Acute Tubular Injury is Associated With Severe Traumatic Brain Injury: in Vitro Study on Human Tubular Epithelial Cells

Federica Civiletti,Barbara Assenzio,Vito Fanelli,Fulvia Giaretta,Vito Marco Ranieri,Vincenzo Cantaluppi,Luciana Mascia,Davide Medica,Ilaria Deambrosis,Anna Teresa Mazzeo

doi:10.1038/s41598-019-42147-4

Abstract

Acute kidney injury following traumatic brain injury is associated with poor outcome. We investigated in vitro the effects of plasma of brain injured patients with acute tubular kidney injury on kidney tubular epithelial cell function. we performed a prospective observational clinical study in ICU in a trauma centre of the University hospital in Italy including twenty-three ICU patients with traumatic brain injury consecutively enrolled. Demographic data were recorded on admission: age 39 ± 19, Glasgow Coma Score 5 (3–8). Neutrophil Gelatinase-Associated Lipocalin and inflammatory mediators were measured in plasma on admission and after 24, 48 and 72 hours; urine were collected for immunoelectrophoresis having healthy volunteers as controls. Human renal proximal tubular epithelial cells were stimulated with patients or controls plasma. Adhesion of freshly isolated human neutrophils and trans-epithelial electrical resistance were assessed; cell viability (XTT assay), apoptosis (TUNEL staining), Neutrophil Gelatinase-Associated Lipocalin and Megalin expression (quantitative real-time PCR) were measured. All patients with normal serum creatinine showed increased plasmatic Neutrophil Gelatinase-Associated Lipocalin and increased urinary Retinol Binding Protein and α1-microglobulin. Neutrophil Gelatinase-Associated Lipocalin was significantly correlated with both inflammatory mediators and markers of tubular damage. Patient’ plasma incubated with tubular cells significantly increased adhesion of neutrophils, reduced trans-epithelial electrical resistance, exerted a cytotoxic effect and triggered apoptosis and down-regulated the endocytic receptor Megalin compared to control. Plasma of brain injured patients with increased markers of subclinical acute kidney induced a pro-inflammatory phenotype, cellular dysfunction and apoptotic death in tubular epithelial cells.

Highlights

In patients with traumatic brain injury (TBI), outcome is highly influenced by non-neurological complications[1,2,3] including acute kidney injury (AKI)[4]
No patients developed AKI or were considered at risk according with RIFLE criteria: on T48 Neutrophil Gelatinase-Associated Lipocalin (NGAL) was elevated in 40%, retinol binding protein (RBP) in all patients, α1-microglobulin in 10% and albumin in 90% of the patients compared to controls (Table 2)
Plasma NGAL and low molecular weight proteinuria were significantly increased compared to controls even if biomarkers currently used for diagnosis and risk of AKI (i.e. serum creatinine and estimated glomerular filtration rate)[26,27,28,29,30,31] were not altered

Summary

Introduction

In patients with traumatic brain injury (TBI), outcome is highly influenced by non-neurological complications[1,2,3] including acute kidney injury (AKI)[4]. Recent studies reported an incidence of AKI equal to 8–20% in TBI patients[5,6] using serum creatinine increase and urine output decrease as criteria for AKI. We hypothesized that following TBI, tubular cells represent a target of the inflammatory reaction leading to a consequent cellular dysfunction. To test this hypothesis, we performed a prospective observational clinical study to identify severe TBI patients with subclinical AKI and increased inflammatory reaction. In the in vitro study, we exposed human kidney-derived tubular epithelial cells to plasma of TBI patients with evidence of subclinical AKI

Methods

Results

Discussion

Conclusion