Biomarker-guided management of acute kidney injury

PURPOSE OF REVIEW

The current narrative review discusses practical applications of stress and damage biomarkers for the management of acute kidney injury (AKI) based on clinical trials and real-world evaluations.

RECENT FINDINGS

In 2013 with the discovery and validation study of biomarkers for AKI (Sapphire) advancement in care was provided allowing for the early identification of patients at high risk for developing AKI. It was the combination of new biomarkers and the Kidney Disease Improving Global Outcomes (KDIGO) guidelines for managing patients with AKI that provided an opportunity to improve patient care. In 2017, the PrevAKI study implemented KDIGO guideline management in high-risk patients identified by biomarkers followed in 2018 with the BigPAK study that used a similar approach, both of which demonstrated positive outcomes in patient care. Next, real-world evaluations followed supporting biomarker guided management of AKI in clinical practice. Also, proposals for better nephrotoxin management, a major modifiable exposure to prevent AKI, were provided with the foresight in identifying high-risk patients.

SUMMARY

Stress and damage biomarker-based approaches to patient care seem to be promising for identifying patients at high risk for developing AKI and thus offers an opportunity for early management to prevent and ameliorate AKI and drug-associated AKI.

Clinical Relevance and Predictive Value of Damage Biomarkers of Drug-Induced Kidney Injury

Nephrotoxin exposure accounts for up to one-fourth of acute kidney injury episodes in hospitalized patients, and the associated consequences are as severe as acute kidney injury due to other etiologies. As the use of nephrotoxic agents represents one of the few modifiable risk factors for acute kidney injury, clinicians must be able to identify patients at high risk for drug-induced kidney injury rapidly. Recently, significant advancements have been made in the field of biomarker utilization for the prediction and detection of acute kidney injury. Such biomarkers may have a role both for detection of drug-induced kidney disease and implementation of preventative and therapeutic strategies designed to mitigate injury. In this article, basic principles of renal biomarker use in practice are summarized, and the existing evidence for six markers specifically used to detect drug-induced kidney injury are outlined, including liver-type fatty acid binding protein, neutrophil gelatinase-associated lipocalin, tissue inhibitor of metalloproteinase-2 times insulin-like growth factor-binding protein 7 ([TIMP-2]·[IGFBP7]), kidney injury molecule-1 and N-acetyl-β-D-glucosaminidase. The results of the literature search for these six kidney damage biomarkers identified 29 unique articles with none detected for liver-type fatty acid binding protein and [TIMP-2]·[IGFBP7]. For three biomarkers, kidney injury molecule-1, neutrophil gelatinase-associated lipocalin and N-acetyl-β-D-glucosaminidase, the majority of the studies suggest utility in clinical practice. While many questions need to be answered to clearly articulate the use of biomarkers to predict drug-induced kidney disease, current data are promising.

Adipokines levels in HIV infected patients: lipocalin-2 and fatty acid binding protein-4 as possible markers of HIV and antiretroviral therapy-related adipose tissue inflammation

Background

Metabolic and cardiovascular diseases (CVD) represent a major problem in HIV infection. The aim of this study was to evaluate the relationship of HIV infection and antiretroviral therapy (ART) with circulating levels of two adipokines (Lipocalin-2 and Fatty Acid Binding Protein-4, FABP-4), known to be associated with adipose tissue dysfunction and cardiovascular disease in the general population.

Methods

We enrolled 40 non-obese HIV-infected patients and 10 healthy controls of similar age and Body Mass Index (BMI). Body composition, metabolic syndrome, lipid profile, 10-years CVD risk score, and adipokines levels were compared between groups. ART-regimen status (naïve, non-nucleoside reverse transcriptase inhibitors – NNRTIs – and protease inhibitors – PIs) association with adipokines levels was tested with linear regression models.

Results

HIV patients showed a worse metabolic profile than controls. Lipocalin-2 levels were higher in HIV-infected subjects (+53%; p = 0.007), with a significant trend (p = 0.003) for higher levels among subjects taking NNRTIs. Association of lipocalin-2 with fat-mass and BMI was modulated by ART regimens, being positive among subjects treated with NNRTIs and negative among those treated with PIs (“ART-regimens-by-BMI” interaction p = 0.0009). FABP-4 levels were correlated with age, fat mass, BMI, lipid profile and CVD risk (all R ≥ 0.32, p < 0.05), but not influenced by HIV-status (+20%; p = 0.12) or ART-regimen (p = 0.4).

Conclusions

Our data confirm that HIV-infection is associated with adipose tissue inflammation, as measured by Lipocalin-2 levels, and ART does not attenuate this association. While FABP-4 is a marker of worse metabolic and CVD profile independently of HIV status or ART regimen, lipocalin-2 could represent a useful marker for HIV- and ART-related adipose tissue dysfunction.

Electronic supplementary material

The online version of this article (10.1186/s12879-017-2925-4) contains supplementary material, which is available to authorized users.

Diagnostic challenges of kidney diseases in HIV-infected patients

INTRODUCTION

Chronic kidney disease (CKD) is a prevalent comorbidity in persons living with HIV infection (PLWH) associated with an increase in cardiovascular morbidity and all-cause mortality. Furthermore, early diagnosis of CKD is difficult in PLWH. Areas covered: We reviewed the main diagnostic tools for CKD in PLWH, and discussed their strengths and limits. We performed a literature search on PubMed to identify reviews and clinical trials dealing with attractive kidney biomarkers of CKD in PLWH, with the following key words: 'HIV AND kidney', 'HIV AND Kidney biomarkers', 'CKD AND Kidney biomarkers'. Expert commentary: Currently, CKD diagnosis is based on the estimation of Glomerular Filtration Rate (GFR), and measurement of proteinuria by urine protein/creatinine ratio (uPCR). These parameters are independent and complementary predictors of outcomes. GFR estimates are lacking in accuracy in PLWH. The best GFR estimate is CKD-EPI study equation. Moreover, low-grade proteinuria is associated with an increased risk of kidney disease progression in PLWH, and guidelines derived from the general population may lack sensitivity. Different biomarkers of kidney diseases like N-acetyl beta glucosaminidase (NAG), Kidney Injury Molecule-1 (KIM-1), and Alpha-1-microglobulin may predict kidney disease progression and mortality in PLWH. Others may help clinicians detect antiretroviral-induced tubulopathy, or predict cardiovascular events. More studies are needed to validate the routine use of these types of biomarkers.

HIV infection rather than concurrent opportunistic infections drives most systemic procoagulant, vascular and damage responses - a prospective cohort study in central Africa

BACKGROUND

HIV infection is accompanied by various systemic host responses, including activation of coagulation and the vascular endothelium. We sought to determine the impact of opportunistic coinfections in a central African setting.

METHODS

This prospective study included 98 HIV-infected individuals in Gabon initiating combination antiretroviral therapy (cART) and followed them up for 6 months. Patients were stratified according to the presence of active tuberculosis (TB; n=19), mucocutaneous opportunistic infection (n=9) or no opportunistic infection (n=70). HIV-uninfected subjects were included as controls (n=32). Plasma concentrations of 14 markers of coagulation, endothelial activation, extracellular matrix formation and tissue damage were measured with a multiplex assay at baseline and months 3 and 6 after cART initiation.

RESULTS

HIV-infected patients showed elevated plasma levels of all biomarkers measured with exception of protein C, which was reduced. Concurrent TB was only associated with elevated concentrations of D-dimer, metallopeptidase inhibitor 1 and Tenascin-C. Mucocutaneous coinfection did not alter HIV-associated responses. Most markers measured declined but remained elevated despite response to cART.

CONCLUSIONS

HIV infection is associated with systemic pro-coagulant, vascular and damage responses. In an ambulatory setting, concurrent opportunistic infections have little if any influence on these responses and normalization is incomplete after response to cART. This suggests that these responses are mainly driven by HIV-associated immune activation and less so by opportunistic infections.