Siglec-7 as a Novel Biomarker to Predict Mortality in Decompensated Cirrhosis and Acute Kidney Injury

Healthcare Resource Utilization and Goals of Care Discussions in Patients with Cirrhosis and Acute Kidney Injury

BACKGROUND

Patients with cirrhosis and acute kidney injury (AKI) are critically ill and have high health care resource utilization (HCRU). The impact and timing of goals of care discussions on HCRU are not well described.

METHODS

221 patients enrolled in a prospective cohort study of patients admitted with AKI and cirrhosis were reviewed. Documentation and timing of a goals of care discussions were analyzed as predictors of HCRU, defined as a composite outcome of intubation, initiation of renal replacement therapy, and/or admission to the intensive care unit.

RESULTS

Median MELD score was 26 [IQR 19, 33]. 29% patients were listed for liver transplant. 90-day mortality was 61%. 51% patients had at least one HCRU episode. Code status changed from admission to discharge from 91%/7%/0% to 68%/14%18% (full code/do not resuscitate/comfort measures, p < 0.001). 28% patients underwent goals of care discussions, with change in code status at a median of 16 [9, 22] days into admission. Only 18% of discussions were within 7 days of admission and all were after an HCRU event. Being listed for liver transplant was not associated with whether goals of care discussions occurred (23% listed vs. 31% non-listed, p = 0.24) but was associated with higher HCRU (69% vs. 43%; p < 0.001).

CONCLUSION

Goals of care discussions occurred late into the hospital course, after episodes of HCRU. Efforts should be made to engage in these discussions earlier in the hospital stay, which may decrease HCRU rates in this critically ill population and align with patients' goals of care.

A new algorithm shows superior ability to discriminate liver fibrosis stages in chronic hepatitis C

Previous evidence suggests that sialic acid-binding Ig-like lectin 7 (Siglec-7) protein is significantly increased in patients with chronic hepatitis C virus (HCV) infection and directly correlates with clinical parameters of liver inflammation and fibrosis. The aim of this study was to determine the diagnostic value of Siglec-7 as a non-invasive tool to assess liver fibrosis in patients with chronic hepatitis C in a cross-sectional study. Serum levels of Siglec-7 were retrospectively tested in 1007 consecutive patients with chronic HCV infection recruited at three different European sites and data examined by the 'imperfect gold-standard' statistical analysis. Liver stiffness obtained by transient elastography (TE) was considered the standard reference. Liver fibrosis was staged according to published cut-offs of liver stiffness measurement by TE. Accuracy of detection of liver fibrosis stage was not increased by Siglec-7 alone. However, we developed a new index (SiGAP) including Siglec-7, γ-glutamyl transferase, age and platelet count which showed increased sensitivity and specificity in predicting fibrosis compared with APRI or FIB4 indices. The AUROC of SiGAP for the diagnosis of significant (≥F2) and advanced liver fibrosis (≥F3) showed significantly higher values than those of APRI and FIB-4. Siglec-7 may be useful as a complementary tool to assess liver fibrosis stage in patients with chronic hepatitis C when included in a specifically designed algorithm, which showed high level of accuracy in the detection of F2 and F3 fibrosis stage.

Current knowledge about biomarkers of acute kidney injury in liver cirrhosis

Acute kidney injury (AKI) is common in advanced cirrhosis. Prerenal azotemia, hepatorenal syndrome, and acute tubular necrosis are the main causes of AKI in patients with cirrhosis. Evaluation of renal function and differentiation between functional and structural kidney injury are important issues in the management of cirrhosis. However, AKI in cirrhosis exists as a complex clinical spectrum rather than concrete clinical entity. Based on current evidence, changes in serum creatinine (Cr) levels remain the most appropriate standard for defining AKI in cirrhosis. However, serum Cr has a limited role in assessing renal function in this population. This review examines previous studies that investigated the ability of recent biomarkers for AKI in cirrhosis from the perspective of earlier and accurate diagnosis, classification of AKI phenotype, and prediction of clinical outcomes. Serum cystatin C and urine neutrophil gelatinase-associated lipocalin have been extensively studied in cirrhosis, and have facilitated improved diagnosis and prognosis prediction in patients with AKI. In addition, urine N-acetyl-β-D-glucosaminidase, interleukin 18, and kidney injury molecule 1 are other promising biomarkers for advanced cirrhosis. However, the clinical significance of these markers remains unclear because there are no cut-off values defining the normal range and differentiating phenotypes of AKI. In addition, AKI has been defined in terms of serum Cr, and renal biopsy-the gold standard-has not been carried out in most studies. Further discovery of innovate biomarkers and incorporation of various markers could improve the diagnosis and prognosis prediction of AKI, and will translate into meaningful improvements in patient outcomes.

Human Natural Killer Receptors, Co-Receptors, and Their Ligands

In the last 20 years, the study of human natural killer (NK) cells has moved from the first molecular characterizations of very few receptor molecules to the identification of a plethora of receptors displaying surprisingly divergent functions. We have contributed to the description of inhibitory receptors and their signaling pathways, important in fine regulation in many cell types, but unknown until their discovery in the NK cells. Inhibitory function is central to regulating NK-mediated cytolysis, with different molecular structures evolving during speciation to assure its persistence. More recently, it has become possible to characterize the NK triggering receptors mediating natural cytotoxicity, unveiling the existence of a network of cellular interactions between effectors of both natural and adaptive immunity. This unit reviews the contemporary history of molecular studies of receptors and ligands involved in NK cell function, characterizing the ligands of the triggering receptor and the mechanisms for finely regulating their expression in pathogen-infected or tumor cells. © 2018 by John Wiley & Sons, Inc.

Serum Angiopoietin-2 Predicts Mortality and Kidney Outcomes in Decompensated Cirrhosis

Acute kidney injury in decompensated cirrhosis has limited therapeutic options, and novel mechanistic targets are urgently needed. Angiopoietin-2 is a context-specific antagonist of Tie2, a receptor that signals vascular quiescence. Considering the prominence of vascular destabilization in decompensated cirrhosis, we evaluated Angiopoietin-2 to predict clinical outcomes. Serum Angiopoietin-2 was measured serially in a prospective cohort of hospitalized patients with decompensated cirrhosis and acute kidney injury. Clinical characteristics and outcomes were examined over a 90-day period and analyzed according to Angiopoietin-2 levels. Primary outcome was 90-day mortality. Our study included 191 inpatients (median Angiopoietin-2 level 18.2 [interquartile range 11.8, 26.5] ng/mL). Median Model for End-Stage Liver Disease (MELD) score was 23 [17, 30] and 90-day mortality was 41%. Increased Angiopoietin-2 levels were associated with increased mortality (died 21.9 [13.9, 30.3] ng/mL vs. alive 15.2 [9.8, 23.0] ng/mL; P < 0.001), higher Acute Kidney Injury Network stage (stage I 13.4 [9.8, 20.1] ng/mL vs. stage II 20.0 [14.1, 26.2] ng/mL vs. stage III 21.9 [13.0, 29.5] ng/mL; P = 0.002), and need for renal replacement therapy (16.5 [11.3, 23.6] ng/mL vs. 25.1 [13.3, 30.3] ng/mL; P = 0.005). The association between Angiopoietin-2 and mortality was significant in unadjusted and adjusted Cox regression models (P ≤ 0.001 for all models), and improved discrimination for mortality when added to MELD score (integrated discrimination increment 0.067; P = 0.001). Conclusion: Angiopoietin-2 was associated with mortality and other clinically relevant outcomes in a cohort of patients with decompensated cirrhosis with acute kidney injury. Further experimental study of Angiopoietin/Tie2 signaling is warranted to explore its potential mechanistic and therapeutic role in this population.