1
|
Hamad M, Al-Marzooq F, Srinivasulu V, Omar HA, Sulaiman A, Zaher DM, Orive G, Al-Tel TH. Antibacterial Activity of Small Molecules Which Eradicate Methicillin-Resistant Staphylococcus aureus Persisters. Front Microbiol 2022; 13:823394. [PMID: 35178043 PMCID: PMC8846302 DOI: 10.3389/fmicb.2022.823394] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2021] [Accepted: 01/11/2022] [Indexed: 11/13/2022] Open
Abstract
The serious challenge posed by multidrug-resistant bacterial infections with concomitant treatment failure and high mortality rates presents an urgent threat to the global health. We herein report the discovery of a new class of potent antimicrobial compounds that are highly effective against Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA). The compounds were efficiently synthesized in one-pot employing a cascade of Groebke-Blackburn-Bienaymé and aza-Michael addition reactions. Phenotypic screening of the pilot library against various bacterial species including methicillin-sensitive and MRSA strains, has identified potent chemotypes with minimal inhibitory concentrations (MIC) of 3.125-6.25 μg/ml. The most potent compounds were fast-acting at eradicating exponentially growing MRSA, with killing achieved after 30 min of exposure to the compounds. They were also able to kill MRSA persister cells which are tolerant to most available medications. Microscopic analysis using fluorescence microscope and atomic force microscope indicate that these compounds lead to disruption of bacterial cell envelopes. Most notably, bacterial resistance toward these compounds was not observed after 20 serial passages in stark contrast to the significant resistance developed rapidly upon exposure to a clinically relevant antibiotic. Furthermore, the compounds did not induce significant hemolysis to human red blood cells. In vivo safety studies revealed a high safety profile of these motifs. These small molecules hold a promise for further studies and development as new antibacterial agents against MRSA infections.
Collapse
Affiliation(s)
- Mohamad Hamad
- Sharjah Institute for Medical Research, University of Sharjah, Sharjah, United Arab Emirates.,College of Health Sciences, University of Sharjah, Sharjah, United Arab Emirates
| | - Farah Al-Marzooq
- Sharjah Institute for Medical Research, University of Sharjah, Sharjah, United Arab Emirates.,College of Medicine and Health Sciences, UAE University, Al Ain, United Arab Emirates
| | - Vunnam Srinivasulu
- Sharjah Institute for Medical Research, University of Sharjah, Sharjah, United Arab Emirates
| | - Hany A Omar
- Sharjah Institute for Medical Research, University of Sharjah, Sharjah, United Arab Emirates.,College of Pharmacy, University of Sharjah, Sharjah, United Arab Emirates
| | - Ashna Sulaiman
- Sharjah Institute for Medical Research, University of Sharjah, Sharjah, United Arab Emirates
| | - Dana M Zaher
- Sharjah Institute for Medical Research, University of Sharjah, Sharjah, United Arab Emirates
| | - Gorka Orive
- NanoBioCel Group, Laboratory of Pharmaceutics, School of Pharmacy, University of the Basque Country (UPV/EHU), Bilbao, Spain
| | - Taleb H Al-Tel
- Sharjah Institute for Medical Research, University of Sharjah, Sharjah, United Arab Emirates.,College of Pharmacy, University of Sharjah, Sharjah, United Arab Emirates
| |
Collapse
|
2
|
Gao J, Wang Y, Lyu B, Chen J, Chen G. Component Identification of Phenolic Acids in Cell Suspension Cultures of Saussureainvolucrata and Its Mechanism of Anti-Hepatoma Revealed by TMT Quantitative Proteomics. Foods 2021; 10:foods10102466. [PMID: 34681515 PMCID: PMC8535732 DOI: 10.3390/foods10102466] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 10/11/2021] [Accepted: 10/12/2021] [Indexed: 12/13/2022] Open
Abstract
Saussurea involucrata (S. involucrata) had been reported to have anti-hepatoma function. However, the mechanism is complex and unclear. To evaluate the anti-hepatoma mechanism of S. involucrata comprehensively and make a theoretical basis for the mechanical verification of later research, we carried out this work. In this study, the total phenolic acids from S. involucrata determined by a cell suspension culture (ESPI) was mainly composed of 4,5-dicaffeoylquinic acid, according to the LC-MS analysis. BALB/c nude female mice were injected with HepG2 cells to establish an animal model of liver tumor before being divided into a control group, a low-dose group, a middle-dose group, a high-dose group, and a DDP group. Subsequently, EPSI was used as the intervention drug for mice. Biochemical indicators and differences in protein expression determined by TMT quantitative proteomics were used to resolve the mechanism after the low- (100 mg/kg), middle- (200 mg/kg), and high-dose (400 mg/kg) interventions for 24 days. The results showed that EPSI can not only limit the growth of HepG2 cells in vitro, but also can inhibit liver tumors significantly with no toxicity at high doses in vivo. Proteomics analysis revealed that the upregulated differentially expressed proteins (DE proteins) in the high-dose group were over three times that in the control group. ESPI affected the pathways significantly associated with the protein metabolic process, metabolic process, catalytic activity, hydrolase activity, proteolysis, endopeptidase activity, serine-type endopeptidase activity, etc. The treatment group showed significant differences in the pathways associated with the renin-angiotensin system, hematopoietic cell lineage, etc. In conclusion, ESPI has a significant anti-hepatoma effect and the potential mechanism was revealed.
Collapse
Affiliation(s)
- Junpeng Gao
- College of Life Science, Jilin Agricultural University, Changchun 130118, China;
| | - Yi Wang
- College of Food Science and Engineering, Jilin Agricultural University, Changchun 130118, China; (Y.W.); (B.L.); (J.C.)
| | - Bo Lyu
- College of Food Science and Engineering, Jilin Agricultural University, Changchun 130118, China; (Y.W.); (B.L.); (J.C.)
- College of Food Science, Northeast Agricultural University, Harbin 150030, China
| | - Jian Chen
- College of Food Science and Engineering, Jilin Agricultural University, Changchun 130118, China; (Y.W.); (B.L.); (J.C.)
| | - Guang Chen
- College of Life Science, Jilin Agricultural University, Changchun 130118, China;
- Correspondence:
| |
Collapse
|
3
|
Zaher DM, Ramadan WS, El-Awady R, Omar HA, Hersi F, Srinivasulu V, Hachim IY, Al-Marzooq FI, Vazhappilly CG, Merali S, Merali C, Soares NC, Schilf P, Ibrahim SM, Al-Tel TH. A Novel Benzopyrane Derivative Targeting Cancer Cell Metabolic and Survival Pathways. Cancers (Basel) 2021; 13:cancers13112840. [PMID: 34200264 PMCID: PMC8201054 DOI: 10.3390/cancers13112840] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Revised: 06/01/2021] [Accepted: 06/02/2021] [Indexed: 02/03/2023] Open
Abstract
(1) Background: Today, the discovery of novel anticancer agents with multitarget effects and high safety margins represents a high challenge. Drug discovery efforts indicated that benzopyrane scaffolds possess a wide range of pharmacological activities. This spurs on building a skeletally diverse library of benzopyranes to identify an anticancer lead drug candidate. Here, we aim to characterize the anticancer effect of a novel benzopyrane derivative, aiming to develop a promising clinical anticancer candidate. (2) Methods: The anticancer effect of SIMR1281 against a panel of cancer cell lines was tested. In vitro assays were performed to determine the effect of SIMR1281 on GSHR, TrxR, mitochondrial metabolism, DNA damage, cell cycle progression, and the induction of apoptosis. Additionally, SIMR1281 was evaluated in vivo for its safety and in a xenograft mice model. (3) Results: SIMR1281 strongly inhibits GSHR while it moderately inhibits TrxR and modulates the mitochondrial metabolism. SIMR1281 inhibits the cell proliferation of various cancers. The antiproliferative activity of SIMR1281 was mediated through the induction of DNA damage, perturbations in the cell cycle, and the inactivation of Ras/ERK and PI3K/Akt pathways. Furthermore, SIMR1281 induced apoptosis and attenuated cell survival machinery. In addition, SIMR1281 reduced the tumor volume in a xenograft model while maintaining a high in vivo safety profile at a high dose. (4) Conclusions: Our findings demonstrate the anticancer multitarget effect of SIMR1281, including the dual inhibition of glutathione and thioredoxin reductases. These findings support the development of SIMR1281 in preclinical and clinical settings, as it represents a potential lead compound for the treatment of cancer.
Collapse
Affiliation(s)
- Dana M. Zaher
- Sharjah Institute for Medical Researches, University of Sharjah, Sharjah 27272, United Arab Emirates; (D.M.Z.); (W.S.R.); (R.E.-A.); (H.A.O.); (F.H.); (V.S.); (I.Y.H.); (F.I.A.-M.); (C.G.V.); (N.C.S.); (S.M.I.)
- College of Medicine, University of Sharjah, Sharjah 27272, United Arab Emirates
| | - Wafaa S. Ramadan
- Sharjah Institute for Medical Researches, University of Sharjah, Sharjah 27272, United Arab Emirates; (D.M.Z.); (W.S.R.); (R.E.-A.); (H.A.O.); (F.H.); (V.S.); (I.Y.H.); (F.I.A.-M.); (C.G.V.); (N.C.S.); (S.M.I.)
- College of Medicine, University of Sharjah, Sharjah 27272, United Arab Emirates
| | - Raafat El-Awady
- Sharjah Institute for Medical Researches, University of Sharjah, Sharjah 27272, United Arab Emirates; (D.M.Z.); (W.S.R.); (R.E.-A.); (H.A.O.); (F.H.); (V.S.); (I.Y.H.); (F.I.A.-M.); (C.G.V.); (N.C.S.); (S.M.I.)
- College of Pharmacy, University of Sharjah, Sharjah 27272, United Arab Emirates
| | - Hany A. Omar
- Sharjah Institute for Medical Researches, University of Sharjah, Sharjah 27272, United Arab Emirates; (D.M.Z.); (W.S.R.); (R.E.-A.); (H.A.O.); (F.H.); (V.S.); (I.Y.H.); (F.I.A.-M.); (C.G.V.); (N.C.S.); (S.M.I.)
- College of Pharmacy, University of Sharjah, Sharjah 27272, United Arab Emirates
- Faculty of Pharmacy, Beni-Suef University, Beni-Suef 62511, Egypt
| | - Fatema Hersi
- Sharjah Institute for Medical Researches, University of Sharjah, Sharjah 27272, United Arab Emirates; (D.M.Z.); (W.S.R.); (R.E.-A.); (H.A.O.); (F.H.); (V.S.); (I.Y.H.); (F.I.A.-M.); (C.G.V.); (N.C.S.); (S.M.I.)
- College of Medicine, University of Sharjah, Sharjah 27272, United Arab Emirates
| | - Vunnam Srinivasulu
- Sharjah Institute for Medical Researches, University of Sharjah, Sharjah 27272, United Arab Emirates; (D.M.Z.); (W.S.R.); (R.E.-A.); (H.A.O.); (F.H.); (V.S.); (I.Y.H.); (F.I.A.-M.); (C.G.V.); (N.C.S.); (S.M.I.)
| | - Ibrahim Y. Hachim
- Sharjah Institute for Medical Researches, University of Sharjah, Sharjah 27272, United Arab Emirates; (D.M.Z.); (W.S.R.); (R.E.-A.); (H.A.O.); (F.H.); (V.S.); (I.Y.H.); (F.I.A.-M.); (C.G.V.); (N.C.S.); (S.M.I.)
- College of Medicine, University of Sharjah, Sharjah 27272, United Arab Emirates
| | - Farah I. Al-Marzooq
- Sharjah Institute for Medical Researches, University of Sharjah, Sharjah 27272, United Arab Emirates; (D.M.Z.); (W.S.R.); (R.E.-A.); (H.A.O.); (F.H.); (V.S.); (I.Y.H.); (F.I.A.-M.); (C.G.V.); (N.C.S.); (S.M.I.)
- Department of Medical Microbiology and Immunology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain 15551, United Arab Emirates
| | - Cijo G. Vazhappilly
- Sharjah Institute for Medical Researches, University of Sharjah, Sharjah 27272, United Arab Emirates; (D.M.Z.); (W.S.R.); (R.E.-A.); (H.A.O.); (F.H.); (V.S.); (I.Y.H.); (F.I.A.-M.); (C.G.V.); (N.C.S.); (S.M.I.)
- School of Arts and Sciences, American University of Ras Al Khaimah, P.O. Box 10021, Ras Al Khaimah 10021, United Arab Emirates
| | - Salim Merali
- School of Pharmacy, Temple University, 3307 N Broad Street, Room 552, Philadelphia, PA 19140, USA; (S.M.); (C.M.)
| | - Carmen Merali
- School of Pharmacy, Temple University, 3307 N Broad Street, Room 552, Philadelphia, PA 19140, USA; (S.M.); (C.M.)
| | - Nelson C. Soares
- Sharjah Institute for Medical Researches, University of Sharjah, Sharjah 27272, United Arab Emirates; (D.M.Z.); (W.S.R.); (R.E.-A.); (H.A.O.); (F.H.); (V.S.); (I.Y.H.); (F.I.A.-M.); (C.G.V.); (N.C.S.); (S.M.I.)
- College of Pharmacy, University of Sharjah, Sharjah 27272, United Arab Emirates
| | - Paul Schilf
- Lübeck Institute of Experimental Dermatology, University of Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany;
| | - Saleh M. Ibrahim
- Sharjah Institute for Medical Researches, University of Sharjah, Sharjah 27272, United Arab Emirates; (D.M.Z.); (W.S.R.); (R.E.-A.); (H.A.O.); (F.H.); (V.S.); (I.Y.H.); (F.I.A.-M.); (C.G.V.); (N.C.S.); (S.M.I.)
- College of Medicine, University of Sharjah, Sharjah 27272, United Arab Emirates
- Lübeck Institute of Experimental Dermatology, University of Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany;
| | - Taleb H. Al-Tel
- Sharjah Institute for Medical Researches, University of Sharjah, Sharjah 27272, United Arab Emirates; (D.M.Z.); (W.S.R.); (R.E.-A.); (H.A.O.); (F.H.); (V.S.); (I.Y.H.); (F.I.A.-M.); (C.G.V.); (N.C.S.); (S.M.I.)
- College of Pharmacy, University of Sharjah, Sharjah 27272, United Arab Emirates
- Correspondence: ; Tel.: +971-6505-7417
| |
Collapse
|
4
|
Shaik AS, Shaik AP, Bammidi VK, Al Faraj A. Effect of polyethylene glycol surface charge functionalization of SWCNT on the in vitro and in vivo nanotoxicity and biodistribution monitored noninvasively using MRI. Toxicol Mech Methods 2019; 29:233-243. [PMID: 30480460 DOI: 10.1080/15376516.2018.1540674] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The current study evaluated in vitro and in vivo toxicity of carboxyl or amine polyethylene glycol (PEG) surface functionalization of single-walled carbon nanotubes (SWCNTs). Assessments of cytotoxicity, genotoxicity, immunotoxicity, and oxidative stress were performed in vitro and in vivo (in a 1-month follow-up study). The SWCNT biodistribution was investigated using noninvasive magnetic resonance imaging (MRI). Results confirmed the enhanced biocompatibility of PEG-functionalized SWCNTs compared to non-functionalized materials with significant decreases (p < 0.05) in the percentage of cell viability and increases in ROS generation, mitochondrial membrane potential, cell apoptosis, oxidative stress generation, and oxidative DNA damage in vitro. PEG-functionalized SWCNTs with amine terminals were found to induce prominent increases in ROS generation, mitochondrial membrane potential, and oxidative stress compared to carboxy functionalization. No significant difference in the biodistribution of either functionalized SWCNTs was observed in MRI. In vivo assessments revealed a statistically significant increase (p < 0.05) in oxidative stress as early as 24 h in serum and liver; however, all values normalized at 2 weeks' investigation time point. DNA damage was minimal with either PEG-COOH or PEG-NH2 functionalized SWCNTs after 2 weeks' exposure. The negatively charged SWCNTs caused lesser DNA damage compared to positively charged samples. Carboxy-functionalized SWCNTs did not cause substantial changes in inflammatory mediators and were found to be significantly safer than non-functionalized SWCNTs and may pave the way for novel biomedical applications in cancer diagnosis and therapy.
Collapse
Affiliation(s)
- Asma Sultana Shaik
- a Prince Naif Health Research Center , King Saud University , Riyadh , Saudi Arabia
| | - Abjal Pasha Shaik
- b Department of Clinical Lab Sciences , College of Applied Medical Sciences, King Saud University , Riyadh , Saudi Arabia
| | - Vamsee K Bammidi
- c The Unicare Group, Burton-on-Trent , Staffordshire , United Kingdom
| | - Achraf Al Faraj
- d Department of Radiologic Sciences, Faculty of Health Science , American University of Science and Technology , Beirut , Lebanon
| |
Collapse
|
5
|
Parasuraman S, Raveendran R, Rajesh NG, Nandhakumar S. Sub-chronic toxicological evaluation of cleistanthin A and cleistanthin B from the leaves of Cleistanthus collinus (Roxb.). Toxicol Rep 2014; 1:596-611. [PMID: 28962273 PMCID: PMC5598356 DOI: 10.1016/j.toxrep.2014.08.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 08/04/2014] [Accepted: 08/11/2014] [Indexed: 10/31/2022] Open
Abstract
OBJECTIVE To investigate the toxicological effects of cleistanthin A and cleistanthin B using sub-chronic toxicity testing in rodents. METHOD Cleistanthins A and B were isolated from the leaves of Cleistanthus collinus. Both the compounds were administered orally for 90 days at the concentration of 12.5, 25 and 50 mg/kg, and the effects on blood pressure, biochemical parameters and histology were assessed. The dose for sub-chronic toxicology was determined by fixed dose method according to OECD guidelines. RESULT Sub-chronic toxicity study of cleistanthins A and B spanning over 90 days at the dose levels of 12.5, 25 and 50 mg/kg (once daily, per oral) revealed a significant dose dependant toxic effect in lungs. The compounds did not have any effect on the growth of the rats. The food and water intake of the animals were also not affected by both cleistanthins A and B. Both the compounds did not have any significant effect on liver and renal markers. The histopathological analysis of both cleistanthins A and B showed dose dependent morphological changes in the brain, heart, lung, liver and kidney. When compared to cleistanthin A, cleistanthin B had more toxic effect in Wistar rats. Both the compounds have produced a dose dependent increase of corpora amylacea in brain and induced acute tubular necrosis in kidneys. In addition, cleistanthin B caused spotty necrosis of liver in higher doses. CONCLUSION The present study concludes that both cleistanthin A and cleistanthin B exert severe toxic effects on lungs, brain, liver, heart and kidneys. They do not cause any significant pathological change in the reproductive system; neither do they induce neurodegenerative changes in brain. When compared to cleistanthin A, cleistanthin B is more toxic in rats.
Collapse
Affiliation(s)
- Subramani Parasuraman
- Department of Pharmacology, Jawaharlal Institute of Postgraduate Medical Education & Research (JIPMER), Puducherry 605006, India.,Unit of Pharmacology, Faculty of Pharmacy, AIMST University, Bedong-Semeling Road, Bedong 08100, Kedah, Malaysia
| | - Ramasamy Raveendran
- Department of Pharmacology, Jawaharlal Institute of Postgraduate Medical Education & Research (JIPMER), Puducherry 605006, India
| | - Nachiappa Ganesh Rajesh
- Department of Pathology, Jawaharlal Institute of Postgraduate Medical Education & Research (JIPMER), Puducherry 605006, India
| | - Subbiah Nandhakumar
- Department of Anatomy, Jawaharlal Institute of Postgraduate Medical Education & Research (JIPMER), Puducherry 605006, India
| |
Collapse
|
6
|
Glycyrol suppresses collagen-induced arthritis by regulating autoimmune and inflammatory responses. PLoS One 2014; 9:e98137. [PMID: 25036817 PMCID: PMC4103760 DOI: 10.1371/journal.pone.0098137] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Accepted: 04/29/2014] [Indexed: 01/19/2023] Open
Abstract
Glycyrol is a natural compound extracted from Glycyrrhiza uralensis, first reported by us to be a new immunosuppressant. Here, we demonstrate its beneficial effect in collagen-induced arthritis (CIA) in mice, a model for rheumatoid arthritis (RA) in man, and we document the underlying mechanisms. Peroral administration of glycyrol significantly reduced clinical scores, alleviated cartilage and bone erosion and reduced levels of serum inflammatory cytokines. Glycyrol also decreased delayed-type hypersensitivity, improved carbon clearance and reduced acetic acid-induced capillary permeability. Furthermore, glycyrol decreased NF-κB and NFAT transcriptional activities and inhibited IL-2 expression. The therapeutic effect of glycyrol was associated with down-regulation of both autoimmune and inflammatory reactions. In addition, we demonstrated that glycyrol has minimal acute toxicity in mice. Therefore, we propose that glycyrol may hold promise for future treatment of RA.
Collapse
|
7
|
Abstract
Calcineurin (CN), a unique protein phosphatase, plays an important role in immune regulation. In this study we used CN as a target enzyme to investigate the immunosuppressive properties of a series of natural compounds from Garcinia mangostana L., and discovered an active compound, isogarcinol. Enzymatic assays showed that isogarcinol inhibited CN in a dose-dependent manner. At concentrations resulting in relatively low cytotoxicity isogarcinol significantly inhibited proliferation of murine spleen T-lymphocytes induced by concanavalin A (ConA) and the mixed lymphocyte reaction (MLR). In addition, it performed much better in acute toxicity tests and via oral administration in mice than cyclosporin A (CsA), with few adverse reactions and low toxicity in experimental animals. Oral administration of isogarcinol in mice resulted in a dose-dependent decrease in delayed type hypersensitivity (DTH) and prolonged graft survival in allogeneic skin transplantation. These findings suggest that isogarcinol could serve as a new oral immunomodulatory drug for preventing transplant rejection, and for long-term medication in autoimmune diseases.
Collapse
|
8
|
Abstract
Toxicity testing of new compounds is essential for drug development process. The preclinical toxicity testing on various biological systems reveals the species-, organ- and dose- specific toxic effects of an investigational product. The toxicity of substances can be observed by (a) studying the accidental exposures to a substance (b) in vitro studies using cells/ cell lines (c) in vivo exposure on experimental animals. This review mainly focuses on the various experimental animal models and methods used for toxicity testing of substances. The pre-clinical toxicity testing helps to calculate "No Observed Adverse Effect Level" which is needed to initiate the clinical evaluation of investigational products.
Collapse
Affiliation(s)
- S Parasuraman
- Department of Pharmacology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India
| |
Collapse
|
9
|
Abstract
The fixed-dose procedure (FDP) was introduced as OECD Test Guideline 420 in 1992, as an alternative to the conventional median lethal dose (LD50) test for the assessment of acute oral toxicity (OECD Test Guideline 401). The FDP uses fewer animals and causes less suffering than the conventional test, while providing information on the acute toxicity to allow substances to be ranked according to the EU hazard classification system. Recently the FDP has been revised, with the aim of providing further reductions and refinements, and classification according to the criteria of the Globally Harmonized Hazard Classification and Labelling scheme (GHS). This paper describes the revised FDP and analyses its properties, as determined by a statistical modelling approach. The analysis shows that the revised FDP classifies substances for acute oral toxicity generally in the same, or a more stringent, hazard class as that based on the LD50 value, according to either the GHS or the EU classification scheme. The likelihood of achieving the same classification is greatest for substances with a steep dose-response curve and median toxic dose (TD50) close to the LD50. The revised FDP usually requires five or six animals with two or fewer dying as a result of treatment in most cases.
Collapse
Affiliation(s)
- N Stalla
- Medical and Pharmaceutical Statistics Research Unit, The University of Reading, UK.
| | | | | |
Collapse
|
10
|
Abstract
The purposes of acute toxicity testing are to obtain information on the biologic activity of a chemical and gain insight into its mechanism of action. The information on acute systemic toxicity generated by the test is used in hazard identification and risk management in the context of production, handling, and use of chemicals. The LD50 value, defined as the statistically derived dose that, when administered in an acute toxicity test, is expected to cause death in 50% of the treated animals in a given period, is currently the basis for toxicologic classification of chemicals. For a classical LD50 study, laboratory mice and rats are the species typically selected. Often both sexes must be used for regulatory purposes. When oral administration is combined with parenteral, information on the bioavailability of the tested compound is obtained. The result of the extensive discussions on the significance of the LD50 value and the concomitant development of alternative procedures is that authorities today do not usually demand classical LD50 tests involving a large number of animals. The limit test, the fixed-dose procedure, the toxic class method, and the up-and-down methods all represent simplified alternatives using only a few animals. Efforts have also been made to develop in vitro systems; e.g., it has been suggested that acute systemic toxicity can be broken down into a number of biokinetic, cellular, and molecular elements, each of which can be identified and quantified in appropriate models. The various elements may then be used in different combinations to model large numbers of toxic events to predict hazard and classify compounds.
Collapse
Affiliation(s)
- E Walum
- Cell and Molecular Biology, Research Department, Pharmacia & Upjohn, Stockholm, Sweden.
| |
Collapse
|
11
|
Stallard N, Whitehead A. Improving the Efficiency of Fixed-Dose Procedures for the Assessment of Acute Oral Toxicity. ACTA ACUST UNITED AC 1997. [DOI: 10.1177/009286159703100208] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
12
|
Stallard N, Whitehead A. Reply to the letter of Diener and Schlede. Hum Exp Toxicol 1996. [DOI: 10.1177/096032719601501012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
| | - Anne Whitehead
- MPS Research Unit The University of Reading Earley Gate, Whiteknights PO Box 240, Reading RG6 6FN UK
| |
Collapse
|
13
|
Stallard N, Whitehead A. The fixed-dose procedure and the acute-toxic-class method: a mathematical comparison. Hum Exp Toxicol 1995; 14:974-90. [PMID: 8962748 DOI: 10.1177/096032719501401206] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The fixed-dose procedure (FDP), proposed by the British Toxicology Society, and the acute-toxic-class (ATC) method, proposed by the German Federal Health Authority, provide alternatives to the LD50 test for classifying substances by their acute oral toxicity. This paper presents a mathematical model that is used to compare the two procedures in terms of their classification properties and the required numbers of animals. It is found that the classification properties of the procedures depend on the dose levels used, the number of animals tested per dose and the criteria that are used to decide whether testing should continue at a higher or lower dose. For substances with steep dose-response curves, the most likely classification is determined chiefly by the choice of the dose levels whilst the number of animals and continuation criteria used are increasingly important for substances with dose-response curves with a smaller slope. The use of toxicity as a possible endpoint as in the FDP and the use of a two-stage testing procedure at each dose as in the ATC method are both found to reduce the expected numbers of animals required with little effect on the classification properties. On the strength of these findings it is indicated that a new procedure combining the dose levels and testing approach of the ATC method with the inclusion of toxicity as an endpoint as in the FDP would be more efficient than either the FDP or the ATC method.
Collapse
Affiliation(s)
- N Stallard
- Department of Applied Statistics, University of Reading, UK
| | | |
Collapse
|