Acute kidney injury in Turkey: epidemiological characteristics, etiology, clinical course, and prognosis.

BACKGROUND: This study aimed to evaluate the etiologies, comorbidities, and outcomes of acute kidney injury (AKI) in Turkey and determine any potential differences among different geographical parts of the country. METHODS: This prospective observational study was conducted by the Acute Kidney Injury Working Group of the Turkish Society of Nephrology. Demographical and clinical data of patients with AKI at the time of diagnosis and at the 1st week and 1st, 3rd, and 6th months of diagnosis were evaluated to determine patient and renal survival and factors associated with patient prognosis. RESULTS: A total of 776 patients were included (54.7% male, median age: 67 years). Prerenal etiologies, including dehydration, heart failure, and sepsis, were more frequent than other etiologies. 58.9% of the patients had at least one renal etiology, with nephrotoxic agent exposure as the most common etiology. The etiologic factors were mostly similar throughout the country. 33.6% of the patients needed kidney replacement therapy. At the 6th month of diagnosis, 29.5% of the patients had complete recovery; 34.1% had partial recovery; 9.5% developed end-stage kidney disease; and 24.1% died. The mortality rate was higher in the patients from the Eastern Anatolian region; those admitted to the intensive care unit; those with prerenal, renal, and postrenal etiologies together, stage 3 AKI, sepsis, cirrhosis, heart failure, and malignancy; those who need kidney replacement therapy; and those without chronic kidney disease than in the other patients. CONCLUSION: Physicians managing patients with AKI should be alert against dehydration, heart failure, sepsis, and nephrotoxic agent exposure. Understanding the characteristics and outcomes of patients with AKI in their countries would help prevent AKI and improve treatment strategies.

Neutrophil gelatinase-associated lipocalin is a better biomarker than cystatin C for the prediction of imminent acute kidney injury in critically ill patients.

Aims The prevention of acute kidney injury can be lifesaving for the intensive care unit patients. However, conventional methods are not sufficient for the prediction of the risk of future acute kidney injury. In this study, the promising biomarker, neutrophil gelatinase-associated lipocalin, was compared with cystatin C as an indicator for the risk of future acute kidney injury. Methods One hundred and eighty-three adult patients without chronic kidney disease or renal replacement therapy were included in this study. The plasma and urine concentrations of neutrophil gelatinase-associated lipocalin and cystatin C were assessed on the second day after intensive care unit admission and were followed for seven days to monitor the development of acute kidney injury. Acute kidney injury diagnosis was based on the risk, injury, failure, loss, end-stage renal failure criteria. Results Thirty-four per cent of the patients had acute kidney injury; 17 patients who did not fulfil criteria at the beginning, developed acute kidney injury from days 3 to 7 after admission. The mean serum creatinine on admission did not significantly differ between this and control groups (0.72 ± 0.20 and 0.83 ± 0.21; P = 0.060); however, the serum and urinary neutrophil gelatinase-associated lipocalin concentrations on the second day were significantly different (median: 75.69 [54.18-91.18] and 123.68 [90.89-166.31], P = 0.001; and median: 17.60 [8.56-34.04] and 61.37 [24.59-96.63], P = 0.001). Notably, the 48-h serum cystatin C concentration did not differ. Conclusion Neutrophil gelatinase-associated lipocalin concentrations in the urine and serum on the second day of intensive care unit admission could be used to predict the development of acute kidney injury in the following three to seven days in the intensive care unit; however, the cystatin C concentration did not have predictive value.

Neutrophil gelatinase-associated lipocalin levels during the first 48 hours of intensive care may indicate upcoming acute kidney injury.

PURPOSE: The recognition of acute kidney injury (AKI) as early as possible is important in the intensive care unit. This study proposes that serum and urine levels of neutrophil gelatinase-associated lipocalin (NGAL) may be used for this purpose. METHODS: One hundred and seven critically ill adult patients with no previous renal failure were included. NGAL levels were measured during the first 48 hours after admission; NGAL levels were followed for 7 days and classified based on Risk, Injury, Failure, Loss, and End-Stage Renal Failure criteria. RESULTS: The AKI incidence was 35.5%, and serum NGAL (sNGAL) and urinary NGAL (uNGAL) levels were higher in the AKI group. The area under the receiver operating characteristic curve was 0.76 (P<.001) for sNGAL and 0.75 (P<.001) for uNGAL. Seventy-one percent of AKI cases were observed within 48 hours, with 11 additional cases in the ensuing 7 days. The mean serum creatinine levels in the 11 patients were not different from non-AKI levels (P=.197), but the NGAL values were different, and the area under the receiver operating characteristic curve for sNGAL uNGAL was 1.00 (P=.014) and 0.93 (P=.02), respectively. CONCLUSIONS: Most AKI cases were diagnosed within the first 48 hours after admission, and NGAL was useful for predicting upcoming AKI.

Comparative Proteome Analysis of hAT-MSCs Isolated from Chronic Renal Failure Patients with Differences in Their Bone Turnover Status.

The relationship between the stem cells and the bone turnover in uremic bone disease due to chronic renal failure (CRF) is not described. The aim of this study was to investigate the effect of bone turnover status on stem cell properties. To search for the presence of such link and shed some light on stem-cell relevant mechanisms of bone turnover, we carried out a study with mesenchymal stem cells. Tissue biopsies were taken from the abdominal subcutaneous adipose tissue of a CRF patient with secondary hyperparathyroidism with the high turnover bone disease. This patient underwent parathyroidectomy operation (PTX) and another sample was taken from this patient after PTX. A CRF patient with adynamic bone disease with low turnover and a healthy control were also included. Mesenchymal stem cells isolated from the subjects were analyzed using proteomic and molecular approaches. Except ALP activity, the bone turnover status did not affect common stem cell properties. However, detailed proteome analysis revealed the presence of regulated protein spots. A total of 32 protein spots were identified following 2D gel electrophoresis and MALDI-TOF/TOF analyzes. The identified proteins were classified into seven distinct groups and their potential relationship to bone turnover were discussed. Distinct protein expression patterns emerged in relation to the bone turnover status indicate a possible link between the stem cells and bone turnover in uremic bone disease due to CRF.