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PurposeSerum magnesium is the most frequently used laboratory test for evaluating clinical magnesium status. Hypomagnesemia (low magnesium status), which is associated with many chronic diseases, is diagnosed using the serum magnesium reference range. Currently, no international consensus for a magnesemia normal range exists. Two independent groups designated 0.85 mmol/L (2.07 mg/dL; 1.7 mEq/L) as the low cut-off point defining hypomagnesemia. MaGNet discussions revealed differences in serum magnesium reference ranges used by members’ hospitals and laboratories, presenting an urgent need for standardization.MethodsWe gathered and compared serum magnesium reference range values from our institutions, hospitals, and colleagues worldwide.ResultsSerum magnesium levels designating “hypomagnesemia” differ widely. Of 43 collected values, only 2 met 0.85 mmol/L as the low cut-off point to define hypomagnesemia. The remainder had lower cut-off values, which may underestimate hypomagnesemia diagnosis in hospital, clinical, and research assessments. Current serum magnesium reference ranges stem from “normal” populations, which unknowingly include persons with chronic latent magnesium deficit (CLMD). Serum magnesium levels of patients with CLMD fall within widely used “normal” ranges, but their magnesium status is too low for long-term health. The lower serum magnesium reference (0.85 mmol/L) proposed specifically prevents the inclusion of patients with CLMD.ConclusionsWidely varying serum magnesium reference ranges render our use of this important medical tool imprecise, minimizing impacts of low magnesium status or hypomagnesemia as a marker of disease risk. To appropriately diagnose, increase awareness of, and manage magnesium status, it is critical to standardize lower reference values for serum magnesium at 0.85 mmol/L (2.07 mg/dL; 1.7 mEq/L).

BackgroundDespite inadequate supply and potential contamination risk, human plasma has remained the only source for human serum albumin (pHSA) intravenous administration since the 1940s.ObjectiveWe sought to establish the safety and efficacy of OsrHSA, a recombinant HSA from bioengineered Oryza sativa (rice).DesignIn this multicentre, randomised, double-blind and positive-controlled study, patients with decompensated liver cirrhosis and serum albumin ≤30 g/L were recruited from 22 centres in China. The patients were randomly assigned to OsrHSA or pHSA (4:1) to once-daily intravenous injection (10 g or 20 g) until their serum albumin level reached 35 g/L, for a maximum of 2 weeks, with 2 weeks of follow-up. The primary outcome was the proportion of patients to reach a serum albumin level of 35 g/L (non-inferiority margin <−0.20). Outcomes were evaluated in patients who received the study drug and had at least one post-baseline serum albumin value (full analysis set, FAS). Safety was evaluated in all patients who received the study drug.ResultsBetween 22 March 2021 and 2 June 2022, 220 patients received OsrHSA (n=175) or pHSA (n=45). 216 patients were included in the FAS (OsrHSA, n=171; pHSA, n=45). Primary outcome of OsrHSA (130/171, 76%) was non-inferior to pHSA (34/45, 75.6%) (difference=0.5%; lower limit of 97.5% CI=−0.119). There was no significant difference between all secondary outcomes of OsrHSA and pHSA. There were no drug-related serious adverse events.ConclusionsRice-derived HSA is non-inferior to plasma-derived HSA in efficacy and safety. This finding should be confirmed in phase 3 trial.Trial registration number NCT04835480.

Serum albumin (SA) plays a fundamental role in the transport of metabolites and endogenous ligands. Additionally, animal albumins are potent allergens. Heterologous expression of SAs is challenging due to their complex structure. In this study, we describe a simple method for enhanced production of soluble and functional recombinant feline (rFel d 2) and canine (rCan f 3) albumins in the standard strain BL21 (DE3). To achieve this, the 18-amino acid signal peptide was removed from the N-terminus of each albumin. To improve expression, folding, and solubility of recombinant proteins, we tested an extended panel of fusion proteins. Among them, MBP (maltose-binding protein), TF (trigger factor), and NusA ( transcription termination factor) allowed the production of soluble fusion forms of rFel d 2 and rCan f 3. To confirm the structural integrity of the products, we analyzed the IgE-binding characteristics of recombinant versus native albumins. rFel d 2 and rCan f 3 fused with TF, MBP, and NusA bound albumin-specific immunoglobulin E (in 26/33, 29/33, 31/33, and 27/29, 26/29, 27/29 cases, respectively, comparable to native Fel d 2 and Can f 3. Thus, removal of the signal peptide combined with fusion partners enables expression of Fel d 2 and Can f 3 in with preserved antigenic properties.

The formation of neutrophil extracellular traps (NETs) is an immune defense mechanism of neutrophilic granulocytes. Moreover, it is also involved in the pathogenesis of autoimmune, inflammatory, and neoplastic diseases. For that reason, the process of NET formation (NETosis) is subject of intense ongoing research. approaches to quantify NET formation are commonly used and involve neutrophil stimulation with various activators such as phorbol 12-myristate 13-acetate (PMA), lipopolysaccharides (LPS), or calcium ionophores (CaI). However, the experimental conditions of these experiments, particularly the media and media supplements employed by different research groups, vary considerably, rendering comparisons of results difficult. Here, we present the first standardized investigation of the influence of different media supplements on NET formation . The addition of heat-inactivated (hi) fetal calf serum (FCS), 0.5% human serum albumin (HSA), or 0.5% bovine serum albumin (BSA) efficiently prevented NET formation of human neutrophils following stimulation with LPS and CaI, but not after stimulation with PMA. Thus, serum components such as HSA, BSA and hiFCS (at concentrations typically found in the literature) inhibit NET formation to different degrees, depending on the NETosis inducer used. In contrast, in murine neutrophils, NETosis was inhibited by FCS and BSA, regardless of the inducer employed. This shows that mouse and human neutrophils have different susceptibilities toward the inhibition of NETosis by albumin or serum components. Furthermore, we provide experimental evidence that albumin inhibits NETosis by scavenging activators such as LPS. We also put our results into the context of media supplements most commonly used in NET research. In experiments with human neutrophils, either FCS (0.5-10%), heat-inactivated (hiFCS, 0.1-10%) or human serum albumin (HSA, 0.05-2%) was commonly added to the medium. For murine neutrophils, serum-free medium was used in most cases for stimulation with LPS and CaI, reflecting the different sensitivities of human and murine neutrophils to media supplements. Thus, the choice of media supplements greatly determines the outcome of experiments on NET-formation, which must be taken into account in NETosis research.

Cell surface glycans form various “glycan patterns” consisting of different types of glycan molecules, thus enabling strong and selective cell-to-cell recognition. We previously conjugated different N -glycans to human serum albumin to construct glycoalbumins mimicking natural glycan patterns that could selectively recognize target cells or control excretion pathways in mice. Here, we develop an innovative glycoalbumin capable of undergoing transformation and remodeling of its glycan pattern in vivo, which induces its translocation from the initial target to a second one. Replacing α(2,3)-sialylated N -glycans on glycoalbumin with galactosylated glycans induces the translocation of the glycoalbumin from blood or tumors to the intestine in mice. Such “in vivo glycan pattern remodeling” strategy can be used as a drug delivery system to promote excretion of a drug or medical radionuclide from the tumor after treatment, thereby preventing prolonged exposure leading to adverse effects. Alternatively, this study provides a potential strategy for using a single glycoalbumin for the simultaneous treatment of multiple diseases in a patient. Cell surface glycans form glycan patterns consisting of different types of glycan molecules, thus enabling strong and selective cell-to-cell recognition. In this study, the authors report a method based on the manipulation of glycan patterns to translocate a glycosylated albumin from blood or tumor to intestine by remodeling the α(2,3)-sialylated glycan pattern into a galactosylated pattern on albumin via a bioorthogonal chemical reaction.

Serum levels of early-glycated albumin are significantly increased in patients with diabetes mellitus and may play a role in worsening inflammatory status and sustaining diabetes-related complications. To investigate possible pathological recognition involving early-glycated albumin and the receptor for advanced glycation end products (RAGE), an early-glycated human serum albumin (HSAgly), with a glycation pattern representative of the glycated HSA form abundant in diabetic patients, and the recombinant human RAGE ectodomain (VC1) were used. Biorecognition between the two interactants was investigated by combining surface plasmon resonance (SPR) analysis and affinity chromatography coupled with mass spectrometry (affinity-MS) for peptide extraction and identification. SPR analysis proved early-glycated albumin could interact with the RAGE ectodomain with a steady-state affinity constant of 6.05 ± 0.96 × 10−7 M. Such interaction was shown to be specific, as confirmed by a displacement assay with chondroitin sulfate, a known RAGE binder. Affinity-MS studies were performed to map the surface area involved in the recognition. These studies highlighted that a region surrounding Lys525 and part of subdomain IA were involved in VC1 recognition. Finally, an in silico analysis highlighted (i) a key role for glycation at Lys525 (the most commonly glycated residue in HSA in diabetic patients) through a triggering mechanism similar to that previously observed for AGEs or advanced lipoxidation end products and (ii) a stabilizing role for subdomain IA. Albeit a moderate affinity for complex formation, the high plasma levels of early-glycated albumin and high percentage of glycation at Lys525 in diabetic patients make this interaction of possible pathological relevance.

Gold nanoparticles (AuNPs) are potentially applicable in drug/nucleic acid delivery systems. Low toxicity, high stability, and bioavailability are crucial for the therapeutic use of AuNPs and they are mainly determined by their interactions with proteins and lipids on their route to the target cells. In this work, we investigated the interaction of two pegylated gold nanoparticles, AuNP14a and AuNP14b, with human serum proteins albumin (HSA) and transferrin (Tf) as well as dimyristoyl-phosphatidylcholine (DMPC) liposomes, which can be a representative of biomembranes. We showed that AuNP14a/b interacted with HSA and Tf changing their electrical, thermodynamic, and structural properties as evidenced by dynamic light scattering, zeta potential, transmission electron microscopy, circular dichroism, fluorescence quenching, and isothermal titration calorimetry. These nanoparticles penetrated the DMPC membrane suggesting their ability to reach a target inside the cell. In most of the effects, AuNP14b was more effective than AuNP14a, which might result from its more positive charge. Further studies are needed to evaluate whether the interaction of AuNP14a/b with HSA and Tf is safe for the cell/organism and whether they may safely penetrate natural membranes.

In this study, temperature-responsive polymer-protein conjugate was synthesized using a “grafting from” concept by introducing a chain transfer agent (CTA) into bovine serum albumin (BSA). The BSA-CTA was used as a starting point for poly(N-isopropylacrylamide) (PNIPAAm) through reversible addition-fragmentation chain transfer polymerization. The research investigations suggest that the thermally responsive behavior of PNIPAAm was controlled by the monomer ratio to CTA, as well as the amount of CTA introduced to BSA. The study further synthesized the human serum albumin (HSA)-PNIPAAm conjugate, taking the advantage that HSA can specifically adsorb indoxyl sulfate (IS) as a uremic toxin. The HSA-PNIPAAm conjugate could capture IS and decreased the concentration by about 40% by thermal precipitation. It was also revealed that the protein activity was not impaired by the conjugation with PNIPAAm. The proposed strategy is promising in not only removal of uremic toxins but also enrichment of biomarkers for early diagnostic applications.

In animal models of ischaemic stroke, 25% albumin reduced brain infarction and improved neurobehavioural outcome. In a pilot clinical trial, albumin doses as high as 2 g/kg were safely tolerated. We aimed to assess whether albumin given within 5 h of the onset of acute ischaemic stroke increased the proportion of patients with a favourable outcome. We did a randomised, double-blind, parallel-group, phase 3, placebo-controlled trial between Feb 27, 2009, and Sept 10, 2012, at 69 sites in the USA, 13 sites in Canada, two sites in Finland, and five sites in Israel. Patients aged 18–83 years with ischaemic (ie, non-haemorrhagic) stroke with a baseline National Institutes of Health stroke scale (NIHSS) score of 6 or more who could be treated within 5 h of onset were randomly assigned (1:1), via a central web-based randomisation process with a biased coin minimisation approach, to receive 25% albumin (2 g [8 mL] per kg; maximum dose 750 mL) or the equivalent volume of isotonic saline. All study personnel and participants were masked to the identity of the study drug. The primary endpoint was favourable outcome, defined as either a modified Rankin scale score of 0 or 1, or an NIHSS score of 0 or 1, or both, at 90 days. Analysis was by intention to treat. Thrombolytic therapies were permitted. This trial is registered with ClinicalTrials.gov, number NCT00235495. 422 participants were randomly assigned to receive albumin and 419 to receive saline. On Sept 12, 2012, the trial was stopped early for futility (n=841). The primary outcome did not differ between patients in the albumin group and those in the saline group (186 [44%] vs 185 [44%]; risk ratio 0·96, 95% CI 0·84–1·10, adjusted for baseline NIHSS score and thrombolysis stratum). Mild-to-moderate pulmonary oedema was more common in patients given albumin than in those given saline (54 [13%] of 412 vs 5 [1%] of 412 patients); symptomatic intracranial haemorrhage within 24 h was also more common in patients in the albumin group than in the placebo group (17 [4%] of 415 vs 7 [2%] of 414 patients). Although the rate of favourable outcome in patients given albumin remained consistent at 44–45% over the course of the trial, the cumulative rate of favourable outcome in patients given saline rose steadily from 31% to 44%. Our findings show no clinical benefit of 25% albumin in patients with ischaemic stroke; however, they should not discourage further efforts to identify effective strategies to protect the ischaemic brain, especially because of preclinical literature showing convincing proof-of-principle for the possibility of this outcome. National Institute of Neurological Disorders and Stroke, US National Institutes of Health; and Baxter Healthcare Corporation.

Type 1 diabetes remains an important health-care problem, with no disease-modifying therapies available in people with recent-onset, clinical type 1 diabetes. Adaptive trial designs, allowing faster evaluation of treatment modalities, remain underexplored in this stage of the disease. We aimed to identify the minimum effective dose of antithymocyte globulin (ATG) in people aged 5–25 years with recent-onset, clinical type 1 diabetes. MELD-ATG was a phase 2, double-blind, randomised, placebo-controlled, multi-arm, adaptive dose-ranging, parallel-cohort trial done in 14 accredited trial centres in eight countries (the UK, Denmark, Germany, Finland, Italy, Belgium, Austria, and Slovenia). Participants aged 5–25 years, diagnosed with clinical, stage 3 type 1 diabetes 3–9 weeks before treatment, with random C-peptide concentrations 0·2 nmol/L or more and at least one diabetes-related autoantibody (GADA, IA-2A, or ZnT8) were randomly assigned by a web-based randomisation system into seven consecutive cohorts receiving placebo, 2·5 mg/kg ATG, 1·5 mg/kg ATG, 0·5 mg/kg ATG, or 0·1 mg/kg ATG. Participants in cohort 1 were randomly assigned 1:1:1:1:1, participants in cohorts 2 and 3 were randomly assigned 1:1:1:1, and participants in cohorts 4–7 were randomly assigned 1:1:1. All cohorts included one placebo group and one 2·5 mg/kg ATG group. The other groups were assigned to ATG doses that were determined based on accruing data and the decision of the dose determining committee. The trial cohorts were stratified by age group (5–9 years, 10–17 years, and 18–25 years) with block sizes varying by cohort. Concealment lists, outlining the treatment allocation, were only available for the pharmacists; participants and study teams were masked to treatment allocation. ATG was administered by an intravenous infusion over 2 consecutive days. The primary outcome was the area under the curve (AUC) of the stimulated C-peptide concentration during a 2-h mixed-meal tolerance test at 12 months measured as ln(AUC C-peptide + 1). Conditional on finding a statistically significant difference at p<0·05 for 2·5 mg/kg ATG versus placebo, the minimum effective dose of ATG was determined. All randomly assigned participants were included in the primary analysis. All participants who received the study drug were included in the safety analysis. The trial was registered at ClinicalTrials.gov (NCT04509791) and is completed. Between Nov 24, 2020, and Dec 13, 2023, 152 people were recruited and screened, 117 of whom were randomly assigned (placebo n=31, 0·1 mg/kg ATG n=6, 0·5 mg/kg ATG n=35, 1·5 mg/kg ATG n=12, and 2·5 mg/kg n=33). 54 (46%) of 117 participants were male and 63 (54%) were female. Participants were mainly European. The 0·1 mg/kg dose and the 1·5 mg/kg dose were progressively dropped from the study. At 12 months, the mean ln(AUC C-peptide + 1) was 0·411 nmol/L per min (SD 0·032) in the placebo group and 0·535 nmol/L per min (0·032) in the 2·5 mg/kg ATG group. The mean difference in the ln(AUC C-peptide + 1) between 2·5 mg/kg ATG and placebo was 0·124 nmol/L per min (95% CI 0·043–0·205; p=0·0028). At 12 months, the mean ln(AUC C-peptide + 1) in the 0·5 mg/kg ATG group, the remaining middle dose, was 0·513 nmol/L per min (SD 0·032), with a mean baseline-adjusted difference from placebo of 0·102 nmol/L per min (95% CI 0·021–0·183; p=0·014). Cytokine release syndrome occurred in 11 (33%) of 33 participants in the 2·5 mg/kg ATG group, eight (24%) of 34 in the 0·5mg/kg ATG group, and no participants in the placebo group. Serum sickness occurred in 27 (82%) participants in the 2·5 mg/kg ATG group, 11 (32%) in the 0·5 mg/kg ATG group, and no participants in the placebo group. There were no deaths related to adverse events. In young people with recent-onset, clinical type 1 diabetes, 2·5 mg/kg and 0·5 mg/kg ATG reduced loss of β-cell function, showing the potential of an affordable, repurposed agent, ATG, in a low and safe dose, as a disease-modifying agent in this population. The European Union's Innovative Medicines Initiative 2 Joint Undertaking INNODIA.