Augmentation of Urinary Lactoferrin Enhances Host Innate Immune Clearance of Uropathogenic Escherichia coli.

Urinary tract infection (UTI) is a prominent global health care burden. Although UTI is readily treated with antibiotics in healthy adults, complicated cases in immune-compromised individuals and the emerging antibiotic resistance of several uropathogens have accelerated the need for new treatment strategies. Here, we surveyed the composition of urinary exosomes in a mouse model of uropathgenic Escherichia coli (UPEC) UTI to identify specific urinary tract defense constituents for therapeutic development. We found an enrichment of the iron-binding glycoprotein lactoferrin in the urinary exosomes of infected mice. In subsequent in vitro studies, we identified human bladder epithelial cells as a source of lactoferrin during UPEC infection. We further established that exogenous treatment with human lactoferrin (hLf) reduces UPEC epithelial adherence and enhances neutrophil antimicrobial functions including bacterial killing and extracellular trap production. Notably, a single intravesicular dose of hLf drastically reduced bladder bacterial burden and neutrophil infiltration in our murine UTI model. We propose that lactoferrin is an important modulator of innate immune responses in the urinary tract and has potential application in novel therapeutic design for UTI.

Biomarkers of Renal Injury in Cirrhosis: Association with Acute Kidney Injury and Recovery after Liver Transplantation.

BACKGROUND: To define urine or serum biomarkers in predicting renal function recovery after liver transplantation (LT). METHODS: Adults listed for LT (February 2011-July 2014) and with modified diet for renal disease-6 (MDRD-6) <60 mL/min provided urine/blood samples at baseline and serially until LT for biomarkers in serum (pg/mL) and urine (pg/mg creatinine). RESULTS: Of 271 LT listed patients (mean age 57 years, 63% males, median listing MELD 17.5), 1 year acute kidney injury (AKI) probability was 49%, with odds of 1.3-, 3.0-, 4.6-, and 8.5-fold times for listing MELD 16-20, 21-25, 26-30, and >30, compared to MELD <16. Thirty-seven people died over 1 year from the time of listing, with twofold increased odds with AKI. Among 67 patients with MDRD <60, only urinary epidermal growth factor was different comparing AKI (increase in serum creatinine ≥0.3 mg/dL from baseline within past 3 months) vs. no AKI (2,254 vs. 4,253, p = 0.003). Differences between acute tubular necrosis (ATN) and hepatorenal syndrome could not be ascertained for a small sample of 3 patients with ATN. Analyzing 15 of 43 receiving LT and MDRD-6 <30 prior to LT, biomarkers were not different comparing 5 patients recovering renal function (MDRD-6 >50 mL/min) at 6 months vs. 10 without recovery. CONCLUSIONS: AKI is common among LT listed patients, with a negative impact on transplant-free survival. Serum and urine biomarkers are not associated with the recovery of renal function after LT. Multicenter studies are suggested to (a) develop strategies to reduce the development of AKI and (b) derive novel biomarkers for use in accurately predicting renal recovery after LT.

Rationale and Design of the Genetic Contribution to Drug Induced Renal Injury (DIRECT) Study.

INTRODUCTION: Nephrotoxicity from drugs accounts for 18% to 27% of cases of acute kidney injury. Determining a genetic predisposition may potentially be important in minimizing risk. The aims of this study are as follows: to determine whether a genetic predisposition exists for the development of drug-induced kidney disease (DIKD), using genome-wide association and whole-genome sequencing studies; to describe the frequency, course, risk factors, resolution and outcomes of DIKD cases; to investigate the role of ethnic/racial variability in the genetics of DIKD; and to explore the use of different tools establishing causality of DIKD. METHODS: A total of 800 patients will be enrolled worldwide and blood samples for DNA collected. Data on the patient risk factors, vital signs, laboratory parameters, drug exposure, and DIKD course will be recorded. A panel of nephrologists will adjudicate all cases. Genome-wide association studies will be conducted using population controls matched on biogeographic ancestry to determine whether there is a genetic predisposition to DIKD. The primary endpoint is the identification of specific drug-related polymorphisms associated with DIKD. Secondary endpoints include the following: frequency of DIKD by causal drug and drug combinations; DIKD genetic variability; exploration of causality assessment tools; risk factor identification; description of the course of DIKD, including mortality and dialysis dependency at hospital discharge and 28 and 90 days post-event. RESULTS: Data are currently being analyzed. Results are pending. DISCUSSION: The Genetic Contribution to Drug Induced Renal Injury (DIRECT) study will be the first observational cohort study to investigate the genetic determinants of DIKD. If the trial is positive, its findings will potentially translate into safer patient outcomes, by genotypic individualization of therapy and minimization of harm.

Profiling of human mesangial cell subproteomes reveals a role for calmodulin in glucose uptake.

Proteomics combined with cell fractionation was used to identify proteins regulated by high glucose (HG) in human mesangial cells (HMC). Total membrane and cytosolic fraction proteins derived from HMC after 7 days of HG exposure were resolved by a two-dimensional gel electrophoresis approach. DeCyder software was used to analyze the HG-induced protein spot dysregulation. In the membrane subproteome, of the 92 spots that were matched across all gels, HG induced significant downregulation of only 4 protein spots. The dysregulated spots from the membrane subproteome included binding protein (BiP), calreticulin precursor protein, a 63-kDa transmembrane protein from a ER/Golgi intermediate, and beta-subunit of collagen proline 4-hydroxylase. In the cytosolic subproteome, of the 122 spots that were matched across all gels, HG induced downregulation of 3 protein spots and upregulation of 2 protein spots significantly. Enolase 1, annexin VI, and gamma(2)-actin were decreased, whereas heat shock protein-70 kDa and calmodulin (CaM) were increased. Further confocal microscopy and Western immunoblotting of mesangial cells validated the increase in CaM. Immunoblotting of diabetic mouse and rat kidneys exhibited a marked increase in CaM at both early and late stages of diabetes, reflecting the potential physiological relevance of CaM upregulation. CaM-specific inhibitors blocked glucose transport stimulated by transforming growth factor-beta and insulin in mesangial cells. In conclusion, using a combination of cell fractionation and protein expression profiling, we identified a cohort of HG-dysregulated proteins in the HMC and identified a critical and as yet unrecognized role for CaM in glucose transport in mesangial cells.