Unique features of albumin: a brief review

Albumin adjuvant therapy for acute ischemic stroke with large vessel occlusion (AMASS-LVO): rationale, design, and protocol for a phase 1, open-label, clinical trial

BACKGROUND

Acute ischemic stroke (AIS) is an acute brain injury caused by sudden occlusion of a blood vessel. Endovascular therapy is the most effective way to restore blood flow. However, despite the restoration of blood flow in some patients, their clinical prognosis often remains unsatisfactory. Albumin has shown neuroprotective effects in animal models of AIS. Therefore, this study aims to evaluate the safety, feasibility, and efficacy of local arterial infusions of 20% human serum albumin solution as an adjuvant therapy after endovascular therapy in patients with AIS.

METHODS

This study is a prospective, therapeutic exploratory, non-randomized, open-label, phase 1 clinical trial testing the use of 20% human serum albumin solution injected via the artery immediately after successful reperfusion in patients with AIS. The study is divided into two stages. In the first stage, a single-dose-finding will explore the maximum safe dose according to the 3 + 3 dose escalation principle;, with the maximum dose being 0.60 g/kg. After recanalizing the occluded blood vessel, human serum albumin solution will be injected into the internal carotid artery region through a guiding catheter for 30 min. The second stage involves an albumin adjuvant therapy cohort (AT) and an endovascular treatment lonely cohort (ET). The AT cohort will encompass at least 15 additional participants to complete safety trials at the maximum safe dose determined in the first stage. The ET cohort will include well-matched patients receiving endovascular therapy alone, derived from a contemporaneous prospective registry, who will be excluded from having cardiopulmonary disorders and from receiving any neuroprotective therapy. The primary outcome of this study will be symptomatic intracranial hemorrhage. Efficacy outcomes will include the proportion of patients with the progression of cerebral infarction volume, a modified Rankin Scale of 0-2 on day 90 after randomization. An exploratory secondary outcome will be the analysis of thromboinflammatory and neuroprotective molecule profiles.

CONCLUSION

This pilot trial aims to explore the safety and efficacy of arterial infusion of an albumin solution after occlusive vessel opening in AIS. The results will provide data parameters for subsequent tests on the arterial infusion of albumin solutions.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, NCT05953623.

HSA over BSA: Selective detection of Human Serum Albumin via a naphtho [2,1-b] furan-based system

Human serum albumin (HSA) is an important biomarker that can be used for the early diagnosis of many diseases. In this work, a TICT probe bearing fused naphtho-furan scaffold (NPNF) was developed and employed in the selective turn-on sensing of HSA. The probe's selectivity towards HSA was observed using steady-state fluorescence experiments, with limit of quantitation in micromolar levels. NPNF's capability to exclusively detect HSA over BSA was further studied/rationalized using anisotropy and time-resolved studies. Molecular docking was used to shed light on the location of NPNF in the subdomain IB of HSA. The practical application of the probe was also demonstrated by the detection of HSA in urine and the HSA-assisted detection of cerium.

In silico identification of molecular mechanisms for stroke risk caused by heavy metals and their mixtures: sponges and drugs involved

This study used various approaches and databases to evaluate the molecular processes and identify miRNA sponges and drugs associated with the development of stroke caused by heavy metals and their combinations. We found that the genes ALB (albumin), IL1B (Interleukin-1β), F2 (coagulation factor II), APOA1 (apolipoprotein A1), IL6 (Interleukin 6), and NOS2 (nitric oxide synthase 2) were linked to the development of strokes by 18 chemicals and a combination of cadmium, copper, and lead. These results may point to the significance of detoxification and neuroinflammation in stroke as well as the potential for targeting these genes in future stroke therapies. ALB and IL1B were the most common and significant genes. The "selenium micronutrient network," "vitamin B12 metabolism," and "folate metabolism" were shown to be the most significant pathways connected to the risk of stroke brought on by combined heavy metals. The two main cellular elements that may increase the risk of stroke caused by heavy metals were discovered to be "blood microparticle" and "endoplasmic reticulum lumen." We also observed an important chromosome (chr7p15.3), two transcription factors (NFKB2 [nuclear factor kappa B subunit 2] and NR1I2 [nuclear receptor subfamily 1 group, member 2]), and four microRNAs (hsa-miR-26a-5p, hsa-miR-9-5p, hsa-miR-124-3p, and hsa-miR-155-5p) associated with stroke caused by combined heavy metals. Additionally, for these miRNAs, we created and examined in silico microRNA sponge sequences. Triflusal and andrographolide have been identified as potential treatments for heavy metal-induced stroke. Taken together, heavy metals may be a significant contributor to the pathophysiology of stroke, but further investigation into the precise molecular pathways implicated in stroke pathophysiology is required to corroborate these findings.

Spectroscopic, molecular docking and dynamic simulation studies of binding between the new anticancer agent olmutinib and human serum albumin

In this study, the interaction between human serum albumin (HSA), which is the key bio-distributor of exogenous and endogenous compounds in the human bloodstream, and HM61713 (Olmutinib; OMB), which is used as an anticancer drug, is examined by multiple spectroscopic techniques (steady-state fluorescence, UV spectrophotometry, synchronous, and 3 D fluorescence) combined with molecular docking and molecular dynamic simulation investigations. The fluorescence results clearly demonstrated quenching in HSA fluorescence in the existence of OMB indicating the formation of complex and have also shown that the interaction is static. Fluorescence spectroscopy was used to obtain the binding constant values that revealed a strong interaction between the HSA and OMB at 298 K with a binding constant of 7.39x10⁴ M^-1 suggesting strong interaction. OMB binds to HSA at site I (IIA). Electrostatic forces and H-bonding were the main binding forces of main bonding between HSA and OMB as revealed by docking and thermodynamic results.Communicated by Ramaswamy H. Sarma.

Prognostic Value of Serum Albumin Level in Critically Ill Patients: Observational Data From Large Intensive Care Unit Databases

Background

Decreased serum albumin level (SAL) is associated with adverse clinical outcomes. We designed the present study to further assess the prognostic value of SAL in critically ill patients based on data from large intensive care unit (ICU) databases.

Methods

This retrospective cohort study recruited 18,353 patients from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database. Restricted cubic splines (RCS) were performed to visualize the association of SAL at admission with ICU and hospital mortalities. The prognostic value of SAL was analyzed using logistic regression models and receiver operating characteristic (ROC) curves in overall patients and subgroups.

Results

Restricted cubic splines revealed rapid increasing risks in ICU and hospital mortalities when SAL declined to below 30 g/l. Patients with SAL <30 g/l (n = 6,069) had higher ICU (13.7% vs. 6.4%, p < 0.001) and hospital (23.9% vs. 10.7%, p < 0.001) mortalities than those with SAL ≥30 g/l. Multivariable logistic regression model revealed that SAL <30 g/l independently correlated with higher risks of both ICU (odds ratio [OR]: 1.20, 95% confidence interval [CI]: 1.07–1.36) and hospital (OR: 1.51, 95% CI: 1.37–1.66) mortalities. However, the association diminished in patients with cirrhosis (OR: 1.16, 95% CI: 0.91–1.49 for ICU mortality; OR: 1.21, 95% CI: 1.00–1.48 for hospital mortality). ROC curves revealed a poor performance of SAL in predicting mortalities, both in overall patients and in those with cirrhosis.

Conclusions

Decreased SAL is associated with increased risk of mortality. However, it possesses low sensitivity and specificity for outcome prediction in critically ill patients, especially in those with cirrhosis.

A Comparison of the Genotoxic Effects of Gold Nanoparticles Functionalized with Seven Different Ligands in Cultured Human Hepatocellular Carcinoma Cells

Gold nanoparticles (GNPs) have shown great potential in diagnostic and therapeutic applications in diseases, such as cancer. Despite GNP versatility, there is conflicting data regarding the toxicity of their overall functionalization chemistry for improved biocompatibility. This study aimed to determine the possible genotoxic effects of functionalized GNPs in Human hepatocellular carcinoma (HepG2) cells. GNPs were synthesized and biofunctionalized with seven common molecules used for biomedical applications. These ligands were bovine serum albumin (BSA), poly(sodium 4-styrene sulfonate) (PSSNA), trisodium citrate (citrate), mercaptoundecanoic acid (MUA), glutathione (GSH), polyvinylpyrrolidone (PVP), and polyethylene glycol (PEG). Before in vitro genotoxicity assessment, inductively coupled plasma mass spectrometry was used to determine GNP cellular internalization quantitatively, followed by cell-based assays; WST-1 to find IC 30 and ApoPercentage for apoptotic induction time-points. The effect of the GNPs on cell growth in real-time was determined by using xCELLigence, followed by a comet assay for genotoxicity determination. The HepG2 cells experienced genotoxicity for all GNP ligands; however, they were able to initiate repair mechanisms and recover DNA damage, except for two functionalization chemistries.

Albumin Reduces Oxidative Stress and Neuronal Apoptosis via the ERK/Nrf2/HO-1 Pathway after Intracerebral Hemorrhage in Rats

BACKGROUND

Albumin has been regarded as a potent antioxidant with free radical scavenging activities. Oxidative stress and neuronal apoptosis are responsible for its highly damaging effects on brain injury after intracerebral hemorrhage (ICH). Here, the present study investigated the neuroprotective effect of albumin against early brain injury after ICH and the potential underlying mechanisms.

METHODS

Adult male Sprague-Dawley rats were subjected to intrastriatal injection of autologous blood to induce ICH. Human serum albumin was given by intravenous injection 1 h after ICH. U0126, an inhibitor of extracellular signal-regulated kinase (ERK1/2), and ML385, an inhibitor of nuclear factor-E2-related factor 2 (Nrf2), were intraperitoneally administered 1 h before ICH induction. Short- and long-term neurobehavioral tests, western blotting, immunofluorescence staining, oxidative stress evaluations, and apoptosis measurements were performed.

RESULTS

Endogenous expression of albumin (peaked at 5 days) and heme oxygenase 1 (HO-1, peaked at 24 h) was increased after ICH compared with the sham group. Albumin and HO-1 were colocalized with neurons. Compared with vehicle, albumin treatment significantly improved short- and long-term neurobehavioral deficits and reduced oxidative stress and neuronal death at 72 h after ICH. Moreover, albumin treatment significantly promoted the phosphorylation of ERK1/2; increased the expression of Nrf2, HO-1, and Bcl-2; and downregulated the expression of Romo1 and Bax. U0126 and ML385 abolished the treatment effects of albumin on behavior and protein levels after ICH.

CONCLUSIONS

Albumin attenuated oxidative stress-related neuronal death may in part via the ERK/Nrf2/HO-1 signaling pathway after ICH in rats. Our study suggests that albumin may be a novel therapeutic method to ameliorate brain injury after ICH.

A Comprehensive Spectroscopic Analysis of the Ibuprofen Binding with Human Serum Albumin, Part I

Human serum albumin (HSA) plays a fundamental role in the human body. It takes part in the transport of exogenic and endogenic substances, especially drugs. Ibuprofen (IBU) is one of the most commonly used non-steroidal anti-inflammatory drugs, used for pain relief, fever relief, and for anti-inflammatory purposes. The binding of ligands with HSA is a significant factor which determines the toxicity and the therapeutic dosages of these substances. The aim of this study was to compare the degree of ibuprofen binding with human serum albumin at various temperatures and protein solution pH values. In order to evaluate conformational changes in HSA caused by interaction with ibuprofen, spectrophotometric (first and second derivatives of the UV-VIS spectrum), and spectrofluorometric analyses were performed concerning the mutual interactions of IBU-HSA. The use of fluorescent spectroscopy allowed for recording fluorescent emissive spectra of HSA (5 × 10^-6 mol/dm³) without and with the presence of ibuprofen (1 × 10^-5-1 × 10^-4 mol/dm³) at temperatures of 308, 310, 312, and 314 K at pH values of 6.5, 6.8, 7.4, 7.8, and 8.1. System fluorescence was excited by radiation of wavelengths of λex = 275 nm and λex = 295 nm. Based on this, original and modified Stern-Volmer, Scatchard, Klotz and Hill curves were determined. The data that were obtained showed a significant effect of temperature and pH of the human serum albumin solution on the strength and type of interaction of ibuprofen with HSA.

Impacts of admission serum albumin levels on short-term and long-term mortality in hospitalized patients

AIM

The aim of this study is to assess the association between admission serum albumin and short- and long-term mortality in all hospitalized patients.

DESIGN

A single-center cohort study.

METHODS

A retrospective cohort of all adult hospitalized patients at a tertiary referral hospital between January 2009 and December 2013 were analysed. Admission serum albumin was stratified into six groups: ≤2.4, 2.5-2.9, 3.0-3.4, 3.5-3.9, 4.0-4.4 and ≥4.5 g/dl. The outcomes of interest were in-hospital mortality, length of hospital stay and 1-year mortality. Serum albumin of 4-4.4 g/dl was selected as a reference group for outcome comparison.

RESULTS

A total of 14 075 patients were studied. Admission serum albumin of ≥4.5 g/dl had the lowest in-hospital and 1-year mortality with progressively increased in-hospital mortality observed with decreased admission serum albumin. In adjusted analysis, compared with serum albumin of 4.0-4.4 g/dl, serum albumin of ≤2.4, 2.5-2.9, 3.0-3.4 and 3.5-3.9 were significantly associated with increased in-hospital and 1-year mortality. In contrast, serum albumin of ≥4.5 g/dl was significantly associated with lower 1-year mortality but not in-hospital mortality. Admission serum albumin <4.0 g/dl was significantly associated with a prolonged hospital stay, while admission serum albumin of ≥4.5 g/dl was significantly associated with shorter hospital stay, compared with serum albumin of 4.0-4.4 g/dl.

CONCLUSION

Low albumin level at admission was progressively associated with increased short- and long-term mortality in all hospitalized patients even when albumin level was considered in normal range.

Development and validation of a simple-to-use nomogram for predicting refractory Mycoplasma pneumoniae pneumonia in children

OBJECTIVE

This study aimed to develop and validate a simple-to-use nomogram for predicting refractory Mycoplasma pneumoniae pneumonia (RMPP) in children.

METHODS

A total of 73 children with RMPP and 146 children with general Mycoplasma pneumoniae pneumonia were included. Clinical, laboratory, and radiological data were obtained. A least absolute shrinkage and selection operator (LASSO) regression model was used to determine optimal predictors. The nomogram was plotted by multivariable logistic regression. The performance of the nomogram was assessed by calibration, discrimination, and clinical utility.

RESULTS

The LASSO regression analysis identified lactate dehydrogenase, albumin, neutrophil ratio, and high fever as significant predictors of RMPP. This nomogram-illustrated model showed good discrimination, calibration, and clinical value. The area under the receiver operating characteristic curve of the nomogram was 0.884 (95% CI, 0.823-0.945) in the training set and 0.881 (95% CI, 0.807-0.955) in the validating set. Calibration curve and Hosmer-Lemeshow test showed good consistency between the predictions of the nomogram and the actual observations, and decision curve analysis showed that the nomogram was clinically useful.

CONCLUSION

A simple-to-use nomogram for predicting RMPP in early stage was developed and validated. This may help physicians recognize RMPP earlier.

Albumin-driven disassembly of lipidic nanoparticles: the specific case of the squalene-adenosine nanodrug

In the field of nanomedicine, nanostructured nanoparticles (NPs) made of self-assembling prodrugs emerged in the recent years with promising properties. In particular, squalene-based drug nanoparticles have already shown their efficiency through in vivo experiments. However, a complete pattern of their stability and interactions in the blood stream is still lacking. In this work we assess the behavior of squalene-adenosine (SQAd) nanoparticles - whose neuroprotective effect has already been demonstrated in murine models - in the presence of fetal bovine serum (FBS) and of bovine serum albumin (BSA), the main protein of blood plasma. Extensive physicochemical characterizations were performed using Small Angle Neutron Scattering (SANS), cryogenic transmission electron microscopy (Cryo-TEM), circular dichroism (CD), steady-state fluorescence spectroscopy (SSFS) and isothermal titration calorimetry (ITC) as well as in silico by means of ensemble docking simulations with human serum albumin (HSA). Significant changes in the colloidal stability of the nanoparticles in the presence of serum albumin were observed. SANS, CD and SSFS analyses demonstrated an interaction between SQAd and BSA, with a partial disassembly of the nanoparticles in the presence of BSA and the formation of a complex between SQAd and BSA. The interaction free energy of SQAd nanoparticles with BSA derived from ITC experiments, is about -8 kcal mol^-1 which is further supported in silico by ensemble docking simulations. Overall, our results show that serum albumin partially disassembles SQAd nanoparticles by extracting individual SQAd monomers from them. As a consequence, the SQAd nanoparticles would act as a circulating reservoir in the blood stream. The approach developed in this study could be extended to other soft organic nanoparticles.

Pro-inflammatory mediators and neutrophils are increased in synovial fluid from heifers with acute ruminal acidosis

BACKGROUND

Acute ruminal acidosis (ARA) is a metabolic disease of cattle characterized by an aseptic synovitis. ARA is the result of an increased intake of highly fermentable carbohydrates that frequently occurs in dairy cattle subjected to high production requirements. In human joint diseases such as rheumatoid arthritis and gout, several pro-inflammatory molecules are increased in the synovial fluid, including cytokines, prostaglandin E₂ (PGE₂), metalloproteinases, and neutrophil extracellular traps (NETs). The aim of this study was to identify the presence of proinflammatory mediators and neutrophils in the synovial fluid of heifers with ARA, induced by an oligofructose overload. Five heifers were challenged with an oligofructose overload (13 g/kg BW) dissolved in water. As a control, a similar vehicle volume was used in four heifers. Synovial fluid samples were collected from the tarso-crural joint and PGE₂, IL-6, IL-1β, ATP, lactate dehydrogenase (LDH), albumin, glucose, matrix metalloproteinase-9 (MMP-9), cellular free DNA, NETs, and serpin B1 were analyzed at 0, 9, and 24 h post treatment.

RESULTS

At 9 h post oligofructose overload, an increase of IL-1β, IL-6, PGE₂, serpin B1 and LDH was detected in the joints when compared to the control group. At 24 h, the synovial fluid was yellowish, viscous, turbid, and contained abundant neutrophils. An increase of DNA-backbone-like traps, histone 3 (H₃cit), aggregated neutrophil extracellular traps (aggNETs), and serpin B1 were observed 24 h post treatment. Furthermore, albumins, LDH, ATP, MMP-9, IL-6, and IL-1β were increased after 24 h.

CONCLUSIONS

The overall results indicate that IL-1β, IL-6 and PGE₂, were the earliest proinflammatory parameters that increased in the synovial fluid of animals with ARA. Furthermore, the most sever inflammatory response in the joint was observed after 24 h and could be associated with a massive presence of neutrophils and release of aggNETs.

The procalcitonin/albumin ratio as an early diagnostic predictor in discriminating urosepsis from patients with febrile urinary tract infection

Discrimination between urosepsis and febrile urinary tract infections is important in therapeutic decision-making to indicate suitable treatments to avoid sepsis-related organ failure. Accurate diagnosis is time-consuming and susceptible to false-positive results. Moreover, patient responses to urosepsis are complex and varied. Therefore, this study aimed to develop a new, early diagnostic predictor that could discriminate between patients with urosepsis and those with febrile urinary tract infections using a combination of initial procalcitonin and albumin levels.We conducted a retrospective study involving 140 patients with febrile urinary tract infections from January 2013 to December 2017. Univariate and multivariate logistic analyses were performed to identify the independent risk factors for differentiating urosepsis from febrile urinary tract infection. A receiver operating characteristic (ROC) curve analysis was conducted to compare the predictive accuracy of the procalcitonin/albumin ratio.Patients in the urosepsis group had higher procalcitonin/albumin ratios compared to those in the febrile urinary tract infection group [2.254 (0.978, 6.299) vs 0.021 (0.004, 0.095); P < .001]. Based on multivariate logistic analysis, the procalcitonin/albumin ratio [adjusted odds ratio (OR) 1.029, 95% confidence interval (CI) 1.013-1.045, P < .001] was an independent predictor of urosepsis, which allowed for differentiation from patients with febrile urinary tract infections. The area under the ROC curve (AUC) for the procalcitonin/albumin ratio was 0.937 (95% CI, 0.894-0.980); P < .001. The sensitivity and specificity of the procalcitonin/albumin ratio cut-off values (>0.44) were 84.62% and 96.00%, respectively. Moreover, in the subset of 65 patients with urosepsis, the procalcitonin/albumin ratio in the uroseptic shock group was higher than in the group of patients without uroseptic shock [5.46 (1.43, 6.58) vs 1.24 (0.63, 4.38); P = .009].Our study demonstrates that the procalcitonin/albumin ratio is an early diagnostic predictor that can discriminate between urosepsis and febrile urinary tract infection. Additionally, in patients with urosepsis, those with higher procalcitonin/albumin ratios were more prone to uroseptic shock. Our findings suggest that the procalcitonin/albumin ratio is a rapid and relatively low-cost biomarker that can be used in clinical practice.

Therapeutic Use of Albumin

The clinical use of albumin solutions is a controversial issue, that involves albumin as a volume plasma expander, a supplement of total parenteral nutrition and a substance with pharmacological properties. The aim of this review is to show the present role of albumin in the clinical setting. We reviewed experimental and clinical data collected by the Medline System and the bibliographies of relevant articles. Experimental studies were selected on the basis of their historical value and applicability (hypothetical use, correct use) to the clinical setting. At present, it is possible to assert that: a) exogenous albumin is not an ideal colloid; b) the effects on plasma volume expansion are not entirely predictable, especially in pathologic states accompanied by leaky capillary membranes; c) albumin supplementation shows no benefit on many kinds of tissue edema; d) the supplementation of albumin has no influence on outcome. It is possible to demonstrate the role of albumin as a substance with unique properties that make it useful, but further experimental and clinical data will be necessary and represent new areas for future exploration. Given the protein's cost, the routine use of albumin does not appear to be justified, until new data indicate otherwise.

Serum Albumin as a Biomarker of Poor Prognosis in the Pediatric Patients in Intensive Care Unit

Background

Serum albumin as an indicator of the disease severity and mortality is suggested in adult patients, but its role in pediatric patients has not been established. The objectives of this study are to investigate the albumin level as a biomarker of poor prognosis and to compare it with other mortality predictive indices in children in intensive care unit (ICU).

Methods

Medical records of 431 children admitted to the ICU at Severance Hospital from January 1, 2012 to December 31, 2015 were retrospectively analyzed. Children who expired within 24 hours after ICU admission, children with hepatic or renal failure, and those who received albumin replacement before ICU admission were excluded.

Results

The children with hypoalbuminemia had higher 28-day mortality rate (24.60% vs. 9.28%, P < 0.001), Pediatric Index of Mortality (PIM) 3 score (9.23 vs. 8.36, P < 0.001), Pediatric Risk of Mortality (PRISM) III score (7.0 vs. 5.0, P < 0.001), incidence of septic shock (12% vs. 3%, P < 0.001), C-reactive protein (33.0 mg/L vs. 5.8 mg/L, P < 0.001), delta neutrophil index (2.0% vs. 0.6%, P < 0.001), lactate level (1.6 mmol/L vs. 1.2 mmol/L, P < 0.001) and lower platelet level (206,000/μl vs. 341,000/μl, P < 0.001) compared to the children with normal albumin level. PIM 3 (r = 0.219, P < 0.001) and PRISM III (r = 0.375, P < 0.001) were negatively correlated with serum albumin level, respectively.

Conclusions

Our results highlight that hypoalbuminemia can be a biomarker of poor prognosis including mortality in the children in ICU.

Repeated Oral Administration of Human Serum Albumin Protects from the Cerebral Ischemia in Rat Brain Following MCAO

Albumin is known to have neuroprotective effects. The protein has a long half-life circulation, and its effects can therefore persist for a long time to aid in the recovery of brain ischemia. In the present study, we investigated the neuroprotective effects of human serum albumin (HSA) on brain hemodynamics. Albumin is administrated using repeated oral gavage to the rodents. Sprague-Dawley rats underwent middle cerebral artery occlusion procedures and served as a stroke model. Afterwards, 25% human serum albumin (1.25 g/kg) or saline (5 ml/kg) was orally administrated for 2 weeks in alternating days. After 2 weeks, the rodents were assessed for levels of brain ischemia. Our testing battery consists of behavioral tests and in vivo optical imaging sessions. Modified neurological severity scores (mNSS) were obtained to assess the levels of ischemia and the effects of HSA oral administration. We found that the experimental group demonstrated larger hemodynamic responses following sensory stimulation than controls that were administered with saline. HSA administration resulted in more significant changes in cerebral blood volume following direct cortical electric stimulation. In addition, the mNSS of the treatment group was lower than the control group. In particular, brain tissue staining revealed that the infarct size was also much smaller with HSA administration. This study provides support for the efficacy of HSA, and that long-term oral administration of HSA may induce neuroprotective effects against brain ischemia.

Hypoalbuminemia, Low Base Excess Values, and Tachypnea Predict 28-Day Mortality in Severe Sepsis and Septic Shock Patients in the Emergency Department

PURPOSE

The objective of this study was to develop a new nomogram that can predict 28-day mortality in severe sepsis and/or septic shock patients using a combination of several biomarkers that are inexpensive and readily available in most emergency departments, with and without scoring systems.

MATERIALS AND METHODS

We enrolled 561 patients who were admitted to an emergency department (ED) and received early goal-directed therapy for severe sepsis or septic shock. We collected demographic data, initial vital signs, and laboratory data sampled at the time of ED admission. Patients were randomly assigned to a training set or validation set. For the training set, we generated models using independent variables associated with 28-day mortality by multivariate analysis, and developed a new nomogram for the prediction of 28-day mortality. Thereafter, the diagnostic accuracy of the nomogram was tested using the validation set.

RESULTS

The prediction model that included albumin, base excess, and respiratory rate demonstrated the largest area under the receiver operating characteristic curve (AUC) value of 0.8173 [95% confidence interval (CI), 0.7605-0.8741]. The logistic analysis revealed that a conventional scoring system was not associated with 28-day mortality. In the validation set, the discrimination of a newly developed nomogram was also good, with an AUC value of 0.7537 (95% CI, 0.6563-0.8512).

CONCLUSION

Our new nomogram is valuable in predicting the 28-day mortality of patients with severe sepsis and/or septic shock in the emergency department. Moreover, our readily available nomogram is superior to conventional scoring systems in predicting mortality.

Expanding the concept of neuroprotection for acute ischemic stroke: The pivotal roles of reperfusion and the collateral circulation

This review surveys the efforts taken to achieve clinically efficacious protection of the ischemic brain and underscores the necessity of expanding our purview to include the essential role of cerebral perfusion and the collateral circulation. We consider the development of quantitative strategies to measure cerebral perfusion at the regional and local levels and the application of these methods to elucidate flow-related thresholds of ischemic viability and to characterize the ischemic penumbra. We stress that the modern concept of neuroprotection must consider perfusion, the necessary substrate upon which ischemic brain survival depends. We survey the major mechanistic approaches to neuroprotection and review clinical neuroprotection trials, focusing on those phase 3 multicenter clinical trials for acute ischemic stroke that have been completed or terminated. We review the evolution of thrombolytic therapies; consider the lessons learned from the initial, negative multicenter trials of endovascular therapy; and emphasize the highly successful positive trials that have finally established a clinical role for endovascular clot removal. As these studies point to the brain's collateral circulation as key to successful reperfusion, we next review the anatomy and pathophysiology of collateral perfusion as it relates to ischemic infarction, as well as the molecular and genetic influences on collateral development. We discuss the current MR and CT-based diagnostic methods for assessing the collateral circulation and the prognostic significance of collaterals in ischemic stroke, and we consider past and possible future therapeutic directions.

Cryopreservation of MHC multimers: Recommendations for quality assurance in detection of antigen specific T cells

Fluorescence-labeled peptide-MHC class I multimers serve as ideal tools for the detection of antigen-specific T cells by flow cytometry, enabling functional and phenotypical characterization of specific T cells at the single cell level. While this technique offers a number of unique advantages, MHC multimer reagents can be difficult to handle in terms of stability and quality assurance. The stability of a given fluorescence-labeled MHC multimer complex depends on both the stability of the peptide-MHC complex itself and the stability of the fluorochrome. Consequently, stability is difficult to predict and long-term storage is generally not recommended. We investigated here the possibility of cryopreserving MHC multimers, both in-house produced and commercially available, using a wide range of peptide-MHC class I multimers comprising virus and cancer-associated epitopes of different affinities presented by various HLA-class I molecules. Cryopreservation of MHC multimers was feasible for at least 6 months, when they were dissolved in buffer containing 5-16% glycerol (v/v) and 0.5% serum albumin (w/v). The addition of cryoprotectants was tolerated across three different T-cell staining protocols for all fluorescence labels tested (PE, APC, PE-Cy7 and Quantum dots). We propose cryopreservation as an easily implementable method for stable storage of MHC multimers and recommend the use of cryopreservation in long-term immunomonitoring projects, thereby eliminating the variability introduced by different batches and inconsistent stability.

Restricted access carbon nanotubes for direct extraction of cadmium from human serum samples followed by atomic absorption spectrometry analysis

In this paper, we propose a new sorbent that is able to extract metal ions directly from untreated biological fluids, simultaneously excluding all proteins from these samples. The sorbent was obtained through the modification of carbon nanotubes (CNTs) with an external bovine serum albumin (BSA) layer, resulting in restricted access carbon nanotubes (RACNTs). The BSA layer was fixed through the interconnection between the amine groups of the BSA using glutaraldehyde as cross-linker. When a protein sample is percolated through a cartridge containing RACNTs and the sample pH is higher than the isoelectric point of the proteins, both proteins from the sample and the BSA layer are negatively ionized. Thus, an electrostatic repulsion prevents the interaction between the proteins from the sample on the RACNTs surface. At the same time, metal ions are adsorbed in the CNTs (core) after their passage through the chains of proteins. The Cd(2+) ion was selected for a proof-of-principle case to test the suitability of the RACNTs due to its toxicological relevance. RACNTs were able to extract Cd(2+) and exclude almost 100% of the proteins from the human serum samples in an online solid-phase extraction system coupled with thermospray flame furnace atomic absorption spectrometry. The limits of detection and quantification were 0.24 and 0.80 μg L(-1), respectively. The sampling frequency was 8.6h(-1), and the intra- and inter-day precisions at the 0.80, 15.0, and 30.0 μg L(-1) Cd(2+) levels were all lower than 10.1% (RSD). The recoveries obtained for human blood serum samples fortified with Cd(2+) ranged from 85.0% to 112.0%. The method was successfully applied to analyze Cd(2+) directly from six human blood serum samples without any pretreatment, and the observed concentrations ranged from <LOQ to 2.52 µg L(-1).

Serum albumin in 2D: a Langmuir monolayer approach

Understanding of protein interaction at the molecular level raises certain difficulties which is the reason a model membrane system such as the Langmuir monolayer technique was developed. Ubiquitous proteins such as serum albumin comprise 50% of human blood plasma protein content and are involved in many biological functions. The important nature of this class of protein demands that it be studied in detail while modifying the experimental conditions in two dimensions to observe it in all types of environments. While different from bulk colloidal solution work, the two dimensional approach allows for the observation of the interaction between molecules and subphase at the air-water interface. Compiled in this review are studies which highlight the characterization of this protein using various surroundings and also observing the types of interactions it would have when at the biomembrane interface. Free-energy changes between molecules, packing status of the bulk analyte at the interface as well as phase transitions as the monolayer forms a more organized or aggregated state are just some of the characteristics which are observed through the Langmuir technique. This unique methodology demonstrates the chemical behavior and physical behavior of this protein at the phase boundary throughout the compression of the monolayer.

Effects of peritoneal dialysis on protein metabolism

Protein-energy wasting is relatively common in renal patients treated with haemodialysis or peritoneal dialysis (PD) and is associated with worse outcome. In this article, we review the current state of our knowledge regarding the effects of PD on protein metabolism and the possible interactions between PD-induced changes in protein turnover and the uraemia-induced alterations in protein metabolism. Available evidence shows that PD induces a new state in muscle protein dynamics, which is characterized by decreased turnover rates and a reduced efficiency of protein turnover, a condition which may be harmful in stress conditions, when nutrient intake is diminished or during superimposed catabolic illnesses. There is a need to develop more effective treatments to enhance the nutritional status of PD patients. New approaches include the use of amino acid/keto acids-containing supplements combined with physical exercise, incremental doses of intraperitoneal amino acids, vitamin D and myostatin antagonism for malnourished patients refractory to standard nutritional therapy.

Intravenous albumin shortens the duration of hospitalization for patients with hypoalbuminemia and bleeding peptic ulcers: a pilot study

BACKGROUND

Patients with hypoalbuminemia have an increased risk of ulcer rebleeding and longer length of hospitalization.

AIMS

This study aimed to test whether intravenous albumin can decrease the incidence of rebleeding or shorten the duration of hospitalization in patients with bleeding peptic ulcers and hypoalbuminemia.

METHODS

Sixty-two patients with bleeding peptic ulcers and Rockall scores ≥ 6 were prospectively enrolled after having received endoscopic therapy. The enrolled patients were divided into a normal albumin group (serum albumin ≥ 3 g/dL, n = 39) or an intervention group (<3 g/dL, n = 23) to receive a 3-day course of omeprazole infusion and 25-day oral esomeprazole. Patients (n = 29) with bleeding ulcers and hypoalbuminemia who received the same dose of intravenous and oral omeprazole but did not receive albumin therapy were enrolled from a previous study as the control group. In the intervention group, patients received albumin infusion (10 g q8h) for 1 day (serum albumin levels 2.5-2.9 g/dL) and 2 days (<2.5 g/dL), respectively.

RESULTS

The 28-day cumulative rebleeding rates were similar between the intervention group and the control group (39.1 vs. 42.3 %, p = 0.99). The intervention group had a shorter duration of hospitalization (9 vs. 15 days, p = 0.02) than cohort controls. The risk of rebleeding developed after discharge were similar (normal albumin group vs. intervention group vs. control group, 1/5 [20 %] vs. 2/9 [22.2 %] vs. 1/11 [9.1 %], p = 0.7).

CONCLUSIONS

Albumin administration shortens the duration of hospitalization for patients with peptic ulcer bleeding and hypoalbuminemia, but does not decrease the incidence of rebleeding.

The pre-treatment effect on brain injury during restoration of normal perfusion pressure with hemodilution in a new rat model of chronic cerebral hypoperfusion

OBJECTIVES

To investigate the effect of hemodilution with high-concentration human serum albumin (HSA) on brain injury in a rat model of chronic cerebral hypoperfusion associated with arteriovenous malformations.

METHODS

The animal model was established by creating a fistula through an end-to-side anastomosis between the right distal external jugular vein and the ipsilateral common carotid artery, followed by ligation of the left vein draining the transverse sinus and bilateral external carotid arteries. The agent (20% HSA) or control solution (0.9% sodium chloride) was administered intravenously at a dosage of 1% body weight 24 hours before ligation of the fistula. Blood-brain barrier (BBB) disruption was judged by extravasation of Evans blue (EB) dye. EB, water content and the changes of myeloperoxidase (MPO) activity and superoxide dismutase (SOD) activity in rat brains 24 hours after ligation of the fistula were determined.

RESULTS

EB and water content in rat brains of the pre-treated group were significantly decreased compared with the control group accompanied by reduction of MPO activity and enhancement of SOD activity.

DISCUSSION

Hemodilution with high-concentration HSA has a certain pre-treatment effect on brain injury after ligation of the fistula in rat model of chronic cerebral hypoperfusion, which may be resulted from improved microcirculation, decrease in inflammatory cell infiltration and inactivation of oxygen free radicals.

Phase I Comparability of Recombinant Human Albumin and Human Serum Albumin

Recombinant human albumin (rHA) is a highly purified animal-, virus-, and prion-free product developed as an alternative to human serum albumin (HSA), to which it is structurally equivalent. The present investigation compared the safety, tolerability, and pharmacokinetics/pharmacodynamics of rHA with HSA. Two double-blind, randomized trials were performed in healthy volunteers using intramuscular (IM) and intravenous (IV) administration. The IM trial included 500 volunteers, each receiving 5 repeat doses of 5 mg (100 subjects), 15 mg (100 subjects), or 65 mg (300 subjects) of rHA or HSA. Thirty volunteers participated in the IV trial, each receiving ascending doses (10 g, 20 g, and 50 g) of either rHA or HSA. In both trials, all adverse events were recorded and conventionally classified; potential allergic responses were also monitored. Blood samples were taken in both studies to test for IgG or IgE antibodies against test products and potential impurities. For the IV study, pharmacokinetic/pharmacodynamic assessments were performed, including measurement of serum albumin, colloid osmotic pressure, and hematocrit pre- and postinfusion. Nine subjects in the IM study (4 recipients of rHA and 5 of HSA) reported drug-related, potentially allergic events; all but 2 of these were skin related. No serious or potentially allergic events were reported with either product in the IV study. There was no immunological response to either product, and dose level did not influence the study outcomes. Serum albumin, colloid osmotic pressure changes, and hematocrit ratio were as expected, with no differences between rHA and HSA. rHA and HSA exhibited similar safety, tolerability, and pharmacokinetic/pharmacodynamic profiles, with no evidence of any immunological response.

Role of lipase-generated free fatty acids in converting mesenteric lymph from a noncytotoxic to a cytotoxic fluid

Recent studies have shown that mesenteric lymph plays a very important role in the development of multiple-organ dysfunction syndrome under critical conditions. Great efforts have been made to identify the biologically active molecules in the lymph. We used a trauma-hemorrhagic shock (T/HS) model and the superior mesenteric artery occlusion (SMAO) model, representing a global and a localized intestinal ischemia-reperfusion insult, respectively, to investigate the role of free fatty acids (FFAs) in the cytotoxicity of mesenteric lymph in rats. Lymph was collected before, during, and after (post) shock or SMAO. The post-T/HS and SMAO lymph, but not the sham lymph, manifested cytotoxicity for human umbilical vein endothelial cells (HUVECs). HUVEC cytotoxicity was associated with increased FFAs, especially the FFA-to-protein ratio. Addition of albumin, especially delipidated albumin, reduced this cytotoxicity. Lipase treatment of trauma-sham shock (T/SS) lymph converted it from a noncytotoxic to a cytotoxic fluid, and its toxicity correlated with the FFA-to-protein ratio in a fashion similar to that of the T/HS lymph, further suggesting that FFAs were the key components leading to HUVEC cytotoxicity. Analysis of lymph by gas chromatography revealed that the main FFAs in the post-T/HS or lipase-treated T/SS lymph were palmitic, stearic, oleic, and linoleic acids. When added to the cell culture at levels comparable to those in T/HS lymph, all these FFAs were cytotoxic, with linoleic acid being the most potent. In conclusion, this study suggests that lipase-generated FFAs are the key components resulting in the cytotoxicity of T/HS and SMAO mesenteric lymph.

Docosahexaenoic acid complexed to human albumin in experimental stroke: neuroprotective efficacy with a wide therapeutic window

BACKGROUND

Docosahexaenoic acid (DHA) complexed to human serum albumin (Alb) is neuroprotective after experimental stroke. Here we tested using lower concentrations of albumin as part of the complex to achieve neuroprotection. We found that lower Alb concentrations extend the therapeutic window of protection beyond 5 h after stroke onset.

METHODS

Sprague-Dawley rats were received 2 h middle cerebral artery occlusion (MCAo). The behavior was evaluated on day 1, 2, 3 and 7 after MCAo. In the dose-response study, animals were given either DHA (5mg/kg), Alb (0.63g/kg), DHA-Alb (5mg/kg + 0.32, 0.63 or 1.25 g/kg) or saline, i.v. 3 h after onset of stroke (n=6-8 per group). In the therapeutic window study, DHA-Alb (5mg/kg + 1.25g/kg) was administered i.v. at either 3, 4, 5, 6 or 7 h after onset of stroke (n=7-9 per group). Alb (1.25g/kg) was given at 3 h or 5 h and saline at 3h after onset of reperfusion. Seven days after MCAo, infarct volumes and number of GFAP, ED-1, NeuN, SMI-71 positive cells and vessels were counted.

RESULTS

Moderate DHA-Alb doses (0.63 and 1.25 g/kg) improved neurological scores compared to albumin-treated rats on days 1, 2, 3 and 7. All DHA-Alb doses (0.32, 0.63 and 1.25 g/kg) markedly reduced cortical (by 65-70%), striatal (by 52-63%) and total infarct volumes (by 60-64%) compared to native Alb group. In the therapeutic window study DHA-Alb led to improved neurological score and significant reductions of infarct volumes (especially in the cortical or penumbral region), even when treatment was initiated as late as 7 hours after onset of MCAo.

CONCLUSIONS

The DHA-Alb complex affords high-grade neurobehavioral neuroprotection in focal cerebral ischemia, equaling or exceeding that afforded by native Alb or DHA, at considerably moderate doses. It has a broad therapeutic window extending to 7 h after stroke onset. Taken together, these finding support the potential clinical feasibility of administering DHA-Alb therapy to patients with acute ischemic stroke.

Serum albumin in relation to change in muscle mass, muscle strength, and muscle power in older men

OBJECTIVES

To investigate the relationship between serum albumin and change in muscle mass, grip strength, and leg power.

DESIGN

Prospective cohort.

SETTING

Six U.S. academic medical centers.

PARTICIPANTS

Community-dwelling men aged 65 and older participating in the Osteoporotic Fractures in Men (MrOS) Study.

MEASUREMENTS

Serum albumin was measured at baseline in 5,534 participants. Baseline serum albumin was examined in relation to change in appendicular skeletal muscle (ASM) mass, grip strength, and leg power after 2 and 4.6 years. Two-year change in serum albumin was examined with respect to simultaneous change in these outcomes in 1,267 participants.

RESULTS

Baseline serum albumin <40 g/L was not associated with 2- or 4.6-year change in ASM mass, grip strength, or leg power before or after adjustment for confounders. There was no association between serum albumin change and change in grip strength. A statistically significant trend was observed between serum albumin change and change in ASM mass, but there was substantial overlap across confidence intervals (CIs). Participants with a marked decrease (>3 g/L) and mild decrease (1-2 g/L) in serum albumin over 2 years exhibited a modest change of -8.9 W (95% CI = -25.6 to -7.8 W) and -6.3 W (95% CI = -21.2 to -8.5 W) of leg power, respectively (P for trend = .02), compared with those with no decrease in albumin concentration.

CONCLUSION

Serum albumin demonstrated modest and inconsistent trends with loss of muscle mass and function. Low serum albumin within the normal range is not a risk factor for this process in elderly men.

Human albumin prevents 6-hydroxydopamine-induced loss of tyrosine hydroxylase in in vitro and in vivo

Human albumin has recently been demonstrated to protect brain neurons from injury in rat ischemic brain. However, there is no information available about whether human albumin can prevent loss of tyrosine hydroxylase (TH) expression of dopaminergic (DA) neurons induced by 6-hydroxydopamine (6-OHDA) toxicity that is most commonly used to create a rat model of Parkinson's disease (PD). In the present study, two microliters of 1.25% human albumin were stereotaxically injected into the right striatum of rats one day before or 7 days after the 6-OHDA lesion in the same side. D-Amphetamine-induced rotational asymmetry was measured 7 days, 3 and 10 weeks after 6-OHDA lesion. We observed that intrastriatal administration of human albumin significantly reduced the degree of rotational asymmetry. The number of TH-immunoreactive neurons present in the substantia nigra was greater in 6-OHDA lesioned rats following human albumin-treatment than non-human albumin treatment. TH-immunoreactivity in the 6-OHDA-lesioned striatum was also significantly increased in the human albumin-treated rats. To examine the mechanisms underlying the effects of human albumin, we challenged PC12 cells with 6-OHDA as an in vitro model of PD. Incubation with human albumin prevented 6-OHDA-induced reduction of cell viability in PC12 cell cultures, as measured by MTT assay. Furthermore, human albumin reduced 6-OHDA-induced formation of reactive oxygen species (ROS) and apoptosis in cultured PC12 cells, as assessed by flow cytometry. Western blot analysis showed that human albumin inhibited 6-OHDA-induced activation of JNK, c-Jun, ERK, and p38 mitogen-activated protein kinases (MAPK) signaling in PC12 cultures challenged with 6-OHDA. Human albumin may protect against 6-OHDA toxicity by influencing MAPK pathway followed by anti-ROS formation and anti-apoptosis.

The effect of PAMAM dendrimers on human and bovine serum albumin at different pH and NaCl concentrations

The effect of PAMAM G3.5, PAMAM G4 and PAMAM-OH G4 dendrimers on human and bovine serum albumins has been studied by fluorescence spectroscopy at different pH and ionic strength. It has been shown that the interactions between dendrimers and proteins depend on pH and the efficiency of interactions can be regulated by changing pH. The maximal pH dependence was observed for interactions between albumins and PAMAM G4 dendrimer. At physiological pH all dendrimers affect proteins in the maximum degree. Dendrimers had no effect on N-F and N-B transitions of albumins. The effect of dendrimers on HSA was smaller than for BSA. The increase of NaCl concentration led to a decrease of interactions between dendrimers and proteins.

In vitrophotosensitizing efficacy of cationic phthalocyanine derivatives againstC.albicans: effect of serum albumins

The effect of serum albumins (as Fetal Calf Serum) on in vitro photosensing efficacy against C.albicans of three cationic Zn ( II ) phthalocyanine derivatives was evaluated. A clearly structure-dependent reduction in the antifungine activity was observed. For this reason the binding of the photosensitizers with albumins (as bovine serum albumin, BSA) at pH 7.4 was studied. Because of aggregation phenomena, the phthalocyanine derivatives showed little fluorescence in aqueous solutions and fluorescence intensity increased as a function of protein concentration. Titration plots were built and binding constant were determined. The obtained binding parameters and the hydrolipophilic properties of the studied molecules (octanol/water partition coefficient PO / W, number of cationic charges, amphipilicity) were correlated with the observed biological effect.

Fluid balance and colloid osmotic pressure in acute respiratory failure: optimizing therapy

Acute lung injury and acute respiratory distress syndrome continue to be major causes of morbidity and mortality in the intensive care unit due to a lack of specific effective therapy. Affecting nearly 200,000 people every year in the USA alone, patients with this syndrome often require extensive intensive care unit and hospital care, leading to enormous utilization of healthcare resources and significant expenditures, and ultimately leaving survivors with a reduced quality of life. A disease of altered capillary permeability, acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is characterized by significant fluid imbalances and oncotic pressure changes. Although investigations directed at these abnormalities may improve patient-centered outcomes, fluid management in ALI/ARDS continues to be a source of great controversy. In this review, we discuss fluid balance and the colloid osmotic pressure gradients in ALI/ARDS, followed by a review of the prognostic implications of increasing extravascular lung water, and conclude with contemporary approaches to optimizing therapy in this condition, including the role of albumin and diuretic therapy.

α-Linolenic acid prevents endoplasmic reticulum stress-mediated apoptosis of stearic acid lipotoxicity on primary rat hepatocytes

Aims

Lipid accumulation in non-adipose tissues leads to cell dysfunction and apoptosis, a phenomenon known as lipotoxicity. Unsaturated fatty acids may offset the lipotoxicity associated with saturated fatty acids. Stearic acid induced endoplasmic reticulum (ER) stress and caused apoptotic and necrotic cell death in the primary rat hepatocytes.

Methods

Cell viability was investigated using MTT assay, and apoptosis was evaluated with Hoechst 33342 staining. Western blot analysis was used to examine the changes in the expression levels of glucose regulated protein 78 (GRP78), glucose regulated protein 94 (GRP94), and C/EBP homologous protein (CHOP). Caspase-3 activity was evaluated using a Caspase-3 substrate kit.

Results

We have studied the ability of α-linolenic acid to prevent endoplasmic reticulum stress-mediated apoptosis of rat hepatocytes elicited by stearic acid and thapsigargin. Incubation of primary rat hepatocytes for 16 h with stearic acid produced a significant increase in cell death. Stearic acid also increased levels of three indicators of ER stress -- GRP78, CHOP, and GRP94. α-Linolenic acid distinctly reduced cell death and levels of all three indicators of ER stress brought about by stearic acid. Thapsigargin, which induces ER stress produced similar effects to those obtained using stearic acid; its effects were partly reversed by α-linolenic acid.

Conclusion

These results suggest that α-linolenic acid prevents ER stress-mediated apoptosis of stearic acid lipotoxicity on primary rat hepatocytes might become a target to develop new antiapoptotic compounds in nonalcoholic fatty liver disease (NAFLD).

Current perspectives on potential role of albumin in neuroprotection

Albumin is the most abundant plasma protein synthesised mainly in the liver. It is also a major component of extracellular fluids including cerebrospinal fluid, interstitial fluid and lymph. Albumin has several biochemical properties including regulation of colloid osmotic pressure of plasma, transportation of hormones, fatty acids, drugs and metabolites across plasma, regulation of microvascular permeability, antioxidant activity, anti-thrombotic activity and anti-inflammatory activity. This multifunctional protein has been implicated in many neurological diseases owing to its ability to regulate hemodynamic properties of the brain circulation as well as the direct neuroprotective actions on neuronal and glial cells. In this review, we summarise various neuroprotective actions of the albumin in the brain. In experimental ischemic stroke, exogenous human serum albumin administration has been found to be neuroprotective via reducing brain swelling, prevention of post-ischemic thrombosis, anti-oxidant activity, hemodilution and increasing the perfusion to the ischemic tissue. Also, human serum albumin administration is currently under clinical trials for treatment of cerebral ischemia. In the experimental models of Alzheimer's disease, albumin has been implicated in neuroprotection by inhibiting polymerisation and enhancing the clearance of amyloid β. The direct neuroprotective actions on neuronal and glial cells are mediated via endogenously produced albumin or cellular uptake of blood derived albumin. These neuroprotective effects of albumin are partly attributed to anti-oxidant property and modulation of intracellular signalling of neuronal or glial cells. The recent finding of de novo synthesis of albumin in microglial cells directs us to explore newer roles of this endogenously produced multifunctional protein in normal as well as pathological conditions of the brain.

Protein-energy wasting and mortality in chronic kidney disease

Protein-energy wasting (PEW) is common in patients with chronic kidney disease (CKD) and is associated with an increased death risk from cardiovascular diseases. However, while even minor renal dysfunction is an independent predictor of adverse cardiovascular prognosis, PEW becomes clinically manifest at an advanced stage, early before or during the dialytic stage. Mechanisms causing loss of muscle protein and fat are complex and not always associated with anorexia, but are linked to several abnormalities that stimulate protein degradation and/or decrease protein synthesis. In addition, data from experimental CKD indicate that uremia specifically blunts the regenerative potential in skeletal muscle, by acting on muscle stem cells. In this discussion recent findings regarding the mechanisms responsible for malnutrition and the increase in cardiovascular risk in CKD patients are discussed. During the course of CKD, the loss of kidney excretory and metabolic functions proceed together with the activation of pathways of endothelial damage, inflammation, acidosis, alterations in insulin signaling and anorexia which are likely to orchestrate net protein catabolism and the PEW syndrome.