Clinical review: Use of renal replacement therapies in special groups of ICU patients

Acute kidney injury (AKI) in ICU patients is typically associated with other severe conditions that require special attention when renal replacement therapy (RRT) is performed. RRT includes a wide range of techniques, each with specific characteristics and implications for use in ICU patients. In the present review we discuss a wide range of conditions that can occur in ICU patients who have AKI, and the implications this has for RRT. Patients at increased risk for bleeding should be treated without anticoagulation or with regional citrate anticoagulation. In patients who are haemodynamically unstable, continuous therapies are most often employed. These therapies allow slow removal of volume and guarantee a stable blood pH. In patients with cerebral oedema, continuous therapy is recommended in order to prevent decreased cerebral blood flow, which will lead to cerebral ischemia. Continuous therapy will also prevent sudden change in serum osmolality with aggravation of cerebral oedema. Patients with hyponatraemia, as in liver failure or decompensated heart failure, require extra attention because a rapid increase of serum sodium concentration can lead to irreversible brain damage through osmotic myelinolysis. Finally, in patients with severe lactic acidosis, RRT can be used as a bridging therapy, awaiting correction of the underlying cause. Especially in ICU patients who have severe AKI, treatment with RRT requires balancing the pros and cons of different options and modalities. Exact and specific guidelines for RRT in these patients are not available for most clinical situations. In the present article we provide an update on the existing evidence

1014-92 Impaired Microcirculation in Chronic Heart Failure

The microcirculation plays a crucial role in the exchange of oxygen, energy rich substrates and metabolites. The effects on the microcirculation of impaired heart function and disturbed peripheral skin circulation in chronic heart failure (CHF) are unknown. Nailfold capillary morphology and dynamics in CHF were studied in relation to parameters of left ventricular (LV) structure and function. Twenty patients (13 male, 7 female, age 64±2 years) with CHF NYHA class II underwent a capillaroscopic examination at the finger nailfold using a computerised videophotometric system (Capiflow) at rest and after 1 min arterial occlusion. Patients were treated with diuretics, ACE inhibitors and digoxin and mean duration of symptoms was 65±9 months. Study parameters were number, length, and diameter of the capillaries as well as capillary blood velocity (CBV). Further experiments included echocardiography and determination of LV ejection fraction by Tc-scintigraphy. Nailfold capillaries in established CHF are enlarged (afferent diameter 6.6±0.4 μm, efferent diameter 8.2±0.4 μm, ref. resp. <6 and <8 μm) and CBV is dramatically decreased (351±64 μ/s, ref. >600 μm/s at 23°C). The reactive hyperemic response to one minute arterial occlusion is attenuated (peak CBV 879±158 μm/s, ref >2000 μm/s). CBV correlates positively with LV ejection fraction (r=0.61, p=001) and inversely with LV end-diastolic (r=-0.56, P=0.04) and end-systolic (r=-0.69, P=0.01) diameters. The time-to-peak flow (35±5 s, ref. 6–10 s) after one min arterial occlusion is positively related (r=0.68, P<0.05) to the duration of CHF. Our data indicate that microcirculation in chronic heart failure deteriorates in function of the severity and duration of heart failure

Influence of severity of illness on neutrophil gelatinase-associated lipocalin performance as a marker of acute kidney injury : a prospective cohort study of patients with sepsis

Background: The role of neutrophil gelatinase-associated lipocalin (NGAL) as a diagnostic marker for acute kidney injury (AKI) in sepsis is still debated. We hypothesized that in sepsis, the performance of serum(s) and urinary(u) NGAL can be negatively impacted by severity of illness and inflammation, and that both uNGAL and sNGAL levels can be increased regardless of presence of AKI. Methods: One hundred and seven patients with sepsis were included. uNGAL and sNGAL were measured at admission (T0) and 4 hours (T4) and 24 hours later (T24). Transient and intrinsic AKI were respectively defined as AKI according to RIFLE during the first 72 hours that did or did not recover to "no AKI" in the following 72 hours. Patients were classified according to tertiles of CRP and APACHE II score increase. The relationship between sNGAL and uNGAL was assessed by linear regression. Results: Fifty-seven patients developed transient and 22 intrinsic AKI. Prevalence of transient and intrinsic AKI were higher in patients with versus without septic shock (OR (95% CI): 3.3(1.4-8.2)). uNGAL was associated with sNGAL, and this with parallel slopes but different intercepts for AKI (Y = 0.87*X + 314.3, R-2 = 0.31) and no AKI (Y = 0.87*X + 20.1, R-2 = 0.38). At T4, median uNGAL and sNGAL levels were higher in septic patients with versus without shock but this is independent of AKI ((545 ng/mL vs 196 ng/ml for uNGAL and 474 ng/ml vs 287 ng/ml for sNGAL (both P = 0.003)). Both uNGAL and sNGAL levels increased with tertiles of CRP and APACHE II score increase. Conclusions: Serum and uNGAL levels are influenced by severity of illness and inflammation, and this was found to be independent of the presence of AKI. There is a strong correlation between sNGAL and uNGAL levels in patients with sepsis, indicating that increased levels of uNGAL can also be due to overspill from the systemic circulation, blurring the discriminative value of NGAL as a biomarker for AKI in patients with sepsis

Long-term quality of life in critically ill patients with acute kidney injury treated with renal replacement therapy : a matched cohort study

Introduction: Acute kidney injury (AKI) is a common complication in intensive care unit (ICU) patients and is associated with increased morbidity and mortality. We compared long-term outcome and quality of life (QOL) in ICU patients with AKI treated with renal replacement therapy (RRT) with matched non-AKI-RRT patients. Methods: Over 1 year, consecutive adult ICU patients were included in a prospective cohort study. AKI-RRT patients alive at 1 year and 4 years were matched with non-AKI-RRT survivors from the same cohort in a 1: 2 (1 year) and 1: 1 (4 years) ratio based on gender, age, Acute Physiology and Chronic Health Evaluation II score, and admission category. QOL was assessed by the EuroQoL-5D and the Short Form-36 survey before ICU admission and at 3 months, 1 and 4 years after ICU discharge. Results: Of 1953 patients, 121 (6.2 %) had AKI-RRT. AKI-RRT hospital survivors (44.6 %; N = 54) had a 1-year and 4-year survival rate of 87.0 % (N = 47) and 64.8 % (N = 35), respectively. Forty-seven 1-year AKI-RRT patients were matched with 94 1-year non-AKI-RRT patients. Of 35 4-year survivors, three refused further cooperation, three were lost to follow-up, and one had no control. Finally, 28 4-year AKI-RRT patients were matched with 28 non-AKI-RRT patients. During ICU stay, 1-year and 4-year AKI-RRT patients had more organ dysfunction compared to their respective matches (Sequential Organ Failure Assessment scores 7 versus 5, P < 0.001, and 7 versus 4, P < 0.001). Long-term QOL was, however, comparable between both groups but lower than in the general population. QOL decreased at 3 months, improved after 1 and 4 years but remained under baseline level. One and 4 years after ICU discharge, 19.1 % and 28.6 % of AKI-RRT survivors remained RRT-dependent, respectively, and 81.8 % and 71 % of them were willing to undergo ICU admission again if needed. Conclusion: In long-term critically ill AKI-RRT survivors, QOL was comparable to matched long-term critically ill non-AKI-RRT survivors, but lower than in the general population. The majority of AKI-RRT patients wanted to be readmitted to the ICU when needed, despite a higher severity of illness compared to matched non-AKI-RRT patients, and despite the fact that one quarter had persistent dialysis dependency

Identification of putative cancer genes through data integration and comparative genomics between plants and humans

Coordination of cell division with growth and development is essential for the survival of organisms. Mistakes made during replication of genetic material can result in cell death, growth defects, or cancer. Because of the essential role of the molecular machinery that controls DNA replication and mitosis during development, its high degree of conservation among organisms is not surprising. Mammalian cell cycle genes have orthologues in plants, and vice versa. However, besides the many known and characterized proliferation genes, still undiscovered regulatory genes are expected to exist with conserved functions in plants and humans. Starting from genome-wide Arabidopsis thaliana microarray data, an integrative strategy based on coexpression, functional enrichment analysis, and cis-regulatory element annotation was combined with a comparative genomics approach between plants and humans to detect conserved cell cycle genes involved in DNA replication and/or DNA repair. With this systemic strategy, a set of 339 genes was identified as potentially conserved proliferation genes. Experimental analysis confirmed that 20 out of 40 selected genes had an impact on plant cell proliferation; likewise, an evolutionarily conserved role in cell division was corroborated for two human orthologues. Moreover, association analysis integrating Homo sapiens gene expression data with clinical information revealed that, for 45 genes, altered transcript levels and relapse risk clearly correlated. Our results illustrate how a systematic exploration of the A. thaliana genome can contribute to the experimental identification of new cell cycle regulators that might represent novel oncogenes or/and tumor suppressors

Long-term outcome in ICU patients with acute kidney injury treated with renal replacement therapy : a prospective cohort study

Background: In intensive care unit (ICU) patients, acute kidney injury treated with renal replacement therapy (AKI-RRT) is associated with adverse outcomes. The aim of this study was to evaluate variables associated with long-term survival and kidney outcome and to assess the composite endpoint major adverse kidney events (MAKE; defined as death, incomplete kidney recovery, or development of end-stage renal disease treated with RRT) in a cohort of ICU patients with AKI-RRT. Methods: We conducted a single-center, prospective observational study in a 50-bed ICU tertiary care hospital. During the study period from August 2004 through December 2012, all consecutive adult patients with AKI-RRT were included. Data were prospectively recorded during the patients' hospital stay and were retrieved from the hospital databases. Data on long-term follow-up were gathered during follow-up consultation or, in the absence of this, by consulting the general physician. Results: AKI-RRT was reported in 1292 of 23,665 first ICU admissions (5.5 %). Mortality increased from 59.7 % at hospital discharge to 72.1 % at 3 years. A Cox proportional hazards model demonstrated an association of increasing age, severity of illness, and continuous RRT with long-term mortality. Among hospital survivors with reference creatinine measurements, 1-year renal recovery was complete in 48.4 % and incomplete in 32.6 %. Dialysis dependence was reported in 19.0 % and was associated with age, diabetes, chronic kidney disease (CKD), and oliguria at the time of initiation of RRT. MAKE increased from 83.1 % at hospital discharge to 93. 7 % at 3 years. Multivariate regression analysis showed no association of classical determinants of outcome (preexisting CKD, timing of initiation of RRT, and RRT modality) with MAKE at 1 year. Conclusions: Our study demonstrates poor long-term survival after AKI-RRT that was determined mainly by severity of illness and RRT modality at initiation of RRT. Renal recovery is limited, especially in patients with acute-on-chronic kidney disease, making nephrological follow-up imperative. MAKE is associated mainly with variables determining mortality

Minimal information for studies of extracellular vesicles 2018 (MISEV2018):a position statement of the International Society for Extracellular Vesicles and update of the MISEV2014 guidelines

The last decade has seen a sharp increase in the number of scientific publications describing physiological and pathological functions of extracellular vesicles (EVs), a collective term covering various subtypes of cell-released, membranous structures, called exosomes, microvesicles, microparticles, ectosomes, oncosomes, apoptotic bodies, and many other names. However, specific issues arise when working with these entities, whose size and amount often make them difficult to obtain as relatively pure preparations, and to characterize properly. The International Society for Extracellular Vesicles (ISEV) proposed Minimal Information for Studies of Extracellular Vesicles (“MISEV”) guidelines for the field in 2014. We now update these “MISEV2014” guidelines based on evolution of the collective knowledge in the last four years. An important point to consider is that ascribing a specific function to EVs in general, or to subtypes of EVs, requires reporting of specific information beyond mere description of function in a crude, potentially contaminated, and heterogeneous preparation. For example, claims that exosomes are endowed with exquisite and specific activities remain difficult to support experimentally, given our still limited knowledge of their specific molecular machineries of biogenesis and release, as compared with other biophysically similar EVs. The MISEV2018 guidelines include tables and outlines of suggested protocols and steps to follow to document specific EV-associated functional activities. Finally, a checklist is provided with summaries of key points