survivors, however, show renal recovery.Key MessageAKI is common in group A Streptococcal bacteraemia and increases mortality compared to bacteraemia alone. However, renal recovery is also common. A high CRP level on admission correlates significantly positively with the degree of severity of AKI.

Multi-Omics Techniques Make it Possible to Analyze Sepsis-Associated Acute Kidney Injury Comprehensively

Sepsis-associated acute kidney injury (SA-AKI) is a common complication in critically ill patients with high morbidity and mortality. SA-AKI varies considerably in disease presentation, progression, and response to treatment, highlighting the heterogeneity of the underlying biological mechanisms. In this review, we briefly describe the pathophysiology of SA-AKI, biomarkers, reference databases, and available omics techniques. Advances in omics technology allow for comprehensive analysis of SA-AKI, and the integration of multiple omics provides an opportunity to understand the information flow behind the disease. These approaches will drive a shift in current paradigms for the prevention, diagnosis, and staging and provide the renal community with significant advances in precision medicine in SA-AKI analysis.

Circulating Thrombomodulin: Release Mechanisms, Measurements, and Levels in Diseases and Medical Procedures

Thrombomodulin (TM) is a type-I transmembrane protein that is mainly expressed on endothelial cells and plays important roles in many biological processes. Circulating TM of different forms are also present in biofluids, such as blood and urine. Soluble TM (sTM), comprised of several domains of TM, is the major circulating TM which is generated by either enzymatic or chemical cleavage of the intact protein under different conditions. Under normal conditions, sTM is present in low concentrations (<10 ng/mL) in the blood but is elevated in several pathological conditions associated with endothelial dysfunction such as cardiovascular, inflammatory, infection, and metabolic diseases. Therefore, sTM level has been examined for monitoring disease development, such as disseminated intravascular coagulation (DIC), sepsis and multiple organ dysfunction syndrome in patients with novel coronavirus disease 2019 (COVID-19) recently. In addition, microvesicles (MVs) that contain membrane TM (MV-TM) have been found to be released from activated cells which also contribute to levels of circulating TM in certain diseases. Several release mechanisms of sTM and MV-TM have been reported, including enzymatic, chemical, and TM mutation mechanisms. Measurements of sTM and MV-TM have been developed and explored as biomarkers in many diseases. In this review, we summarize all these advances in three categories as follows: (1) release mechanisms of circulating TM, (2) methods for measuring circulating TM in biological samples, and (3) correlation of circulating TM with diseases. Altogether, it provides a whole picture of recent advances on circulating TM in health and disease.

Clinical Value of Prognostic Nutritional Index and Neutrophil-to-Lymphocyte Ratio in Prediction of the Development of Sepsis-Induced Kidney Injury

Background

Sepsis-related acute kidney injury (S-AKI) is a frequent complication of hospitalized patients and is linked to increased morbidity and mortality. Early prediction and detection remain conducive to optimizing treatment strategies and limiting further insults. This study was aimed at evaluating the potential predictive value of the combined prognostic nutrition index (PNI) and neutrophil-to-lymphocyte ratio (NLR) to predict the risk of AKI in septic patients.

Methods

In this retrospective study, 1238 adult patients with sepsis who were admitted to the First Affiliated Hospital of Xi'an Jiaotong University from January 2015 to June 2021 were enrolled. Patients were divided into two groups: the non-AKI group (n = 731) and the S-AKI group (n = 507). Univariate and multivariate logistic regression analyses were performed to screen the independent predictive factors of S-AKI. A receiver operating characteristic (ROC) curve was used to evaluate the predictive value of PNI and NLR.

Results

Multivariate logistic regression analysis indicated that age, chronic liver disease, cardiovascular disease, respiratory rate (RR), white blood cells (WBC), blood urea nitrogen (BUN), creatinine (CRE), international normalized ratio (INR), neutrophil-to-lymphocyte ratio (NLR), and prognostic nutrition index (PNI) were independent prognostic factors of S-AKI. In the three models, the adjusted OR of PNI for S-AKI was 0.802 (0.776-0.829), 0.801 (0.775-0.829), and 0.717 (0.666-0.772), while that of NLR was 1.094 (1.078-1.111), 1.097 (1.080-1.114), and 1.044 (1.016-1.072), respectively. In addition, the area under the ROC curve of the PNI plus NLR group was significantly greater than that of the CRE plus BUN group (0.801, 95% CI: 0.775-0.827 vs. 0.750, 95% CI: 0.722-0.778, respectively; P < 0.001).

Conclusions

PNI and NLR have been identified as readily available and independent predictors in septic patients with S-AKI. PNI, in combination with NLR, is of vital significance for early warning and efficient intervention of S-AKI and is superior to combined BUN and CRE.

Machine learning for the prediction of acute kidney injury in patients with sepsis

BACKGROUND

Acute kidney injury (AKI) is the most common and serious complication of sepsis, accompanied by high mortality and disease burden. The early prediction of AKI is critical for timely intervention and ultimately improves prognosis. This study aims to establish and validate predictive models based on novel machine learning (ML) algorithms for AKI in critically ill patients with sepsis.

METHODS

Data of patients with sepsis were extracted from the Medical Information Mart for Intensive Care III (MIMIC- III) database. Feature selection was performed using a Boruta algorithm. ML algorithms such as logistic regression (LR), k-nearest neighbors (KNN), support vector machine (SVM), decision tree, random forest, Extreme Gradient Boosting (XGBoost), and artificial neural network (ANN) were applied for model construction by utilizing tenfold cross-validation. The performances of these models were assessed in terms of discrimination, calibration, and clinical application. Moreover, the discrimination of ML-based models was compared with those of Sequential Organ Failure Assessment (SOFA) and the customized Simplified Acute Physiology Score (SAPS) II model.

RESULTS

A total of 3176 critically ill patients with sepsis were included for analysis, of which 2397 cases (75.5%) developed AKI during hospitalization. A total of 36 variables were selected for model construction. The models of LR, KNN, SVM, decision tree, random forest, ANN, XGBoost, SOFA and SAPS II score were established and obtained area under the receiver operating characteristic curves of 0.7365, 0.6637, 0.7353, 0.7492, 0.7787, 0.7547, 0.821, 0.6457 and 0.7015, respectively. The XGBoost model had the best predictive performance in terms of discrimination, calibration, and clinical application among all models.

CONCLUSION

The ML models can be reliable tools for predicting AKI in septic patients. The XGBoost model has the best predictive performance, which can be used to assist clinicians in identifying high-risk patients and implementing early interventions to reduce mortality.

Biomarkers Predicting Tissue Pharmacokinetics of Antimicrobials in Sepsis: A Review

The pathophysiology of sepsis alters drug pharmacokinetics, resulting in inadequate drug exposure and target-site concentration. Suboptimal exposure leads to treatment failure and the development of antimicrobial resistance. Therefore, we seek to optimize antimicrobial therapy in sepsis by selecting the right drug and the correct dosage. A prerequisite for achieving this goal is characterization and understanding of the mechanisms of pharmacokinetic alterations. However, most infections take place not in blood but in different body compartments. Since tissue pharmacokinetic assessment is not feasible in daily practice, we need to tailor antibiotic treatment according to the specific patient’s pathophysiological processes. The complex pathophysiology of sepsis and the ineffectiveness of current targeted therapies suggest that treatments guided by biomarkers predicting target-site concentration could provide a new therapeutic strategy. Inflammation, endothelial and coagulation activation markers, and blood flow parameters might be indicators of impaired tissue distribution. Moreover, hepatic and renal dysfunction biomarkers can predict not only drug metabolism and clearance but also drug distribution. Identification of the right biomarkers can direct drug dosing and provide timely feedback on its effectiveness. Therefore, this might decrease antibiotic resistance and the mortality of critically ill patients. This article fills the literature gap by characterizing patient biomarkers that might be used to predict unbound plasma-to-tissue drug distribution in critically ill patients. Although all biomarkers must be clinically evaluated with the ultimate goal of combining them in a clinically feasible scoring system, we support the concept that the appropriate biomarkers could be used to direct targeted antibiotic dosing.

Commonly expressed key transcriptomic profiles of sepsis in the human circulation and brain via integrated analysis

BACKGROUND

Sepsis is the leading cause of death in intensive care units and is characterized by multiple organ failure, including dysfuction of the immune system and brain. This study aims to determine the differential effect of sepsis on specific circulating immune cell subsets compared with brain transcriptome and identify the genes co-expressed by them, so as to identify key genes and regulatory factors involved in the pathogenesis of sepsis induced brain injury and identify novel therapeutic targets.

METHODS

The GSE133822 and GSE135838 datasets were obtained from the Gene Expression Omnibus (GEO) database and utilized for bioinformatics analyses. Functional enrichment analysis was used to identify commonly expressed genes that were differentially expressed between sepsis patients and non-sepsis patients with critical illness; protein-protein interaction (PPI) networks were also generated. Then, key transcriptomic biomarkers were further validated in an external dataset from the GEO. We also investigated the expression of key mRNAs in peripheral blood mononuclear cells (PBMCs) from sepsis patients by quantitative PCR (qPCR) and an in-vitro model stimulated by lipopolysaccharide (LPS) was generated in brain cell lines.

RESULTS

The transcriptomic profiles of brain tissue were relatively similar as those of specific immune cells. In addition, our validation showed that these key genes were up regulated both in PBMCs in sepsis patients and LPS-treated brain cells.

CONCLUSION

Brain injury in sepsis was correlated with circulating immune responses, and the expression of DEFA3, MMP8, MMP9 and LCN2 might be potential diagnostic biomarkers as well as therapeutic target in septic brain dysfunction.

Machine learning for early discrimination between transient and persistent acute kidney injury in critically ill patients with sepsis

Acute kidney injury (AKI) is commonly present in critically ill patients with sepsis. Early prediction of short-term reversibility of AKI is beneficial to risk stratification and clinical treatment decision. The study sought to use machine learning methods to discriminate between transient and persistent sepsis-associated AKI. Septic patients who developed AKI within the first 48 h after ICU admission were identified from the Medical Information Mart for Intensive Care III database. AKI was classified as transient or persistent according to the Acute Disease Quality Initiative workgroup consensus. Five prediction models using logistic regression, random forest, support vector machine, artificial neural network and extreme gradient boosting were constructed, and their performance was evaluated by out-of-sample testing. A simplified risk prediction model was also derived based on logistic regression and features selected by machine learning algorithms. A total of 5984 septic patients with AKI were included, 3805 (63.6%) of whom developed persistent AKI. The artificial neural network and logistic regression models achieved the highest area under the receiver operating characteristic curve (AUC) among the five machine learning models (0.76, 95% confidence interval [CI] 0.74-0.78). The simplified 14-variable model showed adequate discrimination, with the AUC being 0.76 (95% CI 0.73-0.78). At the optimal cutoff of 0.63, the sensitivity and specificity of the simplified model were 63% and 76% respectively. In conclusion, a machine learning-based simplified prediction model including routine clinical variables could be used to differentiate between transient and persistent AKI in critically ill septic patients. An easy-to-use risk calculator can promote its widespread application in daily clinical practice.

Protective Role of Recombinant Human Thrombomodulin in Diabetes Mellitus

Diabetes mellitus is a global threat to human health. The ultimate cause of diabetes mellitus is insufficient insulin production and secretion associated with reduced pancreatic β-cell mass. Apoptosis is an important and well-recognized mechanism of the progressive loss of functional β-cells. However, there are currently no available antiapoptotic drugs for diabetes mellitus. This study evaluated whether recombinant human thrombomodulin can inhibit β-cell apoptosis and improve glucose intolerance in a diabetes mouse model. A streptozotocin-induced diabetes mouse model was prepared and treated with thrombomodulin or saline three times per week for eight weeks. The glucose tolerance and apoptosis of β-cells were evaluated. Diabetic mice treated with recombinant human thrombomodulin showed significantly improved glucose tolerance, increased insulin secretion, decreased pancreatic islet areas of apoptotic β-cells, and enhanced proportion of regulatory T cells and tolerogenic dendritic cells in the spleen compared to counterpart diseased mice treated with saline. Non-diabetic mice showed no changes. This study shows that recombinant human thrombomodulin, a drug currently used to treat patients with coagulopathy in Japan, ameliorates glucose intolerance by protecting pancreatic islet β-cells from apoptosis and modulating the immune response in diabetic mice. This observation points to recombinant human thrombomodulin as a promising antiapoptotic drug for diabetes mellitus.

Adipose-Derived Inflammatory and Coagulant Mediators in Patients With Sepsis

ABSTRACT

Results from preclinical sepsis studies using rodents are often criticized as not being reproducible in humans. Using a murine model, we previously reported that visceral adipose tissues (VAT) are highly active during the acute inflammatory response, serving as a major source of inflammatory and coagulant mediators. The purpose of this study was to determine whether these findings are recapitulated in patients with sepsis and to evaluate their clinical significance. VAT and plasma were obtained from patients undergoing intra-abdominal operations with noninflammatory conditions (control), local inflammation, or sepsis. In mesenteric and epiploic VAT, gene expression of pro-inflammatory (TNFα, IL-6, IL-1α, IL-1β) and pro-coagulant (PAI-1, PAI-2, TSP-1, TF) mediators was increased in sepsis compared with control and local inflammation groups. In the omentum, increased expression was limited to IL-1β, PAI-1, and PAI-2, showing a depot-specific regulation. Histological analyses showed little correlation between cellular infiltration and gene expression, indicating a resident source of these mediators. Notably, a strong correlation between PAI-1 expression in VAT and circulating protein levels was observed, both being positively associated with markers of acute kidney injury (AKI). In another cohort of septic patients stratified by incidence of AKI, circulating PAI-1 levels were higher in those with versus without AKI, thus extending these findings beyond intra-abdominal cases. This study is the first to translate upregulation of VAT mediators in sepsis from mouse to human. Collectively, the data suggest that development of AKI in septic patients is associated with high plasma levels of PAI-1, likely derived from resident cells within VAT.

Recalibration of the Renal Angina Index for Pediatric Septic Shock

Introduction

Sepsis-associated acute kidney injury (AKI) is a common diagnosis in children that is associated with poor outcomes. The lack of therapeutic options once present makes early identification of at-risk patients essential. The renal angina index (RAI) has been previously validated to predict severe AKI in heterogeneous populations of critically ill children. The performance of this score specifically in children with septic shock is unknown.

Methods

A secondary analysis of a multicenter, prospective, observational study of 379 children with septic shock to determine the ability of the RAI to predict severe AKI at day 3, and to assess for the potential need for recalibration of the RAI in this unique subset of patients.

Results

At the original cutoff of ≥8, the RAI predicted day 3 severe AKI with an area under the receiving operating characteristic (AUROC) curve 0.90 (95% confidence interval [CI]: 0.86 to 93), 95% sensitivity, and 54% specificity. A Youden's index identified a higher optimal cutoff of ≥20 (sensitivity 83%, specificity 80%), and day 1 platelet count <150 × 10³/μl was an independent predictor of severe AKI (adjusted odds ratio: 3.2; 95% CI: 1.7 to 6.3; P < 0.001). Recalibration of the RAI to include platelet count and this new threshold restored the sensitivity of the original ≥8 threshold (95%), while improving its specificity (69%).

Conclusions

The RAI appears to be a sensitive and reliable tool for prediction of severe AKI in children with septic shock, although the use of a recalibrated sepsis-specific RAI using a higher cutoff and platelet count may be beneficial.

Fibrinolytic Alterations in Sepsis: Biomarkers and Future Treatment Targets

Sepsis is a life-threatening condition which develops as a dysregulated immune response in the face of infection and which is associated with profound hemostatic disturbances and in the most extreme cases disseminated intravascular coagulation (DIC). In addition, the fibrinolytic system is subject to alterations during infection and sepsis, and impaired fibrinolysis is currently considered a key player in sepsis-related microthrombus formation and DIC. However, we still lack reliable biomarkers to assess fibrinolysis in the clinical setting. Furthermore, drugs targeting the fibrinolytic system have potential value in sepsis patients with severe fibrinolytic disturbances, but these are still being tested in the preclinical stage. The present review provides an overview of key fibrinolytic changes in sepsis, reviews the current literature on potential laboratory markers of altered fibrinolysis in adult sepsis patients, and discusses future perspectives for diagnosis and treatment of fibrinolytic disturbances in sepsis patients.

Unraveling the epigenetic landscape of glomerular cells in kidney disease

Chronic kidney disease (CKD) is a major public health concern and its prevalence and incidence are rising quickly. It is a non-communicable disease primarily caused by diabetes and/or hypertension and is associated with high morbidity and mortality. Despite decades of research efforts, the pathogenesis of CKD remains a puzzle with missing pieces. Understanding the cellular and molecular mechanisms that govern the loss of kidney function is crucial. Abrupt regulation of gene expression in kidney cells is apparent in CKD and shown to be responsible for disease onset and progression. Gene expression regulation extends beyond DNA sequence and involves epigenetic mechanisms including changes in DNA methylation and post-translational modifications of histones, driven by the activity of specific enzymes. Recent advances demonstrate the essential participation of epigenetics in kidney (patho)physiology, as its actions regulate both the integrity of cells but also triggers deleterious signaling pathways. Here, we review the known epigenetic processes regulating the complex filtration unit of the kidney, the glomeruli. The review will elaborate on novel insights into how epigenetics contributes to cell injury in the CKD setting majorly focusing on kidney glomerular cells: the glomerular endothelial cells, the mesangial cells, and the specialized and terminally differentiated podocyte cells.

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.

Rates, predictors, and mortality of sepsis-associated acute kidney injury: a systematic review and meta-analysis

BACKGROUND

Due to the high incidence and mortality of sepsis-associated acute kidney injury, a significant number of studies have explored the causes of sepsis-associated acute kidney injury (AKI). However, the opinions on relevant predictive risk factors remain inconclusive. This study aimed to provide a systematic review and meta-analysis to determine the predisposing factors for sepsis-associated AKI.

METHOD

A systematic literature search was performed in the Medline, Embase, Cochrane Library, PubMed, and Web of Science, databases, with an end-date of 25th May 2019. Valid data were retrieved in compliance with specific inclusion and exclusion criteria.

RESULT

Forty-seven observational studies were included for analysis, achieving a cumulative patient number of 55,911. The highest incidence of AKI was caused by septic shock. Thirty-one potential risk factors were included in the meta-analysis. Analysis showed that 20 factors were statistically significant. The odds ratio (OR) and 95% confidence interval (CI), as well as the prevalence of the most frequently-seen predisposing factors for sepsis-associated AKI, were as follows: septic shock [2.88 (2.36-3.52), 60.47%], hypertension [1.43 (1.20-1.70), 38.39%], diabetes mellitus [1.59 (1.47-1.71), 27.57%], abdominal infection [1.44 (1.32-1.58), 30.87%], the administration of vasopressors [2.95 (1.67-5.22), 64.61%], the administration of vasoactive drugs [3.85 (1.89-7.87), 63.22%], mechanical ventilation [1.64 (1.24-2.16), 68.00%], positive results from blood culture [1.60 (1.35-1.89), 41.19%], and a history of smoking [1.60 (1.09-2.36), 43.09%]. Other risk factors included cardiovascular diseases, coronary artery diseases, liver diseases, unknown infections, the administration of diuretics and ACEI/ARB, the infection caused by gram-negative bacteria, and organ transplantation.

CONCLUSION

Risk factors of S-AKI arise from a wide range of sources, making it difficult to predict and prevent this condition. Comorbidities, and certain drugs, are the main risk factors for S-AKI. Our review can provide guidance on the application of interventions to reduce the risks associated with sepsis-associated acute kidney injury and can also be used to tailor patient-specific treatment plans and management strategies in clinical practice.

Delta Neutrophil Index for the Prediction of the Development of Sepsis-Induced Acute Kidney Injury in the Emergency Department

BACKGROUND AND PURPOSE

The early prediction of acute kidney injury (AKI) in sepsis and provision of timely treatment may improve outcomes. We investigated the efficacy of the delta neutrophil index (DNI)-which reflects the fraction of immature granulocytes-in predicting sepsis-induced AKI and 30-day mortality in cases of severe sepsis or septic shock.

METHODS

This retrospective, observational cohort study was performed with patients prospectively integrated in a critical pathway of early-goal-directed therapy /SEPSIS. We analyzed adult sepsis patients admitted to the emergency department with normal kidney function or stage 1 disease, based on the Acute Kidney Injury Network classification, between January 1, 2014 and September 30, 2017. The outcomes were the development of sepsis-induced severe AKI within 7 days and 30-day mortality.

RESULTS

A total of 346 patients were enrolled. An increase in the DNI values at Time-0 (odds ratio [OR], 1.060; P < 0.001) and Time-12 (OR, 1.086; P < 0.001) were strong independent predictors of severe AKI development. The increasing predictability of AKI was closely associated with a DNI ≥14.0% at Time-0 (OR, 7.238; P < 0.001) and ≥13.3% at Time-12 (OR, 18.089; P < 0.001). The development of severe AKI was an independent predictor of 30-day mortality (hazard ratio: 25.2, P < 0.001).

CONCLUSION

Higher DNI values are independent predictors of severe AKI development and 30-day mortality in sepsis. Physicians can use the DNI to quickly determine the severity of sepsis and initial treatment strategies without additional costs and effort.

miR-331 inhibits CLDN2 expression and may alleviate the vascular endothelial injury induced by sepsis

The present study aimed to determine the expression level of claudin-2 (CLDN2) in the peripheral blood of patients with sepsis, and to investigate its potential function and mechanism of action in vascular endothelial injury. A total of 25 patients with sepsis were included in the present study. Reverse transcription-quantitative PCR was used to determine CLDN2 levels in peripheral blood. HUVECs stably expressing CLDN2 were prepared and Cell Counting Kit-8, flow cytometry and Transwell assays were performed to study the proliferation, apoptosis and migration of HUVECs, respectively. Using bioinformatics, microRNA (miR) molecules that interact with CLDN2 were predicted. A dual luciferase reporter assay was used to test whether miR-331 regulated CLDN2. Western blotting was employed to determine CLDN2 protein expression. In addition, in vitro transfection of HUVECs with miR-331 mimics was performed to test the rescue effects of miR-331 on the cell function changes induced by CLDN2. The results indicated that elevated CLDN2 expression altered the proliferation and cell cycle of peripheral vascular endothelial cells. CLDN2 overexpression inhibited HUVEC proliferation via mechanisms not associated with the cell cycle. CLDN2 mRNA levels in the peripheral blood of patients with sepsis were significantly higher than those in healthy subjects. Upregulated CLDN2 expression promoted the apoptosis of HUVECs, but reduced their proliferation and migration. Notably, miR-331 was able to bind with CLDN2 mRNA and regulate its expression. Upregulation of miR-331 expression inhibited the expression of CLDN2 and restored nearly normal proliferation, apoptosis and migration to HUVECs. The present study demonstrated that CLDN2 expression is elevated in peripheral blood from patients with sepsis, and promotes the injury of vascular endothelial cells. In addition, miR-331 participates in the direct regulation of CLDN2, and upregulation of miR-331 expression inhibits the expression of CLDN2 and restores cellular functions to HUVECs.

Preoperative Serum Fibrinogen is Associated With Acute Kidney Injury after Cardiac Valve Replacement Surgery

Acute kidney injury (AKI) after open cardiac surgery is associated with a longer hospital stay and higher risk of mortality. We aimed to explore the association between preoperative serum fibrinogen level and risk of postoperative AKI in patients with open cardiac surgery. 3459 patients who underwent cardiac valve replacement surgery from January 2011 to September 2015 were recruited. The primary outcome was AKI, defined as AKI stage-1 or higher based on the Kidney Disease: Improving Global Outcomes (KDIGO) Guidelines. Synthetic Minority Oversampling Technique (SMOTE) was used to subsample minority groups to eliminate classification bias. 510 (14.74%) patients developed postoperative AKI. Serum fibrinogen was independently associated with AKI (OR = 1.211, 95% CI 1.080 to 1.358, p = 0.001) after adjustment of covariates. The receiver operator characteristic (ROC) curve for the outcome of AKI, after the addition of serum fibrinogen, had a c-statistic increasing from 0.72 to 0.73 (p < 0.001). This translated to a substantially improved AKI risk classification with a net reclassification index of 0.178 (p < 0.001). After SMOTE subsampling, serum fibrinogen was still independently associated with AKI grade 1 or higher (OR = 1.212, 95% CI 1.1089 to 1.347, p = 0.003). Preoperative serum fibrinogen levels were associated with the risk of postoperative AKI after cardiac valve replacement surgery.

Risk factors and outcomes of sepsis-associated delirium in intensive care unit patients: A secondary data analysis

OBJECTIVE

To identify the risk factors of sepsis-associated delirium and determine their effect on intensive care unit adult patient outcomes.

DESIGN

A secondary analysis of data from system development studies.

SETTING

Korean intensive care unit patients in a university hospital who were diagnosed with sepsis.

METHODS

The risk factors for sepsis-associated delirium were classified into patient factors and sepsis clinical features and were analysed using hierarchical logistic regression analysis. Outcomes included in-hospital mortality, 30-day in-hospital mortality, duration of mechanical ventilation, length of stay in the intensive care unit, length of hospital stay, total medical expenses, discharge placement, re-hospitalisation and visits to the emergency department after discharge.

RESULTS

The risk factor for sepsis-associated delirium including patients aged 65 ≥years, dependent activity and high nursing needs (patient factors), low level of consciousness, tachypnoea, and thrombocytopaenia (clinical features of sepsis). Use of vasopressors/inotropes and albumin decreased the risk of sepsis-associated delirium. Mechanical ventilation duration was prolonged and discharge to skilled nursing facilities was increased by sepsis-associated delirium.

CONCLUSIONS

The risk factors for sepsis-associated delirium increased as the severity of condition for patients with sepsis increased. Early identification of risk factors associated with sepsis-associated delirium may improve patient outcomes.

Cell-free hemoglobin increases inflammation, lung apoptosis, and microvascular permeability in murine polymicrobial sepsis

Increased endothelial permeability is central to the pathogenesis of sepsis and leads to organ dysfunction and death but the endogenous mechanisms that drive increased endothelial permeability are not completely understood. We previously reported that cell-free hemoglobin (CFH), elevated in 80% of patients with sepsis, increases lung microvascular permeability in an ex vivo human lung model and cultured endothelial cells. In this study, we augmented a murine model of polymicrobial sepsis with elevated circulating CFH to test the hypothesis that CFH increases microvascular endothelial permeability by inducing endothelial apoptosis. Mice were treated with an intraperitoneal injection of cecal slurry with or without a single intravenous injection of CFH. Severity of illness, mortality, systemic and lung inflammation, endothelial injury and dysfunction and lung apoptosis were measured at selected time points. We found that CFH added to CS increased sepsis mortality, plasma inflammatory cytokines as well as lung apoptosis, edema and inflammation without affecting large vessel reactivity or vascular injury marker concentrations. These results suggest that CFH is an endogenous mediator of increased endothelial permeability and apoptosis in sepsis and may be a promising therapeutic target.

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.

Endothelium structure and function in kidney health and disease

The kidney harbours different types of endothelia, each with specific structural and functional characteristics. The glomerular endothelium, which is highly fenestrated and covered by a rich glycocalyx, participates in the sieving properties of the glomerular filtration barrier and in the maintenance of podocyte structure. The microvascular endothelium in peritubular capillaries, which is also fenestrated, transports reabsorbed components and participates in epithelial cell function. The endothelium of large and small vessels supports the renal vasculature. These renal endothelia are protected by regulators of thrombosis, inflammation and complement, but endothelial injury (for example, induced by toxins, antibodies, immune cells or inflammatory cytokines) or defects in factors that provide endothelial protection (for example, regulators of complement or angiogenesis) can lead to acute or chronic renal injury. Moreover, renal endothelial cells can transition towards a mesenchymal phenotype, favouring renal fibrosis and the development of chronic kidney disease. Thus, the renal endothelium is both a target and a driver of kidney and systemic cardiovascular complications. Emerging therapeutic strategies that target the renal endothelium may lead to improved outcomes for both rare and common renal diseases.

BK Polyomavirus Virus Glomerular Tropism: Implications for Virus Reactivation from Latency and Amplification during Immunosuppression

BK polyomavirus (BKPyV), or BKV infection, is ubiquitous and usually non-pathogenic, with subclinical infections in 80–90% of adults worldwide. BKV infection is often associated with pathology in immunocompromised individuals. BKV infection often is associated with renal impairment, including ureteral stenosis, hemorrhagic cystitis, and nephropathy. BKV infection is less commonly associated with pneumonitis, retinitis, liver disease, and meningoencephalitis. BKV is known to replicate, establish latency, undergo reactivation, and induce clinical pathology in renal tubular epithelial cells. However, recent in vitro studies support the notion that BKV has expanded tropism-targeting glomerular parenchymal cells of the human kidney, which could impact glomerular function, enhance inflammation, and serve as viral reservoirs for reactivation from latency during immunosuppression. The implications of BKV expanded tropism in the glomerulus, and how specific host and viral factors that would contribute to glomerular inflammation, cytolysis, and renal fibrosis are related to BKV associated nephropathy (BKVAN), have not been explored. The pathogenesis of BKV in human glomerular parenchymal cells is poorly understood. In this review, I examine target cell populations for BKV infectivity in the human glomerulus. Specifically, I explore the implications of BKV expanded tropism in the glomerulus with regard viral entry, replication, and dissemination via cell types exposed to BKV trafficking in glomerulus. I also describe cellular targets shown to be permissive in vitro and in vivo for BKV infection and lytic replication, the potential role that glomerular parenchymal cells play in BKV latency and/or reactivation after immunosuppression, and the rare occurrence of BKV pathology in glomerular parenchymal cells in patients with BKVAN.

Association of endothelial and glycocalyx injury biomarkers with fluid administration, development of acute kidney injury, and 90-day mortality: data from the FINNAKI observational study

Background

Injury to endothelium and glycocalyx predisposes to vascular leak, which may subsequently lead to increased fluid requirements and worse outcomes. In this post hoc study of the prospective multicenter observational Finnish Acute Kidney Injury (FINNAKI) cohort study conducted in 17 Finnish intensive care units, we studied the association of Syndecan-1 (SDC-1), Angiopoetin-2 (Ang-2), soluble thrombomodulin (sTM), vascular adhesion protein-1 (VAP-1) and interleukin-6 (IL-6) with fluid administration and balance among septic critical care patients and their association with development of acute kidney injury (AKI) and 90-day mortality.

Results

SDC-1, Ang-2, sTM, VAP-1 and IL-6 levels were measured at ICU admission from 619 patients with sepsis. VAP-1 decreased (p < 0.001) and IL-6 increased (p < 0.001) with increasing amounts of administered fluid, but other biomarkers did not show differences according to fluid administration. In linear regression models adjusted for IL-6, only VAP-1 was significantly associated with fluid administration on day 1 (p < 0.001) and the cumulative fluid balance on day 5/ICU discharge (p = 0.001). Of 415 patients admitted without AKI, altogether 112 patients (27.0%) developed AKI > 12 h from ICU admission (AKI_>12 h). They had higher sTM levels than patients without AKI, and after multivariable adjustment log, sTM level was associated with AKI_>12 h with OR (95% CI) of 12.71 (2.96–54.67), p = 0.001). Ninety-day non-survivors (n = 180; 29.1%) had higher SDC-1 and sTM levels compared to survivors. After adjustment for known confounders, log SDC-1 (OR [95% CI] 2.13 [1.31–3.49], p = 0.002), log sTM (OR [95% CI] 7.35 [2.29–23.57], p < 0.001), and log Ang-2 (OR [95% CI] 2.47 [1.44–4.14], p = 0.001) associated with an increased risk for 90-day mortality. Finally, patients who had high levels of all three markers, namely, SDC-1, Ang-2 and sTM, had an adjusted OR of 5.61 (95% CI 2.67–11.79; p < 0.001) for 90-day mortality.

Conclusions

VAP-1 and IL-6 associated with fluid administration on the first ICU day. After adjusting for confounders, sTM was associated with development of AKI after 12 h from ICU admission. SDC-1, Ang-2 and sTM were independently associated with an increased risk for 90-day mortality.

Coagulative biomarkers on admission to the ICU predict acute kidney injury and mortality in patients with septic shock caused by intra-abdominal infection

Purpose

Sepsis-associated coagulopathy (SAC) contributes to the development of multiple organ failure (MOF) and increasing mortality. The present study was conducted to investigate whether coagulative biomarkers on admission to the intensive care unit (ICU) can predict acute kidney injury (AKI) and mortality in patients with septic shock caused by intra-abdominal infection (IAI).

Patients and methods

An observational retrospective study was conducted in the surgical ICU. We studied patients who met the criteria of septic shock (Sepsis-3) caused by IAI between January 1, 2013, and December 31, 2016. By adjusting for baseline characteristics, multivariate regression analyses were employed to identify independent risk factors for predicting AKI and mortality.

Results

Of the 138 enrolled patients, 65 patients developed AKI. The patients who developed AKI exhibited a dramatically higher Sequential Organ Failure Assessment (SOFA) score (median, 12), Acute Physiology and Chronic Health Evaluation (APACHE) II score (median, 27.5) and mortality rate. In both models, we found that activated partial thromboplastin time (APTT) (odds ratio (OR)=1.074, 95% confidence interval (CI) 1.030-1.120, p=0.001), prothrombin time (PT) (OR=1.162, 95% CI 1.037-1.302, p=0.010) and D-dimer level (OR=1.098, 95% CI 1.002-1.202, p=0.045) on admission to the ICU were significant risk factors for AKI. Moreover, Cox regression analysis showed that prolonged APTT (OR=1.065, 95% CI 1.025-1.107, p=0.001) was independently associated with high mortality.

Conclusion

In patients with septic shock caused by IAI, APTT, PT and D-dimer level on admission to the ICU were significantly associated with AKI. Furthermore, APTT was an independent predictor of 30-day mortality.

Postreperfusion plasma endothelial activation markers are associated with acute kidney injury after lung transplantation

Acute kidney injury (AKI) is common after lung transplantation, but molecular markers remain poorly studied. The endothelial activation markers soluble thrombomodulin (sTM), protein C, and plasminogen activator inhibitor-1 (PAI-1) are implicated in kidney microcirculatory injury in animal models of AKI. We tested the association of 6-hour postreperfusion plasma levels of these markers with posttransplant AKI severity in patients enrolled in the Lung Transplant Outcomes Group prospective cohort study at the University of Pennsylvania during two eras: 2004-06 (n = 61) and 2013-15 (n = 67). We defined AKI stage through postoperative day 5 using Kidney Disease Improving Global Outcomes creatinine criteria. We used multivariable ordinal logistic regression to determine the association of each biomarker with AKI, adjusted for primary graft dysfunction and extracorporeal life support. AKI occurred in 57 (45%) patients across both eras: 28 (22%) stage 1, 29 (23%) stage 2-3. Higher sTM and lower protein C plasma levels were associated with AKI stage in each era and remained so in multivariable models utilizing both eras (sTM: OR 1.76 [95% CI 1.19-2.60] per standard deviation, P = .005; protein C: OR 0.54 [1.19-2.60], P = .003). We conclude that 6-hour postreperfusion plasma sTM and protein C levels are associated with early postlung transplant AKI severity.

Acute kidney injury from sepsis: current concepts, epidemiology, pathophysiology, prevention and treatment

Sepsis-associated acute kidney injury (S-AKI) is a frequent complication of the critically ill patient and is associated with unacceptable morbidity and mortality. Prevention of S-AKI is difficult because by the time patients seek medical attention, most have already developed acute kidney injury. Thus, early recognition is crucial to provide supportive treatment and limit further insults. Current diagnostic criteria for acute kidney injury has limited early detection; however, novel biomarkers of kidney stress and damage have been recently validated for risk prediction and early diagnosis of acute kidney injury in the setting of sepsis. Recent evidence shows that microvascular dysfunction, inflammation, and metabolic reprogramming are 3 fundamental mechanisms that may play a role in the development of S-AKI. However, more mechanistic studies are needed to better understand the convoluted pathophysiology of S-AKI and to translate these findings into potential treatment strategies and add to the promising pharmacologic approaches being developed and tested in clinical trials.

Thrombomodulin, Plasminogen Activator Inhibitor-1 and Protein C Levels, and Organ Dysfunction in Sepsis

Since endothelial function is closely related to organ dysfunction in sepsis and the relationship among endothelial injury, organ dysfunction, and other biomarkers remains unclear, we aimed to evaluate the correlation among endothelial injury, organ dysfunction, and several biomarkers in patients with sepsis.

Design

This was a retrospective observational study.

Setting

The study was conducted in a university hospital with 14 mixed ICU beds.

Patients

ICU patients with sepsis from June 2011 to December 2017 were enrolled in this study.

Interventions

Endothelial biomarkers (soluble thrombomodulin, plasminogen activator inhibitor-1, and protein C) and markers of inflammation and coagulation were evaluated during the ICU stay. Sequential Organ Failure Assessment scores were assessed for 7 days after ICU admission to determine organ dysfunction. Variables were compared among five stratified groups according to the Sequential Organ Failure Assessment score (0-2, 3-5, 6-8, 9-12, and 13-24). Regression analysis and 95% CIs were used to evaluate trends in biomarkers.

Measurements and Main Results

The patients were divided into five stratified groups (Sequential Organ Failure Assessment 0-2, n = 159 [20.5%]; Sequential Organ Failure Assessment 3-5, n = 296 [38.2%]; Sequential Organ Failure Assessment 6-8, n = 182 [23.5%]; Sequential Organ Failure Assessment 9-12, n = 75 [9.7%]; Sequential Organ Failure Assessment 13-24, n = 31 [4.0%]). Protein C activity was significantly correlated with the severity of organ dysfunction. It was lower on day 1, increased upon successful treatment, and was significantly higher in groups with lower Sequential Organ Failure Assessment scores.

Conclusions

Trends and activity of protein C were superior in predicting organ dysfunction compared with other endothelial biomarkers. Monitoring the level of protein C activity is an ideal tool to monitor organ dysfunctions in patients with sepsis.

The utility of neutrophil gelatinase-associated Lipocalin (NGAL) as a marker of acute kidney injury (AKI) in critically ill patients

In current clinical practice, Serum Creatinine (SCr) is a commonly used marker for the diagnosis of acute kidney injury (AKI). Unfortunately, due to a delayed increase in SCr, it is unable to accurately estimate the timing of the injury. The purpose of this study was to assess the ability of plasma neutrophil gelatinase-associated lipocalin (pNGAL) to predict AKI in critically ill adult patients. The study was conducted at the Section of Chemical Pathology, Department of Pathology& Laboratory Medicine in collaboration with Department of Anesthesiology, at Aga Khan University Hospital in Karachi, Pakistan. Subjects in the age groups of18 to 60, that were admitted into the intensive care unit (ICU) with suspected sepsis were enrolled in this study.AKI was labeled by using Risk-Injury-Failure-loss-End Stage (RIFLE) criteria. Forty-eight patients, mean age being 46.5 ± 16.3, were recruited over a nine-month period. Multiple blood samples were collected from each patient at 12 h, 24 h, and 48 h. A total of 52.1% (n = 24) of ICU patients suspected of sepsis had developed AKI. Baseline characteristics of subjects with AKI were compared to those without AKI. Statistically significant difference was noted in gender (p-value< 0.05) and pNGAL (p-value< 0.001). However, no significant differences were seen with respect to age, in patients with and without AKI. The area under the curve (AUC) at12hr was 0.82 (95% CI 0.68-0.96) with a sensitivity of 70.8% and specificity of 90.9%.While AUCs at 24 h was 0.86(95% CI 0.74-0.97) with a sensitivity of 78.5% and specificity of 88.8%. Furthermore, there was a positive correlation between pNGAL and the length of ICU stay (r = 0.98). Non-survivors or expired patients had higher median pNGAL170 (202-117) ng/ml as compared to survivors 123(170-91) ng/ml. In conclusion, pNGAL is an early predictor of AKI in a heterogeneous adult ICU population. Plasma NGAL allows the diagnosis of AKI 48 h prior to a clinical diagnosis based on RIFLE criteria. Early identification of high-risk AKI in patients may allow earlier initiation of therapies and improve patient outcome.

Endothelium structure and function in kidney health and disease

The kidney harbours different types of endothelia, each with specific structural and functional characteristics. The glomerular endothelium, which is highly fenestrated and covered by a rich glycocalyx, participates in the sieving properties of the glomerular filtration barrier and in the maintenance of podocyte structure. The microvascular endothelium in peritubular capillaries, which is also fenestrated, transports reabsorbed components and participates in epithelial cell function. The endothelium of large and small vessels supports the renal vasculature. These renal endothelia are protected by regulators of thrombosis, inflammation and complement, but endothelial injury (for example, induced by toxins, antibodies, immune cells or inflammatory cytokines) or defects in factors that provide endothelial protection (for example, regulators of complement or angiogenesis) can lead to acute or chronic renal injury. Moreover, renal endothelial cells can transition towards a mesenchymal phenotype, favouring renal fibrosis and the development of chronic kidney disease. Thus, the renal endothelium is both a target and a driver of kidney and systemic cardiovascular complications. Emerging therapeutic strategies that target the renal endothelium may lead to improved outcomes for both rare and common renal diseases.

Endothelial biomarkers in human sepsis: pathogenesis and prognosis for ARDS

Experimental models of sepsis in small and large animals and a variety of in vitro preparations have established several basic mechanisms that drive endothelial injury. This review is focused on what can be learned from the results of clinical studies of plasma biomarkers of endothelial injury and inflammation in patients with sepsis. There is excellent evidence that elevated plasma levels of several biomarkers of endothelial injury, including von Willebrand factor antigen (VWF), angiopoietin-2 (Ang-2), and soluble fms-like tyrosine kinase 1 (sFLT-1), and biomarkers of inflammation, especially interleukin-8 (IL-8) and soluble tumor necrosis factor receptor (sTNFr), identify sepsis patients with a higher mortality. There are also some data that elevated levels of endothelial biomarkers can identify which patients with non-pulmonary sepsis will develop acute respiratory distress syndrome (ARDS). If ARDS patients are divided among those with indirect versus direct lung injury, then there is an association of elevated levels of endothelial biomarkers in indirect injury and markers of inflammation and alveolar epithelial injury in patients with direct lung injury. New research suggests that the combination of biologic and clinical markers may make it possible to segregate patients with ARDS into hypo- versus hyper-inflammatory phenotypes that may have implications for therapeutic responses to fluid therapy. Taken together, the studies reviewed here support a primary role of the microcirculation in the pathogenesis and prognosis of ARDS after sepsis. Biological differences identified by molecular patterns could explain heterogeneity of treatment effects that are not explained by clinical factors alone.