Albumin gene expression is down-regulated by albumin or macromolecule infusion in the rat

Mechanistic insight into association of lysozyme, serum albumin, and insulin with aloin: Thermodynamic and conformational analysis

Lysozyme, serum albumin, and insulin carry out essential functions in the living systems. The properties and functions of these proteins may be positively impacted in association with Aloe vera, which is known to have usefulness as dietary supplement and clinical conditions. In this work, the conformational changes in these proteins have been analysed as a result of interaction with aloin, which has a long history of use in traditional health management. A combination of circular dichroism spectroscopy, fluorescence spectroscopy, and isothermal titration calorimetry have been used in analysing the associated thermodynamic signatures and structural changes. It is observed that lysozyme, and bovine serum albumin showed weak binding behaviour with aloin at molar ratio of (1:1), which is found to be entropically driven at first binding site while enthalpically driven at second binding site. Similarly for insulin also, the interaction of aloin increased with increase in its concentration and the binding of ligand at first and second site is entropically and enthalpically driven, respectively. These three proteins offer hydrophobic and hydrophilic functionalities for establishing intermolecular interactions with aloin. Differential scanning calorimetry and circular dichroism spectroscopy have provided mechanistic details on tertiary structural changes in these proteins as a result of interactions. The results offer valuable insights into molecular mechanism of conformational changes in these proteins and hence their properties in association with aloin, thereby, having biological implications related to health and food industry.

In-vitro evidence indicating that IL-10 causes aging-related hypoalbuminemia via JAK1/STAT3 and CEBP-β

Albumin (ALB) has numerous vital physiological outcomes for healthy aging. A decrease in serum albumin, i.e., hypoalbuminemia, is one of the risk factors associated with aging, which affects physiological functioning. Hypoalbuminemia is the outcome of either decreased ALB synthesis or increased degradation. However, the potential mechanism controlling ALB's mRNA level expression in aged individuals is yet to be explored. We noted decreased serum ALB concentrations in aged individuals participating in our study, as compared to the young ones. We found that IL-10, a paradoxical inflammaging marker, reduced ALB concentration in HepG2 cells. Inhibiting the JAK/STAT3 signalling increased albumin mRNA suggesting its IL-10-driven regulation via JAK/STAT3 pathway. Albumin promotor analysis revealed the presence of a CEBP-β binding site. We showed that CEBP-β binds to the albumin promoter in an IL-10-dependent manner. Further, IL-10 increased the expressions of all CEBP-β isoforms, including the inhibitory isoform (LIP). The CEBP-β inhibition either by a functional inhibitor (i.e., quercetin) or shRNA silencing increased albumin mRNA in HepG2 cells. Our finding showed that IL-10 likely regulates albumin expression in a JAK/STAT3 and CEBP-β dependent manner in aging. A better understanding of the underlying condition can improve albumin protein levels and the well-being of the aged population.

Effects of amino acids and albumin administration on albumin metabolism in surgically stressed rats: A basic nutritional study

BACKGROUND

Nutrition therapy and administration of albumin preparations are common in postsurgical patients. However, the effects of these interventions on albumin metabolism are unclear. We elucidated the effect of postoperative albumin and/or parenteral nutrition administration on it.

METHODS

Sprague-Dawley rats underwent surgery involving intestinal rubbing followed by intestinal exposure. Subsequently, they were administered experimental solutions for 48 h, their blood samples were collected at 24 and 48 h, and livers were excised at 48 h. Based on experimental solutions, rats were divided into five groups: non-surgical (Non-surg); glucose and electrolyte solution (GE); amino acid, glucose, and electrolyte solution (AGE); GE + rat serum albumin (Alb) (GE + Alb); and AGE + Alb. Their plasma albumin concentrations; albumin fractional synthesis rate (ALB FSR); mercaptoalbumin/total albumin ratio (MA ratio); and messenger RNA (mRNA) expressions of albumin and hepatocyte nuclear factor-1 (HNF-1) in the liver were measured.

RESULTS

The GE and AGE groups showed significant decline in albumin concentrations. ALB FSR was significantly enhanced in the AGE group compared with the GE group. The mRNA expression of albumin was similar to ALB FSR in all groups and that of HNF-1 was significantly decreased in the GE + Alb and AGE + Alb groups compared with the Non-surg group. The MA ratio in the AGE group was similar to the Non-surg group.

CONCLUSION

The administration of amino acids comprising parenteral nutrition after surgery augmented ALB FSR and maintained the MA ratio only without simultaneous albumin administration.

High level of polarized engraftment of porcine intrahepatic cholangiocyte organoids in decellularized liver scaffolds

In Europe alone, each year 5500 people require a life-saving liver transplantation, but 18% die before receiving one due to the shortage of donor organs. Whole organ engineering, utilizing decellularized liver scaffolds repopulated with autologous cells, is an attractive alternative to increase the pool of available organs for transplantation. The development of this technology is hampered by a lack of a suitable large-animal model representative of the human physiology and a reliable and continuous cell source. We have generated porcine intrahepatic cholangiocyte organoids from adult stem cells and demonstrate that these cultures remained stable over multiple passages whilst retaining the ability to differentiate into hepatocyte- and cholangiocyte-like cells. Recellularization onto porcine scaffolds was efficient and the organoids homogeneously differentiated, even showing polarization. Our porcine intrahepatic cholangiocyte system, combined with porcine liver scaffold paves the way for developing whole liver engineering in a relevant large-animal model.

Integrative Role of Albumin: Evolutionary, Biochemical and Pathophysiological Aspects

Being one of the main proteins in the human body and many animal species, albumin plays a crucial role in the transport of various ions, electrically neutral molecules and in maintaining the colloidal osmotic pressure of the blood. Albumin is able to bind almost all known drugs, many nutraceuticals and toxic substances, determining their pharmaco- and toxicokinetics. However, albumin is not only the passive but also the active participant of the pharmacokinetic and toxicokinetic processes possessing a number of enzymatic activities. Due to the thiol group of Cys34, albumin can serve as a trap for reactive oxygen and nitrogen species, thus participating in redox processes. The interaction of the protein with blood cells, blood vessels, and also with tissue cells outside the vascular bed is of great importance. The interaction of albumin with endothelial glycocalyx and vascular endothelial cells largely determines its integrative role. This review provides information of a historical nature, information on evolutionary changes, inflammatory and antioxidant properties of albumin, on its structural and functional modifications and their significance in the pathogenesis of some diseases.

Serum Albumin in Health and Disease: Esterase, Antioxidant, Transporting and Signaling Properties

Being one of the main proteins in the human body and many animal species, albumin plays a decisive role in the transport of various ions-electrically neutral and charged molecules-and in maintaining the colloidal osmotic pressure of the blood. Albumin is able to bind to almost all known drugs, as well as many nutraceuticals and toxic substances, largely determining their pharmaco- and toxicokinetics. Albumin of humans and respective representatives in cattle and rodents have their own structural features that determine species differences in functional properties. However, albumin is not only passive, but also an active participant of pharmacokinetic and toxicokinetic processes, possessing a number of enzymatic activities. Numerous experiments have shown esterase or pseudoesterase activity of albumin towards a number of endogeneous and exogeneous esters. Due to the free thiol group of Cys34, albumin can serve as a trap for reactive oxygen and nitrogen species, thus participating in redox processes. Glycated albumin makes a significant contribution to the pathogenesis of diabetes and other diseases. The interaction of albumin with blood cells, blood vessels and tissue cells outside the vascular bed is of great importance. Interactions with endothelial glycocalyx and vascular endothelial cells largely determine the integrative role of albumin. This review considers the esterase, antioxidant, transporting and signaling properties of albumin, as well as its structural and functional modifications and their significance in the pathogenesis of certain diseases.

Should Insulin-dependent Diabetic Patients Be Screened for Malnutrition Before Total Joint Arthroplasty? A Cohort at Risk

INTRODUCTION

The association of malnutrition in the morbidly obese cohort has led to recommendations for preoperative screening before total joint arthroplasty (TJA). However, despite the connection between diabetes and poor nutrition, preoperative screening in the diabetic cohort has not been closely examined. This study compared malnutrition risk between diabetic patients and morbidly obese patients undergoing TJA and investigated the association of malnutrition on 30-day postoperative TJA outcomes in the diabetic cohort.

METHODS

The National Surgical Quality Improvement Program database was queried, and primary TJA patients were identified for inclusion. Patients were stratified by body mass index and diabetes, and outcomes were reported as two composite groups: complications and infections in the 30-day postoperative period. Univariate and multivariate regressions were used for the analysis.

RESULTS

Patients with insulin-dependent diabetes mellitus (IDDM) were at a high risk of being malnourished in both the morbidly obese and nonmorbidly obese populations (frequencies of 11.9% and 9.9%, respectively). Patients with IDDM, but without morbid obesity, were 1.5x more often malnourished than morbidly obese patients without diabetes mellitus (9.9% versus 6.4%, respectively, P < 0.001). In a multivariate analysis among patients with co-occurring diabetes and malnutrition, patients with IDDM were at greatest risk for postoperative complications and infection (odds ratio 2.081 [1.652, 2.621]; P < 0.001 and odds ratio 1.894 [1.231, 2.913]; P = 0.004, respectively).

DISCUSSION

Patients with IDDM are at high risk for malnutrition, and increased vigilance should be maintained in this cohort before TJA to optimize outcomes. Future studies should further investigate the utility of preoperative malnutrition screening in this cohort.

HepaRG Maturation in Silk Fibroin Scaffolds: Toward Developing a 3D In Vitro Liver Model

In vitro liver models are necessary tools for the development of new therapeutics. HepaRG cells are a commonly used cell line to produce hepatic progenitor cells and hepatocytes. This study demonstrates for the first time the suitability of 3% silk scaffolds to support HepaRG growth and differentiation. The modulus and pore size of 3% silk scaffolds were shown to be within the desired range for liver cell growth. The optimal seeding density for HepaRG cells on silk scaffolds was determined. The growth and maturation of scaffolded HepaRG cells was evaluated for 28 days, where the first 14 days of culture were a proliferation period and the last 14 days of culture were a differentiation period using dimethyl sulfoxide (DMSO) treatment. After the first 14 days of culture, the scaffolded HepaRG cells exhibited increased metabolic activity and albumin secretion compared to monolayer cultured controls and preserved these attributes through the duration of culture. Additionally, after the first 14 days of culture, the scaffolded HepaRG cells displayed a significantly reduced expression of genes associated with hepatocyte maturation. This difference in expression was no longer apparent after 28 days of culture, suggesting that the cells underwent rapid differentiation within the scaffold. The functionalization of silk scaffolds with extracellular matrix (ECM) components (type I collagen and/or an arginylglycylaspartic acid (RGD)-containing peptide) was investigated to determine the impact on HepaRG cell attachment and maturation. The inclusion of ECM components had no noticeable impact on cell attachment but did significantly influence CYP3A4 expression and albumin secretion. Finally, the matrix support provided by the 3% silk scaffolds could prime the HepaRG cells for steatosis liver model applications, as evidenced by lipid droplet accumulation and expression of steatosis-related genes after 24 h of exposure to oleic acid. Overall, our work demonstrates the utility of silk scaffolds in providing a modifiable platform for liver cell growth.

Serum Albumin Redox States: More Than Oxidative Stress Biomarker

Serum albumin is the most abundant circulating protein in mammals including humans. It has three isoforms according to the redox state of the free cysteine residue at position 34, named as mercaptalbumin (reduced albumin), non-mercaptalbumin-1 and -2 (oxidized albumin), respectively. The serum albumin redox state has long been viewed as a biomarker of systemic oxidative stress, as the redox state shifts to a more oxidized state in response to the severity of the pathological condition in various diseases such as liver diseases and renal failures. However, recent ex vivo studies revealed oxidized albumin per se could aggravate the pathological conditions. Furthermore, the possibility of the serum albumin redox state as a sensitive protein nutrition biomarker has also been demonstrated in a series of animal studies. A paradigm shift is thus ongoing in the research field of the serum albumin. This article provides an updated overview of analytical techniques for serum albumin redox state and its association with human health, focusing on recent findings.

Clinical and Prognostic Values of ALBI Score in Patients With Acute Heart Failure

BACKGROUND

Although liver dysfunction is one of the common complications in patients with acute heart failure (AHF), no integrated marker has been defined. The albumin-bilirubin (ALBI) score has recently been proposed as a novel, clinically-applicable scoring system for liver dysfunction. We investigated the utility of the ALBI score in patients with AHF compared to that for a preexisting liver dysfunction score, the Model of End-Stage Liver Disease Excluding prothrombin time (MELD XI) score.

METHODS

We evaluated ALBI and MELD XI scores in 1,190 AHF patients enrolled in the prospective, multicentre Registry Focused on Very Early Presentation and Treatment in Emergency Department of Acute Heart Failure study. The associations between the two scores and the clinical profile and prognostic predictive ability for 1-year mortality were evaluated.

RESULTS

The mean MELD XI and ALBI scores were 13.4±4.8 and -2.25±0.48, respectively. A higher ALBI score, but not higher MELD XI score, was associated with findings of fluid overload. After adjusting for pre-existing prognostic factors, the ALBI score (HR 2.11, 95% CI: 1.60-2.79, p<0.001), but not the MELD XI score (HR 1.02, 95% CI: 0.99-1.06, p=0.242), was associated with 1-year mortality. Likewise, area under the receiver-operator-characteristic curves for 1-year mortality significantly increased when the ALBI score (0.71 vs. 0.74, p=0.020), but not the MELD XI score (0.71 vs. 0.72, p=0.448), was added to the pre-existing risk factors.

CONCLUSIONS

The ALBI score is potentially a suitable liver dysfunction marker that incorporates information on fluid overload and prognosis in patients with AHF. These results provide new insights into heart-liver interactions in AHF patients.

Effects of Albumin Treatment on Systemic and Portal Hemodynamics and Systemic Inflammation in Patients With Decompensated Cirrhosis

BACKGROUND & AIMS

We investigated the effect of albumin treatment (20% solution) on hypoalbuminemia, cardiocirculatory dysfunction, portal hypertension, and systemic inflammation in patients with decompensated cirrhosis with and without bacterial infections.

METHODS

We performed a prospective study to assess the effects of long-term (12 weeks) treatment with low doses (1 g/kg body weight every 2 weeks) and high doses (1.5 g/kg every week) of albumin on serum albumin, plasma renin, cardiocirculatory function, portal pressure, and plasma levels of cytokines, collecting data from 18 patients without bacterial infections (the Pilot-PRECIOSA study). We also assessed the effect of short-term (1 week) treatment with antibiotics alone vs the combination of albumin plus antibiotics (1.5 g/kg on day 1 and 1 g/kg on day 3) on plasma levels of cytokines in biobanked samples from 78 patients with bacterial infections included in a randomized controlled trial (INFECIR-2 study).

RESULTS

Circulatory dysfunction and systemic inflammation were extremely unstable in many patients included in the Pilot-PRECIOSA study; these patients had intense and reversible peaks in plasma levels of renin and interleukin 6. Long-term high-dose albumin, but not low-dose albumin, was associated with normalization of serum level of albumin, improved stability of the circulation and left ventricular function, and reduced plasma levels of cytokines (interleukin 6, granulocyte colony-stimulating factor, interleukin 1 receptor antagonist, and vascular endothelial growth factor) without significant changes in portal pressure. The immune-modulatory effects of albumin observed in the Pilot-PRECIOSA study were confirmed in the INFECIR-2 study. In this study, patients given albumin had significant reductions in plasma levels of cytokines.

CONCLUSIONS

In an analysis of data from 2 trials (Pilot-PRECIOSA study and INFECIR-2 study), we found that albumin treatment reduced systemic inflammation and cardiocirculatory dysfunction in patients with decompensated cirrhosis. These effects might be responsible for the beneficial effects of albumin therapy on outcomes of patients with decompensated cirrhosis. ClinicalTrials.gov, Numbers: NCT00968695 and NCT03451292.

Association of Pre-End-Stage Renal Disease Serum Albumin With Post-End-Stage Renal Disease Outcomes Among Patients Transitioning to Dialysis

OBJECTIVE

Serum albumin is a marker of malnutrition and inflammation and has been demonstrated as a strong predictor of mortality in chronic kidney disease (CKD) and end-stage renal disease (ESRD) patients. Yet, whether serum albumin levels in late-stage CKD are associated with adverse outcomes after the transition to ESRD is unknown. We hypothesize that lower levels and a decline in serum albumin in late-stage CKD are associated with higher risk of mortality and hospitalization rates 1 year after transition to ESRD.

DESIGN AND METHODS

This retrospective cohort study included 29,124 US veterans with advanced CKD transitioning to ESRD between 2007 and 2015. We evaluated the association of pre-ESRD (91 days before transition) serum albumin with 12-month post-ESRD all-cause, cardiovascular, and infection-related mortalities and hospitalization rates as well as the association of 1-year pre-ESRD albumin slope and 12-month post-ESRD mortality using hierarchical multivariable adjustments.

RESULTS

There was a negative linear association between serum albumin and all-cause mortality, such that risk doubled (hazard ratio [HR]: 2.07, 95% confidence interval [CI]: 1.87, 2.28) for patients with the lowest serum albumin <2.8 g/dL (ref: ≥4.0 g/dL) after full adjustment. A consistent relationship was observed between serum albumin and cardiovascular and infection-related mortality, and hospitalization outcomes. An increase in serum albumin of >0.25 g/dL/year was associated with reduced mortality risk (HR: 0.76, 95% CI: 0.63, 0.91) compared with a slight decline in albumin (ref: >-0.25 to 0 g/dL/year), whereas a decline more than 0.5 g/dL/year was associated with a 55% higher risk in mortality (HR: 1.55, 95% CI: 1.43, 1.68) in fully adjusted models.

CONCLUSIONS

Lower pre-ESRD serum albumin was associated with higher post-ESRD all-cause, cardiovascular, and infection-related mortalities and hospitalization rates. Declining serum albumin levels in the pre-ESRD period were also associated with worse 12-month post-ESRD mortality.

Propensity-Score Matched Comparative Study on Effects of Intravenous Human Serum Albumin Administration in Critically Ill Adult Patients Receiving Parenteral Nutrition

BACKGROUND

The objective of this study was to assess the effect of intravenous human serum albumin administration (IV HSA) on nutrition markers, including non-serum-albumin plasma protein levels, in adult critically ill patients receiving parenteral nutrition (PN).

METHODS

This was a retrospective study of prospectively collected data. Patients included in an initial cohort were patients who initiated IV HSA within 24 hours of start of PN. A second cohort who did not received IV HSA during PN was manually selected, matching several variables. Subsequently, both cohorts were propensity-score matched, resulting in 2 final cohorts: the cohort receiving IV HSA (ALB) and the cohort not receiving IV HSA (NOALB).

RESULTS

A total of 42 patients, 21 in each cohort, entered the study. Both cohorts were similar in demographics, anthropometrics, comorbidities, diagnoses, PN composition, and severity of the disease, biochemistry, and nutrition markers. Patients in the ALB cohort received IV HSA at a dose of 30.0 g/day during 5 days. The ALB cohort presented higher values of final serum albumin level and serum albumin level change from baseline, but also presented lower values of final non-serum-albumin plasma protein levels and their change and lower final prealbumin. In addition, bilirubin in the ALB cohort increased, whereas it decreased in the NOALB cohort.

CONCLUSION

Patients receiving IV HSA and PN for several days increased serum albumin level, but decreased non-serum-albumin plasma protein levels. In addition, bilirubin clearance could be slightly impaired in these patients.

Potential Role of Amino Acid/Protein Nutrition and Exercise in Serum Albumin Redox State

Albumin is the major protein in the serum of mammals. It is synthesized exclusively in the liver, before being secreted into the circulation. Similar to skeletal muscle protein, albumin synthesis is stimulated by dietary amino acids and proteins as well as exercise. Albumin has three isoforms based on the redox states of the free cysteine residue at position 34. The redox state of serum albumin has long been extensively investigated in terms of oxidative stress-related chronic diseases, with the redox state of serum albumin having been regarded as a marker of systemic oxidative stress. However, according to recent animal studies, the redox state of serum albumin is modulated by albumin turnover and may also reflect amino acid/protein nutritional status. Furthermore, as the redox state of serum albumin is modulated by exercise training, measuring the pre- and post-exercise redox states of serum albumin in athletes may be useful in assessing amino acid/protein nutritional status and exercise-induced oxidative stress, which are closely associated with skeletal muscle adaptive responses. This article extensively reviews serum albumin and the redox state of albumin in the context of amino acid/protein nutritional status and exercise training.

Unexpected Normal Colloid Osmotic Pressure in Clinical States with Low Serum Albumin

BACKGROUND

In clinical states associated with systemic oxidative stress (OS) and inflammation such as chronic kidney disease (CKD), oxidative modifications of serum albumin impair its quantification, resulting in apparent hypoalbuminemia. As the maintenance of oncotic pressure/colloid osmotic pressure (COP) is a major function of albumin, this study examined the impact of albumin oxidation on COP, both in-vivo and in-vitro.

METHODS

Patients with proteinuria and patients on chronic hemodialysis (HD) with systemic inflammation and OS were enrolled. Blood samples were collected from 134 subjects: 32 healthy controls (HC), proteinuric patients with high (n = 17) and low (n = 31) systemic inflammation and from 54 patients on chronic hemodialysis (HD) with the highest levels of OS and inflammation.

RESULTS

In-vitro oxidized albumin showed significantly higher COP values than non-oxidized albumin at identical albumin levels. In vivo, in hypoalbuminemic HD patients with the highest OS and inflammation, COP values were also higher than expected for the low albumin levels. The contribution to COP by other prevalent plasma proteins, such as fibrinogen and immunoglobulins was negligible. We imply that the calculation of COP based on albumin levels should be revisited in face of OS and inflammation. Hence, in hypoalbuminemic proteinuric patients with systemic OS and inflammation the assumption of low COP should be verified by its measurements.

Anesthesia Management of Liver Transplantation

Anesthesia for liver transplantation pertains to a continuum of critical care of patients with end-stage liver disease. Hence, anesthesiologists, armed with a comprehensive understanding of pathophysiology and physiologic effects of liver transplantation on recipients, are expected to maintain homeostasis of all organ function. Specifically, patients with fulminant hepatic failure develop significant changes in cerebral function, and cerebral perfusion is maintained by monitoring cerebral blood flow and cerebral metabolic rate of oxygen, and intracranial pressure. Hyperdynamic circulation is challenged by the postreperfusion syndrome, which may lead to cardiovascular collapse. The goal of circulatory support is to maintain tissue perfusion via optimal preload, contractility, and heart rate using the guidance of right-heart catheterization and transesophageal echocardiography. Portopulmonary hypertension and hepatopulmonary syndrome have high morbidity and mortality, and they should be properly evaluated preoperatively. Major bleeding is a common occurrence, and euvolemia is maintained using a rapid infusion device. Pre-existing coagulopathy is compounded by dilution, fibrinolysis, heparin effect, and excessive activation. It is treated using selective component or pharmacologic therapy based on the viscoelastic properties of whole blood. Hypocalcemia and hyperkalemia from massive transfusion, lack of hepatic function, and the postreperfusion syndrome should be aggressively treated. Close communication between all parties involved in liver transplantation is also equally valuable in achieving a successful outcome.

Ceruloplasmin and other copper binding components of blood plasma and their functions: an update

We know that blood plasma contains many proteins and also other components that bind copper. The largest contributor to copper in the plasma is ceruloplasmin, which accounts for 40-70 percent. Apart from ceruloplasmin and albumin, most of these components have not been studied extensively, and even for ceruloplasmin and albumin, much remains to be discovered. New components with new functions, and new functions of known components are emerging, some warranting reconsideration of earlier findings. The author's laboratory has been actively involved in research on this topic. This review summarizes and updates our knowledge of the nature and functions of ceruloplasmin and the other known and emerging copper-containing molecules (principally proteins) in this fluid, to better understand how they contribute to copper homeostasis and consider their potential significance to health and disease.

Open-Porous Hydroxyapatite Scaffolds for Three-Dimensional Culture of Human Adult Liver Cells

Liver cell culture within three-dimensional structures provides an improved culture system for various applications in basic research, pharmacological screening, and implantable or extracorporeal liver support. Biodegradable calcium-based scaffolds in such systems could enhance liver cell functionality by providing endothelial and hepatic cell support through locally elevated calcium levels, increased surface area for cell attachment, and allowing three-dimensional tissue restructuring. Open-porous hydroxyapatite scaffolds were fabricated and seeded with primary adult human liver cells, which were embedded within or without gels of extracellular matrix protein collagen-1 or hyaluronan. Metabolic functions were assessed after 5, 15, and 28 days. Longer-term cultures exhibited highest cell numbers and liver specific gene expression when cultured on hydroxyapatite scaffolds in collagen-1. Endothelial gene expression was induced in cells cultured on scaffolds without extracellular matrix proteins. Hydroxyapatite induced gene expression for cytokeratin-19 when cells were cultured in collagen-1 gel while culture in hyaluronan increased cytokeratin-19 gene expression independent of the use of scaffold in long-term culture. The implementation of hydroxyapatite composites with extracellular matrices affected liver cell cultures and cell differentiation depending on the type of matrix protein and the presence of a scaffold. The hydroxyapatite scaffolds enable scale-up of hepatic three-dimensional culture models for regenerative medicine applications.

Insulin Is Required to Maintain Albumin Expression by Inhibiting Forkhead Box O1 Protein

Diabetes is accompanied by dysregulation of glucose, lipid, and protein metabolism. In recent years, much effort has been spent on understanding how insulin regulates glucose and lipid metabolism, whereas the effect of insulin on protein metabolism has received less attention. In diabetes, hepatic production of serum albumin decreases, and it has been long established that insulin positively controls albumin gene expression. In this study, we used a genetic approach in mice to identify the mechanism by which insulin regulates albumin gene transcription. Albumin expression was decreased significantly in livers with insulin signaling disrupted by ablation of the insulin receptor or Akt. Concomitant deletion of Forkhead Box O1 (Foxo1) in these livers rescued the decreased albumin secretion. Furthermore, activation of Foxo1 in the liver is sufficient to suppress albumin expression. These results suggest that Foxo1 acts as a repressor of albumin expression.

Long-term maintenance of a microfluidic 3D human liver sinusoid

The development of long-term human organotypic liver-on-a-chip models for successful prediction of toxic response is one of the most important and urgent goals of the NIH/DARPA's initiative to replicate and replace chronic and acute drug testing in animals. For this purpose, we developed a microfluidic chip that consists of two microfluidic chambers separated by a porous membrane. The aim of this communication is to demonstrate the recapitulation of a liver sinusoid-on-a-chip, using human cells only for a period of 28 days. Using a step-by-step method for building a 3D microtissue on-a-chip, we demonstrate that an organotypic in vitro model that reassembles the liver sinusoid microarchitecture can be maintained successfully for a period of 28 days. In addition, higher albumin synthesis (synthetic) and urea excretion (detoxification) were observed under flow compared to static cultures. This human liver-on-a-chip should be further evaluated in drug-related studies.

Role of transcription factor CCAAT/enhancer-binding protein alpha in human fetal liver cell types in vitro

AIM

The transcription factor CCAAT/enhancer-binding protein alpha (C/EBPα) has been shown to play an important role in liver development, cell proliferation and differentiation. It is, however, largely unknown if C/EBPα regulates cell differentiation and proliferation differently in the diverse cell types of the human liver. We investigated the role of C/EBPα in primary human fetal liver cells and liver cell subpopulations in vitro using a 3-D perfusion bioreactor as an advanced in vivo-like human organ culture model.

METHODS

Human fetal liver cells were investigated in vitro. C/EBPα gene expression was knocked down using siRNA or overexpressed by plasmid transfection. Cell type-specific gene expression was studied, cell populations and their proliferation were investigated, and metabolic parameters were analyzed.

RESULTS

When C/EBPα gene expression was knocked down, we observed a significantly reduced expression of typical endothelial, hematopoietic and mesenchymal genes such as CD31, vWF, CD90, CD45 and α-smooth muscle actin in fetal cells. The intracellular expression of hepatic proteins and genes for liver-specific serum proteins α-fetoprotein and albumin were reduced, their protein secretion was increased. Fetal endothelial cell numbers were reduced and hepatoblast numbers were increased. C/EBPα overexpression in fetal cells resulted in increased endothelial numbers, but did not affect mesenchymal cell types or hepatoblasts.

CONCLUSION

We demonstrated that the effects of C/EBPα are specific for the different human fetal liver cell types, using an advanced 3-D perfusion bioreactor as a human in vivo-like model.

Low dose albumin for the prevention of renal impairment following large volume paracentesis in cirrhosis

OBJECTIVES

To evaluate the effect of low dose Albumin i.e. 4 grams per litre of ascitic fluid after large volume paracentesis (LVP) for the prevention of paracentesis induced circulatory dysfunction (PICD) related renal impairment in cirrhosis.

METHODS

Case records of all patients with cirrhosis who underwent LVP from January 12(th), 2011 till December 29(th), 2013 were reviewed. Patients were excluded if they had spontaneous bacterial peritonitis, creatinine >1.5 mg/dl, hepatoma or if volume of ascitic fluid removed was <5 litres. Data including age, gender, cause of cirrhosis, CTP score and volume of ascitic fluid drained were noted. In addition serum creatinine and serum sodium at baseline and one week post paracentesis were recorded.

RESULTS

Two hundred and fourteen patients with cirrhosis underwent LVP during the study period. One hundred and thirty nine patients met the inclusion criteria and were analyzed. Patients were divided into two groups based on the amount of albumin given. The amount of albumin given was 25 grams and 50 grams while the volume of ascitic fluid removed were 6.2±1 litres and 10.4±1.5 litres in groups A and B respectively. One hundred and eight patients were in group A while thirty one patients were in group B respectively. Both groups received albumin at a dose of 4 grams per litre of ascitic fluid removed. Mean age in both groups were 53 years. Hepatitis C was the commonest etiology in both the groups, followed by Hepatitis B. More than 70% patients in both the groups were in child class C. Serum creatinine at baseline and one week post LVP was 1.04±0.24 mg/dl and 1.07±0.35 mg/dl in GROUP A while 1.11±0.23 mg/dl and 1.41±0.94 mg/dl in GROUP B. (P value 0.35). Similarly, serum sodium at baseline and one week post LVP was 130 ±5.6 meq/lit and 129.6±5.9 meq/lit in GROUP A while 127.6±5.8 meq/lit and 128±6.2 meq/lit in GROUP B respectively. (P value 0.14).

CONCLUSION

This study suggests that 4 grams of albumin per litre of ascitic fluid drained is effective in preventing the PICD related renal impairment following large volume paracentesis in cirrhosis.

Significance of technetium-99m human serum albumin diethylenetriamine pentaacetic acid scintigraphy in patients with nephrotic syndrome

It is thought that a large amount of albumin leaking from the glomerulus in nephrotic syndrome (NS) is reabsorbed at the proximal tubule and catabolized. Therefore, it is possible the final quantity of urinary protein does not always reflect the amount of leakage of protein from the glomerulus. We experienced two cases without nephrotic range proteinuria thought to involve hypoproteinemia due to the same pathophysiology as NS. On these patients, we performed protein leakage scintigraphy with technetium-99m human serum albumin diethylenetriamine pentaacetic acid (^99mTc-HSAD) to exclude a diagnosis of protein-losing gastroenteropathy and observed diffuse positive accumulation in the kidneys with more intense uptake in the kidney than the liver on the anterior view 24 hours after ^99mTc-HSAD administration. In healthy adults intravenously given ^99mTc-HSAD, the same dynamics are observed as in albumin metabolism, and the organ radioactivity of the liver and kidneys after 24 hours is equal. Therefore, we thought it was possible that the renal uptake 24 hours after ^99mTc-HSAD administration was a characteristic finding of NS. In order to confirm it, the subjects were divided into two groups: the NS group (n = 10) and the non-NS group (n = 7). We defined more intense uptake in the kidney than the liver on the anterior view 24 hours after ^99mTc-HSAD administration as Dense Kidney (+). Furthermore, we designed regions of interest in the right and left kidneys and liver on anterior and posterior images, then calculated the kidney-liver ratio. Nine of the ten patients had Dense Kidney (+) in the NS group, compared to none in the non-NS group. And the kidney-liver ratio was significantly higher in the NS group than in the non-NS group on each view in the bilateral kidneys. In conclusion, our results suggest that the renal uptake 24 hours after ^99mTc-HSAD administration is a characteristic finding of NS.

Induction of Hepatic and Endothelial Differentiation by Perfusion in a Three-Dimensional Cell Culture Model of Human Fetal Liver

The development of functional engineered tissue constructs depends on high cell densities and appropriate vascularization. In this study we implemented a four-compartment three-dimensional perfusion bioreactor culture model for studying the effects of medium perfusion on endothelial, hepatic, and hematopoietic cell populations of primary human fetal liver in an in vivo-like environment. Human fetal liver cells were cultured in bioreactors configured to provide either perfusion or diffusion conditions. Metabolic activities of the cultures were monitored daily by measuring glucose consumption and lactate production. Cell viability during culture was analyzed by lactate dehydrogenase activity. Hepatic functionality was determined by the release of albumin and alpha-fetoprotein (AFP) in culture medium samples. After 4 days of culture, cells were analyzed for the expression of a variety of endothelial, hepatic, and hematopoietic genes, as well as the surface marker expression of CD31 and CD34 in flow cytometry. We found that medium perfusion increased the gene expression of endothelial markers such as CD31, von Willebrand factor (vWF), CD140b, CD309, and CD144 while decreasing the gene expression of the erythrocyte-surface marker CD235a. Hepatic differentiation was promoted under perfusion conditions as demonstrated by lower AFP and higher albumin secretion compared with cultures not exposed to medium perfusion. Additionally, cultures exposed to medium perfusion gave higher rates of glucose consumption and lactate production, indicating increased metabolic activity. In conclusion, high-density bioreactors configured to provide constant medium perfusion significantly induced hepatic and endothelial cell differentiation and provided improved conditions for the culture of human fetal liver cells compared with cultures without perfusion.

Biochemical, histological, and memory impairment effects of chronic copper toxicity: a model for non-Wilsonian brain copper toxicosis in Wistar rat

Animal models of copper toxicosis rarely exhibit neurological impairments and increased brain copper accumulation impeding the development of novel therapeutic approaches to treat neurodegenerative diseases having high brain Cu content. The aim of this study was to investigate the effects of intraperitoneally injected copper lactate (0.15 mg Cu/100 g body weight) daily for 90 days on copper and zinc levels in the liver and hippocampus, on biochemical parameters, and on neurobehavioral functions (by Morris water maze) of male Wistar rats. Copper-administered animals exhibited significantly decreased serum acetylcholinesterase (AChE) activity and impaired neuromuscular coordination and spatial memory compared to control rats. Copper-intoxicated rats showed significant increase in liver and hippocampus copper content (99.1 and 73 % increase, respectively), 40.7 % reduction in hepatic zinc content, and interestingly, 77.1 % increase in hippocampus zinc content with concomitant increase in copper and zinc levels in serum and urine compared to control rats. Massive grade 4 copper depositions and grade 1 copper-associated protein in hepatocytes of copper-intoxicated rats were substantiated by rhodanine and orcein stains, respectively. Copper-intoxicated rats demonstrated swelling and increase in the number of astrocytes and copper deposition in the choroid plexus, with degenerated neurons showing pyknotic nuclei and dense eosinophilic cytoplasm. In conclusion, the present study shows the first evidence in vivo that chronic copper toxicity causes impaired spatial memory and neuromuscular coordination, swelling of astrocytes, decreased serum AChE activity, copper deposition in the choroid plexus, neuronal degeneration, and augmented levels of copper and zinc in the hippocampus of male Wistar rats.

Regulation of brain iron and copper homeostasis by brain barrier systems: implication in neurodegenerative diseases

Iron (Fe) and copper (Cu) are essential to neuronal function; excess or deficiency of either is known to underlie the pathoetiology of several commonly known neurodegenerative disorders. This delicate balance of Fe and Cu in the central milieu is maintained by the brain barrier systems, i.e., the blood-brain barrier (BBB) between the blood and brain interstitial fluid and the blood-cerebrospinal fluid barrier (BCB) between the blood and cerebrospinal fluid (CSF). This review provides a concise description on the structural and functional characteristics of the brain barrier systems. Current understanding of Fe and Cu transport across the brain barriers is thoroughly examined, with major focuses on whether the BBB and BCB coordinate the direction of Fe and Cu fluxes between the blood and brain/CSF. In particular, the mechanism by which pertinent metal transporters in the barriers, such as the transferrin receptor (TfR), divalent metal transporter (DMT1), copper transporter (CTR1), ATP7A/B, and ferroportin (FPN), regulate metal movement across the barriers is explored. Finally, the detrimental consequences of dysfunctional metal transport by brain barriers, as a result of endogenous disorders or exogenous insults, are discussed. Understanding the regulation of Fe and Cu homeostasis in the central nervous system aids in the design of new drugs targeted on the regulatory proteins at the brain barriers for the treatment of metal's deficiency or overload-related neurological diseases.

Abnormal serum thyroid hormones concentration with healthy functional gland: a review on the metabolic role of thyroid hormones transporter proteins

Laboratory findings can definitely help the patients not to enter into status, where the damage might be happen due to a miss-diagnosis based on clinical assessment alone. The secondary disease accompanied with thyroid patients should also carefully check out due to the interference which some diseases can cause in the amount of serum thyroid hormone, particularly the free thyroxin. The dilemma over thyroid clinical diagnosis occur due to variation on serum thyroid hormone which initiated by other non-thyroidal disorders which can play an important roles in metabolic disorders of thyroid hormone due to the alteration which occur on the serum level of thyroid hormone transporter proteins. The majority of serum thyroid hormones of up to 95-99% are bound to the carrier proteins mainly to Thyroxin-Binding Globulins (TBG), some transthyretin already known as pre-albumin and albumin which are all synthesis in the liver and any modification which alter their production may alter the status of thyroid hormones. It seems TBG, transthyretin and albumin carries 75, 20, 5% of thyroid hormones within blood circulation, respectively. The dilemma facing the thyroid hormones following disruption of thyroid hormone transporter protein synthesis originate from this fact that any alteration of these protein contribute to the alteration of total thyroid and free serum thyroid hormones which are in fact the biologically active form of thyroid hormones. The subsequent of latter implication result in miss-understanding and miss-diagnosis of thyroid function tests, with possible wrongly thyroid clinical care, followed by undesired therapy of otherwise healthy thyroid.

[Ascites, hepatorenal syndrome and spontaneous bacterial peritonitis in patients with portal hypertension]

Ascites, hepatic encephalopathy and variceal hemorrhage are three major complications of portal hypertension. The diagnostic evaluation of ascites involves an assessment of its etiology by determining the serum-ascites albumin gradient and the exclusion of spontaneous bacterial peritonitis. Ascites is primarily related to an inability to excrete an adequate amount of sodium into urine, leading to a positive sodium balance. Sodium restriction and diuretic therapy are keys of ascites control. But, with the case of refractory ascites, large volume paracentesis and transjugular portosystemic shunts are required. In hepatorenal syndrome, splanchnic vasodilatation with reduction in effective arterial volume causes intense renal vasoconstriction. Splanchnic and/or peripheral vasoconstrictors with albumin infusion, and renal replacement therapy are only bridging therapy. Liver transplantation is the only definitive modality of improving the long term prognosis.

Three-dimensional perfusion bioreactor culture supports differentiation of human fetal liver cells

The ability of human fetal liver cells to survive, expand, and form functional tissue in vitro is of high interest for the development of bioartificial extracorporeal liver support systems, liver cell transplantation therapies, and pharmacologic models. Conventional static two-dimensional culture models seem to be inadequate tools. We focus on dynamic three-dimensional perfusion technologies and developed a scaled-down bioreactor, providing decentralized mass exchange with integral oxygenation. Human fetal liver cells were embedded in a hyaluronan hydrogel within the capillary system to mimic an in vivo matrix and perfusion environment. Metabolic performance was monitored daily, including glucose consumption, lactate dehydrogenase activity, and secretion of alpha-fetoprotein and albumin. At culture termination cells were analyzed for proliferation and liver-specific lineage-dependent cytochrome P450 (CYP3A4/3A7) gene expression. Occurrence of hepatic differentiation in bioreactor cultures was demonstrated by a strong increase in CYP3A4/3A7 gene expression ratio, lower alpha-fetoprotein, and higher albumin secretion than in conventional Petri dish controls. Cells in bioreactors formed three-dimensional structures. Viability of cells was higher in bioreactors than in control cultures. In conclusion, the culture model implementing three-dimensionality, constant perfusion, and integral oxygenation in combination with a hyaluronan hydrogel provides superior conditions for liver cell survival and differentiation compared to conventional culture.

Balancing volume resuscitation and ascites management in cirrhosis

PURPOSE OF REVIEW

Patients with cirrhosis have total extracellular fluid overload but central effective circulating hypovolaemia. The resulting neurohumoral compensatory response favours the accumulation of fluids into the peritoneal cavity (ascites) and may hinder renal perfusion (hepatorenal syndrome). Their deranged systemic haemodynamics (hyperdynamic circulatory syndrome) is characterized by elevated cardiac output with decreased systemic vascular resistance and low blood pressure.

RECENT FINDINGS

Molecular and biological mechanisms determining cirrhosis-induced haemodynamic alterations are progressively being elucidated. The need for a goal-directed assessment of volume resuscitation (especially with volumetric techniques) in patients with cirrhosis is becoming more and more evident. The role of fluid expansion with albumin and the use of splanchnic vasopressors in a variety of cirrhosis-related conditions has recently been investigated.

SUMMARY

The response to fluid loading in patients with advanced cirrhosis is abnormal, primarily resulting in expansion of their noncentral blood volume compartment. Colloid solutions, in particular albumin, are best used in these patients. Albumin may be effective in preventing the haemodynamic derangements associated with large-volume paracentesis (paracentesis-induced circulatory dysfunction), in preventing renal failure during spontaneous bacterial peritonitis and, in association with splanchnic vasopressors, in caring for patients with the hepatorenal syndrome.

Adaptations to high-intensity intermittent exercise in rodents

In humans, exercise-induced plasma volume (PV) expansion is typically associated with an increase in plasma albumin content, due in part to an increase in hepatic albumin synthesis. We tested the ability of a 12-day high-intensity intermittent exercise protocol to induce an increase in PV in rodents. Since albumin synthesis is transcriptionally regulated, we tested the hypothesis that exercise training would induce an increase in hepatic albumin gene expression. Fifty adult male Sprague-Dawley rats weighing between 245 and 350 g were randomly assigned to one of five groups: cage control (CC), sham exercise (sham), continuous moderate-intensity exercise training (MI), high-intensity intermittent exercise training (HI), or a single day of HI training (1-HI). Twenty-four hours after the last training session, rats were anesthetized. PV was determined, and the liver was removed, flash frozen, and stored for later analysis. Citrate synthase (CS) activity of the red quadriceps muscle, a marker of aerobic adaptation, increased with training (MI and HI) and in response to 1-HI (P < 0.05). We did not see a significant exercise-induced PV expansion as PV averaged 23.6 +/- 2.7 ml/kg body wt in the CC group and 26.6 +/- 1.3 ml/kg body wt in the HI group (P > 0.05). However, hepatic albumin mRNA expression, as determined by real-time PCR, increased 2.9 +/- 0.4- and 4.1 +/- 0.4-fold after MI and HI, respectively, compared with CC. A single bout of HI (1-HI) did not alter hepatic albumin mRNA expression. These data demonstrate an increase in both CS activity and hepatic albumin gene expression with 12 days of aerobic exercise training in the rodent with a rapid (within 24 h) adaptation in the skeletal muscle to high-intensity intermittent exercise.

In vitro analysis of a hepatic device with intrinsic microvascular-based channels

A novel microfluidics-based bilayer device with a discrete parenchymal chamber modeled upon hepatic organ architecture is described. The microfluidics network was designed using computational models to provide appropriate flow behavior based on physiological data from human microvasculature. Patterned silicon wafer molds were used to generate films with the vascular-based microfluidics network design and parenchymal chamber by soft lithography. The assembled device harbors hepatocytes behind a nanoporous membrane that permits transport of metabolites and small proteins while protecting them from the effects of shear stress. The device can sustain both human hepatoma cells and primary rat hepatocytes by continuous in vitro perfusion of medium, allowing proliferation and maintaining hepatic functions such as serum protein synthesis and metabolism. The design and fabrication processes are scalable, enabling the device concept to serve as both a platform technology for drug discovery and toxicity, and for the continuing development of an improved liver-assist device.

Copper transport to the brain by the blood-brain barrier and blood-CSF barrier

The mechanism of copper (Cu) transport into the brain is unclear. This study evaluated the main species and route of Cu transport into the brain using in situ brain perfusion technique, and assessed the levels of mRNA encoding Cu transporters using real time RT-PCR. Free (64)Cu uptake in rat choroid plexus (CP), where the blood-cerebrospinal fluid barrier (BCB) is primarily located, is about 50 and 1000 times higher than (64)Cu-albumin and (64)Cu-ceruloplasmin uptake, respectively. The unidirectional transport rate constants (K(in)) for Cu in the CP and brain capillaries of the blood-brain barrier (BBB) were 1034 and 319 microl/s/g, respectively, while K(in) in CSF and capillary-depleted parenchyma were much reduced, 0.8 and 112 microl/s/g, respectively. The K(in) in cerebellum was significantly lower than that in hippocampus. The mRNAs encoding Cu transporter-1 (Ctr1) and ATP7A were higher in the CP than those in brain capillaries and parenchyma, whereas ATP7B mRNA was higher in brain capillaries than those in the CP and brain parenchyma. Taken together, these data suggest that the expression of Cu transporters is higher in brain barriers than in brain parenchyma; the Cu transport into the brain is mainly achieved through the BBB as a free Cu ion and the BCB may serve as a main regulatory site of Cu in the CSF.

Removal of ascites up to 7.5 liters on one occasion and 45 liters in total may be safe in patients with severe ovarian hyperstimulation syndrome

Ovarian hyperstimulation syndrome (OHSS) is a serious and potentially lethal complication of ovulation induction. We report herein a case with OHSS treated by serial vaginal paracentesis. A 31-year-old patient was hospitalized due to severe OHSS after in vitro fertilization (IVF)-embryo transfer. Transvaginal drainage was performed with a standard 17-gauge IVF needle connected to a vacuum pump through a drainage set in nine courses. We removed 45 liters of ascitic fluid in total and 7.5 liters of ascitic fluid in one course, leading to improvement of the patient's condition and laboratory parameters. In conclusion, removal of ascites up to 7.5 liters on one occasion and 45 liters in total by serial vaginal paracentesis may be performed in patients with severe OHSS.

Novel Method to Examine Hepatocyte-Specific Gene Expression in a Functional Coculture System

To mimic native tissue function, coculture systems are an extremely useful model. In many cases, differentiated functions can be maintained only through the interactions of various cell types. Therefore, methods for examining the interactions between cocultured cells are necessary. The assessment of cell-to-cell cross-talk at the level of gene expression is one such method to examine interactions between different cell types. However, it is generally difficult to determine the gene expression of specific cell types in coculture without first separating cell populations. To overcome these obstacles, we have established a novel method to determine gene expression levels of a targeted cell population in coculture, using species-specific primers. With this approach, we were able to determine hepatocyte-specific gene expression of Fao cells (a rat hepatocyte cell line) in culture with human umbilical vein endothelial cells (HUVECs). Expression of both albumin and apolipoprotein A-I (apoA-I) increased time dependently for 10 days and maintained significantly higher expression in the coculture system as compared with isolated Fao cells. This indicates that hepatocyte function increased gradually in our coculture system and could be maintained long-term, suggesting that the construction of mature cell-to-cell communication between the two cell lines required a considerable amount of time. The expression of HNF-4 and HNF-1alpha, which are liver-enriched transcription factors, did not differ between the monolayer and cocultured Fao cells, suggesting that expression of HNF-4 and HNF-1alpha was not responsible for the increased expression albumin and apoA-I. Our findings suggest that this novel method for the detection of gene expression of targeted cell populations can be a useful tool in determining the molecular mechanisms that regulate communication between different cell types.

Expression of apolipoprotein AI mRNA in peripheral white blood cells of patients with alcoholic liver disease

Because (i) changes in plasma and liver mRNA of apolipoprotein (apo) AI have been observed in patients with alcoholic liver disease, (ii) apo AI mRNA can be induced in non-hepatic tissues, and (iii) apolipoproteins expression is influenced by plasma colloid osmotic pressure (P(CO)) and viscosity (eta), we analyzed the Apo AI mRNA expression in the peripheral white blood cells (PWBC), P(CO), and eta in control volunteers (C), patients with liver cirrhosis (LC), and cirrhotic patients with superimposed alcoholic hepatitis (LC+AH). We found that apo AI mRNA is expressed in the PWBC in 20% of C and it is induced 1.5 fold in 66.6% of LC and 1.95 fold in 85% of LC+AH. A significant decrease of P(CO) in LC and LC + AH (14.8 +/- 2.4 and 16.2 +/- 2.4 mm Hg, respectively) compared to C (27.9 +/- 2 mm Hg) was observed. By contrast, eta was mildly increased from 1.7389 +/- 0.07 in C to 1.8022 +/- 0.154 in LC and 1.9030 +/- 0.177 in LC+AH. No significant correlation was found between P(CO) and eta with apo AI mRNA but with lipid profile. In conclusion, apo AI mRNA expression in PWBC is associated to liver disease severity and could be an indirect indicator of alcoholic liver damage.

The albumin controversy

There are relatively few studies of albumin use in neonates and children, with most showing no consistent benefit compared with the use of crystalloid solutions. Certainly, albumin treatment is not indicated for treatment of hypoalbuminemia alone. Studies also show that albumin is not indicated in neonates for the initial treatment of hypotension, respiratory distress, or partial exchange transfusions. In adults, albumin is not considered to be the initial therapy for hypovolemia, burn injury, or nutritional supplementation. Based on the evidence, albumin should be used rarely in the neonatal ICU. Albumin may be indicated in the treatment of hypovolemia only after crystalloid infusion has failed. In patients with acute hemorrhagic shock, albumin may be used with crystalloids when blood products are not available immediately. Inpatients with acute or continuing losses of albumin and normal capillary permeability and lymphatic function, such as during persistent thoracostomy tube or surgical site drainage, albumin supplementation will prevent the development of hypoalbuminemia, and possibly edema formation. This has not been studied systematically, however. In patients with hypoalbuminemia and increased capillary permeability, albumin supplementation often leads to greater albumin leakage across the capillary membrane, contributing to edema formation without improvement in outcome. As the disease process improves and capillary permeability normalizes, albumin supplementation may accelerate recovery, but long-term benefits of albumin treatment usually cannot be demonstrated. These patients will recover whether or not albumin is administered.

Effects of feeding on albumin synthesis in hypoalbuminemic hemodialysis patients

BACKGROUND

Hypoalbuminemia is a powerful predictor of morbidity and mortality in hemodialysis (HD) patients and results from a reduction in albumin synthesis. It is not known if this is associated with any impairment of the normal response to feeding.

METHODS

Protein turnover and albumin synthesis were measured in the fasting and fed state using a primed constant infusion of L-[1-(13)C]leucine in seven hypoalbuminemic (albumin < or = 36 g/L) HD patients (HHD), seven normoalbuminemic (albumin > or = 40 g/L) HD patients (NHD) and nine age-matched normal controls.

RESULTS

The increase in albumin synthesis on feeding was impaired in HHD patients (fasting 15.0 +/- 1.5 vs. fed 17.7 +/- 2.9%, P = NS) compared to NHD (fasting 13.7 +/- 0.9 vs. fed 17.4 +/- 1.0%, P < 0.05) and controls (fasting 12.9 +/- 0.6 vs. fed 15.2 +/- 0.6%, P < 0.05). In addition, body mass index and percent body fat were significantly (P < 0.05) lower in HHD (20.8 +/- 1.3 kg/m2, 23.4 +/- 2.0%) than NHD (26.7 +/- 1.3 kg/m2, 33.1 +/- 3.2%) or controls (26.2 +/- 1.1 kg/m2, 32.6 +/- 1.8%). There was no difference in dietary protein or energy intake in the three groups.

CONCLUSIONS

There are differences of body composition and protein metabolism in HHD patients that may be related to an impaired metabolic response to feeding.

p53 represses CAAT enhancer-binding protein (C/EBP)-dependent transcription of the albumin gene. A molecular mechanism involved in viral liver infection with implications for hepatocarcinogenesis

p53 is a transcription factor that is activated by genotoxic stress and mediates cell cycle arrest and apoptosis. Here we demonstrate that infection of mouse liver with recombinant E1/E3-deleted adenovirus leads to p53 activation and simultaneously to the down-regulation of albumin gene expression. In vitro transcription assays indicate that transcriptional mechanisms mediated through the albumin promoter are responsible for reduced albumin mRNA levels during viral infection. Albumin expression is maintained in the liver by a combination of liver-enriched transcription factors such as CAAT enhancer-binding protein (C/EBP)alpha and C/EBPbeta. We show that p53 wild type and tumor-derived p53 mutations repress C/EBP-mediated transactivation of the albumin promoter. The binding of C/EBPalpha or -beta to its cognate sequence in the albumin promoter is not inhibited by p53 expression. Deletion analysis and domain swapping experiments show that repression of C/EBPbeta-mediated transactivation is dependent on the N-terminal domain of p53 and the transactivation domain, leucine zipper domain, and the inhibitory domain II (amino acids 163-191) of C/EBPbeta. Our results provide a molecular explanation for the p53-mediated down-regulation of liver-specific gene expression after viral infection. Additionally, as overexpression of p53 mutants is frequently found in undifferentiated hepatocellular carcinomas, the same mechanisms may contribute to the lack of liver-specific gene transcription in these tumors.

Serum albumin: touchstone or totem?

A decrease in serum albumin concentrations is an almost inevitable finding in disease states, and is primarily mediated in the acute phase by alterations in vascular permeability and redistribution. This change is not disease specific but marked changes that persist are generally associated with a poorer prognosis. Critical appraisal of long-standing practices and the availability of alternative colloid solutions have led to a reduction in albumin replacement therapy, and a widespread tolerance of lower albumin concentrations in patients. The factors determining serum albumin concentrations, their measurement and the implications of hypoalbuminaemia are reviewed. The clinical value of serum albumin measurement is discussed.

Cell volume regulates liver phosphoenolpyruvate carboxykinase and fructose-1,6-bisphosphatase genes

Hypertonic-induced cell shrinkage increases glucose release in H-4-II-E rat hepatoma cells. This is paralleled by a concomitant increase in the mRNA levels of the rate-limiting enzymes of the pathway of gluconeogenesis, phosphoenolpyruvate carboxykinase (PCK) and fructose-1,6-bisphosphatase (FBP), of seven- and fivefold, respectively. In contrast, hypotonic-induced swelling of the cells results in a transient decrease in PCK and FBP mRNAs to 15% and 39% of control levels. The antagonistic effects of hyper- and hypotonicity mimic the counteracting effects of adenosine 3',5'-cyclic monophosphate (cAMP) and insulin on PCK and FBP mRNA levels. The hypertonic-induced increase in mRNA levels is due to an enhanced transcriptional rate, whereas the decrease in mRNAs caused by hypotonicity results from a decrease in transcription as well as mRNA stability. The inductive effect of hypertonicity does not require ongoing protein synthesis and acts independently of the cAMP-dependent protein kinase and protein kinase C pathways. These results suggest that cell volume changes in liver cells may play an important role in regulating hepatic glucose metabolism by altered gene expression.

Management of adult patients with ascites caused by cirrhosis

Ascites is the most common of the major complications of cirrhosis. The development of ascites is an important landmark in the natural history of cirrhosis and has been proposed as an indication for liver transplantation. The initial evaluation of a patient with ascites should include a history, physical evaluation, and abdominal paracentesis with ascitic fluid analysis. Treatment should consist of abstinence from alcohol, sodium restricted diet, and diuretics. This regimen is effective in approximately 90% of patients. The treatment options for the diuretic-resistant patients include serial therapeutic paracenteses, liver transplantation, and peritoneovenous shunting.