1
|
Krishna MT, Bhogal R, Ng BY, Kildonaviciute K, Jani YH, Williams I, Sandoe JAT, Pollard R, Jones N, Dunsmure L, Powell N, Hullur C, Balaji A, Moriarty C, Jackson B, Warner A, Daniels R, West R, Thomas C, Misbah SA, Savic L. A multicentre observational study to investigate feasibility of a direct oral penicillin challenge in de-labelling 'low risk' patients with penicillin allergy by non-allergy healthcare professionals (SPACE study): Implications for healthcare systems. J Infect 2024; 88:106116. [PMID: 38331329 PMCID: PMC10961940 DOI: 10.1016/j.jinf.2024.01.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 01/17/2024] [Accepted: 01/30/2024] [Indexed: 02/10/2024]
Abstract
OBJECTIVE The huge burden of inaccurate penicillin allergy labels (PALs) is an important driver of antimicrobial resistance. This is magnified by insufficient allergy specialists and lack of 'point-of-care' tests. We investigated the feasibility of non-allergy healthcare professionals (HCPs) delivering direct oral penicillin challenges (DPCs) for penicillin allergy de-labelling. METHODS This prospective observational study was conducted in three hospitals in England across three settings (acute medical, pre-surgical and haematology-oncology). Patients with a PAL were screened and stratified as low risk/high risk. Low risk patients (non-immune mediated symptoms, benign rash, tolerated amoxicillin since and family history) underwent a DPC. RESULTS N = 2257 PALs were screened, 1054 were eligible; 643 were approached, 373 declined, 270 consented and 259 risk stratified (low risk = 155; high risk = 104). One hundred and twenty-six low risk patients underwent DPC, 122 (96.8%) were de-labelled with no serious allergic reactions. Conversion rate from screening-to-consent was 12% [3.3% and 17.9% in acute and elective settings respectively; odds ratios for consent were 3.42 (p < 0.001) and 5.53 (p < 0.001) in haematology-oncology and pre-surgical setting respectively. Common reasons for failure to progress in the study included difficulty in reaching patients, clinical instability/medical reasons, lacking capacity to consent and psychological factors. INTERPRETATION DPCs can be delivered by non-allergy HCPs. A high proportion of patients with PALs did not progress in the study pathway. Strategies to deliver DPC at optimal points of the care pathway are needed to enhance uptake. Elective settings offer greater opportunities than acute settings for DPC. The safety and simplicity of DPCs lends itself to adoption by healthcare systems beyond the UK, including in resource-limited settings.
Collapse
Affiliation(s)
- Mamidipudi Thirumala Krishna
- Institute of Immunology and Immunotherapy, University of Birmingham and Department of Allergy and Immunology, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK.
| | - Rashmeet Bhogal
- Department of Pharmacy, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
| | - Bee Yean Ng
- Department of Pharmacy, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | | | - Yogini H Jani
- Centre for Medicines Optimisation Research and Education, University College London Hospitals NHS Foundation Trust and UCL School of Pharmacy, London, UK
| | - Iestyn Williams
- Health Services Management Centre, University of Birmingham, Birmingham, UK
| | - Jonathan A T Sandoe
- Healthcare Associated Infection Group, Leeds Institute of Medical Research, University of Leeds and Leeds Teaching Hospitals NHS Trust, Leeds, UK
| | - Rachel Pollard
- Department of Anaesthesia, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Nicola Jones
- Department of Infectious Diseases, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Louise Dunsmure
- Department of Pharmacy, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Neil Powell
- Department of Pharmacy, Royal Cornwall Hospitals NHS Trust, Truro, UK
| | - Chidanand Hullur
- Department of Anaesthesia, Birmingham Heartlands Hospital, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
| | - Ariyur Balaji
- Acute Medicine Unit, Birmingham Heartlands Hospital, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
| | - Catherine Moriarty
- Theatres and Anaesthetics Research Team, St James' University Hospital, Leeds Teaching Hospitals, Leeds, UK
| | - Beverley Jackson
- Theatres and Anaesthetics Research Team, St James' University Hospital, Leeds Teaching Hospitals, Leeds, UK
| | | | | | - Robert West
- Healthcare Associated Infection Group, Leeds Institute of Medical Research, University of Leeds and Leeds Teaching Hospitals NHS Trust, Leeds, UK
| | - Caroline Thomas
- Department of Anaesthesia, St James' University Hospital, Leeds Teaching Hospitals NHS Trust, Leeds, UK
| | - Siraj A Misbah
- Department of Clinical Immunology, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Louise Savic
- Department of Anaesthesia, St James' University Hospital, Leeds Teaching Hospitals NHS Trust, Leeds, UK
| |
Collapse
|
2
|
Bhogal R, Powell N, Elkhalifa S. Management of BAME patients with a history of penicillin allergy: barriers to best practice and strategies to overcome these. Infect Prev Pract 2023; 5:100319. [PMID: 38107244 PMCID: PMC10724474 DOI: 10.1016/j.infpip.2023.100319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 08/01/2023] [Indexed: 12/19/2023] Open
Affiliation(s)
- Rashmeet Bhogal
- The School of Pharmacy and Institute of Clinical Sciences, University of Birmingham, Birmingham United Kingdom
| | - Neil Powell
- Pharmacy Department, Royal Cornwall Hospital Trust, Truro, UK
| | - Shuayb Elkhalifa
- Allergy and Clinical Immunology Department, Respiratory Institute, Cleveland Clinic Abu Dhabi, Abu Dhabi, United Arab Emirates
- Centre for Musculoskeletal Research, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
| |
Collapse
|
3
|
Limbu S, Purba T, Bhogal R, O’Neill C, Paus R. 584 Dandruff is associated with perturbations of hair follicle immune privilege, and the infundibular and epidermal immune microenvironment. J Invest Dermatol 2022. [DOI: 10.1016/j.jid.2022.09.600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
4
|
Bermingham WH, Bhogal R, Nagarajan S, Mutlu L, El-Shabrawy RM, Madhan R, Maheshwari UM, Murali M, Kudagammana ST, Shrestha R, Sumantri S, Christopher DJ, Mahesh PA, Dedicoat M, Krishna MT. 'Practical management of suspected hypersensitivity reactions to anti-tuberculosis drugs.'. Clin Exp Allergy 2021; 52:375-386. [PMID: 34939251 DOI: 10.1111/cea.14084] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 12/07/2021] [Accepted: 12/09/2022] [Indexed: 11/28/2022]
Abstract
Tuberculosis (TB) is the commonest cause of death by a single infectious agent globally and ranks amongst the top ten causes of global mortality. The incidence of TB is highest in Low-Middle Income countries (LMICs). Prompt institution of, and compliance with, therapy are cornerstones for a favourable outcome in TB and to mitigate the risk of multiple drug resistant (MDR)-TB, which is challenging to treat. There is some evidence that adverse drug reactions (ADRs) and hypersensitivity reactions (HSRs) to anti-TB drugs occur in over 60% and 3-4% of patients respectively. Both ADRs and HSRs represent significant barriers to treatment adherence and are recognised risk factors for MDR-TB. HSRs to anti-TB drugs are usually cutaneous and benign, occur within few weeks after commencement of therapy and are likely to be T-cell mediated. Severe and systemic T-cell mediated HSRs and IgE mediated anaphylaxis to anti-TB drugs are relatively rare, but important to recognise and treat promptly. T-cell mediated HSRs are more frequent amongst patients with co-existing HIV infection. Some patients develop multiple sensitisation to anti-TB drugs. Whilst skin tests, patch tests and in vitro diagnostics have been used in the investigation of HSRs to anti-TB drugs, their predictive value is not established, they are onerous, require specialist input of an allergist and are resource-dependent. This is compounded by the global, unmet demand for allergy specialists, particularly in low income countries (LICs) / LMICs and now the challenging circumstances of the SARS-CoV-2 pandemic. This narrative review provides a critical analysis of the limited published evidence on this topic and proposes a cautious and pragmatic approach to optimise and standardise the management of HSRs to anti-TB drugs. This includes clinical risk stratification and a dual strategy involving sequential re-challenge and rapid drug desensitisation. Furthermore, a concerted international effort is needed to generate real-time data on ADRs, HSRs, safety and clinical outcomes of these interventions.
Collapse
Affiliation(s)
- W H Bermingham
- Department of Allergy & Immunology, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
| | - R Bhogal
- Department of Pharmacy, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
| | - S Nagarajan
- Department of Allergy and Immunology, Mallige Hospital, Bangalore, India
| | - L Mutlu
- Department of Allergy & Immunology, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
| | | | - R Madhan
- Department of Pharmacy Practice, JSS College of Pharmacy, JSS AHER, Mysuru, India
| | - U M Maheshwari
- Department of Respiratory Medicine, St Johns Medical College, Bengaluru, India
| | - M Murali
- Division of Allergy and Clinical Immunology, Department of Medicine, Massachusetts General hospital, Boston, MA, 02114, USA
| | - S T Kudagammana
- Faculty of Medicine, University of Peradeniya, Honorary Consultant Paediatrician, Teaching hospital, Peradeniya, Sri Lanka
| | - R Shrestha
- Departments of Clinical Pharmacology, Dhulikhel Hospital, Kathmandu University Hospital, Nepal
| | - S Sumantri
- Department of Internal Medicine, Universitas Pelita Harapan, Siloam Academic Hospital Lippo Village, Tangerang, Banten, Indonesia
| | - D J Christopher
- Department of Pulmonary Medicine, Christian Medical College, Vellore, India
| | - P A Mahesh
- Department of Respiratory Medicine, JSS Medical College, JSSAHER, Mysuru, India
| | - M Dedicoat
- Department of Infectious Diseases and Tropical Medicine, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
| | - M T Krishna
- Department of Allergy & Immunology, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK.,Institute of Immunology and Immunotherapy, University of Birmingham, UK
| |
Collapse
|
5
|
Bhogal R, Hussain A, Savic L, Misbah SA, Balaji A, Hullur C, Marriott JF, Krishna MT. Heterogeneity in direct oral penicillin challenge protocols in penicillin allergy de-labelling. Infect Prev Pract 2021; 4:100185. [PMID: 36090525 PMCID: PMC9452040 DOI: 10.1016/j.infpip.2021.100185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 11/09/2021] [Indexed: 10/28/2022] Open
|
6
|
Bhogal R, Hussain A, Balaji A, Bermingham WH, Marriott JF, Krishna MT. The role of a clinical pharmacist in spurious Penicillin allergy: a narrative review. Int J Clin Pharm 2021; 43:461-475. [PMID: 33439428 DOI: 10.1007/s11096-020-01226-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 12/30/2020] [Indexed: 12/31/2022]
Abstract
Background A label of penicillin allergy is held by 6-10% of the general population and 15-20% of inpatients. > 90% of these labels are found to be spurious after formal allergy assessment. Carrying an unnecessary label of penicillin allergy is not benign. Such patients may receive second line, more expensive antibiotics, representing a significant impediment to antimicrobial stewardship. Aim of the review To (a) Explain the burden of spurious penicillin allergy, and evaluate the safety of direct oral penicillin challenge in 'low risk' patients (b) appraise the place for a clinical pharmacist-led penicillin allergy de-labelling programme. Method Narrative review. Search engines: PubMed, Google Scholar and Cochrane reviews. Search criteria: English language; search terms: penicillin allergy, antimicrobial stewardship, antimicrobial resistance, clostridium difficile, vancomycin resistant enterococci, risk stratification, clinical pharmacist and direct oral provocation test Results Penicillin allergy labels are associated with: longer hospital stay, higher readmission rates, enhanced risk of surgical site infections, risk of Clostridioides difficile infection and Methicillin resistant Staphylococcus aureus infection, a delay in the first dose of an antibiotic in sepsis and higher healthcare costs. A direct oral penicillin challenge in 'low risk' patients has proven to be safe. Discussion Recent studies including those led by a clinical pharmacist have demonstrated safety of a direct oral penicillin challenge in 'low risk' patients. This intervention needs validation within individual health services. Conclusion Direct oral penicillin challenge reduces the adverse impact of spurious penicillin allergy. A pharmacist-led penicillin allergy de-labelling program needs further validation in prospective multi-centre studies.
Collapse
Affiliation(s)
- Rashmeet Bhogal
- Department of Pharmacy, University Hospitals Birmingham NHS Foundation Trust, Birmingham, B9 5SS, UK.
| | - Abid Hussain
- Birmingham Public Health Laboratory, National Infection Service, Public Health England, Birmingham, UK
| | - Ariyur Balaji
- Department of Acute Medicine, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
| | - William H Bermingham
- Department of Allergy and Immunology, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
| | - John F Marriott
- Institute of Clinical Sciences, University of Birmingham, Birmingham, UK
| | - Mamidipudi T Krishna
- Department of Allergy and Immunology, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
- Institute of Immunology & Immunotherapy, University of Birmingham, Birmingham, UK
- Institute of Clinical Sciences, University of Birmingham, Birmingham, UK
| |
Collapse
|
7
|
Bermingham WH, Hussain A, Bhogal R, Balaji A, Krishna MT. The adverse impact of penicillin allergy labels on antimicrobial stewardship in sepsis and associated pharmacoeconomics: An observational cohort study (IMPALAS study). J Allergy Clin Immunol Pract 2020; 8:1747-1749.e4. [PMID: 31917368 DOI: 10.1016/j.jaip.2019.12.030] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Revised: 11/21/2019] [Accepted: 12/22/2019] [Indexed: 12/25/2022]
Affiliation(s)
- William Hywel Bermingham
- Department of Allergy and Immunology, University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom.
| | - Abid Hussain
- Department of Microbiology, University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom
| | - Rashmeet Bhogal
- Department of Pharmacy, University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom
| | - Ariyur Balaji
- Department of Acute Medicine, University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom
| | - Mamidipudi Thirumala Krishna
- Department of Allergy and Immunology, University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom; Institute of Immunology & Immunotherapy, University of Birmingham, Birmingham, United Kingdom
| |
Collapse
|
8
|
Kellett C, Bhogal R, Botchkareva N, Fessing M. 629 The ATP-dependent chromatin remodeler BRG1 controls epidermal keratinocytes migration during human cutaneous wound healing. J Invest Dermatol 2019. [DOI: 10.1016/j.jid.2019.07.634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
9
|
Nicu C, Hardman J, Lai T, Pople J, Bhogal R, Ansell D, Paus R. 576 The role of hepatocyte growth factor in human hair follicle – dermal white adipose tissue communication. J Invest Dermatol 2019. [DOI: 10.1016/j.jid.2019.07.580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
10
|
Kellett C, Botchkareva N, Bhogal R, Fessing M. 972 The ATP-dependent chromatin remodeler BRG1 controls epidermal keratinocytes migration during human cutaneous wound healing. J Invest Dermatol 2019. [DOI: 10.1016/j.jid.2019.03.1048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
11
|
Nicu C, Hardmann J, Lai T, Pople J, Bhogal R, Ansell D, Paus R. 922 Dermal white adipose tissue secretes hepatocyte growth factor to promote human hair follicle growth and pigmentation. J Invest Dermatol 2019. [DOI: 10.1016/j.jid.2019.03.998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
12
|
Pople J, Bhogal R, Moore A, Jenkins G. 159 Dandruff associated changes in epidermal morphology. J Invest Dermatol 2017. [DOI: 10.1016/j.jid.2017.07.469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
13
|
Brüggenjürgen B, Baker T, Bhogal R, Ahmed F. Cost impact of a non-invasive, portable device for patient self-administration of chronic migraine in a UK National Health Service setting. Springerplus 2016; 5:1249. [PMID: 27536532 PMCID: PMC4972802 DOI: 10.1186/s40064-016-2924-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 07/27/2016] [Indexed: 01/03/2023]
Abstract
BACKGROUND Chronic migraine (CM) is a neurological disorder associated with substantial disability. Botulinum toxin type A (Botox) is an approved and effective preventive treatment option for adult patients with CM. Transcranial magnetic stimulation (TMS) is an alternative treatment device delivering a brief pre-set magnetic pulse used for self-administration by the patient at home. Despite being available in a risk share scheme TMS is perceived to be more costly in the UK. The objective of this study was to analyse the incremental costs of TMS compared to Botox in refractory CM patients both for a UK individual funding request setting as well as for an average UK specialist center setting. METHODS Cost impact results were derived from a decision-tree model simulating treatment pathways over 1 year. Costs were applied from the most recently available UK data sources. Sensitivity analysis was performed for all variables. RESULTS Based on published utilisation data 45.5 % of CM patients would continuously receive Botox over 1 year, whereas 53.7 % of TMS patients would be still on treatment at the end of year one. Total costs of Botox treatment accrue to £2923 in an individual funding request NHS cost setting, whereas TMS treatment results in £1466 in the first year. Applying a time-based NHS cost setting expenditures accrue to £1747 for the Botox treatment and to £1361 for the TMS treatment. In both cost settings variation of cost assumptions did have a minor impact on the cost increment from Botox to TMS. CONCLUSION The current risk share based remuneration model of TMS allows the UK NHS to reimburse only the cost of those patients experiencing reduction in migraine days resulting in lower costs for treating migraine attacks. Treatment of chronic refractory migraine using TMS implies a substantial cost reduction potential for the management of chronic treatment of refractory migraine patients compared to conventional Botox treatment.
Collapse
Affiliation(s)
- B Brüggenjürgen
- Institute for Health Economics, Steinbeis-University, Berlin, Germany ; Institute for Social Medicine, Epidemiology and Health Economics, Charité University Medical Center, Berlin, Germany
| | - T Baker
- eNeura Inc., Sunnyvale, CA USA
| | | | - F Ahmed
- Neurosciences Business Unit, Hull and Yorkshire Hospitals NHS Trust, Hull, UK ; Hull York Medical School, Hull, UK
| |
Collapse
|
14
|
Baxter AD, Bhogal R, Bird J, Keily JF, Manallack DT, Montana JG, Owen DA, Pitt WR, Watson RJ, Wills RE. Arylsulphonyl hydroxamic acids: potent and selective matrix metalloproteinase inhibitors. Bioorg Med Chem Lett 2001; 11:1465-8. [PMID: 11378378 DOI: 10.1016/s0960-894x(01)00259-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
A series of novel matrix metalloproteinase inhibitors is described in which selectivity between MMP and 'sheddase' activity has been achieved and which demonstrate potent in vivo activity in models of arthritis and cancer.
Collapse
Affiliation(s)
- A D Baxter
- Celltech Chiroscience Ltd, Granta Park, Cambridge CB1 6GS, Abington, UK
| | | | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Lynas JF, Martin SL, Walker B, Baxter AD, Bird J, Bhogal R, Montana JG, Owen DA. Solid-phase synthesis and biological screening of N-alpha-mercaptoamide template-based matrix metalloprotease inhibitors. Comb Chem High Throughput Screen 2000; 3:37-41. [PMID: 10702612 DOI: 10.2174/1386207003327738] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A series of N-alpha-mercaptoacetyl containing dipeptides have been prepared on solid-phase supports as putative matrix metalloprotease (MMP) inhibitors. Inhibitor design was based on a positional scanning approach of the amino acids present within a template molecule, previously shown to be an MMP inhibitor with good pharmacological characteristics. This study is the first step in a unique programme, designed to expand the repertoire of molecular templates which can be chosen as starting points for the development of more focused parallel and/or combinatorial libraries of MMP inhibitors as a means to accelerate the lead discovery process. This paper reports the success of such an approach in the development of agents with activity against a number of pathologically important MMPs. After screening of these positional scanning libraries, we have obtained important SAR information, in particular, pharmacophores with the ability to impart selectivity for particular MMP species.
Collapse
Affiliation(s)
- J F Lynas
- Division of Biomedicinal Chemistry, School of Pharmacy, Queen s University Belfast, Medical Biology Centre, 79 Lisburn Road, Belfast, BT9 7BL, Northern Ireland, UK.
| | | | | | | | | | | | | | | |
Collapse
|
16
|
Sykes AP, Bhogal R, Brampton C, Chander C, Whelan C, Parsons ME, Bird J. The effect of an inhibitor of matrix metalloproteinases on colonic inflammation in a trinitrobenzenesulphonic acid rat model of inflammatory bowel disease. Aliment Pharmacol Ther 1999; 13:1535-42. [PMID: 10571613 DOI: 10.1046/j.1365-2036.1999.00633.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
BACKGROUND Recent publications have reported that matrix metalloproteinases (MMPs) are expressed in colonic tissue taken from ulcerative colitis and Crohn's disease patients. AIM To evaluate the effects of a matrix metalloproteinase inhibitor, marimastat, on colonic inflammation in experimental colitis induced by trinitrobenzenesulphonic acid (TNBS)-ethanol in the rat. METHODS Rats were dosed (by mouth) for 7 days (b.d.) with either sulphasalazine (50 mg/kg), marimastat (40 mg/kg) or vehicle. TNBS-ethanol was administered rectally on the 4th day of dosing. On the last day of dosing, colons were removed and assessed for inflammation using myeloperoxidase activity, production of soluble TNFalpha (tumour necrosis factor alpha), clinical score and histological assessment. In addition, the bioavailability and effect of marimastat on a range of MMPs were assessed in-vitro. RESULTS In this study we have confirmed that marimastat is a broad spectrum MMPI with a bioavailability of 5%. TNBS rats dosed with sulphasalazine had a significantly lower (P < 0.05) myeloperoxidase activity, TNFalpha production and a markedly lower clinical score. Similarly, rats dosed with marimastat had a significantly lower (P < 0.05) myeloperoxidase activity and clinical score, but the TNFalpha production was not significantly reduced. CONCLUSIONS Dosing rats with TNBS-induced colitis using sulphasalazine or marimastat produced a significant reduction in tissue injury and inflammation.
Collapse
Affiliation(s)
- A P Sykes
- Biosciences Department, University of Hertfordshire, Hertfordshire, UK.
| | | | | | | | | | | | | |
Collapse
|
17
|
Gawin B, Klamt B, König A, Thäte C, Le Paslier D, Chumakov I, Bhogal R, Zehetner G, Bruns G, Gessler M. An integrated YAC clone contig for the WAGR region on human chromosome 11p13-p14.1. Genomics 1995; 30:37-45. [PMID: 8595901 DOI: 10.1006/geno.1995.0006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The WAGR syndrome (Wilms tumor, aniridia, genitourinary anomalies, and mental retardation) deletion region on chromosome 11p13 has been extensively characterized by deletion analysis and long-range restriction mapping. A dense probe set is available for this genomic region, which harbors a number of disease gene loci, some of which still are not cloned. The identification of candidates for these genes would be greatly facilitated by a complete gene map for this chromosomal segment. As an initial step toward this goal, we have isolated the entire region in 58 overlapping YAC clones. The contig spanning 8 Mb from RAG1 to KCNA4 has been assembled by STS and probe content mapping for 76 loci with an average spacing of about 100 kb. A subset of clones has been analyzed by PFG analysis to position these within the known physical map. Common microsatellite markers permit an alignment of the YAC contig with the genetic and radiation hybrid maps of chromosome 11. Ten known genes, some with much more refined map positions, are placed in the contig. The severalfold coverage of 11p13-p14.1 provides a reliable resource for the future development of a complete gene map of this region.
Collapse
Affiliation(s)
- B Gawin
- Biozentrum der Universität Würzburg, Physiologische Chemiel, Germany
| | | | | | | | | | | | | | | | | | | |
Collapse
|
18
|
Bhogal R, Smith DM, Owji AA, Bloom SR. Binding sites for islet amyloid polypeptide in mammalian lung: species variation and effects on adenylyl cyclase. Can J Physiol Pharmacol 1995; 73:1030-6. [PMID: 8846396 DOI: 10.1139/y95-145] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Islet amyloid polypeptide (IAPP) and calcitonin gene related peptide (CGRP) share a 47% sequence homology. IAPP can interact with adenylyl cyclase coupled CGRP receptors. We have examined [125I]IAPP binding in mouse, pig, and guinea pig lung membranes in competition with IAPP, CGRP, and CGRP(8-37). Three types of site were shown by order of potency: (i) mouse, IAPP > CGRP(8-37) >> CGRP; (ii) pig, CGRP > IAPP > CGRP(8-37); and (iii) guinea pig, CGRP = IAPP = CGRP(8-37). Chemical cross-linking of [125I]IAPP and [125I]CGRP binding sites in lung demonstrated that both sites had similar molecular weights in any one species but differed across species, i.e., mouse M(r) = 70,000 and 98,000; pig M(r) = 68,000, 56,000, and 47,000; and guinea pig M(r) = 106,000 and 56,000. Adenylyl cyclase activity was stimulated by forskolin and AlCl3-NaF in rat, mouse, pig, and guinea pig membranes. Only in mouse and pig were CGRP and IAPP able to stimulate adenylyl cyclase activity. In mouse lung CGRP and IAPP stimulated adenylyl cyclase activity with EC50 values of 642 +/- 222 nM (n = 4) and 325 +/- 115 nM (n = 4), respectively. In pig lung membranes EC50 values were 5.7 +/- nM (n = 4) for CGRP and 1230 +/- 1130 nM (n = 4) for IAPP. Thus IAPP either did not stimulate adenylyl cyclase activity in these lung membranes or did so with a low potency.
Collapse
Affiliation(s)
- R Bhogal
- Department of Medicine, Royal Postgraduate Medical School, Hammersmith Hospital, London, United Kingdom
| | | | | | | |
Collapse
|
19
|
Hanna FW, Smith DM, Johnston CF, Akinsanya KO, Jackson ML, Morgan DG, Bhogal R, Buchanan KD, Bloom SR. Expression of a novel receptor for the calcitonin peptide family and a salmon calcitonin-like peptide in the alpha-thyrotropin thyrotroph cell line. Endocrinology 1995; 136:2377-82. [PMID: 7750458 DOI: 10.1210/endo.136.6.7750458] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
We have previously shown an increased incidence of alpha-subunit-producing thyrotroph tumors after salmon calcitonin (sCT) injection into rats. However, it is not clear whether the effects of CT are direct or indirect. Our hypothesis was that for sCT to act directly, it must have a binding site on thyrotrophs. The alpha TSH cell line was used as a model for thyrotrophs. Receptor binding studies using alpha TSH membranes revealed a high affinity binding site for sCT [IC50 = 0.97 +/- 0.18 nM (n = 4); Kd = 5.45 +/- 0.43 nM (n = 3); binding capacity = 6.6 pmol/mg protein (n = 3)]. Rat CT did not compete with binding at this site. Receptor screening for other CT peptide family members revealed high specific binding for CT gene-related peptide (CGRP; IC50 = 0.25 +/- 0.08 nM; n = 3) and islet amyloid polypeptide (IC50 = 4.36 +/- 1.1 nM; n = 3). This together with the absence of rat CT binding excluded a conventional CT-binding site, and we propose a site similar to the CGRP subtype III receptor described in the rat nucleus accumbens. Guanosine 5'O-(3-thiotriphosphate) (GTP gamma S) (20 microM), reduced [125I]CGRP binding to 38% of maximal, indicating that this site is G-protein coupled. Immunocytochemically, all of the cells displayed intense sCT-like immunoreactivity, which was totally abolished by preabsorption of the antibody with sCT. The presence of this receptor supports the hypothesis that sCT mediates tumorigenesis via a direct pituitary action and, together with the coexistence of a sCT-like peptide in these cells, provides evidence for a possible autocrine role of this peptide in the control of thyrotroph function.
Collapse
Affiliation(s)
- F W Hanna
- Department of Medicine, Wellcome Research Laboratories, Queen's University of Belfast, United Kingdom
| | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Owji AA, Smith DM, Coppock HA, Morgan DG, Bhogal R, Ghatei MA, Bloom SR. An abundant and specific binding site for the novel vasodilator adrenomedullin in the rat. Endocrinology 1995; 136:2127-34. [PMID: 7720662 DOI: 10.1210/endo.136.5.7720662] [Citation(s) in RCA: 152] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Rat adrenomedullin is a novel 50-amino acid peptide with structural similarities to the calcitonin family of peptides, calcitonin, calcitonin gene-related peptide (CGRP), and islet amyloid polypeptide (IAPP). Using rat [125I]adrenomedullin, specific binding sites were demonstrated in heart, lung, spleen, liver, soleus, diaphragm, gastrocnemius, and spinal cord membranes. The highest binding was present in heart and lung, which was further characterized. These sites exhibited saturation, dissociation, and competition. In rat lung, only rat (IC50 = 5.8 nM) and human (IC50 = 94 nM) adrenomedullin competed with [125I]adrenomedullin. However, in rat heart, rat (IC50 = 0.2 nM) and human (IC50 = 4.2 nM) adrenomedullin, IAPP (IC50 = 240 nM), and CGRP (IC50 = 1050 nM) all competed with [125I] adrenomedullin. Saturation analysis revealed binding capacities and dissociation constants of 2.8 +/- 0.3 pmol/mg protein and 1.3 +/- 0.3 nM, respectively, in lung and 0.47 +/- 0.11 pmol/mg protein and 0.41 +/- 0.14 nM in heart. Comparison with [125I]CGRP- and [125I]IAPP-binding sites in lung showed that rat adrenomedullin could potently inhibit at these sites (IC50 = 5 and 6 nM, respectively). Chemical cross-linking demonstrated a major band of 83,000 mol wt in lung, diaphragm, spleen, and liver and a band of 94,000 mol wt in heart, soleus, and gastrocnemius. Thus, [125I]adrenomedullin-binding sites in rat lung are abundant and can be differentiated from binding sites in rat heart, both pharmacologically and by mol wt.
Collapse
Affiliation(s)
- A A Owji
- Department of Medicine, Royal Postgraduate Medical School, Hammersmith Hospital, London, United Kingdom
| | | | | | | | | | | | | |
Collapse
|
21
|
Veale PR, Bhogal R, Morgan DG, Smith DM, Bloom SR. The presence of islet amyloid polypeptide/calcitonin gene-related peptide/salmon calcitonin binding sites in the rat nucleus accumbens. Eur J Pharmacol 1994; 262:133-41. [PMID: 7813564 DOI: 10.1016/0014-2999(94)90036-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Receptor autoradiographic analysis of binding in rat brain sections for [125I]islet amyloid polypeptide (IAPP), [125I]calcitonin gene-related peptide (CGRP) and [125I]salmon calcitonin indicated dense binding for all three ligands in the nucleus accumbens. Membrane binding studies revealed the existence of high affinity sites for all three peptides. The order of potency of various related peptides at each binding site was investigated and found for [125I]IAPP to be salmon calcitonin > IAPP = alpha CGRP > salmon calcitonin-(8-32); for [125I]CGRP to be alpha CGRP > IAPP > salmon calcitonin; and for [125I]salmon calcitonin to be salmon calcitonin > alpha CGRP > rat calcitonin > salmon calcitonin-(8-32) > IAPP, suggesting that [125I]IAPP targets the CGRP3 receptor subtype. This study confirms the existence of two receptors in the rat nucleus accumbens binding salmon calcitonin, one of which binds alpha CGRP and IAPP with a high affinity.
Collapse
Affiliation(s)
- P R Veale
- Department of Medicine, Royal Postgraduate Medical School, Hammersmith Hospital, London, UK
| | | | | | | | | |
Collapse
|
22
|
Abstract
Functional binding sites for [125I]IAPP and [125I]CGRP were solubilized from rat lung membranes with CHAPSO (10 mM). Rat IAPP had a higher affinity (Ki = 22.9 nM) for [125I]IAPP binding and rat alpha CGRP (Ki = 0.904 nM) had a higher affinity for [125I]CGRP binding over related peptides. [125I]IAPP binding was unaffected by GTP gamma S, but [125I]CGRP binding was 50% inhibited, indicating solubilization of a G-protein-receptor complex for CGRP but not IAPP binding. Wheat germ agglutinin affinity columns gave a 25-fold purification of IAPP binding sites, but no CGRP binding sites were eluted from the column, indicating different patterns of glycosylation of the two sites.
Collapse
Affiliation(s)
- R Bhogal
- Department of Medicine, Royal Postgraduate Medical School, Hammersmith Hospital, London, UK
| | | | | |
Collapse
|
23
|
Abstract
Neither the novel peptide, islet amyloid polypeptide (IAPP), nor its homologue, calcitonin gene-related peptide (CGRP), contracted guinea pig isolated trachea (GPT), but on preparations contracted with KCl (40 mM), both caused concentration-related relaxation (1 nM-3 microM). Relaxant curves to both were shallow and slow in development, with clear maxima not being obtained. The protease inhibitors, phosphoramidon (1 microM), leupeptin (50 microM), bestatin (100 microM), soya bean trypsin inhibitor (1 microM), and aprotinin (5 microM), together had no effect on relaxations to CGRP, but depressed those to IAPP. Aprotinin appeared to be responsible for this depression. The specific CGRP antagonist, CGRP(8-37), 1-10 microM, had no effect on relaxations to either peptide. These findings demonstrate that IAPP relaxes GPT in a similar manner to CGRP.
Collapse
Affiliation(s)
- R Bhogal
- Royal Postgraduate Medical School, Department of Medicine, Hammersmith Hospital, London, UK
| | | | | | | | | |
Collapse
|
24
|
Abstract
Neither pituitary adenylate cyclase activating polypeptide-38 (PACAP) nor its homologue, vasoactive intestinal polypeptide (VIP), contracted guinea pig isolated trachea (GPT), but on preparations contracted with KCl (40 mM), both caused concentration-related relaxation (3 nM-3 microM, VIP IC50 = 72 nM, PACAP IC50 = 224 nM). Relaxant curves to PACAP were slower in reaching a maximum than those to VIP (approximately 150 and 50 min, respectively). The protease inhibitors, phosphoramidon (1 microM), leupeptin (50 microM), bestatin (100 microM), soya bean trypsin inhibitor (1 microM), and aprotinin (5 microM), together caused a small enhancement of relaxations to VIP, but not to PACAP. The VIP antagonist, [4-Cl-D-Phe6, Leu17]VIP (1-10 microM), did not inhibit the relaxation to either peptide, but did cause large contractions, which were enhanced by protease inhibition. These findings demonstrate that PACAP relaxes GPT in a similar manner to VIP.
Collapse
Affiliation(s)
- R Bhogal
- Royal Postgraduate Medical School, Department of Medicine, Hammersmith Hospital, London, UK
| | | | | | | | | |
Collapse
|
25
|
Bhogal R, Smith DM, Purkiss P, Bloom SR. Molecular identification of binding sites for calcitonin gene-related peptide (CGRP) and islet amyloid polypeptide (IAPP) in mammalian lung: species variation and binding of truncated CGRP and IAPP. Endocrinology 1993; 133:2351-61. [PMID: 8404688 DOI: 10.1210/endo.133.5.8404688] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
We have investigated the binding of rat [125I]islet amyloid polypeptide (IAPP) and [125I]calcitonin gene-related peptide (CGRP) to lung membranes from the rat, rabbit, and bull and have characterized the mol wt (M(r)) of the binding site for each ligand by chemical crosslinking. Results imply the existence of three distinct types of binding site demonstrated by both [125I]CGRP and [125I]IAPP in each of the three species investigated. These were differentiated by the relative potencies of displacement by rat CGRP, human CGRP-(8-37), rat IAPP, and the rat IAPP fragments IAPP-(8-37), IAPP-(12-37), IAPP-(25-37), and IAPP-(28-37). High affinity binding sites were identified for [125I]CGRP [rat Ki, 0.119 +/- 0.027 nM (n = 6); rabbit Ki, 0.944 +/- 0.075 nM (n = 6); bull Ki, 0.20 +/- 0.031 nM (n = 6)], and CGRP-(8-37) was found to displace [125I]CGRP in all species [rat Ki, 6.63 +/- 0.91 nM (n = 6); rabbit Ki, 22.70 +/- 3.79 nM (n = 6); bovine Ki, 26.9 +/- 0.21 nM (n = 3)]. Compared to CGRP-(8-37), displacement by IAPP also showed varying affinities that were similar to that of CGRP-(8-37) (rat), lower than that of CGRP-(8-37) (rabbit), or higher than that of CGRP-(8-37) (bull). Truncation of IAPP caused large parallel decreases in its affinity for [125I]CGRP in the rabbit and bull by the loss of residues 1-8 (rabbit) and 1-12 (bull), but was not as pronounced in the rat. [125I]IAPP demonstrated high affinity binding in each species [rat Ki, 5.86 +/- 0.86 nM (n = 6); rabbit Ki, 18.72 +/- 2.90 nM (n = 6); bull Ki, 1.97 +/- 0.40 nM (n = 6)]. Truncation of IAPP caused a reduction of its affinity for [125I]IAPP in all species by the loss of residues 1-28. Chemical cross-linking analysis indicated binding of both ligands to sites of 64,000 M(r) in the rat and 50,500 and 51,000 M(r) in the rabbit and bull, respectively. In addition, [125I]IAPP bound to to a site of 100,000 M(r) in the rat. [125I]CGRP and [125I]IAPP binding were reduced in the presence of guanosine 5-o-(3-Thiotriphosphate) in all species, indicating an association with G-proteins. This study implies the existence of CGRP/IAPP-binding sites in the lungs of these species that show varying and complex patterns of displacement by CGRP, IAPP, and their fragments.
Collapse
Affiliation(s)
- R Bhogal
- Department of Medicine, Royal Postgraduate Medical School, Hammersmith Hospital, London, United Kingdom
| | | | | | | |
Collapse
|
26
|
Wynick D, Smith DM, Ghatei M, Akinsanya K, Bhogal R, Purkiss P, Byfield P, Yanaihara N, Bloom SR. Characterization of a high-affinity galanin receptor in the rat anterior pituitary: absence of biological effect and reduced membrane binding of the antagonist M15 differentiate it from the brain/gut receptor. Proc Natl Acad Sci U S A 1993; 90:4231-5. [PMID: 7683428 PMCID: PMC46480 DOI: 10.1073/pnas.90.9.4231] [Citation(s) in RCA: 83] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Structure-activity studies demonstrate that galanin fragments 1-15 and 2-29 are fully active, whereas fragment 3-29 has been reported to be inactive, in a number of different in vivo models. M15, a chimeric peptide comprising galanin 1-13 and substance P5-11, has recently been found to be a potent galanin antagonist. Direct effects of galanin at the level of the pituitary have been defined, yet, paradoxically, a number of studies have been unable to demonstrate galanin binding to an anterior pituitary receptor. Porcine galanin stimulated prolactin release from dispersed rat anterior pituitary cells up to 180% +/- 12% (mean +/- SEM) of control secretion. The addition of a specific galanin antiserum caused a profound inhibition of basal prolactin release, maximal inhibition being 12% +/- 0.5% of control secretion. Addition of M15 produced no effect on basal or galanin-stimulated prolactin release. Galanin fragment 3-29 was fully active when compared to galanin 1-29. Fragments 5-29 and 8-29 stimulated prolactin release to a lesser extent and galanin 1-15, 10-29, and 20-29 had no significant prolactin-releasing activity. Using [mono(125I)iodo-Tyr26]galanin or porcine 125I-labeled Bolton-Hunter [mono(125I)iodo-Lys25]galanin, no anterior pituitary membrane binding was observed. In contrast, 125I-labeled Bolton-Hunter N-terminally labeled galanin allowed characterization of a single high-affinity anterior pituitary galanin receptor with a Kd of 4.4 +/- 0.34 nM and a Bmax of 79 +/- 8.3 fmol/mg of protein. The IC50 for porcine galanin was 0.51 +/- 0.04 nM but for M15 was in excess of 10 microM. Galanin 3-29 fully displaced the label with an IC50 of 0.96 +/- 0.7 nM. The IC50 for galanin 5-29 was 200 nM, whereas 8-29 and 1-15 were > 1 microM. Galanin 10-29 and 20-29 failed to displace the label. These data suggest the presence of a high-affinity pituitary galanin receptor, designated GAL-R2, in which region 3-10 and amino acid 25 are crucial for membrane binding and biological activity, in contrast to the known gut/brain galanin receptor (designated GAL-R1). A number of tissues known to bind or respond to galanin were screened. GAL-R2 would appear to be expressed only in the anterior pituitary and hypothalamus.
Collapse
Affiliation(s)
- D Wynick
- Department of Medicine, Hammersmith Hospital, London, United Kingdom
| | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Abstract
Islet amyloid polypeptide (IAPP) is a 37-amino acid peptide shown to be cosecreted with insulin from the pancreatic beta-cells. We have investigated the existence and characteristics of IAPP binding sites in the rat. Specific binding sites for [125I]IAPP were found to be highest in the lung followed by the stomach fundus, spleen, brain stem, hypothalamus, and the liver, respectively. The interaction of [125I]IAPP with its binding site was rapid and temperature dependent, displaying optimum binding at 4 C. This may be explained by the rapid degradation of the label observed at 22 C and 37 C, as determined by fast protein liquid chromatography analysis, and also degradation of the receptor at 37 C. Binding of [125I]IAPP was rapidly dissociated by the addition of 200 nM unlabeled peptide. The presence of nonmetabolizable GTP-gamma-S (0.5 microM) reduced binding, thus suggesting the coupling of the binding site to a G protein. Rat IAPP displaced [125I]IAPP displaying an IC50 of 5.75 x 10(-9) M (mean, n = 4). Displacement was also seen with human IAPP (IC50 = 5.53 x 10(-8) M), human alpha-calcitonin gene-related peptide (CGRP) (IC50 = 3.8 x 10(-8) M), rat alpha-CGRP (IC50 = 9.0 x 10(-7) M), and rat beta-CGRP (IC50 = 5.53 x 10(-8) M); suggesting an IAPP-specific binding site. Scatchard plots for rat IAPP binding in the lung gave a dissociation constant of 10.4 +/- 2.63 nM (mean +/- SE, n = 4) and maximal binding of 3.1 +/- 0.97 pmol/mg (mean +/- SE, n = 4), displaying a single class of binding site. Chemical cross-linking analysis showed binding of IAPP to sites of Mr 67,000, 64,000, and 38,000. These findings suggest that specific IAPP binding sites exist which differ from the CGRP receptors in rat tissues. This indicates a possible novel autocrine/paracrine role for IAPP.
Collapse
Affiliation(s)
- R Bhogal
- Department of Medicine, Royal Postgraduate Medical School, Hammersmith Hospital, London, United Kingdom
| | | | | |
Collapse
|