A metalloproteomic analysis of interactions between plasma proteins and zinc: elevated fatty acid levels affect zinc distribution

Targeted removal of the FA2 site on human albumin prevents fatty acid-mediated inhibition of Zn2+ binding

Zinc is required for virtually all biological processes. In plasma, Zn2+ is predominantly transported by human serum albumin (HSA), which possesses two Zn2+-binding sites of differing affinities (sites A and B). Fatty acids (FAs) are also transported by HSA, with seven structurally characterized FA-binding sites (named FA1-FA7) known. FA binding inhibits Zn2+-HSA interactions, in a manner that can impact upon hemostasis and cellular zinc uptake, but the degree to which binding at specific FA sites contributes to this inhibition is unclear. Wild-type HSA and H9A, H67A, H247A, and Y150F/R257A/S287A (FA2-KO) mutant albumins were expressed in Pichia pastoris. Isothermal titration calorimetry studies revealed that the Zn2+-binding capacity at the high-affinity Zn2+ site (site A) was reduced in H67A and H247A mutants, with site B less affected. The H9A mutation decreased Zn2+ binding at the lower-affinity site, establishing His9 as a site B ligand. Zn2+ binding to HSA and H9A was compromised by palmitate, consistent with FA binding affecting site A. 13C-NMR experiments confirmed that the FA2-KO mutations prohibited FA binding at site FA2. Zn2+ binding to the FA2-KO mutant was unaffected by myristate, suggesting binding at FA2 is solely responsible for inhibition. Molecular dynamics studies identified the steric obstruction exerted by bound FA in site FA2, which impedes the conformational change from open (FA-loaded) to closed (FA-free) states, required for Zn2+ to bind at site A. The successful targeting of the FA2 site will aid functional studies exploring the interplay between circulating FA levels and plasma Zn2+ speciation in health and disease.

Zinc unbound concentration as an anchor to drive individualize repletion

BACKGROUND AND AIMS

Zinc (Zn) quantification is of particular interest in many clinical condition (e.g. inflammatory disease, critical care). Currently, Zn status is assessed by measuring plasma/serum concentration. This concentration corresponds to the sum of unbound Zn (Zn-Cu) and Zn highly bound to albumin (Zn-Cb).

METHODS

Using a pharmacokinetic approach to the interpretation of total Zn concentration (Zn-Ct), taking into account Zn-Cu and the influence of hypoalbuminemia on Zn-Cb, it is possible to improve the individualization of Zn repletion.

RESULTS

Therefore, during pregnancy and in certain inflammatory disease situations, repletion may not be necessary. However, as in critical care, it would be more appropriate to perform Zn-Cu assays to improve Zn repletion.

CONCLUSION

Coupled total and unbound Zn should be monitored in order to individualize Zn repletion.

Recent Advances in Metalloproteomics

Interactions between proteins and metal ions and their complexes are important in many areas of the life sciences, including physiology, medicine, and toxicology. Despite the involvement of essential elements in all major processes necessary for sustaining life, metalloproteomes remain ill-defined. This is not only owing to the complexity of metalloproteomes, but also to the non-covalent character of the complexes that most essential metals form, which complicates analysis. Similar issues may also be encountered for some toxic metals. The review discusses recently developed approaches and current challenges for the study of interactions involving entire (sub-)proteomes with such labile metal ions. In the second part, transition metals from the fourth and fifth periods are examined, most of which are xenobiotic and also tend to form more stable and/or inert complexes. A large research area in this respect concerns metallodrug-protein interactions. Particular attention is paid to separation approaches, as these need to be adapted to the reactivity of the metal under consideration.

Gd3+ Complexes for MRI Detection of Zn2+ in the Presence of Human Serum Albumin: Structure-Activity Relationships

Zn2+-responsive magnetic resonance imaging (MRI) contrast agents are typically composed of a Gd chelate conjugated to a Zn2+-binding moiety via a linker. They allow for Zn2+ detection in the presence of human serum albumin (HSA). In order to decipher the key parameters that drive their Zn2+-dependent MRI response, we designed a pyridine-based ligand, PyAmC2mDPA, and compared the properties of GdPyAmC2mDPA to those of analogue complexes with varying Gd core, Zn-binding moiety, or linker sizes. The stability constants determined by pH potentiometry showed the good selectivity of PyAmC2mDPA for Gd3+ (log KGd = 16.27) versus Zn2+ (log KZn = 13.58), proving that our modified Zn2+-binding DPA moiety prevents the formation of previously observed dimeric species. Paramagnetic relaxation enhancement measurements indicated at least three sites that are available for GdPyAmC2mDPA binding on HSA, as well as a 2-fold affinity increase when Zn2+ is present (KD = 170 μM versus KDZn = 60 μM). Fluorescence competition experiments provided evidence of the higher affinity for site II vs site I, as well as the importance of both the Zn-binding part and the Gd core in generating enhanced HSA affinity in the presence of Zn2+. Finally, an analysis of nuclear magnetic relaxation dispersion (NMRD) data suggested a significantly increased rigidity for the Zn2+-bound system, which is responsible for the Zn2+-dependent relaxivity response.

Characterizing metal-biomolecule interactions by mass spectrometry

Metal micronutrients are essential for life and exist in a delicate balance to maintain an organism's health. The labile nature of metal-biomolecule interactions clouds the understanding of metal binders and metal-mediated conformational changes that are influential to health and disease. Mass spectrometry (MS)-based methods and technologies have been developed to better understand metal micronutrient dynamics in the intra- and extracellular environment. In this review, we describe the challenges associated with studying labile metals in human biology and highlight MS-based methods for the discovery and study of metal-biomolecule interactions.

Analyzing cross-talk of EPO and EGF genes along with evaluating therapeutic potential of Cinnamomum verum in cigarette-smoke-induced lung pathophysiology in rat model

The integrity of the distal alveolar epithelium is crucial for lung regeneration following an injury. The present study aimed to evaluate the effect of Cinnamomum verum extract; cross-talk of epidermal growth factor (EGF) and erythropoietin (EPO) genes in a smoke-induced lung injury rat model. For experimentation (n = 27), albino rats were divided equally into three groups, i.e., negative control (NC), positive control (PC), and treatment group (TG). Cigarette smoke was exposed to PC and TG (4 CG/day). C. verum was given orally (350 mg/kg body weight) for 21 days. Decapitation (n = 3) was done on 14th, 18th, and 21st days, respectively. Analyses (hematology, biochemical, high performance liquid chromatography [HPLC], histology, and gene expression) were carried out and results were statistically analyzed by two-way analysis of variance. HPLC analysis of ethanolic extract of C. verum was done to identify the presence of phenolic constituents which showed high concentrations of quercetin and P-coumaric acid. Serum oxidative parameters such as total oxidant status, malondialdehyde, and hematological parameters such as red blood cells, hemoglobin, hematocrit, and white blood cells were significantly (p < .05) elevated in the PC group; however, these parameters were significantly (p < .05) improved in TG. While total antioxidant capacity and serum parameters such as total protein, albumin, and globulin were significantly (p < .05) reduced in the PC group but significantly improved (p < .05) in TG. Histological analysis revealed that smoke exposure resulted in a measurable increase in alveolar septal thickening while ethanolic extract of C. verum greatly ameliorated the histopathological changes in the lung alveoli. The gene expression analysis of EGF and EPO genes showed a significant upregulation (p < .05) of both genes in PC group while in TG, the level of both genes downregulated, in which lung damage was ameliorated due to cytoprotective effects of ethanolic extract of C. verum.

Thermodynamics-based rules of thumb to evaluate the interaction of chelators and kinetically-labile metal ions in blood serum and plasma

Metal ions play a very important role in nature and their homeostasis is crucial. A lot of metal-related chemical research activities are ongoing that concern metal-based drugs or tools, such as chelation therapy, metal- and metabolite sensors, metallo-drugs and prodrugs, PET and MRI imaging agents, etc. In most of these cases, the applied chelator/ligand (L) or metal-ligand complex (M-L) has at least to pass the blood plasma to reach the target. Hence it is exposed to several metal-binding proteins (mainly serum albumin and transferrin) and to all essential metal ions (zinc, copper, iron, etc.). This holds also for studies in cultured cells when fetal calf serum is used in the medium. There is a risk that the applied compound (L or M-L) in the serum is transformed into a different entity, due to trans-metallation and/or ligand exchange reactions. This depends on the thermodynamics and kinetics. For kinetically-labile complexes, the complex stability with all the ligands and all metal ions present in serum is decisive in evaluating the thermodynamic driving force towards a certain fate of the chelator or metal-ligand complex. To consider that, an integrative view is needed on the stability constants, by taking into account all the metal ions present and all the main proteins to which they are bound, as well as the non-occupied metal binding site in proteins. Only then, a realistic estimation of the complex stability, and hence its potential fate, can be done. This perspective aims to provide a simple approach to estimate the thermodynamic stability of labile metal-ligand complexes in a blood plasma/serum environment. It gives a guideline to obtain an estimation of the plasma and serum complex stability and metal selectivity starting from the chemical stability constants of metal-ligand complexes. Although of high importance, it does not focus on the more complex kinetic aspects of metal-transfer reactions. The perspective should help for a better design of such compounds, to perform test tube assays which are relevant to the conditions in the plasma/serum and to be aware of the importance of ternary complexes, kinetics and competition experiments.

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.

Speciomics as a concept involving chemical speciation and omics

The study of chemical speciation and the refinement and expansion of omics-based methods are both consolidated and highly active research fields. Although well established, such fields are extremely dynamic and are driven by the emergence of new strategies and improvements in instrumentation. In the case of omics-based studies, subareas including lipidomics, proteomics, metallomics, metabolomics and foodomics have emerged. Here, speciomics is being proposed as an "umbrella" term, that incorporates all of these subareas, to capture studies where the evaluation of chemical species is carried out using omics approaches. This paper contextualizes both speciomics and the speciome, and reviews omics applications used for species identification through examination of proteins, metalloproteins, metabolites, and nucleic acids. In addition, some implications from such studies and a perspective for future development of this area are provided. SIGNIFICANCE: The synergic effect between chemical speciation and omics is highlighted in this work, demonstrating an emerging area of research with a multitude of possibilities in terms of applications and further developments. This work not only defines and contextualizes speciomics and individual speciomes, but also demonstrates with some examples the great potential of this new interdisciplinary area of research.

Major trace elements and their binding proteins in the early phase of Covid-19 infection

Metal ions seem to play important roles in the pathogenesis of the novel coronavirus disease of 2019 (Covid-19) and are under investigation as potential prognostic markers and supplements in therapeutic procedures. The present study was aimed at assessing the relationship between the most abundant essential microelements (iron, zinc and copper) and their major binding proteins in the circulation in the early stage of infection. The concentration of zinc ions was measured to be higher in infected than in healthy persons, as well as ratios zinc/albumin and zinc/alpha-2-macroglobulin. Increased zinc levels could be attributed to cellular redistribution of zinc ions or to a use of zinc supplementation (zinc concentration was above the upper reference limit in one-third of infected individuals). Immunoblot analysis of protein molecular forms revealed that infected persons had greater amounts of proteinase-bound alpha-2-macroglobulin tetramer and albumin monomer than healthy individuals. The quantities of these forms were correlated with the concentration of zinc ions (r = 0.42 and 0.55, respectively) in healthy persons, but correlations were lost in infected individuals, most likely due to very high zinc concentrations in some participants which were not proportionally followed by changes in the distribution of protein species. Although we still have to wait for a firm confirmation of the involvement of zinc in beneficial defense mechanisms in patients with Covid-19, it seems that this ion may contribute to the existence of circulating protein forms which are the most optimal.

The role of oxidative stress markers in Indonesian chronic kidney disease patients: a cross sectional study

Background: Several aspects of chronic kidney disease (CKD) such as the incidence rate and mortality rate are concerning. Oxidative stress contributes to progression and mortality in patients with CKD; however, a specific correlation between several markers of oxidative stress and the estimated glomerular filtration rate (eGFR) and albumin-creatinine ratio (ACR) in the Indonesian population has not been sufficiently described yet. Methods: This study was an analytic observational study with a sample of 56 patients with CKD in Universitas Airlangga Hospital, Surabaya, Indonesia, from December 2019 – March 2020. The markers for oxidative stress investigated were urinary 8-hydroxy-2 deoxyguanosine (8-OHdG), serum symmetric dimethylarginine (SDMA) and asymmetric dimethylarginine (ADMA). The correlations between each variable of oxidative stress and CKD were analyzed using Pearson analysis. Results: There was a positive correlation between 8-OHdG and eGFR (p=0.00, r=0.51); however, there was a negative correlation between 8-OHdG and ACR (p=0.025, r=-0.30). SDMA and eGFR showed a negative correlation (p=0.00, r=-0.648), while SDMA and ACR showed a positive correlation (p=0.03, r=0.349). ADMA showed a negative correlation with eGFR (p=0.00, r=-0.476). There were significantly decreased 8-OHdG but increased ADMA and SDMA as the CKD stage progressed (p=0.001, p=0.00, and p = 0.00, respectively). Higher urine 8-OHdG was detected in patients without history of hemodialysis, whereas ADMA and SDMA showed higher value in patients with hemodialysis (p=0.00, p=0.00, and p=0.004, respectively), patients with history of diabetes mellitus (DM) had higher mean 8-OHdG (p 0.000) yet lower serum ADMA and SDMA (p=0.004 and p=0.003, respectively). Conclusions: In patients with CKD in Indonesia, the markers for oxidative stress 8-OHdG, SDMA, and ADMA are correlated with eGFR and ACR levels. There were also significant difference in 8-OHdG, SDMA, and ADMA levels among CKD stages, between dialysis vs non dialysis, and DM vs non DM patients.

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.

Fatty acids may influence insulin dynamics through modulation of albumin-Zn2+ interactions

Insulin is stored within the pancreas in an inactive Zn²⁺ -bound hexameric form prior to release. Similarly, clinical insulins contain Zn²⁺ and form multimeric complexes. Upon release from the pancreas or upon injection, insulin only becomes active once Zn²⁺ disengages from the complex. In plasma and other extracellular fluids, the majority of Zn²⁺ is bound to human serum albumin (HSA), which plays a vital role in controlling insulin pharmacodynamics by enabling removal of Zn²⁺ . The Zn²⁺ -binding properties of HSA are attenuated by non-esterified fatty acids (NEFAs) also transported by HSA. Elevated NEFA concentrations are associated with obesity and type 2 diabetes. Here we present the hypothesis that higher NEFA levels in obese and/or diabetic individuals may contribute to insulin resistance and affect therapeutic insulin dose-response profiles, through modulation of HSA/Zn²⁺ dynamics. We envisage this novel concept to have important implications for personalized treatments and management of diabetes-related conditions in the future.

The Interplay between Non-Esterified Fatty Acids and Plasma Zinc and Its Influence on Thrombotic Risk in Obesity and Type 2 Diabetes

Thrombosis is a major comorbidity of obesity and type-2 diabetes mellitus (T2DM). Despite the development of numerous effective treatments and preventative strategies to address thrombotic disease in such individuals, the incidence of thrombotic complications remains high. This suggests that not all the pathophysiological mechanisms underlying these events have been identified or targeted. Non-esterified fatty acids (NEFAs) are increasingly regarded as a nexus between obesity, insulin resistance, and vascular disease. Notably, plasma NEFA levels are consistently elevated in obesity and T2DM and may impact hemostasis in several ways. A potentially unrecognized route of NEFA-mediated thrombotic activity is their ability to disturb Zn²⁺ speciation in the plasma. Zn²⁺ is a potent regulator of coagulation and its availability in the plasma is monitored carefully through buffering by human serum albumin (HSA). The binding of long-chain NEFAs such as palmitate and stearate, however, trigger a conformational change in HSA that reduces its ability to bind Zn²⁺, thus increasing the ion’s availability to bind and activate coagulation proteins. NEFA-mediated perturbation of HSA-Zn²⁺ binding is thus predicted to contribute to the prothrombotic milieu in obesity and T2DM, representing a novel targetable disease mechanism in these disorders.

A novel 3D-printed centrifugal ultrafiltration method reveals in vivo glycation of human serum albumin decreases its binding affinity for zinc

Plasma proteins are covalently modified in vivo by the high-glucose conditions in the bloodstreams of people with diabetes, resulting in changes to both structure and function. Human Serum Albumin (HSA) functions as a carrier-protein in the bloodstream, binding various ligands and tightly regulating their bioavailability. HSA is known to react with glucose via the Maillard reaction, causing adverse effects on its ability to bind and deliver certain ligands, such as metals. Here, the binding between in vivo glycated HSA and zinc (Zn2+) was determined using a novel centrifugal ultrafiltration method that was developed using a 3D-printed device. This method is rapid (90 minutes), capable of high-throughput measurements (24 samples), low-cost (<$1.00 USD per device) and requires lower sample volumes (200 μL) compared to other binding techniques. This device was used to determine an equilibrium dissociation constant between Zn2+ and a commercially obtained normal HSA (nHSA) with a glycation level of 11.5% (Kd = 2.1 (±0.5) × 10-7 M). A glycated fraction of the nHSA sample was enriched (gHSA, 65.5%) and isolated using boronate-affinity chromatography, and found to have a 2.3-fold decrease in Zn2+ binding-affinity (Kd = 4.8 (±0.8) × 10-7 M) when compared to the nHSA sample. The level of glycation of HSA in control plasma (13.0% ± 0.8, n = 3 donors) and plasma from people with diabetes (26.9% ± 6.6, n = 5 donors) was assessed using mass spectrometry. Furthermore, HSA was isolated from plasma obtained in-house from a person with type 1 diabetes and found to have a glycation level of 24.1% and Kd = 3.3 (± 0.5) × 10-7 M for Zn2+, revealing a 1.5-fold decrease in binding affinity compared to nHSA. These findings suggest that increased levels of glycated HSA result in reduced binding to Zn2+, which may have implications in complications associated with diabetes.

Inhibition of an organophosphate-detoxifying bacterial phosphotriesterase by albumin and plasma thiol components

The phosphotriesterase of the bacterium Brevundimonas diminuta (BdPTE) is a naturally occurring enzyme that catalyzes the hydrolysis of organophosphate (OP) nerve agents as well as pesticides and offers a potential treatment of corresponding intoxications. While BdPTE mutants with improved catalytic efficiencies against several OPs have been described, unexpectedly, less efficient breakdown of an OP was observed upon application in an animal model compared with in vitro measurements. Here, we describe detailed inhibition studies with the high-activity BdPTE mutant 10-2C3(C59M/C227A) by human plasma components, indicating that this enzyme is inhibited by serum albumin. The inhibitory activity is mediated by depletion of crucial zinc ions from the BdPTE active site, either via the known high-affinity zinc binding site of albumin or via chemical complex formation with its free thiol side chain at position Cys34. Albumin pre-charged with zinc ions or carrying a chemically blocked Cys34 side chain showed significantly reduced inhibitory activity; in fact, the combination of both measures completely abolished BdPTE inhibition. Consequently, the available zinc ion concentration in blood plays an important role for BdPTE activity in vivo and should be taken into account for therapeutic development and application of a catalytic OP scavenger.

Toxic Metal Species and 'Endogenous' Metalloproteins at the Blood-Organ Interface: Analytical and Bioinorganic Aspects

Globally, human exposure to environmental pollutants causes an estimated 9 million deaths per year and it could also be implicated in the etiology of diseases that do not appear to have a genetic origin. Accordingly, there is a need to gain information about the biomolecular mechanisms that causally link exposure to inorganic environmental pollutants with distinct adverse health effects. Although the analysis of blood plasma and red blood cell (RBC) cytosol can provide important biochemical information about these mechanisms, the inherent complexity of these biological matrices can make this a difficult task. In this perspective, we will examine the use of metalloentities that are present in plasma and RBC cytosol as potential exposure biomarkers to assess human exposure to inorganic pollutants. Our primary objective is to explore the principal bioinorganic processes that contribute to increased or decreased metalloprotein concentrations in plasma and/or RBC cytosol. Furthermore, we will also identify metabolites which can form in the bloodstream and contain essential as well as toxic metals for use as exposure biomarkers. While the latter metal species represent useful biomarkers for short-term exposure, endogenous plasma metalloproteins represent indicators to assess the long-term exposure of an individual to inorganic pollutants. Based on these considerations, the quantification of metalloentities in blood plasma and/or RBC cytosol is identified as a feasible research avenue to better understand the adverse health effects that are associated with chronic exposure of various human populations to inorganic pollutants. Exposure to these pollutants will likely increase as a consequence of technological advances, including the fast-growing applications of metal-based engineering nanomaterials.

Mosquito metallomics reveal copper and iron as critical factors for Plasmodium infection

Iron and copper chelation restricts Plasmodium growth in vitro and in mammalian hosts. The parasite alters metal homeostasis in red blood cells to its favor, for example metabolizing hemoglobin to hemozoin. Metal interactions with the mosquito have not, however, been studied. Here, we describe the metallomes of Anopheles albimanus and Aedes aegypti throughout their life cycle and following a blood meal. Consistent with previous reports, we found evidence of maternal iron deposition in embryos of Ae. aegypti, but less so in An. albimanus. Sodium, potassium, iron, and copper are present at higher concentrations during larval developmental stages. Two An. albimanus phenotypes that differ in their susceptibility to Plasmodium berghei infection were studied. The susceptible white stripe (ws) phenotype was named after a dorsal white stripe apparent during larval stages 3, 4, and pupae. During larval stage 3, ws larvae accumulate more iron and copper than the resistant brown stripe (bs) phenotype counterparts. A similar increase in copper and iron accumulation was also observed in the susceptible ws, but not in the resistant bs phenotype following P. berghei infection. Feeding ws mosquitoes with extracellular iron and copper chelators before and after receiving Plasmodium-infected blood protected from infection and simultaneously affected follicular development in the case of iron chelation. Unexpectedly, the application of the iron chelator to the bs strain reverted resistance to infection. Besides a drop in iron, iron-chelated bs mosquitoes experienced a concomitant loss of copper. Thus, the effect of metal chelation on P. berghei infectivity was strain-specific.

Albumin-mediated alteration of plasma zinc speciation by fatty acids modulates blood clotting in type-2 diabetes

Zn2+ is an essential regulator of coagulation and is released from activated platelets. In plasma, the free Zn2+ concentration is fine-tuned through buffering by human serum albumin (HSA). Importantly, the ability of HSA to bind/buffer Zn2+ is compromised by co-transported non-esterified fatty acids (NEFAs). Given the role of Zn2+ in blood clot formation, we hypothesise that Zn2+ displacement from HSA by NEFAs in certain conditions (such as type 2 diabetes mellitus, T2DM) impacts on the cellular and protein arms of coagulation. To test this hypothesis, we assessed the extent to which increasing concentrations of a range of medium- and long-chain NEFAs reduced Zn2+-binding ability of HSA. Amongst the NEFAs tested, palmitate (16 : 0) and stearate (18 : 0) were the most effective at suppressing zinc-binding, whilst the mono-unsaturated palmitoleate (16 : 1c9) was markedly less effective. Assessment of platelet aggregation and fibrin clotting parameters in purified systems and in pooled plasma suggested that the HSA-mediated impact of the model NEFA myristate on zinc speciation intensified the effects of Zn2+ alone. The effects of elevated Zn2+ alone on fibrin clot density and fibre thickness in a purified protein system were mirrored in samples from T2DM patients, who have derranged NEFA metabolism. Crucially, T2DM individuals had increased total plasma NEFAs compared to controls, with the concentrations of key saturated (myristate, palmitate, stearate) and mono-unsaturated (oleate, cis-vaccenate) NEFAs positively correlating with clot density. Collectively, these data strongly support the concept that elevated NEFA levels contribute to altered coagulation in T2DM through dysregulation of plasma zinc speciation.

Integrated experimental/computational approaches to characterize the systems formed by vanadium with proteins and enzymes

An integrated instrumental/computational approach to characterize metallodrug–protein adducts at the molecular level is reviewed. A series of applications are described, focusing on potential vanadium drugs with a generalization to other metals.

Albumin and functionalized albumin nanoparticles: production strategies, characterization, and target indications

The inherent properties of albumin facilitate its effective use as a raw material to prepare a nanosized drug delivery vehicles. Because of the enhanced surface area, biocompatibility, and extended half-life of albumin nanoparticles, a number of drugs have been incorporated in albumin matrices in recent years. Furthermore, its ability to be conjugated to various receptor ligands makes albumin an ideal candidate for the increased delivery of drugs to specific sites. The present review provides an in-depth discussion of production strategies for the preparation of albumin and conjugated albumin nanoparticles and for the targeting of these formulations to specific organs and cancer cells. This review also provides insights into drug loading, release patterns, and cytotoxicity of various drug-loaded albumin nanoparticles.

Zinc Deficiency-An Independent Risk Factor in the Pathogenesis of Haemorrhagic Stroke?

Zinc is an essential trace element for human health and plays a fundamental role in metabolic, immunological and many other biological processes. The effects of zinc are based on the intra- and extracellular regulatory function of the zinc ion (Zn2+) and its interactions with proteins. The regulation of cellular zinc homeostasis takes place via a complex network of metal transporters and buffering systems that react to changes in the availability of zinc in nutrition, chronic diseases, infections and many other processes. Zinc deficiency is associated with impairment of numerous metabolic processes, reduced resistance to infections due to impaired immune functions, changes in skin and its appendages and disorders of wound healing and haemostasis. While ischemic heart attacks (myocardial infarction) occur more frequently with meat-based normal diets, haemorrhagic strokes are more frequently observed with vegetarian/vegan diets. The causes are discussed as deficiencies of various micronutrients, such as vitamin B12, vitamin D, various amino acids and also zinc. In the present review, after a description of the functions of zinc and its resorption, a discussion of daily food intake will follow, with a special focus on the importance of food composition and preparation for the zinc balance. The close interrelationships between proteins, especially albumin and zinc will be discussed. Finally, the possible causes and consequences of a zinc deficiency on the blood vessels and blood coagulation are considered.

Zinc as a Therapeutic Agent in Bone Regeneration

Zinc is an essential mineral that is required for normal skeletal growth and bone homeostasis. Furthermore, zinc appears to be able to promote bone regeneration. However, the cellular and molecular pathways through which zinc promotes bone growth, homeostasis, and regeneration are poorly understood. Zinc can positively affect chondrocyte and osteoblast functions, while inhibiting osteoclast activity, consistent with a beneficial role for zinc in bone homeostasis and regeneration. Based on the effects of zinc on skeletal cell populations and the role of zinc in skeletal growth, therapeutic approaches using zinc to improve bone regeneration are being developed. This review focuses on the role of zinc in bone growth, homeostasis, and regeneration while providing an overview of the existing studies that use zinc as a bone regeneration therapeutic.

Effect of albumin on the transformation of dinitrosyl iron complexes with thiourea ligands

BSA binds the Fe(NO)₂⁺ fragment of DNIC and multiple molecules of [Fe(SC(NH₂)₂)₂(NO)₂]⁺ that prolongs NO donation by this DNIC.

Coagulatory Defects in Type-1 and Type-2 Diabetes

Diabetes (both type-1 and type-2) affects millions of individuals worldwide. A major cause of death for individuals with diabetes is cardiovascular diseases, in part since both types of diabetes lead to physiological changes that affect haemostasis. Those changes include altered concentrations of coagulatory proteins, hyper-activation of platelets, changes in metal ion homeostasis, alterations in lipid metabolism (leading to lipotoxicity in the heart and atherosclerosis), the presence of pro-coagulatory microparticles and endothelial dysfunction. In this review, we explore the different mechanisms by which diabetes leads to an increased risk of developing coagulatory disorders and how this differs between type-1 and type-2 diabetes.