Albumin, an interesting and functionally diverse protein, varies from 'native' to 'effective' (Review)

The effects of free fatty acid-free bovine serum albumin and palmitate on pancreatic β-cell function

Pancreatic β-cells release insulin in response to fluctuations in plasma glucose, amino acids, and free fatty acids (FFA). Clonal cell lines and isolated islets serve as essential early models for studying the impact of nutrients and evaluating potential therapies to address β-cell dysfunction. Acute and chronic changes in FFA levels have been shown to have positive and negative effects on β-cell function both in vivo and in vitro. A key problem in comparing islet lipid studies from different laboratories is that a wide variety of methods are used to isolate, culture, and assess islet function. The current study compares bovine serum albumin (BSA) types and lipid preparation methods in clonal 832/13 cells and human islets. Changing the percentage and culture conditions when using FFA-free BSA can negatively affect β-cell function compared to regular BSA. Preparing palmitate with FFA-free BSA can rescue insulin secretion compared to treating cells alone with FFA-free BSA. Different methods of preparing palmitate can have unique effects on insulin secretion. Overall, interpreting the effects of lipids on β-cell function is complicated by a number of variables that need to be controlled for in islet experiments.

Impact of Early Administration of Albumin on Mortality Among Severe COVID-19 Patients, China

Purpose

Hypoalbuminemia is commonly observed in patients with severe Coronavirus Disease 2019 (COVID-19) and is independently associated with adverse outcomes. However, the efficacy of albumin administration on the clinical prognosis of these patients remains uncertain.

Patients and Methods

This multicenter retrospective study enrolled 458 patients with severe COVID-19 in four medical centers from December 1, 2022, to June 1, 2024. Clinical features and laboratory variables were collected through electronic medical records. The cohorts were divided into two groups: albumin administration and non-albumin administration. Propensity score matching (PSM) was used for minimizing confounding effect. Statistical analyses were conducted to assess the relationship between early albumin administration and 28-day mortality.

Results

Four hundred and fifty-eight severe COVID-19 cases were included in the study, of which 167 (36.5%) received early albumin administration, while 291 (63.5%) did not. Among these patients, 140 experienced in-hospital mortality and 318 survived. Compared to survivors, non-survivors exhibited significantly lower serum albumin levels (29.1g/L vs.33.8g/L, p < 0.05). In comparison to patients with admission albumin levels ≥30 g/L, those with albumin levels <30 g/L had a significantly higher in-hospital mortality (48.4% vs 21.1%, p < 0.001). Prior to PSM, the albumin administration group demonstrated significantly higher 28-day and in-hospital cumulative survival rates compared to the non-albumin group (both p < 0.001). However, no significant differences were observed between the two groups following PSM (p = 0.21 and p = 0.41, respectively).

Conclusion

Hypoalbuminemia was correlated with adverse outcomes in severe COVID-19 patients. However, early albumin administration did not reduce 28-day mortality and in-hospital mortality in these patients, and more relative RCTs were required for validation.

Assessing the environmental risks of sulfonylurea pollutants: Insights into the risk priority and structure-toxicity relationships

Sulfonylureas are widely used herbicides globally; however, the health risks associated with exposure to these compounds are poorly understood. This study used fuzzy clustering to categorize 44 sulfonylurea compounds into three risk priority levels (I, II, and III) and further investigated their structure-toxicity relationships. The order of the risk priority levels was level I＜level II＜level III. The pecking order of protein affinity was on the order of 104 M-1, which was consistent with the order of the risk priority levels. Moreover, toxic conjugations induced significant changes in protein conformation, with high-risk sulfonylurea causing substantial conformational changes. Given that the conformations of sulfonylurea within the reactive domain were highly similar, the patterns of toxic actions were considerably similar as well. Structure-toxicity relationship analysis indicated a positive correlation among Gibbs free energy change (ΔG°), affinity between sulfonylurea and protein, logarithm of the octanol-water partition coefficient (logKow), and risk priority. Specifically, a higher ΔG° value corresponded to stronger affinity, and a higher logKow value corresponded to a higher environment risk. The electronegativity of the aromatic ring on the left side of the sulfonylurea molecule is a key determinant influencing affinity - higher electronegativity of this aromatic ring weakened the affinity of sulfonylurea for protein and reduced the risk. When the aromatic ring on the left side of sulfonylurea was consistent, an increase in the electronegativity of the heterocyclic ring on the right side resulted in a stronger affinity for protein and an increased risk. This study provides a mechanistic foundation for evaluating the health risks associated with exposure to sulfonylurea.

Association of malnutrition risk evaluated by the geriatric nutritional risk index with post-stroke myocardial injury among older patients with first‑ever ischemic stroke

BACKGROUND

Post-stroke myocardial injury is a potentially preventable complication after acute ischemic stroke. Therefore, identifying modifiable variables, such as nutritional status, is crucial for reducing the risk of post-stroke myocardial injury. This study aimed to investigate the association between malnutrition risk on admission, as evaluated by the Geriatric Nutritional Risk Index (GNRI), and post-stroke myocardial injury in elderly patients with first‑ever ischemic stroke.

METHODS

We conducted this study using the GNRI score to evaluate the nutritional status of older patients with first‑ever ischemic stroke. The primary outcome of interest was post-stroke myocardial injury. Restricted cubic spline (RCS) was executed to assess the dose-effect relationship between the GNRI score and post-stroke myocardial injury. The correlation of malnutrition risk identified by GNRI score for post-stroke myocardial injury was examined using multivariate logistic regression analysis. To balance the potential confounders and verify the robustness of the results, propensity score matching (PSM) was further conducted.

RESULTS

Based on the GNRI score, 30.8% of patients were at moderate to severe risk of malnutrition. The overall incidence of post-stroke myocardial injury was 33.2%. The adjusted RCS analysis revealed a negative dose-response relationship between the GNRI score and post-stroke myocardial injury (P for non-linearity = 0.536). After adjusting for confounders, moderate to severe malnutrition risk, as evaluated by the GNRI score, was substantially associated with an increased risk of post-stroke myocardial injury (OR: 3.25; 95% CI: 1.93-5.48; P < 0.001). Following PSM adjustment, the association between the GNRI score and post-stroke myocardial injury remained significantly robust (OR: 4.28; 95% CI: 2.34-7.83; P < 0.001).

CONCLUSION

Malnutrition risk on admission is associated with higher risk of post-stroke myocardial injury among elderly patients with first‑ever ischemic stroke. Early screening for malnutrition risk is crucial in the management of patients with first‑ever ischemic stroke.

Sulfonated albumin from hepatocytes accelerates liver fibrosis in nonalcoholic fatty liver disease through endoplasmic reticulum stress

BACKGROUND

Posttranslational modifications (PTM) of albumin occur in liver diseases; however, little is known about the source and function of sulfonated albumin, a significant modification of albumin occurring in nonalcoholic fatty liver disease (NAFLD). We aimed to investigate the mechanism underlying sulfonated albumin production and its role in the progression of NAFLD-related liver fibrosis.

METHODS

Serum samples from healthy controls and patients with NAFLD were used to measure the proportion of sulfonated albumin. Mice models with NAFLD fed with high-fat diet (HFD) and methionine choline-deficient diet (MCD) were constructed. RNA sequencing, KEGG analysis, and GSEA were used to explore the mechanism of sulfonated albumin production and its mechanism of activating hepatic stellate cells (HSCs) and promoting the progression of liver fibrosis in NAFLD.

RESULTS

Sulfonated albumin levels increased significantly in both human and mouse NAFLD serum samples. In vivo studies in mice have shown that the intraperitoneal injection of sulfonated albumin promotes inflammation, hepatic steatosis, and liver fibrosis in NAFLD. In addition, autophagy has been verified as a key mechanism in the regulation of sulfonated albumin production. We also demonstrated that reactive oxygen species (ROS) production depends on the accumulation of damaged mitochondria and affects the production of sulfonated albumin under the regulation of autophagy. Hepatocyte-derived sulfonated albumin activates HSCs through the GAL3 receptor, thereby activating the endoplasmic reticulum (ER) stress pathway and promoting profibrotic activation of HSCs.

CONCLUSIONS

Our study demonstrated that sulfonated albumin activated HSCs through GAL3, thereby accelerating NAFLD-related liver fibrosis. Serum sulfonated albumin may be a potential diagnostic marker for liver fibrosis and an important target for the treatment of NAFLD-related liver fibrosis.

Integrated metabolomics and network pharmacology analysis to reveal the protective effect of Complanatoside A on nonalcoholic fatty liver disease

INTRODUCTION

The rising prevalence and severe consequences of nonalcoholic fatty liver disease (NAFLD) have driven the quest for preventive medications. Complanatoside A (CA) is the marked flavonoid of Astragali complanati semen, a traditional Chinese herb that acts on the liver meridian and is widely used to treat liver problems. CA has been proven to have considerable lipid-lowering and liver-protective effects in vitro. However, the efficacy of CA in preventing NAFLD has yet to be shown in vivo.

METHODS

First, the effectiveness of CA against NAFLD was assessed using a high-fat diet (HFD) mouse model. Second, the CA protective mechanism against NAFLD was investigated using a combined metabolomics and network pharmacology strategy. Differential metabolites were identified by metabolomics-based analyses, and metabolic pathway analysis was accomplished by MetaboAnalyst. Potential therapeutic targets were obtained through network pharmacology. Finally, key targets were identified via compound-target networks and validated by molecular docking and western blotting.

RESULTS

CA prevented NAFLD mainly by reducing liver lipid accumulation in HFD mice. Metabolomics identified 22 potential biomarkers for CA treatment of NAFLD, primarily involving glycerophospholipid and arachidonic acid metabolism. Fifty-one potential targets were determined by network pharmacology. Co-analysis revealed that albumin, peroxisome proliferator-activated receptor-alpha, retinoid X receptor alpha, interleukin-6, and tumor necrosis factor alpha were key targets.

CONCLUSION

This experiment revealed that CA has a preventive effect on NAFLD, primarily by regulating the peroxisome proliferator-activated receptor-alpha/retinoid X receptor alpha pathway. Furthermore, it provides evidence supporting the potential use of CA in the long-term prevention of NAFLD.

The Biological Effect of Enriching the Plasma Content in Platelet-Rich Plasma: An In Vitro Study

BACKGROUND

Platelet-rich plasma (PRP) formulations have become valuable therapeutic tools in regenerative medicine. In addition, these blood derivates have been successfully included in cell therapy as fetal bovine serum substitutes, due to the real need to avoid the risk of host immunologic reactions and the animal disease transmission associated with reagents from animal origin. However, the protocols for obtaining them should be optimized to improve their biological potential.

METHODS

PRP-derived preparations with different concentrations of the platelet and plasma components were obtained from the blood of five donors by freeze-drying. Measurements of the pH, protein, and growth factor concentration were performed. Moreover, their biological effects on cell proliferation and migration and their angiogenic potential were assessed.

RESULTS

An increased plasma component concentration resulted in an augmented quantity of the total protein content, a significative variation in the hepatocyte growth factor concentration, and an experimental but clinically irrelevant alteration of the pH value. No significant changes were induced in their potential to enhance proliferative and migratory responses in epithelial cells, with the latter being reduced for dermal fibroblasts. The endothelial cell capacity for tube formation was significatively reduced.

CONCLUSIONS

An increased blood plasma content did not improve the biological potential of the formulations. However, they have emerged as a promising approach for regenerative therapies where neovascularization must be avoided.

Analytical Insights into Methods for Measuring Ischemia-Modified Albumin

Ischemia-modified albumin (IMA) has emerged as a pivotal biomarker for the early detection of ischemic conditions, particularly myocardial ischemia, where timely diagnosis is crucial for effective intervention. This review provides an overview of the analytical methods for assessment of IMA, including Albumin Cobalt Binding (ACB), Albumin Copper Binding (ACuB), Enzyme-Linked Immunosorbent Assay (ELISA), new techniques such as liquid crystal biosensors (LCB), quantum dot coupled X-ray fluorescence spectroscopy (Q-XRF), mass spectrometry (MS), and electron paramagnetic resonance (EPR) spectroscopy. Each method was thoroughly examined for its analytical performance in terms of sensitivity, specificity, and feasibility. The ACB assay is the most readily implementable method in clinical laboratories for its cost-effectiveness and operational simplicity. On the other hand, the ACuB assay exhibits enhanced sensitivity and specificity, driven by the superior binding affinity of copper to IMA. Furthermore, nanoparticle-enhanced immunoassays and liquid crystal biosensors, while more resource-intensive, significantly improve the analytical sensitivity and specificity of IMA detection, enabling earlier and more accurate identification of ischemic events. Additionally, different biological matrices, such as serum, saliva, and urine, were reviewed to identify the most suitable for accurate measurements in clinical application. Although serum was considered the gold standard, non-invasive matrices such as saliva and urine are becoming increasingly feasible due to advances in technology. This review underscores the role of IMA in clinical diagnostics and suggests how advanced analytical techniques have the potential to significantly enhance patient outcomes in ischemic disease management.

Albumin in Normovolemic Fluid Management for Severe Traumatic Brain Injury: Controversies and Research Gaps

Traumatic brain injury (TBI) is a significant public health issue characterized by high mortality rates and long-term complications. This commentary examines the controversial role of the use of albumin in the fluid management of patients with severe TBI. Despite its physiological benefits, the clinical use of albumin remains controversial due to the fact that various studies have yielded mixed results. Serum albumin is important for maintaining normovolemia, primarily through its contribution to colloid osmotic pressure, which helps to retain fluid in the circulatory system. This review highlights the existing evidence, examines inconsistencies in guideline recommendations, and suggests future research directions to clarify the efficacy and safety of the use of albumin in maintaining normovolemia in patients with TBI. The review also discusses the potential benefits of small-volume resuscitation strategies for the management of acute kidney injury in TBI patients, drawing parallels with the management of septic acute kidney injury. The need for further well-designed randomized controlled trials and ethical considerations in studies regarding the use of hyperoncotic albumin in TBI management is emphasized.

Association between C-reactive protein to albumin ratio and subclinical myocardial injury in the general population free from cardiovascular disease

OBJECTIVE

The study aimed to examine the role of the C-reactive protein to albumin ratio (CAR) as an inflammatory biomarker in relation to subclinical myocardial injury (SC-MI), addressing the limited knowledge of their association.

METHODS

The study included 5,949 individuals without cardiovascular disease (CVD) from the National Health and Nutrition Examination Survey. SC-MI was identified through a Cardiac Infarction Injury Score (CIIS) of ≥ 10 units based on a 12-lead electrocardiogram. The study used multivariate logistic regression models, adjusted for potential confounders, to evaluate the relationship between CAR and SC-MI. Subgroup analyses were conducted to substantiate the results, and the non-linear correlation was assessed via restricted cubic spline (RCS) regression.

RESULTS

The RCS curve showed a significant positive correlation between CAR and SC-MI (P for nonlinear = 0.2496). When adjusted for all confounders, individuals in the highest tertile of CAR exhibited a higher likelihood of SC-MI compared to those in the lowest tertile, with an odds ratio (OR) of 1.21 (95% CI: 1.06-1.39, P for trend = 0.029). A 10-unit increment in CAR was linked to a 3.6% heightened risk of SC-MI [OR = 1.036 (95% CI: 1.006, 1.066)], with this association being more prominent among male adults, non-smokers, married individuals, those without diabetes mellitus, and those with no history of cancer.

CONCLUSION

The findings of this study suggest a positive correlation between CAR and SC-MI among the US adult population, indicating the potential of CAR in enhancing SC-MI prevention strategies in the general population.

The Relationship Between Hyperalbuminemia and Unscheduled Medical Visits: A Retrospective Cohort Study

Introduction Hyperalbuminemia, defined as elevated serum albumin levels, may influence healthcare utilization, particularly unscheduled medical visits. The sympathetic nervous system (SNS) regulates serum albumin, which is crucial for maintaining oncotic pressure and substance transport. SNS instability, linked to chronic diseases, can impact albumin levels. This study investigates the association between hyperalbuminemia and unscheduled medical visits in community hospital outpatient departments, aiming to establish its potential as a predictor of healthcare utilization. Methods This retrospective cohort study utilized electronic medical records from Unnan City Hospital, Japan, from September 2021 to August 2023. Participants were over 15 years old and had albumin data available, excluding those with acute albumin conditions. The case group consisted of 321 hyperalbuminemia patients (serum albumin ≥ 5 g/dL), matched monthly with 16 controls. Data on demographics, chronic diseases, and unscheduled medical visits were collected. Multivariate logistic regression analyzed the association between hyperalbuminemia and unscheduled medical visits. Results Among 716 participants, the hyperalbuminemia group (mean age 59.13 years) was younger than the non-hyperalbuminemia group (mean age 74.36 years). Hyperalbuminemia patients had a higher BMI, pulse rate, and prevalence of diabetes, dyslipidemia, and brain stroke. Significant associations were found between hyperalbuminemia and unscheduled medical visits (OR 2.35, 95% CI 1.56-3.53, p < 0.001), age, BMI, pulse rate, and brain stroke. Conclusion Hyperalbuminemia is significantly associated with increased unscheduled medical visits in rural outpatient settings. Routine serum albumin assessments can aid in risk stratification and personalized care, potentially reducing acute healthcare needs. Future research should explore underlying mechanisms and broader populations to enhance clinical applications.

SH-Alb inhibits phenotype remodeling of pro-fibrotic macrophage to attenuate liver fibrosis through SIRT3-SOD2 axis

Albumin has a variety of biological functions, such as immunomodulatory and antioxidant activity, which depends largely on its thiol activity. However, in clinical trials, the treatment of albumin by injection of commercial human serum albumin (HSA) did not achieve the desired results. Here, we constructed reduced modified albumin (SH-Alb) for in vivo and in vitro experiments to investigate the reasons why HSA did not achieve the expected effects. SH-Alb was found to delay the progression of liver fibrosis in mice by alleviating liver inflammation and oxidative stress. Although R-Alb also has some of the above roles, the effect of SH-Alb is more remarkable. Mechanism studies have shown that SH-Alb reduces the release of pro-inflammatory and pro-fibrotic cytokine through the mitogen-activated protein kinase (MAPK) signaling pathway. In addition, SH-Alb deacetylates SOD2, a key enzyme of mitochondrial reactive oxygen species (ROS) production, by promoting the expression of SIRT3, thereby reducing the accumulation of ROS. Finally, macrophages altered by R-Alb or SH-Alb can inhibit the activation of hepatic stellate cells and endothelial cells, further delaying the progression of liver fibrosis. These results indicate that SH-Alb can remodel the phenotype of macrophages, thereby affecting the intrahepatic microenvironment and delaying the process of liver fibrosis. It provides a good foundation for the application of albumin in clinical treatment.

The Effectiveness of Albumin-to-Globulin Ratio as a Prognostic Biomarker in Primary Gastrointestinal Cancer: A Systematic Review and Meta-Analysis

Albumin-to-globulin ratio (AGR) is a cheap, widely accessible component of common blood work that has been implicated in the prognosis of various cancers. This effect is attributed to the cooperative relationship between albumin reflecting the body's nutritional status and globulin serving as an indicator of immune status. With the high morbidity and mortality associated with gastrointestinal cancer and the increasing necessity for cost-effective health care, research into AGR's potential as an indicator of prognosis is warranted. A database search, including key terms between AGR and gastrointestinal cancer, was performed. Random-effects meta-analysis was completed on extracted hazard ratios with two-sided p-values <0.05 being deemed significant. A total of 8,384 patients with gastrointestinal cancer were included. A low AGR was found to be associated with increased risk for reduced overall survival in cancer of the primary GI tract (HR: 1.82, 1.35-2.45, p < 0.001), esophageal cancer (HR: 1.57, 1.19-2.06, p < 0.001), colon cancer (HR: 3.36, 2.02-5.58, p < 0.001), and colorectal cancer (HR: 2.27, 1.15-4.48, p = 0.02) populations. A low AGR is significantly associated with increased risk for reduced overall survival in primary gastrointestinal cancer. Due to the ease of access and low cost to physicians and patients, incorporation of AGR into clinical evaluation of prognosis in these cancers should prove beneficial to patient outcomes.

Semaphorin 7A promotes endothelial permeability and inflammation via plexin C1 and integrin β1 in Kawasaki disease

BACKGROUND

Kawasaki disease (KD) is a pediatric systemic vasculitis characterized by endothelial cell dysfunction. Semaphorin 7A (Sema7A) has been reported to regulate endothelial phenotypes associated with cardiovascular diseases, while its role in KD remains unknown. This study aims to investigate the effect of Sema7A on endothelial permeability and inflammatory response in KD conditions.

METHODS

Blood samples were collected from 68 KD patients and 25 healthy children (HC). The levels of Sema7A and A Disintegrin and Metalloprotease 17 (ADAM17) in serum were measured by enzyme-linked immunosorbent assay (ELISA), and Sema7A expression in blood cells was analyzed by flow cytometry. Ex vivo monocytes were used for Sema7A shedding assays. In vitro human coronary artery endothelial cells (HCAECs) were cultured in KD sera and stimulated with Sema7A, and TNF-α, IL-1β, IL-6, and IL-18 of HCAECs were measured by ELISA and qRT-PCR. HCAECs monolayer permeability was measured by FITC-dextran.

RESULTS

The serum level of Sema7A was significantly higher in KD patients than in HC and correlated with disease severity. Monocytes were identified as one of the source of elevated serum Sema7A, which implicates a process of ADAM17-dependent shedding. Sera from KD patients induced upregulation of plexin C1 and integrin β1 in HCAECs compared to sera from HC. Sema7A mediated the proinflammatory cytokine production of HCAECs in an integrin β1-dependent manner, while both plexin C1 and integrin β1 contributed to Sema7A-induced HCAEC hyperpermeability.

CONCLUSIONS

Sema7A is involved in the progression of KD vasculitis by promoting endothelial permeability and inflammation through a plexin C1 and integrin β1-dependent pathway. Sema7A may serve as a potential biomarker and therapeutic target in the prognosis and treatment of KD.

A Complex Interplay between Nutrition and Alcohol use Disorder: Implications for Breaking the Vicious Cycle

Approximately 16.5% of the United States population met the diagnostic criteria for substance use disorder (SUD) in 2021, including 29.5 million individuals with alcohol use disorder (AUD). Individuals with AUD are at increased risk for malnutrition, and impairments in nutritional status in chronic alcohol users can be detrimental to physical and emotional well-being. Furthermore, these nutritional deficiencies could contribute to the never-ending cycle of alcoholism and related pathologies, thereby jeopardizing the prospects of recovery and treatment outcomes. Improving nutritional status in AUD patients may not only compensate for general malnutrition but could also reduce adverse symptoms during recovery, thereby promoting abstinence and successful treatment of AUD. In this review, we briefly summarize alterations in the nutritional status of people with addictive disorders, in addition to the underlying neurobiological mechanisms and clinical implications regarding the role of nutritional intervention in recovery from alcohol use disorder.