Renal microvascular endothelial cell responses in sepsis-induced acute kidney injury

Endothelial cells in the kidney microvasculature have an intrinsic molecular and phenotypic heterogeneity and respond to sepsis-induced acute kidney injury conditions in a segment-specific manner. This Review discusses the roles of these cells and the molecular systems that control endothelial functions in the development of sepsis-induced acute kidney injury. Microvascular endothelial cells in the kidney have been a neglected cell type in sepsis-induced acute kidney injury (sepsis-AKI) research; yet, they offer tremendous potential as pharmacological targets. As endothelial cells in distinct cortical microvascular segments are highly heterogeneous, this Review focuses on endothelial cells in their anatomical niche. In animal models of sepsis-AKI, reduced glomerular blood flow has been attributed to inhibition of endothelial nitric oxide synthase activation in arterioles and glomeruli, whereas decreased cortex peritubular capillary perfusion is associated with epithelial redox stress. Elevated systemic levels of vascular endothelial growth factor, reduced levels of circulating sphingosine 1-phosphate and loss of components of the glycocalyx from glomerular endothelial cells lead to increased microvascular permeability. Although coagulation disbalance occurs in all microvascular segments, the molecules involved differ between segments. Induction of the expression of adhesion molecules and leukocyte recruitment also occurs in a heterogeneous manner. Evidence of similar endothelial cell responses has been found in kidney and blood samples from patients with sepsis. Comprehensive studies are needed to investigate the relationships between segment-specific changes in the microvasculature and kidney function loss in sepsis-AKI. The application of omics technologies to kidney tissues from animals and patients will be key in identifying these relationships and in developing novel therapeutics for sepsis

Reduced Tie2 in Microvascular Endothelial Cells Is Associated with Organ-Specific Adhesion Molecule Expression in Murine Health and Endotoxemia

Endothelial cells (ECs) in the microvasculature in organs are active participants in the pathophysiology of sepsis. Tyrosine protein kinase receptor Tie2 (Tek; Tunica interna Endothelial cell Kinase) is thought to play a role in their inflammatory response, yet data are inconclusive. We investigated acute endotoxemia-induced changes in the expression of Tie2 and inflammation-associated endothelial adhesion molecules E-selectin and VCAM-1 (vascular cell adhesion molecule-1) in kidneys and lungs in inducible, EC-specific Tie2 knockout mice. The extent of Tie2 knockout in healthy mice differed between microvascular beds, with low to absent expression in arterioles in kidneys and in capillaries in lungs. In kidneys, Tie2 mRNA dropped more than 70% upon challenge with lipopolysaccharide (LPS) in both genotypes, with no change in protein. In renal arterioles, tamoxifen-induced Tie2 knockout was associated with higher VCAM-1 protein expression in healthy conditions. This did not increase further upon challenge of mice with LPS, in contrast to the increased expression occurring in control mice. Also, in lungs, Tie2 mRNA levels dropped within 4 h after LPS challenge in both genotypes, while Tie2 protein levels did not change. In alveolar capillaries, where tamoxifen-induced Tie2 knockout did not affect the basal expression of either adhesion molecule, a 4-fold higher E-selectin protein expression was observed after exposure to LPS compared to controls. The here-revealed heterogeneous effects of absence of Tie2 in ECs in kidney and lung microvasculature in health and in response to acute inflammatory activation calls for further in vivo investigations into the role of Tie2 in EC behavior. </p

Requirement of respiratory support in acute bronchiolitis in infants is linked to endothelial and neutrophil activation

BACKGROUND: Evidence shows that activation of pulmonary vascular endothelium and neutrophils are involved in the pathophysiology of acute bronchiolitis. We hypothesized that levels of markers of endothelial activation and leukocyte counts are associated with requirement and duration of respiratory support. METHODS: Thirty-four infants with bronchiolitis and eight controls were included. Nasopharyngeal swabs and blood samples were taken at admission. Serum levels of Angiopoietin (Ang)-1, Ang-2, sP-selectin, sE-selectin, vascular cell adhesion molecule-1 (sVCAM-1), intercellular adhesion molecule-1 (sICAM-1), and leukocyte counts were measured. For univariate analysis, bronchiolitis cases were grouped into two groups, namely those not requiring and those requiring any form of respiratory support. To control for known risk factors for poor outcome (i.e., age, prematurity, and congenital heart disease), and for days post symptom onset, linear regression analysis was performed with duration of any type of respiratory support in days. RESULTS: Ang-2 levels, Ang-2/Ang-1 ratios, sE-selectin levels, immature neutrophil count, and neutrophil/lymphocyte ratio (NLR) were higher in acute bronchiolitis versus controls. Ang-2, and NLR levels were significantly higher, and lymphocyte counts significantly lower, in infants that required respiratory support versus those that did not. Ang-2 levels (β: .32, 95% confidence interval [CI]: 0.19-1.19) and NLR (β: .68, 95% CI: 0.17-1.19) were positive predictors for the duration of respiratory support. CONCLUSIONS: Markers of endothelial and neutrophil activation are associated with respiratory support for acute bronchiolitis. Admission Ang-2 levels and NLR may be promising markers to determine requirement of respiratory support and deserve further study

Hydrocortisone-associated death and hospital length of stay in patients with sepsis:A retrospective cohort of large-scale clinical care data

PURPOSE: Sepsis is one of the leading causes of morbidity and mortality worldwide with approximately 50 million annual cases. There is ongoing debate on the clinical benefit of hydrocortisone in the prevention of death in septic patients. Here we evaluated the association between hydrocortisone treatment and mortality in patients diagnosed with sepsis in a large-scale clinical dataset.METHODS: Data from patients between 2008 and 2019 were extracted from the retrospective Medical Information Mart for Intensive Care IV (MIMIC-IV) database. Patients who received hydrocortisone after diagnosis were matched using propensity-score matching with patients who did not, to balance confounding (by indication and contraindication) factors between the groups. 90-day mortality and survivors' length of hospital stay was compared between patients who did or did not receive hydrocortisone.RESULTS: A total of 31,749 septic patients were included in the study (mean age: 67, men: 57.3%, in-hospital mortality: 15.6%). 90-day mortality was higher among the 1802 patients receiving hydrocortisone when compared with the 6348 matched non-users (hazard ratio: 1.35, 95% CI: 1.24-1.47). Hydrocortisone treatment was also associated with increased in-hospital mortality (40.9% vs. 27.6%, p &lt; 0.0001) and prolonged hospital stay in those who survived until discharge (median 12.6 days vs. 10.8 days, p &lt; 0.0001). Stratification for age, gender, ethnicity, occurrence of septic shock, and the need for vasopressor drug administration such as (nor)epinephrine did not reveal sub-population(s) benefiting of hydrocortisone use.CONCLUSION: Hydrocortisone treatment is associated with increased risk of death as well as prolonged hospital stay in septic patients. Although residual confounding (by indication) cannot be ruled out completely due to the observational nature of the study, the present study suggests clinical implication of hydrocortisone use in patients with sepsis.</p

Hydrocortisone-associated death and hospital length of stay in patients with sepsis:A retrospective cohort of large-scale clinical care data

PURPOSE: Sepsis is one of the leading causes of morbidity and mortality worldwide with approximately 50 million annual cases. There is ongoing debate on the clinical benefit of hydrocortisone in the prevention of death in septic patients. Here we evaluated the association between hydrocortisone treatment and mortality in patients diagnosed with sepsis in a large-scale clinical dataset.METHODS: Data from patients between 2008 and 2019 were extracted from the retrospective Medical Information Mart for Intensive Care IV (MIMIC-IV) database. Patients who received hydrocortisone after diagnosis were matched using propensity-score matching with patients who did not, to balance confounding (by indication and contraindication) factors between the groups. 90-day mortality and survivors' length of hospital stay was compared between patients who did or did not receive hydrocortisone.RESULTS: A total of 31,749 septic patients were included in the study (mean age: 67, men: 57.3%, in-hospital mortality: 15.6%). 90-day mortality was higher among the 1802 patients receiving hydrocortisone when compared with the 6348 matched non-users (hazard ratio: 1.35, 95% CI: 1.24-1.47). Hydrocortisone treatment was also associated with increased in-hospital mortality (40.9% vs. 27.6%, p &lt; 0.0001) and prolonged hospital stay in those who survived until discharge (median 12.6 days vs. 10.8 days, p &lt; 0.0001). Stratification for age, gender, ethnicity, occurrence of septic shock, and the need for vasopressor drug administration such as (nor)epinephrine did not reveal sub-population(s) benefiting of hydrocortisone use.CONCLUSION: Hydrocortisone treatment is associated with increased risk of death as well as prolonged hospital stay in septic patients. Although residual confounding (by indication) cannot be ruled out completely due to the observational nature of the study, the present study suggests clinical implication of hydrocortisone use in patients with sepsis.</p

Serum concentrations of endothelial cell adhesion molecules and their shedding enzymes and early onset sepsis in newborns in Suriname

Background: Early onset sepsis (EOS) is defined as onset of sepsis within 72 hours after birth. Leucocyte-endothelial interactions play a pivotal part in EOS pathophysiology. Endothelial cell adhesion molecules (CAMs) orchestrate these interactions and their soluble isoforms (sCAMs) are released into the vasculature by enzymes called sheddases. Purpose: This study was undertaken to explore further the pathophysiology of EOS and to investigate the potential of sCAM and their sheddases as potential biomarkers for EOS. Methods: Stored serum aliquots were used from 71 Surinamese newborns suspected of EOS and 20 healthy newborns from an earlier study. Serum had been collected within 72 hours after birth and six (8.6%) newborns had a positive blood culture with gram-negative pathogens. Concentrations of sCAMs sP-selectin, sE-selectin, soluble vascular cell adhesion molecule-1, intercellular adhesion molecule-1 and platelet and endothelial cell adhesion molecule-1, sheddases matrix metalloproteinase-9 (MMP-9) and neutrophil elastase (NE) and sheddase antagonist tissue-inhibitor of metalloproteinases-1 (TIMP-1) were measured simultaneously with Luminex and ELISA. Results: MMP-9 and TIMP-1 levels were measured in serum of n=91 newborns and sCAMs and NE levels in serum of n=80 newborns, respectively. We found no differences in median concentrations of sCAMs, MMP-9 and TIMP-1 or NE between blood culture positive EOS, blood culture negative EOS and control groups at start of antibiotic treatment. Conclusions: Our data indicate that serum concentrations of sCAMs and their sheddases have no clinical utility as biomarkers for EOS. Trial registration number: NCT02486783. Results

Protocol of the sepsivit study:A prospective observational study to determine whether continuous heart rate variability measurement during the first 48 hours of hospitalisation provides an early warning for deterioration in patients presenting with infection or sepsis to the emergency department of a Dutch academic teaching hospital

INTRODUCTION: One in five patients with sepsis deteriorates within 48 hours after hospital admission. Regrettably, a clear tool for the early detection of deterioration is still lacking. The SepsiVit study aims to determine whether continuous heart rate variability (HRV) measurement can provide an early warning for deterioration in patients presenting with suspected infection or sepsis to the emergency department (ED). METHODS AND ANALYSIS: The protocol of a prospective observational study in the ED. We will include 171 adult medical patients presenting with suspected infection or sepsis and at least two systemic inflammatory response syndrome criteria. Patients with known pregnancy, cardiac transplantation or not admitted to our hospital are excluded.High sample frequency ECG signals (500 Hz), respiratory rate, blood pressure and peripheral oxygen saturation will be recorded continuously during the first 48 hours of hospitalisation using a bedside patient monitor (Philips IntelliVue MP70). Primary endpoint is patient deterioration, defined as the development of organ dysfunction, unplanned intensive care unit admission or in-hospital mortality. The ECG data will be used for offline HRV analysis. We will compare the HRV between two groups (deterioration/no deterioration) and analyse whether HRV provides an early warning for deterioration. Furthermore, we will create a multivariate predictive model for deterioration based on heart rate, respiratory rate and HRV. As planned secondary analyses, we (1) perform a subgroup analysis for patients with pneumosepsis and urosepsis and (2) determine whether HRV using lower sample frequencies (1 Hz or less) suffices to predict deterioration. ETHICS AND DISSEMINATION: The Institutional Review Board of the University Medical Center Groningen granted a waiver for the study (METc 2015/164). Results will be disseminated through international peer-reviewed publications and conference presentations. A lay summary of the results will be provided to the study participants. TRIAL REGISTRATION NUMBER: NTR6168; Pre-results

Acute and chronic histopathological findings in renal biopsies in COVID-19

The dominant ICU admission diagnosis of COVID-19 patients is respiratory insufficiency, but 32–57% of hospitalized COVID-19 patients develop acute kidney injury (COVID-AKI). The renal histopathological changes accompanying COVID-AKI are not yet fully described. To obtain a detailed insight into renal histopathological features of COVID-19, we conducted a review including all studies reporting histopathological findings of diagnostic and postmortem kidney biopsies from patients with COVID-19 published between January 1, 2020, and January 31, 2021. A total of 89 diagnostic and 194 postmortem renal biopsies from individual patients in 39 published studies were investigated and were included in the analysis. In the diagnostic biopsy group, mean age was 56 years and AKI incidence was 96%. In the postmortem biopsy group, mean age was 69 years and AKI incidence was 80%. In the diagnostic biopsy group, the prevalence of acute glomerular diseases was 74%. The most common glomerular lesions were collapsing focal segmental glomerulosclerosis (c-FSGS) in 54% and thrombotic microangiopathy (TMA) in 9% of patients. TMA was also found in 10% of patients in the postmortem biopsy group. The most common acute tubular lesions was acute tubular necrosis (ATN) which was present in 87% of patients in the diagnostic and in 77% of patients in the postmortem biopsy group. Additionally, we observed a high prevalence of preexisting chronic lesions in both groups such as atherosclerosis and glomerulosclerosis. Histopathological changes in renal biopsies of COVID-19 patients show a heterogeneous picture with acute glomerular lesions, predominantly c-FSGS and TMA, and acute tubular lesions, predominantly ATN. In many patients, these lesions were present on a background of chronic renal injury. GRAPHICAL ABSTRACT: [Image: see text] SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10238-022-00941-x