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Nephrology, Dialysis, Transplantation :... Jun 2023The administration of fluids is one of the most common interventions in the intensive care unit. The effects and side effects of intravenous fluids depend on the amount... (Review)
Review
The administration of fluids is one of the most common interventions in the intensive care unit. The effects and side effects of intravenous fluids depend on the amount administered and their specific composition. Intravenous fluid solutions are either considered crystalloids (for example 0.9% saline, lactated Ringer's solution) or colloids (artificial colloids such as gelatins, and albumin). This narrative review summarizes the physiological principles of fluid therapy and reviews the most important studies on crystalloids, artificial colloids and albumin in the context of critically ill patients.
Topics: Humans; Isotonic Solutions; Crystalloid Solutions; Albumins; Colloids; Intensive Care Units
PubMed: 36170962
DOI: 10.1093/ndt/gfac279 -
European Journal of Internal Medicine Nov 2023Albumin is the most abundant circulating protein and provides about 70% of the plasma oncotic power. The molecule also carries many other biological functions (binding,... (Review)
Review
Albumin is the most abundant circulating protein and provides about 70% of the plasma oncotic power. The molecule also carries many other biological functions (binding, transport and detoxification of endogenous and exogenous compounds, antioxidation, and modulation of inflammatory and immune responses). Hypoalbuminemia is a frequent finding in many diseases, representing usually only a biomarker of poor prognosis rather than a primary pathophysiological event. Despite that, albumin is prescribed in many conditions based on the assumption that correction of hypoalbuminemia would lead to clinical benefits for the patients. Unfortunately, many of these indications are not supported by scientific evidence (or have been even disproved), so that a large part of albumin use is nowadays still inappropriate. Decompensated cirrhosis is the clinical area where albumin administration has been extensively studied and solid recommendations can be made. Besides prevention and treatment of acute complications, long-term albumin administration in patients with ascites has emerged in the last decade has a potential new disease-modifying treatment. In non-hepatological settings, albumin is widely used for fluid resuscitation in sepsis and critical illnesses, with no clear superiority over crystalloids. In many other conditions, scientific evidence supporting albumin prescription is weak or even absent. Thus, given its high cost and limited availability, action is needed to avoid the use of albumin for inappropriate and futile indications to ensure its availability in those conditions for which albumin has been demonstrated to have a real effectiveness and an advantage for the patient.
Topics: Humans; Hypoalbuminemia; Medical Futility; Albumins; Fluid Therapy; Internal Medicine; Liver Cirrhosis
PubMed: 37423819
DOI: 10.1016/j.ejim.2023.07.003 -
Urinary Albumin-to-Creatinine Ratio in Normal Range, Cardiovascular Health, and All-Cause Mortality.JAMA Network Open Dec 2023Although cumulative evidence suggests that elevated urinary albumin-to-creatinine ratio (UACR) in the normal range (<30 mg/g) may be associated with an increased risk of...
IMPORTANCE
Although cumulative evidence suggests that elevated urinary albumin-to-creatinine ratio (UACR) in the normal range (<30 mg/g) may be associated with an increased risk of mortality, few studies have investigated whether cardiovascular health (CVH) modifies the harmful outcomes of high-normal UACR.
OBJECTIVE
To investigate associations of traditionally normal UACR and CVH with all-cause mortality.
DESIGN, SETTING, AND PARTICIPANTS
This cohort study used National Health and Nutrition Examination Survey data from 2005 through 2018 and linked mortality information until 2019. Data were analyzed from March 1 through October 31, 2023. The study included adult participants aged 20 to 79 years with a normal UACR (<30 mg/g) based on Kidney Disease: Improving Global Outcomes criteria.
EXPOSURES
The UACR was treated as a continuous variable and categorized into tertiles delineated as low (<4.67 mg/g), medium (4.67-7.67 mg/g), and high (7.68 to <30 mg/g). Cardiovascular health was assessed using Life's Essential 8 scores and grouped as poor (0-49 points), moderate (50-79 points), and ideal (80-100 points).
MAIN OUTCOMES AND MEASURES
Multivariable Cox proportional hazards regression was used to estimate hazard ratios (HRs) and 95% CIs for associations of UACR with all-cause mortality in total participants and as stratified by CVH groups.
RESULTS
The study included 23 697 participants (mean [SD] age, 45.58 [15.44] years; 11 806 women [49.7%] and 11 891 men [50.3%]). During the median 7.8 years (range, 4.5-11.1 years) of follow-up, 1403 deaths were recorded. Near-linear associations were observed for continuous UACR and CVH with all-cause mortality. Compared with the low UACR group, high UACR in the normal range showed an increased mortality risk in the moderate and poor CVH groups (CVH [50-79]: HR, 1.54 [95% CI, 1.26-1.89]; CVH [0-49]: HR, 1.56 [95% CI, 1.10-2.20]), with a significant multiplicative interaction of UACR and CVH (P < .001).
CONCLUSIONS AND RELEVANCE
The findings suggest that high UACR within the normal range is associated with a significantly increased risk of all-cause mortality, with the association more pronounced in adults with poor CVH status. These findings highlight the importance of risk management for early kidney dysfunction, particularly among individuals with poor CVH.
Topics: Adult; Male; Humans; Female; Middle Aged; Cardiovascular Diseases; Creatinine; Cohort Studies; Nutrition Surveys; Reference Values; Follow-Up Studies; Albumins
PubMed: 38113044
DOI: 10.1001/jamanetworkopen.2023.48333 -
European Journal of Nuclear Medicine... Aug 2023Fibroblast activation protein-α (FAP)-targeting radioligands have recently demonstrated high diagnostic potential. However, their therapeutic value is impaired by the...
Head-to-head comparison of different classes of FAP radioligands designed to increase tumor residence time: monomer, dimer, albumin binders, and small molecules vs peptides.
PURPOSE
Fibroblast activation protein-α (FAP)-targeting radioligands have recently demonstrated high diagnostic potential. However, their therapeutic value is impaired by the short tumor residence time. Several strategies have been tested to overcome this limitation, but a head-to-head comparison has never been done. With the aim to identify strengths and limitations of the suggested strategies, we compared the monomer FAPI-46 versus (a) its dimer (FAPI-46-F1D), (b) two albumin binders conjugates (FAPI-46-Ibu (ibuprofen) and FAPI-46-EB (Evans Blue)), and (c) cyclic peptide FAP-2286.
METHODS
Lu-labeled ligands were evaluated in vitro in cell lines with low (HT-1080.hFAP) and high (HEK-293.hFAP) humanFAP expression. SPECT/CT imaging and biodistribution studies were conducted in HT-1080.hFAP and HEK-293.hFAP xenografts. The areas under the curve (AUC) of the tumor uptake and tumor-to-critical-organs ratios and the absorbed doses were estimated.
RESULTS
Radioligands showed IC in the picomolar range. Striking differences were observed in vivo regarding tumor uptake, residence, specificity, and total body distribution. All [Lu]Lu-FAPI-46-based radioligands showed similar uptake between the two tumor models. [Lu]Lu-FAP-2286 showed higher uptake in HEK-293.hFAP and the least background. The AUC of the tumor uptake and absorbed dose was higher for [Lu]Lu-FAPI-46-F1D and the two albumin binder conjugates, [Lu]Lu-FAPI-46-Ibu and [Lu]Lu-FAPI-46-EB, in HT1080.hFAP xenografts and for [Lu]Lu-FAPI-46-EB and [Lu]Lu-FAP-2286 in HEK293.hFAP xenografts. The tumor-to-critical-organs AUC values and the absorbed doses were in favor of [Lu]Lu-FAP-2286, but tumor-to-kidneys.
CONCLUSION
The study indicated dimerization and cyclic peptide structures as promising strategies for prolonging tumor residence time, sparing healthy tissues. Albumin binding strategy outcome depended on the albumin binding moiety. The peptide showed advantages in terms of tumor-to-background ratios, besides tumor-to-kidneys, but its tumor uptake was FAP expression-dependent.
Topics: Humans; HEK293 Cells; Tissue Distribution; Cell Line, Tumor; Albumins; Peptides; Peptides, Cyclic; Positron Emission Tomography Computed Tomography; Gallium Radioisotopes
PubMed: 37261473
DOI: 10.1007/s00259-023-06272-7 -
Signal Transduction and Targeted Therapy Jun 2023Hepatic mitochondrial dysfunction contributes to the progression of nonalcoholic fatty liver disease (NAFLD). However, the factors that maintain mitochondrial...
Hepatic mitochondrial dysfunction contributes to the progression of nonalcoholic fatty liver disease (NAFLD). However, the factors that maintain mitochondrial homeostasis, especially in hepatocytes, are largely unknown. Hepatocytes synthesize various high-level plasma proteins, among which albumin is most abundant. In this study, we found that pre-folding albumin in the cytoplasm is completely different from folded albumin in the serum. Mechanistically, endogenous pre-folding albumin undergoes phase transition in the cytoplasm to form a shell-like spherical structure, which we call the "albumosome". Albumosomes interact with and trap pre-folding carnitine palmitoyltransferase 2 (CPT2) in the cytoplasm. Albumosomes control the excessive sorting of CPT2 to the mitochondria under high-fat-diet-induced stress conditions; in this way, albumosomes maintain mitochondrial homeostasis from exhaustion. Physiologically, albumosomes accumulate in hepatocytes during murine aging and protect the livers of aged mice from mitochondrial damage and fat deposition. Morphologically, mature albumosomes have a mean diameter of 4μm and are surrounded by heat shock protein Hsp90 and Hsp70 family proteins, forming a larger shell. The Hsp90 inhibitor 17-AAG promotes hepatic albumosomal accumulation in vitro and in vivo, through which suppressing the progression of NAFLD in mice.
Topics: Mice; Animals; Non-alcoholic Fatty Liver Disease; Oxidative Stress; Mitochondria; Albumins; Homeostasis
PubMed: 37321990
DOI: 10.1038/s41392-023-01437-0 -
Frontiers in Immunology 2023Albumins from animals are highly cross-reactive allergens for patients suffering from immunoglobulin E (IgE)-mediated allergy. Approximately 20-30% of cat and dog... (Review)
Review
Albumins from animals are highly cross-reactive allergens for patients suffering from immunoglobulin E (IgE)-mediated allergy. Approximately 20-30% of cat and dog allergic patients show IgE reactivity and mount IgE-mediated allergic reactions to cat and dog albumin. It is astonishing that allergic patients can develop specific IgE responses against animal albumins because these proteins exhibit a more than 70% sequence identity to human serum albumin (HSA) which is the most abundant protein in the blood of the human body. The sequence identity of cat albumin (Fel d 2) and dog albumin (Can f 3) and HSA are 82% and 80%, respectively. Given the high degree of sequence identity between the latter two allergens and HSA one would expect that immunological tolerance would prohibit IgE sensitization to Fel d 2 and Can f 3. Here we discuss two possibilities for how IgE sensitization to Fel d 2 and Can f 3 may develop. One possibility is the failed development of immune tolerance in albumin-allergic patients whereas the other possibility is highly selective immune tolerance to HSA but not to Fel d 2 and Can f 3. If the first assumption is correct it should be possible to detect HSA-specific T cell responses and HSA-containing immune complexes in sensitized patients. In the latter scenario few differences in the sequences of Fel d 2 and Can f 3 as compared to HSA would be responsible for the development of selective T cell and B cell responses towards Fel d 2 as well as Can f 3. However, the immunological mechanisms of albumin sensitization have not yet been investigated in detail although this will be important for the development of allergen-specific prevention and allergen-specific immunotherapy (AIT) strategies for allergy to albumin.
Topics: Humans; Cats; Animals; Dogs; Albumins; Hypersensitivity; Allergens; Immunoglobulin E; Serum Albumin, Human
PubMed: 37928538
DOI: 10.3389/fimmu.2023.1241518 -
Clinical Gastroenterology and... Sep 2023Hepatorenal syndrome (HRS) can occur in patients with cirrhosis and ascites due to splanchnic vasodilation, renal hypoperfusion, and vasoconstriction. HRS is a diagnosis... (Review)
Review
BACKGROUND & AIMS
Hepatorenal syndrome (HRS) can occur in patients with cirrhosis and ascites due to splanchnic vasodilation, renal hypoperfusion, and vasoconstriction. HRS is a diagnosis of exclusion and portends a poor prognosis, with upward of 80% mortality at 2 weeks without treatment. This review will highlight randomized controlled trials for HRS pharmacotherapy.
METHODS
A PubMed review of randomized controlled trials conducted over the past 25 years was undertaken; 18 studies were included.
RESULTS
Initial studies showed that norepinephrine is as effective as terlipressin for HRS reversal. Midodrine with octreotide and albumin is less effective than terlipressin but better than albumin alone at improving 30-day mortality. Recently, terlipressin with albumin led to significantly higher rates of HRS reversal compared to albumin alone. Non-response to terlipressin can predict 90-day mortality in acute-on-chronic-liver failure.
CONCLUSIONS
Our current understanding of HRS treatment is improved by recent randomized clinical trials. Previous studies using varying medication doses along with the "old" definition of hepatorenal syndrome (HRS type 1) rather than HRS-AKI means that there is still a need for future multicenter prospective studies further refining the risk-benefit ratio of vasoconstrictors for HRS-AKI patients. The Food and Drug Administration has approved terlipressin for use in September 2022. Because it will take time to adapt into clinical practice, less cost-prohibitive vasoconstrictors should still be considered. Opportunities also exist to clarify the safety, timing of initiation, as well as possible discontinuation of terlipressin.
Topics: United States; Humans; Hepatorenal Syndrome; Terlipressin; Prospective Studies; Acute Kidney Injury; Vasoconstrictor Agents; Albumins; Multicenter Studies as Topic
PubMed: 37625864
DOI: 10.1016/j.cgh.2023.06.006 -
Clinical and Experimental Medicine Mar 2024Cirrhosis is an advanced-stage liver disease that occurs due to persistent physiological insults such as excessive alcohol consumption, infections, or toxicity. It is... (Review)
Review
Cirrhosis is an advanced-stage liver disease that occurs due to persistent physiological insults such as excessive alcohol consumption, infections, or toxicity. It is characterised by scar tissue formation, portal hypertension, and ascites (accumulation of fluid in the abdominal cavity) in decompensated cirrhosis. This review evaluates how albumin infusion ameliorates cirrhosis-associated complications. Since albumin is an oncotic plasma protein, albumin infusion allows movement of water into the intravascular space, aids with fluid resuscitation, and thereby contributes to resolving cirrhosis-induced hypovolemia (loss of extracellular fluid) seen in ascites. Thus, albumin infusion helps prevent paracentesis-induced circulatory dysfunction, a complication that occurs when treating ascites. When cirrhosis advances, other complications such as spontaneous bacterial peritonitis and hepatorenal syndrome can manifest. Infused albumin helps mitigate these by exhibiting plasma expansion, antioxidant, and anti-inflammatory functions. In hepatic encephalopathy, albumin infusion is thought to improve cognitive function by reducing ammonia concentration in blood and thereby tackle cirrhosis-induced hepatocyte malfunction in ammonia clearance. Infused albumin can also exhibit protective effects by binding to the cirrhosis-induced proinflammatory cytokines TNFα and IL6. While albumin administration has shown to prolong overall survival of cirrhotic patients with ascites in the ANSWER trial, the ATTIRE and MACHT trials have shown either no effect or limitations such as development of pulmonary oedema and multiorgan failure. Thus, albumin infusion is not a generic treatment option for all cirrhosis patients. Interestingly, cirrhosis-induced structural alterations in native albumin (which lead to formation of different albumin isoforms) can be used as prognostic biomarkers because specific albumin isoforms indicate certain complications of decompensated cirrhosis.
Topics: Humans; Ascites; Ammonia; Liver Cirrhosis; Albumins; Protein Isoforms
PubMed: 38551716
DOI: 10.1007/s10238-024-01315-1 -
Circulation Research Sep 2023Cardiac conduction is understood to occur through gap junctions. Recent evidence supports ephaptic coupling as another mechanism of electrical communication in the...
BACKGROUND
Cardiac conduction is understood to occur through gap junctions. Recent evidence supports ephaptic coupling as another mechanism of electrical communication in the heart. Conduction via gap junctions predicts a direct relationship between conduction velocity (CV) and bulk extracellular resistance. By contrast, ephaptic theory is premised on the existence of a biphasic relationship between CV and the volume of specialized extracellular clefts within intercalated discs such as the perinexus. Our objective was to determine the relationship between ventricular CV and structural changes to micro- and nanoscale extracellular spaces.
METHODS
Conduction and Cx43 (connexin43) protein expression were quantified from optically mapped guinea pig whole-heart preparations perfused with the osmotic agents albumin, mannitol, dextran 70 kDa, or dextran 2 MDa. Peak sodium current was quantified in isolated guinea pig ventricular myocytes. Extracellular resistance was quantified by impedance spectroscopy. Intercellular communication was assessed in a heterologous expression system with fluorescence recovery after photobleaching. Perinexal width was quantified from transmission electron micrographs.
RESULTS
CV primarily in the transverse direction of propagation was significantly reduced by mannitol and increased by albumin and both dextrans. The combination of albumin and dextran 70 kDa decreased CV relative to albumin alone. Extracellular resistance was reduced by mannitol, unchanged by albumin, and increased by both dextrans. Cx43 expression and conductance and peak sodium currents were not significantly altered by the osmotic agents. In response to osmotic agents, perinexal width, in order of narrowest to widest, was albumin with dextran 70 kDa; albumin or dextran 2 MDa; dextran 70 kDa or no osmotic agent, and mannitol. When compared in the same order, CV was biphasically related to perinexal width.
CONCLUSIONS
Cardiac conduction does not correlate with extracellular resistance but is biphasically related to perinexal separation, providing evidence that the relationship between CV and extracellular volume is determined by ephaptic mechanisms under conditions of normal gap junctional coupling.
Topics: Animals; Guinea Pigs; Dextrans; Connexin 43; Myocytes, Cardiac; Sodium; Gap Junctions; Albumins; Mannitol; Action Potentials
PubMed: 37681314
DOI: 10.1161/CIRCRESAHA.123.322567 -
Frontiers in Immunology 2023Acute respiratory distress syndrome (ARDS) is a common complication of influenza virus (IV) infection. During ARDS, alveolar protein concentrations often reach 40-90% of...
INTRODUCTION
Acute respiratory distress syndrome (ARDS) is a common complication of influenza virus (IV) infection. During ARDS, alveolar protein concentrations often reach 40-90% of plasma levels, causing severe impairment of gas exchange and promoting deleterious alveolar remodeling. Protein clearance from the alveolar space is at least in part facilitated by the multi-ligand receptor megalin through clathrin-mediated endocytosis.
METHODS
To investigate whether IV infection impairs alveolar protein clearance, we examined albumin uptake and megalin expression in MLE-12 cells and alveolar epithelial cells (AEC) from murine precision-cut lung slices (PCLS) and in vivo, under IV infection conditions by flow cytometry and western blot. Transcriptional levels from AEC and broncho-alveolar lavage (BAL) cells were analyzed in an in-vivo mouse model by RNAseq.
RESULTS
IV significantly downregulated albumin uptake, independently of activation of the TGF-β1/GSK3β axis that has been previously implicated in the regulation of megalin function. Decreased plasma membrane abundance, total protein levels, and mRNA expression of megalin were associated with this phenotype. In IV-infected mice, we identified a significant upregulation of matrix metalloproteinase (MMP)-14 in BAL fluid cells. Furthermore, the inhibition of this protease partially recovered total megalin levels and albumin uptake.
DISCUSSION
Our results suggest that the previously described MMP-driven shedding mechanisms are potentially involved in downregulation of megalin cell surface abundance and clearance of excess alveolar protein. As lower alveolar edema protein concentrations are associated with better outcomes in respiratory failure, our findings highlight the therapeutic potential of a timely MMP inhibition in the treatment of IV-induced ARDS.
Topics: Animals; Mice; Alveolar Epithelial Cells; Low Density Lipoprotein Receptor-Related Protein-2; Biological Transport; Albumins; Orthomyxoviridae Infections; Orthomyxoviridae
PubMed: 37727782
DOI: 10.3389/fimmu.2023.1260973