Colloid Osmotic Pressure Research Articles

Advances in the Physiology of Transvascular Exchange and A New Look At Rational Fluid Prescription.

The Starling principle is a model that explains the transvascular distribution of fluids essentially governed by hydrostatic and oncotic forces, which dynamically allow vascular refilling according to the characteristics of the blood vessel. However, careful analysis of fluid physiology has shown that the principle, while correct, is not complete. The revised Starling principle (Michel-Weinbaum model) provides relevant information on fluid kinetics. Special emphasis has been placed on the endothelial glycocalyx, whose subendothelial area allows a restricted oncotic pressure that limits the reabsorption of fluid from the interstitial space, so that transvascular refilling occurs mainly from the lymphatic vessels. The close correlation between pathological states of the endothelium (eg: sepsis, acute inflammation, or chronic kidney disease) and the prescription of fluids forces the physician to understand the dynamics of fluids in the organism; this will allow rational fluid prescriptions. A theory that integrates the physiology of exchange and transvascular refilling is the "microconstant model", whose variables include dynamic mechanisms that can explain edematous states, management of acute resuscitation, and type of fluids for common clinical conditions. The clinical-physiological integration of the concepts will be the hinges that allow a rational and dynamic prescription of fluids.

PREHOSPITAL PLASMA IS NONINFERIOR TO WHOLE BLOOD FOR RESTORATION OF CEREBRAL OXYGENATION IN A RHESUS MACAQUE MODEL OF TRAUMATIC SHOCK AND HEMORRHAGE.

Introduction: Traumatic shock and hemorrhage (TSH) is a leading cause of preventable death in military and civilian populations. Using a TSH model, we compared plasma with whole blood (WB) as prehospital interventions, evaluating restoration of cerebral tissue oxygen saturation (CrSO 2 ), systemic hemodynamics, colloid osmotic pressure (COP) and arterial lactate, hypothesizing plasma would function in a noninferior capacity to WB, despite dilution of hemoglobin (Hgb). Methods: Ten anesthetized male rhesus macaques underwent TSH before randomization to receive a bolus of O(-) WB or AB(+) plasma at T0. At T60, injury repair and shed blood (SB) to maintain MAP > 65 mm Hg began, simulating hospital arrival. Hematologic data and vital signs were analyzed via t test and two-way repeated measures ANOVA, data presented as mean ± SD, significance = P < 0.05. Results: There were no significant group differences for shock time, SB volume, or hospital SB. At T0, MAP and CrSO 2 significantly declined from baseline, though not between groups, normalizing to baseline by T10. Colloid osmotic pressure declined significantly in each group from baseline at T0 but restored by T30, despite significant differences in Hgb (WB 11.7 ± 1.5 vs. plasma 6.2 ± 0.8 g/dL). Peak lactate at T30 was significantly higher than baseline in both groups (WB 6.6 ± 4.9 vs. plasma 5.7 ± 1.6 mmol/L) declining equivalently by T60. Conclusions: Plasma restored hemodynamic support and CrSO 2 , in a capacity not inferior to WB, despite absence of additional Hgb supplementation. This was substantiated via return of physiologic COP levels, restoring oxygen delivery to microcirculation, demonstrating the complexity of restoring oxygenation from TSH beyond simply increasing oxygen carrying capacity.

The effect of plasma transfusion in an experimental two-hit animal model of transfusion-associated circulatory overload with heart failure.

Transfusion-associated circulatory overload (TACO) is a leading cause of transfusion-related morbidity and mortality. TACO follows a two-hit pathophysiology, where comorbidities like cardiac or renal failure act as the first hit followed by blood transfusion as a second hit. Observational studies suggest that plasma transfusion is more likely to cause TACO than other blood products. We conducted a randomized animal study to gather evidence that plasma transfusion can induce TACO. As a first hit a large myocardial infarction was created in male Wistar rats. Then animals were randomized to receive 4 units of solvent/ detergent-treated pooled plasma (SDP), fresh frozen plasma (FFP), a colloid control (albumin 5%) or a crystalloid fluid control (Ringer's lactate) (n=10 per group). The primary outcome was the difference between pre- and post-transfusion left-ventricular end diastolic pressure (ΔLVEDP). Secondary outcomes were markers for acute lung injury; lung wet/dry weight ratio, PaO2/FiO2 ratio and pulmonary histological assessment. Pre-transfusion characteristics were similar between groups. ΔLVEDP increased significantly after transfusion with SDP (7.7 mmHg; 4.5-10.5) and albumin (13.0 mmHg; 6.5-15.2), but not after FFP (7.9 mmHg, 1.1; 11.3) compared to infusion with Ringer's lactate (0.6 mmHg; 0.4-2.2), p=0.007, p=0.0005 and p=0.14 respectively. There were no significant differences in ΔLVEDP between groups receiving SDP, FFP or albumin. There was no increase in acute lung injury in any group compared to other groups. Circulatory overload, measured as ΔLVEDP, was induced after transfusion of SDP or albumin, but not after infusion of Ringer's lactate. These results show that the effect of plasma transfusion on ΔLVEDP differs from fluid overload induced by crystalloid infusion. Colloid osmotic pressure may be an important component in the development of TACO and should be a target for future research.

Abstract #1405611: A Case Regarding Severe Hypothyroidism Which Complicated to De Novo Nephrotic Syndrome (Minimal Change Disease)

Hypothyroidism is a condition of an under-reactive thyroid. More prevalent in women, 10% exhibit some degree of thyroid insufficiency. It has numerous metabolic effects and may have an impact on renal physiology and worsening kidney function. Hypothyroidism was cited in certain case studies as a contributing factor to minimal change disease, which we will be highlighting here. We report a case of an 82-year-old female with PMH of graves’ disease status post left thyroidectomy in 2009 and was started on Levothyroxine, reported non-compliance, presented to the emergency department with a complaint of generalized edema mostly lower extremities that is progressively worsening over 2 weeks along with foamy urine. Unremarkable physical exam except for 2+ lower extremity pitting edema. On lab, high thyroid stimulating hormone (TSH) was 65.2 ulU/ml, normal Free Thyroxin (FT4) and low Free Triiodothyronine (FT3) 0.4 pg/ml, Serum Creatinine is 4.35 mg/dl, Urinalysis shows >500 protein, urine protein/Cr was 3, hypoalbuminemia and hyperlipidemia were present. A Glomerulopathy workup was initiated. She was admitted for further testing. Autoimmune kidney diseases were ruled out and a renal biopsy was performed, the specimen revealed Minimal change disease. She was started on Prednisone 60 mg daily and Levothyroxine 125 mcg. Three weeks later, patient showed a good response to therapy with an improvement of symptoms and repeated creatinine was 3.8. Hypothyroidism can be caused by partial or total thyroidectomy. As a highly lipophilic substance, Thyroxine binds to receptors that are expressed in cells all over the body to exhibit its physiological action. In patients with thyroidectomy, exogenous levothyroxine is the thyroid hormone supply to the body. Not having enough supply, can alter kidney function by affecting vascular resistance, re-absorptive process, and renal blood flow. It can also affect the RAAS system, beta-adrenergic receptors, and dopaminergic activation of the renal tubular cells. Gradual worsening of kidney function leads to an increase in the loss of free and bound thyroid hormones and eventually increases thyroxine requirement. GFR is reversibly reduced (by about 40%) in more than 55% of adults with hypothyroidism. Thyroxine treatment is effective by reducing edema, capillary permeability of albumin, and plasma colloid osmotic pressure. Proteinuria can sometimes be reversible by prompt initiation of thyroxine treatment. Also, the severity of symptoms plays a role in recovery. More research is needed to determine the relationship between hypothyroidism and nephrotic syndrome as only a few isolated occurrences were reported in the literature.

Expert Consensus on the Use of Human Serum Albumin in Adult Cardiac Surgery.

Expert Consensus on the Use of Human Serum Albumin in Adult Cardiac Surgery.

Hypothesis: Drainage of the peripheral tissue edema by the hyperbaric oxygen therapy because of hyperoxygenation that constricts arterioles and alters the downstream capillary fluid traffic in affected tissues.

Hyperbaric oxygen (HBO) therapy still lacks proper interpretations of its many actions. This hypothesis is based on reports of temporarily elevated peripheral vascular resistance (PVR) during HBO sessions. Besides that, during HBO sessions, hyperoxygenated tissues can reduce their perfusion so much that CO2 can accumulate in them. Tissue perfusion depends on vascular innervation and on the balance between systemic constrictors and local dilators. During an HBO session, increased tissue oxygen levels suppress dilatory mechanisms. Tissue hyperoxygenation increases PVR, suggesting that the HBO action on an edematous tissue may be caused by an oxygen-induced disbalance among Starling capillary forces. The presented hypothesis is that oxygen-caused arteriolar constriction reduces the hydrostatic pressure in downstream capillaries. Thus, more tissue fluid is absorbed in vascular capillaries, under the condition that the plasma colloid osmotic pressure remains unaltered during the HBO session. Among several known mechanisms behind the HBO actions, the vasoconstriction has been listed as a therapeutic modality for the reduction of the tissue edema, for a crush injury, for burns (in an acute phase), and for the compartment syndrome. The Bell's palsy is among often listed indications for the HBO treatment, although evidence is poor and reports of randomized trials are scarce.

The Lymphatic System in Kidney Disease.

The high-capacity vessels of the lymphatic system drain extravasated fluid and macromolecules from nearly every part of the body. However, far from merely a passive conduit for fluid removal, the lymphatic system also plays a critical and active role in immune surveillance and immune response modulation through the presentation of fluid, macromolecules, and trafficking immune cells to surveillance cells in regional draining lymph nodes before their return to the systemic circulation. The potential effect of this system in numerous disease states both within and outside of the kidney is increasingly being explored for their therapeutic potential. In the kidneys, the lymphatics play a critical role in both fluid and macromolecule removal to maintain oncotic and hydrostatic pressure gradients for normal kidney function, as well as in shaping kidney immunity, and potentially in balancing physiological pathways that promote healthy organ maintenance and responses to injury. In many states of kidney disease, including AKI, the demand on the preexisting lymphatic network increases for clearance of injury-related tissue edema and inflammatory infiltrates. Lymphangiogenesis, stimulated by macrophages, injured resident cells, and other drivers in kidney tissue, is highly prevalent in settings of AKI, CKD, and transplantation. Accumulating evidence points toward lymphangiogenesis being possibly harmful in AKI and kidney allograft rejection, which would potentially position lymphatics as another target for novel therapies to improve outcomes. However, the extent to which lymphangiogenesis is protective rather than maladaptive in the kidney in various settings remains poorly understood and thus an area of active research.

Biochemical markers of nephrotic syndrome: An observational, cross-sectional study

BackgroundBlood protein leakage, especially albumin, into the urine is the hallmark of nephrotic syndrome (NS), which poses a serious public health problem. The absence of albumin prompts the liver to produce more proteins to make up the difference. The therapeutic significance of these additional proteins in NS is not yet fully understood. MethodsIn total, 99 patients with NS and 47 persons without NS (control group) were included in this cross-sectional study. Socio-demographic and clinical information were obtained from recruits utilizing a standard questionnaire and a check of the lab order forms for individuals. Each participant had a 6-mL (6 mL) sample of venous blood taken and levels of calcium, C-reactive protein (CRP), albumin, and other proteins in the serum were assayed. The proteins in serum were separated using the electrophoresis technique, and the various fractions were then measured by a densitometer. Calculations were made for the oncotic pressure. ResultsThe NS group had significantly greater levels of serum CRP, urea, alpha-2-globulin, gamma globulins, and M component than the control group (p < 0.05 respectively). Transferrin, total proteins, albumin, beta-1-globulins, calcium, and oncotic pressure were significantly higher in persons without NS compared to the NS group (p < 0.05 respectively). In addition, levels of CRP (odds ratio = 1.41, p = 0.005) and gamma globulin (odds ratio = 4.12, p = 0.005) in the blood were observed to be independent predictors in the occurrence of NS. These two factors increased the likelihood of developing NS by approximately 1.5 and 4 times, respectively. ConclusionAmong the proteins assayed, CRP and gamma globulin were found to be predictors of NS. Nonetheless, further studies are required to understand the mechanisms associated with these serum proteins in NS.

A review of Zenalb 20 with the focus on its application in the clinical setting for patients requiring low sodium or chloride albumin

Abstract Objectives Perceptions that formulations of human albumin solution have not evolved and are interchangeable need to be reconsidered amid renewed appreciation of this therapy in its current uses, and in potential new uses. Initially indicated for volume expansion in severely ill or trauma patients, human albumin solution has been established in a broadening array of clinical applications as understanding of its structure–function relationships has deepened. This article reviews the clinical roles of human albumin solution, the evolution of manufacturing processes and the growing interest in the use of albumin as a therapeutic agent in an expanding range of clinical scenarios. Methods Literature searching was conducted through PubMed, bibliographies of prior publications specific to human albumin solution and ClinicalTrials.gov. This review includes multidisciplinary perspectives on the chemistry, physiology, extraction, processing, formulation and clinical applications of human albumin based on the published literature, authors’ professional experience and product quality-assurance data. Key findings Current formulations of human albumin solution vary in composition, including the use of chemical stabilizers and concentrations of key electrolytes, especially sodium and chloride. Through innovations in manufacturing processes since the 1990s, Zenalb 20 is defined by its high albumin purity, use of a single stabilizer and electrolyte concentrations that are substantially lower than in normal human plasma. The clinical relevance of these features may increase as the use of human serum albumin continues to expand in patient populations receiving multiple medications and fluids, for whom electrolyte balance is crucial. Conclusion As a low electrolyte formulation, Zenalb 20 provides a clinical option to increase oncotic pressure when a colloid is needed without worsening pathological hypernatraemia, hyperchloraemia and hyperkalaemia.

Novel Polymerized Human Serum Albumin For Ex Vivo Lung Perfusion.

Ex vivo lung perfusion (EVLP) is a method of organ preservation to expand the donor pool by allowing organ assessment and repair. Perfusion solution composition is crucial to maintaining and improving organ function during EVLP. EVLP compared perfusates supplemented with either polymeric human serum albumin (PolyHSA) or standard human serum albumin (HSA). Rat heart-lung blocks underwent normothermic EVLP (37°C) for 120 minutes using perfusate with 4% HSA or 4% PolyHSA synthesized at a 50:1 or 60:1 molar ratio of glutaraldehyde to PolyHSA. Oxygen delivery, lung compliance, pulmonary vascular resistance (PVR), wet-to-dry ratio, and lung weight were measured. Perfusion solution type (HSA or PolyHSA) significantly impacted end-organ metrics. Oxygen delivery, lung compliance, and PVR were comparable among groups ( P > 0.05). Wet-to-dry ratio increased in the HSA group compared to the PolyHSA groups (both P < 0.05) suggesting edema formation. Wet-to-dry ratio was most favorable in the 60:1 PolyHSA-treated lungs compared to HSA ( P < 0.05). Compared to using HSA, PolyHSA significantly lessened lung edema. Our data confirm that the physical properties of perfusate plasma substitutes significantly impact oncotic pressure and the development of tissue injury and edema. Our findings demonstrate the importance of perfusion solutions and PolyHSA is an excellent candidate macromolecule to limit pulmonary edema. http://links.lww.com/ASAIO/A980.

Hydroxyethyl Starch-Bovine Hemoglobin Conjugate as an Effective Oxygen Carrier with the Ability to Expand Plasma.

Hemorrhagic shock leads to intravasal volume deficiency, tissue hypoxia, and cellular anaerobic metabolism. Hemoglobin (Hb) could deliver oxygen for hypoxic tissues but is unable to expand plasma. Hydroxyethyl starch (HES) could compensate for the intravasal volume deficiency but cannot deliver oxygen. Thus, bovine Hb (bHb) was conjugated with HES (130 kDa and 200 kDa) to develop an oxygen carrier with the ability to expand plasma. Conjugation with HES increased the hydrodynamic volume, colloidal osmotic pressure, and viscosity of bHb. It slightly perturbed the quaternary structure and heme environment of bHb. The partial oxygen pressures at 50% saturation (P 50) of the two conjugates (bHb-HES130 and bHb-HES200) were 15.1 and 13.9 mmHg, respectively. The two conjugates showed no apparent side effects on the morphology and rigidity, hemolysis, and platelet aggregation of red blood cells of Wistar rats. Thus, bHb-HES130 and bHb-HES200 were expected to function as an effective oxygen carrier with the ability to expand plasma.

КЛИНИЧЕСКИЙ СЛУЧАЙ ЦЕНТРАЛЬНОГО ПОНТИННОГО МИЕЛИНОЛИЗА НА ФОНЕ ПЕРЕНЕСЕННОЙ НОВОЙ КОРОНАРОВИРУСНОЙ ИНФЕКЦИИ

Central pontine myelinolysis is a disease characterized by acute death of myelin sheaths cells in the central part of the pontine pons while maintaining the structural composition of neurons. The word "pontine" indicates the region of the bridge of the brain (pons - pons, region of the brain), and "myelinolysis" refers to the process of destruction of the myelin of the nerve cells of the bridge. The death of brain cells in this pathology is facilitated by an electrolyte imbalance and a sharp change in oncotic pressure. Central pontine myelinolysis often develops in patients suffering from alcoholism, malnutrition, cancer, infections, and other conditions that dramatically disrupt the electrolyte balance of the body. The purpose of this work is to describe a clinical case provoked by a new coronovirus infection COVID-19, which aggravated the course of the disease. The untimely neuroimaging and late seeking medical help also contributed to the poor outcome. As a result of the analysis of this case, a conclusion was made about the need for clinical alertness of pontine myelinolysis and the use of the necessary diagnostic measures, such as neuroimaging methods and the study of metabolic markers. Previously, this rare disease with a poor outcome has not been described in a correlation with coronavirus infection. In connection with the diagnosis established in the early stages and the therapy prescribed in accordance with it, it is possible to limit or prevent the complications of the disease.

Effect of goal-directed fluid therapy based on plasma colloid osmotic pressure on the postoperative pulmonary complications of older patients undergoing major abdominal surgery

BackgroundAs an important component of accelerated rehabilitation surgery, goal-directed fluid therapy (GDT) is one of the optimized fluid therapy strategies and is closely related to perioperative complications and mortality. This article aimed to study the effect of combining plasma colloid osmotic pressure (COP) with stroke volume variation (SVV) as a target for intraoperative GDT for postoperative pulmonary complications in older patients undergoing major abdominal surgery.MethodsIn this study, older patients (n = 100) undergoing radical resection of gastroenteric tumors were randomized to three groups: Group C (n1 = 31) received a conventional infusion regimen, Group S1 (n2 = 34) received GDT based on SVV, and Group S2 (n3 = 35) received GDT based on SVV and COP. The results were recorded, including the lung injury score (LIS); PaO2/FiO2 ratio; lactic acid value at the times of beginning (T0) and 1 h (T1), 2 h (T2), and 3 h (T3) after liquid infusion in the operation room; the total liquid infusion volume; infusion volumes of crystalline and colloidal liquids; urine production rate; pulmonary complications 7 days after surgery; and the severity grading of postoperative pulmonary complications.ResultsThe patients in the S2 group had fewer postoperative pulmonary complications than those in the C group (P < 0.05) and the proportion of pulmonary complications of grade 1 and higher than grade 2 in S2 group was significantly lower than that in C group (P <0.05); the patients in the S2 group had a higher PaO2/FiO2 ratio than those in the C group (P < 0.05), lower LIS than those in the S1 and C groups (P < 0.05), less total liquid infusion than those in the C group (P < 0.05), and more colloidal fluid infusion than those in the S1 and C groups (P < 0.05).ConclusionThe findings of our study show that intraoperative GDT based on COP and SVV can reduce the incidence of pulmonary complications and conducive to shortening the hospital stay in older patients after gastrointestinal surgery.Trial registrationChinese Clinical Trial. no. ChiCTR2100045671. Registry at www.chictr.org.cn on April 20, 2021.

Comparison of Serum Albu-min Levels in The Breast Milk of Breastfeeding Infants Aged 1-3 Months and 4-6 Months

Background: Serum albumin is the most abundant plasma protein in the blood, contributing to maintaining colloid osmotic pressure and binding substances that are poorly soluble in plasma so that they can be distributed throughout the body. Serum albumin levels in breast milk can vary, influenced by various factors such as the lactation phase (age of the baby), number of parities, age and body mass index (BMI) of the mother. This study aims to determine the comparison of serum albumin levels in breast milk of mothers who breastfeed infants aged 1-3 months and 4-6 months and to find the relationship with the number of parities, age and BMI of the mother. Method: Cross-sectional design experimental study, breast milk samples as stored biological fluids were obtained from 58 mothers at the Petamburan and Cilincing Health Centers. Serum albumin levels were measured with the Bromocresol Green (BCG) kit. Results: The results showed that breast milk in the earlier lactation period, namely at 1-3 months, had significantly higher serum albumin levels compared to the serum albumin levels in the 4-6 months age group (p=0.002). Serum albumin levels in breast milk for infants aged 1-3 months did not correlate with mother's parity (p=0.428) and mother's age (p=0.881), but had a significant positive correlation with mother's BMI (p=000). Serum albumin levels in breast milk in the 4-6 months age group did not correlate with mother's parity (p=0.823) and mother's age (p=0.581) but had a strong positive correlation with maternal BMI (p=0.000). Conclusion: Breast milk serum albumin levels are affected by the lactation phase (age of the baby), namely at the age of 1-3 months the baby increases significantly compared to the age of 4-6 months. The level of serum albumin in breast milk is related to the mother's BMI, which increases with increasing mother's BMI.

A series of unfortunate events: Eclampsia with massive post-partum ascites

Postpartum ascites in preeclampsia and eclampsia is a rare complication associated with increased maternal morbidity and mortality. Here, we present a case of postpartum ascites, primarily localized in the gastrointestinal interstitium. Medical management with intravenous albumin to increase oncotic pressure, with piggybacked intravenous diuretics to facilitate fluid removal, showed significant clinical improvement.

PS-BPB05-6: TOLVAPTAN INDUCES BODY FLUID LOSS AND ACTIVATION OF RENAL UREA-DRIVEN WATER CONSERVATION IN NORMAL RATS

Objective: We recently reported that body fluid loss models such as high salt-induced natriuresis, impaired urine concentration ability via kidney injury, and enhanced transepidermal water loss due to skin barrier dysfunction exhibit initial water loss and subsequent activation of the water conservation system in multiple organs. This activation of the water conservation system restores or even increases water content at the tissue level, which may be involved in abnormal body fluid distribution in various disease models. The water conservation system consists of renal urea recycling, the energy-intensive nature of hepato-muscular ureagenesis, and suppression of cardiovascular energy expenditure to save energy for ureagenesis. However, it is not clarified whether pharmacological fluid loss by diuretics activates the water conservation system. In this study, we examined the effects of water diuresis by tolvaptan, a selective vasopressin V2 receptor antagonist, on the water conservation system in normal rats. Design and method: 10-week-old male Sprague Dawley rats were fed with a control diet or a diet containing 0.1% tolvaptan. We measured water intake and urine volume for two weeks and also evaluated time-dependent changes in renal urea recycling and hepato-muscular ureagenesis in these rats. In addition, we also evaluated the effects of tolvaptan on blood pressure, heart rate, and renal sympathetic nerve activity by a radiotelemetry system in separate animals. Results: Tolvaptan markedly increased urine volume up to 126.7 ± 25.9 ml on day-1, which gradually decreased as much as one-third (48.1 ± 18.0 ml) on day-7. Tolvaptan significantly decreased body water content and increased plasma albumin concentration, an indicator of oncotic pressure, on day-1, suggesting that tolvaptan decreased body fluid and plasma volume on day-1. These changes in total body water content and plasma albumin concentration were restored on day-7. The restoration of body fluid on day-7 was associated with an increase in urea transporter A1-associated renal urea recycling. On the other hand, tolvaptan did not alter hepato-muscular ureagenesis or cardiovascular energy expenditure throughout the treatment. Conclusions: Tolvaptan induces initial body fluid loss by water diuresis and subsequent activation of renal urea recycling to restore the water loss. Activation of the water conservation system in addition to a rise in urine volume may be involved in the unknown distinct effect of the diuretics.

Factors Regulating Fluid Restitution and Plasma Volume Reduction over the Course of Hemodialysis.

Over the course of hemodialysis, fluid and protein are restituted from the tissue compartment to the circulation compartment through the endothelia. Our previous model analysis on fluid and protein transport during hemodialysis is expanded to account for changes occurring in the tissue. The measured initial and end plasma protein concentration (PPC, Cp and Cp') for six hemodialysis studies are analyzed by this expanded model. The computation results indicate that the total driving pressure to restitute fluid from the tissue to the circulation ranges from 5.4 to 20.3 mmHg. The analysis identifies that the increase in plasma colloidal osmotic pressure (COP) contributes 78 ± 6% of the total driving pressure, the decrease in microvascular blood pressure 32 ± 4%, the increase in the COP of interstitial fluid -6 ± 3%, and the decrease in interstitial fluid pressure -5 ± 2%. Let this ratio (Cp' - Cp)/Cp' be termed the PPC increment. The six HDs can be divided into three groups which are to have these PPC increments 25.7%, 14.5 ± 2.6(SD)% and 8.3%. It is calculated that their correspondent filtration coefficients are 0.43, 1.29 ± 0.28 and 5.93 mL/min/mmHg and the relative reductions in plasma volume (RRPV) -22.1%, -13.1 ± 6% and -9.4%. The large variations in PPC increments and RRPV show the filtration coefficient is a key factor to regulate the hemodialysis process.

Site-Directed Spin Labeling EPR Spectroscopy for Determination of Albumin Structural Damage and Hypoalbuminemia in Critical COVID-19.

The main factors in the COVID-19 pathology, which can initiate extensive structural changes at the cellular and molecular levels, are the generation of free radicals in abnormal amounts, and oxidative stress. Under "oxidative shock" conditions, the proteins undergo various modifications that affect their function and activity, and as a result distribute malfunctioning protein derivatives in the body. Human serum albumin is a small globular protein characterized by a high overall binding capacity for neutral lipophilic and acidic dosage forms. The albumin concentration is crucial for the maintenance of plasma oncotic pressure, the transport of nutrients, amino acids, and drugs, the effectiveness of drug therapy, and the prevention of drug toxicity. Hypoalbuminemia and structural defects molecule in the protein suggest a risk of changed metabolism and increased plasma concentration of unbound drugs. Therefore, the albumin structural and functional changes accompanied by low protein levels can be a serious prerequisite for ineffective therapy, frequent complications, and high mortality in patients with SARS-CoV-2 infection. The current opinion aims the research community the application of Site-Directed Spin Labeling Electron Paramagnetic Resonance spectroscopy (SDSL-EPR) and 3-Maleimido-PROXYL radical in determining abnormalities of the albumin dynamics and protein concentrations in COVID-19 critical patients.

Rapid Point-of-Care Quantification of Human Serum Albumin in Urine Based on Ratiometric Fluorescence Signaling Driven by Intramolecular H-Bonding.

Human serum albumin exerts multifunctions, such as maintaining the oncotic pressure of plasma, carrying hydrophobic molecules, and acting as the most important antioxidant in the blood. Lower serum albumin levels are linked to several cardiovascular diseases, and dysfunction of albumin reabsorption in the kidney is linked to liver disease, renal disorder, and diabetes. Albumin is thus a powerful diagnostic and prognostic marker; however, its quantification in urine by readily affordable tools is challenging owing to its very low concentration. To address this issue, we developed a ratiometric fluorescent probe with multiple advantages through a systematic structure variation of a benzocoumarin fluorophore and, further, a prototype of a smartphone-based point-of-care device. We determined albumin levels in urine and observed that a smoking person has notably higher urine albumin than a nonsmoking person. The cheap device provides a promising tool for albumin-associated disease diagnosis in communities with limited resources.

Films, Gels and Electrospun Fibers from Serum Albumin Globular Protein for Medical Device Coating, Biomolecule Delivery and Regenerative Engineering.

Albumin is a natural biomaterial that is abundantly available in blood and body fluids. It is clinically used as a plasma expander, thereby increasing the plasma thiol concentration due to its cysteine residues. Albumin is a regulator of intervascular oncotic pressure, serves as an anti-inflammatory modulator, and it has a buffering role due to its histidine imidazole residues. Because of its unique biological and physical properties, albumin has also emerged as a suitable biomaterial for coating implantable devices, for cell and drug delivery, and as a scaffold for tissue engineering and regenerative medicine. As a biomaterial, albumin can be used as surface-modifying film or processed either as cross-linked protein gels or as electrospun fibers. Herein we have discussed how albumin protein can be utilized in regenerative medicine as a hydrogel and as a fibrous mat for a diverse role in successfully delivering drugs, genes, and cells to targeted tissues and organs. The review of prior studies indicated that albumin is a tunable biomaterial from which different types of scaffolds with mechanical properties adjustable for various biomedical applications can be fabricated. Based on the progress made to date, we concluded that albumin-based device coatings, delivery of drugs, genes, and cells are promising strategies in regenerative and personalized medicine.