Trimethlyamine-N-oxide (TMAO) was recently identified as a promoter of atherosclerosis. Patients with CKD exhibit accelerated development of atherosclerosis; however, no studies have explored the relationship between TMAO and atherosclerosis formation in this group. This study measured serum concentrations and urinary excretion of TMAO in a CKD cohort (n=104), identified the effect of renal transplant on serum TMAO concentration in a subset of these patients (n=6), and explored the cross-sectional relationship between serum TMAO and coronary atherosclerosis burden in a separate CKD cohort (n=220) undergoing coronary angiography. Additional exploratory analyses examined the relationship between baseline serum TMAO and long-term survival after coronary angiography. Serum TMAO concentrations demonstrated a strong inverse association with eGFR (r 2 =0.31, P,0.001). TMAO concentrations were markedly higher in patients receiving dialysis (median [interquartile range], 94.4 mM [54.8-133.0 mM] for dialysis-dependent patients versus 3.3 mM [3.1-6.0 mM] for healthy controls; P,0.001); whereas renal transplantation resulted in substantial reductions in TMAO concentrations (median [min-max] 71.2 mM [29.2-189.7 mM] pretransplant versus 11.4 mM [8.9-20.2 mM] posttransplant; P=0.03). TMAO concentration was an independent predictor for coronary atherosclerosis burden (P=0.02) and predicted long-term mortality independent of traditional cardiac risk factors (hazard ratio, 1.26 per 10 mM increment in TMAO concentration; 95% confidence interval, 1.13 to 1.40; P,0.001). In conclusion, serum TMAO concentrations substantially increase with decrements in kidney function, and this effect is reversed by renal transplantation. Increased TMAO concentrations correlate with coronary atherosclerosis burden and may associate with long-term mortality in patients with CKD undergoing coronary angiography. Patients with CKD have a high prevalence of cardiovascular comorbidities, which primarily contributes to the exceedingly high mortality in this group. 1,2 For example, the 5-year survival for ESRD patients receiving dialysis is approximately 35%, with .50% of the mortality in this group resulting directly from cardiovascular causes. 1 It is well established that CKD patients exhibit a disproportionate burden of atherosclerosis as compared with individuals having normal kidney function. [2][3][4][5] Furthermore, a higher prevalence of traditional risk factors for the development of atherosclerosis, such as hypertension, diabetes and hyperlipidemia, only partially accounts for the accelerated atherosclerosis in CKD patients, leading to the hypothesis that unique risk factors must be present in this population. 6,7

Background-Kidney disease alters the pharmacokinetic disposition of many medications, requiring dosage adjustment to maintain therapeutic serum concentrations. The Cockcroft-Gault equation is used for pharmacokinetic studies and drug dosage adjustments, but the MDRD Study equation is more accurate and more often reported by clinical laboratories than the Cockcroft-Gault equation.

Acute kidney injury (AKI) is a devastating complication commonly occurring in the critically ill population with devastating short- and long-term consequences. Despite standardization of the definition and staging of AKI, early recognition remains challenging given that serum creatinine (Scr) is a marker—albeit imperfect—of kidney function and not kidney injury. Furthermore, the delay in rise of Scr after loss of glomerular filtration also prevents timely detection of decreased kidney function in patients with AKI. Over the past decade, numerous clinical investigations have evaluated the utility of several biomarkers in the early diagnosis and risk stratification of AKI. In 2014, the US Food and Drug Administration (FDA) approved the marketing of a test based on the combination of the urine concentrations of tissue inhibitor of metalloproteinase 2 and insulin-like growth factor binding protein 7 ([TIMP-2]x[IGFBP7]) to determine if certain critically ill patients are at risk of developing moderate to severe AKI. The optimal role of this biomarker in diagnosis, management, and prognosis of AKI in different clinical settings requires further clarification. In this perspective, we summarize the biological actions of these two cell-cycle arrest biomarkers, and present important considerations regarding the clinical application, interpretation, and limitations of this novel test for the early detection AKI.

on behalf of the EXTRIP Workgroup Abstract The Extracorporeal Treatments in Poisoning Workgroup was created to provide evidence-based recommendations on the use of extracorporeal treatments in poisoning. Here, the EXTRIP workgroup presents its recommendations for lithium poisoning. After a systematic literature search, clinical and toxicokinetic data were extracted and summarized following a predetermined format. The entire workgroup voted through a two-round modified Delphi method to reach a consensus on voting statements. A RAND/UCLA Appropriateness Method was used to quantify disagreement, and anonymous votes were compiled and discussed in person. A second vote was conducted to determine the final workgroup recommendations. In total, 166 articles met inclusion criteria, which were mostly case reports, yielding a very low quality of evidence for all recommendations. A total of 418 patients were reviewed, 228 of which allowed extraction of patient-level data. The workgroup concluded that lithium is dialyzable (Level of evidence=A) and made the following recommendations: Extracorporeal treatment is recommended in severe lithium poisoning (1D).

Our recent studies have shown that chronic kidney disease (CKD) affects the pharmacokinetics (PKs) of cytochrome P450 (CYP)2D6‐metabolized drugs, whereas effects were less evident on CYP3A4/5. Therefore, the effect of CKD on the disposition of CYP1A2‐metabolized, CYP2C8‐metabolized, CYP2C9‐metabolized, CYP2C19‐metabolized, and organic anion‐transporting polypeptide (OATP)‐transported drugs was investigated. We identified dedicated CKD studies with 6, 5, 6, 4, and 12 “model” substrates for CYP1A2, CYP2C8, CYP2C9, CYP2C19, and OATP, respectively. Our analyses suggest that clearance of OATP substrates decreases as kidney function declines. Similar trends were seen for CYP2C8; but overlap between some CYP2C8 and OATP substrates highlights that their interplay needs further investigation. In contrast, the effect of CKD on CYP1A2, CYP2C9, and CYP2C19 was variable and modest compared to CYP2C8 and OATP. This improved understanding of elimination‐pathway‐dependency in CKD is important to inform the need and conduct of PK studies in these patients for nonrenally eliminated drugs.