Branched-chain amino acids and the risks of dementia, Alzheimer's disease, and Parkinson's disease.

Background: We aimed to examine the association between blood levels of Branched-chain amino acids (BCAAs) - specifically isoleucine, leucine, and valine - and the susceptibility to three neurodegenerative disorders: dementia, Alzheimer's disease (AD), and Parkinson's disease (PD). Methods: Based on data from the UK Biobank, a Cox proportional hazard regression model and a dose-response relationship were used to analyze the association between BCAAs and the risks of dementia, AD, and PD. We also generated a healthy lifestyle score and a polygenic risk score. Besides, we conducted a sensitivity analysis to ensure the robustness of our findings. Results: After adjusting for multiple covariates, blood concentrations of isoleucine, leucine, and valine were significantly associated with a reduced risk of dementia and AD. This association remained robust even in sensitivity analyses. Similarly, higher levels of isoleucine and leucine in the blood were found to be associated with an increased risk of PD, but this positive correlation could potentially be explained by the presence of covariates. Further analysis using a dose-response approach revealed that a blood leucine concentration of 2.14 mmol/L was associated with the lowest risk of dementia. Conclusion: BCAAs have the potential to serve as a biomarker for dementia and AD. However, the specific mechanism through which BCAAs are linked to the development of dementia, AD, and PD remains unclear and necessitates additional investigation.

Plasma lipidomic profiling reveals six candidate biomarkers for the prediction of incident stroke in patients with hypertension.

INTRODUCTION: The burden of stroke in patients with hypertension is very high, and its prediction is critical. OBJECTIVES: We aimed to use plasma lipidomics profiling to identify lipid biomarkers for predicting incident stroke in patients with hypertension. METHODS: This was a nested case-control study. Baseline plasma samples were collected from 30 hypertensive patients with newly developed stroke, 30 matched patients with hypertension, 30 matched patients at high risk of stroke, and 30 matched healthy controls. Lipidomics analysis was performed by ultrahigh-performance liquid chromatography-tandem mass spectrometry, and differential lipid metabolites were screened using multivariate and univariate statistical methods. Machine learning methods (least absolute shrinkage and selection operator, random forest) were used to identify candidate biomarkers for predicting stroke in patients with hypertension. RESULTS: Co-expression network analysis revealed that the key molecular alterations of the lipid network in stroke implicate glycerophospholipid metabolism and choline metabolism. Six lipid metabolites were identified as candidate biomarkers by multivariate statistical and machine learning methods, namely phosphatidyl choline(40:3p)(rep), cholesteryl ester(20:5), monoglyceride(29:5), triglyceride(18:0p/18:1/18:1), triglyceride(18:1/18:2/21:0) and coenzyme(q9). The combination of these six lipid biomarkers exhibited good diagnostic and predictive ability, as it could indicate a risk of stroke at an early stage in patients with hypertension (area under the curve = 0.870; 95% confidence interval: 0.783-0.957). CONCLUSIONS: We determined lipidomic signatures associated with future stroke development and identified new lipid biomarkers for predicting stroke in patients with hypertension. The biomarkers have translational potential and thus may serve as blood-based biomarkers for predicting hypertensive stroke.

Single-Molecule Dendritic MRI Nanoprobes Reveal the Size-Dependent Tumor Entrance.

The tumor entrance of drug delivery systems, including therapeutic proteins and nanomedicine, plays an essential role in affecting the treatment outcome. Nanoparticle size is a critical but contradictory factor in making a trade-off among blood circulation, tumor accumulation, and penetration. Here, this work designs a series of single-molecule gadolinium (Gd)-based magnetic resonance imaging (MRI) nanoprobes with well-defined sizes to precisely explore the size-dependent tumor entrance in vivo. The MRI nanoprobes obtained by divergent synthesis contain a core molecule of macrocyclic Gd(III)-chelate and different layers of dendritic lysine units, mimicking globular protein. This work finds that the r1 relaxivity and MR imaging signals increase with the nanoparticle size. The nanoprobe with a lower limit of critical size threshold ≈8.0 nm achieves superior tumor accumulation and penetration. These single-molecule MRI nanoprobes can be served to precisely examine the size-related nanoparticle-biological interactions.

Surface chemistry mediates the tumor entrance of nanoparticles probed using single-molecule dual-imaging nanodots.

The active transport of nanoparticles into solid tumors through transcytosis has been recognized as a promising way to enhance tumor accumulation and penetration, but the effect of the physicochemical properties of nanoparticles remains unclear. Herein, we develop a type of single-molecule dual imaging nanodot by divergent growth of perylenediimide (PDI)-dye-cored polylysine dendrimers and internal orthogonal conjugation of Gd(III)-based macrocyclic probes for fluorescence imaging and magnetic resonance imaging (MRI) of surface chemistry-dependent tumor entrance. The MRI and fluorescence imaging show that sixth-generation nanodots with acetylated (G6-Ac) and oligo ethylene glycol (G6-OEG) surfaces exhibit similar high tumor accumulation but different intratumor distribution. Cellular uptake and transport experiments suggest that G6-Ac nanodots have lower lysosomal entrapment (61% vs. 83%) and a higher exocytotic rate (47% vs. 29%) than G6-OEG. Therefore, G6-Ac is more likely to undergo intercellular transport through cell transcytosis, and is able to reach a tumor area distant from blood vessels, while G6-OEG mainly enters the tumor through enhanced permeability and retention (EPR) effect-based passive transport, and is not able to deliver to distant tumor areas. This study suggests that it is possible to boost the tumor entrance of nanoparticles by engineering surface chemistry for active transport.

Supramolecular metal-organic frameworks as host-guest nanoplatforms for versatile and customizable biomedical applications.

Molecular imaging of disease with multifunctional nanoparticles has improved specificity and sensitivity but also raises the complexity, potential toxicity, and cost. Here, we show a facile and degradable self-assembly ß-cyclodextrin metal-organic framework (ß-CD-MOF) nanoplatform for customizable multifunctional imaging. These ß-CD-MOF nanoparticles were obtained with favorable morphology and size by controlling the degradation time. The ß-CD-MOF were used as nanoplatforms for facile functionalization with adamantane (Ad)-modified probes through host-guest interactions between the surface ß-CD units and Ad molecules. We demonstrated the method's feasibility and capability by developing various contrast agents for multiple biomedical imaging, including fluorescence imaging, magnetic resonance imaging (MRI), and computed tomography (CT) imaging. The nanoprobes showed superior performance compared to the corresponding small molecular probes, including better physio-chemical properties (e.g., about 5 times of T1 relaxivity for MRI, 1.2 times of Hounsfield units for CT), improved pharmacokinetics, effective tissue imaging capability, and low safety concerns. These ß-CD-MOF-based nanoparticles are promising host-guest nanoplatforms for developing multifunctional and safe imaging probes. STATEMENT OF SIGNIFICANCE: Molecular imaging of disease with multifunctional nanoparticles has improved specificity and sensitivity but also raises the complexity, potential toxicity, and cost. Here, we introduce facile and degradable self-assembly ß-cyclodextrin metal-organic framework (ß-CD-MOF) nanoplatforms for customizable multifunctional imaging. The significance of this work includes: 1) This work reports the tailoring of MOFs nanoparticles with suitable sizes and shapes for biomedical applications through controllable morphological transition and degradation; 2) The ß-CD-MOF-based host-guest nanoplatforms are facile and feasible for developing multifunctional nanoparticular contrast agents for effective tissue imaging; 3) The nanoparticular contrast agents show low safety concerns with a long-term tissue deposition similar to the small molecular probes.

Nutritional deficiencies in low-sociodemographic-index countries: a population-based study.

Background: We aimed to estimate the burden of nutritional deficiency according to sex and age in countries with a low sociodemographic index (SDI). Methods: Following the methods of the Global Burden of Diseases, Injuries, and Risk Factors Study 2019, estimated annual percentage changes (EAPCs) were calculated to determine trends in the age-standardized rates of incidence and disability-adjusted life-years (DALYs) of nutritional deficiency and its main subcategories from 1990 to 2019 in low-SDI countries. Findings: From 1990 to 2019, the age-standardized incidence and DALY rates of nutritional deficiency showed decreasing trends, with EAPCs of -0.90 [95% confidence interval (CI), 1.06 to -0.75] and -3.20 (95% CI, -3.29 to -3.10), respectively, in low-SDI countries. In 2019, of the subcategories analyzed, vitamin A deficiency had the highest age-standardized incidence rate and protein-energy malnutrition had the highest age-standardized DALY rate. From 1990 to 2019, the greatest decrease in the age-standardized incidence rate was observed for vitamin A deficiency and the greatest decrease in the age-standardized DALY rate was observed for protein-energy malnutrition. At the national level, from 1990 to 2019, the greatest increase in the age-standardized incidence rate of overall nutritional deficiency was observed in males in Afghanistan (EAPC: 0.28; 95% CI, 0.07 to 0.49). Of the age groups analyzed, the highest incidence and DALY rates of overall nutritional deficiency and dietary iron deficiency were observed in children aged 1-4 years. Interpretation: The age-standardized incidence and DALY rates of nutritional deficiency decreased significantly from 1990 to 2019, especially for vitamin A deficiency and protein-energy malnutrition. Overall nutritional deficiency and dietary iron deficiency occurred primarily in children aged 1-4 years.

Liver fibrosis therapy based on biomimetic nanoparticles which deplete activated hepatic stellate cells.

Liver fibrosis is one of the most common liver diseases with substantial morbidity and mortality. However, effective therapy for liver fibrosis is still lacking. Considering the key fibrogenic role of activated hepatic stellate cells (aHSCs), here we reported a strategy to deplete aHSCs by inducing apoptosis as well as quiescence. Therefore, we engineered biomimetic all-trans retinoic acid (ATRA) loaded PLGA nanoparticles (NPs). HSC (LX2 cells) membranes, presenting the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), were coated on the surface of the nanoparticles, while the clinically approved agent ATRA with anti-fibrosis ability was encapsulated in the inner core. The biomimetic coating of TRAIL-expressing HSC membranes does not only provide homologous targeting to HSCs, but also effectively triggers apoptosis of aHSCs. ATRA could induce quiescence of activated fibroblasts. While TM-NPs (i.e. membrane coated NPs without ATRA) and ATRA/NPs (i.e. non-coated NPs loaded with ATRA) only showed the ability to induce apoptosis and decrease the α-SMA expression in aHSCs, respectively, TM-ATRA/NPs induced both apoptosis and quiescence in aHSCs, ultimately leading to improved fibrosis amelioration in both carbon tetrachloride-induced and methionine and choline deficient L-amino acid diet induced liver fibrosis mouse models. We conclude that biomimetic TM-ATRA/NPs may provide a novel strategy for effective antifibrosis therapy.

Wavelength and frequency optimization in spatial frequency domain imaging for two-layer tissue.

Spatial frequency domain imaging is a non-contact, wide-field, fast-diffusion optical imaging technique, which in principle uses steady-state spatially modulated light to irradiate biological tissue, reconstruct two-dimensional or three-dimensional tissue optical characteristic map through optical transmission model, and further quantify the spatial distribution of tissue physiological parameters by multispectral imaging technique. The selection of light source wavelength and light field spatial modulation frequency is directly related to the accuracy of tissue optical properties and tissue physiological parameters extraction. For improvement of the measurement accuracy of optical properties and physiological parameters in the two-layer tissue, a multispectral spatial frequency domain imaging system is built based on liquid crystal tunable filter, and a data mapping table of spatially resolved diffuse reflectance and optical properties of two-layer tissue is established based on scaling Monte Carlo method. Combined with the dispersion effect and window effect of light-tissue interaction, the study applies numerical simulation to optimize the wavelength in the 650-850 nm range with spectral resolution of 10 nm. In order to minimize the uncertainty of the optical properties, Cramér-Rao bound is used to optimize the optical field spatial modulation frequency by transmitting the uncertainty of optical properties. The results showed that in order to realize the detection of melanin, oxyhemoglobin, deoxyhemoglobin, water and other physiological parameters in two-layer tissue, the best wavelength combination was determined as 720, 730, 760 and 810 nm according to the condition number. The findings of the Cramér-Rao bound analysis reveal that the uncertainty of optical characteristics for the frequency combinations [0, 0.3] mm-1, [0, 0.2] mm-1, and [0, 0.1] mm-1 increases successively. Under the optimal combination of wavelength and frequency, the diffuse reflectance of the gradient gray-scale plate measured by the multi-spectral spatial frequency domain imaging system is linearly correlated with the calibration value. The error between the measured liquid phantom absorption coefficient and the collimation projection system based on colorimetric dish is less than 2%. The experimental results of human brachial artery occlusion indicate that under the optimal wavelength combination, the change of the second layer absorption coefficient captured by the three frequency combinations decreases in turn, so as the change of oxygen saturation.

Global, Regional, and National Burden of Cancer in Children Younger Than 5 Years, 1990-2019: Analysis of the Global Burden of Disease Study 2019.

Objectives: To quantify the burden and variation trends of cancers in children under 5 years at the global, regional, and national levels from 1990 to 2019. Methods: Epidemiological data for children under 5 years who were diagnosed with any one childhood cancer were obtained from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) from 1990 to 2019. The outcomes were the absolute numbers and rates of incidence, prevalence, mortality, and disability-adjusted life-years (DALYs) for different types of cancer. Results: In 2019, 8,774,979.1 incident cases (95% uncertainty interval [UI]: 6,243,599.2 to11,737,568.5) and 8,956,583.8 (6,446,323.9 to 12,364,520.8) prevalent cases of cancer in children under 5 years were identified worldwide; these cancers resulted in 44,451.6 (36,198.7 to 53,905.9) deaths and 3,918,014.8 (3,196,454.9 to 4,751,304.2) DALYs. From 1990 to 2019, although the numbers of incident and prevalent cases only decreased by -4.6% (-7.0 to -2.2) and -8.3% (-12.6 to -3.4), respectively, the numbers of deaths and DALYs clearly declined by -47.8% (-60.7 to -26.4) and -47.7% (-60.7 to -26.2), respectively. In 2019, the middle sociodemographic index (SDI) regions had the highest incidence and prevalence, whereas the low SDI regions had the most mortality and DALYs. Although all of the SDI regions displayed a steady drop in deaths and DALYs between 1990 and 2019, the low-middle and low SDI regions showed increasing trends of incidence and prevalence. Leukemia remained the most common cancer globally in 2019. From 1990 to 2019, the burdens of leukemia, liver cancer, and Hodgkin's lymphoma declined, whereas the incidence and prevalence of other cancers grew, particularly testicular cancer. Conclusions: The global childhood cancer burden in young children has been steadily decreasing over the past three decades. However, the burdens and other characteristics have varied across different regions and types of cancers. This highlights the need to reorient current treatment strategies and establish effective prevention methods to reduce the global burden of childhood cancer.

Nanoprodrug ratiometrically integrating autophagy inhibitor and genotoxic agent for treatment of triple-negative breast cancer.

Effective combination therapies are urgently needed to treat triple-negative breast cancer (TNBC), which is insensitive to the existing treatment regimens. However, the synergistic potency of traditional small-molecule combinations is limited in TNBC mainly due to mismatched molar ratios, inconsistent pharmacokinetics, and intratumoral accumulation of individual drugs. Here, we find that the autophagy inhibitor hydroxychloroquine (HCQ) and the topoisomerase I inhibitor 7-ethyl-10-hydroxycamptothecin (SN38) exhibit synergistic effects when the molar ratio reaches 5:1. We further develop a glutathione-responsive self-assembled combination nanoparticle (Combo NP) to integrate individual HCQ and SN38 polymeric prodrugs at the optimized ratio. In TNBC cells treated with Combo NP, HCQ-mediated autophagy blockage significantly enhances the DNA damage and apoptotic effect of SN38, manifesting synergistically cytotoxic effects of Combo NP. In vivo evaluations show that Combo NP maintains the molar ratio of HCQ to SN38 within the synergistic range in mouse blood circulation and intratumoral tissues. More importantly, Combo NP elicits superior therapeutic benefit in metastatic TNBC models, compared to free drug combination as well as single drug nanoparticles. Taken together, our engineered nanosystem highlights a nanoprodrug-based chemosensitizing approach for improving the therapeutic response to TNBC, addressing the major challenges of the current combination therapy.

Evaluation of small dense low-density lipoprotein concentration for predicting the risk of acute coronary syndrome in Chinese population.

BACKGROUND: Acute coronary syndrome (ACS) is the leading cause of death in developing and developed countries, yet assessing the risk of its development remains challenging. Several lines of evidence indicate that small, dense low-density lipoproteins (sd-LDL) are associated with increased cardiovascular disease risk. We aim to evaluate sd-LDL concentration for predicting the risk of ACS in Chinese population. METHODS: Baseline characteristics of 121 patients with ACS and 172 healthy controls were obtained. Plasma sd-LDL-C was measured using homogeneous assay, and the proportion of sd-LDL-C in LDL-C was detected. RESULTS: There was gender and age effect on the sd-LDL-C concentration and sd-LDL-C/LDL-C ratio among healthy subjects. Elevated sd-LDL-C concentrations and sd-LDL-C/LDL-C ratio were observed in ACS patients with unstable angina pectoris (UAP), non-ST-segment elevation myocardial infarction (STEMI), and ST-segment elevation myocardial infarction (NSTEMI) compared with healthy controls (P < .05); however, there were no differences among ACS groups. According to Pearson's correlation coefficient analyses, sd-LDL-C concentration and sd-LDL-C/LDL-C ratio were positively correlated with triglyceride (TG) and LDL-C concentrations (P < .05) and negatively correlated with high-density lipoprotein (HDL) concentration (P < .05). Based on the receiver operating characteristic (ROC) curves, the cutoff values of sd-LDL-C and sd-LDL-C/LDL-C ratio for the prediction of ACS were 1.06 mmol/L and 34.55%, respectively. Multivariate logistic regression analysis demonstrated that the sd-LDL-C/LDL-C ratio, but not sd-LDL-C concentration, was significantly associated with ACS events [OR (95% CI): 1.24, 1.11-1.38, P < .001]. CONCLUSIONS: The sd-LDL-C/LDL-C ratio may be associated with an increased risk of developing ACS in Chinese population.

Adenosine A2A receptor deficiency prevents p38MAPK activation and apoptosis of mouse hippocampal cells in the chronic hypoxic-hypercapnia model.

This study aims to study the effects of adenosine A2A receptor (A2AR) on hippocampal cell apoptosis and the putative mechanisms in a mouse model of chronic hypoxic-hypercapnia. Wild-type (WT) or A2AR knockout (A2AR KO) mice were randomly divided into normal control (NC) groups and chronic hypoxic-hypercapnia (4HH) groups. Compared with their corresponding NC groups (WT-NC and KO-NC), the apoptosis index (AI), caspase-3 activity, Bax mRNA and P-p38 protein expression in the hippocampus of 4HH groups (WT-4HH and KO-4HH) were significantly increased, while Bcl2 mRNA expression was significantly decreased (P < 0.05). Moreover, A2AR deficiency significantly rescued the effect of chronic hypoxic-hypercapnia on apoptosis when compared with the WT-4HH group (P < 0.05). A2AR deficiency inhibits hippocampal cell apoptosis in mice exposed to chronic hypoxic-hypercapnia, which might be associated with dampened p38 MAPK activation and Bax mRNA expression, and augmented Bcl-2 mRNA expression.

Immunoassay of S-adenosylmethionine and S-adenosylhomocysteine: the methylation index as a biomarker for disease and health status.

BACKGROUND: S-Adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH) are relevant to a variety of diseases. Previous reports that quantified SAM and SAH were based on HPLC or LC-MS/MS. No antibody against SAM has been generated, and the antibody against SAH cannot be used with blood samples. Immunoassays have not been used to measure SAM and SAH. In this study, ELISA was used to measure blood SAM and SAH levels. RESULTS: Specific antibodies against SAM were produced for the first time using a stable analog as the antigen. The monoclonal antibodies against SAM and SAH were characterized. No cross-reactivity was detected for the analyzed analogs. For the anti-SAM antibodies, the ELISA sensitivity was ~2 nM, and the affinity was 7.29 × 1010 L/mol. For the anti-SAH antibodies, the sensitivity was ~15 nM, and the affinity was 2.79 × 108 L/mol. Using high-quality antibodies against SAM and SAH, immunoassays for the detection of SAM and SAH levels in blood and tissue samples were developed. Clinical investigations using immunoassays to measure SAM, SAH and the methylation index (MI) in normal and diseased samples indicated that (1) the SAM level is age and gender dependent; (2) the SAM level is associated with the severity of liver diseases, inflammatory reactions and other diseases; and (3) the methylation index (MI) is significantly reduced in many diseases and may serve as a screening biomarker to identify potentially unfavorable health conditions. CONCLUSION: It is possible to generate antibodies against active small biomolecules with weak immunogenicity, such as SAM and SAH, using traditional hybridoma technology. The antigens and antibodies described here will contribute to the development of immunoassays to measure SAM, SAH and related molecules. These assays enable the MI to be measured specifically, accurately, easily and quickly without costly equipment. This preliminary study indicates that the MI could be an effective indicator of general health, except under conditions that may alter the value of the MI, such as special diets and medications.

Proteomic analysis of cerebrospinal fluid in amyotrophic lateral sclerosis.

The present study used comparative proteomic analysis of cerebrospinal fluid (CSF) in amyotrophic lateral sclerosis (ALS) patients in order to identify proteins that may act as diagnostic biomarkers and indicators of the pathogenesis of ALS. This analysis was performed using isobaric tags for relative and absolute quantitation (iTRAQ) technology, coupled with 2-dimensional liquid chromatography/mass spectrometry. Database for Annotation, Visualization and Integrated Discovery software was utilized for bioinformatic analysis of the data. Following this, western blotting was performed in order to examine the expression of 3 candidate proteins in ALS patients compared with healthy individuals [as a normal control (NC) group] or patients with other neurological disease (OND); these proteins were insulin-like growth factor II (IGF-2), glutamate receptor 4 (GRIA4) and leucine-rich α-2-glycoprotein 1 (LRG1). Clinical data, including gender, age, disease duration and ALS functional rating scale (ALSFRS-R) score, were also collected in the ALS patients. Multiple linear regression analysis was performed between the clinical data and the results of western blot analysis. A total of 248 distinct proteins were identified in the ALS and NC groups, amongst which a significant difference could be identified in 35 proteins; of these, 21 proteins were downregulated and 14 were upregulated. These differentially-expressed proteins were thus revealed to be associated with ALS. The western blot analysis confirmed a proportion of the data attained in the iTRAQ analysis, revealing the differential protein expression of IGF-2 and GRIA4 between the ALS and NC groups. IGF-2 was significantly downregulated in ALS patients (P=0.017) and GRIA4 was significantly upregulated (P=0.016). These results were subsequently validated in the 35-patient ALS and OND groups (P=0.002), but no significant difference was identified in LRG1 expression between these groups. GRIA4 protein expression was higher in male than female patients and was positively correlated with the ALSFRS-R score, meaning that GRIA4 expression was negatively correlated with the severity of ALS, while IGF-2 and LRG1 expression did not correlate with any clinical data. The present study thus demonstrated that GRIA4 expression levels, as a marker of severity, may be used as a reference for the timing of treatment, and that IGF-2 may serve as an effective biomarker of ALS progression.

Expression of human alpha-galactosidase and alpha1,2-fucosyltransferase genes modifies the cell surface Galalpha1,3Gal antigen and confers resistance to human serum-mediated cytolysis.

OBJECTIVE: To explore the strategies which reduce the amount of xenoantigen Galalpha1,3Gal. METHODS: Human alpha-galactosidase gene and alpha1,2-fucosyltransferase gene were transferred into cultured porcine vascular endothelial cells PEDSV.15 and human alpha-galactosidase transgenic mice were produced. The Galalpha1,3Gal on the cell surface and susceptibility of cells to human antibody-mediated lysis were analyzed. RESULTS: Human alpha-galactosidase gene alone reduced 78% of Galalpha1,3Gal on PEDSV.15 cell surface while human alpha-galactosidase combined with alpha1,2-fucosyltransferase genes removed Galalpha1,3Gal completely. Decrease of Galalpha1,3Gal could reduce susceptibility of cells to human antibody-mediated lysis, especially during co-expression of alpha-galactosidase gene and alpha1,2-fucosyltransferase gene. RT-PCR indicated positive human alpha-galactosidase gene expression in all organs of positive human alpha-galactosidase transgenic F1 mice including heart, liver, kidney, lung, and spleen, the amount of Galalpha1,3Gal antigens on which was reduced largely. 58% of spleen cells from F1 mice were destroyed by complement-mediated lysis compared with 24% of those from normal mice. CONCLUSIONS: Human alpha-galactosidase gene and alpha1,2-fucosyltransferase gene effectively reduce the expression of Galalpha1,3Gal antigens on endothelial cell surface and confers resistance to human serum-mediated cytolysis. The expression of human alpha-galactosidase in mice can also eliminate the Galalpha1,3Gal antigens in most tissues and decrease the susceptibility of spleen cells to human serum-mediated cytolysis.