Ischemia-modified albumin: Crosstalk between fatty acid and cobalt binding

The role of maternal serum ischemia-modified albumin in the prediction of hyperemesis gravidarum: a prospective cohort study

BACKGROUND

Ischemia and associated hypoxemia-induced oxidative stress play an important role in hyperemesis gravidarum (HG) pathogenesis.

OBJECTIVE

The aim was to investigate the role of ischemia-modified albumin (IMA) in predicting HG.

METHODS

A prospective cohort study was conducted with 138 participants with singleton pregnancies who had experienced HG in previous pregnancies. Blood samples were taken at or before 5 weeks, provided they had no symptoms of nausea and vomiting at that time. The samples were stored under appropriate conditions to be analyzed for IMA. All participants were then followed to determine whether they would develop HG.

RESULTS

HG occurred in 42 participants (HG group), while the remaining 96 participants did not develop HG (control group). Baseline characteristics showed no significant differences. IMA levels were significantly higher in the HG group (p < 0.001). IMA levels did not correlate with body mass index or maternal age. IMA with a cut-off of >74.74 ng/mL (95% sensitivity, 67% specificity) had a discriminatory power with an AUC value of 0.791 (95% CI: 0.714-0.856; p < 0.001) for predicting HG.

CONCLUSION

Our results show an association between high IMA levels in early pregnancy and an increased risk of HG. IMA can be used as a predictive tool for HG.

Fatty acid influence on zinc and uranyl ion binding to human serum albumin: an all atoms molecular dynamics investigation

The potential health risks associated with radionuclides, particularly actinides, have prompted investigations into their interactions with body fluids in living organisms. Human serum albumin (HSA), a plenteous plasma protein with extraordinary binding capacities, is a key player in these interactions. The present study is intended at understanding the interplay between metal ions, namely, zinc and uranyl ions and fatty acids binding with HSA, using all atom equilibrium and non-equilibrium molecular dynamics simulations. Results highlight distinct behaviours of zinc and uranyl ions, elucidating how their interactions with HSA are influenced by the presence of fatty acids. Hydrogen bonding dynamics analysis reveals the disruption of existing bonds due to fatty acid binding, contrasting with the weakening effect caused by metal binding. The resulting conformational changes have significant implications for HSA's structure and dynamics. The potential of mean force (PMF) plots reveals binding and unbinding routes for zinc and uranyl ions, both in fatty acid's presence and absence. Short-range interactions reveal distinct binding behaviours of zinc and uranyl ions, altered by fatty acids, providing insights into unbinding pathways and correlating with the PMF plots.

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.

An Update Overview on Mechanistic Data and Biomarker Levels in Cobalt and Chromium-Induced Neurodegenerative Diseases

There is increasing evidence that the imbalance of metals as cobalt (Co) and chromium (Cr) may increase the risk of development and progression of neurodegenerative diseases (NDDs). The human exposure to Co and Cr is derived mostly from industry, orthopedic implants, and polluted environments. Neurological effects of Co and Cr include memory deficit, olfactory dysfunction, spatial disorientation, motor neuron disease, and brain cancer. Mechanisms of Co and Cr neurotoxicity included DNA damage and genomic instability, epigenetic changes, mitochondrial disturbance, lipid peroxidation, oxidative stress, inflammation, and apoptosis. This paper seeks to overview the Co and Cr sources, the mechanisms by which these metals induce NDDs, and their levels in fluids of the general population and patients affected by NDDs. To this end, evidence of Co and Cr unbalance in the human body, mechanistic data, and neurological symptoms were collected using in vivo mammalian studies and human samples.

Multi-cavity molecular descriptor interconnections: Enhanced protocol for prediction of serum albumin drug binding

The role of human serum albumin (HSA) in the transport of molecules predicates its involvement in the determination of drug distribution and metabolism. Optimization of ADME properties are analogous to HSA binding thus this is imperative to the drug discovery process. Currently, various in silico predictive tools exist to complement the drug discovery process, however, the prediction of possible ligand-binding sites on HSA has posed several challenges. Herein, we present a strong and deeper-than-surface case for the prediction of HSA-ligand binding sites using multi-cavity molecular descriptors by exploiting all experimentally available and crystallized HSA-bound drugs. Unlike previously proposed models found in literature, we established an in-depth correlation between the physicochemical properties of available crystallized HSA-bound drugs and different HSA binding site characteristics to precisely predict the binding sites of investigational molecules. Molecular descriptors such as the number of hydrogen bond donors (nHD), number of heteroatoms (nHet), topological polar surface area (TPSA), molecular weight (MW), and distribution coefficient (LogD) were correlated against HSA binding site characteristics, including hydrophobicity, hydrophilicity, enclosure, exposure, contact, site volume, and donor/acceptor ratio. Molecular descriptors nHD, TPSA, LogD, nHet, and MW were found to possess the most inherent capacities providing baseline information for the prediction of serum albumin binding site. We believe that these associations may form the bedrock for establishing a solid correlation between the physicochemical properties and Albumin binding site architecture. Information presented in this report would serve as critical in provisions of rational drug designing as well as drug delivery, bioavailability, and pharmacokinetics.

Association of Ischemia-Modified Albumin (IMA) in Saliva, Serum, and Urine with Diagnosis of Chronic Kidney Disease (CKD) in Children: A Case-Control Study

BACKGROUND Ischemia-modified albumin (IMA) is a secreted biomarker for ischemic oxidative stress. This case-control study aimed to evaluate the association of ischemia-modified albumin (IMA) in saliva, serum, and urine with diagnosis of chronic kidney disease (CKD) in 24 children. MATERIAL AND METHODS The study involved 24 children with CKD. CKD was defined according to the Kidney Disease Improving Global Outcomes (KDIGO) diagnostic criteria. The control group consisted of 24 healthy children who were matched for age and gender to the experimental group. The concentration of IMA was determined by the colorimetric method in non-stimulated whole saliva (NWS), stimulated whole saliva (SWS), serum, and urine of children with CKD. The Mann-Whitney U test was used for inter-group comparisons. RESULTS IMA levels were significantly higher in NWS (P=0.0082) and SWS (P=0.0014) of children with CKD than in the control group. The concentration of IMA in NWS was correlated with standard indicators of kidney function, including the estimated glomerular filtration rate (r=-0.798, P≤0.0001), stage of CKD (r=0.814, P≤0.0001), and serum creatinine (r=0.711, P≤0.0001) and urea levels (r=0.738, P≤0.0001). CONCLUSIONS Salivary IMA concentration depends on renal function in children. Salivary IMA discriminates children with end-stage kidney disease from children with mild and moderate CKD and healthy children with high sensitivity and specificity. Further research is required, including assessment of the diagnostic usefulness and validation of the biomarker in a clinical diagnostic study.

Differential Spectrum of Albumin Glycation, Oxidation, and Truncation in Type 2 and Type 1 Diabetes: Clinical and Biological Implications

Background: Albumin, the most abundant and physiologically vital serum protein, accumulates a range of chemical modifications, as consequence of encounters with large number of reactive molecules whose concentrations increase in serum under pathological conditions. Methods: In a "proof of concept" study, mass spectrometric analysis was utilized to quantitate albumin post-translational modifications (glycation, oxidation, and truncation; individual isoforms and total) in four informative subject groups [type 1 diabetes (T1DM), type 2 diabetes (T2DM), prediabetes-obesity and healthy; all with estimated glomerular filtration rate ≥60 mL/(min·m2)]. Besides glycated albumin (GA/mass spectrometry), glycated serum protein (GSP/nitro blue tetrazolium colorimetry), and glycated hemoglobin (HbA1c/high-performance liquid chromatography) were also measured. Results: A wide spectrum of albumin molecular modifications was identified in diabetes, with significant differences between T2DM and T1DM. Albumin glycation: GA correlated more strongly with HbA1c in T1DM, compared to T2DM. Higher albumin glycation isoforms (human serum albumin +3G/2G) were more stable and discriminative markers of mean glycemia. Albumin oxidation: T2DM, in comparison with T1DM, showed enhanced oxidative and dual (glycation plus oxidation) modifications, representing extreme molecular pathology. Albumin truncation: There was dramatic reduction ("deficiency") of truncated albumin isoforms in T2DM, and significant reduction in T1DM. Albumin truncation negatively correlated with severity of albumin glycation (mean glycemia) and albumin oxidation (cysteinylation). Possible mechanisms of insulin resistance, with associated increased free fatty acids binding to albumin, in stimulating albumin oxidation and inhibiting albumin glycation ("metabolic cross talks") are reviewed. Conclusions: Albumin molecular modifications in diabetes, together with significant differences between T2DM and T1DM, suggest possible role for insulin resistance in their genesis and consequent cell, tissue, and vascular dysfunction/damage. Albumin molecular fingerprinting can provide valuable insights into pathogenesis, diagnosis, monitoring, and future therapies for diabetes. Identification of biomarker battery ("albuminomics," "diabetomics") driven diverse "healthy," prediabetes, obesity, and T2DM phenotypes represents additional novel step toward precision medicine in diabetes and related disorders.

Novel insights about albumin in cardiovascular diseases: Focus on heart failure

The Human Plasma Proteome has always been the most investigated compartment in proteomics-based biomarker discovery, and is considered the largest and deepest version of the human proteome, reflecting the state of the body in health and disease. Even if efforts have been always dedicated to the refinement of proteomic approaches to investigate more deeply the plasma proteome, it should not be forgotten that also highly abundant plasma proteins, like human serum albumin (HSA), often neglected in these studies, might provide fundamental physiological functions in plasma, and should be better considered. This review summarizes the important roles of HSA in the context of cardiovascular diseases (CVD), and in particular in heart failure. Notwithstanding much attention has been historically directed toward the association of HSA levels and CVD risk, the advances in the field of mass spectrometry research allow also a better characterization of the effects of oxidative modifications that could alter not only the structure but also the function of HSA.

Markers of Oxidative Stress in Patients with Acne: A Literature Review

Acne vulgaris is a chronic inflammatory skin disease of the pilosebaceous unit. Its pathogenesis is multifactorial and involves the overlap between four main processes: alteration of the keratinization, increased sebum production, colonization with Cutibacterium acnes, and inflammation. The role of oxidative stress (OS) has been intensively studied in inflammatory skin conditions such as psoriasis, vitiligo, or atopic dermatitis. However, the involvement of OS in the pathogenesis of acne is less known. The evidence accumulated over the last decade suggests that in the case of acne patients, there is an imbalance between oxidants and antioxidants. In this review, we analyzed studies that evaluated markers of OS in patients with acne, published in the last ten years, with the aim of providing new insights into the pathogenesis of acne.

Structural and biochemical characterisation of Co2+-binding sites on serum albumins and their interplay with fatty acids

Serum albumin-Co²⁺ interactions are of clinical importance. They play a role in mediating the physiological effects associated with cobalt toxicity and are central to the albumin cobalt binding (ACB) assay for diagnosis of myocardial ischemia. To further understand these processes, a deeper understanding of albumin-Co²⁺ interactions is required. Here, we present the first crystallographic structures of human serum albumin (HSA; three structures) and equine serum albumin (ESA; one structure) in complex with Co²⁺. Amongst a total of sixteen sites bearing a cobalt ion across the structures, two locations were prominent, and they relate to metal-binding sites A and B. Site-directed mutagenesis and isothermal titration calorimetry (ITC) were employed to characterise sites on HSA. The results indicate that His9 and His67 contribute to the primary (putatively corresponding to site B) and secondary Co²⁺-binding sites (site A), respectively. The presence of additional multiple weak-affinity Co²⁺ binding sites on HSA was also supported by ITC studies. Furthermore, addition of 5 molar equivalents of the non-esterified fatty acid palmitate (C16:0) reduced the Co²⁺-binding affinity at both sites A and B. The presence of bound myristate (C14:0) in the HSA crystal structures provided insight into the fatty acid-mediated structural changes that diminish the affinity of the protein toward Co²⁺. Together, these data provide further support for the idea that ischemia-modified albumin corresponds to albumin with excessive fatty-acid loading. Collectively, our findings provide a comprehensive understanding of the molecular underpinnings governing Co²⁺ binding to serum albumin.

Evaluation of Serum Ischemia Modified Albumin in Patients With COVID-19 Pneumonia: A Case-Control Study

Introduction: Various biomarkers are used when evaluating the hospitalization needs of patients diagnosed with Coronavirus disease (COVID-19). Ischemia-modified albumin (IMA) is a biomarker that causes blood levels to increase as a result of hypoxia and acidosis. We think that an increase in IMA in the blood may be caused by hypoxia stemming from lung damage. This study aimed to compare the mean/median of the blood IMA value in patients with pneumonia due to COVID-19 infection with a control group.

Methods: The case group included patients with COVID-19 pneumonia detected by lung imaging and a positive COVID test. Demographic information of the case group, the severity of pneumonia, and their PCR test results were recorded in the data set.

Findings: A total of 150 people, 90 of whom were in the case group and 60 of whom were in the control group, participated in the study. No statistically significant differences were found between the blood IMA levels of the case group and the control group. When the blood IMA levels of the case group were compared according to pneumonia severity, no statistically significant differences were found between the mild-moderate and severe pneumonia groups.

Conclusion: Blood IMA levels are not a diagnostic biomarker for patients with COVID-19 pneumonia and are not helpful in predicting the severity of pneumonia.

Comparison of thiol disulfide values in the cord blood of patients undergoing cesarean section under spinal or general anesthesia

Background/Aim: Oxidative stress is known to increase in patients receiving anesthesia before undergoing surgery. Since newborns are more sensitive to oxygen-free radicals, the effects and characteristics of anesthesia methods that are used for pregnant women require analysis. This study aimed to evaluate the effects of spinal and general anesthesia on oxidative stress by investigating thiol disulfide and ischemia modified albumin (IMA) concentrations in the cord blood of patients undergoing cesarean section (C-section) via spinal or general anesthesia. Methods: This cross-sectional prospective study included 60 patients who were indicated for elective cesarean section. Patients with chronic disease, pregnancy complications and/or required emergency cesareans were not included. Group 1 (n = 30) underwent general anesthesia, and Group 2 (n = 30) underwent spinal anesthesia during their C-sections. Thiol–disulfide levels were evaluated concurrently in all blood samples taken from the umbilical artery remaining on the placental side. Results: The mean age (SD) of the mothers was 30.6 (4.4) years and the mean gestational age (SD) was 39.0 (0.9) weeks. Gestational age, birth weight, and first and fifth min Apgar scores of the two groups were similar. The mean (SD) native thiol (362.4 [63.8]; 323.2 [45.8]), total thiol (409.6 [70.2]; 363.5 [46.1]), and disulfide values (23.6 (5.4); 20.2 (4.3)) were significantly higher in group 1 than group 2, while the median (interquartile range [IQR]) values of IMA (0.89 (0.85-max 0.92); 0.85 (min 0.82-max 0.879) were significantly higher in group 2 than group 1 (P < 0.05). Conclusions: As general anesthesia may cause a higher degree of oxidative stress, selecting the appropriate anesthetic technique may be especially important for risky pregnancies in which increased oxidative stress in the mother and baby may be critical for the outcome.

Albumin-mediated extracellular zinc speciation drives cellular zinc uptake

The role of the extracellular medium in influencing metal uptake into cells has not been described quantitatively. In a chemically-defined model system containing albumin, zinc influx into endothelial cells correlates with the extracellular free zinc concentration. Allosteric inhibition of zinc-binding to albumin by free fatty acids increased zinc flux.

Fatty acids alter zinc speciation in plasma, increasing zinc influx into endothelial cells.

Ischemia-Modified Albumin—A Potential New Marker of Oxidative Stress in Dermatological Diseases

There is growing evidence that oxidative stress is involved in the pathogenesis of numerous conditions, including dermatological diseases. Various markers are available to assess oxidative stress, but none of these can be considered the ideal marker. Recent studies have shown that ischemia-modified albumin (IMA) is not only an indicator of ischemia, but also a marker of oxidative stress. We have conducted a narrative review to evaluate the role of IMA in dermatological diseases. We have identified 24 original articles that evaluated IMA in skin disorders (psoriasis, acne vulgaris, hidradenitis suppurativa, urticaria, vitiligo and Behcet’s disease) and hair disorders (alopecia areata, androgenetic alopecia and telogen effluvium). The results of the studies analyzed reveal that IMA may be considered a new marker of oxidative stress in dermatological diseases and offer new insights into the pathogenesis of these disorders and the theoretical basis for the development of new, effective, targeted therapies. To the best of our knowledge, this is the first review that gathers up data on the role of IMA in dermatological diseases.

Oxidative Stress Biomarkers in Age-Related Lower Urinary Tract Disorders: A Systematic Review

PURPOSE

To conduct a systematic review of preclinical and clinical peer-reviewed evidence linking alterations in oxidative stress biomarkers or outcome measures that were also prevalent in specific age-related lower urinary tract (LUT) disorders.

METHODS

PubMed, Scopus, CINAHL, and Embase were searched for peer-reviewed studies published between January 2000 and March 2021. Animal and human studies that reported on the impact of oxidative stress in age-related LUT disorders through structural or functional changes in the LUT and changes in biomarkers were included. The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) protocol was followed.

RESULTS

Of 882 articles identified, 21 studies (13 animal; 8 human) met inclusion criteria. Across LUT disorders, common structural changes were increased bladder and prostate weights, ischemic damage, nerve damage and detrusor muscle hypertrophy; common functional changes included decreased bladder contraction, increased bladder sensation and excitability, decreased perfusion, and increased inflammation. The disorders were associated with increased levels of biomarkers of oxidative stress that provided evidence of either molecular damage, protective mechanisms against oxidative stress, neural changes, or inflammation. In all cases, the effect on biomarkers and enzymes was greater in aged groups compared to younger groups.

CONCLUSION

Increased oxidative stress, often associated with mitochondrial dysfunction, plays a significant role in the pathogenesis of age-related LUT disorders and may explain their increasing prevalence. This systematic review identifies potential markers of disease progression and treatment opportunities; further research is warranted to evaluate these markers and the mechanisms by which these changes may lead to age-related LUT disorders.

Is ischaemia-modified albumin a biomarker in wagner classification in diabetic foot ulcers?

BACKGROUND

We aimed to determine the relationship of ischaemia-modified albumin (IMA) with diabetic foot ulcers and its predictive value in the Wagner classification.

METHODS

Our cross-sectional study was conducted in 120 diabetic foot patients and 60 healthy individuals with similar body mass index (BMI) and age. Patients with a diabetic foot were classified according to the Wagner classification. Biochemical parameters, C-reactive protein (CRP) and IMA levels were measured in all patients and healthy volunteers. Screening performance characteristics of CRP and IMA were calculated according to Wagner classes and the presence of osteomyelitis.

RESULTS

The levels of BMI, CRP and IMA in diabetic foot patients were significantly higher than the healthy controls. When we grouped the patients according to the Wagner classification, there were no significant differences between the Wagner groups in terms of BMI. The highest IMA levels were detected in Wagner grade 5. CRP had higher sensitivity and specificity than IMA in the discrimination of other grades, except for grade 4-5 separation. For Wagner grade 4-5 distinction, IMA had 84.6% sensitivity and 94.7% specificity.

CONCLUSION

IMA had a higher predictive value in discrimination of the Wagner grade 4-5. In the management of diabetic foot patients, it may be recommended that IMA is evaluated by clinicians.

Neutrophil-mediated oxidative stress and albumin structural damage predict COVID-19-associated mortality

Human serum albumin (HSA) is the frontline antioxidant protein in blood with established anti-inflammatory and anticoagulation functions. Here, we report that COVID-19-induced oxidative stress inflicts structural damages to HSA and is linked with mortality outcome in critically ill patients. We recruited 39 patients who were followed up for a median of 12.5 days (1–35 days), among them 23 had died. Analyzing blood samples from patients and healthy individuals (n=11), we provide evidence that neutrophils are major sources of oxidative stress in blood and that hydrogen peroxide is highly accumulated in plasmas of non-survivors. We then analyzed electron paramagnetic resonance spectra of spin-labeled fatty acids (SLFAs) bound with HSA in whole blood of control, survivor, and non-survivor subjects (n=10–11). Non-survivors’ HSA showed dramatically reduced protein packing order parameter, faster SLFA correlational rotational time, and smaller S/W ratio (strong-binding/weak-binding sites within HSA), all reflecting remarkably fluid protein microenvironments. Following loading/unloading of 16-DSA, we show that the transport function of HSA may be impaired in severe patients. Stratified at the means, Kaplan–Meier survival analysis indicated that lower values of S/W ratio and accumulated H₂O₂ in plasma significantly predicted in-hospital mortality (S/W≤0.15, 81.8% (18/22) vs. S/W>0.15, 18.2% (4/22), p=0.023; plasma [H₂O₂]>8.6 μM, 65.2% (15/23) vs. 34.8% (8/23), p=0.043). When we combined these two parameters as the ratio ((S/W)/[H₂O₂]) to derive a risk score, the resultant risk score lower than the mean (<0.019) predicted mortality with high fidelity (95.5% (21/22) vs. 4.5% (1/22), log-rank χ²=12.1, p=4.9×10⁻⁴). The derived parameters may provide a surrogate marker to assess new candidates for COVID-19 treatments targeting HSA replacements and/or oxidative stress.

Increase in Ischemia-Modified Albumin and Pregnancy-Associated Plasma Protein-A in COVID-19 Patients

This study was undertaken due to the urgent need to explore reliable biomarkers for early SARS-CoV-2 infection. We performed a retrospective study analyzing the serum levels of the cardiovascular biomarkers IL-6, TNF-α, N-terminal pro-B natriuretic peptide, cardiac troponin T (cTnT), ischemia-modified albumin (IMA) and pregnancy-associated plasma protein-A (PAPP-A) in 84 patients with COVID-19.Patients were divided into three groups according to their RT-qPCR and IgG values: acute infection (n = 35), early infection (n = 25) or control subjects (n = 24). Levels of biomarkers were analyzed in patient serum samples using commercially available ELISA kits. Results showed a significant increase in IMA and PAPP-A levels in the early infected patients. Moreover, multivariate analysis and receiver operating characteristic (ROC) curve showed that IMA and PAPP-A had excellent discrimination value for the early stage of COVID-19. For IMA, the area under the ROC curve (AUC) had a value of 0.94 (95% confidence interval (CI): 0.881–0.999). Likewise, the serum level of PAPP-A was significantly higher in patients with early infection than in the control subjects (AUC = 0.801 (95% CI: 0.673–0.929)). The combined use of IMA and PAPP-A enhanced the sensitivity for total SARS-CoV-2-infected patients to 93%. These results suggest that the increased levels of PAPP-A and IMA shed light on underlying mechanisms of COVID-19 physiopathology and might be used as efficient biomarkers with high sensitivity and specificity for the early stage of COVID-19. Importantly, when monitoring pregnancy and cardiovascular diseases using PAPP-A or IMA levels, a SARS-CoV-2 infection should be discarded for proper interpretation of the results.

Albumin Substitution in Decompensated Liver Cirrhosis: Don't Forget Zinc

Decompensated liver cirrhosis has a dismal prognosis, with patients surviving on average for 2-4 years after the first diagnosis of ascites. Albumin is an important tool in the therapy of cirrhotic ascites. By virtue of its oncotic properties, it reduces the risk of cardiovascular dysfunction after paracentesis. Treatment with albumin also counteracts the development of hepatorenal syndrome and spontaneous bacterial peritonitis. More recently, the positive impact of long-term albumin supplementation in liver disease, based on its pleiotropic non-oncotic activities, has been recognized. These include transport of endo- and exogenous substances, anti-inflammatory, antioxidant and immunomodulatory activities, and stabilizing effects on the endothelium. Besides the growing recognition that effective albumin therapy requires adjustment of the plasma level to normal physiological values, the search for substances with adjuvant activities is becoming increasingly important. More than 75% of patients with decompensated liver cirrhosis do not only present with hypoalbuminemia but also with zinc deficiency. There is a close relationship between albumin and the essential trace element zinc. First and foremost, albumin is the main carrier of zinc in plasma, and is hence critical for systemic distribution of zinc. In this review, we discuss important functions of albumin in the context of metabolic, immunological, oxidative, transport, and distribution processes, alongside crucial functions and effects of zinc and their mutual dependencies. In particular, we focus on the major role of chronic inflammatory processes in pathogenesis and progression of liver cirrhosis and how albumin therapy and zinc supplementation may affect these processes.

Ischemia-Modified Albumin: Origins and Clinical Implications

Albumin is one of the most abundant proteins in the body of mammals: about 40% of its pool is located in the intravascular space and the remainder is found in the interstitial space. The content of this multifunctional protein in blood is about 60-65% of total plasma proteins. A decrease in its synthesis or changes of functional activity can destabilize oncotic blood pressure, cause a violation of transporting hormones, fatty acids, metals, and drugs. Albumin properties change under ischemic attacks associated with oxidative stress, production of reactive oxygen species, and acidosis. Under these conditions, ischemia-modified albumin (IMA) is generated that has a reduced metal-binding capacity, especially for transition metals, such as copper, nickel, and cobalt. The method of determining the cobalt-binding capability of HSA was initially proposed to evaluate IMA level and then licensed as an ACB test for routine clinical analysis for myocardial ischemia. Subsequent studies have shown the viability of the ACB test in diagnosing other diseases associated with the development of oxidative stress. This review examines recent data on IMA generation mechanisms, describes principles, advantages, and limitations of methods for evaluation of IMA levels, and provides detailed analysis of its use in diagnostic and monitoring therapeutic efficacy in different diseases.

The effects of iron overload, insulin resistance and oxidative stress on metabolic disorders in patients with β- thalassemia major

Background

Serum lipids and glycemic dysregulation are the known characteristics of β- thalassemia major (β-TM). Here, we evaluated the association of these disorders with insulin resistance (IR), oxidative stress and serum ferritin values in patients with β-TM.

Methods

This case-control study was performed in thalassemia unite of Darab Hospital (Darab, Fars province, Iran) from December 2016 to December 2017. Forty-eight patients with β-TM and 33 healthy individuals were enrolled. Serum fasting blood sugar (FBS), insulin, total cholesterol (TC), triglyceride (TG), high density lipoprotein (HDL), low density lipoprotein (LDL), ischemia modified albumin (IMA), and ferritin were measured. The values of HOMA-IR, LDL: TG ratio, atherogenic index (AI), atherogenic index of plasma (AIP), and coronary risk index (CRI) were calculated.

Results

The level of serum ferritin, IMA, FBS, TG, AIP, LDL: TG ratio, and the prevalence of IR (HOMA-IR < 3.8) were significantly higher while TC, LDL-C, HDL-C, and AI were significantly lower in the patients compared to the control group. In patient with β-TM, serum ferritin revealed to have a positive association with serum insulin, HOMA-IR, AI, and CRI levels while serum IMA showed positive association with TG and AIP and inverse association with hypocholesterolemia. HOMA-IR had positive correlation with HDL levels.

Conclusions

Oxidative stress and iron overload are predictors of serum glycemic and lipid dysregulation, suggesting possible beneficial effect of antioxidants and efficient iron chelating therapy in reducing the risk of metabolic disorders in β- thalassemia.

Intestinal fatty acid-binding protein as a biomarker for the diagnosis of strangulated intestinal obstruction: A meta-analysis

Objective

The purpose of this study was to clarify the value of intestinal fatty acid-binding protein (I-FABP) for the early diagnosis of strangulated intestinal obstruction through a meta-analysis.

Methods

A search was performed on PubMed, EBSCO, the Cochrane Library, the Web of Science, EMBASE, CNKI, and WanFang for studies on the diagnosis of strangulated intestinal obstruction based on I-FABP. Endnote X9 software and the quality assessment of diagnostic accuracy studies 2 (QUADAS-2) were used to screen the studies and evaluate their quality, respectively. Meta-Disc 1.4 and Stata 15.1 software were used to perform the assessment of heterogeneity and meta-analysis.

Result

A total of eight studies were included, Spearman correlation coefficient was 0.703 (P = 0.078), suggesting that there was no threshold effect. The pooled results of the meta-analysis were as follows: sensitivity: 0.75 (95% CI: 0.66–0.81), specificity: 0.83 (95% CI: 0.71–0.91), positive likelihood ratio (PLR): 4.35 (95% CI: 2.57–7.36), negative likelihood ratio (NLR): 0.31 (95% CI: 0.24–0.39), and diagnostic odds ratio (DOR): 14.19 (95% CI: 8.08–24.92). The area under the curve was 0.83. There was obvious heterogeneity among the studies.

Conclusion

I-FABP is very valuable for the early diagnosis of strangulated intestinal obstruction and can be used to distinguish strangulated intestinal obstruction from intestinal obstruction in a timely manner, enabling accurate planning of the timing of surgery.

Alterations in Blood Metabolic Parameters of Immature Mice After Subchronic Exposure to Cobalt Chloride

The wide use of cobalt (Co) in food, industry, and medical devices requires full elucidation of its biological effects on tissues and organs. The aim was to assess serum metabolic alterations in immature mice after subchronic exposure to CoCl₂. Pregnant ICR mice were subjected to a daily dose of 75 mg cobalt chloride/kg body weight (CoCl₂x6H₂O) 2-3 days before they gave birth, and treatment continued until days 25 and 30 after delivery. The compound was dissolved in and obtained with regular tap water. ICP-DRC-MS analysis showed significantly elevated serum Co²⁺ and diverse alterations in metabolic parameters of 25- and 30-day-old pups after exposure to CoCl₂. Cholesterol and urea levels were significantly elevated in day 25 mice while HDL-C and LDL-C were reduced. In day 30, Co-exposed mice LDL-C and triglycerides were significantly increased while the total cholesterol level remained unchanged. Alkaline phosphatase was significantly reduced in day 25 Co-exposed mice. Blood glucose level of Co-exposed mice remained close to the untreated controls. Total protein content was slightly increased in day 30 mice. Co-exposure reduced albumin content and albumin/globulin ratio but increased significantly globulin content. Co administration showed strong correlation with cholesterol, urea, and HDL-C in both day 25 and 30 mice. Inverse correlation was found with alkaline phosphatase and albumin for day 25 and with triglycerides, globulin, and total protein content in day 30 Co-exposed mice. Subchronic CoCl₂ exposure of immature mice induced significant changes in key metabolic parameters suggesting possible further disturbances in energy metabolism, osteogenesis, and reproduction.

Novel Invasive and Noninvasive Cardiac-Specific Biomarkers in Obesity and Cardiovascular Diseases

Cardiovascular disease (CVD) is the leading cause of fatality and disability worldwide regardless of gender. Obesity has reached epidemic proportions in population across different regions. According to epidemiological studies, CVD risk markers in childhood obesity are one of the significant risk factors for adulthood CVD, but have received disproportionally little attention. This review has examined the evidence for the presence of traditional cardiac biomarkers (nonspecific; lactate dehydrogenase, alanine aminotransferase, aspartate aminotransferase, creatine kinase, myoglobulin, glycogen phosphorylase isoenzyme BB, myosin light chains, ST2, and ischemia-modified albumin) and novel emerging cardiac-specific biomarkers (cardiac troponins, natriuretic peptides, heart-type fatty acid-binding protein, and miRNAs). Besides, noninvasive anatomical and electrophysiological markers (carotid intima-media thickness, coronary artery calcification, and heart rate variability) in CVDs and obesity are also discussed. Modifiable and nonmodifiable risk factors associated with metabolic syndrome in the progression of CVD, such as obesity, diabetes, hypertension, dyslipidemia, oxidative stress, inflammation, and adipocytokines are also outlined. These underlying prognostic risk factors predict the onset of future microvascular and macrovascular complications. The understanding of invasive and noninvasive cardiac-specific biomarkers and the risk factors may yield valuable insights into the pathophysiology and prevention of CVD in a high-risk obese population at an early stage.

Impaired albumin function: a novel potential indicator for liver function damage?

Albumin is the most abundant plasma protein and albumin infusion is commonly used. Conventionally, the biologic and therapeutic effects of albumin have been thought to be due to its oncotic properties. However, albumin has a variety of biologic functions, including molecular transport, anti-oxidation, anti-inflammation, endothelial stabilisation, anti-thrombotic effects, and the adjustment of capillary permeability. Despite this, the functions of albumin have not been thoroughly investigated. Recent studies have shown non-alcoholic fatty liver disease (NAFLD), viral hepatitis, cirrhosis, and liver failure to be associated with impairments in albumin function, which are associated with impairments in liver function and disease prognosis. Post-translational modifications of albumin cause structural modifications that affect protein function. Recently, the concentration of albumin associated with normal function, the 'efficient albumin concentration', has been attracting more interest. In addition, although many biologic markers, including albumin concentration, are widely used for the assessment of early liver dysfunction in patients with liver diseases, the predictive values are unsatisfactory. However, clinical evidence has suggested that albumin function may represent a novel biomarker of early impairment in liver function. In this review, we summarise the factors affecting albumin function and discuss the clinical significance of impairments in albumin function in various liver diseases.Key messagesThe importance of albumin depends not only on its concentration, but also on its various physiological functions.Impaired albumin function has been reported in a variety of liver diseases, and is associated with disease severity and prognosis, thereby proposing the concept of 'effective albumin concentration'.Albumin dysfunction occurs earlier than other conventional indicators, and albumin dysfunction may be a new biomarker of early impairment in liver function.Many exogenous and endogenous factors lead to post-translational modifications of albumin, which alters the three-dimensional structure of albumin, resulting in a decrease in its biological activity.

Role of Ischemia Modified Albumin Serum Levels as an Oxidative Stress Marker in Children with Diabetic Ketoacidosis

AIM AND OBJECTIVE

Ischemia modified albumin (IMA) is a biomarker that has been introduced recently for use in the evaluation of oxidative stress. The aim of this study was to measure the ischemia modified albumin serum levels in pediatric patients with diabetic ketoacidosis (DKA) during acidosis and after the patient recovered from acidosis and to compare these with the control group.

MATERIALS AND METHODS

Pediatric patients with Type I diabetes mellitus (T1DM) who were admitted to the pediatric intensive care unit with the diabetic ketoacidosis were assigned as the study group and healthy children who were admitted to the outpatient clinic and decided as healthy after clinic and laboratory evaluation were selected as the control group. IMA and adjusted IMA levels were evaluated in the blood samples from the control group and the study group when admitted first time to the intensive care unit during the acidosis period (DKA before treatment, DKA-BT), and after recovering from acidosis (DKA after treatment, DKA-AT).

RESULTS

A total of 24 pediatric patients with diabetic ketoacidosis and 30 healthy control children matching age and sex were included in the current study. The albumin levels in pediatric patients with T1DM during DKA-BT were higher than the albumin levels after acidosis (4.101±0.373, 3.854±0.369 g/dL, respectively) (p<0.05). However, there was no significant difference when these values were compared to the control group. Mean values of IMA and Adj-IMA were statistically higher in DKAAT compared to the control group (0.748±0.150 vs 0.591±0.099, p< 0.001; 0.708±0.125 vs 0.607±0.824, p< 0.001, respectively). IMA and adjusted IMA levels measured after recovered from acidosis were significantly higher compared to the level of IMA during DKA (0.748±0.150 vs 0.606±0.105 as absorbance unit, p<0.001; 0.708±0.125 vs 0.625±0.100, p<0.05, respectively).

CONCLUSION

In children with T1DM, even though acidosis recovered following the treatment in diabetic ketoacidosis, which is an oxidative stress marker, the ischemia modified albumin levels and adjusted ischemia modified albumin levels were high.

Ischemia-modified Albumin as a Biomarker for Prediction of Poor Outcome in Patients With Traumatic Brain Injury: An Observational Cohort Study

BACKGROUND

Biomarkers can assist in outcome prediction and therapeutic decision making after traumatic brain injury (TBI). The aim of this study was to evaluate the role of ischemia-modified albumin (IMA) in the prediction of mortality in patients with TBI.

METHODS

In this observational study IMA was measured on admission to intensive care unit (D0) and 24 hours later (D1) in a cohort of patients with mixed TBI severity. The primary outcome was the correlation between IMA and 28-day mortality. Secondary outcomes included the incidence of elevated IMA, and the correlation between the severity of TBI and IMA, and between IMA and change in Glasgow coma score (GCS). The area under receiver operating characteristic curve analysis was performed to detect optimal IMA cut-off value for the detection of mortality.

RESULTS

Fifty-four patients were included in the study; IMA was elevated in 49 (90.7%) on admission to the intensive care unit. Of the 49 patients with elevated IMA, 22 had a decrease in IMA while 27 had an increase by 24 hours. IMA levels were higher at D0 and D1 (P<0.001 for both) in patients who died compared with those who survived. Twenty-one patients died (mortality rate 38.9%); all had elevated IMA on D0 and D1 and higher IMA levels at D1 compared with D0. Optimal cut-off values for IMA predicted mortality with 76.2% sensitivity and 81.8% specificity at D0 and with 100% sensitivity and specificity at D1. IMA values at D0 and D1 were correlated with D0 and D1 GCS, respectively (both P<0.001).

CONCLUSION

IMA levels were elevated in patients following TBI, and can predict mortality with high sensitivity and specificity.

Towards the functional high-resolution coordination chemistry of blood plasma human serum albumin

Human serum albumin (HSA) is a monomeric, globular, multi-carrier and the most abundant protein in the blood. HSA displays multiple ligand binding sites with extraordinary binding capacity for a wide range of ions and molecules. For decades, HSA's ability to bind to various ligands has led many scientists to study its physiological properties and protein structure; indeed, a better understanding of HSA-ligand interactions in human blood, at the atomic level, will likely foster the development of more potent, and overall more performant, diagnostic and therapeutic tools against serious human disorders such as diabetes, cardiovascular disorders, and cancer. Here, we present a concise overview of the current knowledge of HSA's structural characteristics, and its coordination chemistry with transition metal ions, within the scope and limitations of current techniques and biophysical methods to reach atomic resolution in solution and in blood serum. We also highlight the overwhelming need of a detailed atomistic understanding of HSA dynamic structures and interactions that are transient, weak, multi-site and multi-step, and allosterically affected by each other. Considering the fact that HSA is a current clinical tool for drug delivery systems and a potential contender as molecular cargo and nano-vehicle used in biophysical, clinical and industrial fields, we underline the emerging need for novel approaches to target the dynamic functional coordination chemistry of the human blood serum albumin in solution, at the atomic level.

Crosstalk between zinc and free fatty acids in plasma

In mammalian blood plasma, serum albumin acts as a transport protein for free fatty acids, other lipids and hydrophobic molecules including neurodegenerative peptides, and essential metal ions such as zinc to allow their systemic distribution. Importantly, binding of these chemically extremely diverse entities is not independent, but linked allosterically. One particularly intriguing allosteric link exists between free fatty acid and zinc binding. Albumin thus mediates crosstalk between energy status/metabolism and organismal zinc handling. In recognition of the fact that even small changes in extracellular zinc concentration and speciation modulate the function of many cell types, the albumin-mediated impact of free fatty acid concentration on zinc distribution may be significant for both normal physiological processes including energy metabolism, insulin activity, heparin neutralisation, blood coagulation, and zinc signalling, and a range of disease states, including metabolic syndrome, cardiovascular disease, myocardial ischemia, diabetes, and thrombosis.

•

Serum albumin binds and transports both free fatty acids and Zn²⁺ ions

•

Elevated plasma free fatty acids impair Zn²⁺ binding by albumin through an allosteric mechanism

•

The resulting changes in plasma zinc speciation are thought to impact blood coagulation and may promote thrombosis

•

Increased free Zn²⁺ may lead to enhanced zinc export from plasma and dysregulation of zinc homeostasis in multiple tissues