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Chen MY, Duan YL, Zhu Y, Wang JH, Hu QB, Guo SS, Ding BY, Zhang ZF, Li LL. Responses of intestinal morphology, immunity, antioxidant status and cecal microbiota to the mixture of glycerol monolaurate and cinnamaldehyde in laying hens. Poult Sci 2024; 103:103645. [PMID: 38547675 PMCID: PMC11000181 DOI: 10.1016/j.psj.2024.103645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Revised: 03/02/2024] [Accepted: 03/08/2024] [Indexed: 04/11/2024] Open
Abstract
This study was to determine the effects of the mixture of glycerol monolaurate and cinnamaldehyde (GCM) supplementation on the intestinal morphology, immunity, antioxidant status and cecal microbiota of laying hens. A total of 1,120 healthy laying hens (Jingfen-1 strain) at the age of 14 wk were randomly divided into 4 groups with 10 replicates of 28 layers in each and layers were fed diets containing 0 (control group), or 250, 500, and 1,000 mg/kg GCM for 12 wk. The results showed that dietary supplementation with GCM significantly increased intestinal villus height and villus height/crypt depth, duodenal villus area, total superoxide disumutase activities in the liver and jejunum, jejunal glutathione peroxidase activities while decreased duodenal and jejunal crypt depth, hydrogen peroxide content in the liver and jejunal malondialdehyde content of laying hens aging 28 wk (P < 0.05). Meanwhile, GCM addition significantly increased serum immunoglobulin A and immunoglobulin M concentration of layers at the age of 20, 24, and 28 wk (P < 0.05). Moreover, it was observed in the 16S rRNA sequencing that the addition of GCM elevated the abundance and diversity of gut microbiota in laying hens. The predominant bacteria from each group were Bacteroidota and Firmicutes at the phylum level and Bacteroides and Lactobacillus were the dominant genera. The composition and structure of cecal microflora were changed by the addition of GCM to the diet of laying hens. In conclusion, the addition of GCM (500-1,000 mg/kg diet) can improve intestinal morphology, immune function, intestinal and liver antioxidant status and intestinal flora of laying hens, thereby improving intestinal digestion and absorption capacity. These findings provide a new way to further explore the mechanism of GCM improving intestinal health.
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Affiliation(s)
- M Y Chen
- Engineering Research Center of Feed Protein Resources on Agricultural By-Products, Ministry of Education, Hubei Key Laboratory of Animal Nutrition and Feed Science, Wuhan Polytechnic University, Wuhan 430023, China
| | - Y L Duan
- Engineering Research Center of Feed Protein Resources on Agricultural By-Products, Ministry of Education, Hubei Key Laboratory of Animal Nutrition and Feed Science, Wuhan Polytechnic University, Wuhan 430023, China
| | - Y Zhu
- Engineering Research Center of Feed Protein Resources on Agricultural By-Products, Ministry of Education, Hubei Key Laboratory of Animal Nutrition and Feed Science, Wuhan Polytechnic University, Wuhan 430023, China
| | - J H Wang
- Calid biotech (Wuhan) Co., Ltd., Wuhan 430073, China
| | - Q B Hu
- Hunan International Joint Laboratory of Animal Intestinal Ecology and Health, Laboratory of Animal Nutrition and Human Health, Hunan Provincial Key Laboratory of Animal Intestinal Function and Regulation, College of Life Sciences, Hunan Normal University, Changsha 410081, China
| | - S S Guo
- Engineering Research Center of Feed Protein Resources on Agricultural By-Products, Ministry of Education, Hubei Key Laboratory of Animal Nutrition and Feed Science, Wuhan Polytechnic University, Wuhan 430023, China
| | - B Y Ding
- Engineering Research Center of Feed Protein Resources on Agricultural By-Products, Ministry of Education, Hubei Key Laboratory of Animal Nutrition and Feed Science, Wuhan Polytechnic University, Wuhan 430023, China
| | - Z F Zhang
- Engineering Research Center of Feed Protein Resources on Agricultural By-Products, Ministry of Education, Hubei Key Laboratory of Animal Nutrition and Feed Science, Wuhan Polytechnic University, Wuhan 430023, China
| | - L L Li
- Engineering Research Center of Feed Protein Resources on Agricultural By-Products, Ministry of Education, Hubei Key Laboratory of Animal Nutrition and Feed Science, Wuhan Polytechnic University, Wuhan 430023, China.
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2
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Fischer FC, Ludtke S, Thackray C, Pickard HM, Haque F, Dassuncao C, Endo S, Schaider L, Sunderland EM. Binding of Per- and Polyfluoroalkyl Substances (PFAS) to Serum Proteins: Implications for Toxicokinetics in Humans. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:1055-1063. [PMID: 38166384 PMCID: PMC11149785 DOI: 10.1021/acs.est.3c07415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2024]
Abstract
Per- and polyfluoroalkyl substances (PFAS) are a diverse class of highly persistent anthropogenic chemicals that are detectable in the serum of most humans. PFAS exposure has been associated with many adverse effects on human health including immunotoxicity, increased risk of certain cancers, and metabolic disruption. PFAS binding to the most abundant blood serum proteins (human serum albumin [HSA] and globulins) is thought to affect transport to active sites, toxicity, and elimination half-lives. However, few studies have investigated the competitive binding of PFAS to these proteins in human serum. Here, we use C18 solid-phase microextraction fibers to measure HSA-water and globulin-water distribution coefficients (DHSA/w, Dglob/w) for PFAS with carbon chains containing 4 to 13 perfluorinated carbons (ηpfc = 4-13) and several functional head-groups. PFAS with ηpfc < 7 were highly bound to HSA relative to globulins, whereas PFAS with ηpfc ≥ 7 showed a greater propensity for binding to globulins. Experimentally measured DHSA/w and Dglob/w and concentrations of serum proteins successfully predicted the variability in PFAS binding in human serum. We estimated that the unbound fraction of serum PFAS varied by up to a factor of 2.5 among individuals participating in the 2017-2018 U.S. National Health and Nutrition Examination Survey. These results suggest that serum HSA and globulins are important covariates for epidemiological studies aimed at understanding the effects of PFAS exposure.
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Affiliation(s)
- Fabian Christoph Fischer
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Sophia Ludtke
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Colin Thackray
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Heidi M Pickard
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Faiz Haque
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Clifton Dassuncao
- Eastern Research Group, Inc. (ERG), Arlington, Virginia 22201, United States
| | - Satoshi Endo
- National Institute for Environmental Studies (NIES), Health and Environmental Risk Division, Onogawa 16-2, Tsukuba, Ibaraki 305-8506, Japan
| | - Laurel Schaider
- Silent Spring Institute, Newton, Massachusetts 02460, United States
| | - Elsie M Sunderland
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
- Department of Environmental Health, Harvard T.H. Chan School of Public Health, Harvard University, Cambridge, Massachusetts 02138, United States
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3
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Alqhtani AH, Qaid MM, Al-Mufarrej SI, Al-Garadi MA, Ali ABA. Serum biochemistry indices, leukogram, carcass variables and intestinal measurements of Eimeria tenella-infected or non-infected broilers treated with dietary Cinnamomum verum bark. JOURNAL OF APPLIED ANIMAL RESEARCH 2023. [DOI: 10.1080/09712119.2022.2150630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Abdulmohsen H. Alqhtani
- Department of Animal Production, Faculty of Food and Agriculture Sciences, King Saud University, Riyadh, Saudi Arabia
| | - Mohammed M. Qaid
- Department of Animal Production, Faculty of Food and Agriculture Sciences, King Saud University, Riyadh, Saudi Arabia
| | - Saud I. Al-Mufarrej
- Department of Animal Production, Faculty of Food and Agriculture Sciences, King Saud University, Riyadh, Saudi Arabia
| | - Maged A. Al-Garadi
- Department of Animal Production, Faculty of Food and Agriculture Sciences, King Saud University, Riyadh, Saudi Arabia
| | - Ahmed B. A. Ali
- Department of Animal and Veterinary Science, Clemson University, Clemson, SC, USA
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He Y, Miggiels P, Drouin N, Lindenburg PW, Wouters B, Hankemeier T. An automated online three-phase electro-extraction setup with machine-vision process monitoring hyphenated to LC-MS analysis. Anal Chim Acta 2022; 1235:340521. [DOI: 10.1016/j.aca.2022.340521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 10/07/2022] [Accepted: 10/12/2022] [Indexed: 11/29/2022]
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5
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Saied A, Attia A, El-Kholy M, Reda F, EL Nagar A. Effect of cinnamon oil supplementation into broiler chicken diets on growth, carcass traits, haemato-biochemical parameters, immune function, antioxidant status and caecal microbial count. JOURNAL OF ANIMAL AND FEED SCIENCES 2022. [DOI: 10.22358/jafs/146921/2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Gao J, Liu W, Geng B, Lei Q, Han H, Zhou Y, Liu J, Cao D, Li H, Li F. Effect of Plant Essential Oil on Growth Performance and Immune Function During Rearing Period in Laying Hens. BRAZILIAN JOURNAL OF POULTRY SCIENCE 2020. [DOI: 10.1590/1806-9061-2019-1244] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- J Gao
- Shandong Academy of Agricultural Sciences, China; Sericultural Research Institute of Shandong Province, China
| | - W Liu
- Shandong Academy of Agricultural Sciences, China; Poultry Breeding Engineering Technology Center of Shandong Province, China
| | - B Geng
- Sericultural Research Institute of Shandong Province, China
| | - Q Lei
- Shandong Academy of Agricultural Sciences, China; Poultry Breeding Engineering Technology Center of Shandong Province, China
| | - H Han
- Shandong Academy of Agricultural Sciences, China; Poultry Breeding Engineering Technology Center of Shandong Province, China
| | - Y Zhou
- Shandong Academy of Agricultural Sciences, China; Poultry Breeding Engineering Technology Center of Shandong Province, China
| | - J Liu
- Shandong Academy of Agricultural Sciences, China; Poultry Breeding Engineering Technology Center of Shandong Province, China
| | - D Cao
- Shandong Academy of Agricultural Sciences, China; Poultry Breeding Engineering Technology Center of Shandong Province, China
| | - H Li
- Shandong Academy of Agricultural Sciences, China; Poultry Breeding Engineering Technology Center of Shandong Province, China
| | - F Li
- Shandong Academy of Agricultural Sciences, China; Poultry Breeding Engineering Technology Center of Shandong Province, China
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7
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Dietary supplementation of organic or inorganic chromium modulates the immune responses of broilers vaccinated with Avian Influenza virus vaccine. Animal 2018; 13:983-991. [PMID: 30277192 DOI: 10.1017/s1751731118002379] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Dietary supplementation with the organic chromium (Cr) has been shown to positively affect the immune function of poultry. However, to our knowledge, no experiment has been done to directly compare the impacts of Cr chloride and chromium picolinate (CrPic) on the immune responses of broilers vaccinated with Avian Influenza (AI) virus vaccine. Therefore, the present experiment was conducted to investigate the effects of supplemental Cr sources (Cr chloride and CrPic) and levels on the growth performance and immune responses of broilers vaccinated with AI virus vaccine so as to provide an effective nutritional strategy for improving immune function of broilers. A total of 432 1-day (d)-old male broiler chicks were used in a 1 plus 2×4 design. Chickens were given either a diet without Cr supplementation (control) or diets supplemented with 0.4, 0.8, 1.6, or 3.2 mg Cr/kg as either Cr chloride or CrPic for 42 d. Compared to the control, dietary Cr supplementation had no effect (P>0.05) on average daily gain, average daily feed intake and gain : feed of broilers during the starter and grower phases, but increased (P<0.05) the relative weights of bursa of fabricius on d 21 and thymus, spleen, or bursa of fabricius on d 42, serum antibody titers against AI virus on d 21, 28, 35 and 42, blood T-lymphocyte transformation rate on d 28 and 42, blood T-lymphocyte percentage on d 42, and serum interleukin-2 contents on d 28. Broilers fed the diets supplemented with the inorganic Cr chloride had higher (P<0.05) weights of thymus, spleen and bursa of fabricius than those fed the diets supplemented with the CrPic on d 42. In addition, broilers fed the diets supplemented with the CrPic had higher (P<0.05) antibody titers against AI virus than those fed the diets supplemented with the inorganic Cr chloride on d 21 and 35. These results indicate that dietary Cr supplementation improved immune responses of broilers vaccinated with AI virus, and the inorganic Cr chloride was more effective than the CrPic in increasing the relative weights of lymphoid organs, however, the CrPic was more effective than the inorganic Cr chloride in enhancing the serum antibody titer against AI virus.
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Tatlow D, Poothencheri S, Bhangal R, Tatlow C. Novel method for rapid reversal of drug toxicity: a case report. Clin Exp Pharmacol Physiol 2015; 42:389-93. [PMID: 25586596 DOI: 10.1111/1440-1681.12358] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Revised: 11/25/2014] [Accepted: 01/04/2015] [Indexed: 11/30/2022]
Abstract
Drug toxicity is traditionally treated by reducing the amount of the drug absorbed, enhancing elimination, and providing supportive care. Once the drug has been absorbed, there are few methods that help decrease morbidity and mortality caused by a toxic drug level. Albumin infusion is a new approach that changes that, as it can rapidly reverse a toxic drug level back to a therapeutic level. It is believed with most drugs that the toxic effects are related to the total amount of the free drug. In this method, albumin binds to the free drug and acts as a reservoir or depot from which the drug is slowly released to the free form, thereby limiting the effects of drug toxicity. In this case report, an elderly female patient who experienced phenytoin toxicity was treated with albumin infusion, after which her phenytoin level returned to a therapeutic level with corresponding improvements in her symptoms. Based on our calculations, it was predicted that a small amount of albumin would reverse the patient's toxic symptoms. With this approach, the patient's toxic symptoms improved when free phenytoin levels dropped from 15 to 8 μmol/L. Albumin infusion is a promising new therapy that can rapidly reverse a toxic drug level back to a therapeutic level by binding the free drug to albumin.
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Affiliation(s)
- Dean Tatlow
- Alberta Health Services, Calgary, AB, Canada
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Tatlidil D, Ucuncu M, Akdogan Y. Physiological concentrations of albumin favor drug binding. Phys Chem Chem Phys 2015; 17:22678-85. [DOI: 10.1039/c5cp03583j] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We exploit the direct measurements of spin labeled drugs to study drug binding to/release from protein using EPR spectroscopy.
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Affiliation(s)
- D. Tatlidil
- Materials Science and Engineering Department
- Ízmir Institute of Technology
- Ízmir
- Turkey
| | - M. Ucuncu
- Department of Chemistry
- Ízmir Institute of Technology
- Ízmir
- Turkey
| | - Y. Akdogan
- Materials Science and Engineering Department
- Ízmir Institute of Technology
- Ízmir
- Turkey
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Burian A, Wagner C, Stanek J, Manafi M, Böhmdorfer M, Jäger W, Zeitlinger M. Plasma protein binding may reduce antimicrobial activity by preventing intra-bacterial uptake of antibiotics, for example clindamycin. J Antimicrob Chemother 2010; 66:134-7. [PMID: 21044975 DOI: 10.1093/jac/dkq400] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
OBJECTIVES although plasma protein binding (PPB) is accepted to be an essential factor in reducing antimicrobial activity, little is known about the underlying mechanisms. One possibility includes impaired penetration of an antimicrobial into bacterial cells in the presence of PPB. As a prerequisite for testing this hypothesis an optimized medium displaying high protein binding without impairing bacterial growth had to be identified for our model compound clindamycin. METHODS determination of PPB, bacterial growth and antimicrobial killing was performed in Mueller-Hinton broth (MHB) containing various amounts of human albumin or serum. [(3)H]clindamycin was used to investigate clindamycin penetration into Staphylococcus aureus. RESULTS of all investigated media only MHB(50%serum) and MHB(70%serum) achieved protein binding comparable to pure serum. In contrast, MHB(20%serum) and most media containing only albumin demonstrated considerably lower protein binding. Pure serum resulted in bacterial growth inhibition compared with MHB while MHB(16%albumin) and MHB(50%serum) did not result in significant differences in bacterial count after 24 h. However, in both MHB(16%albumin) and MHB(50%serum) the antimicrobial activity of clindamycin was reduced by >2 log(10) cfu/mL compared with pure MHB. The radioactive signal after administration of [(3)H]clindamycin to S. aureus was significantly decreased in pure serum as well as in MHB(16%albumin) and MHB(50%serum), while no significant difference was observed for MHB(4%albumin) and MHB(20%serum). CONCLUSIONS reduction of the intracellular radioactive signal in the presence of serum proteins correlated both with the degree of protein binding and reduction of antimicrobial activity supporting the hypothesis of impairment of activity by PPB by reducing intra-bacterial antimicrobial concentrations.
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Affiliation(s)
- A Burian
- Department of Clinical Pharmacology, Medical University Vienna, Vienna, Austria
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11
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Xuan H, Hage DS. Evaluation of a hydrazide-linked alpha1-acid glycoprotein chiral stationary phase: separation of R- and S-propranolol. J Sep Sci 2007; 29:1412-22. [PMID: 16894786 DOI: 10.1002/jssc.200600051] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The binding and chiral separation of R- and S-propranolol was investigated on a new type of alpha1-acid glycoprotein (AGP) column. This column was prepared through the controlled and mild oxidation of AGP, followed by the immobilization of this protein to hydrazide-activated silica. The effects of temperature, pH, ionic strength, and organic modifiers on the retention and separation of R- and S-propranolol were investigated on this column. Both the association equilibrium constants and number of binding sites for R/S-propranolol on the AGP column were found to increase with temperature and affect the measured retention factors for these compounds. Regarding the other factors, a change in the organic modifier concentration was found to give the largest change in retention and separation. It was found through these studies that both coulombic and hydrophobic interactions played important roles in determining the retention of R- and S-propranolol on the AGP column. The efficiency and separation impedance of this system were also considered. Under the final optimum conditions identified in this study, it was possible to separate R- and S-propranolol with a resolution of greater than 1.38 in less than 5 min on a 4.1 mm I.D. x 5 cm column.
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Affiliation(s)
- Hai Xuan
- Chemistry Department, University of Nebraska, Lincoln, NE 68599-0304, USA
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12
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Abstract
An analysis of pH-induced changes of drug binding may contribute to the understanding of the mechanisms involved and the clinical relevance. A literature search was performed, and acceptance criteria set up, to select reported data for quantitative evaluation. The relationship between percentage of unbound drug, fu, and pH was analyzed, and the relevance of physicochemical characteristics of the ligand drugs and the importance of hydrogen ion-induced changes in plasma proteins for the pH sensitivity of the binding were evaluated. With all basic and the majority of acidic drugs, fu depended linearly on pH. Basic drugs showed a consistent behavior with fu decreasing with increasing pH. Acidic compounds behaved differently: With some, fu increased, and with others fu decreased, with pH, and with a third group of acids fu was pH independent. Large differences in the pH sensitivity of the plasma protein binding among individual compounds were found. The fu in plasma for some bases and acids increased up to 136% and 95%, respectively, at pH values seen in severe acidemia or alkemia. These changes in fu could be clinically relevant with narrow-therapeutic-range drugs. Physicochemical properties and other characteristics of the ligands affect the pH sensitivity of the interaction with plasma proteins, but there was clear evidence indicating that pH-induced changes in the plasma proteins are also involved in the observed pH-dependent interaction with ligands. It is generally accepted that the unbound, free fraction in whole blood or plasma is an important determinant of the pharmacokinetics and pharmacodynamics of drugs. pH-dependent protein binding and consequent changes in the free fraction have been reported for many drugs. From a basic science point of view, the systematic study of pH-induced perturbations of the drug-protein interaction may provide insight into the mechanism and forces involved in the binding of drugs to plasma proteins. From a clinical viewpoint it may be of interest to know the extent of pH-induced changes in the unbound fraction of drugs under extreme acidemic or alkalemic conditions. Arterial blood pH values compatible with life reportedly range between 6.7 and 8.0. pH values as low as 6.3 have been measured in survivors of drowning accidents. To the best knowledge of the authors, a review and interpretation of pH-associated changes in the protein binding of drugs has not been attempted to date. The goals of this investigation were to (1) review published results of studies that determined the impact of pH changes on the protein binding of drugs in man, (2) select representative data using predetermined criteria, (3) determine relevant factors impacting the pH sensitivity of the drug-protein interaction, and (4) attempt to interpret the results and their clinical relevance.
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Affiliation(s)
- Peter H Hinderling
- Food and Drug Administration, Center for Drug Evaluation and Research, Office of Clinical Pharmacology and Biopharmaceutics, Rockville, Maryland 20852, USA.
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Taheri S, Cogswell LP, Gent A, Strichartz GR. Hydrophobic and ionic factors in the binding of local anesthetics to the major variant of human alpha1-acid glycoprotein. J Pharmacol Exp Ther 2003; 304:71-80. [PMID: 12490577 DOI: 10.1124/jpet.102.042028] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Understanding the interaction of local anesthetics (LAs) with plasma proteins is essential to understanding their systemic pharmacology and toxicology. The molecular determinants of LA binding to the major variant (F1*S) of human alpha1-acid glycoprotein (AGP) were therefore investigated spectrofluorometrically using whole AGP and a novel, F1*S variant-selective probe previously developed in our laboratory. Equilibrium- competitive displacement of this probe by LAs, observed by the recovery of AGP's fluorescence as the quenching probe was displaced from its high-affinity site, was characterized by inhibitory dissociation constants for the various LAs. The importance of electrostatic factors was assessed by examining the pH dependent binding of an ionizable LA, lidocaine, using the quaternary lidocaine derivative QX-314 [N-(2,6-dimethylphenylcarbamoylmethyl) triethylammonium chloride] to control for pH dependent ionization of AGP. Uncharged lidocaine bound with at least 8 times the affinity of protonated lidocaine (K(D) = 4.0 +/- 0.6 microM and >32 microM, respectively). This result is inconsistent with the current model of the AGP-binding site, which depicts a buried pocket having a negatively charged region that interacts with the amino termini of basic drugs. Consistent with the model, however, two sets of structurally homologous LAs (mepivacaine, ropivacaine, bupivacaine, and lidocaine, RAD-240, RAD-241, RAD-242, L-30, W-6603) demonstrated a strong positive correlation between hydrophobicity (measured as the octanol:buffer partition coefficient of the neutral species) and their free energies of dissociation. Given that the tertiary structure of AGP has proven refractory to resolution, these structure-activity studies should contribute to understanding the nature of the binding site on this important protein.
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Affiliation(s)
- Saeed Taheri
- Pain Research Center, Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA
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14
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Johansen AK, Willassen NP, Sager G. Fluorescence studies of beta-adrenergic ligand binding to alpha 1-acid glycoprotein with 1-anilino-8-naphthalene sulfonate, isoprenaline, adrenaline and propranolol. Biochem Pharmacol 1992; 43:725-9. [PMID: 1540225 DOI: 10.1016/0006-2952(92)90236-c] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The present study shows that ANS (1-anilino-8-naphthalene sulfonate), propranolol, isoprenaline, adrenaline and dopamine have common binding sites on AAG (alpha 1-acid glycoprotein). A fluorescence technique was employed to characterize the interaction between the ligands and AAG at 20-22 degrees. The binding of ANS to AAG caused increased fluorescence intensity at emission and excitation wavelengths of 400 and 470 nm. In this situation, propranolol displaced ANS in a concentration-dependent mode with an apparent dissociation constant of 6.2 +/- 0.01 microM, whereas isoprenaline did not reduce the ANS-AAG fluorescence. However, in the presence of AAG, catecholamines caused a marked increase of fluorescence at excitation and emission wavelengths of 250 and 325 nm, respectively. These wavelengths were employed to characterize the binding of isoprenaline, adrenaline and propranolol to AAG. Two subsets of binding sites were demonstrated. The Kd values were 0.87 +/- 0.03 and 25.1 +/- 10.7 microM for ANS, 0.76 +/- 0.09 and 133 +/- 30.4 microM for propranolol, 140 +/- 14 and 2.18 +/- 0.58 mM for isoprenaline, 137 +/- 24 and 14.8 +/- 0.1 mM for adrenaline, respectively. AAG had identical high affinity binding capacity for these ligands (n approximately 1). However, the second class of binding sites showed ligand-dependent binding capacity: n = 1 for ANS, n approximately 10 for propranolol, n approximately 15 for adrenaline, n approximately 20 for isoprenaline, respectively. ANS, propranolol, dopamine and adrenaline caused concentration-dependent inhibition of isoprenaline binding to AAG with apparent dissociation constants of 5.1 +/- 1.8 microM, 6.4 +/- 1.1 microM, 0.57 +/- 0.13 mM and 1.5 +/- 0.46 mM, respectively.
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Affiliation(s)
- A K Johansen
- Department of Pharmacology, University of Tromsø, Norway
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15
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Urien S, Brée F, Testa B, Tillement JP. pH-dependency of basic ligand binding to alpha 1-acid glycoprotein (orosomucoid). Biochem J 1991; 280 ( Pt 1):277-80. [PMID: 1741754 PMCID: PMC1130632 DOI: 10.1042/bj2800277] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The binding interactions of a series of basic ligands with alpha 1-acid glycoprotein (AAG) were examined as a function of pH. The binding to AAG increased with increasing pH, and the binding data were satisfactorily fitted to a model that incorporates the effect of pH and discriminates the association constants of neutral (non-protonated) and protonated forms of ligands. It was shown that ligands in the neutral form have a markedly higher affinity for AAG than the protonated forms, resulting in a concomitant decrease in the pKa of bound ligands. The u.v.-visible difference spectra generated upon binding of a representative ligand to AAG also showed that there was a contribution to the binding arising from the deprotonation of the ligand. It is suggested that all tested ligands bind similarly to AAG and that hydrophobic interactions dominate high-affinity binding to AAG.
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Affiliation(s)
- S Urien
- Laboratoire de Pharmacologie, Faculté de Médecine, Université Paris XII, Créteil, France
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