Aging and the impact of global DNA methylation, telomere shortening, and total oxidative status on sarcopenia and frailty syndrome.

Aging is a biological event that influences many organs and systems. Both sarcopenia and frailty syndrome refer to geriatric conditions with overlapping phenotypes. Many mechanisms are involved in the aging process such as DNA methylation telomeres which are susceptible to oxidative stress, and inflammations which result in telomere shortening, leading to chromosomal instability. The study aimed to determine the associations between these processes, frailty and sarcopenia syndrome. Global DNA methylation was analyzed using the ELISA method. Telomere length was analyzed using qPCR. Total oxidative status (TOS) was analyzed using a colorimetric method. The present study revealed that the main factor affecting methylation, telomeres length and level of total oxidant stress was age.

Acute Kidney Injury Biomarkers Predict an Increase in Serum Milrinone Concentration Earlier Than Serum Creatinine-Defined Acute Kidney Injury in Infants After Cardiac Surgery.

BACKGROUND: Milrinone, an inotropic agent used ubiquitously in children after cardiac surgery, accumulates in acute kidney injury (AKI). We assessed if urinary AKI biomarkers are predictive of an increase in milrinone concentrations in infants after cardiac surgery. METHODS: Multicenter prospective pilot study of infants undergoing cardiac surgery. Urinary AKI biomarkers were measured in the urine at specific time intervals after cardiopulmonary bypass initiation. AKI was defined using the Kidney Disease: Improving Global Outcomes serum creatinine criteria. Serum milrinone concentrations were measured at specific intervals after drug initiation, dose changes, and termination. Excessive milrinone activity was defined as a 20% increase in serum concentration between 6 and 36 hours after initiation. The temporal relationship between urinary AKI biomarker concentrations and a 20% increase in milrinone concentration was assessed. RESULTS: AKI occurred in 31 (33%) of infants. Milrinone clearance was lower in patients with AKI (4.2 versus 5.6 L/h/70 kg; P = 0.02). Excessive milrinone activity was associated with development of serum creatinine-defined AKI [odds ratio (OR) 3.0; 95% confidence interval (CI), 1.21-7.39; P = 0.02]. Both tissue inhibitor metalloproteinase type 2 and insulin-like growth factor-binding protein type 7 (TIMP-2*IGFBP-7) ≥0.78 at 12 hours (OR 2.72; 95% CI, 1.01-7.38; P = 0.04) and kidney injury molecule 1 (KIM-1) ≥529.57 at 24 hours (OR 2.76; 95% CI, 1.06-7.17; P = 0.04) predicted excessive milrinone activity before a diagnosis of AKI. CONCLUSIONS: In this pilot study, urine TIMP-2*IGFBP-7 and KIM-1 were predictive of AKI and excessive milrinone activity. Future studies that include a pharmacodynamics assessment of patient hemodynamics, excessive milrinone activity, and AKI biomarker concentrations may be warranted to integrate this concept into clinical practice.

Kinetics of the cell cycle arrest biomarkers (TIMP-2*IGFBP-7) for prediction of acute kidney injury in infants after cardiac surgery.

BACKGROUND: Tissue inhibitor metalloproteinase-2 (TIMP-2) and insulin-like growth factor binding protein-7 (IGFBP-7) are cell-cycle arrest biomarkers that have been shown to be predictive of acute kidney injury (AKI) in critically ill adults. AKI affects a large proportion (40%) of children following cardiac surgery. The aim of this study was to describe the kinetics of TIMP-2*IGFBP-7 and test its ability to predict AKI in infants following cardiac surgery. METHODS: A multicenter prospective study was performed in infants undergoing cardiac surgery with cardiopulmonary bypass (CPB) from October 2013 to January 2015. Urine samples were obtained at baseline and at 2, 6, 12, 24, 48 and 72 h after CPB initiation. TIMP-2*IGFBP-7 concentration was measured in urine samples using the Astute 140® meter to determine a risk score for AKI. This risk score is the product of TIMP-2 (ng/mL) and IGFBP-7 (ng/mL) divided by 1000. RESULTS: A total of 94 infants with a mean age of 154.2 ± 85.7 days were enrolled in the study, of whom 31 (33%) subsequently developed AKI. The mean time to AKI diagnosis was 25 ± 7 h after CPB initiation. The concentration of TIMP-2*IGFBP-7 was significantly higher in patients with AKI at 12 h after CPB initiation relative to baseline (p = 0.006). At 12 h after CPB initiation patients with a TIMP-2*IGFBP-7 concentration of ≥0.78 had a threefold higher odds of developing AKI than those with a TIMP-2*IGFBP-7 concentration of < 0.78 (95% confidence interval 1.47-6.11, p = 0.001). CONCLUSION: These results demonstration that TIMP-2*IGFBP-7 concentration can be used in infants to predict subsequent serum creatinine-defined AKI following CPB.