Serum albumin is a specific inhibitor of apoptosis in human endothelial cells

Manual cryopreservation of human alveolar periosteal tissue segments: Effects of pre-culture on recovery rate

Cultured human periosteal sheets constitute a promising grafting material for periodontal tissue regenerative therapy. However, preparation of these sheets usually requires six weeks or longer, and this lengthy commitment and delay limits both clinical applicability and availability. The aim of this study is to develop an efficient, practical, cost-effective cryopreservation method for periosteal tissue segments (PTSs). Human PTSs were aseptically excised from alveolar bone and pre-cultured in Medium 199+10% fetal bovine serum (FBS) for the indicated number of days before they were slowly frozen down to -75°C in a commercial freezing vessel using medium containing 10% dimethyl sulfoxide (Me(2)SO) and various concentrations of FBS. After fast-thawing at 37°C, PTSs were again cultured, and their growth and responses to standard osteogenic induction were evaluated (vs. freshly excised PTSs). Proliferating cells were obtained at the highest levels from cryopreserved PTSs that were pre-cultured for 14 days before freezing. When a concentration of 50% or more FBS was included in the cryopreservation solution, cells migrated out more actively and grew faster. Importantly, osteoinduction up-regulated alkaline phosphatase (ALP) activity and osteoblastic marker mRNAs in cryopreserved PTS-derived sheets just as effectively as it did in native PTS-derived ones. These data suggest that pre-conditioned PTSs can be efficiently cryopreserved in a freezing solution containing high FBS by traditional manual cryopreservation methods without aid of a program freezer or more elaborate equipment.

Alternative complement pathway assessment in patients with atypical HUS

The atypical Hemolytic Uremic Syndrome (aHUS) is a rare thrombotic microangiopathy leading to end stage renal disease in approximately 60% of patients. Over the last decade, a clear link has been demonstrated between this disease and defective complement regulation. The hallmark of the aHUS is the association with mutations in complement alternative pathway genes. Endothelial damage is related to complement dysregulation, but the exact mechanism is just starting to be elucidated. Screening for and characterization of mutations in the components of the C3 convertase (C3 and FB) or its regulators (FH, FI, MCP, and Thrombomodulin) or anti-FH antibodies has become an indispensable part of the disease's diagnostic. This review will initially summarize current knowledge on the understanding of complement activation and regulation, followed by a description on the genetic analysis as well as the methods used for complement protein quantification. Another part of this review will focus on the mechanisms of action of aHUS-associated mutations. We will emphasize on when and why some mutations lead to protein deficiency, while others result in - to dysfunctional but normally expressed proteins. Finally, we will discuss how the therapy of aHUS patients can be modified according to the functional consequences of each particular genetic defect.

Low serum albumin levels and in-hospital adverse outcomes in acute coronary syndrome

Epidemiological studies have demonstrated an association between low serum albumin levels and coronary heart disease and mortality. Nevertheless, the impact of a low serum albumin level during acute coronary syndrome has not yet been established. The aim of the present study was to investigate whether low serum albumin levels are associated with adverse outcomes in acute coronary syndrome. We enrolled 82 consecutive patients with acute coronary syndrome from whom venous blood for serum albumin measurement was drawn immediately upon hospital admission. Thirty-five patients had a low albumin level (hypoalbuminemia) and 47 had a normal albumin level (normoalbuminemia). In-hospital adverse outcomes (death, acute heart failure, cardiogenic shock, and reinfarction) were recorded during hospitalization in the intensive coronary care unit. The results of our study showed that the incidence of in-hospital adverse outcomes was 43%, with death occurring in 8 patients (10%). In-hospital adverse outcomes occurred more frequently in patients presenting with hypoalbuminemia, whereas mortality did not differ significantly. Univariate analysis showed that hypoalbuminemia was associated with a 2.8-fold greater risk of developing adverse outcomes. This risk was greater in the subgroup of NSTEACS (5.4-fold increased risk), but not in those with STEMI. Adjustment with other covariates revealed that hypoalbuminemia did not predict independently in-hospital adverse outcomes. It interacted with other predictors, especially Killip class II-IV, which was consistently an independent predictor of in-hospital adverse outcomes.

Albumin level and stroke. Potential association between lower albumin level and cardioembolic aetiology

BACKGROUND

Lower level of albumin was related to worse prognosis of stroke and clinical trials showed that albumin therapy reduced mortality. However, stroke is heterogeneous and differences in the baseline concentration of albumin among subtypes of stroke were not assessed. The aim was to assess albumin level in patients with ischemic stroke classified by mechanism.

METHODS

Prospective controlled clinical study, including 200 patients with ischemic stroke and 50 controls. Patients were classified following Trial of ORG 10172 in Acute Stroke Treatment criteria. Plasma levels of albumin, fibrinogen, D-dimer, and C-reactive protein were assessed during 48 hr after admission. The National Institutes of Health Stroke Scale (NIHSS) on admission, in-hospital mortality, and Rankin score on discharge were recorded. Dependence was defined as mRS > 2.

RESULTS

Patients with cardioembolic stroke showed significantly higher D-dimer and lower albumin. Mortality was related to higher NIHSS, higher D-dimer, lower albumin, and cardioembolic aetiology. Dependence was strongly related to lower albumin and higher NIHSS. LOGISTIC REGRESSION: The cardioembolic aetiology (OR 0.101, 95% CI 0.010-1.007, p = .051) and the higher NIHSS score (OR 0.871, 95% CI 0.758-1.002, p = .053) were related to mortality; NIHSS (OR 1.560, 95% CI 1.323-1.838, p < .0001) and older age (OR 1.052, 95% CI 1.012-1.093, p = .010) were independently related to dependence.

DISCUSSION

Patients with cardioembolic stroke showed lower albumin and higher risk of mortality than non-cardioembolic ones. Lower mean level of albumin was related to mortality and dependence in all patients. Reduced albumin may be a marker of chronic systemic inflammation, which may be the mechanism for cardiopathy and bad outcome of stroke. In addition, direct effects on ischemic tissue were suggested in experimental models.

Propranolol suppresses angiogenesis in vitro: inhibition of proliferation, migration, and differentiation of endothelial cells

Propranolol, a non-selective β-adrenergic blocking drug, was recently reported to control the growth of hemangiomas, the most common vascular tumor of infancy. However, the mechanisms involved in this effect remain unknown. Here, we demonstrate that propranolol dose-dependently inhibited growth factor-induced proliferation of cultured human umbilical vein endothelial cells (HUVECs) through a G₀/G₁ phase cell cycle arrest. This was correlated to decreased cyclin D1, cyclin D3, and cyclin-dependent kinase CDK6 protein levels, while increases in the CDK inhibitors p15(INK4B), p21(WAF1/Cip1) and p27(Kip1) were observed. Chemotactic motility and differentiation of HUVECs into capillary-like tubular structures in Matrigel were also inhibited by propranolol. Furthermore, inhibition by propranolol of vascular endothelial growth factor (VEGF)-induced tyrosine phosphorylation of VEGF receptor-2 lead to inhibition of downstream signaling such as the activation of the extracellular signal-regulated kinase-1/2 and the secretion of the extracellular matrix degrading enzyme MMP-2. Taken together, these results demonstrate that propranolol interferes with several essential steps of neovascularization and opens up novel therapeutic opportunities for the use of β-blockers in the treatment of angiogenesis-dependent human diseases.

Resuscitation with hydroxyethyl starch solution prevents bone marrow mononuclear apoptosis in a rat trauma-hemorrhagic shock model

BACKGROUND

: Trauma-hemorrhagic shock (T/HS) has been associated with multiorgan dysfunction, including bone marrow failure. This study examined apoptosis and morphologic alterations in bone marrow mononuclear cells (BMMNCs) with different volume therapies after T/HS.

METHODS

: T/HS was induced in groups of male Sprague-Dawley rats through a fracture of the left femur and continual bleeding for 30 minutes, followed by resuscitation with Ringer's lactate solution (RL), 6% hydroxyethyl starch solution (HES), or 5% albumin (ALB). Mean arterial blood pressure was monitored during the T/HS and resuscitation, and the impacts of various resuscitative fluids on apoptosis and morphology of BMMNCs at 24 hours and 48 hours after resuscitation were examined using flow cytometry, transferase-mediated dUTP nick-end labeling assay, and hematoxylin and eosin staining.

RESULTS

: Fluctuations in mean arterial blood pressure were homogenous among the three treatment groups. The percentage of early BMMNC apoptosis increased significantly at 24 hours and 48 hours (24.65% +/- 5.41% and 29.09% +/- 2.07%, respectively; p < 0.05), and the percentage of late BMMNC apoptosis increased to 13.43% +/- 2.82% (p < 0.05) at 48 hours in the T/HS + RL group. In contrast, resuscitation with HES alone dramatically attenuated the apoptosis. Resuscitation with ALB alleviated BMMNC apoptosis, except for late apoptosis at 48 hours. A greater number of apoptotic BMMNCs as well as morphologic alterations were shown using the transferase-mediated dUTP nick-end labeling assay and hematoxylin and eosin stain in the T/HS + RL group than in the HES or ALB groups.

CONCLUSION

: Intravascular volume replacement with HES showed prevention of BMMNC apoptosis at first 48 hours after T/HS compared with RL and ALB. These findings provide new insights into the intervention mechanism of HES on T/HS-related multiorgan dysfunction.

Vascularity during wound maturation correlates with fragmentation of serum albumin but not ceruloplasmin, transferrin, or haptoglobin

Reduced vascularity during wound maturation is mediated by endothelial apoptosis. Albumin has an anti-apoptotic activity for endothelium, which increases up to 100-fold on albumin fragmentation (AF). We now report that levels of AF correlate with changing vascularity during wound maturation. Both scarring and adipogenic wound-healing models were established in mice. Western blots of granulation tissue revealed AF concurrent with periods of high vascularity as determined by thin-section microscopy, with reduced AF on wound maturation (p<0.02). In profiling AF, the levels of 27.5 and 39 kDa fragments were reduced on maturation of both scarring and adipogenic wounds (p<0.005), as were the levels of an additional 17.5 kDa fragment prominent only in adipogenic wounds (p<0.001). A 49 kDa albumin fragment was found to be reduced during maturation of scarring (p<0.001) but not adipogenic wounds. For comparison, we probed for transferrin, ceruloplasmin, and haptoglobin fragmentation on the basis that like albumin, these are considered acute-phase transport proteins. Minimal fragmentation of transferrin and ceruloplasmin was seen, along with partial dissociation of haptoglobin subunits, but these did not correlate with AF or vascularity. Our findings are consistent with a role for AF in regulating granulation tissue vascularity during healing.

Transient hypoxia induces ERK-dependent anti-apoptotic cell survival in endothelial cells

Ischemia-induced apoptosis of endothelial cells may contribute to tissue injury, organ failure, and transplantation rejection. However, little is known about survival mechanisms capable to counteract endothelial apoptosis. This study investigated the potential role of an endogenous anti-apoptotic response elicited by transient hypoxia, capable to avert ongoing apoptosis in endothelial cells. Experiments were carried out in three different types of cultured endothelial cells (human umbilical vein, pig aorta, and from rat coronary microvasculature). As a pro-apoptotic challenge endothelial cells were cultured in serum-free medium and subjected to hypoxia for 2 h. We found that transient hypoxia reduced caspase 3 activation within 1 h of hypoxia. Accordingly, the number of apoptotic cells was reduced after 24 h of reoxygenation. This was true for all three cell types analyzed. Analysis of Akt and mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) pathways revealed that hypoxia induced a transient activation of ERK 2 but not of Akt. ERK 2 phosphorylation preceded the phosphorylation of pro-apoptotic molecule Bad at Ser112, an inhibitory phosphorylation site specific for ERK. The protective effects of hypoxia regarding Bad phosphorylation, caspase 3 activation, and apoptosis were abolished by MEK 1/2 inhibitors, PD98059 or UO126, as well as by antisense oligonucleotides directed against ERK 1/2. Furthermore, inhibition of this pathway inhibited hypoxia-induced increase in mitochondrial membrane potential. The present study demonstrates that transient hypoxia induces a novel survival mechanism that protects endothelial cells against apoptosis. This endogenous process involves MEK/ERK-mediated inhibition of the pro-apoptotic molecule Bad and caspase 3.

Serum albumin induces osmotic swelling of rat retinal glial cells

Edema in the ischemic neural tissue develops by increased vascular permeability associated with extravasation of albumin, and by glial swelling. Here, we show that bovine serum albumin acutely administered to slices of the rat retina causes swelling of glial somata under hypoosmotic conditions. The effect of albumin was dose-dependent, with half-maximal and maximal effects at 10 nM and 1 microM, respectively, and was mediated by activation of transforming growth factor-beta receptor type II, oxidative stress, and the production of arachidonic acid and prostaglandins. Albumin-induced glial swelling was prevented by glutamate and purinergic receptor agonists. The data suggest that serum albumin may induce glial swelling in the presence of osmotic gradients.

Evaluation of cardiac function in patients with liver cirrhosis

AIM OF THE STUDY

To study the cardiac function in patients with liver cirrhosis.

METHODS

Thirty patients with liver cirrhosis, referred to as group I (G 1), were selected. They were subdivided according to Child-Pugh classification into 3 groups: A, B, and C. Thirty healthy subjects, referred to as group II (G II), were selected as a control group. All persons were examined by resting ECG, abdominal ultrasound, laboratory tests, and echo-Doppler evaluation of systolic and diastolic functions of both ventricles using 2-D, M-mode, conventional Doppler, and tissue Doppler parameters.

RESULTS

Systolic and diastolic blood pressures were significantly reduced with increased resting HR and CO in G I (p<0.05). The QTc interval was prolonged in G I (0.45±0.03 ms; p<0.001) but EDV, ESV, EF%, and S´ velocity were not significantly different in both study groups for both ventricles. LAD, MPI, LVPWT, and, IVST were significantly increased in G I (p<0.05). E/A and E´/A´ ratios were reversed in G I with increased DT/E for both ventricles (p<0.001). No significant difference was found among Child A, B, C subgroups except for the LAD which was significantly increased in Child C (p<0.05). There was a significant inverse correlation between serum albumin and left ventricular MPI (r=-0.4, p<0.05).

CONCLUSION

Many cardiovascular abnormalities occur in patients with liver cirrhosis that mandate echocardiographic evaluation especially in cases who undergo any procedure which may affect the hemodynamics.

Relevance of albumin in modern critical care medicine

The relevance of albumin administration in the critical care setting remains controversial. We know that albumin has numerous important physiological effects and many potentially beneficial effects in critical illness. We also know that hypoalbuminaemia is common in critically ill patients and is associated with worse outcomes. And we know that routine administration of albumin for fluid resuscitation is not warranted. Albumin may be useful in some patients, especially those with hypoalbuminaemia at risk of complications or those with liver insufficiency. Further studies are needed to clarify what precise role albumin has in today's ICU.

Albumin resuscitation protects against traumatic/hemorrhagic shock-induced lung apoptosis in rats

OBJECTIVE

To determine the effects of albumin administration on lung injury and apoptosis in traumatic/hemorrhagic shock (T/HS) rats.

METHODS

Studies were performed on an in vivo model of spontaneously breathing rats with induced T/HS; the rats were subjected to femur fracture, ischemia for 30 min, and reperfusion for 20 min with Ringer's lactate solution (RS) or 5% (w/v) albumin (ALB), and the left lower lobes of the lungs were resected.

RESULTS

Albumin administered during reperfusion markedly attenuated injury of the lung and decreased the concentration of lactic acid and the number of in situ TdT-mediated dUTP nick-end labelling (TUNEL)-positive cells. Moreover, immunohistochemistry performed 24 h after reperfusion revealed increases in the level of nuclear factor kappaB (NF-kappaB), and phosphorylated p38 mitogen-activated protein kinase (MAPK) in the albumin-untreated group was down-regulated by albumin treatment when compared with the sham rats.

CONCLUSION

Resuscitation with albumin attenuates tissue injury and inhibits T/HS-induced apoptosis in the lung via the p38 MAPK signal transduction pathway that functions to stimulate the activation of NF-kappaB.

Leptin up-regulates the lactogenic effect of prolactin in the bovine mammary gland in vitro

The ability of leptin to up-regulate prolactin action in the mammary gland is well established. We examined the effect of leptin and prolactin on traits associated with lactation. Leptin and prolactin enhanced proliferation (thymidine incorporation) of the mammary gland cells, elevated the cells' proliferation in a dose-responsive manner, and synergized to elevate the expression of amino acid metabolism via a 90% increase in aminopeptidase N expression. Leptin and prolactin decreased apoptosis (decreased caspase-3 expression by 60%) in the same manner. Leptin enhanced the effect of prolactin on all of these processes in bovine mammary explants. Leptin and prolactin regulated mTOR (mammalian target of rapamycin) by increasing expression by 66%, which is one of the signal-transduction junctions involved in the regulation of proliferation, apoptosis, and protein synthesis. These findings support the hypothesis that leptin up-regulates prolactin action in the bovine mammary gland.

Albumin levels predict survival in patients with systolic heart failure

BACKGROUND

Hypoalbuminemia is associated with poor prognosis in patients with certain chronic diseases, such as end-stage renal disease and cancer. Although low serum albumin is common in patients with heart failure (HF), the relationship between albumin and HF prognosis has not been well characterized. This study investigated the effect of serum albumin level on survival in patients with advanced HF.

METHODS

We analyzed 1726 systolic HF patients (age 52 +/- 13 years, ejection fraction [EF] 23% +/- 7%) followed at a university HF center. Albumin level was determined at initial referral. Patients were divided by into groups based on presence of hypoalbuminemia (< or = 3.4 g/dL). Mean albumin was 3.8 +/- 0.6 g/dL, and 25% of patients had hypoalbuminemia.

RESULTS

Patients with and without low albumin levels were similar in age, HF etiology, and EF. Hypoalbuminemia was associated with higher New York Heart Association (NYHA) class, higher serum urea nitrogen, creatinine level, C-reactive protein, and B-type natriuretic peptide but lower levels of sodium, hemoglobin, and cholesterol. In patients with BMI < 25 kg/m(2), 27% had albumin < or = 3.4 g/dL, compared to 22% of those with BMI > or = 25 kg/m(2) (P < .01). One-year survival was 66% in patients with and 83% in those without hypoalbuminemia (P < .0001). Risk-adjusted hazard ratios for 1- and 5-year mortality were 2.2 (1.4-3.3) and 2.2 (1.4-3.2), respectively.

CONCLUSIONS

Hypoalbuminemia is common in HF and is independently associated with increased risk of death in HF. Further investigation of pathophysiologic mechanisms underlying hypoalbuminemia in HF is warranted.

Serum albumin level as a predictor of outcome in traumatic brain injury: potential for treatment

BACKGROUND

Serum albumin level is correlated with outcome in various clinical situations. Albumin has multiple physiologic properties that could be beneficial in brain injury. The Lund therapy for elevated intracranial pressure uses albumin as part of its protocol and demonstrates favorable outcome. We sought to find out if albumin is associated with outcome after traumatic brain injury to justify conducting a randomized trial.

METHODS

A retrospective study of traumatic brain injury patients was conducted. Characteristics known to influence outcome were included in a multiple logistic regression model to analyze predictors of poor outcome at 6 months.

RESULTS

Data were available for 138 patients. The majority of patients (65%) had a severe injury (Glasgow Coma Scale score <9). Seventy percent of patients had a favorable outcome. Albumin levels decrease considerably from normal values in the first few days after injury irrespective of outcome. Albumin remained <25 g/L for a longer period of time in patient with an unfavorable outcome (6 days vs. 3 days, p = 0.012). Multiple logistic regression analysis identified albumin levels, age, Glasgow Coma Scale score at admission, and Injury Severity Score as predictors of poor outcome.

CONCLUSION

Serum albumin level seems to be an independent predictor of poor outcome. The model also identified classic predictors of poor outcome that tends to strengthen its adequacy. Because albumin level is the only modifiable factor influencing outcome, it seems justified to carry out a randomized trial of the use of albumin in the treatment of brain injury.

Increased albumin concentration reduces apoptosis and improves functionality of human islets

Providing sufficient islet mass is important for successful islet transplantation. Apoptosis plays a major role in post-isolation islet cell death, and prevention of apoptosis could improve transplant outcomes. The purpose of this study was to determine whether increased concentration of human albumin (HA) in pre-transplantation culture of human islets would reduce apoptosis. Human islets were cultured in CMRL with 1.5 or 5% of HA for 24 h and apoptosis was evaluated indirectly by measuring caspase 3 activity and tetramethylrhodamine-ethyl-ester (TMRE) in dissociated islets. Islet function and viability were evaluated. Islets cultured in higher albumin concentration presented with lower caspase 3 activity (43.9 +/- 3.9 vs. 67.4 +/- 11.1, p = 0.011), and had increased insulin secretory capacity (Stimulation index 3.76 +/- 0.91 vs 1.23 +/- 0.21, p = 0.023). We conclude that an increase in albumin concentration can prevent apoptosis in isolated human islets. These findings may have implications for islet transplant outcomes.

Albumin reduces blood-brain barrier permeability but does not alter infarct size in a rat model of neonatal stroke

Human serum albumin therapy confers neurobehavioral and histopathologic neuroprotection in adult stroke models. We investigated whether albumin might also be neuroprotective in ischemic brain injury using a transient filament middle cerebral artery occlusion (tfMCAO) model in 10-d-old rat pups treated with 0.25% albumin or saline 1 h after reperfusion. We performed serial neurobehavioral and magnetic resonance imaging (MRI) assessments immediately after tfMCAO (day 0) and on 1, 3, 7, 14, and 28 d. IgG staining to assess blood-brain barrier (BBB) integrity and standard histology was obtained on 1, 3, and 28 d. Hemispheric infarct volumes from MRI were similar in saline and albumin groups (0 h: 39% and 44%; d 1: 46% and 55%; and d 28:10% and 24%) as were neurobehavioral assessments. IgG staining at 3 d post-ischemia showed loss of BBB integrity that was significantly reduced after albumin. Elevated T2 values suggesting vasogenic edema was seen in albumin compared with saline-treated animals, as was increased water mobility (i.e. increased apparent diffusion coefficient (ADC) reflecting cytotoxic edema. The reasons why albumin was not neuroprotective in neonatal stroke compared with adults remain uncertain. Effective strategies in adult models need to be reassessed in the neonate.

Safety and efficacy of albumin administration in trauma

Albumin is one of the oldest known and studied human proteins. It is characterised by diverse physiological and biochemical properties that render it relevant to many aspects of the disordered vascular and cellular functions after trauma. Apart from the ability to maintain the colloid oncotic pressure, human serum albumin has multiple effects, including antioxidant activity and binding affinity for drugs and toxic substances, inhibition of apoptosis and modulation of trauma-induced inflammatory response. According to the current state of knowledge, there are conflicting results regarding the benefits of albumin administration in critically ill patients. Further investigations are warranted to resolve the continued uncertainty about the safety and efficacy of human serum albumin in specific clinical circumstances and selected populations of severely injured patients.

Postmenopausal oral estrogen therapy affects hemostatic factors, but does not account for reduction in the progression of subclinical atherosclerosis

BACKGROUND

Hemostatic factors influenced by postmenopausal hormone therapy may contribute to atherosclerosis. The Estrogen in the Prevention of Atherosclerosis Trial (EPAT), a 2-year, randomized, double-blind, placebo-controlled trial, demonstrated reduced subclinical atherosclerosis progression measured by change in common carotid artery intima-media thickness (CIMT) with unopposed oral 17beta-estradiol.

OBJECTIVES

To assess the effect of postmenopausal hormone therapy on the levels of several hemostatic factors, and the relationship between these factors and the progression of subclinical atherosclerosis.

PATIENTS AND METHODS

We measured tissue plasminogen activator (t-PA) antigen, factor (F) VII, D-dimer and albumin longitudinally, and plasminogen activator inhibitor type 1 (PAI-1) and fibrinogen at trial-end, in 186 postmenopausal women.

RESULTS

Estradiol vs. placebo was associated with greater FVII and lower t-PA, albumin, PAI-1 and fibrinogen (all P < or = 0.001), with no estradiol effect on D-dimer (P = 0.42). Only mean on-trial t-PA was positively associated with the absolute level of CIMT on-trial (r = 0.29, P < 0.0001), but this was attenuated with age and body mass index adjustment. No longitudinally measured hemostatic factor was associated with CIMT progression. However, higher CIMT during the trial was significantly related to increases in t-PA.

CONCLUSIONS

These results confirm previous findings regarding estrogen's effect on hemostatic factors and show that albumin is negatively associated with estrogen therapy. These hemostatic factors did not account for the reduction of CIMT progression with 17beta-estradiol seen in EPAT. Atherosclerosis itself may affect levels of hemostatic factors (reverse causality), with subsequent involvement in atherosclerosis-associated thrombosis.

The Anti-Apoptotic Activity of Albumin for Endothelium Is Mediated by a Partially Cryptic Protein Domain and Reduced by Inhibitors of G-Coupled Protein and PI-3 Kinase, but Is Independent of Radical Scavenging or Bound Lipid

Increased vascular disease occurs with low albumin (human serum albumin, HSA), possibly reflecting specific inhibition of endothelial apoptosis reported for tissue culture. Despite the reported specificity for endothelial protection by HSA, the high but physiological concentrations needed appear more consistent with non-specific low-affinity interactions. We reconcile this contradiction by demonstrating protection is mediated by a partially cryptic HSA protein domain, which becomes more exposed and active following cyanogen bromide fragmentation (p < 0.001). Also, although others reported HSA radical scavenging and bound lipids as important for inhibiting apoptosis in non-endothelial cell types, we demonstrate the protective effect for endothelium is unaffected when HSA radical scavenging is blocked by alkylation, or following delipidation. Further probing the mechanism responsible, we found that the G-coupled protein inhibitors pertussis toxin and suramin reduced protection of endothelium by HSA (p < 0.005), while the tyrosine kinase inhibitor genistein had no effect. Consistent with a role for phosphoinositide 3 kinase (PI3K) was inhibition by both wortmannin and LY294002 (p < 0.05), as well as phosphorylation of Akt, while MAP kinase inhibitors had no effect. We conclude the active site in HSA inhibiting endothelial apoptosis is partially cryptic, and acts via a G-coupled protein PI3K-dependent mechanism.

Albumin therapy in acute stroke patients

Preclinical studies have recently shown that albumin has neuroprotective effects for stroke in animal models. Thus, we sought to evaluate the effects of albumin therapy in patients with acute cerebral infarcts. We prospectively studied 49 patients with moderate-to-severe cerebral infarcts within the middle cerebral arterial territory into one of two groups: the control group (N = 18) received saline, whereas the albumin group (N = 31) received either 40 g or 80 g of albumin within 24 h from symptom onset. The modified National Institutes of Health Stroke Scale (mNIHSS) and diffusion-weighted imaging (DWI) were serially checked. There was no adverse effect related to albumin therapy. Although there was no significant difference in both baseline mNIHSS score and DWI lesion volume on admission, the mNIHSS scores at the 14(th) day after treatment and the increase in DWI lesion volume 72-96 h after treatment were significantly reduced in patients of the albumin group (p = 0.001 and 0.012, respectively); these effects were dose- and time- related. The outcome on the 90(th) day after stroke onset was more favorable in the albumin group than in the control group. Within the albumin group, patients who had patent or recanalized vessels showed more significant improvement than patient without recanalization (p = 0.046). Our results indicate that albumin therapy is a safe and effective modality in patients with acute cerebral infarction. This study also suggests that the effects of albumin therapy may vary depending on vessel status of the patient.

Anesthesia care for adult live donor hepatectomy: our experiences with 100 cases

A total of 100 patients who underwent elective lobar donor hepatectomy from 2000 to 2002 at the University of Rochester Medical Center were reviewed. Assessed clinical data were estimated blood loss, intraoperative central venous pressure (CVP), blood product and fluid administration, perioperative arterial blood gas tension and acid-base state, metabolic status, perioperative serum levels of aspartate aminotransferase, alanine aminotransferase, prothrombin time, albumin, and lactate, procedure duration, and perioperative complications. All patients survived surgery, and the average duration of surgery (from skin incision to skin closure) was 615 +/- 99.6 minutes. Mean blood loss was 549 +/- 391 mL (range, 80-2,500 mL), and only 4 patients required homologous blood transfusion. The intraoperative blood loss did not correlate with CVP values. A total of 72 patients received isotonic sodium bicarbonate solution, and their metabolic variables were superior to those of normal saline group patients (arterial pH, 7.35 +/- 0.03 vs. 7.29 +/- 0.07; base excess, -4.3 +/- 2.4 vs. 7.3 +/- 3.4; and serum bicarbonate level, 20.6 +/- 2.2 vs. 18.6 +/- 2.9). However, the better control of metabolic acidosis was not associated with serum lactate levels or other outcome measures. Maintaining the CVP < 5 mmHg was not associated with blood loss. Clinically significant anesthetic complications were severe metabolic acidosis, pneumothorax and respiratory insufficiency immediately following extubation in the operating room. In conclusion, placement of a thoracic epidural catheter delivering a local anesthetic in addition to intravenous (IV) patient-controlled analgesia with opiates provided safe and effective pain control in most patients. Further prospective studies should shed a light on the optimal care of patients undergoing liver donor hepatic resection.

Assessment of hepatic integrity after ischemic preservation by isolated perfusion in vitro: The role of albumin

Isolated perfusion of rat livers (IPRL) represents an attractive set-up to be used as a an evaluative tool in the easy and reproducible assessment of liver injury, allowing for screening of new approaches to organ preservation without the expenditure of actual transplantation experiments. Depending on the pathology under investigation, controversy exists concerning the inclusion of albumin in the IPRL. The present study evaluates the use of bovine serum albumin (BSA), simultaneously comparing its effect on healthy and ischemically challenged livers in the same model. Rat livers were excised, flushed via portal vein with Histidine-Tryptophan-Ketoglutarate (HTK) solution and preserved for up to 18 h in HTK at 4 degrees C. Perfusion was performed with Krebs-Henseleit buffer with or without addition of 3% BSA. Control preparations were perfused without prior ischemic storage. In the described model, stability of the preparations was documented for up to 120 min of isolated perfusion and addition of 3% BSA had no adverse effects on the viability of nonischemic livers. While liver perfusion without albumin was inappropriate to reveal alterations in parenchymal or vascular integrity after 18 h of cold preservation, albumin in the perfusate significantly and gradually unmasked differences between nonischemic liver preparations and livers stored ischemically for 8 or 18 h. It could be shown that BSA did have a significant modulatory effect on hepatic induction of apoptosis after ischemia in reducing cleavage of caspase 3. The implementation of albumin is advocated since experimental results are pivotally influenced by the presence or absence of this physiologically constitutive compound in the perfusate.

p38 MAPK activation coupled to endocytosis is a determinant of endothelial monolayer integrity

We show in rat lung microvessel endothelial cells (RLMVEC) that endocytosis is a critical determinant of activation of mitogen-activated protein kinase (MAPK) and thereby regulates endothelial monolayer integrity. In RLMVEC grown in serum-free medium, we observed that albumin supplementation induced the phosphorylation of p38 MAPK within 30 min, which persisted for up to 2 h. Engagement of the endocytic machinery regulated the activation of p38 MAPK that contributed to endothelial cell proliferation and reduction of apoptosis. We also observed an interaction between the caveolar protein caveolin-1 and p38 MAPK with reciprocal coimmunoprecipitation assays and colocalization using double-label immunofluorescence staining. Knockdown of caveolin-1 expression with small interfering RNA significantly reduced endocytosis and activation of p38 MAPK and interfered with the ability of endothelial cells to form a confluent monolayer. Thus caveolae-mediated endocytosis and concomitant activation of p38 MAPK may help to maintain endothelial monolayer integrity by signaling proliferation and survival of endothelial cells.

Change of serum albumin and risk of cardiovascular disease and all-cause mortality: Longitudinal Aging Study Amsterdam

The aim of this longitudinal study was to investigate 3-year change in serum albumin concentration as a determinant of incident cardiovascular disease (CVD) and all-cause mortality. Data were from 713 respondents of the Longitudinal Aging Study Amsterdam initially aged 55-85 years. Serum albumin was measured at baseline (1992/1993) and after 3 years. At the 6-year follow-up, incident CVD (among 456 respondents with no prevalent CVD at the 3-year follow-up) and all-cause mortality were ascertained. Overall, 18.9% developed CVD and 10.9% died. After adjustment for potential confounders, a higher level of serum albumin at the 3-year follow-up was associated with a lower risk for incident CVD (relative risk = 0.88, 95% confidence interval (CI): 0.79, 0.98). The risk of incident CVD was 0.88 (95% CI: 0.78, 0.99) per unit (g/liter) increase in change in albumin between 3-year follow-up and baseline. Chronic low serum albumin (<or=43 g/liter at baseline and 3-year follow-up) was not associated with incident CVD (p = 0.22). A clinically relevant decrease in serum albumin (>or=1 standard deviation (2.5 g/liter) between baseline and 3-year follow-up) tended to be associated with a twofold risk (relative risk = 2.00, 95% CI: 0.91, 4.39). For all-cause mortality, no associations were observed. These findings suggest that older persons with a decrease in serum albumin concentration, even within the normal range, might be at increased risk of incident CVD. Change in serum albumin may be used as an early marker for CVD risk.

Albumin administration improves organ function in critically ill hypoalbuminemic patients: A prospective, randomized, controlled, pilot study

OBJECTIVE

To test the hypothesis that administration of albumin to correct hypoalbuminemia might have beneficial effects on organ function in a mixed population of critically ill patients.

DESIGN

: Prospective, controlled, randomized study.

SETTING

Thirty-one-bed, mixed medicosurgical department of intensive care.

PATIENTS

All adult patients with a serum albumin concentration < or =30 g/L were assessed for eligibility. Principal exclusion criteria were expected length of stay <72 hrs, life expectancy <3 months or a do-not-resuscitate order, albumin administration in the preceding 24 hrs, or evidence of fluid overload.

INTERVENTIONS

The 100 patients were randomized to receive 300 mL of 20% albumin solution on the first day, then 200 mL/day provided their serum albumin concentration was <31 g/dL (albumin group), or to receive no albumin (control group).

MEASUREMENTS AND MAIN RESULTS

The primary outcome was the effect of albumin administration on organ function as assessed by a delta Sequential Organ Failure Assessment score from day 1 to day 7 (or the day of intensive care discharge or death, whichever came first). The two groups of 50 patients were comparable at baseline for age, gender, albumin concentration, and Acute Physiology and Chronic Health Evaluation II score. Albumin concentration did not change over time in the control group but increased consistently in the albumin group (p < .001). Organ function improved more in the albumin than in the control group (p = .026), mainly due to a difference in respiratory, cardiovascular, and central nervous system components of the Sequential Organ Failure Assessment score. Diuretic use was identical in both groups, but mean fluid gain was almost three times higher in the control group (1679 +/- 1156 vs. 658 +/- 1101 mL, p = .04). Median daily calorie intake was higher in the albumin than in the control group (1122 [935-1158] vs. 760 [571-1077] kcal, p = .05).

CONCLUSIONS

Albumin administration may improve organ function in hypoalbuminemic critically ill patients. It results in a less positive fluid balance and a better tolerance to enteral feeding.

Interaction of chlorin p6 with bovine serum albumin and photodynamic oxidation of protein

The binding of chlorin p6, a photosensitizer having basic tetrapyrrole structure, to bovine serum albumin (BSA) and oxidation of the protein following photodynamic treatment is studied. The Stern-Volmer plot indicates that binding of chlorin p6 to BSA was of single class. Binding parameters, binding association constant and number of binding sites, were found to be 1.62+/-0.27 x 10(5)M(-1) and 1.086+/-.019, respectively. Photodynamic oxidation of protein was studied by (i) loss of intrinsic fluorescence of protein, (ii) protein carbonyl formation, (iii) protein hydroperoxide (iv) formation of TCA soluble amino groups and (v) SDS-polyacrylamide gel electrophoresis (SDS-PAGE). Intrinsic protein fluorescence was observed to decrease almost linearly as a function of irradiation time at a fixed concentration of chlorin p6 and with increasing concentration of chlorin p6 at fixed time of irradiation. Protein carbonyl and hydroperoxide formation was found to increase with increasing photodynamic treatment. No significant increase in 5% TCA soluble amino groups was observed. SDS-polyacrylamide gel electrophoresis (SDS-PAGE) reveals that photodynamic treatment of BSA in presence of chlorin p6, rose bengal and riboflavin causes non-specific fragmentation of protein. Photodynamic carbonyl formation by chlorin p6 was not inhibited by sodium formate (100 mM) or mannitol (25 mM) but was significantly inhibited by sodium azide (2 mM). Protein carbonyl formation increased almost 90% when H2O was replaced by D2O. The results show that chlorin p6 induced photodynamic oxidation of BSA was mainly mediated by singlet oxygen.

The relationship between albumin, other plasma proteins and variables, and age in the acute phase response after liver resection in man

A large series of plasma albumin (ALB, g/dl) and simultaneous blood and clinical measurements were prospectively performed on 92 liver resection patients, and processed to assess the correlations between ALB, other plasma proteins, additional variables and clinical events. The measurements were performed preoperatively and at postoperative day 1, 3 and 7 in all patients, and subsequently only in those who developed complications or died. In patients who recovered normally ALB was 4.3 +/- 0.4 g/dl (mean +/- SD) preoperatively, 3.7 +/- 0.7 at day 1 and 3, and 3.9 +/- 0.4 at day 7. In patients with complications its decrease was more prolonged. In non-survivors it was 3.4 +/- 0.4 preoperatively, 3.0 +/- 0.4 at day 1, and then decreased further. Regression analysis showed direct correlations between ALB and pseudo-cholinesterase (CHE, U/l, nv 5300-13000), cholesterol (CHOL, mg/dl), iron binding capacity (IBC, mg/dl), prothrombin activity (PA, % of standard reference) and fibrinogen, an inverse correlation with blood urea nitrogen (BUN, mg/dl) for any given creatinine level (CREAT, mg/dl), and weaker direct correlations with hematocrit, other variables and dose of exogenous albumin. An inverse relationship found between ALB and age (AGE, years) became postoperatively (POSTOP) also a function of outcome, showing larger age-related decreases in ALB associated with complications (COMPL: sepsis, liver insufficiency) or death (DEATH). Main overall correlations: CHE = 287.4(2.014)(ALB), r = 0.73; CHOL = 16.5(1.610)(ALB) (1.001)(ALKPH), r = 0.71; IBC = 68.6(1.391)(ALB), r = 0.64; PA = 13.8 + 16.0(ALB), r = 0.51; BUN = 21.3 + 20.2(CREAT) - 6.2(ALB), r = 0.91; ALB = 5.0-0.013(AGE) - {0.5 + 0.003(AGE)( COMPL ) + 0.012(AGE)( DEATH )}( POSTOP ), r = 0.74 [p < 0.001 for each regression and each coefficient; ALKPH = alkaline phosphatase, U/l, nv 98-279, independent determinant of CHOL; discontinuous variables in italics label the change in regression slope or intercept associated with the corresponding condition]. These results suggest that altered albumin synthesis (or altered synthesis unable to compensate for albumin loss, catabolism or redistribution) is an important determinant of hypoalbuminemia after hepatectomy. The correlations with age and postoperative outcome support the concept that hypoalbuminemia is a marker of pathophysiologic frailty associated with increasing age, and amplified by the challenges of postoperative illness.

Lowered levels of serum albumin and HDL-cholesterol in children with a recent mild infection

BACKGROUND

Infections are associated with atherogenic changes in serum.AIM. To elucidate effects of recent infections on risk factors for coronary heart disease in children.

SUBJECTS AND METHODS

In 1983 and again 3 years later, 2458 individuals aged 9, 12, 15, 18 and 21 years were investigated. In 1986, 106 subjects had symptoms of infection during the past 2 weeks before their follow-up visit. Their serum albumin and lipid concentrations were compared to those in 1983 when these individuals probably were healthy. An age- and sex-matched healthy control group from the cohort 1986 was chosen for comparison. For cholesterol age, sex and body mass index specific Z-scores in addition to actual values were used in statistical comparisons.

RESULTS

Serum albumin was 42 g/L in subjects with positive history of infection and 46 g/L in healthy controls (P<0.0001). HDL-cholesterol and the ratio of HDL- to total cholesterol were lower with increasing evidence of infection. Elevated serum C-reactive protein (CRP) or orosomucoid grouped the subjects with high and low serum HDL-cholesterol concentrations better than history of infection alone.

CONCLUSION

A mild infection lowers serum HDL-cholesterol and serum albumin concentrations, which both favour atherogenesis.

Proteomics of human umbilical vein endothelial cells applied to etoposide-induced apoptosis

We have undertaken to continue the proteomic study of human umbilical vein endothelial cells (HUVECs) using the combination of 2-DE, automated trypsin digestion, and PMF analysis after MALDI-TOF MS and peptide sequencing using nano LC-ESI-MS/MS. The overall functional characterization of the 162 identified proteins from primary cultures of HUVECs confirms the metabolic capabilities of endothelium and illustrates various cellular functions more related to cell motility and angiogenesis, protein folding, anti-oxidant defenses, signal transduction, proteasome pathway and resistance to apoptosis. In comparison with controls cells, the differential proteomic analysis of HUVECs treated by the pro-apoptotic topoisomerase inhibitor etoposide further revealed the variation of eight proteins, namely, GRP78, GRP94, valosin-containing protein, proteinase inhibitor 9, cofilin, 37-kDa laminin receptor protein, bovine apolipoprotein, and tropomyosin. These data suggest that etoposide-induced apoptosis of human vascular endothelial cells results from the intricate involvement of multiple apoptosis processes including at least the mitochondrial and the ER stress pathways. The presented 2-D pattern and protein database, as well as the data related to apoptosis of HUVECs, are available at http://www.huvec.com.

Ultrastructural changes in endothelium during apoptosis indicate low microembolic potential

BACKGROUND

Apoptotic endothelium has been suggested to have microthrombotic and microembolic potential. While some describe pro-coagulant activities and platelet binding, others demonstrate maintained fibrinolytic protein and anti-platelet aggregatory activity. Canalicular fragmentation is unique to apoptotic endothelium and is suggested to facilitate size reduction of apoptotic cells to reduce microembolic potential. Despite the potential importance of apoptotic microemboli, there are no reports characterizing changes in cell size and shape during endothelial apoptosis.

METHODS

Here, we describe transmission and scanning electron microscopic studies of apoptotic endothelium and compare changes seen with apoptotic HL-60 cells incapable of canalicular fragmentation.

RESULTS

We demonstrate reduced endothelial size (p<0.05) with progressive apoptosis relative to apoptotic HL-60 cells. Mechanical stress accelerated size reduction of apoptotic endothelium(P< 0.01) but did not affect the size of apoptotic HL-60 cells. Mechanical stress also increased circularity in apoptotic endothelium (p<0.01), suggested to facilitate passage through small vessels. Earlier work indicated that canaliculi form through plasma membrane invagination, but we report fusion of small vesicles contributing to canalicular growth, while canaliculi fuse to form large vacuoles and also dilate at late stages of apoptosis.

CONCLUSIONS

These observations are consistent with the suggestion that endothelium is adapted to minimize microembolic potential and that canalicular fragmentation contributes to this.

Cell-derived microparticles contain caspase 3 in vitro and in vivo

BACKGROUND

Microparticles (MP) from endothelial cells (endothelial microparticles; EMP) circulate in disease states, but the processes such as apoptosis or cell activation underlying their release are unclear.

OBJECTIVES

We investigated whether adherent (viable) or detached (apoptotic) endothelial cells are the possible source of EMP in vitro, i.e. under control and interleukin (IL)-1alpha activation conditions, and in vivo.

METHODS

Adherent and detached endothelial cells, and EMP, were isolated from human umbilical vein endothelial cell cultures (n = 6), treated without or with IL-1alpha (5 ng mL(-1); 24 h). Cell fractions were analyzed by flow cytometry for annexin V binding, propidium iodide (PI) and caspase 3 staining (n = 3). Caspase 3 in EMP was studied using Western blot (n = 6) and flow cytometry (n = 6). Plasma from healthy subjects and systemic lupus erythematosus patients (both n = 3) were analyzed for caspase 3-containing (E)MP.

RESULTS

Detached but not adherent cells double-stained for annexin V and PI, confirming the apoptotic conditions of the detached cells and the viable nature of the adherent cells. Caspase 3 was solely present in the detached cells and procaspase 3 in the adherent cells. Caspase 3 was present in EMP from both control and IL-1alpha-treated cultures. Counts of EMP and detached cells, but not adherent cells, highly correlated (r = 0.959, P < 0.0001). In vivo circulating MP from nucleated (endothelial cells, monocytes) and anucleated cells (platelets, erythrocytes) contained caspase 3.

CONCLUSIONS

EMP contain caspase 3 and may be mainly derived from detached (apoptotic) endothelial cells in vitro. The presence of caspase 3 in MP from anucleated cell types, however, suggests that its presence may not necessarily be related to apoptosis in vivo but may be associated with caspase 3 activation unrelated to apoptosis.

The selective cyclooxygenase-2 inhibitor celecoxib modulates the formation of vasoconstrictor eicosanoids and activates PPARgamma. Influence of albumin

BACKGROUND/AIMS

Selective cyclooxygenase (COX)-2 inhibitors do not adversely affect renal function in experimental cirrhosis. In the current study, we investigated the molecular mechanisms underlying the effects of the selective COX-2 inhibitor, celecoxib, and assessed the influence of albumin on its actions.

METHODS

Rat mesangial cells (RMC) were incubated with celecoxib in the absence or presence of albumin, and levels of selected vasoconstrictor eicosanoids, renin release and alpha-smooth muscle actin (alpha-SMA) expression were determined. The effects of celecoxib on PPARgamma were assessed in RMC co-transfected with PPARgamma and luciferase reporter constructs.

RESULTS

Under resting conditions, RMC expressed COX-1, COX-2 and 12/15-lipoxygenase and mainly generated prostaglandin (PG)E2, thromboxane (TX)B2, 12-hydroxyeicosatetraenoic acid (12-HETE) and 8-epi-PGF2alpha. Celecoxib, in addition to reducing PGE2, significantly decreased 8-epi-PGF2alpha formation. In the presence of albumin, celecoxib also reduced TXB2 and 12-HETE. Albumin per se inhibited PGE2 as well as renin release. In trans-activation assays, celecoxib acted as a PPARgamma agonist whereas albumin inhibited PPARgamma as well as 15d-PGJ2-induced PPARgamma activation. Finally, celecoxib and albumin potentiated the inhibitory effect of 15d-PGJ2 on alpha-SMA expression.

CONCLUSIONS

These data provide novel molecular mechanisms of celecoxib and their modulation by albumin, that may be relevant to prevent renal dysfunction in conditions of unbalanced effective blood volume.

Differential effects of serum constituents on apoptosis induced by the cyclopentenone prostaglandin 15-deoxy-delta12,14-prostaglandin J2 in WISH epithelial cells

Cyclopentenone prostaglandins, delta12-PGJ2 and 15d-PGJ2, have potent anti-tumour and anti-inflammatory activities, and have been shown to induce apoptosis in amnion-derived WISH cells. In this study, we have investigated the protective effects of serum and its constituents (growth factors and albumin) on delta12-PGJ2 and 15d-PGJ2-induced apoptosis in WISH cells. Serum (0.5% w/v) was protective against both delta12-PGJ2 and 15d-PGJ2-induced apoptosis. This was not due to the presence of serum-derived growth factors (EGF, IGF-1 and IGF-2), since they had no significant effect on 15d-PGJ2-induced cell death. In contrast, IGF-1 partially inhibited etoposide-induced apoptosis, confirming the presence of a functional IGF-1 receptor signalling system. Albumin was identified as the key survival factor in serum, since albumin and delipidated albumin exhibited the same level of protection from 15d-PGJ2-induced apoptosis as serum itself. The potential for serum albumin to regulate the bioactivity of cyclopentenone PGs may be of considerable importance in pathological conditions where roles for cyclopentenone PGs have been identified.

Albumin protects against gut-induced lung injury in vitro and in vivo

OBJECTIVE

Since albumin has the ability to detoxify, we assessed whether low-dose albumin could protect against trauma/hemorrhagic shock (T/HS)-induced endothelial cell, lung, gut, and red blood cell (RBC) injury in vivo and endothelial cell injury in vitro.

SUMMARY BACKGROUND DATA

T/HS cause ischemic insult to the gut, resulting in the release of biologically active factors into the mesenteric lymph, which then cause injury to multiple distant organs.

METHODS

In vitro experiments tested the ability of albumin to reduce the cytotoxicity of mesenteric lymph from male rats subjected to T/HS (laparotomy + MAP 30 mm Hg for 90 minutes) for human umbilical vein endothelial cell (HUVEC). In subsequent in vivo experiments, the ability of albumin given as part of the resuscitation regimen to protect against T/HS-induced injury was tested by comparing the magnitude of injury in T/HS rats receiving human albumin (shed blood + 0.12, 0.24, or 0.36 g/kg) or lactated Ringer's solution (shed blood + 2 x volume of shed blood as LR) with that observed in rats subjected to trauma/sham shock. Rats were killed after a 3-hour recovery period and had lung permeability evaluated by bronchoalveolar lavage and myeloperoxidase assays, intestinal microvillous injury by histology, and RBC deformability using ektacytometry.

RESULTS

Both bovine and human albumin prevented T/HS lymph-induced HUVEC cytotoxicity in vitro, even when added 30 minutes after the lymph (viability 15 +/- 4% to 88 +/- 3%, P < 0.01). In vivo RBC deformability was better preserved by blood plus albumin than blood plus lactated Ringer's solution (P < 0.01). Likewise, albumin administration reduced T/HS-induced lung permeability and neutrophil sequestration in a dose-dependent fashion, with 0.36 g/kg of albumin effecting total lung protection (P < 0.01). In contrast, albumin treatment did not prevent T/HS-induced gut injury.

CONCLUSIONS

Low-dose albumin protects against gut lymph-induced lung, HUVEC, and RBC injury by neutralizing T/HS lymph toxicity.

Calmodulin Involvement in Stress-Activated Nuclear Localization of Albumin in JB6 Epithelial Cells

We report that albumin is translocated to the nucleus in response to oxidative stress. Prior measurements have demonstrated that in concert with known transcription factors albumin binds to an antioxidant response element, which controls the expression of glutathione S-transferase and other antioxidant enzymes that function to mediate adaptive cellular responses [Holderman, M. T., Miller, K. P., Dangott, L. J., and Ramos, K. S. (2002) Mol. Pharmacol. 61, 1174-1183]. To investigate the mechanisms underlying this adaptive cell response, we have identified linkages between calcium signaling and the nuclear translocation of albumin in JB6 epithelial cells. Under resting conditions, albumin and the calcium regulatory protein calmodulin (CaM) co-immunoprecipitate using antibodies against either protein, indicating a tight association. Calcium activation of CaM disrupts the association between CaM and albumin, suggesting that transient increases in cytosolic calcium levels function to mobilize intracellular albumin to facilitate its translocation into the nucleus. Likewise, nuclear translocation of albumin is induced by exposure of cells to hydrogen peroxide or a phorbol ester, indicating a functional linkage between reactive oxygen species, calcium, and PKC-signaling pathways. Inclusion of an antioxidant enzyme (i.e., superoxide dismutase) blocks nuclear translocation, suggesting that the oxidation of sensitive proteins functions to coordinate the adaptive cellular response. These results suggest that elevated calcium transients and associated increases in reactive oxygen species contribute to adaptive cellular responses through the mobilization and nuclear translocation of cellular albumin.

Effect of human albumin administration on clinical outcome and hospital cost in patients with subarachnoid hemorrhage

OBJECT

Human albumin is used to induce hypervolemia (central venous pressure [CVP] > 8 mm Hg) after subarachnoid hemorrhage (SAH). Unfortunately, human albumin may increase the mortality rate in critically ill patients; because of this, its use became restricted in the authors' hospital in May 1999. The goal of this study was to determine the effect of human albumin on outcome and cost in patients with SAH before and after this restriction was put into place.

METHODS

All patients with aneurysmal SAH who were admitted to the authors' institution between May 1998 and May 2000 were studied. Basic demographic information, dosage of human albumin given, length of stay, and the incidence of in-hospital deaths and complications were collected. The authors obtained Glasgow Outcome Scale (GOS) scores at 3 months after SAH (good outcome, GOS > or = 4). Data were analyzed using t-test and chi-square analysis. Logistic regression was used to identify independent associations between use of human albumin and outcome. The authors studied 140 patients: 63 who were admitted between May 1998 and May 1999 (Group 1) and 77 treated between June 1999 and May 2000 (Group 2). Two subgroups of patients were further analyzed. Group 1 patients who received human albumin (albumin subgroup, 37 patients) and Group 2 patients who would have received albumin under the old protocol (that is, those who failed to achieve CVP > 8 mm Hg after normal saline administration; nonalbumin subgroup, 47 patients). Patients in the nonalbumin subgroup were more likely to be male (38% compared with 16%), to experience hypertension (55% compared with 30%), to suffer from hypomagnesemia (49% compared with 5.4%), and to have hydrocephalus (47% compared with 27%). There was a trend for these patients to have more vasospasm (28% compared with 19%, p = 0.2). Patients in the albumin subgroup were more likely to have a good outcome at 3 months.

CONCLUSIONS

Administration of human albumin after SAH may improve clinical outcome and reduce hospital cost.

Heterogeneity in the Effect of Albumin and Other Resuscitation Fluids on Intracellular Oxygen Free Radical Production

BACKGROUND

We hypothesized that by studying a suspension of a single cell type in various resuscitation fluids, we could compare their effects on parameters associated with cell death.

METHODS

Jurkat cells were suspended in resuscitation fluids. Using flow cytometry, light scatter, phosphatidylserine translocation, propidium iodide uptake, and intracellular H2O2 production were measured.

RESULTS

Buffer (pH, 7.4) and albumin added to Ringer's lactate inhibited the adverse changes, including intracellular oxygen free radical production. Oxygen free radical production was variable within the cell population and inhibited by albumin but not other colloids or crystalloids. This correlated well with the ability of albumin to enhance metabolic activity. A flavoprotein inhibitor blocked H2O2 production, suggesting that mitochondria are the source of the H2O2 and the variability.

CONCLUSION

Oxygen free radical inhibition by albumin could explain both its beneficial and its harmful effects.

Homocysteine modulates the proteolytic potential of human vascular endothelial cells

Pathological levels of homocysteine induce a metalloproteinase-dependent degradation of the elastic structures in arterial wall. This elastolytic process is preferentially localized toward the internal elastic laminae and in the first layers of the media, suggesting endothelium could participate in extracellular matrix degradation induced by homocysteine. Therefore, we studied the effects of homocysteine on proteolytic potential of endothelial cells. Human umbilical vein endothelial cells were cultured with concentrations of homocysteine matching human physiological (10 microM) and pathological (50, 100, and 250 microM) plasma homocysteine levels. Pathological levels of homocysteine increased the secretion of elastolytic metalloproteinase-2 and -9, but not of metalloproteinase-3 and -7. Homocysteine also increased the expression of human tissue kallikrein, a potential activator of matrix metalloproteinase-2 and -9, while the expression of urokinase plasminogen activator was not altered. These results suggest vascular endothelial cells could participate in the subendothelial degradation of the arterial elastic structures occurring in hyperhomocysteinemia.

Small Volume Albumin Administration Protects Against Hemorrhagic Shock-Induced Bone Marrow Dysfunction

BACKGROUND

Unexpected immunomodulatory effects of colloids and crystalloids prompted an investigation of albumin's ability to prevent bone marrow (BM) suppression following trauma/hemorrhagic shock (T/HS: laparotomy + MAP 30 for 90 mins).

METHODS

In vitro: Normal rat BM was plated for granulocyte-macrophage (CFU-GM) and erythrocyte colony forming units (BFU-E) with 2% v/v plasma from sham (T/SS) or T/HS rats and albumin (2-8 mg/mL). In vivo: Male rats (n = 4/group) were subjected to T/SS or T/HS and resuscitated with shed blood and twice the volume as Lactated Ringer's (LR) or blood and 1, 2, or 3 mL of albumin (50 mg/mL). Bone marrow harvested 3 hours post-resuscitation was plated for CFU-GM and BFU-E.

RESULTS

In vitro: T/HS plasma decreased both CFU-GM and BFU-E growth as compared with T/SS, whereas increasing doses of albumin showed dose-dependent improvement in progenitor growth (p < 0.05). In vivo: The suppression of BM red and white cell progenitor growth seen in T/HS+LR rats as compared with T/SS was fully prevented by as little as 1 mL of albumin (p < 0.05).

CONCLUSIONS

Small doses of albumin fully restore CFU-GM and BFU-E to sham values. We postulate that the binding of circulating toxic factors by albumin may play a role in this prevention of T/HS-induced BM suppression.

Clinical trials for cytoprotection in stroke

To date, many cytoprotective drugs have reached the stage of pivotal phase 3 efficacy trials in acute stroke patients. (Table 1) Unfortunately, throughout the neuroprotective literature, the phrase "failure to demonstrate efficacy" prevails as a common thread among the many neutral or negative trials, despite the largely encouraging results encountered in preclinical studies. The reasons for this discrepancy are multiple, and have been discussed by Dr. Zivin in his review. Many of the recent trials have addressed deficiencies of the previous ones with more rigorous trial design, including more specific patient selection criteria (ensure homogeneity of stroke location and severity), stratified randomization algorithms (time-to-treat), narrowed therapeutic time-window and pharmacokinetic monitoring. Current trials have also incorporated biologic surrogate markers of toxicity and outcome such as drug levels and neuroimaging. Lastly, multi-modal therapies and coupled cytoprotection/reperfusion strategies are being investigated to optimize tissue salvage. This review will focus on individual therapeutic strategies and we will emphasize what we have learned from these trials both in terms of trial design and the biologic effect (or lack thereof) of these agents.

Endothelial cells preparing to die by apoptosis initiate a program of transcriptome and glycome regulation

The protein-based changes that underlie the cell biology of apoptosis have been extensively studied. In contrast, mRNA- and polysaccharide-based changes have received relatively little attention. We have combined transcriptome and glycome analyses to show that apoptotic endothelial cell cultures undergo programmed changes to RNA transcript abundance and cell surface polysaccharide profiles. Although a few of the transcriptome changes were protective, most appeared to prepare cells for apoptosis by decreasing the reception and transduction of pro-survival signals, increasing pro-death signals, increasing abundance of apoptotic machinery, inhibiting cellular proliferation, recruiting phagocytes to regions of cell death, and promoting phagocytosis. Additional transcriptomal changes appeared to alter the synthesis and modification of cell surface glycosaminoglycans. The resultant reduced abundance of sulphated cell surface glycosaminoglycans may further promote cell death by inhibiting the presentation of extracellular matrix-tethered survival factors to their receptors on dying cells. We propose that the transcriptome and glycome regulation presented here synergize with previously described protein-based changes to guide the apoptotic program.

Impaired VE-cadherin/beta-catenin expression mediates endothelial cell degeneration in dilated cardiomyopathy

BACKGROUND

The cross-talk between vascular endothelial growth factor (VEGF)-A, angiopoietin (Ang), and VE-cadherin coregulates endothelial cell (EC) survival. Cardiac expression of VEGF-A but not its receptor KDR is blunted in dilated cardiomyopathy (DCM). Whether VE-cadherin/Ang function is affected in DCM is unknown.

METHODS AND RESULTS

The myocardial expression of VE-cadherin/beta-catenin, Ang-1, Ang-2, and their receptor Tie-2 was examined in DCM, ischemic cardiomyopathy (ICM), and in control subjects through the use of real-time RT-PCR, Western blotting, and immunocytochemistry. EC degeneration was quantified by TEM. RNA interference against VE-cadherin and VEGF deprivation and stimulation were applied to cultured DCM myocardium and human microvascular ECs to examine the interplay between VEGF, VE-cadherin/beta-catenin, and Ang-2. Analysis of tissue sections with similar rates of EC degeneration in both patient groups showed that VE-cadherin/beta-catenin expression was downregulated in DCM only (P<0.05). Although Ang-1 was not changed, Ang-2 expression was downregulated and Tie-2 protein expression was upregulated both in DCM and ICM (P<0.05). The ratio of degenerated to normal ECs was significantly higher in DCM versus ICM (P<0.05). Targeted VE-cadherin gene silencing in cultured human ECs resulted in similar degenerative effects observed in myocardial ECs of DCM patients. In vitro experiments indicated that VE-cadherin/beta-catenin expression is independent of VEGF.

CONCLUSIONS

These results indicate for the first time that the EC survival is impaired in myocardium of patients with DCM involving VE-cadherin/beta-catenin, probably independent of VEGF. Targeting VE-cadherin might be of benefit to counteract the selective EC pathology in DCM.