Human Albumin Levels Research Articles

Relationships between human serum albumin levels and septic shock, in-hospital, and out-of-hospital mortality in elderly patients with pneumonia in different BMI ranges

ObjectiveThis retrospective cohort identified the association of human serum albumin (HSA) with adverse outcomes (septic shock, in-hospital and out-of-hospital mortality) in elderly hospitalized patients who have community-acquired pneumonia (CAP) and specific body mass index (BMI).Materials and methodsThis research included hospitalized CAP individuals (≥ 60 years) and was conducted at a teaching hospital in western China. All the patients were categorized into three populations based on two BMI cutoff values (18.5 kg/m2 and 24 kg/m2). The data was acquired from medical records, local government mortality databases, and telephone interviews. Binomial logistic regression analysis was used to explore the associations between low HSA and septic shock and in-hospital mortality, and Cox regression analysis was used to explore the association between low HSA and out-of-hospital mortality.ResultsA total of 627 patients were included in the analysis of in-hospital death and septic shock, and 431 patients were included in the analysis of out-of-hospital death. The study showed that 120 elderly patients with CAP (19.14%) died in the hospital, while 141 patients (32.71%) died out of the hospital, and 93 patients (14.83%) developed septic shock. No differences in in-hospital and out-of-hospital mortality were observed for BMI values < 18.5 kg/m2 or BMI ≥ 24 kg/m2, regardless of whether HSA was ≥ 40 g/l or < 40 g/l. When 18.5 kg/m2 ≤ BMI < 24 kg/m2, patients with HSA < 40 g/l had both higher in-hospital and out-of-hospital mortality compared with those with HSA ≥ 40 g/l (in-hospital death: 26.13% vs. 11.46%, p < 0.001; out-of-hospital death: 46.15% vs. 19.17%, p < 0.001). No significant differences were observed in the incidence of septic shock between patients with HSA < 40 g/l and those with HSA ≥ 40 g/l either in the overall population or when the BMI values were divided according to the cutoff values of 18.5 kg/m2 and 24 kg/m2. After further logistic regression analysis and adjustment for potential confounders, the results showed that when 18.5 kg/m2 ≤ BMI < 24 kg/m2, elderly CAP patients with HSA < 40 g/l had a higher risk of in-hospital and out-of-hospital mortality compared with those with HSA ≥ 40 g/l (in-hospital death: HR = 1.964, 95%CI = 1.08–3.573; out-of-hospital death: HR = 2.841, 95%CI = 1.745–4.627).ConclusionsHSA levels can predict the risk of in-hospital and out-of-hospital mortality in elderly patients with CAP and normal BMI values. However, HSA cannot predict the risk of septic shock in elderly patients hospitalized with CAP, irrespective of their BMI classification.

Interferon alpha induces a stronger antiviral effect than interferon lambda in HBV/HDV infected humanized mice

Recent studies indicate that treatment of chronic hepatitis D virus (HDV) with either pegylated interferon (IFN)λ or pegylated IFNα monotherapy leads to a dramatic decline in HDV RNA. Herein, we investigated the innate antiviral efficacy of IFNλ and IFNα in humanized mice that lack an adaptive immune response. Humanized mice were either co-infected with hepatitis B virus (HBV) and HDV simultaneously, or HDV infection was performed subsequent to HBV infection (i.e., superinfected). After steady viral replication was achieved, mice received either IFNλ (n = 6) or IFNα (n = 7) for 12 (or 13) weeks. Pretreatment median levels of serum HBV DNA (8.8 [IQR:0.2] log IU/ml), HDV RNA (9.8 [0.5] log IU/ml), HBsAg (4.0 [0.4] log IU/ml) and human albumin, hAlb (6.9 [0.1] log ng/mL) were similar between mice treated with IFNα or IFNλ and between those coinfected versus superinfected. Compared to mice treated with IFNλ, mice treated with IFNα had a significantly greater decline in HBV, HDV, and HBsAg levels. In conclusion, IFNα induces stronger inhibition of HBV and HDV than IFNλ in humanized mice that lack an adaptive immune response. Further studies are needed to assess the respective role of the combined innate-and adaptive-immune systems in the treatment of HBV and HDV with IFNα and IFNλ.

Precise determination of human serum albumin levels in blood serum by a D-π-A based near-infrared fluorescent probe via TICT mechanism

Human serum albumin (HSA) levels in the body are crucial for the accurate diagnosis of various health issues, necessitating continuous monitoring and novel detection methods. This study focused on the development and synthesis of two novel D-π-A small molecule near-infrared fluorescent probes, PTPA-B and CPTPA-B. The probes demonstrated selective detection of HSA with a rapid response time of 1 min and high sensitivity, featuring limits of detection (LOD) of 0.102 μM and 1.702 μM. Under physiological conditions, the intrinsic fluorescence of these probes is minimal due to intramolecular charge transfer (TICT). Upon entering the hydrophobic cavity of HSA, the probes exhibit red fluorescence by inhibiting the TICT process. Additionally, the probes exhibited enhanced biocompatibility in living cells and enabled fluorescence imaging of L-02 live cells. Therefore, the PTPA-B fluorescent probe serves as an effective tool for serum detection, revealing its potential applications in live cell imaging and precise clinical diagnosis.

Engineering Tb(III)-functionalized HOF fluorescence sensing system for intelligent visual detection of two biomarkers of hepatocellular carcinoma

Abnormal levels of bilirubin and human serum albumin are precursors to hepatocellular carcinoma and many fatal diseases. Establishing a portable, highly sensitive and intuitive dual biomarker detection method for bilirubin and human serum albumin is important to protect human health. Combined with the excellent photoluminescence properties of lanthanide functionalized hydrogen bond organic framework, a novel ratiometric fluorescence intelligent sensing system was engineered with the outstanding features of large Stokes shifts, high luminous stability and the self-calibration effect of dual emission centers in this paper. With the advantage of high sensitivity, strong stability and strong anti-interference, the simultaneous detection of dual biomarkers was realized successfully. The developed fluorescence sensing system had a wide detection range of bilirubin and human serum albumin (13.5 nM ∼ 30.0 μM and 448 nM ∼ 15.0 μM), low detection limits (7.20 nM and 15.6 nM). Furthermore, the developed sensing system realized the smartphone-assisted fluorescence visual detection of bilirubin and human serum albumin in serum and urine successfully with the detection limit of 85 nM and 163 nM, providing a promising detection strategy for the early diagnosis of hepatocellular carcinoma.

Lipid nanoparticle-encapsulated DOCK11-siRNA efficiently reduces hepatitis B virus cccDNA level in infected mice

The hepatitis B virus (HBV) infects many people worldwide. As HBV infection frequently leads to liver fibrosis and carcinogenesis, developing anti-HBV therapeutic drugs is urgent. Therapeutic drugs for preventing covalently closed circular DNA (cccDNA) production, which can eliminate HBV infection, are unavailable. The host factor dedicator of cytokinesis 11 (DOCK11) is involved in the synthesis and maintenance of HBV cccDNA in vitro. However, the effectiveness of DOCK11 as a target for the in vivo elimination of HBV cccDNA remains unclear. In this study, we assessed whether DOCK11 inhibitors suppressed HBV cccDNA production in mouse models of HBV infection. The tocopherol-conjugate hetero gapmer, a DNA/RNA duplex of gapmer/complementary RNA targeting the DOCK11 sequence, partially reduced the expression of DOCK11 but not that of HBV cccDNA, in the livers of HBV-infected human hepatocyte chimeric mice, along with weight loss and decreased serum human albumin levels. Lipid nanoparticle-encapsulated chemically modified siRNAs specific for DOCK11 suppressed DOCK11 expression and decreased HBV cccDNA levels without adverse effects in the mice. Therefore, nucleic acid-based drugs targeting DOCK11 in hepatocytes are potentially effective anti-HBV therapeutics, which can reduce HBV cccDNA levels in vivo.

An ultrasensitive, selective pseudoesterase-activated fluorescent probe for monitoring acetylation modification, configuration transformation and biological levels of human serum albumin

Quantitative assays and the structural monitoring of human serum albumin (HSA) are essential for disease diagnosis, drug development, and physiological studies. Commonly used methods for quantifying HSA are based on the dye-HSA binding mechanism, which involves determining the absorption or fluorescence signal when the dye binds non-covalently to HSA. However, these methods generally suffer from poor selectivity and susceptibility to interference from co-existing species. Herein, an ultrasensitive and selective fluorescent probe, 2-(2-morpholinoethyl)-1,3-dioxo-2,3-dihydro-1 H-benzo[de]isoquinolin-6-yl cyclopropanecarboxylate (MDDH), was designed based on the pseudoesterase activity of HSA and used to monitor the acetylation modification, configuration transformation, and biological levels of HSA. Upon catalysis by HSA, the cyclopropanecarbonyl ester bound to MDDH undergoes hydrolysis, yielding a strong fluorescent signal. In contrast to conventional HSA-binding dyes, MDDH demonstrates superior sensitivity (with a 302-fold fluorescence enhancement), high selectivity for distinguishing between HSA and bovine serum albumin, and strong anti-interference against various coexisting species. By sensing HSA pseudoesterase activity, MDDH allows for the sensitive monitoring of structural changes in HSA, including aspirin-induced acetylation, guanidine hydrochloride-induced defolding and trypsin-induced cleavage. Moreover, MDDH exhibits strong stability, low cytotoxicity and good cell membrane permeability. It is suitable for the quantitative determination of HSA in the serum and urine, as well as for the fluorescence imaging of HSA in cells. Our work provides an efficient tool for monitoring the acetylation modifications, configuration changes, and biological content of HSA.

Molecularly imprinted electrochemiluminescence sensor based on a novel luminol derivative for detection of human serum albumin via click reaction.

Anovel luminol derivative of N-(1,4-dioxo-1,2,3,4-tetrahydrophthalazin-5-yl)acrylamide (DTA) with excellent luminescence efficiency was designed and synthesized. Furthermore, a molecularly imprinted electrochemiluminescence sensor (MIECLS) was fabricated to detect ultratrace levels of human serum albumin (HSA) with high sensitivity and selectivity via a click reaction. The molecularly imprinted polymers (MIPs) were formed on the electrode surface via electropolymerization with HSA as a template molecule and catechol as a monomer. In the detection process, the -SH group of HSA on the electrode and the C = C bond of acryloyl group in DTA formed a new C-S bond via the Michael addition reaction to construct the MIECLS. The higher the concentration of HSA, the greater electrochemiluminescence (ECL) intensity measured. Taking advantage of MIECLS for ECL detection (scanning potential, - 0.4 to 0.5V), there was a good linear relationship between ECL intensity and the logarithm of HSA concentration in the range 5 × 10-9 to 1 × 10-13mgmL-1. The limit of detection (LOD) of the sensor was 1.05 × 10-15mgmL-1. The sensor exhibited outstanding selectivity and stability. Thesensor was applied to detect HSA in human serum with good recoveries of 97.7-105.2%. Theconcentration of HSA was detected by electrochemical method using the gating effect of MIP.

The correlation between biochemical indicators in COVID-19 patients with and without Diabetes Mellitus in Basra, Iraq.

The coronavirus disease (COVID-19) is an infectious viral illness that leads to the development of acute respiratory syndrome. It exhibits a high level of contagiousness. The aforementioned virus is accountable for an incidence of pneumonia that transpired in early December 2019 in Wuhan, situated in the People's Republic of China. The global pandemic declaration on March 11, 2020, marked a significant turning point in the world's demography, as the virus had tragically claimed the lives of over 5.3 million individuals worldwide. The emergence of the Coronavirus (COVID-19) pandemic has presented an unparalleled catastrophe, resulting in the loss of many lives via several channels including social, psychological, physical, and economic dimensions. The danger associated with the virus originates from its heightened transmissibility and extensive mutational variability, as well as its impact on several bodily systems including the circulatory, neurological, renal, hepatic, nervous, and endocrine systems. The pathogenesis of Coronavirus disease 2019 (COVID-19) is intricate, and its clinical presentation is diverse, exhibiting various imaging findings that vary based on the severity of the illness and its progression through time. A general statistical comparison was made for the biochemical markers in the patients infected with only Coronavirus and patients infected with Coronavirus and complications of diabetes mellitus compared to the control group according to gender, in order to monitor the role of different biomarkers in causing a disease, with an evaluation of the difference in their levels, and the study aimed to investigate biomarkers and study the relationship between these biomarkers for COVID-19 patients with and without Diabetes Mellitus, to provide a dynamic approach to understanding the disease to diagnosis and follow-up, so as to improve the development of patients' treatment. The study performed a representative sample of (238) participants between the ages (25-80) year, of whom (81) were in a healthy control group, (78) were infected only with Coronavirus, (79) were infected with Coronavirus and had complications of diabetes mellitus, who visited Al-Basra Teaching Hospital and Allmwanei Hospital in Al-Basra province between October 2021 and February 2022. The age average for the study population was (25-80) years. Serum and blood levels of human CBC, ESR, CRP, Ferritin, D-Dimer, IL 6, Albumin, FBS, HbA1c, Troponin, Cholesterol, Triglyceride, HDL, LDL, VLDL, Creatinine, Urea, Uric acid and GFR were measured. The results show a highly significant increase in WBcs, ESR, CRP, Ferritin, D-Dimer, IL-6, Creatinine, Urea and Uric acid. , and a highly significant decrease in lymphocyte, albumin, HDL and GFR for patients compared to the control group as a total number and the number of males and females separately, While the results of comparing biochemical markers in the patients infected with Coronavirus and who had a diabetic complication a higher significant increase than patients without diabetic complication. The study of these biomarkers provides a dynamic approach to understanding the disease to diagnosis and follow-up, so as to improve the development of patients' treatment and study the relationship between these biomarkers for COVID-19 patients with and without Diabetes Mellitus.

The Study of Biomarkers inSmokers Infected with Covid-19 in Basra, Iraq

Background: The COVID-19 pandemic has heightened awareness of infectious illnesses and their links to host variables and underlying disorders. Objectives: In this review, we look at current research on a possible link between smoking and COVID-19 and study the biomarker changes in patients. Material and Methods: A case-control study included 45 smoker’s patients with COVID-19 and 50 healthy subjects as a control group who visited Al-Basra Teaching Hospital and Allmwanei Hospital in Al-Basra province between October 2021 and February 2022. The age average for the study population was (25-80) years. Serum and blood levels of human CBC, ESR, CRP, Ferritin, D-Dimer, IL 6, Albumin, FBS, HbA1c, Troponin, Cholesterol, Triglyceride, HDL, LDL, VLDL, Creatinine, Urea, Uric acid and GFR were measured. Results: The results show all biomarkers tend to have high sensitivity and specificity for smoker COVID patients based on the ROC curve analysis: Lymphocyte, CRP, Ferritin, D-Dimer, IL 6, Albumin, FBS, HDL, Creatinine, Urea, and GFR. These biomarkers might be helpful in determining the kind and severity of COVID-19 in smokers. Although the data is limited to a total number of patients. Conclusion: Studying patient alterations and vital signs led to the conclusion that smoking and COVID-19 are related. It was also verified that all vital indicators had strong sensitivity and specificity for smoking COVID patients.

Impact of human serum albumin level on symptomatic cerebral vasospasm in patients with aneurysmal subarachnoid hemorrhage.

To investigate the impact of human serum albumin (HSA) levels on symptomatic cerebral vasospasm (SCVS) in patients with aneurysmal subarachnoid hemorrhage (aSAH). We retrospectively reviewed the medical records. SCVS was defined as the development of a new neurological deterioration when the cause was considered to be ischemia attributable to vasospasm after other possible causes of worsening had been excluded. The aSAH patients were divided into two groups: those with SCVS (group 1) and those without SCVS (group 2). The HSA level data on the 1st, 2nd, and 3rd day after admission was collected. Multivariate logistical regression and receiver operating characteristic (ROC) analysis were performed to evaluate the ability of HSA level to predict the development of SCVS. A total of 270 patients were included in our study, of which 74 (27.4%) developed SCVS. The average and lowest HSA levels were lower in group 1 (P < 0.001). In univariate logistic regression, white blood cell count, neutrophil count, and average and lowest HSA levels were associated with SCVS. After adjustment for age, CT Fisher grade, Hunt-Hess grade, and WFNS grade, both the average and lowest HSA levels remained independent predictors of SCVS (P < 0.001). The CT Fisher grade was confirmed to be an independent predictor of SCVS across each model. ROC analysis revealed that the lowest HSA level was a better predictor for SCVS than average HSA level and CT Fisher grade. Clinicians are encouraged to measure HSA levels for the first 3 days after admission to predict the occurrence of SCVS after aSAH.

Relationship between human serum albumin and in-hospital mortality in critical care patients with chronic obstructive pulmonary disease.

The relationship between human serum albumin levels and the prognosis of critical care patients with chronic obstructive pulmonary disease (COPD) remains controversial. To investigate the relationship between serum albumin levels and in-hospital mortality in critical care patients with COPD. METHODS: This study used a retrospective observational cohort from the Medical Information in Intensive Care database (MIMIC-IV) in the United States. Multivariate Cox regression analysis was used to assess the relationship between serum albumin levels and in-hospital mortality. A restricted cubic spline line was also used to explore nonlinear relationship. A total of 3,398 critical care patients with COPD were included. The overall in-hospital mortality was 12.4%. We found a negative relationship between human serum albumin and in-hospital mortality (HR = 0.97, 95% CI 0.96-0.99, p = 0.002). In critical care patients with COPD, there was a negative association between human serum albumin and in-hospital mortality.

AIE-based fluorescence probes with different torsional configurations for monitoring human serum albumin

Human serum albumin (HSA) levels can reflect a variety of health issues in the human body, and quantitative examination of HSA is of great significance for disease diagnosis. Herein, we rationally designed and developed two novel AIE small molecule fluorescent probes, AE-BP and AE-AQ. Two probes have various torsion configurations and can be applied to the detection of exogenous HSA. They have high signal-to-noise ratio and selectivity and can enter the HSA cavity smoothly. Both probes can combine with the IB site, successfully avoiding most drug interference and having different detection effects on HSA. Meanwhile, the rational mechanism of AE-BP and AE-AQ to perform target detection was investigated using density functional theory. Furthermore, the scientific problems associated with the high signal-to-noise ratio and low aggregation of fluorescent probes were explained by investigating the effects of different torsional configurations on the detection effect. The main factors to be concerned in designing HSA fluorescent probes were proposed. This work provides methods and concepts for designing fluorescent probes for HSA based on the AIE strategy, as well as an effective manner for fluorescent probes to detect HSA. We anticipate that AE-BP and AE-AQ will be employed as new tools for detecting HSA at the preclinical stage.

Serum Albumin Inspired Self-Assembly/Disassembly of a Fluorogenic Nanoprobe for Real-Time Monitoring and Quantification of Urinary Albumin with Live Cell Imaging Application.

Abnormal levels (high/low) of urinary human serum albumin (HSA) are associated with a number of diseases and thus act as an essential biomarker for quick therapeutic monitoring and biomedical diagnosis, entailing the urgent development of an effective chemosensor to quantify the albumin levels. Herein, we have rationally designed and developed a small fluorogenic molecular probe, (Z)-2-(5-((8-hydroxy-2,3,6,7-tetrahydro-1H,5H-pyrido[3,2,1-ij]quinolin-9-yl) methylene)-4-oxo-2-thioxothiazolidin-3-yl) acetic acid (HJRA) with a twisted intramolecular charge transfer (TICT) property, which can easily self-assemble into nonfluorescent nanoaggregates in aqueous solution. However, HJRA nanoaggregates can selectively bind with serum albumin proteins (HSA/BSA) in ∼100% PBS medium, thereby facilitating the disassembly of nanoaggregates into monomers, exhibiting a clear turn-on red fluorescent response toward HSA and BSA. Analysis of the specific binding mechanism between HJRA and HSA using a site-selective fluorescence displacement assay and molecular docking simulations indicates that a variety of noncovalent interactions are responsible for the disassembly of nanoaggregates with the concomitant trapping of the HJRA monomer at site I in HSA, yielding a substantial red emission caused by the inhibition of intramolecular rotation of HJRA probe inside the hydrophobic cavity of HSA. The limit of detection (LOD) determined by the 3σ/slope method was found to be 1.13 nM, which is substantially below the normal HSA concentration level in healthy urine, signifying the very high sensitivity of the probe toward HSA. The comparable results and quick response toward quantification of HSA in urine by HJRA with respect to the Bradford method clearly point toward the superiority of this method compared to the existing ones and may lead to biomedical applications for HSA quantification in urine. It may also find potential application in live-cell imaging of HSA.

Personalized diagnostic approach and indirect quantification of extravasation in human anaphylaxis.

Anaphylaxis is the most acute and life-threatening manifestation of allergic disorders. Currently, there is a need to improve its medical management and increase the understanding of its molecular mechanisms. This study aimed to quantify the extravasation underlying human anaphylactic reactions and propose new theragnostic approaches. Molecular determinations were performed in paired serum samples obtained during the acute phase and at baseline from patients presenting with hypersensitivity reactions. These were classified according to their severity as Grades 1, 2 and 3, the two latter being considered anaphylaxis. Tryptase levels were measured by ImmunoCAP, and serum protein concentration was quantified by Bradford assay. Human serum albumin (HSA) and haemoglobin beta subunit (HBB) levels were determined by Western blot and polyacrylamide gel electrophoresis, respectively. A total of 150 patients were included in the study. Of them, 112 had experienced anaphylaxis (83 and 29 with Grade 2 and 3 reactions, respectively). Tryptase diagnostic efficiency substantially improved when considering patients' baseline values (33%-54%) instead of the acute value threshold (21%). Serum protein concentration and HSA significantly decreased in anaphylaxis (p < .0001). HSA levels dropped with the severity of the reaction (6% and 15% for Grade 2 and 3 reactions, respectively). Furthermore, HBB levels increased during the acute phase of all hypersensitivity reactions (p < .0001). For the first time, the extravasation underlying human anaphylaxis has been evaluated based on the severity of the reaction using HSA and protein concentration measurements. Additionally, our findings propose new diagnostic and potential therapeutic approaches for this pathological event.

Association of albumin, fibrinogen, and modified proteins with acute coronary syndrome.

Acute coronary syndrome (ACS) comprises a pathophysiological spectrum of cardiovascular diseases related to atherosclerotic coronary plaque erosion. Oxidative stress and inflammation play pivotal roles in the development and progression of atherosclerosis, which affects circulatory proteins, including albumin and fibrinogen, thereby causing an imbalance in albumin to globulin and fibrinogen to albumin ratios. This study aimed to assess the effect of oxidative stress on circulatory proteins, correlate these parameters, and investigate their significance in patients with ACS. In this case-control study, the major blood proteins in patients with ACS and a control group were evaluated using standard methods. Out of 70 ACS cases, 75.7% had ST-elevation myocardial infarction (STEMI), 18.6% had non-STEMI, and 5.7% had unstable angina. The mean cardiac troponin I level in patients was 12.42 ng/mL. The patients demonstrated a significantly reduced level of human serum albumin (HSA), 3.81 ± 0.99 g/dL, compared to controls, 5.33 ± 0.66 g/dL. The albumin to globulin ratio (AGR) was significantly depressed in patients while their mean fibrinogen level and the fibrinogen to albumin ratio (FAR) were significantly higher. Multivariate logistic regression analysis showed that albumin and fibrinogen were significantly associated with the risk of ACS, showing the potential of these parameters to be used for risk assessment of ACS. The ischemia modified albumin (IMA) and protein carbonyls were significantly higher in patients which showed significant positive correlations with FAR. Albumin, IMA and protein carbonyls were found to have high diagnostic sensitivity and specificity for ACS. Overall, these circulatory and modified proteins in ACS patients, particularly lower HSA, AGR, and higher IMA and protein carbonyls may help assess risk.

Simultaneous measurement of mouse and human albumin in chimeric mice with humanized livers.

Background: The degree of human hepatocyte replacement inchimeric mice with humanized liver has previously been shown to correlate with human plasma albumin measurements. However, there are no reportsthatdirectly comparetheremaining endogenous mouse albumin with the newly expressed human albumin following engraftment. To better understand the disposition of serum albumin in PXB-mice, we developed aliquid chromatographytandem mass spectrometry (LC-MS/MS) method to simultaneously quantitate both human and mouse albumin from plasma. Results: A robust correlation was observed between the serum human albumin levels measured by LC-MS/MS and the estimated replacement index of PXB-mice. Conclusion: All data wereshown to be specific and suitable to accurately quantify both human and mouse albumin from plasma of chimeric mice with humanized livers.

Limited Expansion of Human Hepatocytes in FAH/RAG2-Deficient Swine.

The mammalian liver's regenerative ability has led researchers to engineer animals as incubators for expansion of human hepatocytes. The expansion properties of human hepatocytes in immunodeficient mice are well known. However, little has been reported about larger animals that are more scalable and practical for clinical purposes. Therefore, we engineered immunodeficient swine to support expansion of human hepatocytes and identify barriers to their clinical application. Immunodeficient swine were engineered by knockout of the recombinase-activating gene 2 (RAG2) and fumarylacetoacetate hydrolase (FAH). Immature human hepatocytes (ihHCs) were injected into fetal swine by intrauterine cell transplantation (IUCT) at day 40 of gestation. Human albumin was measured as a marker of engraftment. Cytotoxicity against ihHCs was measured in transplanted piglets and control swine. We initially detected higher levels of human albumin in cord blood of newborn FAH/RAG2-deficient (FR) pigs compared with immunocompetent controls (196.26 ng/dL vs. 39.29 ng/dL, p = 0.008), indicating successful engraftment of ihHCs after IUCT and adaptive immunity in the fetus. Although rare hepatocytes staining positive for human albumin were observed, levels of human albumin did not rise after birth, but declined, suggesting rejection of xenografted ihHCs. Cytotoxicity against ihHCs increased after birth by 3.8% (95% CI: [2.1%–5.4%], p < 0.001) and inversely correlated with declining levels of human albumin (p = 2.1 × 10−5, R2 = 0.17). Circulating numbers of T cells and B cells were negligible in FR pigs. However, circulating natural killer (NK) cells exerted cytotoxicity against ihHCs. NK cell activity was lower in immunodeficient piglets after IUCT than in naive controls (30.4% vs. 40.1%, p = 0.011, 95% CI for difference [2.7%–16.7%]). In conclusion, ihHCs were successfully engrafted in FR swine after IUCT. NK cells were a significant barrier to expansion of hepatocytes. New approaches are needed to overcome this hurdle and allow large-scale expansion of human hepatocytes in immunodeficient swine.Impact statementThere is currently a need for robust expansion of human hepatocytes. We describe an immunodeficient swine model into which we engrafted immature human hepatocytes (ihHCs). We identified the mechanism of the eventual graft rejection by the intact NK cell population, which has not been previously shown to have a significant role in xenograft rejection. By both improving engraftment and reducing NK cell-mediated cytotoxicity toward the graft through intrauterine cell transfer, we confirmed the presence of residual adaptive immunity in this model of immunodeficiency and the ability to induce hyposensitization in the NK cell population by taking advantage of the fetal microenvironment.

Loss of Dihydroxyacid Dehydratase Induces Auxotrophy in Bacillus anthracis.

Anthrax disease is caused by infection with the bacteria Bacillus anthracis which, if left untreated, can result in fatal bacteremia and toxemia. Current treatment for infection requires prolonged administration of antibiotics. Despite this, inhalational and gastrointestinal anthrax still result in lethal disease. By identifying key metabolic steps that B. anthracis uses to grow in host-like environments, new targets for antibacterial strategies can be identified. Here, we report that the ilvD gene, which encodes dihydroxyacid dehydratase in the putative pathway for synthesizing branched chain amino acids, is necessary for B. anthracis to synthesize isoleucine de novo in an otherwise limiting microenvironment. We observed that ΔilvD B. anthracis cannot grow in media lacking isoleucine, but growth is restored when exogenous isoleucine is added. In addition, ΔilvD bacilli are unable to utilize human hemoglobin or serum albumin to overcome isoleucine auxotrophy, but can when provided with the murine forms. This species-specific effect is due to the lack of isoleucine in human hemoglobin. Furthermore, even when supplemented with physiological levels of human serum albumin, apotransferrin, fibrinogen, and IgG, the ilvD knockout strain grew poorly relative to nonsupplemented wild type. In addition, comparisons upon infecting humanized mice suggest that murine hemoglobin is a key source of isoleucine for both WT and ΔilvD bacilli. Further growth comparisons in murine and human blood show that the auxotrophy is detrimental for growth in human blood, not murine. This report identifies ilvD as necessary for isoleucine production in B. anthracis, and that it plays a key role in allowing the bacilli to effectively grow in isoleucine poor hosts. IMPORTANCE Anthrax disease, caused by B. anthracis, can cause lethal bacteremia and toxemia, even following treatment with antibiotics. This report identifies the ilvD gene, which encodes a dihydroxyacid dehydratase, as necessary for B. anthracis to synthesize the amino acid isoleucine in a nutrient-limiting environment, such as its mammalian host. The use of this strain further demonstrated a unique species-dependent utilization of hemoglobin as an exogenous source of extracellular isoleucine. By identifying mechanisms that B. anthracis uses to grow in host-like environments, new targets for therapeutic intervention are revealed.

The effect of intestinal ischemia on plasma thiol/disulphide homeostasis in an experimental study

Aim: To investigate the effects of acute intestinal ischemia on plasma thiol/disulphide homeostasis (TDSH), which has been investigated in a limited number of studies in the related literature. Methods: Twenty-four rats were randomized into control (operation without ischemia, GIS), and ischemia groups (GII-60, GIII-180). For ischemia, the superior mesenteric artery was sutured and the rats were exposed to 60 and 180 minutes of intestinal ischemia, respectively. Plasma TDSH was measured in blood samples collected at the end of the ischemia, and the pathology of ileum segments resected was evaluated. Results: The experimental ischemic conditions provided were confirmed by the total histopathological scoring system statistically. The levels of serum human albumin and ischemia modified albumin (IMA) in groups were detected in quite a close range of each other. There was no found a statistically significant difference for IMA between groups (p>0.05). The alternations on the levels of plasma TDSH parameters were observed in the study. According to ischemic conditions, the thiol/disulfide ratio fluctuations were detected in the plasma TDSH. The native thiol and total thiol levels seem to have decreased according to ischemia; no statistical difference was detected. In addition, the disulfide levels increasing according to ischemia either was not found significant statistically (p>0.05). Conclusion: Although this study showed the oxidative balance in intestinal ischemia had affected plasma TDSH, also it revealed that intestinal ischemia didn't create a statistically significant difference between plasma TDSH components.

COVID-19 vulnerabilities are intensified by declining human serum albumin levels.

What is the topic of this review? Human serum albumin (HSA) a common factor in COVID‐19 vulnerabilities. What advances does it highlight? Understanding of HSA capacity, and systemic vulnerabilities to COVID‐19. Raising HSA in COVID‐19 patients may alleviate systemic injury caused by diminished native HSA binding. A change in fluid therapy administration into the portal system of the liver is proposed to safely raise HSA levels. The specific nature of the vulnerabilities to COVID‐19 are an intrinsic part of COVID‐19 infection in many patients. This paper proposes that vulnerabilities to COVID‐19 may be intensified by a decrease in human serum albumin (HSA) as a ligand carrier for nutrients. A mechanism for COVID‐19 vulnerabilities is evident from consideration of ligand carriers such as HSA as intermediaries. We hypothesise that low levels of pool HSA binding, caused for whatever reason, affect the performance of albumin as a carrier protein reducing the availability of nutrients. Hypoalbuminaemia (low HSA) has been implicated as an indicator of COVID‐19 and long‐COVID‐19. The levels of HSA directly affect the immune system and vulnerabilities to age, diabetes and obesity in COVID‐19. Any slight reduction in available HSA has profound effects on ligand concentrations in the small capillaries where damage occurs in COVID‐19. The clinical implication is that attempts should be made to return HSA to clinical levels to compensate for the additional ligands caused by infection (SARS‐CoV‐2 virions, antibodies and cellular breakdown products). Therapeutic albumin is usually given peripherally, and usual preparations are unbound to ligands, but we suggest that a clinical trial of HSA therapy via the hepatic portal vein should be considered.